server/backup/BackupManagerService.java

/*
 * Copyright (C) 2009 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.server.backup;

import static android.app.backup.BackupManagerMonitor.EXTRA_LOG_EVENT_PACKAGE_NAME;
import static android.app.backup.BackupManagerMonitor.EXTRA_LOG_EVENT_PACKAGE_VERSION;
import static android.app.backup.BackupManagerMonitor.EXTRA_LOG_OLD_VERSION;
import static android.app.backup.BackupManagerMonitor.EXTRA_LOG_POLICY_ALLOW_APKS;
import static android.app.backup.BackupManagerMonitor.EXTRA_LOG_MANIFEST_PACKAGE_NAME;
import static android.app.backup.BackupManagerMonitor.LOG_EVENT_CATEGORY_AGENT;
import static android.app.backup.BackupManagerMonitor.LOG_EVENT_CATEGORY_BACKUP_MANAGER_POLICY;
import static android.app.backup.BackupManagerMonitor.LOG_EVENT_ID_VERSION_OF_BACKUP_OLDER;
import static android.app.backup.BackupManagerMonitor.LOG_EVENT_ID_FULL_RESTORE_SIGNATURE_MISMATCH;
import static android.app.backup.BackupManagerMonitor.LOG_EVENT_ID_SYSTEM_APP_NO_AGENT;
import static android.app.backup.BackupManagerMonitor.LOG_EVENT_ID_FULL_RESTORE_ALLOW_BACKUP_FALSE;
import static android.app.backup.BackupManagerMonitor.LOG_EVENT_ID_APK_NOT_INSTALLED;
import static android.app.backup.BackupManagerMonitor.LOG_EVENT_ID_CANNOT_RESTORE_WITHOUT_APK;
import static android.app.backup.BackupManagerMonitor.LOG_EVENT_ID_MISSING_SIGNATURE;
import static android.app.backup.BackupManagerMonitor.LOG_EVENT_ID_EXPECTED_DIFFERENT_PACKAGE;
import static android.app.backup.BackupManagerMonitor.LOG_EVENT_ID_RESTORE_ANY_VERSION;
import static android.app.backup.BackupManagerMonitor.LOG_EVENT_ID_VERSIONS_MATCH;
import static android.content.pm.ApplicationInfo.PRIVATE_FLAG_BACKUP_IN_FOREGROUND;

import android.app.ActivityManager;
import android.app.AlarmManager;
import android.app.AppGlobals;
import android.app.ApplicationThreadConstants;
import android.app.IActivityManager;
import android.app.IBackupAgent;
import android.app.PackageInstallObserver;
import android.app.PendingIntent;
import android.app.backup.BackupAgent;
import android.app.backup.BackupDataInput;
import android.app.backup.BackupDataOutput;
import android.app.backup.BackupManager;
import android.app.backup.BackupManagerMonitor;
import android.app.backup.BackupProgress;
import android.app.backup.BackupTransport;
import android.app.backup.FullBackup;
import android.app.backup.FullBackupDataOutput;
import android.app.backup.IBackupManager;
import android.app.backup.IBackupManagerMonitor;
import android.app.backup.IBackupObserver;
import android.app.backup.IFullBackupRestoreObserver;
import android.app.backup.IRestoreObserver;
import android.app.backup.IRestoreSession;
import android.app.backup.ISelectBackupTransportCallback;
import android.app.backup.RestoreDescription;
import android.app.backup.RestoreSet;
import android.app.backup.SelectBackupTransportCallback;
import android.content.ActivityNotFoundException;
import android.content.BroadcastReceiver;
import android.content.ComponentName;
import android.content.ContentResolver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.ServiceConnection;
import android.content.pm.ApplicationInfo;
import android.content.pm.IPackageDataObserver;
import android.content.pm.IPackageDeleteObserver;
import android.content.pm.IPackageManager;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager;
import android.content.pm.PackageManager.NameNotFoundException;
import android.content.pm.Signature;
import android.database.ContentObserver;
import android.net.Uri;
import android.os.PowerSaveState;
import android.os.Binder;
import android.os.Build;
import android.os.Bundle;
import android.os.Environment;
import android.os.Environment.UserEnvironment;
import android.os.Handler;
import android.os.HandlerThread;
import android.os.IBinder;
import android.os.Looper;
import android.os.Message;
import android.os.ParcelFileDescriptor;
import android.os.PowerManager;
import android.os.Process;
import android.os.RemoteException;
import android.os.SELinux;
import android.os.ServiceManager;
import android.os.SystemClock;
import android.os.Trace;
import android.os.UserHandle;
import android.os.WorkSource;
import android.os.storage.IStorageManager;
import android.os.storage.StorageManager;
import android.provider.Settings;
import android.system.ErrnoException;
import android.system.Os;
import android.text.TextUtils;
import android.util.ArraySet;
import android.util.AtomicFile;
import android.util.EventLog;
import android.util.Log;
import android.util.Pair;
import android.util.Slog;
import android.util.SparseArray;
import android.util.StringBuilderPrinter;

import com.android.internal.annotations.GuardedBy;
import com.android.internal.backup.IBackupTransport;
import com.android.internal.backup.IObbBackupService;
import com.android.internal.util.DumpUtils;
import com.android.server.AppWidgetBackupBridge;
import com.android.server.EventLogTags;
import com.android.server.SystemConfig;
import com.android.server.SystemService;
import com.android.server.backup.PackageManagerBackupAgent.Metadata;
import com.android.server.power.BatterySaverPolicy.ServiceType;

import libcore.io.IoUtils;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.EOFException;
import java.io.File;
import java.io.FileDescriptor;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.io.RandomAccessFile;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.Key;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.KeySpec;
import java.text.SimpleDateFormat;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Date;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map.Entry;
import java.util.Objects;
import java.util.Queue;
import java.util.Random;
import java.util.Set;
import java.util.TreeMap;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicLong;
import java.util.zip.Deflater;
import java.util.zip.DeflaterOutputStream;
import java.util.zip.InflaterInputStream;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.CipherInputStream;
import javax.crypto.CipherOutputStream;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.SecretKeySpec;

public class BackupManagerService implements BackupManagerServiceInterface {

    private static final String TAG = "BackupManagerService";
    static final boolean DEBUG = true;
    static final boolean MORE_DEBUG = false;
    static final boolean DEBUG_SCHEDULING = MORE_DEBUG || true;

    // File containing backup-enabled state.  Contains a single byte;
    // nonzero == enabled.  File missing or contains a zero byte == disabled.
    static final String BACKUP_ENABLE_FILE = "backup_enabled";

    // System-private key used for backing up an app's widget state.  Must
    // begin with U+FFxx by convention (we reserve all keys starting
    // with U+FF00 or higher for system use).
    static final String KEY_WIDGET_STATE = "\uffed\uffedwidget";

    // Historical and current algorithm names
    static final String PBKDF_CURRENT = "PBKDF2WithHmacSHA1";
    static final String PBKDF_FALLBACK = "PBKDF2WithHmacSHA1And8bit";

    // Name and current contents version of the full-backup manifest file
    //
    // Manifest version history:
    //
    // 1 : initial release
    static final String BACKUP_MANIFEST_FILENAME = "_manifest";
    static final int BACKUP_MANIFEST_VERSION = 1;

    // External archive format version history:
    //
    // 1 : initial release
    // 2 : no format change per se; version bump to facilitate PBKDF2 version skew detection
    // 3 : introduced "_meta" metadata file; no other format change per se
    // 4 : added support for new device-encrypted storage locations
    // 5 : added support for key-value packages
    static final int BACKUP_FILE_VERSION = 5;
    static final String BACKUP_FILE_HEADER_MAGIC = "ANDROID BACKUP\n";
    static final int BACKUP_PW_FILE_VERSION = 2;
    static final String BACKUP_METADATA_FILENAME = "_meta";
    static final int BACKUP_METADATA_VERSION = 1;
    static final int BACKUP_WIDGET_METADATA_TOKEN = 0x01FFED01;

    static final int TAR_HEADER_LONG_RADIX = 8;
    static final int TAR_HEADER_OFFSET_FILESIZE = 124;
    static final int TAR_HEADER_LENGTH_FILESIZE = 12;
    static final int TAR_HEADER_OFFSET_MODTIME = 136;
    static final int TAR_HEADER_LENGTH_MODTIME = 12;
    static final int TAR_HEADER_OFFSET_MODE = 100;
    static final int TAR_HEADER_LENGTH_MODE = 8;
    static final int TAR_HEADER_OFFSET_PATH_PREFIX = 345;
    static final int TAR_HEADER_LENGTH_PATH_PREFIX = 155;
    static final int TAR_HEADER_OFFSET_PATH = 0;
    static final int TAR_HEADER_LENGTH_PATH = 100;
    static final int TAR_HEADER_OFFSET_TYPE_CHAR = 156;

    static final boolean COMPRESS_FULL_BACKUPS = true; // should be true in production

    static final String SETTINGS_PACKAGE = "com.android.providers.settings";
    static final String SHARED_BACKUP_AGENT_PACKAGE = "com.android.sharedstoragebackup";
    static final String SERVICE_ACTION_TRANSPORT_HOST = "android.backup.TRANSPORT_HOST";

    // Retry interval for clear/init when the transport is unavailable
    private static final long TRANSPORT_RETRY_INTERVAL = 1 * AlarmManager.INTERVAL_HOUR;

    private static final String RUN_BACKUP_ACTION = "android.app.backup.intent.RUN";
    private static final String RUN_INITIALIZE_ACTION = "android.app.backup.intent.INIT";
    private static final int MSG_RUN_BACKUP = 1;
    private static final int MSG_RUN_ADB_BACKUP = 2;
    private static final int MSG_RUN_RESTORE = 3;
    private static final int MSG_RUN_CLEAR = 4;
    private static final int MSG_RUN_GET_RESTORE_SETS = 6;
    private static final int MSG_RESTORE_SESSION_TIMEOUT = 8;
    private static final int MSG_FULL_CONFIRMATION_TIMEOUT = 9;
    private static final int MSG_RUN_ADB_RESTORE = 10;
    private static final int MSG_RETRY_INIT = 11;
    private static final int MSG_RETRY_CLEAR = 12;
    private static final int MSG_WIDGET_BROADCAST = 13;
    private static final int MSG_RUN_FULL_TRANSPORT_BACKUP = 14;
    private static final int MSG_REQUEST_BACKUP = 15;
    private static final int MSG_SCHEDULE_BACKUP_PACKAGE = 16;
    private static final int MSG_BACKUP_OPERATION_TIMEOUT = 17;
    private static final int MSG_RESTORE_OPERATION_TIMEOUT = 18;

    // backup task state machine tick
    static final int MSG_BACKUP_RESTORE_STEP = 20;
    static final int MSG_OP_COMPLETE = 21;

    // Timeout interval for deciding that a bind or clear-data has taken too long
    static final long TIMEOUT_INTERVAL = 10 * 1000;

    // Timeout intervals for agent backup & restore operations
    static final long TIMEOUT_BACKUP_INTERVAL = 30 * 1000;
    static final long TIMEOUT_FULL_BACKUP_INTERVAL = 5 * 60 * 1000;
    static final long TIMEOUT_SHARED_BACKUP_INTERVAL = 30 * 60 * 1000;
    static final long TIMEOUT_RESTORE_INTERVAL = 60 * 1000;
    static final long TIMEOUT_RESTORE_FINISHED_INTERVAL = 30 * 1000;

    // User confirmation timeout for a full backup/restore operation.  It's this long in
    // order to give them time to enter the backup password.
    static final long TIMEOUT_FULL_CONFIRMATION = 60 * 1000;

    // How long between attempts to perform a full-data backup of any given app
    static final long MIN_FULL_BACKUP_INTERVAL = 1000 * 60 * 60 * 24; // one day

    // If an app is busy when we want to do a full-data backup, how long to defer the retry.
    // This is fuzzed, so there are two parameters; backoff_min + Rand[0, backoff_fuzz)
    static final long BUSY_BACKOFF_MIN_MILLIS = 1000 * 60 * 60;  // one hour
    static final int BUSY_BACKOFF_FUZZ = 1000 * 60 * 60 * 2;  // two hours

    Context mContext;
    private PackageManager mPackageManager;
    IPackageManager mPackageManagerBinder;
    private IActivityManager mActivityManager;
    private PowerManager mPowerManager;
    private AlarmManager mAlarmManager;
    private IStorageManager mStorageManager;

    IBackupManager mBackupManagerBinder;

    private final TransportManager mTransportManager;

    boolean mEnabled;   // access to this is synchronized on 'this'
    boolean mProvisioned;
    boolean mAutoRestore;
    PowerManager.WakeLock mWakelock;
    HandlerThread mHandlerThread;
    BackupHandler mBackupHandler;
    PendingIntent mRunBackupIntent, mRunInitIntent;
    BroadcastReceiver mRunBackupReceiver, mRunInitReceiver;
    // map UIDs to the set of participating packages under that UID
    final SparseArray<HashSet<String>> mBackupParticipants
            = new SparseArray<HashSet<String>>();
    // set of backup services that have pending changes
    class BackupRequest {
        public String packageName;

        BackupRequest(String pkgName) {
            packageName = pkgName;
        }

        public String toString() {
            return "BackupRequest{pkg=" + packageName + "}";
        }
    }
    // Backups that we haven't started yet.  Keys are package names.
    HashMap<String,BackupRequest> mPendingBackups
            = new HashMap<String,BackupRequest>();

    // Pseudoname that we use for the Package Manager metadata "package"
    static final String PACKAGE_MANAGER_SENTINEL = "@pm@";

    // locking around the pending-backup management
    final Object mQueueLock = new Object();

    // The thread performing the sequence of queued backups binds to each app's agent
    // in succession.  Bind notifications are asynchronously delivered through the
    // Activity Manager; use this lock object to signal when a requested binding has
    // completed.
    final Object mAgentConnectLock = new Object();
    IBackupAgent mConnectedAgent;
    volatile boolean mBackupRunning;
    volatile boolean mConnecting;
    volatile long mLastBackupPass;

    // For debugging, we maintain a progress trace of operations during backup
    static final boolean DEBUG_BACKUP_TRACE = true;
    final List<String> mBackupTrace = new ArrayList<String>();

    // A similar synchronization mechanism around clearing apps' data for restore
    final Object mClearDataLock = new Object();
    volatile boolean mClearingData;

    @GuardedBy("mPendingRestores")
    private boolean mIsRestoreInProgress;
    @GuardedBy("mPendingRestores")
    private final Queue<PerformUnifiedRestoreTask> mPendingRestores = new ArrayDeque<>();

    ActiveRestoreSession mActiveRestoreSession;

    // Watch the device provisioning operation during setup
    ContentObserver mProvisionedObserver;

    // The published binder is actually to a singleton trampoline object that calls
    // through to the proper code.  This indirection lets us turn down the heavy
    // implementation object on the fly without disturbing binders that have been
    // cached elsewhere in the system.
    static Trampoline sInstance;
    static Trampoline getInstance() {
        // Always constructed during system bringup, so no need to lazy-init
        return sInstance;
    }

    public static final class Lifecycle extends SystemService {

        public Lifecycle(Context context) {
            super(context);
            sInstance = new Trampoline(context);
        }

        @Override
        public void onStart() {
            publishBinderService(Context.BACKUP_SERVICE, sInstance);
        }

        @Override
        public void onUnlockUser(int userId) {
            if (userId == UserHandle.USER_SYSTEM) {
                Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "backup init");
                sInstance.initialize(userId);
                Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);

                // Migrate legacy setting
                Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "backup migrate");
                if (!backupSettingMigrated(userId)) {
                    if (DEBUG) {
                        Slog.i(TAG, "Backup enable apparently not migrated");
                    }
                    final ContentResolver r = sInstance.mContext.getContentResolver();
                    final int enableState = Settings.Secure.getIntForUser(r,
                            Settings.Secure.BACKUP_ENABLED, -1, userId);
                    if (enableState >= 0) {
                        if (DEBUG) {
                            Slog.i(TAG, "Migrating enable state " + (enableState != 0));
                        }
                        writeBackupEnableState(enableState != 0, userId);
                        Settings.Secure.putStringForUser(r,
                                Settings.Secure.BACKUP_ENABLED, null, userId);
                    } else {
                        if (DEBUG) {
                            Slog.i(TAG, "Backup not yet configured; retaining null enable state");
                        }
                    }
                }
                Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);

                Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "backup enable");
                try {
                    sInstance.setBackupEnabled(readBackupEnableState(userId));
                } catch (RemoteException e) {
                    // can't happen; it's a local object
                }
                Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
            }
        }
    }

    class ProvisionedObserver extends ContentObserver {
        public ProvisionedObserver(Handler handler) {
            super(handler);
        }

        public void onChange(boolean selfChange) {
            final boolean wasProvisioned = mProvisioned;
            final boolean isProvisioned = deviceIsProvisioned();
            // latch: never unprovision
            mProvisioned = wasProvisioned || isProvisioned;
            if (MORE_DEBUG) {
                Slog.d(TAG, "Provisioning change: was=" + wasProvisioned
                        + " is=" + isProvisioned + " now=" + mProvisioned);
            }

            synchronized (mQueueLock) {
                if (mProvisioned && !wasProvisioned && mEnabled) {
                    // we're now good to go, so start the backup alarms
                    if (MORE_DEBUG) Slog.d(TAG, "Now provisioned, so starting backups");
                    KeyValueBackupJob.schedule(mContext);
                    scheduleNextFullBackupJob(0);
                }
            }
        }
    }

    class RestoreGetSetsParams {
        public IBackupTransport transport;
        public ActiveRestoreSession session;
        public IRestoreObserver observer;
        public IBackupManagerMonitor monitor;

        RestoreGetSetsParams(IBackupTransport _transport, ActiveRestoreSession _session,
                IRestoreObserver _observer, IBackupManagerMonitor _monitor) {
            transport = _transport;
            session = _session;
            observer = _observer;
            monitor = _monitor;
        }
    }

    class RestoreParams {
        public IBackupTransport transport;
        public String dirName;
        public IRestoreObserver observer;
        public IBackupManagerMonitor monitor;
        public long token;
        public PackageInfo pkgInfo;
        public int pmToken; // in post-install restore, the PM's token for this transaction
        public boolean isSystemRestore;
        public String[] filterSet;

        /**
         * Restore a single package; no kill after restore
         */
        RestoreParams(IBackupTransport _transport, String _dirName, IRestoreObserver _obs,
                IBackupManagerMonitor _monitor, long _token, PackageInfo _pkg) {
            transport = _transport;
            dirName = _dirName;
            observer = _obs;
            monitor = _monitor;
            token = _token;
            pkgInfo = _pkg;
            pmToken = 0;
            isSystemRestore = false;
            filterSet = null;
        }

        /**
         * Restore at install: PM token needed, kill after restore
         */
        RestoreParams(IBackupTransport _transport, String _dirName, IRestoreObserver _obs,
                IBackupManagerMonitor _monitor, long _token, String _pkgName, int _pmToken) {
            transport = _transport;
            dirName = _dirName;
            observer = _obs;
            monitor = _monitor;
            token = _token;
            pkgInfo = null;
            pmToken = _pmToken;
            isSystemRestore = false;
            filterSet = new String[] { _pkgName };
        }

        /**
         * Restore everything possible.  This is the form that Setup Wizard or similar
         * restore UXes use.
         */
        RestoreParams(IBackupTransport _transport, String _dirName, IRestoreObserver _obs,
                IBackupManagerMonitor _monitor, long _token) {
            transport = _transport;
            dirName = _dirName;
            observer = _obs;
            monitor = _monitor;
            token = _token;
            pkgInfo = null;
            pmToken = 0;
            isSystemRestore = true;
            filterSet = null;
        }

        /**
         * Restore some set of packages.  Leave this one up to the caller to specify
         * whether it's to be considered a system-level restore.
         */
        RestoreParams(IBackupTransport _transport, String _dirName, IRestoreObserver _obs,
                IBackupManagerMonitor _monitor, long _token,
                String[] _filterSet, boolean _isSystemRestore) {
            transport = _transport;
            dirName = _dirName;
            observer = _obs;
            monitor = _monitor;
            token = _token;
            pkgInfo = null;
            pmToken = 0;
            isSystemRestore = _isSystemRestore;
            filterSet = _filterSet;
        }
    }

    class ClearParams {
        public IBackupTransport transport;
        public PackageInfo packageInfo;

        ClearParams(IBackupTransport _transport, PackageInfo _info) {
            transport = _transport;
            packageInfo = _info;
        }
    }

    class ClearRetryParams {
        public String transportName;
        public String packageName;

        ClearRetryParams(String transport, String pkg) {
            transportName = transport;
            packageName = pkg;
        }
    }

    // Parameters used by adbBackup() and adbRestore()
    class AdbParams {
        public ParcelFileDescriptor fd;
        public final AtomicBoolean latch;
        public IFullBackupRestoreObserver observer;
        public String curPassword;     // filled in by the confirmation step
        public String encryptPassword;

        AdbParams() {
            latch = new AtomicBoolean(false);
        }
    }

    class AdbBackupParams extends AdbParams {
        public boolean includeApks;
        public boolean includeObbs;
        public boolean includeShared;
        public boolean doWidgets;
        public boolean allApps;
        public boolean includeSystem;
        public boolean doCompress;
        public boolean includeKeyValue;
        public String[] packages;

        AdbBackupParams(ParcelFileDescriptor output, boolean saveApks, boolean saveObbs,
                boolean saveShared, boolean alsoWidgets, boolean doAllApps, boolean doSystem,
                boolean compress, boolean doKeyValue, String[] pkgList) {
            fd = output;
            includeApks = saveApks;
            includeObbs = saveObbs;
            includeShared = saveShared;
            doWidgets = alsoWidgets;
            allApps = doAllApps;
            includeSystem = doSystem;
            doCompress = compress;
            includeKeyValue = doKeyValue;
            packages = pkgList;
        }
    }

    class AdbRestoreParams extends AdbParams {
        AdbRestoreParams(ParcelFileDescriptor input) {
            fd = input;
        }
    }

    class BackupParams {
        public IBackupTransport transport;
        public String dirName;
        public ArrayList<String> kvPackages;
        public ArrayList<String> fullPackages;
        public IBackupObserver observer;
        public IBackupManagerMonitor monitor;
        public boolean userInitiated;
        public boolean nonIncrementalBackup;

        BackupParams(IBackupTransport transport, String dirName, ArrayList<String> kvPackages,
                ArrayList<String> fullPackages, IBackupObserver observer,
                IBackupManagerMonitor monitor,boolean userInitiated, boolean nonIncrementalBackup) {
            this.transport = transport;
            this.dirName = dirName;
            this.kvPackages = kvPackages;
            this.fullPackages = fullPackages;
            this.observer = observer;
            this.monitor = monitor;
            this.userInitiated = userInitiated;
            this.nonIncrementalBackup = nonIncrementalBackup;
        }
    }

    // Bookkeeping of in-flight operations for timeout etc. purposes.  The operation
    // token is the index of the entry in the pending-operations list.
    static final int OP_PENDING = 0;
    static final int OP_ACKNOWLEDGED = 1;
    static final int OP_TIMEOUT = -1;

    // Waiting for backup agent to respond during backup operation.
    static final int OP_TYPE_BACKUP_WAIT = 0;

    // Waiting for backup agent to respond during restore operation.
    static final int OP_TYPE_RESTORE_WAIT = 1;

    // An entire backup operation spanning multiple packages.
    private static final int OP_TYPE_BACKUP = 2;

    class Operation {
        int state;
        final BackupRestoreTask callback;
        final int type;

        Operation(int initialState, BackupRestoreTask callbackObj, int type) {
            state = initialState;
            callback = callbackObj;
            this.type = type;
        }
    }

    /**
     * mCurrentOperations contains the list of currently active operations.
     *
     * If type of operation is OP_TYPE_WAIT, it are waiting for an ack or timeout.
     * An operation wraps a BackupRestoreTask within it.
     * It's the responsibility of this task to remove the operation from this array.
     *
     * A BackupRestore task gets notified of ack/timeout for the operation via
     * BackupRestoreTask#handleCancel, BackupRestoreTask#operationComplete and notifyAll called
     * on the mCurrentOpLock. {@link BackupManagerService#waitUntilOperationComplete(int)} is
     * used in various places to 'wait' for notifyAll and detect change of pending state of an
     * operation. So typically, an operation will be removed from this array by:
     *   - BackupRestoreTask#handleCancel and
     *   - BackupRestoreTask#operationComplete OR waitUntilOperationComplete. Do not remove at both
     *     these places because waitUntilOperationComplete relies on the operation being present to
     *     determine its completion status.
     *
     * If type of operation is OP_BACKUP, it is a task running backups. It provides a handle to
     * cancel backup tasks.
     */
    @GuardedBy("mCurrentOpLock")
    final SparseArray<Operation> mCurrentOperations = new SparseArray<Operation>();
    final Object mCurrentOpLock = new Object();
    final Random mTokenGenerator = new Random();

    final SparseArray<AdbParams> mAdbBackupRestoreConfirmations = new SparseArray<AdbParams>();

    // Where we keep our journal files and other bookkeeping
    File mBaseStateDir;
    File mDataDir;
    File mJournalDir;
    File mJournal;

    // Backup password, if any, and the file where it's saved.  What is stored is not the
    // password text itself; it's the result of a PBKDF2 hash with a randomly chosen (but
    // persisted) salt.  Validation is performed by running the challenge text through the
    // same PBKDF2 cycle with the persisted salt; if the resulting derived key string matches
    // the saved hash string, then the challenge text matches the originally supplied
    // password text.
    private final SecureRandom mRng = new SecureRandom();
    private String mPasswordHash;
    private File mPasswordHashFile;
    private int mPasswordVersion;
    private File mPasswordVersionFile;
    private byte[] mPasswordSalt;

    // Configuration of PBKDF2 that we use for generating pw hashes and intermediate keys
    static final int PBKDF2_HASH_ROUNDS = 10000;
    static final int PBKDF2_KEY_SIZE = 256;     // bits
    static final int PBKDF2_SALT_SIZE = 512;    // bits
    static final String ENCRYPTION_ALGORITHM_NAME = "AES-256";

    // Keep a log of all the apps we've ever backed up, and what the
    // dataset tokens are for both the current backup dataset and
    // the ancestral dataset.
    private File mEverStored;
    HashSet<String> mEverStoredApps = new HashSet<String>();

    static final int CURRENT_ANCESTRAL_RECORD_VERSION = 1;  // increment when the schema changes
    File mTokenFile;
    Set<String> mAncestralPackages = null;
    long mAncestralToken = 0;
    long mCurrentToken = 0;

    // Persistently track the need to do a full init
    static final String INIT_SENTINEL_FILE_NAME = "_need_init_";
    ArraySet<String> mPendingInits = new ArraySet<String>();  // transport names

    // Round-robin queue for scheduling full backup passes
    static final int SCHEDULE_FILE_VERSION = 1; // current version of the schedule file
    class FullBackupEntry implements Comparable<FullBackupEntry> {
        String packageName;
        long lastBackup;

        FullBackupEntry(String pkg, long when) {
            packageName = pkg;
            lastBackup = when;
        }

        @Override
        public int compareTo(FullBackupEntry other) {
            if (lastBackup < other.lastBackup) return -1;
            else if (lastBackup > other.lastBackup) return 1;
            else return 0;
        }
    }

    File mFullBackupScheduleFile;
    // If we're running a schedule-driven full backup, this is the task instance doing it

    @GuardedBy("mQueueLock")
    PerformFullTransportBackupTask mRunningFullBackupTask;

    @GuardedBy("mQueueLock")
    ArrayList<FullBackupEntry> mFullBackupQueue;

    // Utility: build a new random integer token
    @Override
    public int generateRandomIntegerToken() {
        int token;
        do {
            synchronized (mTokenGenerator) {
                token = mTokenGenerator.nextInt();
            }
        } while (token < 0);
        return token;
    }

    // High level policy: apps are generally ineligible for backup if certain conditions apply
    public static boolean appIsEligibleForBackup(ApplicationInfo app, PackageManager pm) {
        // 1. their manifest states android:allowBackup="false"
        if ((app.flags&ApplicationInfo.FLAG_ALLOW_BACKUP) == 0) {
            return false;
        }

        // 2. they run as a system-level uid but do not supply their own backup agent
        if ((app.uid < Process.FIRST_APPLICATION_UID) && (app.backupAgentName == null)) {
            return false;
        }

        // 3. it is the special shared-storage backup package used for 'adb backup'
        if (app.packageName.equals(BackupManagerService.SHARED_BACKUP_AGENT_PACKAGE)) {
            return false;
        }

        // 4. it is an "instant" app
        if (app.isInstantApp()) {
            return false;
        }

        // Everything else checks out; the only remaining roadblock would be if the
        // package were disabled
        return !appIsDisabled(app, pm);
    }

    // Checks if the app is in a stopped state.  This is not part of the general "eligible for
    // backup?" check because we *do* still need to restore data to apps in this state (e.g.
    // newly-installing ones)
    private static boolean appIsStopped(ApplicationInfo app) {
        return ((app.flags & ApplicationInfo.FLAG_STOPPED) != 0);
    }

    private static boolean appIsDisabled(ApplicationInfo app, PackageManager pm) {
        switch (pm.getApplicationEnabledSetting(app.packageName)) {
            case PackageManager.COMPONENT_ENABLED_STATE_DISABLED:
            case PackageManager.COMPONENT_ENABLED_STATE_DISABLED_USER:
            case PackageManager.COMPONENT_ENABLED_STATE_DISABLED_UNTIL_USED:
                return true;

            default:
                return false;
        }
    }

    /* does *not* check overall backup eligibility policy! */
    private static boolean appGetsFullBackup(PackageInfo pkg) {
        if (pkg.applicationInfo.backupAgentName != null) {
            // If it has an agent, it gets full backups only if it says so
            return (pkg.applicationInfo.flags & ApplicationInfo.FLAG_FULL_BACKUP_ONLY) != 0;
        }

        // No agent or fullBackupOnly="true" means we do indeed perform full-data backups for it
        return true;
    }

    /* adb backup: is this app only capable of doing key/value?  We say otherwise if
     * the app has a backup agent and does not say fullBackupOnly,
     */
    private static boolean appIsKeyValueOnly(PackageInfo pkg) {
        return !appGetsFullBackup(pkg);
    }

    /*
     * Construct a backup agent instance for the metadata pseudopackage.  This is a
     * process-local non-lifecycle agent instance, so we manually set up the context
     * topology for it.
     */
    PackageManagerBackupAgent makeMetadataAgent() {
        PackageManagerBackupAgent pmAgent = new PackageManagerBackupAgent(mPackageManager);
        pmAgent.attach(mContext);
        pmAgent.onCreate();
        return pmAgent;
    }

    /*
     * Same as above but with the explicit package-set configuration.
     */
    PackageManagerBackupAgent makeMetadataAgent(List<PackageInfo> packages) {
        PackageManagerBackupAgent pmAgent =
                new PackageManagerBackupAgent(mPackageManager, packages);
        pmAgent.attach(mContext);
        pmAgent.onCreate();
        return pmAgent;
    }

    // ----- Asynchronous backup/restore handler thread -----

    private class BackupHandler extends Handler {
        public BackupHandler(Looper looper) {
            super(looper);
        }

        public void handleMessage(Message msg) {

            switch (msg.what) {
            case MSG_RUN_BACKUP:
            {
                mLastBackupPass = System.currentTimeMillis();

                IBackupTransport transport = mTransportManager.getCurrentTransportBinder();
                if (transport == null) {
                    Slog.v(TAG, "Backup requested but no transport available");
                    synchronized (mQueueLock) {
                        mBackupRunning = false;
                    }
                    mWakelock.release();
                    break;
                }

                // snapshot the pending-backup set and work on that
                ArrayList<BackupRequest> queue = new ArrayList<BackupRequest>();
                File oldJournal = mJournal;
                synchronized (mQueueLock) {
                    // Do we have any work to do?  Construct the work queue
                    // then release the synchronization lock to actually run
                    // the backup.
                    if (mPendingBackups.size() > 0) {
                        for (BackupRequest b: mPendingBackups.values()) {
                            queue.add(b);
                        }
                        if (DEBUG) Slog.v(TAG, "clearing pending backups");
                        mPendingBackups.clear();

                        // Start a new backup-queue journal file too
                        mJournal = null;

                    }
                }

                // At this point, we have started a new journal file, and the old
                // file identity is being passed to the backup processing task.
                // When it completes successfully, that old journal file will be
                // deleted.  If we crash prior to that, the old journal is parsed
                // at next boot and the journaled requests fulfilled.
                boolean staged = true;
                if (queue.size() > 0) {
                    // Spin up a backup state sequence and set it running
                    try {
                        String dirName = transport.transportDirName();
                        PerformBackupTask pbt = new PerformBackupTask(transport, dirName, queue,
                                oldJournal, null, null, Collections.<String>emptyList(), false,
                                false /* nonIncremental */);
                        Message pbtMessage = obtainMessage(MSG_BACKUP_RESTORE_STEP, pbt);
                        sendMessage(pbtMessage);
                    } catch (Exception e) {
                        // unable to ask the transport its dir name -- transient failure, since
                        // the above check succeeded.  Try again next time.
                        Slog.e(TAG, "Transport became unavailable attempting backup"
                                + " or error initializing backup task", e);
                        staged = false;
                    }
                } else {
                    Slog.v(TAG, "Backup requested but nothing pending");
                    staged = false;
                }

                if (!staged) {
                    // if we didn't actually hand off the wakelock, rewind until next time
                    synchronized (mQueueLock) {
                        mBackupRunning = false;
                    }
                    mWakelock.release();
                }
                break;
            }

            case MSG_BACKUP_RESTORE_STEP:
            {
                try {
                    BackupRestoreTask task = (BackupRestoreTask) msg.obj;
                    if (MORE_DEBUG) Slog.v(TAG, "Got next step for " + task + ", executing");
                    task.execute();
                } catch (ClassCastException e) {
                    Slog.e(TAG, "Invalid backup task in flight, obj=" + msg.obj);
                }
                break;
            }

            case MSG_OP_COMPLETE:
            {
                try {
                    Pair<BackupRestoreTask, Long> taskWithResult =
                            (Pair<BackupRestoreTask, Long>) msg.obj;
                    taskWithResult.first.operationComplete(taskWithResult.second);
                } catch (ClassCastException e) {
                    Slog.e(TAG, "Invalid completion in flight, obj=" + msg.obj);
                }
                break;
            }

            case MSG_RUN_ADB_BACKUP:
            {
                // TODO: refactor full backup to be a looper-based state machine
                // similar to normal backup/restore.
                AdbBackupParams params = (AdbBackupParams)msg.obj;
                PerformAdbBackupTask task = new PerformAdbBackupTask(params.fd,
                        params.observer, params.includeApks, params.includeObbs,
                        params.includeShared, params.doWidgets, params.curPassword,
                        params.encryptPassword, params.allApps, params.includeSystem,
                        params.doCompress, params.includeKeyValue, params.packages, params.latch);
                (new Thread(task, "adb-backup")).start();
                break;
            }

            case MSG_RUN_FULL_TRANSPORT_BACKUP:
            {
                PerformFullTransportBackupTask task = (PerformFullTransportBackupTask) msg.obj;
                (new Thread(task, "transport-backup")).start();
                break;
            }

            case MSG_RUN_RESTORE:
            {
                RestoreParams params = (RestoreParams)msg.obj;
                Slog.d(TAG, "MSG_RUN_RESTORE observer=" + params.observer);

                PerformUnifiedRestoreTask task = new PerformUnifiedRestoreTask(params.transport,
                        params.observer, params.monitor, params.token, params.pkgInfo,
                        params.pmToken, params.isSystemRestore, params.filterSet);

                synchronized (mPendingRestores) {
                    if (mIsRestoreInProgress) {
                        if (DEBUG) {
                            Slog.d(TAG, "Restore in progress, queueing.");
                        }
                        mPendingRestores.add(task);
                        // This task will be picked up and executed when the the currently running
                        // restore task finishes.
                    } else {
                        if (DEBUG) {
                            Slog.d(TAG, "Starting restore.");
                        }
                        mIsRestoreInProgress = true;
                        Message restoreMsg = obtainMessage(MSG_BACKUP_RESTORE_STEP, task);
                        sendMessage(restoreMsg);
                    }
                }
                break;
            }

            case MSG_RUN_ADB_RESTORE:
            {
                // TODO: refactor full restore to be a looper-based state machine
                // similar to normal backup/restore.
                AdbRestoreParams params = (AdbRestoreParams)msg.obj;
                PerformAdbRestoreTask task = new PerformAdbRestoreTask(params.fd,
                        params.curPassword, params.encryptPassword,
                        params.observer, params.latch);
                (new Thread(task, "adb-restore")).start();
                break;
            }

            case MSG_RUN_CLEAR:
            {
                ClearParams params = (ClearParams)msg.obj;
                (new PerformClearTask(params.transport, params.packageInfo)).run();
                break;
            }

            case MSG_RETRY_CLEAR:
            {
                // reenqueues if the transport remains unavailable
                ClearRetryParams params = (ClearRetryParams)msg.obj;
                clearBackupData(params.transportName, params.packageName);
                break;
            }

            case MSG_RETRY_INIT:
            {
                synchronized (mQueueLock) {
                    recordInitPendingLocked(msg.arg1 != 0, (String)msg.obj);
                    mAlarmManager.set(AlarmManager.RTC_WAKEUP, System.currentTimeMillis(),
                            mRunInitIntent);
                }
                break;
            }

            case MSG_RUN_GET_RESTORE_SETS:
            {
                // Like other async operations, this is entered with the wakelock held
                RestoreSet[] sets = null;
                RestoreGetSetsParams params = (RestoreGetSetsParams)msg.obj;
                try {
                    sets = params.transport.getAvailableRestoreSets();
                    // cache the result in the active session
                    synchronized (params.session) {
                        params.session.mRestoreSets = sets;
                    }
                    if (sets == null) EventLog.writeEvent(EventLogTags.RESTORE_TRANSPORT_FAILURE);
                } catch (Exception e) {
                    Slog.e(TAG, "Error from transport getting set list: " + e.getMessage());
                } finally {
                    if (params.observer != null) {
                        try {
                            params.observer.restoreSetsAvailable(sets);
                        } catch (RemoteException re) {
                            Slog.e(TAG, "Unable to report listing to observer");
                        } catch (Exception e) {
                            Slog.e(TAG, "Restore observer threw: " + e.getMessage());
                        }
                    }

                    // Done: reset the session timeout clock
                    removeMessages(MSG_RESTORE_SESSION_TIMEOUT);
                    sendEmptyMessageDelayed(MSG_RESTORE_SESSION_TIMEOUT, TIMEOUT_RESTORE_INTERVAL);

                    mWakelock.release();
                }
                break;
            }

            case MSG_BACKUP_OPERATION_TIMEOUT:
            case MSG_RESTORE_OPERATION_TIMEOUT:
            {
                Slog.d(TAG, "Timeout message received for token=" + Integer.toHexString(msg.arg1));
                handleCancel(msg.arg1, false);
                break;
            }

            case MSG_RESTORE_SESSION_TIMEOUT:
            {
                synchronized (BackupManagerService.this) {
                    if (mActiveRestoreSession != null) {
                        // Client app left the restore session dangling.  We know that it
                        // can't be in the middle of an actual restore operation because
                        // the timeout is suspended while a restore is in progress.  Clean
                        // up now.
                        Slog.w(TAG, "Restore session timed out; aborting");
                        mActiveRestoreSession.markTimedOut();
                        post(mActiveRestoreSession.new EndRestoreRunnable(
                                BackupManagerService.this, mActiveRestoreSession));
                    }
                }
                break;
            }

            case MSG_FULL_CONFIRMATION_TIMEOUT:
            {
                synchronized (mAdbBackupRestoreConfirmations) {
                    AdbParams params = mAdbBackupRestoreConfirmations.get(msg.arg1);
                    if (params != null) {
                        Slog.i(TAG, "Full backup/restore timed out waiting for user confirmation");

                        // Release the waiter; timeout == completion
                        signalAdbBackupRestoreCompletion(params);

                        // Remove the token from the set
                        mAdbBackupRestoreConfirmations.delete(msg.arg1);

                        // Report a timeout to the observer, if any
                        if (params.observer != null) {
                            try {
                                params.observer.onTimeout();
                            } catch (RemoteException e) {
                                /* don't care if the app has gone away */
                            }
                        }
                    } else {
                        Slog.d(TAG, "couldn't find params for token " + msg.arg1);
                    }
                }
                break;
            }

            case MSG_WIDGET_BROADCAST:
            {
                final Intent intent = (Intent) msg.obj;
                mContext.sendBroadcastAsUser(intent, UserHandle.SYSTEM);
                break;
            }

            case MSG_REQUEST_BACKUP:
            {
                BackupParams params = (BackupParams)msg.obj;
                if (MORE_DEBUG) {
                    Slog.d(TAG, "MSG_REQUEST_BACKUP observer=" + params.observer);
                }
                ArrayList<BackupRequest> kvQueue = new ArrayList<>();
                for (String packageName : params.kvPackages) {
                    kvQueue.add(new BackupRequest(packageName));
                }
                mBackupRunning = true;
                mWakelock.acquire();

                PerformBackupTask pbt = new PerformBackupTask(params.transport, params.dirName,
                        kvQueue, null, params.observer, params.monitor, params.fullPackages, true,
                        params.nonIncrementalBackup);
                Message pbtMessage = obtainMessage(MSG_BACKUP_RESTORE_STEP, pbt);
                sendMessage(pbtMessage);
                break;
            }

            case MSG_SCHEDULE_BACKUP_PACKAGE:
            {
                String pkgName = (String)msg.obj;
                if (MORE_DEBUG) {
                    Slog.d(TAG, "MSG_SCHEDULE_BACKUP_PACKAGE " + pkgName);
                }
                dataChangedImpl(pkgName);
                break;
            }
            }
        }
    }

    // ----- Debug-only backup operation trace -----
    void addBackupTrace(String s) {
        if (DEBUG_BACKUP_TRACE) {
            synchronized (mBackupTrace) {
                mBackupTrace.add(s);
            }
        }
    }

    void clearBackupTrace() {
        if (DEBUG_BACKUP_TRACE) {
            synchronized (mBackupTrace) {
                mBackupTrace.clear();
            }
        }
    }

    // ----- Main service implementation -----

    public BackupManagerService(Context context, Trampoline parent) {
        mContext = context;
        mPackageManager = context.getPackageManager();
        mPackageManagerBinder = AppGlobals.getPackageManager();
        mActivityManager = ActivityManager.getService();

        mAlarmManager = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
        mPowerManager = (PowerManager) context.getSystemService(Context.POWER_SERVICE);
        mStorageManager = IStorageManager.Stub.asInterface(ServiceManager.getService("mount"));

        mBackupManagerBinder = Trampoline.asInterface(parent.asBinder());

        // spin up the backup/restore handler thread
        mHandlerThread = new HandlerThread("backup", Process.THREAD_PRIORITY_BACKGROUND);
        mHandlerThread.start();
        mBackupHandler = new BackupHandler(mHandlerThread.getLooper());

        // Set up our bookkeeping
        final ContentResolver resolver = context.getContentResolver();
        mProvisioned = Settings.Global.getInt(resolver,
                Settings.Global.DEVICE_PROVISIONED, 0) != 0;
        mAutoRestore = Settings.Secure.getInt(resolver,
                Settings.Secure.BACKUP_AUTO_RESTORE, 1) != 0;

        mProvisionedObserver = new ProvisionedObserver(mBackupHandler);
        resolver.registerContentObserver(
                Settings.Global.getUriFor(Settings.Global.DEVICE_PROVISIONED),
                false, mProvisionedObserver);

        // If Encrypted file systems is enabled or disabled, this call will return the
        // correct directory.
        mBaseStateDir = new File(Environment.getDataDirectory(), "backup");
        mBaseStateDir.mkdirs();
        if (!SELinux.restorecon(mBaseStateDir)) {
            Slog.e(TAG, "SELinux restorecon failed on " + mBaseStateDir);
        }

        // This dir on /cache is managed directly in init.rc
        mDataDir = new File(Environment.getDownloadCacheDirectory(), "backup_stage");

        mPasswordVersion = 1;       // unless we hear otherwise
        mPasswordVersionFile = new File(mBaseStateDir, "pwversion");
        if (mPasswordVersionFile.exists()) {
            FileInputStream fin = null;
            DataInputStream in = null;
            try {
                fin = new FileInputStream(mPasswordVersionFile);
                in = new DataInputStream(fin);
                mPasswordVersion = in.readInt();
            } catch (IOException e) {
                Slog.e(TAG, "Unable to read backup pw version");
            } finally {
                try {
                    if (in != null) in.close();
                    if (fin != null) fin.close();
                } catch (IOException e) {
                    Slog.w(TAG, "Error closing pw version files");
                }
            }
        }

        mPasswordHashFile = new File(mBaseStateDir, "pwhash");
        if (mPasswordHashFile.exists()) {
            FileInputStream fin = null;
            DataInputStream in = null;
            try {
                fin = new FileInputStream(mPasswordHashFile);
                in = new DataInputStream(new BufferedInputStream(fin));
                // integer length of the salt array, followed by the salt,
                // then the hex pw hash string
                int saltLen = in.readInt();
                byte[] salt = new byte[saltLen];
                in.readFully(salt);
                mPasswordHash = in.readUTF();
                mPasswordSalt = salt;
            } catch (IOException e) {
                Slog.e(TAG, "Unable to read saved backup pw hash");
            } finally {
                try {
                    if (in != null) in.close();
                    if (fin != null) fin.close();
                } catch (IOException e) {
                    Slog.w(TAG, "Unable to close streams");
                }
            }
        }

        // Alarm receivers for scheduled backups & initialization operations
        mRunBackupReceiver = new RunBackupReceiver();
        IntentFilter filter = new IntentFilter();
        filter.addAction(RUN_BACKUP_ACTION);
        context.registerReceiver(mRunBackupReceiver, filter,
                android.Manifest.permission.BACKUP, null);

        mRunInitReceiver = new RunInitializeReceiver();
        filter = new IntentFilter();
        filter.addAction(RUN_INITIALIZE_ACTION);
        context.registerReceiver(mRunInitReceiver, filter,
                android.Manifest.permission.BACKUP, null);

        Intent backupIntent = new Intent(RUN_BACKUP_ACTION);
        backupIntent.addFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY);
        mRunBackupIntent = PendingIntent.getBroadcast(context, MSG_RUN_BACKUP, backupIntent, 0);

        Intent initIntent = new Intent(RUN_INITIALIZE_ACTION);
        backupIntent.addFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY);
        mRunInitIntent = PendingIntent.getBroadcast(context, 0, initIntent, 0);

        // Set up the backup-request journaling
        mJournalDir = new File(mBaseStateDir, "pending");
        mJournalDir.mkdirs();   // creates mBaseStateDir along the way
        mJournal = null;        // will be created on first use

        // Set up the various sorts of package tracking we do
        mFullBackupScheduleFile = new File(mBaseStateDir, "fb-schedule");
        initPackageTracking();

        // Build our mapping of uid to backup client services.  This implicitly
        // schedules a backup pass on the Package Manager metadata the first
        // time anything needs to be backed up.
        synchronized (mBackupParticipants) {
            addPackageParticipantsLocked(null);
        }

        // Set up our transport options and initialize the default transport
        // TODO: Don't create transports that we don't need to?
        SystemConfig systemConfig = SystemConfig.getInstance();
        Set<ComponentName> transportWhitelist = systemConfig.getBackupTransportWhitelist();

        String transport = Settings.Secure.getString(context.getContentResolver(),
                Settings.Secure.BACKUP_TRANSPORT);
        if (TextUtils.isEmpty(transport)) {
            transport = null;
        }
        String currentTransport = transport;
        if (DEBUG) Slog.v(TAG, "Starting with transport " + currentTransport);

        mTransportManager = new TransportManager(context, transportWhitelist, currentTransport,
                mTransportBoundListener, mHandlerThread.getLooper());
        mTransportManager.registerAllTransports();

        // Now that we know about valid backup participants, parse any
        // leftover journal files into the pending backup set
        mBackupHandler.post(() -> parseLeftoverJournals());

        // Power management
        mWakelock = mPowerManager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, "*backup*");
    }

    private class RunBackupReceiver extends BroadcastReceiver {
        public void onReceive(Context context, Intent intent) {
            if (RUN_BACKUP_ACTION.equals(intent.getAction())) {
                synchronized (mQueueLock) {
                    if (mPendingInits.size() > 0) {
                        // If there are pending init operations, we process those
                        // and then settle into the usual periodic backup schedule.
                        if (MORE_DEBUG) Slog.v(TAG, "Init pending at scheduled backup");
                        try {
                            mAlarmManager.cancel(mRunInitIntent);
                            mRunInitIntent.send();
                        } catch (PendingIntent.CanceledException ce) {
                            Slog.e(TAG, "Run init intent cancelled");
                            // can't really do more than bail here
                        }
                    } else {
                        // Don't run backups now if we're disabled or not yet
                        // fully set up.
                        if (mEnabled && mProvisioned) {
                            if (!mBackupRunning) {
                                if (DEBUG) Slog.v(TAG, "Running a backup pass");

                                // Acquire the wakelock and pass it to the backup thread.  it will
                                // be released once backup concludes.
                                mBackupRunning = true;
                                mWakelock.acquire();

                                Message msg = mBackupHandler.obtainMessage(MSG_RUN_BACKUP);
                                mBackupHandler.sendMessage(msg);
                            } else {
                                Slog.i(TAG, "Backup time but one already running");
                            }
                        } else {
                            Slog.w(TAG, "Backup pass but e=" + mEnabled + " p=" + mProvisioned);
                        }
                    }
                }
            }
        }
    }

    private class RunInitializeReceiver extends BroadcastReceiver {
        public void onReceive(Context context, Intent intent) {
            if (RUN_INITIALIZE_ACTION.equals(intent.getAction())) {
                // Snapshot the pending-init queue and work on that
                synchronized (mQueueLock) {
                    String[] queue = mPendingInits.toArray(new String[mPendingInits.size()]);
                    mPendingInits.clear();

                    // Acquire the wakelock and pass it to the init thread.  it will
                    // be released once init concludes.
                    mWakelock.acquire();
                    mBackupHandler.post(new PerformInitializeTask(queue, null));
                }
            }
        }
    }

    private void initPackageTracking() {
        if (MORE_DEBUG) Slog.v(TAG, "` tracking");

        // Remember our ancestral dataset
        mTokenFile = new File(mBaseStateDir, "ancestral");
        try (DataInputStream tokenStream = new DataInputStream(new BufferedInputStream(
                new FileInputStream(mTokenFile)))) {
            int version = tokenStream.readInt();
            if (version == CURRENT_ANCESTRAL_RECORD_VERSION) {
                mAncestralToken = tokenStream.readLong();
                mCurrentToken = tokenStream.readLong();

                int numPackages = tokenStream.readInt();
                if (numPackages >= 0) {
                    mAncestralPackages = new HashSet<>();
                    for (int i = 0; i < numPackages; i++) {
                        String pkgName = tokenStream.readUTF();
                        mAncestralPackages.add(pkgName);
                    }
                }
            }
        } catch (FileNotFoundException fnf) {
            // Probably innocuous
            Slog.v(TAG, "No ancestral data");
        } catch (IOException e) {
            Slog.w(TAG, "Unable to read token file", e);
        }

        // Keep a log of what apps we've ever backed up.  Because we might have
        // rebooted in the middle of an operation that was removing something from
        // this log, we sanity-check its contents here and reconstruct it.
        mEverStored = new File(mBaseStateDir, "processed");
        File tempProcessedFile = new File(mBaseStateDir, "processed.new");

        // If we were in the middle of removing something from the ever-backed-up
        // file, there might be a transient "processed.new" file still present.
        // Ignore it -- we'll validate "processed" against the current package set.
        if (tempProcessedFile.exists()) {
            tempProcessedFile.delete();
        }

        // If there are previous contents, parse them out then start a new
        // file to continue the recordkeeping.
        if (mEverStored.exists()) {
            DataOutputStream temp = null;
            DataInputStream in = null;

            try {
                temp = new DataOutputStream(new BufferedOutputStream(new FileOutputStream(
                        tempProcessedFile)));
                in = new DataInputStream(new BufferedInputStream(new FileInputStream(mEverStored)));

                // Loop until we hit EOF
                while (true) {
                    String pkg = in.readUTF();
                    try {
                        // is this package still present?
                        mPackageManager.getPackageInfo(pkg, 0);
                        // if we get here then yes it is; remember it
                        mEverStoredApps.add(pkg);
                        temp.writeUTF(pkg);
                        if (MORE_DEBUG) Slog.v(TAG, "   + " + pkg);
                    } catch (NameNotFoundException e) {
                        // nope, this package was uninstalled; don't include it
                        if (MORE_DEBUG) Slog.v(TAG, "   - " + pkg);
                    }
                }
            } catch (EOFException e) {
                // Once we've rewritten the backup history log, atomically replace the
                // old one with the new one then reopen the file for continuing use.
                if (!tempProcessedFile.renameTo(mEverStored)) {
                    Slog.e(TAG, "Error renaming " + tempProcessedFile + " to " + mEverStored);
                }
            } catch (IOException e) {
                Slog.e(TAG, "Error in processed file", e);
            } finally {
                try { if (temp != null) temp.close(); } catch (IOException e) {}
                try { if (in != null) in.close(); } catch (IOException e) {}
            }
        }

        synchronized (mQueueLock) {
            // Resume the full-data backup queue
            mFullBackupQueue = readFullBackupSchedule();
        }

        // Register for broadcasts about package install, etc., so we can
        // update the provider list.
        IntentFilter filter = new IntentFilter();
        filter.addAction(Intent.ACTION_PACKAGE_ADDED);
        filter.addAction(Intent.ACTION_PACKAGE_REMOVED);
        filter.addAction(Intent.ACTION_PACKAGE_CHANGED);
        filter.addDataScheme("package");
        mContext.registerReceiver(mBroadcastReceiver, filter);
        // Register for events related to sdcard installation.
        IntentFilter sdFilter = new IntentFilter();
        sdFilter.addAction(Intent.ACTION_EXTERNAL_APPLICATIONS_AVAILABLE);
        sdFilter.addAction(Intent.ACTION_EXTERNAL_APPLICATIONS_UNAVAILABLE);
        mContext.registerReceiver(mBroadcastReceiver, sdFilter);
    }

    private ArrayList<FullBackupEntry> readFullBackupSchedule() {
        boolean changed = false;
        ArrayList<FullBackupEntry> schedule = null;
        List<PackageInfo> apps =
                PackageManagerBackupAgent.getStorableApplications(mPackageManager);

        if (mFullBackupScheduleFile.exists()) {
            FileInputStream fstream = null;
            BufferedInputStream bufStream = null;
            DataInputStream in = null;
            try {
                fstream = new FileInputStream(mFullBackupScheduleFile);
                bufStream = new BufferedInputStream(fstream);
                in = new DataInputStream(bufStream);

                int version = in.readInt();
                if (version != SCHEDULE_FILE_VERSION) {
                    Slog.e(TAG, "Unknown backup schedule version " + version);
                    return null;
                }

                final int N = in.readInt();
                schedule = new ArrayList<FullBackupEntry>(N);

                // HashSet instead of ArraySet specifically because we want the eventual
                // lookups against O(hundreds) of entries to be as fast as possible, and
                // we discard the set immediately after the scan so the extra memory
                // overhead is transient.
                HashSet<String> foundApps = new HashSet<String>(N);

                for (int i = 0; i < N; i++) {
                    String pkgName = in.readUTF();
                    long lastBackup = in.readLong();
                    foundApps.add(pkgName); // all apps that we've addressed already
                    try {
                        PackageInfo pkg = mPackageManager.getPackageInfo(pkgName, 0);
                        if (appGetsFullBackup(pkg)
                                && appIsEligibleForBackup(pkg.applicationInfo, mPackageManager)) {
                            schedule.add(new FullBackupEntry(pkgName, lastBackup));
                        } else {
                            if (DEBUG) {
                                Slog.i(TAG, "Package " + pkgName
                                        + " no longer eligible for full backup");
                            }
                        }
                    } catch (NameNotFoundException e) {
                        if (DEBUG) {
                            Slog.i(TAG, "Package " + pkgName
                                    + " not installed; dropping from full backup");
                        }
                    }
                }

                // New apps can arrive "out of band" via OTA and similar, so we also need to
                // scan to make sure that we're tracking all full-backup candidates properly
                for (PackageInfo app : apps) {
                    if (appGetsFullBackup(app)
                            && appIsEligibleForBackup(app.applicationInfo, mPackageManager)) {
                        if (!foundApps.contains(app.packageName)) {
                            if (MORE_DEBUG) {
                                Slog.i(TAG, "New full backup app " + app.packageName + " found");
                            }
                            schedule.add(new FullBackupEntry(app.packageName, 0));
                            changed = true;
                        }
                    }
                }

                Collections.sort(schedule);
            } catch (Exception e) {
                Slog.e(TAG, "Unable to read backup schedule", e);
                mFullBackupScheduleFile.delete();
                schedule = null;
            } finally {
                IoUtils.closeQuietly(in);
                IoUtils.closeQuietly(bufStream);
                IoUtils.closeQuietly(fstream);
            }
        }

        if (schedule == null) {
            // no prior queue record, or unable to read it.  Set up the queue
            // from scratch.
            changed = true;
            schedule = new ArrayList<FullBackupEntry>(apps.size());
            for (PackageInfo info : apps) {
                if (appGetsFullBackup(info)
                        && appIsEligibleForBackup(info.applicationInfo, mPackageManager)) {
                    schedule.add(new FullBackupEntry(info.packageName, 0));
                }
            }
        }

        if (changed) {
            writeFullBackupScheduleAsync();
        }
        return schedule;
    }

    Runnable mFullBackupScheduleWriter = new Runnable() {
        @Override public void run() {
            synchronized (mQueueLock) {
                try {
                    ByteArrayOutputStream bufStream = new ByteArrayOutputStream(4096);
                    DataOutputStream bufOut = new DataOutputStream(bufStream);
                    bufOut.writeInt(SCHEDULE_FILE_VERSION);

                    // version 1:
                    //
                    // [int] # of packages in the queue = N
                    // N * {
                    //     [utf8] package name
                    //     [long] last backup time for this package
                    //     }
                    int N = mFullBackupQueue.size();
                    bufOut.writeInt(N);

                    for (int i = 0; i < N; i++) {
                        FullBackupEntry entry = mFullBackupQueue.get(i);
                        bufOut.writeUTF(entry.packageName);
                        bufOut.writeLong(entry.lastBackup);
                    }
                    bufOut.flush();

                    AtomicFile af = new AtomicFile(mFullBackupScheduleFile);
                    FileOutputStream out = af.startWrite();
                    out.write(bufStream.toByteArray());
                    af.finishWrite(out);
                } catch (Exception e) {
                    Slog.e(TAG, "Unable to write backup schedule!", e);
                }
            }
        }
    };

    private void writeFullBackupScheduleAsync() {
        mBackupHandler.removeCallbacks(mFullBackupScheduleWriter);
        mBackupHandler.post(mFullBackupScheduleWriter);
    }

    private void parseLeftoverJournals() {
        for (File f : mJournalDir.listFiles()) {
            if (mJournal == null || f.compareTo(mJournal) != 0) {
                // This isn't the current journal, so it must be a leftover.  Read
                // out the package names mentioned there and schedule them for
                // backup.
                DataInputStream in = null;
                try {
                    Slog.i(TAG, "Found stale backup journal, scheduling");
                    // Journals will tend to be on the order of a few kilobytes(around 4k), hence,
                    // setting the buffer size to 8192.
                    InputStream bufferedInputStream = new BufferedInputStream(
                            new FileInputStream(f), 8192);
                    in = new DataInputStream(bufferedInputStream);
                    while (true) {
                        String packageName = in.readUTF();
                        if (MORE_DEBUG) Slog.i(TAG, "  " + packageName);
                        dataChangedImpl(packageName);
                    }
                } catch (EOFException e) {
                    // no more data; we're done
                } catch (Exception e) {
                    Slog.e(TAG, "Can't read " + f, e);
                } finally {
                    // close/delete the file
                    try { if (in != null) in.close(); } catch (IOException e) {}
                    f.delete();
                }
            }
        }
    }

    private SecretKey buildPasswordKey(String algorithm, String pw, byte[] salt, int rounds) {
        return buildCharArrayKey(algorithm, pw.toCharArray(), salt, rounds);
    }

    private SecretKey buildCharArrayKey(String algorithm, char[] pwArray, byte[] salt, int rounds) {
        try {
            SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(algorithm);
            KeySpec ks = new PBEKeySpec(pwArray, salt, rounds, PBKDF2_KEY_SIZE);
            return keyFactory.generateSecret(ks);
        } catch (InvalidKeySpecException e) {
            Slog.e(TAG, "Invalid key spec for PBKDF2!");
        } catch (NoSuchAlgorithmException e) {
            Slog.e(TAG, "PBKDF2 unavailable!");
        }
        return null;
    }

    private String buildPasswordHash(String algorithm, String pw, byte[] salt, int rounds) {
        SecretKey key = buildPasswordKey(algorithm, pw, salt, rounds);
        if (key != null) {
            return byteArrayToHex(key.getEncoded());
        }
        return null;
    }

    private String byteArrayToHex(byte[] data) {
        StringBuilder buf = new StringBuilder(data.length * 2);
        for (int i = 0; i < data.length; i++) {
            buf.append(Byte.toHexString(data[i], true));
        }
        return buf.toString();
    }

    private byte[] hexToByteArray(String digits) {
        final int bytes = digits.length() / 2;
        if (2*bytes != digits.length()) {
            throw new IllegalArgumentException("Hex string must have an even number of digits");
        }

        byte[] result = new byte[bytes];
        for (int i = 0; i < digits.length(); i += 2) {
            result[i/2] = (byte) Integer.parseInt(digits.substring(i, i+2), 16);
        }
        return result;
    }

    private byte[] makeKeyChecksum(String algorithm, byte[] pwBytes, byte[] salt, int rounds) {
        char[] mkAsChar = new char[pwBytes.length];
        for (int i = 0; i < pwBytes.length; i++) {
            mkAsChar[i] = (char) pwBytes[i];
        }

        Key checksum = buildCharArrayKey(algorithm, mkAsChar, salt, rounds);
        return checksum.getEncoded();
    }

    // Used for generating random salts or passwords
    private byte[] randomBytes(int bits) {
        byte[] array = new byte[bits / 8];
        mRng.nextBytes(array);
        return array;
    }

    boolean passwordMatchesSaved(String algorithm, String candidatePw, int rounds) {
        if (mPasswordHash == null) {
            // no current password case -- require that 'currentPw' be null or empty
            if (candidatePw == null || "".equals(candidatePw)) {
                return true;
            } // else the non-empty candidate does not match the empty stored pw
        } else {
            // hash the stated current pw and compare to the stored one
            if (candidatePw != null && candidatePw.length() > 0) {
                String currentPwHash = buildPasswordHash(algorithm, candidatePw, mPasswordSalt, rounds);
                if (mPasswordHash.equalsIgnoreCase(currentPwHash)) {
                    // candidate hash matches the stored hash -- the password matches
                    return true;
                }
            } // else the stored pw is nonempty but the candidate is empty; no match
        }
        return false;
    }

    @Override
    public boolean setBackupPassword(String currentPw, String newPw) {
        mContext.enforceCallingOrSelfPermission(android.Manifest.permission.BACKUP,
                "setBackupPassword");

        // When processing v1 passwords we may need to try two different PBKDF2 checksum regimes
        final boolean pbkdf2Fallback = (mPasswordVersion < BACKUP_PW_FILE_VERSION);

        // If the supplied pw doesn't hash to the the saved one, fail.  The password
        // might be caught in the legacy crypto mismatch; verify that too.
        if (!passwordMatchesSaved(PBKDF_CURRENT, currentPw, PBKDF2_HASH_ROUNDS)
                && !(pbkdf2Fallback && passwordMatchesSaved(PBKDF_FALLBACK,
                        currentPw, PBKDF2_HASH_ROUNDS))) {
            return false;
        }

        // Snap up to current on the pw file version
        mPasswordVersion = BACKUP_PW_FILE_VERSION;
        FileOutputStream pwFout = null;
        DataOutputStream pwOut = null;
        try {
            pwFout = new FileOutputStream(mPasswordVersionFile);
            pwOut = new DataOutputStream(pwFout);
            pwOut.writeInt(mPasswordVersion);
        } catch (IOException e) {
            Slog.e(TAG, "Unable to write backup pw version; password not changed");
            return false;
        } finally {
            try {
                if (pwOut != null) pwOut.close();
                if (pwFout != null) pwFout.close();
            } catch (IOException e) {
                Slog.w(TAG, "Unable to close pw version record");
            }
        }

        // Clearing the password is okay
        if (newPw == null || newPw.isEmpty()) {
            if (mPasswordHashFile.exists()) {
                if (!mPasswordHashFile.delete()) {
                    // Unable to delete the old pw file, so fail
                    Slog.e(TAG, "Unable to clear backup password");
                    return false;
                }
            }
            mPasswordHash = null;
            mPasswordSalt = null;
            return true;
        }

        try {
            // Okay, build the hash of the new backup password
            byte[] salt = randomBytes(PBKDF2_SALT_SIZE);
            String newPwHash = buildPasswordHash(PBKDF_CURRENT, newPw, salt, PBKDF2_HASH_ROUNDS);

            OutputStream pwf = null, buffer = null;
            DataOutputStream out = null;
            try {
                pwf = new FileOutputStream(mPasswordHashFile);
                buffer = new BufferedOutputStream(pwf);
                out = new DataOutputStream(buffer);
                // integer length of the salt array, followed by the salt,
                // then the hex pw hash string
                out.writeInt(salt.length);
                out.write(salt);
                out.writeUTF(newPwHash);
                out.flush();
                mPasswordHash = newPwHash;
                mPasswordSalt = salt;
                return true;
            } finally {
                if (out != null) out.close();
                if (buffer != null) buffer.close();
                if (pwf != null) pwf.close();
            }
        } catch (IOException e) {
            Slog.e(TAG, "Unable to set backup password");
        }
        return false;
    }

    @Override
    public boolean hasBackupPassword() {
        mContext.enforceCallingOrSelfPermission(android.Manifest.permission.BACKUP,
                "hasBackupPassword");

        return mPasswordHash != null && mPasswordHash.length() > 0;
    }

    private boolean backupPasswordMatches(String currentPw) {
        if (hasBackupPassword()) {
            final boolean pbkdf2Fallback = (mPasswordVersion < BACKUP_PW_FILE_VERSION);
            if (!passwordMatchesSaved(PBKDF_CURRENT, currentPw, PBKDF2_HASH_ROUNDS)
                    && !(pbkdf2Fallback && passwordMatchesSaved(PBKDF_FALLBACK,
                            currentPw, PBKDF2_HASH_ROUNDS))) {
                if (DEBUG) Slog.w(TAG, "Backup password mismatch; aborting");
                return false;
            }
        }
        return true;
    }

    // Maintain persistent state around whether need to do an initialize operation.
    // Must be called with the queue lock held.
    void recordInitPendingLocked(boolean isPending, String transportName) {
        if (MORE_DEBUG) Slog.i(TAG, "recordInitPendingLocked: " + isPending
                + " on transport " + transportName);
        mBackupHandler.removeMessages(MSG_RETRY_INIT);

        try {
            IBackupTransport transport = mTransportManager.getTransportBinder(transportName);
            if (transport != null) {
                String transportDirName = transport.transportDirName();
                File stateDir = new File(mBaseStateDir, transportDirName);
                File initPendingFile = new File(stateDir, INIT_SENTINEL_FILE_NAME);

                if (isPending) {
                    // We need an init before we can proceed with sending backup data.
                    // Record that with an entry in our set of pending inits, as well as
                    // journaling it via creation of a sentinel file.
                    mPendingInits.add(transportName);
                    try {
                        (new FileOutputStream(initPendingFile)).close();
                    } catch (IOException ioe) {
                        // Something is badly wrong with our permissions; just try to move on
                    }
                } else {
                    // No more initialization needed; wipe the journal and reset our state.
                    initPendingFile.delete();
                    mPendingInits.remove(transportName);
                }
                return; // done; don't fall through to the error case
            }
        } catch (Exception e) {
            // transport threw when asked its name; fall through to the lookup-failed case
            Slog.e(TAG, "Transport " + transportName + " failed to report name: "
                    + e.getMessage());
        }

        // The named transport doesn't exist or threw.  This operation is
        // important, so we record the need for a an init and post a message
        // to retry the init later.
        if (isPending) {
            mPendingInits.add(transportName);
            mBackupHandler.sendMessageDelayed(
                    mBackupHandler.obtainMessage(MSG_RETRY_INIT,
                            (isPending ? 1 : 0),
                            0,
                            transportName),
                    TRANSPORT_RETRY_INTERVAL);
        }
    }

    // Reset all of our bookkeeping, in response to having been told that
    // the backend data has been wiped [due to idle expiry, for example],
    // so we must re-upload all saved settings.
    void resetBackupState(File stateFileDir) {
        synchronized (mQueueLock) {
            // Wipe the "what we've ever backed up" tracking
            mEverStoredApps.clear();
            mEverStored.delete();

            mCurrentToken = 0;
            writeRestoreTokens();

            // Remove all the state files
            for (File sf : stateFileDir.listFiles()) {
                // ... but don't touch the needs-init sentinel
                if (!sf.getName().equals(INIT_SENTINEL_FILE_NAME)) {
                    sf.delete();
                }
            }
        }

        // Enqueue a new backup of every participant
        synchronized (mBackupParticipants) {
            final int N = mBackupParticipants.size();
            for (int i=0; i<N; i++) {
                HashSet<String> participants = mBackupParticipants.valueAt(i);
                if (participants != null) {
                    for (String packageName : participants) {
                        dataChangedImpl(packageName);
                    }
                }
            }
        }
    }

    private TransportManager.TransportBoundListener mTransportBoundListener =
            new TransportManager.TransportBoundListener() {
        @Override
        public boolean onTransportBound(IBackupTransport transport) {
            // If the init sentinel file exists, we need to be sure to perform the init
            // as soon as practical.  We also create the state directory at registration
            // time to ensure it's present from the outset.
            String name = null;
            try {
                name = transport.name();
                String transportDirName = transport.transportDirName();
                File stateDir = new File(mBaseStateDir, transportDirName);
                stateDir.mkdirs();

                File initSentinel = new File(stateDir, INIT_SENTINEL_FILE_NAME);
                if (initSentinel.exists()) {
                    synchronized (mQueueLock) {
                        mPendingInits.add(name);

                        // TODO: pick a better starting time than now + 1 minute
                        long delay = 1000 * 60; // one minute, in milliseconds
                        mAlarmManager.set(AlarmManager.RTC_WAKEUP,
                                System.currentTimeMillis() + delay, mRunInitIntent);
                    }
                }
                return true;
            } catch (Exception e) {
                // the transport threw when asked its file naming prefs; declare it invalid
                Slog.w(TAG, "Failed to regiser transport: " + name);
                return false;
            }
        }
    };

    // ----- Track installation/removal of packages -----
    BroadcastReceiver mBroadcastReceiver = new BroadcastReceiver() {
        public void onReceive(Context context, Intent intent) {
            if (MORE_DEBUG) Slog.d(TAG, "Received broadcast " + intent);

            String action = intent.getAction();
            boolean replacing = false;
            boolean added = false;
            boolean changed = false;
            Bundle extras = intent.getExtras();
            String pkgList[] = null;
            if (Intent.ACTION_PACKAGE_ADDED.equals(action) ||
                    Intent.ACTION_PACKAGE_REMOVED.equals(action) ||
                    Intent.ACTION_PACKAGE_CHANGED.equals(action)) {
                Uri uri = intent.getData();
                if (uri == null) {
                    return;
                }
                String pkgName = uri.getSchemeSpecificPart();
                if (pkgName != null) {
                    pkgList = new String[] { pkgName };
                }
                changed = Intent.ACTION_PACKAGE_CHANGED.equals(action);

                // At package-changed we only care about looking at new transport states
                if (changed) {
                    String[] components =
                            intent.getStringArrayExtra(Intent.EXTRA_CHANGED_COMPONENT_NAME_LIST);

                    if (MORE_DEBUG) {
                        Slog.i(TAG, "Package " + pkgName + " changed; rechecking");
                        for (int i = 0; i < components.length; i++) {
                            Slog.i(TAG, "   * " + components[i]);
                        }
                    }

                    mTransportManager.onPackageChanged(pkgName, components);
                    return; // nothing more to do in the PACKAGE_CHANGED case
                }

                added = Intent.ACTION_PACKAGE_ADDED.equals(action);
                replacing = extras.getBoolean(Intent.EXTRA_REPLACING, false);
            } else if (Intent.ACTION_EXTERNAL_APPLICATIONS_AVAILABLE.equals(action)) {
                added = true;
                pkgList = intent.getStringArrayExtra(Intent.EXTRA_CHANGED_PACKAGE_LIST);
            } else if (Intent.ACTION_EXTERNAL_APPLICATIONS_UNAVAILABLE.equals(action)) {
                added = false;
                pkgList = intent.getStringArrayExtra(Intent.EXTRA_CHANGED_PACKAGE_LIST);
            }

            if (pkgList == null || pkgList.length == 0) {
                return;
            }

            final int uid = extras.getInt(Intent.EXTRA_UID);
            if (added) {
                synchronized (mBackupParticipants) {
                    if (replacing) {
                        // This is the package-replaced case; we just remove the entry
                        // under the old uid and fall through to re-add.  If an app
                        // just added key/value backup participation, this picks it up
                        // as a known participant.
                        removePackageParticipantsLocked(pkgList, uid);
                    }
                    addPackageParticipantsLocked(pkgList);
                }
                // If they're full-backup candidates, add them there instead
                final long now = System.currentTimeMillis();
                for (String packageName : pkgList) {
                    try {
                        PackageInfo app = mPackageManager.getPackageInfo(packageName, 0);
                        if (appGetsFullBackup(app)
                                && appIsEligibleForBackup(app.applicationInfo, mPackageManager)) {
                            enqueueFullBackup(packageName, now);
                            scheduleNextFullBackupJob(0);
                        } else {
                            // The app might have just transitioned out of full-data into
                            // doing key/value backups, or might have just disabled backups
                            // entirely.  Make sure it is no longer in the full-data queue.
                            synchronized (mQueueLock) {
                                dequeueFullBackupLocked(packageName);
                            }
                            writeFullBackupScheduleAsync();
                        }

                        mTransportManager.onPackageAdded(packageName);

                    } catch (NameNotFoundException e) {
                        // doesn't really exist; ignore it
                        if (DEBUG) {
                            Slog.w(TAG, "Can't resolve new app " + packageName);
                        }
                    }
                }

                // Whenever a package is added or updated we need to update
                // the package metadata bookkeeping.
                dataChangedImpl(PACKAGE_MANAGER_SENTINEL);
            } else {
                if (replacing) {
                    // The package is being updated.  We'll receive a PACKAGE_ADDED shortly.
                } else {
                    // Outright removal.  In the full-data case, the app will be dropped
                    // from the queue when its (now obsolete) name comes up again for
                    // backup.
                    synchronized (mBackupParticipants) {
                        removePackageParticipantsLocked(pkgList, uid);
                    }
                }
                for (String pkgName : pkgList) {
                    mTransportManager.onPackageRemoved(pkgName);
                }
            }
        }
    };

    // Add the backup agents in the given packages to our set of known backup participants.
    // If 'packageNames' is null, adds all backup agents in the whole system.
    void addPackageParticipantsLocked(String[] packageNames) {
        // Look for apps that define the android:backupAgent attribute
        List<PackageInfo> targetApps = allAgentPackages();
        if (packageNames != null) {
            if (MORE_DEBUG) Slog.v(TAG, "addPackageParticipantsLocked: #" + packageNames.length);
            for (String packageName : packageNames) {
                addPackageParticipantsLockedInner(packageName, targetApps);
            }
        } else {
            if (MORE_DEBUG) Slog.v(TAG, "addPackageParticipantsLocked: all");
            addPackageParticipantsLockedInner(null, targetApps);
        }
    }

    private void addPackageParticipantsLockedInner(String packageName,
            List<PackageInfo> targetPkgs) {
        if (MORE_DEBUG) {
            Slog.v(TAG, "Examining " + packageName + " for backup agent");
        }

        for (PackageInfo pkg : targetPkgs) {
            if (packageName == null || pkg.packageName.equals(packageName)) {
                int uid = pkg.applicationInfo.uid;
                HashSet<String> set = mBackupParticipants.get(uid);
                if (set == null) {
                    set = new HashSet<>();
                    mBackupParticipants.put(uid, set);
                }
                set.add(pkg.packageName);
                if (MORE_DEBUG) Slog.v(TAG, "Agent found; added");

                // Schedule a backup for it on general principles
                if (MORE_DEBUG) Slog.i(TAG, "Scheduling backup for new app " + pkg.packageName);
                Message msg = mBackupHandler
                        .obtainMessage(MSG_SCHEDULE_BACKUP_PACKAGE, pkg.packageName);
                mBackupHandler.sendMessage(msg);
            }
        }
    }

    // Remove the given packages' entries from our known active set.
    void removePackageParticipantsLocked(String[] packageNames, int oldUid) {
        if (packageNames == null) {
            Slog.w(TAG, "removePackageParticipants with null list");
            return;
        }

        if (MORE_DEBUG) Slog.v(TAG, "removePackageParticipantsLocked: uid=" + oldUid
                + " #" + packageNames.length);
        for (String pkg : packageNames) {
            // Known previous UID, so we know which package set to check
            HashSet<String> set = mBackupParticipants.get(oldUid);
            if (set != null && set.contains(pkg)) {
                removePackageFromSetLocked(set, pkg);
                if (set.isEmpty()) {
                    if (MORE_DEBUG) Slog.v(TAG, "  last one of this uid; purging set");
                    mBackupParticipants.remove(oldUid);
                }
            }
        }
    }

    private void removePackageFromSetLocked(final HashSet<String> set,
            final String packageName) {
        if (set.contains(packageName)) {
            // Found it.  Remove this one package from the bookkeeping, and
            // if it's the last participating app under this uid we drop the
            // (now-empty) set as well.
            // Note that we deliberately leave it 'known' in the "ever backed up"
            // bookkeeping so that its current-dataset data will be retrieved
            // if the app is subsequently reinstalled
            if (MORE_DEBUG) Slog.v(TAG, "  removing participant " + packageName);
            set.remove(packageName);
            mPendingBackups.remove(packageName);
        }
    }

    // Returns the set of all applications that define an android:backupAgent attribute
    List<PackageInfo> allAgentPackages() {
        // !!! TODO: cache this and regenerate only when necessary
        int flags = PackageManager.GET_SIGNATURES;
        List<PackageInfo> packages = mPackageManager.getInstalledPackages(flags);
        int N = packages.size();
        for (int a = N-1; a >= 0; a--) {
            PackageInfo pkg = packages.get(a);
            try {
                ApplicationInfo app = pkg.applicationInfo;
                if (((app.flags&ApplicationInfo.FLAG_ALLOW_BACKUP) == 0)
                        || app.backupAgentName == null
                        || (app.flags&ApplicationInfo.FLAG_FULL_BACKUP_ONLY) != 0) {
                    packages.remove(a);
                }
                else {
                    // we will need the shared library path, so look that up and store it here.
                    // This is used implicitly when we pass the PackageInfo object off to
                    // the Activity Manager to launch the app for backup/restore purposes.
                    app = mPackageManager.getApplicationInfo(pkg.packageName,
                            PackageManager.GET_SHARED_LIBRARY_FILES);
                    pkg.applicationInfo.sharedLibraryFiles = app.sharedLibraryFiles;
                }
            } catch (NameNotFoundException e) {
                packages.remove(a);
            }
        }
        return packages;
    }

    // Called from the backup tasks: record that the given app has been successfully
    // backed up at least once.  This includes both key/value and full-data backups
    // through the transport.
    void logBackupComplete(String packageName) {
        if (packageName.equals(PACKAGE_MANAGER_SENTINEL)) return;

        synchronized (mEverStoredApps) {
            if (!mEverStoredApps.add(packageName)) return;

            RandomAccessFile out = null;
            try {
                out = new RandomAccessFile(mEverStored, "rws");
                out.seek(out.length());
                out.writeUTF(packageName);
            } catch (IOException e) {
                Slog.e(TAG, "Can't log backup of " + packageName + " to " + mEverStored);
            } finally {
                try { if (out != null) out.close(); } catch (IOException e) {}
            }
        }
    }

    // Remove our awareness of having ever backed up the given package
    void removeEverBackedUp(String packageName) {
        if (DEBUG) Slog.v(TAG, "Removing backed-up knowledge of " + packageName);
        if (MORE_DEBUG) Slog.v(TAG, "New set:");

        synchronized (mEverStoredApps) {
            // Rewrite the file and rename to overwrite.  If we reboot in the middle,
            // we'll recognize on initialization time that the package no longer
            // exists and fix it up then.
            File tempKnownFile = new File(mBaseStateDir, "processed.new");
            RandomAccessFile known = null;
            try {
                known = new RandomAccessFile(tempKnownFile, "rws");
                mEverStoredApps.remove(packageName);
                for (String s : mEverStoredApps) {
                    known.writeUTF(s);
                    if (MORE_DEBUG) Slog.v(TAG, "    " + s);
                }
                known.close();
                known = null;
                if (!tempKnownFile.renameTo(mEverStored)) {
                    throw new IOException("Can't rename " + tempKnownFile + " to " + mEverStored);
                }
            } catch (IOException e) {
                // Bad: we couldn't create the new copy.  For safety's sake we
                // abandon the whole process and remove all what's-backed-up
                // state entirely, meaning we'll force a backup pass for every
                // participant on the next boot or [re]install.
                Slog.w(TAG, "Error rewriting " + mEverStored, e);
                mEverStoredApps.clear();
                tempKnownFile.delete();
                mEverStored.delete();
            } finally {
                try { if (known != null) known.close(); } catch (IOException e) {}
            }
        }
    }

    // Persistently record the current and ancestral backup tokens as well
    // as the set of packages with data [supposedly] available in the
    // ancestral dataset.
    void writeRestoreTokens() {
        try {
            RandomAccessFile af = new RandomAccessFile(mTokenFile, "rwd");

            // First, the version number of this record, for futureproofing
            af.writeInt(CURRENT_ANCESTRAL_RECORD_VERSION);

            // Write the ancestral and current tokens
            af.writeLong(mAncestralToken);
            af.writeLong(mCurrentToken);

            // Now write the set of ancestral packages
            if (mAncestralPackages == null) {
                af.writeInt(-1);
            } else {
                af.writeInt(mAncestralPackages.size());
                if (DEBUG) Slog.v(TAG, "Ancestral packages:  " + mAncestralPackages.size());
                for (String pkgName : mAncestralPackages) {
                    af.writeUTF(pkgName);
                    if (MORE_DEBUG) Slog.v(TAG, "   " + pkgName);
                }
            }
            af.close();
        } catch (IOException e) {
            Slog.w(TAG, "Unable to write token file:", e);
        }
    }

    // What name is this transport registered under...?
    private String getTransportName(IBackupTransport transport) {
        if (MORE_DEBUG) {
            Slog.v(TAG, "Searching for transport name of " + transport);
        }
        return mTransportManager.getTransportName(transport);
    }

    // fire off a backup agent, blocking until it attaches or times out
    @Override
    public IBackupAgent bindToAgentSynchronous(ApplicationInfo app, int mode) {
        IBackupAgent agent = null;
        synchronized(mAgentConnectLock) {
            mConnecting = true;
            mConnectedAgent = null;
            try {
                if (mActivityManager.bindBackupAgent(app.packageName, mode,
                        UserHandle.USER_OWNER)) {
                    Slog.d(TAG, "awaiting agent for " + app);

                    // success; wait for the agent to arrive
                    // only wait 10 seconds for the bind to happen
                    long timeoutMark = System.currentTimeMillis() + TIMEOUT_INTERVAL;
                    while (mConnecting && mConnectedAgent == null
                            && (System.currentTimeMillis() < timeoutMark)) {
                        try {
                            mAgentConnectLock.wait(5000);
                        } catch (InterruptedException e) {
                            // just bail
                            Slog.w(TAG, "Interrupted: " + e);
                            mConnecting = false;
                            mConnectedAgent = null;
                        }
                    }

                    // if we timed out with no connect, abort and move on
                    if (mConnecting == true) {
                        Slog.w(TAG, "Timeout waiting for agent " + app);
                        mConnectedAgent = null;
                    }
                    if (DEBUG) Slog.i(TAG, "got agent " + mConnectedAgent);
                    agent = mConnectedAgent;
                }
            } catch (RemoteException e) {
                // can't happen - ActivityManager is local
            }
        }
        if (agent == null) {
            try {
                mActivityManager.clearPendingBackup();
            } catch (RemoteException e) {
                // can't happen - ActivityManager is local
            }
        }
        return agent;
    }

    // clear an application's data, blocking until the operation completes or times out
    void clearApplicationDataSynchronous(String packageName) {
        // Don't wipe packages marked allowClearUserData=false
        try {
            PackageInfo info = mPackageManager.getPackageInfo(packageName, 0);
            if ((info.applicationInfo.flags & ApplicationInfo.FLAG_ALLOW_CLEAR_USER_DATA) == 0) {
                if (MORE_DEBUG) Slog.i(TAG, "allowClearUserData=false so not wiping "
                        + packageName);
                return;
            }
        } catch (NameNotFoundException e) {
            Slog.w(TAG, "Tried to clear data for " + packageName + " but not found");
            return;
        }

        ClearDataObserver observer = new ClearDataObserver();

        synchronized(mClearDataLock) {
            mClearingData = true;
            try {
                mActivityManager.clearApplicationUserData(packageName, observer, 0);
            } catch (RemoteException e) {
                // can't happen because the activity manager is in this process
            }

            // only wait 10 seconds for the clear data to happen
            long timeoutMark = System.currentTimeMillis() + TIMEOUT_INTERVAL;
            while (mClearingData && (System.currentTimeMillis() < timeoutMark)) {
                try {
                    mClearDataLock.wait(5000);
                } catch (InterruptedException e) {
                    // won't happen, but still.
                    mClearingData = false;
                }
            }
        }
    }

    class ClearDataObserver extends IPackageDataObserver.Stub {
        public void onRemoveCompleted(String packageName, boolean succeeded) {
            synchronized(mClearDataLock) {
                mClearingData = false;
                mClearDataLock.notifyAll();
            }
        }
    }

    // Get the restore-set token for the best-available restore set for this package:
    // the active set if possible, else the ancestral one.  Returns zero if none available.
    @Override
    public long getAvailableRestoreToken(String packageName) {
        mContext.enforceCallingOrSelfPermission(android.Manifest.permission.BACKUP,
                "getAvailableRestoreToken");

        long token = mAncestralToken;
        synchronized (mQueueLock) {
            if (mCurrentToken != 0 && mEverStoredApps.contains(packageName)) {
                if (MORE_DEBUG) {
                    Slog.i(TAG, "App in ever-stored, so using current token");
                }
                token = mCurrentToken;
            }
        }
        if (MORE_DEBUG) Slog.i(TAG, "getAvailableRestoreToken() == " + token);
        return token;
    }

    @Override
    public int requestBackup(String[] packages, IBackupObserver observer, int flags) {
        return requestBackup(packages, observer, null, flags);
    }

    @Override
    public int requestBackup(String[] packages, IBackupObserver observer,
            IBackupManagerMonitor monitor, int flags) {
        mContext.enforceCallingPermission(android.Manifest.permission.BACKUP, "requestBackup");

        if (packages == null || packages.length < 1) {
            Slog.e(TAG, "No packages named for backup request");
            sendBackupFinished(observer, BackupManager.ERROR_TRANSPORT_ABORTED);
            monitor = monitorEvent(monitor, BackupManagerMonitor.LOG_EVENT_ID_NO_PACKAGES,
                    null, BackupManagerMonitor.LOG_EVENT_CATEGORY_TRANSPORT, null);
            throw new IllegalArgumentException("No packages are provided for backup");
        }

        if (!mEnabled || !mProvisioned) {
            Slog.i(TAG, "Backup requested but e=" + mEnabled + " p=" +mProvisioned);
            sendBackupFinished(observer, BackupManager.ERROR_BACKUP_NOT_ALLOWED);
            final int logTag = mProvisioned
                    ? BackupManagerMonitor.LOG_EVENT_ID_BACKUP_DISABLED
                    : BackupManagerMonitor.LOG_EVENT_ID_DEVICE_NOT_PROVISIONED;
            monitor = monitorEvent(monitor, logTag, null,
                    BackupManagerMonitor.LOG_EVENT_CATEGORY_BACKUP_MANAGER_POLICY, null);
            return BackupManager.ERROR_BACKUP_NOT_ALLOWED;
        }

        IBackupTransport transport = mTransportManager.getCurrentTransportBinder();
        if (transport == null) {
            sendBackupFinished(observer, BackupManager.ERROR_TRANSPORT_ABORTED);
            monitor = monitorEvent(monitor, BackupManagerMonitor.LOG_EVENT_ID_TRANSPORT_IS_NULL,
                    null, BackupManagerMonitor.LOG_EVENT_CATEGORY_TRANSPORT, null);
            return BackupManager.ERROR_TRANSPORT_ABORTED;
        }

        ArrayList<String> fullBackupList = new ArrayList<>();
        ArrayList<String> kvBackupList = new ArrayList<>();
        for (String packageName : packages) {
            if (PACKAGE_MANAGER_SENTINEL.equals(packageName)) {
                kvBackupList.add(packageName);
                continue;
            }
            try {
                PackageInfo packageInfo = mPackageManager.getPackageInfo(packageName,
                        PackageManager.GET_SIGNATURES);
                if (!appIsEligibleForBackup(packageInfo.applicationInfo, mPackageManager)) {
                    sendBackupOnPackageResult(observer, packageName,
                            BackupManager.ERROR_BACKUP_NOT_ALLOWED);
                    continue;
                }
                if (appGetsFullBackup(packageInfo)) {
                    fullBackupList.add(packageInfo.packageName);
                } else {
                    kvBackupList.add(packageInfo.packageName);
                }
            } catch (NameNotFoundException e) {
                sendBackupOnPackageResult(observer, packageName,
                        BackupManager.ERROR_PACKAGE_NOT_FOUND);
            }
        }
        EventLog.writeEvent(EventLogTags.BACKUP_REQUESTED, packages.length, kvBackupList.size(),
                fullBackupList.size());
        if (MORE_DEBUG) {
            Slog.i(TAG, "Backup requested for " + packages.length + " packages, of them: " +
                fullBackupList.size() + " full backups, " + kvBackupList.size() + " k/v backups");
        }

        String dirName;
        try {
            dirName = transport.transportDirName();
        } catch (Exception e) {
            Slog.e(TAG, "Transport unavailable while attempting backup: " + e.getMessage());
            sendBackupFinished(observer, BackupManager.ERROR_TRANSPORT_ABORTED);
            return BackupManager.ERROR_TRANSPORT_ABORTED;
        }

        boolean nonIncrementalBackup = (flags & BackupManager.FLAG_NON_INCREMENTAL_BACKUP) != 0;

        Message msg = mBackupHandler.obtainMessage(MSG_REQUEST_BACKUP);
        msg.obj = new BackupParams(transport, dirName, kvBackupList, fullBackupList, observer,
                monitor, true, nonIncrementalBackup);
        mBackupHandler.sendMessage(msg);
        return BackupManager.SUCCESS;
    }

    // Cancel all running backups.
    @Override
    public void cancelBackups(){
        mContext.enforceCallingPermission(android.Manifest.permission.BACKUP, "cancelBackups");
        if (MORE_DEBUG) {
            Slog.i(TAG, "cancelBackups() called.");
        }
        final long oldToken = Binder.clearCallingIdentity();
        try {
            List<Integer> operationsToCancel = new ArrayList<>();
            synchronized (mCurrentOpLock) {
                for (int i = 0; i < mCurrentOperations.size(); i++) {
                    Operation op = mCurrentOperations.valueAt(i);
                    int token = mCurrentOperations.keyAt(i);
                    if (op.type == OP_TYPE_BACKUP) {
                        operationsToCancel.add(token);
                    }
                }
            }
            for (Integer token : operationsToCancel) {
                handleCancel(token, true /* cancelAll */);
            }
            // We don't want the backup jobs to kick in any time soon.
            // Reschedules them to run in the distant future.
            KeyValueBackupJob.schedule(mContext, BUSY_BACKOFF_MIN_MILLIS);
            FullBackupJob.schedule(mContext, 2 * BUSY_BACKOFF_MIN_MILLIS);
        } finally {
            Binder.restoreCallingIdentity(oldToken);
        }
    }

    @Override
    public void prepareOperationTimeout(int token, long interval, BackupRestoreTask callback,
        int operationType) {
        if (operationType != OP_TYPE_BACKUP_WAIT && operationType != OP_TYPE_RESTORE_WAIT) {
            Slog.wtf(TAG, "prepareOperationTimeout() doesn't support operation " +
                    Integer.toHexString(token) + " of type " + operationType);
            return;
        }
        if (MORE_DEBUG) Slog.v(TAG, "starting timeout: token=" + Integer.toHexString(token)
                + " interval=" + interval + " callback=" + callback);

        synchronized (mCurrentOpLock) {
            mCurrentOperations.put(token, new Operation(OP_PENDING, callback, operationType));
            Message msg = mBackupHandler.obtainMessage(getMessageIdForOperationType(operationType),
                    token, 0, callback);
            mBackupHandler.sendMessageDelayed(msg, interval);
        }
    }

    private int getMessageIdForOperationType(int operationType) {
        switch (operationType) {
            case OP_TYPE_BACKUP_WAIT:
                return MSG_BACKUP_OPERATION_TIMEOUT;
            case OP_TYPE_RESTORE_WAIT:
                return MSG_RESTORE_OPERATION_TIMEOUT;
            default:
                Slog.wtf(TAG, "getMessageIdForOperationType called on invalid operation type: " +
                        operationType);
                return -1;
        }
    }

    private void removeOperation(int token) {
        if (MORE_DEBUG) {
            Slog.d(TAG, "Removing operation token=" + Integer.toHexString(token));
        }
        synchronized (mCurrentOpLock) {
            if (mCurrentOperations.get(token) == null) {
                Slog.w(TAG, "Duplicate remove for operation. token=" +
                        Integer.toHexString(token));
            }
            mCurrentOperations.remove(token);
        }
    }

    // synchronous waiter case
    @Override
    public boolean waitUntilOperationComplete(int token) {
        if (MORE_DEBUG) Slog.i(TAG, "Blocking until operation complete for "
                + Integer.toHexString(token));
        int finalState = OP_PENDING;
        Operation op = null;
        synchronized (mCurrentOpLock) {
            while (true) {
                op = mCurrentOperations.get(token);
                if (op == null) {
                    // mysterious disappearance: treat as success with no callback
                    break;
                } else {
                    if (op.state == OP_PENDING) {
                        try {
                            mCurrentOpLock.wait();
                        } catch (InterruptedException e) {
                        }
                        // When the wait is notified we loop around and recheck the current state
                    } else {
                        if (MORE_DEBUG) {
                            Slog.d(TAG, "Unblocked waiting for operation token=" +
                                    Integer.toHexString(token));
                        }
                        // No longer pending; we're done
                        finalState = op.state;
                        break;
                    }
                }
            }
        }

        removeOperation(token);
        if (op != null) {
            mBackupHandler.removeMessages(getMessageIdForOperationType(op.type));
        }
        if (MORE_DEBUG) Slog.v(TAG, "operation " + Integer.toHexString(token)
                + " complete: finalState=" + finalState);
        return finalState == OP_ACKNOWLEDGED;
    }

    void handleCancel(int token, boolean cancelAll) {
        // Notify any synchronous waiters
        Operation op = null;
        synchronized (mCurrentOpLock) {
            op = mCurrentOperations.get(token);
            if (MORE_DEBUG) {
                if (op == null) Slog.w(TAG, "Cancel of token " + Integer.toHexString(token)
                        + " but no op found");
            }
            int state = (op != null) ? op.state : OP_TIMEOUT;
            if (state == OP_ACKNOWLEDGED) {
                // The operation finished cleanly, so we have nothing more to do.
                if (DEBUG) {
                    Slog.w(TAG, "Operation already got an ack." +
                            "Should have been removed from mCurrentOperations.");
                }
                op = null;
                mCurrentOperations.delete(token);
            } else if (state == OP_PENDING) {
                if (DEBUG) Slog.v(TAG, "Cancel: token=" + Integer.toHexString(token));
                op.state = OP_TIMEOUT;
                // Can't delete op from mCurrentOperations here. waitUntilOperationComplete may be
                // called after we receive cancel here. We need this op's state there.

                // Remove all pending timeout messages of types OP_TYPE_BACKUP_WAIT and
                // OP_TYPE_RESTORE_WAIT. On the other hand, OP_TYPE_BACKUP cannot time out and
                // doesn't require cancellation.
                if (op.type == OP_TYPE_BACKUP_WAIT || op.type == OP_TYPE_RESTORE_WAIT) {
                    mBackupHandler.removeMessages(getMessageIdForOperationType(op.type));
                }
            }
            mCurrentOpLock.notifyAll();
        }

        // If there's a TimeoutHandler for this event, call it
        if (op != null && op.callback != null) {
            if (MORE_DEBUG) {
                Slog.v(TAG, "   Invoking cancel on " + op.callback);
            }
            op.callback.handleCancel(cancelAll);
        }
    }

    // ----- Back up a set of applications via a worker thread -----

    enum BackupState {
        INITIAL,
        RUNNING_QUEUE,
        FINAL
    }

    /**
     * This class handles the process of backing up a given list of key/value backup packages.
     * Also takes in a list of pending dolly backups and kicks them off when key/value backups
     * are done.
     *
     * Flow:
     * If required, backup @pm@.
     * For each pending key/value backup package:
     *     - Bind to agent.
     *     - Call agent.doBackup()
     *     - Wait either for cancel/timeout or operationComplete() callback from the agent.
     * Start task to perform dolly backups.
     *
     * There are three entry points into this class:
     *     - execute() [Called from the handler thread]
     *     - operationComplete(long result) [Called from the handler thread]
     *     - handleCancel(boolean cancelAll) [Can be called from any thread]
     * These methods synchronize on mCancelLock.
     *
     * Interaction with mCurrentOperations:
     *     - An entry for this task is put into mCurrentOperations for the entire lifetime of the
     *       task. This is useful to cancel the task if required.
     *     - An ephemeral entry is put into mCurrentOperations each time we are waiting on for
     *       response from a backup agent. This is used to plumb timeouts and completion callbacks.
     */
    class PerformBackupTask implements BackupRestoreTask {
        private static final String TAG = "PerformBackupTask";

        private final Object mCancelLock = new Object();

        IBackupTransport mTransport;
        ArrayList<BackupRequest> mQueue;
        ArrayList<BackupRequest> mOriginalQueue;
        File mStateDir;
        File mJournal;
        BackupState mCurrentState;
        List<String> mPendingFullBackups;
        IBackupObserver mObserver;
        IBackupManagerMonitor mMonitor;

        private final PerformFullTransportBackupTask mFullBackupTask;
        private final int mCurrentOpToken;
        private volatile int mEphemeralOpToken;

        // carried information about the current in-flight operation
        IBackupAgent mAgentBinder;
        PackageInfo mCurrentPackage;
        File mSavedStateName;
        File mBackupDataName;
        File mNewStateName;
        ParcelFileDescriptor mSavedState;
        ParcelFileDescriptor mBackupData;
        ParcelFileDescriptor mNewState;
        int mStatus;
        boolean mFinished;
        final boolean mUserInitiated;
        final boolean mNonIncremental;

        private volatile boolean mCancelAll;

        public PerformBackupTask(IBackupTransport transport, String dirName,
                ArrayList<BackupRequest> queue, File journal, IBackupObserver observer,
                IBackupManagerMonitor monitor, List<String> pendingFullBackups,
                boolean userInitiated, boolean nonIncremental) {
            mTransport = transport;
            mOriginalQueue = queue;
            mQueue = new ArrayList<>();
            mJournal = journal;
            mObserver = observer;
            mMonitor = monitor;
            mPendingFullBackups = pendingFullBackups;
            mUserInitiated = userInitiated;
            mNonIncremental = nonIncremental;

            mStateDir = new File(mBaseStateDir, dirName);
            mCurrentOpToken = generateRandomIntegerToken();

            mFinished = false;

            synchronized (mCurrentOpLock) {
                if (isBackupOperationInProgress()) {
                    if (DEBUG) {
                        Slog.d(TAG, "Skipping backup since one is already in progress.");
                    }
                    mCancelAll = true;
                    mFullBackupTask = null;
                    mCurrentState = BackupState.FINAL;
                    addBackupTrace("Skipped. Backup already in progress.");
                } else {
                    mCurrentState = BackupState.INITIAL;
                    CountDownLatch latch = new CountDownLatch(1);
                    String[] fullBackups =
                            mPendingFullBackups.toArray(new String[mPendingFullBackups.size()]);
                    mFullBackupTask =
                            new PerformFullTransportBackupTask(/*fullBackupRestoreObserver*/ null,
                                    fullBackups, /*updateSchedule*/ false, /*runningJob*/ null,
                                    latch,
                                    mObserver, mMonitor, mUserInitiated);

                    registerTask();
                    addBackupTrace("STATE => INITIAL");
                }
            }
        }

        /**
         * Put this task in the repository of running tasks.
         */
        private void registerTask() {
            synchronized (mCurrentOpLock) {
                mCurrentOperations.put(mCurrentOpToken, new Operation(OP_PENDING, this,
                        OP_TYPE_BACKUP));
            }
        }

        /**
         * Remove this task from repository of running tasks.
         */
        private void unregisterTask() {
            removeOperation(mCurrentOpToken);
        }

        // Main entry point: perform one chunk of work, updating the state as appropriate
        // and reposting the next chunk to the primary backup handler thread.
        @Override
        @GuardedBy("mCancelLock")
        public void execute() {
            synchronized (mCancelLock) {
                switch (mCurrentState) {
                    case INITIAL:
                        beginBackup();
                        break;

                    case RUNNING_QUEUE:
                        invokeNextAgent();
                        break;

                    case FINAL:
                        if (!mFinished) {
                            finalizeBackup();
                        } else {
                            Slog.e(TAG, "Duplicate finish of K/V pass");
                        }
                        break;
                }
            }
        }

        // We're starting a backup pass.  Initialize the transport and send
        // the PM metadata blob if we haven't already.
        void beginBackup() {
            if (DEBUG_BACKUP_TRACE) {
                clearBackupTrace();
                StringBuilder b = new StringBuilder(256);
                b.append("beginBackup: [");
                for (BackupRequest req : mOriginalQueue) {
                    b.append(' ');
                    b.append(req.packageName);
                }
                b.append(" ]");
                addBackupTrace(b.toString());
            }

            mAgentBinder = null;
            mStatus = BackupTransport.TRANSPORT_OK;

            // Sanity check: if the queue is empty we have no work to do.
            if (mOriginalQueue.isEmpty() && mPendingFullBackups.isEmpty()) {
                Slog.w(TAG, "Backup begun with an empty queue - nothing to do.");
                addBackupTrace("queue empty at begin");
                sendBackupFinished(mObserver, BackupManager.SUCCESS);
                executeNextState(BackupState.FINAL);
                return;
            }

            // We need to retain the original queue contents in case of transport
            // failure, but we want a working copy that we can manipulate along
            // the way.
            mQueue = (ArrayList<BackupRequest>) mOriginalQueue.clone();

            // When the transport is forcing non-incremental key/value payloads, we send the
            // metadata only if it explicitly asks for it.
            boolean skipPm = mNonIncremental;

            // The app metadata pseudopackage might also be represented in the
            // backup queue if apps have been added/removed since the last time
            // we performed a backup.  Drop it from the working queue now that
            // we're committed to evaluating it for backup regardless.
            for (int i = 0; i < mQueue.size(); i++) {
                if (PACKAGE_MANAGER_SENTINEL.equals(mQueue.get(i).packageName)) {
                    if (MORE_DEBUG) {
                        Slog.i(TAG, "Metadata in queue; eliding");
                    }
                    mQueue.remove(i);
                    skipPm = false;
                    break;
                }
            }

            if (DEBUG) Slog.v(TAG, "Beginning backup of " + mQueue.size() + " targets");

            File pmState = new File(mStateDir, PACKAGE_MANAGER_SENTINEL);
            try {
                final String transportName = mTransport.transportDirName();
                EventLog.writeEvent(EventLogTags.BACKUP_START, transportName);

                // If we haven't stored package manager metadata yet, we must init the transport.
                if (mStatus == BackupTransport.TRANSPORT_OK && pmState.length() <= 0) {
                    Slog.i(TAG, "Initializing (wiping) backup state and transport storage");
                    addBackupTrace("initializing transport " + transportName);
                    resetBackupState(mStateDir);  // Just to make sure.
                    mStatus = mTransport.initializeDevice();

                    addBackupTrace("transport.initializeDevice() == " + mStatus);
                    if (mStatus == BackupTransport.TRANSPORT_OK) {
                        EventLog.writeEvent(EventLogTags.BACKUP_INITIALIZE);
                    } else {
                        EventLog.writeEvent(EventLogTags.BACKUP_TRANSPORT_FAILURE, "(initialize)");
                        Slog.e(TAG, "Transport error in initializeDevice()");
                    }
                }

                if (skipPm) {
                    Slog.d(TAG, "Skipping backup of package metadata.");
                    executeNextState(BackupState.RUNNING_QUEUE);
                } else {
                    // The package manager doesn't have a proper <application> etc, but since
                    // it's running here in the system process we can just set up its agent
                    // directly and use a synthetic BackupRequest.  We always run this pass
                    // because it's cheap and this way we guarantee that we don't get out of
                    // step even if we're selecting among various transports at run time.
                    if (mStatus == BackupTransport.TRANSPORT_OK) {
                        PackageManagerBackupAgent pmAgent = makeMetadataAgent();
                        mStatus = invokeAgentForBackup(PACKAGE_MANAGER_SENTINEL,
                                IBackupAgent.Stub.asInterface(pmAgent.onBind()), mTransport);
                        addBackupTrace("PMBA invoke: " + mStatus);

                        // Because the PMBA is a local instance, it has already executed its
                        // backup callback and returned.  Blow away the lingering (spurious)
                        // pending timeout message for it.
                        mBackupHandler.removeMessages(MSG_BACKUP_OPERATION_TIMEOUT);
                    }
                }

                if (mStatus == BackupTransport.TRANSPORT_NOT_INITIALIZED) {
                    // The backend reports that our dataset has been wiped.  Note this in
                    // the event log; the no-success code below will reset the backup
                    // state as well.
                    EventLog.writeEvent(EventLogTags.BACKUP_RESET, mTransport.transportDirName());
                }
            } catch (Exception e) {
                Slog.e(TAG, "Error in backup thread", e);
                addBackupTrace("Exception in backup thread: " + e);
                mStatus = BackupTransport.TRANSPORT_ERROR;
            } finally {
                // If we've succeeded so far, invokeAgentForBackup() will have run the PM
                // metadata and its completion/timeout callback will continue the state
                // machine chain.  If it failed that won't happen; we handle that now.
                addBackupTrace("exiting prelim: " + mStatus);
                if (mStatus != BackupTransport.TRANSPORT_OK) {
                    // if things went wrong at this point, we need to
                    // restage everything and try again later.
                    resetBackupState(mStateDir);  // Just to make sure.
                    // In case of any other error, it's backup transport error.
                    sendBackupFinished(mObserver, BackupManager.ERROR_TRANSPORT_ABORTED);
                    executeNextState(BackupState.FINAL);
                }
            }
        }

        // Transport has been initialized and the PM metadata submitted successfully
        // if that was warranted.  Now we process the single next thing in the queue.
        void invokeNextAgent() {
            mStatus = BackupTransport.TRANSPORT_OK;
            addBackupTrace("invoke q=" + mQueue.size());

            // Sanity check that we have work to do.  If not, skip to the end where
            // we reestablish the wakelock invariants etc.
            if (mQueue.isEmpty()) {
                if (MORE_DEBUG) Slog.i(TAG, "queue now empty");
                executeNextState(BackupState.FINAL);
                return;
            }

            // pop the entry we're going to process on this step
            BackupRequest request = mQueue.get(0);
            mQueue.remove(0);

            Slog.d(TAG, "starting key/value backup of " + request);
            addBackupTrace("launch agent for " + request.packageName);

            // Verify that the requested app exists; it might be something that
            // requested a backup but was then uninstalled.  The request was
            // journalled and rather than tamper with the journal it's safer
            // to sanity-check here.  This also gives us the classname of the
            // package's backup agent.
            try {
                mCurrentPackage = mPackageManager.getPackageInfo(request.packageName,
                        PackageManager.GET_SIGNATURES);
                if (!appIsEligibleForBackup(mCurrentPackage.applicationInfo, mPackageManager)) {
                    // The manifest has changed but we had a stale backup request pending.
                    // This won't happen again because the app won't be requesting further
                    // backups.
                    Slog.i(TAG, "Package " + request.packageName
                            + " no longer supports backup; skipping");
                    addBackupTrace("skipping - not eligible, completion is noop");
                    // Shouldn't happen in case of requested backup, as pre-check was done in
                    // #requestBackup(), except to app update done concurrently
                    sendBackupOnPackageResult(mObserver, mCurrentPackage.packageName,
                            BackupManager.ERROR_BACKUP_NOT_ALLOWED);
                    executeNextState(BackupState.RUNNING_QUEUE);
                    return;
                }

                if (appGetsFullBackup(mCurrentPackage)) {
                    // It's possible that this app *formerly* was enqueued for key/value backup,
                    // but has since been updated and now only supports the full-data path.
                    // Don't proceed with a key/value backup for it in this case.
                    Slog.i(TAG, "Package " + request.packageName
                            + " requests full-data rather than key/value; skipping");
                    addBackupTrace("skipping - fullBackupOnly, completion is noop");
                    // Shouldn't happen in case of requested backup, as pre-check was done in
                    // #requestBackup()
                    sendBackupOnPackageResult(mObserver, mCurrentPackage.packageName,
                            BackupManager.ERROR_BACKUP_NOT_ALLOWED);
                    executeNextState(BackupState.RUNNING_QUEUE);
                    return;
                }

                if (appIsStopped(mCurrentPackage.applicationInfo)) {
                    // The app has been force-stopped or cleared or just installed,
                    // and not yet launched out of that state, so just as it won't
                    // receive broadcasts, we won't run it for backup.
                    addBackupTrace("skipping - stopped");
                    sendBackupOnPackageResult(mObserver, mCurrentPackage.packageName,
                            BackupManager.ERROR_BACKUP_NOT_ALLOWED);
                    executeNextState(BackupState.RUNNING_QUEUE);
                    return;
                }

                IBackupAgent agent = null;
                try {
                    mWakelock.setWorkSource(new WorkSource(mCurrentPackage.applicationInfo.uid));
                    agent = bindToAgentSynchronous(mCurrentPackage.applicationInfo,
                            ApplicationThreadConstants.BACKUP_MODE_INCREMENTAL);
                    addBackupTrace("agent bound; a? = " + (agent != null));
                    if (agent != null) {
                        mAgentBinder = agent;
                        mStatus = invokeAgentForBackup(request.packageName, agent, mTransport);
                        // at this point we'll either get a completion callback from the
                        // agent, or a timeout message on the main handler.  either way, we're
                        // done here as long as we're successful so far.
                    } else {
                        // Timeout waiting for the agent
                        mStatus = BackupTransport.AGENT_ERROR;
                    }
                } catch (SecurityException ex) {
                    // Try for the next one.
                    Slog.d(TAG, "error in bind/backup", ex);
                    mStatus = BackupTransport.AGENT_ERROR;
                            addBackupTrace("agent SE");
                }
            } catch (NameNotFoundException e) {
                Slog.d(TAG, "Package does not exist; skipping");
                addBackupTrace("no such package");
                mStatus = BackupTransport.AGENT_UNKNOWN;
            } finally {
                mWakelock.setWorkSource(null);

                // If there was an agent error, no timeout/completion handling will occur.
                // That means we need to direct to the next state ourselves.
                if (mStatus != BackupTransport.TRANSPORT_OK) {
                    BackupState nextState = BackupState.RUNNING_QUEUE;
                    mAgentBinder = null;

                    // An agent-level failure means we reenqueue this one agent for
                    // a later retry, but otherwise proceed normally.
                    if (mStatus == BackupTransport.AGENT_ERROR) {
                        if (MORE_DEBUG) Slog.i(TAG, "Agent failure for " + request.packageName
                                + " - restaging");
                        dataChangedImpl(request.packageName);
                        mStatus = BackupTransport.TRANSPORT_OK;
                        if (mQueue.isEmpty()) nextState = BackupState.FINAL;
                        sendBackupOnPackageResult(mObserver, mCurrentPackage.packageName,
                                BackupManager.ERROR_AGENT_FAILURE);
                    } else if (mStatus == BackupTransport.AGENT_UNKNOWN) {
                        // Failed lookup of the app, so we couldn't bring up an agent, but
                        // we're otherwise fine.  Just drop it and go on to the next as usual.
                        mStatus = BackupTransport.TRANSPORT_OK;
                        sendBackupOnPackageResult(mObserver, mCurrentPackage.packageName,
                                BackupManager.ERROR_PACKAGE_NOT_FOUND);
                    } else {
                        // Transport-level failure means we reenqueue everything
                        revertAndEndBackup();
                        nextState = BackupState.FINAL;
                    }

                    executeNextState(nextState);
                } else {
                    // success case
                    addBackupTrace("expecting completion/timeout callback");
                }
            }
        }

        void finalizeBackup() {
            addBackupTrace("finishing");

            // Mark packages that we didn't backup (because backup was cancelled, etc.) as needing
            // backup.
            for (BackupRequest req : mQueue) {
                dataChangedImpl(req.packageName);
            }

            // Either backup was successful, in which case we of course do not need
            // this pass's journal any more; or it failed, in which case we just
            // re-enqueued all of these packages in the current active journal.
            // Either way, we no longer need this pass's journal.
            if (mJournal != null && !mJournal.delete()) {
                Slog.e(TAG, "Unable to remove backup journal file " + mJournal);
            }

            // If everything actually went through and this is the first time we've
            // done a backup, we can now record what the current backup dataset token
            // is.
            if ((mCurrentToken == 0) && (mStatus == BackupTransport.TRANSPORT_OK)) {
                addBackupTrace("success; recording token");
                try {
                    mCurrentToken = mTransport.getCurrentRestoreSet();
                    writeRestoreTokens();
                } catch (Exception e) {
                    // nothing for it at this point, unfortunately, but this will be
                    // recorded the next time we fully succeed.
                    Slog.e(TAG, "Transport threw reporting restore set: " + e.getMessage());
                    addBackupTrace("transport threw returning token");
                }
            }

            // Set up the next backup pass - at this point we can set mBackupRunning
            // to false to allow another pass to fire, because we're done with the
            // state machine sequence and the wakelock is refcounted.
            synchronized (mQueueLock) {
                mBackupRunning = false;
                if (mStatus == BackupTransport.TRANSPORT_NOT_INITIALIZED) {
                    // Make sure we back up everything and perform the one-time init
                    if (MORE_DEBUG) Slog.d(TAG, "Server requires init; rerunning");
                    addBackupTrace("init required; rerunning");
                    try {
                        final String name = mTransportManager.getTransportName(mTransport);
                        if (name != null) {
                            mPendingInits.add(name);
                        } else {
                            if (DEBUG) {
                                Slog.w(TAG, "Couldn't find name of transport " + mTransport
                                        + " for init");
                            }
                        }
                    } catch (Exception e) {
                        Slog.w(TAG, "Failed to query transport name for init: " + e.getMessage());
                        // swallow it and proceed; we don't rely on this
                    }
                    clearMetadata();
                    backupNow();
                }
            }

            clearBackupTrace();

            unregisterTask();

            if (!mCancelAll && mStatus == BackupTransport.TRANSPORT_OK &&
                    mPendingFullBackups != null && !mPendingFullBackups.isEmpty()) {
                Slog.d(TAG, "Starting full backups for: " + mPendingFullBackups);
                // Acquiring wakelock for PerformFullTransportBackupTask before its start.
                mWakelock.acquire();
                (new Thread(mFullBackupTask, "full-transport-requested")).start();
            } else if (mCancelAll) {
                if (mFullBackupTask != null) {
                    mFullBackupTask.unregisterTask();
                }
                sendBackupFinished(mObserver, BackupManager.ERROR_BACKUP_CANCELLED);
            } else {
                mFullBackupTask.unregisterTask();
                switch (mStatus) {
                    case BackupTransport.TRANSPORT_OK:
                        sendBackupFinished(mObserver, BackupManager.SUCCESS);
                        break;
                    case BackupTransport.TRANSPORT_NOT_INITIALIZED:
                        sendBackupFinished(mObserver, BackupManager.ERROR_TRANSPORT_ABORTED);
                        break;
                    case BackupTransport.TRANSPORT_ERROR:
                    default:
                        sendBackupFinished(mObserver, BackupManager.ERROR_TRANSPORT_ABORTED);
                        break;
                }
            }
            mFinished = true;
            Slog.i(BackupManagerService.TAG, "K/V backup pass finished.");
            // Only once we're entirely finished do we release the wakelock for k/v backup.
            mWakelock.release();
        }

        // Remove the PM metadata state. This will generate an init on the next pass.
        void clearMetadata() {
            final File pmState = new File(mStateDir, PACKAGE_MANAGER_SENTINEL);
            if (pmState.exists()) pmState.delete();
        }

        // Invoke an agent's doBackup() and start a timeout message spinning on the main
        // handler in case it doesn't get back to us.
        int invokeAgentForBackup(String packageName, IBackupAgent agent,
                IBackupTransport transport) {
            if (DEBUG) Slog.d(TAG, "invokeAgentForBackup on " + packageName);
            addBackupTrace("invoking " + packageName);

            File blankStateName = new File(mStateDir, "blank_state");
            mSavedStateName = new File(mStateDir, packageName);
            mBackupDataName = new File(mDataDir, packageName + ".data");
            mNewStateName = new File(mStateDir, packageName + ".new");
            if (MORE_DEBUG) Slog.d(TAG, "data file: " + mBackupDataName);

            mSavedState = null;
            mBackupData = null;
            mNewState = null;

            boolean callingAgent = false;
            mEphemeralOpToken = generateRandomIntegerToken();
            try {
                // Look up the package info & signatures.  This is first so that if it
                // throws an exception, there's no file setup yet that would need to
                // be unraveled.
                if (packageName.equals(PACKAGE_MANAGER_SENTINEL)) {
                    // The metadata 'package' is synthetic; construct one and make
                    // sure our global state is pointed at it
                    mCurrentPackage = new PackageInfo();
                    mCurrentPackage.packageName = packageName;
                }

                // In a full backup, we pass a null ParcelFileDescriptor as
                // the saved-state "file". For key/value backups we pass the old state if
                // an incremental backup is required, and a blank state otherwise.
                mSavedState = ParcelFileDescriptor.open(
                        mNonIncremental ? blankStateName : mSavedStateName,
                        ParcelFileDescriptor.MODE_READ_ONLY |
                        ParcelFileDescriptor.MODE_CREATE);  // Make an empty file if necessary

                mBackupData = ParcelFileDescriptor.open(mBackupDataName,
                        ParcelFileDescriptor.MODE_READ_WRITE |
                        ParcelFileDescriptor.MODE_CREATE |
                        ParcelFileDescriptor.MODE_TRUNCATE);

                if (!SELinux.restorecon(mBackupDataName)) {
                    Slog.e(TAG, "SELinux restorecon failed on " + mBackupDataName);
                }

                mNewState = ParcelFileDescriptor.open(mNewStateName,
                        ParcelFileDescriptor.MODE_READ_WRITE |
                        ParcelFileDescriptor.MODE_CREATE |
                        ParcelFileDescriptor.MODE_TRUNCATE);

                final long quota = mTransport.getBackupQuota(packageName, false /* isFullBackup */);
                callingAgent = true;

                // Initiate the target's backup pass
                addBackupTrace("setting timeout");
                prepareOperationTimeout(mEphemeralOpToken, TIMEOUT_BACKUP_INTERVAL, this,
                        OP_TYPE_BACKUP_WAIT);
                addBackupTrace("calling agent doBackup()");

                agent.doBackup(mSavedState, mBackupData, mNewState, quota, mEphemeralOpToken,
                        mBackupManagerBinder);
            } catch (Exception e) {
                Slog.e(TAG, "Error invoking for backup on " + packageName + ". " + e);
                addBackupTrace("exception: " + e);
                EventLog.writeEvent(EventLogTags.BACKUP_AGENT_FAILURE, packageName,
                        e.toString());
                errorCleanup();
                return callingAgent ? BackupTransport.AGENT_ERROR
                        : BackupTransport.TRANSPORT_ERROR;
            } finally {
                if (mNonIncremental) {
                    blankStateName.delete();
                }
            }

            // At this point the agent is off and running.  The next thing to happen will
            // either be a callback from the agent, at which point we'll process its data
            // for transport, or a timeout.  Either way the next phase will happen in
            // response to the TimeoutHandler interface callbacks.
            addBackupTrace("invoke success");
            return BackupTransport.TRANSPORT_OK;
        }

        public void failAgent(IBackupAgent agent, String message) {
            try {
                agent.fail(message);
            } catch (Exception e) {
                Slog.w(TAG, "Error conveying failure to " + mCurrentPackage.packageName);
            }
        }

        // SHA-1 a byte array and return the result in hex
        private String SHA1Checksum(byte[] input) {
            final byte[] checksum;
            try {
                MessageDigest md = MessageDigest.getInstance("SHA-1");
                checksum = md.digest(input);
            } catch (NoSuchAlgorithmException e) {
                Slog.e(TAG, "Unable to use SHA-1!");
                return "00";
            }

            StringBuffer sb = new StringBuffer(checksum.length * 2);
            for (int i = 0; i < checksum.length; i++) {
                sb.append(Integer.toHexString(checksum[i]));
            }
            return sb.toString();
        }

        private void writeWidgetPayloadIfAppropriate(FileDescriptor fd, String pkgName)
                throws IOException {
            // TODO: http://b/22388012
            byte[] widgetState = AppWidgetBackupBridge.getWidgetState(pkgName,
                    UserHandle.USER_SYSTEM);
            // has the widget state changed since last time?
            final File widgetFile = new File(mStateDir, pkgName + "_widget");
            final boolean priorStateExists = widgetFile.exists();

            if (MORE_DEBUG) {
                if (priorStateExists || widgetState != null) {
                    Slog.i(TAG, "Checking widget update: state=" + (widgetState != null)
                            + " prior=" + priorStateExists);
                }
            }

            if (!priorStateExists && widgetState == null) {
                // no prior state, no new state => nothing to do
                return;
            }

            // if the new state is not null, we might need to compare checksums to
            // determine whether to update the widget blob in the archive.  If the
            // widget state *is* null, we know a priori at this point that we simply
            // need to commit a deletion for it.
            String newChecksum = null;
            if (widgetState != null) {
                newChecksum = SHA1Checksum(widgetState);
                if (priorStateExists) {
                    final String priorChecksum;
                    try (
                        FileInputStream fin = new FileInputStream(widgetFile);
                        DataInputStream in = new DataInputStream(fin)
                    ) {
                        priorChecksum = in.readUTF();
                    }
                    if (Objects.equals(newChecksum, priorChecksum)) {
                        // Same checksum => no state change => don't rewrite the widget data
                        return;
                    }
                }
            } // else widget state *became* empty, so we need to commit a deletion

            BackupDataOutput out = new BackupDataOutput(fd);
            if (widgetState != null) {
                try (
                    FileOutputStream fout = new FileOutputStream(widgetFile);
                    DataOutputStream stateOut = new DataOutputStream(fout)
                ) {
                    stateOut.writeUTF(newChecksum);
                }

                out.writeEntityHeader(KEY_WIDGET_STATE, widgetState.length);
                out.writeEntityData(widgetState, widgetState.length);
            } else {
                // Widget state for this app has been removed; commit a deletion
                out.writeEntityHeader(KEY_WIDGET_STATE, -1);
                widgetFile.delete();
            }
        }

        @Override
        @GuardedBy("mCancelLock")
        public void operationComplete(long unusedResult) {
            removeOperation(mEphemeralOpToken);
            synchronized (mCancelLock) {
                // The agent reported back to us!
                if (mFinished) {
                    Slog.d(TAG, "operationComplete received after task finished.");
                    return;
                }

                if (mBackupData == null) {
                    // This callback was racing with our timeout, so we've cleaned up the
                    // agent state already and are on to the next thing.  We have nothing
                    // further to do here: agent state having been cleared means that we've
                    // initiated the appropriate next operation.
                    final String pkg = (mCurrentPackage != null)
                            ? mCurrentPackage.packageName : "[none]";
                    if (MORE_DEBUG) {
                        Slog.i(TAG, "Callback after agent teardown: " + pkg);
                    }
                    addBackupTrace("late opComplete; curPkg = " + pkg);
                    return;
                }

                final String pkgName = mCurrentPackage.packageName;
                final long filepos = mBackupDataName.length();
                FileDescriptor fd = mBackupData.getFileDescriptor();
                try {
                    // If it's a 3rd party app, see whether they wrote any protected keys
                    // and complain mightily if they are attempting shenanigans.
                    if (mCurrentPackage.applicationInfo != null &&
                            (mCurrentPackage.applicationInfo.flags & ApplicationInfo.FLAG_SYSTEM)
                                    == 0) {
                        ParcelFileDescriptor readFd = ParcelFileDescriptor.open(mBackupDataName,
                                ParcelFileDescriptor.MODE_READ_ONLY);
                        BackupDataInput in = new BackupDataInput(readFd.getFileDescriptor());
                        try {
                            while (in.readNextHeader()) {
                                final String key = in.getKey();
                                if (key != null && key.charAt(0) >= 0xff00) {
                                    // Not okay: crash them and bail.
                                    failAgent(mAgentBinder, "Illegal backup key: " + key);
                                    addBackupTrace("illegal key " + key + " from " + pkgName);
                                    EventLog.writeEvent(EventLogTags.BACKUP_AGENT_FAILURE, pkgName,
                                            "bad key");
                                    mMonitor = monitorEvent(mMonitor,
                                            BackupManagerMonitor.LOG_EVENT_ID_ILLEGAL_KEY,
                                            mCurrentPackage,
                                            BackupManagerMonitor
                                                    .LOG_EVENT_CATEGORY_BACKUP_MANAGER_POLICY,
                                            putMonitoringExtra(null,
                                                    BackupManagerMonitor.EXTRA_LOG_ILLEGAL_KEY,
                                                    key));
                                    mBackupHandler.removeMessages(MSG_BACKUP_OPERATION_TIMEOUT);
                                    sendBackupOnPackageResult(mObserver, pkgName,
                                            BackupManager.ERROR_AGENT_FAILURE);
                                    errorCleanup();
                                    // agentErrorCleanup() implicitly executes next state properly
                                    return;
                                }
                                in.skipEntityData();
                            }
                        } finally {
                            if (readFd != null) {
                                readFd.close();
                            }
                        }
                    }

                    // Piggyback the widget state payload, if any
                    writeWidgetPayloadIfAppropriate(fd, pkgName);
                } catch (IOException e) {
                    // Hard disk error; recovery/failure policy TBD.  For now roll back,
                    // but we may want to consider this a transport-level failure (i.e.
                    // we're in such a bad state that we can't contemplate doing backup
                    // operations any more during this pass).
                    Slog.w(TAG, "Unable to save widget state for " + pkgName);
                    try {
                        Os.ftruncate(fd, filepos);
                    } catch (ErrnoException ee) {
                        Slog.w(TAG, "Unable to roll back!");
                    }
                }

                // Spin the data off to the transport and proceed with the next stage.
                if (MORE_DEBUG) Slog.v(TAG, "operationComplete(): sending data to transport for "
                        + pkgName);
                mBackupHandler.removeMessages(MSG_BACKUP_OPERATION_TIMEOUT);
                clearAgentState();
                addBackupTrace("operation complete");

                ParcelFileDescriptor backupData = null;
                mStatus = BackupTransport.TRANSPORT_OK;
                long size = 0;
                try {
                    size = mBackupDataName.length();
                    if (size > 0) {
                        if (mStatus == BackupTransport.TRANSPORT_OK) {
                            backupData = ParcelFileDescriptor.open(mBackupDataName,
                                    ParcelFileDescriptor.MODE_READ_ONLY);
                            addBackupTrace("sending data to transport");
                            int flags = mUserInitiated ? BackupTransport.FLAG_USER_INITIATED : 0;
                            mStatus = mTransport.performBackup(mCurrentPackage, backupData, flags);
                        }

                        // TODO - We call finishBackup() for each application backed up, because
                        // we need to know now whether it succeeded or failed.  Instead, we should
                        // hold off on finishBackup() until the end, which implies holding off on
                        // renaming *all* the output state files (see below) until that happens.

                        addBackupTrace("data delivered: " + mStatus);
                        if (mStatus == BackupTransport.TRANSPORT_OK) {
                            addBackupTrace("finishing op on transport");
                            mStatus = mTransport.finishBackup();
                            addBackupTrace("finished: " + mStatus);
                        } else if (mStatus == BackupTransport.TRANSPORT_PACKAGE_REJECTED) {
                            addBackupTrace("transport rejected package");
                        }
                    } else {
                        if (MORE_DEBUG) Slog.i(TAG,
                                "no backup data written; not calling transport");
                        addBackupTrace("no data to send");
                        mMonitor = monitorEvent(mMonitor,
                                BackupManagerMonitor.LOG_EVENT_ID_NO_DATA_TO_SEND,
                                mCurrentPackage,
                                BackupManagerMonitor.LOG_EVENT_CATEGORY_BACKUP_MANAGER_POLICY,
                                null);
                    }

                    if (mStatus == BackupTransport.TRANSPORT_OK) {
                        // After successful transport, delete the now-stale data
                        // and juggle the files so that next time we supply the agent
                        // with the new state file it just created.
                        mBackupDataName.delete();
                        mNewStateName.renameTo(mSavedStateName);
                        sendBackupOnPackageResult(mObserver, pkgName, BackupManager.SUCCESS);
                        EventLog.writeEvent(EventLogTags.BACKUP_PACKAGE, pkgName, size);
                        logBackupComplete(pkgName);
                    } else if (mStatus == BackupTransport.TRANSPORT_PACKAGE_REJECTED) {
                        // The transport has rejected backup of this specific package.  Roll it
                        // back but proceed with running the rest of the queue.
                        mBackupDataName.delete();
                        mNewStateName.delete();
                        sendBackupOnPackageResult(mObserver, pkgName,
                                BackupManager.ERROR_TRANSPORT_PACKAGE_REJECTED);
                        EventLogTags.writeBackupAgentFailure(pkgName, "Transport rejected");
                    } else if (mStatus == BackupTransport.TRANSPORT_QUOTA_EXCEEDED) {
                        sendBackupOnPackageResult(mObserver, pkgName,
                                BackupManager.ERROR_TRANSPORT_QUOTA_EXCEEDED);
                        EventLog.writeEvent(EventLogTags.BACKUP_QUOTA_EXCEEDED, pkgName);
                    } else {
                        // Actual transport-level failure to communicate the data to the backend
                        sendBackupOnPackageResult(mObserver, pkgName,
                                BackupManager.ERROR_TRANSPORT_ABORTED);
                        EventLog.writeEvent(EventLogTags.BACKUP_TRANSPORT_FAILURE, pkgName);
                    }
                } catch (Exception e) {
                    sendBackupOnPackageResult(mObserver, pkgName,
                            BackupManager.ERROR_TRANSPORT_ABORTED);
                    Slog.e(TAG, "Transport error backing up " + pkgName, e);
                    EventLog.writeEvent(EventLogTags.BACKUP_TRANSPORT_FAILURE, pkgName);
                    mStatus = BackupTransport.TRANSPORT_ERROR;
                } finally {
                    try {
                        if (backupData != null) backupData.close();
                    } catch (IOException e) {
                    }
                }

                final BackupState nextState;
                if (mStatus == BackupTransport.TRANSPORT_OK
                        || mStatus == BackupTransport.TRANSPORT_PACKAGE_REJECTED) {
                    // Success or single-package rejection.  Proceed with the next app if any,
                    // otherwise we're done.
                    nextState = (mQueue.isEmpty()) ? BackupState.FINAL : BackupState.RUNNING_QUEUE;
                } else if (mStatus == BackupTransport.TRANSPORT_QUOTA_EXCEEDED) {
                    if (MORE_DEBUG) {
                        Slog.d(TAG, "Package " + mCurrentPackage.packageName +
                                " hit quota limit on k/v backup");
                    }
                    if (mAgentBinder != null) {
                        try {
                            long quota = mTransport.getBackupQuota(mCurrentPackage.packageName,
                                    false);
                            mAgentBinder.doQuotaExceeded(size, quota);
                        } catch (Exception e) {
                            Slog.e(TAG, "Unable to notify about quota exceeded: " + e.getMessage());
                        }
                    }
                    nextState = (mQueue.isEmpty()) ? BackupState.FINAL : BackupState.RUNNING_QUEUE;
                } else {
                    // Any other error here indicates a transport-level failure.  That means
                    // we need to halt everything and reschedule everything for next time.
                    revertAndEndBackup();
                    nextState = BackupState.FINAL;
                }

                executeNextState(nextState);
            }
        }


        @Override
        @GuardedBy("mCancelLock")
        public void handleCancel(boolean cancelAll) {
            removeOperation(mEphemeralOpToken);
            synchronized (mCancelLock) {
                if (mFinished) {
                    // We have already cancelled this operation.
                    if (MORE_DEBUG) {
                        Slog.d(TAG, "Ignoring stale cancel. cancelAll=" + cancelAll);
                    }
                    return;
                }
                mCancelAll = cancelAll;
                final String logPackageName = (mCurrentPackage != null)
                        ? mCurrentPackage.packageName
                        : "no_package_yet";
                Slog.i(TAG, "Cancel backing up " + logPackageName);
                EventLog.writeEvent(EventLogTags.BACKUP_AGENT_FAILURE, logPackageName);
                addBackupTrace("cancel of " + logPackageName + ", cancelAll=" + cancelAll);
                mMonitor = monitorEvent(mMonitor,
                        BackupManagerMonitor.LOG_EVENT_ID_KEY_VALUE_BACKUP_CANCEL,
                        mCurrentPackage, BackupManagerMonitor.LOG_EVENT_CATEGORY_AGENT,
                        putMonitoringExtra(null, BackupManagerMonitor.EXTRA_LOG_CANCEL_ALL,
                                mCancelAll));
                errorCleanup();
                if (!cancelAll) {
                    // The current agent either timed out or was cancelled running doBackup().
                    // Restage it for the next time we run a backup pass.
                    // !!! TODO: keep track of failure counts per agent, and blacklist those which
                    // fail repeatedly (i.e. have proved themselves to be buggy).
                    executeNextState(
                            mQueue.isEmpty() ? BackupState.FINAL : BackupState.RUNNING_QUEUE);
                    dataChangedImpl(mCurrentPackage.packageName);
                } else {
                    finalizeBackup();
                }
            }
        }

        void revertAndEndBackup() {
            if (MORE_DEBUG) Slog.i(TAG, "Reverting backup queue - restaging everything");
            addBackupTrace("transport error; reverting");

            // We want to reset the backup schedule based on whatever the transport suggests
            // by way of retry/backoff time.
            long delay;
            try {
                delay = mTransport.requestBackupTime();
            } catch (Exception e) {
                Slog.w(TAG, "Unable to contact transport for recommended backoff: " + e.getMessage());
                delay = 0;  // use the scheduler's default
            }
            KeyValueBackupJob.schedule(mContext, delay);

            for (BackupRequest request : mOriginalQueue) {
                dataChangedImpl(request.packageName);
            }

        }

        void errorCleanup() {
            mBackupDataName.delete();
            mNewStateName.delete();
            clearAgentState();
        }

        // Cleanup common to both success and failure cases
        void clearAgentState() {
            try { if (mSavedState != null) mSavedState.close(); } catch (IOException e) {}
            try { if (mBackupData != null) mBackupData.close(); } catch (IOException e) {}
            try { if (mNewState != null) mNewState.close(); } catch (IOException e) {}
            synchronized (mCurrentOpLock) {
                // Current-operation callback handling requires the validity of these various
                // bits of internal state as an invariant of the operation still being live.
                // This means we make sure to clear all of the state in unison inside the lock.
                mCurrentOperations.remove(mEphemeralOpToken);
                mSavedState = mBackupData = mNewState = null;
            }

            // If this was a pseudopackage there's no associated Activity Manager state
            if (mCurrentPackage.applicationInfo != null) {
                addBackupTrace("unbinding " + mCurrentPackage.packageName);
                try {  // unbind even on timeout, just in case
                    mActivityManager.unbindBackupAgent(mCurrentPackage.applicationInfo);
                } catch (RemoteException e) { /* can't happen; activity manager is local */ }
            }
        }

        void executeNextState(BackupState nextState) {
            if (MORE_DEBUG) Slog.i(TAG, " => executing next step on "
                    + this + " nextState=" + nextState);
            addBackupTrace("executeNextState => " + nextState);
            mCurrentState = nextState;
            Message msg = mBackupHandler.obtainMessage(MSG_BACKUP_RESTORE_STEP, this);
            mBackupHandler.sendMessage(msg);
        }
    }

    private boolean isBackupOperationInProgress() {
        synchronized (mCurrentOpLock) {
            for (int i = 0; i < mCurrentOperations.size(); i++) {
                Operation op = mCurrentOperations.valueAt(i);
                if (op.type == OP_TYPE_BACKUP && op.state == OP_PENDING) {
                    return true;
                }
            }
        }
        return false;
    }


    // ----- Full backup/restore to a file/socket -----

    class FullBackupObbConnection implements ServiceConnection {
        volatile IObbBackupService mService;

        FullBackupObbConnection() {
            mService = null;
        }

        public void establish() {
            if (MORE_DEBUG) Slog.i(TAG, "Initiating bind of OBB service on " + this);
            Intent obbIntent = new Intent().setComponent(new ComponentName(
                    "com.android.sharedstoragebackup",
                    "com.android.sharedstoragebackup.ObbBackupService"));
            BackupManagerService.this.mContext.bindServiceAsUser(
                    obbIntent, this, Context.BIND_AUTO_CREATE, UserHandle.SYSTEM);
        }

        public void tearDown() {
            BackupManagerService.this.mContext.unbindService(this);
        }

        public boolean backupObbs(PackageInfo pkg, OutputStream out) {
            boolean success = false;
            waitForConnection();

            ParcelFileDescriptor[] pipes = null;
            try {
                pipes = ParcelFileDescriptor.createPipe();
                int token = generateRandomIntegerToken();
                prepareOperationTimeout(token, TIMEOUT_FULL_BACKUP_INTERVAL,
                        null, OP_TYPE_BACKUP_WAIT);
                mService.backupObbs(pkg.packageName, pipes[1], token, mBackupManagerBinder);
                routeSocketDataToOutput(pipes[0], out);
                success = waitUntilOperationComplete(token);
            } catch (Exception e) {
                Slog.w(TAG, "Unable to back up OBBs for " + pkg, e);
            } finally {
                try {
                    out.flush();
                    if (pipes != null) {
                        if (pipes[0] != null) pipes[0].close();
                        if (pipes[1] != null) pipes[1].close();
                    }
                } catch (IOException e) {
                    Slog.w(TAG, "I/O error closing down OBB backup", e);
                }
            }
            return success;
        }

        public void restoreObbFile(String pkgName, ParcelFileDescriptor data,
                long fileSize, int type, String path, long mode, long mtime,
                int token, IBackupManager callbackBinder) {
            waitForConnection();

            try {
                mService.restoreObbFile(pkgName, data, fileSize, type, path, mode, mtime,
                        token, callbackBinder);
            } catch (Exception e) {
                Slog.w(TAG, "Unable to restore OBBs for " + pkgName, e);
            }
        }

        private void waitForConnection() {
            synchronized (this) {
                while (mService == null) {
                    if (MORE_DEBUG) Slog.i(TAG, "...waiting for OBB service binding...");
                    try {
                        this.wait();
                    } catch (InterruptedException e) { /* never interrupted */ }
                }
                if (MORE_DEBUG) Slog.i(TAG, "Connected to OBB service; continuing");
            }
        }

        @Override
        public void onServiceConnected(ComponentName name, IBinder service) {
            synchronized (this) {
                mService = IObbBackupService.Stub.asInterface(service);
                if (MORE_DEBUG) Slog.i(TAG, "OBB service connection " + mService
                        + " connected on " + this);
                this.notifyAll();
            }
        }

        @Override
        public void onServiceDisconnected(ComponentName name) {
            synchronized (this) {
                mService = null;
                if (MORE_DEBUG) Slog.i(TAG, "OBB service connection disconnected on " + this);
                this.notifyAll();
            }
        }

    }

    static void routeSocketDataToOutput(ParcelFileDescriptor inPipe, OutputStream out)
            throws IOException {
        // We do not take close() responsibility for the pipe FD
        FileInputStream raw = new FileInputStream(inPipe.getFileDescriptor());
        DataInputStream in = new DataInputStream(raw);

        byte[] buffer = new byte[32 * 1024];
        int chunkTotal;
        while ((chunkTotal = in.readInt()) > 0) {
            while (chunkTotal > 0) {
                int toRead = (chunkTotal > buffer.length) ? buffer.length : chunkTotal;
                int nRead = in.read(buffer, 0, toRead);
                out.write(buffer, 0, nRead);
                chunkTotal -= nRead;
            }
        }
    }

    @Override
    public void tearDownAgentAndKill(ApplicationInfo app) {
        if (app == null) {
            // Null means the system package, so just quietly move on.  :)
            return;
        }

        try {
            // unbind and tidy up even on timeout or failure, just in case
            mActivityManager.unbindBackupAgent(app);

            // The agent was running with a stub Application object, so shut it down.
            // !!! We hardcode the confirmation UI's package name here rather than use a
            //     manifest flag!  TODO something less direct.
            if (app.uid >= Process.FIRST_APPLICATION_UID
                    && !app.packageName.equals("com.android.backupconfirm")) {
                if (MORE_DEBUG) Slog.d(TAG, "Killing agent host process");
                mActivityManager.killApplicationProcess(app.processName, app.uid);
            } else {
                if (MORE_DEBUG) Slog.d(TAG, "Not killing after operation: " + app.processName);
            }
        } catch (RemoteException e) {
            Slog.d(TAG, "Lost app trying to shut down");
        }
    }

    // Core logic for performing one package's full backup, gathering the tarball from the
    // application and emitting it to the designated OutputStream.

    // Callout from the engine to an interested participant that might need to communicate
    // with the agent prior to asking it to move data
    interface FullBackupPreflight {
        /**
         * Perform the preflight operation necessary for the given package.
         * @param pkg The name of the package being proposed for full-data backup
         * @param agent Live BackupAgent binding to the target app's agent
         * @return BackupTransport.TRANSPORT_OK to proceed with the backup operation,
         *         or one of the other BackupTransport.* error codes as appropriate
         */
        int preflightFullBackup(PackageInfo pkg, IBackupAgent agent);

        long getExpectedSizeOrErrorCode();
    };

    class FullBackupEngine {
        OutputStream mOutput;
        FullBackupPreflight mPreflightHook;
        BackupRestoreTask mTimeoutMonitor;
        IBackupAgent mAgent;
        File mFilesDir;
        File mManifestFile;
        File mMetadataFile;
        boolean mIncludeApks;
        PackageInfo mPkg;
        private final long mQuota;
        private final int mOpToken;

        class FullBackupRunner implements Runnable {
            PackageInfo mPackage;
            byte[] mWidgetData;
            IBackupAgent mAgent;
            ParcelFileDescriptor mPipe;
            int mToken;
            boolean mSendApk;
            boolean mWriteManifest;

            FullBackupRunner(PackageInfo pack, IBackupAgent agent, ParcelFileDescriptor pipe,
                             int token, boolean sendApk, boolean writeManifest, byte[] widgetData)
                    throws IOException {
                mPackage = pack;
                mWidgetData = widgetData;
                mAgent = agent;
                mPipe = ParcelFileDescriptor.dup(pipe.getFileDescriptor());
                mToken = token;
                mSendApk = sendApk;
                mWriteManifest = writeManifest;
            }

            @Override
            public void run() {
                try {
                    FullBackupDataOutput output = new FullBackupDataOutput(mPipe);

                    if (mWriteManifest) {
                        final boolean writeWidgetData = mWidgetData != null;
                        if (MORE_DEBUG) Slog.d(TAG, "Writing manifest for " + mPackage.packageName);
                        writeAppManifest(mPackage, mPackageManager, mManifestFile, mSendApk, writeWidgetData);
                        FullBackup.backupToTar(mPackage.packageName, null, null,
                                mFilesDir.getAbsolutePath(),
                                mManifestFile.getAbsolutePath(),
                                output);
                        mManifestFile.delete();

                        // We only need to write a metadata file if we have widget data to stash
                        if (writeWidgetData) {
                            writeMetadata(mPackage, mMetadataFile, mWidgetData);
                            FullBackup.backupToTar(mPackage.packageName, null, null,
                                    mFilesDir.getAbsolutePath(),
                                    mMetadataFile.getAbsolutePath(),
                                    output);
                            mMetadataFile.delete();
                        }
                    }

                    if (mSendApk) {
                        writeApkToBackup(mPackage, output);
                    }

                    final boolean isSharedStorage =
                            mPackage.packageName.equals(SHARED_BACKUP_AGENT_PACKAGE);
                    final long timeout = isSharedStorage ?
                            TIMEOUT_SHARED_BACKUP_INTERVAL : TIMEOUT_FULL_BACKUP_INTERVAL;

                    if (DEBUG) Slog.d(TAG, "Calling doFullBackup() on " + mPackage.packageName);
                    prepareOperationTimeout(mToken, timeout, mTimeoutMonitor /* in parent class */,
                            OP_TYPE_BACKUP_WAIT);
                    mAgent.doFullBackup(mPipe, mQuota, mToken, mBackupManagerBinder);
                } catch (IOException e) {
                    Slog.e(TAG, "Error running full backup for " + mPackage.packageName);
                } catch (RemoteException e) {
                    Slog.e(TAG, "Remote agent vanished during full backup of "
                            + mPackage.packageName);
                } finally {
                    try {
                        mPipe.close();
                    } catch (IOException e) {}
                }
            }
        }

        FullBackupEngine(OutputStream output, FullBackupPreflight preflightHook, PackageInfo pkg,
                         boolean alsoApks, BackupRestoreTask timeoutMonitor, long quota, int opToken) {
            mOutput = output;
            mPreflightHook = preflightHook;
            mPkg = pkg;
            mIncludeApks = alsoApks;
            mTimeoutMonitor = timeoutMonitor;
            mFilesDir = new File("/data/system");
            mManifestFile = new File(mFilesDir, BACKUP_MANIFEST_FILENAME);
            mMetadataFile = new File(mFilesDir, BACKUP_METADATA_FILENAME);
            mQuota = quota;
            mOpToken = opToken;
        }

        public int preflightCheck() throws RemoteException {
            if (mPreflightHook == null) {
                if (MORE_DEBUG) {
                    Slog.v(TAG, "No preflight check");
                }
                return BackupTransport.TRANSPORT_OK;
            }
            if (initializeAgent()) {
                int result = mPreflightHook.preflightFullBackup(mPkg, mAgent);
                if (MORE_DEBUG) {
                    Slog.v(TAG, "preflight returned " + result);
                }
                return result;
            } else {
                Slog.w(TAG, "Unable to bind to full agent for " + mPkg.packageName);
                return BackupTransport.AGENT_ERROR;
            }
        }

        public int backupOnePackage() throws RemoteException {
            int result = BackupTransport.AGENT_ERROR;

            if (initializeAgent()) {
                ParcelFileDescriptor[] pipes = null;
                try {
                    pipes = ParcelFileDescriptor.createPipe();

                    ApplicationInfo app = mPkg.applicationInfo;
                    final boolean isSharedStorage =
                            mPkg.packageName.equals(SHARED_BACKUP_AGENT_PACKAGE);
                    final boolean sendApk = mIncludeApks
                            && !isSharedStorage
                            && ((app.privateFlags & ApplicationInfo.PRIVATE_FLAG_FORWARD_LOCK) == 0)
                            && ((app.flags & ApplicationInfo.FLAG_SYSTEM) == 0 ||
                            (app.flags & ApplicationInfo.FLAG_UPDATED_SYSTEM_APP) != 0);

                    // TODO: http://b/22388012
                    byte[] widgetBlob = AppWidgetBackupBridge.getWidgetState(mPkg.packageName,
                            UserHandle.USER_SYSTEM);

                    FullBackupRunner runner = new FullBackupRunner(mPkg, mAgent, pipes[1],
                            mOpToken, sendApk, !isSharedStorage, widgetBlob);
                    pipes[1].close();   // the runner has dup'd it
                    pipes[1] = null;
                    Thread t = new Thread(runner, "app-data-runner");
                    t.start();

                    // Now pull data from the app and stuff it into the output
                    routeSocketDataToOutput(pipes[0], mOutput);

                    if (!waitUntilOperationComplete(mOpToken)) {
                        Slog.e(TAG, "Full backup failed on package " + mPkg.packageName);
                    } else {
                        if (MORE_DEBUG) {
                            Slog.d(TAG, "Full package backup success: " + mPkg.packageName);
                        }
                        result = BackupTransport.TRANSPORT_OK;
                    }
                } catch (IOException e) {
                    Slog.e(TAG, "Error backing up " + mPkg.packageName + ": " + e.getMessage());
                    result = BackupTransport.AGENT_ERROR;
                } finally {
                    try {
                        // flush after every package
                        mOutput.flush();
                        if (pipes != null) {
                            if (pipes[0] != null) pipes[0].close();
                            if (pipes[1] != null) pipes[1].close();
                        }
                    } catch (IOException e) {
                        Slog.w(TAG, "Error bringing down backup stack");
                        result = BackupTransport.TRANSPORT_ERROR;
                    }
                }
            } else {
                Slog.w(TAG, "Unable to bind to full agent for " + mPkg.packageName);
            }
            tearDown();
            return result;
        }

        public void sendQuotaExceeded(final long backupDataBytes, final long quotaBytes) {
            if (initializeAgent()) {
                try {
                    mAgent.doQuotaExceeded(backupDataBytes, quotaBytes);
                } catch (RemoteException e) {
                    Slog.e(TAG, "Remote exception while telling agent about quota exceeded");
                }
            }
        }

        private boolean initializeAgent() {
            if (mAgent == null) {
                if (MORE_DEBUG) {
                    Slog.d(TAG, "Binding to full backup agent : " + mPkg.packageName);
                }
                mAgent = bindToAgentSynchronous(mPkg.applicationInfo,
                        ApplicationThreadConstants.BACKUP_MODE_FULL);
            }
            return mAgent != null;
        }

        private void writeApkToBackup(PackageInfo pkg, FullBackupDataOutput output) {
            // Forward-locked apps, system-bundled .apks, etc are filtered out before we get here
            // TODO: handle backing up split APKs
            final String appSourceDir = pkg.applicationInfo.getBaseCodePath();
            final String apkDir = new File(appSourceDir).getParent();
            FullBackup.backupToTar(pkg.packageName, FullBackup.APK_TREE_TOKEN, null,
                    apkDir, appSourceDir, output);

            // TODO: migrate this to SharedStorageBackup, since AID_SYSTEM
            // doesn't have access to external storage.

            // Save associated .obb content if it exists and we did save the apk
            // check for .obb and save those too
            // TODO: http://b/22388012
            final UserEnvironment userEnv = new UserEnvironment(UserHandle.USER_SYSTEM);
            final File obbDir = userEnv.buildExternalStorageAppObbDirs(pkg.packageName)[0];
            if (obbDir != null) {
                if (MORE_DEBUG) Log.i(TAG, "obb dir: " + obbDir.getAbsolutePath());
                File[] obbFiles = obbDir.listFiles();
                if (obbFiles != null) {
                    final String obbDirName = obbDir.getAbsolutePath();
                    for (File obb : obbFiles) {
                        FullBackup.backupToTar(pkg.packageName, FullBackup.OBB_TREE_TOKEN, null,
                                obbDirName, obb.getAbsolutePath(), output);
                    }
                }
            }
        }

        // Widget metadata format. All header entries are strings ending in LF:
        //
        // Version 1 header:
        //     BACKUP_METADATA_VERSION, currently "1"
        //     package name
        //
        // File data (all integers are binary in network byte order)
        // *N: 4 : integer token identifying which metadata blob
        //     4 : integer size of this blob = N
        //     N : raw bytes of this metadata blob
        //
        // Currently understood blobs (always in network byte order):
        //
        //     widgets : metadata token = 0x01FFED01 (BACKUP_WIDGET_METADATA_TOKEN)
        //
        // Unrecognized blobs are *ignored*, not errors.
        private void writeMetadata(PackageInfo pkg, File destination, byte[] widgetData)
                throws IOException {
            StringBuilder b = new StringBuilder(512);
            StringBuilderPrinter printer = new StringBuilderPrinter(b);
            printer.println(Integer.toString(BACKUP_METADATA_VERSION));
            printer.println(pkg.packageName);

            FileOutputStream fout = new FileOutputStream(destination);
            BufferedOutputStream bout = new BufferedOutputStream(fout);
            DataOutputStream out = new DataOutputStream(bout);
            bout.write(b.toString().getBytes());    // bypassing DataOutputStream

            if (widgetData != null && widgetData.length > 0) {
                out.writeInt(BACKUP_WIDGET_METADATA_TOKEN);
                out.writeInt(widgetData.length);
                out.write(widgetData);
            }
            bout.flush();
            out.close();

            // As with the manifest file, guarantee idempotence of the archive metadata
            // for the widget block by using a fixed mtime on the transient file.
            destination.setLastModified(0);
        }

        private void tearDown() {
            if (mPkg != null) {
                tearDownAgentAndKill(mPkg.applicationInfo);
            }
        }
    }

    static void writeAppManifest(PackageInfo pkg, PackageManager packageManager, File manifestFile,
            boolean withApk, boolean withWidgets) throws IOException {
        // Manifest format. All data are strings ending in LF:
        //     BACKUP_MANIFEST_VERSION, currently 1
        //
        // Version 1:
        //     package name
        //     package's versionCode
        //     platform versionCode
        //     getInstallerPackageName() for this package (maybe empty)
        //     boolean: "1" if archive includes .apk; any other string means not
        //     number of signatures == N
        // N*:    signature byte array in ascii format per Signature.toCharsString()
        StringBuilder builder = new StringBuilder(4096);
        StringBuilderPrinter printer = new StringBuilderPrinter(builder);

        printer.println(Integer.toString(BACKUP_MANIFEST_VERSION));
        printer.println(pkg.packageName);
        printer.println(Integer.toString(pkg.versionCode));
        printer.println(Integer.toString(Build.VERSION.SDK_INT));

        String installerName = packageManager.getInstallerPackageName(pkg.packageName);
        printer.println((installerName != null) ? installerName : "");

        printer.println(withApk ? "1" : "0");
        if (pkg.signatures == null) {
            printer.println("0");
        } else {
            printer.println(Integer.toString(pkg.signatures.length));
            for (Signature sig : pkg.signatures) {
                printer.println(sig.toCharsString());
            }
        }

        FileOutputStream outstream = new FileOutputStream(manifestFile);
        outstream.write(builder.toString().getBytes());
        outstream.close();

        // We want the manifest block in the archive stream to be idempotent:
        // each time we generate a backup stream for the app, we want the manifest
        // block to be identical.  The underlying tar mechanism sees it as a file,
        // though, and will propagate its mtime, causing the tar header to vary.
        // Avoid this problem by pinning the mtime to zero.
        manifestFile.setLastModified(0);
    }

    // Generic driver skeleton for full backup operations
    abstract class FullBackupTask implements Runnable {
        IFullBackupRestoreObserver mObserver;

        FullBackupTask(IFullBackupRestoreObserver observer) {
            mObserver = observer;
        }

        // wrappers for observer use
        final void sendStartBackup() {
            if (mObserver != null) {
                try {
                    mObserver.onStartBackup();
                } catch (RemoteException e) {
                    Slog.w(TAG, "full backup observer went away: startBackup");
                    mObserver = null;
                }
            }
        }

        final void sendOnBackupPackage(String name) {
            if (mObserver != null) {
                try {
                    // TODO: use a more user-friendly name string
                    mObserver.onBackupPackage(name);
                } catch (RemoteException e) {
                    Slog.w(TAG, "full backup observer went away: backupPackage");
                    mObserver = null;
                }
            }
        }

        final void sendEndBackup() {
            if (mObserver != null) {
                try {
                    mObserver.onEndBackup();
                } catch (RemoteException e) {
                    Slog.w(TAG, "full backup observer went away: endBackup");
                    mObserver = null;
                }
            }
        }
    }

    boolean deviceIsEncrypted() {
        try {
            return mStorageManager.getEncryptionState()
                     != StorageManager.ENCRYPTION_STATE_NONE
                && mStorageManager.getPasswordType()
                     != StorageManager.CRYPT_TYPE_DEFAULT;
        } catch (Exception e) {
            // If we can't talk to the storagemanager service we have a serious problem; fail
            // "secure" i.e. assuming that the device is encrypted.
            Slog.e(TAG, "Unable to communicate with storagemanager service: " + e.getMessage());
            return true;
        }
    }

    // Full backup task variant used for adb backup
    class PerformAdbBackupTask extends FullBackupTask implements BackupRestoreTask {
        FullBackupEngine mBackupEngine;
        final AtomicBoolean mLatch;

        ParcelFileDescriptor mOutputFile;
        DeflaterOutputStream mDeflater;
        boolean mIncludeApks;
        boolean mIncludeObbs;
        boolean mIncludeShared;
        boolean mDoWidgets;
        boolean mAllApps;
        boolean mIncludeSystem;
        boolean mCompress;
        boolean mKeyValue;
        ArrayList<String> mPackages;
        PackageInfo mCurrentTarget;
        String mCurrentPassword;
        String mEncryptPassword;
        private final int mCurrentOpToken;

        PerformAdbBackupTask(ParcelFileDescriptor fd, IFullBackupRestoreObserver observer,
                boolean includeApks, boolean includeObbs, boolean includeShared, boolean doWidgets,
                String curPassword, String encryptPassword, boolean doAllApps, boolean doSystem,
                boolean doCompress, boolean doKeyValue, String[] packages, AtomicBoolean latch) {
            super(observer);
            mCurrentOpToken = generateRandomIntegerToken();
            mLatch = latch;

            mOutputFile = fd;
            mIncludeApks = includeApks;
            mIncludeObbs = includeObbs;
            mIncludeShared = includeShared;
            mDoWidgets = doWidgets;
            mAllApps = doAllApps;
            mIncludeSystem = doSystem;
            mPackages = (packages == null)
                    ? new ArrayList<String>()
                    : new ArrayList<String>(Arrays.asList(packages));
            mCurrentPassword = curPassword;
            // when backing up, if there is a current backup password, we require that
            // the user use a nonempty encryption password as well.  if one is supplied
            // in the UI we use that, but if the UI was left empty we fall back to the
            // current backup password (which was supplied by the user as well).
            if (encryptPassword == null || "".equals(encryptPassword)) {
                mEncryptPassword = curPassword;
            } else {
                mEncryptPassword = encryptPassword;
            }
            if (MORE_DEBUG) {
                Slog.w(TAG, "Encrypting backup with passphrase=" + mEncryptPassword);
            }
            mCompress = doCompress;
            mKeyValue = doKeyValue;
        }

        void addPackagesToSet(TreeMap<String, PackageInfo> set, List<String> pkgNames) {
            for (String pkgName : pkgNames) {
                if (!set.containsKey(pkgName)) {
                    try {
                        PackageInfo info = mPackageManager.getPackageInfo(pkgName,
                                PackageManager.GET_SIGNATURES);
                        set.put(pkgName, info);
                    } catch (NameNotFoundException e) {
                        Slog.w(TAG, "Unknown package " + pkgName + ", skipping");
                    }
                }
            }
        }

        private OutputStream emitAesBackupHeader(StringBuilder headerbuf,
                OutputStream ofstream) throws Exception {
            // User key will be used to encrypt the master key.
            byte[] newUserSalt = randomBytes(PBKDF2_SALT_SIZE);
            SecretKey userKey = buildPasswordKey(PBKDF_CURRENT, mEncryptPassword, newUserSalt,
                    PBKDF2_HASH_ROUNDS);

            // the master key is random for each backup
            byte[] masterPw = new byte[256 / 8];
            mRng.nextBytes(masterPw);
            byte[] checksumSalt = randomBytes(PBKDF2_SALT_SIZE);

            // primary encryption of the datastream with the random key
            Cipher c = Cipher.getInstance("AES/CBC/PKCS5Padding");
            SecretKeySpec masterKeySpec = new SecretKeySpec(masterPw, "AES");
            c.init(Cipher.ENCRYPT_MODE, masterKeySpec);
            OutputStream finalOutput = new CipherOutputStream(ofstream, c);

            // line 4: name of encryption algorithm
            headerbuf.append(ENCRYPTION_ALGORITHM_NAME);
            headerbuf.append('\n');
            // line 5: user password salt [hex]
            headerbuf.append(byteArrayToHex(newUserSalt));
            headerbuf.append('\n');
            // line 6: master key checksum salt [hex]
            headerbuf.append(byteArrayToHex(checksumSalt));
            headerbuf.append('\n');
            // line 7: number of PBKDF2 rounds used [decimal]
            headerbuf.append(PBKDF2_HASH_ROUNDS);
            headerbuf.append('\n');

            // line 8: IV of the user key [hex]
            Cipher mkC = Cipher.getInstance("AES/CBC/PKCS5Padding");
            mkC.init(Cipher.ENCRYPT_MODE, userKey);

            byte[] IV = mkC.getIV();
            headerbuf.append(byteArrayToHex(IV));
            headerbuf.append('\n');

            // line 9: master IV + key blob, encrypted by the user key [hex].  Blob format:
            //    [byte] IV length = Niv
            //    [array of Niv bytes] IV itself
            //    [byte] master key length = Nmk
            //    [array of Nmk bytes] master key itself
            //    [byte] MK checksum hash length = Nck
            //    [array of Nck bytes] master key checksum hash
            //
            // The checksum is the (master key + checksum salt), run through the
            // stated number of PBKDF2 rounds
            IV = c.getIV();
            byte[] mk = masterKeySpec.getEncoded();
            byte[] checksum = makeKeyChecksum(PBKDF_CURRENT, masterKeySpec.getEncoded(),
                    checksumSalt, PBKDF2_HASH_ROUNDS);

            ByteArrayOutputStream blob = new ByteArrayOutputStream(IV.length + mk.length
                    + checksum.length + 3);
            DataOutputStream mkOut = new DataOutputStream(blob);
            mkOut.writeByte(IV.length);
            mkOut.write(IV);
            mkOut.writeByte(mk.length);
            mkOut.write(mk);
            mkOut.writeByte(checksum.length);
            mkOut.write(checksum);
            mkOut.flush();
            byte[] encryptedMk = mkC.doFinal(blob.toByteArray());
            headerbuf.append(byteArrayToHex(encryptedMk));
            headerbuf.append('\n');

            return finalOutput;
        }

        private void finalizeBackup(OutputStream out) {
            try {
                // A standard 'tar' EOF sequence: two 512-byte blocks of all zeroes.
                byte[] eof = new byte[512 * 2]; // newly allocated == zero filled
                out.write(eof);
            } catch (IOException e) {
                Slog.w(TAG, "Error attempting to finalize backup stream");
            }
        }

        @Override
        public void run() {
            String includeKeyValue = mKeyValue ? ", including key-value backups" : "";
            Slog.i(TAG, "--- Performing adb backup" + includeKeyValue + " ---");

            TreeMap<String, PackageInfo> packagesToBackup = new TreeMap<String, PackageInfo>();
            FullBackupObbConnection obbConnection = new FullBackupObbConnection();
            obbConnection.establish();  // we'll want this later

            sendStartBackup();

            // doAllApps supersedes the package set if any
            if (mAllApps) {
                List<PackageInfo> allPackages = mPackageManager.getInstalledPackages(
                        PackageManager.GET_SIGNATURES);
                for (int i = 0; i < allPackages.size(); i++) {
                    PackageInfo pkg = allPackages.get(i);
                    // Exclude system apps if we've been asked to do so
                    if (mIncludeSystem == true
                            || ((pkg.applicationInfo.flags & ApplicationInfo.FLAG_SYSTEM) == 0)) {
                        packagesToBackup.put(pkg.packageName, pkg);
                    }
                }
            }

            // If we're doing widget state as well, ensure that we have all the involved
            // host & provider packages in the set
            if (mDoWidgets) {
                // TODO: http://b/22388012
                List<String> pkgs =
                        AppWidgetBackupBridge.getWidgetParticipants(UserHandle.USER_SYSTEM);
                if (pkgs != null) {
                    if (MORE_DEBUG) {
                        Slog.i(TAG, "Adding widget participants to backup set:");
                        StringBuilder sb = new StringBuilder(128);
                        sb.append("   ");
                        for (String s : pkgs) {
                            sb.append(' ');
                            sb.append(s);
                        }
                        Slog.i(TAG, sb.toString());
                    }
                    addPackagesToSet(packagesToBackup, pkgs);
                }
            }

            // Now process the command line argument packages, if any. Note that explicitly-
            // named system-partition packages will be included even if includeSystem was
            // set to false.
            if (mPackages != null) {
                addPackagesToSet(packagesToBackup, mPackages);
            }

            // Now we cull any inapplicable / inappropriate packages from the set.  This
            // includes the special shared-storage agent package; we handle that one
            // explicitly at the end of the backup pass. Packages supporting key-value backup are
            // added to their own queue, and handled after packages supporting fullbackup.
            ArrayList<PackageInfo> keyValueBackupQueue = new ArrayList<>();
            Iterator<Entry<String, PackageInfo>> iter = packagesToBackup.entrySet().iterator();
            while (iter.hasNext()) {
                PackageInfo pkg = iter.next().getValue();
                if (!appIsEligibleForBackup(pkg.applicationInfo, mPackageManager)
                        || appIsStopped(pkg.applicationInfo)) {
                    iter.remove();
                    if (DEBUG) {
                        Slog.i(TAG, "Package " + pkg.packageName
                                + " is not eligible for backup, removing.");
                    }
                } else if (appIsKeyValueOnly(pkg)) {
                    iter.remove();
                    if (DEBUG) {
                        Slog.i(TAG, "Package " + pkg.packageName
                                + " is key-value.");
                    }
                    keyValueBackupQueue.add(pkg);
                }
            }

            // flatten the set of packages now so we can explicitly control the ordering
            ArrayList<PackageInfo> backupQueue =
                    new ArrayList<PackageInfo>(packagesToBackup.values());
            FileOutputStream ofstream = new FileOutputStream(mOutputFile.getFileDescriptor());
            OutputStream out = null;

            PackageInfo pkg = null;
            try {
                boolean encrypting = (mEncryptPassword != null && mEncryptPassword.length() > 0);

                // Only allow encrypted backups of encrypted devices
                if (deviceIsEncrypted() && !encrypting) {
                    Slog.e(TAG, "Unencrypted backup of encrypted device; aborting");
                    return;
                }

                OutputStream finalOutput = ofstream;

                // Verify that the given password matches the currently-active
                // backup password, if any
                if (!backupPasswordMatches(mCurrentPassword)) {
                    if (DEBUG) Slog.w(TAG, "Backup password mismatch; aborting");
                    return;
                }

                // Write the global file header.  All strings are UTF-8 encoded; lines end
                // with a '\n' byte.  Actual backup data begins immediately following the
                // final '\n'.
                //
                // line 1: "ANDROID BACKUP"
                // line 2: backup file format version, currently "5"
                // line 3: compressed?  "0" if not compressed, "1" if compressed.
                // line 4: name of encryption algorithm [currently only "none" or "AES-256"]
                //
                // When line 4 is not "none", then additional header data follows:
                //
                // line 5: user password salt [hex]
                // line 6: master key checksum salt [hex]
                // line 7: number of PBKDF2 rounds to use (same for user & master) [decimal]
                // line 8: IV of the user key [hex]
                // line 9: master key blob [hex]
                //     IV of the master key, master key itself, master key checksum hash
                //
                // The master key checksum is the master key plus its checksum salt, run through
                // 10k rounds of PBKDF2.  This is used to verify that the user has supplied the
                // correct password for decrypting the archive:  the master key decrypted from
                // the archive using the user-supplied password is also run through PBKDF2 in
                // this way, and if the result does not match the checksum as stored in the
                // archive, then we know that the user-supplied password does not match the
                // archive's.
                StringBuilder headerbuf = new StringBuilder(1024);

                headerbuf.append(BACKUP_FILE_HEADER_MAGIC);
                headerbuf.append(BACKUP_FILE_VERSION); // integer, no trailing \n
                headerbuf.append(mCompress ? "\n1\n" : "\n0\n");

                try {
                    // Set up the encryption stage if appropriate, and emit the correct header
                    if (encrypting) {
                        finalOutput = emitAesBackupHeader(headerbuf, finalOutput);
                    } else {
                        headerbuf.append("none\n");
                    }

                    byte[] header = headerbuf.toString().getBytes("UTF-8");
                    ofstream.write(header);

                    // Set up the compression stage feeding into the encryption stage (if any)
                    if (mCompress) {
                        Deflater deflater = new Deflater(Deflater.BEST_COMPRESSION);
                        finalOutput = new DeflaterOutputStream(finalOutput, deflater, true);
                    }

                    out = finalOutput;
                } catch (Exception e) {
                    // Should never happen!
                    Slog.e(TAG, "Unable to emit archive header", e);
                    return;
                }

                // Shared storage if requested
                if (mIncludeShared) {
                    try {
                        pkg = mPackageManager.getPackageInfo(SHARED_BACKUP_AGENT_PACKAGE, 0);
                        backupQueue.add(pkg);
                    } catch (NameNotFoundException e) {
                        Slog.e(TAG, "Unable to find shared-storage backup handler");
                    }
                }

                // Now actually run the constructed backup sequence for full backup
                int N = backupQueue.size();
                for (int i = 0; i < N; i++) {
                    pkg = backupQueue.get(i);
                    if (DEBUG) {
                        Slog.i(TAG,"--- Performing full backup for package " + pkg.packageName
                                + " ---");
                    }
                    final boolean isSharedStorage =
                            pkg.packageName.equals(SHARED_BACKUP_AGENT_PACKAGE);

                    mBackupEngine = new FullBackupEngine(out, null, pkg, mIncludeApks, this, Long.MAX_VALUE, mCurrentOpToken);
                    sendOnBackupPackage(isSharedStorage ? "Shared storage" : pkg.packageName);

                    // Don't need to check preflight result as there is no preflight hook.
                    mCurrentTarget = pkg;
                    mBackupEngine.backupOnePackage();

                    // after the app's agent runs to handle its private filesystem
                    // contents, back up any OBB content it has on its behalf.
                    if (mIncludeObbs) {
                        boolean obbOkay = obbConnection.backupObbs(pkg, out);
                        if (!obbOkay) {
                            throw new RuntimeException("Failure writing OBB stack for " + pkg);
                        }
                    }
                }
                // And for key-value backup if enabled
                if (mKeyValue) {
                    for (PackageInfo keyValuePackage : keyValueBackupQueue) {
                        if (DEBUG) {
                            Slog.i(TAG, "--- Performing key-value backup for package "
                                    + keyValuePackage.packageName + " ---");
                        }
                        KeyValueAdbBackupEngine kvBackupEngine =
                                new KeyValueAdbBackupEngine(out, keyValuePackage,
                                        BackupManagerService.this,
                                        mPackageManager, mBaseStateDir, mDataDir);
                        sendOnBackupPackage(keyValuePackage.packageName);
                        kvBackupEngine.backupOnePackage();
                    }
                }

                // Done!
                finalizeBackup(out);
            } catch (RemoteException e) {
                Slog.e(TAG, "App died during full backup");
            } catch (Exception e) {
                Slog.e(TAG, "Internal exception during full backup", e);
            } finally {
                try {
                    if (out != null) {
                        out.flush();
                        out.close();
                    }
                    mOutputFile.close();
                } catch (IOException e) {
                    /* nothing we can do about this */
                }
                synchronized (mLatch) {
                    mLatch.set(true);
                    mLatch.notifyAll();
                }
                sendEndBackup();
                obbConnection.tearDown();
                if (DEBUG) Slog.d(TAG, "Full backup pass complete.");
                mWakelock.release();
            }
        }

        // BackupRestoreTask methods, used for timeout handling
        @Override
        public void execute() {
            // Unused
        }

        @Override
        public void operationComplete(long result) {
            // Unused
        }

        @Override
        public void handleCancel(boolean cancelAll) {
            final PackageInfo target = mCurrentTarget;
            if (DEBUG) {
                Slog.w(TAG, "adb backup cancel of " + target);
            }
            if (target != null) {
                tearDownAgentAndKill(mCurrentTarget.applicationInfo);
            }
            removeOperation(mCurrentOpToken);
        }
    }

    /**
     * Full backup task extension used for transport-oriented operation.
     *
     * Flow:
     * For each requested package:
     *     - Spin off a new SinglePackageBackupRunner (mBackupRunner) for the current package.
     *     - Wait until preflight is complete. (mBackupRunner.getPreflightResultBlocking())
     *     - If preflight data size is within limit, start reading data from agent pipe and writing
     *       to transport pipe. While there is data to send, call transport.sendBackupData(int) to
     *       tell the transport how many bytes to expect on its pipe.
     *     - After sending all data, call transport.finishBackup() if things went well. And
     *       transport.cancelFullBackup() otherwise.
     *
     * Interactions with mCurrentOperations:
     *     - An entry for this object is added to mCurrentOperations for the entire lifetime of this
     *       object. Used to cancel the operation.
     *     - SinglePackageBackupRunner and SinglePackageBackupPreflight will put ephemeral entries
     *       to get timeouts or operation complete callbacks.
     *
     * Handling cancels:
     *     - The contract we provide is that the task won't interact with the transport after
     *       handleCancel() is done executing.
     *     - This task blocks at 3 points: 1. Preflight result check 2. Reading on agent side pipe
     *       and 3. Get backup result from mBackupRunner.
     *     - Bubbling up handleCancel to mBackupRunner handles all 3: 1. Calls handleCancel on the
     *       preflight operation which counts down on the preflight latch. 2. Tears down the agent,
     *       so read() returns -1. 3. Notifies mCurrentOpLock which unblocks
     *       mBackupRunner.getBackupResultBlocking().
     */
    class PerformFullTransportBackupTask extends FullBackupTask implements BackupRestoreTask {
        static final String TAG = "PFTBT";

        private final Object mCancelLock = new Object();

        ArrayList<PackageInfo> mPackages;
        PackageInfo mCurrentPackage;
        boolean mUpdateSchedule;
        CountDownLatch mLatch;
        FullBackupJob mJob;             // if a scheduled job needs to be finished afterwards
        IBackupObserver mBackupObserver;
        IBackupManagerMonitor mMonitor;
        boolean mUserInitiated;
        private volatile IBackupTransport mTransport;
        SinglePackageBackupRunner mBackupRunner;
        private final int mBackupRunnerOpToken;

        // This is true when a backup operation for some package is in progress.
        private volatile boolean mIsDoingBackup;
        private volatile boolean mCancelAll;
        private final int mCurrentOpToken;

        PerformFullTransportBackupTask(IFullBackupRestoreObserver observer,
                String[] whichPackages, boolean updateSchedule,
                FullBackupJob runningJob, CountDownLatch latch, IBackupObserver backupObserver,
                IBackupManagerMonitor monitor, boolean userInitiated) {
            super(observer);
            mUpdateSchedule = updateSchedule;
            mLatch = latch;
            mJob = runningJob;
            mPackages = new ArrayList<PackageInfo>(whichPackages.length);
            mBackupObserver = backupObserver;
            mMonitor = monitor;
            mUserInitiated = userInitiated;
            mCurrentOpToken = generateRandomIntegerToken();
            mBackupRunnerOpToken = generateRandomIntegerToken();

            if (isBackupOperationInProgress()) {
                if (DEBUG) {
                    Slog.d(TAG, "Skipping full backup. A backup is already in progress.");
                }
                mCancelAll = true;
                return;
            }

            registerTask();

            for (String pkg : whichPackages) {
                try {
                    PackageInfo info = mPackageManager.getPackageInfo(pkg,
                            PackageManager.GET_SIGNATURES);
                    mCurrentPackage = info;
                    if (!appIsEligibleForBackup(info.applicationInfo, mPackageManager)) {
                        // Cull any packages that have indicated that backups are not permitted,
                        // that run as system-domain uids but do not define their own backup agents,
                        // as well as any explicit mention of the 'special' shared-storage agent
                        // package (we handle that one at the end).
                        if (MORE_DEBUG) {
                            Slog.d(TAG, "Ignoring ineligible package " + pkg);
                        }
                        mMonitor = monitorEvent(mMonitor,
                                BackupManagerMonitor.LOG_EVENT_ID_PACKAGE_INELIGIBLE,
                                mCurrentPackage,
                                BackupManagerMonitor.LOG_EVENT_CATEGORY_BACKUP_MANAGER_POLICY,
                                null);
                        sendBackupOnPackageResult(mBackupObserver, pkg,
                            BackupManager.ERROR_BACKUP_NOT_ALLOWED);
                        continue;
                    } else if (!appGetsFullBackup(info)) {
                        // Cull any packages that are found in the queue but now aren't supposed
                        // to get full-data backup operations.
                        if (MORE_DEBUG) {
                            Slog.d(TAG, "Ignoring full-data backup of key/value participant "
                                    + pkg);
                        }
                        mMonitor = monitorEvent(mMonitor,
                                BackupManagerMonitor.LOG_EVENT_ID_PACKAGE_KEY_VALUE_PARTICIPANT,
                                mCurrentPackage,
                                BackupManagerMonitor.LOG_EVENT_CATEGORY_BACKUP_MANAGER_POLICY,
                                null);
                        sendBackupOnPackageResult(mBackupObserver, pkg,
                                BackupManager.ERROR_BACKUP_NOT_ALLOWED);
                        continue;
                    } else if (appIsStopped(info.applicationInfo)) {
                        // Cull any packages in the 'stopped' state: they've either just been
                        // installed or have explicitly been force-stopped by the user.  In both
                        // cases we do not want to launch them for backup.
                        if (MORE_DEBUG) {
                            Slog.d(TAG, "Ignoring stopped package " + pkg);
                        }
                        mMonitor = monitorEvent(mMonitor,
                                BackupManagerMonitor.LOG_EVENT_ID_PACKAGE_STOPPED,
                                mCurrentPackage,
                                BackupManagerMonitor.LOG_EVENT_CATEGORY_BACKUP_MANAGER_POLICY,
                                null);
                        sendBackupOnPackageResult(mBackupObserver, pkg,
                                BackupManager.ERROR_BACKUP_NOT_ALLOWED);
                        continue;
                    }
                    mPackages.add(info);
                } catch (NameNotFoundException e) {
                    Slog.i(TAG, "Requested package " + pkg + " not found; ignoring");
                    mMonitor = monitorEvent(mMonitor,
                            BackupManagerMonitor.LOG_EVENT_ID_PACKAGE_NOT_FOUND,
                            mCurrentPackage,
                            BackupManagerMonitor.LOG_EVENT_CATEGORY_BACKUP_MANAGER_POLICY,
                            null);
                }
            }
        }

        private void registerTask() {
            synchronized (mCurrentOpLock) {
                Slog.d(TAG, "backupmanager pftbt token=" + Integer.toHexString(mCurrentOpToken));
                mCurrentOperations.put(mCurrentOpToken, new Operation(OP_PENDING, this,
                        OP_TYPE_BACKUP));
            }
        }

        private void unregisterTask() {
            removeOperation(mCurrentOpToken);
        }

        @Override
        public void execute() {
            // Nothing to do.
        }

        @Override
        public void handleCancel(boolean cancelAll) {
            synchronized (mCancelLock) {
                // We only support 'cancelAll = true' case for this task. Cancelling of a single package

                // due to timeout is handled by SinglePackageBackupRunner and SinglePackageBackupPreflight.

                if (!cancelAll) {
                    Slog.wtf(TAG, "Expected cancelAll to be true.");
                }

                if (mCancelAll) {
                    Slog.d(TAG, "Ignoring duplicate cancel call.");
                    return;
                }

                mCancelAll = true;
                if (mIsDoingBackup) {
                    BackupManagerService.this.handleCancel(mBackupRunnerOpToken, cancelAll);
                    try {
                        mTransport.cancelFullBackup();
                    } catch (RemoteException e) {
                        Slog.w(TAG, "Error calling cancelFullBackup() on transport: " + e);
                        // Can't do much.
                    }
                }
            }
        }

        @Override
        public void operationComplete(long result) {
            // Nothing to do.
        }

        @Override
        public void run() {

            // data from the app, passed to us for bridging to the transport
            ParcelFileDescriptor[] enginePipes = null;

            // Pipe through which we write data to the transport
            ParcelFileDescriptor[] transportPipes = null;

            long backoff = 0;
            int backupRunStatus = BackupManager.SUCCESS;

            try {
                if (!mEnabled || !mProvisioned) {
                    // Backups are globally disabled, so don't proceed.
                    if (DEBUG) {
                        Slog.i(TAG, "full backup requested but enabled=" + mEnabled
                                + " provisioned=" + mProvisioned + "; ignoring");
                    }
                    int monitoringEvent;
                    if (mProvisioned) {
                        monitoringEvent = BackupManagerMonitor.LOG_EVENT_ID_BACKUP_DISABLED;
                    } else {
                        monitoringEvent = BackupManagerMonitor.LOG_EVENT_ID_DEVICE_NOT_PROVISIONED;
                    }
                    mMonitor = monitorEvent(mMonitor, monitoringEvent, null,
                            BackupManagerMonitor.LOG_EVENT_CATEGORY_BACKUP_MANAGER_POLICY, null);
                    mUpdateSchedule = false;
                    backupRunStatus = BackupManager.ERROR_BACKUP_NOT_ALLOWED;
                    return;
                }

                mTransport = mTransportManager.getCurrentTransportBinder();
                if (mTransport == null) {
                    Slog.w(TAG, "Transport not present; full data backup not performed");
                    backupRunStatus = BackupManager.ERROR_TRANSPORT_ABORTED;
                    mMonitor = monitorEvent(mMonitor,
                            BackupManagerMonitor.LOG_EVENT_ID_PACKAGE_TRANSPORT_NOT_PRESENT,
                            mCurrentPackage, BackupManagerMonitor.LOG_EVENT_CATEGORY_TRANSPORT,
                            null);
                    return;
                }

                // Set up to send data to the transport
                final int N = mPackages.size();
                final byte[] buffer = new byte[8192];
                for (int i = 0; i < N; i++) {
                    mBackupRunner = null;
                    PackageInfo currentPackage = mPackages.get(i);
                    String packageName = currentPackage.packageName;
                    if (DEBUG) {
                        Slog.i(TAG, "Initiating full-data transport backup of " + packageName
                                + " token: " + mCurrentOpToken);
                    }
                    EventLog.writeEvent(EventLogTags.FULL_BACKUP_PACKAGE, packageName);

                    transportPipes = ParcelFileDescriptor.createPipe();

                    // Tell the transport the data's coming
                    int flags = mUserInitiated ? BackupTransport.FLAG_USER_INITIATED : 0;
                    int backupPackageStatus;
                    long quota = Long.MAX_VALUE;
                    synchronized (mCancelLock) {
                        if (mCancelAll) {
                            break;
                        }
                        backupPackageStatus = mTransport.performFullBackup(currentPackage,
                                transportPipes[0], flags);

                        if (backupPackageStatus == BackupTransport.TRANSPORT_OK) {
                            quota = mTransport.getBackupQuota(currentPackage.packageName,
                                    true /* isFullBackup */);
                            // Now set up the backup engine / data source end of things
                            enginePipes = ParcelFileDescriptor.createPipe();
                            mBackupRunner =
                                    new SinglePackageBackupRunner(enginePipes[1], currentPackage,
                                            mTransport, quota, mBackupRunnerOpToken);
                            // The runner dup'd the pipe half, so we close it here
                            enginePipes[1].close();
                            enginePipes[1] = null;

                            mIsDoingBackup = true;
                        }
                    }
                    if (backupPackageStatus == BackupTransport.TRANSPORT_OK) {

                        // The transport has its own copy of the read end of the pipe,
                        // so close ours now
                        transportPipes[0].close();
                        transportPipes[0] = null;

                        // Spin off the runner to fetch the app's data and pipe it
                        // into the engine pipes
                        (new Thread(mBackupRunner, "package-backup-bridge")).start();

                        // Read data off the engine pipe and pass it to the transport
                        // pipe until we hit EOD on the input stream.  We do not take
                        // close() responsibility for these FDs into these stream wrappers.
                        FileInputStream in = new FileInputStream(
                                enginePipes[0].getFileDescriptor());
                        FileOutputStream out = new FileOutputStream(
                                transportPipes[1].getFileDescriptor());
                        long totalRead = 0;
                        final long preflightResult = mBackupRunner.getPreflightResultBlocking();
                        // Preflight result is negative if some error happened on preflight.
                        if (preflightResult < 0) {
                            if (MORE_DEBUG) {
                                Slog.d(TAG, "Backup error after preflight of package "
                                        + packageName + ": " + preflightResult
                                        + ", not running backup.");
                            }
                            mMonitor = monitorEvent(mMonitor,
                                    BackupManagerMonitor.LOG_EVENT_ID_ERROR_PREFLIGHT,
                                    mCurrentPackage,
                                    BackupManagerMonitor.LOG_EVENT_CATEGORY_BACKUP_MANAGER_POLICY,
                                    putMonitoringExtra(null,
                                            BackupManagerMonitor.EXTRA_LOG_PREFLIGHT_ERROR,
                                            preflightResult));
                            backupPackageStatus = (int) preflightResult;
                        } else {
                            int nRead = 0;
                            do {
                                nRead = in.read(buffer);
                                if (MORE_DEBUG) {
                                    Slog.v(TAG, "in.read(buffer) from app: " + nRead);
                                }
                                if (nRead > 0) {
                                    out.write(buffer, 0, nRead);
                                    synchronized (mCancelLock) {
                                        if (!mCancelAll) {
                                            backupPackageStatus = mTransport.sendBackupData(nRead);
                                        }
                                    }
                                    totalRead += nRead;
                                    if (mBackupObserver != null && preflightResult > 0) {
                                        sendBackupOnUpdate(mBackupObserver, packageName,
                                                new BackupProgress(preflightResult, totalRead));
                                    }
                                }
                            } while (nRead > 0
                                    && backupPackageStatus == BackupTransport.TRANSPORT_OK);
                            // Despite preflight succeeded, package still can hit quota on flight.
                            if (backupPackageStatus == BackupTransport.TRANSPORT_QUOTA_EXCEEDED) {
                                Slog.w(TAG, "Package hit quota limit in-flight " + packageName
                                        + ": " + totalRead + " of " + quota);
                                mMonitor = monitorEvent(mMonitor,
                                        BackupManagerMonitor.LOG_EVENT_ID_QUOTA_HIT_PREFLIGHT,
                                        mCurrentPackage,
                                        BackupManagerMonitor.LOG_EVENT_CATEGORY_TRANSPORT,
                                        null);
                                mBackupRunner.sendQuotaExceeded(totalRead, quota);
                            }
                        }

                        final int backupRunnerResult = mBackupRunner.getBackupResultBlocking();

                        synchronized (mCancelLock) {
                            mIsDoingBackup = false;
                            // If mCancelCurrent is true, we have already called cancelFullBackup().
                            if (!mCancelAll) {
                                if (backupRunnerResult == BackupTransport.TRANSPORT_OK) {
                                    // If we were otherwise in a good state, now interpret the final
                                    // result based on what finishBackup() returns.  If we're in a
                                    // failure case already, preserve that result and ignore whatever
                                    // finishBackup() reports.
                                    final int finishResult = mTransport.finishBackup();
                                    if (backupPackageStatus == BackupTransport.TRANSPORT_OK) {
                                        backupPackageStatus = finishResult;
                                    }
                                } else {
                                    mTransport.cancelFullBackup();
                                }
                            }
                        }

                        // A transport-originated error here means that we've hit an error that the
                        // runner doesn't know about, so it's still moving data but we're pulling the
                        // rug out from under it.  Don't ask for its result:  we already know better
                        // and we'll hang if we block waiting for it, since it relies on us to
                        // read back the data it's writing into the engine.  Just proceed with
                        // a graceful failure.  The runner/engine mechanism will tear itself
                        // down cleanly when we close the pipes from this end.  Transport-level
                        // errors take precedence over agent/app-specific errors for purposes of
                        // determining our course of action.
                        if (backupPackageStatus == BackupTransport.TRANSPORT_OK) {
                            // We still could fail in backup runner thread.
                            if (backupRunnerResult != BackupTransport.TRANSPORT_OK) {
                                // If there was an error in runner thread and
                                // not TRANSPORT_ERROR here, overwrite it.
                                backupPackageStatus = backupRunnerResult;
                            }
                        } else {
                            if (MORE_DEBUG) {
                                Slog.i(TAG, "Transport-level failure; cancelling agent work");
                            }
                        }

                        if (MORE_DEBUG) {
                            Slog.i(TAG, "Done delivering backup data: result="
                                    + backupPackageStatus);
                        }

                        if (backupPackageStatus != BackupTransport.TRANSPORT_OK) {
                            Slog.e(TAG, "Error " + backupPackageStatus + " backing up "
                                    + packageName);
                        }

                        // Also ask the transport how long it wants us to wait before
                        // moving on to the next package, if any.
                        backoff = mTransport.requestFullBackupTime();
                        if (DEBUG_SCHEDULING) {
                            Slog.i(TAG, "Transport suggested backoff=" + backoff);
                        }

                    }

                    // Roll this package to the end of the backup queue if we're
                    // in a queue-driven mode (regardless of success/failure)
                    if (mUpdateSchedule) {
                        enqueueFullBackup(packageName, System.currentTimeMillis());
                    }

                    if (backupPackageStatus == BackupTransport.TRANSPORT_PACKAGE_REJECTED) {
                        sendBackupOnPackageResult(mBackupObserver, packageName,
                                BackupManager.ERROR_TRANSPORT_PACKAGE_REJECTED);
                        if (DEBUG) {
                            Slog.i(TAG, "Transport rejected backup of " + packageName
                                    + ", skipping");
                        }
                        EventLog.writeEvent(EventLogTags.FULL_BACKUP_AGENT_FAILURE, packageName,
                                "transport rejected");
                        // This failure state can come either a-priori from the transport, or
                        // from the preflight pass.  If we got as far as preflight, we now need
                        // to tear down the target process.
                        if (mBackupRunner != null) {
                            tearDownAgentAndKill(currentPackage.applicationInfo);
                        }
                        // ... and continue looping.
                    } else if (backupPackageStatus == BackupTransport.TRANSPORT_QUOTA_EXCEEDED) {
                        sendBackupOnPackageResult(mBackupObserver, packageName,
                                BackupManager.ERROR_TRANSPORT_QUOTA_EXCEEDED);
                        if (DEBUG) {
                            Slog.i(TAG, "Transport quota exceeded for package: " + packageName);
                            EventLog.writeEvent(EventLogTags.FULL_BACKUP_QUOTA_EXCEEDED,
                                    packageName);
                        }
                        tearDownAgentAndKill(currentPackage.applicationInfo);
                        // Do nothing, clean up, and continue looping.
                    } else if (backupPackageStatus == BackupTransport.AGENT_ERROR) {
                        sendBackupOnPackageResult(mBackupObserver, packageName,
                                BackupManager.ERROR_AGENT_FAILURE);
                        Slog.w(TAG, "Application failure for package: " + packageName);
                        EventLog.writeEvent(EventLogTags.BACKUP_AGENT_FAILURE, packageName);
                        tearDownAgentAndKill(currentPackage.applicationInfo);
                        // Do nothing, clean up, and continue looping.
                    } else if (backupPackageStatus == BackupManager.ERROR_BACKUP_CANCELLED) {
                        sendBackupOnPackageResult(mBackupObserver, packageName,
                                BackupManager.ERROR_BACKUP_CANCELLED);
                        Slog.w(TAG, "Backup cancelled. package=" + packageName +
                                ", cancelAll=" + mCancelAll);
                        EventLog.writeEvent(EventLogTags.FULL_BACKUP_CANCELLED, packageName);
                        tearDownAgentAndKill(currentPackage.applicationInfo);
                        // Do nothing, clean up, and continue looping.
                    } else if (backupPackageStatus != BackupTransport.TRANSPORT_OK) {
                        sendBackupOnPackageResult(mBackupObserver, packageName,
                            BackupManager.ERROR_TRANSPORT_ABORTED);
                        Slog.w(TAG, "Transport failed; aborting backup: " + backupPackageStatus);
                        EventLog.writeEvent(EventLogTags.FULL_BACKUP_TRANSPORT_FAILURE);
                        // Abort entire backup pass.
                        backupRunStatus = BackupManager.ERROR_TRANSPORT_ABORTED;
                        tearDownAgentAndKill(currentPackage.applicationInfo);
                        return;
                    } else {
                        // Success!
                        sendBackupOnPackageResult(mBackupObserver, packageName,
                                BackupManager.SUCCESS);
                        EventLog.writeEvent(EventLogTags.FULL_BACKUP_SUCCESS, packageName);
                        logBackupComplete(packageName);
                    }
                    cleanUpPipes(transportPipes);
                    cleanUpPipes(enginePipes);
                    if (currentPackage.applicationInfo != null) {
                        Slog.i(TAG, "Unbinding agent in " + packageName);
                        addBackupTrace("unbinding " + packageName);
                        try {
                            mActivityManager.unbindBackupAgent(currentPackage.applicationInfo);
                        } catch (RemoteException e) { /* can't happen; activity manager is local */ }
                    }
                }
            } catch (Exception e) {
                backupRunStatus = BackupManager.ERROR_TRANSPORT_ABORTED;
                Slog.w(TAG, "Exception trying full transport backup", e);
                mMonitor = monitorEvent(mMonitor,
                        BackupManagerMonitor.LOG_EVENT_ID_EXCEPTION_FULL_BACKUP,
                        mCurrentPackage,
                        BackupManagerMonitor.LOG_EVENT_CATEGORY_BACKUP_MANAGER_POLICY,
                        putMonitoringExtra(null,
                                BackupManagerMonitor.EXTRA_LOG_EXCEPTION_FULL_BACKUP,
                                Log.getStackTraceString(e)));

            } finally {

                if (mCancelAll) {
                    backupRunStatus = BackupManager.ERROR_BACKUP_CANCELLED;
                }

                if (DEBUG) {
                    Slog.i(TAG, "Full backup completed with status: " + backupRunStatus);
                }
                sendBackupFinished(mBackupObserver, backupRunStatus);

                cleanUpPipes(transportPipes);
                cleanUpPipes(enginePipes);

                unregisterTask();

                if (mJob != null) {
                    mJob.finishBackupPass();
                }

                synchronized (mQueueLock) {
                    mRunningFullBackupTask = null;
                }

                mLatch.countDown();

                // Now that we're actually done with schedule-driven work, reschedule
                // the next pass based on the new queue state.
                if (mUpdateSchedule) {
                    scheduleNextFullBackupJob(backoff);
                }

                Slog.i(BackupManagerService.TAG, "Full data backup pass finished.");
                mWakelock.release();
            }
        }

        void cleanUpPipes(ParcelFileDescriptor[] pipes) {
            if (pipes != null) {
                if (pipes[0] != null) {
                    ParcelFileDescriptor fd = pipes[0];
                    pipes[0] = null;
                    try {
                        fd.close();
                    } catch (IOException e) {
                        Slog.w(TAG, "Unable to close pipe!");
                    }
                }
                if (pipes[1] != null) {
                    ParcelFileDescriptor fd = pipes[1];
                    pipes[1] = null;
                    try {
                        fd.close();
                    } catch (IOException e) {
                        Slog.w(TAG, "Unable to close pipe!");
                    }
                }
            }
        }

        // Run the backup and pipe it back to the given socket -- expects to run on
        // a standalone thread.  The  runner owns this half of the pipe, and closes
        // it to indicate EOD to the other end.
        class SinglePackageBackupPreflight implements BackupRestoreTask, FullBackupPreflight {
            final AtomicLong mResult = new AtomicLong(BackupTransport.AGENT_ERROR);
            final CountDownLatch mLatch = new CountDownLatch(1);
            final IBackupTransport mTransport;
            final long mQuota;
            private final int mCurrentOpToken;

            SinglePackageBackupPreflight(IBackupTransport transport, long quota, int currentOpToken) {
                mTransport = transport;
                mQuota = quota;
                mCurrentOpToken = currentOpToken;
            }

            @Override
            public int preflightFullBackup(PackageInfo pkg, IBackupAgent agent) {
                int result;
                try {
                    prepareOperationTimeout(mCurrentOpToken, TIMEOUT_FULL_BACKUP_INTERVAL,
                            this, OP_TYPE_BACKUP_WAIT);
                    addBackupTrace("preflighting");
                    if (MORE_DEBUG) {
                        Slog.d(TAG, "Preflighting full payload of " + pkg.packageName);
                    }
                    agent.doMeasureFullBackup(mQuota, mCurrentOpToken, mBackupManagerBinder);

                    // Now wait to get our result back.  If this backstop timeout is reached without
                    // the latch being thrown, flow will continue as though a result or "normal"
                    // timeout had been produced.  In case of a real backstop timeout, mResult
                    // will still contain the value it was constructed with, AGENT_ERROR, which
                    // intentionaly falls into the "just report failure" code.
                    mLatch.await(TIMEOUT_FULL_BACKUP_INTERVAL, TimeUnit.MILLISECONDS);

                    long totalSize = mResult.get();
                    // If preflight timed out, mResult will contain error code as int.
                    if (totalSize < 0) {
                        return (int) totalSize;
                    }
                    if (MORE_DEBUG) {
                        Slog.v(TAG, "Got preflight response; size=" + totalSize);
                    }

                    result = mTransport.checkFullBackupSize(totalSize);
                    if (result == BackupTransport.TRANSPORT_QUOTA_EXCEEDED) {
                        if (MORE_DEBUG) {
                            Slog.d(TAG, "Package hit quota limit on preflight " +
                                    pkg.packageName + ": " + totalSize + " of " + mQuota);
                        }
                        agent.doQuotaExceeded(totalSize, mQuota);
                    }
                } catch (Exception e) {
                    Slog.w(TAG, "Exception preflighting " + pkg.packageName + ": " + e.getMessage());
                    result = BackupTransport.AGENT_ERROR;
                }
                return result;
            }

            @Override
            public void execute() {
                // Unused.
            }

            @Override
            public void operationComplete(long result) {
                // got the callback, and our preflightFullBackup() method is waiting for the result
                if (MORE_DEBUG) {
                    Slog.i(TAG, "Preflight op complete, result=" + result);
                }
                mResult.set(result);
                mLatch.countDown();
                removeOperation(mCurrentOpToken);
            }

            @Override
            public void handleCancel(boolean cancelAll) {
                if (MORE_DEBUG) {
                    Slog.i(TAG, "Preflight cancelled; failing");
                }
                mResult.set(BackupTransport.AGENT_ERROR);
                mLatch.countDown();
                removeOperation(mCurrentOpToken);
            }

            @Override
            public long getExpectedSizeOrErrorCode() {
                try {
                    mLatch.await(TIMEOUT_FULL_BACKUP_INTERVAL, TimeUnit.MILLISECONDS);
                    return mResult.get();
                } catch (InterruptedException e) {
                    return BackupTransport.NO_MORE_DATA;
                }
            }
        }

        class SinglePackageBackupRunner implements Runnable, BackupRestoreTask {
            final ParcelFileDescriptor mOutput;
            final PackageInfo mTarget;
            final SinglePackageBackupPreflight mPreflight;
            final CountDownLatch mPreflightLatch;
            final CountDownLatch mBackupLatch;
            private final int mCurrentOpToken;
            private final int mEphemeralToken;
            private FullBackupEngine mEngine;
            private volatile int mPreflightResult;
            private volatile int mBackupResult;
            private final long mQuota;
            private volatile boolean mIsCancelled;

            SinglePackageBackupRunner(ParcelFileDescriptor output, PackageInfo target,
                    IBackupTransport transport, long quota, int currentOpToken) throws IOException {
                mOutput = ParcelFileDescriptor.dup(output.getFileDescriptor());
                mTarget = target;
                mCurrentOpToken = currentOpToken;
                mEphemeralToken = generateRandomIntegerToken();
                mPreflight = new SinglePackageBackupPreflight(transport, quota, mEphemeralToken);
                mPreflightLatch = new CountDownLatch(1);
                mBackupLatch = new CountDownLatch(1);
                mPreflightResult = BackupTransport.AGENT_ERROR;
                mBackupResult = BackupTransport.AGENT_ERROR;
                mQuota = quota;
                registerTask();
            }

            void registerTask() {
                synchronized (mCurrentOpLock) {
                    mCurrentOperations.put(mCurrentOpToken, new Operation(OP_PENDING, this,
                            OP_TYPE_BACKUP_WAIT));
                }
            }

            void unregisterTask() {
                synchronized (mCurrentOpLock) {
                    mCurrentOperations.remove(mCurrentOpToken);
                }
            }

            @Override
            public void run() {
                FileOutputStream out = new FileOutputStream(mOutput.getFileDescriptor());
                mEngine = new FullBackupEngine(out, mPreflight, mTarget, false, this, mQuota, mCurrentOpToken);
                try {
                    try {
                        if (!mIsCancelled) {
                            mPreflightResult = mEngine.preflightCheck();
                        }
                    } finally {
                        mPreflightLatch.countDown();
                    }
                    // If there is no error on preflight, continue backup.
                    if (mPreflightResult == BackupTransport.TRANSPORT_OK) {
                        if (!mIsCancelled) {
                            mBackupResult = mEngine.backupOnePackage();
                        }
                    }
                } catch (Exception e) {
                    Slog.e(TAG, "Exception during full package backup of " + mTarget.packageName);
                } finally {
                    unregisterTask();
                    mBackupLatch.countDown();
                    try {
                        mOutput.close();
                    } catch (IOException e) {
                        Slog.w(TAG, "Error closing transport pipe in runner");
                    }
                }
            }

            public void sendQuotaExceeded(final long backupDataBytes, final long quotaBytes) {
                mEngine.sendQuotaExceeded(backupDataBytes, quotaBytes);
            }

            // If preflight succeeded, returns positive number - preflight size,
            // otherwise return negative error code.
            long getPreflightResultBlocking() {
                try {
                    mPreflightLatch.await(TIMEOUT_FULL_BACKUP_INTERVAL, TimeUnit.MILLISECONDS);
                    if (mIsCancelled) {
                        return BackupManager.ERROR_BACKUP_CANCELLED;
                    }
                    if (mPreflightResult == BackupTransport.TRANSPORT_OK) {
                        return mPreflight.getExpectedSizeOrErrorCode();
                    } else {
                        return mPreflightResult;
                    }
                } catch (InterruptedException e) {
                    return BackupTransport.AGENT_ERROR;
                }
            }

            int getBackupResultBlocking() {
                try {
                    mBackupLatch.await(TIMEOUT_FULL_BACKUP_INTERVAL, TimeUnit.MILLISECONDS);
                    if (mIsCancelled) {
                        return BackupManager.ERROR_BACKUP_CANCELLED;
                    }
                    return mBackupResult;
                } catch (InterruptedException e) {
                    return BackupTransport.AGENT_ERROR;
                }
            }


            // BackupRestoreTask interface: specifically, timeout detection

            @Override
            public void execute() { /* intentionally empty */ }

            @Override
            public void operationComplete(long result) { /* intentionally empty */ }

            @Override
            public void handleCancel(boolean cancelAll) {
                if (DEBUG) {
                    Slog.w(TAG, "Full backup cancel of " + mTarget.packageName);
                }

                mMonitor = monitorEvent(mMonitor,
                        BackupManagerMonitor.LOG_EVENT_ID_FULL_BACKUP_CANCEL,
                        mCurrentPackage, BackupManagerMonitor.LOG_EVENT_CATEGORY_AGENT, null);
                mIsCancelled = true;
                // Cancel tasks spun off by this task.
                BackupManagerService.this.handleCancel(mEphemeralToken, cancelAll);
                tearDownAgentAndKill(mTarget.applicationInfo);
                // Free up everyone waiting on this task and its children.
                mPreflightLatch.countDown();
                mBackupLatch.countDown();
                // We are done with this operation.
                removeOperation(mCurrentOpToken);
            }
        }
    }

    // ----- Full-data backup scheduling -----

    /**
     * Schedule a job to tell us when it's a good time to run a full backup
     */
    void scheduleNextFullBackupJob(long transportMinLatency) {
        synchronized (mQueueLock) {
            if (mFullBackupQueue.size() > 0) {
                // schedule the next job at the point in the future when the least-recently
                // backed up app comes due for backup again; or immediately if it's already
                // due.
                final long upcomingLastBackup = mFullBackupQueue.get(0).lastBackup;
                final long timeSinceLast = System.currentTimeMillis() - upcomingLastBackup;
                final long appLatency = (timeSinceLast < MIN_FULL_BACKUP_INTERVAL)
                        ? (MIN_FULL_BACKUP_INTERVAL - timeSinceLast) : 0;
                final long latency = Math.max(transportMinLatency, appLatency);
                Runnable r = new Runnable() {
                    @Override public void run() {
                        FullBackupJob.schedule(mContext, latency);
                    }
                };
                mBackupHandler.postDelayed(r, 2500);
            } else {
                if (DEBUG_SCHEDULING) {
                    Slog.i(TAG, "Full backup queue empty; not scheduling");
                }
            }
        }
    }

    /**
     * Remove a package from the full-data queue.
     */
    void dequeueFullBackupLocked(String packageName) {
        final int N = mFullBackupQueue.size();
        for (int i = N-1; i >= 0; i--) {
            final FullBackupEntry e = mFullBackupQueue.get(i);
            if (packageName.equals(e.packageName)) {
                mFullBackupQueue.remove(i);
            }
        }
    }

    /**
     * Enqueue full backup for the given app, with a note about when it last ran.
     */
    void enqueueFullBackup(String packageName, long lastBackedUp) {
        FullBackupEntry newEntry = new FullBackupEntry(packageName, lastBackedUp);
        synchronized (mQueueLock) {
            // First, sanity check that we aren't adding a duplicate.  Slow but
            // straightforward; we'll have at most on the order of a few hundred
            // items in this list.
            dequeueFullBackupLocked(packageName);

            // This is also slow but easy for modest numbers of apps: work backwards
            // from the end of the queue until we find an item whose last backup
            // time was before this one, then insert this new entry after it.  If we're
            // adding something new we don't bother scanning, and just prepend.
            int which = -1;
            if (lastBackedUp > 0) {
                for (which = mFullBackupQueue.size() - 1; which >= 0; which--) {
                    final FullBackupEntry entry = mFullBackupQueue.get(which);
                    if (entry.lastBackup <= lastBackedUp) {
                        mFullBackupQueue.add(which + 1, newEntry);
                        break;
                    }
                }
            }
            if (which < 0) {
                // this one is earlier than any existing one, so prepend
                mFullBackupQueue.add(0, newEntry);
            }
        }
        writeFullBackupScheduleAsync();
    }

    private boolean fullBackupAllowable(IBackupTransport transport) {
        if (transport == null) {
            Slog.w(TAG, "Transport not present; full data backup not performed");
            return false;
        }

        // Don't proceed unless we have already established package metadata
        // for the current dataset via a key/value backup pass.
        try {
            File stateDir = new File(mBaseStateDir, transport.transportDirName());
            File pmState = new File(stateDir, PACKAGE_MANAGER_SENTINEL);
            if (pmState.length() <= 0) {
                if (DEBUG) {
                    Slog.i(TAG, "Full backup requested but dataset not yet initialized");
                }
                return false;
            }
        } catch (Exception e) {
            Slog.w(TAG, "Unable to get transport name: " + e.getMessage());
            return false;
        }

        return true;
    }

    /**
     * Conditions are right for a full backup operation, so run one.  The model we use is
     * to perform one app backup per scheduled job execution, and to reschedule the job
     * with zero latency as long as conditions remain right and we still have work to do.
     *
     * <p>This is the "start a full backup operation" entry point called by the scheduled job.
     *
     * @return Whether ongoing work will continue.  The return value here will be passed
     *         along as the return value to the scheduled job's onStartJob() callback.
     */
    @Override
    public boolean beginFullBackup(FullBackupJob scheduledJob) {
        long now = System.currentTimeMillis();
        FullBackupEntry entry = null;
        long latency = MIN_FULL_BACKUP_INTERVAL;

        if (!mEnabled || !mProvisioned) {
            // Backups are globally disabled, so don't proceed.  We also don't reschedule
            // the job driving automatic backups; that job will be scheduled again when
            // the user enables backup.
            if (MORE_DEBUG) {
                Slog.i(TAG, "beginFullBackup but e=" + mEnabled
                        + " p=" + mProvisioned + "; ignoring");
            }
            return false;
        }

        // Don't run the backup if we're in battery saver mode, but reschedule
        // to try again in the not-so-distant future.
        final PowerSaveState result =
                mPowerManager.getPowerSaveState(ServiceType.FULL_BACKUP);
        if (result.batterySaverEnabled) {
            if (DEBUG) Slog.i(TAG, "Deferring scheduled full backups in battery saver mode");
            FullBackupJob.schedule(mContext, KeyValueBackupJob.BATCH_INTERVAL);
            return false;
        }

        if (DEBUG_SCHEDULING) {
            Slog.i(TAG, "Beginning scheduled full backup operation");
        }

        // Great; we're able to run full backup jobs now.  See if we have any work to do.
        synchronized (mQueueLock) {
            if (mRunningFullBackupTask != null) {
                Slog.e(TAG, "Backup triggered but one already/still running!");
                return false;
            }

            // At this point we think that we have work to do, but possibly not right now.
            // Any exit without actually running backups will also require that we
            // reschedule the job.
            boolean runBackup = true;
            boolean headBusy;

            do {
                // Recheck each time, because culling due to ineligibility may
                // have emptied the queue.
                if (mFullBackupQueue.size() == 0) {
                    // no work to do so just bow out
                    if (DEBUG) {
                        Slog.i(TAG, "Backup queue empty; doing nothing");
                    }
                    runBackup = false;
                    break;
                }

                headBusy = false;

                if (!fullBackupAllowable(mTransportManager.getCurrentTransportBinder())) {
                    if (MORE_DEBUG) {
                        Slog.i(TAG, "Preconditions not met; not running full backup");
                    }
                    runBackup = false;
                    // Typically this means we haven't run a key/value backup yet.  Back off
                    // full-backup operations by the key/value job's run interval so that
                    // next time we run, we are likely to be able to make progress.
                    latency = KeyValueBackupJob.BATCH_INTERVAL;
                }

                if (runBackup) {
                    entry = mFullBackupQueue.get(0);
                    long timeSinceRun = now - entry.lastBackup;
                    runBackup = (timeSinceRun >= MIN_FULL_BACKUP_INTERVAL);
                    if (!runBackup) {
                        // It's too early to back up the next thing in the queue, so bow out
                        if (MORE_DEBUG) {
                            Slog.i(TAG, "Device ready but too early to back up next app");
                        }
                        // Wait until the next app in the queue falls due for a full data backup
                        latency = MIN_FULL_BACKUP_INTERVAL - timeSinceRun;
                        break;  // we know we aren't doing work yet, so bail.
                    }

                    try {
                        PackageInfo appInfo = mPackageManager.getPackageInfo(entry.packageName, 0);
                        if (!appGetsFullBackup(appInfo)) {
                            // The head app isn't supposed to get full-data backups [any more];
                            // so we cull it and force a loop around to consider the new head
                            // app.
                            if (MORE_DEBUG) {
                                Slog.i(TAG, "Culling package " + entry.packageName
                                        + " in full-backup queue but not eligible");
                            }
                            mFullBackupQueue.remove(0);
                            headBusy = true; // force the while() condition
                            continue;
                        }

                        final int privFlags = appInfo.applicationInfo.privateFlags;
                        headBusy = (privFlags & PRIVATE_FLAG_BACKUP_IN_FOREGROUND) == 0
                                && mActivityManager.isAppForeground(appInfo.applicationInfo.uid);

                        if (headBusy) {
                            final long nextEligible = System.currentTimeMillis()
                                    + BUSY_BACKOFF_MIN_MILLIS
                                    + mTokenGenerator.nextInt(BUSY_BACKOFF_FUZZ);
                            if (DEBUG_SCHEDULING) {
                                SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
                                Slog.i(TAG, "Full backup time but " + entry.packageName
                                        + " is busy; deferring to "
                                        + sdf.format(new Date(nextEligible)));
                            }
                            // This relocates the app's entry from the head of the queue to
                            // its order-appropriate position further down, so upon looping
                            // a new candidate will be considered at the head.
                            enqueueFullBackup(entry.packageName,
                                    nextEligible - MIN_FULL_BACKUP_INTERVAL);
                        }
                    } catch (NameNotFoundException nnf) {
                        // So, we think we want to back this up, but it turns out the package
                        // in question is no longer installed.  We want to drop it from the
                        // queue entirely and move on, but if there's nothing else in the queue
                        // we should bail entirely.  headBusy cannot have been set to true yet.
                        runBackup = (mFullBackupQueue.size() > 1);
                    } catch (RemoteException e) {
                        // Cannot happen; the Activity Manager is in the same process
                    }
                }
            } while (headBusy);

            if (!runBackup) {
                if (DEBUG_SCHEDULING) {
                    Slog.i(TAG, "Nothing pending full backup; rescheduling +" + latency);
                }
                final long deferTime = latency;     // pin for the closure
                mBackupHandler.post(new Runnable() {
                    @Override public void run() {
                        FullBackupJob.schedule(mContext, deferTime);
                    }
                });
                return false;
            }

            // Okay, the top thing is ready for backup now.  Do it.
            mFullBackupQueue.remove(0);
            CountDownLatch latch = new CountDownLatch(1);
            String[] pkg = new String[] {entry.packageName};
            mRunningFullBackupTask = new PerformFullTransportBackupTask(null, pkg, true,
                    scheduledJob, latch, null, null, false /* userInitiated */);
            // Acquiring wakelock for PerformFullTransportBackupTask before its start.
            mWakelock.acquire();
            (new Thread(mRunningFullBackupTask)).start();
        }

        return true;
    }

    // The job scheduler says our constraints don't hold any more,
    // so tear down any ongoing backup task right away.
    @Override
    public void endFullBackup() {
        // offload the mRunningFullBackupTask.handleCancel() call to another thread,
        // as we might have to wait for mCancelLock
        Runnable endFullBackupRunnable = new Runnable() {
            @Override
            public void run() {
                PerformFullTransportBackupTask pftbt = null;
                synchronized (mQueueLock) {
                    if (mRunningFullBackupTask != null) {
                        pftbt = mRunningFullBackupTask;
                    }
                }
                if (pftbt != null) {
                    if (DEBUG_SCHEDULING) {
                        Slog.i(TAG, "Telling running backup to stop");
                    }
                    pftbt.handleCancel(true);
                }
            }
        };
        new Thread(endFullBackupRunnable, "end-full-backup").start();
    }

    // ----- Restore infrastructure -----

    abstract class RestoreEngine {
        static final String TAG = "RestoreEngine";

        public static final int SUCCESS = 0;
        public static final int TARGET_FAILURE = -2;
        public static final int TRANSPORT_FAILURE = -3;

        private AtomicBoolean mRunning = new AtomicBoolean(false);
        private AtomicInteger mResult = new AtomicInteger(SUCCESS);

        public boolean isRunning() {
            return mRunning.get();
        }

        public void setRunning(boolean stillRunning) {
            synchronized (mRunning) {
                mRunning.set(stillRunning);
                mRunning.notifyAll();
            }
        }

        public int waitForResult() {
            synchronized (mRunning) {
                while (isRunning()) {
                    try {
                        mRunning.wait();
                    } catch (InterruptedException e) {}
                }
            }
            return getResult();
        }

        public int getResult() {
            return mResult.get();
        }

        public void setResult(int result) {
            mResult.set(result);
        }

        // TODO: abstract restore state and APIs
    }

    // ----- Full restore from a file/socket -----

    enum RestorePolicy {
        IGNORE,
        ACCEPT,
        ACCEPT_IF_APK
    }

    // Full restore engine, used by both adb restore and transport-based full restore
    class FullRestoreEngine extends RestoreEngine {
        // Task in charge of monitoring timeouts
        BackupRestoreTask mMonitorTask;

        // Dedicated observer, if any
        IFullBackupRestoreObserver mObserver;

        IBackupManagerMonitor mMonitor;

        // Where we're delivering the file data as we go
        IBackupAgent mAgent;

        // Are we permitted to only deliver a specific package's metadata?
        PackageInfo mOnlyPackage;

        boolean mAllowApks;
        boolean mAllowObbs;

        // Which package are we currently handling data for?
        String mAgentPackage;

        // Info for working with the target app process
        ApplicationInfo mTargetApp;

        // Machinery for restoring OBBs
        FullBackupObbConnection mObbConnection = null;

        // possible handling states for a given package in the restore dataset
        final HashMap<String, RestorePolicy> mPackagePolicies
                = new HashMap<String, RestorePolicy>();

        // installer package names for each encountered app, derived from the manifests
        final HashMap<String, String> mPackageInstallers = new HashMap<String, String>();

        // Signatures for a given package found in its manifest file
        final HashMap<String, Signature[]> mManifestSignatures
                = new HashMap<String, Signature[]>();

        // Packages we've already wiped data on when restoring their first file
        final HashSet<String> mClearedPackages = new HashSet<String>();

        // How much data have we moved?
        long mBytes;

        // Working buffer
        byte[] mBuffer;

        // Pipes for moving data
        ParcelFileDescriptor[] mPipes = null;

        // Widget blob to be restored out-of-band
        byte[] mWidgetData = null;

        private final int mEphemeralOpToken;

        // Runner that can be placed in a separate thread to do in-process
        // invocations of the full restore API asynchronously. Used by adb restore.
        class RestoreFileRunnable implements Runnable {
            IBackupAgent mAgent;
            FileMetadata mInfo;
            ParcelFileDescriptor mSocket;
            int mToken;

            RestoreFileRunnable(IBackupAgent agent, FileMetadata info,
                    ParcelFileDescriptor socket, int token) throws IOException {
                mAgent = agent;
                mInfo = info;
                mToken = token;

                // This class is used strictly for process-local binder invocations.  The
                // semantics of ParcelFileDescriptor differ in this case; in particular, we
                // do not automatically get a 'dup'ed descriptor that we can can continue
                // to use asynchronously from the caller.  So, we make sure to dup it ourselves
                // before proceeding to do the restore.
                mSocket = ParcelFileDescriptor.dup(socket.getFileDescriptor());
            }

            @Override
            public void run() {
                try {
                    mAgent.doRestoreFile(mSocket, mInfo.size, mInfo.type,
                            mInfo.domain, mInfo.path, mInfo.mode, mInfo.mtime,
                            mToken, mBackupManagerBinder);
                } catch (RemoteException e) {
                    // never happens; this is used strictly for local binder calls
                }
            }
        }

        public FullRestoreEngine(BackupRestoreTask monitorTask, IFullBackupRestoreObserver observer,
                IBackupManagerMonitor monitor, PackageInfo onlyPackage, boolean allowApks,
                boolean allowObbs, int ephemeralOpToken) {
            mEphemeralOpToken = ephemeralOpToken;
            mMonitorTask = monitorTask;
            mObserver = observer;
            mMonitor = monitor;
            mOnlyPackage = onlyPackage;
            mAllowApks = allowApks;
            mAllowObbs = allowObbs;
            mBuffer = new byte[32 * 1024];
            mBytes = 0;
        }

        public IBackupAgent getAgent() {
            return mAgent;
        }

        public byte[] getWidgetData() {
            return mWidgetData;
        }

        public boolean restoreOneFile(InputStream instream, boolean mustKillAgent) {
            if (!isRunning()) {
                Slog.w(TAG, "Restore engine used after halting");
                return false;
            }

            FileMetadata info;
            try {
                if (MORE_DEBUG) {
                    Slog.v(TAG, "Reading tar header for restoring file");
                }
                info = readTarHeaders(instream);
                if (info != null) {
                    if (MORE_DEBUG) {
                        dumpFileMetadata(info);
                    }

                    final String pkg = info.packageName;
                    if (!pkg.equals(mAgentPackage)) {
                        // In the single-package case, it's a semantic error to expect
                        // one app's data but see a different app's on the wire
                        if (mOnlyPackage != null) {
                            if (!pkg.equals(mOnlyPackage.packageName)) {
                                Slog.w(TAG, "Expected data for " + mOnlyPackage
                                        + " but saw " + pkg);
                                setResult(RestoreEngine.TRANSPORT_FAILURE);
                                setRunning(false);
                                return false;
                            }
                        }

                        // okay, change in package; set up our various
                        // bookkeeping if we haven't seen it yet
                        if (!mPackagePolicies.containsKey(pkg)) {
                            mPackagePolicies.put(pkg, RestorePolicy.IGNORE);
                        }

                        // Clean up the previous agent relationship if necessary,
                        // and let the observer know we're considering a new app.
                        if (mAgent != null) {
                            if (DEBUG) Slog.d(TAG, "Saw new package; finalizing old one");
                            // Now we're really done
                            tearDownPipes();
                            tearDownAgent(mTargetApp);
                            mTargetApp = null;
                            mAgentPackage = null;
                        }
                    }

                    if (info.path.equals(BACKUP_MANIFEST_FILENAME)) {
                        mPackagePolicies.put(pkg, readAppManifest(info, instream));
                        mPackageInstallers.put(pkg, info.installerPackageName);
                        // We've read only the manifest content itself at this point,
                        // so consume the footer before looping around to the next
                        // input file
                        skipTarPadding(info.size, instream);
                        sendOnRestorePackage(pkg);
                    } else if (info.path.equals(BACKUP_METADATA_FILENAME)) {
                        // Metadata blobs!
                        readMetadata(info, instream);
                        skipTarPadding(info.size, instream);
                    } else {
                        // Non-manifest, so it's actual file data.  Is this a package
                        // we're ignoring?
                        boolean okay = true;
                        RestorePolicy policy = mPackagePolicies.get(pkg);
                        switch (policy) {
                            case IGNORE:
                                okay = false;
                                break;

                            case ACCEPT_IF_APK:
                                // If we're in accept-if-apk state, then the first file we
                                // see MUST be the apk.
                                if (info.domain.equals(FullBackup.APK_TREE_TOKEN)) {
                                    if (DEBUG) Slog.d(TAG, "APK file; installing");
                                    // Try to install the app.
                                    String installerName = mPackageInstallers.get(pkg);
                                    okay = installApk(info, installerName, instream);
                                    // good to go; promote to ACCEPT
                                    mPackagePolicies.put(pkg, (okay)
                                            ? RestorePolicy.ACCEPT
                                                    : RestorePolicy.IGNORE);
                                    // At this point we've consumed this file entry
                                    // ourselves, so just strip the tar footer and
                                    // go on to the next file in the input stream
                                    skipTarPadding(info.size, instream);
                                    return true;
                                } else {
                                    // File data before (or without) the apk.  We can't
                                    // handle it coherently in this case so ignore it.
                                    mPackagePolicies.put(pkg, RestorePolicy.IGNORE);
                                    okay = false;
                                }
                                break;

                            case ACCEPT:
                                if (info.domain.equals(FullBackup.APK_TREE_TOKEN)) {
                                    if (DEBUG) Slog.d(TAG, "apk present but ACCEPT");
                                    // we can take the data without the apk, so we
                                    // *want* to do so.  skip the apk by declaring this
                                    // one file not-okay without changing the restore
                                    // policy for the package.
                                    okay = false;
                                }
                                break;

                            default:
                                // Something has gone dreadfully wrong when determining
                                // the restore policy from the manifest.  Ignore the
                                // rest of this package's data.
                                Slog.e(TAG, "Invalid policy from manifest");
                                okay = false;
                                mPackagePolicies.put(pkg, RestorePolicy.IGNORE);
                                break;
                        }

                        // Is it a *file* we need to drop?
                        if (!isRestorableFile(info)) {
                            okay = false;
                        }

                        // If the policy is satisfied, go ahead and set up to pipe the
                        // data to the agent.
                        if (MORE_DEBUG && okay && mAgent != null) {
                            Slog.i(TAG, "Reusing existing agent instance");
                        }
                        if (okay && mAgent == null) {
                            if (MORE_DEBUG) Slog.d(TAG, "Need to launch agent for " + pkg);

                            try {
                                mTargetApp = mPackageManager.getApplicationInfo(pkg, 0);

                                // If we haven't sent any data to this app yet, we probably
                                // need to clear it first.  Check that.
                                if (!mClearedPackages.contains(pkg)) {
                                    // apps with their own backup agents are
                                    // responsible for coherently managing a full
                                    // restore.
                                    if (mTargetApp.backupAgentName == null) {
                                        if (DEBUG) Slog.d(TAG, "Clearing app data preparatory to full restore");
                                        clearApplicationDataSynchronous(pkg);
                                    } else {
                                        if (MORE_DEBUG) Slog.d(TAG, "backup agent ("
                                                + mTargetApp.backupAgentName + ") => no clear");
                                    }
                                    mClearedPackages.add(pkg);
                                } else {
                                    if (MORE_DEBUG) {
                                        Slog.d(TAG, "We've initialized this app already; no clear required");
                                    }
                                }

                                // All set; now set up the IPC and launch the agent
                                setUpPipes();
                                mAgent = bindToAgentSynchronous(mTargetApp,
                                        ApplicationThreadConstants.BACKUP_MODE_RESTORE_FULL);
                                mAgentPackage = pkg;
                            } catch (IOException e) {
                                // fall through to error handling
                            } catch (NameNotFoundException e) {
                                // fall through to error handling
                            }

                            if (mAgent == null) {
                                Slog.e(TAG, "Unable to create agent for " + pkg);
                                okay = false;
                                tearDownPipes();
                                mPackagePolicies.put(pkg, RestorePolicy.IGNORE);
                            }
                        }

                        // Sanity check: make sure we never give data to the wrong app.  This
                        // should never happen but a little paranoia here won't go amiss.
                        if (okay && !pkg.equals(mAgentPackage)) {
                            Slog.e(TAG, "Restoring data for " + pkg
                                    + " but agent is for " + mAgentPackage);
                            okay = false;
                        }

                        // At this point we have an agent ready to handle the full
                        // restore data as well as a pipe for sending data to
                        // that agent.  Tell the agent to start reading from the
                        // pipe.
                        if (okay) {
                            boolean agentSuccess = true;
                            long toCopy = info.size;
                            try {
                                prepareOperationTimeout(mEphemeralOpToken,
                                        TIMEOUT_FULL_BACKUP_INTERVAL, mMonitorTask,
                                        OP_TYPE_RESTORE_WAIT);

                                if (info.domain.equals(FullBackup.OBB_TREE_TOKEN)) {
                                    if (DEBUG) Slog.d(TAG, "Restoring OBB file for " + pkg
                                            + " : " + info.path);
                                    mObbConnection.restoreObbFile(pkg, mPipes[0],
                                            info.size, info.type, info.path, info.mode,
                                            info.mtime, mEphemeralOpToken, mBackupManagerBinder);
                                } else {
                                    if (MORE_DEBUG) Slog.d(TAG, "Invoking agent to restore file "
                                            + info.path);
                                    // fire up the app's agent listening on the socket.  If
                                    // the agent is running in the system process we can't
                                    // just invoke it asynchronously, so we provide a thread
                                    // for it here.
                                    if (mTargetApp.processName.equals("system")) {
                                        Slog.d(TAG, "system process agent - spinning a thread");
                                        RestoreFileRunnable runner = new RestoreFileRunnable(
                                                mAgent, info, mPipes[0], mEphemeralOpToken);
                                        new Thread(runner, "restore-sys-runner").start();
                                    } else {
                                        mAgent.doRestoreFile(mPipes[0], info.size, info.type,
                                                info.domain, info.path, info.mode, info.mtime,
                                                mEphemeralOpToken, mBackupManagerBinder);
                                    }
                                }
                            } catch (IOException e) {
                                // couldn't dup the socket for a process-local restore
                                Slog.d(TAG, "Couldn't establish restore");
                                agentSuccess = false;
                                okay = false;
                            } catch (RemoteException e) {
                                // whoops, remote entity went away.  We'll eat the content
                                // ourselves, then, and not copy it over.
                                Slog.e(TAG, "Agent crashed during full restore");
                                agentSuccess = false;
                                okay = false;
                            }

                            // Copy over the data if the agent is still good
                            if (okay) {
                                if (MORE_DEBUG) {
                                    Slog.v(TAG, "  copying to restore agent: "
                                            + toCopy + " bytes");
                                }
                                boolean pipeOkay = true;
                                FileOutputStream pipe = new FileOutputStream(
                                        mPipes[1].getFileDescriptor());
                                while (toCopy > 0) {
                                    int toRead = (toCopy > mBuffer.length)
                                            ? mBuffer.length : (int)toCopy;
                                    int nRead = instream.read(mBuffer, 0, toRead);
                                    if (nRead >= 0) mBytes += nRead;
                                    if (nRead <= 0) break;
                                    toCopy -= nRead;

                                    // send it to the output pipe as long as things
                                    // are still good
                                    if (pipeOkay) {
                                        try {
                                            pipe.write(mBuffer, 0, nRead);
                                        } catch (IOException e) {
                                            Slog.e(TAG, "Failed to write to restore pipe: "
                                                    + e.getMessage());
                                            pipeOkay = false;
                                        }
                                    }
                                }

                                // done sending that file!  Now we just need to consume
                                // the delta from info.size to the end of block.
                                skipTarPadding(info.size, instream);

                                // and now that we've sent it all, wait for the remote
                                // side to acknowledge receipt
                                agentSuccess = waitUntilOperationComplete(mEphemeralOpToken);
                            }

                            // okay, if the remote end failed at any point, deal with
                            // it by ignoring the rest of the restore on it
                            if (!agentSuccess) {
                                Slog.w(TAG, "Agent failure; ending restore");
                                mBackupHandler.removeMessages(MSG_RESTORE_OPERATION_TIMEOUT);
                                tearDownPipes();
                                tearDownAgent(mTargetApp);
                                mAgent = null;
                                mPackagePolicies.put(pkg, RestorePolicy.IGNORE);

                                // If this was a single-package restore, we halt immediately
                                // with an agent error under these circumstances
                                if (mOnlyPackage != null) {
                                    setResult(RestoreEngine.TARGET_FAILURE);
                                    setRunning(false);
                                    return false;
                                }
                            }
                        }

                        // Problems setting up the agent communication, an explicitly
                        // dropped file, or an already-ignored package: skip to the
                        // next stream entry by reading and discarding this file.
                        if (!okay) {
                            if (MORE_DEBUG) Slog.d(TAG, "[discarding file content]");
                            long bytesToConsume = (info.size + 511) & ~511;
                            while (bytesToConsume > 0) {
                                int toRead = (bytesToConsume > mBuffer.length)
                                        ? mBuffer.length : (int)bytesToConsume;
                                long nRead = instream.read(mBuffer, 0, toRead);
                                if (nRead >= 0) mBytes += nRead;
                                if (nRead <= 0) break;
                                bytesToConsume -= nRead;
                            }
                        }
                    }
                }
            } catch (IOException e) {
                if (DEBUG) Slog.w(TAG, "io exception on restore socket read: " + e.getMessage());
                setResult(RestoreEngine.TRANSPORT_FAILURE);
                info = null;
            }

            // If we got here we're either running smoothly or we've finished
            if (info == null) {
                if (MORE_DEBUG) {
                    Slog.i(TAG, "No [more] data for this package; tearing down");
                }
                tearDownPipes();
                setRunning(false);
                if (mustKillAgent) {
                    tearDownAgent(mTargetApp);
                }
            }
            return (info != null);
        }

        void setUpPipes() throws IOException {
            mPipes = ParcelFileDescriptor.createPipe();
        }

        void tearDownPipes() {
            // Teardown might arise from the inline restore processing or from the asynchronous
            // timeout mechanism, and these might race.  Make sure we don't try to close and
            // null out the pipes twice.
            synchronized (this) {
                if (mPipes != null) {
                    try {
                        mPipes[0].close();
                        mPipes[0] = null;
                        mPipes[1].close();
                        mPipes[1] = null;
                    } catch (IOException e) {
                        Slog.w(TAG, "Couldn't close agent pipes", e);
                    }
                    mPipes = null;
                }
            }
        }

        void tearDownAgent(ApplicationInfo app) {
            if (mAgent != null) {
                tearDownAgentAndKill(app);
                mAgent = null;
            }
        }

        void handleTimeout() {
            tearDownPipes();
            setResult(RestoreEngine.TARGET_FAILURE);
            setRunning(false);
        }

        class RestoreInstallObserver extends PackageInstallObserver {
            final AtomicBoolean mDone = new AtomicBoolean();
            String mPackageName;
            int mResult;

            public void reset() {
                synchronized (mDone) {
                    mDone.set(false);
                }
            }

            public void waitForCompletion() {
                synchronized (mDone) {
                    while (mDone.get() == false) {
                        try {
                            mDone.wait();
                        } catch (InterruptedException e) { }
                    }
                }
            }

            int getResult() {
                return mResult;
            }

            @Override
            public void onPackageInstalled(String packageName, int returnCode,
                    String msg, Bundle extras) {
                synchronized (mDone) {
                    mResult = returnCode;
                    mPackageName = packageName;
                    mDone.set(true);
                    mDone.notifyAll();
                }
            }
        }

        class RestoreDeleteObserver extends IPackageDeleteObserver.Stub {
            final AtomicBoolean mDone = new AtomicBoolean();
            int mResult;

            public void reset() {
                synchronized (mDone) {
                    mDone.set(false);
                }
            }

            public void waitForCompletion() {
                synchronized (mDone) {
                    while (mDone.get() == false) {
                        try {
                            mDone.wait();
                        } catch (InterruptedException e) { }
                    }
                }
            }

            @Override
            public void packageDeleted(String packageName, int returnCode) throws RemoteException {
                synchronized (mDone) {
                    mResult = returnCode;
                    mDone.set(true);
                    mDone.notifyAll();
                }
            }
        }

        final RestoreInstallObserver mInstallObserver = new RestoreInstallObserver();
        final RestoreDeleteObserver mDeleteObserver = new RestoreDeleteObserver();

        boolean installApk(FileMetadata info, String installerPackage, InputStream instream) {
            boolean okay = true;

            if (DEBUG) Slog.d(TAG, "Installing from backup: " + info.packageName);

            // The file content is an .apk file.  Copy it out to a staging location and
            // attempt to install it.
            File apkFile = new File(mDataDir, info.packageName);
            try {
                FileOutputStream apkStream = new FileOutputStream(apkFile);
                byte[] buffer = new byte[32 * 1024];
                long size = info.size;
                while (size > 0) {
                    long toRead = (buffer.length < size) ? buffer.length : size;
                    int didRead = instream.read(buffer, 0, (int)toRead);
                    if (didRead >= 0) mBytes += didRead;
                    apkStream.write(buffer, 0, didRead);
                    size -= didRead;
                }
                apkStream.close();

                // make sure the installer can read it
                apkFile.setReadable(true, false);

                // Now install it
                Uri packageUri = Uri.fromFile(apkFile);
                mInstallObserver.reset();
                mPackageManager.installPackage(packageUri, mInstallObserver,
                        PackageManager.INSTALL_REPLACE_EXISTING | PackageManager.INSTALL_FROM_ADB,
                        installerPackage);
                mInstallObserver.waitForCompletion();

                if (mInstallObserver.getResult() != PackageManager.INSTALL_SUCCEEDED) {
                    // The only time we continue to accept install of data even if the
                    // apk install failed is if we had already determined that we could
                    // accept the data regardless.
                    if (mPackagePolicies.get(info.packageName) != RestorePolicy.ACCEPT) {
                        okay = false;
                    }
                } else {
                    // Okay, the install succeeded.  Make sure it was the right app.
                    boolean uninstall = false;
                    if (!mInstallObserver.mPackageName.equals(info.packageName)) {
                        Slog.w(TAG, "Restore stream claimed to include apk for "
                                + info.packageName + " but apk was really "
                                + mInstallObserver.mPackageName);
                        // delete the package we just put in place; it might be fraudulent
                        okay = false;
                        uninstall = true;
                    } else {
                        try {
                            PackageInfo pkg = mPackageManager.getPackageInfo(info.packageName,
                                    PackageManager.GET_SIGNATURES);
                            if ((pkg.applicationInfo.flags & ApplicationInfo.FLAG_ALLOW_BACKUP) == 0) {
                                Slog.w(TAG, "Restore stream contains apk of package "
                                        + info.packageName + " but it disallows backup/restore");
                                okay = false;
                            } else {
                                // So far so good -- do the signatures match the manifest?
                                Signature[] sigs = mManifestSignatures.get(info.packageName);
                                if (signaturesMatch(sigs, pkg)) {
                                    // If this is a system-uid app without a declared backup agent,
                                    // don't restore any of the file data.
                                    if ((pkg.applicationInfo.uid < Process.FIRST_APPLICATION_UID)
                                            && (pkg.applicationInfo.backupAgentName == null)) {
                                        Slog.w(TAG, "Installed app " + info.packageName
                                                + " has restricted uid and no agent");
                                        okay = false;
                                    }
                                } else {
                                    Slog.w(TAG, "Installed app " + info.packageName
                                            + " signatures do not match restore manifest");
                                    okay = false;
                                    uninstall = true;
                                }
                            }
                        } catch (NameNotFoundException e) {
                            Slog.w(TAG, "Install of package " + info.packageName
                                    + " succeeded but now not found");
                            okay = false;
                        }
                    }

                    // If we're not okay at this point, we need to delete the package
                    // that we just installed.
                    if (uninstall) {
                        mDeleteObserver.reset();
                        mPackageManager.deletePackage(mInstallObserver.mPackageName,
                                mDeleteObserver, 0);
                        mDeleteObserver.waitForCompletion();
                    }
                }
            } catch (IOException e) {
                Slog.e(TAG, "Unable to transcribe restored apk for install");
                okay = false;
            } finally {
                apkFile.delete();
            }

            return okay;
        }

        // Given an actual file content size, consume the post-content padding mandated
        // by the tar format.
        void skipTarPadding(long size, InputStream instream) throws IOException {
            long partial = (size + 512) % 512;
            if (partial > 0) {
                final int needed = 512 - (int)partial;
                if (MORE_DEBUG) {
                    Slog.i(TAG, "Skipping tar padding: " + needed + " bytes");
                }
                byte[] buffer = new byte[needed];
                if (readExactly(instream, buffer, 0, needed) == needed) {
                    mBytes += needed;
                } else throw new IOException("Unexpected EOF in padding");
            }
        }

        // Read a widget metadata file, returning the restored blob
        void readMetadata(FileMetadata info, InputStream instream) throws IOException {
            // Fail on suspiciously large widget dump files
            if (info.size > 64 * 1024) {
                throw new IOException("Metadata too big; corrupt? size=" + info.size);
            }

            byte[] buffer = new byte[(int) info.size];
            if (readExactly(instream, buffer, 0, (int)info.size) == info.size) {
                mBytes += info.size;
            } else throw new IOException("Unexpected EOF in widget data");

            String[] str = new String[1];
            int offset = extractLine(buffer, 0, str);
            int version = Integer.parseInt(str[0]);
            if (version == BACKUP_MANIFEST_VERSION) {
                offset = extractLine(buffer, offset, str);
                final String pkg = str[0];
                if (info.packageName.equals(pkg)) {
                    // Data checks out -- the rest of the buffer is a concatenation of
                    // binary blobs as described in the comment at writeAppWidgetData()
                    ByteArrayInputStream bin = new ByteArrayInputStream(buffer,
                            offset, buffer.length - offset);
                    DataInputStream in = new DataInputStream(bin);
                    while (bin.available() > 0) {
                        int token = in.readInt();
                        int size = in.readInt();
                        if (size > 64 * 1024) {
                            throw new IOException("Datum "
                                    + Integer.toHexString(token)
                                    + " too big; corrupt? size=" + info.size);
                        }
                        switch (token) {
                            case BACKUP_WIDGET_METADATA_TOKEN:
                            {
                                if (MORE_DEBUG) {
                                    Slog.i(TAG, "Got widget metadata for " + info.packageName);
                                }
                                mWidgetData = new byte[size];
                                in.read(mWidgetData);
                                break;
                            }
                            default:
                            {
                                if (DEBUG) {
                                    Slog.i(TAG, "Ignoring metadata blob "
                                            + Integer.toHexString(token)
                                            + " for " + info.packageName);
                                }
                                in.skipBytes(size);
                                break;
                            }
                        }
                    }
                } else {
                    Slog.w(TAG, "Metadata mismatch: package " + info.packageName
                            + " but widget data for " + pkg);

                    Bundle monitoringExtras = putMonitoringExtra(null,
                            EXTRA_LOG_EVENT_PACKAGE_NAME, info.packageName);
                    monitoringExtras = putMonitoringExtra(monitoringExtras,
                            BackupManagerMonitor.EXTRA_LOG_WIDGET_PACKAGE_NAME, pkg);
                    mMonitor = monitorEvent(mMonitor,
                            BackupManagerMonitor.LOG_EVENT_ID_WIDGET_METADATA_MISMATCH,
                            null,
                            LOG_EVENT_CATEGORY_BACKUP_MANAGER_POLICY,
                            monitoringExtras);
                }
            } else {
                Slog.w(TAG, "Unsupported metadata version " + version);

                Bundle monitoringExtras = putMonitoringExtra(null, EXTRA_LOG_EVENT_PACKAGE_NAME,
                        info.packageName);
                monitoringExtras = putMonitoringExtra(monitoringExtras,
                        EXTRA_LOG_EVENT_PACKAGE_VERSION, version);
                mMonitor = monitorEvent(mMonitor,
                        BackupManagerMonitor.LOG_EVENT_ID_WIDGET_UNKNOWN_VERSION,
                        null,
                        LOG_EVENT_CATEGORY_BACKUP_MANAGER_POLICY,
                        monitoringExtras);
            }
        }

        // Returns a policy constant
        RestorePolicy readAppManifest(FileMetadata info, InputStream instream)
                throws IOException {
            // Fail on suspiciously large manifest files
            if (info.size > 64 * 1024) {
                throw new IOException("Restore manifest too big; corrupt? size=" + info.size);
            }

            byte[] buffer = new byte[(int) info.size];
            if (MORE_DEBUG) {
                Slog.i(TAG, "   readAppManifest() looking for " + info.size + " bytes, "
                        + mBytes + " already consumed");
            }
            if (readExactly(instream, buffer, 0, (int)info.size) == info.size) {
                mBytes += info.size;
            } else throw new IOException("Unexpected EOF in manifest");

            RestorePolicy policy = RestorePolicy.IGNORE;
            String[] str = new String[1];
            int offset = 0;

            try {
                offset = extractLine(buffer, offset, str);
                int version = Integer.parseInt(str[0]);
                if (version == BACKUP_MANIFEST_VERSION) {
                    offset = extractLine(buffer, offset, str);
                    String manifestPackage = str[0];
                    // TODO: handle <original-package>
                    if (manifestPackage.equals(info.packageName)) {
                        offset = extractLine(buffer, offset, str);
                        version = Integer.parseInt(str[0]);  // app version
                        offset = extractLine(buffer, offset, str);
                        // This is the platform version, which we don't use, but we parse it
                        // as a safety against corruption in the manifest.
                        Integer.parseInt(str[0]);
                        offset = extractLine(buffer, offset, str);
                        info.installerPackageName = (str[0].length() > 0) ? str[0] : null;
                        offset = extractLine(buffer, offset, str);
                        boolean hasApk = str[0].equals("1");
                        offset = extractLine(buffer, offset, str);
                        int numSigs = Integer.parseInt(str[0]);
                        if (numSigs > 0) {
                            Signature[] sigs = new Signature[numSigs];
                            for (int i = 0; i < numSigs; i++) {
                                offset = extractLine(buffer, offset, str);
                                sigs[i] = new Signature(str[0]);
                            }
                            mManifestSignatures.put(info.packageName, sigs);

                            // Okay, got the manifest info we need...
                            try {
                                PackageInfo pkgInfo = mPackageManager.getPackageInfo(
                                        info.packageName, PackageManager.GET_SIGNATURES);
                                // Fall through to IGNORE if the app explicitly disallows backup
                                final int flags = pkgInfo.applicationInfo.flags;
                                if ((flags & ApplicationInfo.FLAG_ALLOW_BACKUP) != 0) {
                                    // Restore system-uid-space packages only if they have
                                    // defined a custom backup agent
                                    if ((pkgInfo.applicationInfo.uid >= Process.FIRST_APPLICATION_UID)
                                            || (pkgInfo.applicationInfo.backupAgentName != null)) {
                                        // Verify signatures against any installed version; if they
                                        // don't match, then we fall though and ignore the data.  The
                                        // signatureMatch() method explicitly ignores the signature
                                        // check for packages installed on the system partition, because
                                        // such packages are signed with the platform cert instead of
                                        // the app developer's cert, so they're different on every
                                        // device.
                                        if (signaturesMatch(sigs, pkgInfo)) {
                                            if ((pkgInfo.applicationInfo.flags
                                                    & ApplicationInfo.FLAG_RESTORE_ANY_VERSION) != 0) {
                                                Slog.i(TAG, "Package has restoreAnyVersion; taking data");
                                                mMonitor = monitorEvent(mMonitor,
                                                        LOG_EVENT_ID_RESTORE_ANY_VERSION,
                                                        pkgInfo,
                                                        LOG_EVENT_CATEGORY_BACKUP_MANAGER_POLICY,
                                                        null);
                                                policy = RestorePolicy.ACCEPT;
                                            } else if (pkgInfo.versionCode >= version) {
                                                Slog.i(TAG, "Sig + version match; taking data");
                                                policy = RestorePolicy.ACCEPT;
                                                mMonitor = monitorEvent(mMonitor,
                                                        LOG_EVENT_ID_VERSIONS_MATCH,
                                                        pkgInfo,
                                                        LOG_EVENT_CATEGORY_BACKUP_MANAGER_POLICY,
                                                        null);
                                            } else {
                                                // The data is from a newer version of the app than
                                                // is presently installed.  That means we can only
                                                // use it if the matching apk is also supplied.
                                                if (mAllowApks) {
                                                    Slog.i(TAG, "Data version " + version
                                                            + " is newer than installed version "
                                                            + pkgInfo.versionCode
                                                            + " - requiring apk");
                                                    policy = RestorePolicy.ACCEPT_IF_APK;
                                                } else {
                                                    Slog.i(TAG, "Data requires newer version "
                                                            + version + "; ignoring");
                                                    mMonitor = monitorEvent(mMonitor,
                                                            LOG_EVENT_ID_VERSION_OF_BACKUP_OLDER,
                                                            pkgInfo,
                                                            LOG_EVENT_CATEGORY_BACKUP_MANAGER_POLICY,
                                                            putMonitoringExtra(null,
                                                                    EXTRA_LOG_OLD_VERSION,
                                                                    version));

                                                    policy = RestorePolicy.IGNORE;
                                                }
                                            }
                                        } else {
                                            Slog.w(TAG, "Restore manifest signatures do not match "
                                                    + "installed application for " + info.packageName);
                                            mMonitor = monitorEvent(mMonitor,
                                                    LOG_EVENT_ID_FULL_RESTORE_SIGNATURE_MISMATCH,
                                                    pkgInfo,
                                                    LOG_EVENT_CATEGORY_BACKUP_MANAGER_POLICY,
                                                    null);
                                        }
                                    } else {
                                        Slog.w(TAG, "Package " + info.packageName
                                                + " is system level with no agent");
                                        mMonitor = monitorEvent(mMonitor,
                                                LOG_EVENT_ID_SYSTEM_APP_NO_AGENT,
                                                pkgInfo,
                                                LOG_EVENT_CATEGORY_AGENT,
                                                null);
                                    }
                                } else {
                                    if (DEBUG) Slog.i(TAG, "Restore manifest from "
                                            + info.packageName + " but allowBackup=false");
                                    mMonitor = monitorEvent(mMonitor,
                                            LOG_EVENT_ID_FULL_RESTORE_ALLOW_BACKUP_FALSE,
                                            pkgInfo,
                                            LOG_EVENT_CATEGORY_BACKUP_MANAGER_POLICY,
                                            null);
                                }
                            } catch (NameNotFoundException e) {
                                // Okay, the target app isn't installed.  We can process
                                // the restore properly only if the dataset provides the
                                // apk file and we can successfully install it.
                                if (mAllowApks) {
                                    if (DEBUG) Slog.i(TAG, "Package " + info.packageName
                                            + " not installed; requiring apk in dataset");
                                    policy = RestorePolicy.ACCEPT_IF_APK;
                                } else {
                                    policy = RestorePolicy.IGNORE;
                                }
                                Bundle monitoringExtras = putMonitoringExtra(null,
                                        EXTRA_LOG_EVENT_PACKAGE_NAME, info.packageName);
                                monitoringExtras = putMonitoringExtra(monitoringExtras,
                                        EXTRA_LOG_POLICY_ALLOW_APKS, mAllowApks);
                                mMonitor = monitorEvent(mMonitor,
                                        LOG_EVENT_ID_APK_NOT_INSTALLED,
                                        null,
                                        LOG_EVENT_CATEGORY_BACKUP_MANAGER_POLICY,
                                        monitoringExtras);
                            }

                            if (policy == RestorePolicy.ACCEPT_IF_APK && !hasApk) {
                                Slog.i(TAG, "Cannot restore package " + info.packageName
                                        + " without the matching .apk");
                                mMonitor = monitorEvent(mMonitor,
                                        LOG_EVENT_ID_CANNOT_RESTORE_WITHOUT_APK,
                                        null,
                                        LOG_EVENT_CATEGORY_BACKUP_MANAGER_POLICY,
                                        putMonitoringExtra(null,
                                                EXTRA_LOG_EVENT_PACKAGE_NAME, info.packageName));
                            }
                        } else {
                            Slog.i(TAG, "Missing signature on backed-up package "
                                    + info.packageName);
                            mMonitor = monitorEvent(mMonitor,
                                    LOG_EVENT_ID_MISSING_SIGNATURE,
                                    null,
                                    LOG_EVENT_CATEGORY_BACKUP_MANAGER_POLICY,
                                    putMonitoringExtra(null,
                                            EXTRA_LOG_EVENT_PACKAGE_NAME, info.packageName));
                        }
                    } else {
                        Slog.i(TAG, "Expected package " + info.packageName
                                + " but restore manifest claims " + manifestPackage);
                        Bundle monitoringExtras = putMonitoringExtra(null,
                                EXTRA_LOG_EVENT_PACKAGE_NAME, info.packageName);
                        monitoringExtras = putMonitoringExtra(monitoringExtras,
                                EXTRA_LOG_MANIFEST_PACKAGE_NAME, manifestPackage);
                        mMonitor = monitorEvent(mMonitor,
                                LOG_EVENT_ID_EXPECTED_DIFFERENT_PACKAGE,
                                null,
                                LOG_EVENT_CATEGORY_BACKUP_MANAGER_POLICY,
                                monitoringExtras);
                    }
                } else {
                    Slog.i(TAG, "Unknown restore manifest version " + version
                            + " for package " + info.packageName);
                    Bundle monitoringExtras = putMonitoringExtra(null,
                            EXTRA_LOG_EVENT_PACKAGE_NAME, info.packageName);
                    monitoringExtras = putMonitoringExtra(monitoringExtras,
                            EXTRA_LOG_EVENT_PACKAGE_VERSION, version);
                    mMonitor = monitorEvent(mMonitor,
                            BackupManagerMonitor.LOG_EVENT_ID_UNKNOWN_VERSION,
                            null,
                            LOG_EVENT_CATEGORY_BACKUP_MANAGER_POLICY,
                            monitoringExtras);

                }
            } catch (NumberFormatException e) {
                Slog.w(TAG, "Corrupt restore manifest for package " + info.packageName);
                mMonitor = monitorEvent(mMonitor,
                        BackupManagerMonitor.LOG_EVENT_ID_CORRUPT_MANIFEST,
                        null,
                        LOG_EVENT_CATEGORY_BACKUP_MANAGER_POLICY,
                        putMonitoringExtra(null, EXTRA_LOG_EVENT_PACKAGE_NAME, info.packageName));
            } catch (IllegalArgumentException e) {
                Slog.w(TAG, e.getMessage());
            }

            return policy;
        }

        // Builds a line from a byte buffer starting at 'offset', and returns
        // the index of the next unconsumed data in the buffer.
        int extractLine(byte[] buffer, int offset, String[] outStr) throws IOException {
            final int end = buffer.length;
            if (offset >= end) throw new IOException("Incomplete data");

            int pos;
            for (pos = offset; pos < end; pos++) {
                byte c = buffer[pos];
                // at LF we declare end of line, and return the next char as the
                // starting point for the next time through
                if (c == '\n') {
                    break;
                }
            }
            outStr[0] = new String(buffer, offset, pos - offset);
            pos++;  // may be pointing an extra byte past the end but that's okay
            return pos;
        }

        void dumpFileMetadata(FileMetadata info) {
            if (MORE_DEBUG) {
                StringBuilder b = new StringBuilder(128);

                // mode string
                b.append((info.type == BackupAgent.TYPE_DIRECTORY) ? 'd' : '-');
                b.append(((info.mode & 0400) != 0) ? 'r' : '-');
                b.append(((info.mode & 0200) != 0) ? 'w' : '-');
                b.append(((info.mode & 0100) != 0) ? 'x' : '-');
                b.append(((info.mode & 0040) != 0) ? 'r' : '-');
                b.append(((info.mode & 0020) != 0) ? 'w' : '-');
                b.append(((info.mode & 0010) != 0) ? 'x' : '-');
                b.append(((info.mode & 0004) != 0) ? 'r' : '-');
                b.append(((info.mode & 0002) != 0) ? 'w' : '-');
                b.append(((info.mode & 0001) != 0) ? 'x' : '-');
                b.append(String.format(" %9d ", info.size));

                Date stamp = new Date(info.mtime);
                b.append(new SimpleDateFormat("MMM dd HH:mm:ss ").format(stamp));

                b.append(info.packageName);
                b.append(" :: ");
                b.append(info.domain);
                b.append(" :: ");
                b.append(info.path);

                Slog.i(TAG, b.toString());
            }
        }

        // Consume a tar file header block [sequence] and accumulate the relevant metadata
        FileMetadata readTarHeaders(InputStream instream) throws IOException {
            byte[] block = new byte[512];
            FileMetadata info = null;

            boolean gotHeader = readTarHeader(instream, block);
            if (gotHeader) {
                try {
                    // okay, presume we're okay, and extract the various metadata
                    info = new FileMetadata();
                    info.size = extractRadix(block, TAR_HEADER_OFFSET_FILESIZE,
                            TAR_HEADER_LENGTH_FILESIZE, TAR_HEADER_LONG_RADIX);
                    info.mtime = extractRadix(block, TAR_HEADER_OFFSET_MODTIME,
                            TAR_HEADER_LENGTH_MODTIME, TAR_HEADER_LONG_RADIX);
                    info.mode = extractRadix(block, TAR_HEADER_OFFSET_MODE,
                            TAR_HEADER_LENGTH_MODE, TAR_HEADER_LONG_RADIX);

                    info.path = extractString(block, TAR_HEADER_OFFSET_PATH_PREFIX,
                            TAR_HEADER_LENGTH_PATH_PREFIX);
                    String path = extractString(block, TAR_HEADER_OFFSET_PATH,
                            TAR_HEADER_LENGTH_PATH);
                    if (path.length() > 0) {
                        if (info.path.length() > 0) info.path += '/';
                        info.path += path;
                    }

                    // tar link indicator field: 1 byte at offset 156 in the header.
                    int typeChar = block[TAR_HEADER_OFFSET_TYPE_CHAR];
                    if (typeChar == 'x') {
                        // pax extended header, so we need to read that
                        gotHeader = readPaxExtendedHeader(instream, info);
                        if (gotHeader) {
                            // and after a pax extended header comes another real header -- read
                            // that to find the real file type
                            gotHeader = readTarHeader(instream, block);
                        }
                        if (!gotHeader) throw new IOException("Bad or missing pax header");

                        typeChar = block[TAR_HEADER_OFFSET_TYPE_CHAR];
                    }

                    switch (typeChar) {
                        case '0': info.type = BackupAgent.TYPE_FILE; break;
                        case '5': {
                            info.type = BackupAgent.TYPE_DIRECTORY;
                            if (info.size != 0) {
                                Slog.w(TAG, "Directory entry with nonzero size in header");
                                info.size = 0;
                            }
                            break;
                        }
                        case 0: {
                            // presume EOF
                            if (MORE_DEBUG) Slog.w(TAG, "Saw type=0 in tar header block, info=" + info);
                            return null;
                        }
                        default: {
                            Slog.e(TAG, "Unknown tar entity type: " + typeChar);
                            throw new IOException("Unknown entity type " + typeChar);
                        }
                    }

                    // Parse out the path
                    //
                    // first: apps/shared/unrecognized
                    if (FullBackup.SHARED_PREFIX.regionMatches(0,
                            info.path, 0, FullBackup.SHARED_PREFIX.length())) {
                        // File in shared storage.  !!! TODO: implement this.
                        info.path = info.path.substring(FullBackup.SHARED_PREFIX.length());
                        info.packageName = SHARED_BACKUP_AGENT_PACKAGE;
                        info.domain = FullBackup.SHARED_STORAGE_TOKEN;
                        if (DEBUG) Slog.i(TAG, "File in shared storage: " + info.path);
                    } else if (FullBackup.APPS_PREFIX.regionMatches(0,
                            info.path, 0, FullBackup.APPS_PREFIX.length())) {
                        // App content!  Parse out the package name and domain

                        // strip the apps/ prefix
                        info.path = info.path.substring(FullBackup.APPS_PREFIX.length());

                        // extract the package name
                        int slash = info.path.indexOf('/');
                        if (slash < 0) throw new IOException("Illegal semantic path in " + info.path);
                        info.packageName = info.path.substring(0, slash);
                        info.path = info.path.substring(slash+1);

                        // if it's a manifest or metadata payload we're done, otherwise parse
                        // out the domain into which the file will be restored
                        if (!info.path.equals(BACKUP_MANIFEST_FILENAME)
                                && !info.path.equals(BACKUP_METADATA_FILENAME)) {
                            slash = info.path.indexOf('/');
                            if (slash < 0) {
                                throw new IOException("Illegal semantic path in non-manifest "
                                        + info.path);
                            }
                            info.domain = info.path.substring(0, slash);
                            info.path = info.path.substring(slash + 1);
                        }
                    }
                } catch (IOException e) {
                    if (DEBUG) {
                        Slog.e(TAG, "Parse error in header: " + e.getMessage());
                        if (MORE_DEBUG) {
                            HEXLOG(block);
                        }
                    }
                    throw e;
                }
            }
            return info;
        }

        private boolean isRestorableFile(FileMetadata info) {
            if (FullBackup.CACHE_TREE_TOKEN.equals(info.domain)) {
                if (MORE_DEBUG) {
                    Slog.i(TAG, "Dropping cache file path " + info.path);
                }
                return false;
            }

            if (FullBackup.ROOT_TREE_TOKEN.equals(info.domain)) {
                // It's possible this is "no-backup" dir contents in an archive stream
                // produced on a device running a version of the OS that predates that
                // API.  Respect the no-backup intention and don't let the data get to
                // the app.
                if (info.path.startsWith("no_backup/")) {
                    if (MORE_DEBUG) {
                        Slog.i(TAG, "Dropping no_backup file path " + info.path);
                    }
                    return false;
                }
            }

            // The path needs to be canonical
            if (info.path.contains("..") || info.path.contains("//")) {
                if (MORE_DEBUG) {
                    Slog.w(TAG, "Dropping invalid path " + info.path);
                }
                return false;
            }

            // Otherwise we think this file is good to go
            return true;
        }

        private void HEXLOG(byte[] block) {
            int offset = 0;
            int todo = block.length;
            StringBuilder buf = new StringBuilder(64);
            while (todo > 0) {
                buf.append(String.format("%04x   ", offset));
                int numThisLine = (todo > 16) ? 16 : todo;
                for (int i = 0; i < numThisLine; i++) {
                    buf.append(String.format("%02x ", block[offset+i]));
                }
                Slog.i("hexdump", buf.toString());
                buf.setLength(0);
                todo -= numThisLine;
                offset += numThisLine;
            }
        }

        // Read exactly the given number of bytes into a buffer at the stated offset.
        // Returns false if EOF is encountered before the requested number of bytes
        // could be read.
        int readExactly(InputStream in, byte[] buffer, int offset, int size)
                throws IOException {
            if (size <= 0) throw new IllegalArgumentException("size must be > 0");
if (MORE_DEBUG) Slog.i(TAG, "  ... readExactly(" + size + ") called");
            int soFar = 0;
            while (soFar < size) {
                int nRead = in.read(buffer, offset + soFar, size - soFar);
                if (nRead <= 0) {
                    if (MORE_DEBUG) Slog.w(TAG, "- wanted exactly " + size + " but got only " + soFar);
                    break;
                }
                soFar += nRead;
if (MORE_DEBUG) Slog.v(TAG, "   + got " + nRead + "; now wanting " + (size - soFar));
            }
            return soFar;
        }

        boolean readTarHeader(InputStream instream, byte[] block) throws IOException {
            final int got = readExactly(instream, block, 0, 512);
            if (got == 0) return false;     // Clean EOF
            if (got < 512) throw new IOException("Unable to read full block header");
            mBytes += 512;
            return true;
        }

        // overwrites 'info' fields based on the pax extended header
        boolean readPaxExtendedHeader(InputStream instream, FileMetadata info)
                throws IOException {
            // We should never see a pax extended header larger than this
            if (info.size > 32*1024) {
                Slog.w(TAG, "Suspiciously large pax header size " + info.size
                        + " - aborting");
                throw new IOException("Sanity failure: pax header size " + info.size);
            }

            // read whole blocks, not just the content size
            int numBlocks = (int)((info.size + 511) >> 9);
            byte[] data = new byte[numBlocks * 512];
            if (readExactly(instream, data, 0, data.length) < data.length) {
                throw new IOException("Unable to read full pax header");
            }
            mBytes += data.length;

            final int contentSize = (int) info.size;
            int offset = 0;
            do {
                // extract the line at 'offset'
                int eol = offset+1;
                while (eol < contentSize && data[eol] != ' ') eol++;
                if (eol >= contentSize) {
                    // error: we just hit EOD looking for the end of the size field
                    throw new IOException("Invalid pax data");
                }
                // eol points to the space between the count and the key
                int linelen = (int) extractRadix(data, offset, eol - offset, 10);
                int key = eol + 1;  // start of key=value
                eol = offset + linelen - 1; // trailing LF
                int value;
                for (value = key+1; data[value] != '=' && value <= eol; value++);
                if (value > eol) {
                    throw new IOException("Invalid pax declaration");
                }

                // pax requires that key/value strings be in UTF-8
                String keyStr = new String(data, key, value-key, "UTF-8");
                // -1 to strip the trailing LF
                String valStr = new String(data, value+1, eol-value-1, "UTF-8");

                if ("path".equals(keyStr)) {
                    info.path = valStr;
                } else if ("size".equals(keyStr)) {
                    info.size = Long.parseLong(valStr);
                } else {
                    if (DEBUG) Slog.i(TAG, "Unhandled pax key: " + key);
                }

                offset += linelen;
            } while (offset < contentSize);

            return true;
        }

        long extractRadix(byte[] data, int offset, int maxChars, int radix)
                throws IOException {
            long value = 0;
            final int end = offset + maxChars;
            for (int i = offset; i < end; i++) {
                final byte b = data[i];
                // Numeric fields in tar can terminate with either NUL or SPC
                if (b == 0 || b == ' ') break;
                if (b < '0' || b > ('0' + radix - 1)) {
                    throw new IOException("Invalid number in header: '" + (char)b
                            + "' for radix " + radix);
                }
                value = radix * value + (b - '0');
            }
            return value;
        }

        String extractString(byte[] data, int offset, int maxChars) throws IOException {
            final int end = offset + maxChars;
            int eos = offset;
            // tar string fields terminate early with a NUL
            while (eos < end && data[eos] != 0) eos++;
            return new String(data, offset, eos-offset, "US-ASCII");
        }

        void sendStartRestore() {
            if (mObserver != null) {
                try {
                    mObserver.onStartRestore();
                } catch (RemoteException e) {
                    Slog.w(TAG, "full restore observer went away: startRestore");
                    mObserver = null;
                }
            }
        }

        void sendOnRestorePackage(String name) {
            if (mObserver != null) {
                try {
                    // TODO: use a more user-friendly name string
                    mObserver.onRestorePackage(name);
                } catch (RemoteException e) {
                    Slog.w(TAG, "full restore observer went away: restorePackage");
                    mObserver = null;
                }
            }
        }

        void sendEndRestore() {
            if (mObserver != null) {
                try {
                    mObserver.onEndRestore();
                } catch (RemoteException e) {
                    Slog.w(TAG, "full restore observer went away: endRestore");
                    mObserver = null;
                }
            }
        }
    }

    // ***** end new engine class ***

    // Used for synchronizing doRestoreFinished during adb restore
    class AdbRestoreFinishedLatch implements BackupRestoreTask {
        static final String TAG = "AdbRestoreFinishedLatch";
        final CountDownLatch mLatch;
        private final int mCurrentOpToken;

        AdbRestoreFinishedLatch(int currentOpToken) {
            mLatch = new CountDownLatch(1);
            mCurrentOpToken = currentOpToken;
        }

        void await() {
            boolean latched = false;
            try {
                latched = mLatch.await(TIMEOUT_FULL_BACKUP_INTERVAL, TimeUnit.MILLISECONDS);
            } catch (InterruptedException e) {
                Slog.w(TAG, "Interrupted!");
            }
        }

        @Override
        public void execute() {
            // Unused
        }

        @Override
        public void operationComplete(long result) {
            if (MORE_DEBUG) {
                Slog.w(TAG, "adb onRestoreFinished() complete");
            }
            mLatch.countDown();
            removeOperation(mCurrentOpToken);
        }

        @Override
        public void handleCancel(boolean cancelAll) {
            if (DEBUG) {
                Slog.w(TAG, "adb onRestoreFinished() timed out");
            }
            mLatch.countDown();
            removeOperation(mCurrentOpToken);
        }
    }

    class PerformAdbRestoreTask implements Runnable {
        ParcelFileDescriptor mInputFile;
        String mCurrentPassword;
        String mDecryptPassword;
        IFullBackupRestoreObserver mObserver;
        AtomicBoolean mLatchObject;
        IBackupAgent mAgent;
        PackageManagerBackupAgent mPackageManagerBackupAgent;
        String mAgentPackage;
        ApplicationInfo mTargetApp;
        FullBackupObbConnection mObbConnection = null;
        ParcelFileDescriptor[] mPipes = null;
        byte[] mWidgetData = null;

        long mBytes;

        // Runner that can be placed on a separate thread to do in-process invocation
        // of the "restore finished" API asynchronously.  Used by adb restore.
        class RestoreFinishedRunnable implements Runnable {
            final IBackupAgent mAgent;
            final int mToken;

            RestoreFinishedRunnable(IBackupAgent agent, int token) {
                mAgent = agent;
                mToken = token;
            }

            @Override
            public void run() {
                try {
                    mAgent.doRestoreFinished(mToken, mBackupManagerBinder);
                } catch (RemoteException e) {
                    // never happens; this is used only for local binder calls
                }
            }
        }

        // possible handling states for a given package in the restore dataset
        final HashMap<String, RestorePolicy> mPackagePolicies
                = new HashMap<String, RestorePolicy>();

        // installer package names for each encountered app, derived from the manifests
        final HashMap<String, String> mPackageInstallers = new HashMap<String, String>();

        // Signatures for a given package found in its manifest file
        final HashMap<String, Signature[]> mManifestSignatures
                = new HashMap<String, Signature[]>();

        // Packages we've already wiped data on when restoring their first file
        final HashSet<String> mClearedPackages = new HashSet<String>();

        PerformAdbRestoreTask(ParcelFileDescriptor fd, String curPassword, String decryptPassword,
                IFullBackupRestoreObserver observer, AtomicBoolean latch) {
            mInputFile = fd;
            mCurrentPassword = curPassword;
            mDecryptPassword = decryptPassword;
            mObserver = observer;
            mLatchObject = latch;
            mAgent = null;
            mPackageManagerBackupAgent = makeMetadataAgent();
            mAgentPackage = null;
            mTargetApp = null;
            mObbConnection = new FullBackupObbConnection();

            // Which packages we've already wiped data on.  We prepopulate this
            // with a whitelist of packages known to be unclearable.
            mClearedPackages.add("android");
            mClearedPackages.add(SETTINGS_PACKAGE);
        }

        class RestoreFileRunnable implements Runnable {
            IBackupAgent mAgent;
            FileMetadata mInfo;
            ParcelFileDescriptor mSocket;
            int mToken;

            RestoreFileRunnable(IBackupAgent agent, FileMetadata info,
                    ParcelFileDescriptor socket, int token) throws IOException {
                mAgent = agent;
                mInfo = info;
                mToken = token;

                // This class is used strictly for process-local binder invocations.  The
                // semantics of ParcelFileDescriptor differ in this case; in particular, we
                // do not automatically get a 'dup'ed descriptor that we can can continue
                // to use asynchronously from the caller.  So, we make sure to dup it ourselves
                // before proceeding to do the restore.
                mSocket = ParcelFileDescriptor.dup(socket.getFileDescriptor());
            }

            @Override
            public void run() {
                try {
                    mAgent.doRestoreFile(mSocket, mInfo.size, mInfo.type,
                            mInfo.domain, mInfo.path, mInfo.mode, mInfo.mtime,
                            mToken, mBackupManagerBinder);
                } catch (RemoteException e) {
                    // never happens; this is used strictly for local binder calls
                }
            }
        }

        @Override
        public void run() {
            Slog.i(TAG, "--- Performing full-dataset restore ---");
            mObbConnection.establish();
            sendStartRestore();

            // Are we able to restore shared-storage data?
            if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
                mPackagePolicies.put(SHARED_BACKUP_AGENT_PACKAGE, RestorePolicy.ACCEPT);
            }

            FileInputStream rawInStream = null;
            DataInputStream rawDataIn = null;
            try {
                if (!backupPasswordMatches(mCurrentPassword)) {
                    if (DEBUG) Slog.w(TAG, "Backup password mismatch; aborting");
                    return;
                }

                mBytes = 0;
                byte[] buffer = new byte[32 * 1024];
                rawInStream = new FileInputStream(mInputFile.getFileDescriptor());
                rawDataIn = new DataInputStream(rawInStream);

                // First, parse out the unencrypted/uncompressed header
                boolean compressed = false;
                InputStream preCompressStream = rawInStream;
                final InputStream in;

                boolean okay = false;
                final int headerLen = BACKUP_FILE_HEADER_MAGIC.length();
                byte[] streamHeader = new byte[headerLen];
                rawDataIn.readFully(streamHeader);
                byte[] magicBytes = BACKUP_FILE_HEADER_MAGIC.getBytes("UTF-8");
                if (Arrays.equals(magicBytes, streamHeader)) {
                    // okay, header looks good.  now parse out the rest of the fields.
                    String s = readHeaderLine(rawInStream);
                    final int archiveVersion = Integer.parseInt(s);
                    if (archiveVersion <= BACKUP_FILE_VERSION) {
                        // okay, it's a version we recognize.  if it's version 1, we may need
                        // to try two different PBKDF2 regimes to compare checksums.
                        final boolean pbkdf2Fallback = (archiveVersion == 1);

                        s = readHeaderLine(rawInStream);
                        compressed = (Integer.parseInt(s) != 0);
                        s = readHeaderLine(rawInStream);
                        if (s.equals("none")) {
                            // no more header to parse; we're good to go
                            okay = true;
                        } else if (mDecryptPassword != null && mDecryptPassword.length() > 0) {
                            preCompressStream = decodeAesHeaderAndInitialize(s, pbkdf2Fallback,
                                    rawInStream);
                            if (preCompressStream != null) {
                                okay = true;
                            }
                        } else Slog.w(TAG, "Archive is encrypted but no password given");
                    } else Slog.w(TAG, "Wrong header version: " + s);
                } else Slog.w(TAG, "Didn't read the right header magic");

                if (!okay) {
                    Slog.w(TAG, "Invalid restore data; aborting.");
                    return;
                }

                // okay, use the right stream layer based on compression
                in = (compressed) ? new InflaterInputStream(preCompressStream) : preCompressStream;

                boolean didRestore;
                do {
                    didRestore = restoreOneFile(in, buffer);
                } while (didRestore);

                if (MORE_DEBUG) Slog.v(TAG, "Done consuming input tarfile, total bytes=" + mBytes);
            } catch (IOException e) {
                Slog.e(TAG, "Unable to read restore input");
            } finally {
                tearDownPipes();
                tearDownAgent(mTargetApp, true);

                try {
                    if (rawDataIn != null) rawDataIn.close();
                    if (rawInStream != null) rawInStream.close();
                    mInputFile.close();
                } catch (IOException e) {
                    Slog.w(TAG, "Close of restore data pipe threw", e);
                    /* nothing we can do about this */
                }
                synchronized (mLatchObject) {
                    mLatchObject.set(true);
                    mLatchObject.notifyAll();
                }
                mObbConnection.tearDown();
                sendEndRestore();
                Slog.d(TAG, "Full restore pass complete.");
                mWakelock.release();
            }
        }

        String readHeaderLine(InputStream in) throws IOException {
            int c;
            StringBuilder buffer = new StringBuilder(80);
            while ((c = in.read()) >= 0) {
                if (c == '\n') break;   // consume and discard the newlines
                buffer.append((char)c);
            }
            return buffer.toString();
        }

        InputStream attemptMasterKeyDecryption(String algorithm, byte[] userSalt, byte[] ckSalt,
                int rounds, String userIvHex, String masterKeyBlobHex, InputStream rawInStream,
                boolean doLog) {
            InputStream result = null;

            try {
                Cipher c = Cipher.getInstance("AES/CBC/PKCS5Padding");
                SecretKey userKey = buildPasswordKey(algorithm, mDecryptPassword, userSalt,
                        rounds);
                byte[] IV = hexToByteArray(userIvHex);
                IvParameterSpec ivSpec = new IvParameterSpec(IV);
                c.init(Cipher.DECRYPT_MODE,
                        new SecretKeySpec(userKey.getEncoded(), "AES"),
                        ivSpec);
                byte[] mkCipher = hexToByteArray(masterKeyBlobHex);
                byte[] mkBlob = c.doFinal(mkCipher);

                // first, the master key IV
                int offset = 0;
                int len = mkBlob[offset++];
                IV = Arrays.copyOfRange(mkBlob, offset, offset + len);
                offset += len;
                // then the master key itself
                len = mkBlob[offset++];
                byte[] mk = Arrays.copyOfRange(mkBlob,
                        offset, offset + len);
                offset += len;
                // and finally the master key checksum hash
                len = mkBlob[offset++];
                byte[] mkChecksum = Arrays.copyOfRange(mkBlob,
                        offset, offset + len);

                // now validate the decrypted master key against the checksum
                byte[] calculatedCk = makeKeyChecksum(algorithm, mk, ckSalt, rounds);
                if (Arrays.equals(calculatedCk, mkChecksum)) {
                    ivSpec = new IvParameterSpec(IV);
                    c.init(Cipher.DECRYPT_MODE,
                            new SecretKeySpec(mk, "AES"),
                            ivSpec);
                    // Only if all of the above worked properly will 'result' be assigned
                    result = new CipherInputStream(rawInStream, c);
                } else if (doLog) Slog.w(TAG, "Incorrect password");
            } catch (InvalidAlgorithmParameterException e) {
                if (doLog) Slog.e(TAG, "Needed parameter spec unavailable!", e);
            } catch (BadPaddingException e) {
                // This case frequently occurs when the wrong password is used to decrypt
                // the master key.  Use the identical "incorrect password" log text as is
                // used in the checksum failure log in order to avoid providing additional
                // information to an attacker.
                if (doLog) Slog.w(TAG, "Incorrect password");
            } catch (IllegalBlockSizeException e) {
                if (doLog) Slog.w(TAG, "Invalid block size in master key");
            } catch (NoSuchAlgorithmException e) {
                if (doLog) Slog.e(TAG, "Needed decryption algorithm unavailable!");
            } catch (NoSuchPaddingException e) {
                if (doLog) Slog.e(TAG, "Needed padding mechanism unavailable!");
            } catch (InvalidKeyException e) {
                if (doLog) Slog.w(TAG, "Illegal password; aborting");
            }

            return result;
        }

        InputStream decodeAesHeaderAndInitialize(String encryptionName, boolean pbkdf2Fallback,
                InputStream rawInStream) {
            InputStream result = null;
            try {
                if (encryptionName.equals(ENCRYPTION_ALGORITHM_NAME)) {

                    String userSaltHex = readHeaderLine(rawInStream); // 5
                    byte[] userSalt = hexToByteArray(userSaltHex);

                    String ckSaltHex = readHeaderLine(rawInStream); // 6
                    byte[] ckSalt = hexToByteArray(ckSaltHex);

                    int rounds = Integer.parseInt(readHeaderLine(rawInStream)); // 7
                    String userIvHex = readHeaderLine(rawInStream); // 8

                    String masterKeyBlobHex = readHeaderLine(rawInStream); // 9

                    // decrypt the master key blob
                    result = attemptMasterKeyDecryption(PBKDF_CURRENT, userSalt, ckSalt,
                            rounds, userIvHex, masterKeyBlobHex, rawInStream, false);
                    if (result == null && pbkdf2Fallback) {
                        result = attemptMasterKeyDecryption(PBKDF_FALLBACK, userSalt, ckSalt,
                                rounds, userIvHex, masterKeyBlobHex, rawInStream, true);
                    }
                } else Slog.w(TAG, "Unsupported encryption method: " + encryptionName);
            } catch (NumberFormatException e) {
                Slog.w(TAG, "Can't parse restore data header");
            } catch (IOException e) {
                Slog.w(TAG, "Can't read input header");
            }

            return result;
        }

        boolean restoreOneFile(InputStream instream, byte[] buffer) {
            FileMetadata info;
            try {
                info = readTarHeaders(instream);
                if (info != null) {
                    if (MORE_DEBUG) {
                        dumpFileMetadata(info);
                    }

                    final String pkg = info.packageName;
                    if (!pkg.equals(mAgentPackage)) {
                        // okay, change in package; set up our various
                        // bookkeeping if we haven't seen it yet
                        if (!mPackagePolicies.containsKey(pkg)) {
                            mPackagePolicies.put(pkg, RestorePolicy.IGNORE);
                        }

                        // Clean up the previous agent relationship if necessary,
                        // and let the observer know we're considering a new app.
                        if (mAgent != null) {
                            if (DEBUG) Slog.d(TAG, "Saw new package; finalizing old one");
                            // Now we're really done
                            tearDownPipes();
                            tearDownAgent(mTargetApp, true);
                            mTargetApp = null;
                            mAgentPackage = null;
                        }
                    }

                    if (info.path.equals(BACKUP_MANIFEST_FILENAME)) {
                        mPackagePolicies.put(pkg, readAppManifest(info, instream));
                        mPackageInstallers.put(pkg, info.installerPackageName);
                        // We've read only the manifest content itself at this point,
                        // so consume the footer before looping around to the next
                        // input file
                        skipTarPadding(info.size, instream);
                        sendOnRestorePackage(pkg);
                    } else if (info.path.equals(BACKUP_METADATA_FILENAME)) {
                        // Metadata blobs!
                        readMetadata(info, instream);
                        skipTarPadding(info.size, instream);
                    } else {
                        // Non-manifest, so it's actual file data.  Is this a package
                        // we're ignoring?
                        boolean okay = true;
                        RestorePolicy policy = mPackagePolicies.get(pkg);
                        switch (policy) {
                            case IGNORE:
                                okay = false;
                                break;

                            case ACCEPT_IF_APK:
                                // If we're in accept-if-apk state, then the first file we
                                // see MUST be the apk.
                                if (info.domain.equals(FullBackup.APK_TREE_TOKEN)) {
                                    if (DEBUG) Slog.d(TAG, "APK file; installing");
                                    // Try to install the app.
                                    String installerName = mPackageInstallers.get(pkg);
                                    okay = installApk(info, installerName, instream);
                                    // good to go; promote to ACCEPT
                                    mPackagePolicies.put(pkg, (okay)
                                            ? RestorePolicy.ACCEPT
                                            : RestorePolicy.IGNORE);
                                    // At this point we've consumed this file entry
                                    // ourselves, so just strip the tar footer and
                                    // go on to the next file in the input stream
                                    skipTarPadding(info.size, instream);
                                    return true;
                                } else {
                                    // File data before (or without) the apk.  We can't
                                    // handle it coherently in this case so ignore it.
                                    mPackagePolicies.put(pkg, RestorePolicy.IGNORE);
                                    okay = false;
                                }
                                break;

                            case ACCEPT:
                                if (info.domain.equals(FullBackup.APK_TREE_TOKEN)) {
                                    if (DEBUG) Slog.d(TAG, "apk present but ACCEPT");
                                    // we can take the data without the apk, so we
                                    // *want* to do so.  skip the apk by declaring this
                                    // one file not-okay without changing the restore
                                    // policy for the package.
                                    okay = false;
                                }
                                break;

                            default:
                                // Something has gone dreadfully wrong when determining
                                // the restore policy from the manifest.  Ignore the
                                // rest of this package's data.
                                Slog.e(TAG, "Invalid policy from manifest");
                                okay = false;
                                mPackagePolicies.put(pkg, RestorePolicy.IGNORE);
                                break;
                        }

                        // The path needs to be canonical
                        if (info.path.contains("..") || info.path.contains("//")) {
                            if (MORE_DEBUG) {
                                Slog.w(TAG, "Dropping invalid path " + info.path);
                            }
                            okay = false;
                        }

                        // If the policy is satisfied, go ahead and set up to pipe the
                        // data to the agent.
                        if (DEBUG && okay && mAgent != null) {
                            Slog.i(TAG, "Reusing existing agent instance");
                        }
                        if (okay && mAgent == null) {
                            if (DEBUG) Slog.d(TAG, "Need to launch agent for " + pkg);

                            try {
                                mTargetApp = mPackageManager.getApplicationInfo(pkg, 0);

                                // If we haven't sent any data to this app yet, we probably
                                // need to clear it first.  Check that.
                                if (!mClearedPackages.contains(pkg)) {
                                    // apps with their own backup agents are
                                    // responsible for coherently managing a full
                                    // restore.
                                    if (mTargetApp.backupAgentName == null) {
                                        if (DEBUG) Slog.d(TAG, "Clearing app data preparatory to full restore");
                                        clearApplicationDataSynchronous(pkg);
                                    } else {
                                        if (DEBUG) Slog.d(TAG, "backup agent ("
                                                + mTargetApp.backupAgentName + ") => no clear");
                                    }
                                    mClearedPackages.add(pkg);
                                } else {
                                    if (DEBUG) Slog.d(TAG, "We've initialized this app already; no clear required");
                                }

                                // All set; now set up the IPC and launch the agent
                                setUpPipes();
                                mAgent = bindToAgentSynchronous(mTargetApp,
                                        FullBackup.KEY_VALUE_DATA_TOKEN.equals(info.domain)
                                                ? ApplicationThreadConstants.BACKUP_MODE_INCREMENTAL
                                                : ApplicationThreadConstants.BACKUP_MODE_RESTORE_FULL);
                                mAgentPackage = pkg;
                            } catch (IOException e) {
                                // fall through to error handling
                            } catch (NameNotFoundException e) {
                                // fall through to error handling
                            }

                            if (mAgent == null) {
                                if (DEBUG) Slog.d(TAG, "Unable to create agent for " + pkg);
                                okay = false;
                                tearDownPipes();
                                mPackagePolicies.put(pkg, RestorePolicy.IGNORE);
                            }
                        }

                        // Sanity check: make sure we never give data to the wrong app.  This
                        // should never happen but a little paranoia here won't go amiss.
                        if (okay && !pkg.equals(mAgentPackage)) {
                            Slog.e(TAG, "Restoring data for " + pkg
                                    + " but agent is for " + mAgentPackage);
                            okay = false;
                        }

                        // At this point we have an agent ready to handle the full
                        // restore data as well as a pipe for sending data to
                        // that agent.  Tell the agent to start reading from the
                        // pipe.
                        if (okay) {
                            boolean agentSuccess = true;
                            long toCopy = info.size;
                            final boolean isSharedStorage = pkg.equals(SHARED_BACKUP_AGENT_PACKAGE);
                            final long timeout = isSharedStorage ?
                                    TIMEOUT_SHARED_BACKUP_INTERVAL : TIMEOUT_RESTORE_INTERVAL;
                            final int token = generateRandomIntegerToken();
                            try {
                                prepareOperationTimeout(token, timeout, null,
                                        OP_TYPE_RESTORE_WAIT);
                                if (FullBackup.OBB_TREE_TOKEN.equals(info.domain)) {
                                    if (DEBUG) Slog.d(TAG, "Restoring OBB file for " + pkg
                                            + " : " + info.path);
                                    mObbConnection.restoreObbFile(pkg, mPipes[0],
                                            info.size, info.type, info.path, info.mode,
                                            info.mtime, token, mBackupManagerBinder);
                                } else if (FullBackup.KEY_VALUE_DATA_TOKEN.equals(info.domain)) {
                                    if (DEBUG) Slog.d(TAG, "Restoring key-value file for " + pkg
                                            + " : " + info.path);
                                    KeyValueAdbRestoreEngine restoreEngine =
                                            new KeyValueAdbRestoreEngine(BackupManagerService.this,
                                                    mDataDir, info, mPipes[0], mAgent, token);
                                    new Thread(restoreEngine, "restore-key-value-runner").start();
                                } else {
                                    if (DEBUG) Slog.d(TAG, "Invoking agent to restore file "
                                            + info.path);
                                    // fire up the app's agent listening on the socket.  If
                                    // the agent is running in the system process we can't
                                    // just invoke it asynchronously, so we provide a thread
                                    // for it here.
                                    if (mTargetApp.processName.equals("system")) {
                                        Slog.d(TAG, "system process agent - spinning a thread");
                                        RestoreFileRunnable runner = new RestoreFileRunnable(
                                                mAgent, info, mPipes[0], token);
                                        new Thread(runner, "restore-sys-runner").start();
                                    } else {
                                        mAgent.doRestoreFile(mPipes[0], info.size, info.type,
                                                info.domain, info.path, info.mode, info.mtime,
                                                token, mBackupManagerBinder);
                                    }
                                }
                            } catch (IOException e) {
                                // couldn't dup the socket for a process-local restore
                                Slog.d(TAG, "Couldn't establish restore");
                                agentSuccess = false;
                                okay = false;
                            } catch (RemoteException e) {
                                // whoops, remote entity went away.  We'll eat the content
                                // ourselves, then, and not copy it over.
                                Slog.e(TAG, "Agent crashed during full restore");
                                agentSuccess = false;
                                okay = false;
                            }

                            // Copy over the data if the agent is still good
                            if (okay) {
                                boolean pipeOkay = true;
                                FileOutputStream pipe = new FileOutputStream(
                                        mPipes[1].getFileDescriptor());
                                while (toCopy > 0) {
                                    int toRead = (toCopy > buffer.length)
                                    ? buffer.length : (int)toCopy;
                                    int nRead = instream.read(buffer, 0, toRead);
                                    if (nRead >= 0) mBytes += nRead;
                                    if (nRead <= 0) break;
                                    toCopy -= nRead;

                                    // send it to the output pipe as long as things
                                    // are still good
                                    if (pipeOkay) {
                                        try {
                                            pipe.write(buffer, 0, nRead);
                                        } catch (IOException e) {
                                            Slog.e(TAG, "Failed to write to restore pipe", e);
                                            pipeOkay = false;
                                        }
                                    }
                                }

                                // done sending that file!  Now we just need to consume
                                // the delta from info.size to the end of block.
                                skipTarPadding(info.size, instream);

                                // and now that we've sent it all, wait for the remote
                                // side to acknowledge receipt
                                agentSuccess = waitUntilOperationComplete(token);
                            }

                            // okay, if the remote end failed at any point, deal with
                            // it by ignoring the rest of the restore on it
                            if (!agentSuccess) {
                                if (DEBUG) {
                                    Slog.d(TAG, "Agent failure restoring " + pkg + "; now ignoring");
                                }
                                mBackupHandler.removeMessages(MSG_RESTORE_OPERATION_TIMEOUT);
                                tearDownPipes();
                                tearDownAgent(mTargetApp, false);
                                mPackagePolicies.put(pkg, RestorePolicy.IGNORE);
                            }
                        }

                        // Problems setting up the agent communication, or an already-
                        // ignored package: skip to the next tar stream entry by
                        // reading and discarding this file.
                        if (!okay) {
                            if (DEBUG) Slog.d(TAG, "[discarding file content]");
                            long bytesToConsume = (info.size + 511) & ~511;
                            while (bytesToConsume > 0) {
                                int toRead = (bytesToConsume > buffer.length)
                                ? buffer.length : (int)bytesToConsume;
                                long nRead = instream.read(buffer, 0, toRead);
                                if (nRead >= 0) mBytes += nRead;
                                if (nRead <= 0) break;
                                bytesToConsume -= nRead;
                            }
                        }
                    }
                }
            } catch (IOException e) {
                if (DEBUG) Slog.w(TAG, "io exception on restore socket read", e);
                // treat as EOF
                info = null;
            }

            return (info != null);
        }

        void setUpPipes() throws IOException {
            mPipes = ParcelFileDescriptor.createPipe();
        }

        void tearDownPipes() {
            if (mPipes != null) {
                try {
                    mPipes[0].close();
                    mPipes[0] = null;
                    mPipes[1].close();
                    mPipes[1] = null;
                } catch (IOException e) {
                    Slog.w(TAG, "Couldn't close agent pipes", e);
                }
                mPipes = null;
            }
        }

        void tearDownAgent(ApplicationInfo app, boolean doRestoreFinished) {
            if (mAgent != null) {
                try {
                    // In the adb restore case, we do restore-finished here
                    if (doRestoreFinished) {
                        final int token = generateRandomIntegerToken();
                        final AdbRestoreFinishedLatch latch = new AdbRestoreFinishedLatch(token);
                        prepareOperationTimeout(token, TIMEOUT_FULL_BACKUP_INTERVAL, latch,
                                OP_TYPE_RESTORE_WAIT);
                        if (mTargetApp.processName.equals("system")) {
                            if (MORE_DEBUG) {
                                Slog.d(TAG, "system agent - restoreFinished on thread");
                            }
                            Runnable runner = new RestoreFinishedRunnable(mAgent, token);
                            new Thread(runner, "restore-sys-finished-runner").start();
                        } else {
                            mAgent.doRestoreFinished(token, mBackupManagerBinder);
                        }

                        latch.await();
                    }

                    // unbind and tidy up even on timeout or failure, just in case
                    mActivityManager.unbindBackupAgent(app);

                    // The agent was running with a stub Application object, so shut it down.
                    // !!! We hardcode the confirmation UI's package name here rather than use a
                    //     manifest flag!  TODO something less direct.
                    if (app.uid >= Process.FIRST_APPLICATION_UID
                            && !app.packageName.equals("com.android.backupconfirm")) {
                        if (DEBUG) Slog.d(TAG, "Killing host process");
                        mActivityManager.killApplicationProcess(app.processName, app.uid);
                    } else {
                        if (DEBUG) Slog.d(TAG, "Not killing after full restore");
                    }
                } catch (RemoteException e) {
                    Slog.d(TAG, "Lost app trying to shut down");
                }
                mAgent = null;
            }
        }

        class RestoreInstallObserver extends PackageInstallObserver {
            final AtomicBoolean mDone = new AtomicBoolean();
            String mPackageName;
            int mResult;

            public void reset() {
                synchronized (mDone) {
                    mDone.set(false);
                }
            }

            public void waitForCompletion() {
                synchronized (mDone) {
                    while (mDone.get() == false) {
                        try {
                            mDone.wait();
                        } catch (InterruptedException e) { }
                    }
                }
            }

            int getResult() {
                return mResult;
            }

            @Override
            public void onPackageInstalled(String packageName, int returnCode,
                    String msg, Bundle extras) {
                synchronized (mDone) {
                    mResult = returnCode;
                    mPackageName = packageName;
                    mDone.set(true);
                    mDone.notifyAll();
                }
            }
        }

        class RestoreDeleteObserver extends IPackageDeleteObserver.Stub {
            final AtomicBoolean mDone = new AtomicBoolean();
            int mResult;

            public void reset() {
                synchronized (mDone) {
                    mDone.set(false);
                }
            }

            public void waitForCompletion() {
                synchronized (mDone) {
                    while (mDone.get() == false) {
                        try {
                            mDone.wait();
                        } catch (InterruptedException e) { }
                    }
                }
            }

            @Override
            public void packageDeleted(String packageName, int returnCode) throws RemoteException {
                synchronized (mDone) {
                    mResult = returnCode;
                    mDone.set(true);
                    mDone.notifyAll();
                }
            }
        }

        final RestoreInstallObserver mInstallObserver = new RestoreInstallObserver();
        final RestoreDeleteObserver mDeleteObserver = new RestoreDeleteObserver();

        boolean installApk(FileMetadata info, String installerPackage, InputStream instream) {
            boolean okay = true;

            if (DEBUG) Slog.d(TAG, "Installing from backup: " + info.packageName);

            // The file content is an .apk file.  Copy it out to a staging location and
            // attempt to install it.
            File apkFile = new File(mDataDir, info.packageName);
            try {
                FileOutputStream apkStream = new FileOutputStream(apkFile);
                byte[] buffer = new byte[32 * 1024];
                long size = info.size;
                while (size > 0) {
                    long toRead = (buffer.length < size) ? buffer.length : size;
                    int didRead = instream.read(buffer, 0, (int)toRead);
                    if (didRead >= 0) mBytes += didRead;
                    apkStream.write(buffer, 0, didRead);
                    size -= didRead;
                }
                apkStream.close();

                // make sure the installer can read it
                apkFile.setReadable(true, false);

                // Now install it
                Uri packageUri = Uri.fromFile(apkFile);
                mInstallObserver.reset();
                mPackageManager.installPackage(packageUri, mInstallObserver,
                        PackageManager.INSTALL_REPLACE_EXISTING | PackageManager.INSTALL_FROM_ADB,
                        installerPackage);
                mInstallObserver.waitForCompletion();

                if (mInstallObserver.getResult() != PackageManager.INSTALL_SUCCEEDED) {
                    // The only time we continue to accept install of data even if the
                    // apk install failed is if we had already determined that we could
                    // accept the data regardless.
                    if (mPackagePolicies.get(info.packageName) != RestorePolicy.ACCEPT) {
                        okay = false;
                    }
                } else {
                    // Okay, the install succeeded.  Make sure it was the right app.
                    boolean uninstall = false;
                    if (!mInstallObserver.mPackageName.equals(info.packageName)) {
                        Slog.w(TAG, "Restore stream claimed to include apk for "
                                + info.packageName + " but apk was really "
                                + mInstallObserver.mPackageName);
                        // delete the package we just put in place; it might be fraudulent
                        okay = false;
                        uninstall = true;
                    } else {
                        try {
                            PackageInfo pkg = mPackageManager.getPackageInfo(info.packageName,
                                    PackageManager.GET_SIGNATURES);
                            if ((pkg.applicationInfo.flags & ApplicationInfo.FLAG_ALLOW_BACKUP) == 0) {
                                Slog.w(TAG, "Restore stream contains apk of package "
                                        + info.packageName + " but it disallows backup/restore");
                                okay = false;
                            } else {
                                // So far so good -- do the signatures match the manifest?
                                Signature[] sigs = mManifestSignatures.get(info.packageName);
                                if (signaturesMatch(sigs, pkg)) {
                                    // If this is a system-uid app without a declared backup agent,
                                    // don't restore any of the file data.
                                    if ((pkg.applicationInfo.uid < Process.FIRST_APPLICATION_UID)
                                            && (pkg.applicationInfo.backupAgentName == null)) {
                                        Slog.w(TAG, "Installed app " + info.packageName
                                                + " has restricted uid and no agent");
                                        okay = false;
                                    }
                                } else {
                                    Slog.w(TAG, "Installed app " + info.packageName
                                            + " signatures do not match restore manifest");
                                    okay = false;
                                    uninstall = true;
                                }
                            }
                        } catch (NameNotFoundException e) {
                            Slog.w(TAG, "Install of package " + info.packageName
                                    + " succeeded but now not found");
                            okay = false;
                        }
                    }

                    // If we're not okay at this point, we need to delete the package
                    // that we just installed.
                    if (uninstall) {
                        mDeleteObserver.reset();
                        mPackageManager.deletePackage(mInstallObserver.mPackageName,
                                mDeleteObserver, 0);
                        mDeleteObserver.waitForCompletion();
                    }
                }
            } catch (IOException e) {
                Slog.e(TAG, "Unable to transcribe restored apk for install");
                okay = false;
            } finally {
                apkFile.delete();
            }

            return okay;
        }

        // Given an actual file content size, consume the post-content padding mandated
        // by the tar format.
        void skipTarPadding(long size, InputStream instream) throws IOException {
            long partial = (size + 512) % 512;
            if (partial > 0) {
                final int needed = 512 - (int)partial;
                byte[] buffer = new byte[needed];
                if (readExactly(instream, buffer, 0, needed) == needed) {
                    mBytes += needed;
                } else throw new IOException("Unexpected EOF in padding");
            }
        }

        // Read a widget metadata file, returning the restored blob
        void readMetadata(FileMetadata info, InputStream instream) throws IOException {
            // Fail on suspiciously large widget dump files
            if (info.size > 64 * 1024) {
                throw new IOException("Metadata too big; corrupt? size=" + info.size);
            }

            byte[] buffer = new byte[(int) info.size];
            if (readExactly(instream, buffer, 0, (int)info.size) == info.size) {
                mBytes += info.size;
            } else throw new IOException("Unexpected EOF in widget data");

            String[] str = new String[1];
            int offset = extractLine(buffer, 0, str);
            int version = Integer.parseInt(str[0]);
            if (version == BACKUP_MANIFEST_VERSION) {
                offset = extractLine(buffer, offset, str);
                final String pkg = str[0];
                if (info.packageName.equals(pkg)) {
                    // Data checks out -- the rest of the buffer is a concatenation of
                    // binary blobs as described in the comment at writeAppWidgetData()
                    ByteArrayInputStream bin = new ByteArrayInputStream(buffer,
                            offset, buffer.length - offset);
                    DataInputStream in = new DataInputStream(bin);
                    while (bin.available() > 0) {
                        int token = in.readInt();
                        int size = in.readInt();
                        if (size > 64 * 1024) {
                            throw new IOException("Datum "
                                    + Integer.toHexString(token)
                                    + " too big; corrupt? size=" + info.size);
                        }
                        switch (token) {
                            case BACKUP_WIDGET_METADATA_TOKEN:
                            {
                                if (MORE_DEBUG) {
                                    Slog.i(TAG, "Got widget metadata for " + info.packageName);
                                }
                                mWidgetData = new byte[size];
                                in.read(mWidgetData);
                                break;
                            }
                            default:
                            {
                                if (DEBUG) {
                                    Slog.i(TAG, "Ignoring metadata blob "
                                            + Integer.toHexString(token)
                                            + " for " + info.packageName);
                                }
                                in.skipBytes(size);
                                break;
                            }
                        }
                    }
                } else {
                    Slog.w(TAG, "Metadata mismatch: package " + info.packageName
                            + " but widget data for " + pkg);
                }
            } else {
                Slog.w(TAG, "Unsupported metadata version " + version);
            }
        }

        // Returns a policy constant; takes a buffer arg to reduce memory churn
        RestorePolicy readAppManifest(FileMetadata info, InputStream instream)
                throws IOException {
            // Fail on suspiciously large manifest files
            if (info.size > 64 * 1024) {
                throw new IOException("Restore manifest too big; corrupt? size=" + info.size);
            }

            byte[] buffer = new byte[(int) info.size];
            if (readExactly(instream, buffer, 0, (int)info.size) == info.size) {
                mBytes += info.size;
            } else throw new IOException("Unexpected EOF in manifest");

            RestorePolicy policy = RestorePolicy.IGNORE;
            String[] str = new String[1];
            int offset = 0;

            try {
                offset = extractLine(buffer, offset, str);
                int version = Integer.parseInt(str[0]);
                if (version == BACKUP_MANIFEST_VERSION) {
                    offset = extractLine(buffer, offset, str);
                    String manifestPackage = str[0];
                    // TODO: handle <original-package>
                    if (manifestPackage.equals(info.packageName)) {
                        offset = extractLine(buffer, offset, str);
                        version = Integer.parseInt(str[0]);  // app version
                        offset = extractLine(buffer, offset, str);
                        // This is the platform version, which we don't use, but we parse it
                        // as a safety against corruption in the manifest.
                        Integer.parseInt(str[0]);
                        offset = extractLine(buffer, offset, str);
                        info.installerPackageName = (str[0].length() > 0) ? str[0] : null;
                        offset = extractLine(buffer, offset, str);
                        boolean hasApk = str[0].equals("1");
                        offset = extractLine(buffer, offset, str);
                        int numSigs = Integer.parseInt(str[0]);
                        if (numSigs > 0) {
                            Signature[] sigs = new Signature[numSigs];
                            for (int i = 0; i < numSigs; i++) {
                                offset = extractLine(buffer, offset, str);
                                sigs[i] = new Signature(str[0]);
                            }
                            mManifestSignatures.put(info.packageName, sigs);

                            // Okay, got the manifest info we need...
                            try {
                                PackageInfo pkgInfo = mPackageManager.getPackageInfo(
                                        info.packageName, PackageManager.GET_SIGNATURES);
                                // Fall through to IGNORE if the app explicitly disallows backup
                                final int flags = pkgInfo.applicationInfo.flags;
                                if ((flags & ApplicationInfo.FLAG_ALLOW_BACKUP) != 0) {
                                    // Restore system-uid-space packages only if they have
                                    // defined a custom backup agent
                                    if ((pkgInfo.applicationInfo.uid >= Process.FIRST_APPLICATION_UID)
                                            || (pkgInfo.applicationInfo.backupAgentName != null)) {
                                        // Verify signatures against any installed version; if they
                                        // don't match, then we fall though and ignore the data.  The
                                        // signatureMatch() method explicitly ignores the signature
                                        // check for packages installed on the system partition, because
                                        // such packages are signed with the platform cert instead of
                                        // the app developer's cert, so they're different on every
                                        // device.
                                        if (signaturesMatch(sigs, pkgInfo)) {
                                            if ((pkgInfo.applicationInfo.flags
                                                    & ApplicationInfo.FLAG_RESTORE_ANY_VERSION) != 0) {
                                                Slog.i(TAG, "Package has restoreAnyVersion; taking data");
                                                policy = RestorePolicy.ACCEPT;
                                            } else if (pkgInfo.versionCode >= version) {
                                                Slog.i(TAG, "Sig + version match; taking data");
                                                policy = RestorePolicy.ACCEPT;
                                            } else {
                                                // The data is from a newer version of the app than
                                                // is presently installed.  That means we can only
                                                // use it if the matching apk is also supplied.
                                                Slog.d(TAG, "Data version " + version
                                                        + " is newer than installed version "
                                                        + pkgInfo.versionCode + " - requiring apk");
                                                policy = RestorePolicy.ACCEPT_IF_APK;
                                            }
                                        } else {
                                            Slog.w(TAG, "Restore manifest signatures do not match "
                                                    + "installed application for " + info.packageName);
                                        }
                                    } else {
                                        Slog.w(TAG, "Package " + info.packageName
                                                + " is system level with no agent");
                                    }
                                } else {
                                    if (DEBUG) Slog.i(TAG, "Restore manifest from "
                                            + info.packageName + " but allowBackup=false");
                                }
                            } catch (NameNotFoundException e) {
                                // Okay, the target app isn't installed.  We can process
                                // the restore properly only if the dataset provides the
                                // apk file and we can successfully install it.
                                if (DEBUG) Slog.i(TAG, "Package " + info.packageName
                                        + " not installed; requiring apk in dataset");
                                policy = RestorePolicy.ACCEPT_IF_APK;
                            }

                            if (policy == RestorePolicy.ACCEPT_IF_APK && !hasApk) {
                                Slog.i(TAG, "Cannot restore package " + info.packageName
                                        + " without the matching .apk");
                            }
                        } else {
                            Slog.i(TAG, "Missing signature on backed-up package "
                                    + info.packageName);
                        }
                    } else {
                        Slog.i(TAG, "Expected package " + info.packageName
                                + " but restore manifest claims " + manifestPackage);
                    }
                } else {
                    Slog.i(TAG, "Unknown restore manifest version " + version
                            + " for package " + info.packageName);
                }
            } catch (NumberFormatException e) {
                Slog.w(TAG, "Corrupt restore manifest for package " + info.packageName);
            } catch (IllegalArgumentException e) {
                Slog.w(TAG, e.getMessage());
            }

            return policy;
        }

        // Builds a line from a byte buffer starting at 'offset', and returns
        // the index of the next unconsumed data in the buffer.
        int extractLine(byte[] buffer, int offset, String[] outStr) throws IOException {
            final int end = buffer.length;
            if (offset >= end) throw new IOException("Incomplete data");

            int pos;
            for (pos = offset; pos < end; pos++) {
                byte c = buffer[pos];
                // at LF we declare end of line, and return the next char as the
                // starting point for the next time through
                if (c == '\n') {
                    break;
                }
            }
            outStr[0] = new String(buffer, offset, pos - offset);
            pos++;  // may be pointing an extra byte past the end but that's okay
            return pos;
        }

        void dumpFileMetadata(FileMetadata info) {
            if (DEBUG) {
                StringBuilder b = new StringBuilder(128);

                // mode string
                b.append((info.type == BackupAgent.TYPE_DIRECTORY) ? 'd' : '-');
                b.append(((info.mode & 0400) != 0) ? 'r' : '-');
                b.append(((info.mode & 0200) != 0) ? 'w' : '-');
                b.append(((info.mode & 0100) != 0) ? 'x' : '-');
                b.append(((info.mode & 0040) != 0) ? 'r' : '-');
                b.append(((info.mode & 0020) != 0) ? 'w' : '-');
                b.append(((info.mode & 0010) != 0) ? 'x' : '-');
                b.append(((info.mode & 0004) != 0) ? 'r' : '-');
                b.append(((info.mode & 0002) != 0) ? 'w' : '-');
                b.append(((info.mode & 0001) != 0) ? 'x' : '-');
                b.append(String.format(" %9d ", info.size));

                Date stamp = new Date(info.mtime);
                b.append(new SimpleDateFormat("MMM dd HH:mm:ss ").format(stamp));

                b.append(info.packageName);
                b.append(" :: ");
                b.append(info.domain);
                b.append(" :: ");
                b.append(info.path);

                Slog.i(TAG, b.toString());
            }
        }

        // Consume a tar file header block [sequence] and accumulate the relevant metadata
        FileMetadata readTarHeaders(InputStream instream) throws IOException {
            byte[] block = new byte[512];
            FileMetadata info = null;

            boolean gotHeader = readTarHeader(instream, block);
            if (gotHeader) {
                try {
                    // okay, presume we're okay, and extract the various metadata
                    info = new FileMetadata();
                    info.size = extractRadix(block, 124, 12, 8);
                    info.mtime = extractRadix(block, 136, 12, 8);
                    info.mode = extractRadix(block, 100, 8, 8);

                    info.path = extractString(block, 345, 155); // prefix
                    String path = extractString(block, 0, 100);
                    if (path.length() > 0) {
                        if (info.path.length() > 0) info.path += '/';
                        info.path += path;
                    }

                    // tar link indicator field: 1 byte at offset 156 in the header.
                    int typeChar = block[156];
                    if (typeChar == 'x') {
                        // pax extended header, so we need to read that
                        gotHeader = readPaxExtendedHeader(instream, info);
                        if (gotHeader) {
                            // and after a pax extended header comes another real header -- read
                            // that to find the real file type
                            gotHeader = readTarHeader(instream, block);
                        }
                        if (!gotHeader) throw new IOException("Bad or missing pax header");

                        typeChar = block[156];
                    }

                    switch (typeChar) {
                        case '0': info.type = BackupAgent.TYPE_FILE; break;
                        case '5': {
                            info.type = BackupAgent.TYPE_DIRECTORY;
                            if (info.size != 0) {
                                Slog.w(TAG, "Directory entry with nonzero size in header");
                                info.size = 0;
                            }
                            break;
                        }
                        case 0: {
                            // presume EOF
                            if (DEBUG) Slog.w(TAG, "Saw type=0 in tar header block, info=" + info);
                            return null;
                        }
                        default: {
                            Slog.e(TAG, "Unknown tar entity type: " + typeChar);
                            throw new IOException("Unknown entity type " + typeChar);
                        }
                    }

                    // Parse out the path
                    //
                    // first: apps/shared/unrecognized
                    if (FullBackup.SHARED_PREFIX.regionMatches(0,
                            info.path, 0, FullBackup.SHARED_PREFIX.length())) {
                        // File in shared storage.  !!! TODO: implement this.
                        info.path = info.path.substring(FullBackup.SHARED_PREFIX.length());
                        info.packageName = SHARED_BACKUP_AGENT_PACKAGE;
                        info.domain = FullBackup.SHARED_STORAGE_TOKEN;
                        if (DEBUG) Slog.i(TAG, "File in shared storage: " + info.path);
                    } else if (FullBackup.APPS_PREFIX.regionMatches(0,
                            info.path, 0, FullBackup.APPS_PREFIX.length())) {
                        // App content!  Parse out the package name and domain

                        // strip the apps/ prefix
                        info.path = info.path.substring(FullBackup.APPS_PREFIX.length());

                        // extract the package name
                        int slash = info.path.indexOf('/');
                        if (slash < 0) throw new IOException("Illegal semantic path in " + info.path);
                        info.packageName = info.path.substring(0, slash);
                        info.path = info.path.substring(slash+1);

                        // if it's a manifest or metadata payload we're done, otherwise parse
                        // out the domain into which the file will be restored
                        if (!info.path.equals(BACKUP_MANIFEST_FILENAME)
                                && !info.path.equals(BACKUP_METADATA_FILENAME)) {
                            slash = info.path.indexOf('/');
                            if (slash < 0) throw new IOException("Illegal semantic path in non-manifest " + info.path);
                            info.domain = info.path.substring(0, slash);
                            info.path = info.path.substring(slash + 1);
                        }
                    }
                } catch (IOException e) {
                    if (DEBUG) {
                        Slog.e(TAG, "Parse error in header: " + e.getMessage());
                        HEXLOG(block);
                    }
                    throw e;
                }
            }
            return info;
        }

        private void HEXLOG(byte[] block) {
            int offset = 0;
            int todo = block.length;
            StringBuilder buf = new StringBuilder(64);
            while (todo > 0) {
                buf.append(String.format("%04x   ", offset));
                int numThisLine = (todo > 16) ? 16 : todo;
                for (int i = 0; i < numThisLine; i++) {
                    buf.append(String.format("%02x ", block[offset+i]));
                }
                Slog.i("hexdump", buf.toString());
                buf.setLength(0);
                todo -= numThisLine;
                offset += numThisLine;
            }
        }

        // Read exactly the given number of bytes into a buffer at the stated offset.
        // Returns false if EOF is encountered before the requested number of bytes
        // could be read.
        int readExactly(InputStream in, byte[] buffer, int offset, int size)
                throws IOException {
            if (size <= 0) throw new IllegalArgumentException("size must be > 0");

            int soFar = 0;
            while (soFar < size) {
                int nRead = in.read(buffer, offset + soFar, size - soFar);
                if (nRead <= 0) {
                    if (MORE_DEBUG) Slog.w(TAG, "- wanted exactly " + size + " but got only " + soFar);
                    break;
                }
                soFar += nRead;
            }
            return soFar;
        }

        boolean readTarHeader(InputStream instream, byte[] block) throws IOException {
            final int got = readExactly(instream, block, 0, 512);
            if (got == 0) return false;     // Clean EOF
            if (got < 512) throw new IOException("Unable to read full block header");
            mBytes += 512;
            return true;
        }

        // overwrites 'info' fields based on the pax extended header
        boolean readPaxExtendedHeader(InputStream instream, FileMetadata info)
                throws IOException {
            // We should never see a pax extended header larger than this
            if (info.size > 32*1024) {
                Slog.w(TAG, "Suspiciously large pax header size " + info.size
                        + " - aborting");
                throw new IOException("Sanity failure: pax header size " + info.size);
            }

            // read whole blocks, not just the content size
            int numBlocks = (int)((info.size + 511) >> 9);
            byte[] data = new byte[numBlocks * 512];
            if (readExactly(instream, data, 0, data.length) < data.length) {
                throw new IOException("Unable to read full pax header");
            }
            mBytes += data.length;

            final int contentSize = (int) info.size;
            int offset = 0;
            do {
                // extract the line at 'offset'
                int eol = offset+1;
                while (eol < contentSize && data[eol] != ' ') eol++;
                if (eol >= contentSize) {
                    // error: we just hit EOD looking for the end of the size field
                    throw new IOException("Invalid pax data");
                }
                // eol points to the space between the count and the key
                int linelen = (int) extractRadix(data, offset, eol - offset, 10);
                int key = eol + 1;  // start of key=value
                eol = offset + linelen - 1; // trailing LF
                int value;
                for (value = key+1; data[value] != '=' && value <= eol; value++);
                if (value > eol) {
                    throw new IOException("Invalid pax declaration");
                }

                // pax requires that key/value strings be in UTF-8
                String keyStr = new String(data, key, value-key, "UTF-8");
                // -1 to strip the trailing LF
                String valStr = new String(data, value+1, eol-value-1, "UTF-8");

                if ("path".equals(keyStr)) {
                    info.path = valStr;
                } else if ("size".equals(keyStr)) {
                    info.size = Long.parseLong(valStr);
                } else {
                    if (DEBUG) Slog.i(TAG, "Unhandled pax key: " + key);
                }

                offset += linelen;
            } while (offset < contentSize);

            return true;
        }

        long extractRadix(byte[] data, int offset, int maxChars, int radix)
                throws IOException {
            long value = 0;
            final int end = offset + maxChars;
            for (int i = offset; i < end; i++) {
                final byte b = data[i];
                // Numeric fields in tar can terminate with either NUL or SPC
                if (b == 0 || b == ' ') break;
                if (b < '0' || b > ('0' + radix - 1)) {
                    throw new IOException("Invalid number in header: '" + (char)b + "' for radix " + radix);
                }
                value = radix * value + (b - '0');
            }
            return value;
        }

        String extractString(byte[] data, int offset, int maxChars) throws IOException {
            final int end = offset + maxChars;
            int eos = offset;
            // tar string fields terminate early with a NUL
            while (eos < end && data[eos] != 0) eos++;
            return new String(data, offset, eos-offset, "US-ASCII");
        }

        void sendStartRestore() {
            if (mObserver != null) {
                try {
                    mObserver.onStartRestore();
                } catch (RemoteException e) {
                    Slog.w(TAG, "full restore observer went away: startRestore");
                    mObserver = null;
                }
            }
        }

        void sendOnRestorePackage(String name) {
            if (mObserver != null) {
                try {
                    // TODO: use a more user-friendly name string
                    mObserver.onRestorePackage(name);
                } catch (RemoteException e) {
                    Slog.w(TAG, "full restore observer went away: restorePackage");
                    mObserver = null;
                }
            }
        }

        void sendEndRestore() {
            if (mObserver != null) {
                try {
                    mObserver.onEndRestore();
                } catch (RemoteException e) {
                    Slog.w(TAG, "full restore observer went away: endRestore");
                    mObserver = null;
                }
            }
        }
    }

    // ----- Restore handling -----

    // Old style: directly match the stored vs on device signature blocks
    static boolean signaturesMatch(Signature[] storedSigs, PackageInfo target) {
        if (target == null) {
            return false;
        }

        // If the target resides on the system partition, we allow it to restore
        // data from the like-named package in a restore set even if the signatures
        // do not match.  (Unlike general applications, those flashed to the system
        // partition will be signed with the device's platform certificate, so on
        // different phones the same system app will have different signatures.)
        if ((target.applicationInfo.flags & ApplicationInfo.FLAG_SYSTEM) != 0) {
            if (MORE_DEBUG) Slog.v(TAG, "System app " + target.packageName + " - skipping sig check");
            return true;
        }

        // Allow unsigned apps, but not signed on one device and unsigned on the other
        // !!! TODO: is this the right policy?
        Signature[] deviceSigs = target.signatures;
        if (MORE_DEBUG) Slog.v(TAG, "signaturesMatch(): stored=" + storedSigs
                + " device=" + deviceSigs);
        if ((storedSigs == null || storedSigs.length == 0)
                && (deviceSigs == null || deviceSigs.length == 0)) {
            return true;
        }
        if (storedSigs == null || deviceSigs == null) {
            return false;
        }

        // !!! TODO: this demands that every stored signature match one
        // that is present on device, and does not demand the converse.
        // Is this this right policy?
        int nStored = storedSigs.length;
        int nDevice = deviceSigs.length;

        for (int i=0; i < nStored; i++) {
            boolean match = false;
            for (int j=0; j < nDevice; j++) {
                if (storedSigs[i].equals(deviceSigs[j])) {
                    match = true;
                    break;
                }
            }
            if (!match) {
                return false;
            }
        }
        return true;
    }

    // Used by both incremental and full restore
    void restoreWidgetData(String packageName, byte[] widgetData) {
        // Apply the restored widget state and generate the ID update for the app
        // TODO: http://b/22388012
        if (MORE_DEBUG) {
            Slog.i(TAG, "Incorporating restored widget data");
        }
        AppWidgetBackupBridge.restoreWidgetState(packageName, widgetData, UserHandle.USER_SYSTEM);
    }

    // *****************************
    // NEW UNIFIED RESTORE IMPLEMENTATION
    // *****************************

    // states of the unified-restore state machine
    enum UnifiedRestoreState {
        INITIAL,
        RUNNING_QUEUE,
        RESTORE_KEYVALUE,
        RESTORE_FULL,
        RESTORE_FINISHED,
        FINAL
    }

    class PerformUnifiedRestoreTask implements BackupRestoreTask {
        // Transport we're working with to do the restore
        private IBackupTransport mTransport;

        // Where per-transport saved state goes
        File mStateDir;

        // Restore observer; may be null
        private IRestoreObserver mObserver;

        // BackuoManagerMonitor; may be null
        private IBackupManagerMonitor mMonitor;

        // Token identifying the dataset to the transport
        private long mToken;

        // When this is a restore-during-install, this is the token identifying the
        // operation to the Package Manager, and we must ensure that we let it know
        // when we're finished.
        private int mPmToken;

        // When this is restore-during-install, we need to tell the package manager
        // whether we actually launched the app, because this affects notifications
        // around externally-visible state transitions.
        private boolean mDidLaunch;

        // Is this a whole-system restore, i.e. are we establishing a new ancestral
        // dataset to base future restore-at-install operations from?
        private boolean mIsSystemRestore;

        // If this is a single-package restore, what package are we interested in?
        private PackageInfo mTargetPackage;

        // In all cases, the calculated list of packages that we are trying to restore
        private List<PackageInfo> mAcceptSet;

        // Our bookkeeping about the ancestral dataset
        private PackageManagerBackupAgent mPmAgent;

        // Currently-bound backup agent for restore + restoreFinished purposes
        private IBackupAgent mAgent;

        // What sort of restore we're doing now
        private RestoreDescription mRestoreDescription;

        // The package we're currently restoring
        private PackageInfo mCurrentPackage;

        // Widget-related data handled as part of this restore operation
        private byte[] mWidgetData;

        // Number of apps restored in this pass
        private int mCount;

        // When did we start?
        private long mStartRealtime;

        // State machine progress
        private UnifiedRestoreState mState;

        // How are things going?
        private int mStatus;

        // Done?
        private boolean mFinished;

        // Key/value: bookkeeping about staged data and files for agent access
        private File mBackupDataName;
        private File mStageName;
        private File mSavedStateName;
        private File mNewStateName;
        ParcelFileDescriptor mBackupData;
        ParcelFileDescriptor mNewState;

        private final int mEphemeralOpToken;

        // Invariant: mWakelock is already held, and this task is responsible for
        // releasing it at the end of the restore operation.
        PerformUnifiedRestoreTask(IBackupTransport transport, IRestoreObserver observer,
                IBackupManagerMonitor monitor, long restoreSetToken, PackageInfo targetPackage,
                int pmToken, boolean isFullSystemRestore, String[] filterSet) {
            mEphemeralOpToken = generateRandomIntegerToken();
            mState = UnifiedRestoreState.INITIAL;
            mStartRealtime = SystemClock.elapsedRealtime();

            mTransport = transport;
            mObserver = observer;
            mMonitor = monitor;
            mToken = restoreSetToken;
            mPmToken = pmToken;
            mTargetPackage = targetPackage;
            mIsSystemRestore = isFullSystemRestore;
            mFinished = false;
            mDidLaunch = false;

            if (targetPackage != null) {
                // Single package restore
                mAcceptSet = new ArrayList<PackageInfo>();
                mAcceptSet.add(targetPackage);
            } else {
                // Everything possible, or a target set
                if (filterSet == null) {
                    // We want everything and a pony
                    List<PackageInfo> apps =
                            PackageManagerBackupAgent.getStorableApplications(mPackageManager);
                    filterSet = packagesToNames(apps);
                    if (DEBUG) {
                        Slog.i(TAG, "Full restore; asking about " + filterSet.length + " apps");
                    }
                }

                mAcceptSet = new ArrayList<PackageInfo>(filterSet.length);

                // Pro tem, we insist on moving the settings provider package to last place.
                // Keep track of whether it's in the list, and bump it down if so.  We also
                // want to do the system package itself first if it's called for.
                boolean hasSystem = false;
                boolean hasSettings = false;
                for (int i = 0; i < filterSet.length; i++) {
                    try {
                        PackageInfo info = mPackageManager.getPackageInfo(filterSet[i], 0);
                        if ("android".equals(info.packageName)) {
                            hasSystem = true;
                            continue;
                        }
                        if (SETTINGS_PACKAGE.equals(info.packageName)) {
                            hasSettings = true;
                            continue;
                        }

                        if (appIsEligibleForBackup(info.applicationInfo, mPackageManager)) {
                            mAcceptSet.add(info);
                        }
                    } catch (NameNotFoundException e) {
                        // requested package name doesn't exist; ignore it
                    }
                }
                if (hasSystem) {
                    try {
                        mAcceptSet.add(0, mPackageManager.getPackageInfo("android", 0));
                    } catch (NameNotFoundException e) {
                        // won't happen; we know a priori that it's valid
                    }
                }
                if (hasSettings) {
                    try {
                        mAcceptSet.add(mPackageManager.getPackageInfo(SETTINGS_PACKAGE, 0));
                    } catch (NameNotFoundException e) {
                        // this one is always valid too
                    }
                }
            }

            if (MORE_DEBUG) {
                Slog.v(TAG, "Restore; accept set size is " + mAcceptSet.size());
                for (PackageInfo info : mAcceptSet) {
                    Slog.v(TAG, "   " + info.packageName);
                }
            }
        }

        private String[] packagesToNames(List<PackageInfo> apps) {
            final int N = apps.size();
            String[] names = new String[N];
            for (int i = 0; i < N; i++) {
                names[i] = apps.get(i).packageName;
            }
            return names;
        }

        // Execute one tick of whatever state machine the task implements
        @Override
        public void execute() {
            if (MORE_DEBUG) Slog.v(TAG, "*** Executing restore step " + mState);
            switch (mState) {
                case INITIAL:
                    startRestore();
                    break;

                case RUNNING_QUEUE:
                    dispatchNextRestore();
                    break;

                case RESTORE_KEYVALUE:
                    restoreKeyValue();
                    break;

                case RESTORE_FULL:
                    restoreFull();
                    break;

                case RESTORE_FINISHED:
                    restoreFinished();
                    break;

                case FINAL:
                    if (!mFinished) finalizeRestore();
                    else {
                        Slog.e(TAG, "Duplicate finish");
                    }
                    mFinished = true;
                    break;
            }
        }

        /*
         * SKETCH OF OPERATION
         *
         * create one of these PerformUnifiedRestoreTask objects, telling it which
         * dataset & transport to address, and then parameters within the restore
         * operation: single target package vs many, etc.
         *
         * 1. transport.startRestore(token, list-of-packages).  If we need @pm@  it is
         * always placed first and the settings provider always placed last [for now].
         *
         * 1a [if we needed @pm@ then nextRestorePackage() and restore the PMBA inline]
         *
         *   [ state change => RUNNING_QUEUE ]
         *
         * NOW ITERATE:
         *
         * { 3. t.nextRestorePackage()
         *   4. does the metadata for this package allow us to restore it?
         *      does the on-disk app permit us to restore it? [re-check allowBackup etc]
         *   5. is this a key/value dataset?  => key/value agent restore
         *       [ state change => RESTORE_KEYVALUE ]
         *       5a. spin up agent
         *       5b. t.getRestoreData() to stage it properly
         *       5c. call into agent to perform restore
         *       5d. tear down agent
         *       [ state change => RUNNING_QUEUE ]
         *
         *   6. else it's a stream dataset:
         *       [ state change => RESTORE_FULL ]
         *       6a. instantiate the engine for a stream restore: engine handles agent lifecycles
         *       6b. spin off engine runner on separate thread
         *       6c. ITERATE getNextFullRestoreDataChunk() and copy data to engine runner socket
         *       [ state change => RUNNING_QUEUE ]
         * }
         *
         *   [ state change => FINAL ]
         *
         * 7. t.finishRestore(), release wakelock, etc.
         *
         *
         */

        // state INITIAL : set up for the restore and read the metadata if necessary
        private  void startRestore() {
            sendStartRestore(mAcceptSet.size());

            // If we're starting a full-system restore, set up to begin widget ID remapping
            if (mIsSystemRestore) {
                // TODO: http://b/22388012
                AppWidgetBackupBridge.restoreStarting(UserHandle.USER_SYSTEM);
            }

            try {
                String transportDir = mTransport.transportDirName();
                mStateDir = new File(mBaseStateDir, transportDir);

                // Fetch the current metadata from the dataset first
                PackageInfo pmPackage = new PackageInfo();
                pmPackage.packageName = PACKAGE_MANAGER_SENTINEL;
                mAcceptSet.add(0, pmPackage);

                PackageInfo[] packages = mAcceptSet.toArray(new PackageInfo[0]);
                mStatus = mTransport.startRestore(mToken, packages);
                if (mStatus != BackupTransport.TRANSPORT_OK) {
                    Slog.e(TAG, "Transport error " + mStatus + "; no restore possible");
                    mStatus = BackupTransport.TRANSPORT_ERROR;
                    executeNextState(UnifiedRestoreState.FINAL);
                    return;
                }

                RestoreDescription desc = mTransport.nextRestorePackage();
                if (desc == null) {
                    Slog.e(TAG, "No restore metadata available; halting");
                    mMonitor = monitorEvent(mMonitor,
                            BackupManagerMonitor.LOG_EVENT_ID_NO_RESTORE_METADATA_AVAILABLE,
                            mCurrentPackage,
                            BackupManagerMonitor.LOG_EVENT_CATEGORY_BACKUP_MANAGER_POLICY, null);
                    mStatus = BackupTransport.TRANSPORT_ERROR;
                    executeNextState(UnifiedRestoreState.FINAL);
                    return;
                }
                if (!PACKAGE_MANAGER_SENTINEL.equals(desc.getPackageName())) {
                    Slog.e(TAG, "Required package metadata but got "
                            + desc.getPackageName());
                    mMonitor = monitorEvent(mMonitor,
                            BackupManagerMonitor.LOG_EVENT_ID_NO_PM_METADATA_RECEIVED,
                            mCurrentPackage,
                            BackupManagerMonitor.LOG_EVENT_CATEGORY_BACKUP_MANAGER_POLICY, null);
                    mStatus = BackupTransport.TRANSPORT_ERROR;
                    executeNextState(UnifiedRestoreState.FINAL);
                    return;
                }

                // Pull the Package Manager metadata from the restore set first
                mCurrentPackage = new PackageInfo();
                mCurrentPackage.packageName = PACKAGE_MANAGER_SENTINEL;
                mPmAgent = makeMetadataAgent(null);
                mAgent = IBackupAgent.Stub.asInterface(mPmAgent.onBind());
                if (MORE_DEBUG) {
                    Slog.v(TAG, "initiating restore for PMBA");
                }
                initiateOneRestore(mCurrentPackage, 0);
                // The PM agent called operationComplete() already, because our invocation
                // of it is process-local and therefore synchronous.  That means that the
                // next-state message (RUNNING_QUEUE) is already enqueued.  Only if we're
                // unable to proceed with running the queue do we remove that pending
                // message and jump straight to the FINAL state.  Because this was
                // synchronous we also know that we should cancel the pending timeout
                // message.
                mBackupHandler.removeMessages(MSG_RESTORE_OPERATION_TIMEOUT);

                // Verify that the backup set includes metadata.  If not, we can't do
                // signature/version verification etc, so we simply do not proceed with
                // the restore operation.
                if (!mPmAgent.hasMetadata()) {
                    Slog.e(TAG, "PM agent has no metadata, so not restoring");
                    mMonitor = monitorEvent(mMonitor,
                            BackupManagerMonitor.LOG_EVENT_ID_PM_AGENT_HAS_NO_METADATA,
                            mCurrentPackage,
                            BackupManagerMonitor.LOG_EVENT_CATEGORY_BACKUP_MANAGER_POLICY, null);
                    EventLog.writeEvent(EventLogTags.RESTORE_AGENT_FAILURE,
                            PACKAGE_MANAGER_SENTINEL,
                            "Package manager restore metadata missing");
                    mStatus = BackupTransport.TRANSPORT_ERROR;
                    mBackupHandler.removeMessages(MSG_BACKUP_RESTORE_STEP, this);
                    executeNextState(UnifiedRestoreState.FINAL);
                    return;
                }

                // Success; cache the metadata and continue as expected with the
                // next state already enqueued

            } catch (Exception e) {
                // If we lost the transport at any time, halt
                Slog.e(TAG, "Unable to contact transport for restore: " + e.getMessage());
                mMonitor = monitorEvent(mMonitor,
                        BackupManagerMonitor.LOG_EVENT_ID_LOST_TRANSPORT,
                        null,
                        BackupManagerMonitor.LOG_EVENT_CATEGORY_TRANSPORT, null);
                mStatus = BackupTransport.TRANSPORT_ERROR;
                mBackupHandler.removeMessages(MSG_BACKUP_RESTORE_STEP, this);
                executeNextState(UnifiedRestoreState.FINAL);
                return;
            }
        }

        // state RUNNING_QUEUE : figure out what the next thing to be restored is,
        // and fire the appropriate next step
        private void dispatchNextRestore() {
            UnifiedRestoreState nextState = UnifiedRestoreState.FINAL;
            try {
                mRestoreDescription = mTransport.nextRestorePackage();
                final String pkgName = (mRestoreDescription != null)
                        ? mRestoreDescription.getPackageName() : null;
                if (pkgName == null) {
                    Slog.e(TAG, "Failure getting next package name");
                    EventLog.writeEvent(EventLogTags.RESTORE_TRANSPORT_FAILURE);
                    nextState = UnifiedRestoreState.FINAL;
                    return;
                } else if (mRestoreDescription == RestoreDescription.NO_MORE_PACKAGES) {
                    // Yay we've reached the end cleanly
                    if (DEBUG) {
                        Slog.v(TAG, "No more packages; finishing restore");
                    }
                    int millis = (int) (SystemClock.elapsedRealtime() - mStartRealtime);
                    EventLog.writeEvent(EventLogTags.RESTORE_SUCCESS, mCount, millis);
                    nextState = UnifiedRestoreState.FINAL;
                    return;
                }

                if (DEBUG) {
                    Slog.i(TAG, "Next restore package: " + mRestoreDescription);
                }
                sendOnRestorePackage(pkgName);

                Metadata metaInfo = mPmAgent.getRestoredMetadata(pkgName);
                if (metaInfo == null) {
                    Slog.e(TAG, "No metadata for " + pkgName);
                    EventLog.writeEvent(EventLogTags.RESTORE_AGENT_FAILURE, pkgName,
                            "Package metadata missing");
                    nextState = UnifiedRestoreState.RUNNING_QUEUE;
                    return;
                }

                try {
                    mCurrentPackage = mPackageManager.getPackageInfo(
                            pkgName, PackageManager.GET_SIGNATURES);
                } catch (NameNotFoundException e) {
                    // Whoops, we thought we could restore this package but it
                    // turns out not to be present.  Skip it.
                    Slog.e(TAG, "Package not present: " + pkgName);
                    mMonitor = monitorEvent(mMonitor,
                            BackupManagerMonitor.LOG_EVENT_ID_PACKAGE_NOT_PRESENT,
                            mCurrentPackage,
                            BackupManagerMonitor.LOG_EVENT_CATEGORY_BACKUP_MANAGER_POLICY,
                            null);
                    EventLog.writeEvent(EventLogTags.RESTORE_AGENT_FAILURE, pkgName,
                            "Package missing on device");
                    nextState = UnifiedRestoreState.RUNNING_QUEUE;
                    return;
                }

                if (metaInfo.versionCode > mCurrentPackage.versionCode) {
                    // Data is from a "newer" version of the app than we have currently
                    // installed.  If the app has not declared that it is prepared to
                    // handle this case, we do not attempt the restore.
                    if ((mCurrentPackage.applicationInfo.flags
                            & ApplicationInfo.FLAG_RESTORE_ANY_VERSION) == 0) {
                        String message = "Source version " + metaInfo.versionCode
                                + " > installed version " + mCurrentPackage.versionCode;
                        Slog.w(TAG, "Package " + pkgName + ": " + message);
                        Bundle monitoringExtras = putMonitoringExtra(null,
                                BackupManagerMonitor.EXTRA_LOG_RESTORE_VERSION,
                                metaInfo.versionCode);
                        monitoringExtras = putMonitoringExtra(monitoringExtras,
                                BackupManagerMonitor.EXTRA_LOG_RESTORE_ANYWAY, false);
                        mMonitor = monitorEvent(mMonitor,
                                BackupManagerMonitor.LOG_EVENT_ID_RESTORE_VERSION_HIGHER,
                                mCurrentPackage,
                                BackupManagerMonitor.LOG_EVENT_CATEGORY_BACKUP_MANAGER_POLICY,
                                monitoringExtras);
                        EventLog.writeEvent(EventLogTags.RESTORE_AGENT_FAILURE,
                                pkgName, message);
                        nextState = UnifiedRestoreState.RUNNING_QUEUE;
                        return;
                    } else {
                        if (DEBUG) Slog.v(TAG, "Source version " + metaInfo.versionCode
                                + " > installed version " + mCurrentPackage.versionCode
                                + " but restoreAnyVersion");
                        Bundle monitoringExtras = putMonitoringExtra(null,
                                BackupManagerMonitor.EXTRA_LOG_RESTORE_VERSION,
                                metaInfo.versionCode);
                        monitoringExtras = putMonitoringExtra(monitoringExtras,
                                BackupManagerMonitor.EXTRA_LOG_RESTORE_ANYWAY, true);
                        mMonitor = monitorEvent(mMonitor,
                                BackupManagerMonitor.LOG_EVENT_ID_RESTORE_VERSION_HIGHER,
                                mCurrentPackage,
                                BackupManagerMonitor.LOG_EVENT_CATEGORY_BACKUP_MANAGER_POLICY,
                                monitoringExtras);
                    }
                }

                if (MORE_DEBUG) Slog.v(TAG, "Package " + pkgName
                        + " restore version [" + metaInfo.versionCode
                        + "] is compatible with installed version ["
                        + mCurrentPackage.versionCode + "]");

                // Reset per-package preconditions and fire the appropriate next state
                mWidgetData = null;
                final int type = mRestoreDescription.getDataType();
                if (type == RestoreDescription.TYPE_KEY_VALUE) {
                    nextState = UnifiedRestoreState.RESTORE_KEYVALUE;
                } else if (type == RestoreDescription.TYPE_FULL_STREAM) {
                    nextState = UnifiedRestoreState.RESTORE_FULL;
                } else {
                    // Unknown restore type; ignore this package and move on
                    Slog.e(TAG, "Unrecognized restore type " + type);
                    nextState = UnifiedRestoreState.RUNNING_QUEUE;
                    return;
                }
            } catch (Exception e) {
                Slog.e(TAG, "Can't get next restore target from transport; halting: "
                        + e.getMessage());
                EventLog.writeEvent(EventLogTags.RESTORE_TRANSPORT_FAILURE);
                nextState = UnifiedRestoreState.FINAL;
                return;
            } finally {
                executeNextState(nextState);
            }
        }

        // state RESTORE_KEYVALUE : restore one package via key/value API set
        private void restoreKeyValue() {
            // Initiating the restore will pass responsibility for the state machine's
            // progress to the agent callback, so we do not always execute the
            // next state here.
            final String packageName = mCurrentPackage.packageName;
            // Validate some semantic requirements that apply in this way
            // only to the key/value restore API flow
            if (mCurrentPackage.applicationInfo.backupAgentName == null
                    || "".equals(mCurrentPackage.applicationInfo.backupAgentName)) {
                if (MORE_DEBUG) {
                    Slog.i(TAG, "Data exists for package " + packageName
                            + " but app has no agent; skipping");
                }
                mMonitor = monitorEvent(mMonitor,
                        BackupManagerMonitor.LOG_EVENT_ID_APP_HAS_NO_AGENT, mCurrentPackage,
                        BackupManagerMonitor.LOG_EVENT_CATEGORY_AGENT, null);
                EventLog.writeEvent(EventLogTags.RESTORE_AGENT_FAILURE, packageName,
                        "Package has no agent");
                executeNextState(UnifiedRestoreState.RUNNING_QUEUE);
                return;
            }

            Metadata metaInfo = mPmAgent.getRestoredMetadata(packageName);
            if (!BackupUtils.signaturesMatch(metaInfo.sigHashes, mCurrentPackage)) {
                Slog.w(TAG, "Signature mismatch restoring " + packageName);
                mMonitor = monitorEvent(mMonitor,
                        BackupManagerMonitor.LOG_EVENT_ID_SIGNATURE_MISMATCH, mCurrentPackage,
                        BackupManagerMonitor.LOG_EVENT_CATEGORY_BACKUP_MANAGER_POLICY, null);
                EventLog.writeEvent(EventLogTags.RESTORE_AGENT_FAILURE, packageName,
                        "Signature mismatch");
                executeNextState(UnifiedRestoreState.RUNNING_QUEUE);
                return;
            }

            // Good to go!  Set up and bind the agent...
            mAgent = bindToAgentSynchronous(
                    mCurrentPackage.applicationInfo,
                    ApplicationThreadConstants.BACKUP_MODE_INCREMENTAL);
            if (mAgent == null) {
                Slog.w(TAG, "Can't find backup agent for " + packageName);
                mMonitor = monitorEvent(mMonitor,
                        BackupManagerMonitor.LOG_EVENT_ID_CANT_FIND_AGENT, mCurrentPackage,
                        BackupManagerMonitor.LOG_EVENT_CATEGORY_BACKUP_MANAGER_POLICY, null);
                EventLog.writeEvent(EventLogTags.RESTORE_AGENT_FAILURE, packageName,
                        "Restore agent missing");
                executeNextState(UnifiedRestoreState.RUNNING_QUEUE);
                return;
            }

            // Whatever happens next, we've launched the target app now; remember that.
            mDidLaunch = true;

            // And then finally start the restore on this agent
            try {
                initiateOneRestore(mCurrentPackage, metaInfo.versionCode);
                ++mCount;
            } catch (Exception e) {
                Slog.e(TAG, "Error when attempting restore: " + e.toString());
                keyValueAgentErrorCleanup();
                executeNextState(UnifiedRestoreState.RUNNING_QUEUE);
            }
        }

        // Guts of a key/value restore operation
        void initiateOneRestore(PackageInfo app, int appVersionCode) {
            final String packageName = app.packageName;

            if (DEBUG) Slog.d(TAG, "initiateOneRestore packageName=" + packageName);

            // !!! TODO: get the dirs from the transport
            mBackupDataName = new File(mDataDir, packageName + ".restore");
            mStageName = new File(mDataDir, packageName + ".stage");
            mNewStateName = new File(mStateDir, packageName + ".new");
            mSavedStateName = new File(mStateDir, packageName);

            // don't stage the 'android' package where the wallpaper data lives.  this is
            // an optimization: we know there's no widget data hosted/published by that
            // package, and this way we avoid doing a spurious copy of MB-sized wallpaper
            // data following the download.
            boolean staging = !packageName.equals("android");
            ParcelFileDescriptor stage;
            File downloadFile = (staging) ? mStageName : mBackupDataName;

            try {
                // Run the transport's restore pass
                stage = ParcelFileDescriptor.open(downloadFile,
                        ParcelFileDescriptor.MODE_READ_WRITE |
                        ParcelFileDescriptor.MODE_CREATE |
                        ParcelFileDescriptor.MODE_TRUNCATE);

                if (mTransport.getRestoreData(stage) != BackupTransport.TRANSPORT_OK) {
                    // Transport-level failure, so we wind everything up and
                    // terminate the restore operation.
                    Slog.e(TAG, "Error getting restore data for " + packageName);
                    EventLog.writeEvent(EventLogTags.RESTORE_TRANSPORT_FAILURE);
                    stage.close();
                    downloadFile.delete();
                    executeNextState(UnifiedRestoreState.FINAL);
                    return;
                }

                // We have the data from the transport. Now we extract and strip
                // any per-package metadata (typically widget-related information)
                // if appropriate
                if (staging) {
                    stage.close();
                    stage = ParcelFileDescriptor.open(downloadFile,
                            ParcelFileDescriptor.MODE_READ_ONLY);

                    mBackupData = ParcelFileDescriptor.open(mBackupDataName,
                            ParcelFileDescriptor.MODE_READ_WRITE |
                            ParcelFileDescriptor.MODE_CREATE |
                            ParcelFileDescriptor.MODE_TRUNCATE);

                    BackupDataInput in = new BackupDataInput(stage.getFileDescriptor());
                    BackupDataOutput out = new BackupDataOutput(mBackupData.getFileDescriptor());
                    byte[] buffer = new byte[8192]; // will grow when needed
                    while (in.readNextHeader()) {
                        final String key = in.getKey();
                        final int size = in.getDataSize();

                        // is this a special key?
                        if (key.equals(KEY_WIDGET_STATE)) {
                            if (DEBUG) {
                                Slog.i(TAG, "Restoring widget state for " + packageName);
                            }
                            mWidgetData = new byte[size];
                            in.readEntityData(mWidgetData, 0, size);
                        } else {
                            if (size > buffer.length) {
                                buffer = new byte[size];
                            }
                            in.readEntityData(buffer, 0, size);
                            out.writeEntityHeader(key, size);
                            out.writeEntityData(buffer, size);
                        }
                    }

                    mBackupData.close();
                }

                // Okay, we have the data.  Now have the agent do the restore.
                stage.close();

                mBackupData = ParcelFileDescriptor.open(mBackupDataName,
                        ParcelFileDescriptor.MODE_READ_ONLY);

                mNewState = ParcelFileDescriptor.open(mNewStateName,
                        ParcelFileDescriptor.MODE_READ_WRITE |
                        ParcelFileDescriptor.MODE_CREATE |
                        ParcelFileDescriptor.MODE_TRUNCATE);

                // Kick off the restore, checking for hung agents.  The timeout or
                // the operationComplete() callback will schedule the next step,
                // so we do not do that here.
                prepareOperationTimeout(mEphemeralOpToken, TIMEOUT_RESTORE_INTERVAL,
                        this, OP_TYPE_RESTORE_WAIT);
                mAgent.doRestore(mBackupData, appVersionCode, mNewState,
                        mEphemeralOpToken, mBackupManagerBinder);
            } catch (Exception e) {
                Slog.e(TAG, "Unable to call app for restore: " + packageName, e);
                EventLog.writeEvent(EventLogTags.RESTORE_AGENT_FAILURE,
                        packageName, e.toString());
                keyValueAgentErrorCleanup();    // clears any pending timeout messages as well

                // After a restore failure we go back to running the queue.  If there
                // are no more packages to be restored that will be handled by the
                // next step.
                executeNextState(UnifiedRestoreState.RUNNING_QUEUE);
            }
        }

        // state RESTORE_FULL : restore one package via streaming engine
        private void restoreFull() {
            // None of this can run on the work looper here, so we spin asynchronous
            // work like this:
            //
            //   StreamFeederThread: read data from mTransport.getNextFullRestoreDataChunk()
            //                       write it into the pipe to the engine
            //   EngineThread: FullRestoreEngine thread communicating with the target app
            //
            // When finished, StreamFeederThread executes next state as appropriate on the
            // backup looper, and the overall unified restore task resumes
            try {
                StreamFeederThread feeder = new StreamFeederThread();
                if (MORE_DEBUG) {
                    Slog.i(TAG, "Spinning threads for stream restore of "
                            + mCurrentPackage.packageName);
                }
                new Thread(feeder, "unified-stream-feeder").start();

                // At this point the feeder is responsible for advancing the restore
                // state, so we're done here.
            } catch (IOException e) {
                // Unable to instantiate the feeder thread -- we need to bail on the
                // current target.  We haven't asked the transport for data yet, though,
                // so we can do that simply by going back to running the restore queue.
                Slog.e(TAG, "Unable to construct pipes for stream restore!");
                executeNextState(UnifiedRestoreState.RUNNING_QUEUE);
            }
        }

        // state RESTORE_FINISHED : provide the "no more data" signpost callback at the end
        private void restoreFinished() {
            if (DEBUG) {
                Slog.d(TAG, "restoreFinished packageName=" + mCurrentPackage.packageName);
            }
            try {
                prepareOperationTimeout(mEphemeralOpToken, TIMEOUT_RESTORE_FINISHED_INTERVAL, this,
                        OP_TYPE_RESTORE_WAIT);
                mAgent.doRestoreFinished(mEphemeralOpToken, mBackupManagerBinder);
                // If we get this far, the callback or timeout will schedule the
                // next restore state, so we're done
            } catch (Exception e) {
                final String packageName = mCurrentPackage.packageName;
                Slog.e(TAG, "Unable to finalize restore of " + packageName);
                EventLog.writeEvent(EventLogTags.RESTORE_AGENT_FAILURE,
                        packageName, e.toString());
                keyValueAgentErrorCleanup();
                executeNextState(UnifiedRestoreState.RUNNING_QUEUE);
            }
        }

        class StreamFeederThread extends RestoreEngine implements Runnable, BackupRestoreTask {
            final String TAG = "StreamFeederThread";
            FullRestoreEngine mEngine;
            EngineThread mEngineThread;

            // pipe through which we read data from the transport. [0] read, [1] write
            ParcelFileDescriptor[] mTransportPipes;

            // pipe through which the engine will read data.  [0] read, [1] write
            ParcelFileDescriptor[] mEnginePipes;

            private final int mEphemeralOpToken;

            public StreamFeederThread() throws IOException {
                mEphemeralOpToken = generateRandomIntegerToken();
                mTransportPipes = ParcelFileDescriptor.createPipe();
                mEnginePipes = ParcelFileDescriptor.createPipe();
                setRunning(true);
            }

            @Override
            public void run() {
                UnifiedRestoreState nextState = UnifiedRestoreState.RUNNING_QUEUE;
                int status = BackupTransport.TRANSPORT_OK;

                EventLog.writeEvent(EventLogTags.FULL_RESTORE_PACKAGE,
                        mCurrentPackage.packageName);

                mEngine = new FullRestoreEngine(this, null, mMonitor, mCurrentPackage, false, false, mEphemeralOpToken);
                mEngineThread = new EngineThread(mEngine, mEnginePipes[0]);

                ParcelFileDescriptor eWriteEnd = mEnginePipes[1];
                ParcelFileDescriptor tReadEnd = mTransportPipes[0];
                ParcelFileDescriptor tWriteEnd = mTransportPipes[1];

                int bufferSize = 32 * 1024;
                byte[] buffer = new byte[bufferSize];
                FileOutputStream engineOut = new FileOutputStream(eWriteEnd.getFileDescriptor());
                FileInputStream transportIn = new FileInputStream(tReadEnd.getFileDescriptor());

                // spin up the engine and start moving data to it
                new Thread(mEngineThread, "unified-restore-engine").start();

                try {
                    while (status == BackupTransport.TRANSPORT_OK) {
                        // have the transport write some of the restoring data to us
                        int result = mTransport.getNextFullRestoreDataChunk(tWriteEnd);
                        if (result > 0) {
                            // The transport wrote this many bytes of restore data to the
                            // pipe, so pass it along to the engine.
                            if (MORE_DEBUG) {
                                Slog.v(TAG, "  <- transport provided chunk size " + result);
                            }
                            if (result > bufferSize) {
                                bufferSize = result;
                                buffer = new byte[bufferSize];
                            }
                            int toCopy = result;
                            while (toCopy > 0) {
                                int n = transportIn.read(buffer, 0, toCopy);
                                engineOut.write(buffer, 0, n);
                                toCopy -= n;
                                if (MORE_DEBUG) {
                                    Slog.v(TAG, "  -> wrote " + n + " to engine, left=" + toCopy);
                                }
                            }
                        } else if (result == BackupTransport.NO_MORE_DATA) {
                            // Clean finish.  Wind up and we're done!
                            if (MORE_DEBUG) {
                                Slog.i(TAG, "Got clean full-restore EOF for "
                                        + mCurrentPackage.packageName);
                            }
                            status = BackupTransport.TRANSPORT_OK;
                            break;
                        } else {
                            // Transport reported some sort of failure; the fall-through
                            // handling will deal properly with that.
                            Slog.e(TAG, "Error " + result + " streaming restore for "
                                    + mCurrentPackage.packageName);
                            EventLog.writeEvent(EventLogTags.RESTORE_TRANSPORT_FAILURE);
                            status = result;
                        }
                    }
                    if (MORE_DEBUG) Slog.v(TAG, "Done copying to engine, falling through");
                } catch (IOException e) {
                    // We lost our ability to communicate via the pipes.  That's worrying
                    // but potentially recoverable; abandon this package's restore but
                    // carry on with the next restore target.
                    Slog.e(TAG, "Unable to route data for restore");
                    EventLog.writeEvent(EventLogTags.RESTORE_AGENT_FAILURE,
                            mCurrentPackage.packageName, "I/O error on pipes");
                    status = BackupTransport.AGENT_ERROR;
                } catch (Exception e) {
                    // The transport threw; terminate the whole operation.  Closing
                    // the sockets will wake up the engine and it will then tidy up the
                    // remote end.
                    Slog.e(TAG, "Transport failed during restore: " + e.getMessage());
                    EventLog.writeEvent(EventLogTags.RESTORE_TRANSPORT_FAILURE);
                    status = BackupTransport.TRANSPORT_ERROR;
                } finally {
                    // Close the transport pipes and *our* end of the engine pipe,
                    // but leave the engine thread's end open so that it properly
                    // hits EOF and winds up its operations.
                    IoUtils.closeQuietly(mEnginePipes[1]);
                    IoUtils.closeQuietly(mTransportPipes[0]);
                    IoUtils.closeQuietly(mTransportPipes[1]);

                    // Don't proceed until the engine has wound up operations
                    mEngineThread.waitForResult();

                    // Now we're really done with this one too
                    IoUtils.closeQuietly(mEnginePipes[0]);

                    // In all cases we want to remember whether we launched
                    // the target app as part of our work so far.
                    mDidLaunch = (mEngine.getAgent() != null);

                    // If we hit a transport-level error, we are done with everything;
                    // if we hit an agent error we just go back to running the queue.
                    if (status == BackupTransport.TRANSPORT_OK) {
                        // Clean finish means we issue the restore-finished callback
                        nextState = UnifiedRestoreState.RESTORE_FINISHED;

                        // the engine bound the target's agent, so recover that binding
                        // to use for the callback.
                        mAgent = mEngine.getAgent();

                        // and the restored widget data, if any
                        mWidgetData = mEngine.getWidgetData();
                    } else {
                        // Something went wrong somewhere.  Whether it was at the transport
                        // level is immaterial; we need to tell the transport to bail
                        try {
                            mTransport.abortFullRestore();
                        } catch (Exception e) {
                            // transport itself is dead; make sure we handle this as a
                            // fatal error
                            Slog.e(TAG, "Transport threw from abortFullRestore: " + e.getMessage());
                            status = BackupTransport.TRANSPORT_ERROR;
                        }

                        // We also need to wipe the current target's data, as it's probably
                        // in an incoherent state.
                        clearApplicationDataSynchronous(mCurrentPackage.packageName);

                        // Schedule the next state based on the nature of our failure
                        if (status == BackupTransport.TRANSPORT_ERROR) {
                            nextState = UnifiedRestoreState.FINAL;
                        } else {
                            nextState = UnifiedRestoreState.RUNNING_QUEUE;
                        }
                    }
                    executeNextState(nextState);
                    setRunning(false);
                }
            }

            // BackupRestoreTask interface, specifically for timeout handling

            @Override
            public void execute() { /* intentionally empty */ }

            @Override
            public void operationComplete(long result) { /* intentionally empty */ }

            // The app has timed out handling a restoring file
            @Override
            public void handleCancel(boolean cancelAll) {
                removeOperation(mEphemeralOpToken);
                if (DEBUG) {
                    Slog.w(TAG, "Full-data restore target timed out; shutting down");
                }

                mMonitor = monitorEvent(mMonitor,
                        BackupManagerMonitor.LOG_EVENT_ID_FULL_RESTORE_TIMEOUT,
                        mCurrentPackage, BackupManagerMonitor.LOG_EVENT_CATEGORY_AGENT, null);
                mEngineThread.handleTimeout();

                IoUtils.closeQuietly(mEnginePipes[1]);
                mEnginePipes[1] = null;
                IoUtils.closeQuietly(mEnginePipes[0]);
                mEnginePipes[0] = null;
            }
        }

        class EngineThread implements Runnable {
            FullRestoreEngine mEngine;
            FileInputStream mEngineStream;

            EngineThread(FullRestoreEngine engine, ParcelFileDescriptor engineSocket) {
                mEngine = engine;
                engine.setRunning(true);
                // We *do* want this FileInputStream to own the underlying fd, so that
                // when we are finished with it, it closes this end of the pipe in a way
                // that signals its other end.
                mEngineStream = new FileInputStream(engineSocket.getFileDescriptor(), true);
            }

            public boolean isRunning() {
                return mEngine.isRunning();
            }

            public int waitForResult() {
                return mEngine.waitForResult();
            }

            @Override
            public void run() {
                try {
                    while (mEngine.isRunning()) {
                        // Tell it to be sure to leave the agent instance up after finishing
                        mEngine.restoreOneFile(mEngineStream, false);
                    }
                } finally {
                    // Because mEngineStream adopted its underlying FD, this also
                    // closes this end of the pipe.
                    IoUtils.closeQuietly(mEngineStream);
                }
            }

            public void handleTimeout() {
                IoUtils.closeQuietly(mEngineStream);
                mEngine.handleTimeout();
            }
        }

        // state FINAL : tear everything down and we're done.
        private void finalizeRestore() {
            if (MORE_DEBUG) Slog.d(TAG, "finishing restore mObserver=" + mObserver);

            try {
                mTransport.finishRestore();
            } catch (Exception e) {
                Slog.e(TAG, "Error finishing restore", e);
            }

            // Tell the observer we're done
            if (mObserver != null) {
                try {
                    mObserver.restoreFinished(mStatus);
                } catch (RemoteException e) {
                    Slog.d(TAG, "Restore observer died at restoreFinished");
                }
            }

            // Clear any ongoing session timeout.
            mBackupHandler.removeMessages(MSG_RESTORE_SESSION_TIMEOUT);

            // If we have a PM token, we must under all circumstances be sure to
            // handshake when we've finished.
            if (mPmToken > 0) {
                if (MORE_DEBUG) Slog.v(TAG, "finishing PM token " + mPmToken);
                try {
                    mPackageManagerBinder.finishPackageInstall(mPmToken, mDidLaunch);
                } catch (RemoteException e) { /* can't happen */ }
            } else {
                // We were invoked via an active restore session, not by the Package
                // Manager, so start up the session timeout again.
                mBackupHandler.sendEmptyMessageDelayed(MSG_RESTORE_SESSION_TIMEOUT,
                        TIMEOUT_RESTORE_INTERVAL);
            }

            // Kick off any work that may be needed regarding app widget restores
            // TODO: http://b/22388012
            AppWidgetBackupBridge.restoreFinished(UserHandle.USER_SYSTEM);

            // If this was a full-system restore, record the ancestral
            // dataset information
            if (mIsSystemRestore && mPmAgent != null) {
                mAncestralPackages = mPmAgent.getRestoredPackages();
                mAncestralToken = mToken;
                writeRestoreTokens();
            }

            // done; we can finally release the wakelock and be legitimately done.
            Slog.i(TAG, "Restore complete.");

            synchronized (mPendingRestores) {
                if (mPendingRestores.size() > 0) {
                    if (DEBUG) {
                        Slog.d(TAG, "Starting next pending restore.");
                    }
                    PerformUnifiedRestoreTask task = mPendingRestores.remove();
                    mBackupHandler.sendMessage(
                            mBackupHandler.obtainMessage(MSG_BACKUP_RESTORE_STEP, task));

                } else {
                    mIsRestoreInProgress = false;
                    if (MORE_DEBUG) {
                        Slog.d(TAG, "No pending restores.");
                    }
                }
            }

            mWakelock.release();
        }

        void keyValueAgentErrorCleanup() {
            // If the agent fails restore, it might have put the app's data
            // into an incoherent state.  For consistency we wipe its data
            // again in this case before continuing with normal teardown
            clearApplicationDataSynchronous(mCurrentPackage.packageName);
            keyValueAgentCleanup();
        }

        // TODO: clean up naming; this is now used at finish by both k/v and stream restores
        void keyValueAgentCleanup() {
            mBackupDataName.delete();
            mStageName.delete();
            try { if (mBackupData != null) mBackupData.close(); } catch (IOException e) {}
            try { if (mNewState != null) mNewState.close(); } catch (IOException e) {}
            mBackupData = mNewState = null;

            // if everything went okay, remember the recorded state now
            //
            // !!! TODO: the restored data could be migrated on the server
            // side into the current dataset.  In that case the new state file
            // we just created would reflect the data already extant in the
            // backend, so there'd be nothing more to do.  Until that happens,
            // however, we need to make sure that we record the data to the
            // current backend dataset.  (Yes, this means shipping the data over
            // the wire in both directions.  That's bad, but consistency comes
            // first, then efficiency.)  Once we introduce server-side data
            // migration to the newly-restored device's dataset, we will change
            // the following from a discard of the newly-written state to the
            // "correct" operation of renaming into the canonical state blob.
            mNewStateName.delete();                      // TODO: remove; see above comment
            //mNewStateName.renameTo(mSavedStateName);   // TODO: replace with this

            // If this wasn't the PM pseudopackage, tear down the agent side
            if (mCurrentPackage.applicationInfo != null) {
                // unbind and tidy up even on timeout or failure
                try {
                    mActivityManager.unbindBackupAgent(mCurrentPackage.applicationInfo);

                    // The agent was probably running with a stub Application object,
                    // which isn't a valid run mode for the main app logic.  Shut
                    // down the app so that next time it's launched, it gets the
                    // usual full initialization.  Note that this is only done for
                    // full-system restores: when a single app has requested a restore,
                    // it is explicitly not killed following that operation.
                    //
                    // We execute this kill when these conditions hold:
                    //    1. it's not a system-uid process,
                    //    2. the app did not request its own restore (mTargetPackage == null), and either
                    //    3a. the app is a full-data target (TYPE_FULL_STREAM) or
                    //     b. the app does not state android:killAfterRestore="false" in its manifest
                    final int appFlags = mCurrentPackage.applicationInfo.flags;
                    final boolean killAfterRestore =
                            (mCurrentPackage.applicationInfo.uid >= Process.FIRST_APPLICATION_UID)
                            && ((mRestoreDescription.getDataType() == RestoreDescription.TYPE_FULL_STREAM)
                                    || ((appFlags & ApplicationInfo.FLAG_KILL_AFTER_RESTORE) != 0));

                    if (mTargetPackage == null && killAfterRestore) {
                        if (DEBUG) Slog.d(TAG, "Restore complete, killing host process of "
                                + mCurrentPackage.applicationInfo.processName);
                        mActivityManager.killApplicationProcess(
                                mCurrentPackage.applicationInfo.processName,
                                mCurrentPackage.applicationInfo.uid);
                    }
                } catch (RemoteException e) {
                    // can't happen; we run in the same process as the activity manager
                }
            }

            // The caller is responsible for reestablishing the state machine; our
            // responsibility here is to clear the decks for whatever comes next.
            mBackupHandler.removeMessages(MSG_RESTORE_OPERATION_TIMEOUT, this);
        }

        @Override
        public void operationComplete(long unusedResult) {
            removeOperation(mEphemeralOpToken);
            if (MORE_DEBUG) {
                Slog.i(TAG, "operationComplete() during restore: target="
                        + mCurrentPackage.packageName
                        + " state=" + mState);
            }

            final UnifiedRestoreState nextState;
            switch (mState) {
                case INITIAL:
                    // We've just (manually) restored the PMBA.  It doesn't need the
                    // additional restore-finished callback so we bypass that and go
                    // directly to running the queue.
                    nextState = UnifiedRestoreState.RUNNING_QUEUE;
                    break;

                case RESTORE_KEYVALUE:
                case RESTORE_FULL: {
                    // Okay, we've just heard back from the agent that it's done with
                    // the restore itself.  We now have to send the same agent its
                    // doRestoreFinished() callback, so roll into that state.
                    nextState = UnifiedRestoreState.RESTORE_FINISHED;
                    break;
                }

                case RESTORE_FINISHED: {
                    // Okay, we're done with this package.  Tidy up and go on to the next
                    // app in the queue.
                    int size = (int) mBackupDataName.length();
                    EventLog.writeEvent(EventLogTags.RESTORE_PACKAGE,
                            mCurrentPackage.packageName, size);

                    // Just go back to running the restore queue
                    keyValueAgentCleanup();

                    // If there was widget state associated with this app, get the OS to
                    // incorporate it into current bookeeping and then pass that along to
                    // the app as part of the restore-time work.
                    if (mWidgetData != null) {
                        restoreWidgetData(mCurrentPackage.packageName, mWidgetData);
                    }

                    nextState = UnifiedRestoreState.RUNNING_QUEUE;
                    break;
                }

                default: {
                    // Some kind of horrible semantic error; we're in an unexpected state.
                    // Back off hard and wind up.
                    Slog.e(TAG, "Unexpected restore callback into state " + mState);
                    keyValueAgentErrorCleanup();
                    nextState = UnifiedRestoreState.FINAL;
                    break;
                }
            }

            executeNextState(nextState);
        }

        // A call to agent.doRestore() or agent.doRestoreFinished() has timed out
        @Override
        public void handleCancel(boolean cancelAll) {
            removeOperation(mEphemeralOpToken);
            Slog.e(TAG, "Timeout restoring application " + mCurrentPackage.packageName);
            mMonitor = monitorEvent(mMonitor,
                    BackupManagerMonitor.LOG_EVENT_ID_KEY_VALUE_RESTORE_TIMEOUT,
                    mCurrentPackage, BackupManagerMonitor.LOG_EVENT_CATEGORY_AGENT, null);
            EventLog.writeEvent(EventLogTags.RESTORE_AGENT_FAILURE,
                    mCurrentPackage.packageName, "restore timeout");
            // Handle like an agent that threw on invocation: wipe it and go on to the next
            keyValueAgentErrorCleanup();
            executeNextState(UnifiedRestoreState.RUNNING_QUEUE);
        }

        void executeNextState(UnifiedRestoreState nextState) {
            if (MORE_DEBUG) Slog.i(TAG, " => executing next step on "
                    + this + " nextState=" + nextState);
            mState = nextState;
            Message msg = mBackupHandler.obtainMessage(MSG_BACKUP_RESTORE_STEP, this);
            mBackupHandler.sendMessage(msg);
        }

        // restore observer support
        void sendStartRestore(int numPackages) {
            if (mObserver != null) {
                try {
                    mObserver.restoreStarting(numPackages);
                } catch (RemoteException e) {
                    Slog.w(TAG, "Restore observer went away: startRestore");
                    mObserver = null;
                }
            }
        }

        void sendOnRestorePackage(String name) {
            if (mObserver != null) {
                if (mObserver != null) {
                    try {
                        mObserver.onUpdate(mCount, name);
                    } catch (RemoteException e) {
                        Slog.d(TAG, "Restore observer died in onUpdate");
                        mObserver = null;
                    }
                }
            }
        }

        void sendEndRestore() {
            if (mObserver != null) {
                try {
                    mObserver.restoreFinished(mStatus);
                } catch (RemoteException e) {
                    Slog.w(TAG, "Restore observer went away: endRestore");
                    mObserver = null;
                }
            }
        }
    }

    class PerformClearTask implements Runnable {
        IBackupTransport mTransport;
        PackageInfo mPackage;

        PerformClearTask(IBackupTransport transport, PackageInfo packageInfo) {
            mTransport = transport;
            mPackage = packageInfo;
        }

        public void run() {
            try {
                // Clear the on-device backup state to ensure a full backup next time
                File stateDir = new File(mBaseStateDir, mTransport.transportDirName());
                File stateFile = new File(stateDir, mPackage.packageName);
                stateFile.delete();

                // Tell the transport to remove all the persistent storage for the app
                // TODO - need to handle failures
                mTransport.clearBackupData(mPackage);
            } catch (Exception e) {
                Slog.e(TAG, "Transport threw clearing data for " + mPackage + ": " + e.getMessage());
            } finally {
                try {
                    // TODO - need to handle failures
                    mTransport.finishBackup();
                } catch (Exception e) {
                    // Nothing we can do here, alas
                    Slog.e(TAG, "Unable to mark clear operation finished: " + e.getMessage());
                }

                // Last but not least, release the cpu
                mWakelock.release();
            }
        }
    }

    class PerformInitializeTask implements Runnable {
        String[] mQueue;
        IBackupObserver mObserver;

        PerformInitializeTask(String[] transportNames, IBackupObserver observer) {
            mQueue = transportNames;
            mObserver = observer;
        }

        private void notifyResult(String target, int status) {
            try {
                if (mObserver != null) {
                    mObserver.onResult(target, status);
                }
            } catch (RemoteException ignored) {
                mObserver = null;       // don't try again
            }
        }

        private void notifyFinished(int status) {
            try {
                if (mObserver != null) {
                    mObserver.backupFinished(status);
                }
            } catch (RemoteException ignored) {
                mObserver = null;
            }
        }

        public void run() {
            // mWakelock is *acquired* when execution begins here
            int result = BackupTransport.TRANSPORT_OK;
            try {
                for (String transportName : mQueue) {
                    IBackupTransport transport =
                            mTransportManager.getTransportBinder(transportName);
                    if (transport == null) {
                        Slog.e(TAG, "Requested init for " + transportName + " but not found");
                        continue;
                    }

                    Slog.i(TAG, "Initializing (wiping) backup transport storage: " + transportName);
                    EventLog.writeEvent(EventLogTags.BACKUP_START, transport.transportDirName());
                    long startRealtime = SystemClock.elapsedRealtime();
                    int status = transport.initializeDevice();

                    if (status == BackupTransport.TRANSPORT_OK) {
                        status = transport.finishBackup();
                    }

                    // Okay, the wipe really happened.  Clean up our local bookkeeping.
                    if (status == BackupTransport.TRANSPORT_OK) {
                        Slog.i(TAG, "Device init successful");
                        int millis = (int) (SystemClock.elapsedRealtime() - startRealtime);
                        EventLog.writeEvent(EventLogTags.BACKUP_INITIALIZE);
                        resetBackupState(new File(mBaseStateDir, transport.transportDirName()));
                        EventLog.writeEvent(EventLogTags.BACKUP_SUCCESS, 0, millis);
                        synchronized (mQueueLock) {
                            recordInitPendingLocked(false, transportName);
                        }
                        notifyResult(transportName, BackupTransport.TRANSPORT_OK);
                    } else {
                        // If this didn't work, requeue this one and try again
                        // after a suitable interval
                        Slog.e(TAG, "Transport error in initializeDevice()");
                        EventLog.writeEvent(EventLogTags.BACKUP_TRANSPORT_FAILURE, "(initialize)");
                        synchronized (mQueueLock) {
                            recordInitPendingLocked(true, transportName);
                        }
                        notifyResult(transportName, status);
                        result = status;

                        // do this via another alarm to make sure of the wakelock states
                        long delay = transport.requestBackupTime();
                        Slog.w(TAG, "Init failed on " + transportName + " resched in " + delay);
                        mAlarmManager.set(AlarmManager.RTC_WAKEUP,
                                System.currentTimeMillis() + delay, mRunInitIntent);
                    }
                }
            } catch (Exception e) {
                Slog.e(TAG, "Unexpected error performing init", e);
                result = BackupTransport.TRANSPORT_ERROR;
            } finally {
                // Done; release the wakelock
                notifyFinished(result);
                mWakelock.release();
            }
        }
    }

    private void dataChangedImpl(String packageName) {
        HashSet<String> targets = dataChangedTargets(packageName);
        dataChangedImpl(packageName, targets);
    }

    private void dataChangedImpl(String packageName, HashSet<String> targets) {
        // Record that we need a backup pass for the caller.  Since multiple callers
        // may share a uid, we need to note all candidates within that uid and schedule
        // a backup pass for each of them.
        if (targets == null) {
            Slog.w(TAG, "dataChanged but no participant pkg='" + packageName + "'"
                   + " uid=" + Binder.getCallingUid());
            return;
        }

        synchronized (mQueueLock) {
            // Note that this client has made data changes that need to be backed up
            if (targets.contains(packageName)) {
                // Add the caller to the set of pending backups.  If there is
                // one already there, then overwrite it, but no harm done.
                BackupRequest req = new BackupRequest(packageName);
                if (mPendingBackups.put(packageName, req) == null) {
                    if (MORE_DEBUG) Slog.d(TAG, "Now staging backup of " + packageName);

                    // Journal this request in case of crash.  The put()
                    // operation returned null when this package was not already
                    // in the set; we want to avoid touching the disk redundantly.
                    writeToJournalLocked(packageName);
                }
            }
        }

        // ...and schedule a backup pass if necessary
        KeyValueBackupJob.schedule(mContext);
    }

    // Note: packageName is currently unused, but may be in the future
    private HashSet<String> dataChangedTargets(String packageName) {
        // If the caller does not hold the BACKUP permission, it can only request a
        // backup of its own data.
        if ((mContext.checkPermission(android.Manifest.permission.BACKUP, Binder.getCallingPid(),
                Binder.getCallingUid())) == PackageManager.PERMISSION_DENIED) {
            synchronized (mBackupParticipants) {
                return mBackupParticipants.get(Binder.getCallingUid());
            }
        }

        // a caller with full permission can ask to back up any participating app
        HashSet<String> targets = new HashSet<String>();
        if (PACKAGE_MANAGER_SENTINEL.equals(packageName)) {
            targets.add(PACKAGE_MANAGER_SENTINEL);
        } else {
            synchronized (mBackupParticipants) {
                int N = mBackupParticipants.size();
                for (int i = 0; i < N; i++) {
                    HashSet<String> s = mBackupParticipants.valueAt(i);
                    if (s != null) {
                        targets.addAll(s);
                    }
                }
            }
        }
        return targets;
    }

    private void writeToJournalLocked(String str) {
        RandomAccessFile out = null;
        try {
            if (mJournal == null) mJournal = File.createTempFile("journal", null, mJournalDir);
            out = new RandomAccessFile(mJournal, "rws");
            out.seek(out.length());
            out.writeUTF(str);
        } catch (IOException e) {
            Slog.e(TAG, "Can't write " + str + " to backup journal", e);
            mJournal = null;
        } finally {
            try { if (out != null) out.close(); } catch (IOException e) {}
        }
    }

    // ----- IBackupManager binder interface -----

    @Override
    public void dataChanged(final String packageName) {
        final int callingUserHandle = UserHandle.getCallingUserId();
        if (callingUserHandle != UserHandle.USER_SYSTEM) {
            // TODO: http://b/22388012
            // App is running under a non-owner user profile.  For now, we do not back
            // up data from secondary user profiles.
            // TODO: backups for all user profiles although don't add backup for profiles
            // without adding admin control in DevicePolicyManager.
            if (MORE_DEBUG) {
                Slog.v(TAG, "dataChanged(" + packageName + ") ignored because it's user "
                        + callingUserHandle);
            }
            return;
        }

        final HashSet<String> targets = dataChangedTargets(packageName);
        if (targets == null) {
            Slog.w(TAG, "dataChanged but no participant pkg='" + packageName + "'"
                   + " uid=" + Binder.getCallingUid());
            return;
        }

        mBackupHandler.post(new Runnable() {
                public void run() {
                    dataChangedImpl(packageName, targets);
                }
            });
    }

    // Run an initialize operation for the given transport
    @Override
    public void initializeTransports(String[] transportNames, IBackupObserver observer) {
        mContext.enforceCallingPermission(android.Manifest.permission.BACKUP, "initializeTransport");
        if (MORE_DEBUG) {
            Slog.v(TAG, "initializeTransports() of " + transportNames);
        }

        final long oldId = Binder.clearCallingIdentity();
        try {
            mWakelock.acquire();
            mBackupHandler.post(new PerformInitializeTask(transportNames, observer));
        } finally {
            Binder.restoreCallingIdentity(oldId);
        }
    }

    // Clear the given package's backup data from the current transport
    @Override
    public void clearBackupData(String transportName, String packageName) {
        if (DEBUG) Slog.v(TAG, "clearBackupData() of " + packageName + " on " + transportName);
        PackageInfo info;
        try {
            info = mPackageManager.getPackageInfo(packageName, PackageManager.GET_SIGNATURES);
        } catch (NameNotFoundException e) {
            Slog.d(TAG, "No such package '" + packageName + "' - not clearing backup data");
            return;
        }

        // If the caller does not hold the BACKUP permission, it can only request a
        // wipe of its own backed-up data.
        HashSet<String> apps;
        if ((mContext.checkPermission(android.Manifest.permission.BACKUP, Binder.getCallingPid(),
                Binder.getCallingUid())) == PackageManager.PERMISSION_DENIED) {
            apps = mBackupParticipants.get(Binder.getCallingUid());
        } else {
            // a caller with full permission can ask to back up any participating app
            // !!! TODO: allow data-clear of ANY app?
            if (MORE_DEBUG) Slog.v(TAG, "Privileged caller, allowing clear of other apps");
            apps = new HashSet<String>();
            int N = mBackupParticipants.size();
            for (int i = 0; i < N; i++) {
                HashSet<String> s = mBackupParticipants.valueAt(i);
                if (s != null) {
                    apps.addAll(s);
                }
            }
        }

        // Is the given app an available participant?
        if (apps.contains(packageName)) {
            // found it; fire off the clear request
            if (MORE_DEBUG) Slog.v(TAG, "Found the app - running clear process");
            mBackupHandler.removeMessages(MSG_RETRY_CLEAR);
            synchronized (mQueueLock) {
                final IBackupTransport transport =
                        mTransportManager.getTransportBinder(transportName);
                if (transport == null) {
                    // transport is currently unavailable -- make sure to retry
                    Message msg = mBackupHandler.obtainMessage(MSG_RETRY_CLEAR,
                            new ClearRetryParams(transportName, packageName));
                    mBackupHandler.sendMessageDelayed(msg, TRANSPORT_RETRY_INTERVAL);
                    return;
                }
                long oldId = Binder.clearCallingIdentity();
                mWakelock.acquire();
                Message msg = mBackupHandler.obtainMessage(MSG_RUN_CLEAR,
                        new ClearParams(transport, info));
                mBackupHandler.sendMessage(msg);
                Binder.restoreCallingIdentity(oldId);
            }
        }
    }

    // Run a backup pass immediately for any applications that have declared
    // that they have pending updates.
    @Override
    public void backupNow() {
        mContext.enforceCallingOrSelfPermission(android.Manifest.permission.BACKUP, "backupNow");

        final PowerSaveState result =
                mPowerManager.getPowerSaveState(ServiceType.KEYVALUE_BACKUP);
        if (result.batterySaverEnabled) {
            if (DEBUG) Slog.v(TAG, "Not running backup while in battery save mode");
            KeyValueBackupJob.schedule(mContext);   // try again in several hours
        } else {
            if (DEBUG) Slog.v(TAG, "Scheduling immediate backup pass");
            synchronized (mQueueLock) {
                // Fire the intent that kicks off the whole shebang...
                try {
                    mRunBackupIntent.send();
                } catch (PendingIntent.CanceledException e) {
                    // should never happen
                    Slog.e(TAG, "run-backup intent cancelled!");
                }

                // ...and cancel any pending scheduled job, because we've just superseded it
                KeyValueBackupJob.cancel(mContext);
            }
        }
    }

    boolean deviceIsProvisioned() {
        final ContentResolver resolver = mContext.getContentResolver();
        return (Settings.Global.getInt(resolver, Settings.Global.DEVICE_PROVISIONED, 0) != 0);
    }

    // Run a backup pass for the given packages, writing the resulting data stream
    // to the supplied file descriptor.  This method is synchronous and does not return
    // to the caller until the backup has been completed.
    //
    // This is the variant used by 'adb backup'; it requires on-screen confirmation
    // by the user because it can be used to offload data over untrusted USB.
    @Override
    public void adbBackup(ParcelFileDescriptor fd, boolean includeApks, boolean includeObbs,
            boolean includeShared, boolean doWidgets, boolean doAllApps, boolean includeSystem,
            boolean compress, boolean doKeyValue, String[] pkgList) {
        mContext.enforceCallingPermission(android.Manifest.permission.BACKUP, "adbBackup");

        final int callingUserHandle = UserHandle.getCallingUserId();
        // TODO: http://b/22388012
        if (callingUserHandle != UserHandle.USER_SYSTEM) {
            throw new IllegalStateException("Backup supported only for the device owner");
        }

        // Validate
        if (!doAllApps) {
            if (!includeShared) {
                // If we're backing up shared data (sdcard or equivalent), then we can run
                // without any supplied app names.  Otherwise, we'd be doing no work, so
                // report the error.
                if (pkgList == null || pkgList.length == 0) {
                    throw new IllegalArgumentException(
                            "Backup requested but neither shared nor any apps named");
                }
            }
        }

        long oldId = Binder.clearCallingIdentity();
        try {
            // Doesn't make sense to do a full backup prior to setup
            if (!deviceIsProvisioned()) {
                Slog.i(TAG, "Backup not supported before setup");
                return;
            }

            if (DEBUG) Slog.v(TAG, "Requesting backup: apks=" + includeApks + " obb=" + includeObbs
                    + " shared=" + includeShared + " all=" + doAllApps + " system="
                    + includeSystem + " includekeyvalue=" + doKeyValue + " pkgs=" + pkgList);
            Slog.i(TAG, "Beginning adb backup...");

            AdbBackupParams params = new AdbBackupParams(fd, includeApks, includeObbs,
                    includeShared, doWidgets, doAllApps, includeSystem, compress, doKeyValue,
                    pkgList);
            final int token = generateRandomIntegerToken();
            synchronized (mAdbBackupRestoreConfirmations) {
                mAdbBackupRestoreConfirmations.put(token, params);
            }

            // start up the confirmation UI
            if (DEBUG) Slog.d(TAG, "Starting backup confirmation UI, token=" + token);
            if (!startConfirmationUi(token, FullBackup.FULL_BACKUP_INTENT_ACTION)) {
                Slog.e(TAG, "Unable to launch backup confirmation UI");
                mAdbBackupRestoreConfirmations.delete(token);
                return;
            }

            // make sure the screen is lit for the user interaction
            mPowerManager.userActivity(SystemClock.uptimeMillis(),
                    PowerManager.USER_ACTIVITY_EVENT_OTHER,
                    0);

            // start the confirmation countdown
            startConfirmationTimeout(token, params);

            // wait for the backup to be performed
            if (DEBUG) Slog.d(TAG, "Waiting for backup completion...");
            waitForCompletion(params);
        } finally {
            try {
                fd.close();
            } catch (IOException e) {
                // just eat it
            }
            Binder.restoreCallingIdentity(oldId);
            Slog.d(TAG, "Adb backup processing complete.");
        }
    }

    @Override
    public void fullTransportBackup(String[] pkgNames) {
        mContext.enforceCallingPermission(android.Manifest.permission.BACKUP,
                "fullTransportBackup");

        final int callingUserHandle = UserHandle.getCallingUserId();
        // TODO: http://b/22388012
        if (callingUserHandle != UserHandle.USER_SYSTEM) {
            throw new IllegalStateException("Restore supported only for the device owner");
        }

        if (!fullBackupAllowable(mTransportManager.getCurrentTransportBinder())) {
            Slog.i(TAG, "Full backup not currently possible -- key/value backup not yet run?");
        } else {
            if (DEBUG) {
                Slog.d(TAG, "fullTransportBackup()");
            }

            final long oldId = Binder.clearCallingIdentity();
            try {
                CountDownLatch latch = new CountDownLatch(1);
                PerformFullTransportBackupTask task = new PerformFullTransportBackupTask(null,
                        pkgNames, false, null, latch, null, null, false /* userInitiated */);
                // Acquiring wakelock for PerformFullTransportBackupTask before its start.
                mWakelock.acquire();
                (new Thread(task, "full-transport-master")).start();
                do {
                    try {
                        latch.await();
                        break;
                    } catch (InterruptedException e) {
                        // Just go back to waiting for the latch to indicate completion
                    }
                } while (true);

                // We just ran a backup on these packages, so kick them to the end of the queue
                final long now = System.currentTimeMillis();
                for (String pkg : pkgNames) {
                    enqueueFullBackup(pkg, now);
                }
            } finally {
                Binder.restoreCallingIdentity(oldId);
            }
        }

        if (DEBUG) {
            Slog.d(TAG, "Done with full transport backup.");
        }
    }

    @Override
    public void adbRestore(ParcelFileDescriptor fd) {
        mContext.enforceCallingPermission(android.Manifest.permission.BACKUP, "adbRestore");

        final int callingUserHandle = UserHandle.getCallingUserId();
        // TODO: http://b/22388012
        if (callingUserHandle != UserHandle.USER_SYSTEM) {
            throw new IllegalStateException("Restore supported only for the device owner");
        }

        long oldId = Binder.clearCallingIdentity();

        try {
            // Check whether the device has been provisioned -- we don't handle
            // full restores prior to completing the setup process.
            if (!deviceIsProvisioned()) {
                Slog.i(TAG, "Full restore not permitted before setup");
                return;
            }

            Slog.i(TAG, "Beginning restore...");

            AdbRestoreParams params = new AdbRestoreParams(fd);
            final int token = generateRandomIntegerToken();
            synchronized (mAdbBackupRestoreConfirmations) {
                mAdbBackupRestoreConfirmations.put(token, params);
            }

            // start up the confirmation UI
            if (DEBUG) Slog.d(TAG, "Starting restore confirmation UI, token=" + token);
            if (!startConfirmationUi(token, FullBackup.FULL_RESTORE_INTENT_ACTION)) {
                Slog.e(TAG, "Unable to launch restore confirmation");
                mAdbBackupRestoreConfirmations.delete(token);
                return;
            }

            // make sure the screen is lit for the user interaction
            mPowerManager.userActivity(SystemClock.uptimeMillis(),
                    PowerManager.USER_ACTIVITY_EVENT_OTHER,
                    0);

            // start the confirmation countdown
            startConfirmationTimeout(token, params);

            // wait for the restore to be performed
            if (DEBUG) Slog.d(TAG, "Waiting for restore completion...");
            waitForCompletion(params);
        } finally {
            try {
                fd.close();
            } catch (IOException e) {
                Slog.w(TAG, "Error trying to close fd after adb restore: " + e);
            }
            Binder.restoreCallingIdentity(oldId);
            Slog.i(TAG, "adb restore processing complete.");
        }
    }

    boolean startConfirmationUi(int token, String action) {
        try {
            Intent confIntent = new Intent(action);
            confIntent.setClassName("com.android.backupconfirm",
                    "com.android.backupconfirm.BackupRestoreConfirmation");
            confIntent.putExtra(FullBackup.CONF_TOKEN_INTENT_EXTRA, token);
            confIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            mContext.startActivityAsUser(confIntent, UserHandle.SYSTEM);
        } catch (ActivityNotFoundException e) {
            return false;
        }
        return true;
    }

    void startConfirmationTimeout(int token, AdbParams params) {
        if (MORE_DEBUG) Slog.d(TAG, "Posting conf timeout msg after "
                + TIMEOUT_FULL_CONFIRMATION + " millis");
        Message msg = mBackupHandler.obtainMessage(MSG_FULL_CONFIRMATION_TIMEOUT,
                token, 0, params);
        mBackupHandler.sendMessageDelayed(msg, TIMEOUT_FULL_CONFIRMATION);
    }

    void waitForCompletion(AdbParams params) {
        synchronized (params.latch) {
            while (params.latch.get() == false) {
                try {
                    params.latch.wait();
                } catch (InterruptedException e) { /* never interrupted */ }
            }
        }
    }

    void signalAdbBackupRestoreCompletion(AdbParams params) {
        synchronized (params.latch) {
            params.latch.set(true);
            params.latch.notifyAll();
        }
    }

    // Confirm that the previously-requested full backup/restore operation can proceed.  This
    // is used to require a user-facing disclosure about the operation.
    @Override
    public void acknowledgeAdbBackupOrRestore(int token, boolean allow,
            String curPassword, String encPpassword, IFullBackupRestoreObserver observer) {
        if (DEBUG) Slog.d(TAG, "acknowledgeAdbBackupOrRestore : token=" + token
                + " allow=" + allow);

        // TODO: possibly require not just this signature-only permission, but even
        // require that the specific designated confirmation-UI app uid is the caller?
        mContext.enforceCallingPermission(android.Manifest.permission.BACKUP, "acknowledgeAdbBackupOrRestore");

        long oldId = Binder.clearCallingIdentity();
        try {

            AdbParams params;
            synchronized (mAdbBackupRestoreConfirmations) {
                params = mAdbBackupRestoreConfirmations.get(token);
                if (params != null) {
                    mBackupHandler.removeMessages(MSG_FULL_CONFIRMATION_TIMEOUT, params);
                    mAdbBackupRestoreConfirmations.delete(token);

                    if (allow) {
                        final int verb = params instanceof AdbBackupParams
                                ? MSG_RUN_ADB_BACKUP
                                : MSG_RUN_ADB_RESTORE;

                        params.observer = observer;
                        params.curPassword = curPassword;

                        params.encryptPassword = encPpassword;

                        if (MORE_DEBUG) Slog.d(TAG, "Sending conf message with verb " + verb);
                        mWakelock.acquire();
                        Message msg = mBackupHandler.obtainMessage(verb, params);
                        mBackupHandler.sendMessage(msg);
                    } else {
                        Slog.w(TAG, "User rejected full backup/restore operation");
                        // indicate completion without having actually transferred any data
                        signalAdbBackupRestoreCompletion(params);
                    }
                } else {
                    Slog.w(TAG, "Attempted to ack full backup/restore with invalid token");
                }
            }
        } finally {
            Binder.restoreCallingIdentity(oldId);
        }
    }

    private static boolean backupSettingMigrated(int userId) {
        File base = new File(Environment.getDataDirectory(), "backup");
        File enableFile = new File(base, BACKUP_ENABLE_FILE);
        return enableFile.exists();
    }

    private static boolean readBackupEnableState(int userId) {
        File base = new File(Environment.getDataDirectory(), "backup");
        File enableFile = new File(base, BACKUP_ENABLE_FILE);
        if (enableFile.exists()) {
            try (FileInputStream fin = new FileInputStream(enableFile)) {
                int state = fin.read();
                return state != 0;
            } catch (IOException e) {
                // can't read the file; fall through to assume disabled
                Slog.e(TAG, "Cannot read enable state; assuming disabled");
            }
        } else {
            if (DEBUG) {
                Slog.i(TAG, "isBackupEnabled() => false due to absent settings file");
            }
        }
        return false;
    }

    private static void writeBackupEnableState(boolean enable, int userId) {
        File base = new File(Environment.getDataDirectory(), "backup");
        File enableFile = new File(base, BACKUP_ENABLE_FILE);
        File stage = new File(base, BACKUP_ENABLE_FILE + "-stage");
        FileOutputStream fout = null;
        try {
            fout = new FileOutputStream(stage);
            fout.write(enable ? 1 : 0);
            fout.close();
            stage.renameTo(enableFile);
            // will be synced immediately by the try-with-resources call to close()
        } catch (IOException|RuntimeException e) {
            // Whoops; looks like we're doomed.  Roll everything out, disabled,
            // including the legacy state.
            Slog.e(TAG, "Unable to record backup enable state; reverting to disabled: "
                    + e.getMessage());

            final ContentResolver r = sInstance.mContext.getContentResolver();
            Settings.Secure.putStringForUser(r,
                    Settings.Secure.BACKUP_ENABLED, null, userId);
            enableFile.delete();
            stage.delete();
        } finally {
            IoUtils.closeQuietly(fout);
        }
    }

    // Enable/disable backups
    @Override
    public void setBackupEnabled(boolean enable) {
        mContext.enforceCallingOrSelfPermission(android.Manifest.permission.BACKUP,
                "setBackupEnabled");

        Slog.i(TAG, "Backup enabled => " + enable);

        long oldId = Binder.clearCallingIdentity();
        try {
            boolean wasEnabled = mEnabled;
            synchronized (this) {
                writeBackupEnableState(enable, UserHandle.USER_SYSTEM);
                mEnabled = enable;
            }

            synchronized (mQueueLock) {
                if (enable && !wasEnabled && mProvisioned) {
                    // if we've just been enabled, start scheduling backup passes
                    KeyValueBackupJob.schedule(mContext);
                    scheduleNextFullBackupJob(0);
                } else if (!enable) {
                    // No longer enabled, so stop running backups
                    if (MORE_DEBUG) Slog.i(TAG, "Opting out of backup");

                    KeyValueBackupJob.cancel(mContext);

                    // This also constitutes an opt-out, so we wipe any data for
                    // this device from the backend.  We start that process with
                    // an alarm in order to guarantee wakelock states.
                    if (wasEnabled && mProvisioned) {
                        // NOTE: we currently flush every registered transport, not just
                        // the currently-active one.
                        String[] allTransports = mTransportManager.getBoundTransportNames();
                        // build the set of transports for which we are posting an init
                        for (String transport : allTransports) {
                            recordInitPendingLocked(true, transport);
                        }
                        mAlarmManager.set(AlarmManager.RTC_WAKEUP, System.currentTimeMillis(),
                                mRunInitIntent);
                    }
                }
            }
        } finally {
            Binder.restoreCallingIdentity(oldId);
        }
    }

    // Enable/disable automatic restore of app data at install time
    @Override
    public void setAutoRestore(boolean doAutoRestore) {
        mContext.enforceCallingOrSelfPermission(android.Manifest.permission.BACKUP,
                "setAutoRestore");

        Slog.i(TAG, "Auto restore => " + doAutoRestore);

        final long oldId = Binder.clearCallingIdentity();
        try {
            synchronized (this) {
                Settings.Secure.putInt(mContext.getContentResolver(),
                        Settings.Secure.BACKUP_AUTO_RESTORE, doAutoRestore ? 1 : 0);
                mAutoRestore = doAutoRestore;
            }
        } finally {
            Binder.restoreCallingIdentity(oldId);
        }
    }

    // Mark the backup service as having been provisioned
    @Override
    public void setBackupProvisioned(boolean available) {
        mContext.enforceCallingOrSelfPermission(android.Manifest.permission.BACKUP,
                "setBackupProvisioned");
        /*
         * This is now a no-op; provisioning is simply the device's own setup state.
         */
    }

    // Report whether the backup mechanism is currently enabled
    @Override
    public boolean isBackupEnabled() {
        mContext.enforceCallingOrSelfPermission(android.Manifest.permission.BACKUP, "isBackupEnabled");
        return mEnabled;    // no need to synchronize just to read it
    }

    // Report the name of the currently active transport
    @Override
    public String getCurrentTransport() {
        mContext.enforceCallingOrSelfPermission(android.Manifest.permission.BACKUP,
                "getCurrentTransport");
        String currentTransport = mTransportManager.getCurrentTransportName();
        if (MORE_DEBUG) Slog.v(TAG, "... getCurrentTransport() returning " + currentTransport);
        return currentTransport;
    }

    // Report all known, available backup transports
    @Override
    public String[] listAllTransports() {
        mContext.enforceCallingOrSelfPermission(android.Manifest.permission.BACKUP, "listAllTransports");

        return mTransportManager.getBoundTransportNames();
    }

    @Override
    public ComponentName[] listAllTransportComponents() {
        mContext.enforceCallingOrSelfPermission(android.Manifest.permission.BACKUP,
                "listAllTransportComponents");
        return mTransportManager.getAllTransportCompenents();
    }

    @Override
    public String[] getTransportWhitelist() {
        // No permission check, intentionally.
        Set<ComponentName> whitelistedComponents = mTransportManager.getTransportWhitelist();
        String[] whitelistedTransports = new String[whitelistedComponents.size()];
        int i = 0;
        for (ComponentName component : whitelistedComponents) {
            whitelistedTransports[i] = component.flattenToShortString();
            i++;
        }
        return whitelistedTransports;
    }

    // Select which transport to use for the next backup operation.
    @Override
    public String selectBackupTransport(String transport) {
        mContext.enforceCallingOrSelfPermission(android.Manifest.permission.BACKUP,
                "selectBackupTransport");

        final long oldId = Binder.clearCallingIdentity();
        try {
            String prevTransport = mTransportManager.selectTransport(transport);
            updateStateForTransport(transport);
            Slog.v(TAG, "selectBackupTransport() set " + mTransportManager.getCurrentTransportName()
                    + " returning " + prevTransport);
            return prevTransport;
        } finally {
            Binder.restoreCallingIdentity(oldId);
        }
    }

    @Override
    public void selectBackupTransportAsync(final ComponentName transport,
            final ISelectBackupTransportCallback listener) {
        mContext.enforceCallingOrSelfPermission(android.Manifest.permission.BACKUP,
                "selectBackupTransportAsync");

        final long oldId = Binder.clearCallingIdentity();

        Slog.v(TAG, "selectBackupTransportAsync() called with transport " +
                transport.flattenToShortString());

        mTransportManager.ensureTransportReady(transport, new SelectBackupTransportCallback() {
            @Override
            public void onSuccess(String transportName) {
                mTransportManager.selectTransport(transportName);
                updateStateForTransport(mTransportManager.getCurrentTransportName());
                Slog.v(TAG, "Transport successfully selected: " + transport.flattenToShortString());
                try {
                    listener.onSuccess(transportName);
                } catch (RemoteException e) {
                    // Nothing to do here.
                }
            }

            @Override
            public void onFailure(int reason) {
                Slog.v(TAG, "Failed to select transport: " + transport.flattenToShortString());
                try {
                    listener.onFailure(reason);
                } catch (RemoteException e) {
                    // Nothing to do here.
                }
            }
        });

        Binder.restoreCallingIdentity(oldId);
    }

    private void updateStateForTransport(String newTransportName) {
        // Publish the name change
        Settings.Secure.putString(mContext.getContentResolver(),
                Settings.Secure.BACKUP_TRANSPORT, newTransportName);

        // And update our current-dataset bookkeeping
        IBackupTransport transport = mTransportManager.getTransportBinder(newTransportName);
        if (transport != null) {
            try {
                mCurrentToken = transport.getCurrentRestoreSet();
            } catch (Exception e) {
                // Oops.  We can't know the current dataset token, so reset and figure it out
                // when we do the next k/v backup operation on this transport.
                mCurrentToken = 0;
            }
        } else {
            // The named transport isn't bound at this particular moment, so we can't
            // know yet what its current dataset token is.  Reset as above.
            mCurrentToken = 0;
        }
    }

    // Supply the configuration Intent for the given transport.  If the name is not one
    // of the available transports, or if the transport does not supply any configuration
    // UI, the method returns null.
    @Override
    public Intent getConfigurationIntent(String transportName) {
        mContext.enforceCallingOrSelfPermission(android.Manifest.permission.BACKUP,
                "getConfigurationIntent");

        final IBackupTransport transport = mTransportManager.getTransportBinder(transportName);
        if (transport != null) {
            try {
                final Intent intent = transport.configurationIntent();
                if (MORE_DEBUG) Slog.d(TAG, "getConfigurationIntent() returning config intent "
                        + intent);
                return intent;
            } catch (Exception e) {
                /* fall through to return null */
                Slog.e(TAG, "Unable to get configuration intent from transport: " + e.getMessage());
            }
        }

        return null;
    }

    // Supply the configuration summary string for the given transport.  If the name is
    // not one of the available transports, or if the transport does not supply any
    // summary / destination string, the method can return null.
    //
    // This string is used VERBATIM as the summary text of the relevant Settings item!
    @Override
    public String getDestinationString(String transportName) {
        mContext.enforceCallingOrSelfPermission(android.Manifest.permission.BACKUP,
                "getDestinationString");

        final IBackupTransport transport = mTransportManager.getTransportBinder(transportName);
        if (transport != null) {
            try {
                final String text = transport.currentDestinationString();
                if (MORE_DEBUG) Slog.d(TAG, "getDestinationString() returning " + text);
                return text;
            } catch (Exception e) {
                /* fall through to return null */
                Slog.e(TAG, "Unable to get string from transport: " + e.getMessage());
            }
        }

        return null;
    }

    // Supply the manage-data intent for the given transport.
    @Override
    public Intent getDataManagementIntent(String transportName) {
        mContext.enforceCallingOrSelfPermission(android.Manifest.permission.BACKUP,
                "getDataManagementIntent");

        final IBackupTransport transport = mTransportManager.getTransportBinder(transportName);
        if (transport != null) {
            try {
                final Intent intent = transport.dataManagementIntent();
                if (MORE_DEBUG) Slog.d(TAG, "getDataManagementIntent() returning intent "
                        + intent);
                return intent;
            } catch (Exception e) {
                /* fall through to return null */
                Slog.e(TAG, "Unable to get management intent from transport: " + e.getMessage());
            }
        }

        return null;
    }

    // Supply the menu label for affordances that fire the manage-data intent
    // for the given transport.
    @Override
    public String getDataManagementLabel(String transportName) {
        mContext.enforceCallingOrSelfPermission(android.Manifest.permission.BACKUP,
                "getDataManagementLabel");

        final IBackupTransport transport = mTransportManager.getTransportBinder(transportName);
        if (transport != null) {
            try {
                final String text = transport.dataManagementLabel();
                if (MORE_DEBUG) Slog.d(TAG, "getDataManagementLabel() returning " + text);
                return text;
            } catch (Exception e) {
                /* fall through to return null */
                Slog.e(TAG, "Unable to get management label from transport: " + e.getMessage());
            }
        }

        return null;
    }

    // Callback: a requested backup agent has been instantiated.  This should only
    // be called from the Activity Manager.
    @Override
    public void agentConnected(String packageName, IBinder agentBinder) {
        synchronized(mAgentConnectLock) {
            if (Binder.getCallingUid() == Process.SYSTEM_UID) {
                Slog.d(TAG, "agentConnected pkg=" + packageName + " agent=" + agentBinder);
                IBackupAgent agent = IBackupAgent.Stub.asInterface(agentBinder);
                mConnectedAgent = agent;
                mConnecting = false;
            } else {
                Slog.w(TAG, "Non-system process uid=" + Binder.getCallingUid()
                        + " claiming agent connected");
            }
            mAgentConnectLock.notifyAll();
        }
    }

    // Callback: a backup agent has failed to come up, or has unexpectedly quit.
    // If the agent failed to come up in the first place, the agentBinder argument
    // will be null.  This should only be called from the Activity Manager.
    @Override
    public void agentDisconnected(String packageName) {
        // TODO: handle backup being interrupted
        synchronized(mAgentConnectLock) {
            if (Binder.getCallingUid() == Process.SYSTEM_UID) {
                mConnectedAgent = null;
                mConnecting = false;
            } else {
                Slog.w(TAG, "Non-system process uid=" + Binder.getCallingUid()
                        + " claiming agent disconnected");
            }
            mAgentConnectLock.notifyAll();
        }
    }

    // An application being installed will need a restore pass, then the Package Manager
    // will need to be told when the restore is finished.
    @Override
    public void restoreAtInstall(String packageName, int token) {
        if (Binder.getCallingUid() != Process.SYSTEM_UID) {
            Slog.w(TAG, "Non-system process uid=" + Binder.getCallingUid()
                    + " attemping install-time restore");
            return;
        }

        boolean skip = false;

        long restoreSet = getAvailableRestoreToken(packageName);
        if (DEBUG) Slog.v(TAG, "restoreAtInstall pkg=" + packageName
                + " token=" + Integer.toHexString(token)
                + " restoreSet=" + Long.toHexString(restoreSet));
        if (restoreSet == 0) {
            if (MORE_DEBUG) Slog.i(TAG, "No restore set");
            skip = true;
        }

        // Do we have a transport to fetch data for us?
        IBackupTransport transport = mTransportManager.getCurrentTransportBinder();
        if (transport == null) {
            if (DEBUG) Slog.w(TAG, "No transport");
            skip = true;
        }

        if (!mAutoRestore) {
            if (DEBUG) {
                Slog.w(TAG, "Non-restorable state: auto=" + mAutoRestore);
            }
            skip = true;
        }

        if (!skip) {
            try {
                // okay, we're going to attempt a restore of this package from this restore set.
                // The eventual message back into the Package Manager to run the post-install
                // steps for 'token' will be issued from the restore handling code.

                // This can throw and so *must* happen before the wakelock is acquired
                String dirName = transport.transportDirName();

                mWakelock.acquire();
                if (MORE_DEBUG) {
                    Slog.d(TAG, "Restore at install of " + packageName);
                }
                Message msg = mBackupHandler.obtainMessage(MSG_RUN_RESTORE);
                msg.obj = new RestoreParams(transport, dirName, null, null,
                        restoreSet, packageName, token);
                mBackupHandler.sendMessage(msg);
            } catch (Exception e) {
                // Calling into the transport broke; back off and proceed with the installation.
                Slog.e(TAG, "Unable to contact transport: " + e.getMessage());
                skip = true;
            }
        }

        if (skip) {
            // Auto-restore disabled or no way to attempt a restore; just tell the Package
            // Manager to proceed with the post-install handling for this package.
            if (DEBUG) Slog.v(TAG, "Finishing install immediately");
            try {
                mPackageManagerBinder.finishPackageInstall(token, false);
            } catch (RemoteException e) { /* can't happen */ }
        }
    }

    // Hand off a restore session
    @Override
    public IRestoreSession beginRestoreSession(String packageName, String transport) {
        if (DEBUG) Slog.v(TAG, "beginRestoreSession: pkg=" + packageName
                + " transport=" + transport);

        boolean needPermission = true;
        if (transport == null) {
            transport = mTransportManager.getCurrentTransportName();

            if (packageName != null) {
                PackageInfo app = null;
                try {
                    app = mPackageManager.getPackageInfo(packageName, 0);
                } catch (NameNotFoundException nnf) {
                    Slog.w(TAG, "Asked to restore nonexistent pkg " + packageName);
                    throw new IllegalArgumentException("Package " + packageName + " not found");
                }

                if (app.applicationInfo.uid == Binder.getCallingUid()) {
                    // So: using the current active transport, and the caller has asked
                    // that its own package will be restored.  In this narrow use case
                    // we do not require the caller to hold the permission.
                    needPermission = false;
                }
            }
        }

        if (needPermission) {
            mContext.enforceCallingOrSelfPermission(android.Manifest.permission.BACKUP,
                    "beginRestoreSession");
        } else {
            if (DEBUG) Slog.d(TAG, "restoring self on current transport; no permission needed");
        }

        synchronized(this) {
            if (mActiveRestoreSession != null) {
                Slog.i(TAG, "Restore session requested but one already active");
                return null;
            }
            if (mBackupRunning) {
                Slog.i(TAG, "Restore session requested but currently running backups");
                return null;
            }
            mActiveRestoreSession = new ActiveRestoreSession(packageName, transport);
            mBackupHandler.sendEmptyMessageDelayed(MSG_RESTORE_SESSION_TIMEOUT,
                    TIMEOUT_RESTORE_INTERVAL);
        }
        return mActiveRestoreSession;
    }

    void clearRestoreSession(ActiveRestoreSession currentSession) {
        synchronized(this) {
            if (currentSession != mActiveRestoreSession) {
                Slog.e(TAG, "ending non-current restore session");
            } else {
                if (DEBUG) Slog.v(TAG, "Clearing restore session and halting timeout");
                mActiveRestoreSession = null;
                mBackupHandler.removeMessages(MSG_RESTORE_SESSION_TIMEOUT);
            }
        }
    }

    // Note that a currently-active backup agent has notified us that it has
    // completed the given outstanding asynchronous backup/restore operation.
    @Override
    public void opComplete(int token, long result) {
        if (MORE_DEBUG) {
            Slog.v(TAG, "opComplete: " + Integer.toHexString(token) + " result=" + result);
        }
        Operation op = null;
        synchronized (mCurrentOpLock) {
            op = mCurrentOperations.get(token);
            if (op != null) {
                if (op.state == OP_TIMEOUT) {
                    // The operation already timed out, and this is a late response.  Tidy up
                    // and ignore it; we've already dealt with the timeout.
                    op = null;
                    mCurrentOperations.delete(token);
                } else if (op.state == OP_ACKNOWLEDGED) {
                    if (DEBUG) {
                        Slog.w(TAG, "Received duplicate ack for token=" +
                                Integer.toHexString(token));
                    }
                    op = null;
                    mCurrentOperations.remove(token);
                } else if (op.state == OP_PENDING) {
                    // Can't delete op from mCurrentOperations. waitUntilOperationComplete can be
                    // called after we we receive this call.
                    op.state = OP_ACKNOWLEDGED;
                }
            }
            mCurrentOpLock.notifyAll();
        }

        // The completion callback, if any, is invoked on the handler
        if (op != null && op.callback != null) {
            Pair<BackupRestoreTask, Long> callbackAndResult = Pair.create(op.callback, result);
            Message msg = mBackupHandler.obtainMessage(MSG_OP_COMPLETE, callbackAndResult);
            mBackupHandler.sendMessage(msg);
        }
    }

    @Override
    public boolean isAppEligibleForBackup(String packageName) {
        mContext.enforceCallingOrSelfPermission(android.Manifest.permission.BACKUP,
                "isAppEligibleForBackup");
        try {
            PackageInfo packageInfo = mPackageManager.getPackageInfo(packageName,
                    PackageManager.GET_SIGNATURES);
            if (!appIsEligibleForBackup(packageInfo.applicationInfo, mPackageManager) ||
                    appIsStopped(packageInfo.applicationInfo)) {
                return false;
            }
            IBackupTransport transport = mTransportManager.getCurrentTransportBinder();
            if (transport != null) {
                try {
                    return transport.isAppEligibleForBackup(packageInfo,
                        appGetsFullBackup(packageInfo));
                } catch (Exception e) {
                    Slog.e(TAG, "Unable to ask about eligibility: " + e.getMessage());
                }
            }
            // If transport is not present we couldn't tell that the package is not eligible.
            return true;
        } catch (NameNotFoundException e) {
            return false;
        }
    }

    // ----- Restore session -----

    class ActiveRestoreSession extends IRestoreSession.Stub {
        private static final String TAG = "RestoreSession";

        private String mPackageName;
        private IBackupTransport mRestoreTransport = null;
        RestoreSet[] mRestoreSets = null;
        boolean mEnded = false;
        boolean mTimedOut = false;

        ActiveRestoreSession(String packageName, String transport) {
            mPackageName = packageName;
            mRestoreTransport = mTransportManager.getTransportBinder(transport);
        }

        public void markTimedOut() {
            mTimedOut = true;
        }

        // --- Binder interface ---
        public synchronized int getAvailableRestoreSets(IRestoreObserver observer,
                IBackupManagerMonitor monitor) {
            mContext.enforceCallingOrSelfPermission(android.Manifest.permission.BACKUP,
                    "getAvailableRestoreSets");
            if (observer == null) {
                throw new IllegalArgumentException("Observer must not be null");
            }

            if (mEnded) {
                throw new IllegalStateException("Restore session already ended");
            }

            if (mTimedOut) {
                Slog.i(TAG, "Session already timed out");
                return -1;
            }

            long oldId = Binder.clearCallingIdentity();
            try {
                if (mRestoreTransport == null) {
                    Slog.w(TAG, "Null transport getting restore sets");
                    return -1;
                }

                // We know we're doing legit work now, so halt the timeout
                // until we're done.  It gets started again when the result
                // comes in.
                mBackupHandler.removeMessages(MSG_RESTORE_SESSION_TIMEOUT);

                // spin off the transport request to our service thread
                mWakelock.acquire();
                Message msg = mBackupHandler.obtainMessage(MSG_RUN_GET_RESTORE_SETS,
                        new RestoreGetSetsParams(mRestoreTransport, this, observer,
                                monitor));
                mBackupHandler.sendMessage(msg);
                return 0;
            } catch (Exception e) {
                Slog.e(TAG, "Error in getAvailableRestoreSets", e);
                return -1;
            } finally {
                Binder.restoreCallingIdentity(oldId);
            }
        }

        public synchronized int restoreAll(long token, IRestoreObserver observer,
                IBackupManagerMonitor monitor) {
            mContext.enforceCallingOrSelfPermission(android.Manifest.permission.BACKUP,
                    "performRestore");

            if (DEBUG) Slog.d(TAG, "restoreAll token=" + Long.toHexString(token)
                    + " observer=" + observer);

            if (mEnded) {
                throw new IllegalStateException("Restore session already ended");
            }

            if (mTimedOut) {
                Slog.i(TAG, "Session already timed out");
                return -1;
            }

            if (mRestoreTransport == null || mRestoreSets == null) {
                Slog.e(TAG, "Ignoring restoreAll() with no restore set");
                return -1;
            }

            if (mPackageName != null) {
                Slog.e(TAG, "Ignoring restoreAll() on single-package session");
                return -1;
            }

            String dirName;
            try {
                dirName = mRestoreTransport.transportDirName();
            } catch (Exception e) {
                // Transport went AWOL; fail.
                Slog.e(TAG, "Unable to get transport dir for restore: " + e.getMessage());
                return -1;
            }

            synchronized (mQueueLock) {
                for (int i = 0; i < mRestoreSets.length; i++) {
                    if (token == mRestoreSets[i].token) {
                        // Real work, so stop the session timeout until we finalize the restore
                        mBackupHandler.removeMessages(MSG_RESTORE_SESSION_TIMEOUT);

                        long oldId = Binder.clearCallingIdentity();
                        mWakelock.acquire();
                        if (MORE_DEBUG) {
                            Slog.d(TAG, "restoreAll() kicking off");
                        }
                        Message msg = mBackupHandler.obtainMessage(MSG_RUN_RESTORE);
                        msg.obj = new RestoreParams(mRestoreTransport, dirName,
                                observer, monitor, token);
                        mBackupHandler.sendMessage(msg);
                        Binder.restoreCallingIdentity(oldId);
                        return 0;
                    }
                }
            }

            Slog.w(TAG, "Restore token " + Long.toHexString(token) + " not found");
            return -1;
        }

        // Restores of more than a single package are treated as 'system' restores
        public synchronized int restoreSome(long token, IRestoreObserver observer,
                IBackupManagerMonitor monitor, String[] packages) {
            mContext.enforceCallingOrSelfPermission(android.Manifest.permission.BACKUP,
                    "performRestore");

            if (DEBUG) {
                StringBuilder b = new StringBuilder(128);
                b.append("restoreSome token=");
                b.append(Long.toHexString(token));
                b.append(" observer=");
                b.append(observer.toString());
                b.append(" monitor=");
                if (monitor == null) {
                    b.append("null");
                } else {
                    b.append(monitor.toString());
                }
                b.append(" packages=");
                if (packages == null) {
                    b.append("null");
                } else {
                    b.append('{');
                    boolean first = true;
                    for (String s : packages) {
                        if (!first) {
                            b.append(", ");
                        } else first = false;
                        b.append(s);
                    }
                    b.append('}');
                }
                Slog.d(TAG, b.toString());
            }

            if (mEnded) {
                throw new IllegalStateException("Restore session already ended");
            }

            if (mTimedOut) {
                Slog.i(TAG, "Session already timed out");
                return -1;
            }

            if (mRestoreTransport == null || mRestoreSets == null) {
                Slog.e(TAG, "Ignoring restoreAll() with no restore set");
                return -1;
            }

            if (mPackageName != null) {
                Slog.e(TAG, "Ignoring restoreAll() on single-package session");
                return -1;
            }

            String dirName;
            try {
                dirName = mRestoreTransport.transportDirName();
            } catch (Exception e) {
                // Transport went AWOL; fail.
                Slog.e(TAG, "Unable to get transport name for restoreSome: " + e.getMessage());
                return -1;
            }

            synchronized (mQueueLock) {
                for (int i = 0; i < mRestoreSets.length; i++) {
                    if (token == mRestoreSets[i].token) {
                        // Stop the session timeout until we finalize the restore
                        mBackupHandler.removeMessages(MSG_RESTORE_SESSION_TIMEOUT);

                        long oldId = Binder.clearCallingIdentity();
                        mWakelock.acquire();
                        if (MORE_DEBUG) {
                            Slog.d(TAG, "restoreSome() of " + packages.length + " packages");
                        }
                        Message msg = mBackupHandler.obtainMessage(MSG_RUN_RESTORE);
                        msg.obj = new RestoreParams(mRestoreTransport, dirName, observer, monitor,
                                token, packages, packages.length > 1);
                        mBackupHandler.sendMessage(msg);
                        Binder.restoreCallingIdentity(oldId);
                        return 0;
                    }
                }
            }

            Slog.w(TAG, "Restore token " + Long.toHexString(token) + " not found");
            return -1;
        }

        public synchronized int restorePackage(String packageName, IRestoreObserver observer,
                IBackupManagerMonitor monitor) {
            if (DEBUG) Slog.v(TAG, "restorePackage pkg=" + packageName + " obs=" + observer
                    + "monitor=" + monitor);

            if (mEnded) {
                throw new IllegalStateException("Restore session already ended");
            }

            if (mTimedOut) {
                Slog.i(TAG, "Session already timed out");
                return -1;
            }

            if (mPackageName != null) {
                if (! mPackageName.equals(packageName)) {
                    Slog.e(TAG, "Ignoring attempt to restore pkg=" + packageName
                            + " on session for package " + mPackageName);
                    return -1;
                }
            }

            PackageInfo app = null;
            try {
                app = mPackageManager.getPackageInfo(packageName, 0);
            } catch (NameNotFoundException nnf) {
                Slog.w(TAG, "Asked to restore nonexistent pkg " + packageName);
                return -1;
            }

            // If the caller is not privileged and is not coming from the target
            // app's uid, throw a permission exception back to the caller.
            int perm = mContext.checkPermission(android.Manifest.permission.BACKUP,
                    Binder.getCallingPid(), Binder.getCallingUid());
            if ((perm == PackageManager.PERMISSION_DENIED) &&
                    (app.applicationInfo.uid != Binder.getCallingUid())) {
                Slog.w(TAG, "restorePackage: bad packageName=" + packageName
                        + " or calling uid=" + Binder.getCallingUid());
                throw new SecurityException("No permission to restore other packages");
            }

            // So far so good; we're allowed to try to restore this package.
            long oldId = Binder.clearCallingIdentity();
            try {
                // Check whether there is data for it in the current dataset, falling back
                // to the ancestral dataset if not.
                long token = getAvailableRestoreToken(packageName);
                if (DEBUG) Slog.v(TAG, "restorePackage pkg=" + packageName
                        + " token=" + Long.toHexString(token));

                // If we didn't come up with a place to look -- no ancestral dataset and
                // the app has never been backed up from this device -- there's nothing
                // to do but return failure.
                if (token == 0) {
                    if (DEBUG) Slog.w(TAG, "No data available for this package; not restoring");
                    return -1;
                }

                String dirName;
                try {
                    dirName = mRestoreTransport.transportDirName();
                } catch (Exception e) {
                    // Transport went AWOL; fail.
                    Slog.e(TAG, "Unable to get transport dir for restorePackage: " + e.getMessage());
                    return -1;
                }

                // Stop the session timeout until we finalize the restore
                mBackupHandler.removeMessages(MSG_RESTORE_SESSION_TIMEOUT);

                // Ready to go:  enqueue the restore request and claim success
                mWakelock.acquire();
                if (MORE_DEBUG) {
                    Slog.d(TAG, "restorePackage() : " + packageName);
                }
                Message msg = mBackupHandler.obtainMessage(MSG_RUN_RESTORE);
                msg.obj = new RestoreParams(mRestoreTransport, dirName, observer, monitor,
                        token, app);
                mBackupHandler.sendMessage(msg);
            } finally {
                Binder.restoreCallingIdentity(oldId);
            }
            return 0;
        }

        // Posted to the handler to tear down a restore session in a cleanly synchronized way
        class EndRestoreRunnable implements Runnable {
            BackupManagerService mBackupManager;
            ActiveRestoreSession mSession;

            EndRestoreRunnable(BackupManagerService manager, ActiveRestoreSession session) {
                mBackupManager = manager;
                mSession = session;
            }

            public void run() {
                // clean up the session's bookkeeping
                synchronized (mSession) {
                    mSession.mRestoreTransport = null;
                    mSession.mEnded = true;
                }

                // clean up the BackupManagerImpl side of the bookkeeping
                // and cancel any pending timeout message
                mBackupManager.clearRestoreSession(mSession);
            }
        }

        public synchronized void endRestoreSession() {
            if (DEBUG) Slog.d(TAG, "endRestoreSession");

            if (mTimedOut) {
                Slog.i(TAG, "Session already timed out");
                return;
            }

            if (mEnded) {
                throw new IllegalStateException("Restore session already ended");
            }

            mBackupHandler.post(new EndRestoreRunnable(BackupManagerService.this, this));
        }
    }

    @Override
    public void dump(FileDescriptor fd, PrintWriter pw, String[] args) {
        if (!DumpUtils.checkDumpAndUsageStatsPermission(mContext, TAG, pw)) return;

        long identityToken = Binder.clearCallingIdentity();
        try {
            if (args != null) {
                for (String arg : args) {
                    if ("-h".equals(arg)) {
                        pw.println("'dumpsys backup' optional arguments:");
                        pw.println("  -h       : this help text");
                        pw.println("  a[gents] : dump information about defined backup agents");
                        return;
                    } else if ("agents".startsWith(arg)) {
                        dumpAgents(pw);
                        return;
                    }
                }
            }
            dumpInternal(pw);
        } finally {
            Binder.restoreCallingIdentity(identityToken);
        }
    }

    private void dumpAgents(PrintWriter pw) {
        List<PackageInfo> agentPackages = allAgentPackages();
        pw.println("Defined backup agents:");
        for (PackageInfo pkg : agentPackages) {
            pw.print("  ");
            pw.print(pkg.packageName); pw.println(':');
            pw.print("      "); pw.println(pkg.applicationInfo.backupAgentName);
        }
    }

    private void dumpInternal(PrintWriter pw) {
        synchronized (mQueueLock) {
            pw.println("Backup Manager is " + (mEnabled ? "enabled" : "disabled")
                    + " / " + (!mProvisioned ? "not " : "") + "provisioned / "
                    + (this.mPendingInits.size() == 0 ? "not " : "") + "pending init");
            pw.println("Auto-restore is " + (mAutoRestore ? "enabled" : "disabled"));
            if (mBackupRunning) pw.println("Backup currently running");
            pw.println("Last backup pass started: " + mLastBackupPass
                    + " (now = " + System.currentTimeMillis() + ')');
            pw.println("  next scheduled: " + KeyValueBackupJob.nextScheduled());

            pw.println("Transport whitelist:");
            for (ComponentName transport : mTransportManager.getTransportWhitelist()) {
                pw.print("    ");
                pw.println(transport.flattenToShortString());
            }

            pw.println("Available transports:");
            final String[] transports = listAllTransports();
            if (transports != null) {
                for (String t : listAllTransports()) {
                    pw.println((t.equals(mTransportManager.getCurrentTransportName()) ? "  * " : "    ") + t);
                    try {
                        IBackupTransport transport = mTransportManager.getTransportBinder(t);
                        File dir = new File(mBaseStateDir, transport.transportDirName());
                        pw.println("       destination: " + transport.currentDestinationString());
                        pw.println("       intent: " + transport.configurationIntent());
                        for (File f : dir.listFiles()) {
                            pw.println("       " + f.getName() + " - " + f.length() + " state bytes");
                        }
                    } catch (Exception e) {
                        Slog.e(TAG, "Error in transport", e);
                        pw.println("        Error: " + e);
                    }
                }
            }

            pw.println("Pending init: " + mPendingInits.size());
            for (String s : mPendingInits) {
                pw.println("    " + s);
            }

            if (DEBUG_BACKUP_TRACE) {
                synchronized (mBackupTrace) {
                    if (!mBackupTrace.isEmpty()) {
                        pw.println("Most recent backup trace:");
                        for (String s : mBackupTrace) {
                            pw.println("   " + s);
                        }
                    }
                }
            }

            pw.print("Ancestral: "); pw.println(Long.toHexString(mAncestralToken));
            pw.print("Current:   "); pw.println(Long.toHexString(mCurrentToken));

            int N = mBackupParticipants.size();
            pw.println("Participants:");
            for (int i=0; i<N; i++) {
                int uid = mBackupParticipants.keyAt(i);
                pw.print("  uid: ");
                pw.println(uid);
                HashSet<String> participants = mBackupParticipants.valueAt(i);
                for (String app: participants) {
                    pw.println("    " + app);
                }
            }

            pw.println("Ancestral packages: "
                    + (mAncestralPackages == null ? "none" : mAncestralPackages.size()));
            if (mAncestralPackages != null) {
                for (String pkg : mAncestralPackages) {
                    pw.println("    " + pkg);
                }
            }

            pw.println("Ever backed up: " + mEverStoredApps.size());
            for (String pkg : mEverStoredApps) {
                pw.println("    " + pkg);
            }

            pw.println("Pending key/value backup: " + mPendingBackups.size());
            for (BackupRequest req : mPendingBackups.values()) {
                pw.println("    " + req);
            }

            pw.println("Full backup queue:" + mFullBackupQueue.size());
            for (FullBackupEntry entry : mFullBackupQueue) {
                pw.print("    "); pw.print(entry.lastBackup);
                pw.print(" : "); pw.println(entry.packageName);
            }
        }
    }

    private static void sendBackupOnUpdate(IBackupObserver observer, String packageName,
            BackupProgress progress) {
        if (observer != null) {
            try {
                observer.onUpdate(packageName, progress);
            } catch (RemoteException e) {
                if (DEBUG) {
                    Slog.w(TAG, "Backup observer went away: onUpdate");
                }
            }
        }
    }

    private static void sendBackupOnPackageResult(IBackupObserver observer, String packageName,
            int status) {
        if (observer != null) {
            try {
                observer.onResult(packageName, status);
            } catch (RemoteException e) {
                if (DEBUG) {
                    Slog.w(TAG, "Backup observer went away: onResult");
                }
            }
        }
    }

    private static void sendBackupFinished(IBackupObserver observer, int status) {
        if (observer != null) {
            try {
                observer.backupFinished(status);
            } catch (RemoteException e) {
                if (DEBUG) {
                    Slog.w(TAG, "Backup observer went away: backupFinished");
                }
            }
        }
    }

    private Bundle putMonitoringExtra(Bundle extras, String key, String value) {
        if (extras == null) {
            extras = new Bundle();
        }
        extras.putString(key, value);
        return extras;
    }

    private Bundle putMonitoringExtra(Bundle extras, String key, int value) {
        if (extras == null) {
            extras = new Bundle();
        }
        extras.putInt(key, value);
        return extras;
    }

    private Bundle putMonitoringExtra(Bundle extras, String key, long value) {
        if (extras == null) {
            extras = new Bundle();
        }
        extras.putLong(key, value);
        return extras;
    }


    private Bundle putMonitoringExtra(Bundle extras, String key, boolean value) {
        if (extras == null) {
            extras = new Bundle();
        }
        extras.putBoolean(key, value);
        return extras;
    }

    private static IBackupManagerMonitor monitorEvent(IBackupManagerMonitor monitor, int id,
            PackageInfo pkg, int category, Bundle extras) {
        if (monitor != null) {
            try {
                Bundle bundle = new Bundle();
                bundle.putInt(BackupManagerMonitor.EXTRA_LOG_EVENT_ID, id);
                bundle.putInt(BackupManagerMonitor.EXTRA_LOG_EVENT_CATEGORY, category);
                if (pkg != null) {
                    bundle.putString(EXTRA_LOG_EVENT_PACKAGE_NAME,
                            pkg.packageName);
                    bundle.putInt(BackupManagerMonitor.EXTRA_LOG_EVENT_PACKAGE_VERSION,
                            pkg.versionCode);
                }
                if (extras != null) {
                    bundle.putAll(extras);
                }
                monitor.onEvent(bundle);
                return monitor;
            } catch(RemoteException e) {
                if (DEBUG) {
                    Slog.w(TAG, "backup manager monitor went away");
                }
            }
        }
        return null;
    }

    @Override
    public IBackupManager getBackupManagerBinder() {
        return mBackupManagerBinder;
    }

}