xref: /frameworks/base/core/java/android/app/backup/FullBackup.java

/*
 * Copyright (C) 2011 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 android.app.backup;

import android.os.ParcelFileDescriptor;
import android.util.Log;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;

import libcore.io.ErrnoException;
import libcore.io.Libcore;

/**
 * Global constant definitions et cetera related to the full-backup-to-fd
 * binary format.
 *
 * @hide
 */
public class FullBackup {
    static final String TAG = "FullBackup";

    public static final String APK_TREE_TOKEN = "a";
    public static final String OBB_TREE_TOKEN = "obb";
    public static final String ROOT_TREE_TOKEN = "r";
    public static final String DATA_TREE_TOKEN = "f";
    public static final String DATABASE_TREE_TOKEN = "db";
    public static final String SHAREDPREFS_TREE_TOKEN = "sp";
    public static final String CACHE_TREE_TOKEN = "c";
    public static final String SHARED_STORAGE_TOKEN = "shared";

    public static final String APPS_PREFIX = "apps/";
    public static final String SHARED_PREFIX = SHARED_STORAGE_TOKEN + "/";

    public static final String FULL_BACKUP_INTENT_ACTION = "fullback";
    public static final String FULL_RESTORE_INTENT_ACTION = "fullrest";
    public static final String CONF_TOKEN_INTENT_EXTRA = "conftoken";

    public static final int TYPE_EOF = 0;
    public static final int TYPE_FILE = 1;
    public static final int TYPE_DIRECTORY = 2;
    public static final int TYPE_SYMLINK = 3;

    static public native int backupToTar(String packageName, String domain,
            String linkdomain, String rootpath, String path, BackupDataOutput output);

    static public void restoreToFile(ParcelFileDescriptor data,
            long size, int type, long mode, long mtime, File outFile,
            boolean doChmod) throws IOException {
        if (type == FullBackup.TYPE_DIRECTORY) {
            // Canonically a directory has no associated content, so we don't need to read
            // anything from the pipe in this case.  Just create the directory here and
            // drop down to the final metadata adjustment.
            if (outFile != null) outFile.mkdirs();
        } else {
            FileOutputStream out = null;

            // Pull the data from the pipe, copying it to the output file, until we're done
            try {
                if (outFile != null) {
                    File parent = outFile.getParentFile();
                    if (!parent.exists()) {
                        // in practice this will only be for the default semantic directories,
                        // and using the default mode for those is appropriate.
                        // TODO: support the edge case of apps that have adjusted the
                        //       permissions on these core directories
                        parent.mkdirs();
                    }
                    out = new FileOutputStream(outFile);
                }
            } catch (IOException e) {
                Log.e(TAG, "Unable to create/open file " + outFile.getPath(), e);
            }

            byte[] buffer = new byte[32 * 1024];
            final long origSize = size;
            FileInputStream in = new FileInputStream(data.getFileDescriptor());
            while (size > 0) {
                int toRead = (size > buffer.length) ? buffer.length : (int)size;
                int got = in.read(buffer, 0, toRead);
                if (got <= 0) {
                    Log.w(TAG, "Incomplete read: expected " + size + " but got "
                            + (origSize - size));
                    break;
                }
                if (out != null) {
                    try {
                        out.write(buffer, 0, got);
                    } catch (IOException e) {
                        // Problem writing to the file.  Quit copying data and delete
                        // the file, but of course keep consuming the input stream.
                        Log.e(TAG, "Unable to write to file " + outFile.getPath(), e);
                        out.close();
                        out = null;
                        outFile.delete();
                    }
                }
                size -= got;
            }
            if (out != null) out.close();
        }

        // Now twiddle the state to match the backup, assuming all went well
        if (doChmod && outFile != null) {
            try {
                Libcore.os.chmod(outFile.getPath(), (int)mode);
            } catch (ErrnoException e) {
                e.rethrowAsIOException();
            }
            outFile.setLastModified(mtime);
        }
    }
}