SystemBackupAgent.java revision 37ce3a8af6faab675319d0803b288ab1dddc76be 
1/*
2 * Copyright (C) 2009 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.android.server;
18
19
20import android.app.backup.BackupDataInput;
21import android.app.backup.BackupDataOutput;
22import android.app.backup.BackupAgentHelper;
23import android.app.backup.FullBackup;
24import android.app.backup.FullBackupDataOutput;
25import android.app.backup.WallpaperBackupHelper;
26import android.content.Context;
27import android.os.ParcelFileDescriptor;
28import android.os.ServiceManager;
29import android.util.Slog;
30
31
32import java.io.File;
33import java.io.IOException;
34
35/**
36 * Backup agent for various system-managed data, currently just the system wallpaper
37 */
38public class SystemBackupAgent extends BackupAgentHelper {
39    private static final String TAG = "SystemBackupAgent";
40
41    // These paths must match what the WallpaperManagerService uses.  The leaf *_FILENAME
42    // are also used in the full-backup file format, so must not change unless steps are
43    // taken to support the legacy backed-up datasets.
44    private static final String WALLPAPER_IMAGE_FILENAME = "wallpaper";
45    private static final String WALLPAPER_INFO_FILENAME = "wallpaper_info.xml";
46
47    // TODO: Will need to change if backing up non-primary user's wallpaper
48    private static final String WALLPAPER_IMAGE_DIR = "/data/system/users/0";
49    private static final String WALLPAPER_IMAGE = WallpaperBackupHelper.WALLPAPER_IMAGE;
50
51    // TODO: Will need to change if backing up non-primary user's wallpaper
52    private static final String WALLPAPER_INFO_DIR = "/data/system/users/0";
53    private static final String WALLPAPER_INFO = WallpaperBackupHelper.WALLPAPER_INFO;
54    // Use old keys to keep legacy data compatibility and avoid writing two wallpapers
55    private static final String WALLPAPER_IMAGE_KEY = WallpaperBackupHelper.WALLPAPER_IMAGE_KEY;
56    private static final String WALLPAPER_INFO_KEY = WallpaperBackupHelper.WALLPAPER_INFO_KEY;
57
58    @Override
59    public void onBackup(ParcelFileDescriptor oldState, BackupDataOutput data,
60            ParcelFileDescriptor newState) throws IOException {
61        // We only back up the data under the current "wallpaper" schema with metadata
62        WallpaperManagerService wallpaper = (WallpaperManagerService)ServiceManager.getService(
63                Context.WALLPAPER_SERVICE);
64        String[] files = new String[] { WALLPAPER_IMAGE, WALLPAPER_INFO };
65        String[] keys = new String[] { WALLPAPER_IMAGE_KEY, WALLPAPER_INFO_KEY };
66        if (wallpaper != null && wallpaper.getName() != null && wallpaper.getName().length() > 0) {
67            // When the wallpaper has a name, back up the info by itself.
68            // TODO: Don't rely on the innards of the service object like this!
69            // TODO: Send a delete for any stored wallpaper image in this case?
70            files = new String[] { WALLPAPER_INFO };
71            keys = new String[] { WALLPAPER_INFO_KEY };
72        }
73        addHelper("wallpaper", new WallpaperBackupHelper(SystemBackupAgent.this, files, keys));
74        super.onBackup(oldState, data, newState);
75    }
76
77    @Override
78    public void onFullBackup(FullBackupDataOutput data) throws IOException {
79        // At present we back up only the wallpaper
80        fullWallpaperBackup(data);
81    }
82
83    private void fullWallpaperBackup(FullBackupDataOutput output) {
84        // Back up the data files directly.  We do them in this specific order --
85        // info file followed by image -- because then we need take no special
86        // steps during restore; the restore will happen properly when the individual
87        // files are restored piecemeal.
88        FullBackup.backupToTar(getPackageName(), FullBackup.ROOT_TREE_TOKEN, null,
89                WALLPAPER_INFO_DIR, WALLPAPER_INFO, output.getData());
90        FullBackup.backupToTar(getPackageName(), FullBackup.ROOT_TREE_TOKEN, null,
91                WALLPAPER_IMAGE_DIR, WALLPAPER_IMAGE, output.getData());
92    }
93
94    @Override
95    public void onRestore(BackupDataInput data, int appVersionCode, ParcelFileDescriptor newState)
96            throws IOException {
97        // On restore, we also support a previous data schema "system_files"
98        addHelper("wallpaper", new WallpaperBackupHelper(SystemBackupAgent.this,
99                new String[] { WALLPAPER_IMAGE, WALLPAPER_INFO },
100                new String[] { WALLPAPER_IMAGE_KEY, WALLPAPER_INFO_KEY} ));
101        addHelper("system_files", new WallpaperBackupHelper(SystemBackupAgent.this,
102                new String[] { WALLPAPER_IMAGE },
103                new String[] { WALLPAPER_IMAGE_KEY} ));
104
105        try {
106            super.onRestore(data, appVersionCode, newState);
107
108            WallpaperManagerService wallpaper = (WallpaperManagerService)ServiceManager.getService(
109                    Context.WALLPAPER_SERVICE);
110            wallpaper.settingsRestored();
111        } catch (IOException ex) {
112            // If there was a failure, delete everything for the wallpaper, this is too aggressive,
113            // but this is hopefully a rare failure.
114            Slog.d(TAG, "restore failed", ex);
115            (new File(WALLPAPER_IMAGE)).delete();
116            (new File(WALLPAPER_INFO)).delete();
117        }
118    }
119
120    @Override
121    public void onRestoreFile(ParcelFileDescriptor data, long size,
122            int type, String domain, String path, long mode, long mtime)
123            throws IOException {
124        Slog.i(TAG, "Restoring file domain=" + domain + " path=" + path);
125
126        // Bits to indicate postprocessing we may need to perform
127        boolean restoredWallpaper = false;
128
129        File outFile = null;
130        // Various domain+files we understand a priori
131        if (domain.equals(FullBackup.ROOT_TREE_TOKEN)) {
132            if (path.equals(WALLPAPER_INFO_FILENAME)) {
133                outFile = new File(WALLPAPER_INFO);
134                restoredWallpaper = true;
135            } else if (path.equals(WALLPAPER_IMAGE_FILENAME)) {
136                outFile = new File(WALLPAPER_IMAGE);
137                restoredWallpaper = true;
138            }
139        }
140
141        try {
142            if (outFile == null) {
143                Slog.w(TAG, "Skipping unrecognized system file: [ " + domain + " : " + path + " ]");
144            }
145            FullBackup.restoreFile(data, size, type, mode, mtime, outFile);
146
147            if (restoredWallpaper) {
148                WallpaperManagerService wallpaper =
149                        (WallpaperManagerService)ServiceManager.getService(
150                        Context.WALLPAPER_SERVICE);
151                wallpaper.settingsRestored();
152            }
153        } catch (IOException e) {
154            if (restoredWallpaper) {
155                // Make sure we wind up in a good state
156                (new File(WALLPAPER_IMAGE)).delete();
157                (new File(WALLPAPER_INFO)).delete();
158            }
159        }
160    }
161}
162