Don't use Settings for storing the backup enable state (50f56607) · Commits · e / os / android_frameworks_base

services/backup/java/com/android/server/backup/BackupManagerService.java

+80 −6

Original line number	Diff line number	Diff line
		@@ -171,6 +171,10 @@ public class BackupManagerService {
		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).
		@@ -354,11 +358,30 @@ public class BackupManagerService {
		if (userId == UserHandle.USER_SYSTEM) {
		sInstance.initialize(userId);

		ContentResolver r = sInstance.mContext.getContentResolver();
		boolean areEnabled = Settings.Secure.getIntForUser(r,
		Settings.Secure.BACKUP_ENABLED, 0, userId) != 0;
		// Migrate legacy setting
		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");
		}
		}
		}

		try {
		sInstance.setBackupEnabled(areEnabled);
		sInstance.setBackupEnabled(readBackupEnableState(userId));
		} catch (RemoteException e) {
		// can't happen; it's a local object
		}
		@@ -9314,6 +9337,58 @@ if (MORE_DEBUG) Slog.v(TAG, " + got " + nRead + "; now wanting " + (size - soF
		}
		}

		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
		public void setBackupEnabled(boolean enable) {
		mContext.enforceCallingOrSelfPermission(android.Manifest.permission.BACKUP,
		@@ -9325,8 +9400,7 @@ if (MORE_DEBUG) Slog.v(TAG, " + got " + nRead + "; now wanting " + (size - soF
		try {
		boolean wasEnabled = mEnabled;
		synchronized (this) {
		Settings.Secure.putInt(mContext.getContentResolver(),
		Settings.Secure.BACKUP_ENABLED, enable ? 1 : 0);
		writeBackupEnableState(enable, UserHandle.USER_SYSTEM);
		mEnabled = enable;
		}