From 14e833faa0d7a4754ddc9b3ae323a3935cb50af5 Mon Sep 17 00:00:00 2001 From: Suchi Amalapurapu Date: Tue, 20 Oct 2009 11:27:32 -0700 Subject: [PATCH] If we fail to persist the current settings and fall back to the back settings file when reading settings in PackageManager, we might rename the corrupted settings to backup(in case of power failure between the earlier write failure and file deletion) and end up loosing both files. So just clear up the corrupted current settings file if we have backup. The backup wouldn't exist if everything went well with persisting the earlier settings. We do this in both read and write just in case. --- .../android/server/PackageManagerService.java | 24 ++++++++++++++----- 1 file changed, 18 insertions(+), 6 deletions(-) diff --git a/services/java/com/android/server/PackageManagerService.java b/services/java/com/android/server/PackageManagerService.java index 66e7ecda4418e..5f30b3d45b482 100644 --- a/services/java/com/android/server/PackageManagerService.java +++ b/services/java/com/android/server/PackageManagerService.java @@ -6440,12 +6440,17 @@ class PackageManagerService extends IPackageManager.Stub { // Keep the old settings around until we know the new ones have // been successfully written. if (mSettingsFilename.exists()) { - if (mBackupSettingsFilename.exists()) { - mBackupSettingsFilename.delete(); - } - if (!mSettingsFilename.renameTo(mBackupSettingsFilename)) { - Log.w(TAG, "Unable to backup package manager settings, current changes will be lost at reboot"); - return; + // Presence of backup settings file indicates that we failed + // to persist settings earlier. So preserve the older + // backup for future reference since the current settings + // might have been corrupted. + if (!mBackupSettingsFilename.exists()) { + if (!mSettingsFilename.renameTo(mBackupSettingsFilename)) { + Log.w(TAG, "Unable to backup package manager settings, current changes will be lost at reboot"); + return; + } + } else { + Log.w(TAG, "Preserving older settings backup"); } } @@ -6712,6 +6717,13 @@ class PackageManagerService extends IPackageManager.Stub { str = new FileInputStream(mBackupSettingsFilename); mReadMessages.append("Reading from backup settings file\n"); Log.i(TAG, "Reading from backup settings file!"); + if (mSettingsFilename.exists()) { + // If both the backup and settings file exist, we + // ignore the settings since it might have been + // corrupted. + Log.w(TAG, "Cleaning up settings file " + mSettingsFilename); + mSettingsFilename.delete(); + } } catch (java.io.IOException e) { // We'll try for the normal settings file. }