Check if rename of backed up file fails before persisting new changes.

If not these system services will end up with inconsistent settings files
when the device runs out of storage.
Delete mangled settings file in PackageManager if the current write fails
so that we don't end up overwriting the backed up version with the
mangled version
Include null check when retrieving fwd locked resource for an existing package

1 files changed, 11 insertions, 2 deletions

diff --git a/core/java/com/android/internal/os/BatteryStatsImpl.java b/core/java/com/android/internal/os/BatteryStatsImpl.java
index 7a8a3be..4b26b8f 100644
--- a/core/java/com/android/internal/os/BatteryStatsImpl.java
+++ b/core/java/com/android/internal/os/BatteryStatsImpl.java
@@ -2988,7 +2988,10 @@ public final class BatteryStatsImpl extends BatteryStats {
             if (mBackupFile.exists()) {
                 mBackupFile.delete();
             }
-            mFile.renameTo(mBackupFile);
+            if (!mFile.renameTo(mBackupFile)) {
+                Log.w("BatteryStats", "Failed to back up file before writing new stats");
+                return;
+            }
         }
 
         try {
@@ -3003,8 +3006,14 @@ public final class BatteryStatsImpl extends BatteryStats {
             mBackupFile.delete();
 
             mLastWriteTime = SystemClock.elapsedRealtime();
+            return;
         } catch (IOException e) {
-            Log.e("BatteryStats", "Error writing battery statistics", e);
+            Log.w("BatteryStats", "Error writing battery statistics", e);
+        }
+        if (mFile.exists()) {
+            if (!mFile.delete()) {
+                Log.w(TAG, "Failed to delete mangled file " + mFile);
+            }
         }
     }