Make read/write from/to XML persistent state more robust.

When writing critical state to XML an excpetion can lead to creating
a malformed XML that is later parsed and may put the device in a bad
state. Hence, on any error while writing we should bail out and drop
the partially write state on the floor.

Corollary, any error on parsing can lead to having a partially read
state that is not consistent which may lead to writing this bad state
back to disk. Hence, on any error while parsing we should bail as
our current state may be unrecoverable.

Change-Id: Ia050c16198cb583f8a51263ad2035dbb948052b8

2 files changed, 15 insertions, 8 deletions

diff --git a/packages/SettingsProvider/src/com/android/providers/settings/SettingsState.java b/packages/SettingsProvider/src/com/android/providers/settings/SettingsState.java
index c7092b386b49..0385d1eb02fd 100644
--- a/packages/SettingsProvider/src/com/android/providers/settings/SettingsState.java
+++ b/packages/SettingsProvider/src/com/android/providers/settings/SettingsState.java
@@ -383,8 +383,9 @@ final class SettingsState {
                 Slog.i(LOG_TAG, "[PERSIST END]");
             }
 
-        } catch (IOException e) {
-            Slog.wtf(LOG_TAG, "Failed to write settings, restoring backup", e);
+            // Any error while writing is fatal.
+        } catch (Throwable t) {
+            Slog.wtf(LOG_TAG, "Failed to write settings, restoring backup", t);
             destination.failWrite(out);
         } finally {
             IoUtils.closeQuietly(out);
@@ -406,9 +407,11 @@ final class SettingsState {
             XmlPullParser parser = Xml.newPullParser();
             parser.setInput(in, null);
             parseStateLocked(parser);
-        } catch (XmlPullParserException | IOException ise) {
+
+            // Any error while parsing is fatal.
+        } catch (Throwable t) {
             throw new IllegalStateException("Failed parsing settings file: "
-                    + mStatePersistFile , ise);
+                    + mStatePersistFile , t);
         } finally {
             IoUtils.closeQuietly(in);
         }
diff --git a/services/core/java/com/android/server/pm/Settings.java b/services/core/java/com/android/server/pm/Settings.java
index f3fdb0d409fd..b3aa966e37a8 100644
--- a/services/core/java/com/android/server/pm/Settings.java
+++ b/services/core/java/com/android/server/pm/Settings.java
@@ -4269,9 +4269,11 @@ final class Settings {
                 serializer.endTag(null, TAG_RUNTIME_PERMISSIONS);
                 serializer.endDocument();
                 destination.finishWrite(out);
-            } catch (IOException e) {
+
+                // Any error while writing is fatal.
+            } catch (Throwable t) {
                 Slog.wtf(PackageManagerService.TAG,
-                        "Failed to write settings, restoring backup", e);
+                        "Failed to write settings, restoring backup", t);
                 destination.failWrite(out);
             } finally {
                 IoUtils.closeQuietly(out);
@@ -4319,9 +4321,11 @@ final class Settings {
                 XmlPullParser parser = Xml.newPullParser();
                 parser.setInput(in, null);
                 parseRuntimePermissionsLPr(parser, userId);
-            } catch (XmlPullParserException | IOException ise) {
+
+                // Any error while parsing is fatal.
+            } catch (Throwable t) {
                 throw new IllegalStateException("Failed parsing permissions file: "
-                        + permissionsFile , ise);
+                        + permissionsFile , t);
             } finally {
                 IoUtils.closeQuietly(in);
             }