From ba0821ed3bc2536be02df1ae850619b111cbd6f4 Mon Sep 17 00:00:00 2001
From: Svet Ganov <svetoslavganov@google.com>
Date: Wed, 22 Apr 2015 13:34:31 -0700
Subject: [PATCH] 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
---
 .../android/providers/settings/SettingsState.java    | 11 +++++++----
 .../core/java/com/android/server/pm/Settings.java    | 12 ++++++++----
 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 c7092b386b496..0385d1eb02fd4 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 f3fdb0d409fdf..b3aa966e37a8c 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);
             }