From 7eb6cfe10b1df1f9d6f4d449dff554e7fbca0362 Mon Sep 17 00:00:00 2001
From: Igor Murashkin <iam@google.com>
Date: Fri, 16 Aug 2013 14:07:11 -0700
Subject: [PATCH] Binder: Log exceptions originating from the binder stub for
 oneway calls

- Under a normal situation, if an exception happens in managed, the stack trace
  will be printed to logcat.
- Hitherto, the Binder#execTransact call silently caught exceptions and passed
  them to the remote side with Parcel#writeException
- Although this behavior might be acceptable when there is a remote side,
  for FLAG_ONEWAY calls the exception effectively disappeared.
- From the user point of view, it looked like code execution "halted" when an
  exception was thrown.

This tries to make the binder exception handling behavior more like normal,
by printing the exception to the log, to give a better indication of what
happened.

Change-Id: I1f37f0468f61e766a71db60d2fda2104936ab096
---
 core/java/android/os/Binder.java | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/core/java/android/os/Binder.java b/core/java/android/os/Binder.java
index 4627c885288c0..26fc769db5594 100644
--- a/core/java/android/os/Binder.java
+++ b/core/java/android/os/Binder.java
@@ -399,17 +399,27 @@ public class Binder implements IBinder {
         // but all that does is rewind it, and we just got these from an IPC,
         // so we'll just call it directly.
         boolean res;
+        // Log any exceptions as warnings, don't silently suppress them.
+        // If the call was FLAG_ONEWAY then these exceptions disappear into the ether.
         try {
             res = onTransact(code, data, reply, flags);
         } catch (RemoteException e) {
+            if ((flags & FLAG_ONEWAY) != 0) {
+                Log.w(TAG, "Binder call failed.", e);
+            }
             reply.setDataPosition(0);
             reply.writeException(e);
             res = true;
         } catch (RuntimeException e) {
+            if ((flags & FLAG_ONEWAY) != 0) {
+                Log.w(TAG, "Caught a RuntimeException from the binder stub implementation.", e);
+            }
             reply.setDataPosition(0);
             reply.writeException(e);
             res = true;
         } catch (OutOfMemoryError e) {
+            // Unconditionally log this, since this is generally unrecoverable.
+            Log.e(TAG, "Caught an OutOfMemoryError from the binder stub implementation.", e);
             RuntimeException re = new RuntimeException("Out of memory", e);
             reply.setDataPosition(0);
             reply.writeException(re);