Consistent error checking for sp<IMemory> and pointer()

There have been concerns that an sp<IMemory> could be non-0, but the
associated pointer() still be NULL.  There are rumors this may happen
when a non-0 sp<IMemory> is passed in by client but the shared memory cannot
be re-mapped into mediaserver.

There's also evidence in the early (2009/03/03) pre-git code of checking
pointer() for NULL, after a local allocate() returned a non-0 sp<IMemory>.
It's not clear if this is "cargo cult" paranoia, or if there was a
genuine reason for the check.

In any case, we now consistently check pointer() for sp<IMemory>
input parameters in createTrack() and queueTimedBuffer().

We also check after successful allocate().  If allocate() returns a
non-0 sp<> but NULL pointer(), then treat it as if the allocate() had
returned 0.

Change-Id: I3013ac5766b493d443ecef71711ec861076a623e

1 files changed, 6 insertions, 0 deletions

diff --git a/services/audioflinger/AudioFlinger.cpp b/services/audioflinger/AudioFlinger.cpp
index c9c9f8a..5cf6ef3 100644
--- a/services/audioflinger/AudioFlinger.cpp
+++ b/services/audioflinger/AudioFlinger.cpp
@@ -476,6 +476,12 @@ sp<IAudioTrack> AudioFlinger::createTrack(
         goto Exit;
     }
 
+    if (sharedBuffer != 0 && sharedBuffer->pointer() == NULL) {
+        ALOGE("createTrack() sharedBuffer is non-0 but has NULL pointer()");
+        lStatus = BAD_VALUE;
+        goto Exit;
+    }
+
     {
         Mutex::Autolock _l(mLock);
         PlaybackThread *thread = checkPlaybackThread_l(output);