aaudio: steal exclusive streams
An app (B) that asks for an exclusive stream can steal
an exclusive stream from an earlier app (A).
App B will be given the MMAP resource as a SHARED stream.
The stream for app A will be disconnected and released
by the service.
If app A reopens a stream then it will get a SHARED
stream.
The order of the opening of the streams is controlled by using a
recursive_mutex in AAudioService::openStream().
Bug: 129846760
Test: media/libaaudio/tests/test_steal_exclusive.cpp
Test: also
Test: Launch AudioTroubleMaker. It should say "EXCLUSIVE".
Test: Press Home button.
Test: Siren sound from AudioTroubleMaker should continue.
Test: Launch OboeTester
Test: TEST OUTPUT, then Open, Start
Test: You should get an MMAP SHARED stream on Pixel.
Test: Go back to AudioTroubleMaker. It should say "SHARED".
Change-Id: I7f8339d8ed62546520a9b46ed398418b41ca2832
diff --git a/services/oboeservice/AAudioService.h b/services/oboeservice/AAudioService.h
index 7167868..6a2ac1f 100644
--- a/services/oboeservice/AAudioService.h
+++ b/services/oboeservice/AAudioService.h
@@ -55,6 +55,10 @@
aaudio::AAudioStreamConfiguration &configurationOutput)
override;
+ /*
+ * This is called from Binder. It checks for permissions
+ * and converts the handle passed through Binder to a stream pointer.
+ */
aaudio_result_t closeStream(aaudio::aaudio_handle_t streamHandle) override;
aaudio_result_t getStreamDescription(
@@ -84,8 +88,18 @@
aaudio_result_t stopClient(aaudio::aaudio_handle_t streamHandle,
audio_port_handle_t clientHandle) override;
+ // ===============================================================================
+ // The following public methods are only called from the service and NOT by Binder.
+ // ===============================================================================
+
aaudio_result_t disconnectStreamByPortHandle(audio_port_handle_t portHandle);
+ /*
+ * This is only called from within the Service.
+ * It bypasses the permission checks in closeStream(handle).
+ */
+ aaudio_result_t closeStream(sp<aaudio::AAudioServiceStreamBase> serviceStream);
+
private:
/** @return true if the client is the audioserver
@@ -100,8 +114,6 @@
sp<aaudio::AAudioServiceStreamBase> convertHandleToServiceStream(
aaudio::aaudio_handle_t streamHandle);
-
-
bool releaseStream(const sp<aaudio::AAudioServiceStreamBase> &serviceStream);
aaudio_result_t checkForPendingClose(const sp<aaudio::AAudioServiceStreamBase> &serviceStream,
@@ -111,6 +123,10 @@
aaudio::AAudioStreamTracker mStreamTracker;
+ // We use a lock to prevent thread A from reopening an exclusive stream
+ // after thread B steals thread A's exclusive MMAP resource stream.
+ std::recursive_mutex mOpenLock;
+
// TODO Extract the priority constants from services/audioflinger/Threads.cpp
// and share them with this code. Look for "kPriorityFastMixer".
static constexpr int32_t kRealTimeAudioPriorityClient = 2;