camera2: Add camera client eviction enforcement.

- This updates the CameraService to implement client
  eviction behavior based on process priority.

Bug: 19186859

Change-Id: I646939b1cdf1a2237c4e5044164d55a2542cf36e

1 files changed, 14 insertions, 0 deletions

diff --git a/services/camera/libcameraservice/CameraFlashlight.cpp b/services/camera/libcameraservice/CameraFlashlight.cpp
index 8e894cd..6c237aa 100644
--- a/services/camera/libcameraservice/CameraFlashlight.cpp
+++ b/services/camera/libcameraservice/CameraFlashlight.cpp
@@ -110,6 +110,20 @@ status_t CameraFlashlight::setTorchMode(const String8& cameraId, bool enabled) {
     status_t res = OK;
     Mutex::Autolock l(mLock);
 
+    if (mOpenedCameraIds.indexOf(cameraId) != NAME_NOT_FOUND) {
+        // This case is needed to avoid state corruption during the following call sequence:
+        // CameraService::setTorchMode for camera ID 0 begins, does torch status checks
+        // CameraService::connect for camera ID 0 begins, calls prepareDeviceOpen, ends
+        // CameraService::setTorchMode for camera ID 0 continues, calls
+        //        CameraFlashlight::setTorchMode
+
+        // TODO: Move torch status checks and state updates behind this CameraFlashlight lock
+        // to avoid other similar race conditions.
+        ALOGE("%s: Camera device %s is in use, cannot set torch mode.",
+                __FUNCTION__, cameraId.string());
+        return -EBUSY;
+    }
+
     if (mFlashControl == NULL) {
         if (enabled == false) {
             return OK;