Camera: Add onCameraOpened/onCameraClosed callbacks

The onCameraOpened/onCameraClosed callbacks are used to notify camera
service client with [] permission that a certain camera device has been
opened/closed.

Test: Manually check callbacks are received in SystemUI app
Bug: 150540299
Change-Id: If6f3624c43927c30afef7df0a780eafe3ae4c527
Merged-In: If6f3624c43927c30afef7df0a780eafe3ae4c527
diff --git a/camera/aidl/android/hardware/ICameraServiceListener.aidl b/camera/aidl/android/hardware/ICameraServiceListener.aidl
index e9dcbdb..47580f8 100644
--- a/camera/aidl/android/hardware/ICameraServiceListener.aidl
+++ b/camera/aidl/android/hardware/ICameraServiceListener.aidl
@@ -83,4 +83,12 @@
      * can retry after receiving this callback.
      */
     oneway void onCameraAccessPrioritiesChanged();
+
+    /**
+     * Notify registered clients about cameras being opened/closed.
+     * Only clients with android.permission.CAMERA_OPEN_CLOSE_LISTENER permission
+     * will receive such callbacks.
+     */
+    oneway void onCameraOpened(String cameraId, String clientPackageId);
+    oneway void onCameraClosed(String cameraId);
 }
diff --git a/camera/ndk/impl/ACameraManager.h b/camera/ndk/impl/ACameraManager.h
index 8c1da36..28fec82 100644
--- a/camera/ndk/impl/ACameraManager.h
+++ b/camera/ndk/impl/ACameraManager.h
@@ -92,6 +92,12 @@
         }
 
         virtual binder::Status onCameraAccessPrioritiesChanged();
+        virtual binder::Status onCameraOpened(const String16&, const String16&) {
+            return binder::Status::ok();
+        }
+        virtual binder::Status onCameraClosed(const String16&) {
+            return binder::Status::ok();
+        }
 
       private:
         const wp<CameraManagerGlobal> mCameraManager;
diff --git a/camera/tests/CameraBinderTests.cpp b/camera/tests/CameraBinderTests.cpp
index 8fe029a..dc5afc5 100644
--- a/camera/tests/CameraBinderTests.cpp
+++ b/camera/tests/CameraBinderTests.cpp
@@ -95,6 +95,17 @@
         return binder::Status::ok();
     }
 
+    virtual binder::Status onCameraOpened(const String16& /*cameraId*/,
+            const String16& /*clientPackageName*/) {
+        // No op
+        return binder::Status::ok();
+    }
+
+    virtual binder::Status onCameraClosed(const String16& /*cameraId*/) {
+        // No op
+        return binder::Status::ok();
+    }
+
     bool waitForNumCameras(size_t num) const {
         Mutex::Autolock l(mLock);
 
diff --git a/services/camera/libcameraservice/CameraService.cpp b/services/camera/libcameraservice/CameraService.cpp
index b20c9a4..670e026 100644
--- a/services/camera/libcameraservice/CameraService.cpp
+++ b/services/camera/libcameraservice/CameraService.cpp
@@ -118,6 +118,8 @@
 // ----------------------------------------------------------------------------
 
 static const String16 sManageCameraPermission("android.permission.MANAGE_CAMERA");
+static const String16 sCameraOpenCloseListenerPermission(
+        "android.permission.CAMERA_OPEN_CLOSE_LISTENER");
 
 // Matches with PERCEPTIBLE_APP_ADJ in ProcessList.java
 static constexpr int32_t kVendorClientScore = 200;
@@ -1811,7 +1813,11 @@
         }
 
         auto clientUid = CameraThreadState::getCallingUid();
-        sp<ServiceListener> serviceListener = new ServiceListener(this, listener, clientUid);
+        auto clientPid = CameraThreadState::getCallingPid();
+        bool openCloseCallbackAllowed = checkPermission(sCameraOpenCloseListenerPermission,
+                clientPid, clientUid);
+        sp<ServiceListener> serviceListener = new ServiceListener(this, listener,
+                clientUid, clientPid, openCloseCallbackAllowed);
         auto ret = serviceListener->initialize();
         if (ret != NO_ERROR) {
             String8 msg = String8::format("Failed to initialize service listener: %s (%d)",
@@ -2515,6 +2521,9 @@
 
     sCameraService->mUidPolicy->registerMonitorUid(mClientUid);
 
+    // Notify listeners of camera open/close status
+    sCameraService->updateOpenCloseStatus(mCameraIdStr, true/*open*/, mClientPackageName);
+
     return OK;
 }
 
@@ -2555,6 +2564,9 @@
 
     sCameraService->mUidPolicy->unregisterMonitorUid(mClientUid);
 
+    // Notify listeners of camera open/close status
+    sCameraService->updateOpenCloseStatus(mCameraIdStr, false/*open*/, mClientPackageName);
+
     return OK;
 }
 
@@ -3311,6 +3323,29 @@
         });
 }
 
+void CameraService::updateOpenCloseStatus(const String8& cameraId, bool open,
+        const String16& clientPackageName) {
+    Mutex::Autolock lock(mStatusListenerLock);
+
+    for (const auto& it : mListenerList) {
+        if (!it.second->isOpenCloseCallbackAllowed()) {
+            continue;
+        }
+
+        binder::Status ret;
+        String16 cameraId64(cameraId);
+        if (open) {
+            ret = it.second->getListener()->onCameraOpened(cameraId64, clientPackageName);
+        } else {
+            ret = it.second->getListener()->onCameraClosed(cameraId64);
+        }
+        if (!ret.isOk()) {
+            ALOGE("%s: Failed to trigger onCameraOpened/onCameraClosed callback: %d", __FUNCTION__,
+                    ret.exceptionCode());
+        }
+    }
+}
+
 template<class Func>
 void CameraService::CameraState::updateStatus(StatusInternal status,
         const String8& cameraId,
diff --git a/services/camera/libcameraservice/CameraService.h b/services/camera/libcameraservice/CameraService.h
index 22842a1..bcaca9f 100644
--- a/services/camera/libcameraservice/CameraService.h
+++ b/services/camera/libcameraservice/CameraService.h
@@ -817,7 +817,9 @@
     class ServiceListener : public virtual IBinder::DeathRecipient {
         public:
             ServiceListener(sp<CameraService> parent, sp<hardware::ICameraServiceListener> listener,
-                    int uid) : mParent(parent), mListener(listener), mListenerUid(uid) {}
+                    int uid, int pid, bool openCloseCallbackAllowed) : mParent(parent),
+                    mListener(listener), mListenerUid(uid), mListenerPid(pid),
+                    mOpenCloseCallbackAllowed(openCloseCallbackAllowed) {}
 
             status_t initialize() {
                 return IInterface::asBinder(mListener)->linkToDeath(this);
@@ -831,12 +833,16 @@
             }
 
             int getListenerUid() { return mListenerUid; }
+            int getListenerPid() { return mListenerPid; }
             sp<hardware::ICameraServiceListener> getListener() { return mListener; }
+            bool isOpenCloseCallbackAllowed() { return mOpenCloseCallbackAllowed; }
 
         private:
             wp<CameraService> mParent;
             sp<hardware::ICameraServiceListener> mListener;
             int mListenerUid;
+            int mListenerPid;
+            bool mOpenCloseCallbackAllowed = false;
     };
 
     // Guarded by mStatusListenerMutex
@@ -859,6 +865,13 @@
     void updateStatus(StatusInternal status,
             const String8& cameraId);
 
+    /**
+     * Update the opened/closed status of the given camera id.
+     *
+     * This method acqiures mStatusListenerLock.
+     */
+    void updateOpenCloseStatus(const String8& cameraId, bool open, const String16& packageName);
+
     // flashlight control
     sp<CameraFlashlight> mFlashlight;
     // guard mTorchStatusMap
diff --git a/services/camera/libcameraservice/hidl/AidlCameraServiceListener.h b/services/camera/libcameraservice/hidl/AidlCameraServiceListener.h
index 0f6be79..b9e5857 100644
--- a/services/camera/libcameraservice/hidl/AidlCameraServiceListener.h
+++ b/services/camera/libcameraservice/hidl/AidlCameraServiceListener.h
@@ -54,6 +54,15 @@
         // TODO: no implementation yet.
         return binder::Status::ok();
     }
+    virtual binder::Status onCameraOpened(const ::android::String16& /*cameraId*/,
+            const ::android::String16& /*clientPackageId*/) {
+        // empty implementation
+        return binder::Status::ok();
+    }
+    virtual binder::Status onCameraClosed(const ::android::String16& /*cameraId*/) {
+        // empty implementation
+        return binder::Status::ok();
+    }
 };
 
 } // implementation