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Commit d0309d44 authored by Austin Borger's avatar Austin Borger
Browse files

Camera / UidObserver: Add the ability to subscribe to specific UIDs 

UidObserver sends updates about the state of all packages installed on
the system. In the case of the cameraserver, we only care about a
handful of them. The current status quo is to filter out these callbacks
but there is a significant IPC cost that is not addressed by that
approach.

This patch adds new entrypoints to ActivityManagerService to listen only
to specified UIDs. This set of uids can be updated dynamically.

Change-Id: I13c35c7025496bac35dda4c8a6cf89d49c42e447
Bug: 274486653
Test: -- on physical device:
      -- testCamera2AccessCallbackInSplitMode x10
      -- ActivityManagerServiceTest
      -- ActivityManagerProcessStateTest
      -- ActivityManagerFgsBgStartTest
      -- UidObserverControllerTest
      -- Alternate focus in split screen between Camera2 + GCA x20
parent 9c65d642

services/camera/libcameraservice/CameraService.cpp

+16 −2
Original line number Diff line number Diff line
@@ -3910,18 +3910,21 @@ void CameraService::Client::OpsCallback::opChanged(int32_t op, 


void CameraService::UidPolicy::registerWithActivityManager() {

    Mutex::Autolock _l(mUidLock);

    int32_t emptyUidArray[] = { };



    if (mRegistered) return;

    status_t res = mAm.linkToDeath(this);

    mAm.registerUidObserver(this, ActivityManager::UID_OBSERVER_GONE

    mAm.registerUidObserverForUids(this, ActivityManager::UID_OBSERVER_GONE

            | ActivityManager::UID_OBSERVER_IDLE

            | ActivityManager::UID_OBSERVER_ACTIVE | ActivityManager::UID_OBSERVER_PROCSTATE

            | ActivityManager::UID_OBSERVER_PROC_OOM_ADJ,

            ActivityManager::PROCESS_STATE_UNKNOWN,

            String16("cameraserver"));

            String16("cameraserver"), emptyUidArray, 0, mObserverToken);

    if (res == OK) {

        mRegistered = true;

        ALOGV("UidPolicy: Registered with ActivityManager");

    } else {

        ALOGE("UidPolicy: Failed to register with ActivityManager: 0x%08x", res);

    }

}
@@ -4019,13 +4022,16 @@ void CameraService::UidPolicy::onUidProcAdjChanged(uid_t uid, int32_t adj) { 
            if (it->second.hasCamera) {

                for (auto &monitoredUid : mMonitoredUids) {

                    if (monitoredUid.first != uid && adj > monitoredUid.second.procAdj) {

                        ALOGV("%s: notify uid %d", __FUNCTION__, monitoredUid.first);

                        notifyUidSet.emplace(monitoredUid.first);

                    }

                }

                ALOGV("%s: notify uid %d", __FUNCTION__, uid);

                notifyUidSet.emplace(uid);

            } else {

                for (auto &monitoredUid : mMonitoredUids) {

                    if (monitoredUid.second.hasCamera && adj < monitoredUid.second.procAdj) {

                        ALOGV("%s: notify uid %d", __FUNCTION__, uid);

                        notifyUidSet.emplace(uid);

                    }

                }
@@ -4056,6 +4062,10 @@ void CameraService::UidPolicy::registerMonitorUid(uid_t uid, bool openCamera) { 
        monitoredUid.procAdj = resource_policy::UNKNOWN_ADJ;

        monitoredUid.refCount = 1;

        it = mMonitoredUids.emplace(std::pair<uid_t, MonitoredUid>(uid, monitoredUid)).first;

        status_t res = mAm.addUidToObserver(mObserverToken, String16("cameraserver"), uid);

        if (res != OK) {

            ALOGE("UidPolicy: Failed to add uid to observer: 0x%08x", res);

        }

    }



    if (openCamera) {
@@ -4073,6 +4083,10 @@ void CameraService::UidPolicy::unregisterMonitorUid(uid_t uid, bool closeCamera) 
        it->second.refCount--;

        if (it->second.refCount == 0) {

            mMonitoredUids.erase(it);

            status_t res = mAm.removeUidFromObserver(mObserverToken, String16("cameraserver"), uid);

            if (res != OK) {

                ALOGE("UidPolicy: Failed to remove uid from observer: 0x%08x", res);

            }

        } else if (closeCamera) {

            it->second.hasCamera = false;

        }

services/camera/libcameraservice/CameraService.h

+1 −0
Original line number Diff line number Diff line
@@ -798,6 +798,7 @@ private: 
        // Monitored uid map

        std::unordered_map<uid_t, MonitoredUid> mMonitoredUids;

        std::unordered_map<uid_t, bool> mOverrideUids;

        sp<IBinder> mObserverToken;

    }; // class UidPolicy



    // If sensor privacy is enabled then all apps, including those that are active, should be