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: I669f27b94fb691187bb77942f53ebc02cb90ace4
Bug: 274486653
Test: -- on physical device:
      -- testCamera2AccessCallbackInSplitMode x10
      -- ActivityManagerServiceTest
      -- ActivityManagerProcessStateTest
      -- ActivityManagerFgsBgStartTest
      -- UidObserverControllerTest
      -- Alternate focus in split screen between Camera2 + GCA x20
Ignore-AOSP: Soak time in U

1 files changed, 52 insertions, 0 deletions

diff --git a/libs/binder/IActivityManager.cpp b/libs/binder/IActivityManager.cpp
index ebdaa4cc99..84900a72ff 100644
--- a/libs/binder/IActivityManager.cpp
+++ b/libs/binder/IActivityManager.cpp
@@ -77,6 +77,30 @@ public:
          return OK;
     }
 
+    virtual status_t registerUidObserverForUids(const sp<IUidObserver>& observer,
+                                                const int32_t event, const int32_t cutpoint,
+                                                const String16& callingPackage,
+                                                const int32_t uids[], size_t nUids,
+                                                /*out*/ sp<IBinder>& observerToken) {
+         Parcel data, reply;
+         data.writeInterfaceToken(IActivityManager::getInterfaceDescriptor());
+         data.writeStrongBinder(IInterface::asBinder(observer));
+         data.writeInt32(event);
+         data.writeInt32(cutpoint);
+         data.writeString16(callingPackage);
+         data.writeInt32Array(nUids, uids);
+         status_t err =
+                 remote()->transact(REGISTER_UID_OBSERVER_FOR_UIDS_TRANSACTION, data, &reply);
+         if (err != NO_ERROR || ((err = reply.readExceptionCode()) != NO_ERROR)) {
+             return err;
+         }
+         err = reply.readStrongBinder(&observerToken);
+         if (err != NO_ERROR || ((err = reply.readExceptionCode()) != NO_ERROR)) {
+             return err;
+         }
+         return OK;
+    }
+
     virtual status_t unregisterUidObserver(const sp<IUidObserver>& observer)
     {
          Parcel data, reply;
@@ -89,6 +113,34 @@ public:
          return OK;
     }
 
+    virtual status_t addUidToObserver(const sp<IBinder>& observerToken,
+                                      const String16& callingPackage, int32_t uid) {
+         Parcel data, reply;
+         data.writeInterfaceToken(IActivityManager::getInterfaceDescriptor());
+         data.writeStrongBinder(observerToken);
+         data.writeString16(callingPackage);
+         data.writeInt32(uid);
+         status_t err = remote()->transact(ADD_UID_TO_OBSERVER_TRANSACTION, data, &reply);
+         if (err != NO_ERROR || ((err = reply.readExceptionCode()) != NO_ERROR)) {
+             return err;
+         }
+         return OK;
+    }
+
+    virtual status_t removeUidFromObserver(const sp<IBinder>& observerToken,
+                                           const String16& callingPackage, int32_t uid) {
+         Parcel data, reply;
+         data.writeInterfaceToken(IActivityManager::getInterfaceDescriptor());
+         data.writeStrongBinder(observerToken);
+         data.writeString16(callingPackage);
+         data.writeInt32(uid);
+         status_t err = remote()->transact(REMOVE_UID_FROM_OBSERVER_TRANSACTION, data, &reply);
+         if (err != NO_ERROR || ((err = reply.readExceptionCode()) != NO_ERROR)) {
+             return err;
+         }
+         return OK;
+    }
+
     virtual bool isUidActive(const uid_t uid, const String16& callingPackage)
     {
          Parcel data, reply;