media.bufferpool2: Ensure uniqueness of connection id

Currently same connection id can be given to different connections if
they don't belong to the same bufferpool.

Ensure uniqueness of connection id for each connection.

Bug: 323793249
Change-Id: I350872e6d60736ea4525d473944c92b5fe3f5f84

media/bufferpool/aidl/default/Accessor.cpp

@@ -16,6 +16,8 @@
 #define LOG_TAG "AidlBufferPoolAcc"
 //#define LOG_NDEBUG 0
 
+#include <android-base/no_destructor.h>
+
 #include <sys/types.h>
 #include <stdint.h>
 #include <time.h>
@@ -41,7 +43,25 @@ static constexpr uint32_t kSeqIdVndkBit = 0;
 #endif
 
 static constexpr uint32_t kSeqIdMax = 0x7fffffff;
-uint32_t Accessor::sSeqId = time(nullptr) & kSeqIdMax;
+
+Accessor::ConnectionIdGenerator::ConnectionIdGenerator() {
+    mSeqId = static_cast<uint32_t>(time(nullptr) & kSeqIdMax);
+    mPid = static_cast<int32_t>(getpid());
+}
+
+ConnectionId Accessor::ConnectionIdGenerator::getConnectionId() {
+    uint32_t seq;
+    {
+        std::lock_guard<std::mutex> l(mLock);
+        seq = mSeqId;
+        if (mSeqId == kSeqIdMax) {
+            mSeqId = 0;
+        } else {
+            ++mSeqId;
+        }
+    }
+    return (int64_t)mPid << 32 | seq | kSeqIdVndkBit;
+}
 
 namespace {
 // anonymous namespace
@@ -239,13 +259,14 @@ BufferPoolStatus Accessor::connect(
         uint32_t *pMsgId,
         StatusDescriptor* statusDescPtr,
         InvalidationDescriptor* invDescPtr) {
+    static ::android::base::NoDestructor<ConnectionIdGenerator> sConIdGenerator;
     std::shared_ptr<Connection> newConnection = ::ndk::SharedRefBase::make<Connection>();
     BufferPoolStatus status = ResultStatus::CRITICAL_ERROR;
     {
         std::lock_guard<std::mutex> lock(mBufferPool.mMutex);
         if (newConnection) {
             int32_t pid = getpid();
-            ConnectionId id = (int64_t)pid << 32 | sSeqId | kSeqIdVndkBit;
+            ConnectionId id = sConIdGenerator->getConnectionId();
             status = mBufferPool.mObserver.open(id, statusDescPtr);
             if (status == ResultStatus::OK) {
                 newConnection->initialize(ref<Accessor>(), id);
@@ -255,11 +276,6 @@ BufferPoolStatus Accessor::connect(
                 mBufferPool.mConnectionIds.insert(id);
                 mBufferPool.mInvalidationChannel.getDesc(invDescPtr);
                 mBufferPool.mInvalidation.onConnect(id, observer);
-                if (sSeqId == kSeqIdMax) {
-                   sSeqId = 0;
-                } else {
-                    ++sSeqId;
-                }
             }
 
         }

media/bufferpool/aidl/default/Accessor.h

@@ -189,7 +189,14 @@ struct Accessor : public BnAccessor {
 private:
     // ConnectionId = pid : (timestamp_created + seqId)
     // in order to guarantee uniqueness for each connection
-    static uint32_t sSeqId;
+    struct ConnectionIdGenerator {
+        int32_t mPid;
+        uint32_t mSeqId;
+        std::mutex mLock;
+
+        ConnectionIdGenerator();
+        ConnectionId getConnectionId();
+    };
 
     const std::shared_ptr<BufferPoolAllocator> mAllocator;
     nsecs_t mScheduleEvictTs;

media/bufferpool/aidl/default/Android.bp

@@ -29,6 +29,9 @@ cc_library {
     export_include_dirs: [
         "include",
     ],
+    header_libs: [
+        "libbase_headers",
+    ],
     shared_libs: [
         "libbinder_ndk",
         "libcutils",