From 50d2573a1ca7095c8c6c6a708f35fcfce94e4972 Mon Sep 17 00:00:00 2001
From: Pawin Vongmasa <pawin@google.com>
Date: Fri, 24 Apr 2020 18:59:54 -0700
Subject: [PATCH] BufferPool: Guarantee double-loadability

When a library is double loadable, there may be 2 singleton objects in
the same process. Using the pid as an identifier is not sufficient. This
CL adds a bit to the identifier based on which side the library is
loaded.

Test: atest CtsMediaTestCases -- \
--module-arg CtsMediaTestCases:size:small

Bug: 147147992
Change-Id: If3b52e4491ced58ee71bb55f0fc4c3c17569c0f3
---
 media/bufferpool/2.0/AccessorImpl.cpp | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/media/bufferpool/2.0/AccessorImpl.cpp b/media/bufferpool/2.0/AccessorImpl.cpp
index 194765637c..cb55b0781d 100644
--- a/media/bufferpool/2.0/AccessorImpl.cpp
+++ b/media/bufferpool/2.0/AccessorImpl.cpp
@@ -135,7 +135,14 @@ bool contains(std::map<T, std::set<U>> *mapOfSet, T key, U value) {
     return false;
 }
 
-uint32_t Accessor::Impl::sSeqId = time(nullptr);
+#ifdef __ANDROID_VNDK__
+static constexpr uint32_t kSeqIdVndkBit = 1 << 31;
+#else
+static constexpr uint32_t kSeqIdVndkBit = 0;
+#endif
+
+static constexpr uint32_t kSeqIdMax = 0x7fffffff;
+uint32_t Accessor::Impl::sSeqId = time(nullptr) & kSeqIdMax;
 
 Accessor::Impl::Impl(
         const std::shared_ptr<BufferPoolAllocator> &allocator)
@@ -157,7 +164,7 @@ ResultStatus Accessor::Impl::connect(
         std::lock_guard<std::mutex> lock(mBufferPool.mMutex);
         if (newConnection) {
             int32_t pid = getpid();
-            ConnectionId id = (int64_t)pid << 32 | sSeqId;
+            ConnectionId id = (int64_t)pid << 32 | sSeqId | kSeqIdVndkBit;
             status = mBufferPool.mObserver.open(id, statusDescPtr);
             if (status == ResultStatus::OK) {
                 newConnection->initialize(accessor, id);
@@ -167,7 +174,7 @@ ResultStatus Accessor::Impl::connect(
                 mBufferPool.mConnectionIds.insert(id);
                 mBufferPool.mInvalidationChannel.getDesc(invDescPtr);
                 mBufferPool.mInvalidation.onConnect(id, observer);
-                if (sSeqId == UINT32_MAX) {
+                if (sSeqId == kSeqIdMax) {
                    sSeqId = 0;
                 } else {
                     ++sSeqId;