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Commit fc700a03 authored by Ytai Ben-Tsvi's avatar Ytai Ben-Tsvi
Browse files

Add support for read-only SharedFileRegion 

A receiver of a SharedFileRegion needs to know whether it is allowed
to write into it. Added a flag in the AIDL file to indicate that and
made this compatible with the READ_ONLY flag of IMemoryHeap.

Test: atest shmemTest
Change-Id: I3f26a36e152c2e9bf3aac4ff7f0067f9242b565b
parent d5aa6164

media/libshmem/ShmemCompat.cpp

+4 −1
Original line number Diff line number Diff line
@@ -49,8 +49,10 @@ bool convertSharedFileRegionToIMemory(const SharedFileRegion& shmem, 
        return false;

    }



    uint32_t flags = !shmem.writeable ? IMemoryHeap::READ_ONLY : 0;



    const sp<MemoryHeapBase> heap =

            new MemoryHeapBase(shmem.fd.get(), heapSize, 0, heapStartOffset);

            new MemoryHeapBase(shmem.fd.get(), heapSize, flags, heapStartOffset);

    *result = sp<MemoryBase>::make(heap,

                                   shmem.offset - heapStartOffset,

                                   shmem.size);
@@ -89,6 +91,7 @@ bool convertIMemoryToSharedFileRegion(const sp<IMemory>& mem, 
        result->fd.reset(base::unique_fd(fd));

        result->size = size;

        result->offset = heap->getOffset() + offset;

        result->writeable = (heap->getFlags() & IMemoryHeap::READ_ONLY) == 0;

    }

    return true;

}

media/libshmem/ShmemTest.cpp

+25 −2
Original line number Diff line number Diff line
@@ -44,10 +44,11 @@ SharedFileRegion makeInvalidSharedFileRegion(int64_t offset, int64_t size) { 
    return shmem;

}



sp<IMemory> makeIMemory(const std::vector<uint8_t>& content) {

sp<IMemory> makeIMemory(const std::vector<uint8_t>& content, bool writeable = true) {

    constexpr size_t kOffset = 19;



    sp<MemoryHeapBase> heap = new MemoryHeapBase(content.size());

    sp<MemoryHeapBase> heap = new MemoryHeapBase(content.size(),

                                                 !writeable ? IMemoryHeap::READ_ONLY : 0);

    sp<IMemory> result = sp<MemoryBase>::make(heap, kOffset, content.size());

    memcpy(result->unsecurePointer(), content.data(), content.size());

    return result;
@@ -69,9 +70,31 @@ TEST(ShmemTest, Conversion) { 
        ASSERT_TRUE(convertIMemoryToSharedFileRegion(imem, &shmem));

        ASSERT_EQ(3, shmem.size);

        ASSERT_GE(shmem.fd.get(), 0);

        ASSERT_TRUE(shmem.writeable);

        ASSERT_TRUE(convertSharedFileRegionToIMemory(shmem, &reconstructed));

    }

    ASSERT_EQ(3, reconstructed->size());

    ASSERT_EQ(reconstructed->getMemory()->getFlags() & IMemoryHeap::READ_ONLY,  0);

    const uint8_t* p =

            reinterpret_cast<const uint8_t*>(reconstructed->unsecurePointer());

    EXPECT_EQ(6, p[0]);

    EXPECT_EQ(5, p[1]);

    EXPECT_EQ(3, p[2]);

}



TEST(ShmemTest, ConversionReadOnly) {

    sp<IMemory> reconstructed;

    {

        SharedFileRegion shmem;

        sp<IMemory> imem = makeIMemory({6, 5, 3}, false);

        ASSERT_TRUE(convertIMemoryToSharedFileRegion(imem, &shmem));

        ASSERT_EQ(3, shmem.size);

        ASSERT_GE(shmem.fd.get(), 0);

        ASSERT_FALSE(shmem.writeable);

        ASSERT_TRUE(convertSharedFileRegionToIMemory(shmem, &reconstructed));

    }

    ASSERT_EQ(3, reconstructed->size());

    ASSERT_NE(reconstructed->getMemory()->getFlags() & IMemoryHeap::READ_ONLY,  0);

    const uint8_t* p =

            reinterpret_cast<const uint8_t*>(reconstructed->unsecurePointer());

    EXPECT_EQ(6, p[0]);

media/libshmem/aidl/android/media/SharedFileRegion.aidl

+2 −0
Original line number Diff line number Diff line
@@ -34,4 +34,6 @@ parcelable SharedFileRegion { 
    long offset;

    /** Size, in bytes of the memory region. Must be non-negative. */

    long size;

    /** Whether the region is writeable. */

    boolean writeable;

}