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Commit be11d570 authored by Greg Hackmann's avatar Greg Hackmann
Browse files

AshmemTest: test lseek() and read() on ashmem fds 



ashmem has in-kernel handlers for lseek() and read(), but they aren't
currently being tested.

Add tests for various seeks on a buffer containing holes.  If we land
inside data, then check that we read() the expected data at that offset.

Test:  /data/nativetest64/libcutils_test/libcutils_test64 \
       --gtest_filter=AshmemTest.* (on hikey)
Test:  /data/nativetest/libcutils_test/libcutils_test32 \
       --gtest_filter=AshmemTest.* (on hikey)

Bug: 37254818
Change-Id: I96135a8cea2ce99932e3bc97b5254c95ef6b264a
Signed-off-by: default avatarGreg Hackmann <ghackmann@google.com>
parent 1dcd257a

libcutils/tests/AshmemTest.cpp

+62 −4
Original line number Original line Diff line number Diff line
@@ -14,10 +14,11 @@ 
 * limitations under the License.

 * limitations under the License.

 */

 */





#include <sys/mman.h>

#include <android-base/unique_fd.h>

#include <cutils/ashmem.h>

#include <cutils/ashmem.h>

#include <gtest/gtest.h>

#include <gtest/gtest.h>

#include <android-base/unique_fd.h>

#include <linux/fs.h>

#include <sys/mman.h>





using android::base::unique_fd;

using android::base::unique_fd;
@@ -29,8 +30,8 @@ void TestCreateRegion(size_t size, unique_fd &fd, int prot) { 
    ASSERT_EQ(0, ashmem_set_prot_region(fd, prot));

    ASSERT_EQ(0, ashmem_set_prot_region(fd, prot));

}

}





void TestMmap(const unique_fd &fd, size_t size, int prot, void **region) {

void TestMmap(const unique_fd& fd, size_t size, int prot, void** region, off_t off = 0) {

    *region = mmap(nullptr, size, prot, MAP_SHARED, fd, 0);

    *region = mmap(nullptr, size, prot, MAP_SHARED, fd, off);

    ASSERT_NE(MAP_FAILED, *region);

    ASSERT_NE(MAP_FAILED, *region);

}

}
@@ -101,6 +102,63 @@ TEST(AshmemTest, ForkTest) { 
    EXPECT_EQ(0, munmap(region2, size));

    EXPECT_EQ(0, munmap(region2, size));

}

}





TEST(AshmemTest, FileOperationsTest) {

    unique_fd fd;

    void* region;



    // Allocate a 4-page buffer, but leave page-sized holes on either side

    constexpr size_t size = PAGE_SIZE * 4;

    constexpr size_t dataSize = PAGE_SIZE * 2;

    constexpr size_t holeSize = PAGE_SIZE;

    ASSERT_NO_FATAL_FAILURE(TestCreateRegion(size, fd, PROT_READ | PROT_WRITE));

    ASSERT_NO_FATAL_FAILURE(TestMmap(fd, dataSize, PROT_READ | PROT_WRITE, &region, holeSize));



    uint8_t data[dataSize];

    FillData(data, dataSize);

    memcpy(region, data, dataSize);



    constexpr off_t dataStart = holeSize;

    constexpr off_t dataEnd = dataStart + dataSize;



    // The sequence of seeks below looks something like this:

    //

    // [    ][data][data][    ]

    // --^                          lseek(99, SEEK_SET)

    //   ------^                    lseek(dataStart, SEEK_CUR)

    // ------^                      lseek(0, SEEK_DATA)

    //       ------------^          lseek(dataStart, SEEK_HOLE)

    //                      ^--     lseek(-99, SEEK_END)

    //                ^------       lseek(-dataStart, SEEK_CUR)

    const struct {

        // lseek() parameters

        off_t offset;

        int whence;

        // Expected lseek() return value

        off_t ret;

    } seeks[] = {

        {99, SEEK_SET, 99},         {dataStart, SEEK_CUR, dataStart + 99},

        {0, SEEK_DATA, dataStart},  {dataStart, SEEK_HOLE, dataEnd},

        {-99, SEEK_END, size - 99}, {-dataStart, SEEK_CUR, dataEnd - 99},

    };

    for (const auto& cfg : seeks) {

        errno = 0;

        auto off = lseek(fd, cfg.offset, cfg.whence);

        ASSERT_EQ(cfg.ret, off) << "lseek(" << cfg.offset << ", " << cfg.whence << ") failed"

                                << (errno ? ": " : "") << (errno ? strerror(errno) : "");



        if (off >= dataStart && off < dataEnd) {

            off_t dataOff = off - dataStart;

            ssize_t readSize = dataSize - dataOff;

            uint8_t buf[readSize];



            ASSERT_EQ(readSize, TEMP_FAILURE_RETRY(read(fd, buf, readSize)));

            EXPECT_EQ(0, memcmp(buf, data + dataOff, readSize));

        }

    }



    EXPECT_EQ(0, munmap(region, dataSize));

}



TEST(AshmemTest, ProtTest) {

TEST(AshmemTest, ProtTest) {

    unique_fd fd;

    unique_fd fd;

    constexpr size_t size = PAGE_SIZE;

    constexpr size_t size = PAGE_SIZE;