Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 86c1d552 authored by Isaac J. Manjarres's avatar Isaac J. Manjarres
Browse files

ashmem_test: Cleanup and document fork tests 



The tests that fork a child process and have the child process update
use ASSERT_EXIT() to fork and wait for the child process to terminate.
However, from looking at the code at a first pass, that is not entirely
obvious.

Therefore, document the fork tests and simplify some of the logic in
the tests.

No functional change.

Bug: 111903542
Change-Id: Iac923ccad9cea0fc7d823c6e2c46c47fbf6c0282
Signed-off-by: default avatarIsaac J. Manjarres <isaacmanjarres@google.com>
parent f7ba46ae

libcutils/ashmem_test.cpp

+25 −3
Original line number Diff line number Diff line
@@ -84,6 +84,11 @@ TEST(AshmemTest, ForkTest) { 
    ASSERT_EQ(0, memcmp(region1, data.data(), size));

    EXPECT_EQ(0, munmap(region1, size));



    // This part of the test forks a separate process via ASSERT_EXIT() and

    // clears the ashmem buffer.

    //

    // This is to ensure that updates to the contents of the buffer are visible

    // across processes with a reference to the buffer.

    ASSERT_EXIT(

        {

            if (!ashmem_valid(fd)) {
@@ -206,15 +211,25 @@ TEST(AshmemTest, ForkProtTest) { 
    int protFlags[] = { PROT_READ, PROT_WRITE };

    for (size_t i = 0; i < arraysize(protFlags); i++) {

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



        // This part of the test forks a process via ASSERT_EXIT()

        // and has the child process change the mapping permissions of the

        // buffer.

        //

        // The intent of this is to ensure that updates to the buffer's

        // mapping permissions are visible across processes that reference the

        // buffer.

        //

        // In this case, the parent process attempts to map the buffer with a

        // permission that is denied, which should fail.

        ASSERT_EXIT(

            {

                if (!ashmem_valid(fd)) {

                    _exit(3);

                } else if (ashmem_set_prot_region(fd, protFlags[i]) >= 0) {

                    _exit(0);

                } else {

                } else if (ashmem_set_prot_region(fd, protFlags[i]) == -1) {

                    _exit(1);

                }

                _exit(0);

            },

            ::testing::ExitedWithCode(0), "");

        ASSERT_NO_FATAL_FAILURE(TestProtDenied(fd, size, protFlags[1-i]));
@@ -237,6 +252,13 @@ TEST(AshmemTest, ForkMultiRegionTest) { 
        EXPECT_EQ(0, munmap(region, size));

    }



    // This part of the test creates a child process via ASSERT_EXIT()

    // that clears each of the ashmem buffers that were created earlier.

    //

    // The intent of this is for the parent process to check each region to make

    // sure that the updates from the child process are visible, thereby showing

    // that updates across multiple shared buffers are visible across multiple

    // processes.

    ASSERT_EXIT({

        for (int i = 0; i < nRegions; i++) {

            if (!ashmem_valid(fd[i])) {