This adds the promised selftest for binderfs. It will verify the following things: - binderfs mounting works - binder device allocation works - performing a binder ioctl() request through a binderfs device works - binder device removal works - binder-control removal fails - binderfs unmounting works
Cc: Todd Kjos tkjos@google.com Signed-off-by: Christian Brauner christian.brauner@ubuntu.com --- /* Changelog */
v1: - check for ENODEV on mount failure to detect whether binderfs is available If it is not, skip the test and exit with success. --- tools/testing/selftests/Makefile | 1 + .../selftests/filesystems/binderfs/.gitignore | 1 + .../selftests/filesystems/binderfs/Makefile | 6 + .../filesystems/binderfs/binderfs_test.c | 126 ++++++++++++++++++ .../selftests/filesystems/binderfs/config | 3 + 5 files changed, 137 insertions(+) create mode 100644 tools/testing/selftests/filesystems/binderfs/.gitignore create mode 100644 tools/testing/selftests/filesystems/binderfs/Makefile create mode 100644 tools/testing/selftests/filesystems/binderfs/binderfs_test.c create mode 100644 tools/testing/selftests/filesystems/binderfs/config
diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile index 1a2bd15c5b6e..400ee81a3043 100644 --- a/tools/testing/selftests/Makefile +++ b/tools/testing/selftests/Makefile @@ -10,6 +10,7 @@ TARGETS += drivers/dma-buf TARGETS += efivarfs TARGETS += exec TARGETS += filesystems +TARGETS += filesystems/binderfs TARGETS += firmware TARGETS += ftrace TARGETS += futex diff --git a/tools/testing/selftests/filesystems/binderfs/.gitignore b/tools/testing/selftests/filesystems/binderfs/.gitignore new file mode 100644 index 000000000000..8a5d9bf63dd4 --- /dev/null +++ b/tools/testing/selftests/filesystems/binderfs/.gitignore @@ -0,0 +1 @@ +binderfs_test diff --git a/tools/testing/selftests/filesystems/binderfs/Makefile b/tools/testing/selftests/filesystems/binderfs/Makefile new file mode 100644 index 000000000000..58cb659b56b4 --- /dev/null +++ b/tools/testing/selftests/filesystems/binderfs/Makefile @@ -0,0 +1,6 @@ +# SPDX-License-Identifier: GPL-2.0 + +CFLAGS += -I../../../../../usr/include/ +TEST_GEN_PROGS := binderfs_test + +include ../../lib.mk diff --git a/tools/testing/selftests/filesystems/binderfs/binderfs_test.c b/tools/testing/selftests/filesystems/binderfs/binderfs_test.c new file mode 100644 index 000000000000..34361efcb9c8 --- /dev/null +++ b/tools/testing/selftests/filesystems/binderfs/binderfs_test.c @@ -0,0 +1,126 @@ +// SPDX-License-Identifier: GPL-2.0 + +#define _GNU_SOURCE +#include <errno.h> +#include <fcntl.h> +#include <sched.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sys/ioctl.h> +#include <sys/mount.h> +#include <sys/stat.h> +#include <sys/types.h> +#include <unistd.h> +#include <linux/android/binder.h> +#include <linux/android/binderfs.h> +#include "../../kselftest.h" + +int main(int argc, char *argv[]) +{ + int fd, ret, saved_errno; + size_t len; + struct binderfs_device device = { 0 }; + struct binder_version version = { 0 }; + + ret = unshare(CLONE_NEWNS); + if (ret < 0) + ksft_exit_fail_msg("%s - Failed to unshare mount namespace\n", + strerror(errno)); + + ret = mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, 0); + if (ret < 0) + ksft_exit_fail_msg("%s - Failed to mount / as private\n", + strerror(errno)); + + ret = mkdir("/dev/binderfs", 0755); + if (ret < 0 && errno != EEXIST) + ksft_exit_fail_msg( + "%s - Failed to create binderfs mountpoint\n", + strerror(errno)); + + ret = mount(NULL, "/dev/binderfs", "binder", 0, 0); + if (ret < 0) { + if (errno != ENODEV) + ksft_exit_fail_msg("%s - Failed to mount binderfs\n", + strerror(errno)); + + ksft_test_result_skip( + "The Android binderfs filesystem is not available\n"); + ksft_exit_pass(); + } + + /* binderfs mount test passed */ + ksft_inc_pass_cnt(); + + memcpy(device.name, "my-binder", strlen("my-binder")); + + fd = open("/dev/binderfs/binder-control", O_RDONLY | O_CLOEXEC); + if (fd < 0) + ksft_exit_fail_msg( + "%s - Failed to open binder-control device\n", + strerror(errno)); + + ret = ioctl(fd, BINDER_CTL_ADD, &device); + saved_errno = errno; + close(fd); + errno = saved_errno; + if (ret < 0) + ksft_exit_fail_msg( + "%s - Failed to allocate new binder device\n", + strerror(errno)); + + printf("Allocated new binder device with major %d, minor %d, and name %s\n", + device.major, device.minor, device.name); + + /* binder device allocation test passed */ + ksft_inc_pass_cnt(); + + fd = open("/dev/binderfs/my-binder", O_CLOEXEC | O_RDONLY); + if (fd < 0) + ksft_exit_fail_msg("%s - Failed to open my-binder device\n", + strerror(errno)); + + ret = ioctl(fd, BINDER_VERSION, &version); + saved_errno = errno; + close(fd); + errno = saved_errno; + if (ret < 0) + ksft_exit_fail_msg( + "%s - Failed to open perform BINDER_VERSION request\n", + strerror(errno)); + + printf("Detected binder version: %d\n", version.protocol_version); + + /* binder transaction with binderfs binder device passed */ + ksft_inc_pass_cnt(); + + ret = unlink("/dev/binderfs/my-binder"); + if (ret < 0) + ksft_exit_fail_msg("%s - Failed to delete binder device\n", + strerror(errno)); + + /* binder device removal passed */ + ksft_inc_pass_cnt(); + + ret = unlink("/dev/binderfs/binder-control"); + if (!ret) + ksft_exit_fail_msg("Managed to delete binder-control device\n"); + else if (errno != EPERM) + ksft_exit_fail_msg( + "%s - Failed to delete binder-control device but exited with unexpected error code\n", + strerror(errno)); + + /* binder-control device removal failed as expected */ + ksft_inc_xfail_cnt(); + + ret = umount2("/dev/binderfs", MNT_DETACH); + if (ret < 0) + ksft_exit_fail_msg("%s - Failed to unmount binderfs\n", + strerror(errno)); + + /* binderfs unmount test passed */ + ksft_inc_pass_cnt(); + + ksft_exit_pass(); +} diff --git a/tools/testing/selftests/filesystems/binderfs/config b/tools/testing/selftests/filesystems/binderfs/config new file mode 100644 index 000000000000..02dd6cc9cf99 --- /dev/null +++ b/tools/testing/selftests/filesystems/binderfs/config @@ -0,0 +1,3 @@ +CONFIG_ANDROID=y +CONFIG_ANDROID_BINDERFS=y +CONFIG_ANDROID_BINDER_IPC=y
On Wed, Jan 16, 2019 at 11:27:45PM +0100, Christian Brauner wrote:
Do you have to clean up your new directory you created and the mount? Or does exiting the code here somehow undo the unshare/mount/mkdir steps above??
Same type of question for the failure paths of the mkdir and mount calls.
No cleanup? Same for other calls to ksft_exit_fail_msg() later in this file.
thanks,
greg "error handling is hard!" k-h
On Wed, Jan 16, 2019 at 11:40:50PM +0100, Greg KH wrote:
All mounts performed after a new mount namespace without propagation is setup for a process will die when all references to the mount namespace are dropped which in this case happens when the process dies.
Same comment as above. :)
The thing we might want to cleanup is the mountpoint itself "/dev/binderfs".
thanks,
greg "error handling is hard!" k-h
That's fair. With patches purely for testing I always have to force myself to pay close attention because I implicitly and very much **falsely** keep thinking that the test is less important than the actual code. And I'm always a little ashamed of that. :)
Thanks! Christian
Hi Christian,
On 1/16/19 3:27 PM, Christian Brauner wrote:
Thanks for the patch. A few comments below.
If this test requires user to be root, please add check for root uid and do a skip the test with kselftest skip code.
Use ksft_exit_skip() instead of ksft_test_result_skip()
ksft_exit_pass() would result in false pass cases. Skip is the correct exit code.
Think about other exit paths to see if skip is more appropriate.
thanks, -- Shuah
On Wed, Jan 16, 2019 at 04:11:55PM -0700, shuah wrote:
Thanks for the review!
I think in addition to privileged tests I'll also add unprivileged tests when mounting binderfs inside a user namespace so that we a) can run this test as an unprivileged user and b) test that binderfs is mountable in user namespaces.
Thanks, fixed now.
Christian
linux-kselftest-mirror@lists.linaro.org
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Christian Brauner -
Greg KH -
shuah