Re: [PATCH] selftests: add binderfs selftests

[Greg KH <gregkh@linuxfoundation.org>]

On Wed, Jan 16, 2019 at 02:19:03PM +0100, Christian Brauner wrote:
> 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>
> ---
>  tools/testing/selftests/Makefile              |   1 +
>  .../selftests/filesystems/binderfs/.gitignore |   1 +
>  .../selftests/filesystems/binderfs/Makefile   |   6 +
>  .../filesystems/binderfs/binderfs_test.c      | 120 ++++++++++++++++++
>  .../selftests/filesystems/binderfs/config     |   3 +
>  5 files changed, 131 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..ca4d9b616e84
> --- /dev/null
> +++ b/tools/testing/selftests/filesystems/binderfs/binderfs_test.c
> @@ -0,0 +1,120 @@
> +// 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)
> +		ksft_exit_fail_msg("%s - Failed to mount binderfs\n",
> +				   strerror(errno));

Can you check first to see if the kernel under test really even has
binderfs in it?  If not, you need to just abort the test, not fail it,
so as to allow newer versions of kselftests to run on older kernels.

thanks,

greg k-h