Re: [PATCH] selftests: add binderfs selftests

[Christian Brauner <christian@brauner.io>]

On January 16, 2019 6:42:20 PM GMT+02:00, Greg KH <gregkh@linuxfoundation.org> wrote:
>On Wed, Jan 16, 2019 at 06:21:12PM +0200, Christian Brauner wrote:
>> On January 16, 2019 5:54:50 PM GMT+02:00, Greg KH
><gregkh@linuxfoundation.org> wrote:
>> >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
>> 
>> Hm, I thought that's what the "config" file was for?
>> E.g. a conditional compile or is this just a hint to the
>> user what's needed to run the test?
>
>I do not know.  What happens if you try to run this test on a kernel
>without that config option?  Does it not work as the framework
>correctly
>detects this?

I did test and it worked fine but let me check by setting up a clean vm and retry.

>
>And new kernel self tests should cc: the ksefltest mailing list and the
>maintainer of that subsystem so that they can review the test for
>things
>like this.

Thanks, missed them in my Cc list.

Christian