Re: [PATCH] selftests: add binderfs selftests

[Christian Brauner <christian@brauner.io>]

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?

Thanks!
Christian

Christian

 abort the test, not fail it,
>so as to allow newer versions of kselftests to run on older kernels.
>
>thanks,
>
>greg k-h