Re: [PATCH] selftests: capabilities: convert error output to TAP13 ksft framework

[Shuah Khan <shuah@kernel.org>]

On 07/27/2017 12:50 PM, Andy Lutomirski wrote:
> On Wed, Jul 26, 2017 at 2:18 PM, Shuah Khan <shuahkh@osg.samsung.com> wrote:
>> Convert errx() and err() usage to appropriate TAP13 ksft API.
>>
>> Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
>> ---
>>  tools/testing/selftests/capabilities/test_execve.c | 105 ++++++++++++---------
>>  .../testing/selftests/capabilities/validate_cap.c  |   9 +-
>>  2 files changed, 65 insertions(+), 49 deletions(-)
>>
>> diff --git a/tools/testing/selftests/capabilities/test_execve.c b/tools/testing/selftests/capabilities/test_execve.c
>> index 7c38233292b0..cf6778441381 100644
>> --- a/tools/testing/selftests/capabilities/test_execve.c
>> +++ b/tools/testing/selftests/capabilities/test_execve.c
>> @@ -1,7 +1,6 @@
>>  #define _GNU_SOURCE
>>
>>  #include <cap-ng.h>
>> -#include <err.h>
>>  #include <linux/capability.h>
>>  #include <stdbool.h>
>>  #include <string.h>
>> @@ -39,29 +38,32 @@ static void vmaybe_write_file(bool enoent_ok, char *filename, char *fmt, va_list
>>         int buf_len;
>>
>>         buf_len = vsnprintf(buf, sizeof(buf), fmt, ap);
>> -       if (buf_len < 0) {
>> -               err(1, "vsnprintf failed");
>> -       }
>> -       if (buf_len >= sizeof(buf)) {
>> -               errx(1, "vsnprintf output truncated");
>> -       }
>> +       if (buf_len < 0)
>> +               ksft_exit_fail_msg("vsnprintf failed - %s\n", strerror(errno));
> 
> Could this not be a hypothetical ksft_exit_fail_msg_err or similar?
> Or a shorter name like ksft_fatal_err()?
> 
> 

Is there a reason to add _err() suffix?

ksft_exit_fail_msg() is a generic routine for a test to exit
with a test failure and print a message. The message doesn't
necessarily need to be a standard error message such as the
one err() or errx() or strerror() generate.

In some cases test could fail with a standard error condition,
but not always. In that context, it doesn't make sense to add
_err suffix. I leveraged this generic function to replace err()
and errx() usages adding strerror() not loose the important
information.

thanks,
-- Shuah