On Tue, Sep 24, 2024 at 8:57 AM Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx> wrote:
>
> __fatal_error routine doesn't check strerror_r() return value,
> which results in the following compile time warning:
>
> posix_timers.c: In function ‘__fatal_error’:
> posix_timers.c:31:9: warning: ignoring return value of ‘strerror_r’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
> 31 | strerror_r(errno, buf, sizeof(buf));
>
> Fix this by adding a check for return value and error handling appropriate
> for the GNU-specific strerror_r() in use in __fatal_error(). Check if
> return string is null and handle accordingly.
>
> From Linux strerror_r() manual page:
>
> "The GNU-specific strerror_r() returns a pointer to a string containing
> the error message. This may be either a pointer to a string that the
> function stores in buf, or a pointer to some (immutable) static string
> (in which case buf is unused). If the function stores a string in buf,
> then at most buflen bytes are stored (the string may be truncated if
> buflen is too small and errnum is unknown). The string always includes
> a terminating null byte."
>
> Signed-off-by: Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx>
> ---
> tools/testing/selftests/timers/posix_timers.c | 12 ++++++++----
> 1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/tools/testing/selftests/timers/posix_timers.c b/tools/testing/selftests/timers/posix_timers.c
> index 16bd49492efa..ddb1cebc844e 100644
> --- a/tools/testing/selftests/timers/posix_timers.c
> +++ b/tools/testing/selftests/timers/posix_timers.c
> @@ -26,13 +26,17 @@
> static void __fatal_error(const char *test, const char *name, const char *what)
> {
> char buf[64];
> + char *ret_str = NULL;
>
> - strerror_r(errno, buf, sizeof(buf));
> + ret_str = strerror_r(errno, buf, sizeof(buf));
>
> - if (name && strlen(name))
> - ksft_exit_fail_msg("%s %s %s %s\n", test, name, what, buf);
> + if (name && strlen(name) && ret_str)
> + ksft_exit_fail_msg("%s %s %s %s\n", test, name, what, ret_str);
> + else if (ret_str)
> + ksft_exit_fail_msg("%s %s %s\n", test, what, ret_str);
> else
> - ksft_exit_fail_msg("%s %s %s\n", test, what, buf);
> + ksft_exit_fail_msg("%s %s\n", test, what);
> +
> }
Acked-by: John Stultz <jstultz@xxxxxxxxxx>
