[PATCH v10 8/9] kselftest: save-and-restore errno to allow for %m formatting

[shuah]

On 7/19/19 10:42 AM, Aleksa Sarai wrote:
> Previously, using "%m" in a ksft_* format string can result in strange
> output because the errno value wasn't saved before calling other libc
> functions. The solution is to simply save and restore the errno before
> we format the user-supplied format string.
> 
> Signed-off-by: Aleksa Sarai <cyphar at cyphar.com>
> ---
>   tools/testing/selftests/kselftest.h | 15 +++++++++++++++
>   1 file changed, 15 insertions(+)
> 
> diff --git a/tools/testing/selftests/kselftest.h b/tools/testing/selftests/kselftest.h
> index ec15c4f6af55..0ac49d91a260 100644
> --- a/tools/testing/selftests/kselftest.h
> +++ b/tools/testing/selftests/kselftest.h
> @@ -10,6 +10,7 @@
>   #ifndef __KSELFTEST_H
>   #define __KSELFTEST_H
>   
> +#include <errno.h>
>   #include <stdlib.h>
>   #include <unistd.h>
>   #include <stdarg.h>
> @@ -81,58 +82,68 @@ static inline void ksft_print_cnts(void)
>   
>   static inline void ksft_print_msg(const char *msg, ...)
>   {
> +	int saved_errno = errno;
>   	va_list args;
>   
>   	va_start(args, msg);
>   	printf("# ");
> +	errno = saved_errno;
>   	vprintf(msg, args);
>   	va_end(args);
>   }
>   
>   static inline void ksft_test_result_pass(const char *msg, ...)
>   {
> +	int saved_errno = errno;
>   	va_list args;
>   
>   	ksft_cnt.ksft_pass++;
>   
>   	va_start(args, msg);
>   	printf("ok %d ", ksft_test_num());
> +	errno = saved_errno;
>   	vprintf(msg, args);
>   	va_end(args);
>   }
>   
>   static inline void ksft_test_result_fail(const char *msg, ...)
>   {
> +	int saved_errno = errno;
>   	va_list args;
>   
>   	ksft_cnt.ksft_fail++;
>   
>   	va_start(args, msg);
>   	printf("not ok %d ", ksft_test_num());
> +	errno = saved_errno;
>   	vprintf(msg, args);
>   	va_end(args);
>   }
>   
>   static inline void ksft_test_result_skip(const char *msg, ...)
>   {
> +	int saved_errno = errno;
>   	va_list args;
>   
>   	ksft_cnt.ksft_xskip++;
>   
>   	va_start(args, msg);
>   	printf("not ok %d # SKIP ", ksft_test_num());
> +	errno = saved_errno;
>   	vprintf(msg, args);
>   	va_end(args);
>   }
>   
>   static inline void ksft_test_result_error(const char *msg, ...)
>   {
> +	int saved_errno = errno;
>   	va_list args;
>   
>   	ksft_cnt.ksft_error++;
>   
>   	va_start(args, msg);
>   	printf("not ok %d # error ", ksft_test_num());
> +	errno = saved_errno;
>   	vprintf(msg, args);
>   	va_end(args);
>   }
> @@ -152,10 +163,12 @@ static inline int ksft_exit_fail(void)
>   
>   static inline int ksft_exit_fail_msg(const char *msg, ...)
>   {
> +	int saved_errno = errno;
>   	va_list args;
>   
>   	va_start(args, msg);
>   	printf("Bail out! ");
> +	errno = saved_errno;
>   	vprintf(msg, args);
>   	va_end(args);
>   
> @@ -178,10 +191,12 @@ static inline int ksft_exit_xpass(void)
>   static inline int ksft_exit_skip(const char *msg, ...)
>   {
>   	if (msg) {
> +		int saved_errno = errno;
>   		va_list args;
>   
>   		va_start(args, msg);
>   		printf("not ok %d # SKIP ", 1 + ksft_test_num());
> +		errno = saved_errno;
>   		vprintf(msg, args);
>   		va_end(args);
>   	} else {
> 

Hi Aleksa,

Can you send this patch separate from the patch series. I will apply
this as bug fix to 5.3-rc2 or rc3.

This isn't part of this series anyway and I would like to get this in
right away.

thanks,
-- Shuah