Re: [PATCH 5/5] mingw: use {gm,local}time_s as backend for {gm,local}time_r

> Since Windows doesn't provide gmtime_r(3) and localtime_r(3),
> we're providing a compat version by using non-reentrant gmtime(3) and
> localtime(3) as backend. Then, we copy the returned data into the
> buffer.
>
> By doing that, in case of failure, we will dereference a NULL pointer
> returned by gmtime(3), and localtime(3), and we always return a valid
> pointer instead of NULL.
>
> Drop the memcpy(3) by using gmtime_s, and localtime_s as backend on

> Windows, and make sure we will return NULL in case of failure.
>
> Cc: Johannes Sixt <j6t@kdbg.org>
> Cc: Johannes Schindelin <Johannes.Schindelin@gmx.de>
> Signed-off-by: Doan Tran Cong Danh <congdanhqx@gmail.com>
> ---
>  compat/mingw.c | 13 +++++++------
>  1 file changed, 7 insertions(+), 6 deletions(-)
>
> diff --git a/compat/mingw.c b/compat/mingw.c
> index fe609239dd..7b21f4eee5 100644
> --- a/compat/mingw.c
> +++ b/compat/mingw.c
> @@ -1,6 +1,7 @@
>  #include "../git-compat-util.h"
>  #include "win32.h"
>  #include <conio.h>
> +#include <errno.h>
>  #include <wchar.h>
>  #include "../strbuf.h"
>  #include "../run-command.h"
> @@ -986,16 +987,16 @@ int pipe(int filedes[2])
>
>  struct tm *gmtime_r(const time_t *timep, struct tm *result)
>  {
> -	/* gmtime() in MSVCRT.DLL is thread-safe, but not reentrant */
> -	memcpy(result, gmtime(timep), sizeof(struct tm));
> -	return result;
> +	if (gmtime_s(result, timep) == 0)
> +		return result;
> +	return NULL;
>  }
>
>  struct tm *localtime_r(const time_t *timep, struct tm *result)
>  {
> -	/* localtime() in MSVCRT.DLL is thread-safe, but not reentrant */
> -	memcpy(result, localtime(timep), sizeof(struct tm));
> -	return result;
> +	if (localtime_s(result, timep) == 0)
> +		return result;
> +	return NULL;
>  }
>
>  char *mingw_getcwd(char *pointer, int len)
> --
> 2.24.0.158.gd77a74f4dd.dirty
>
>