Re: [PATCH 1/5] Use memset_s if possible for explicit_bzero

[Bruno Haible]

Hello Bastien,

Allow me a couple of comments, to make you more familiar with gnulib
coding conventions.

> Some OS define memset_s instead of explicit_bzero. Use it.

Indeed, FreeBSD 12 and Solaris 11.4 provide 'memset_s'.

> --- a/lib/explicit_bzero.c
> +++ b/lib/explicit_bzero.c
> @@ -25,6 +25,11 @@
>  # include <config.h>
>  #endif
>  
> +/* memset_s need this define */
> +#if HAVE_MEMSET_S
> +#define __STDC_WANT_LIB_EXT1__ 1

We prefer to write it as

   # define __STDC_WANT_LIB_EXT1__ 1

in order to highlight the number of outer #if levels.

> @@ -40,6 +45,8 @@ explicit_bzero (void *s, size_t len)
>  {
>  #ifdef HAVE_EXPLICIT_MEMSET
>    explicit_memset (s, 0, len);
> +#elif HAVE_MEMSET_S
> +  (void) memset_s(s,len,'\0',len);

Please, can you insert spaces before the opening paren and after the
commas - to go with common GNU style?

> diff --git a/m4/explicit_bzero.m4 b/m4/explicit_bzero.m4
> index 507816aff..3ca5dc771 100644
> --- a/m4/explicit_bzero.m4
> +++ b/m4/explicit_bzero.m4
> @@ -14,6 +14,11 @@ AC_DEFUN([gl_FUNC_EXPLICIT_BZERO],
>    if test $ac_cv_func_explicit_bzero = no; then
>      HAVE_EXPLICIT_BZERO=0
>    fi
> +
> +  AC_CHECK_FUNCS_ONCE([memset_s])
> +  if test $ac_cv_func_memset_s = no; then
> +    HAVE_MEMSET_S=0
> +  fi

You don't need the autoconf/shell variable HAVE_MEMSET_S (only the
preprocessor symbol HAVE_MEMSET_S). Therefore no need to set
HAVE_MEMSET_S=0.

The remaining added code, AC_CHECK_FUNCS_ONCE([memset_s]),
is only needed for the compilation of explicit_bzero.c - not
in other *.m4 files or in the module descriptions. By convention,
we put such code into the gl_PREREQ_EXPLICIT_BZERO macro.

Bruno