Re: [PATCH] maint: avoid discarded-qualifiers warnings with SELinux 3.5

[Pádraig Brady]

On 16/03/2023 23:12, Bernhard Voelker wrote:
> Since SELinux version 3.5, the return value of context_str(3) is
> declared as const; see:
>    https://github.com/SELinuxProject/selinux/commit/dd98fa322766
> Therefore, GCC complains (here with -Werror):
>    src/selinux.c: In function 'defaultcon':
>    src/selinux.c:152:16: error: assignment discards 'const' qualifier \
>      from pointer target type [-Werror=discarded-qualifiers]
>      152 |   if (!(constr = context_str (tcontext)))
>          |                ^
>    src/selinux.c: In function 'restorecon_private':
>    src/selinux.c:252:16: error: assignment discards 'const' qualifier \
>      from pointer target type [-Werror=discarded-qualifiers]
>      252 |   if (!(constr = context_str (tcontext)))
>        |                ^
>
> * src/selinux.c (defaultcon): Define CONSTR as const.
> (restorecon_private): Likewise.
> ---
>   src/selinux.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/src/selinux.c b/src/selinux.c
> index 2bd91d071..d56010bba 100644
> --- a/src/selinux.c
> +++ b/src/selinux.c
> @@ -115,7 +115,7 @@ defaultcon (struct selabel_handle *selabel_handle,
>     char *tcon = NULL;
>     context_t scontext = 0, tcontext = 0;
>     char const *contype;
> -  char *constr;
> +  char const *constr;
>     char *newpath = NULL;
>   
>     if (! IS_ABSOLUTE_FILE_NAME (path))
> @@ -183,7 +183,7 @@ restorecon_private (struct selabel_handle *selabel_handle, 
> char const *path)
>     char *tcon = NULL;
>     context_t scontext = 0, tcontext = 0;
>     char const *contype;
> -  char *constr;
> +  char const *constr;
>     int fd;
>   
>     if (!selabel_handle)

For backwards compat, do we need to use something like
the se_const wrapper we used to have?
https://github.com/coreutils/coreutils/commit/8e764584f

(eventually removed in):
https://github.com/coreutils/coreutils/commit/e53bb7ad0

cheers,
Pádraig