[LTP] [PATCH 1/1] lib: Fix fs support detection for non-root

[Cyril Hrubis <chrubis@suse.cz>]

Hi!
> grep /proc/filesystems to find kernel support.
> But consider only 0 (filesystem found) or 1 (not found),
> ignore other results (e.g. 2: /proc/filesystems not available or
> no permissions) and fallback to old solution (calling mount()).

Why is this needed?

Also this breaks FUSE detection.

> Signed-off-by: Petr Vorel <pvorel@suse.cz>
> ---
>  lib/tst_supported_fs_types.c | 19 +++++++++++++++++++
>  1 file changed, 19 insertions(+)
> 
> diff --git a/lib/tst_supported_fs_types.c b/lib/tst_supported_fs_types.c
> index 00ede549d..66307e09e 100644
> --- a/lib/tst_supported_fs_types.c
> +++ b/lib/tst_supported_fs_types.c
> @@ -52,10 +52,29 @@ static int has_kernel_support(const char *fs_type, int flags)
>  	char buf[128];
>  	int ret;
>  
> +	const char * const argv[] = { "grep", "-q", "-F", "-w", fs_type, "/proc/filesystems", NULL };
> +	ret = tst_cmd_(NULL, argv, "/dev/null", "/dev/null", TST_CMD_PASS_RETVAL);

Can't we just open the file and use fgets() in a loop?

Why do we have to execute a grep binary for something like this?

> +	if (ret == 0) {
> +		tst_res(TINFO, "Kernel supports %s", fs_type);
> +		return 1;
> +	}
> +
> +	if (ret == 1) {
> +		tst_res(TINFO, "Filesystem %s is not supported", fs_type);
> +		return 0;
> +	}
> +
>  	if (!tmpdir)
>  		tmpdir = "/tmp";
>  
>  	mount("/dev/zero", tmpdir, fs_type, 0, NULL);
> +
> +	if (errno == EPERM) {
> +		tst_res(TWARN, "No permission to detect support for %s", fs_type);
> +		return 1;

Maybe we can try to read /proc/filesystems here as a fallback?

Again why do we need this at all?

> +	}
> +
>  	if (errno != ENODEV) {
>  		tst_res(TINFO, "Kernel supports %s", fs_type);
>  		return 1;
> -- 
> 2.30.0
> 
> 
> -- 
> Mailing list info: https://lists.linux.it/listinfo/ltp

-- 
Cyril Hrubis
chrubis@suse.cz