[LTP] [PATCH] process_state: Enhancement of process state detection

[Petr Vorel]

Hi Li, Ian,

> The functions will be more robust against process names with
> unusual characters and will correctly read the state character
> from the /proc/[pid]/stat file. This is a necessary change
> because the process name, which is a free-form string, can
> contain spaces and other characters that would otherwise
> disrupt the simple parsing logic of the original format string.

> e.g.
>  $ cat /proc/792442/stat
>  792442 (Web Content) S 164213 4351 4351 0 -1 4194560 ...

> Reported-by: Ian Wienand <iwienand@redhat.com>
> Signed-off-by: Li Wang <liwang@redhat.com>
> Cc: Chunyu Hu <chuhu@redhat.com>
> ---
>  lib/tst_process_state.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)

> diff --git a/lib/tst_process_state.c b/lib/tst_process_state.c
> index 08a9d0966..c15283c3d 100644
> --- a/lib/tst_process_state.c
> +++ b/lib/tst_process_state.c
> @@ -22,7 +22,7 @@ int tst_process_state_wait(const char *file, const int lineno,

>  	for (;;) {
>  		safe_file_scanf(file, lineno, cleanup_fn, proc_path,
> -				"%*i %*s %c", &cur_state);
> +				"%*[^)]%*c %c", &cur_state);

Obviously correct, thanks.

Reviewed-by: Petr Vorel <pvorel@suse.cz>

But there is also the same issue in lib/tst_thread_state.c,
I guess it applies to that. Li, could you please also fix it before merge?

Also, Andrea, you added tst_thread_state_wait() and TST_THREAD_STATE_WAIT() for
futex_waitv0[23] related tests [1], but it's now not used anywhere due Jan's
changes [2] [3]. I wonder if it's still useful or whether we should remove it.

Kind regards,
Petr

[1] https://lore.kernel.org/ltp/20220209091756.17245-2-andrea.cervesato@suse.de/
[2] https://lore.kernel.org/ltp/6c5b161bc3bcf753cbda92954ca3f47cb268c68f.1663665637.git.jstancek@redhat.com/
[3] https://lore.kernel.org/ltp/6bac7035adc2cfc8ab3800fe1d2d03223ec57ff5.1663662348.git.jstancek@redhat.com/

>  		if (state == cur_state)
>  			break;
> @@ -54,7 +54,7 @@ int tst_process_state_wait2(pid_t pid, const char state)
>  			return 1;
>  		}

> -		if (fscanf(f, "%*i %*s %c", &cur_state) != 1) {
> +		if (fscanf(f, "%*[^)]%*c %c", &cur_state) != 1) {
>  			fclose(f);
>  			fprintf(stderr, "Failed to read '%s': %s\n",
>  				proc_path, strerror(errno));