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

[Jan Stancek]

On Tue, Feb 6, 2024 at 12:51 PM Petr Vorel <pvorel@suse.cz> wrote:
>
> 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>

Acked-by: Jan Stancek <jstancek@redhat.com>

>
> 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.

I'd keep it, it's a small function and someone could find useful for
some new test.

>
> 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));
>