Re: Should parent's WIFSIGNALED(siginfo->si_status) be true EVENIF the SIGNAL was caught by the child?

From: Nicholas Miell
Date: Sat Sep 22 2007 - 14:58:50 EST


On Sat, 2007-09-22 at 11:22 -0700, John Z. Bohach wrote:
> Hello,
>
> It is unclear from the various documentions in the kernel and glibc what
> the proper behaviour should be for the case when a child process
> catches a SIGNAL (say for instance, SIGTERM), and then calls exit()
> from within its caught SIGNAL handler.
>
> Since the exit() will cause a SIGCHLD to the parent, and the parent
> (let's say) has a SIGCHLD sigaction (SA_SIGINFO sa_flags set), should
> the parent's WIFSIGNALED(siginfo->si_status) be true?
>
> To recap, the WIFSIGNALED section of the waitpid() manpage says:
>
> WIFSIGNALED(status)
> returns true if the child process was terminated by a signal.
>
> So the dilemna: the child caught the signal, so it wasn't terminated by
> a signal, but rather its signal handler (let's say) called exit.

POSIX says

WIFSIGNALED(stat_val)
Evaluates to a non-zero value if status was returned for a child
process that terminated due to the receipt of a signal that was
not caught (see <signal.h>).

So there's no dilemma at all and Linux is non-conformant.

--
Nicholas Miell <nmiell@xxxxxxxxxxx>

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/