Subject: Re: bug#73589: system* does not honor SIGINT restoration in child

From: Ludovic Courtès <[email-masked]>
Date: Sun, 20 Oct 2024 20:58:14 +0200

Hi,

Olivier Dion <[email-masked]> skribis:

> and its ouput from various executions:
>
>   1) $ ./a.out => (nil) 0x1 (nil)
>   2) $ guile -c '(system "./a.out")' => (nil) 0x1 (nil)
>   3) $ guile -c '(system* "./a.out")' => 0x1 0x1 (nil)
>
> We can see that 3) does not honor restoration of `SIGINT' to `SIG_DFL'
> like `system(3)' does.  This seems to be because of the following
> sigaction before the creation of the process:
>
> 1697  scm_dynwind_sigaction (SIGINT,
> 1698                         scm_from_uintptr_t ((uintptr_t) SIG_IGN),
> 1699                         SCM_UNDEFINED);
> 1700 #ifdef SIGQUIT
> 1701  scm_dynwind_sigaction (SIGQUIT,
> 1702                         scm_from_uintptr_t ((uintptr_t) SIG_IGN),
> 1703                         SCM_UNDEFINED);
> 1704 #endif
> 1705
> 1706  err = piped_process (&pid, prog, args,
> 1707                       SCM_UNDEFINED, SCM_UNDEFINED);

This was fixed in commit 4ae33f76d6b33ea0bedfa36050d44c88d08c2823, which
is included in 3.0.10:

--8<---------------cut here---------------start------------->8---
$ cat t.c
#include <stdio.h>
#include <signal.h>

int main(void)
{
	struct sigaction act;

	sigaction(SIGINT, NULL, &act);

	printf("%p %p %p\n", act.sa_handler, SIG_IGN, SIG_DFL);
}
$ gcc -Wall t.c
$ ./a.out 
(nil) 0x1 (nil)
$ ./meta/guile -c '(system "./a.out")'
(nil) 0x1 (nil)
$ ./meta/guile -c '(system* "./a.out")'
(nil) 0x1 (nil)
--8<---------------cut here---------------end--------------->8---

Ludo’.