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‘system*’ no longer changes SIGINT and SIGQUIT handlers.

Fixes <https://bugs.gnu.org/70144>.

Fixes a bug whereby ‘system*’ would change the handler of SIGINT and
SIGQUIT to SIG_IGN in a racy fashion, possibly competing with calls to
‘sigaction’ in Scheme in another thread.

This is a followup to 527c257d6e, which
witch to ‘posix_spawn’, ensuring signals are properly dealt with when
creating child processes.

* libguile/posix.c (restore_sigaction, scm_dynwind_sigaction): Remove.
(scm_system_star): Remove sigaction dynwind around call to
‘piped_process’.
* NEWS: Update.

Reported-by: Christopher Baines <mail@cbaines.net>
This commit is contained in:
Ludovic Courtès 2024-05-06 11:07:42 +02:00
parent 3b76a30e3c
commit 4ae33f76d6
No known key found for this signature in database
GPG key ID: 090B11993D9AEBB5
2 changed files with 5 additions and 35 deletions

2
NEWS
View file

@ -62,6 +62,8 @@ files. See "Random Access" in the manual for details.
** 'make-custom-port' now honors its #:conversion-strategy argument
** 'eval-string' respects #:column (previously it was set to the #:line)
** 'string->date' now allows a colon in the ISO 8601 zone offset
** 'system*' no longer fiddles with the process' signal handlers
(<https://bugs.gnu.org/70144>)
** Hashing of UTF-8 symbols with non-ASCII characters avoids corruption
(<https://bugs.gnu.org/56413>)

View file

@ -1,4 +1,4 @@
/* Copyright 1995-2014, 2016-2019, 2021-2023
/* Copyright 1995-2014, 2016-2019, 2021-2024
Free Software Foundation, Inc.
Copyright 2021 Maxime Devos <maximedevos@telenet.be>
@ -1642,27 +1642,6 @@ scm_piped_process (SCM prog, SCM args, SCM from, SCM to)
}
#undef FUNC_NAME
static void
restore_sigaction (SCM pair)
{
SCM sig, handler, flags;
sig = scm_car (pair);
handler = scm_cadr (pair);
flags = scm_cddr (pair);
scm_sigaction (sig, handler, flags);
}
static void
scm_dynwind_sigaction (int sig, SCM handler, SCM flags)
{
SCM old, scm_sig;
scm_sig = scm_from_int (sig);
old = scm_sigaction (scm_sig, handler, flags);
scm_dynwind_unwind_handler_with_scm (restore_sigaction,
scm_cons (scm_sig, old),
SCM_F_WIND_EXPLICITLY);
}
SCM_DEFINE (scm_system_star, "system*", 0, 0, 1,
(SCM args),
"Execute the command indicated by @var{args}. The first element must\n"
@ -1692,17 +1671,8 @@ SCM_DEFINE (scm_system_star, "system*", 0, 0, 1,
prog = scm_car (args);
args = scm_cdr (args);
scm_dynwind_begin (0);
/* Make sure the child can't kill us (as per normal system call). */
scm_dynwind_sigaction (SIGINT,
scm_from_uintptr_t ((uintptr_t) SIG_IGN),
SCM_UNDEFINED);
#ifdef SIGQUIT
scm_dynwind_sigaction (SIGQUIT,
scm_from_uintptr_t ((uintptr_t) SIG_IGN),
SCM_UNDEFINED);
#endif
/* Note: under the hood 'posix_spawn' takes care of blocking signals
around the call to fork and resetting handlers in the child. */
err = piped_process (&pid, prog, args,
SCM_UNDEFINED, SCM_UNDEFINED);
if (err != 0)
@ -1718,8 +1688,6 @@ SCM_DEFINE (scm_system_star, "system*", 0, 0, 1,
SCM_SYSERROR;
}
scm_dynwind_end ();
return scm_from_int (status);
}
#undef FUNC_NAME