glibc/sysdeps/posix/sysv_signal.c

60 lines
1.7 KiB
C

/* Copyright (C) 1991-2017 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <errno.h>
#include <signal.h>
#include <string.h> /* For the real memset prototype. */
/* Tolerate non-threads versions of Posix */
#ifndef SA_ONESHOT
#define SA_ONESHOT 0
#endif
#ifndef SA_NOMASK
#define SA_NOMASK 0
#endif
#ifndef SA_INTERRUPT
#define SA_INTERRUPT 0
#endif
/* Set the handler for the signal SIG to HANDLER,
returning the old handler, or SIG_ERR on error. */
__sighandler_t
__sysv_signal (int sig, __sighandler_t handler)
{
struct sigaction act, oact;
/* Check signal extents to protect __sigismember. */
if (handler == SIG_ERR || sig < 1 || sig >= NSIG)
{
__set_errno (EINVAL);
return SIG_ERR;
}
act.sa_handler = handler;
if (__sigemptyset (&act.sa_mask) < 0)
return SIG_ERR;
act.sa_flags = SA_ONESHOT | SA_NOMASK | SA_INTERRUPT;
act.sa_flags &= ~SA_RESTART;
if (__sigaction (sig, &act, &oact) < 0)
return SIG_ERR;
return oact.sa_handler;
}
weak_alias (__sysv_signal, sysv_signal)