minix/lib/libutil/raise_default_signal.c

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/* $NetBSD: raise_default_signal.c,v 1.3 2008/04/28 20:23:03 martin Exp $ */
/*-
* Copyright (c) 2007 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Luke Mewburn.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#if HAVE_NBTOOL_CONFIG_H
#include "nbtool_config.h"
#endif
#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD: raise_default_signal.c,v 1.3 2008/04/28 20:23:03 martin Exp $");
#endif
#include <errno.h>
#include <signal.h>
#include <stdio.h>
#include <string.h>
#include <util.h>
#if ! HAVE_RAISE_DEFAULT_SIGNAL
/*
* raise_default_signal sig
* Raise the default signal handler for sig, by
* - block all signals
* - set the signal handler to SIG_DFL
* - raise the signal
* - unblock the signal to deliver it
*
* The original signal mask and signal handler is restored on exit
* (whether successful or not).
*
* Returns 0 on success, or -1 on failure with errno set to
* on of the values for sigemptyset(), sigaddset(), sigprocmask(),
* sigaction(), or raise().
*/
int
raise_default_signal(int sig)
{
struct sigaction origact, act;
sigset_t origmask, fullmask, mask;
int retval, oerrno;
retval = -1;
/* Setup data structures */
/* XXX memset(3) isn't async-safe according to signal(7) */
(void)memset(&act, 0, sizeof(act));
act.sa_handler = SIG_DFL;
act.sa_flags = 0;
if ((sigemptyset(&act.sa_mask) == -1) ||
(sigfillset(&fullmask) == -1) ||
(sigemptyset(&mask) == -1) ||
(sigaddset(&mask, sig) == -1))
goto restore_none;
/* Block all signals */
if (sigprocmask(SIG_BLOCK, &fullmask, &origmask) == -1)
goto restore_none;
/* (use 'goto restore_mask' to restore state) */
/* Enable the SIG_DFL handler */
if (sigaction(sig, &act, &origact) == -1)
goto restore_mask;
/* (use 'goto restore_act' to restore state) */
/* Raise the signal, and unblock the signal to deliver it */
if ((raise(sig) == -1) ||
(sigprocmask(SIG_UNBLOCK, &mask, NULL) == -1))
goto restore_act;
/* Flag successful raise() */
retval = 0;
/* Restore the original handler */
restore_act:
oerrno = errno;
(void)sigaction(sig, &origact, NULL);
errno = oerrno;
/* Restore the original mask */
restore_mask:
oerrno = errno;
(void)sigprocmask(SIG_SETMASK, &origmask, NULL);
errno = oerrno;
restore_none:
return retval;
}
#endif /* ! HAVE_RAISE_DEFAULT_SIGNAL */