libplatform-177.200.16.tar.gz

[apple/libplatform.git] / src / setjmp / generic / sigaction.c

/*
 * Copyright (c) 1999-2017 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this
 * file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/*
 * Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved
 *
 *	@(#)sigaction.c	1.0
 */

#include <stdlib.h>
#include <unistd.h>
#include <signal.h>
#include <sys/signal.h>
#include <errno.h>

// keep in sync with BSD_KERNEL_PRIVATE value in xnu/bsd/sys/signal.h
#define SA_VALIDATE_SIGRETURN_FROM_SIGTRAMP 0x0400

/*
 *	Intercept the sigaction syscall and use our signal trampoline
 *	as the signal handler instead.  The code here is derived
 *	from sigvec in sys/kern_sig.c.
 */
extern int __sigaction (int, struct __sigaction * __restrict,
		struct sigaction * __restrict);

int
__platform_sigaction (int sig, const struct sigaction * __restrict nsv,
		struct sigaction * __restrict osv)
{
	extern void _sigtramp();
	struct __sigaction sa;
	struct __sigaction *sap;
	int ret;

	if (sig <= 0 || sig >= NSIG || sig == SIGKILL || sig == SIGSTOP) {
	        errno = EINVAL;
	        return (-1);
	}
	sap = (struct __sigaction *)0;
	if (nsv) {
		sa.sa_handler = nsv->sa_handler;
		sa.sa_tramp = _sigtramp;
		sa.sa_mask = nsv->sa_mask;
		sa.sa_flags = nsv->sa_flags | SA_VALIDATE_SIGRETURN_FROM_SIGTRAMP;
		sap = &sa;
	}
	ret = __sigaction(sig, sap, osv);
	return ret;
}