xref: /illumos-gate/usr/src/lib/libc/port/sys/sigstack.c (revision 9b9d39d2a32ff806d2431dbcc50968ef1e6d46b2)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
28 /*	  All Rights Reserved  	*/
29 
30 #include "lint.h"
31 #include <sys/types.h>
32 #include <sys/ucontext.h>
33 #include <signal.h>
34 #include <errno.h>
35 
36 int
37 sigstack(struct sigstack *nss, struct sigstack *oss)
38 {
39 	struct sigaltstack nalt;
40 	struct sigaltstack oalt;
41 	struct sigaltstack *naltp;
42 
43 	if (nss) {
44 		/* Assumes stack growth is down */
45 		nalt.ss_sp = (char *)nss->ss_sp - SIGSTKSZ;
46 		nalt.ss_size = SIGSTKSZ;
47 		nalt.ss_flags = 0;
48 		naltp = &nalt;
49 	} else
50 		naltp = (struct sigaltstack *)0;
51 
52 	if (sigaltstack(naltp, &oalt) < 0)
53 		return (-1);
54 
55 	if (oss) {
56 		/* Assumes stack growth is down */
57 		oss->ss_sp = (char *)oalt.ss_sp + oalt.ss_size;
58 		oss->ss_onstack = ((oalt.ss_flags & SS_ONSTACK) != 0);
59 	}
60 	return (0);
61 }
62