xref: /titanic_44/usr/src/lib/libc/port/sys/sigstack.c (revision 6dfee4834394825da35b977ca71cdc965bc7b6a4)
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, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 2004 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 #pragma ident	"%Z%%M%	%I%	%E% SMI"
31 
32 #pragma weak sigstack = _sigstack
33 
34 #include "lint.h"
35 #include <sys/types.h>
36 #include <sys/ucontext.h>
37 #include <signal.h>
38 #include <errno.h>
39 
40 int
41 _sigstack(struct sigstack *nss, struct sigstack *oss)
42 {
43 	struct sigaltstack nalt;
44 	struct sigaltstack oalt;
45 	struct sigaltstack *naltp;
46 
47 	if (nss) {
48 		/* Assumes stack growth is down */
49 		nalt.ss_sp = (char *)nss->ss_sp - SIGSTKSZ;
50 		nalt.ss_size = SIGSTKSZ;
51 		nalt.ss_flags = 0;
52 		naltp = &nalt;
53 	} else
54 		naltp = (struct sigaltstack *)0;
55 
56 	if (sigaltstack(naltp, &oalt) < 0)
57 		return (-1);
58 
59 	if (oss) {
60 		/* Assumes stack growth is down */
61 		oss->ss_sp = (char *)oalt.ss_sp + oalt.ss_size;
62 		oss->ss_onstack = ((oalt.ss_flags & SS_ONSTACK) != 0);
63 	}
64 	return (0);
65 }
66