usr/src/lib/libc/port/sys/sigstack.c

   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 #pragma ident   "%Z%%M% %I%     %E% SMI"
  31
  32 #include "lint.h"
  33 #include <sys/types.h>
  34 #include <sys/ucontext.h>
  35 #include <signal.h>
  36 #include <errno.h>
  37
  38 int
  39 sigstack(struct sigstack *nss, struct sigstack *oss)
  40 {
  41         struct sigaltstack nalt;
  42         struct sigaltstack oalt;
  43         struct sigaltstack *naltp;
  44
  45         if (nss) {
  46                 /* Assumes stack growth is down */
  47                 nalt.ss_sp = (char *)nss->ss_sp - SIGSTKSZ;
  48                 nalt.ss_size = SIGSTKSZ;
  49                 nalt.ss_flags = 0;
  50                 naltp = &nalt;
  51         } else
  52                 naltp = NULL;
  53
  54         if (sigaltstack(naltp, &oalt) < 0)
  55                 return (-1);
  56
  57         if (oss) {
  58                 /* Assumes stack growth is down */
  59                 oss->ss_sp = (char *)oalt.ss_sp + oalt.ss_size;
  60                 oss->ss_onstack = ((oalt.ss_flags & SS_ONSTACK) != 0);
  61         }
  62         return (0);
  63 }