port/sys/sigstack.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*  Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/*    All Rights Reserved   */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include "lint.h"
#include <sys/types.h>
#include <sys/ucontext.h>
#include <signal.h>
#include <errno.h>

int
sigstack(struct sigstack *nss, struct sigstack *oss)
{
    struct sigaltstack nalt;
    struct sigaltstack oalt;
    struct sigaltstack *naltp;

    if (nss) {
        /* Assumes stack growth is down */
        nalt.ss_sp = (char *)nss->ss_sp - SIGSTKSZ;
        nalt.ss_size = SIGSTKSZ;
        nalt.ss_flags = 0;
        naltp = &nalt;
    } else
        naltp = (struct sigaltstack *)0;

    if (sigaltstack(naltp, &oalt) < 0)
        return (-1);

    if (oss) {
        /* Assumes stack growth is down */
        oss->ss_sp = (char *)oalt.ss_sp + oalt.ss_size;
        oss->ss_onstack = ((oalt.ss_flags & SS_ONSTACK) != 0);
    }
    return (0);
}