/*
 * 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 (c) 1988 AT&T
 *        All Rights Reserved
 *
 * Copyright (c) 1992, 2010, Oracle and/or its affiliates. All rights reserved.
 */

/*
 * Utility functions
 */
#include        <unistd.h>
#include        <signal.h>
#include        <locale.h>
#include        <string.h>
#include        "msg.h"
#include        "_libld.h"

/*
 * Exit after cleaning up.
 */
int
ld_exit(Ofl_desc *ofl)
{
        /*
         * If we have created an output file remove it.
         */
        if ((ofl->ofl_fd > 0) && ((ofl->ofl_flags1 & FLG_OF1_NONREG) == 0))
                (void) unlink(ofl->ofl_name);

        /*
         * Inform any support library that the link-edit has failed.
         */
        ld_sup_atexit(ofl, 1);

        /*
         * Wrap up debug output file if one is open
         */
        dbg_cleanup();

        /* If any ERR_GUIDANCE messages were issued, add a summary */
        if (ofl->ofl_guideflags & FLG_OFG_ISSUED)
                ld_eprintf(ofl, ERR_GUIDANCE, MSG_INTL(MSG_GUIDE_SUMMARY));

        return (1);
}

/*
 * Establish the signals we're interested in, and the handlers that need to be
 * reinstalled should any of these signals occur.
 */
typedef struct {
        int     signo;
        void (* defhdl)();
} Signals;

static Signals signals[] = {
        { SIGHUP,       SIG_DFL },
        { SIGINT,       SIG_IGN },
        { SIGQUIT,      SIG_DFL },
        { SIGBUS,       SIG_DFL },
        { SIGTERM,      SIG_IGN },
        { 0,            0 } };

static Ofl_desc *Ofl = NULL;

/*
 * Define our signal handler.
 */
static void
/* ARGSUSED2 */
handler(int sig, siginfo_t *sip, void *utp)
{
        struct sigaction        nact;
        Signals *               sigs;

        /*
         * Reset all ignore handlers regardless of how we got here.
         */
        nact.sa_handler = SIG_IGN;
        nact.sa_flags = 0;
        (void) sigemptyset(&nact.sa_mask);

        for (sigs = signals; sigs->signo; sigs++) {
                if (sigs->defhdl == SIG_IGN)
                        (void) sigaction(sigs->signo, &nact, NULL);
        }

        /*
         * The model for creating an output file is to ftruncate() it to the
         * required size and mmap() a mapping into which the new contents are
         * written.  Neither of these operations guarantee that the required
         * disk blocks exist, and should we run out of disk space a bus error
         * is generated.
         * Other situations have been reported to result in ld catching a bus
         * error (one instance was a stale NFS handle from an unstable server).
         * Thus we catch all bus errors and hope we can decode a better error.
         */
        if ((sig == SIGBUS) && sip && Ofl->ofl_name) {
                ld_eprintf(Ofl, ERR_FATAL, MSG_INTL(MSG_FIL_INTERRUPT),
                    Ofl->ofl_name, strerror(sip->si_errno));
        }
        /*
         * This assert(0) causes DEBUG enabled linkers to produce a core file.
         */
        if ((sig != SIGHUP) && (sig != SIGINT))
                assert(0);

        exit(ld_exit(Ofl));
}

/*
 * Establish a signal handler for all signals we're interested in.
 */
void
ld_init_sighandler(Ofl_desc *ofl)
{
        struct sigaction        nact, oact;
        Signals *               sigs;

        Ofl = ofl;

        /*
         * Our heavy use of mmap() means that we are susceptible to
         * receiving a SIGBUS in low diskspace situations. The main
         * purpose of the signal handler is to handle that situation
         * gracefully, so that out of disk errors don't drop a core file.
         *
         * In rare cases, this will prevent us from getting a core from a
         * SIGBUS triggered by an internal alignment error in libld.
         * If -znosighandler is set, return without registering the
         * handler. This is primarily of use for debugging problems in
         * the field, and is not of general interest.
         */
        if (ofl->ofl_flags1 & FLG_OF1_NOSGHND)
                return;

        /*
         * For each signal we're interested in set up a signal handler that
         * insures we clean up any output file we're in the middle of creating.
         */
        nact.sa_sigaction = handler;
        (void) sigemptyset(&nact.sa_mask);

        for (sigs = signals; sigs->signo; sigs++) {
                if ((sigaction(sigs->signo, NULL, &oact) == 0) &&
                    (oact.sa_handler != SIG_IGN)) {
                        nact.sa_flags = SA_SIGINFO;
                        if (sigs->defhdl == SIG_DFL)
                                nact.sa_flags |= (SA_RESETHAND | SA_NODEFER);
                        (void) sigaction(sigs->signo, &nact, NULL);
                }
        }
}