/*
 * Copyright (c) 1980, 1986, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * @(#) Copyright (c) 1980, 1986, 1993 The Regents of the University of California.  All rights reserved.
 * @(#)reboot.c 8.1 (Berkeley) 6/5/93
 * $FreeBSD: src/sbin/reboot/reboot.c,v 1.9.2.4 2002/04/28 22:50:00 wes Exp $
 */

#include <sys/reboot.h>
#include <sys/types.h>
#include <sys/sysctl.h>
#include <signal.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <libutil.h>
#include <pwd.h>
#include <syslog.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <utmpx.h>

static void usage(void) __dead2;
static u_int get_pageins(void);

static int dohalt;

int
main(int argc, char *argv[])
{
        struct passwd *pw;
        int ch, howto, i, lflag, nflag, qflag, sverrno;
        u_int pageins;
        char *p;
        const char *user;

        if (strstr((p = strrchr(*argv, '/')) ? p + 1 : *argv, "halt")) {
                dohalt = 1;
                howto = RB_HALT;
        } else
                howto = 0;
        lflag = nflag = qflag = 0;
        while ((ch = getopt(argc, argv, "dlnpq")) != -1)
                switch(ch) {
                case 'd':
                        howto |= RB_DUMP;
                        break;
                case 'l':
                        lflag = 1;
                        break;
                case 'n':
                        nflag = 1;
                        howto |= RB_NOSYNC;
                        break;
                case 'p':
                        howto |= (RB_POWEROFF | RB_HALT);
                        break;
                case 'q':
                        qflag = 1;
                        break;
                case '?':
                default:
                        usage();
                }
        argc -= optind;
        argv += optind;
        if (argc != 0)
                usage();

        if ((howto & (RB_DUMP | RB_HALT)) == (RB_DUMP | RB_HALT))
                errx(1, "cannot dump (-d) when halting; must reboot instead");
        if (geteuid()) {
                errno = EPERM;
                err(1, NULL);
        }

        if (qflag) {
                reboot(howto);
                err(1, NULL);
        }

        /* Log the reboot. */
        if (!lflag)  {
                if ((user = getlogin()) == NULL)
                        user = (pw = getpwuid(getuid())) ?
                            pw->pw_name : "???";
                if (dohalt) {
                        openlog("halt", LOG_CONS, LOG_AUTH);
                        syslog(LOG_CRIT, "halted by %s", user);
                } else {
                        openlog("reboot", LOG_CONS, LOG_AUTH);
                        syslog(LOG_CRIT, "rebooted by %s", user);
                }
        }
        logwtmpx("~", "shutdown", "", 0, INIT_PROCESS);

        /*
         * Do a sync early on, so disks start transfers while we're off
         * killing processes.  Don't worry about writes done before the
         * processes die, the reboot system call syncs the disks.
         */
        if (!nflag)
                sync();

        /* Just stop init -- if we fail, we'll restart it. */
        if (kill(1, SIGTSTP) == -1)
                err(1, "SIGTSTP init");

        /* Ignore the SIGHUP we get when our parent shell dies. */
        signal(SIGHUP, SIG_IGN);
        /* parent shell might also send a SIGTERM?  Best to ignore as well */
        signal(SIGTERM, SIG_IGN);
        /* Group leaders may try killing us with other signals, ignore */
        signal(SIGINT,  SIG_IGN);
        signal(SIGQUIT, SIG_IGN);
        signal(SIGTSTP, SIG_IGN);

        /*
         * If we're running in a pipeline, we don't want to die
         * after killing whatever we're writing to.
         */
        signal(SIGPIPE, SIG_IGN);

        /* Send a SIGTERM first, a chance to save the buffers. */
        if (kill(-1, SIGTERM) == -1)
                err(1, "SIGTERM processes");

        /*
         * After the processes receive the signal, start the rest of the
         * buffers on their way.  Wait 5 seconds between the SIGTERM and
         * the SIGKILL to give everybody a chance. If there is a lot of
         * paging activity then wait longer, up to a maximum of approx
         * 60 seconds.
         */
        sleep(2);
        for (i = 0; i < 20; i++) {
                pageins = get_pageins();
                if (!nflag)
                        sync();
                sleep(3);
                if (get_pageins() == pageins)
                        break;
        }

        for (i = 1;; ++i) {
                if (kill(-1, SIGKILL) == -1) {
                        if (errno == ESRCH)
                                break;
                        goto restart;
                }
                if (i > 5) {
                        fprintf(stderr,
                            "WARNING: some process(es) wouldn't die\n");
                        break;
                }
                sleep(2 * i);
        }

        reboot(howto);
        /* FALLTHROUGH */

restart:
        sverrno = errno;
        errx(1, "%s%s", kill(1, SIGHUP) == -1 ? "(can't restart init): " : "",
            strerror(sverrno));
        /* NOTREACHED */
}

static void
usage(void)
{
        fprintf(stderr, "usage: %s [-dnpq]\n", dohalt ? "halt" : "reboot");
        exit(1);
}

static u_int
get_pageins(void)
{
        u_int pageins;
        size_t len;

        len = sizeof(pageins);
        if (sysctlbyname("vm.stats.vm.v_swappgsin", &pageins, &len, NULL, 0)
            != 0) {
                warnx("v_swappgsin");
                return (0);
        }
        return pageins;
}