/*      $OpenBSD: reboot.c,v 1.38 2017/08/22 00:30:16 sf Exp $  */
/*      $NetBSD: reboot.c,v 1.8 1995/10/05 05:36:22 mycroft Exp $       */

/*
 * 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.
 */

#include <sys/types.h>
#include <sys/reboot.h>
#include <sys/sysctl.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <machine/cpu.h>
#include <signal.h>
#include <pwd.h>
#include <errno.h>
#include <err.h>
#include <fcntl.h>
#include <termios.h>
#include <syslog.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <paths.h>
#include <util.h>

void    usage(void);
extern char *__progname;

int     dohalt;

#define _PATH_RC        "/etc/rc"

static void
sleep_while_procs(int seconds)
{
        while (seconds > 0) {
                if (kill(-1, 0) == -1 && errno == ESRCH)
                        return;
                sleep(1);
                seconds--;
        }
}

int
main(int argc, char *argv[])
{
        unsigned int i;
        struct passwd *pw;
        int ch, howto, lflag, nflag, pflag, qflag;
        char *p, *user;
        sigset_t mask;

        p = __progname;

        /* Nuke login shell */
        if (*p == '-')
                p++;

        howto = dohalt = lflag = nflag = pflag = qflag = 0;
        if (!strcmp(p, "halt")) {
                dohalt = 1;
                howto = RB_HALT;
        }

        while ((ch = getopt(argc, argv, "dlnpq")) != -1)
                switch (ch) {
                case 'd':
                        howto |= RB_DUMP;
                        break;
                case 'l':       /* Undocumented; used by shutdown. */
                        lflag = 1;
                        break;
                case 'n':
                        nflag = 1;
                        howto |= RB_NOSYNC;
                        break;
                case 'p':
                        /* Only works if we're called as halt. */
                        if (dohalt) {
                                pflag = 1;
                                howto |= RB_POWERDOWN;
                        }
                        break;
                case 'q':
                        qflag = 1;
                        break;
                default:
                        usage();
                }
        argc -= optind;
        argv += optind;

        if (argc)
                usage();

        if (geteuid())
                errx(1, "%s", strerror(EPERM));

#ifdef CPU_LIDACTION
        if (howto & RB_POWERDOWN) {
                /* Disable suspending on laptop lid close */
                int mib[] = {CTL_MACHDEP, CPU_LIDACTION};
                int lidaction = 0;

                if (sysctl(mib, 2, NULL, NULL, &lidaction,
                    sizeof(lidaction)) == -1 && errno != EOPNOTSUPP)
                        warn("sysctl");
        }
#endif /* CPU_LIDACTION */

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

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

        /*
         * 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. */
        (void)signal(SIGHUP, SIG_IGN);

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

        if (access(_PATH_RC, R_OK) != -1) {
                pid_t pid;
                struct termios t;
                int fd, status;

                switch ((pid = fork())) {
                case -1:
                        break;
                case 0:
                        if (revoke(_PATH_CONSOLE) == -1)
                                warn("revoke");
                        if (setsid() == -1)
                                warn("setsid");
                        fd = open(_PATH_CONSOLE, O_RDWR);
                        if (fd == -1)
                                warn("open");
                        dup2(fd, 0);
                        dup2(fd, 1);
                        dup2(fd, 2);
                        if (fd > 2)
                                close(fd);

                        /* At a minimum... */
                        tcgetattr(0, &t);
                        t.c_oflag |= (ONLCR | OPOST);
                        tcsetattr(0, TCSANOW, &t);

                        execl(_PATH_BSHELL, "sh", _PATH_RC, "shutdown", (char *)NULL);
                        _exit(1);
                default:
                        /* rc exits 2 if powerdown=YES in rc.shutdown */
                        waitpid(pid, &status, 0);
                        if (dohalt && WIFEXITED(status) && WEXITSTATUS(status) == 2)
                                howto |= RB_POWERDOWN;
                }
        }

        /*
         * Point of no return, block all signals so we are sure to
         * reach the call to reboot(2) unmolested.
         */
        sigfillset(&mask);
        sigprocmask(SIG_BLOCK, &mask, NULL);

        /* Send a SIGTERM first, a chance to save the buffers. */
        if (kill(-1, SIGTERM) == -1) {
                /*
                 * If ESRCH, everything's OK: we're the only non-system
                 * process!  That can happen e.g. via 'exec reboot' in
                 * single-user mode.
                 */
                if (errno != ESRCH) {
                        warn("SIGTERM processes");
                        goto restart;
                }
        }

        /*
         * 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.
         */
        sleep_while_procs(2);
        if (!nflag)
                sync();
        sleep_while_procs(3);

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

        reboot(howto);
        /* FALLTHROUGH */

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

void
usage(void)
{
        fprintf(stderr, "usage: %s [-dn%sq]\n", __progname,
            dohalt ? "p" : "");
        exit(1);
}