/*      $OpenBSD: shutdown.c,v 1.56 2024/04/28 16:43:42 florian Exp $   */
/*      $NetBSD: shutdown.c,v 1.9 1995/03/18 15:01:09 cgd Exp $ */

/*
 * Copyright (c) 1988, 1990, 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/resource.h>
#include <sys/syslog.h>
#include <sys/wait.h>

#include <ctype.h>
#include <fcntl.h>
#include <sys/termios.h>
#include <pwd.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <limits.h>
#include <errno.h>
#include <err.h>

#include "pathnames.h"

#ifdef DEBUG
#undef _PATH_NOLOGIN
#define _PATH_NOLOGIN   "./nologin"
#undef _PATH_FASTBOOT
#define _PATH_FASTBOOT  "./fastboot"
#endif

#define H               *60*60LL
#define M               *60LL
#define S               *1LL
#define TEN_HOURS       (10*60*60)
#define NOLOG_TIME      (5*60)
struct interval {
        time_t timeleft;
        time_t timetowait;
} tlist[] = {
        {    0,    0 },
        { 10 H,  5 H },
        {  5 H,  3 H },
        {  2 H,  1 H },
        {  1 H, 30 M },
        { 30 M, 10 M },
        { 20 M, 10 M },
        { 10 M,  5 M },
        {  5 M,  3 M },
        {  2 M,  1 M },
        {  1 M, 30 S },
        { 30 S, 30 S },
        {    0,    0 }
};
const int tlistlen = sizeof(tlist) / sizeof(tlist[0]);
#undef H
#undef M
#undef S

static time_t offset, shuttime;
static int dofast, dohalt, doreboot, dopower, dodump, mbuflen, nosync;
static volatile sig_atomic_t killflg, timed_out;
static char *whom, mbuf[BUFSIZ];

void badtime(void);
void __dead die_you_gravy_sucking_pig_dog(void);
void doitfast(void);
void __dead finish(int);
void getoffset(char *);
void __dead loop(void);
void nolog(time_t);
void timeout(int);
void timewarn(time_t);
void usage(void);

int
main(int argc, char *argv[])
{
        char when[64];
        char *p, *endp;
        struct passwd *pw;
        struct tm *lt;
        int arglen, ch, len, readstdin = 0;
        pid_t forkpid;

#ifndef DEBUG
        if (geteuid())
                errx(1, "NOT super-user");
#endif
        while ((ch = getopt(argc, argv, "dfhknpr-")) != -1)
                switch (ch) {
                case '-':
                        readstdin = 1;
                        break;
                case 'd':
                        dodump = 1;
                        break;
                case 'f':
                        dofast = 1;
                        break;
                case 'h':
                        dohalt = 1;
                        break;
                case 'k':
                        killflg = 1;
                        break;
                case 'n':
                        nosync = 1;
                        break;
                case 'p':
                        dopower = 1;
                        break;
                case 'r':
                        doreboot = 1;
                        break;
                default:
                        usage();
                }
        argc -= optind;
        argv += optind;

        if (argc < 1)
                usage();

        if (dofast && nosync) {
                warnx("incompatible switches -f and -n.");
                usage();
        }
        if (doreboot && dohalt) {
                warnx("incompatible switches -h and -r.");
                usage();
        }
        if (doreboot && dopower) {
                warnx("incompatible switches -p and -r.");
                usage();
        }

        if (unveil(_PATH_CONSOLE, "rw") == -1)
                err(1, "unveil %s", _PATH_CONSOLE);
        if (unveil(_PATH_RC, "r") == -1)
                err(1, "unveil %s", _PATH_RC);
        if (unveil(_PATH_WALL, "x") == -1)
                err(1, "unveil %s", _PATH_WALL);
        if (unveil(_PATH_FASTBOOT, "wc") == -1)
                err(1, "unveil %s", _PATH_FASTBOOT);
        if (unveil(_PATH_NOLOGIN, "wc") == -1)
                err(1, "unveil %s", _PATH_NOLOGIN);
        if (dohalt || dopower) {
                if (unveil(_PATH_HALT, "x") == -1)
                        err(1, "unveil %s", _PATH_HALT);
        } else if (doreboot) {
                if (unveil(_PATH_REBOOT, "x") == -1)
                        err(1, "unveil %s", _PATH_REBOOT);
        } else {
                if (unveil(_PATH_BSHELL, "x") == -1)
                        err(1, "unveil %s", _PATH_BSHELL);
        }
        if (pledge("stdio rpath wpath cpath getpw tty id proc exec", NULL) == -1)
                err(1, "pledge");

        getoffset(*argv++);

        if (*argv) {
                for (p = mbuf, len = sizeof(mbuf); *argv; ++argv) {
                        arglen = strlen(*argv);
                        if ((len -= arglen) <= 2)
                                break;
                        if (p != mbuf)
                                *p++ = ' ';
                        memcpy(p, *argv, arglen);
                        p += arglen;
                }
                *p = '\n';
                *++p = '\0';
        }

        if (readstdin) {
                p = mbuf;
                endp = mbuf + sizeof(mbuf) - 2;
                for (;;) {
                        if (!fgets(p, endp - p + 1, stdin))
                                break;
                        for (; *p &&  p < endp; ++p)
                                ;
                        if (p == endp) {
                                *p = '\n';
                                *++p = '\0';
                                break;
                        }
                }
        }
        mbuflen = strlen(mbuf);

        if (offset > 0) {
                shuttime = time(NULL) + offset;
                lt = localtime(&shuttime);
                if (lt != NULL) {
                        strftime(when, sizeof(when), "%a %b %e %T %Z %Y", lt);
                        printf("Shutdown at %s.\n", when);
                } else
                        printf("Shutdown soon.\n");
        } else
                printf("Shutdown NOW!\n");

        if (!(whom = getlogin()))
                whom = (pw = getpwuid(getuid())) ? pw->pw_name : "???";

#ifdef DEBUG
        (void)putc('\n', stdout);
#else
        (void)setpriority(PRIO_PROCESS, 0, PRIO_MIN);

        forkpid = fork();
        if (forkpid == -1)
                err(1, "fork");
        if (forkpid) {
                (void)printf("shutdown: [pid %ld]\n", (long)forkpid);
                exit(0);
        }
        setsid();
#endif
        openlog("shutdown", LOG_CONS, LOG_AUTH);
        loop();
        /* NOTREACHED */
}

void
loop(void)
{
        struct timespec timeout;
        int broadcast, i, logged;

        broadcast = 1;

        for (i = 0; i < tlistlen - 1; i++) {
                if (offset > tlist[i + 1].timeleft) {
                        tlist[i].timeleft = offset;
                        tlist[i].timetowait = offset - tlist[i + 1].timeleft;
                        break;
                }
        }

        /*
         * Don't spam the users: skip our offset's warning broadcast if
         * there's a broadcast scheduled after ours and it's relatively
         * imminent.
         */
        if (offset > TEN_HOURS ||
            (offset > 0 && tlist[i].timetowait < tlist[i+1].timetowait / 5))
                broadcast = 0;

        for (logged = 0; i < tlistlen; i++) {
                if (broadcast)
                        timewarn(tlist[i].timeleft);
                broadcast = 1;
                if (!logged && tlist[i].timeleft <= NOLOG_TIME) {
                        logged = 1;
                        nolog(tlist[i].timeleft);
                }
                timeout.tv_sec = tlist[i].timetowait;
                timeout.tv_nsec = 0;
                nanosleep(&timeout, NULL);
        }
        die_you_gravy_sucking_pig_dog();
}

static char *restricted_environ[] = {
        "PATH=" _PATH_STDPATH,
        NULL
};

void
timewarn(time_t timeleft)
{
        static char hostname[HOST_NAME_MAX+1];
        char when[64];
        struct tm *lt;
        static int first;
        int fd[2];
        pid_t pid, wpid;

        if (!first++)
                (void)gethostname(hostname, sizeof(hostname));

        if (pipe(fd) == -1) {
                syslog(LOG_ERR, "pipe: %m");
                return;
        }
        switch (pid = fork()) {
        case -1:
                syslog(LOG_ERR, "fork: %m");
                close(fd[0]);
                close(fd[1]);
                return;
        case 0:
                if (dup2(fd[0], STDIN_FILENO) == -1) {
                        syslog(LOG_ERR, "dup2: %m");
                        _exit(1);
                }
                if (fd[0] != STDIN_FILENO)
                        close(fd[0]);
                close(fd[1]);
                /* wall(1)'s undocumented '-n' flag suppresses its banner. */
                execle(_PATH_WALL, _PATH_WALL, "-n", (char *)NULL,
                    restricted_environ);
                syslog(LOG_ERR, "%s: %m", _PATH_WALL);
                _exit(1);
        default:
                close(fd[0]);
        }

        dprintf(fd[1],
            "\007*** %sSystem shutdown message from %s@%s ***\007\n",
            timeleft ? "": "FINAL ", whom, hostname);

        if (timeleft > 10 * 60) {
                shuttime = time(NULL) + timeleft;
                lt = localtime(&shuttime);
                if (lt != NULL) {
                        strftime(when, sizeof(when), "%H:%M %Z", lt);
                        dprintf(fd[1], "System going down at %s\n\n", when);
                } else
                        dprintf(fd[1], "System going down in %lld minute%s\n\n",
                            (long long)(timeleft / 60),
                            (timeleft > 60) ? "s" : "");
        } else if (timeleft > 59) {
                dprintf(fd[1], "System going down in %lld minute%s\n\n",
                    (long long)(timeleft / 60), (timeleft > 60) ? "s" : "");
        } else if (timeleft)
                dprintf(fd[1], "System going down in 30 seconds\n\n");
        else
                dprintf(fd[1], "System going down IMMEDIATELY\n\n");

        if (mbuflen)
                (void)write(fd[1], mbuf, mbuflen);
        close(fd[1]);

        /*
         * If we wait longer than 30 seconds for wall(1) to exit we'll
         * throw off our schedule.
         */
        signal(SIGALRM, timeout);
        siginterrupt(SIGALRM, 1);
        alarm(30);
        while ((wpid = wait(NULL)) != pid && !timed_out)
                continue;
        alarm(0);
        signal(SIGALRM, SIG_DFL);
        if (timed_out) {
                syslog(LOG_NOTICE,
                    "wall[%ld] is taking too long to exit; continuing",
                    (long)pid);
                timed_out = 0;
        }
}

void
timeout(int signo)
{
        timed_out = 1;
}

void
die_you_gravy_sucking_pig_dog(void)
{

        syslog(LOG_NOTICE, "%s by %s: %s",
            doreboot ? "reboot" : dopower ? "power-down" : dohalt ? "halt" :
            "shutdown", whom, mbuf);
        (void)sleep(2);

        (void)printf("\r\nSystem shutdown time has arrived\007\007\r\n");
        if (killflg) {
                (void)printf("\rbut you'll have to do it yourself\r\n");
                finish(0);
        }
        if (dofast)
                doitfast();

        if (pledge("stdio rpath wpath cpath tty id proc exec", NULL) == -1)
                err(1, "pledge");

#ifdef DEBUG
        if (doreboot)
                (void)printf("reboot");
        else if (dopower)
                (void)printf("power-down");
        else if (dohalt)
                (void)printf("halt");
        if (nosync)
                (void)printf(" no sync");
        if (dofast)
                (void)printf(" no fsck");
        if (dodump)
                (void)printf(" with dump");
        (void)printf("\nkill -HUP 1\n");
#else
        if (dohalt || dopower || doreboot) {
                char *args[10];
                char **arg, *path;

                if (pledge("stdio exec", NULL) == -1)
                        err(1, "pledge");

                arg = &args[0];
                if (doreboot) {
                        path = _PATH_REBOOT;
                        *arg++ = "reboot";
                } else {
                        path = _PATH_HALT;
                        *arg++ = "halt";
                }
                *arg++ = "-l";
                if (dopower)
                        *arg++ = "-p";
                if (nosync)
                        *arg++ = "-n";
                if (dodump)
                        *arg++ = "-d";
                *arg++ = NULL;
                execve(path, args, NULL);
                syslog(LOG_ERR, "shutdown: can't exec %s: %m.", path);
                warn("%s", path);
        }
        if (access(_PATH_RC, R_OK) != -1) {
                pid_t pid;
                struct termios t;
                int fd;

                switch ((pid = fork())) {
                case -1:
                        break;
                case 0:
                        if (revoke(_PATH_CONSOLE) == -1)
                                perror("revoke");
                        if (setsid() == -1)
                                perror("setsid");
                        fd = open(_PATH_CONSOLE, O_RDWR);
                        if (fd == -1)
                                perror("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:
                        waitpid(pid, NULL, 0);
                }
        }
        (void)kill(1, SIGTERM);         /* to single user */
#endif
        finish(0);
}

#define ATOI2(p)        (p[0] - '0') * 10 + (p[1] - '0'); p += 2;

void
getoffset(char *timearg)
{
        char when[64];
        const char *errstr;
        struct tm *lt;
        int this_year;
        time_t minutes, now;
        char *p;

        if (!strcasecmp(timearg, "now")) {              /* now */
                offset = 0;
                return;
        }

        if (timearg[0] == '+') {                        /* +minutes */
                minutes = strtonum(timearg, 0, INT_MAX, &errstr);
                if (errstr)
                        errx(1, "relative offset is %s: %s", errstr, timearg);
                offset = minutes * 60;
                return;
        }

        /* handle hh:mm by getting rid of the colon */
        for (p = timearg; *p; ++p) {
                if (!isascii((unsigned char)*p) || !isdigit((unsigned char)*p)) {
                        if (*p == ':' && strlen(p) == 3) {
                                p[0] = p[1];
                                p[1] = p[2];
                                p[2] = '\0';
                        } else
                                badtime();
                }
        }

        unsetenv("TZ");                                 /* OUR timezone */
        time(&now);
        lt = localtime(&now);                           /* current time val */

        if (lt == NULL)
                badtime();

        switch (strlen(timearg)) {
        case 10:
                this_year = lt->tm_year;
                lt->tm_year = ATOI2(timearg);
                /*
                 * check if the specified year is in the next century.
                 * allow for one year of user error as many people will
                 * enter n - 1 at the start of year n.
                 */
                if (lt->tm_year < (this_year % 100) - 1)
                        lt->tm_year += 100;
                /* adjust for the year 2000 and beyond */
                lt->tm_year += (this_year - (this_year % 100));
                /* FALLTHROUGH */
        case 8:
                lt->tm_mon = ATOI2(timearg);
                if (--lt->tm_mon < 0 || lt->tm_mon > 11)
                        badtime();
                /* FALLTHROUGH */
        case 6:
                lt->tm_mday = ATOI2(timearg);
                if (lt->tm_mday < 1 || lt->tm_mday > 31)
                        badtime();
                /* FALLTHROUGH */
        case 4:
                lt->tm_hour = ATOI2(timearg);
                if (lt->tm_hour < 0 || lt->tm_hour > 23)
                        badtime();
                lt->tm_min = ATOI2(timearg);
                if (lt->tm_min < 0 || lt->tm_min > 59)
                        badtime();
                lt->tm_sec = 0;
                if ((shuttime = mktime(lt)) == -1)
                        badtime();
                if ((offset = shuttime - now) < 0) {
                        strftime(when, sizeof(when), "%a %b %e %T %Z %Y", lt);
                        errx(1, "time is already past: %s", when);
                }
                break;
        default:
                badtime();
        }
}

void
doitfast(void)
{
        int fastfd;

        if ((fastfd = open(_PATH_FASTBOOT, O_WRONLY|O_CREAT|O_TRUNC,
            0664)) >= 0) {
                dprintf(fastfd, "fastboot file for fsck\n");
                close(fastfd);
        }
}

void
nolog(time_t timeleft)
{
        char when[64];
        struct tm *tm;
        int logfd;

        (void)unlink(_PATH_NOLOGIN);    /* in case linked to another file */
        (void)signal(SIGINT, finish);
        (void)signal(SIGHUP, finish);
        (void)signal(SIGQUIT, finish);
        (void)signal(SIGTERM, finish);
        shuttime = time(NULL) + timeleft;
        tm = localtime(&shuttime);
        if ((logfd = open(_PATH_NOLOGIN, O_WRONLY|O_CREAT|O_TRUNC,
            0664)) >= 0) {
                if (tm) {
                        strftime(when, sizeof(when), "at %H:%M %Z", tm);
                        dprintf(logfd,
                            "\n\nNO LOGINS: System going down %s\n\n", when);
                } else
                        dprintf(logfd,
                            "\n\nNO LOGINS: System going in %lld minute%s\n\n",
                            (long long)(timeleft / 60),
                            (timeleft > 60) ? "s" : "");
                close(logfd);
        }
}

void
finish(int signo)
{
        if (!killflg)
                (void)unlink(_PATH_NOLOGIN);
        if (signo == 0)
                exit(0);
        else
                _exit(0);
}

void
badtime(void)
{
        errx(1, "bad time format.");
}

void
usage(void)
{
        fprintf(stderr,
            "usage: shutdown [-] [-dfhknpr] time [warning-message ...]\n");
        exit(1);
}