/*
 * shutdown.c	Shut the system down.
 *
 * Usage:	shutdown [-krhfnc] time [warning message]
 *		  -k: don't really shutdown, only warn.
 *		  -r: reboot after shutdown.
 *		  -h: halt after shutdown.
 *		  -f: do a 'fast' reboot (skip fsck).
 *		  -F: Force fsck on reboot.
 *		  -n: do not go through init but do it ourselves.
 *		  -c: cancel an already running shutdown.
 *		  -t secs: delay between SIGTERM and SIGKILL for init.
 *
 * Author:	Miquel van Smoorenburg, miquels@cistron.nl
 *
 * Version:	@(#)shutdown  2.86-1  31-Jul-2004  miquels@cistron.nl
 *
 *		This file is part of the sysvinit suite,
 *		Copyright (C) 1991-2004 Miquel van Smoorenburg.
 *
 *		This program is free software; you can redistribute it and/or modify
 *		it under the terms of the GNU General Public License as published by
 *		the Free Software Foundation; either version 2 of the License, or
 *		(at your option) any later version.
 *
 *		This program is distributed in the hope that it will be useful,
 *		but WITHOUT ANY WARRANTY; without even the implied warranty of
 *		MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *		GNU General Public License for more details.
 *
 *		You should have received a copy of the GNU General Public License
 *		along with this program; if not, write to the Free Software
 *		Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */
#ifndef _GNU_SOURCE
# define _GNU_SOURCE	/* otherwise `extern char **environ' is missed */
#endif
#ifndef ACCTON_OFF
# define ACCTON_OFF	0
#endif
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/wait.h>
#ifdef __linux__
#include <sys/sysmacros.h>   /* brought in my LFS patch */
#endif
#include <time.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <errno.h>
#include <stdlib.h>
#include <stdio.h> 
#include <signal.h>
#include <fcntl.h>
#include <stdarg.h>
#include <utmp.h>
#include <syslog.h>
#include "paths.h"
#include "reboot.h"
#include "initreq.h"
#include "init.h"


char *Version = "@(#) shutdown 2.90-1 31-Jul-2004 miquels@cistron.nl";

#define MESSAGELEN	256

int dontshut = 0;	/* Don't shutdown, only warn	*/
char down_level[2];	/* What runlevel to go to.	*/
int dosync = 1;		/* Sync before reboot or halt	*/
int fastboot = 0;	/* Do a 'fast' reboot		*/
int forcefsck = 0;	/* Force fsck on reboot		*/
char message[MESSAGELEN];	/* Warning message	*/
char *sltime = 0;	/* Sleep time			*/
char newstate[64];	/* What are we gonna do		*/
int doself = 0;		/* Don't use init		*/
int got_alrm = 0;

char *clean_env[] = {
	"HOME=/",
	"PATH=" PATH_DEFAULT,
	"TERM=dumb",
	"SHELL=/bin/sh",
	NULL,
};

/* From "utmp.c" */
extern void write_wtmp(char *user, char *id, int pid, int type, char *line);

/*
 *	Sleep without being interrupted.
 */
void hardsleep(int secs)
{
	struct timespec ts, rem;

	ts.tv_sec = secs;
	ts.tv_nsec = 0;

	while(nanosleep(&ts, &rem) < 0 && errno == EINTR)
		ts = rem;
}

/*
 *	Break off an already running shutdown.
 */
# ifdef __GNUC__
void stopit(int sig __attribute__((unused)))
# else
void stopit(int sig)
# endif

{
	unlink(NOLOGIN);
	unlink(FASTBOOT);
	unlink(FORCEFSCK);
	unlink(SDPID);
	printf("\r\nShutdown cancelled.\r\n");
	exit(0);
}

/*
 *	Show usage message.
 */
void usage(void)
{
	fprintf(stderr,
	"Usage:\t  shutdown [-akrhPHfFnc] [-t sec] time [warning message]\n"
	"\t\t  -a:      use /etc/shutdown.allow\n"
	"\t\t  -k:      don't really shutdown, only warn.\n"
	"\t\t  -r:      reboot after shutdown.\n"
	"\t\t  -h:      halt after shutdown.\n"
	"\t\t  -P:      halt action is to turn off power.\n"
	"\t\t  -H:      halt action is to just halt.\n"
	"\t\t  -f:      do a 'fast' reboot (skip fsck).\n"
	"\t\t  -F:      Force fsck on reboot.\n"
	"\t\t  -n:      do not go through \"init\" but go down real fast.\n"
	"\t\t  -c:      cancel a running shutdown.\n"
	"\t\t  -t secs: delay between warning and kill signal.\n"
	"\t\t  ** the \"time\" argument is mandatory! (try \"now\") **\n");
	exit(1);
}


void alrm_handler(int sig)
{
	got_alrm = sig;
}


/*
 *	Set environment variables in the init process.
 */
int init_setenv(char *name, char *value)
{
	struct init_request	request;
	struct sigaction	sa;
	int			fd;
	size_t			nl, vl;

	memset(&request, 0, sizeof(request));
	request.magic = INIT_MAGIC;
	request.cmd = INIT_CMD_SETENV;
	nl = strlen(name);
	vl = value ? strlen(value) : 0;

	if (nl + vl + 3 >= (int)sizeof(request.i.data))
		return -1;

	memcpy(request.i.data, name, nl);
	if (value) {
		request.i.data[nl] = '=';
		memcpy(request.i.data + nl + 1, value, vl);
	}

        /*
	 *	Open the fifo and write the command.
         *	Make sure we don't hang on opening /run/initctl
	 */
	memset(&sa, 0, sizeof(sa));
	sa.sa_handler = alrm_handler;
	sigaction(SIGALRM, &sa, NULL);
	got_alrm = 0;
	alarm(3);
	if ((fd = open(INIT_FIFO, O_WRONLY)) >= 0) {
		ssize_t p = 0;
		size_t s  = sizeof(request);
		void *ptr = &request;
		while (s > 0) {
			p = write(fd, ptr, s);
			if (p < 0) {
				if (errno == EINTR || errno == EAGAIN)
					continue;
				break;
			}
			ptr += p;
			s -= p;
		}
		close(fd);
		alarm(0);
		return 0;
	}
                                                                                
	fprintf(stderr, "shutdown: ");
	if (got_alrm) {
		fprintf(stderr, "timeout opening/writing control channel %s\n",
			INIT_FIFO);
	} else {
		perror(INIT_FIFO);
	}
	return -1;
}


/*
 *	Tell everyone the system is going down in 'mins' minutes.
 */
void issue_warn(int mins)
{
	char buf[MESSAGELEN + sizeof(newstate)];
	int len;

	buf[0] = 0;
	strncat(buf, message, sizeof(buf) - 1);
	len = strlen(buf);

	if (mins == 0)
		snprintf(buf + len, sizeof(buf) - len,
			"\rThe system is going down %s NOW!\r\n",
			newstate);
	else
  		snprintf(buf + len, sizeof(buf) - len,
			"\rThe system is going DOWN %s in %d minute%s!\r\n",
				newstate, mins, mins == 1 ? "" : "s");
	wall(buf, 0);
}

/*
 *	Create the /etc/nologin file.
 */
void donologin(int min)
{
	FILE *fp;
	time_t t;

	time(&t);
	t += 60 * min;

	if ((fp = fopen(NOLOGIN, "w")) != NULL) {
  		fprintf(fp, "\rThe system is going down on %s\r\n", ctime(&t));
  		if (message[0]) fputs(message, fp);
  		fclose(fp);
	}
}

/*
 *	Spawn an external program.
 */
int spawn(int noerr, char *prog, ...)
{
	va_list	ap;
	pid_t	pid, rc;
	int	i;
	char	*argv[8];

	i = 0;
	while ((pid = fork()) < 0 && i < 10) {
		perror("fork");
		sleep(5);
		i++;
	}

	if (pid < 0) return -1;

	if (pid > 0) {
		while((rc = wait(&i)) != pid)
			if (rc < 0 && errno == ECHILD)
				break;
		return (rc == pid) ? WEXITSTATUS(i) : -1;
	}

	if (noerr) fclose(stderr);

	argv[0] = prog;
	va_start(ap, prog);
	for (i = 1; i < 7 && (argv[i] = va_arg(ap, char *)) != NULL; i++)
		;
	argv[i] = NULL;
	va_end(ap);

	if (chdir("/"))
		exit(1);
	environ = clean_env;

	execvp(argv[0], argv);
	perror(argv[0]);
	exit(1);

	/*NOTREACHED*/
	return 0;
}

/*
 *	Kill all processes, call /etc/init.d/halt (if present)
 */
void fastdown()
{
	int do_halt = (down_level[0] == '0');
	int i;
#if 0
	char cmd[128];
	char *script;

	/*
	 *	Currently, the halt script is either init.d/halt OR rc.d/rc.0,
	 *	likewise for the reboot script. Test for the presence
	 *	of either.
	 */
	if (do_halt) {
		if (access(HALTSCRIPT1, X_OK) == 0)
			script = HALTSCRIPT1;
		else
			script = HALTSCRIPT2;
	} else {
		if (access(REBOOTSCRIPT1, X_OK) == 0)
			script = REBOOTSCRIPT1;
		else
			script = REBOOTSCRIPT2;
	}
#endif

	/* First close all files. */
	for(i = 0; i < 3; i++)
		if (!isatty(i)) {
			close(i);
			open("/dev/null", O_RDWR);
		}
	for(i = 3; i < 20; i++) close(i);
	close(255);

	/* First idle init. */
	if (kill(1, SIGTSTP) < 0) {
		fprintf(stderr, "shutdown: can't idle init: %s.\r\n", strerror(errno));
		exit(1);
	}

	/* Kill all processes. */
	fprintf(stderr, "shutdown: sending all processes the TERM signal...\r\n");
	kill(-1, SIGTERM);
	sleep(sltime ? atoi(sltime) : 3);
	fprintf(stderr, "shutdown: sending all processes the KILL signal.\r\n");
	(void) kill(-1, SIGKILL);

#if 0
	/* See if we can run /etc/init.d/halt */
	if (access(script, X_OK) == 0) {
		spawn(1, cmd, "fast", NULL);
		fprintf(stderr, "shutdown: %s returned - falling back "
				"on default routines\r\n", script);
	}
#endif

	/* script failed or not present: do it ourself. */
	/* Give init the chance to collect zombies. */
        /* sleep(1); */

	/* Record the fact that we're going down */
	write_wtmp("shutdown", "~~", 0, RUN_LVL, "~~");

	/* This is for those who have quota installed. */
#if defined(ACCTON_OFF)
# if (ACCTON_OFF > 1) && (_BSD_SOURCE || (_XOPEN_SOURCE && _XOPEN_SOURCE < 500))
	/* This is an alternative way to disable accounting, saving a fork() */
	if (acct(NULL))
		fprintf(stderr, "shutdown: can not stop process accounting: %s.\r\n", strerror(errno));
# elif (ACCTON_OFF > 0)
	spawn(1, "accton", "off", NULL);
# else
	spawn(1, "accton", NULL);
# endif
#endif
	spawn(1, "quotaoff", "-a", NULL);

	sync();
	fprintf(stderr, "shutdown: turning off swap\r\n");
	spawn(0, "swapoff", "-a", NULL);
	fprintf(stderr, "shutdown: unmounting all file systems\r\n");
	spawn(0, "umount", "-a", NULL);

	/* We're done, halt or reboot now. */
	if (do_halt) {
		fprintf(stderr, "The system is halted. Press CTRL-ALT-DEL "
				"or turn off power\r\n");
		init_reboot(BMAGIC_HALT);
		exit(0);
	}

	fprintf(stderr, "Please stand by while rebooting the system.\r\n");
	init_reboot(BMAGIC_REBOOT);
	exit(0);
}

/*
 *	Go to runlevel 0, 1 or 6.
 */
void issue_shutdown(char *halttype)
{
	char	*args[8];
	int	argp = 0;
	int	do_halt = (down_level[0] == '0');

	/* Warn for the last time */
	issue_warn(0);
	if (dontshut) {
		hardsleep(1);
		stopit(0);
	}
	openlog("shutdown", LOG_PID, LOG_USER);
	if (do_halt)
  		syslog(LOG_NOTICE, "shutting down for system halt");
	else
		syslog(LOG_NOTICE, "shutting down for system reboot");
	closelog();

	/* See if we have to do it ourself. */
	if (doself) fastdown();

	/* Create the arguments for init. */
	args[argp++] = INIT;
	if (sltime) {
		args[argp++] = "-t";
		args[argp++] = sltime;
	}
	args[argp++] = down_level;
	args[argp]   = (char *)NULL;

	unlink(SDPID);
	unlink(NOLOGIN);

	/* Now execute init to change runlevel. */
	sync();
	init_setenv("INIT_HALT", halttype);
	execv(INIT, args);

	/* Oops - failed. */
	fprintf(stderr, "\rshutdown: cannot execute %s\r\n", INIT);
	unlink(FASTBOOT);
	unlink(FORCEFSCK);
	init_setenv("INIT_HALT", NULL);
	openlog("shutdown", LOG_PID, LOG_USER);
	syslog(LOG_NOTICE, "shutdown failed");
	closelog();
	exit(1);
}

/*
 *	returns if a warning is to be sent for wt
 */
static int needwarning(int wt)
{
	int ret;

	if (wt < 10)
		ret = 1;
	else if (wt < 60)
		ret = (wt % 15 == 0);
	else if (wt < 180)
		ret = (wt % 30 == 0);
	else
		ret = (wt % 60 == 0);

	return ret;
}

/*
 *	Main program.
 *	Process the options and do the final countdown.
 */
int main(int argc, char **argv)
{
	FILE			*fp;
	extern int		getopt();
	extern int		optind; 
	struct sigaction	sa;
	struct tm		*lt;
	struct stat		st;
	struct utmp		*ut;
	time_t			t, target_time;
	char			*halttype;
	char			*downusers[32];
	char			buf[128];
	char			term[UT_LINESIZE + 6];
	char			*sp;
	char			*when = NULL;
	int			c, i, wt;
	int			hours, mins;
	int			didnolog = 0;
	int			cancel = 0;
	int			useacl = 0;
	int			pid = 0;
	int			user_ok = 0;

	/* We can be installed setuid root (executable for a special group) */
	/* 
        This way is risky, do error check on setuid call.
        setuid(geteuid());
        */
        errno = 0;
        if (setuid(geteuid()) == -1) {
            fprintf(stderr, "%s (%d): %s\n", __FILE__, __LINE__, strerror(errno));
            abort();
	}

	if (getuid() != 0) {
  		fprintf(stderr, "shutdown: you must be root to do that!\n");
		usage();
  		exit(1);
	}
	strcpy(down_level, "1");
	halttype = NULL;

	/* Process the options. */
	while((c = getopt(argc, argv, "HPacqkrhnfFyt:g:i:")) != EOF) {
  		switch(c) {
			case 'H':
				halttype = "HALT";
				break;
			case 'P':
				halttype = "POWERDOWN";
				break;
			case 'a': /* Access control. */
				useacl = 1;
				break;
			case 'c': /* Cancel an already running shutdown. */
				cancel = 1;
				break;
  			case 'k': /* Don't really shutdown, only warn.*/
  				dontshut = 1;
  				break;
  			case 'r': /* Automatic reboot */
				down_level[0] = '6';
  				break;
  			case 'h': /* Halt after shutdown */
				down_level[0] = '0';
  				break;
  			case 'f': /* Don't perform fsck after next boot */
  				fastboot = 1;
  				break;
  			case 'F': /* Force fsck after next boot */
  				forcefsck = 1;
  				break;
			case 'n': /* Don't switch runlevels. */
				doself = 1;
				break;
			case 't': /* Delay between TERM and KILL */
				sltime = optarg;
				break;
			case 'y': /* Ignored for sysV compatibility */
				break;
			case 'g': /* sysv style to specify time. */
				when = optarg;
				break;
			case 'i': /* Level to go to. */
				if (!strchr("0156aAbBcCsS", optarg[0])) {
					fprintf(stderr,
					"shutdown: `%s': bad runlevel\n",
					optarg);
					exit(1);
				}
				down_level[0] = optarg[0];
				break;
  			default:
  				usage();
  				break;	
  		}
	}

	if (NULL != halttype && down_level[0] != '0') {
		fprintf(stderr, "shutdown: -H and -P flags can only be used along with -h flag.\n");
		usage();
  		exit(1);
	}

	/* Do we need to use the shutdown.allow file ? */
	if (useacl && (fp = fopen(SDALLOW, "r")) != NULL) {

		/* Read /etc/shutdown.allow. */
		i = 0;
		while(fgets(buf, 128, fp)) {
			if (buf[0] == '#' || buf[0] == '\n') continue;
			if (i > 31) continue;
			for(sp = buf; *sp; sp++) if (*sp == '\n') *sp = 0;
			downusers[i++] = strdup(buf);
		}
		if (i < 32) downusers[i] = 0;
		fclose(fp);

		/* Now walk through /var/run/utmp to find logged in users. */
		while(!user_ok && (ut = getutent()) != NULL) {

			/* See if this is a user process on a VC. */
			if (ut->ut_type != USER_PROCESS) continue;
			sprintf(term, "/dev/%.*s", UT_LINESIZE, ut->ut_line);
			if (stat(term, &st) < 0) continue;
#ifdef major /* glibc */
			if (major(st.st_rdev) != 4 ||
			    minor(st.st_rdev) > 63) continue;
#else
			if ((st.st_rdev & 0xFFC0) != 0x0400) continue;
#endif
			/* Root is always OK. */
			if (strcmp(ut->ut_user, "root") == 0) {
				user_ok++;
				break;
			}

			/* See if this is an allowed user. */
			for(i = 0; i < 32 && downusers[i]; i++)
				if (!strncmp(downusers[i], ut->ut_user,
				    UT_NAMESIZE)) {
					user_ok++;
					break;
				}
		}
		endutent();

		/* See if user was allowed. */
		if (!user_ok) {
			if ((fp = fopen(CONSOLE, "w")) != NULL) {
				fprintf(fp, "\rshutdown: no authorized users "
						"logged in.\r\n");
				fclose(fp);
			}
			exit(1);
		}
	}

	/* Read pid of running shutdown from a file */
	if ((fp = fopen(SDPID, "r")) != NULL) {
		if (fscanf(fp, "%d", &pid) != 1)
			pid = 0;
		fclose(fp);
	}

	/* Read remaining words, skip time if needed. */
	message[0] = 0;
	for(c = optind + (!cancel && !when); c < argc; c++) {
		if (strlen(message) + strlen(argv[c]) + 4 > MESSAGELEN)
			break;
  		strcat(message, argv[c]);
  		strcat(message, " ");
	}
	if (message[0]) strcat(message, "\r\n");

	/* See if we want to run or cancel. */
	if (cancel) {
		if (pid <= 0) {
			fprintf(stderr, "shutdown: cannot find pid "
					"of running shutdown.\n");
			exit(1);
		}
		init_setenv("INIT_HALT", NULL);
		if (kill(pid, SIGINT) < 0) {
			fprintf(stderr, "shutdown: not running.\n");
			exit(1);
		}
		if (message[0]) wall(message, 0);
		exit(0);
	}
  
	/* Check syntax. */
	if (when == NULL) {
		if (optind == argc) usage();
		when = argv[optind++];
	}

	/* See if we are already running. */
	if (pid > 0 && kill(pid, 0) == 0) {
		fprintf(stderr, "\rshutdown: already running.\r\n");
		exit(1);
	}

	/* Extra check. */
	if (doself && down_level[0] != '0' && down_level[0] != '6') {
		fprintf(stderr,
		"shutdown: can use \"-n\" for halt or reboot only.\r\n");
		exit(1);
	}

	/* Tell users what we're gonna do. */
	switch(down_level[0]) {
		case '0':
			strcpy(newstate, "for system halt");
			break;
		case '6':
			strcpy(newstate, "for reboot");
			break;
		case '1':
			strcpy(newstate, "to maintenance mode");
			break;
		default:
			sprintf(newstate, "to runlevel %s", down_level);
			break;
	}

	/* Go to the root directory */
	if (chdir("/")) {
		fprintf(stderr, "shutdown: chdir(/): %m\n");
		exit(1);
	}

	/* Create a new PID file. */
	unlink(SDPID);
	umask(022);
	if ((fp = fopen(SDPID, "w")) != NULL) {
		fprintf(fp, "%d\n", getpid());
		fclose(fp);
	} else if (errno != EROFS)
		fprintf(stderr, "shutdown: warning: cannot open %s\n", SDPID);

	/*
	 *	Catch some common signals.
	 */
	signal(SIGQUIT, SIG_IGN);
	signal(SIGCHLD, SIG_IGN);
	signal(SIGHUP,  SIG_IGN);
	signal(SIGTSTP, SIG_IGN);
	signal(SIGTTIN, SIG_IGN);
	signal(SIGTTOU, SIG_IGN);

	memset(&sa, 0, sizeof(sa));
	sa.sa_handler = stopit;
	sigaction(SIGINT, &sa, NULL);

	if (fastboot)  close(open(FASTBOOT,  O_CREAT | O_RDWR, 0644));
	if (forcefsck) close(open(FORCEFSCK, O_CREAT | O_RDWR, 0644));

	/* Alias now and take care of old '+mins' notation. */
	if (!strcmp(when, "now")) strcpy(when, "0");
	if (when[0] == '+') when++;

	/* Decode shutdown time. */
	for (sp = when; *sp; sp++) {
		if (*sp != ':' && (*sp < '0' || *sp > '9'))
			usage();
	}
	if (strchr(when, ':') == NULL) {
		/* Time in minutes. */
		wt = atoi(when);
		if (wt == 0 && when[0] != '0') usage();
	} else {
		/* Time in hh:mm format. */
		if (sscanf(when, "%d:%2d", &hours, &mins) != 2) usage();
		if (hours > 23 || mins > 59) usage();
		time(&t);
		lt = localtime(&t);
		wt = (60*hours + mins) - (60*lt->tm_hour + lt->tm_min);
		if (wt < 0) wt += 1440;
	}
	/* Shutdown NOW if time == 0 */
	if (wt == 0) issue_shutdown(halttype);

        /* Rather than loop and reduce wt (wait time) once per minute,
           we shall check the current time against the target time.
           Then calculate the remaining wating time based on the difference
           between current time and target time.
           This avoids missing shutdown time (target time) after the
           computer has been asleep. -- Jesse
        */
        /* target time, in seconds = current time + wait time */
        time(&t);
        target_time = t + (60 * wt); 

	/* Give warnings on regular intervals and finally shutdown. */
	if (wt < 15 && !needwarning(wt)) issue_warn(wt);
	while(wt) {
		if (wt <= 5 && !didnolog) {
			donologin(wt);
			didnolog++;
		}
		if (needwarning(wt)) issue_warn(wt);
		hardsleep(60);
                time(&t);    /* get current time once per minute */
                if (t >= target_time)     /* past the target */
                  wt = 0;
                else if ( (target_time - t) <= 60 )  /* less 1 min remains */
                {
                    hardsleep(target_time - t);
                    wt = 0;
                }
                else                      /* more thsn 1 min remains */
                   wt = (int) (target_time - t) / 60;
	}
	issue_shutdown(halttype);

	return 0; /* Never happens */
}