xref: /freebsd/sbin/shutdown/shutdown.c (revision 1db64f89363c97858961c4df0b7d02f3223723cf)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1988, 1990, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #include <sys/param.h>
33 #include <sys/boottrace.h>
34 #include <sys/resource.h>
35 #include <sys/syslog.h>
36 #include <sys/time.h>
37 
38 #include <ctype.h>
39 #include <err.h>
40 #include <errno.h>
41 #include <fcntl.h>
42 #include <paths.h>
43 #include <pwd.h>
44 #include <setjmp.h>
45 #include <signal.h>
46 #include <stdio.h>
47 #include <stdlib.h>
48 #include <string.h>
49 #include <unistd.h>
50 
51 #ifdef DEBUG
52 #undef _PATH_NOLOGIN
53 #define	_PATH_NOLOGIN	"./nologin"
54 #endif
55 
56 #define	H		*60*60
57 #define	M		*60
58 #define	S		*1
59 #define	NOLOG_TIME	5*60
60 static struct interval {
61 	int timeleft, timetowait;
62 } tlist[] = {
63 	{ 10 H,  5 H },
64 	{  5 H,  3 H },
65 	{  2 H,  1 H },
66 	{  1 H, 30 M },
67 	{ 30 M, 10 M },
68 	{ 20 M, 10 M },
69 	{ 10 M,  5 M },
70 	{  5 M,  3 M },
71 	{  2 M,  1 M },
72 	{  1 M, 30 S },
73 	{ 30 S, 30 S },
74 	{  0  ,  0   }
75 };
76 #undef H
77 #undef M
78 #undef S
79 
80 static time_t offset, shuttime;
81 static int docycle, dohalt, dopower, doreboot, killflg, mbuflen, oflag;
82 static char mbuf[BUFSIZ];
83 static const char *nosync, *whom;
84 
85 static void badtime(void);
86 static void die_you_gravy_sucking_pig_dog(void);
87 static void finish(int);
88 static void getoffset(char *);
89 static void loop(void);
90 static void nolog(void);
91 static void timeout(int);
92 static void timewarn(int);
93 static void usage(const char *);
94 
95 extern const char **environ;
96 
97 int
98 main(int argc, char **argv)
99 {
100 	char *p, *endp;
101 	struct passwd *pw;
102 	int arglen, ch, len, readstdin;
103 
104 #ifndef DEBUG
105 	if (geteuid())
106 		errx(1, "NOT super-user");
107 #endif
108 
109 	nosync = NULL;
110 	readstdin = 0;
111 
112 	/*
113 	 * Test for the special case where the utility is called as
114 	 * "poweroff", for which it runs 'shutdown -p now'.
115 	 */
116 	if ((p = strrchr(argv[0], '/')) == NULL)
117 		p = argv[0];
118 	else
119 		++p;
120 	if (strcmp(p, "poweroff") == 0) {
121 		if (getopt(argc, argv, "") != -1)
122 			usage((char *)NULL);
123 		argc -= optind;
124 		argv += optind;
125 		if (argc != 0)
126 			usage((char *)NULL);
127 		dopower = 1;
128 		offset = 0;
129 		(void)time(&shuttime);
130 		goto poweroff;
131 	}
132 
133 	while ((ch = getopt(argc, argv, "-chknopr")) != -1)
134 		switch (ch) {
135 		case '-':
136 			readstdin = 1;
137 			break;
138 		case 'c':
139 			docycle = 1;
140 			break;
141 		case 'h':
142 			dohalt = 1;
143 			break;
144 		case 'k':
145 			killflg = 1;
146 			break;
147 		case 'n':
148 			nosync = "-n";
149 			break;
150 		case 'o':
151 			oflag = 1;
152 			break;
153 		case 'p':
154 			dopower = 1;
155 			break;
156 		case 'r':
157 			doreboot = 1;
158 			break;
159 		case '?':
160 		default:
161 			usage((char *)NULL);
162 		}
163 	argc -= optind;
164 	argv += optind;
165 
166 	if (argc < 1)
167 		usage((char *)NULL);
168 
169 	if (killflg + doreboot + dohalt + dopower + docycle > 1)
170 		usage("incompatible switches -c, -h, -k, -p and -r");
171 
172 	if (oflag && !(dohalt || dopower || doreboot || docycle))
173 		usage("-o requires -c, -h, -p or -r");
174 
175 	if (nosync != NULL && !oflag)
176 		usage("-n requires -o");
177 
178 	getoffset(*argv++);
179 
180 poweroff:
181 	if (*argv) {
182 		for (p = mbuf, len = sizeof(mbuf); *argv; ++argv) {
183 			arglen = strlen(*argv);
184 			if ((len -= arglen) <= 2)
185 				break;
186 			if (p != mbuf)
187 				*p++ = ' ';
188 			memmove(p, *argv, arglen);
189 			p += arglen;
190 		}
191 		*p = '\n';
192 		*++p = '\0';
193 	}
194 
195 	if (readstdin) {
196 		p = mbuf;
197 		endp = mbuf + sizeof(mbuf) - 2;
198 		for (;;) {
199 			if (!fgets(p, endp - p + 1, stdin))
200 				break;
201 			for (; *p &&  p < endp; ++p);
202 			if (p == endp) {
203 				*p = '\n';
204 				*++p = '\0';
205 				break;
206 			}
207 		}
208 	}
209 	mbuflen = strlen(mbuf);
210 
211 	if (offset) {
212 		BOOTTRACE("Shutdown at %s", ctime(&shuttime));
213 		(void)printf("Shutdown at %.24s.\n", ctime(&shuttime));
214 	} else {
215 		BOOTTRACE("Shutdown NOW!");
216 		(void)printf("Shutdown NOW!\n");
217 	}
218 
219 	if (!(whom = getlogin()))
220 		whom = (pw = getpwuid(getuid())) ? pw->pw_name : "???";
221 
222 #ifdef DEBUG
223 	(void)putc('\n', stdout);
224 #else
225 	(void)setpriority(PRIO_PROCESS, 0, PRIO_MIN);
226 	{
227 		int forkpid;
228 
229 		forkpid = fork();
230 		if (forkpid == -1)
231 			err(1, "fork");
232 		if (forkpid)
233 			errx(0, "[pid %d]", forkpid);
234 	}
235 	setsid();
236 #endif
237 	openlog("shutdown", LOG_CONS, LOG_AUTH);
238 	loop();
239 	return(0);
240 }
241 
242 static void
243 loop(void)
244 {
245 	struct interval *tp;
246 	u_int sltime;
247 	int logged;
248 
249 	if (offset <= NOLOG_TIME) {
250 		logged = 1;
251 		nolog();
252 	}
253 	else
254 		logged = 0;
255 	tp = tlist;
256 	if (tp->timeleft < offset)
257 		(void)sleep((u_int)(offset - tp->timeleft));
258 	else {
259 		while (tp->timeleft && offset < tp->timeleft)
260 			++tp;
261 		/*
262 		 * Warn now, if going to sleep more than a fifth of
263 		 * the next wait time.
264 		 */
265 		if ((sltime = offset - tp->timeleft)) {
266 			if (sltime > (u_int)(tp->timetowait / 5))
267 				timewarn(offset);
268 			(void)sleep(sltime);
269 		}
270 	}
271 	for (;; ++tp) {
272 		timewarn(tp->timeleft);
273 		if (!logged && tp->timeleft <= NOLOG_TIME) {
274 			logged = 1;
275 			nolog();
276 		}
277 		(void)sleep((u_int)tp->timetowait);
278 		if (!tp->timeleft)
279 			break;
280 	}
281 	die_you_gravy_sucking_pig_dog();
282 }
283 
284 static jmp_buf alarmbuf;
285 
286 static const char *restricted_environ[] = {
287 	"PATH=" _PATH_STDPATH,
288 	NULL
289 };
290 
291 static void
292 timewarn(int timeleft)
293 {
294 	static int first;
295 	static char hostname[MAXHOSTNAMELEN + 1];
296 	FILE *pf;
297 	char wcmd[MAXPATHLEN + 4];
298 
299 	if (!first++)
300 		(void)gethostname(hostname, sizeof(hostname));
301 
302 	/* undoc -n option to wall suppresses normal wall banner */
303 	(void)snprintf(wcmd, sizeof(wcmd), "%s -n", _PATH_WALL);
304 	environ = restricted_environ;
305 	if (!(pf = popen(wcmd, "w"))) {
306 		syslog(LOG_ERR, "shutdown: can't find %s: %m", _PATH_WALL);
307 		return;
308 	}
309 
310 	(void)fprintf(pf,
311 	    "\007*** %sSystem shutdown message from %s@%s ***\007\n",
312 	    timeleft ? "": "FINAL ", whom, hostname);
313 
314 	if (timeleft > 10*60)
315 		(void)fprintf(pf, "System going down at %5.5s\n\n",
316 		    ctime(&shuttime) + 11);
317 	else if (timeleft > 59)
318 		(void)fprintf(pf, "System going down in %d minute%s\n\n",
319 		    timeleft / 60, (timeleft > 60) ? "s" : "");
320 	else if (timeleft)
321 		(void)fprintf(pf, "System going down in %s30 seconds\n\n",
322 		    (offset > 0 && offset < 30 ? "less than " : ""));
323 	else
324 		(void)fprintf(pf, "System going down IMMEDIATELY\n\n");
325 
326 	if (mbuflen)
327 		(void)fwrite(mbuf, sizeof(*mbuf), mbuflen, pf);
328 
329 	/*
330 	 * play some games, just in case wall doesn't come back
331 	 * probably unnecessary, given that wall is careful.
332 	 */
333 	if (!setjmp(alarmbuf)) {
334 		(void)signal(SIGALRM, timeout);
335 		(void)alarm((u_int)30);
336 		(void)pclose(pf);
337 		(void)alarm((u_int)0);
338 		(void)signal(SIGALRM, SIG_DFL);
339 	}
340 }
341 
342 static void
343 timeout(int signo __unused)
344 {
345 	longjmp(alarmbuf, 1);
346 }
347 
348 static void
349 die_you_gravy_sucking_pig_dog(void)
350 {
351 	char *empty_environ[] = { NULL };
352 
353 	BOOTTRACE("%s by %s",
354 	    doreboot ? "reboot" : dohalt ? "halt" : dopower ? "power-down" :
355 	    docycle ? "power-cycle" : "shutdown", whom);
356 	syslog(LOG_NOTICE, "%s by %s: %s",
357 	    doreboot ? "reboot" : dohalt ? "halt" : dopower ? "power-down" :
358 	    docycle ? "power-cycle" : "shutdown", whom, mbuf);
359 
360 	(void)printf("\r\nSystem shutdown time has arrived\007\007\r\n");
361 	if (killflg) {
362 		BOOTTRACE("fake shutdown...");
363 		(void)printf("\rbut you'll have to do it yourself\r\n");
364 		exit(0);
365 	}
366 #ifdef DEBUG
367 	if (doreboot)
368 		(void)printf("reboot");
369 	else if (docycle)
370 		(void)printf("power-cycle");
371 	else if (dohalt)
372 		(void)printf("halt");
373 	else if (dopower)
374 		(void)printf("power-down");
375 	if (nosync != NULL)
376 		(void)printf(" no sync");
377 	(void)printf("\nkill -HUP 1\n");
378 #else
379 	if (!oflag) {
380 		BOOTTRACE("signal to init(8)...");
381 		(void)kill(1, doreboot ? SIGINT :	/* reboot */
382 			      dohalt ? SIGUSR1 :	/* halt */
383 			      dopower ? SIGUSR2 :	/* power-down */
384 			      docycle ? SIGWINCH :	/* power-cycle */
385 			      SIGTERM);			/* single-user */
386 	} else {
387 		if (doreboot) {
388 			BOOTTRACE("exec reboot(8) -l...");
389 			execle(_PATH_REBOOT, "reboot", "-l", nosync,
390 				(char *)NULL, empty_environ);
391 			syslog(LOG_ERR, "shutdown: can't exec %s: %m.",
392 				_PATH_REBOOT);
393 			warn(_PATH_REBOOT);
394 		}
395 		else if (dohalt) {
396 			BOOTTRACE("exec halt(8) -l...");
397 			execle(_PATH_HALT, "halt", "-l", nosync,
398 				(char *)NULL, empty_environ);
399 			syslog(LOG_ERR, "shutdown: can't exec %s: %m.",
400 				_PATH_HALT);
401 			warn(_PATH_HALT);
402 		}
403 		else if (dopower) {
404 			BOOTTRACE("exec halt(8) -l -p...");
405 			execle(_PATH_HALT, "halt", "-l", "-p", nosync,
406 				(char *)NULL, empty_environ);
407 			syslog(LOG_ERR, "shutdown: can't exec %s: %m.",
408 				_PATH_HALT);
409 			warn(_PATH_HALT);
410 		}
411 		else if (docycle) {
412 			execle(_PATH_HALT, "halt", "-l", "-c", nosync,
413 				(char *)NULL, empty_environ);
414 			syslog(LOG_ERR, "shutdown: can't exec %s: %m.",
415 				_PATH_HALT);
416 			warn(_PATH_HALT);
417 		}
418 		BOOTTRACE("SIGTERM to init(8)...");
419 		(void)kill(1, SIGTERM);		/* to single-user */
420 	}
421 #endif
422 	finish(0);
423 }
424 
425 #define	ATOI2(p)	(p[0] - '0') * 10 + (p[1] - '0'); p += 2;
426 
427 static void
428 getoffset(char *timearg)
429 {
430 	struct tm *lt;
431 	char *p;
432 	time_t now;
433 	int maybe_today, this_year;
434 	char *timeunit;
435 
436 	(void)time(&now);
437 
438 	if (!strcasecmp(timearg, "now")) {		/* now */
439 		offset = 0;
440 		shuttime = now;
441 		return;
442 	}
443 
444 	if (*timearg == '+') {				/* +minutes */
445 		if (!isdigit(*++timearg))
446 			badtime();
447 		errno = 0;
448 		offset = strtol(timearg, &timeunit, 10);
449 		if (offset < 0 || offset == LONG_MAX || errno != 0)
450 			badtime();
451 		if (timeunit[0] == '\0' || strcasecmp(timeunit, "m") == 0 ||
452 		    strcasecmp(timeunit, "min") == 0 ||
453 		    strcasecmp(timeunit, "mins") == 0) {
454 			offset *= 60;
455 		} else if (strcasecmp(timeunit, "h") == 0 ||
456 		    strcasecmp(timeunit, "hour") == 0 ||
457 		    strcasecmp(timeunit, "hours") == 0) {
458 			offset *= 60 * 60;
459 		} else if (strcasecmp(timeunit, "s") == 0 ||
460 		    strcasecmp(timeunit, "sec") == 0 ||
461 		    strcasecmp(timeunit, "secs") == 0) {
462 			offset *= 1;
463 		} else {
464 			badtime();
465 		}
466 		shuttime = now + offset;
467 		return;
468 	}
469 
470 	/* handle hh:mm by getting rid of the colon */
471 	for (p = timearg; *p; ++p)
472 		if (!isascii(*p) || !isdigit(*p)) {
473 			if (*p == ':' && strlen(p) == 3) {
474 				p[0] = p[1];
475 				p[1] = p[2];
476 				p[2] = '\0';
477 			}
478 			else
479 				badtime();
480 		}
481 
482 	unsetenv("TZ");					/* OUR timezone */
483 	lt = localtime(&now);				/* current time val */
484 	maybe_today = 1;
485 
486 	switch(strlen(timearg)) {
487 	case 10:
488 		this_year = lt->tm_year;
489 		lt->tm_year = ATOI2(timearg);
490 		/*
491 		 * check if the specified year is in the next century.
492 		 * allow for one year of user error as many people will
493 		 * enter n - 1 at the start of year n.
494 		 */
495 		if (lt->tm_year < (this_year % 100) - 1)
496 			lt->tm_year += 100;
497 		/* adjust for the year 2000 and beyond */
498 		lt->tm_year += (this_year - (this_year % 100));
499 		/* FALLTHROUGH */
500 	case 8:
501 		lt->tm_mon = ATOI2(timearg);
502 		if (--lt->tm_mon < 0 || lt->tm_mon > 11)
503 			badtime();
504 		/* FALLTHROUGH */
505 	case 6:
506 		maybe_today = 0;
507 		lt->tm_mday = ATOI2(timearg);
508 		if (lt->tm_mday < 1 || lt->tm_mday > 31)
509 			badtime();
510 		/* FALLTHROUGH */
511 	case 4:
512 		lt->tm_hour = ATOI2(timearg);
513 		if (lt->tm_hour < 0 || lt->tm_hour > 23)
514 			badtime();
515 		lt->tm_min = ATOI2(timearg);
516 		if (lt->tm_min < 0 || lt->tm_min > 59)
517 			badtime();
518 		lt->tm_sec = 0;
519 		if ((shuttime = mktime(lt)) == -1)
520 			badtime();
521 
522 		if ((offset = shuttime - now) < 0) {
523 			if (!maybe_today)
524 				errx(1, "that time is already past.");
525 
526 			/*
527 			 * If the user only gave a time, assume that
528 			 * any time earlier than the current time
529 			 * was intended to be that time tomorrow.
530 			 */
531 			lt->tm_mday++;
532 			if ((shuttime = mktime(lt)) == -1)
533 				badtime();
534 			if ((offset = shuttime - now) < 0) {
535 				errx(1, "tomorrow is before today?");
536 			}
537 		}
538 		break;
539 	default:
540 		badtime();
541 	}
542 }
543 
544 #define	NOMSG	"\n\nNO LOGINS: System going down at "
545 static void
546 nolog(void)
547 {
548 	int logfd;
549 	char *ct;
550 
551 	(void)unlink(_PATH_NOLOGIN);	/* in case linked to another file */
552 	(void)signal(SIGINT, finish);
553 	(void)signal(SIGHUP, finish);
554 	(void)signal(SIGQUIT, finish);
555 	(void)signal(SIGTERM, finish);
556 	if ((logfd = open(_PATH_NOLOGIN, O_WRONLY|O_CREAT|O_TRUNC,
557 	    0664)) >= 0) {
558 		(void)write(logfd, NOMSG, sizeof(NOMSG) - 1);
559 		ct = ctime(&shuttime);
560 		(void)write(logfd, ct + 11, 5);
561 		(void)write(logfd, "\n\n", 2);
562 		(void)write(logfd, mbuf, strlen(mbuf));
563 		(void)close(logfd);
564 	}
565 }
566 
567 static void
568 finish(int signo __unused)
569 {
570 	if (!killflg)
571 		(void)unlink(_PATH_NOLOGIN);
572 	exit(0);
573 }
574 
575 static void
576 badtime(void)
577 {
578 	errx(1, "bad time format");
579 }
580 
581 static void
582 usage(const char *cp)
583 {
584 	if (cp != NULL)
585 		warnx("%s", cp);
586 	(void)fprintf(stderr,
587 	    "usage: shutdown [-] [-c | -h | -p | -r | -k] [-o [-n]] time [warning-message ...]\n"
588 	    "       poweroff\n");
589 	exit(1);
590 }
591