xref: /freebsd/sbin/init/init.c (revision daf1cffce2e07931f27c6c6998652e90df6ba87e)
1 /*-
2  * Copyright (c) 1991, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * This code is derived from software contributed to Berkeley by
6  * Donn Seeley at Berkeley Software Design, Inc.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. All advertising materials mentioning features or use of this software
17  *    must display the following acknowledgement:
18  *	This product includes software developed by the University of
19  *	California, Berkeley and its contributors.
20  * 4. Neither the name of the University nor the names of its contributors
21  *    may be used to endorse or promote products derived from this software
22  *    without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34  * SUCH DAMAGE.
35  */
36 
37 #ifndef lint
38 static const char copyright[] =
39 "@(#) Copyright (c) 1991, 1993\n\
40 	The Regents of the University of California.  All rights reserved.\n";
41 #endif /* not lint */
42 
43 #ifndef lint
44 #if 0
45 static char sccsid[] = "@(#)init.c	8.1 (Berkeley) 7/15/93";
46 #endif
47 static const char rcsid[] =
48   "$FreeBSD$";
49 #endif /* not lint */
50 
51 #include <sys/param.h>
52 #include <sys/ioctl.h>
53 #include <sys/mount.h>
54 #include <sys/sysctl.h>
55 #include <sys/wait.h>
56 #include <sys/types.h>
57 #include <sys/stat.h>
58 
59 #include <db.h>
60 #include <errno.h>
61 #include <fcntl.h>
62 #include <libutil.h>
63 #include <signal.h>
64 #include <stdio.h>
65 #include <stdlib.h>
66 #include <string.h>
67 #include <syslog.h>
68 #include <time.h>
69 #include <ttyent.h>
70 #include <unistd.h>
71 #include <sys/reboot.h>
72 #include <err.h>
73 
74 #ifdef __STDC__
75 #include <stdarg.h>
76 #else
77 #include <varargs.h>
78 #endif
79 
80 #ifdef SECURE
81 #include <pwd.h>
82 #endif
83 
84 #ifdef LOGIN_CAP
85 #include <login_cap.h>
86 #endif
87 
88 #include "pathnames.h"
89 
90 /*
91  * Sleep times; used to prevent thrashing.
92  */
93 #define	GETTY_SPACING		 5	/* N secs minimum getty spacing */
94 #define	GETTY_SLEEP		30	/* sleep N secs after spacing problem */
95 #define GETTY_NSPACE             3      /* max. spacing count to bring reaction */
96 #define	WINDOW_WAIT		 3	/* wait N secs after starting window */
97 #define	STALL_TIMEOUT		30	/* wait N secs after warning */
98 #define	DEATH_WATCH		10	/* wait N secs for procs to die */
99 #define DEATH_SCRIPT		120	/* wait for 2min for /etc/rc.shutdown */
100 #define RESOURCE_RC		"daemon"
101 #define RESOURCE_WINDOW 	"default"
102 #define RESOURCE_GETTY		"default"
103 
104 void handle __P((sig_t, ...));
105 void delset __P((sigset_t *, ...));
106 
107 void stall __P((char *, ...));
108 void warning __P((char *, ...));
109 void emergency __P((char *, ...));
110 void disaster __P((int));
111 void badsys __P((int));
112 int  runshutdown __P((void));
113 
114 /*
115  * We really need a recursive typedef...
116  * The following at least guarantees that the return type of (*state_t)()
117  * is sufficiently wide to hold a function pointer.
118  */
119 typedef long (*state_func_t) __P((void));
120 typedef state_func_t (*state_t) __P((void));
121 
122 state_func_t single_user __P((void));
123 state_func_t runcom __P((void));
124 state_func_t read_ttys __P((void));
125 state_func_t multi_user __P((void));
126 state_func_t clean_ttys __P((void));
127 state_func_t catatonia __P((void));
128 state_func_t death __P((void));
129 
130 enum { AUTOBOOT, FASTBOOT } runcom_mode = AUTOBOOT;
131 #define FALSE	0
132 #define TRUE	1
133 
134 int Reboot = FALSE;
135 int howto = RB_AUTOBOOT;
136 
137 int devfs;
138 
139 void transition __P((state_t));
140 state_t requested_transition = runcom;
141 
142 void setctty __P((char *));
143 
144 typedef struct init_session {
145 	int	se_index;		/* index of entry in ttys file */
146 	pid_t	se_process;		/* controlling process */
147 	time_t	se_started;		/* used to avoid thrashing */
148 	int	se_flags;		/* status of session */
149 #define	SE_SHUTDOWN	0x1		/* session won't be restarted */
150 #define	SE_PRESENT	0x2		/* session is in /etc/ttys */
151 	int     se_nspace;              /* spacing count */
152 	char	*se_device;		/* filename of port */
153 	char	*se_getty;		/* what to run on that port */
154 	char    *se_getty_argv_space;   /* pre-parsed argument array space */
155 	char	**se_getty_argv;	/* pre-parsed argument array */
156 	char	*se_window;		/* window system (started only once) */
157 	char    *se_window_argv_space;  /* pre-parsed argument array space */
158 	char	**se_window_argv;	/* pre-parsed argument array */
159 	char    *se_type;               /* default terminal type */
160 	struct	init_session *se_prev;
161 	struct	init_session *se_next;
162 } session_t;
163 
164 void free_session __P((session_t *));
165 session_t *new_session __P((session_t *, int, struct ttyent *));
166 session_t *sessions;
167 
168 char **construct_argv __P((char *));
169 void start_window_system __P((session_t *));
170 void collect_child __P((pid_t));
171 pid_t start_getty __P((session_t *));
172 void transition_handler __P((int));
173 void alrm_handler __P((int));
174 void setsecuritylevel __P((int));
175 int getsecuritylevel __P((void));
176 int setupargv __P((session_t *, struct ttyent *));
177 #ifdef LOGIN_CAP
178 void setprocresources __P((const char *));
179 #endif
180 int clang;
181 
182 void clear_session_logs __P((session_t *));
183 
184 int start_session_db __P((void));
185 void add_session __P((session_t *));
186 void del_session __P((session_t *));
187 session_t *find_session __P((pid_t));
188 DB *session_db;
189 
190 /*
191  * The mother of all processes.
192  */
193 int
194 main(argc, argv)
195 	int argc;
196 	char **argv;
197 {
198 	int c;
199 	struct sigaction sa;
200 	sigset_t mask;
201 
202 
203 	/* Dispose of random users. */
204 	if (getuid() != 0)
205 		errx(1, "%s", strerror(EPERM));
206 
207 	/* System V users like to reexec init. */
208 	if (getpid() != 1) {
209 #ifdef COMPAT_SYSV_INIT
210 		/* So give them what they want */
211 		if (argc > 1) {
212 			if (strlen(argv[1]) == 1) {
213 				register char runlevel = *argv[1];
214 				register int sig;
215 
216 				switch (runlevel) {
217 					case '0': /* halt + poweroff */
218 						sig = SIGUSR2;
219 						break;
220 					case '1': /* single-user */
221 						sig = SIGTERM;
222 						break;
223 					case '6': /* reboot */
224 						sig = SIGINT;
225 						break;
226 					case 'c': /* block further logins */
227 						sig = SIGTSTP;
228 						break;
229 					case 'q': /* rescan /etc/ttys */
230 						sig = SIGHUP;
231 						break;
232 					default:
233 						goto invalid;
234 				}
235 				kill(1, sig);
236 				_exit(0);
237 			} else
238 invalid:
239 				errx(1, "invalid run-level ``%s''", argv[1]);
240 		} else
241 #endif
242 			errx(1, "already running");
243 	}
244 	/*
245 	 * Note that this does NOT open a file...
246 	 * Does 'init' deserve its own facility number?
247 	 */
248 	openlog("init", LOG_CONS|LOG_ODELAY, LOG_AUTH);
249 
250 	/*
251 	 * Create an initial session.
252 	 */
253 	if (setsid() < 0)
254 		warning("initial setsid() failed: %m");
255 
256 	/*
257 	 * Establish an initial user so that programs running
258 	 * single user do not freak out and die (like passwd).
259 	 */
260 	if (setlogin("root") < 0)
261 		warning("setlogin() failed: %m");
262 
263 	/*
264 	 * This code assumes that we always get arguments through flags,
265 	 * never through bits set in some random machine register.
266 	 */
267 	while ((c = getopt(argc, argv, "dsf")) != -1)
268 		switch (c) {
269 		case 'd':
270 			devfs = 1;
271 			break;
272 		case 's':
273 			requested_transition = single_user;
274 			break;
275 		case 'f':
276 			runcom_mode = FASTBOOT;
277 			break;
278 		default:
279 			warning("unrecognized flag '-%c'", c);
280 			break;
281 		}
282 
283 	if (optind != argc)
284 		warning("ignoring excess arguments");
285 
286 	if (devfs) {
287 		mount("devfs", "/dev", MNT_NOEXEC|MNT_RDONLY, 0);
288 	}
289 
290 	/*
291 	 * We catch or block signals rather than ignore them,
292 	 * so that they get reset on exec.
293 	 */
294 	handle(badsys, SIGSYS, 0);
295 	handle(disaster, SIGABRT, SIGFPE, SIGILL, SIGSEGV,
296 	       SIGBUS, SIGXCPU, SIGXFSZ, 0);
297 	handle(transition_handler, SIGHUP, SIGINT, SIGTERM, SIGTSTP,
298 		SIGUSR1, SIGUSR2, 0);
299 	handle(alrm_handler, SIGALRM, 0);
300 	sigfillset(&mask);
301 	delset(&mask, SIGABRT, SIGFPE, SIGILL, SIGSEGV, SIGBUS, SIGSYS,
302 		SIGXCPU, SIGXFSZ, SIGHUP, SIGINT, SIGTERM, SIGTSTP, SIGALRM,
303 		SIGUSR1, SIGUSR2, 0);
304 	sigprocmask(SIG_SETMASK, &mask, (sigset_t *) 0);
305 	sigemptyset(&sa.sa_mask);
306 	sa.sa_flags = 0;
307 	sa.sa_handler = SIG_IGN;
308 	(void) sigaction(SIGTTIN, &sa, (struct sigaction *)0);
309 	(void) sigaction(SIGTTOU, &sa, (struct sigaction *)0);
310 
311 	/*
312 	 * Paranoia.
313 	 */
314 	close(0);
315 	close(1);
316 	close(2);
317 
318 	/*
319 	 * Start the state machine.
320 	 */
321 	transition(requested_transition);
322 
323 	/*
324 	 * Should never reach here.
325 	 */
326 	return 1;
327 }
328 
329 /*
330  * Associate a function with a signal handler.
331  */
332 void
333 #ifdef __STDC__
334 handle(sig_t handler, ...)
335 #else
336 handle(va_alist)
337 	va_dcl
338 #endif
339 {
340 	int sig;
341 	struct sigaction sa;
342 	sigset_t mask_everything;
343 	va_list ap;
344 #ifndef __STDC__
345 	sig_t handler;
346 
347 	va_start(ap);
348 	handler = va_arg(ap, sig_t);
349 #else
350 	va_start(ap, handler);
351 #endif
352 
353 	sa.sa_handler = handler;
354 	sigfillset(&mask_everything);
355 
356 	while ((sig = va_arg(ap, int)) != NULL) {
357 		sa.sa_mask = mask_everything;
358 		/* XXX SA_RESTART? */
359 		sa.sa_flags = sig == SIGCHLD ? SA_NOCLDSTOP : 0;
360 		sigaction(sig, &sa, (struct sigaction *) 0);
361 	}
362 	va_end(ap);
363 }
364 
365 /*
366  * Delete a set of signals from a mask.
367  */
368 void
369 #ifdef __STDC__
370 delset(sigset_t *maskp, ...)
371 #else
372 delset(va_alist)
373 	va_dcl
374 #endif
375 {
376 	int sig;
377 	va_list ap;
378 #ifndef __STDC__
379 	sigset_t *maskp;
380 
381 	va_start(ap);
382 	maskp = va_arg(ap, sigset_t *);
383 #else
384 	va_start(ap, maskp);
385 #endif
386 
387 	while ((sig = va_arg(ap, int)) != NULL)
388 		sigdelset(maskp, sig);
389 	va_end(ap);
390 }
391 
392 /*
393  * Log a message and sleep for a while (to give someone an opportunity
394  * to read it and to save log or hardcopy output if the problem is chronic).
395  * NB: should send a message to the session logger to avoid blocking.
396  */
397 void
398 #ifdef __STDC__
399 stall(char *message, ...)
400 #else
401 stall(va_alist)
402 	va_dcl
403 #endif
404 {
405 	va_list ap;
406 #ifndef __STDC__
407 	char *message;
408 
409 	va_start(ap);
410 	message = va_arg(ap, char *);
411 #else
412 	va_start(ap, message);
413 #endif
414 
415 	vsyslog(LOG_ALERT, message, ap);
416 	va_end(ap);
417 	sleep(STALL_TIMEOUT);
418 }
419 
420 /*
421  * Like stall(), but doesn't sleep.
422  * If cpp had variadic macros, the two functions could be #defines for another.
423  * NB: should send a message to the session logger to avoid blocking.
424  */
425 void
426 #ifdef __STDC__
427 warning(char *message, ...)
428 #else
429 warning(va_alist)
430 	va_dcl
431 #endif
432 {
433 	va_list ap;
434 #ifndef __STDC__
435 	char *message;
436 
437 	va_start(ap);
438 	message = va_arg(ap, char *);
439 #else
440 	va_start(ap, message);
441 #endif
442 
443 	vsyslog(LOG_ALERT, message, ap);
444 	va_end(ap);
445 }
446 
447 /*
448  * Log an emergency message.
449  * NB: should send a message to the session logger to avoid blocking.
450  */
451 void
452 #ifdef __STDC__
453 emergency(char *message, ...)
454 #else
455 emergency(va_alist)
456 	va_dcl
457 #endif
458 {
459 	va_list ap;
460 #ifndef __STDC__
461 	char *message;
462 
463 	va_start(ap);
464 	message = va_arg(ap, char *);
465 #else
466 	va_start(ap, message);
467 #endif
468 
469 	vsyslog(LOG_EMERG, message, ap);
470 	va_end(ap);
471 }
472 
473 /*
474  * Catch a SIGSYS signal.
475  *
476  * These may arise if a system does not support sysctl.
477  * We tolerate up to 25 of these, then throw in the towel.
478  */
479 void
480 badsys(sig)
481 	int sig;
482 {
483 	static int badcount = 0;
484 
485 	if (badcount++ < 25)
486 		return;
487 	disaster(sig);
488 }
489 
490 /*
491  * Catch an unexpected signal.
492  */
493 void
494 disaster(sig)
495 	int sig;
496 {
497 	emergency("fatal signal: %s",
498 		(unsigned)sig < NSIG ? sys_siglist[sig] : "unknown signal");
499 
500 	sleep(STALL_TIMEOUT);
501 	_exit(sig);		/* reboot */
502 }
503 
504 /*
505  * Get the security level of the kernel.
506  */
507 int
508 getsecuritylevel()
509 {
510 #ifdef KERN_SECURELVL
511 	int name[2], curlevel;
512 	size_t len;
513 	extern int errno;
514 
515 	name[0] = CTL_KERN;
516 	name[1] = KERN_SECURELVL;
517 	len = sizeof curlevel;
518 	if (sysctl(name, 2, &curlevel, &len, NULL, 0) == -1) {
519 		emergency("cannot get kernel security level: %s",
520 		    strerror(errno));
521 		return (-1);
522 	}
523 	return (curlevel);
524 #else
525 	return (-1);
526 #endif
527 }
528 
529 /*
530  * Set the security level of the kernel.
531  */
532 void
533 setsecuritylevel(newlevel)
534 	int newlevel;
535 {
536 #ifdef KERN_SECURELVL
537 	int name[2], curlevel;
538 	extern int errno;
539 
540 	curlevel = getsecuritylevel();
541 	if (newlevel == curlevel)
542 		return;
543 	name[0] = CTL_KERN;
544 	name[1] = KERN_SECURELVL;
545 	if (sysctl(name, 2, NULL, NULL, &newlevel, sizeof newlevel) == -1) {
546 		emergency(
547 		    "cannot change kernel security level from %d to %d: %s",
548 		    curlevel, newlevel, strerror(errno));
549 		return;
550 	}
551 #ifdef SECURE
552 	warning("kernel security level changed from %d to %d",
553 	    curlevel, newlevel);
554 #endif
555 #endif
556 }
557 
558 /*
559  * Change states in the finite state machine.
560  * The initial state is passed as an argument.
561  */
562 void
563 transition(s)
564 	state_t s;
565 {
566 	for (;;)
567 		s = (state_t) (*s)();
568 }
569 
570 /*
571  * Close out the accounting files for a login session.
572  * NB: should send a message to the session logger to avoid blocking.
573  */
574 void
575 clear_session_logs(sp)
576 	session_t *sp;
577 {
578 	char *line = sp->se_device + sizeof(_PATH_DEV) - 1;
579 
580 	if (logout(line))
581 		logwtmp(line, "", "");
582 }
583 
584 /*
585  * Start a session and allocate a controlling terminal.
586  * Only called by children of init after forking.
587  */
588 void
589 setctty(name)
590 	char *name;
591 {
592 	int fd;
593 
594 	(void) revoke(name);
595 	if ((fd = open(name, O_RDWR)) == -1) {
596 		stall("can't open %s: %m", name);
597 		_exit(1);
598 	}
599 	if (login_tty(fd) == -1) {
600 		stall("can't get %s for controlling terminal: %m", name);
601 		_exit(1);
602 	}
603 }
604 
605 /*
606  * Bring the system up single user.
607  */
608 state_func_t
609 single_user()
610 {
611 	pid_t pid, wpid;
612 	int status;
613 	sigset_t mask;
614 	char *shell = _PATH_BSHELL;
615 	char *argv[2];
616 #ifdef SECURE
617 	struct ttyent *typ;
618 	struct passwd *pp;
619 	static const char banner[] =
620 		"Enter root password, or ^D to go multi-user\n";
621 	char *clear, *password;
622 #endif
623 #ifdef DEBUGSHELL
624 	char altshell[128];
625 #endif
626 
627 	if (Reboot) {
628 		/* Instead of going single user, let's reboot the machine */
629 		sync();
630 		alarm(2);
631 		pause();
632 		reboot(howto);
633 		_exit(0);
634 	}
635 
636 	if ((pid = fork()) == 0) {
637 		/*
638 		 * Start the single user session.
639 		 */
640 		setctty(_PATH_CONSOLE);
641 
642 #ifdef SECURE
643 		/*
644 		 * Check the root password.
645 		 * We don't care if the console is 'on' by default;
646 		 * it's the only tty that can be 'off' and 'secure'.
647 		 */
648 		typ = getttynam("console");
649 		pp = getpwnam("root");
650 		if (typ && (typ->ty_status & TTY_SECURE) == 0 &&
651 		    pp && *pp->pw_passwd) {
652 			write(2, banner, sizeof banner - 1);
653 			for (;;) {
654 				clear = getpass("Password:");
655 				if (clear == 0 || *clear == '\0')
656 					_exit(0);
657 				password = crypt(clear, pp->pw_passwd);
658 				bzero(clear, _PASSWORD_LEN);
659 				if (strcmp(password, pp->pw_passwd) == 0)
660 					break;
661 				warning("single-user login failed\n");
662 			}
663 		}
664 		endttyent();
665 		endpwent();
666 #endif /* SECURE */
667 
668 #ifdef DEBUGSHELL
669 		{
670 			char *cp = altshell;
671 			int num;
672 
673 #define	SHREQUEST \
674 	"Enter full pathname of shell or RETURN for " _PATH_BSHELL ": "
675 			(void)write(STDERR_FILENO,
676 			    SHREQUEST, sizeof(SHREQUEST) - 1);
677 			while ((num = read(STDIN_FILENO, cp, 1)) != -1 &&
678 			    num != 0 && *cp != '\n' && cp < &altshell[127])
679 					cp++;
680 			*cp = '\0';
681 			if (altshell[0] != '\0')
682 				shell = altshell;
683 		}
684 #endif /* DEBUGSHELL */
685 
686 		/*
687 		 * Unblock signals.
688 		 * We catch all the interesting ones,
689 		 * and those are reset to SIG_DFL on exec.
690 		 */
691 		sigemptyset(&mask);
692 		sigprocmask(SIG_SETMASK, &mask, (sigset_t *) 0);
693 
694 		/*
695 		 * Fire off a shell.
696 		 * If the default one doesn't work, try the Bourne shell.
697 		 */
698 		argv[0] = "-sh";
699 		argv[1] = 0;
700 		execv(shell, argv);
701 		emergency("can't exec %s for single user: %m", shell);
702 		execv(_PATH_BSHELL, argv);
703 		emergency("can't exec %s for single user: %m", _PATH_BSHELL);
704 		sleep(STALL_TIMEOUT);
705 		_exit(1);
706 	}
707 
708 	if (pid == -1) {
709 		/*
710 		 * We are seriously hosed.  Do our best.
711 		 */
712 		emergency("can't fork single-user shell, trying again");
713 		while (waitpid(-1, (int *) 0, WNOHANG) > 0)
714 			continue;
715 		return (state_func_t) single_user;
716 	}
717 
718 	requested_transition = 0;
719 	do {
720 		if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1)
721 			collect_child(wpid);
722 		if (wpid == -1) {
723 			if (errno == EINTR)
724 				continue;
725 			warning("wait for single-user shell failed: %m; restarting");
726 			return (state_func_t) single_user;
727 		}
728 		if (wpid == pid && WIFSTOPPED(status)) {
729 			warning("init: shell stopped, restarting\n");
730 			kill(pid, SIGCONT);
731 			wpid = -1;
732 		}
733 	} while (wpid != pid && !requested_transition);
734 
735 	if (requested_transition)
736 		return (state_func_t) requested_transition;
737 
738 	if (!WIFEXITED(status)) {
739 		if (WTERMSIG(status) == SIGKILL) {
740 			/*
741 			 *  reboot(8) killed shell?
742 			 */
743 			warning("single user shell terminated.");
744 			sleep(STALL_TIMEOUT);
745 			_exit(0);
746 		} else {
747 			warning("single user shell terminated, restarting");
748 			return (state_func_t) single_user;
749 		}
750 	}
751 
752 	runcom_mode = FASTBOOT;
753 	return (state_func_t) runcom;
754 }
755 
756 /*
757  * Run the system startup script.
758  */
759 state_func_t
760 runcom()
761 {
762 	pid_t pid, wpid;
763 	int status;
764 	char *argv[4];
765 	struct sigaction sa;
766 
767 	if ((pid = fork()) == 0) {
768 		sigemptyset(&sa.sa_mask);
769 		sa.sa_flags = 0;
770 		sa.sa_handler = SIG_IGN;
771 		(void) sigaction(SIGTSTP, &sa, (struct sigaction *)0);
772 		(void) sigaction(SIGHUP, &sa, (struct sigaction *)0);
773 
774 		setctty(_PATH_CONSOLE);
775 
776 		argv[0] = "sh";
777 		argv[1] = _PATH_RUNCOM;
778 		argv[2] = runcom_mode == AUTOBOOT ? "autoboot" : 0;
779 		argv[3] = 0;
780 
781 		sigprocmask(SIG_SETMASK, &sa.sa_mask, (sigset_t *) 0);
782 
783 #ifdef LOGIN_CAP
784 		setprocresources(RESOURCE_RC);
785 #endif
786 		execv(_PATH_BSHELL, argv);
787 		stall("can't exec %s for %s: %m", _PATH_BSHELL, _PATH_RUNCOM);
788 		_exit(1);	/* force single user mode */
789 	}
790 
791 	if (pid == -1) {
792 		emergency("can't fork for %s on %s: %m",
793 			_PATH_BSHELL, _PATH_RUNCOM);
794 		while (waitpid(-1, (int *) 0, WNOHANG) > 0)
795 			continue;
796 		sleep(STALL_TIMEOUT);
797 		return (state_func_t) single_user;
798 	}
799 
800 	/*
801 	 * Copied from single_user().  This is a bit paranoid.
802 	 */
803 	do {
804 		if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1)
805 			collect_child(wpid);
806 		if (wpid == -1) {
807 			if (errno == EINTR)
808 				continue;
809 			warning("wait for %s on %s failed: %m; going to single user mode",
810 				_PATH_BSHELL, _PATH_RUNCOM);
811 			return (state_func_t) single_user;
812 		}
813 		if (wpid == pid && WIFSTOPPED(status)) {
814 			warning("init: %s on %s stopped, restarting\n",
815 				_PATH_BSHELL, _PATH_RUNCOM);
816 			kill(pid, SIGCONT);
817 			wpid = -1;
818 		}
819 	} while (wpid != pid);
820 
821 	if (WIFSIGNALED(status) && WTERMSIG(status) == SIGTERM &&
822 	    requested_transition == catatonia) {
823 		/* /etc/rc executed /sbin/reboot; wait for the end quietly */
824 		sigset_t s;
825 
826 		sigfillset(&s);
827 		for (;;)
828 			sigsuspend(&s);
829 	}
830 
831 	if (!WIFEXITED(status)) {
832 		warning("%s on %s terminated abnormally, going to single user mode",
833 			_PATH_BSHELL, _PATH_RUNCOM);
834 		return (state_func_t) single_user;
835 	}
836 
837 	if (WEXITSTATUS(status))
838 		return (state_func_t) single_user;
839 
840 	runcom_mode = AUTOBOOT;		/* the default */
841 	/* NB: should send a message to the session logger to avoid blocking. */
842 	logwtmp("~", "reboot", "");
843 	return (state_func_t) read_ttys;
844 }
845 
846 /*
847  * Open the session database.
848  *
849  * NB: We could pass in the size here; is it necessary?
850  */
851 int
852 start_session_db()
853 {
854 	if (session_db && (*session_db->close)(session_db))
855 		emergency("session database close: %s", strerror(errno));
856 	if ((session_db = dbopen(NULL, O_RDWR, 0, DB_HASH, NULL)) == 0) {
857 		emergency("session database open: %s", strerror(errno));
858 		return (1);
859 	}
860 	return (0);
861 
862 }
863 
864 /*
865  * Add a new login session.
866  */
867 void
868 add_session(sp)
869 	session_t *sp;
870 {
871 	DBT key;
872 	DBT data;
873 
874 	key.data = &sp->se_process;
875 	key.size = sizeof sp->se_process;
876 	data.data = &sp;
877 	data.size = sizeof sp;
878 
879 	if ((*session_db->put)(session_db, &key, &data, 0))
880 		emergency("insert %d: %s", sp->se_process, strerror(errno));
881 }
882 
883 /*
884  * Delete an old login session.
885  */
886 void
887 del_session(sp)
888 	session_t *sp;
889 {
890 	DBT key;
891 
892 	key.data = &sp->se_process;
893 	key.size = sizeof sp->se_process;
894 
895 	if ((*session_db->del)(session_db, &key, 0))
896 		emergency("delete %d: %s", sp->se_process, strerror(errno));
897 }
898 
899 /*
900  * Look up a login session by pid.
901  */
902 session_t *
903 #ifdef __STDC__
904 find_session(pid_t pid)
905 #else
906 find_session(pid)
907 	pid_t pid;
908 #endif
909 {
910 	DBT key;
911 	DBT data;
912 	session_t *ret;
913 
914 	key.data = &pid;
915 	key.size = sizeof pid;
916 	if ((*session_db->get)(session_db, &key, &data, 0) != 0)
917 		return 0;
918 	bcopy(data.data, (char *)&ret, sizeof(ret));
919 	return ret;
920 }
921 
922 /*
923  * Construct an argument vector from a command line.
924  */
925 char **
926 construct_argv(command)
927 	char *command;
928 {
929 	char *strk (char *);
930 	register int argc = 0;
931 	register char **argv = (char **) malloc(((strlen(command) + 1) / 2 + 1)
932 						* sizeof (char *));
933 
934 	if ((argv[argc++] = strk(command)) == 0) {
935 		free(argv);
936 		return (NULL);
937 	}
938 	while ((argv[argc++] = strk((char *) 0)) != NULL)
939 		continue;
940 	return argv;
941 }
942 
943 /*
944  * Deallocate a session descriptor.
945  */
946 void
947 free_session(sp)
948 	register session_t *sp;
949 {
950 	free(sp->se_device);
951 	if (sp->se_getty) {
952 		free(sp->se_getty);
953 		free(sp->se_getty_argv_space);
954 		free(sp->se_getty_argv);
955 	}
956 	if (sp->se_window) {
957 		free(sp->se_window);
958 		free(sp->se_window_argv_space);
959 		free(sp->se_window_argv);
960 	}
961 	if (sp->se_type)
962 		free(sp->se_type);
963 	free(sp);
964 }
965 
966 /*
967  * Allocate a new session descriptor.
968  * Mark it SE_PRESENT.
969  */
970 session_t *
971 new_session(sprev, session_index, typ)
972 	session_t *sprev;
973 	int session_index;
974 	register struct ttyent *typ;
975 {
976 	register session_t *sp;
977 	int fd;
978 
979 	if ((typ->ty_status & TTY_ON) == 0 ||
980 	    typ->ty_name == 0 ||
981 	    typ->ty_getty == 0)
982 		return 0;
983 
984 	sp = (session_t *) calloc(1, sizeof (session_t));
985 
986 	sp->se_index = session_index;
987 	sp->se_flags |= SE_PRESENT;
988 
989 	sp->se_device = malloc(sizeof(_PATH_DEV) + strlen(typ->ty_name));
990 	(void) sprintf(sp->se_device, "%s%s", _PATH_DEV, typ->ty_name);
991 
992 	/*
993 	 * Attempt to open the device, if we get "device not configured"
994 	 * then don't add the device to the session list.
995 	 */
996 	if ((fd = open(sp->se_device, O_RDONLY | O_NONBLOCK, 0)) < 0) {
997 		if (errno == ENXIO) {
998 			free_session(sp);
999 			return (0);
1000 		}
1001 	} else
1002 		close(fd);
1003 
1004 	if (setupargv(sp, typ) == 0) {
1005 		free_session(sp);
1006 		return (0);
1007 	}
1008 
1009 	sp->se_next = 0;
1010 	if (sprev == 0) {
1011 		sessions = sp;
1012 		sp->se_prev = 0;
1013 	} else {
1014 		sprev->se_next = sp;
1015 		sp->se_prev = sprev;
1016 	}
1017 
1018 	return sp;
1019 }
1020 
1021 /*
1022  * Calculate getty and if useful window argv vectors.
1023  */
1024 int
1025 setupargv(sp, typ)
1026 	session_t *sp;
1027 	struct ttyent *typ;
1028 {
1029 
1030 	if (sp->se_getty) {
1031 		free(sp->se_getty);
1032 		free(sp->se_getty_argv_space);
1033 		free(sp->se_getty_argv);
1034 	}
1035 	sp->se_getty = malloc(strlen(typ->ty_getty) + strlen(typ->ty_name) + 2);
1036 	(void) sprintf(sp->se_getty, "%s %s", typ->ty_getty, typ->ty_name);
1037 	sp->se_getty_argv_space = strdup(sp->se_getty);
1038 	sp->se_getty_argv = construct_argv(sp->se_getty_argv_space);
1039 	if (sp->se_getty_argv == 0) {
1040 		warning("can't parse getty for port %s", sp->se_device);
1041 		free(sp->se_getty);
1042 		free(sp->se_getty_argv_space);
1043 		sp->se_getty = sp->se_getty_argv_space = 0;
1044 		return (0);
1045 	}
1046 	if (sp->se_window) {
1047 		free(sp->se_window);
1048 		free(sp->se_window_argv_space);
1049 		free(sp->se_window_argv);
1050 	}
1051 	sp->se_window = sp->se_window_argv_space = 0;
1052 	sp->se_window_argv = 0;
1053 	if (typ->ty_window) {
1054 		sp->se_window = strdup(typ->ty_window);
1055 		sp->se_window_argv_space = strdup(sp->se_window);
1056 		sp->se_window_argv = construct_argv(sp->se_window_argv_space);
1057 		if (sp->se_window_argv == 0) {
1058 			warning("can't parse window for port %s",
1059 				sp->se_device);
1060 			free(sp->se_window_argv_space);
1061 			free(sp->se_window);
1062 			sp->se_window = sp->se_window_argv_space = 0;
1063 			return (0);
1064 		}
1065 	}
1066 	if (sp->se_type)
1067 		free(sp->se_type);
1068 	sp->se_type = typ->ty_type ? strdup(typ->ty_type) : 0;
1069 	return (1);
1070 }
1071 
1072 /*
1073  * Walk the list of ttys and create sessions for each active line.
1074  */
1075 state_func_t
1076 read_ttys()
1077 {
1078 	int session_index = 0;
1079 	register session_t *sp, *snext;
1080 	register struct ttyent *typ;
1081 
1082 	/*
1083 	 * Destroy any previous session state.
1084 	 * There shouldn't be any, but just in case...
1085 	 */
1086 	for (sp = sessions; sp; sp = snext) {
1087 		if (sp->se_process)
1088 			clear_session_logs(sp);
1089 		snext = sp->se_next;
1090 		free_session(sp);
1091 	}
1092 	sessions = 0;
1093 	if (start_session_db())
1094 		return (state_func_t) single_user;
1095 
1096 	/*
1097 	 * Allocate a session entry for each active port.
1098 	 * Note that sp starts at 0.
1099 	 */
1100 	while ((typ = getttyent()) != NULL)
1101 		if ((snext = new_session(sp, ++session_index, typ)) != NULL)
1102 			sp = snext;
1103 
1104 	endttyent();
1105 
1106 	return (state_func_t) multi_user;
1107 }
1108 
1109 /*
1110  * Start a window system running.
1111  */
1112 void
1113 start_window_system(sp)
1114 	session_t *sp;
1115 {
1116 	pid_t pid;
1117 	sigset_t mask;
1118 	char term[64], *env[2];
1119 
1120 	if ((pid = fork()) == -1) {
1121 		emergency("can't fork for window system on port %s: %m",
1122 			sp->se_device);
1123 		/* hope that getty fails and we can try again */
1124 		return;
1125 	}
1126 
1127 	if (pid)
1128 		return;
1129 
1130 	sigemptyset(&mask);
1131 	sigprocmask(SIG_SETMASK, &mask, (sigset_t *) 0);
1132 
1133 	if (setsid() < 0)
1134 		emergency("setsid failed (window) %m");
1135 
1136 #ifdef LOGIN_CAP
1137 	setprocresources(RESOURCE_WINDOW);
1138 #endif
1139 	if (sp->se_type) {
1140 		/* Don't use malloc after fork */
1141 		strcpy(term, "TERM=");
1142 		strncat(term, sp->se_type, sizeof(term) - 6);
1143 		env[0] = term;
1144 		env[1] = 0;
1145 	}
1146 	else
1147 		env[0] = 0;
1148 	execve(sp->se_window_argv[0], sp->se_window_argv, env);
1149 	stall("can't exec window system '%s' for port %s: %m",
1150 		sp->se_window_argv[0], sp->se_device);
1151 	_exit(1);
1152 }
1153 
1154 /*
1155  * Start a login session running.
1156  */
1157 pid_t
1158 start_getty(sp)
1159 	session_t *sp;
1160 {
1161 	pid_t pid;
1162 	sigset_t mask;
1163 	time_t current_time = time((time_t *) 0);
1164 	int too_quick = 0;
1165 	char term[64], *env[2];
1166 
1167 	if (current_time >= sp->se_started &&
1168 	    current_time - sp->se_started < GETTY_SPACING) {
1169 		if (++sp->se_nspace > GETTY_NSPACE) {
1170 			sp->se_nspace = 0;
1171 			too_quick = 1;
1172 		}
1173 	} else
1174 		sp->se_nspace = 0;
1175 
1176 	/*
1177 	 * fork(), not vfork() -- we can't afford to block.
1178 	 */
1179 	if ((pid = fork()) == -1) {
1180 		emergency("can't fork for getty on port %s: %m", sp->se_device);
1181 		return -1;
1182 	}
1183 
1184 	if (pid)
1185 		return pid;
1186 
1187 	if (too_quick) {
1188 		warning("getty repeating too quickly on port %s, sleeping %d secs",
1189 			sp->se_device, GETTY_SLEEP);
1190 		sleep((unsigned) GETTY_SLEEP);
1191 	}
1192 
1193 	if (sp->se_window) {
1194 		start_window_system(sp);
1195 		sleep(WINDOW_WAIT);
1196 	}
1197 
1198 	sigemptyset(&mask);
1199 	sigprocmask(SIG_SETMASK, &mask, (sigset_t *) 0);
1200 
1201 #ifdef LOGIN_CAP
1202 	setprocresources(RESOURCE_GETTY);
1203 #endif
1204 	if (sp->se_type) {
1205 		/* Don't use malloc after fork */
1206 		strcpy(term, "TERM=");
1207 		strncat(term, sp->se_type, sizeof(term) - 6);
1208 		env[0] = term;
1209 		env[1] = 0;
1210 	}
1211 	else
1212 		env[0] = 0;
1213 	execve(sp->se_getty_argv[0], sp->se_getty_argv, env);
1214 	stall("can't exec getty '%s' for port %s: %m",
1215 		sp->se_getty_argv[0], sp->se_device);
1216 	_exit(1);
1217 }
1218 
1219 /*
1220  * Collect exit status for a child.
1221  * If an exiting login, start a new login running.
1222  */
1223 void
1224 #ifdef __STDC__
1225 collect_child(pid_t pid)
1226 #else
1227 collect_child(pid)
1228 	pid_t pid;
1229 #endif
1230 {
1231 	register session_t *sp, *sprev, *snext;
1232 
1233 	if (! sessions)
1234 		return;
1235 
1236 	if (! (sp = find_session(pid)))
1237 		return;
1238 
1239 	clear_session_logs(sp);
1240 	del_session(sp);
1241 	sp->se_process = 0;
1242 
1243 	if (sp->se_flags & SE_SHUTDOWN) {
1244 		if ((sprev = sp->se_prev) != NULL)
1245 			sprev->se_next = sp->se_next;
1246 		else
1247 			sessions = sp->se_next;
1248 		if ((snext = sp->se_next) != NULL)
1249 			snext->se_prev = sp->se_prev;
1250 		free_session(sp);
1251 		return;
1252 	}
1253 
1254 	if ((pid = start_getty(sp)) == -1) {
1255 		/* serious trouble */
1256 		requested_transition = clean_ttys;
1257 		return;
1258 	}
1259 
1260 	sp->se_process = pid;
1261 	sp->se_started = time((time_t *) 0);
1262 	add_session(sp);
1263 }
1264 
1265 /*
1266  * Catch a signal and request a state transition.
1267  */
1268 void
1269 transition_handler(sig)
1270 	int sig;
1271 {
1272 
1273 	switch (sig) {
1274 	case SIGHUP:
1275 		requested_transition = clean_ttys;
1276 		break;
1277 	case SIGUSR2:
1278 		howto = RB_POWEROFF;
1279 	case SIGUSR1:
1280 		howto |= RB_HALT;
1281 	case SIGINT:
1282 		Reboot = TRUE;
1283 	case SIGTERM:
1284 		requested_transition = death;
1285 		break;
1286 	case SIGTSTP:
1287 		requested_transition = catatonia;
1288 		break;
1289 	default:
1290 		requested_transition = 0;
1291 		break;
1292 	}
1293 }
1294 
1295 /*
1296  * Take the system multiuser.
1297  */
1298 state_func_t
1299 multi_user()
1300 {
1301 	pid_t pid;
1302 	register session_t *sp;
1303 
1304 	requested_transition = 0;
1305 
1306 	/*
1307 	 * If the administrator has not set the security level to -1
1308 	 * to indicate that the kernel should not run multiuser in secure
1309 	 * mode, and the run script has not set a higher level of security
1310 	 * than level 1, then put the kernel into secure mode.
1311 	 */
1312 	if (getsecuritylevel() == 0)
1313 		setsecuritylevel(1);
1314 
1315 	for (sp = sessions; sp; sp = sp->se_next) {
1316 		if (sp->se_process)
1317 			continue;
1318 		if ((pid = start_getty(sp)) == -1) {
1319 			/* serious trouble */
1320 			requested_transition = clean_ttys;
1321 			break;
1322 		}
1323 		sp->se_process = pid;
1324 		sp->se_started = time((time_t *) 0);
1325 		add_session(sp);
1326 	}
1327 
1328 	while (!requested_transition)
1329 		if ((pid = waitpid(-1, (int *) 0, 0)) != -1)
1330 			collect_child(pid);
1331 
1332 	return (state_func_t) requested_transition;
1333 }
1334 
1335 /*
1336  * This is an (n*2)+(n^2) algorithm.  We hope it isn't run often...
1337  */
1338 state_func_t
1339 clean_ttys()
1340 {
1341 	register session_t *sp, *sprev;
1342 	register struct ttyent *typ;
1343 	register int session_index = 0;
1344 	register int devlen;
1345 	char *old_getty, *old_window, *old_type;
1346 
1347 	if (! sessions)
1348 		return (state_func_t) multi_user;
1349 
1350 	/*
1351 	 * mark all sessions for death, (!SE_PRESENT)
1352 	 * as we find or create new ones they'll be marked as keepers,
1353 	 * we'll later nuke all the ones not found in /etc/ttys
1354 	 */
1355 	for (sp = sessions; sp != NULL; sp = sp->se_next)
1356 		sp->se_flags &= ~SE_PRESENT;
1357 
1358 	devlen = sizeof(_PATH_DEV) - 1;
1359 	while ((typ = getttyent()) != NULL) {
1360 		++session_index;
1361 
1362 		for (sprev = 0, sp = sessions; sp; sprev = sp, sp = sp->se_next)
1363 			if (strcmp(typ->ty_name, sp->se_device + devlen) == 0)
1364 				break;
1365 
1366 		if (sp) {
1367 			/* we want this one to live */
1368 			sp->se_flags |= SE_PRESENT;
1369 			if (sp->se_index != session_index) {
1370 				warning("port %s changed utmp index from %d to %d",
1371 				       sp->se_device, sp->se_index,
1372 				       session_index);
1373 				sp->se_index = session_index;
1374 			}
1375 			if ((typ->ty_status & TTY_ON) == 0 ||
1376 			    typ->ty_getty == 0) {
1377 				sp->se_flags |= SE_SHUTDOWN;
1378 				kill(sp->se_process, SIGHUP);
1379 				continue;
1380 			}
1381 			sp->se_flags &= ~SE_SHUTDOWN;
1382 			old_getty = sp->se_getty ? strdup(sp->se_getty) : 0;
1383 			old_window = sp->se_window ? strdup(sp->se_window) : 0;
1384 			old_type = sp->se_type ? strdup(sp->se_type) : 0;
1385 			if (setupargv(sp, typ) == 0) {
1386 				warning("can't parse getty for port %s",
1387 					sp->se_device);
1388 				sp->se_flags |= SE_SHUTDOWN;
1389 				kill(sp->se_process, SIGHUP);
1390 			}
1391 			else if (   !old_getty
1392 				 || (!old_type && sp->se_type)
1393 				 || (old_type && !sp->se_type)
1394 				 || (!old_window && sp->se_window)
1395 				 || (old_window && !sp->se_window)
1396 				 || (strcmp(old_getty, sp->se_getty) != 0)
1397 				 || (old_window && strcmp(old_window, sp->se_window) != 0)
1398 				 || (old_type && strcmp(old_type, sp->se_type) != 0)
1399 				) {
1400 				/* Don't set SE_SHUTDOWN here */
1401 				sp->se_nspace = 0;
1402 				sp->se_started = 0;
1403 				kill(sp->se_process, SIGHUP);
1404 			}
1405 			if (old_getty)
1406 				free(old_getty);
1407 			if (old_getty)
1408 				free(old_window);
1409 			if (old_type)
1410 				free(old_type);
1411 			continue;
1412 		}
1413 
1414 		new_session(sprev, session_index, typ);
1415 	}
1416 
1417 	endttyent();
1418 
1419 	/*
1420 	 * sweep through and kill all deleted sessions
1421 	 * ones who's /etc/ttys line was deleted (SE_PRESENT unset)
1422 	 */
1423 	for (sp = sessions; sp != NULL; sp = sp->se_next) {
1424 		if ((sp->se_flags & SE_PRESENT) == 0) {
1425 			sp->se_flags |= SE_SHUTDOWN;
1426 			kill(sp->se_process, SIGHUP);
1427 		}
1428 	}
1429 
1430 	return (state_func_t) multi_user;
1431 }
1432 
1433 /*
1434  * Block further logins.
1435  */
1436 state_func_t
1437 catatonia()
1438 {
1439 	register session_t *sp;
1440 
1441 	for (sp = sessions; sp; sp = sp->se_next)
1442 		sp->se_flags |= SE_SHUTDOWN;
1443 
1444 	return (state_func_t) multi_user;
1445 }
1446 
1447 /*
1448  * Note SIGALRM.
1449  */
1450 void
1451 alrm_handler(sig)
1452 	int sig;
1453 {
1454 	(void)sig;
1455 	clang = 1;
1456 }
1457 
1458 /*
1459  * Bring the system down to single user.
1460  */
1461 state_func_t
1462 death()
1463 {
1464 	register session_t *sp;
1465 	register int i;
1466 	pid_t pid;
1467 	static const int death_sigs[2] = { SIGTERM, SIGKILL };
1468 
1469 	/* NB: should send a message to the session logger to avoid blocking. */
1470 	logwtmp("~", "shutdown", "");
1471 
1472 	for (sp = sessions; sp; sp = sp->se_next) {
1473 		sp->se_flags |= SE_SHUTDOWN;
1474 		kill(sp->se_process, SIGHUP);
1475 	}
1476 
1477 	/* Try to run the rc.shutdown script within a period of time */
1478 	(void) runshutdown();
1479 
1480 	for (i = 0; i < 2; ++i) {
1481 		if (kill(-1, death_sigs[i]) == -1 && errno == ESRCH)
1482 			return (state_func_t) single_user;
1483 
1484 		clang = 0;
1485 		alarm(DEATH_WATCH);
1486 		do
1487 			if ((pid = waitpid(-1, (int *)0, 0)) != -1)
1488 				collect_child(pid);
1489 		while (clang == 0 && errno != ECHILD);
1490 
1491 		if (errno == ECHILD)
1492 			return (state_func_t) single_user;
1493 	}
1494 
1495 	warning("some processes would not die; ps axl advised");
1496 
1497 	return (state_func_t) single_user;
1498 }
1499 
1500 /*
1501  * Run the system shutdown script.
1502  *
1503  * Exit codes:      XXX I should document more
1504  * -2       shutdown script terminated abnormally
1505  * -1       fatal error - can't run script
1506  * 0        good.
1507  * >0       some error (exit code)
1508  */
1509 int
1510 runshutdown()
1511 {
1512 	pid_t pid, wpid;
1513 	int status;
1514 	int shutdowntimeout;
1515 	size_t len;
1516 	char *argv[4];
1517 	struct sigaction sa;
1518 	struct stat sb;
1519 
1520 	/*
1521 	 * rc.shutdown is optional, so to prevent any unnecessary
1522 	 * complaints from the shell we simply don't run it if the
1523 	 * file does not exist. If the stat() here fails for other
1524 	 * reasons, we'll let the shell complain.
1525 	 */
1526 	if (stat(_PATH_RUNDOWN, &sb) == -1 && errno == ENOENT)
1527 		return 0;
1528 
1529 	if ((pid = fork()) == 0) {
1530 		int	fd;
1531 
1532 		/* Assume that init already grab console as ctty before */
1533 
1534 		sigemptyset(&sa.sa_mask);
1535 		sa.sa_flags = 0;
1536 		sa.sa_handler = SIG_IGN;
1537 		(void) sigaction(SIGTSTP, &sa, (struct sigaction *)0);
1538 		(void) sigaction(SIGHUP, &sa, (struct sigaction *)0);
1539 
1540 		if ((fd = open(_PATH_CONSOLE, O_RDWR)) == -1)
1541 		    warning("can't open %s: %m", _PATH_CONSOLE);
1542 		else {
1543 		    (void) dup2(fd, 0);
1544 		    (void) dup2(fd, 1);
1545 		    (void) dup2(fd, 2);
1546 		    if (fd > 2)
1547 			close(fd);
1548 		}
1549 
1550 		/*
1551 		 * Run the shutdown script.
1552 		 */
1553 		argv[0] = "sh";
1554 		argv[1] = _PATH_RUNDOWN;
1555 		if (Reboot)
1556 			argv[2] = "reboot";
1557 		else
1558 			argv[2] = "single";
1559 		argv[3] = 0;
1560 
1561 		sigprocmask(SIG_SETMASK, &sa.sa_mask, (sigset_t *) 0);
1562 
1563 #ifdef LOGIN_CAP
1564 		setprocresources(RESOURCE_RC);
1565 #endif
1566 		execv(_PATH_BSHELL, argv);
1567 		warning("can't exec %s for %s: %m", _PATH_BSHELL, _PATH_RUNDOWN);
1568 		_exit(1);	/* force single user mode */
1569 	}
1570 
1571 	if (pid == -1) {
1572 		emergency("can't fork for %s on %s: %m",
1573 			_PATH_BSHELL, _PATH_RUNDOWN);
1574 		while (waitpid(-1, (int *) 0, WNOHANG) > 0)
1575 			continue;
1576 		sleep(STALL_TIMEOUT);
1577 		return -1;
1578 	}
1579 
1580 	len = sizeof(shutdowntimeout);
1581 	if (sysctlbyname("kern.shutdown_timeout",
1582 			 &shutdowntimeout,
1583 			 &len, NULL, 0) == -1 || shutdowntimeout < 2)
1584 	    shutdowntimeout = DEATH_SCRIPT;
1585 	alarm(shutdowntimeout);
1586 	clang = 0;
1587 	/*
1588 	 * Copied from single_user().  This is a bit paranoid.
1589 	 * Use the same ALRM handler.
1590 	 */
1591 	do {
1592 		if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1)
1593 			collect_child(wpid);
1594 		if (clang == 1) {
1595 			/* we were waiting for the sub-shell */
1596 			kill(wpid, SIGTERM);
1597 			warning("timeout expired for %s on %s: %m; going to single used mode",
1598 				_PATH_BSHELL, _PATH_RUNDOWN);
1599 			return -1;
1600 		}
1601 		if (wpid == -1) {
1602 			if (errno == EINTR)
1603 				continue;
1604 			warning("wait for %s on %s failed: %m; going to single user mode",
1605 				_PATH_BSHELL, _PATH_RUNDOWN);
1606 			return -1;
1607 		}
1608 		if (wpid == pid && WIFSTOPPED(status)) {
1609 			warning("init: %s on %s stopped, restarting\n",
1610 				_PATH_BSHELL, _PATH_RUNDOWN);
1611 			kill(pid, SIGCONT);
1612 			wpid = -1;
1613 		}
1614 	} while (wpid != pid && !clang);
1615 
1616 	/* Turn off the alarm */
1617 	alarm(0);
1618 
1619 	if (WIFSIGNALED(status) && WTERMSIG(status) == SIGTERM &&
1620 	    requested_transition == catatonia) {
1621 		/*
1622 		 * /etc/rc.shutdown executed /sbin/reboot;
1623 		 * wait for the end quietly
1624 		 */
1625 		sigset_t s;
1626 
1627 		sigfillset(&s);
1628 		for (;;)
1629 			sigsuspend(&s);
1630 	}
1631 
1632 	if (!WIFEXITED(status)) {
1633 		warning("%s on %s terminated abnormally, going to single user mode",
1634 			_PATH_BSHELL, _PATH_RUNDOWN);
1635 		return -2;
1636 	}
1637 
1638 	if ((status = WEXITSTATUS(status)) != 0)
1639 		warning("%s returned status %d", _PATH_RUNDOWN, status);
1640 
1641 	return status;
1642 }
1643 
1644 char *
1645 strk (char *p)
1646 {
1647     static char *t;
1648     char *q;
1649     int c;
1650 
1651     if (p)
1652 	t = p;
1653     if (!t)
1654 	return 0;
1655 
1656     c = *t;
1657     while (c == ' ' || c == '\t' )
1658 	c = *++t;
1659     if (!c) {
1660 	t = 0;
1661 	return 0;
1662     }
1663     q = t;
1664     if (c == '\'') {
1665 	c = *++t;
1666 	q = t;
1667 	while (c && c != '\'')
1668 	    c = *++t;
1669 	if (!c)  /* unterminated string */
1670 	    q = t = 0;
1671 	else
1672 	    *t++ = 0;
1673     } else {
1674 	while (c && c != ' ' && c != '\t' )
1675 	    c = *++t;
1676 	*t++ = 0;
1677 	if (!c)
1678 	    t = 0;
1679     }
1680     return q;
1681 }
1682 
1683 #ifdef LOGIN_CAP
1684 void
1685 setprocresources(cname)
1686 	const char *cname;
1687 {
1688 	login_cap_t *lc;
1689 	if ((lc = login_getclassbyname(cname, NULL)) != NULL) {
1690 		setusercontext(lc, (struct passwd*)NULL, 0, LOGIN_SETPRIORITY|LOGIN_SETRESOURCES);
1691 		login_close(lc);
1692 	}
1693 }
1694 #endif
1695