xref: /freebsd/sbin/init/init.c (revision 23f282aa31e9b6fceacd449020e936e98d6f2298)
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 
514 	name[0] = CTL_KERN;
515 	name[1] = KERN_SECURELVL;
516 	len = sizeof curlevel;
517 	if (sysctl(name, 2, &curlevel, &len, NULL, 0) == -1) {
518 		emergency("cannot get kernel security level: %s",
519 		    strerror(errno));
520 		return (-1);
521 	}
522 	return (curlevel);
523 #else
524 	return (-1);
525 #endif
526 }
527 
528 /*
529  * Set the security level of the kernel.
530  */
531 void
532 setsecuritylevel(newlevel)
533 	int newlevel;
534 {
535 #ifdef KERN_SECURELVL
536 	int name[2], curlevel;
537 
538 	curlevel = getsecuritylevel();
539 	if (newlevel == curlevel)
540 		return;
541 	name[0] = CTL_KERN;
542 	name[1] = KERN_SECURELVL;
543 	if (sysctl(name, 2, NULL, NULL, &newlevel, sizeof newlevel) == -1) {
544 		emergency(
545 		    "cannot change kernel security level from %d to %d: %s",
546 		    curlevel, newlevel, strerror(errno));
547 		return;
548 	}
549 #ifdef SECURE
550 	warning("kernel security level changed from %d to %d",
551 	    curlevel, newlevel);
552 #endif
553 #endif
554 }
555 
556 /*
557  * Change states in the finite state machine.
558  * The initial state is passed as an argument.
559  */
560 void
561 transition(s)
562 	state_t s;
563 {
564 	for (;;)
565 		s = (state_t) (*s)();
566 }
567 
568 /*
569  * Close out the accounting files for a login session.
570  * NB: should send a message to the session logger to avoid blocking.
571  */
572 void
573 clear_session_logs(sp)
574 	session_t *sp;
575 {
576 	char *line = sp->se_device + sizeof(_PATH_DEV) - 1;
577 
578 	if (logout(line))
579 		logwtmp(line, "", "");
580 }
581 
582 /*
583  * Start a session and allocate a controlling terminal.
584  * Only called by children of init after forking.
585  */
586 void
587 setctty(name)
588 	char *name;
589 {
590 	int fd;
591 
592 	(void) revoke(name);
593 	if ((fd = open(name, O_RDWR)) == -1) {
594 		stall("can't open %s: %m", name);
595 		_exit(1);
596 	}
597 	if (login_tty(fd) == -1) {
598 		stall("can't get %s for controlling terminal: %m", name);
599 		_exit(1);
600 	}
601 }
602 
603 /*
604  * Bring the system up single user.
605  */
606 state_func_t
607 single_user()
608 {
609 	pid_t pid, wpid;
610 	int status;
611 	sigset_t mask;
612 	char *shell = _PATH_BSHELL;
613 	char *argv[2];
614 #ifdef SECURE
615 	struct ttyent *typ;
616 	struct passwd *pp;
617 	static const char banner[] =
618 		"Enter root password, or ^D to go multi-user\n";
619 	char *clear, *password;
620 #endif
621 #ifdef DEBUGSHELL
622 	char altshell[128];
623 #endif
624 
625 	if (Reboot) {
626 		/* Instead of going single user, let's reboot the machine */
627 		sync();
628 		alarm(2);
629 		pause();
630 		reboot(howto);
631 		_exit(0);
632 	}
633 
634 	if ((pid = fork()) == 0) {
635 		/*
636 		 * Start the single user session.
637 		 */
638 		setctty(_PATH_CONSOLE);
639 
640 #ifdef SECURE
641 		/*
642 		 * Check the root password.
643 		 * We don't care if the console is 'on' by default;
644 		 * it's the only tty that can be 'off' and 'secure'.
645 		 */
646 		typ = getttynam("console");
647 		pp = getpwnam("root");
648 		if (typ && (typ->ty_status & TTY_SECURE) == 0 &&
649 		    pp && *pp->pw_passwd) {
650 			write(2, banner, sizeof banner - 1);
651 			for (;;) {
652 				clear = getpass("Password:");
653 				if (clear == 0 || *clear == '\0')
654 					_exit(0);
655 				password = crypt(clear, pp->pw_passwd);
656 				bzero(clear, _PASSWORD_LEN);
657 				if (strcmp(password, pp->pw_passwd) == 0)
658 					break;
659 				warning("single-user login failed\n");
660 			}
661 		}
662 		endttyent();
663 		endpwent();
664 #endif /* SECURE */
665 
666 #ifdef DEBUGSHELL
667 		{
668 			char *cp = altshell;
669 			int num;
670 
671 #define	SHREQUEST \
672 	"Enter full pathname of shell or RETURN for " _PATH_BSHELL ": "
673 			(void)write(STDERR_FILENO,
674 			    SHREQUEST, sizeof(SHREQUEST) - 1);
675 			while ((num = read(STDIN_FILENO, cp, 1)) != -1 &&
676 			    num != 0 && *cp != '\n' && cp < &altshell[127])
677 					cp++;
678 			*cp = '\0';
679 			if (altshell[0] != '\0')
680 				shell = altshell;
681 		}
682 #endif /* DEBUGSHELL */
683 
684 		/*
685 		 * Unblock signals.
686 		 * We catch all the interesting ones,
687 		 * and those are reset to SIG_DFL on exec.
688 		 */
689 		sigemptyset(&mask);
690 		sigprocmask(SIG_SETMASK, &mask, (sigset_t *) 0);
691 
692 		/*
693 		 * Fire off a shell.
694 		 * If the default one doesn't work, try the Bourne shell.
695 		 */
696 		argv[0] = "-sh";
697 		argv[1] = 0;
698 		execv(shell, argv);
699 		emergency("can't exec %s for single user: %m", shell);
700 		execv(_PATH_BSHELL, argv);
701 		emergency("can't exec %s for single user: %m", _PATH_BSHELL);
702 		sleep(STALL_TIMEOUT);
703 		_exit(1);
704 	}
705 
706 	if (pid == -1) {
707 		/*
708 		 * We are seriously hosed.  Do our best.
709 		 */
710 		emergency("can't fork single-user shell, trying again");
711 		while (waitpid(-1, (int *) 0, WNOHANG) > 0)
712 			continue;
713 		return (state_func_t) single_user;
714 	}
715 
716 	requested_transition = 0;
717 	do {
718 		if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1)
719 			collect_child(wpid);
720 		if (wpid == -1) {
721 			if (errno == EINTR)
722 				continue;
723 			warning("wait for single-user shell failed: %m; restarting");
724 			return (state_func_t) single_user;
725 		}
726 		if (wpid == pid && WIFSTOPPED(status)) {
727 			warning("init: shell stopped, restarting\n");
728 			kill(pid, SIGCONT);
729 			wpid = -1;
730 		}
731 	} while (wpid != pid && !requested_transition);
732 
733 	if (requested_transition)
734 		return (state_func_t) requested_transition;
735 
736 	if (!WIFEXITED(status)) {
737 		if (WTERMSIG(status) == SIGKILL) {
738 			/*
739 			 *  reboot(8) killed shell?
740 			 */
741 			warning("single user shell terminated.");
742 			sleep(STALL_TIMEOUT);
743 			_exit(0);
744 		} else {
745 			warning("single user shell terminated, restarting");
746 			return (state_func_t) single_user;
747 		}
748 	}
749 
750 	runcom_mode = FASTBOOT;
751 	return (state_func_t) runcom;
752 }
753 
754 /*
755  * Run the system startup script.
756  */
757 state_func_t
758 runcom()
759 {
760 	pid_t pid, wpid;
761 	int status;
762 	char *argv[4];
763 	struct sigaction sa;
764 
765 	if ((pid = fork()) == 0) {
766 		sigemptyset(&sa.sa_mask);
767 		sa.sa_flags = 0;
768 		sa.sa_handler = SIG_IGN;
769 		(void) sigaction(SIGTSTP, &sa, (struct sigaction *)0);
770 		(void) sigaction(SIGHUP, &sa, (struct sigaction *)0);
771 
772 		setctty(_PATH_CONSOLE);
773 
774 		argv[0] = "sh";
775 		argv[1] = _PATH_RUNCOM;
776 		argv[2] = runcom_mode == AUTOBOOT ? "autoboot" : 0;
777 		argv[3] = 0;
778 
779 		sigprocmask(SIG_SETMASK, &sa.sa_mask, (sigset_t *) 0);
780 
781 #ifdef LOGIN_CAP
782 		setprocresources(RESOURCE_RC);
783 #endif
784 		execv(_PATH_BSHELL, argv);
785 		stall("can't exec %s for %s: %m", _PATH_BSHELL, _PATH_RUNCOM);
786 		_exit(1);	/* force single user mode */
787 	}
788 
789 	if (pid == -1) {
790 		emergency("can't fork for %s on %s: %m",
791 			_PATH_BSHELL, _PATH_RUNCOM);
792 		while (waitpid(-1, (int *) 0, WNOHANG) > 0)
793 			continue;
794 		sleep(STALL_TIMEOUT);
795 		return (state_func_t) single_user;
796 	}
797 
798 	/*
799 	 * Copied from single_user().  This is a bit paranoid.
800 	 */
801 	do {
802 		if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1)
803 			collect_child(wpid);
804 		if (wpid == -1) {
805 			if (errno == EINTR)
806 				continue;
807 			warning("wait for %s on %s failed: %m; going to single user mode",
808 				_PATH_BSHELL, _PATH_RUNCOM);
809 			return (state_func_t) single_user;
810 		}
811 		if (wpid == pid && WIFSTOPPED(status)) {
812 			warning("init: %s on %s stopped, restarting\n",
813 				_PATH_BSHELL, _PATH_RUNCOM);
814 			kill(pid, SIGCONT);
815 			wpid = -1;
816 		}
817 	} while (wpid != pid);
818 
819 	if (WIFSIGNALED(status) && WTERMSIG(status) == SIGTERM &&
820 	    requested_transition == catatonia) {
821 		/* /etc/rc executed /sbin/reboot; wait for the end quietly */
822 		sigset_t s;
823 
824 		sigfillset(&s);
825 		for (;;)
826 			sigsuspend(&s);
827 	}
828 
829 	if (!WIFEXITED(status)) {
830 		warning("%s on %s terminated abnormally, going to single user mode",
831 			_PATH_BSHELL, _PATH_RUNCOM);
832 		return (state_func_t) single_user;
833 	}
834 
835 	if (WEXITSTATUS(status))
836 		return (state_func_t) single_user;
837 
838 	runcom_mode = AUTOBOOT;		/* the default */
839 	/* NB: should send a message to the session logger to avoid blocking. */
840 	logwtmp("~", "reboot", "");
841 	return (state_func_t) read_ttys;
842 }
843 
844 /*
845  * Open the session database.
846  *
847  * NB: We could pass in the size here; is it necessary?
848  */
849 int
850 start_session_db()
851 {
852 	if (session_db && (*session_db->close)(session_db))
853 		emergency("session database close: %s", strerror(errno));
854 	if ((session_db = dbopen(NULL, O_RDWR, 0, DB_HASH, NULL)) == 0) {
855 		emergency("session database open: %s", strerror(errno));
856 		return (1);
857 	}
858 	return (0);
859 
860 }
861 
862 /*
863  * Add a new login session.
864  */
865 void
866 add_session(sp)
867 	session_t *sp;
868 {
869 	DBT key;
870 	DBT data;
871 
872 	key.data = &sp->se_process;
873 	key.size = sizeof sp->se_process;
874 	data.data = &sp;
875 	data.size = sizeof sp;
876 
877 	if ((*session_db->put)(session_db, &key, &data, 0))
878 		emergency("insert %d: %s", sp->se_process, strerror(errno));
879 }
880 
881 /*
882  * Delete an old login session.
883  */
884 void
885 del_session(sp)
886 	session_t *sp;
887 {
888 	DBT key;
889 
890 	key.data = &sp->se_process;
891 	key.size = sizeof sp->se_process;
892 
893 	if ((*session_db->del)(session_db, &key, 0))
894 		emergency("delete %d: %s", sp->se_process, strerror(errno));
895 }
896 
897 /*
898  * Look up a login session by pid.
899  */
900 session_t *
901 #ifdef __STDC__
902 find_session(pid_t pid)
903 #else
904 find_session(pid)
905 	pid_t pid;
906 #endif
907 {
908 	DBT key;
909 	DBT data;
910 	session_t *ret;
911 
912 	key.data = &pid;
913 	key.size = sizeof pid;
914 	if ((*session_db->get)(session_db, &key, &data, 0) != 0)
915 		return 0;
916 	bcopy(data.data, (char *)&ret, sizeof(ret));
917 	return ret;
918 }
919 
920 /*
921  * Construct an argument vector from a command line.
922  */
923 char **
924 construct_argv(command)
925 	char *command;
926 {
927 	char *strk (char *);
928 	register int argc = 0;
929 	register char **argv = (char **) malloc(((strlen(command) + 1) / 2 + 1)
930 						* sizeof (char *));
931 
932 	if ((argv[argc++] = strk(command)) == 0) {
933 		free(argv);
934 		return (NULL);
935 	}
936 	while ((argv[argc++] = strk((char *) 0)) != NULL)
937 		continue;
938 	return argv;
939 }
940 
941 /*
942  * Deallocate a session descriptor.
943  */
944 void
945 free_session(sp)
946 	register session_t *sp;
947 {
948 	free(sp->se_device);
949 	if (sp->se_getty) {
950 		free(sp->se_getty);
951 		free(sp->se_getty_argv_space);
952 		free(sp->se_getty_argv);
953 	}
954 	if (sp->se_window) {
955 		free(sp->se_window);
956 		free(sp->se_window_argv_space);
957 		free(sp->se_window_argv);
958 	}
959 	if (sp->se_type)
960 		free(sp->se_type);
961 	free(sp);
962 }
963 
964 /*
965  * Allocate a new session descriptor.
966  * Mark it SE_PRESENT.
967  */
968 session_t *
969 new_session(sprev, session_index, typ)
970 	session_t *sprev;
971 	int session_index;
972 	register struct ttyent *typ;
973 {
974 	register session_t *sp;
975 	int fd;
976 
977 	if ((typ->ty_status & TTY_ON) == 0 ||
978 	    typ->ty_name == 0 ||
979 	    typ->ty_getty == 0)
980 		return 0;
981 
982 	sp = (session_t *) calloc(1, sizeof (session_t));
983 
984 	sp->se_index = session_index;
985 	sp->se_flags |= SE_PRESENT;
986 
987 	sp->se_device = malloc(sizeof(_PATH_DEV) + strlen(typ->ty_name));
988 	(void) sprintf(sp->se_device, "%s%s", _PATH_DEV, typ->ty_name);
989 
990 	/*
991 	 * Attempt to open the device, if we get "device not configured"
992 	 * then don't add the device to the session list.
993 	 */
994 	if ((fd = open(sp->se_device, O_RDONLY | O_NONBLOCK, 0)) < 0) {
995 		if (errno == ENXIO) {
996 			free_session(sp);
997 			return (0);
998 		}
999 	} else
1000 		close(fd);
1001 
1002 	if (setupargv(sp, typ) == 0) {
1003 		free_session(sp);
1004 		return (0);
1005 	}
1006 
1007 	sp->se_next = 0;
1008 	if (sprev == 0) {
1009 		sessions = sp;
1010 		sp->se_prev = 0;
1011 	} else {
1012 		sprev->se_next = sp;
1013 		sp->se_prev = sprev;
1014 	}
1015 
1016 	return sp;
1017 }
1018 
1019 /*
1020  * Calculate getty and if useful window argv vectors.
1021  */
1022 int
1023 setupargv(sp, typ)
1024 	session_t *sp;
1025 	struct ttyent *typ;
1026 {
1027 
1028 	if (sp->se_getty) {
1029 		free(sp->se_getty);
1030 		free(sp->se_getty_argv_space);
1031 		free(sp->se_getty_argv);
1032 	}
1033 	sp->se_getty = malloc(strlen(typ->ty_getty) + strlen(typ->ty_name) + 2);
1034 	(void) sprintf(sp->se_getty, "%s %s", typ->ty_getty, typ->ty_name);
1035 	sp->se_getty_argv_space = strdup(sp->se_getty);
1036 	sp->se_getty_argv = construct_argv(sp->se_getty_argv_space);
1037 	if (sp->se_getty_argv == 0) {
1038 		warning("can't parse getty for port %s", sp->se_device);
1039 		free(sp->se_getty);
1040 		free(sp->se_getty_argv_space);
1041 		sp->se_getty = sp->se_getty_argv_space = 0;
1042 		return (0);
1043 	}
1044 	if (sp->se_window) {
1045 		free(sp->se_window);
1046 		free(sp->se_window_argv_space);
1047 		free(sp->se_window_argv);
1048 	}
1049 	sp->se_window = sp->se_window_argv_space = 0;
1050 	sp->se_window_argv = 0;
1051 	if (typ->ty_window) {
1052 		sp->se_window = strdup(typ->ty_window);
1053 		sp->se_window_argv_space = strdup(sp->se_window);
1054 		sp->se_window_argv = construct_argv(sp->se_window_argv_space);
1055 		if (sp->se_window_argv == 0) {
1056 			warning("can't parse window for port %s",
1057 				sp->se_device);
1058 			free(sp->se_window_argv_space);
1059 			free(sp->se_window);
1060 			sp->se_window = sp->se_window_argv_space = 0;
1061 			return (0);
1062 		}
1063 	}
1064 	if (sp->se_type)
1065 		free(sp->se_type);
1066 	sp->se_type = typ->ty_type ? strdup(typ->ty_type) : 0;
1067 	return (1);
1068 }
1069 
1070 /*
1071  * Walk the list of ttys and create sessions for each active line.
1072  */
1073 state_func_t
1074 read_ttys()
1075 {
1076 	int session_index = 0;
1077 	register session_t *sp, *snext;
1078 	register struct ttyent *typ;
1079 
1080 	/*
1081 	 * Destroy any previous session state.
1082 	 * There shouldn't be any, but just in case...
1083 	 */
1084 	for (sp = sessions; sp; sp = snext) {
1085 		if (sp->se_process)
1086 			clear_session_logs(sp);
1087 		snext = sp->se_next;
1088 		free_session(sp);
1089 	}
1090 	sessions = 0;
1091 	if (start_session_db())
1092 		return (state_func_t) single_user;
1093 
1094 	/*
1095 	 * Allocate a session entry for each active port.
1096 	 * Note that sp starts at 0.
1097 	 */
1098 	while ((typ = getttyent()) != NULL)
1099 		if ((snext = new_session(sp, ++session_index, typ)) != NULL)
1100 			sp = snext;
1101 
1102 	endttyent();
1103 
1104 	return (state_func_t) multi_user;
1105 }
1106 
1107 /*
1108  * Start a window system running.
1109  */
1110 void
1111 start_window_system(sp)
1112 	session_t *sp;
1113 {
1114 	pid_t pid;
1115 	sigset_t mask;
1116 	char term[64], *env[2];
1117 
1118 	if ((pid = fork()) == -1) {
1119 		emergency("can't fork for window system on port %s: %m",
1120 			sp->se_device);
1121 		/* hope that getty fails and we can try again */
1122 		return;
1123 	}
1124 
1125 	if (pid)
1126 		return;
1127 
1128 	sigemptyset(&mask);
1129 	sigprocmask(SIG_SETMASK, &mask, (sigset_t *) 0);
1130 
1131 	if (setsid() < 0)
1132 		emergency("setsid failed (window) %m");
1133 
1134 #ifdef LOGIN_CAP
1135 	setprocresources(RESOURCE_WINDOW);
1136 #endif
1137 	if (sp->se_type) {
1138 		/* Don't use malloc after fork */
1139 		strcpy(term, "TERM=");
1140 		strncat(term, sp->se_type, sizeof(term) - 6);
1141 		env[0] = term;
1142 		env[1] = 0;
1143 	}
1144 	else
1145 		env[0] = 0;
1146 	execve(sp->se_window_argv[0], sp->se_window_argv, env);
1147 	stall("can't exec window system '%s' for port %s: %m",
1148 		sp->se_window_argv[0], sp->se_device);
1149 	_exit(1);
1150 }
1151 
1152 /*
1153  * Start a login session running.
1154  */
1155 pid_t
1156 start_getty(sp)
1157 	session_t *sp;
1158 {
1159 	pid_t pid;
1160 	sigset_t mask;
1161 	time_t current_time = time((time_t *) 0);
1162 	int too_quick = 0;
1163 	char term[64], *env[2];
1164 
1165 	if (current_time >= sp->se_started &&
1166 	    current_time - sp->se_started < GETTY_SPACING) {
1167 		if (++sp->se_nspace > GETTY_NSPACE) {
1168 			sp->se_nspace = 0;
1169 			too_quick = 1;
1170 		}
1171 	} else
1172 		sp->se_nspace = 0;
1173 
1174 	/*
1175 	 * fork(), not vfork() -- we can't afford to block.
1176 	 */
1177 	if ((pid = fork()) == -1) {
1178 		emergency("can't fork for getty on port %s: %m", sp->se_device);
1179 		return -1;
1180 	}
1181 
1182 	if (pid)
1183 		return pid;
1184 
1185 	if (too_quick) {
1186 		warning("getty repeating too quickly on port %s, sleeping %d secs",
1187 			sp->se_device, GETTY_SLEEP);
1188 		sleep((unsigned) GETTY_SLEEP);
1189 	}
1190 
1191 	if (sp->se_window) {
1192 		start_window_system(sp);
1193 		sleep(WINDOW_WAIT);
1194 	}
1195 
1196 	sigemptyset(&mask);
1197 	sigprocmask(SIG_SETMASK, &mask, (sigset_t *) 0);
1198 
1199 #ifdef LOGIN_CAP
1200 	setprocresources(RESOURCE_GETTY);
1201 #endif
1202 	if (sp->se_type) {
1203 		/* Don't use malloc after fork */
1204 		strcpy(term, "TERM=");
1205 		strncat(term, sp->se_type, sizeof(term) - 6);
1206 		env[0] = term;
1207 		env[1] = 0;
1208 	}
1209 	else
1210 		env[0] = 0;
1211 	execve(sp->se_getty_argv[0], sp->se_getty_argv, env);
1212 	stall("can't exec getty '%s' for port %s: %m",
1213 		sp->se_getty_argv[0], sp->se_device);
1214 	_exit(1);
1215 }
1216 
1217 /*
1218  * Collect exit status for a child.
1219  * If an exiting login, start a new login running.
1220  */
1221 void
1222 #ifdef __STDC__
1223 collect_child(pid_t pid)
1224 #else
1225 collect_child(pid)
1226 	pid_t pid;
1227 #endif
1228 {
1229 	register session_t *sp, *sprev, *snext;
1230 
1231 	if (! sessions)
1232 		return;
1233 
1234 	if (! (sp = find_session(pid)))
1235 		return;
1236 
1237 	clear_session_logs(sp);
1238 	del_session(sp);
1239 	sp->se_process = 0;
1240 
1241 	if (sp->se_flags & SE_SHUTDOWN) {
1242 		if ((sprev = sp->se_prev) != NULL)
1243 			sprev->se_next = sp->se_next;
1244 		else
1245 			sessions = sp->se_next;
1246 		if ((snext = sp->se_next) != NULL)
1247 			snext->se_prev = sp->se_prev;
1248 		free_session(sp);
1249 		return;
1250 	}
1251 
1252 	if ((pid = start_getty(sp)) == -1) {
1253 		/* serious trouble */
1254 		requested_transition = clean_ttys;
1255 		return;
1256 	}
1257 
1258 	sp->se_process = pid;
1259 	sp->se_started = time((time_t *) 0);
1260 	add_session(sp);
1261 }
1262 
1263 /*
1264  * Catch a signal and request a state transition.
1265  */
1266 void
1267 transition_handler(sig)
1268 	int sig;
1269 {
1270 
1271 	switch (sig) {
1272 	case SIGHUP:
1273 		requested_transition = clean_ttys;
1274 		break;
1275 	case SIGUSR2:
1276 		howto = RB_POWEROFF;
1277 	case SIGUSR1:
1278 		howto |= RB_HALT;
1279 	case SIGINT:
1280 		Reboot = TRUE;
1281 	case SIGTERM:
1282 		requested_transition = death;
1283 		break;
1284 	case SIGTSTP:
1285 		requested_transition = catatonia;
1286 		break;
1287 	default:
1288 		requested_transition = 0;
1289 		break;
1290 	}
1291 }
1292 
1293 /*
1294  * Take the system multiuser.
1295  */
1296 state_func_t
1297 multi_user()
1298 {
1299 	pid_t pid;
1300 	register session_t *sp;
1301 
1302 	requested_transition = 0;
1303 
1304 	/*
1305 	 * If the administrator has not set the security level to -1
1306 	 * to indicate that the kernel should not run multiuser in secure
1307 	 * mode, and the run script has not set a higher level of security
1308 	 * than level 1, then put the kernel into secure mode.
1309 	 */
1310 	if (getsecuritylevel() == 0)
1311 		setsecuritylevel(1);
1312 
1313 	for (sp = sessions; sp; sp = sp->se_next) {
1314 		if (sp->se_process)
1315 			continue;
1316 		if ((pid = start_getty(sp)) == -1) {
1317 			/* serious trouble */
1318 			requested_transition = clean_ttys;
1319 			break;
1320 		}
1321 		sp->se_process = pid;
1322 		sp->se_started = time((time_t *) 0);
1323 		add_session(sp);
1324 	}
1325 
1326 	while (!requested_transition)
1327 		if ((pid = waitpid(-1, (int *) 0, 0)) != -1)
1328 			collect_child(pid);
1329 
1330 	return (state_func_t) requested_transition;
1331 }
1332 
1333 /*
1334  * This is an (n*2)+(n^2) algorithm.  We hope it isn't run often...
1335  */
1336 state_func_t
1337 clean_ttys()
1338 {
1339 	register session_t *sp, *sprev;
1340 	register struct ttyent *typ;
1341 	register int session_index = 0;
1342 	register int devlen;
1343 	char *old_getty, *old_window, *old_type;
1344 
1345 	if (! sessions)
1346 		return (state_func_t) multi_user;
1347 
1348 	/*
1349 	 * mark all sessions for death, (!SE_PRESENT)
1350 	 * as we find or create new ones they'll be marked as keepers,
1351 	 * we'll later nuke all the ones not found in /etc/ttys
1352 	 */
1353 	for (sp = sessions; sp != NULL; sp = sp->se_next)
1354 		sp->se_flags &= ~SE_PRESENT;
1355 
1356 	devlen = sizeof(_PATH_DEV) - 1;
1357 	while ((typ = getttyent()) != NULL) {
1358 		++session_index;
1359 
1360 		for (sprev = 0, sp = sessions; sp; sprev = sp, sp = sp->se_next)
1361 			if (strcmp(typ->ty_name, sp->se_device + devlen) == 0)
1362 				break;
1363 
1364 		if (sp) {
1365 			/* we want this one to live */
1366 			sp->se_flags |= SE_PRESENT;
1367 			if (sp->se_index != session_index) {
1368 				warning("port %s changed utmp index from %d to %d",
1369 				       sp->se_device, sp->se_index,
1370 				       session_index);
1371 				sp->se_index = session_index;
1372 			}
1373 			if ((typ->ty_status & TTY_ON) == 0 ||
1374 			    typ->ty_getty == 0) {
1375 				sp->se_flags |= SE_SHUTDOWN;
1376 				kill(sp->se_process, SIGHUP);
1377 				continue;
1378 			}
1379 			sp->se_flags &= ~SE_SHUTDOWN;
1380 			old_getty = sp->se_getty ? strdup(sp->se_getty) : 0;
1381 			old_window = sp->se_window ? strdup(sp->se_window) : 0;
1382 			old_type = sp->se_type ? strdup(sp->se_type) : 0;
1383 			if (setupargv(sp, typ) == 0) {
1384 				warning("can't parse getty for port %s",
1385 					sp->se_device);
1386 				sp->se_flags |= SE_SHUTDOWN;
1387 				kill(sp->se_process, SIGHUP);
1388 			}
1389 			else if (   !old_getty
1390 				 || (!old_type && sp->se_type)
1391 				 || (old_type && !sp->se_type)
1392 				 || (!old_window && sp->se_window)
1393 				 || (old_window && !sp->se_window)
1394 				 || (strcmp(old_getty, sp->se_getty) != 0)
1395 				 || (old_window && strcmp(old_window, sp->se_window) != 0)
1396 				 || (old_type && strcmp(old_type, sp->se_type) != 0)
1397 				) {
1398 				/* Don't set SE_SHUTDOWN here */
1399 				sp->se_nspace = 0;
1400 				sp->se_started = 0;
1401 				kill(sp->se_process, SIGHUP);
1402 			}
1403 			if (old_getty)
1404 				free(old_getty);
1405 			if (old_getty)
1406 				free(old_window);
1407 			if (old_type)
1408 				free(old_type);
1409 			continue;
1410 		}
1411 
1412 		new_session(sprev, session_index, typ);
1413 	}
1414 
1415 	endttyent();
1416 
1417 	/*
1418 	 * sweep through and kill all deleted sessions
1419 	 * ones who's /etc/ttys line was deleted (SE_PRESENT unset)
1420 	 */
1421 	for (sp = sessions; sp != NULL; sp = sp->se_next) {
1422 		if ((sp->se_flags & SE_PRESENT) == 0) {
1423 			sp->se_flags |= SE_SHUTDOWN;
1424 			kill(sp->se_process, SIGHUP);
1425 		}
1426 	}
1427 
1428 	return (state_func_t) multi_user;
1429 }
1430 
1431 /*
1432  * Block further logins.
1433  */
1434 state_func_t
1435 catatonia()
1436 {
1437 	register session_t *sp;
1438 
1439 	for (sp = sessions; sp; sp = sp->se_next)
1440 		sp->se_flags |= SE_SHUTDOWN;
1441 
1442 	return (state_func_t) multi_user;
1443 }
1444 
1445 /*
1446  * Note SIGALRM.
1447  */
1448 void
1449 alrm_handler(sig)
1450 	int sig;
1451 {
1452 	(void)sig;
1453 	clang = 1;
1454 }
1455 
1456 /*
1457  * Bring the system down to single user.
1458  */
1459 state_func_t
1460 death()
1461 {
1462 	register session_t *sp;
1463 	register int i;
1464 	pid_t pid;
1465 	static const int death_sigs[2] = { SIGTERM, SIGKILL };
1466 
1467 	/* NB: should send a message to the session logger to avoid blocking. */
1468 	logwtmp("~", "shutdown", "");
1469 
1470 	for (sp = sessions; sp; sp = sp->se_next) {
1471 		sp->se_flags |= SE_SHUTDOWN;
1472 		kill(sp->se_process, SIGHUP);
1473 	}
1474 
1475 	/* Try to run the rc.shutdown script within a period of time */
1476 	(void) runshutdown();
1477 
1478 	for (i = 0; i < 2; ++i) {
1479 		if (kill(-1, death_sigs[i]) == -1 && errno == ESRCH)
1480 			return (state_func_t) single_user;
1481 
1482 		clang = 0;
1483 		alarm(DEATH_WATCH);
1484 		do
1485 			if ((pid = waitpid(-1, (int *)0, 0)) != -1)
1486 				collect_child(pid);
1487 		while (clang == 0 && errno != ECHILD);
1488 
1489 		if (errno == ECHILD)
1490 			return (state_func_t) single_user;
1491 	}
1492 
1493 	warning("some processes would not die; ps axl advised");
1494 
1495 	return (state_func_t) single_user;
1496 }
1497 
1498 /*
1499  * Run the system shutdown script.
1500  *
1501  * Exit codes:      XXX I should document more
1502  * -2       shutdown script terminated abnormally
1503  * -1       fatal error - can't run script
1504  * 0        good.
1505  * >0       some error (exit code)
1506  */
1507 int
1508 runshutdown()
1509 {
1510 	pid_t pid, wpid;
1511 	int status;
1512 	int shutdowntimeout;
1513 	size_t len;
1514 	char *argv[4];
1515 	struct sigaction sa;
1516 	struct stat sb;
1517 
1518 	/*
1519 	 * rc.shutdown is optional, so to prevent any unnecessary
1520 	 * complaints from the shell we simply don't run it if the
1521 	 * file does not exist. If the stat() here fails for other
1522 	 * reasons, we'll let the shell complain.
1523 	 */
1524 	if (stat(_PATH_RUNDOWN, &sb) == -1 && errno == ENOENT)
1525 		return 0;
1526 
1527 	if ((pid = fork()) == 0) {
1528 		int	fd;
1529 
1530 		/* Assume that init already grab console as ctty before */
1531 
1532 		sigemptyset(&sa.sa_mask);
1533 		sa.sa_flags = 0;
1534 		sa.sa_handler = SIG_IGN;
1535 		(void) sigaction(SIGTSTP, &sa, (struct sigaction *)0);
1536 		(void) sigaction(SIGHUP, &sa, (struct sigaction *)0);
1537 
1538 		if ((fd = open(_PATH_CONSOLE, O_RDWR)) == -1)
1539 		    warning("can't open %s: %m", _PATH_CONSOLE);
1540 		else {
1541 		    (void) dup2(fd, 0);
1542 		    (void) dup2(fd, 1);
1543 		    (void) dup2(fd, 2);
1544 		    if (fd > 2)
1545 			close(fd);
1546 		}
1547 
1548 		/*
1549 		 * Run the shutdown script.
1550 		 */
1551 		argv[0] = "sh";
1552 		argv[1] = _PATH_RUNDOWN;
1553 		if (Reboot)
1554 			argv[2] = "reboot";
1555 		else
1556 			argv[2] = "single";
1557 		argv[3] = 0;
1558 
1559 		sigprocmask(SIG_SETMASK, &sa.sa_mask, (sigset_t *) 0);
1560 
1561 #ifdef LOGIN_CAP
1562 		setprocresources(RESOURCE_RC);
1563 #endif
1564 		execv(_PATH_BSHELL, argv);
1565 		warning("can't exec %s for %s: %m", _PATH_BSHELL, _PATH_RUNDOWN);
1566 		_exit(1);	/* force single user mode */
1567 	}
1568 
1569 	if (pid == -1) {
1570 		emergency("can't fork for %s on %s: %m",
1571 			_PATH_BSHELL, _PATH_RUNDOWN);
1572 		while (waitpid(-1, (int *) 0, WNOHANG) > 0)
1573 			continue;
1574 		sleep(STALL_TIMEOUT);
1575 		return -1;
1576 	}
1577 
1578 	len = sizeof(shutdowntimeout);
1579 	if (sysctlbyname("kern.shutdown_timeout",
1580 			 &shutdowntimeout,
1581 			 &len, NULL, 0) == -1 || shutdowntimeout < 2)
1582 	    shutdowntimeout = DEATH_SCRIPT;
1583 	alarm(shutdowntimeout);
1584 	clang = 0;
1585 	/*
1586 	 * Copied from single_user().  This is a bit paranoid.
1587 	 * Use the same ALRM handler.
1588 	 */
1589 	do {
1590 		if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1)
1591 			collect_child(wpid);
1592 		if (clang == 1) {
1593 			/* we were waiting for the sub-shell */
1594 			kill(wpid, SIGTERM);
1595 			warning("timeout expired for %s on %s: %m; going to single used mode",
1596 				_PATH_BSHELL, _PATH_RUNDOWN);
1597 			return -1;
1598 		}
1599 		if (wpid == -1) {
1600 			if (errno == EINTR)
1601 				continue;
1602 			warning("wait for %s on %s failed: %m; going to single user mode",
1603 				_PATH_BSHELL, _PATH_RUNDOWN);
1604 			return -1;
1605 		}
1606 		if (wpid == pid && WIFSTOPPED(status)) {
1607 			warning("init: %s on %s stopped, restarting\n",
1608 				_PATH_BSHELL, _PATH_RUNDOWN);
1609 			kill(pid, SIGCONT);
1610 			wpid = -1;
1611 		}
1612 	} while (wpid != pid && !clang);
1613 
1614 	/* Turn off the alarm */
1615 	alarm(0);
1616 
1617 	if (WIFSIGNALED(status) && WTERMSIG(status) == SIGTERM &&
1618 	    requested_transition == catatonia) {
1619 		/*
1620 		 * /etc/rc.shutdown executed /sbin/reboot;
1621 		 * wait for the end quietly
1622 		 */
1623 		sigset_t s;
1624 
1625 		sigfillset(&s);
1626 		for (;;)
1627 			sigsuspend(&s);
1628 	}
1629 
1630 	if (!WIFEXITED(status)) {
1631 		warning("%s on %s terminated abnormally, going to single user mode",
1632 			_PATH_BSHELL, _PATH_RUNDOWN);
1633 		return -2;
1634 	}
1635 
1636 	if ((status = WEXITSTATUS(status)) != 0)
1637 		warning("%s returned status %d", _PATH_RUNDOWN, status);
1638 
1639 	return status;
1640 }
1641 
1642 char *
1643 strk (char *p)
1644 {
1645     static char *t;
1646     char *q;
1647     int c;
1648 
1649     if (p)
1650 	t = p;
1651     if (!t)
1652 	return 0;
1653 
1654     c = *t;
1655     while (c == ' ' || c == '\t' )
1656 	c = *++t;
1657     if (!c) {
1658 	t = 0;
1659 	return 0;
1660     }
1661     q = t;
1662     if (c == '\'') {
1663 	c = *++t;
1664 	q = t;
1665 	while (c && c != '\'')
1666 	    c = *++t;
1667 	if (!c)  /* unterminated string */
1668 	    q = t = 0;
1669 	else
1670 	    *t++ = 0;
1671     } else {
1672 	while (c && c != ' ' && c != '\t' )
1673 	    c = *++t;
1674 	*t++ = 0;
1675 	if (!c)
1676 	    t = 0;
1677     }
1678     return q;
1679 }
1680 
1681 #ifdef LOGIN_CAP
1682 void
1683 setprocresources(cname)
1684 	const char *cname;
1685 {
1686 	login_cap_t *lc;
1687 	if ((lc = login_getclassbyname(cname, NULL)) != NULL) {
1688 		setusercontext(lc, (struct passwd*)NULL, 0, LOGIN_SETPRIORITY|LOGIN_SETRESOURCES);
1689 		login_close(lc);
1690 	}
1691 }
1692 #endif
1693