xref: /freebsd/sbin/init/init.c (revision 941e286383714ef25f1ffe9ba6ae5040afdd7060)
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  * 4. Neither the name of the University nor the names of its contributors
17  *    may be used to endorse or promote products derived from this software
18  *    without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30  * SUCH DAMAGE.
31  */
32 
33 #ifndef lint
34 static const char copyright[] =
35 "@(#) Copyright (c) 1991, 1993\n\
36 	The Regents of the University of California.  All rights reserved.\n";
37 #endif /* not lint */
38 
39 #ifndef lint
40 #if 0
41 static char sccsid[] = "@(#)init.c	8.1 (Berkeley) 7/15/93";
42 #endif
43 static const char rcsid[] =
44   "$FreeBSD$";
45 #endif /* not lint */
46 
47 #include <sys/param.h>
48 #include <sys/ioctl.h>
49 #include <sys/mount.h>
50 #include <sys/sysctl.h>
51 #include <sys/wait.h>
52 #include <sys/stat.h>
53 #include <sys/uio.h>
54 
55 #include <db.h>
56 #include <errno.h>
57 #include <fcntl.h>
58 #include <kenv.h>
59 #include <libutil.h>
60 #include <paths.h>
61 #include <signal.h>
62 #include <stdio.h>
63 #include <stdlib.h>
64 #include <string.h>
65 #include <syslog.h>
66 #include <time.h>
67 #include <ttyent.h>
68 #define	_ULOG_POSIX_NAMES
69 #include <ulog.h>
70 #include <unistd.h>
71 #include <sys/reboot.h>
72 #include <err.h>
73 
74 #include <stdarg.h>
75 
76 #ifdef SECURE
77 #include <pwd.h>
78 #endif
79 
80 #ifdef LOGIN_CAP
81 #include <login_cap.h>
82 #endif
83 
84 #include "pathnames.h"
85 
86 /*
87  * Sleep times; used to prevent thrashing.
88  */
89 #define	GETTY_SPACING		 5	/* N secs minimum getty spacing */
90 #define	GETTY_SLEEP		30	/* sleep N secs after spacing problem */
91 #define	GETTY_NSPACE             3      /* max. spacing count to bring reaction */
92 #define	WINDOW_WAIT		 3	/* wait N secs after starting window */
93 #define	STALL_TIMEOUT		30	/* wait N secs after warning */
94 #define	DEATH_WATCH		10	/* wait N secs for procs to die */
95 #define	DEATH_SCRIPT		120	/* wait for 2min for /etc/rc.shutdown */
96 #define	RESOURCE_RC		"daemon"
97 #define	RESOURCE_WINDOW 	"default"
98 #define	RESOURCE_GETTY		"default"
99 
100 static void handle(sig_t, ...);
101 static void delset(sigset_t *, ...);
102 
103 static void stall(const char *, ...) __printflike(1, 2);
104 static void warning(const char *, ...) __printflike(1, 2);
105 static void emergency(const char *, ...) __printflike(1, 2);
106 static void disaster(int);
107 static void badsys(int);
108 static int  runshutdown(void);
109 static char *strk(char *);
110 
111 /*
112  * We really need a recursive typedef...
113  * The following at least guarantees that the return type of (*state_t)()
114  * is sufficiently wide to hold a function pointer.
115  */
116 typedef long (*state_func_t)(void);
117 typedef state_func_t (*state_t)(void);
118 
119 static state_func_t single_user(void);
120 static state_func_t runcom(void);
121 static state_func_t read_ttys(void);
122 static state_func_t multi_user(void);
123 static state_func_t clean_ttys(void);
124 static state_func_t catatonia(void);
125 static state_func_t death(void);
126 
127 static state_func_t run_script(const char *);
128 
129 enum { AUTOBOOT, FASTBOOT } runcom_mode = AUTOBOOT;
130 #define FALSE	0
131 #define TRUE	1
132 
133 int Reboot = FALSE;
134 int howto = RB_AUTOBOOT;
135 
136 int devfs;
137 
138 static void transition(state_t);
139 static state_t requested_transition;
140 
141 static void setctty(const char *);
142 static const char *get_shell(void);
143 static void write_stderr(const char *message);
144 
145 typedef struct init_session {
146 	int	se_index;		/* index of entry in ttys file */
147 	pid_t	se_process;		/* controlling process */
148 	time_t	se_started;		/* used to avoid thrashing */
149 	int	se_flags;		/* status of session */
150 #define	SE_SHUTDOWN	0x1		/* session won't be restarted */
151 #define	SE_PRESENT	0x2		/* session is in /etc/ttys */
152 	int     se_nspace;              /* spacing count */
153 	char	*se_device;		/* filename of port */
154 	char	*se_getty;		/* what to run on that port */
155 	char    *se_getty_argv_space;   /* pre-parsed argument array space */
156 	char	**se_getty_argv;	/* pre-parsed argument array */
157 	char	*se_window;		/* window system (started only once) */
158 	char    *se_window_argv_space;  /* pre-parsed argument array space */
159 	char	**se_window_argv;	/* pre-parsed argument array */
160 	char    *se_type;               /* default terminal type */
161 	struct	init_session *se_prev;
162 	struct	init_session *se_next;
163 } session_t;
164 
165 static void free_session(session_t *);
166 static session_t *new_session(session_t *, int, struct ttyent *);
167 static session_t *sessions;
168 
169 static char **construct_argv(char *);
170 static void start_window_system(session_t *);
171 static void collect_child(pid_t);
172 static pid_t start_getty(session_t *);
173 static void transition_handler(int);
174 static void alrm_handler(int);
175 static void setsecuritylevel(int);
176 static int getsecuritylevel(void);
177 static int setupargv(session_t *, struct ttyent *);
178 #ifdef LOGIN_CAP
179 static void setprocresources(const char *);
180 #endif
181 static int clang;
182 
183 static void clear_session_logs(session_t *);
184 
185 static int start_session_db(void);
186 static void add_session(session_t *);
187 static void del_session(session_t *);
188 static session_t *find_session(pid_t);
189 static DB *session_db;
190 
191 /*
192  * The mother of all processes.
193  */
194 int
195 main(int argc, char *argv[])
196 {
197 	state_t initial_transition = runcom;
198 	char kenv_value[PATH_MAX];
199 	int c;
200 	struct sigaction sa;
201 	sigset_t mask;
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 				char runlevel = *argv[1];
214 				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 			initial_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 	/*
287 	 * We catch or block signals rather than ignore them,
288 	 * so that they get reset on exec.
289 	 */
290 	handle(badsys, SIGSYS, 0);
291 	handle(disaster, SIGABRT, SIGFPE, SIGILL, SIGSEGV, SIGBUS, SIGXCPU,
292 	    SIGXFSZ, 0);
293 	handle(transition_handler, SIGHUP, SIGINT, SIGTERM, SIGTSTP, SIGUSR1,
294 	    SIGUSR2, 0);
295 	handle(alrm_handler, SIGALRM, 0);
296 	sigfillset(&mask);
297 	delset(&mask, SIGABRT, SIGFPE, SIGILL, SIGSEGV, SIGBUS, SIGSYS,
298 	    SIGXCPU, SIGXFSZ, SIGHUP, SIGINT, SIGTERM, SIGTSTP, SIGALRM,
299 	    SIGUSR1, SIGUSR2, 0);
300 	sigprocmask(SIG_SETMASK, &mask, (sigset_t *) 0);
301 	sigemptyset(&sa.sa_mask);
302 	sa.sa_flags = 0;
303 	sa.sa_handler = SIG_IGN;
304 	sigaction(SIGTTIN, &sa, (struct sigaction *)0);
305 	sigaction(SIGTTOU, &sa, (struct sigaction *)0);
306 
307 	/*
308 	 * Paranoia.
309 	 */
310 	close(0);
311 	close(1);
312 	close(2);
313 
314 	if (kenv(KENV_GET, "init_script", kenv_value, sizeof(kenv_value)) > 0) {
315 		state_func_t next_transition;
316 
317 		if ((next_transition = run_script(kenv_value)) != 0)
318 			initial_transition = (state_t) next_transition;
319 	}
320 
321 	if (kenv(KENV_GET, "init_chroot", kenv_value, sizeof(kenv_value)) > 0) {
322 		if (chdir(kenv_value) != 0 || chroot(".") != 0)
323 			warning("Can't chroot to %s: %m", kenv_value);
324 	}
325 
326 	/*
327 	 * Additional check if devfs needs to be mounted:
328 	 * If "/" and "/dev" have the same device number,
329 	 * then it hasn't been mounted yet.
330 	 */
331 	if (!devfs) {
332 		struct stat stst;
333 		dev_t root_devno;
334 
335 		stat("/", &stst);
336 		root_devno = stst.st_dev;
337 		if (stat("/dev", &stst) != 0)
338 			warning("Can't stat /dev: %m");
339 		else if (stst.st_dev == root_devno)
340 			devfs++;
341 	}
342 
343 	if (devfs) {
344 		struct iovec iov[4];
345 		char *s;
346 		int i;
347 
348 		char _fstype[]	= "fstype";
349 		char _devfs[]	= "devfs";
350 		char _fspath[]	= "fspath";
351 		char _path_dev[]= _PATH_DEV;
352 
353 		iov[0].iov_base = _fstype;
354 		iov[0].iov_len = sizeof(_fstype);
355 		iov[1].iov_base = _devfs;
356 		iov[1].iov_len = sizeof(_devfs);
357 		iov[2].iov_base = _fspath;
358 		iov[2].iov_len = sizeof(_fspath);
359 		/*
360 		 * Try to avoid the trailing slash in _PATH_DEV.
361 		 * Be *very* defensive.
362 		 */
363 		s = strdup(_PATH_DEV);
364 		if (s != NULL) {
365 			i = strlen(s);
366 			if (i > 0 && s[i - 1] == '/')
367 				s[i - 1] = '\0';
368 			iov[3].iov_base = s;
369 			iov[3].iov_len = strlen(s) + 1;
370 		} else {
371 			iov[3].iov_base = _path_dev;
372 			iov[3].iov_len = sizeof(_path_dev);
373 		}
374 		nmount(iov, 4, 0);
375 		if (s != NULL)
376 			free(s);
377 	}
378 
379 	/*
380 	 * Start the state machine.
381 	 */
382 	transition(initial_transition);
383 
384 	/*
385 	 * Should never reach here.
386 	 */
387 	return 1;
388 }
389 
390 /*
391  * Associate a function with a signal handler.
392  */
393 static void
394 handle(sig_t handler, ...)
395 {
396 	int sig;
397 	struct sigaction sa;
398 	sigset_t mask_everything;
399 	va_list ap;
400 	va_start(ap, handler);
401 
402 	sa.sa_handler = handler;
403 	sigfillset(&mask_everything);
404 
405 	while ((sig = va_arg(ap, int)) != 0) {
406 		sa.sa_mask = mask_everything;
407 		/* XXX SA_RESTART? */
408 		sa.sa_flags = sig == SIGCHLD ? SA_NOCLDSTOP : 0;
409 		sigaction(sig, &sa, (struct sigaction *) 0);
410 	}
411 	va_end(ap);
412 }
413 
414 /*
415  * Delete a set of signals from a mask.
416  */
417 static void
418 delset(sigset_t *maskp, ...)
419 {
420 	int sig;
421 	va_list ap;
422 	va_start(ap, maskp);
423 
424 	while ((sig = va_arg(ap, int)) != 0)
425 		sigdelset(maskp, sig);
426 	va_end(ap);
427 }
428 
429 /*
430  * Log a message and sleep for a while (to give someone an opportunity
431  * to read it and to save log or hardcopy output if the problem is chronic).
432  * NB: should send a message to the session logger to avoid blocking.
433  */
434 static void
435 stall(const char *message, ...)
436 {
437 	va_list ap;
438 	va_start(ap, message);
439 
440 	vsyslog(LOG_ALERT, message, ap);
441 	va_end(ap);
442 	sleep(STALL_TIMEOUT);
443 }
444 
445 /*
446  * Like stall(), but doesn't sleep.
447  * If cpp had variadic macros, the two functions could be #defines for another.
448  * NB: should send a message to the session logger to avoid blocking.
449  */
450 static void
451 warning(const char *message, ...)
452 {
453 	va_list ap;
454 	va_start(ap, message);
455 
456 	vsyslog(LOG_ALERT, message, ap);
457 	va_end(ap);
458 }
459 
460 /*
461  * Log an emergency message.
462  * NB: should send a message to the session logger to avoid blocking.
463  */
464 static void
465 emergency(const char *message, ...)
466 {
467 	va_list ap;
468 	va_start(ap, message);
469 
470 	vsyslog(LOG_EMERG, message, ap);
471 	va_end(ap);
472 }
473 
474 /*
475  * Catch a SIGSYS signal.
476  *
477  * These may arise if a system does not support sysctl.
478  * We tolerate up to 25 of these, then throw in the towel.
479  */
480 static void
481 badsys(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 static void
494 disaster(int sig)
495 {
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 static int
508 getsecuritylevel(void)
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 static void
532 setsecuritylevel(int newlevel)
533 {
534 #ifdef KERN_SECURELVL
535 	int name[2], curlevel;
536 
537 	curlevel = getsecuritylevel();
538 	if (newlevel == curlevel)
539 		return;
540 	name[0] = CTL_KERN;
541 	name[1] = KERN_SECURELVL;
542 	if (sysctl(name, 2, NULL, NULL, &newlevel, sizeof newlevel) == -1) {
543 		emergency(
544 		    "cannot change kernel security level from %d to %d: %s",
545 		    curlevel, newlevel, strerror(errno));
546 		return;
547 	}
548 #ifdef SECURE
549 	warning("kernel security level changed from %d to %d",
550 	    curlevel, newlevel);
551 #endif
552 #endif
553 }
554 
555 /*
556  * Change states in the finite state machine.
557  * The initial state is passed as an argument.
558  */
559 static void
560 transition(state_t s)
561 {
562 
563 	for (;;)
564 		s = (state_t) (*s)();
565 }
566 
567 /*
568  * Close out the accounting files for a login session.
569  * NB: should send a message to the session logger to avoid blocking.
570  */
571 static void
572 clear_session_logs(session_t *sp)
573 {
574 
575 	ulog_logout(sp->se_device);
576 }
577 
578 /*
579  * Start a session and allocate a controlling terminal.
580  * Only called by children of init after forking.
581  */
582 static void
583 setctty(const char *name)
584 {
585 	int fd;
586 
587 	revoke(name);
588 	if ((fd = open(name, O_RDWR)) == -1) {
589 		stall("can't open %s: %m", name);
590 		_exit(1);
591 	}
592 	if (login_tty(fd) == -1) {
593 		stall("can't get %s for controlling terminal: %m", name);
594 		_exit(1);
595 	}
596 }
597 
598 static const char *
599 get_shell(void)
600 {
601 	static char kenv_value[PATH_MAX];
602 
603 	if (kenv(KENV_GET, "init_shell", kenv_value, sizeof(kenv_value)) > 0)
604 		return kenv_value;
605 	else
606 		return _PATH_BSHELL;
607 }
608 
609 static void
610 write_stderr(const char *message)
611 {
612 
613 	write(STDERR_FILENO, message, strlen(message));
614 }
615 
616 /*
617  * Bring the system up single user.
618  */
619 static state_func_t
620 single_user(void)
621 {
622 	pid_t pid, wpid;
623 	int status;
624 	sigset_t mask;
625 	const char *shell;
626 	char *argv[2];
627 #ifdef SECURE
628 	struct ttyent *typ;
629 	struct passwd *pp;
630 	static const char banner[] =
631 		"Enter root password, or ^D to go multi-user\n";
632 	char *clear, *password;
633 #endif
634 #ifdef DEBUGSHELL
635 	char altshell[128];
636 #endif
637 
638 	if (Reboot) {
639 		/* Instead of going single user, let's reboot the machine */
640 		sync();
641 		alarm(2);
642 		pause();
643 		reboot(howto);
644 		_exit(0);
645 	}
646 
647 	shell = get_shell();
648 
649 	if ((pid = fork()) == 0) {
650 		/*
651 		 * Start the single user session.
652 		 */
653 		setctty(_PATH_CONSOLE);
654 
655 #ifdef SECURE
656 		/*
657 		 * Check the root password.
658 		 * We don't care if the console is 'on' by default;
659 		 * it's the only tty that can be 'off' and 'secure'.
660 		 */
661 		typ = getttynam("console");
662 		pp = getpwnam("root");
663 		if (typ && (typ->ty_status & TTY_SECURE) == 0 &&
664 		    pp && *pp->pw_passwd) {
665 			write_stderr(banner);
666 			for (;;) {
667 				clear = getpass("Password:");
668 				if (clear == 0 || *clear == '\0')
669 					_exit(0);
670 				password = crypt(clear, pp->pw_passwd);
671 				bzero(clear, _PASSWORD_LEN);
672 				if (strcmp(password, pp->pw_passwd) == 0)
673 					break;
674 				warning("single-user login failed\n");
675 			}
676 		}
677 		endttyent();
678 		endpwent();
679 #endif /* SECURE */
680 
681 #ifdef DEBUGSHELL
682 		{
683 			char *cp = altshell;
684 			int num;
685 
686 #define	SHREQUEST "Enter full pathname of shell or RETURN for "
687 			write_stderr(SHREQUEST);
688 			write_stderr(shell);
689 			write_stderr(": ");
690 			while ((num = read(STDIN_FILENO, cp, 1)) != -1 &&
691 			    num != 0 && *cp != '\n' && cp < &altshell[127])
692 				cp++;
693 			*cp = '\0';
694 			if (altshell[0] != '\0')
695 				shell = altshell;
696 		}
697 #endif /* DEBUGSHELL */
698 
699 		/*
700 		 * Unblock signals.
701 		 * We catch all the interesting ones,
702 		 * and those are reset to SIG_DFL on exec.
703 		 */
704 		sigemptyset(&mask);
705 		sigprocmask(SIG_SETMASK, &mask, (sigset_t *) 0);
706 
707 		/*
708 		 * Fire off a shell.
709 		 * If the default one doesn't work, try the Bourne shell.
710 		 */
711 
712 		char name[] = "-sh";
713 
714 		argv[0] = name;
715 		argv[1] = 0;
716 		execv(shell, argv);
717 		emergency("can't exec %s for single user: %m", shell);
718 		execv(_PATH_BSHELL, argv);
719 		emergency("can't exec %s for single user: %m", _PATH_BSHELL);
720 		sleep(STALL_TIMEOUT);
721 		_exit(1);
722 	}
723 
724 	if (pid == -1) {
725 		/*
726 		 * We are seriously hosed.  Do our best.
727 		 */
728 		emergency("can't fork single-user shell, trying again");
729 		while (waitpid(-1, (int *) 0, WNOHANG) > 0)
730 			continue;
731 		return (state_func_t) single_user;
732 	}
733 
734 	requested_transition = 0;
735 	do {
736 		if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1)
737 			collect_child(wpid);
738 		if (wpid == -1) {
739 			if (errno == EINTR)
740 				continue;
741 			warning("wait for single-user shell failed: %m; restarting");
742 			return (state_func_t) single_user;
743 		}
744 		if (wpid == pid && WIFSTOPPED(status)) {
745 			warning("init: shell stopped, restarting\n");
746 			kill(pid, SIGCONT);
747 			wpid = -1;
748 		}
749 	} while (wpid != pid && !requested_transition);
750 
751 	if (requested_transition)
752 		return (state_func_t) requested_transition;
753 
754 	if (!WIFEXITED(status)) {
755 		if (WTERMSIG(status) == SIGKILL) {
756 			/*
757 			 *  reboot(8) killed shell?
758 			 */
759 			warning("single user shell terminated.");
760 			sleep(STALL_TIMEOUT);
761 			_exit(0);
762 		} else {
763 			warning("single user shell terminated, restarting");
764 			return (state_func_t) single_user;
765 		}
766 	}
767 
768 	runcom_mode = FASTBOOT;
769 	return (state_func_t) runcom;
770 }
771 
772 /*
773  * Run the system startup script.
774  */
775 static state_func_t
776 runcom(void)
777 {
778 	struct utmpx utx;
779 	state_func_t next_transition;
780 
781 	if ((next_transition = run_script(_PATH_RUNCOM)) != 0)
782 		return next_transition;
783 
784 	runcom_mode = AUTOBOOT;		/* the default */
785 	/* NB: should send a message to the session logger to avoid blocking. */
786 	utx.ut_type = BOOT_TIME;
787 	gettimeofday(&utx.ut_tv, NULL);
788 	pututxline(&utx);
789 	return (state_func_t) read_ttys;
790 }
791 
792 /*
793  * Run a shell script.
794  * Returns 0 on success, otherwise the next transition to enter:
795  *  - single_user if fork/execv/waitpid failed, or if the script
796  *    terminated with a signal or exit code != 0.
797  *  - death if a SIGTERM was delivered to init(8).
798  */
799 static state_func_t
800 run_script(const char *script)
801 {
802 	pid_t pid, wpid;
803 	int status;
804 	char *argv[4];
805 	const char *shell;
806 	struct sigaction sa;
807 
808 	shell = get_shell();
809 
810 	if ((pid = fork()) == 0) {
811 		sigemptyset(&sa.sa_mask);
812 		sa.sa_flags = 0;
813 		sa.sa_handler = SIG_IGN;
814 		sigaction(SIGTSTP, &sa, (struct sigaction *)0);
815 		sigaction(SIGHUP, &sa, (struct sigaction *)0);
816 
817 		setctty(_PATH_CONSOLE);
818 
819 		char _sh[]	 	= "sh";
820 		char _autoboot[]	= "autoboot";
821 
822 		argv[0] = _sh;
823 		argv[1] = __DECONST(char *, script);
824 		argv[2] = runcom_mode == AUTOBOOT ? _autoboot : 0;
825 		argv[3] = 0;
826 
827 		sigprocmask(SIG_SETMASK, &sa.sa_mask, (sigset_t *) 0);
828 
829 #ifdef LOGIN_CAP
830 		setprocresources(RESOURCE_RC);
831 #endif
832 		execv(shell, argv);
833 		stall("can't exec %s for %s: %m", shell, script);
834 		_exit(1);	/* force single user mode */
835 	}
836 
837 	if (pid == -1) {
838 		emergency("can't fork for %s on %s: %m", shell, script);
839 		while (waitpid(-1, (int *) 0, WNOHANG) > 0)
840 			continue;
841 		sleep(STALL_TIMEOUT);
842 		return (state_func_t) single_user;
843 	}
844 
845 	/*
846 	 * Copied from single_user().  This is a bit paranoid.
847 	 */
848 	requested_transition = 0;
849 	do {
850 		if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1)
851 			collect_child(wpid);
852 		if (wpid == -1) {
853 			if (requested_transition == death)
854 				return (state_func_t) death;
855 			if (errno == EINTR)
856 				continue;
857 			warning("wait for %s on %s failed: %m; going to "
858 			    "single user mode", shell, script);
859 			return (state_func_t) single_user;
860 		}
861 		if (wpid == pid && WIFSTOPPED(status)) {
862 			warning("init: %s on %s stopped, restarting\n",
863 			    shell, script);
864 			kill(pid, SIGCONT);
865 			wpid = -1;
866 		}
867 	} while (wpid != pid);
868 
869 	if (WIFSIGNALED(status) && WTERMSIG(status) == SIGTERM &&
870 	    requested_transition == catatonia) {
871 		/* /etc/rc executed /sbin/reboot; wait for the end quietly */
872 		sigset_t s;
873 
874 		sigfillset(&s);
875 		for (;;)
876 			sigsuspend(&s);
877 	}
878 
879 	if (!WIFEXITED(status)) {
880 		warning("%s on %s terminated abnormally, going to single "
881 		    "user mode", shell, script);
882 		return (state_func_t) single_user;
883 	}
884 
885 	if (WEXITSTATUS(status))
886 		return (state_func_t) single_user;
887 
888 	return (state_func_t) 0;
889 }
890 
891 /*
892  * Open the session database.
893  *
894  * NB: We could pass in the size here; is it necessary?
895  */
896 static int
897 start_session_db(void)
898 {
899 	if (session_db && (*session_db->close)(session_db))
900 		emergency("session database close: %s", strerror(errno));
901 	if ((session_db = dbopen(NULL, O_RDWR, 0, DB_HASH, NULL)) == 0) {
902 		emergency("session database open: %s", strerror(errno));
903 		return (1);
904 	}
905 	return (0);
906 
907 }
908 
909 /*
910  * Add a new login session.
911  */
912 static void
913 add_session(session_t *sp)
914 {
915 	DBT key;
916 	DBT data;
917 
918 	key.data = &sp->se_process;
919 	key.size = sizeof sp->se_process;
920 	data.data = &sp;
921 	data.size = sizeof sp;
922 
923 	if ((*session_db->put)(session_db, &key, &data, 0))
924 		emergency("insert %d: %s", sp->se_process, strerror(errno));
925 }
926 
927 /*
928  * Delete an old login session.
929  */
930 static void
931 del_session(session_t *sp)
932 {
933 	DBT key;
934 
935 	key.data = &sp->se_process;
936 	key.size = sizeof sp->se_process;
937 
938 	if ((*session_db->del)(session_db, &key, 0))
939 		emergency("delete %d: %s", sp->se_process, strerror(errno));
940 }
941 
942 /*
943  * Look up a login session by pid.
944  */
945 static session_t *
946 find_session(pid_t pid)
947 {
948 	DBT key;
949 	DBT data;
950 	session_t *ret;
951 
952 	key.data = &pid;
953 	key.size = sizeof pid;
954 	if ((*session_db->get)(session_db, &key, &data, 0) != 0)
955 		return 0;
956 	bcopy(data.data, (char *)&ret, sizeof(ret));
957 	return ret;
958 }
959 
960 /*
961  * Construct an argument vector from a command line.
962  */
963 static char **
964 construct_argv(char *command)
965 {
966 	int argc = 0;
967 	char **argv = (char **) malloc(((strlen(command) + 1) / 2 + 1)
968 						* sizeof (char *));
969 
970 	if ((argv[argc++] = strk(command)) == 0) {
971 		free(argv);
972 		return (NULL);
973 	}
974 	while ((argv[argc++] = strk((char *) 0)) != NULL)
975 		continue;
976 	return argv;
977 }
978 
979 /*
980  * Deallocate a session descriptor.
981  */
982 static void
983 free_session(session_t *sp)
984 {
985 	free(sp->se_device);
986 	if (sp->se_getty) {
987 		free(sp->se_getty);
988 		free(sp->se_getty_argv_space);
989 		free(sp->se_getty_argv);
990 	}
991 	if (sp->se_window) {
992 		free(sp->se_window);
993 		free(sp->se_window_argv_space);
994 		free(sp->se_window_argv);
995 	}
996 	if (sp->se_type)
997 		free(sp->se_type);
998 	free(sp);
999 }
1000 
1001 /*
1002  * Allocate a new session descriptor.
1003  * Mark it SE_PRESENT.
1004  */
1005 static session_t *
1006 new_session(session_t *sprev, int session_index, struct ttyent *typ)
1007 {
1008 	session_t *sp;
1009 	int fd;
1010 
1011 	if ((typ->ty_status & TTY_ON) == 0 ||
1012 	    typ->ty_name == 0 ||
1013 	    typ->ty_getty == 0)
1014 		return 0;
1015 
1016 	sp = (session_t *) calloc(1, sizeof (session_t));
1017 
1018 	sp->se_index = session_index;
1019 	sp->se_flags |= SE_PRESENT;
1020 
1021 	sp->se_device = malloc(sizeof(_PATH_DEV) + strlen(typ->ty_name));
1022 	sprintf(sp->se_device, "%s%s", _PATH_DEV, typ->ty_name);
1023 
1024 	/*
1025 	 * Attempt to open the device, if we get "device not configured"
1026 	 * then don't add the device to the session list.
1027 	 */
1028 	if ((fd = open(sp->se_device, O_RDONLY | O_NONBLOCK, 0)) < 0) {
1029 		if (errno == ENXIO) {
1030 			free_session(sp);
1031 			return (0);
1032 		}
1033 	} else
1034 		close(fd);
1035 
1036 	if (setupargv(sp, typ) == 0) {
1037 		free_session(sp);
1038 		return (0);
1039 	}
1040 
1041 	sp->se_next = 0;
1042 	if (sprev == 0) {
1043 		sessions = sp;
1044 		sp->se_prev = 0;
1045 	} else {
1046 		sprev->se_next = sp;
1047 		sp->se_prev = sprev;
1048 	}
1049 
1050 	return sp;
1051 }
1052 
1053 /*
1054  * Calculate getty and if useful window argv vectors.
1055  */
1056 static int
1057 setupargv(session_t *sp, struct ttyent *typ)
1058 {
1059 
1060 	if (sp->se_getty) {
1061 		free(sp->se_getty);
1062 		free(sp->se_getty_argv_space);
1063 		free(sp->se_getty_argv);
1064 	}
1065 	sp->se_getty = malloc(strlen(typ->ty_getty) + strlen(typ->ty_name) + 2);
1066 	sprintf(sp->se_getty, "%s %s", typ->ty_getty, typ->ty_name);
1067 	sp->se_getty_argv_space = strdup(sp->se_getty);
1068 	sp->se_getty_argv = construct_argv(sp->se_getty_argv_space);
1069 	if (sp->se_getty_argv == 0) {
1070 		warning("can't parse getty for port %s", sp->se_device);
1071 		free(sp->se_getty);
1072 		free(sp->se_getty_argv_space);
1073 		sp->se_getty = sp->se_getty_argv_space = 0;
1074 		return (0);
1075 	}
1076 	if (sp->se_window) {
1077 		free(sp->se_window);
1078 		free(sp->se_window_argv_space);
1079 		free(sp->se_window_argv);
1080 	}
1081 	sp->se_window = sp->se_window_argv_space = 0;
1082 	sp->se_window_argv = 0;
1083 	if (typ->ty_window) {
1084 		sp->se_window = strdup(typ->ty_window);
1085 		sp->se_window_argv_space = strdup(sp->se_window);
1086 		sp->se_window_argv = construct_argv(sp->se_window_argv_space);
1087 		if (sp->se_window_argv == 0) {
1088 			warning("can't parse window for port %s",
1089 			    sp->se_device);
1090 			free(sp->se_window_argv_space);
1091 			free(sp->se_window);
1092 			sp->se_window = sp->se_window_argv_space = 0;
1093 			return (0);
1094 		}
1095 	}
1096 	if (sp->se_type)
1097 		free(sp->se_type);
1098 	sp->se_type = typ->ty_type ? strdup(typ->ty_type) : 0;
1099 	return (1);
1100 }
1101 
1102 /*
1103  * Walk the list of ttys and create sessions for each active line.
1104  */
1105 static state_func_t
1106 read_ttys(void)
1107 {
1108 	int session_index = 0;
1109 	session_t *sp, *snext;
1110 	struct ttyent *typ;
1111 
1112 	/*
1113 	 * Destroy any previous session state.
1114 	 * There shouldn't be any, but just in case...
1115 	 */
1116 	for (sp = sessions; sp; sp = snext) {
1117 		if (sp->se_process)
1118 			clear_session_logs(sp);
1119 		snext = sp->se_next;
1120 		free_session(sp);
1121 	}
1122 	sessions = 0;
1123 	if (start_session_db())
1124 		return (state_func_t) single_user;
1125 
1126 	/*
1127 	 * Allocate a session entry for each active port.
1128 	 * Note that sp starts at 0.
1129 	 */
1130 	while ((typ = getttyent()) != NULL)
1131 		if ((snext = new_session(sp, ++session_index, typ)) != NULL)
1132 			sp = snext;
1133 
1134 	endttyent();
1135 
1136 	return (state_func_t) multi_user;
1137 }
1138 
1139 /*
1140  * Start a window system running.
1141  */
1142 static void
1143 start_window_system(session_t *sp)
1144 {
1145 	pid_t pid;
1146 	sigset_t mask;
1147 	char term[64], *env[2];
1148 	int status;
1149 
1150 	if ((pid = fork()) == -1) {
1151 		emergency("can't fork for window system on port %s: %m",
1152 		    sp->se_device);
1153 		/* hope that getty fails and we can try again */
1154 		return;
1155 	}
1156 	if (pid) {
1157 		waitpid(-1, &status, 0);
1158 		return;
1159 	}
1160 
1161 	/* reparent window process to the init to not make a zombie on exit */
1162 	if ((pid = fork()) == -1) {
1163 		emergency("can't fork for window system on port %s: %m",
1164 		    sp->se_device);
1165 		_exit(1);
1166 	}
1167 	if (pid)
1168 		_exit(0);
1169 
1170 	sigemptyset(&mask);
1171 	sigprocmask(SIG_SETMASK, &mask, (sigset_t *) 0);
1172 
1173 	if (setsid() < 0)
1174 		emergency("setsid failed (window) %m");
1175 
1176 #ifdef LOGIN_CAP
1177 	setprocresources(RESOURCE_WINDOW);
1178 #endif
1179 	if (sp->se_type) {
1180 		/* Don't use malloc after fork */
1181 		strcpy(term, "TERM=");
1182 		strncat(term, sp->se_type, sizeof(term) - 6);
1183 		env[0] = term;
1184 		env[1] = 0;
1185 	}
1186 	else
1187 		env[0] = 0;
1188 	execve(sp->se_window_argv[0], sp->se_window_argv, env);
1189 	stall("can't exec window system '%s' for port %s: %m",
1190 		sp->se_window_argv[0], sp->se_device);
1191 	_exit(1);
1192 }
1193 
1194 /*
1195  * Start a login session running.
1196  */
1197 static pid_t
1198 start_getty(session_t *sp)
1199 {
1200 	pid_t pid;
1201 	sigset_t mask;
1202 	time_t current_time = time((time_t *) 0);
1203 	int too_quick = 0;
1204 	char term[64], *env[2];
1205 
1206 	if (current_time >= sp->se_started &&
1207 	    current_time - sp->se_started < GETTY_SPACING) {
1208 		if (++sp->se_nspace > GETTY_NSPACE) {
1209 			sp->se_nspace = 0;
1210 			too_quick = 1;
1211 		}
1212 	} else
1213 		sp->se_nspace = 0;
1214 
1215 	/*
1216 	 * fork(), not vfork() -- we can't afford to block.
1217 	 */
1218 	if ((pid = fork()) == -1) {
1219 		emergency("can't fork for getty on port %s: %m", sp->se_device);
1220 		return -1;
1221 	}
1222 
1223 	if (pid)
1224 		return pid;
1225 
1226 	if (too_quick) {
1227 		warning("getty repeating too quickly on port %s, sleeping %d secs",
1228 		    sp->se_device, GETTY_SLEEP);
1229 		sleep((unsigned) GETTY_SLEEP);
1230 	}
1231 
1232 	if (sp->se_window) {
1233 		start_window_system(sp);
1234 		sleep(WINDOW_WAIT);
1235 	}
1236 
1237 	sigemptyset(&mask);
1238 	sigprocmask(SIG_SETMASK, &mask, (sigset_t *) 0);
1239 
1240 #ifdef LOGIN_CAP
1241 	setprocresources(RESOURCE_GETTY);
1242 #endif
1243 	if (sp->se_type) {
1244 		/* Don't use malloc after fork */
1245 		strcpy(term, "TERM=");
1246 		strncat(term, sp->se_type, sizeof(term) - 6);
1247 		env[0] = term;
1248 		env[1] = 0;
1249 	} else
1250 		env[0] = 0;
1251 	execve(sp->se_getty_argv[0], sp->se_getty_argv, env);
1252 	stall("can't exec getty '%s' for port %s: %m",
1253 		sp->se_getty_argv[0], sp->se_device);
1254 	_exit(1);
1255 }
1256 
1257 /*
1258  * Collect exit status for a child.
1259  * If an exiting login, start a new login running.
1260  */
1261 static void
1262 collect_child(pid_t pid)
1263 {
1264 	session_t *sp, *sprev, *snext;
1265 
1266 	if (! sessions)
1267 		return;
1268 
1269 	if (! (sp = find_session(pid)))
1270 		return;
1271 
1272 	clear_session_logs(sp);
1273 	del_session(sp);
1274 	sp->se_process = 0;
1275 
1276 	if (sp->se_flags & SE_SHUTDOWN) {
1277 		if ((sprev = sp->se_prev) != NULL)
1278 			sprev->se_next = sp->se_next;
1279 		else
1280 			sessions = sp->se_next;
1281 		if ((snext = sp->se_next) != NULL)
1282 			snext->se_prev = sp->se_prev;
1283 		free_session(sp);
1284 		return;
1285 	}
1286 
1287 	if ((pid = start_getty(sp)) == -1) {
1288 		/* serious trouble */
1289 		requested_transition = clean_ttys;
1290 		return;
1291 	}
1292 
1293 	sp->se_process = pid;
1294 	sp->se_started = time((time_t *) 0);
1295 	add_session(sp);
1296 }
1297 
1298 /*
1299  * Catch a signal and request a state transition.
1300  */
1301 static void
1302 transition_handler(int sig)
1303 {
1304 
1305 	switch (sig) {
1306 	case SIGHUP:
1307 		requested_transition = clean_ttys;
1308 		break;
1309 	case SIGUSR2:
1310 		howto = RB_POWEROFF;
1311 	case SIGUSR1:
1312 		howto |= RB_HALT;
1313 	case SIGINT:
1314 		Reboot = TRUE;
1315 	case SIGTERM:
1316 		requested_transition = death;
1317 		break;
1318 	case SIGTSTP:
1319 		requested_transition = catatonia;
1320 		break;
1321 	default:
1322 		requested_transition = 0;
1323 		break;
1324 	}
1325 }
1326 
1327 /*
1328  * Take the system multiuser.
1329  */
1330 static state_func_t
1331 multi_user(void)
1332 {
1333 	pid_t pid;
1334 	session_t *sp;
1335 
1336 	requested_transition = 0;
1337 
1338 	/*
1339 	 * If the administrator has not set the security level to -1
1340 	 * to indicate that the kernel should not run multiuser in secure
1341 	 * mode, and the run script has not set a higher level of security
1342 	 * than level 1, then put the kernel into secure mode.
1343 	 */
1344 	if (getsecuritylevel() == 0)
1345 		setsecuritylevel(1);
1346 
1347 	for (sp = sessions; sp; sp = sp->se_next) {
1348 		if (sp->se_process)
1349 			continue;
1350 		if ((pid = start_getty(sp)) == -1) {
1351 			/* serious trouble */
1352 			requested_transition = clean_ttys;
1353 			break;
1354 		}
1355 		sp->se_process = pid;
1356 		sp->se_started = time((time_t *) 0);
1357 		add_session(sp);
1358 	}
1359 
1360 	while (!requested_transition)
1361 		if ((pid = waitpid(-1, (int *) 0, 0)) != -1)
1362 			collect_child(pid);
1363 
1364 	return (state_func_t) requested_transition;
1365 }
1366 
1367 /*
1368  * This is an (n*2)+(n^2) algorithm.  We hope it isn't run often...
1369  */
1370 static state_func_t
1371 clean_ttys(void)
1372 {
1373 	session_t *sp, *sprev;
1374 	struct ttyent *typ;
1375 	int session_index = 0;
1376 	int devlen;
1377 	char *old_getty, *old_window, *old_type;
1378 
1379 	/*
1380 	 * mark all sessions for death, (!SE_PRESENT)
1381 	 * as we find or create new ones they'll be marked as keepers,
1382 	 * we'll later nuke all the ones not found in /etc/ttys
1383 	 */
1384 	for (sp = sessions; sp != NULL; sp = sp->se_next)
1385 		sp->se_flags &= ~SE_PRESENT;
1386 
1387 	devlen = sizeof(_PATH_DEV) - 1;
1388 	while ((typ = getttyent()) != NULL) {
1389 		++session_index;
1390 
1391 		for (sprev = 0, sp = sessions; sp; sprev = sp, sp = sp->se_next)
1392 			if (strcmp(typ->ty_name, sp->se_device + devlen) == 0)
1393 				break;
1394 
1395 		if (sp) {
1396 			/* we want this one to live */
1397 			sp->se_flags |= SE_PRESENT;
1398 			if (sp->se_index != session_index) {
1399 				warning("port %s changed utmp index from %d to %d",
1400 				       sp->se_device, sp->se_index,
1401 				       session_index);
1402 				sp->se_index = session_index;
1403 			}
1404 			if ((typ->ty_status & TTY_ON) == 0 ||
1405 			    typ->ty_getty == 0) {
1406 				sp->se_flags |= SE_SHUTDOWN;
1407 				kill(sp->se_process, SIGHUP);
1408 				continue;
1409 			}
1410 			sp->se_flags &= ~SE_SHUTDOWN;
1411 			old_getty = sp->se_getty ? strdup(sp->se_getty) : 0;
1412 			old_window = sp->se_window ? strdup(sp->se_window) : 0;
1413 			old_type = sp->se_type ? strdup(sp->se_type) : 0;
1414 			if (setupargv(sp, typ) == 0) {
1415 				warning("can't parse getty for port %s",
1416 					sp->se_device);
1417 				sp->se_flags |= SE_SHUTDOWN;
1418 				kill(sp->se_process, SIGHUP);
1419 			}
1420 			else if (   !old_getty
1421 				 || (!old_type && sp->se_type)
1422 				 || (old_type && !sp->se_type)
1423 				 || (!old_window && sp->se_window)
1424 				 || (old_window && !sp->se_window)
1425 				 || (strcmp(old_getty, sp->se_getty) != 0)
1426 				 || (old_window && strcmp(old_window, sp->se_window) != 0)
1427 				 || (old_type && strcmp(old_type, sp->se_type) != 0)
1428 				) {
1429 				/* Don't set SE_SHUTDOWN here */
1430 				sp->se_nspace = 0;
1431 				sp->se_started = 0;
1432 				kill(sp->se_process, SIGHUP);
1433 			}
1434 			if (old_getty)
1435 				free(old_getty);
1436 			if (old_window)
1437 				free(old_window);
1438 			if (old_type)
1439 				free(old_type);
1440 			continue;
1441 		}
1442 
1443 		new_session(sprev, session_index, typ);
1444 	}
1445 
1446 	endttyent();
1447 
1448 	/*
1449 	 * sweep through and kill all deleted sessions
1450 	 * ones who's /etc/ttys line was deleted (SE_PRESENT unset)
1451 	 */
1452 	for (sp = sessions; sp != NULL; sp = sp->se_next) {
1453 		if ((sp->se_flags & SE_PRESENT) == 0) {
1454 			sp->se_flags |= SE_SHUTDOWN;
1455 			kill(sp->se_process, SIGHUP);
1456 		}
1457 	}
1458 
1459 	return (state_func_t) multi_user;
1460 }
1461 
1462 /*
1463  * Block further logins.
1464  */
1465 static state_func_t
1466 catatonia(void)
1467 {
1468 	session_t *sp;
1469 
1470 	for (sp = sessions; sp; sp = sp->se_next)
1471 		sp->se_flags |= SE_SHUTDOWN;
1472 
1473 	return (state_func_t) multi_user;
1474 }
1475 
1476 /*
1477  * Note SIGALRM.
1478  */
1479 static void
1480 alrm_handler(int sig)
1481 {
1482 
1483 	(void)sig;
1484 	clang = 1;
1485 }
1486 
1487 /*
1488  * Bring the system down to single user.
1489  */
1490 static state_func_t
1491 death(void)
1492 {
1493 	struct utmpx utx;
1494 	session_t *sp;
1495 	int i;
1496 	pid_t pid;
1497 	static const int death_sigs[2] = { SIGTERM, SIGKILL };
1498 
1499 	/* NB: should send a message to the session logger to avoid blocking. */
1500 	utx.ut_type = SHUTDOWN_TIME;
1501 	gettimeofday(&utx.ut_tv, NULL);
1502 	pututxline(&utx);
1503 
1504 	/*
1505 	 * Also revoke the TTY here.  Because runshutdown() may reopen
1506 	 * the TTY whose getty we're killing here, there is no guarantee
1507 	 * runshutdown() will perform the initial open() call, causing
1508 	 * the terminal attributes to be misconfigured.
1509 	 */
1510 	for (sp = sessions; sp; sp = sp->se_next) {
1511 		sp->se_flags |= SE_SHUTDOWN;
1512 		kill(sp->se_process, SIGHUP);
1513 		revoke(sp->se_device);
1514 	}
1515 
1516 	/* Try to run the rc.shutdown script within a period of time */
1517 	runshutdown();
1518 
1519 	for (i = 0; i < 2; ++i) {
1520 		if (kill(-1, death_sigs[i]) == -1 && errno == ESRCH)
1521 			return (state_func_t) single_user;
1522 
1523 		clang = 0;
1524 		alarm(DEATH_WATCH);
1525 		do
1526 			if ((pid = waitpid(-1, (int *)0, 0)) != -1)
1527 				collect_child(pid);
1528 		while (clang == 0 && errno != ECHILD);
1529 
1530 		if (errno == ECHILD)
1531 			return (state_func_t) single_user;
1532 	}
1533 
1534 	warning("some processes would not die; ps axl advised");
1535 
1536 	return (state_func_t) single_user;
1537 }
1538 
1539 /*
1540  * Run the system shutdown script.
1541  *
1542  * Exit codes:      XXX I should document more
1543  * -2       shutdown script terminated abnormally
1544  * -1       fatal error - can't run script
1545  * 0        good.
1546  * >0       some error (exit code)
1547  */
1548 static int
1549 runshutdown(void)
1550 {
1551 	pid_t pid, wpid;
1552 	int status;
1553 	int shutdowntimeout;
1554 	size_t len;
1555 	char *argv[4];
1556 	const char *shell;
1557 	struct sigaction sa;
1558 	struct stat sb;
1559 
1560 	/*
1561 	 * rc.shutdown is optional, so to prevent any unnecessary
1562 	 * complaints from the shell we simply don't run it if the
1563 	 * file does not exist. If the stat() here fails for other
1564 	 * reasons, we'll let the shell complain.
1565 	 */
1566 	if (stat(_PATH_RUNDOWN, &sb) == -1 && errno == ENOENT)
1567 		return 0;
1568 
1569 	shell = get_shell();
1570 
1571 	if ((pid = fork()) == 0) {
1572 		sigemptyset(&sa.sa_mask);
1573 		sa.sa_flags = 0;
1574 		sa.sa_handler = SIG_IGN;
1575 		sigaction(SIGTSTP, &sa, (struct sigaction *)0);
1576 		sigaction(SIGHUP, &sa, (struct sigaction *)0);
1577 
1578 		setctty(_PATH_CONSOLE);
1579 
1580 		char _sh[]	= "sh";
1581 		char _reboot[]	= "reboot";
1582 		char _single[]	= "single";
1583 		char _path_rundown[] = _PATH_RUNDOWN;
1584 
1585 		argv[0] = _sh;
1586 		argv[1] = _path_rundown;
1587 		argv[2] = Reboot ? _reboot : _single;
1588 		argv[3] = 0;
1589 
1590 		sigprocmask(SIG_SETMASK, &sa.sa_mask, (sigset_t *) 0);
1591 
1592 #ifdef LOGIN_CAP
1593 		setprocresources(RESOURCE_RC);
1594 #endif
1595 		execv(shell, argv);
1596 		warning("can't exec %s for %s: %m", shell, _PATH_RUNDOWN);
1597 		_exit(1);	/* force single user mode */
1598 	}
1599 
1600 	if (pid == -1) {
1601 		emergency("can't fork for %s on %s: %m", shell, _PATH_RUNDOWN);
1602 		while (waitpid(-1, (int *) 0, WNOHANG) > 0)
1603 			continue;
1604 		sleep(STALL_TIMEOUT);
1605 		return -1;
1606 	}
1607 
1608 	len = sizeof(shutdowntimeout);
1609 	if (sysctlbyname("kern.init_shutdown_timeout", &shutdowntimeout, &len,
1610 	    NULL, 0) == -1 || shutdowntimeout < 2)
1611 		shutdowntimeout = DEATH_SCRIPT;
1612 	alarm(shutdowntimeout);
1613 	clang = 0;
1614 	/*
1615 	 * Copied from single_user().  This is a bit paranoid.
1616 	 * Use the same ALRM handler.
1617 	 */
1618 	do {
1619 		if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1)
1620 			collect_child(wpid);
1621 		if (clang == 1) {
1622 			/* we were waiting for the sub-shell */
1623 			kill(wpid, SIGTERM);
1624 			warning("timeout expired for %s on %s: %m; going to "
1625 			    "single user mode", shell, _PATH_RUNDOWN);
1626 			return -1;
1627 		}
1628 		if (wpid == -1) {
1629 			if (errno == EINTR)
1630 				continue;
1631 			warning("wait for %s on %s failed: %m; going to "
1632 			    "single user mode", shell, _PATH_RUNDOWN);
1633 			return -1;
1634 		}
1635 		if (wpid == pid && WIFSTOPPED(status)) {
1636 			warning("init: %s on %s stopped, restarting\n",
1637 				shell, _PATH_RUNDOWN);
1638 			kill(pid, SIGCONT);
1639 			wpid = -1;
1640 		}
1641 	} while (wpid != pid && !clang);
1642 
1643 	/* Turn off the alarm */
1644 	alarm(0);
1645 
1646 	if (WIFSIGNALED(status) && WTERMSIG(status) == SIGTERM &&
1647 	    requested_transition == catatonia) {
1648 		/*
1649 		 * /etc/rc.shutdown executed /sbin/reboot;
1650 		 * wait for the end quietly
1651 		 */
1652 		sigset_t s;
1653 
1654 		sigfillset(&s);
1655 		for (;;)
1656 			sigsuspend(&s);
1657 	}
1658 
1659 	if (!WIFEXITED(status)) {
1660 		warning("%s on %s terminated abnormally, going to "
1661 		    "single user mode", shell, _PATH_RUNDOWN);
1662 		return -2;
1663 	}
1664 
1665 	if ((status = WEXITSTATUS(status)) != 0)
1666 		warning("%s returned status %d", _PATH_RUNDOWN, status);
1667 
1668 	return status;
1669 }
1670 
1671 static char *
1672 strk(char *p)
1673 {
1674 	static char *t;
1675 	char *q;
1676 	int c;
1677 
1678 	if (p)
1679 		t = p;
1680 	if (!t)
1681 		return 0;
1682 
1683 	c = *t;
1684 	while (c == ' ' || c == '\t' )
1685 		c = *++t;
1686 	if (!c) {
1687 		t = 0;
1688 		return 0;
1689 	}
1690 	q = t;
1691 	if (c == '\'') {
1692 		c = *++t;
1693 		q = t;
1694 		while (c && c != '\'')
1695 			c = *++t;
1696 		if (!c)  /* unterminated string */
1697 			q = t = 0;
1698 		else
1699 			*t++ = 0;
1700 	} else {
1701 		while (c && c != ' ' && c != '\t' )
1702 			c = *++t;
1703 		*t++ = 0;
1704 		if (!c)
1705 			t = 0;
1706 	}
1707 	return q;
1708 }
1709 
1710 #ifdef LOGIN_CAP
1711 static void
1712 setprocresources(const char *cname)
1713 {
1714 	login_cap_t *lc;
1715 	if ((lc = login_getclassbyname(cname, NULL)) != NULL) {
1716 		setusercontext(lc, (struct passwd*)NULL, 0,
1717 		    LOGIN_SETPRIORITY | LOGIN_SETRESOURCES);
1718 		login_close(lc);
1719 	}
1720 }
1721 #endif
1722