xref: /freebsd/sbin/init/init.c (revision 7431dfd4580e850375fe5478d92ec770344db098)
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 #include <unistd.h>
69 #include <sys/reboot.h>
70 #include <err.h>
71 
72 #include <stdarg.h>
73 
74 #ifdef SECURE
75 #include <pwd.h>
76 #endif
77 
78 #ifdef LOGIN_CAP
79 #include <login_cap.h>
80 #endif
81 
82 #include "pathnames.h"
83 
84 /*
85  * Sleep times; used to prevent thrashing.
86  */
87 #define	GETTY_SPACING		 5	/* N secs minimum getty spacing */
88 #define	GETTY_SLEEP		30	/* sleep N secs after spacing problem */
89 #define	GETTY_NSPACE		 3	/* max. spacing count to bring reaction */
90 #define	WINDOW_WAIT		 3	/* wait N secs after starting window */
91 #define	STALL_TIMEOUT		30	/* wait N secs after warning */
92 #define	DEATH_WATCH		10	/* wait N secs for procs to die */
93 #define	DEATH_SCRIPT		120	/* wait for 2min for /etc/rc.shutdown */
94 #define	RESOURCE_RC		"daemon"
95 #define	RESOURCE_WINDOW		"default"
96 #define	RESOURCE_GETTY		"default"
97 
98 static void handle(sig_t, ...);
99 static void delset(sigset_t *, ...);
100 
101 static void stall(const char *, ...) __printflike(1, 2);
102 static void warning(const char *, ...) __printflike(1, 2);
103 static void emergency(const char *, ...) __printflike(1, 2);
104 static void disaster(int);
105 static void badsys(int);
106 static int  runshutdown(void);
107 static char *strk(char *);
108 
109 /*
110  * We really need a recursive typedef...
111  * The following at least guarantees that the return type of (*state_t)()
112  * is sufficiently wide to hold a function pointer.
113  */
114 typedef long (*state_func_t)(void);
115 typedef state_func_t (*state_t)(void);
116 
117 static state_func_t single_user(void);
118 static state_func_t runcom(void);
119 static state_func_t read_ttys(void);
120 static state_func_t multi_user(void);
121 static state_func_t clean_ttys(void);
122 static state_func_t catatonia(void);
123 static state_func_t death(void);
124 static state_func_t death_single(void);
125 
126 static state_func_t run_script(const char *);
127 
128 static enum { AUTOBOOT, FASTBOOT } runcom_mode = AUTOBOOT;
129 #define FALSE	0
130 #define TRUE	1
131 
132 static int Reboot = FALSE;
133 static int howto = RB_AUTOBOOT;
134 
135 static int devfs;
136 
137 static void transition(state_t);
138 static state_t requested_transition;
139 static state_t current_state = death_single;
140 
141 static void open_console(void);
142 static const char *get_shell(void);
143 static void write_stderr(const char *message);
144 
145 typedef struct init_session {
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 static void free_session(session_t *);
165 static session_t *new_session(session_t *, struct ttyent *);
166 static session_t *sessions;
167 
168 static char **construct_argv(char *);
169 static void start_window_system(session_t *);
170 static void collect_child(pid_t);
171 static pid_t start_getty(session_t *);
172 static void transition_handler(int);
173 static void alrm_handler(int);
174 static void setsecuritylevel(int);
175 static int getsecuritylevel(void);
176 static int setupargv(session_t *, struct ttyent *);
177 #ifdef LOGIN_CAP
178 static void setprocresources(const char *);
179 #endif
180 static int clang;
181 
182 static int start_session_db(void);
183 static void add_session(session_t *);
184 static void del_session(session_t *);
185 static session_t *find_session(pid_t);
186 static DB *session_db;
187 
188 /*
189  * The mother of all processes.
190  */
191 int
192 main(int argc, char *argv[])
193 {
194 	state_t initial_transition = runcom;
195 	char kenv_value[PATH_MAX];
196 	int c;
197 	struct sigaction sa;
198 	sigset_t mask;
199 
200 	/* Dispose of random users. */
201 	if (getuid() != 0)
202 		errx(1, "%s", strerror(EPERM));
203 
204 	/* System V users like to reexec init. */
205 	if (getpid() != 1) {
206 #ifdef COMPAT_SYSV_INIT
207 		/* So give them what they want */
208 		if (argc > 1) {
209 			if (strlen(argv[1]) == 1) {
210 				char runlevel = *argv[1];
211 				int sig;
212 
213 				switch (runlevel) {
214 				case '0': /* halt + poweroff */
215 					sig = SIGUSR2;
216 					break;
217 				case '1': /* single-user */
218 					sig = SIGTERM;
219 					break;
220 				case '6': /* reboot */
221 					sig = SIGINT;
222 					break;
223 				case 'c': /* block further logins */
224 					sig = SIGTSTP;
225 					break;
226 				case 'q': /* rescan /etc/ttys */
227 					sig = SIGHUP;
228 					break;
229 				default:
230 					goto invalid;
231 				}
232 				kill(1, sig);
233 				_exit(0);
234 			} else
235 invalid:
236 				errx(1, "invalid run-level ``%s''", argv[1]);
237 		} else
238 #endif
239 			errx(1, "already running");
240 	}
241 	/*
242 	 * Note that this does NOT open a file...
243 	 * Does 'init' deserve its own facility number?
244 	 */
245 	openlog("init", LOG_CONS, LOG_AUTH);
246 
247 	/*
248 	 * Create an initial session.
249 	 */
250 	if (setsid() < 0)
251 		warning("initial setsid() failed: %m");
252 
253 	/*
254 	 * Establish an initial user so that programs running
255 	 * single user do not freak out and die (like passwd).
256 	 */
257 	if (setlogin("root") < 0)
258 		warning("setlogin() failed: %m");
259 
260 	/*
261 	 * This code assumes that we always get arguments through flags,
262 	 * never through bits set in some random machine register.
263 	 */
264 	while ((c = getopt(argc, argv, "dsf")) != -1)
265 		switch (c) {
266 		case 'd':
267 			devfs = 1;
268 			break;
269 		case 's':
270 			initial_transition = single_user;
271 			break;
272 		case 'f':
273 			runcom_mode = FASTBOOT;
274 			break;
275 		default:
276 			warning("unrecognized flag '-%c'", c);
277 			break;
278 		}
279 
280 	if (optind != argc)
281 		warning("ignoring excess arguments");
282 
283 	/*
284 	 * We catch or block signals rather than ignore them,
285 	 * so that they get reset on exec.
286 	 */
287 	handle(badsys, SIGSYS, 0);
288 	handle(disaster, SIGABRT, SIGFPE, SIGILL, SIGSEGV, SIGBUS, SIGXCPU,
289 	    SIGXFSZ, 0);
290 	handle(transition_handler, SIGHUP, SIGINT, SIGTERM, SIGTSTP, SIGUSR1,
291 	    SIGUSR2, 0);
292 	handle(alrm_handler, SIGALRM, 0);
293 	sigfillset(&mask);
294 	delset(&mask, SIGABRT, SIGFPE, SIGILL, SIGSEGV, SIGBUS, SIGSYS,
295 	    SIGXCPU, SIGXFSZ, SIGHUP, SIGINT, SIGTERM, SIGTSTP, SIGALRM,
296 	    SIGUSR1, SIGUSR2, 0);
297 	sigprocmask(SIG_SETMASK, &mask, (sigset_t *) 0);
298 	sigemptyset(&sa.sa_mask);
299 	sa.sa_flags = 0;
300 	sa.sa_handler = SIG_IGN;
301 	sigaction(SIGTTIN, &sa, (struct sigaction *)0);
302 	sigaction(SIGTTOU, &sa, (struct sigaction *)0);
303 
304 	/*
305 	 * Paranoia.
306 	 */
307 	close(0);
308 	close(1);
309 	close(2);
310 
311 	if (kenv(KENV_GET, "init_script", kenv_value, sizeof(kenv_value)) > 0) {
312 		state_func_t next_transition;
313 
314 		if ((next_transition = run_script(kenv_value)) != 0)
315 			initial_transition = (state_t) next_transition;
316 	}
317 
318 	if (kenv(KENV_GET, "init_chroot", kenv_value, sizeof(kenv_value)) > 0) {
319 		if (chdir(kenv_value) != 0 || chroot(".") != 0)
320 			warning("Can't chroot to %s: %m", kenv_value);
321 	}
322 
323 	/*
324 	 * Additional check if devfs needs to be mounted:
325 	 * If "/" and "/dev" have the same device number,
326 	 * then it hasn't been mounted yet.
327 	 */
328 	if (!devfs) {
329 		struct stat stst;
330 		dev_t root_devno;
331 
332 		stat("/", &stst);
333 		root_devno = stst.st_dev;
334 		if (stat("/dev", &stst) != 0)
335 			warning("Can't stat /dev: %m");
336 		else if (stst.st_dev == root_devno)
337 			devfs++;
338 	}
339 
340 	if (devfs) {
341 		struct iovec iov[4];
342 		char *s;
343 		int i;
344 
345 		char _fstype[]	= "fstype";
346 		char _devfs[]	= "devfs";
347 		char _fspath[]	= "fspath";
348 		char _path_dev[]= _PATH_DEV;
349 
350 		iov[0].iov_base = _fstype;
351 		iov[0].iov_len = sizeof(_fstype);
352 		iov[1].iov_base = _devfs;
353 		iov[1].iov_len = sizeof(_devfs);
354 		iov[2].iov_base = _fspath;
355 		iov[2].iov_len = sizeof(_fspath);
356 		/*
357 		 * Try to avoid the trailing slash in _PATH_DEV.
358 		 * Be *very* defensive.
359 		 */
360 		s = strdup(_PATH_DEV);
361 		if (s != NULL) {
362 			i = strlen(s);
363 			if (i > 0 && s[i - 1] == '/')
364 				s[i - 1] = '\0';
365 			iov[3].iov_base = s;
366 			iov[3].iov_len = strlen(s) + 1;
367 		} else {
368 			iov[3].iov_base = _path_dev;
369 			iov[3].iov_len = sizeof(_path_dev);
370 		}
371 		nmount(iov, 4, 0);
372 		if (s != NULL)
373 			free(s);
374 	}
375 
376 	/*
377 	 * Start the state machine.
378 	 */
379 	transition(initial_transition);
380 
381 	/*
382 	 * Should never reach here.
383 	 */
384 	return 1;
385 }
386 
387 /*
388  * Associate a function with a signal handler.
389  */
390 static void
391 handle(sig_t handler, ...)
392 {
393 	int sig;
394 	struct sigaction sa;
395 	sigset_t mask_everything;
396 	va_list ap;
397 	va_start(ap, handler);
398 
399 	sa.sa_handler = handler;
400 	sigfillset(&mask_everything);
401 
402 	while ((sig = va_arg(ap, int)) != 0) {
403 		sa.sa_mask = mask_everything;
404 		/* XXX SA_RESTART? */
405 		sa.sa_flags = sig == SIGCHLD ? SA_NOCLDSTOP : 0;
406 		sigaction(sig, &sa, (struct sigaction *) 0);
407 	}
408 	va_end(ap);
409 }
410 
411 /*
412  * Delete a set of signals from a mask.
413  */
414 static void
415 delset(sigset_t *maskp, ...)
416 {
417 	int sig;
418 	va_list ap;
419 	va_start(ap, maskp);
420 
421 	while ((sig = va_arg(ap, int)) != 0)
422 		sigdelset(maskp, sig);
423 	va_end(ap);
424 }
425 
426 /*
427  * Log a message and sleep for a while (to give someone an opportunity
428  * to read it and to save log or hardcopy output if the problem is chronic).
429  * NB: should send a message to the session logger to avoid blocking.
430  */
431 static void
432 stall(const char *message, ...)
433 {
434 	va_list ap;
435 	va_start(ap, message);
436 
437 	vsyslog(LOG_ALERT, message, ap);
438 	va_end(ap);
439 	sleep(STALL_TIMEOUT);
440 }
441 
442 /*
443  * Like stall(), but doesn't sleep.
444  * If cpp had variadic macros, the two functions could be #defines for another.
445  * NB: should send a message to the session logger to avoid blocking.
446  */
447 static void
448 warning(const char *message, ...)
449 {
450 	va_list ap;
451 	va_start(ap, message);
452 
453 	vsyslog(LOG_ALERT, message, ap);
454 	va_end(ap);
455 }
456 
457 /*
458  * Log an emergency message.
459  * NB: should send a message to the session logger to avoid blocking.
460  */
461 static void
462 emergency(const char *message, ...)
463 {
464 	va_list ap;
465 	va_start(ap, message);
466 
467 	vsyslog(LOG_EMERG, message, ap);
468 	va_end(ap);
469 }
470 
471 /*
472  * Catch a SIGSYS signal.
473  *
474  * These may arise if a system does not support sysctl.
475  * We tolerate up to 25 of these, then throw in the towel.
476  */
477 static void
478 badsys(int sig)
479 {
480 	static int badcount = 0;
481 
482 	if (badcount++ < 25)
483 		return;
484 	disaster(sig);
485 }
486 
487 /*
488  * Catch an unexpected signal.
489  */
490 static void
491 disaster(int sig)
492 {
493 
494 	emergency("fatal signal: %s",
495 	    (unsigned)sig < NSIG ? sys_siglist[sig] : "unknown signal");
496 
497 	sleep(STALL_TIMEOUT);
498 	_exit(sig);		/* reboot */
499 }
500 
501 /*
502  * Get the security level of the kernel.
503  */
504 static int
505 getsecuritylevel(void)
506 {
507 #ifdef KERN_SECURELVL
508 	int name[2], curlevel;
509 	size_t len;
510 
511 	name[0] = CTL_KERN;
512 	name[1] = KERN_SECURELVL;
513 	len = sizeof curlevel;
514 	if (sysctl(name, 2, &curlevel, &len, NULL, 0) == -1) {
515 		emergency("cannot get kernel security level: %s",
516 		    strerror(errno));
517 		return (-1);
518 	}
519 	return (curlevel);
520 #else
521 	return (-1);
522 #endif
523 }
524 
525 /*
526  * Set the security level of the kernel.
527  */
528 static void
529 setsecuritylevel(int newlevel)
530 {
531 #ifdef KERN_SECURELVL
532 	int name[2], curlevel;
533 
534 	curlevel = getsecuritylevel();
535 	if (newlevel == curlevel)
536 		return;
537 	name[0] = CTL_KERN;
538 	name[1] = KERN_SECURELVL;
539 	if (sysctl(name, 2, NULL, NULL, &newlevel, sizeof newlevel) == -1) {
540 		emergency(
541 		    "cannot change kernel security level from %d to %d: %s",
542 		    curlevel, newlevel, strerror(errno));
543 		return;
544 	}
545 #ifdef SECURE
546 	warning("kernel security level changed from %d to %d",
547 	    curlevel, newlevel);
548 #endif
549 #endif
550 }
551 
552 /*
553  * Change states in the finite state machine.
554  * The initial state is passed as an argument.
555  */
556 static void
557 transition(state_t s)
558 {
559 
560 	current_state = s;
561 	for (;;)
562 		current_state = (state_t) (*current_state)();
563 }
564 
565 /*
566  * Start a session and allocate a controlling terminal.
567  * Only called by children of init after forking.
568  */
569 static void
570 open_console(void)
571 {
572 	int fd;
573 
574 	/*
575 	 * Try to open /dev/console.  Open the device with O_NONBLOCK to
576 	 * prevent potential blocking on a carrier.
577 	 */
578 	revoke(_PATH_CONSOLE);
579 	if ((fd = open(_PATH_CONSOLE, O_RDWR | O_NONBLOCK)) != -1) {
580 		(void)fcntl(fd, F_SETFL, fcntl(fd, F_GETFL) & ~O_NONBLOCK);
581 		if (login_tty(fd) == 0)
582 			return;
583 		close(fd);
584 	}
585 
586 	/* No luck.  Log output to file if possible. */
587 	if ((fd = open(_PATH_DEVNULL, O_RDWR)) == -1) {
588 		stall("cannot open null device.");
589 		_exit(1);
590 	}
591 	if (fd != STDIN_FILENO) {
592 		dup2(fd, STDIN_FILENO);
593 		close(fd);
594 	}
595 	fd = open(_PATH_INITLOG, O_WRONLY | O_APPEND | O_CREAT, 0644);
596 	if (fd == -1)
597 		dup2(STDIN_FILENO, STDOUT_FILENO);
598 	else if (fd != STDOUT_FILENO) {
599 		dup2(fd, STDOUT_FILENO);
600 		close(fd);
601 	}
602 	dup2(STDOUT_FILENO, STDERR_FILENO);
603 }
604 
605 static const char *
606 get_shell(void)
607 {
608 	static char kenv_value[PATH_MAX];
609 
610 	if (kenv(KENV_GET, "init_shell", kenv_value, sizeof(kenv_value)) > 0)
611 		return kenv_value;
612 	else
613 		return _PATH_BSHELL;
614 }
615 
616 static void
617 write_stderr(const char *message)
618 {
619 
620 	write(STDERR_FILENO, message, strlen(message));
621 }
622 
623 /*
624  * Bring the system up single user.
625  */
626 static state_func_t
627 single_user(void)
628 {
629 	pid_t pid, wpid;
630 	int status;
631 	sigset_t mask;
632 	const char *shell;
633 	char *argv[2];
634 #ifdef SECURE
635 	struct ttyent *typ;
636 	struct passwd *pp;
637 	static const char banner[] =
638 		"Enter root password, or ^D to go multi-user\n";
639 	char *clear, *password;
640 #endif
641 #ifdef DEBUGSHELL
642 	char altshell[128];
643 #endif
644 
645 	if (Reboot) {
646 		/* Instead of going single user, let's reboot the machine */
647 		sync();
648 		reboot(howto);
649 		_exit(0);
650 	}
651 
652 	shell = get_shell();
653 
654 	if ((pid = fork()) == 0) {
655 		/*
656 		 * Start the single user session.
657 		 */
658 		open_console();
659 
660 #ifdef SECURE
661 		/*
662 		 * Check the root password.
663 		 * We don't care if the console is 'on' by default;
664 		 * it's the only tty that can be 'off' and 'secure'.
665 		 */
666 		typ = getttynam("console");
667 		pp = getpwnam("root");
668 		if (typ && (typ->ty_status & TTY_SECURE) == 0 &&
669 		    pp && *pp->pw_passwd) {
670 			write_stderr(banner);
671 			for (;;) {
672 				clear = getpass("Password:");
673 				if (clear == 0 || *clear == '\0')
674 					_exit(0);
675 				password = crypt(clear, pp->pw_passwd);
676 				bzero(clear, _PASSWORD_LEN);
677 				if (password == NULL ||
678 				    strcmp(password, pp->pw_passwd) == 0)
679 					break;
680 				warning("single-user login failed\n");
681 			}
682 		}
683 		endttyent();
684 		endpwent();
685 #endif /* SECURE */
686 
687 #ifdef DEBUGSHELL
688 		{
689 			char *cp = altshell;
690 			int num;
691 
692 #define	SHREQUEST "Enter full pathname of shell or RETURN for "
693 			write_stderr(SHREQUEST);
694 			write_stderr(shell);
695 			write_stderr(": ");
696 			while ((num = read(STDIN_FILENO, cp, 1)) != -1 &&
697 			    num != 0 && *cp != '\n' && cp < &altshell[127])
698 				cp++;
699 			*cp = '\0';
700 			if (altshell[0] != '\0')
701 				shell = altshell;
702 		}
703 #endif /* DEBUGSHELL */
704 
705 		/*
706 		 * Unblock signals.
707 		 * We catch all the interesting ones,
708 		 * and those are reset to SIG_DFL on exec.
709 		 */
710 		sigemptyset(&mask);
711 		sigprocmask(SIG_SETMASK, &mask, (sigset_t *) 0);
712 
713 		/*
714 		 * Fire off a shell.
715 		 * If the default one doesn't work, try the Bourne shell.
716 		 */
717 
718 		char name[] = "-sh";
719 
720 		argv[0] = name;
721 		argv[1] = 0;
722 		execv(shell, argv);
723 		emergency("can't exec %s for single user: %m", shell);
724 		execv(_PATH_BSHELL, argv);
725 		emergency("can't exec %s for single user: %m", _PATH_BSHELL);
726 		sleep(STALL_TIMEOUT);
727 		_exit(1);
728 	}
729 
730 	if (pid == -1) {
731 		/*
732 		 * We are seriously hosed.  Do our best.
733 		 */
734 		emergency("can't fork single-user shell, trying again");
735 		while (waitpid(-1, (int *) 0, WNOHANG) > 0)
736 			continue;
737 		return (state_func_t) single_user;
738 	}
739 
740 	requested_transition = 0;
741 	do {
742 		if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1)
743 			collect_child(wpid);
744 		if (wpid == -1) {
745 			if (errno == EINTR)
746 				continue;
747 			warning("wait for single-user shell failed: %m; restarting");
748 			return (state_func_t) single_user;
749 		}
750 		if (wpid == pid && WIFSTOPPED(status)) {
751 			warning("init: shell stopped, restarting\n");
752 			kill(pid, SIGCONT);
753 			wpid = -1;
754 		}
755 	} while (wpid != pid && !requested_transition);
756 
757 	if (requested_transition)
758 		return (state_func_t) requested_transition;
759 
760 	if (!WIFEXITED(status)) {
761 		if (WTERMSIG(status) == SIGKILL) {
762 			/*
763 			 *  reboot(8) killed shell?
764 			 */
765 			warning("single user shell terminated.");
766 			sleep(STALL_TIMEOUT);
767 			_exit(0);
768 		} else {
769 			warning("single user shell terminated, restarting");
770 			return (state_func_t) single_user;
771 		}
772 	}
773 
774 	runcom_mode = FASTBOOT;
775 	return (state_func_t) runcom;
776 }
777 
778 /*
779  * Run the system startup script.
780  */
781 static state_func_t
782 runcom(void)
783 {
784 	state_func_t next_transition;
785 
786 	if ((next_transition = run_script(_PATH_RUNCOM)) != 0)
787 		return next_transition;
788 
789 	runcom_mode = AUTOBOOT;		/* the default */
790 	return (state_func_t) read_ttys;
791 }
792 
793 /*
794  * Run a shell script.
795  * Returns 0 on success, otherwise the next transition to enter:
796  *  - single_user if fork/execv/waitpid failed, or if the script
797  *    terminated with a signal or exit code != 0.
798  *  - death_single if a SIGTERM was delivered to init(8).
799  */
800 static state_func_t
801 run_script(const char *script)
802 {
803 	pid_t pid, wpid;
804 	int status;
805 	char *argv[4];
806 	const char *shell;
807 	struct sigaction sa;
808 
809 	shell = get_shell();
810 
811 	if ((pid = fork()) == 0) {
812 		sigemptyset(&sa.sa_mask);
813 		sa.sa_flags = 0;
814 		sa.sa_handler = SIG_IGN;
815 		sigaction(SIGTSTP, &sa, (struct sigaction *)0);
816 		sigaction(SIGHUP, &sa, (struct sigaction *)0);
817 
818 		open_console();
819 
820 		char _sh[]		= "sh";
821 		char _autoboot[]	= "autoboot";
822 
823 		argv[0] = _sh;
824 		argv[1] = __DECONST(char *, script);
825 		argv[2] = runcom_mode == AUTOBOOT ? _autoboot : 0;
826 		argv[3] = 0;
827 
828 		sigprocmask(SIG_SETMASK, &sa.sa_mask, (sigset_t *) 0);
829 
830 #ifdef LOGIN_CAP
831 		setprocresources(RESOURCE_RC);
832 #endif
833 		execv(shell, argv);
834 		stall("can't exec %s for %s: %m", shell, script);
835 		_exit(1);	/* force single user mode */
836 	}
837 
838 	if (pid == -1) {
839 		emergency("can't fork for %s on %s: %m", shell, script);
840 		while (waitpid(-1, (int *) 0, WNOHANG) > 0)
841 			continue;
842 		sleep(STALL_TIMEOUT);
843 		return (state_func_t) single_user;
844 	}
845 
846 	/*
847 	 * Copied from single_user().  This is a bit paranoid.
848 	 */
849 	requested_transition = 0;
850 	do {
851 		if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1)
852 			collect_child(wpid);
853 		if (wpid == -1) {
854 			if (requested_transition == death_single)
855 				return (state_func_t) death_single;
856 			if (errno == EINTR)
857 				continue;
858 			warning("wait for %s on %s failed: %m; going to "
859 			    "single user mode", shell, script);
860 			return (state_func_t) single_user;
861 		}
862 		if (wpid == pid && WIFSTOPPED(status)) {
863 			warning("init: %s on %s stopped, restarting\n",
864 			    shell, script);
865 			kill(pid, SIGCONT);
866 			wpid = -1;
867 		}
868 	} while (wpid != pid);
869 
870 	if (WIFSIGNALED(status) && WTERMSIG(status) == SIGTERM &&
871 	    requested_transition == catatonia) {
872 		/* /etc/rc executed /sbin/reboot; wait for the end quietly */
873 		sigset_t s;
874 
875 		sigfillset(&s);
876 		for (;;)
877 			sigsuspend(&s);
878 	}
879 
880 	if (!WIFEXITED(status)) {
881 		warning("%s on %s terminated abnormally, going to single "
882 		    "user mode", shell, script);
883 		return (state_func_t) single_user;
884 	}
885 
886 	if (WEXITSTATUS(status))
887 		return (state_func_t) single_user;
888 
889 	return (state_func_t) 0;
890 }
891 
892 /*
893  * Open the session database.
894  *
895  * NB: We could pass in the size here; is it necessary?
896  */
897 static int
898 start_session_db(void)
899 {
900 	if (session_db && (*session_db->close)(session_db))
901 		emergency("session database close: %s", strerror(errno));
902 	if ((session_db = dbopen(NULL, O_RDWR, 0, DB_HASH, NULL)) == 0) {
903 		emergency("session database open: %s", strerror(errno));
904 		return (1);
905 	}
906 	return (0);
907 
908 }
909 
910 /*
911  * Add a new login session.
912  */
913 static void
914 add_session(session_t *sp)
915 {
916 	DBT key;
917 	DBT data;
918 
919 	key.data = &sp->se_process;
920 	key.size = sizeof sp->se_process;
921 	data.data = &sp;
922 	data.size = sizeof sp;
923 
924 	if ((*session_db->put)(session_db, &key, &data, 0))
925 		emergency("insert %d: %s", sp->se_process, strerror(errno));
926 }
927 
928 /*
929  * Delete an old login session.
930  */
931 static void
932 del_session(session_t *sp)
933 {
934 	DBT key;
935 
936 	key.data = &sp->se_process;
937 	key.size = sizeof sp->se_process;
938 
939 	if ((*session_db->del)(session_db, &key, 0))
940 		emergency("delete %d: %s", sp->se_process, strerror(errno));
941 }
942 
943 /*
944  * Look up a login session by pid.
945  */
946 static session_t *
947 find_session(pid_t pid)
948 {
949 	DBT key;
950 	DBT data;
951 	session_t *ret;
952 
953 	key.data = &pid;
954 	key.size = sizeof pid;
955 	if ((*session_db->get)(session_db, &key, &data, 0) != 0)
956 		return 0;
957 	bcopy(data.data, (char *)&ret, sizeof(ret));
958 	return ret;
959 }
960 
961 /*
962  * Construct an argument vector from a command line.
963  */
964 static char **
965 construct_argv(char *command)
966 {
967 	int argc = 0;
968 	char **argv = (char **) malloc(((strlen(command) + 1) / 2 + 1)
969 						* sizeof (char *));
970 
971 	if ((argv[argc++] = strk(command)) == 0) {
972 		free(argv);
973 		return (NULL);
974 	}
975 	while ((argv[argc++] = strk((char *) 0)) != NULL)
976 		continue;
977 	return argv;
978 }
979 
980 /*
981  * Deallocate a session descriptor.
982  */
983 static void
984 free_session(session_t *sp)
985 {
986 	free(sp->se_device);
987 	if (sp->se_getty) {
988 		free(sp->se_getty);
989 		free(sp->se_getty_argv_space);
990 		free(sp->se_getty_argv);
991 	}
992 	if (sp->se_window) {
993 		free(sp->se_window);
994 		free(sp->se_window_argv_space);
995 		free(sp->se_window_argv);
996 	}
997 	if (sp->se_type)
998 		free(sp->se_type);
999 	free(sp);
1000 }
1001 
1002 /*
1003  * Allocate a new session descriptor.
1004  * Mark it SE_PRESENT.
1005  */
1006 static session_t *
1007 new_session(session_t *sprev, struct ttyent *typ)
1008 {
1009 	session_t *sp;
1010 	int fd;
1011 
1012 	if ((typ->ty_status & TTY_ON) == 0 ||
1013 	    typ->ty_name == 0 ||
1014 	    typ->ty_getty == 0)
1015 		return 0;
1016 
1017 	sp = (session_t *) calloc(1, sizeof (session_t));
1018 
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 	session_t *sp, *snext;
1109 	struct ttyent *typ;
1110 
1111 	/*
1112 	 * Destroy any previous session state.
1113 	 * There shouldn't be any, but just in case...
1114 	 */
1115 	for (sp = sessions; sp; sp = snext) {
1116 		snext = sp->se_next;
1117 		free_session(sp);
1118 	}
1119 	sessions = 0;
1120 	if (start_session_db())
1121 		return (state_func_t) single_user;
1122 
1123 	/*
1124 	 * Allocate a session entry for each active port.
1125 	 * Note that sp starts at 0.
1126 	 */
1127 	while ((typ = getttyent()) != NULL)
1128 		if ((snext = new_session(sp, typ)) != NULL)
1129 			sp = snext;
1130 
1131 	endttyent();
1132 
1133 	return (state_func_t) multi_user;
1134 }
1135 
1136 /*
1137  * Start a window system running.
1138  */
1139 static void
1140 start_window_system(session_t *sp)
1141 {
1142 	pid_t pid;
1143 	sigset_t mask;
1144 	char term[64], *env[2];
1145 	int status;
1146 
1147 	if ((pid = fork()) == -1) {
1148 		emergency("can't fork for window system on port %s: %m",
1149 		    sp->se_device);
1150 		/* hope that getty fails and we can try again */
1151 		return;
1152 	}
1153 	if (pid) {
1154 		waitpid(-1, &status, 0);
1155 		return;
1156 	}
1157 
1158 	/* reparent window process to the init to not make a zombie on exit */
1159 	if ((pid = fork()) == -1) {
1160 		emergency("can't fork for window system on port %s: %m",
1161 		    sp->se_device);
1162 		_exit(1);
1163 	}
1164 	if (pid)
1165 		_exit(0);
1166 
1167 	sigemptyset(&mask);
1168 	sigprocmask(SIG_SETMASK, &mask, (sigset_t *) 0);
1169 
1170 	if (setsid() < 0)
1171 		emergency("setsid failed (window) %m");
1172 
1173 #ifdef LOGIN_CAP
1174 	setprocresources(RESOURCE_WINDOW);
1175 #endif
1176 	if (sp->se_type) {
1177 		/* Don't use malloc after fork */
1178 		strcpy(term, "TERM=");
1179 		strncat(term, sp->se_type, sizeof(term) - 6);
1180 		env[0] = term;
1181 		env[1] = 0;
1182 	}
1183 	else
1184 		env[0] = 0;
1185 	execve(sp->se_window_argv[0], sp->se_window_argv, env);
1186 	stall("can't exec window system '%s' for port %s: %m",
1187 		sp->se_window_argv[0], sp->se_device);
1188 	_exit(1);
1189 }
1190 
1191 /*
1192  * Start a login session running.
1193  */
1194 static pid_t
1195 start_getty(session_t *sp)
1196 {
1197 	pid_t pid;
1198 	sigset_t mask;
1199 	time_t current_time = time((time_t *) 0);
1200 	int too_quick = 0;
1201 	char term[64], *env[2];
1202 
1203 	if (current_time >= sp->se_started &&
1204 	    current_time - sp->se_started < GETTY_SPACING) {
1205 		if (++sp->se_nspace > GETTY_NSPACE) {
1206 			sp->se_nspace = 0;
1207 			too_quick = 1;
1208 		}
1209 	} else
1210 		sp->se_nspace = 0;
1211 
1212 	/*
1213 	 * fork(), not vfork() -- we can't afford to block.
1214 	 */
1215 	if ((pid = fork()) == -1) {
1216 		emergency("can't fork for getty on port %s: %m", sp->se_device);
1217 		return -1;
1218 	}
1219 
1220 	if (pid)
1221 		return pid;
1222 
1223 	if (too_quick) {
1224 		warning("getty repeating too quickly on port %s, sleeping %d secs",
1225 		    sp->se_device, GETTY_SLEEP);
1226 		sleep((unsigned) GETTY_SLEEP);
1227 	}
1228 
1229 	if (sp->se_window) {
1230 		start_window_system(sp);
1231 		sleep(WINDOW_WAIT);
1232 	}
1233 
1234 	sigemptyset(&mask);
1235 	sigprocmask(SIG_SETMASK, &mask, (sigset_t *) 0);
1236 
1237 #ifdef LOGIN_CAP
1238 	setprocresources(RESOURCE_GETTY);
1239 #endif
1240 	if (sp->se_type) {
1241 		/* Don't use malloc after fork */
1242 		strcpy(term, "TERM=");
1243 		strncat(term, sp->se_type, sizeof(term) - 6);
1244 		env[0] = term;
1245 		env[1] = 0;
1246 	} else
1247 		env[0] = 0;
1248 	execve(sp->se_getty_argv[0], sp->se_getty_argv, env);
1249 	stall("can't exec getty '%s' for port %s: %m",
1250 		sp->se_getty_argv[0], sp->se_device);
1251 	_exit(1);
1252 }
1253 
1254 /*
1255  * Collect exit status for a child.
1256  * If an exiting login, start a new login running.
1257  */
1258 static void
1259 collect_child(pid_t pid)
1260 {
1261 	session_t *sp, *sprev, *snext;
1262 
1263 	if (! sessions)
1264 		return;
1265 
1266 	if (! (sp = find_session(pid)))
1267 		return;
1268 
1269 	del_session(sp);
1270 	sp->se_process = 0;
1271 
1272 	if (sp->se_flags & SE_SHUTDOWN) {
1273 		if ((sprev = sp->se_prev) != NULL)
1274 			sprev->se_next = sp->se_next;
1275 		else
1276 			sessions = sp->se_next;
1277 		if ((snext = sp->se_next) != NULL)
1278 			snext->se_prev = sp->se_prev;
1279 		free_session(sp);
1280 		return;
1281 	}
1282 
1283 	if ((pid = start_getty(sp)) == -1) {
1284 		/* serious trouble */
1285 		requested_transition = clean_ttys;
1286 		return;
1287 	}
1288 
1289 	sp->se_process = pid;
1290 	sp->se_started = time((time_t *) 0);
1291 	add_session(sp);
1292 }
1293 
1294 /*
1295  * Catch a signal and request a state transition.
1296  */
1297 static void
1298 transition_handler(int sig)
1299 {
1300 
1301 	switch (sig) {
1302 	case SIGHUP:
1303 		if (current_state == read_ttys || current_state == multi_user ||
1304 		    current_state == clean_ttys || current_state == catatonia)
1305 			requested_transition = clean_ttys;
1306 		break;
1307 	case SIGUSR2:
1308 		howto = RB_POWEROFF;
1309 	case SIGUSR1:
1310 		howto |= RB_HALT;
1311 	case SIGINT:
1312 		Reboot = TRUE;
1313 	case SIGTERM:
1314 		if (current_state == read_ttys || current_state == multi_user ||
1315 		    current_state == clean_ttys || current_state == catatonia)
1316 			requested_transition = death;
1317 		else
1318 			requested_transition = death_single;
1319 		break;
1320 	case SIGTSTP:
1321 		if (current_state == runcom || current_state == read_ttys ||
1322 		    current_state == clean_ttys ||
1323 		    current_state == multi_user || current_state == catatonia)
1324 			requested_transition = catatonia;
1325 		break;
1326 	default:
1327 		requested_transition = 0;
1328 		break;
1329 	}
1330 }
1331 
1332 /*
1333  * Take the system multiuser.
1334  */
1335 static state_func_t
1336 multi_user(void)
1337 {
1338 	pid_t pid;
1339 	session_t *sp;
1340 
1341 	requested_transition = 0;
1342 
1343 	/*
1344 	 * If the administrator has not set the security level to -1
1345 	 * to indicate that the kernel should not run multiuser in secure
1346 	 * mode, and the run script has not set a higher level of security
1347 	 * than level 1, then put the kernel into secure mode.
1348 	 */
1349 	if (getsecuritylevel() == 0)
1350 		setsecuritylevel(1);
1351 
1352 	for (sp = sessions; sp; sp = sp->se_next) {
1353 		if (sp->se_process)
1354 			continue;
1355 		if ((pid = start_getty(sp)) == -1) {
1356 			/* serious trouble */
1357 			requested_transition = clean_ttys;
1358 			break;
1359 		}
1360 		sp->se_process = pid;
1361 		sp->se_started = time((time_t *) 0);
1362 		add_session(sp);
1363 	}
1364 
1365 	while (!requested_transition)
1366 		if ((pid = waitpid(-1, (int *) 0, 0)) != -1)
1367 			collect_child(pid);
1368 
1369 	return (state_func_t) requested_transition;
1370 }
1371 
1372 /*
1373  * This is an (n*2)+(n^2) algorithm.  We hope it isn't run often...
1374  */
1375 static state_func_t
1376 clean_ttys(void)
1377 {
1378 	session_t *sp, *sprev;
1379 	struct ttyent *typ;
1380 	int devlen;
1381 	char *old_getty, *old_window, *old_type;
1382 
1383 	/*
1384 	 * mark all sessions for death, (!SE_PRESENT)
1385 	 * as we find or create new ones they'll be marked as keepers,
1386 	 * we'll later nuke all the ones not found in /etc/ttys
1387 	 */
1388 	for (sp = sessions; sp != NULL; sp = sp->se_next)
1389 		sp->se_flags &= ~SE_PRESENT;
1390 
1391 	devlen = sizeof(_PATH_DEV) - 1;
1392 	while ((typ = getttyent()) != NULL) {
1393 		for (sprev = 0, sp = sessions; sp; sprev = sp, sp = sp->se_next)
1394 			if (strcmp(typ->ty_name, sp->se_device + devlen) == 0)
1395 				break;
1396 
1397 		if (sp) {
1398 			/* we want this one to live */
1399 			sp->se_flags |= SE_PRESENT;
1400 			if ((typ->ty_status & TTY_ON) == 0 ||
1401 			    typ->ty_getty == 0) {
1402 				sp->se_flags |= SE_SHUTDOWN;
1403 				kill(sp->se_process, SIGHUP);
1404 				continue;
1405 			}
1406 			sp->se_flags &= ~SE_SHUTDOWN;
1407 			old_getty = sp->se_getty ? strdup(sp->se_getty) : 0;
1408 			old_window = sp->se_window ? strdup(sp->se_window) : 0;
1409 			old_type = sp->se_type ? strdup(sp->se_type) : 0;
1410 			if (setupargv(sp, typ) == 0) {
1411 				warning("can't parse getty for port %s",
1412 					sp->se_device);
1413 				sp->se_flags |= SE_SHUTDOWN;
1414 				kill(sp->se_process, SIGHUP);
1415 			}
1416 			else if (   !old_getty
1417 				 || (!old_type && sp->se_type)
1418 				 || (old_type && !sp->se_type)
1419 				 || (!old_window && sp->se_window)
1420 				 || (old_window && !sp->se_window)
1421 				 || (strcmp(old_getty, sp->se_getty) != 0)
1422 				 || (old_window && strcmp(old_window, sp->se_window) != 0)
1423 				 || (old_type && strcmp(old_type, sp->se_type) != 0)
1424 				) {
1425 				/* Don't set SE_SHUTDOWN here */
1426 				sp->se_nspace = 0;
1427 				sp->se_started = 0;
1428 				kill(sp->se_process, SIGHUP);
1429 			}
1430 			if (old_getty)
1431 				free(old_getty);
1432 			if (old_window)
1433 				free(old_window);
1434 			if (old_type)
1435 				free(old_type);
1436 			continue;
1437 		}
1438 
1439 		new_session(sprev, typ);
1440 	}
1441 
1442 	endttyent();
1443 
1444 	/*
1445 	 * sweep through and kill all deleted sessions
1446 	 * ones who's /etc/ttys line was deleted (SE_PRESENT unset)
1447 	 */
1448 	for (sp = sessions; sp != NULL; sp = sp->se_next) {
1449 		if ((sp->se_flags & SE_PRESENT) == 0) {
1450 			sp->se_flags |= SE_SHUTDOWN;
1451 			kill(sp->se_process, SIGHUP);
1452 		}
1453 	}
1454 
1455 	return (state_func_t) multi_user;
1456 }
1457 
1458 /*
1459  * Block further logins.
1460  */
1461 static state_func_t
1462 catatonia(void)
1463 {
1464 	session_t *sp;
1465 
1466 	for (sp = sessions; sp; sp = sp->se_next)
1467 		sp->se_flags |= SE_SHUTDOWN;
1468 
1469 	return (state_func_t) multi_user;
1470 }
1471 
1472 /*
1473  * Note SIGALRM.
1474  */
1475 static void
1476 alrm_handler(int sig)
1477 {
1478 
1479 	(void)sig;
1480 	clang = 1;
1481 }
1482 
1483 /*
1484  * Bring the system down to single user.
1485  */
1486 static state_func_t
1487 death(void)
1488 {
1489 	session_t *sp;
1490 
1491 	/*
1492 	 * Also revoke the TTY here.  Because runshutdown() may reopen
1493 	 * the TTY whose getty we're killing here, there is no guarantee
1494 	 * runshutdown() will perform the initial open() call, causing
1495 	 * the terminal attributes to be misconfigured.
1496 	 */
1497 	for (sp = sessions; sp; sp = sp->se_next) {
1498 		sp->se_flags |= SE_SHUTDOWN;
1499 		kill(sp->se_process, SIGHUP);
1500 		revoke(sp->se_device);
1501 	}
1502 
1503 	/* Try to run the rc.shutdown script within a period of time */
1504 	runshutdown();
1505 
1506 	return (state_func_t) death_single;
1507 }
1508 
1509 /*
1510  * Do what is necessary to reinitialize single user mode or reboot
1511  * from an incomplete state.
1512  */
1513 static state_func_t
1514 death_single(void)
1515 {
1516 	int i;
1517 	pid_t pid;
1518 	static const int death_sigs[2] = { SIGTERM, SIGKILL };
1519 
1520 	revoke(_PATH_CONSOLE);
1521 
1522 	for (i = 0; i < 2; ++i) {
1523 		if (kill(-1, death_sigs[i]) == -1 && errno == ESRCH)
1524 			return (state_func_t) single_user;
1525 
1526 		clang = 0;
1527 		alarm(DEATH_WATCH);
1528 		do
1529 			if ((pid = waitpid(-1, (int *)0, 0)) != -1)
1530 				collect_child(pid);
1531 		while (clang == 0 && errno != ECHILD);
1532 
1533 		if (errno == ECHILD)
1534 			return (state_func_t) single_user;
1535 	}
1536 
1537 	warning("some processes would not die; ps axl advised");
1538 
1539 	return (state_func_t) single_user;
1540 }
1541 
1542 /*
1543  * Run the system shutdown script.
1544  *
1545  * Exit codes:      XXX I should document more
1546  * -2       shutdown script terminated abnormally
1547  * -1       fatal error - can't run script
1548  * 0        good.
1549  * >0       some error (exit code)
1550  */
1551 static int
1552 runshutdown(void)
1553 {
1554 	pid_t pid, wpid;
1555 	int status;
1556 	int shutdowntimeout;
1557 	size_t len;
1558 	char *argv[4];
1559 	const char *shell;
1560 	struct sigaction sa;
1561 	struct stat sb;
1562 
1563 	/*
1564 	 * rc.shutdown is optional, so to prevent any unnecessary
1565 	 * complaints from the shell we simply don't run it if the
1566 	 * file does not exist. If the stat() here fails for other
1567 	 * reasons, we'll let the shell complain.
1568 	 */
1569 	if (stat(_PATH_RUNDOWN, &sb) == -1 && errno == ENOENT)
1570 		return 0;
1571 
1572 	shell = get_shell();
1573 
1574 	if ((pid = fork()) == 0) {
1575 		sigemptyset(&sa.sa_mask);
1576 		sa.sa_flags = 0;
1577 		sa.sa_handler = SIG_IGN;
1578 		sigaction(SIGTSTP, &sa, (struct sigaction *)0);
1579 		sigaction(SIGHUP, &sa, (struct sigaction *)0);
1580 
1581 		open_console();
1582 
1583 		char _sh[]	= "sh";
1584 		char _reboot[]	= "reboot";
1585 		char _single[]	= "single";
1586 		char _path_rundown[] = _PATH_RUNDOWN;
1587 
1588 		argv[0] = _sh;
1589 		argv[1] = _path_rundown;
1590 		argv[2] = Reboot ? _reboot : _single;
1591 		argv[3] = 0;
1592 
1593 		sigprocmask(SIG_SETMASK, &sa.sa_mask, (sigset_t *) 0);
1594 
1595 #ifdef LOGIN_CAP
1596 		setprocresources(RESOURCE_RC);
1597 #endif
1598 		execv(shell, argv);
1599 		warning("can't exec %s for %s: %m", shell, _PATH_RUNDOWN);
1600 		_exit(1);	/* force single user mode */
1601 	}
1602 
1603 	if (pid == -1) {
1604 		emergency("can't fork for %s on %s: %m", shell, _PATH_RUNDOWN);
1605 		while (waitpid(-1, (int *) 0, WNOHANG) > 0)
1606 			continue;
1607 		sleep(STALL_TIMEOUT);
1608 		return -1;
1609 	}
1610 
1611 	len = sizeof(shutdowntimeout);
1612 	if (sysctlbyname("kern.init_shutdown_timeout", &shutdowntimeout, &len,
1613 	    NULL, 0) == -1 || shutdowntimeout < 2)
1614 		shutdowntimeout = DEATH_SCRIPT;
1615 	alarm(shutdowntimeout);
1616 	clang = 0;
1617 	/*
1618 	 * Copied from single_user().  This is a bit paranoid.
1619 	 * Use the same ALRM handler.
1620 	 */
1621 	do {
1622 		if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1)
1623 			collect_child(wpid);
1624 		if (clang == 1) {
1625 			/* we were waiting for the sub-shell */
1626 			kill(wpid, SIGTERM);
1627 			warning("timeout expired for %s on %s: %m; going to "
1628 			    "single user mode", shell, _PATH_RUNDOWN);
1629 			return -1;
1630 		}
1631 		if (wpid == -1) {
1632 			if (errno == EINTR)
1633 				continue;
1634 			warning("wait for %s on %s failed: %m; going to "
1635 			    "single user mode", shell, _PATH_RUNDOWN);
1636 			return -1;
1637 		}
1638 		if (wpid == pid && WIFSTOPPED(status)) {
1639 			warning("init: %s on %s stopped, restarting\n",
1640 				shell, _PATH_RUNDOWN);
1641 			kill(pid, SIGCONT);
1642 			wpid = -1;
1643 		}
1644 	} while (wpid != pid && !clang);
1645 
1646 	/* Turn off the alarm */
1647 	alarm(0);
1648 
1649 	if (WIFSIGNALED(status) && WTERMSIG(status) == SIGTERM &&
1650 	    requested_transition == catatonia) {
1651 		/*
1652 		 * /etc/rc.shutdown executed /sbin/reboot;
1653 		 * wait for the end quietly
1654 		 */
1655 		sigset_t s;
1656 
1657 		sigfillset(&s);
1658 		for (;;)
1659 			sigsuspend(&s);
1660 	}
1661 
1662 	if (!WIFEXITED(status)) {
1663 		warning("%s on %s terminated abnormally, going to "
1664 		    "single user mode", shell, _PATH_RUNDOWN);
1665 		return -2;
1666 	}
1667 
1668 	if ((status = WEXITSTATUS(status)) != 0)
1669 		warning("%s returned status %d", _PATH_RUNDOWN, status);
1670 
1671 	return status;
1672 }
1673 
1674 static char *
1675 strk(char *p)
1676 {
1677 	static char *t;
1678 	char *q;
1679 	int c;
1680 
1681 	if (p)
1682 		t = p;
1683 	if (!t)
1684 		return 0;
1685 
1686 	c = *t;
1687 	while (c == ' ' || c == '\t' )
1688 		c = *++t;
1689 	if (!c) {
1690 		t = 0;
1691 		return 0;
1692 	}
1693 	q = t;
1694 	if (c == '\'') {
1695 		c = *++t;
1696 		q = t;
1697 		while (c && c != '\'')
1698 			c = *++t;
1699 		if (!c)  /* unterminated string */
1700 			q = t = 0;
1701 		else
1702 			*t++ = 0;
1703 	} else {
1704 		while (c && c != ' ' && c != '\t' )
1705 			c = *++t;
1706 		*t++ = 0;
1707 		if (!c)
1708 			t = 0;
1709 	}
1710 	return q;
1711 }
1712 
1713 #ifdef LOGIN_CAP
1714 static void
1715 setprocresources(const char *cname)
1716 {
1717 	login_cap_t *lc;
1718 	if ((lc = login_getclassbyname(cname, NULL)) != NULL) {
1719 		setusercontext(lc, (struct passwd*)NULL, 0,
1720 		    LOGIN_SETPRIORITY | LOGIN_SETRESOURCES |
1721 		    LOGIN_SETLOGINCLASS | LOGIN_SETCPUMASK);
1722 		login_close(lc);
1723 	}
1724 }
1725 #endif
1726