xref: /freebsd/sbin/init/init.c (revision 39beb93c3f8bdbf72a61fda42300b5ebed7390c8)
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 
125 static state_func_t run_script(const char *);
126 
127 enum { AUTOBOOT, FASTBOOT } runcom_mode = AUTOBOOT;
128 #define FALSE	0
129 #define TRUE	1
130 
131 int Reboot = FALSE;
132 int howto = RB_AUTOBOOT;
133 
134 int devfs;
135 
136 static void transition(state_t);
137 static state_t requested_transition;
138 
139 static void setctty(const char *);
140 static const char *get_shell(void);
141 static void write_stderr(const char *message);
142 
143 typedef struct init_session {
144 	int	se_index;		/* index of entry in ttys file */
145 	pid_t	se_process;		/* controlling process */
146 	time_t	se_started;		/* used to avoid thrashing */
147 	int	se_flags;		/* status of session */
148 #define	SE_SHUTDOWN	0x1		/* session won't be restarted */
149 #define	SE_PRESENT	0x2		/* session is in /etc/ttys */
150 	int     se_nspace;              /* spacing count */
151 	char	*se_device;		/* filename of port */
152 	char	*se_getty;		/* what to run on that port */
153 	char    *se_getty_argv_space;   /* pre-parsed argument array space */
154 	char	**se_getty_argv;	/* pre-parsed argument array */
155 	char	*se_window;		/* window system (started only once) */
156 	char    *se_window_argv_space;  /* pre-parsed argument array space */
157 	char	**se_window_argv;	/* pre-parsed argument array */
158 	char    *se_type;               /* default terminal type */
159 	struct	init_session *se_prev;
160 	struct	init_session *se_next;
161 } session_t;
162 
163 static void free_session(session_t *);
164 static session_t *new_session(session_t *, int, struct ttyent *);
165 static session_t *sessions;
166 
167 static char **construct_argv(char *);
168 static void start_window_system(session_t *);
169 static void collect_child(pid_t);
170 static pid_t start_getty(session_t *);
171 static void transition_handler(int);
172 static void alrm_handler(int);
173 static void setsecuritylevel(int);
174 static int getsecuritylevel(void);
175 static int setupargv(session_t *, struct ttyent *);
176 #ifdef LOGIN_CAP
177 static void setprocresources(const char *);
178 #endif
179 static int clang;
180 
181 static void clear_session_logs(session_t *);
182 
183 static int start_session_db(void);
184 static void add_session(session_t *);
185 static void del_session(session_t *);
186 static session_t *find_session(pid_t);
187 static DB *session_db;
188 
189 /*
190  * The mother of all processes.
191  */
192 int
193 main(int argc, char *argv[])
194 {
195 	state_t initial_transition = runcom;
196 	char kenv_value[PATH_MAX];
197 	int c;
198 	struct sigaction sa;
199 	sigset_t mask;
200 
201 	/* Dispose of random users. */
202 	if (getuid() != 0)
203 		errx(1, "%s", strerror(EPERM));
204 
205 	/* System V users like to reexec init. */
206 	if (getpid() != 1) {
207 #ifdef COMPAT_SYSV_INIT
208 		/* So give them what they want */
209 		if (argc > 1) {
210 			if (strlen(argv[1]) == 1) {
211 				char runlevel = *argv[1];
212 				int sig;
213 
214 				switch (runlevel) {
215 				case '0': /* halt + poweroff */
216 					sig = SIGUSR2;
217 					break;
218 				case '1': /* single-user */
219 					sig = SIGTERM;
220 					break;
221 				case '6': /* reboot */
222 					sig = SIGINT;
223 					break;
224 				case 'c': /* block further logins */
225 					sig = SIGTSTP;
226 					break;
227 				case 'q': /* rescan /etc/ttys */
228 					sig = SIGHUP;
229 					break;
230 				default:
231 					goto invalid;
232 				}
233 				kill(1, sig);
234 				_exit(0);
235 			} else
236 invalid:
237 				errx(1, "invalid run-level ``%s''", argv[1]);
238 		} else
239 #endif
240 			errx(1, "already running");
241 	}
242 	/*
243 	 * Note that this does NOT open a file...
244 	 * Does 'init' deserve its own facility number?
245 	 */
246 	openlog("init", LOG_CONS|LOG_ODELAY, LOG_AUTH);
247 
248 	/*
249 	 * Create an initial session.
250 	 */
251 	if (setsid() < 0)
252 		warning("initial setsid() failed: %m");
253 
254 	/*
255 	 * Establish an initial user so that programs running
256 	 * single user do not freak out and die (like passwd).
257 	 */
258 	if (setlogin("root") < 0)
259 		warning("setlogin() failed: %m");
260 
261 	/*
262 	 * This code assumes that we always get arguments through flags,
263 	 * never through bits set in some random machine register.
264 	 */
265 	while ((c = getopt(argc, argv, "dsf")) != -1)
266 		switch (c) {
267 		case 'd':
268 			devfs = 1;
269 			break;
270 		case 's':
271 			initial_transition = single_user;
272 			break;
273 		case 'f':
274 			runcom_mode = FASTBOOT;
275 			break;
276 		default:
277 			warning("unrecognized flag '-%c'", c);
278 			break;
279 		}
280 
281 	if (optind != argc)
282 		warning("ignoring excess arguments");
283 
284 	/*
285 	 * We catch or block signals rather than ignore them,
286 	 * so that they get reset on exec.
287 	 */
288 	handle(badsys, SIGSYS, 0);
289 	handle(disaster, SIGABRT, SIGFPE, SIGILL, SIGSEGV, SIGBUS, SIGXCPU,
290 	    SIGXFSZ, 0);
291 	handle(transition_handler, SIGHUP, SIGINT, SIGTERM, SIGTSTP, SIGUSR1,
292 	    SIGUSR2, 0);
293 	handle(alrm_handler, SIGALRM, 0);
294 	sigfillset(&mask);
295 	delset(&mask, SIGABRT, SIGFPE, SIGILL, SIGSEGV, SIGBUS, SIGSYS,
296 	    SIGXCPU, SIGXFSZ, SIGHUP, SIGINT, SIGTERM, SIGTSTP, SIGALRM,
297 	    SIGUSR1, SIGUSR2, 0);
298 	sigprocmask(SIG_SETMASK, &mask, (sigset_t *) 0);
299 	sigemptyset(&sa.sa_mask);
300 	sa.sa_flags = 0;
301 	sa.sa_handler = SIG_IGN;
302 	sigaction(SIGTTIN, &sa, (struct sigaction *)0);
303 	sigaction(SIGTTOU, &sa, (struct sigaction *)0);
304 
305 	/*
306 	 * Paranoia.
307 	 */
308 	close(0);
309 	close(1);
310 	close(2);
311 
312 	if (kenv(KENV_GET, "init_script", kenv_value, sizeof(kenv_value)) > 0) {
313 		state_func_t next_transition;
314 
315 		if ((next_transition = run_script(kenv_value)) != 0)
316 			initial_transition = (state_t) next_transition;
317 	}
318 
319 	if (kenv(KENV_GET, "init_chroot", kenv_value, sizeof(kenv_value)) > 0) {
320 		if (chdir(kenv_value) != 0 || chroot(".") != 0)
321 			warning("Can't chroot to %s: %m", kenv_value);
322 	}
323 
324 	/*
325 	 * Additional check if devfs needs to be mounted:
326 	 * If "/" and "/dev" have the same device number,
327 	 * then it hasn't been mounted yet.
328 	 */
329 	if (!devfs) {
330 		struct stat stst;
331 		dev_t root_devno;
332 
333 		stat("/", &stst);
334 		root_devno = stst.st_dev;
335 		if (stat("/dev", &stst) != 0)
336 			warning("Can't stat /dev: %m");
337 		else if (stst.st_dev == root_devno)
338 			devfs++;
339 	}
340 
341 	if (devfs) {
342 		struct iovec iov[4];
343 		char *s;
344 		int i;
345 
346 		char _fstype[]	= "fstype";
347 		char _devfs[]	= "devfs";
348 		char _fspath[]	= "fspath";
349 		char _path_dev[]= _PATH_DEV;
350 
351 		iov[0].iov_base = _fstype;
352 		iov[0].iov_len = sizeof(_fstype);
353 		iov[1].iov_base = _devfs;
354 		iov[1].iov_len = sizeof(_devfs);
355 		iov[2].iov_base = _fspath;
356 		iov[2].iov_len = sizeof(_fspath);
357 		/*
358 		 * Try to avoid the trailing slash in _PATH_DEV.
359 		 * Be *very* defensive.
360 		 */
361 		s = strdup(_PATH_DEV);
362 		if (s != NULL) {
363 			i = strlen(s);
364 			if (i > 0 && s[i - 1] == '/')
365 				s[i - 1] = '\0';
366 			iov[3].iov_base = s;
367 			iov[3].iov_len = strlen(s) + 1;
368 		} else {
369 			iov[3].iov_base = _path_dev;
370 			iov[3].iov_len = sizeof(_path_dev);
371 		}
372 		nmount(iov, 4, 0);
373 		if (s != NULL)
374 			free(s);
375 	}
376 
377 	/*
378 	 * Start the state machine.
379 	 */
380 	transition(initial_transition);
381 
382 	/*
383 	 * Should never reach here.
384 	 */
385 	return 1;
386 }
387 
388 /*
389  * Associate a function with a signal handler.
390  */
391 static void
392 handle(sig_t handler, ...)
393 {
394 	int sig;
395 	struct sigaction sa;
396 	sigset_t mask_everything;
397 	va_list ap;
398 	va_start(ap, handler);
399 
400 	sa.sa_handler = handler;
401 	sigfillset(&mask_everything);
402 
403 	while ((sig = va_arg(ap, int)) != 0) {
404 		sa.sa_mask = mask_everything;
405 		/* XXX SA_RESTART? */
406 		sa.sa_flags = sig == SIGCHLD ? SA_NOCLDSTOP : 0;
407 		sigaction(sig, &sa, (struct sigaction *) 0);
408 	}
409 	va_end(ap);
410 }
411 
412 /*
413  * Delete a set of signals from a mask.
414  */
415 static void
416 delset(sigset_t *maskp, ...)
417 {
418 	int sig;
419 	va_list ap;
420 	va_start(ap, maskp);
421 
422 	while ((sig = va_arg(ap, int)) != 0)
423 		sigdelset(maskp, sig);
424 	va_end(ap);
425 }
426 
427 /*
428  * Log a message and sleep for a while (to give someone an opportunity
429  * to read it and to save log or hardcopy output if the problem is chronic).
430  * NB: should send a message to the session logger to avoid blocking.
431  */
432 static void
433 stall(const char *message, ...)
434 {
435 	va_list ap;
436 	va_start(ap, message);
437 
438 	vsyslog(LOG_ALERT, message, ap);
439 	va_end(ap);
440 	sleep(STALL_TIMEOUT);
441 }
442 
443 /*
444  * Like stall(), but doesn't sleep.
445  * If cpp had variadic macros, the two functions could be #defines for another.
446  * NB: should send a message to the session logger to avoid blocking.
447  */
448 static void
449 warning(const char *message, ...)
450 {
451 	va_list ap;
452 	va_start(ap, message);
453 
454 	vsyslog(LOG_ALERT, message, ap);
455 	va_end(ap);
456 }
457 
458 /*
459  * Log an emergency message.
460  * NB: should send a message to the session logger to avoid blocking.
461  */
462 static void
463 emergency(const char *message, ...)
464 {
465 	va_list ap;
466 	va_start(ap, message);
467 
468 	vsyslog(LOG_EMERG, message, ap);
469 	va_end(ap);
470 }
471 
472 /*
473  * Catch a SIGSYS signal.
474  *
475  * These may arise if a system does not support sysctl.
476  * We tolerate up to 25 of these, then throw in the towel.
477  */
478 static void
479 badsys(int sig)
480 {
481 	static int badcount = 0;
482 
483 	if (badcount++ < 25)
484 		return;
485 	disaster(sig);
486 }
487 
488 /*
489  * Catch an unexpected signal.
490  */
491 static void
492 disaster(int sig)
493 {
494 
495 	emergency("fatal signal: %s",
496 	    (unsigned)sig < NSIG ? sys_siglist[sig] : "unknown signal");
497 
498 	sleep(STALL_TIMEOUT);
499 	_exit(sig);		/* reboot */
500 }
501 
502 /*
503  * Get the security level of the kernel.
504  */
505 static int
506 getsecuritylevel(void)
507 {
508 #ifdef KERN_SECURELVL
509 	int name[2], curlevel;
510 	size_t len;
511 
512 	name[0] = CTL_KERN;
513 	name[1] = KERN_SECURELVL;
514 	len = sizeof curlevel;
515 	if (sysctl(name, 2, &curlevel, &len, NULL, 0) == -1) {
516 		emergency("cannot get kernel security level: %s",
517 		    strerror(errno));
518 		return (-1);
519 	}
520 	return (curlevel);
521 #else
522 	return (-1);
523 #endif
524 }
525 
526 /*
527  * Set the security level of the kernel.
528  */
529 static void
530 setsecuritylevel(int newlevel)
531 {
532 #ifdef KERN_SECURELVL
533 	int name[2], curlevel;
534 
535 	curlevel = getsecuritylevel();
536 	if (newlevel == curlevel)
537 		return;
538 	name[0] = CTL_KERN;
539 	name[1] = KERN_SECURELVL;
540 	if (sysctl(name, 2, NULL, NULL, &newlevel, sizeof newlevel) == -1) {
541 		emergency(
542 		    "cannot change kernel security level from %d to %d: %s",
543 		    curlevel, newlevel, strerror(errno));
544 		return;
545 	}
546 #ifdef SECURE
547 	warning("kernel security level changed from %d to %d",
548 	    curlevel, newlevel);
549 #endif
550 #endif
551 }
552 
553 /*
554  * Change states in the finite state machine.
555  * The initial state is passed as an argument.
556  */
557 static void
558 transition(state_t s)
559 {
560 
561 	for (;;)
562 		s = (state_t) (*s)();
563 }
564 
565 /*
566  * Close out the accounting files for a login session.
567  * NB: should send a message to the session logger to avoid blocking.
568  */
569 static void
570 clear_session_logs(session_t *sp)
571 {
572 	char *line = sp->se_device + sizeof(_PATH_DEV) - 1;
573 
574 	if (logout(line))
575 		logwtmp(line, "", "");
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 	state_func_t next_transition;
779 
780 	if ((next_transition = run_script(_PATH_RUNCOM)) != 0)
781 		return next_transition;
782 
783 	runcom_mode = AUTOBOOT;		/* the default */
784 	/* NB: should send a message to the session logger to avoid blocking. */
785 	logwtmp("~", "reboot", "");
786 	return (state_func_t) read_ttys;
787 }
788 
789 /*
790  * Run a shell script.
791  * Returns 0 on success, otherwise the next transition to enter:
792  *  - single_user if fork/execv/waitpid failed, or if the script
793  *    terminated with a signal or exit code != 0.
794  *  - death if a SIGTERM was delivered to init(8).
795  */
796 static state_func_t
797 run_script(const char *script)
798 {
799 	pid_t pid, wpid;
800 	int status;
801 	char *argv[4];
802 	const char *shell;
803 	struct sigaction sa;
804 
805 	shell = get_shell();
806 
807 	if ((pid = fork()) == 0) {
808 		sigemptyset(&sa.sa_mask);
809 		sa.sa_flags = 0;
810 		sa.sa_handler = SIG_IGN;
811 		sigaction(SIGTSTP, &sa, (struct sigaction *)0);
812 		sigaction(SIGHUP, &sa, (struct sigaction *)0);
813 
814 		setctty(_PATH_CONSOLE);
815 
816 		char _sh[]	 	= "sh";
817 		char _autoboot[]	= "autoboot";
818 
819 		argv[0] = _sh;
820 		argv[1] = __DECONST(char *, script);
821 		argv[2] = runcom_mode == AUTOBOOT ? _autoboot : 0;
822 		argv[3] = 0;
823 
824 		sigprocmask(SIG_SETMASK, &sa.sa_mask, (sigset_t *) 0);
825 
826 #ifdef LOGIN_CAP
827 		setprocresources(RESOURCE_RC);
828 #endif
829 		execv(shell, argv);
830 		stall("can't exec %s for %s: %m", shell, script);
831 		_exit(1);	/* force single user mode */
832 	}
833 
834 	if (pid == -1) {
835 		emergency("can't fork for %s on %s: %m", shell, script);
836 		while (waitpid(-1, (int *) 0, WNOHANG) > 0)
837 			continue;
838 		sleep(STALL_TIMEOUT);
839 		return (state_func_t) single_user;
840 	}
841 
842 	/*
843 	 * Copied from single_user().  This is a bit paranoid.
844 	 */
845 	requested_transition = 0;
846 	do {
847 		if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1)
848 			collect_child(wpid);
849 		if (wpid == -1) {
850 			if (requested_transition == death)
851 				return (state_func_t) death;
852 			if (errno == EINTR)
853 				continue;
854 			warning("wait for %s on %s failed: %m; going to "
855 			    "single user mode", shell, script);
856 			return (state_func_t) single_user;
857 		}
858 		if (wpid == pid && WIFSTOPPED(status)) {
859 			warning("init: %s on %s stopped, restarting\n",
860 			    shell, script);
861 			kill(pid, SIGCONT);
862 			wpid = -1;
863 		}
864 	} while (wpid != pid);
865 
866 	if (WIFSIGNALED(status) && WTERMSIG(status) == SIGTERM &&
867 	    requested_transition == catatonia) {
868 		/* /etc/rc executed /sbin/reboot; wait for the end quietly */
869 		sigset_t s;
870 
871 		sigfillset(&s);
872 		for (;;)
873 			sigsuspend(&s);
874 	}
875 
876 	if (!WIFEXITED(status)) {
877 		warning("%s on %s terminated abnormally, going to single "
878 		    "user mode", shell, script);
879 		return (state_func_t) single_user;
880 	}
881 
882 	if (WEXITSTATUS(status))
883 		return (state_func_t) single_user;
884 
885 	return (state_func_t) 0;
886 }
887 
888 /*
889  * Open the session database.
890  *
891  * NB: We could pass in the size here; is it necessary?
892  */
893 static int
894 start_session_db(void)
895 {
896 	if (session_db && (*session_db->close)(session_db))
897 		emergency("session database close: %s", strerror(errno));
898 	if ((session_db = dbopen(NULL, O_RDWR, 0, DB_HASH, NULL)) == 0) {
899 		emergency("session database open: %s", strerror(errno));
900 		return (1);
901 	}
902 	return (0);
903 
904 }
905 
906 /*
907  * Add a new login session.
908  */
909 static void
910 add_session(session_t *sp)
911 {
912 	DBT key;
913 	DBT data;
914 
915 	key.data = &sp->se_process;
916 	key.size = sizeof sp->se_process;
917 	data.data = &sp;
918 	data.size = sizeof sp;
919 
920 	if ((*session_db->put)(session_db, &key, &data, 0))
921 		emergency("insert %d: %s", sp->se_process, strerror(errno));
922 }
923 
924 /*
925  * Delete an old login session.
926  */
927 static void
928 del_session(session_t *sp)
929 {
930 	DBT key;
931 
932 	key.data = &sp->se_process;
933 	key.size = sizeof sp->se_process;
934 
935 	if ((*session_db->del)(session_db, &key, 0))
936 		emergency("delete %d: %s", sp->se_process, strerror(errno));
937 }
938 
939 /*
940  * Look up a login session by pid.
941  */
942 static session_t *
943 find_session(pid_t pid)
944 {
945 	DBT key;
946 	DBT data;
947 	session_t *ret;
948 
949 	key.data = &pid;
950 	key.size = sizeof pid;
951 	if ((*session_db->get)(session_db, &key, &data, 0) != 0)
952 		return 0;
953 	bcopy(data.data, (char *)&ret, sizeof(ret));
954 	return ret;
955 }
956 
957 /*
958  * Construct an argument vector from a command line.
959  */
960 static char **
961 construct_argv(char *command)
962 {
963 	int argc = 0;
964 	char **argv = (char **) malloc(((strlen(command) + 1) / 2 + 1)
965 						* sizeof (char *));
966 
967 	if ((argv[argc++] = strk(command)) == 0) {
968 		free(argv);
969 		return (NULL);
970 	}
971 	while ((argv[argc++] = strk((char *) 0)) != NULL)
972 		continue;
973 	return argv;
974 }
975 
976 /*
977  * Deallocate a session descriptor.
978  */
979 static void
980 free_session(session_t *sp)
981 {
982 	free(sp->se_device);
983 	if (sp->se_getty) {
984 		free(sp->se_getty);
985 		free(sp->se_getty_argv_space);
986 		free(sp->se_getty_argv);
987 	}
988 	if (sp->se_window) {
989 		free(sp->se_window);
990 		free(sp->se_window_argv_space);
991 		free(sp->se_window_argv);
992 	}
993 	if (sp->se_type)
994 		free(sp->se_type);
995 	free(sp);
996 }
997 
998 /*
999  * Allocate a new session descriptor.
1000  * Mark it SE_PRESENT.
1001  */
1002 static session_t *
1003 new_session(session_t *sprev, int session_index, struct ttyent *typ)
1004 {
1005 	session_t *sp;
1006 	int fd;
1007 
1008 	if ((typ->ty_status & TTY_ON) == 0 ||
1009 	    typ->ty_name == 0 ||
1010 	    typ->ty_getty == 0)
1011 		return 0;
1012 
1013 	sp = (session_t *) calloc(1, sizeof (session_t));
1014 
1015 	sp->se_index = session_index;
1016 	sp->se_flags |= SE_PRESENT;
1017 
1018 	sp->se_device = malloc(sizeof(_PATH_DEV) + strlen(typ->ty_name));
1019 	sprintf(sp->se_device, "%s%s", _PATH_DEV, typ->ty_name);
1020 
1021 	/*
1022 	 * Attempt to open the device, if we get "device not configured"
1023 	 * then don't add the device to the session list.
1024 	 */
1025 	if ((fd = open(sp->se_device, O_RDONLY | O_NONBLOCK, 0)) < 0) {
1026 		if (errno == ENXIO) {
1027 			free_session(sp);
1028 			return (0);
1029 		}
1030 	} else
1031 		close(fd);
1032 
1033 	if (setupargv(sp, typ) == 0) {
1034 		free_session(sp);
1035 		return (0);
1036 	}
1037 
1038 	sp->se_next = 0;
1039 	if (sprev == 0) {
1040 		sessions = sp;
1041 		sp->se_prev = 0;
1042 	} else {
1043 		sprev->se_next = sp;
1044 		sp->se_prev = sprev;
1045 	}
1046 
1047 	return sp;
1048 }
1049 
1050 /*
1051  * Calculate getty and if useful window argv vectors.
1052  */
1053 static int
1054 setupargv(session_t *sp, struct ttyent *typ)
1055 {
1056 
1057 	if (sp->se_getty) {
1058 		free(sp->se_getty);
1059 		free(sp->se_getty_argv_space);
1060 		free(sp->se_getty_argv);
1061 	}
1062 	sp->se_getty = malloc(strlen(typ->ty_getty) + strlen(typ->ty_name) + 2);
1063 	sprintf(sp->se_getty, "%s %s", typ->ty_getty, typ->ty_name);
1064 	sp->se_getty_argv_space = strdup(sp->se_getty);
1065 	sp->se_getty_argv = construct_argv(sp->se_getty_argv_space);
1066 	if (sp->se_getty_argv == 0) {
1067 		warning("can't parse getty for port %s", sp->se_device);
1068 		free(sp->se_getty);
1069 		free(sp->se_getty_argv_space);
1070 		sp->se_getty = sp->se_getty_argv_space = 0;
1071 		return (0);
1072 	}
1073 	if (sp->se_window) {
1074 		free(sp->se_window);
1075 		free(sp->se_window_argv_space);
1076 		free(sp->se_window_argv);
1077 	}
1078 	sp->se_window = sp->se_window_argv_space = 0;
1079 	sp->se_window_argv = 0;
1080 	if (typ->ty_window) {
1081 		sp->se_window = strdup(typ->ty_window);
1082 		sp->se_window_argv_space = strdup(sp->se_window);
1083 		sp->se_window_argv = construct_argv(sp->se_window_argv_space);
1084 		if (sp->se_window_argv == 0) {
1085 			warning("can't parse window for port %s",
1086 			    sp->se_device);
1087 			free(sp->se_window_argv_space);
1088 			free(sp->se_window);
1089 			sp->se_window = sp->se_window_argv_space = 0;
1090 			return (0);
1091 		}
1092 	}
1093 	if (sp->se_type)
1094 		free(sp->se_type);
1095 	sp->se_type = typ->ty_type ? strdup(typ->ty_type) : 0;
1096 	return (1);
1097 }
1098 
1099 /*
1100  * Walk the list of ttys and create sessions for each active line.
1101  */
1102 static state_func_t
1103 read_ttys(void)
1104 {
1105 	int session_index = 0;
1106 	session_t *sp, *snext;
1107 	struct ttyent *typ;
1108 
1109 	/*
1110 	 * Destroy any previous session state.
1111 	 * There shouldn't be any, but just in case...
1112 	 */
1113 	for (sp = sessions; sp; sp = snext) {
1114 		if (sp->se_process)
1115 			clear_session_logs(sp);
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, ++session_index, 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 	clear_session_logs(sp);
1270 	del_session(sp);
1271 	sp->se_process = 0;
1272 
1273 	if (sp->se_flags & SE_SHUTDOWN) {
1274 		if ((sprev = sp->se_prev) != NULL)
1275 			sprev->se_next = sp->se_next;
1276 		else
1277 			sessions = sp->se_next;
1278 		if ((snext = sp->se_next) != NULL)
1279 			snext->se_prev = sp->se_prev;
1280 		free_session(sp);
1281 		return;
1282 	}
1283 
1284 	if ((pid = start_getty(sp)) == -1) {
1285 		/* serious trouble */
1286 		requested_transition = clean_ttys;
1287 		return;
1288 	}
1289 
1290 	sp->se_process = pid;
1291 	sp->se_started = time((time_t *) 0);
1292 	add_session(sp);
1293 }
1294 
1295 /*
1296  * Catch a signal and request a state transition.
1297  */
1298 static void
1299 transition_handler(int sig)
1300 {
1301 
1302 	switch (sig) {
1303 	case SIGHUP:
1304 		requested_transition = clean_ttys;
1305 		break;
1306 	case SIGUSR2:
1307 		howto = RB_POWEROFF;
1308 	case SIGUSR1:
1309 		howto |= RB_HALT;
1310 	case SIGINT:
1311 		Reboot = TRUE;
1312 	case SIGTERM:
1313 		requested_transition = death;
1314 		break;
1315 	case SIGTSTP:
1316 		requested_transition = catatonia;
1317 		break;
1318 	default:
1319 		requested_transition = 0;
1320 		break;
1321 	}
1322 }
1323 
1324 /*
1325  * Take the system multiuser.
1326  */
1327 static state_func_t
1328 multi_user(void)
1329 {
1330 	pid_t pid;
1331 	session_t *sp;
1332 
1333 	requested_transition = 0;
1334 
1335 	/*
1336 	 * If the administrator has not set the security level to -1
1337 	 * to indicate that the kernel should not run multiuser in secure
1338 	 * mode, and the run script has not set a higher level of security
1339 	 * than level 1, then put the kernel into secure mode.
1340 	 */
1341 	if (getsecuritylevel() == 0)
1342 		setsecuritylevel(1);
1343 
1344 	for (sp = sessions; sp; sp = sp->se_next) {
1345 		if (sp->se_process)
1346 			continue;
1347 		if ((pid = start_getty(sp)) == -1) {
1348 			/* serious trouble */
1349 			requested_transition = clean_ttys;
1350 			break;
1351 		}
1352 		sp->se_process = pid;
1353 		sp->se_started = time((time_t *) 0);
1354 		add_session(sp);
1355 	}
1356 
1357 	while (!requested_transition)
1358 		if ((pid = waitpid(-1, (int *) 0, 0)) != -1)
1359 			collect_child(pid);
1360 
1361 	return (state_func_t) requested_transition;
1362 }
1363 
1364 /*
1365  * This is an (n*2)+(n^2) algorithm.  We hope it isn't run often...
1366  */
1367 static state_func_t
1368 clean_ttys(void)
1369 {
1370 	session_t *sp, *sprev;
1371 	struct ttyent *typ;
1372 	int session_index = 0;
1373 	int devlen;
1374 	char *old_getty, *old_window, *old_type;
1375 
1376 	/*
1377 	 * mark all sessions for death, (!SE_PRESENT)
1378 	 * as we find or create new ones they'll be marked as keepers,
1379 	 * we'll later nuke all the ones not found in /etc/ttys
1380 	 */
1381 	for (sp = sessions; sp != NULL; sp = sp->se_next)
1382 		sp->se_flags &= ~SE_PRESENT;
1383 
1384 	devlen = sizeof(_PATH_DEV) - 1;
1385 	while ((typ = getttyent()) != NULL) {
1386 		++session_index;
1387 
1388 		for (sprev = 0, sp = sessions; sp; sprev = sp, sp = sp->se_next)
1389 			if (strcmp(typ->ty_name, sp->se_device + devlen) == 0)
1390 				break;
1391 
1392 		if (sp) {
1393 			/* we want this one to live */
1394 			sp->se_flags |= SE_PRESENT;
1395 			if (sp->se_index != session_index) {
1396 				warning("port %s changed utmp index from %d to %d",
1397 				       sp->se_device, sp->se_index,
1398 				       session_index);
1399 				sp->se_index = session_index;
1400 			}
1401 			if ((typ->ty_status & TTY_ON) == 0 ||
1402 			    typ->ty_getty == 0) {
1403 				sp->se_flags |= SE_SHUTDOWN;
1404 				kill(sp->se_process, SIGHUP);
1405 				continue;
1406 			}
1407 			sp->se_flags &= ~SE_SHUTDOWN;
1408 			old_getty = sp->se_getty ? strdup(sp->se_getty) : 0;
1409 			old_window = sp->se_window ? strdup(sp->se_window) : 0;
1410 			old_type = sp->se_type ? strdup(sp->se_type) : 0;
1411 			if (setupargv(sp, typ) == 0) {
1412 				warning("can't parse getty for port %s",
1413 					sp->se_device);
1414 				sp->se_flags |= SE_SHUTDOWN;
1415 				kill(sp->se_process, SIGHUP);
1416 			}
1417 			else if (   !old_getty
1418 				 || (!old_type && sp->se_type)
1419 				 || (old_type && !sp->se_type)
1420 				 || (!old_window && sp->se_window)
1421 				 || (old_window && !sp->se_window)
1422 				 || (strcmp(old_getty, sp->se_getty) != 0)
1423 				 || (old_window && strcmp(old_window, sp->se_window) != 0)
1424 				 || (old_type && strcmp(old_type, sp->se_type) != 0)
1425 				) {
1426 				/* Don't set SE_SHUTDOWN here */
1427 				sp->se_nspace = 0;
1428 				sp->se_started = 0;
1429 				kill(sp->se_process, SIGHUP);
1430 			}
1431 			if (old_getty)
1432 				free(old_getty);
1433 			if (old_window)
1434 				free(old_window);
1435 			if (old_type)
1436 				free(old_type);
1437 			continue;
1438 		}
1439 
1440 		new_session(sprev, session_index, typ);
1441 	}
1442 
1443 	endttyent();
1444 
1445 	/*
1446 	 * sweep through and kill all deleted sessions
1447 	 * ones who's /etc/ttys line was deleted (SE_PRESENT unset)
1448 	 */
1449 	for (sp = sessions; sp != NULL; sp = sp->se_next) {
1450 		if ((sp->se_flags & SE_PRESENT) == 0) {
1451 			sp->se_flags |= SE_SHUTDOWN;
1452 			kill(sp->se_process, SIGHUP);
1453 		}
1454 	}
1455 
1456 	return (state_func_t) multi_user;
1457 }
1458 
1459 /*
1460  * Block further logins.
1461  */
1462 static state_func_t
1463 catatonia(void)
1464 {
1465 	session_t *sp;
1466 
1467 	for (sp = sessions; sp; sp = sp->se_next)
1468 		sp->se_flags |= SE_SHUTDOWN;
1469 
1470 	return (state_func_t) multi_user;
1471 }
1472 
1473 /*
1474  * Note SIGALRM.
1475  */
1476 static void
1477 alrm_handler(int sig)
1478 {
1479 
1480 	(void)sig;
1481 	clang = 1;
1482 }
1483 
1484 /*
1485  * Bring the system down to single user.
1486  */
1487 static state_func_t
1488 death(void)
1489 {
1490 	session_t *sp;
1491 	int i;
1492 	pid_t pid;
1493 	static const int death_sigs[2] = { SIGTERM, SIGKILL };
1494 
1495 	/* NB: should send a message to the session logger to avoid blocking. */
1496 	logwtmp("~", "shutdown", "");
1497 
1498 	for (sp = sessions; sp; sp = sp->se_next) {
1499 		sp->se_flags |= SE_SHUTDOWN;
1500 		kill(sp->se_process, SIGHUP);
1501 	}
1502 
1503 	/* Try to run the rc.shutdown script within a period of time */
1504 	runshutdown();
1505 
1506 	for (i = 0; i < 2; ++i) {
1507 		if (kill(-1, death_sigs[i]) == -1 && errno == ESRCH)
1508 			return (state_func_t) single_user;
1509 
1510 		clang = 0;
1511 		alarm(DEATH_WATCH);
1512 		do
1513 			if ((pid = waitpid(-1, (int *)0, 0)) != -1)
1514 				collect_child(pid);
1515 		while (clang == 0 && errno != ECHILD);
1516 
1517 		if (errno == ECHILD)
1518 			return (state_func_t) single_user;
1519 	}
1520 
1521 	warning("some processes would not die; ps axl advised");
1522 
1523 	return (state_func_t) single_user;
1524 }
1525 
1526 /*
1527  * Run the system shutdown script.
1528  *
1529  * Exit codes:      XXX I should document more
1530  * -2       shutdown script terminated abnormally
1531  * -1       fatal error - can't run script
1532  * 0        good.
1533  * >0       some error (exit code)
1534  */
1535 static int
1536 runshutdown(void)
1537 {
1538 	pid_t pid, wpid;
1539 	int status;
1540 	int shutdowntimeout;
1541 	size_t len;
1542 	char *argv[4];
1543 	const char *shell;
1544 	struct sigaction sa;
1545 	struct stat sb;
1546 
1547 	/*
1548 	 * rc.shutdown is optional, so to prevent any unnecessary
1549 	 * complaints from the shell we simply don't run it if the
1550 	 * file does not exist. If the stat() here fails for other
1551 	 * reasons, we'll let the shell complain.
1552 	 */
1553 	if (stat(_PATH_RUNDOWN, &sb) == -1 && errno == ENOENT)
1554 		return 0;
1555 
1556 	shell = get_shell();
1557 
1558 	if ((pid = fork()) == 0) {
1559 		int	fd;
1560 
1561 		/* Assume that init already grab console as ctty before */
1562 
1563 		sigemptyset(&sa.sa_mask);
1564 		sa.sa_flags = 0;
1565 		sa.sa_handler = SIG_IGN;
1566 		sigaction(SIGTSTP, &sa, (struct sigaction *)0);
1567 		sigaction(SIGHUP, &sa, (struct sigaction *)0);
1568 
1569 		if ((fd = open(_PATH_CONSOLE, O_RDWR)) == -1)
1570 			warning("can't open %s: %m", _PATH_CONSOLE);
1571 		else {
1572 			dup2(fd, 0);
1573 			dup2(fd, 1);
1574 			dup2(fd, 2);
1575 			if (fd > 2)
1576 				close(fd);
1577 		}
1578 
1579 		/*
1580 		 * Run the shutdown script.
1581 		 */
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_close(lc);
1722 	}
1723 }
1724 #endif
1725