xref: /freebsd/sbin/init/init.c (revision 984485a02eb3e63b4170dd911b72de38b35b2289)
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 <ulog.h>
69 #include <unistd.h>
70 #include <utmpx.h>
71 #include <sys/reboot.h>
72 #include <err.h>
73 
74 #include <stdarg.h>
75 
76 #ifdef SECURE
77 #include <pwd.h>
78 #endif
79 
80 #ifdef LOGIN_CAP
81 #include <login_cap.h>
82 #endif
83 
84 #include "pathnames.h"
85 
86 /*
87  * Sleep times; used to prevent thrashing.
88  */
89 #define	GETTY_SPACING		 5	/* N secs minimum getty spacing */
90 #define	GETTY_SLEEP		30	/* sleep N secs after spacing problem */
91 #define	GETTY_NSPACE             3      /* max. spacing count to bring reaction */
92 #define	WINDOW_WAIT		 3	/* wait N secs after starting window */
93 #define	STALL_TIMEOUT		30	/* wait N secs after warning */
94 #define	DEATH_WATCH		10	/* wait N secs for procs to die */
95 #define	DEATH_SCRIPT		120	/* wait for 2min for /etc/rc.shutdown */
96 #define	RESOURCE_RC		"daemon"
97 #define	RESOURCE_WINDOW 	"default"
98 #define	RESOURCE_GETTY		"default"
99 
100 static void handle(sig_t, ...);
101 static void delset(sigset_t *, ...);
102 
103 static void stall(const char *, ...) __printflike(1, 2);
104 static void warning(const char *, ...) __printflike(1, 2);
105 static void emergency(const char *, ...) __printflike(1, 2);
106 static void disaster(int);
107 static void badsys(int);
108 static int  runshutdown(void);
109 static char *strk(char *);
110 
111 /*
112  * We really need a recursive typedef...
113  * The following at least guarantees that the return type of (*state_t)()
114  * is sufficiently wide to hold a function pointer.
115  */
116 typedef long (*state_func_t)(void);
117 typedef state_func_t (*state_t)(void);
118 
119 static state_func_t single_user(void);
120 static state_func_t runcom(void);
121 static state_func_t read_ttys(void);
122 static state_func_t multi_user(void);
123 static state_func_t clean_ttys(void);
124 static state_func_t catatonia(void);
125 static state_func_t death(void);
126 
127 static state_func_t run_script(const char *);
128 
129 enum { AUTOBOOT, FASTBOOT } runcom_mode = AUTOBOOT;
130 #define FALSE	0
131 #define TRUE	1
132 
133 int Reboot = FALSE;
134 int howto = RB_AUTOBOOT;
135 
136 int devfs;
137 
138 static void transition(state_t);
139 static state_t requested_transition;
140 
141 static void setctty(const char *);
142 static const char *get_shell(void);
143 static void write_stderr(const char *message);
144 
145 typedef struct init_session {
146 	int	se_index;		/* index of entry in ttys file */
147 	pid_t	se_process;		/* controlling process */
148 	time_t	se_started;		/* used to avoid thrashing */
149 	int	se_flags;		/* status of session */
150 #define	SE_SHUTDOWN	0x1		/* session won't be restarted */
151 #define	SE_PRESENT	0x2		/* session is in /etc/ttys */
152 	int     se_nspace;              /* spacing count */
153 	char	*se_device;		/* filename of port */
154 	char	*se_getty;		/* what to run on that port */
155 	char    *se_getty_argv_space;   /* pre-parsed argument array space */
156 	char	**se_getty_argv;	/* pre-parsed argument array */
157 	char	*se_window;		/* window system (started only once) */
158 	char    *se_window_argv_space;  /* pre-parsed argument array space */
159 	char	**se_window_argv;	/* pre-parsed argument array */
160 	char    *se_type;               /* default terminal type */
161 	struct	init_session *se_prev;
162 	struct	init_session *se_next;
163 } session_t;
164 
165 static void free_session(session_t *);
166 static session_t *new_session(session_t *, int, struct ttyent *);
167 static session_t *sessions;
168 
169 static char **construct_argv(char *);
170 static void start_window_system(session_t *);
171 static void collect_child(pid_t);
172 static pid_t start_getty(session_t *);
173 static void transition_handler(int);
174 static void alrm_handler(int);
175 static void setsecuritylevel(int);
176 static int getsecuritylevel(void);
177 static int setupargv(session_t *, struct ttyent *);
178 #ifdef LOGIN_CAP
179 static void setprocresources(const char *);
180 #endif
181 static int clang;
182 
183 static void clear_session_logs(session_t *);
184 
185 static int start_session_db(void);
186 static void add_session(session_t *);
187 static void del_session(session_t *);
188 static session_t *find_session(pid_t);
189 static DB *session_db;
190 
191 /*
192  * The mother of all processes.
193  */
194 int
195 main(int argc, char *argv[])
196 {
197 	state_t initial_transition = runcom;
198 	char kenv_value[PATH_MAX];
199 	int c;
200 	struct sigaction sa;
201 	sigset_t mask;
202 
203 	/* Dispose of random users. */
204 	if (getuid() != 0)
205 		errx(1, "%s", strerror(EPERM));
206 
207 	/* System V users like to reexec init. */
208 	if (getpid() != 1) {
209 #ifdef COMPAT_SYSV_INIT
210 		/* So give them what they want */
211 		if (argc > 1) {
212 			if (strlen(argv[1]) == 1) {
213 				char runlevel = *argv[1];
214 				int sig;
215 
216 				switch (runlevel) {
217 				case '0': /* halt + poweroff */
218 					sig = SIGUSR2;
219 					break;
220 				case '1': /* single-user */
221 					sig = SIGTERM;
222 					break;
223 				case '6': /* reboot */
224 					sig = SIGINT;
225 					break;
226 				case 'c': /* block further logins */
227 					sig = SIGTSTP;
228 					break;
229 				case 'q': /* rescan /etc/ttys */
230 					sig = SIGHUP;
231 					break;
232 				default:
233 					goto invalid;
234 				}
235 				kill(1, sig);
236 				_exit(0);
237 			} else
238 invalid:
239 				errx(1, "invalid run-level ``%s''", argv[1]);
240 		} else
241 #endif
242 			errx(1, "already running");
243 	}
244 	/*
245 	 * Note that this does NOT open a file...
246 	 * Does 'init' deserve its own facility number?
247 	 */
248 	openlog("init", LOG_CONS|LOG_ODELAY, LOG_AUTH);
249 
250 	/*
251 	 * Create an initial session.
252 	 */
253 	if (setsid() < 0)
254 		warning("initial setsid() failed: %m");
255 
256 	/*
257 	 * Establish an initial user so that programs running
258 	 * single user do not freak out and die (like passwd).
259 	 */
260 	if (setlogin("root") < 0)
261 		warning("setlogin() failed: %m");
262 
263 	/*
264 	 * This code assumes that we always get arguments through flags,
265 	 * never through bits set in some random machine register.
266 	 */
267 	while ((c = getopt(argc, argv, "dsf")) != -1)
268 		switch (c) {
269 		case 'd':
270 			devfs = 1;
271 			break;
272 		case 's':
273 			initial_transition = single_user;
274 			break;
275 		case 'f':
276 			runcom_mode = FASTBOOT;
277 			break;
278 		default:
279 			warning("unrecognized flag '-%c'", c);
280 			break;
281 		}
282 
283 	if (optind != argc)
284 		warning("ignoring excess arguments");
285 
286 	/*
287 	 * We catch or block signals rather than ignore them,
288 	 * so that they get reset on exec.
289 	 */
290 	handle(badsys, SIGSYS, 0);
291 	handle(disaster, SIGABRT, SIGFPE, SIGILL, SIGSEGV, SIGBUS, SIGXCPU,
292 	    SIGXFSZ, 0);
293 	handle(transition_handler, SIGHUP, SIGINT, SIGTERM, SIGTSTP, SIGUSR1,
294 	    SIGUSR2, 0);
295 	handle(alrm_handler, SIGALRM, 0);
296 	sigfillset(&mask);
297 	delset(&mask, SIGABRT, SIGFPE, SIGILL, SIGSEGV, SIGBUS, SIGSYS,
298 	    SIGXCPU, SIGXFSZ, SIGHUP, SIGINT, SIGTERM, SIGTSTP, SIGALRM,
299 	    SIGUSR1, SIGUSR2, 0);
300 	sigprocmask(SIG_SETMASK, &mask, (sigset_t *) 0);
301 	sigemptyset(&sa.sa_mask);
302 	sa.sa_flags = 0;
303 	sa.sa_handler = SIG_IGN;
304 	sigaction(SIGTTIN, &sa, (struct sigaction *)0);
305 	sigaction(SIGTTOU, &sa, (struct sigaction *)0);
306 
307 	/*
308 	 * Paranoia.
309 	 */
310 	close(0);
311 	close(1);
312 	close(2);
313 
314 	if (kenv(KENV_GET, "init_script", kenv_value, sizeof(kenv_value)) > 0) {
315 		state_func_t next_transition;
316 
317 		if ((next_transition = run_script(kenv_value)) != 0)
318 			initial_transition = (state_t) next_transition;
319 	}
320 
321 	if (kenv(KENV_GET, "init_chroot", kenv_value, sizeof(kenv_value)) > 0) {
322 		if (chdir(kenv_value) != 0 || chroot(".") != 0)
323 			warning("Can't chroot to %s: %m", kenv_value);
324 	}
325 
326 	/*
327 	 * Additional check if devfs needs to be mounted:
328 	 * If "/" and "/dev" have the same device number,
329 	 * then it hasn't been mounted yet.
330 	 */
331 	if (!devfs) {
332 		struct stat stst;
333 		dev_t root_devno;
334 
335 		stat("/", &stst);
336 		root_devno = stst.st_dev;
337 		if (stat("/dev", &stst) != 0)
338 			warning("Can't stat /dev: %m");
339 		else if (stst.st_dev == root_devno)
340 			devfs++;
341 	}
342 
343 	if (devfs) {
344 		struct iovec iov[4];
345 		char *s;
346 		int i;
347 
348 		char _fstype[]	= "fstype";
349 		char _devfs[]	= "devfs";
350 		char _fspath[]	= "fspath";
351 		char _path_dev[]= _PATH_DEV;
352 
353 		iov[0].iov_base = _fstype;
354 		iov[0].iov_len = sizeof(_fstype);
355 		iov[1].iov_base = _devfs;
356 		iov[1].iov_len = sizeof(_devfs);
357 		iov[2].iov_base = _fspath;
358 		iov[2].iov_len = sizeof(_fspath);
359 		/*
360 		 * Try to avoid the trailing slash in _PATH_DEV.
361 		 * Be *very* defensive.
362 		 */
363 		s = strdup(_PATH_DEV);
364 		if (s != NULL) {
365 			i = strlen(s);
366 			if (i > 0 && s[i - 1] == '/')
367 				s[i - 1] = '\0';
368 			iov[3].iov_base = s;
369 			iov[3].iov_len = strlen(s) + 1;
370 		} else {
371 			iov[3].iov_base = _path_dev;
372 			iov[3].iov_len = sizeof(_path_dev);
373 		}
374 		nmount(iov, 4, 0);
375 		if (s != NULL)
376 			free(s);
377 	}
378 
379 	/*
380 	 * Start the state machine.
381 	 */
382 	transition(initial_transition);
383 
384 	/*
385 	 * Should never reach here.
386 	 */
387 	return 1;
388 }
389 
390 /*
391  * Associate a function with a signal handler.
392  */
393 static void
394 handle(sig_t handler, ...)
395 {
396 	int sig;
397 	struct sigaction sa;
398 	sigset_t mask_everything;
399 	va_list ap;
400 	va_start(ap, handler);
401 
402 	sa.sa_handler = handler;
403 	sigfillset(&mask_everything);
404 
405 	while ((sig = va_arg(ap, int)) != 0) {
406 		sa.sa_mask = mask_everything;
407 		/* XXX SA_RESTART? */
408 		sa.sa_flags = sig == SIGCHLD ? SA_NOCLDSTOP : 0;
409 		sigaction(sig, &sa, (struct sigaction *) 0);
410 	}
411 	va_end(ap);
412 }
413 
414 /*
415  * Delete a set of signals from a mask.
416  */
417 static void
418 delset(sigset_t *maskp, ...)
419 {
420 	int sig;
421 	va_list ap;
422 	va_start(ap, maskp);
423 
424 	while ((sig = va_arg(ap, int)) != 0)
425 		sigdelset(maskp, sig);
426 	va_end(ap);
427 }
428 
429 /*
430  * Log a message and sleep for a while (to give someone an opportunity
431  * to read it and to save log or hardcopy output if the problem is chronic).
432  * NB: should send a message to the session logger to avoid blocking.
433  */
434 static void
435 stall(const char *message, ...)
436 {
437 	va_list ap;
438 	va_start(ap, message);
439 
440 	vsyslog(LOG_ALERT, message, ap);
441 	va_end(ap);
442 	sleep(STALL_TIMEOUT);
443 }
444 
445 /*
446  * Like stall(), but doesn't sleep.
447  * If cpp had variadic macros, the two functions could be #defines for another.
448  * NB: should send a message to the session logger to avoid blocking.
449  */
450 static void
451 warning(const char *message, ...)
452 {
453 	va_list ap;
454 	va_start(ap, message);
455 
456 	vsyslog(LOG_ALERT, message, ap);
457 	va_end(ap);
458 }
459 
460 /*
461  * Log an emergency message.
462  * NB: should send a message to the session logger to avoid blocking.
463  */
464 static void
465 emergency(const char *message, ...)
466 {
467 	va_list ap;
468 	va_start(ap, message);
469 
470 	vsyslog(LOG_EMERG, message, ap);
471 	va_end(ap);
472 }
473 
474 /*
475  * Catch a SIGSYS signal.
476  *
477  * These may arise if a system does not support sysctl.
478  * We tolerate up to 25 of these, then throw in the towel.
479  */
480 static void
481 badsys(int sig)
482 {
483 	static int badcount = 0;
484 
485 	if (badcount++ < 25)
486 		return;
487 	disaster(sig);
488 }
489 
490 /*
491  * Catch an unexpected signal.
492  */
493 static void
494 disaster(int sig)
495 {
496 
497 	emergency("fatal signal: %s",
498 	    (unsigned)sig < NSIG ? sys_siglist[sig] : "unknown signal");
499 
500 	sleep(STALL_TIMEOUT);
501 	_exit(sig);		/* reboot */
502 }
503 
504 /*
505  * Get the security level of the kernel.
506  */
507 static int
508 getsecuritylevel(void)
509 {
510 #ifdef KERN_SECURELVL
511 	int name[2], curlevel;
512 	size_t len;
513 
514 	name[0] = CTL_KERN;
515 	name[1] = KERN_SECURELVL;
516 	len = sizeof curlevel;
517 	if (sysctl(name, 2, &curlevel, &len, NULL, 0) == -1) {
518 		emergency("cannot get kernel security level: %s",
519 		    strerror(errno));
520 		return (-1);
521 	}
522 	return (curlevel);
523 #else
524 	return (-1);
525 #endif
526 }
527 
528 /*
529  * Set the security level of the kernel.
530  */
531 static void
532 setsecuritylevel(int newlevel)
533 {
534 #ifdef KERN_SECURELVL
535 	int name[2], curlevel;
536 
537 	curlevel = getsecuritylevel();
538 	if (newlevel == curlevel)
539 		return;
540 	name[0] = CTL_KERN;
541 	name[1] = KERN_SECURELVL;
542 	if (sysctl(name, 2, NULL, NULL, &newlevel, sizeof newlevel) == -1) {
543 		emergency(
544 		    "cannot change kernel security level from %d to %d: %s",
545 		    curlevel, newlevel, strerror(errno));
546 		return;
547 	}
548 #ifdef SECURE
549 	warning("kernel security level changed from %d to %d",
550 	    curlevel, newlevel);
551 #endif
552 #endif
553 }
554 
555 /*
556  * Change states in the finite state machine.
557  * The initial state is passed as an argument.
558  */
559 static void
560 transition(state_t s)
561 {
562 
563 	for (;;)
564 		s = (state_t) (*s)();
565 }
566 
567 /*
568  * Close out the accounting files for a login session.
569  * NB: should send a message to the session logger to avoid blocking.
570  */
571 static void
572 clear_session_logs(session_t *sp __unused)
573 {
574 
575 	/*
576 	 * XXX: Use getutxline() and call pututxline() for each entry.
577 	 * Is this safe to do this here?  Is it really required anyway?
578 	 */
579 }
580 
581 /*
582  * Start a session and allocate a controlling terminal.
583  * Only called by children of init after forking.
584  */
585 static void
586 setctty(const char *name)
587 {
588 	int fd;
589 
590 	revoke(name);
591 	if ((fd = open(name, O_RDWR)) == -1) {
592 		stall("can't open %s: %m", name);
593 		_exit(1);
594 	}
595 	if (login_tty(fd) == -1) {
596 		stall("can't get %s for controlling terminal: %m", name);
597 		_exit(1);
598 	}
599 }
600 
601 static const char *
602 get_shell(void)
603 {
604 	static char kenv_value[PATH_MAX];
605 
606 	if (kenv(KENV_GET, "init_shell", kenv_value, sizeof(kenv_value)) > 0)
607 		return kenv_value;
608 	else
609 		return _PATH_BSHELL;
610 }
611 
612 static void
613 write_stderr(const char *message)
614 {
615 
616 	write(STDERR_FILENO, message, strlen(message));
617 }
618 
619 /*
620  * Bring the system up single user.
621  */
622 static state_func_t
623 single_user(void)
624 {
625 	pid_t pid, wpid;
626 	int status;
627 	sigset_t mask;
628 	const char *shell;
629 	char *argv[2];
630 #ifdef SECURE
631 	struct ttyent *typ;
632 	struct passwd *pp;
633 	static const char banner[] =
634 		"Enter root password, or ^D to go multi-user\n";
635 	char *clear, *password;
636 #endif
637 #ifdef DEBUGSHELL
638 	char altshell[128];
639 #endif
640 
641 	if (Reboot) {
642 		/* Instead of going single user, let's reboot the machine */
643 		sync();
644 		alarm(2);
645 		pause();
646 		reboot(howto);
647 		_exit(0);
648 	}
649 
650 	shell = get_shell();
651 
652 	if ((pid = fork()) == 0) {
653 		/*
654 		 * Start the single user session.
655 		 */
656 		setctty(_PATH_CONSOLE);
657 
658 #ifdef SECURE
659 		/*
660 		 * Check the root password.
661 		 * We don't care if the console is 'on' by default;
662 		 * it's the only tty that can be 'off' and 'secure'.
663 		 */
664 		typ = getttynam("console");
665 		pp = getpwnam("root");
666 		if (typ && (typ->ty_status & TTY_SECURE) == 0 &&
667 		    pp && *pp->pw_passwd) {
668 			write_stderr(banner);
669 			for (;;) {
670 				clear = getpass("Password:");
671 				if (clear == 0 || *clear == '\0')
672 					_exit(0);
673 				password = crypt(clear, pp->pw_passwd);
674 				bzero(clear, _PASSWORD_LEN);
675 				if (strcmp(password, pp->pw_passwd) == 0)
676 					break;
677 				warning("single-user login failed\n");
678 			}
679 		}
680 		endttyent();
681 		endpwent();
682 #endif /* SECURE */
683 
684 #ifdef DEBUGSHELL
685 		{
686 			char *cp = altshell;
687 			int num;
688 
689 #define	SHREQUEST "Enter full pathname of shell or RETURN for "
690 			write_stderr(SHREQUEST);
691 			write_stderr(shell);
692 			write_stderr(": ");
693 			while ((num = read(STDIN_FILENO, cp, 1)) != -1 &&
694 			    num != 0 && *cp != '\n' && cp < &altshell[127])
695 				cp++;
696 			*cp = '\0';
697 			if (altshell[0] != '\0')
698 				shell = altshell;
699 		}
700 #endif /* DEBUGSHELL */
701 
702 		/*
703 		 * Unblock signals.
704 		 * We catch all the interesting ones,
705 		 * and those are reset to SIG_DFL on exec.
706 		 */
707 		sigemptyset(&mask);
708 		sigprocmask(SIG_SETMASK, &mask, (sigset_t *) 0);
709 
710 		/*
711 		 * Fire off a shell.
712 		 * If the default one doesn't work, try the Bourne shell.
713 		 */
714 
715 		char name[] = "-sh";
716 
717 		argv[0] = name;
718 		argv[1] = 0;
719 		execv(shell, argv);
720 		emergency("can't exec %s for single user: %m", shell);
721 		execv(_PATH_BSHELL, argv);
722 		emergency("can't exec %s for single user: %m", _PATH_BSHELL);
723 		sleep(STALL_TIMEOUT);
724 		_exit(1);
725 	}
726 
727 	if (pid == -1) {
728 		/*
729 		 * We are seriously hosed.  Do our best.
730 		 */
731 		emergency("can't fork single-user shell, trying again");
732 		while (waitpid(-1, (int *) 0, WNOHANG) > 0)
733 			continue;
734 		return (state_func_t) single_user;
735 	}
736 
737 	requested_transition = 0;
738 	do {
739 		if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1)
740 			collect_child(wpid);
741 		if (wpid == -1) {
742 			if (errno == EINTR)
743 				continue;
744 			warning("wait for single-user shell failed: %m; restarting");
745 			return (state_func_t) single_user;
746 		}
747 		if (wpid == pid && WIFSTOPPED(status)) {
748 			warning("init: shell stopped, restarting\n");
749 			kill(pid, SIGCONT);
750 			wpid = -1;
751 		}
752 	} while (wpid != pid && !requested_transition);
753 
754 	if (requested_transition)
755 		return (state_func_t) requested_transition;
756 
757 	if (!WIFEXITED(status)) {
758 		if (WTERMSIG(status) == SIGKILL) {
759 			/*
760 			 *  reboot(8) killed shell?
761 			 */
762 			warning("single user shell terminated.");
763 			sleep(STALL_TIMEOUT);
764 			_exit(0);
765 		} else {
766 			warning("single user shell terminated, restarting");
767 			return (state_func_t) single_user;
768 		}
769 	}
770 
771 	runcom_mode = FASTBOOT;
772 	return (state_func_t) runcom;
773 }
774 
775 /*
776  * Run the system startup script.
777  */
778 static state_func_t
779 runcom(void)
780 {
781 	struct utmpx utx;
782 	state_func_t next_transition;
783 
784 	if ((next_transition = run_script(_PATH_RUNCOM)) != 0)
785 		return next_transition;
786 
787 	runcom_mode = AUTOBOOT;		/* the default */
788 	/* NB: should send a message to the session logger to avoid blocking. */
789 	utx.ut_type = BOOT_TIME;
790 	gettimeofday(&utx.ut_tv, NULL);
791 	pututxline(&utx);
792 	return (state_func_t) read_ttys;
793 }
794 
795 /*
796  * Run a shell script.
797  * Returns 0 on success, otherwise the next transition to enter:
798  *  - single_user if fork/execv/waitpid failed, or if the script
799  *    terminated with a signal or exit code != 0.
800  *  - death if a SIGTERM was delivered to init(8).
801  */
802 static state_func_t
803 run_script(const char *script)
804 {
805 	pid_t pid, wpid;
806 	int status;
807 	char *argv[4];
808 	const char *shell;
809 	struct sigaction sa;
810 
811 	shell = get_shell();
812 
813 	if ((pid = fork()) == 0) {
814 		sigemptyset(&sa.sa_mask);
815 		sa.sa_flags = 0;
816 		sa.sa_handler = SIG_IGN;
817 		sigaction(SIGTSTP, &sa, (struct sigaction *)0);
818 		sigaction(SIGHUP, &sa, (struct sigaction *)0);
819 
820 		setctty(_PATH_CONSOLE);
821 
822 		char _sh[]	 	= "sh";
823 		char _autoboot[]	= "autoboot";
824 
825 		argv[0] = _sh;
826 		argv[1] = __DECONST(char *, script);
827 		argv[2] = runcom_mode == AUTOBOOT ? _autoboot : 0;
828 		argv[3] = 0;
829 
830 		sigprocmask(SIG_SETMASK, &sa.sa_mask, (sigset_t *) 0);
831 
832 #ifdef LOGIN_CAP
833 		setprocresources(RESOURCE_RC);
834 #endif
835 		execv(shell, argv);
836 		stall("can't exec %s for %s: %m", shell, script);
837 		_exit(1);	/* force single user mode */
838 	}
839 
840 	if (pid == -1) {
841 		emergency("can't fork for %s on %s: %m", shell, script);
842 		while (waitpid(-1, (int *) 0, WNOHANG) > 0)
843 			continue;
844 		sleep(STALL_TIMEOUT);
845 		return (state_func_t) single_user;
846 	}
847 
848 	/*
849 	 * Copied from single_user().  This is a bit paranoid.
850 	 */
851 	requested_transition = 0;
852 	do {
853 		if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1)
854 			collect_child(wpid);
855 		if (wpid == -1) {
856 			if (requested_transition == death)
857 				return (state_func_t) death;
858 			if (errno == EINTR)
859 				continue;
860 			warning("wait for %s on %s failed: %m; going to "
861 			    "single user mode", shell, script);
862 			return (state_func_t) single_user;
863 		}
864 		if (wpid == pid && WIFSTOPPED(status)) {
865 			warning("init: %s on %s stopped, restarting\n",
866 			    shell, script);
867 			kill(pid, SIGCONT);
868 			wpid = -1;
869 		}
870 	} while (wpid != pid);
871 
872 	if (WIFSIGNALED(status) && WTERMSIG(status) == SIGTERM &&
873 	    requested_transition == catatonia) {
874 		/* /etc/rc executed /sbin/reboot; wait for the end quietly */
875 		sigset_t s;
876 
877 		sigfillset(&s);
878 		for (;;)
879 			sigsuspend(&s);
880 	}
881 
882 	if (!WIFEXITED(status)) {
883 		warning("%s on %s terminated abnormally, going to single "
884 		    "user mode", shell, script);
885 		return (state_func_t) single_user;
886 	}
887 
888 	if (WEXITSTATUS(status))
889 		return (state_func_t) single_user;
890 
891 	return (state_func_t) 0;
892 }
893 
894 /*
895  * Open the session database.
896  *
897  * NB: We could pass in the size here; is it necessary?
898  */
899 static int
900 start_session_db(void)
901 {
902 	if (session_db && (*session_db->close)(session_db))
903 		emergency("session database close: %s", strerror(errno));
904 	if ((session_db = dbopen(NULL, O_RDWR, 0, DB_HASH, NULL)) == 0) {
905 		emergency("session database open: %s", strerror(errno));
906 		return (1);
907 	}
908 	return (0);
909 
910 }
911 
912 /*
913  * Add a new login session.
914  */
915 static void
916 add_session(session_t *sp)
917 {
918 	DBT key;
919 	DBT data;
920 
921 	key.data = &sp->se_process;
922 	key.size = sizeof sp->se_process;
923 	data.data = &sp;
924 	data.size = sizeof sp;
925 
926 	if ((*session_db->put)(session_db, &key, &data, 0))
927 		emergency("insert %d: %s", sp->se_process, strerror(errno));
928 }
929 
930 /*
931  * Delete an old login session.
932  */
933 static void
934 del_session(session_t *sp)
935 {
936 	DBT key;
937 
938 	key.data = &sp->se_process;
939 	key.size = sizeof sp->se_process;
940 
941 	if ((*session_db->del)(session_db, &key, 0))
942 		emergency("delete %d: %s", sp->se_process, strerror(errno));
943 }
944 
945 /*
946  * Look up a login session by pid.
947  */
948 static session_t *
949 find_session(pid_t pid)
950 {
951 	DBT key;
952 	DBT data;
953 	session_t *ret;
954 
955 	key.data = &pid;
956 	key.size = sizeof pid;
957 	if ((*session_db->get)(session_db, &key, &data, 0) != 0)
958 		return 0;
959 	bcopy(data.data, (char *)&ret, sizeof(ret));
960 	return ret;
961 }
962 
963 /*
964  * Construct an argument vector from a command line.
965  */
966 static char **
967 construct_argv(char *command)
968 {
969 	int argc = 0;
970 	char **argv = (char **) malloc(((strlen(command) + 1) / 2 + 1)
971 						* sizeof (char *));
972 
973 	if ((argv[argc++] = strk(command)) == 0) {
974 		free(argv);
975 		return (NULL);
976 	}
977 	while ((argv[argc++] = strk((char *) 0)) != NULL)
978 		continue;
979 	return argv;
980 }
981 
982 /*
983  * Deallocate a session descriptor.
984  */
985 static void
986 free_session(session_t *sp)
987 {
988 	free(sp->se_device);
989 	if (sp->se_getty) {
990 		free(sp->se_getty);
991 		free(sp->se_getty_argv_space);
992 		free(sp->se_getty_argv);
993 	}
994 	if (sp->se_window) {
995 		free(sp->se_window);
996 		free(sp->se_window_argv_space);
997 		free(sp->se_window_argv);
998 	}
999 	if (sp->se_type)
1000 		free(sp->se_type);
1001 	free(sp);
1002 }
1003 
1004 /*
1005  * Allocate a new session descriptor.
1006  * Mark it SE_PRESENT.
1007  */
1008 static session_t *
1009 new_session(session_t *sprev, int session_index, struct ttyent *typ)
1010 {
1011 	session_t *sp;
1012 	int fd;
1013 
1014 	if ((typ->ty_status & TTY_ON) == 0 ||
1015 	    typ->ty_name == 0 ||
1016 	    typ->ty_getty == 0)
1017 		return 0;
1018 
1019 	sp = (session_t *) calloc(1, sizeof (session_t));
1020 
1021 	sp->se_index = session_index;
1022 	sp->se_flags |= SE_PRESENT;
1023 
1024 	sp->se_device = malloc(sizeof(_PATH_DEV) + strlen(typ->ty_name));
1025 	sprintf(sp->se_device, "%s%s", _PATH_DEV, typ->ty_name);
1026 
1027 	/*
1028 	 * Attempt to open the device, if we get "device not configured"
1029 	 * then don't add the device to the session list.
1030 	 */
1031 	if ((fd = open(sp->se_device, O_RDONLY | O_NONBLOCK, 0)) < 0) {
1032 		if (errno == ENXIO) {
1033 			free_session(sp);
1034 			return (0);
1035 		}
1036 	} else
1037 		close(fd);
1038 
1039 	if (setupargv(sp, typ) == 0) {
1040 		free_session(sp);
1041 		return (0);
1042 	}
1043 
1044 	sp->se_next = 0;
1045 	if (sprev == 0) {
1046 		sessions = sp;
1047 		sp->se_prev = 0;
1048 	} else {
1049 		sprev->se_next = sp;
1050 		sp->se_prev = sprev;
1051 	}
1052 
1053 	return sp;
1054 }
1055 
1056 /*
1057  * Calculate getty and if useful window argv vectors.
1058  */
1059 static int
1060 setupargv(session_t *sp, struct ttyent *typ)
1061 {
1062 
1063 	if (sp->se_getty) {
1064 		free(sp->se_getty);
1065 		free(sp->se_getty_argv_space);
1066 		free(sp->se_getty_argv);
1067 	}
1068 	sp->se_getty = malloc(strlen(typ->ty_getty) + strlen(typ->ty_name) + 2);
1069 	sprintf(sp->se_getty, "%s %s", typ->ty_getty, typ->ty_name);
1070 	sp->se_getty_argv_space = strdup(sp->se_getty);
1071 	sp->se_getty_argv = construct_argv(sp->se_getty_argv_space);
1072 	if (sp->se_getty_argv == 0) {
1073 		warning("can't parse getty for port %s", sp->se_device);
1074 		free(sp->se_getty);
1075 		free(sp->se_getty_argv_space);
1076 		sp->se_getty = sp->se_getty_argv_space = 0;
1077 		return (0);
1078 	}
1079 	if (sp->se_window) {
1080 		free(sp->se_window);
1081 		free(sp->se_window_argv_space);
1082 		free(sp->se_window_argv);
1083 	}
1084 	sp->se_window = sp->se_window_argv_space = 0;
1085 	sp->se_window_argv = 0;
1086 	if (typ->ty_window) {
1087 		sp->se_window = strdup(typ->ty_window);
1088 		sp->se_window_argv_space = strdup(sp->se_window);
1089 		sp->se_window_argv = construct_argv(sp->se_window_argv_space);
1090 		if (sp->se_window_argv == 0) {
1091 			warning("can't parse window for port %s",
1092 			    sp->se_device);
1093 			free(sp->se_window_argv_space);
1094 			free(sp->se_window);
1095 			sp->se_window = sp->se_window_argv_space = 0;
1096 			return (0);
1097 		}
1098 	}
1099 	if (sp->se_type)
1100 		free(sp->se_type);
1101 	sp->se_type = typ->ty_type ? strdup(typ->ty_type) : 0;
1102 	return (1);
1103 }
1104 
1105 /*
1106  * Walk the list of ttys and create sessions for each active line.
1107  */
1108 static state_func_t
1109 read_ttys(void)
1110 {
1111 	int session_index = 0;
1112 	session_t *sp, *snext;
1113 	struct ttyent *typ;
1114 
1115 	/*
1116 	 * Destroy any previous session state.
1117 	 * There shouldn't be any, but just in case...
1118 	 */
1119 	for (sp = sessions; sp; sp = snext) {
1120 		if (sp->se_process)
1121 			clear_session_logs(sp);
1122 		snext = sp->se_next;
1123 		free_session(sp);
1124 	}
1125 	sessions = 0;
1126 	if (start_session_db())
1127 		return (state_func_t) single_user;
1128 
1129 	/*
1130 	 * Allocate a session entry for each active port.
1131 	 * Note that sp starts at 0.
1132 	 */
1133 	while ((typ = getttyent()) != NULL)
1134 		if ((snext = new_session(sp, ++session_index, typ)) != NULL)
1135 			sp = snext;
1136 
1137 	endttyent();
1138 
1139 	return (state_func_t) multi_user;
1140 }
1141 
1142 /*
1143  * Start a window system running.
1144  */
1145 static void
1146 start_window_system(session_t *sp)
1147 {
1148 	pid_t pid;
1149 	sigset_t mask;
1150 	char term[64], *env[2];
1151 	int status;
1152 
1153 	if ((pid = fork()) == -1) {
1154 		emergency("can't fork for window system on port %s: %m",
1155 		    sp->se_device);
1156 		/* hope that getty fails and we can try again */
1157 		return;
1158 	}
1159 	if (pid) {
1160 		waitpid(-1, &status, 0);
1161 		return;
1162 	}
1163 
1164 	/* reparent window process to the init to not make a zombie on exit */
1165 	if ((pid = fork()) == -1) {
1166 		emergency("can't fork for window system on port %s: %m",
1167 		    sp->se_device);
1168 		_exit(1);
1169 	}
1170 	if (pid)
1171 		_exit(0);
1172 
1173 	sigemptyset(&mask);
1174 	sigprocmask(SIG_SETMASK, &mask, (sigset_t *) 0);
1175 
1176 	if (setsid() < 0)
1177 		emergency("setsid failed (window) %m");
1178 
1179 #ifdef LOGIN_CAP
1180 	setprocresources(RESOURCE_WINDOW);
1181 #endif
1182 	if (sp->se_type) {
1183 		/* Don't use malloc after fork */
1184 		strcpy(term, "TERM=");
1185 		strncat(term, sp->se_type, sizeof(term) - 6);
1186 		env[0] = term;
1187 		env[1] = 0;
1188 	}
1189 	else
1190 		env[0] = 0;
1191 	execve(sp->se_window_argv[0], sp->se_window_argv, env);
1192 	stall("can't exec window system '%s' for port %s: %m",
1193 		sp->se_window_argv[0], sp->se_device);
1194 	_exit(1);
1195 }
1196 
1197 /*
1198  * Start a login session running.
1199  */
1200 static pid_t
1201 start_getty(session_t *sp)
1202 {
1203 	pid_t pid;
1204 	sigset_t mask;
1205 	time_t current_time = time((time_t *) 0);
1206 	int too_quick = 0;
1207 	char term[64], *env[2];
1208 
1209 	if (current_time >= sp->se_started &&
1210 	    current_time - sp->se_started < GETTY_SPACING) {
1211 		if (++sp->se_nspace > GETTY_NSPACE) {
1212 			sp->se_nspace = 0;
1213 			too_quick = 1;
1214 		}
1215 	} else
1216 		sp->se_nspace = 0;
1217 
1218 	/*
1219 	 * fork(), not vfork() -- we can't afford to block.
1220 	 */
1221 	if ((pid = fork()) == -1) {
1222 		emergency("can't fork for getty on port %s: %m", sp->se_device);
1223 		return -1;
1224 	}
1225 
1226 	if (pid)
1227 		return pid;
1228 
1229 	if (too_quick) {
1230 		warning("getty repeating too quickly on port %s, sleeping %d secs",
1231 		    sp->se_device, GETTY_SLEEP);
1232 		sleep((unsigned) GETTY_SLEEP);
1233 	}
1234 
1235 	if (sp->se_window) {
1236 		start_window_system(sp);
1237 		sleep(WINDOW_WAIT);
1238 	}
1239 
1240 	sigemptyset(&mask);
1241 	sigprocmask(SIG_SETMASK, &mask, (sigset_t *) 0);
1242 
1243 #ifdef LOGIN_CAP
1244 	setprocresources(RESOURCE_GETTY);
1245 #endif
1246 	if (sp->se_type) {
1247 		/* Don't use malloc after fork */
1248 		strcpy(term, "TERM=");
1249 		strncat(term, sp->se_type, sizeof(term) - 6);
1250 		env[0] = term;
1251 		env[1] = 0;
1252 	} else
1253 		env[0] = 0;
1254 	execve(sp->se_getty_argv[0], sp->se_getty_argv, env);
1255 	stall("can't exec getty '%s' for port %s: %m",
1256 		sp->se_getty_argv[0], sp->se_device);
1257 	_exit(1);
1258 }
1259 
1260 /*
1261  * Collect exit status for a child.
1262  * If an exiting login, start a new login running.
1263  */
1264 static void
1265 collect_child(pid_t pid)
1266 {
1267 	session_t *sp, *sprev, *snext;
1268 
1269 	if (! sessions)
1270 		return;
1271 
1272 	if (! (sp = find_session(pid)))
1273 		return;
1274 
1275 	clear_session_logs(sp);
1276 	del_session(sp);
1277 	sp->se_process = 0;
1278 
1279 	if (sp->se_flags & SE_SHUTDOWN) {
1280 		if ((sprev = sp->se_prev) != NULL)
1281 			sprev->se_next = sp->se_next;
1282 		else
1283 			sessions = sp->se_next;
1284 		if ((snext = sp->se_next) != NULL)
1285 			snext->se_prev = sp->se_prev;
1286 		free_session(sp);
1287 		return;
1288 	}
1289 
1290 	if ((pid = start_getty(sp)) == -1) {
1291 		/* serious trouble */
1292 		requested_transition = clean_ttys;
1293 		return;
1294 	}
1295 
1296 	sp->se_process = pid;
1297 	sp->se_started = time((time_t *) 0);
1298 	add_session(sp);
1299 }
1300 
1301 /*
1302  * Catch a signal and request a state transition.
1303  */
1304 static void
1305 transition_handler(int sig)
1306 {
1307 
1308 	switch (sig) {
1309 	case SIGHUP:
1310 		requested_transition = clean_ttys;
1311 		break;
1312 	case SIGUSR2:
1313 		howto = RB_POWEROFF;
1314 	case SIGUSR1:
1315 		howto |= RB_HALT;
1316 	case SIGINT:
1317 		Reboot = TRUE;
1318 	case SIGTERM:
1319 		requested_transition = death;
1320 		break;
1321 	case SIGTSTP:
1322 		requested_transition = catatonia;
1323 		break;
1324 	default:
1325 		requested_transition = 0;
1326 		break;
1327 	}
1328 }
1329 
1330 /*
1331  * Take the system multiuser.
1332  */
1333 static state_func_t
1334 multi_user(void)
1335 {
1336 	pid_t pid;
1337 	session_t *sp;
1338 
1339 	requested_transition = 0;
1340 
1341 	/*
1342 	 * If the administrator has not set the security level to -1
1343 	 * to indicate that the kernel should not run multiuser in secure
1344 	 * mode, and the run script has not set a higher level of security
1345 	 * than level 1, then put the kernel into secure mode.
1346 	 */
1347 	if (getsecuritylevel() == 0)
1348 		setsecuritylevel(1);
1349 
1350 	for (sp = sessions; sp; sp = sp->se_next) {
1351 		if (sp->se_process)
1352 			continue;
1353 		if ((pid = start_getty(sp)) == -1) {
1354 			/* serious trouble */
1355 			requested_transition = clean_ttys;
1356 			break;
1357 		}
1358 		sp->se_process = pid;
1359 		sp->se_started = time((time_t *) 0);
1360 		add_session(sp);
1361 	}
1362 
1363 	while (!requested_transition)
1364 		if ((pid = waitpid(-1, (int *) 0, 0)) != -1)
1365 			collect_child(pid);
1366 
1367 	return (state_func_t) requested_transition;
1368 }
1369 
1370 /*
1371  * This is an (n*2)+(n^2) algorithm.  We hope it isn't run often...
1372  */
1373 static state_func_t
1374 clean_ttys(void)
1375 {
1376 	session_t *sp, *sprev;
1377 	struct ttyent *typ;
1378 	int session_index = 0;
1379 	int devlen;
1380 	char *old_getty, *old_window, *old_type;
1381 
1382 	/*
1383 	 * mark all sessions for death, (!SE_PRESENT)
1384 	 * as we find or create new ones they'll be marked as keepers,
1385 	 * we'll later nuke all the ones not found in /etc/ttys
1386 	 */
1387 	for (sp = sessions; sp != NULL; sp = sp->se_next)
1388 		sp->se_flags &= ~SE_PRESENT;
1389 
1390 	devlen = sizeof(_PATH_DEV) - 1;
1391 	while ((typ = getttyent()) != NULL) {
1392 		++session_index;
1393 
1394 		for (sprev = 0, sp = sessions; sp; sprev = sp, sp = sp->se_next)
1395 			if (strcmp(typ->ty_name, sp->se_device + devlen) == 0)
1396 				break;
1397 
1398 		if (sp) {
1399 			/* we want this one to live */
1400 			sp->se_flags |= SE_PRESENT;
1401 			if (sp->se_index != session_index) {
1402 				warning("port %s changed utmp index from %d to %d",
1403 				       sp->se_device, sp->se_index,
1404 				       session_index);
1405 				sp->se_index = session_index;
1406 			}
1407 			if ((typ->ty_status & TTY_ON) == 0 ||
1408 			    typ->ty_getty == 0) {
1409 				sp->se_flags |= SE_SHUTDOWN;
1410 				kill(sp->se_process, SIGHUP);
1411 				continue;
1412 			}
1413 			sp->se_flags &= ~SE_SHUTDOWN;
1414 			old_getty = sp->se_getty ? strdup(sp->se_getty) : 0;
1415 			old_window = sp->se_window ? strdup(sp->se_window) : 0;
1416 			old_type = sp->se_type ? strdup(sp->se_type) : 0;
1417 			if (setupargv(sp, typ) == 0) {
1418 				warning("can't parse getty for port %s",
1419 					sp->se_device);
1420 				sp->se_flags |= SE_SHUTDOWN;
1421 				kill(sp->se_process, SIGHUP);
1422 			}
1423 			else if (   !old_getty
1424 				 || (!old_type && sp->se_type)
1425 				 || (old_type && !sp->se_type)
1426 				 || (!old_window && sp->se_window)
1427 				 || (old_window && !sp->se_window)
1428 				 || (strcmp(old_getty, sp->se_getty) != 0)
1429 				 || (old_window && strcmp(old_window, sp->se_window) != 0)
1430 				 || (old_type && strcmp(old_type, sp->se_type) != 0)
1431 				) {
1432 				/* Don't set SE_SHUTDOWN here */
1433 				sp->se_nspace = 0;
1434 				sp->se_started = 0;
1435 				kill(sp->se_process, SIGHUP);
1436 			}
1437 			if (old_getty)
1438 				free(old_getty);
1439 			if (old_window)
1440 				free(old_window);
1441 			if (old_type)
1442 				free(old_type);
1443 			continue;
1444 		}
1445 
1446 		new_session(sprev, session_index, typ);
1447 	}
1448 
1449 	endttyent();
1450 
1451 	/*
1452 	 * sweep through and kill all deleted sessions
1453 	 * ones who's /etc/ttys line was deleted (SE_PRESENT unset)
1454 	 */
1455 	for (sp = sessions; sp != NULL; sp = sp->se_next) {
1456 		if ((sp->se_flags & SE_PRESENT) == 0) {
1457 			sp->se_flags |= SE_SHUTDOWN;
1458 			kill(sp->se_process, SIGHUP);
1459 		}
1460 	}
1461 
1462 	return (state_func_t) multi_user;
1463 }
1464 
1465 /*
1466  * Block further logins.
1467  */
1468 static state_func_t
1469 catatonia(void)
1470 {
1471 	session_t *sp;
1472 
1473 	for (sp = sessions; sp; sp = sp->se_next)
1474 		sp->se_flags |= SE_SHUTDOWN;
1475 
1476 	return (state_func_t) multi_user;
1477 }
1478 
1479 /*
1480  * Note SIGALRM.
1481  */
1482 static void
1483 alrm_handler(int sig)
1484 {
1485 
1486 	(void)sig;
1487 	clang = 1;
1488 }
1489 
1490 /*
1491  * Bring the system down to single user.
1492  */
1493 static state_func_t
1494 death(void)
1495 {
1496 	struct utmpx utx;
1497 	session_t *sp;
1498 	int i;
1499 	pid_t pid;
1500 	static const int death_sigs[2] = { SIGTERM, SIGKILL };
1501 
1502 	/* NB: should send a message to the session logger to avoid blocking. */
1503 	utx.ut_type = SHUTDOWN_TIME;
1504 	gettimeofday(&utx.ut_tv, NULL);
1505 	pututxline(&utx);
1506 
1507 	/*
1508 	 * Also revoke the TTY here.  Because runshutdown() may reopen
1509 	 * the TTY whose getty we're killing here, there is no guarantee
1510 	 * runshutdown() will perform the initial open() call, causing
1511 	 * the terminal attributes to be misconfigured.
1512 	 */
1513 	for (sp = sessions; sp; sp = sp->se_next) {
1514 		sp->se_flags |= SE_SHUTDOWN;
1515 		kill(sp->se_process, SIGHUP);
1516 		revoke(sp->se_device);
1517 	}
1518 
1519 	/* Try to run the rc.shutdown script within a period of time */
1520 	runshutdown();
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 		setctty(_PATH_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_close(lc);
1722 	}
1723 }
1724 #endif
1725