xref: /netbsd-src/sbin/init/init.c (revision b1c86f5f087524e68db12794ee9c3e3da1ab17a0)
1 /*	$NetBSD: init.c,v 1.100 2009/12/29 17:07:17 elad Exp $	*/
2 
3 /*-
4  * Copyright (c) 1991, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * This code is derived from software contributed to Berkeley by
8  * Donn Seeley at Berkeley Software Design, Inc.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 
35 #include <sys/cdefs.h>
36 #ifndef lint
37 __COPYRIGHT("@(#) Copyright (c) 1991, 1993\
38  The Regents of the University of California.  All rights reserved.");
39 #endif /* not lint */
40 
41 #ifndef lint
42 #if 0
43 static char sccsid[] = "@(#)init.c	8.2 (Berkeley) 4/28/95";
44 #else
45 __RCSID("$NetBSD: init.c,v 1.100 2009/12/29 17:07:17 elad Exp $");
46 #endif
47 #endif /* not lint */
48 
49 #include <sys/param.h>
50 #include <sys/sysctl.h>
51 #include <sys/wait.h>
52 #include <sys/mman.h>
53 #include <sys/stat.h>
54 #include <sys/mount.h>
55 #include <machine/cpu.h>
56 
57 #include <db.h>
58 #include <errno.h>
59 #include <fcntl.h>
60 #include <signal.h>
61 #include <stdio.h>
62 #include <stdlib.h>
63 #include <string.h>
64 #include <syslog.h>
65 #include <time.h>
66 #include <ttyent.h>
67 #include <unistd.h>
68 #include <util.h>
69 #include <paths.h>
70 #include <err.h>
71 
72 #include <stdarg.h>
73 
74 #ifdef SECURE
75 #include <pwd.h>
76 #endif
77 
78 #include "pathnames.h"
79 
80 #define XSTR(x) #x
81 #define STR(x) XSTR(x)
82 
83 /*
84  * Sleep times; used to prevent thrashing.
85  */
86 #define	GETTY_SPACING		 5	/* N secs minimum getty spacing */
87 #define	GETTY_SLEEP		30	/* sleep N secs after spacing problem */
88 #define	WINDOW_WAIT		 3	/* wait N secs after starting window */
89 #define	STALL_TIMEOUT		30	/* wait N secs after warning */
90 #define	DEATH_WATCH		10	/* wait N secs for procs to die */
91 
92 const struct timespec dtrtime = {.tv_sec = 0, .tv_nsec = 250000};
93 
94 #if defined(RESCUEDIR)
95 #define	INIT_BSHELL	RESCUEDIR "/sh"
96 #define	INIT_MOUNT_MFS	RESCUEDIR "/mount_mfs"
97 #define	INIT_PATH	RESCUEDIR ":" _PATH_STDPATH
98 #else
99 #define	INIT_BSHELL	_PATH_BSHELL
100 #define	INIT_MOUNT_MFS	"/sbin/mount_mfs"
101 #define	INIT_PATH	_PATH_STDPATH
102 #endif
103 
104 int main(int, char *[]);
105 
106 void handle(sig_t, ...);
107 void delset(sigset_t *, ...);
108 
109 void stall(const char *, ...)
110     __attribute__((__format__(__printf__,1,2)));
111 void warning(const char *, ...)
112     __attribute__((__format__(__printf__,1,2)));
113 void emergency(const char *, ...)
114     __attribute__((__format__(__printf__,1,2)));
115 void disaster(int);
116 void badsys(int);
117 
118 /*
119  * We really need a recursive typedef...
120  * The following at least guarantees that the return type of (*state_t)()
121  * is sufficiently wide to hold a function pointer.
122  */
123 typedef long (*state_func_t)(void);
124 typedef state_func_t (*state_t)(void);
125 
126 #define	DEATH		'd'
127 #define	SINGLE_USER	's'
128 #define	RUNCOM		'r'
129 #define	READ_TTYS	't'
130 #define	MULTI_USER	'm'
131 #define	CLEAN_TTYS	'T'
132 #define	CATATONIA	'c'
133 
134 state_func_t single_user(void);
135 state_func_t runcom(void);
136 state_func_t read_ttys(void);
137 state_func_t multi_user(void);
138 state_func_t clean_ttys(void);
139 state_func_t catatonia(void);
140 state_func_t death(void);
141 
142 enum { AUTOBOOT, FASTBOOT } runcom_mode = AUTOBOOT;
143 
144 void transition(state_t);
145 void setctty(const char *);
146 
147 typedef struct init_session {
148 	int	se_index;		/* index of entry in ttys file */
149 	pid_t	se_process;		/* controlling process */
150 	struct timeval	se_started;	/* used to avoid thrashing */
151 	int	se_flags;		/* status of session */
152 #define	SE_SHUTDOWN	0x1		/* session won't be restarted */
153 #define	SE_PRESENT	0x2		/* session is in /etc/ttys */
154 	char	*se_device;		/* filename of port */
155 	char	*se_getty;		/* what to run on that port */
156 	char	**se_getty_argv;	/* pre-parsed argument array */
157 	char	*se_window;		/* window system (started only once) */
158 	char	**se_window_argv;	/* pre-parsed argument array */
159 	struct	init_session *se_prev;
160 	struct	init_session *se_next;
161 } session_t;
162 
163 void free_session(session_t *);
164 session_t *new_session(session_t *, int, struct ttyent *);
165 session_t *sessions;
166 
167 char **construct_argv(char *);
168 void start_window_system(session_t *);
169 void collect_child(pid_t, int);
170 pid_t start_getty(session_t *);
171 void transition_handler(int);
172 void alrm_handler(int);
173 int has_securelevel(void);
174 void setsecuritylevel(int);
175 int getsecuritylevel(void);
176 int securelevel_present;
177 int setupargv(session_t *, struct ttyent *);
178 int clang;
179 
180 int start_session_db(void);
181 void add_session(session_t *);
182 void del_session(session_t *);
183 session_t *find_session(pid_t);
184 DB *session_db;
185 
186 int do_setttyent(void);
187 
188 #ifndef LETS_GET_SMALL
189 state_t requested_transition = runcom;
190 
191 void clear_session_logs(session_t *, int);
192 state_func_t runetcrc(int);
193 #ifdef SUPPORT_UTMPX
194 static struct timeval boot_time;
195 state_t current_state = death;
196 static void session_utmpx(const session_t *, int);
197 static void make_utmpx(const char *, const char *, int, pid_t,
198     const struct timeval *, int);
199 static char get_runlevel(const state_t);
200 static void utmpx_set_runlevel(char, char);
201 #endif
202 
203 #ifdef CHROOT
204 int did_multiuser_chroot = 0;
205 char rootdir[PATH_MAX];
206 int shouldchroot(void);
207 int createsysctlnode(void);
208 #endif /* CHROOT */
209 
210 #else /* LETS_GET_SMALL */
211 state_t requested_transition = single_user;
212 #endif /* !LETS_GET_SMALL */
213 
214 #ifdef MFS_DEV_IF_NO_CONSOLE
215 
216 static int mfs_dev(void);
217 
218 #endif
219 
220 /*
221  * The mother of all processes.
222  */
223 int
224 main(int argc, char **argv)
225 {
226 	struct sigaction sa;
227 	sigset_t mask;
228 #ifndef LETS_GET_SMALL
229 	int c;
230 
231 #ifdef SUPPORT_UTMPX
232 	(void)gettimeofday(&boot_time, NULL);
233 #endif /* SUPPORT_UTMPX */
234 
235 	/* Dispose of random users. */
236 	if (getuid() != 0) {
237 		errno = EPERM;
238 		err(1, NULL);
239 	}
240 
241 	/* System V users like to reexec init. */
242 	if (getpid() != 1)
243 		errx(1, "already running");
244 #endif
245 
246 	/*
247 	 * Create an initial session.
248 	 */
249 	if (setsid() < 0)
250 		warn("initial setsid() failed");
251 
252 	/*
253 	 * Establish an initial user so that programs running
254 	 * single user do not freak out and die (like passwd).
255 	 */
256 	if (setlogin("root") < 0)
257 		warn("setlogin() failed");
258 
259 
260 #ifdef MFS_DEV_IF_NO_CONSOLE
261 	if (mfs_dev() == -1)
262 		requested_transition = single_user;
263 #endif
264 
265 #ifndef LETS_GET_SMALL
266 	/*
267 	 * Note that this does NOT open a file...
268 	 * Does 'init' deserve its own facility number?
269 	 */
270 	openlog("init", LOG_CONS, LOG_AUTH);
271 #endif /* LETS_GET_SMALL */
272 
273 
274 #ifndef LETS_GET_SMALL
275 	/*
276 	 * This code assumes that we always get arguments through flags,
277 	 * never through bits set in some random machine register.
278 	 */
279 	while ((c = getopt(argc, argv, "sf")) != -1)
280 		switch (c) {
281 		case 's':
282 			requested_transition = single_user;
283 			break;
284 		case 'f':
285 			runcom_mode = FASTBOOT;
286 			break;
287 		default:
288 			warning("unrecognized flag `%c'", c);
289 			break;
290 		}
291 
292 	if (optind != argc)
293 		warning("ignoring excess arguments");
294 #else /* LETS_GET_SMALL */
295 	requested_transition = single_user;
296 #endif /* LETS_GET_SMALL */
297 
298 	/*
299 	 * We catch or block signals rather than ignore them,
300 	 * so that they get reset on exec.
301 	 */
302 	handle(badsys, SIGSYS, 0);
303 	handle(disaster, SIGABRT, SIGFPE, SIGILL, SIGSEGV,
304 	       SIGBUS, SIGXCPU, SIGXFSZ, 0);
305 	handle(transition_handler, SIGHUP, SIGTERM, SIGTSTP, 0);
306 	handle(alrm_handler, SIGALRM, 0);
307 	(void)sigfillset(&mask);
308 	delset(&mask, SIGABRT, SIGFPE, SIGILL, SIGSEGV, SIGBUS, SIGSYS,
309 	    SIGXCPU, SIGXFSZ, SIGHUP, SIGTERM, SIGTSTP, SIGALRM, 0);
310 	(void)sigprocmask(SIG_SETMASK, &mask, NULL);
311 	(void)sigemptyset(&sa.sa_mask);
312 	sa.sa_flags = 0;
313 	sa.sa_handler = SIG_IGN;
314 	(void)sigaction(SIGTTIN, &sa, NULL);
315 	(void)sigaction(SIGTTOU, &sa, NULL);
316 
317 	/*
318 	 * Paranoia.
319 	 */
320 	(void)close(0);
321 	(void)close(1);
322 	(void)close(2);
323 
324 #if !defined(LETS_GET_SMALL) && defined(CHROOT)
325 	/* Create "init.root" sysctl node. */
326 	(void)createsysctlnode();
327 #endif /* !LETS_GET_SMALL && CHROOT*/
328 
329 	/*
330 	 * Securelevel might not be supported by the kernel. Query for it, and
331 	 * set a variable indicating whether we should attempt anything with it
332 	 * or not.
333 	 */
334 	securelevel_present = has_securelevel();
335 
336 	/*
337 	 * Start the state machine.
338 	 */
339 	transition(requested_transition);
340 
341 	/*
342 	 * Should never reach here.
343 	 */
344 	return 1;
345 }
346 
347 /*
348  * Associate a function with a signal handler.
349  */
350 void
351 handle(sig_t handler, ...)
352 {
353 	int sig;
354 	struct sigaction sa;
355 	sigset_t mask_everything;
356 	va_list ap;
357 
358 	va_start(ap, handler);
359 
360 	sa.sa_handler = handler;
361 	(void)sigfillset(&mask_everything);
362 
363 	while ((sig = va_arg(ap, int)) != 0) {
364 		sa.sa_mask = mask_everything;
365 		/* XXX SA_RESTART? */
366 		sa.sa_flags = sig == SIGCHLD ? SA_NOCLDSTOP : 0;
367 		(void)sigaction(sig, &sa, NULL);
368 	}
369 	va_end(ap);
370 }
371 
372 /*
373  * Delete a set of signals from a mask.
374  */
375 void
376 delset(sigset_t *maskp, ...)
377 {
378 	int sig;
379 	va_list ap;
380 
381 	va_start(ap, maskp);
382 
383 	while ((sig = va_arg(ap, int)) != 0)
384 		(void)sigdelset(maskp, sig);
385 	va_end(ap);
386 }
387 
388 #if 0	/* Enable to get error messages from init ! */
389 #define vsyslog(level, fmt, ap) print_console(level, fmt, ap)
390 #define closelog()
391 
392 static void
393 print_console(int level, const char *message, va_list ap)
394 {
395 	/*
396 	 * XXX: syslog seems to just plain not work in console-only
397 	 * XXX: situation... that should be fixed.  Let's leave this
398 	 * XXX: note + code here in case someone gets in trouble and
399 	 * XXX: wants to debug. -- Jachym Holecek <freza@liberouter.org>
400 	 */
401 	char errbuf[1024];
402 	int fd, len;
403 
404 	/* We can't do anything on errors, anyway... */
405 	fd = open(_PATH_CONSOLE, O_WRONLY);
406 	if (fd == -1)
407 		return ;
408 
409 	/* %m will get lost... */
410 	len = vsnprintf(errbuf, sizeof(errbuf), message, ap);
411 	(void)write(fd, (void *)errbuf, len);
412 	(void)close(fd);
413 }
414 #endif
415 
416 /*
417  * Log a message and sleep for a while (to give someone an opportunity
418  * to read it and to save log or hardcopy output if the problem is chronic).
419  * NB: should send a message to the session logger to avoid blocking.
420  */
421 void
422 stall(const char *message, ...)
423 {
424 	va_list ap;
425 
426 	va_start(ap, message);
427 	vsyslog(LOG_ALERT, message, ap);
428 	va_end(ap);
429 	closelog();
430 	(void)sleep(STALL_TIMEOUT);
431 }
432 
433 /*
434  * Like stall(), but doesn't sleep.
435  * If cpp had variadic macros, the two functions could be #defines for another.
436  * NB: should send a message to the session logger to avoid blocking.
437  */
438 void
439 warning(const char *message, ...)
440 {
441 	va_list ap;
442 
443 	va_start(ap, message);
444 	vsyslog(LOG_ALERT, message, ap);
445 	va_end(ap);
446 	closelog();
447 }
448 
449 /*
450  * Log an emergency message.
451  * NB: should send a message to the session logger to avoid blocking.
452  */
453 void
454 emergency(const char *message, ...)
455 {
456 	va_list ap;
457 
458 	va_start(ap, message);
459 	vsyslog(LOG_EMERG, message, ap);
460 	va_end(ap);
461 	closelog();
462 }
463 
464 /*
465  * Catch a SIGSYS signal.
466  *
467  * These may arise if a system does not support sysctl.
468  * We tolerate up to 25 of these, then throw in the towel.
469  */
470 void
471 badsys(int sig)
472 {
473 	static int badcount = 0;
474 
475 	if (badcount++ < 25)
476 		return;
477 	disaster(sig);
478 }
479 
480 /*
481  * Catch an unexpected signal.
482  */
483 void
484 disaster(int sig)
485 {
486 
487 	emergency("fatal signal: %s", strsignal(sig));
488 	(void)sleep(STALL_TIMEOUT);
489 	_exit(sig);		/* reboot */
490 }
491 
492 /*
493  * Check if securelevel is present.
494  */
495 int
496 has_securelevel(void)
497 {
498 #ifdef KERN_SECURELVL
499 	int name[2], curlevel;
500 	size_t len;
501 
502 	name[0] = CTL_KERN;
503 	name[1] = KERN_SECURELVL;
504 	len = sizeof curlevel;
505 	if (sysctl(name, 2, &curlevel, &len, NULL, 0) == -1) {
506 		/* If it doesn't exist, it's okay. */
507 		if (errno == ENOENT)
508 			return 0;
509 	}
510 	return 1;
511 #else
512 	return 0;
513 #endif
514 }
515 
516 /*
517  * Get the security level of the kernel.
518  */
519 int
520 getsecuritylevel(void)
521 {
522 #ifdef KERN_SECURELVL
523 	int name[2], curlevel;
524 	size_t len;
525 
526 	if (!securelevel_present)
527 		return -1;
528 
529 	name[0] = CTL_KERN;
530 	name[1] = KERN_SECURELVL;
531 	len = sizeof curlevel;
532 	if (sysctl(name, 2, &curlevel, &len, NULL, 0) == -1) {
533 		emergency("cannot get kernel security level: %m");
534 		return -1;
535 	}
536 	return curlevel;
537 #else
538 	return -1;
539 #endif
540 }
541 
542 /*
543  * Set the security level of the kernel.
544  */
545 void
546 setsecuritylevel(int newlevel)
547 {
548 #ifdef KERN_SECURELVL
549 	int name[2], curlevel;
550 
551 	if (!securelevel_present)
552 		return;
553 
554 	curlevel = getsecuritylevel();
555 	if (newlevel == curlevel)
556 		return;
557 	name[0] = CTL_KERN;
558 	name[1] = KERN_SECURELVL;
559 	if (sysctl(name, 2, NULL, NULL, &newlevel, sizeof newlevel) == -1) {
560 		emergency("cannot change kernel security level from"
561 		    " %d to %d: %m", curlevel, newlevel);
562 		return;
563 	}
564 #ifdef SECURE
565 	warning("kernel security level changed from %d to %d",
566 	    curlevel, newlevel);
567 #endif
568 #endif
569 }
570 
571 /*
572  * Change states in the finite state machine.
573  * The initial state is passed as an argument.
574  */
575 void
576 transition(state_t s)
577 {
578 
579 	if (s == NULL)
580 		return;
581 	for (;;) {
582 #ifdef SUPPORT_UTMPX
583 #ifndef LETS_GET_SMALL
584 		utmpx_set_runlevel(get_runlevel(current_state),
585 		    get_runlevel(s));
586 		current_state = s;
587 #endif
588 #endif
589 		s = (state_t)(*s)();
590 	}
591 }
592 
593 #ifndef LETS_GET_SMALL
594 /*
595  * Close out the accounting files for a login session.
596  * NB: should send a message to the session logger to avoid blocking.
597  */
598 void
599 clear_session_logs(session_t *sp, int status)
600 {
601 #if defined(SUPPORT_UTMP) || defined(SUPPORT_UTMPX)
602 	char *line = sp->se_device + sizeof(_PATH_DEV) - 1;
603 #endif
604 
605 #ifdef SUPPORT_UTMPX
606 	if (logoutx(line, status, DEAD_PROCESS))
607 		logwtmpx(line, "", "", status, DEAD_PROCESS);
608 #endif
609 #ifdef SUPPORT_UTMP
610 	if (logout(line))
611 		logwtmp(line, "", "");
612 #endif
613 }
614 #endif
615 
616 /*
617  * Start a session and allocate a controlling terminal.
618  * Only called by children of init after forking.
619  */
620 void
621 setctty(const char *name)
622 {
623 	int fd;
624 
625 	(void)revoke(name);
626 	(void)nanosleep(&dtrtime, NULL);	/* leave DTR low for a bit */
627 	if ((fd = open(name, O_RDWR)) == -1) {
628 		stall("can't open %s: %m", name);
629 		_exit(1);
630 	}
631 	if (login_tty(fd) == -1) {
632 		stall("can't get %s for controlling terminal: %m", name);
633 		_exit(2);
634 	}
635 }
636 
637 /*
638  * Bring the system up single user.
639  */
640 state_func_t
641 single_user(void)
642 {
643 	pid_t pid, wpid;
644 	int status;
645 	int from_securitylevel;
646 	sigset_t mask;
647 	struct sigaction sa, satstp, sahup;
648 #ifdef ALTSHELL
649 	const char *shell = INIT_BSHELL;
650 #endif
651 	const char *argv[2];
652 #ifdef SECURE
653 	struct ttyent *typ;
654 	struct passwd *pp;
655 	char *clear, *password;
656 #endif
657 #ifdef ALTSHELL
658 	char altshell[128];
659 #endif /* ALTSHELL */
660 
661 #if !defined(LETS_GET_SMALL) && defined(CHROOT)
662 	/* Clear previous idea, just in case. */
663 	did_multiuser_chroot = 0;
664 #endif /* !LETS_GET_SMALL && CHROOT */
665 
666 	/*
667 	 * If the kernel is in secure mode, downgrade it to insecure mode.
668 	 */
669 	from_securitylevel = getsecuritylevel();
670 	if (from_securitylevel > 0)
671 		setsecuritylevel(0);
672 
673 	(void)sigemptyset(&sa.sa_mask);
674 	sa.sa_flags = 0;
675 	sa.sa_handler = SIG_IGN;
676 	(void)sigaction(SIGTSTP, &sa, &satstp);
677 	(void)sigaction(SIGHUP, &sa, &sahup);
678 	if ((pid = fork()) == 0) {
679 		/*
680 		 * Start the single user session.
681 		 */
682 		if (access(_PATH_CONSTTY, F_OK) == 0)
683 			setctty(_PATH_CONSTTY);
684 		else
685 			setctty(_PATH_CONSOLE);
686 
687 #ifdef SECURE
688 		/*
689 		 * Check the root password.
690 		 * We don't care if the console is 'on' by default;
691 		 * it's the only tty that can be 'off' and 'secure'.
692 		 */
693 		typ = getttynam("console");
694 		pp = getpwnam("root");
695 		if (typ && (from_securitylevel >=2 || (typ->ty_status
696 		    & TTY_SECURE) == 0) && pp && *pp->pw_passwd != '\0') {
697 			(void)fprintf(stderr,
698 			    "Enter root password, or ^D to go multi-user\n");
699 			for (;;) {
700 				clear = getpass("Password:");
701 				if (clear == 0 || *clear == '\0')
702 					_exit(0);
703 				password = crypt(clear, pp->pw_passwd);
704 				(void)memset(clear, 0, _PASSWORD_LEN);
705 				if (strcmp(password, pp->pw_passwd) == 0)
706 					break;
707 				warning("single-user login failed");
708 			}
709 		}
710 		(void)endttyent();
711 		endpwent();
712 #endif /* SECURE */
713 
714 #ifdef ALTSHELL
715 		(void)fprintf(stderr,
716 		    "Enter pathname of shell or RETURN for %s: ", shell);
717 		if (fgets(altshell, sizeof(altshell), stdin) == NULL) {
718 			altshell[0] = '\0';
719 		} else {
720 			/* nuke \n */
721 			char *p;
722 
723 			if ((p = strchr(altshell, '\n')) != NULL)
724 				*p = '\0';
725 		}
726 
727 		if (altshell[0])
728 			shell = altshell;
729 #endif /* ALTSHELL */
730 
731 		/*
732 		 * Unblock signals.
733 		 * We catch all the interesting ones,
734 		 * and those are reset to SIG_DFL on exec.
735 		 */
736 		(void)sigemptyset(&mask);
737 		(void)sigprocmask(SIG_SETMASK, &mask, NULL);
738 
739 		/*
740 		 * Fire off a shell.
741 		 * If the default one doesn't work, try the Bourne shell.
742 		 */
743 		argv[0] = "-sh";
744 		argv[1] = 0;
745 		(void)setenv("PATH", INIT_PATH, 1);
746 #ifdef ALTSHELL
747 		if (altshell[0])
748 			argv[0] = altshell;
749 		(void)execv(shell, __UNCONST(argv));
750 		emergency("can't exec `%s' for single user: %m", shell);
751 		argv[0] = "-sh";
752 #endif /* ALTSHELL */
753 		(void)execv(INIT_BSHELL, __UNCONST(argv));
754 		emergency("can't exec `%s' for single user: %m", INIT_BSHELL);
755 		(void)sleep(STALL_TIMEOUT);
756 		_exit(3);
757 	}
758 
759 	if (pid == -1) {
760 		/*
761 		 * We are seriously hosed.  Do our best.
762 		 */
763 		emergency("can't fork single-user shell: %m, trying again");
764 		while (waitpid(-1, NULL, WNOHANG) > 0)
765 			continue;
766 		(void)sigaction(SIGTSTP, &satstp, NULL);
767 		(void)sigaction(SIGHUP, &sahup, NULL);
768 		return (state_func_t)single_user;
769 	}
770 
771 	requested_transition = 0;
772 	do {
773 		if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1)
774 			collect_child(wpid, status);
775 		if (wpid == -1) {
776 			if (errno == EINTR)
777 				continue;
778 			warning("wait for single-user shell failed: %m; "
779 			    "restarting");
780 			return (state_func_t)single_user;
781 		}
782 		if (wpid == pid && WIFSTOPPED(status)) {
783 			warning("shell stopped, restarting");
784 			(void)kill(pid, SIGCONT);
785 			wpid = -1;
786 		}
787 	} while (wpid != pid && !requested_transition);
788 
789 	if (requested_transition) {
790 		(void)sigaction(SIGTSTP, &satstp, NULL);
791 		(void)sigaction(SIGHUP, &sahup, NULL);
792 		return (state_func_t)requested_transition;
793 	}
794 
795 	if (WIFSIGNALED(status)) {
796 		if (WTERMSIG(status) == SIGKILL) {
797 			/* executed /sbin/reboot; wait for the end quietly */
798 			sigset_t s;
799 
800 			(void)sigfillset(&s);
801 			for (;;)
802 				(void)sigsuspend(&s);
803 		} else {
804 			warning("single user shell terminated (%x), restarting",
805 				status);
806 			(void)sigaction(SIGTSTP, &satstp, NULL);
807 			(void)sigaction(SIGHUP, &sahup, NULL);
808 			return (state_func_t)single_user;
809 		}
810 	}
811 
812 	runcom_mode = FASTBOOT;
813 	(void)sigaction(SIGTSTP, &satstp, NULL);
814 	(void)sigaction(SIGHUP, &sahup, NULL);
815 #ifndef LETS_GET_SMALL
816 	return (state_func_t)runcom;
817 #else /* LETS_GET_SMALL */
818 	return (state_func_t)single_user;
819 #endif /* LETS_GET_SMALL */
820 }
821 
822 #ifndef LETS_GET_SMALL
823 
824 /* ARGSUSED */
825 state_func_t
826 runetcrc(int trychroot)
827 {
828 	pid_t pid, wpid;
829 	int status;
830 	const char *argv[4];
831 	struct sigaction sa;
832 
833 	switch ((pid = fork())) {
834 	case 0:
835 		(void)sigemptyset(&sa.sa_mask);
836 		sa.sa_flags = 0;
837 		sa.sa_handler = SIG_IGN;
838 		(void)sigaction(SIGTSTP, &sa, NULL);
839 		(void)sigaction(SIGHUP, &sa, NULL);
840 
841 		setctty(_PATH_CONSOLE);
842 
843 		argv[0] = "sh";
844 		argv[1] = _PATH_RUNCOM;
845 		argv[2] = (runcom_mode == AUTOBOOT ? "autoboot" : 0);
846 		argv[3] = 0;
847 
848 		(void)sigprocmask(SIG_SETMASK, &sa.sa_mask, NULL);
849 
850 #ifdef CHROOT
851 		if (trychroot)
852 			if (chroot(rootdir) != 0) {
853 				warning("failed to chroot to `%s': %m",
854 				    rootdir);
855 				_exit(4); 	/* force single user mode */
856 			}
857 #endif /* CHROOT */
858 
859 		(void)execv(INIT_BSHELL, __UNCONST(argv));
860 		stall("can't exec `%s' for `%s': %m", INIT_BSHELL, _PATH_RUNCOM);
861 		_exit(5);	/* force single user mode */
862 		/*NOTREACHED*/
863 	case -1:
864 		emergency("can't fork for `%s' on `%s': %m", INIT_BSHELL,
865 		    _PATH_RUNCOM);
866 		while (waitpid(-1, NULL, WNOHANG) > 0)
867 			continue;
868 		(void)sleep(STALL_TIMEOUT);
869 		return (state_func_t)single_user;
870 	default:
871 		break;
872 	}
873 
874 	/*
875 	 * Copied from single_user().  This is a bit paranoid.
876 	 */
877 	do {
878 		if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1)
879 			collect_child(wpid, status);
880 		if (wpid == -1) {
881 			if (errno == EINTR)
882 				continue;
883 			warning("wait for `%s' on `%s' failed: %m; going to "
884 			    "single user mode", INIT_BSHELL, _PATH_RUNCOM);
885 			return (state_func_t)single_user;
886 		}
887 		if (wpid == pid && WIFSTOPPED(status)) {
888 			warning("`%s' on `%s' stopped, restarting",
889 			    INIT_BSHELL, _PATH_RUNCOM);
890 			(void)kill(pid, SIGCONT);
891 			wpid = -1;
892 		}
893 	} while (wpid != pid);
894 
895 	if (WIFSIGNALED(status) && WTERMSIG(status) == SIGTERM &&
896 	    requested_transition == catatonia) {
897 		/* /etc/rc executed /sbin/reboot; wait for the end quietly */
898 		sigset_t s;
899 
900 		(void)sigfillset(&s);
901 		for (;;)
902 			(void)sigsuspend(&s);
903 	}
904 
905 	if (!WIFEXITED(status)) {
906 		warning("`%s' on `%s' terminated abnormally, going to "
907 		    "single user mode", INIT_BSHELL, _PATH_RUNCOM);
908 		return (state_func_t)single_user;
909 	}
910 
911 	if (WEXITSTATUS(status))
912 		return (state_func_t)single_user;
913 
914 	return (state_func_t)read_ttys;
915 }
916 
917 /*
918  * Run the system startup script.
919  */
920 state_func_t
921 runcom(void)
922 {
923 	state_func_t next_step;
924 
925 	/* Run /etc/rc and choose next state depending on the result. */
926 	next_step = runetcrc(0);
927 	if (next_step != (state_func_t)read_ttys)
928 		return (state_func_t)next_step;
929 
930 #ifdef CHROOT
931 	/*
932 	 * If init.root sysctl does not point to "/", we'll chroot and run
933 	 * The Real(tm) /etc/rc now.  Global variable rootdir will tell us
934 	 * where to go.
935 	 */
936 	if (shouldchroot()) {
937 		next_step = runetcrc(1);
938 		if (next_step != (state_func_t)read_ttys)
939 			return (state_func_t)next_step;
940 
941 		did_multiuser_chroot = 1;
942 	} else {
943 		did_multiuser_chroot = 0;
944 	}
945 #endif /* CHROOT */
946 
947 	/*
948 	 * Regardless of whether in chroot or not, we booted successfuly.
949 	 * It's time to spawn gettys (ie. next_step's value at this point).
950 	 */
951 	runcom_mode = AUTOBOOT;		/* the default */
952 	/* NB: should send a message to the session logger to avoid blocking. */
953 #ifdef SUPPORT_UTMPX
954 	logwtmpx("~", "reboot", "", 0, INIT_PROCESS);
955 #endif
956 #ifdef SUPPORT_UTMP
957 	logwtmp("~", "reboot", "");
958 #endif
959 	return (state_func_t)read_ttys;
960 }
961 
962 /*
963  * Open the session database.
964  *
965  * NB: We could pass in the size here; is it necessary?
966  */
967 int
968 start_session_db(void)
969 {
970 
971 	if (session_db && (*session_db->close)(session_db))
972 		emergency("session database close: %m");
973 	if ((session_db = dbopen(NULL, O_RDWR, 0, DB_HASH, NULL)) == 0) {
974 		emergency("session database open: %m");
975 		return 1;
976 	}
977 	return 0;
978 
979 }
980 
981 /*
982  * Add a new login session.
983  */
984 void
985 add_session(session_t *sp)
986 {
987 	DBT key;
988 	DBT data;
989 
990 	if (session_db == NULL)
991 		return;
992 
993 	key.data = &sp->se_process;
994 	key.size = sizeof sp->se_process;
995 	data.data = &sp;
996 	data.size = sizeof sp;
997 
998 	if ((*session_db->put)(session_db, &key, &data, 0))
999 		emergency("insert %d: %m", sp->se_process);
1000 #ifdef SUPPORT_UTMPX
1001 	session_utmpx(sp, 1);
1002 #endif
1003 }
1004 
1005 /*
1006  * Delete an old login session.
1007  */
1008 void
1009 del_session(session_t *sp)
1010 {
1011 	DBT key;
1012 
1013 	key.data = &sp->se_process;
1014 	key.size = sizeof sp->se_process;
1015 
1016 	if ((*session_db->del)(session_db, &key, 0))
1017 		emergency("delete %d: %m", sp->se_process);
1018 #ifdef SUPPORT_UTMPX
1019 	session_utmpx(sp, 0);
1020 #endif
1021 }
1022 
1023 /*
1024  * Look up a login session by pid.
1025  */
1026 session_t *
1027 find_session(pid_t pid)
1028 {
1029 	DBT key;
1030 	DBT data;
1031 	session_t *ret;
1032 
1033 	if (session_db == NULL)
1034 		return NULL;
1035 
1036 	key.data = &pid;
1037 	key.size = sizeof pid;
1038 	if ((*session_db->get)(session_db, &key, &data, 0) != 0)
1039 		return 0;
1040 	(void)memmove(&ret, data.data, sizeof(ret));
1041 	return ret;
1042 }
1043 
1044 /*
1045  * Construct an argument vector from a command line.
1046  */
1047 char **
1048 construct_argv(char *command)
1049 {
1050 	int argc = 0;
1051 	char **argv = malloc(((strlen(command) + 1) / 2 + 1) * sizeof (char *));
1052 	static const char separators[] = " \t";
1053 
1054 	if (argv == NULL)
1055 		return NULL;
1056 
1057 	if ((argv[argc++] = strtok(command, separators)) == 0) {
1058 		free(argv);
1059 		return NULL;
1060 	}
1061 	while ((argv[argc++] = strtok(NULL, separators)) != NULL)
1062 		continue;
1063 	return argv;
1064 }
1065 
1066 /*
1067  * Deallocate a session descriptor.
1068  */
1069 void
1070 free_session(session_t *sp)
1071 {
1072 
1073 	free(sp->se_device);
1074 	if (sp->se_getty) {
1075 		free(sp->se_getty);
1076 		free(sp->se_getty_argv);
1077 	}
1078 	if (sp->se_window) {
1079 		free(sp->se_window);
1080 		free(sp->se_window_argv);
1081 	}
1082 	free(sp);
1083 }
1084 
1085 /*
1086  * Allocate a new session descriptor.
1087  */
1088 session_t *
1089 new_session(session_t *sprev, int session_index, struct ttyent *typ)
1090 {
1091 	session_t *sp;
1092 
1093 	if ((typ->ty_status & TTY_ON) == 0 || typ->ty_name == NULL ||
1094 	    typ->ty_getty == NULL)
1095 		return NULL;
1096 
1097 	sp = malloc(sizeof (session_t));
1098 	if (sp == NULL)
1099 		return NULL;
1100 	(void)memset(sp, 0, sizeof *sp);
1101 
1102 	sp->se_flags = SE_PRESENT;
1103 	sp->se_index = session_index;
1104 
1105 	(void)asprintf(&sp->se_device, "%s%s", _PATH_DEV, typ->ty_name);
1106 	if (!sp->se_device)
1107 		return NULL;
1108 
1109 	if (setupargv(sp, typ) == 0) {
1110 		free_session(sp);
1111 		return NULL;
1112 	}
1113 
1114 	sp->se_next = NULL;
1115 	if (sprev == NULL) {
1116 		sessions = sp;
1117 		sp->se_prev = NULL;
1118 	} else {
1119 		sprev->se_next = sp;
1120 		sp->se_prev = sprev;
1121 	}
1122 
1123 	return sp;
1124 }
1125 
1126 /*
1127  * Calculate getty and if useful window argv vectors.
1128  */
1129 int
1130 setupargv(session_t *sp, struct ttyent *typ)
1131 {
1132 
1133 	if (sp->se_getty) {
1134 		free(sp->se_getty);
1135 		free(sp->se_getty_argv);
1136 	}
1137 	(void)asprintf(&sp->se_getty, "%s %s", typ->ty_getty, typ->ty_name);
1138 	if (!sp->se_getty)
1139 		return 0;
1140 	sp->se_getty_argv = construct_argv(sp->se_getty);
1141 	if (sp->se_getty_argv == NULL) {
1142 		warning("can't parse getty for port `%s'", sp->se_device);
1143 		free(sp->se_getty);
1144 		sp->se_getty = NULL;
1145 		return 0;
1146 	}
1147 	if (typ->ty_window) {
1148 		if (sp->se_window)
1149 			free(sp->se_window);
1150 		sp->se_window = strdup(typ->ty_window);
1151 		sp->se_window_argv = construct_argv(sp->se_window);
1152 		if (sp->se_window_argv == NULL) {
1153 			warning("can't parse window for port `%s'",
1154 			    sp->se_device);
1155 			free(sp->se_window);
1156 			sp->se_window = NULL;
1157 			return 0;
1158 		}
1159 	}
1160 	return 1;
1161 }
1162 
1163 /*
1164  * Walk the list of ttys and create sessions for each active line.
1165  */
1166 state_func_t
1167 read_ttys(void)
1168 {
1169 	int session_index = 0;
1170 	session_t *sp, *snext;
1171 	struct ttyent *typ;
1172 
1173 #ifdef SUPPORT_UTMPX
1174 	if (sessions == NULL) {
1175 		struct stat st;
1176 
1177 		make_utmpx("", BOOT_MSG, BOOT_TIME, 0, &boot_time, 0);
1178 
1179 		/*
1180 		 * If wtmpx is not empty, pick the down time from there
1181 		 */
1182 		if (stat(_PATH_WTMPX, &st) != -1 && st.st_size != 0) {
1183 			struct timeval down_time;
1184 
1185 			TIMESPEC_TO_TIMEVAL(&down_time,
1186 			    st.st_atime > st.st_mtime ?
1187 			    &st.st_atimespec : &st.st_mtimespec);
1188 			make_utmpx("", DOWN_MSG, DOWN_TIME, 0, &down_time, 0);
1189 		}
1190 	}
1191 #endif
1192 	/*
1193 	 * Destroy any previous session state.
1194 	 * There shouldn't be any, but just in case...
1195 	 */
1196 	for (sp = sessions; sp; sp = snext) {
1197 #ifndef LETS_GET_SMALL
1198 		if (sp->se_process)
1199 			clear_session_logs(sp, 0);
1200 #endif
1201 		snext = sp->se_next;
1202 		free_session(sp);
1203 	}
1204 	sessions = NULL;
1205 
1206 	if (start_session_db()) {
1207 		warning("start_session_db failed, death");
1208 #ifdef CHROOT
1209 		/* If /etc/rc ran in chroot, we want to kill any survivors. */
1210 		if (did_multiuser_chroot)
1211 			return (state_func_t)death;
1212 		else
1213 #endif /* CHROOT */
1214 			return (state_func_t)single_user;
1215 	}
1216 
1217 	(void)do_setttyent();
1218 
1219 	/*
1220 	 * Allocate a session entry for each active port.
1221 	 * Note that sp starts at 0.
1222 	 */
1223 	while ((typ = getttyent()) != NULL)
1224 		if ((snext = new_session(sp, ++session_index, typ)) != NULL)
1225 			sp = snext;
1226 	(void)endttyent();
1227 
1228 	return (state_func_t)multi_user;
1229 }
1230 
1231 /*
1232  * Start a window system running.
1233  */
1234 void
1235 start_window_system(session_t *sp)
1236 {
1237 	pid_t pid;
1238 	sigset_t mask;
1239 
1240 	if ((pid = fork()) == -1) {
1241 		emergency("can't fork for window system on port `%s': %m",
1242 		    sp->se_device);
1243 		/* hope that getty fails and we can try again */
1244 		return;
1245 	}
1246 
1247 	if (pid)
1248 		return;
1249 
1250 	(void)sigemptyset(&mask);
1251 	(void)sigprocmask(SIG_SETMASK, &mask, NULL);
1252 
1253 	if (setsid() < 0)
1254 		emergency("setsid failed (window): %m");
1255 
1256 	(void)execv(sp->se_window_argv[0], sp->se_window_argv);
1257 	stall("can't exec window system `%s' for port `%s': %m",
1258 	    sp->se_window_argv[0], sp->se_device);
1259 	_exit(6);
1260 }
1261 
1262 /*
1263  * Start a login session running.
1264  */
1265 pid_t
1266 start_getty(session_t *sp)
1267 {
1268 	pid_t pid;
1269 	sigset_t mask;
1270 	time_t current_time = time(NULL);
1271 
1272 	/*
1273 	 * fork(), not vfork() -- we can't afford to block.
1274 	 */
1275 	if ((pid = fork()) == -1) {
1276 		emergency("can't fork for getty on port `%s': %m",
1277 		    sp->se_device);
1278 		return -1;
1279 	}
1280 
1281 	if (pid)
1282 		return pid;
1283 
1284 #ifdef CHROOT
1285 	/* If /etc/rc did proceed inside chroot, we have to try as well. */
1286 	if (did_multiuser_chroot)
1287 		if (chroot(rootdir) != 0) {
1288 			stall("can't chroot getty `%s' inside `%s': %m",
1289 			    sp->se_getty_argv[0], rootdir);
1290 			_exit(7);
1291 		}
1292 #endif /* CHROOT */
1293 
1294 	if (current_time > sp->se_started.tv_sec &&
1295 	    current_time - sp->se_started.tv_sec < GETTY_SPACING) {
1296 		warning("getty repeating too quickly on port `%s', sleeping",
1297 		    sp->se_device);
1298 		(void)sleep(GETTY_SLEEP);
1299 	}
1300 
1301 	if (sp->se_window) {
1302 		start_window_system(sp);
1303 		(void)sleep(WINDOW_WAIT);
1304 	}
1305 
1306 	(void)sigemptyset(&mask);
1307 	(void)sigprocmask(SIG_SETMASK, &mask, (sigset_t *) 0);
1308 
1309 	(void)execv(sp->se_getty_argv[0], sp->se_getty_argv);
1310 	stall("can't exec getty `%s' for port `%s': %m",
1311 	    sp->se_getty_argv[0], sp->se_device);
1312 	_exit(8);
1313 	/*NOTREACHED*/
1314 }
1315 #ifdef SUPPORT_UTMPX
1316 static void
1317 session_utmpx(const session_t *sp, int add)
1318 {
1319 	const char *name = sp->se_getty ? sp->se_getty :
1320 	    (sp->se_window ? sp->se_window : "");
1321 	const char *line = sp->se_device + sizeof(_PATH_DEV) - 1;
1322 
1323 	make_utmpx(name, line, add ? LOGIN_PROCESS : DEAD_PROCESS,
1324 	    sp->se_process, &sp->se_started, sp->se_index);
1325 }
1326 
1327 static void
1328 make_utmpx(const char *name, const char *line, int type, pid_t pid,
1329     const struct timeval *tv, int session)
1330 {
1331 	struct utmpx ut;
1332 	const char *eline;
1333 
1334 	(void)memset(&ut, 0, sizeof(ut));
1335 	(void)strlcpy(ut.ut_name, name, sizeof(ut.ut_name));
1336 	ut.ut_type = type;
1337 	(void)strlcpy(ut.ut_line, line, sizeof(ut.ut_line));
1338 	ut.ut_pid = pid;
1339 	if (tv)
1340 		ut.ut_tv = *tv;
1341 	else
1342 		(void)gettimeofday(&ut.ut_tv, NULL);
1343 	ut.ut_session = session;
1344 
1345 	eline = line + strlen(line);
1346 	if ((size_t)(eline - line) >= sizeof(ut.ut_id))
1347 		line = eline - sizeof(ut.ut_id);
1348 	(void)strncpy(ut.ut_id, line, sizeof(ut.ut_id));
1349 
1350 	if (pututxline(&ut) == NULL)
1351 		warning("can't add utmpx record for `%s': %m", ut.ut_line);
1352 	endutxent();
1353 }
1354 
1355 static char
1356 get_runlevel(const state_t s)
1357 {
1358 	if (s == (state_t)single_user)
1359 		return SINGLE_USER;
1360 	if (s == (state_t)runcom)
1361 		return RUNCOM;
1362 	if (s == (state_t)read_ttys)
1363 		return READ_TTYS;
1364 	if (s == (state_t)multi_user)
1365 		return MULTI_USER;
1366 	if (s == (state_t)clean_ttys)
1367 		return CLEAN_TTYS;
1368 	if (s == (state_t)catatonia)
1369 		return CATATONIA;
1370 	return DEATH;
1371 }
1372 
1373 static void
1374 utmpx_set_runlevel(char old, char new)
1375 {
1376 	struct utmpx ut;
1377 
1378 	/*
1379 	 * Don't record any transitions until we did the first transition
1380 	 * to read ttys, which is when we are guaranteed to have a read-write
1381 	 * /var. Perhaps use a different variable for this?
1382 	 */
1383 	if (sessions == NULL)
1384 		return;
1385 
1386 	(void)memset(&ut, 0, sizeof(ut));
1387 	(void)snprintf(ut.ut_line, sizeof(ut.ut_line), RUNLVL_MSG, new);
1388 	ut.ut_type = RUN_LVL;
1389 	(void)gettimeofday(&ut.ut_tv, NULL);
1390 	ut.ut_exit.e_exit = old;
1391 	ut.ut_exit.e_termination = new;
1392 	if (pututxline(&ut) == NULL)
1393 		warning("can't add utmpx record for `runlevel': %m");
1394 	endutxent();
1395 }
1396 #endif /* SUPPORT_UTMPX */
1397 
1398 #endif /* LETS_GET_SMALL */
1399 
1400 /*
1401  * Collect exit status for a child.
1402  * If an exiting login, start a new login running.
1403  */
1404 void
1405 collect_child(pid_t pid, int status)
1406 {
1407 #ifndef LETS_GET_SMALL
1408 	session_t *sp, *sprev, *snext;
1409 
1410 	if (! sessions)
1411 		return;
1412 
1413 	if ((sp = find_session(pid)) == NULL)
1414 		return;
1415 
1416 	clear_session_logs(sp, status);
1417 	del_session(sp);
1418 	sp->se_process = 0;
1419 
1420 	if (sp->se_flags & SE_SHUTDOWN) {
1421 		if ((sprev = sp->se_prev) != NULL)
1422 			sprev->se_next = sp->se_next;
1423 		else
1424 			sessions = sp->se_next;
1425 		if ((snext = sp->se_next) != NULL)
1426 			snext->se_prev = sp->se_prev;
1427 		free_session(sp);
1428 		return;
1429 	}
1430 
1431 	if ((pid = start_getty(sp)) == -1) {
1432 		/* serious trouble */
1433 		requested_transition = clean_ttys;
1434 		return;
1435 	}
1436 
1437 	sp->se_process = pid;
1438 	(void)gettimeofday(&sp->se_started, NULL);
1439 	add_session(sp);
1440 #endif /* LETS_GET_SMALL */
1441 }
1442 
1443 /*
1444  * Catch a signal and request a state transition.
1445  */
1446 void
1447 transition_handler(int sig)
1448 {
1449 
1450 	switch (sig) {
1451 #ifndef LETS_GET_SMALL
1452 	case SIGHUP:
1453 		requested_transition = clean_ttys;
1454 		break;
1455 	case SIGTERM:
1456 		requested_transition = death;
1457 		break;
1458 	case SIGTSTP:
1459 		requested_transition = catatonia;
1460 		break;
1461 #endif /* LETS_GET_SMALL */
1462 	default:
1463 		requested_transition = 0;
1464 		break;
1465 	}
1466 }
1467 
1468 #ifndef LETS_GET_SMALL
1469 /*
1470  * Take the system multiuser.
1471  */
1472 state_func_t
1473 multi_user(void)
1474 {
1475 	pid_t pid;
1476 	int status;
1477 	session_t *sp;
1478 
1479 	requested_transition = 0;
1480 
1481 	/*
1482 	 * If the administrator has not set the security level to -1
1483 	 * to indicate that the kernel should not run multiuser in secure
1484 	 * mode, and the run script has not set a higher level of security
1485 	 * than level 1, then put the kernel into secure mode.
1486 	 */
1487 	if (getsecuritylevel() == 0)
1488 		setsecuritylevel(1);
1489 
1490 	for (sp = sessions; sp; sp = sp->se_next) {
1491 		if (sp->se_process)
1492 			continue;
1493 		if ((pid = start_getty(sp)) == -1) {
1494 			/* serious trouble */
1495 			requested_transition = clean_ttys;
1496 			break;
1497 		}
1498 		sp->se_process = pid;
1499 		(void)gettimeofday(&sp->se_started, NULL);
1500 		add_session(sp);
1501 	}
1502 
1503 	while (!requested_transition)
1504 		if ((pid = waitpid(-1, &status, 0)) != -1)
1505 			collect_child(pid, status);
1506 
1507 	return (state_func_t)requested_transition;
1508 }
1509 
1510 /*
1511  * This is an n-squared algorithm.  We hope it isn't run often...
1512  */
1513 state_func_t
1514 clean_ttys(void)
1515 {
1516 	session_t *sp, *sprev;
1517 	struct ttyent *typ;
1518 	int session_index = 0;
1519 	int devlen;
1520 
1521 	for (sp = sessions; sp; sp = sp->se_next)
1522 		sp->se_flags &= ~SE_PRESENT;
1523 
1524 	(void)do_setttyent();
1525 
1526 	devlen = sizeof(_PATH_DEV) - 1;
1527 	while ((typ = getttyent()) != NULL) {
1528 		++session_index;
1529 
1530 		for (sprev = 0, sp = sessions; sp; sprev = sp, sp = sp->se_next)
1531 			if (strcmp(typ->ty_name, sp->se_device + devlen) == 0)
1532 				break;
1533 
1534 		if (sp) {
1535 			sp->se_flags |= SE_PRESENT;
1536 			if (sp->se_index != session_index) {
1537 				warning("port `%s' changed utmp index from "
1538 				    "%d to %d", sp->se_device, sp->se_index,
1539 				    session_index);
1540 				sp->se_index = session_index;
1541 			}
1542 			if ((typ->ty_status & TTY_ON) == 0 ||
1543 			    typ->ty_getty == 0) {
1544 				sp->se_flags |= SE_SHUTDOWN;
1545 				if (sp->se_process != 0)
1546 					(void)kill(sp->se_process, SIGHUP);
1547 				continue;
1548 			}
1549 			sp->se_flags &= ~SE_SHUTDOWN;
1550 			if (setupargv(sp, typ) == 0) {
1551 				warning("can't parse getty for port `%s'",
1552 				    sp->se_device);
1553 				sp->se_flags |= SE_SHUTDOWN;
1554 				if (sp->se_process != 0)
1555 					(void)kill(sp->se_process, SIGHUP);
1556 			}
1557 			continue;
1558 		}
1559 
1560 		(void)new_session(sprev, session_index, typ);
1561 	}
1562 
1563 	(void)endttyent();
1564 
1565 	for (sp = sessions; sp; sp = sp->se_next)
1566 		if ((sp->se_flags & SE_PRESENT) == 0) {
1567 			sp->se_flags |= SE_SHUTDOWN;
1568 			if (sp->se_process != 0)
1569 				(void)kill(sp->se_process, SIGHUP);
1570 		}
1571 
1572 	return (state_func_t)multi_user;
1573 }
1574 
1575 /*
1576  * Block further logins.
1577  */
1578 state_func_t
1579 catatonia(void)
1580 {
1581 	session_t *sp;
1582 
1583 	for (sp = sessions; sp; sp = sp->se_next)
1584 		sp->se_flags |= SE_SHUTDOWN;
1585 
1586 	return (state_func_t)multi_user;
1587 }
1588 #endif /* LETS_GET_SMALL */
1589 
1590 /*
1591  * Note SIGALRM.
1592  */
1593 void
1594 /*ARGSUSED*/
1595 alrm_handler(int sig)
1596 {
1597 
1598 	clang = 1;
1599 }
1600 
1601 #ifndef LETS_GET_SMALL
1602 /*
1603  * Bring the system down to single user.
1604  */
1605 state_func_t
1606 death(void)
1607 {
1608 	session_t *sp;
1609 	int i, status;
1610 	pid_t pid;
1611 	static const int death_sigs[3] = { SIGHUP, SIGTERM, SIGKILL };
1612 
1613 	for (sp = sessions; sp; sp = sp->se_next)
1614 		sp->se_flags |= SE_SHUTDOWN;
1615 
1616 	/* NB: should send a message to the session logger to avoid blocking. */
1617 #ifdef SUPPORT_UTMPX
1618 	logwtmpx("~", "shutdown", "", 0, INIT_PROCESS);
1619 #endif
1620 #ifdef SUPPORT_UTMP
1621 	logwtmp("~", "shutdown", "");
1622 #endif
1623 
1624 	for (i = 0; i < 3; ++i) {
1625 		if (kill(-1, death_sigs[i]) == -1 && errno == ESRCH)
1626 			return (state_func_t)single_user;
1627 
1628 		clang = 0;
1629 		(void)alarm(DEATH_WATCH);
1630 		do
1631 			if ((pid = waitpid(-1, &status, 0)) != -1)
1632 				collect_child(pid, status);
1633 		while (clang == 0 && errno != ECHILD);
1634 
1635 		if (errno == ECHILD)
1636 			return (state_func_t)single_user;
1637 	}
1638 
1639 	warning("some processes would not die; ps axl advised");
1640 
1641 	return (state_func_t)single_user;
1642 }
1643 #endif /* LETS_GET_SMALL */
1644 
1645 #ifdef MFS_DEV_IF_NO_CONSOLE
1646 
1647 static int
1648 mfs_dev(void)
1649 {
1650 	/*
1651 	 * We cannot print errors so we bail out silently...
1652 	 */
1653 	pid_t pid;
1654 	int status;
1655 
1656 	/* If we have /dev/console, assume all is OK  */
1657 	if (access(_PATH_CONSOLE, F_OK) == 0)
1658 		return 0;
1659 
1660 #if 0	/* Useful for testing MAKEDEV */
1661 	/* Mount an mfs over /mnt so we can create a console entry */
1662 	switch ((pid = fork())) {
1663 	case 0:
1664 		(void)execl(INIT_MOUNT_MFS, "mount_mfs",
1665 		    "-b", "4096", "-f", "512",
1666 		    "-s", 64, "-n", 10,
1667 		    "-p", "0755",
1668 		    "swap", "/mnt", NULL);
1669 		_exit(9);
1670 		/*NOTREACHED*/
1671 
1672 	case -1:
1673 		return(-1);
1674 
1675 	default:
1676 		if (waitpid(pid, &status, 0) == -1)
1677 			return(-1);
1678 		if (status != 0)
1679 			return(-1);
1680 		break;
1681 	}
1682 
1683 	{
1684 		dev_t dev;
1685 #ifdef CPU_CONSDEV
1686 		static int name[2] = { CTL_MACHDEP, CPU_CONSDEV };
1687 		size_t olen;
1688 		olen = sizeof(dev);
1689 		if (sysctl(name, sizeof(name) / sizeof(name[0]), &dev, &olen,
1690 		    NULL, 0) == -1)
1691 #endif
1692 			dev = makedev(0, 0);
1693 
1694 		/* Make a console for us, so we can see things happening */
1695 		if (mknod("/mnt/console", 0666 | S_IFCHR, dev) == -1)
1696 			return(-1);
1697 		(void)freopen("/mnt/console", "a", stderr);
1698 	}
1699 
1700 #endif
1701 
1702 	/* Run the makedev script to create devices */
1703 	switch ((pid = fork())) {
1704 	case 0:
1705 		(void)dup2(2, 1);	/* Give the script stdout */
1706 		if (chdir("/dev") == 0)
1707 			(void)execl(INIT_BSHELL, "sh",
1708 			    access("./MAKEDEV", X_OK) == 0
1709 				? "./MAKEDEV" : "/etc/MAKEDEV",
1710 			    "-MM", "init", NULL);
1711 		_exit(10);
1712 		/* NOTREACHED */
1713 
1714 	case -1:
1715 		break;
1716 
1717 	default:
1718 		if (waitpid(pid, &status, 0) == -1)
1719 			break;
1720 		if (status != 0)
1721 			warn("MAKEDEV exit status %d\n", status);
1722 		/*
1723 		 * If /dev/console got created, then return 0
1724 		 * regardless of MAKEDEV exit status.
1725 		 */
1726 		if (access(_PATH_CONSOLE, F_OK) == 0)
1727 			return 0;
1728 		_exit(11);
1729 	}
1730 	warn("Unable to run MAKEDEV");
1731 	_exit(12);
1732 }
1733 #endif
1734 
1735 int
1736 do_setttyent(void)
1737 {
1738 	(void)endttyent();
1739 #ifdef CHROOT
1740 	if (did_multiuser_chroot) {
1741 		char path[PATH_MAX];
1742 
1743 		(void)snprintf(path, sizeof(path), "%s/%s", rootdir, _PATH_TTYS);
1744 
1745 		return setttyentpath(path);
1746 	} else
1747 #endif /* CHROOT */
1748 		return setttyent();
1749 }
1750 
1751 #if !defined(LETS_GET_SMALL) && defined(CHROOT)
1752 
1753 int
1754 createsysctlnode()
1755 {
1756 	struct sysctlnode node;
1757 	int mib[2];
1758 	size_t len;
1759 
1760 	/*
1761 	 * Create top-level dynamic sysctl node.  Its child nodes will only
1762 	 * be readable by the superuser, since regular mortals should not
1763 	 * care ("Sssh, it's a secret!").
1764 	 */
1765 	len = sizeof(struct sysctlnode);
1766 	mib[0] = CTL_CREATE;
1767 
1768 	(void)memset(&node, 0, len);
1769 	node.sysctl_flags = SYSCTL_VERSION | CTLFLAG_READWRITE |
1770 	    CTLFLAG_PRIVATE | CTLTYPE_NODE;
1771 	node.sysctl_num = CTL_CREATE;
1772 	(void)snprintf(node.sysctl_name, SYSCTL_NAMELEN, "init");
1773 	if (sysctl(&mib[0], 1, &node, &len, &node, len) == -1) {
1774 		warning("could not create init node: %m");
1775 		return -1;
1776 	}
1777 
1778 	/*
1779 	 * Create second level dynamic node capable of holding pathname.
1780 	 * Provide "/" as the default value.
1781 	 */
1782 	len = sizeof(struct sysctlnode);
1783 	mib[0] = node.sysctl_num;
1784 	mib[1] = CTL_CREATE;
1785 
1786 	(void)memset(&node, 0, len);
1787 	node.sysctl_flags = SYSCTL_VERSION | CTLFLAG_READWRITE |
1788 	    CTLTYPE_STRING | CTLFLAG_OWNDATA;
1789 	node.sysctl_size = _POSIX_PATH_MAX;
1790 	node.sysctl_data = __UNCONST("/");
1791 	node.sysctl_num = CTL_CREATE;
1792 	(void)snprintf(node.sysctl_name, SYSCTL_NAMELEN, "root");
1793 	if (sysctl(&mib[0], 2, NULL, NULL, &node, len) == -1) {
1794 		warning("could not create init.root node: %m");
1795 		return -1;
1796 	}
1797 
1798 	return 0;
1799 }
1800 
1801 int
1802 shouldchroot()
1803 {
1804 	struct sysctlnode node;
1805 	size_t len, cnt;
1806 	int mib;
1807 
1808 	len = sizeof(struct sysctlnode);
1809 
1810 	if (sysctlbyname("init.root", rootdir, &len, NULL, 0) == -1) {
1811 		warning("could not read init.root: %m");
1812 
1813 		/* Child killed our node. Recreate it. */
1814 		if (errno == ENOENT) {
1815 			/* Destroy whatever is left, recreate from scratch. */
1816 			if (sysctlnametomib("init", &mib, &cnt) != -1) {
1817 				(void)memset(&node, 0, sizeof(node));
1818 				node.sysctl_flags = SYSCTL_VERSION;
1819 				node.sysctl_num = mib;
1820 				mib = CTL_DESTROY;
1821 
1822 				(void)sysctl(&mib, 1, NULL, NULL, &node,
1823 				    sizeof(node));
1824 			}
1825 
1826 			(void)createsysctlnode();
1827 		}
1828 
1829 		/* We certainly won't chroot. */
1830 		return 0;
1831 	}
1832 
1833 	if (rootdir[len] != '\0' || strlen(rootdir) != len - 1) {
1834 		warning("init.root is not a string");
1835 		return 0;
1836 	}
1837 
1838 	if (strcmp(rootdir, "/") == 0)
1839 		return 0;
1840 
1841 	return 1;
1842 }
1843 
1844 #endif /* !LETS_GET_SMALL && CHROOT */
1845