xref: /minix/sbin/init/init.c (revision 84d9c625)
1 /*	$NetBSD: init.c,v 1.105 2012/11/09 06:27:17 msaitoh 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 1.105 2012/11/09 06:27:17 msaitoh 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 #ifdef SUPPORT_UTMP
72 #include <utmp.h>
73 #endif
74 #ifdef SUPPORT_UTMPX
75 #include <utmpx.h>
76 #endif
77 
78 #include <stdarg.h>
79 
80 #ifdef SECURE
81 #include <pwd.h>
82 #endif
83 
84 #include "pathnames.h"
85 
86 #define XSTR(x) #x
87 #define STR(x) XSTR(x)
88 
89 /*
90  * Sleep times; used to prevent thrashing.
91  */
92 #define	GETTY_SPACING		 5	/* N secs minimum getty spacing */
93 #define	GETTY_SLEEP		30	/* sleep N secs after spacing problem */
94 #define	WINDOW_WAIT		 3	/* wait N secs after starting window */
95 #define	STALL_TIMEOUT		30	/* wait N secs after warning */
96 #define	DEATH_WATCH		10	/* wait N secs for procs to die */
97 
98 static const struct timespec dtrtime = {.tv_sec = 0, .tv_nsec = 250000};
99 
100 #if defined(RESCUEDIR)
101 #define	INIT_BSHELL	RESCUEDIR "/sh"
102 #define	INIT_MOUNT_MFS	RESCUEDIR "/mount_mfs"
103 #define	INIT_PATH	RESCUEDIR ":" _PATH_STDPATH
104 #else
105 #define	INIT_BSHELL	_PATH_BSHELL
106 #define	INIT_MOUNT_MFS	"/sbin/mount_mfs"
107 #define	INIT_PATH	_PATH_STDPATH
108 #endif
109 
110 static void handle(sig_t, ...);
111 static void delset(sigset_t *, ...);
112 
113 static void stall(const char *, ...) __printflike(1, 2);
114 static void warning(const char *, ...) __printflike(1, 2);
115 static void emergency(const char *, ...) __printflike(1, 2);
116 __dead static void disaster(int);
117 
118 #if defined(__minix)
119 static void minixreboot(int);
120 static void minixpowerdown(int);
121 #else
122 static void badsys(int);
123 #endif /* defined(__minix) */
124 
125 /*
126  * We really need a recursive typedef...
127  * The following at least guarantees that the return type of (*state_t)()
128  * is sufficiently wide to hold a function pointer.
129  */
130 typedef long (*state_func_t)(void);
131 typedef state_func_t (*state_t)(void);
132 
133 #define	DEATH		'd'
134 #define	SINGLE_USER	's'
135 #define	RUNCOM		'r'
136 #define	READ_TTYS	't'
137 #define	MULTI_USER	'm'
138 #define	CLEAN_TTYS	'T'
139 #define	CATATONIA	'c'
140 
141 static state_func_t single_user(void);
142 #ifndef LETS_GET_SMALL
143 static state_func_t runcom(void);
144 static state_func_t read_ttys(void);
145 static state_func_t multi_user(void);
146 static state_func_t clean_ttys(void);
147 static state_func_t catatonia(void);
148 static state_func_t death(void);
149 #endif
150 
151 static enum { AUTOBOOT, FASTBOOT } runcom_mode = AUTOBOOT;
152 
153 static void transition(state_t);
154 static void setctty(const char *);
155 
156 typedef struct init_session {
157 	int	se_index;		/* index of entry in ttys file */
158 	pid_t	se_process;		/* controlling process */
159 	struct timeval	se_started;	/* used to avoid thrashing */
160 	int	se_flags;		/* status of session */
161 #define	SE_SHUTDOWN	0x1		/* session won't be restarted */
162 #define	SE_PRESENT	0x2		/* session is in /etc/ttys */
163 	char	*se_device;		/* filename of port */
164 	char	*se_getty;		/* what to run on that port */
165 	char	**se_getty_argv;	/* pre-parsed argument array */
166 	char	*se_window;		/* window system (started only once) */
167 	char	**se_window_argv;	/* pre-parsed argument array */
168 	struct	init_session *se_prev;
169 	struct	init_session *se_next;
170 } session_t;
171 
172 static void collect_child(pid_t, int);
173 static int clang;
174 static void transition_handler(int);
175 static void alrm_handler(int);
176 static int has_securelevel(void);
177 static int securelevel_present;
178 
179 #ifndef LETS_GET_SMALL
180 static int do_setttyent(void);
181 static void start_window_system(session_t *);
182 static char **construct_argv(char *);
183 static int setupargv(session_t *, struct ttyent *);
184 static pid_t start_getty(session_t *);
185 static void free_session(session_t *);
186 static session_t *new_session(session_t *, int, struct ttyent *);
187 static session_t *sessions;
188 static void setsecuritylevel(int);
189 static int getsecuritylevel(void);
190 static int start_session_db(void);
191 static void add_session(session_t *);
192 static void del_session(session_t *);
193 static session_t *find_session(pid_t);
194 static DB *session_db;
195 static state_t requested_transition = runcom;
196 
197 static void clear_session_logs(session_t *, int);
198 static state_func_t runetcrc(int);
199 #ifdef SUPPORT_UTMPX
200 static struct timeval boot_time;
201 static state_t current_state = death;
202 static void session_utmpx(const session_t *, int);
203 static void make_utmpx(const char *, const char *, int, pid_t,
204     const struct timeval *, int);
205 static char get_runlevel(const state_t);
206 static void utmpx_set_runlevel(char, char);
207 #endif
208 
209 #ifdef CHROOT
210 static int did_multiuser_chroot = 0;
211 static char rootdir[PATH_MAX];
212 static int shouldchroot(void);
213 static int createsysctlnode(void);
214 #endif /* CHROOT */
215 
216 #else /* LETS_GET_SMALL */
217 static state_t requested_transition = single_user;
218 #endif /* !LETS_GET_SMALL */
219 
220 #ifdef MFS_DEV_IF_NO_CONSOLE
221 
222 static int mfs_dev(void);
223 
224 #endif
225 
226 /*
227  * The mother of all processes.
228  */
229 int
230 main(int argc, char **argv)
231 {
232 	struct sigaction sa;
233 	sigset_t mask;
234 #ifndef LETS_GET_SMALL
235 	int c;
236 
237 #ifdef SUPPORT_UTMPX
238 	(void)gettimeofday(&boot_time, NULL);
239 #endif /* SUPPORT_UTMPX */
240 
241 	/* Dispose of random users. */
242 	if (getuid() != 0) {
243 		errno = EPERM;
244 		err(1, NULL);
245 	}
246 
247 	/* System V users like to reexec init. */
248 	if (getpid() != 1)
249 		errx(1, "already running");
250 #endif
251 
252 	/*
253 	 * Create an initial session.
254 	 */
255 	if (setsid() < 0)
256 		warn("initial setsid() failed");
257 
258 	/*
259 	 * Establish an initial user so that programs running
260 	 * single user do not freak out and die (like passwd).
261 	 */
262 #if !defined(__minix)
263 	if (setlogin("root") < 0)
264 		warn("setlogin() failed");
265 #endif /* !defined(__minix) */
266 
267 
268 #ifdef MFS_DEV_IF_NO_CONSOLE
269 	if (mfs_dev() == -1)
270 		requested_transition = single_user;
271 #endif
272 
273 #ifndef LETS_GET_SMALL
274 	/*
275 	 * Note that this does NOT open a file...
276 	 * Does 'init' deserve its own facility number?
277 	 */
278 	openlog("init", LOG_CONS, LOG_AUTH);
279 #endif /* LETS_GET_SMALL */
280 
281 
282 #ifndef LETS_GET_SMALL
283 	/*
284 	 * This code assumes that we always get arguments through flags,
285 	 * never through bits set in some random machine register.
286 	 */
287 	while ((c = getopt(argc, argv, "sf")) != -1)
288 		switch (c) {
289 		case 's':
290 			requested_transition = single_user;
291 			break;
292 		case 'f':
293 			runcom_mode = FASTBOOT;
294 			break;
295 		default:
296 			warning("unrecognized flag `%c'", c);
297 			break;
298 		}
299 
300 	if (optind != argc)
301 		warning("ignoring excess arguments");
302 #else /* LETS_GET_SMALL */
303 	requested_transition = single_user;
304 #endif /* LETS_GET_SMALL */
305 
306 	/*
307 	 * We catch or block signals rather than ignore them,
308 	 * so that they get reset on exec.
309 	 */
310 #if !defined(__minix)
311 	handle(badsys, SIGSYS, 0);
312 	handle(disaster, SIGABRT, SIGFPE, SIGILL, SIGSEGV,
313 	       SIGBUS, SIGXCPU, SIGXFSZ, 0);
314 #else
315 	handle(minixreboot, SIGABRT, 0);
316 	handle(minixpowerdown, SIGUSR1, 0);
317 	handle(disaster, SIGFPE, SIGILL, SIGSEGV, SIGBUS, 0);
318 #endif /* !defined(__minix) */
319 	handle(transition_handler, SIGHUP, SIGTERM, SIGTSTP, 0);
320 	handle(alrm_handler, SIGALRM, 0);
321 	(void)sigfillset(&mask);
322 #if !defined(__minix)
323 	delset(&mask, SIGABRT, SIGFPE, SIGILL, SIGSEGV, SIGBUS, SIGSYS,
324 	    SIGXCPU, SIGXFSZ, SIGHUP, SIGTERM, SIGTSTP, SIGALRM, 0);
325 #else
326 	delset(&mask, SIGABRT, SIGFPE, SIGILL, SIGSEGV, SIGBUS,
327 	    SIGHUP, SIGTERM, SIGTSTP, SIGALRM, 0);
328 #endif /* !defined(__minix) */
329 	(void)sigprocmask(SIG_SETMASK, &mask, NULL);
330 	(void)sigemptyset(&sa.sa_mask);
331 	sa.sa_flags = 0;
332 	sa.sa_handler = SIG_IGN;
333 	(void)sigaction(SIGTTIN, &sa, NULL);
334 	(void)sigaction(SIGTTOU, &sa, NULL);
335 
336 	/*
337 	 * Paranoia.
338 	 */
339 	(void)close(0);
340 	(void)close(1);
341 	(void)close(2);
342 
343 #if !defined(LETS_GET_SMALL) && defined(CHROOT)
344 	/* Create "init.root" sysctl node. */
345 	(void)createsysctlnode();
346 #endif /* !LETS_GET_SMALL && CHROOT*/
347 
348 	/*
349 	 * Securelevel might not be supported by the kernel. Query for it, and
350 	 * set a variable indicating whether we should attempt anything with it
351 	 * or not.
352 	 */
353 	securelevel_present = has_securelevel();
354 
355 	/*
356 	 * Start the state machine.
357 	 */
358 	transition(requested_transition);
359 
360 	/*
361 	 * Should never reach here.
362 	 */
363 	return 1;
364 }
365 
366 /*
367  * Associate a function with a signal handler.
368  */
369 static void
370 handle(sig_t handler, ...)
371 {
372 	int sig;
373 	struct sigaction sa;
374 	sigset_t mask_everything;
375 	va_list ap;
376 
377 	va_start(ap, handler);
378 
379 	sa.sa_handler = handler;
380 	(void)sigfillset(&mask_everything);
381 
382 	while ((sig = va_arg(ap, int)) != 0) {
383 		sa.sa_mask = mask_everything;
384 		/* XXX SA_RESTART? */
385 		sa.sa_flags = sig == SIGCHLD ? SA_NOCLDSTOP : 0;
386 		(void)sigaction(sig, &sa, NULL);
387 	}
388 	va_end(ap);
389 }
390 
391 /*
392  * Delete a set of signals from a mask.
393  */
394 static void
395 delset(sigset_t *maskp, ...)
396 {
397 	int sig;
398 	va_list ap;
399 
400 	va_start(ap, maskp);
401 
402 	while ((sig = va_arg(ap, int)) != 0)
403 		(void)sigdelset(maskp, sig);
404 	va_end(ap);
405 }
406 
407 #if 0	/* Enable to get error messages from init ! */
408 #define vsyslog(level, fmt, ap) print_console(level, fmt, ap)
409 #define closelog()
410 
411 static void
412 print_console(int level, const char *message, va_list ap)
413 {
414 	/*
415 	 * XXX: syslog seems to just plain not work in console-only
416 	 * XXX: situation... that should be fixed.  Let's leave this
417 	 * XXX: note + code here in case someone gets in trouble and
418 	 * XXX: wants to debug. -- Jachym Holecek <freza@liberouter.org>
419 	 */
420 	char errbuf[1024];
421 	int fd, len;
422 
423 	/* We can't do anything on errors, anyway... */
424 	fd = open(_PATH_CONSOLE, O_WRONLY);
425 	if (fd == -1)
426 		return ;
427 
428 	/* %m will get lost... */
429 	len = vsnprintf(errbuf, sizeof(errbuf), message, ap);
430 	(void)write(fd, (void *)errbuf, len);
431 	(void)close(fd);
432 }
433 #endif
434 
435 /*
436  * Log a message and sleep for a while (to give someone an opportunity
437  * to read it and to save log or hardcopy output if the problem is chronic).
438  * NB: should send a message to the session logger to avoid blocking.
439  */
440 static void
441 stall(const char *message, ...)
442 {
443 	va_list ap;
444 
445 	va_start(ap, message);
446 	vsyslog(LOG_ALERT, message, ap);
447 	va_end(ap);
448 	closelog();
449 	(void)sleep(STALL_TIMEOUT);
450 }
451 
452 /*
453  * Like stall(), but doesn't sleep.
454  * If cpp had variadic macros, the two functions could be #defines for another.
455  * NB: should send a message to the session logger to avoid blocking.
456  */
457 static void
458 warning(const char *message, ...)
459 {
460 	va_list ap;
461 
462 	va_start(ap, message);
463 	vsyslog(LOG_ALERT, message, ap);
464 	va_end(ap);
465 	closelog();
466 }
467 
468 /*
469  * Log an emergency message.
470  * NB: should send a message to the session logger to avoid blocking.
471  */
472 static void
473 emergency(const char *message, ...)
474 {
475 	va_list ap;
476 
477 	va_start(ap, message);
478 	vsyslog(LOG_EMERG, message, ap);
479 	va_end(ap);
480 	closelog();
481 }
482 
483 #if !defined(__minix)
484 /*
485  * Catch a SIGSYS signal.
486  *
487  * These may arise if a system does not support sysctl.
488  * We tolerate up to 25 of these, then throw in the towel.
489  */
490 static void
491 badsys(int sig)
492 {
493 	static int badcount = 0;
494 
495 	if (badcount++ < 25)
496 		return;
497 	disaster(sig);
498 }
499 #endif /* !defined(__minix) */
500 
501 /*
502  * Catch an unexpected signal.
503  */
504 static void
505 disaster(int sig)
506 {
507 
508 	emergency("fatal signal: %s", strsignal(sig));
509 	(void)sleep(STALL_TIMEOUT);
510 	_exit(sig);		/* reboot */
511 }
512 
513 #if defined(__minix)
514 /*
515  * controlled reboot - minix tradition, SIGABRT by tty
516  */
517 static void
518 minixreboot(int sig)
519 {
520 	if(fork() == 0) {
521 		(void)execl("/sbin/shutdown",
522 			"shutdown", "-r", "now", "CTRL-ALT_DEL", NULL);
523 		_exit(1);
524 	}
525 }
526 
527 /*
528  * controlled powerdown
529  */
530 static void
531 minixpowerdown(int sig)
532 {
533 	if(fork() == 0) {
534 		(void)execl("/sbin/shutdown",
535 			"shutdown", "-p", "now", "CTRL-ALT_DEL", NULL);
536 		_exit(1);
537 	}
538 }
539 #endif /* defined(__minix) */
540 
541 /*
542  * Check if securelevel is present.
543  */
544 static int
545 has_securelevel(void)
546 {
547 #if defined(__minix)
548 	return 0;
549 #else
550 #ifdef KERN_SECURELVL
551 	int name[2], curlevel;
552 	size_t len;
553 
554 	name[0] = CTL_KERN;
555 	name[1] = KERN_SECURELVL;
556 	len = sizeof curlevel;
557 	if (sysctl(name, 2, &curlevel, &len, NULL, 0) == -1) {
558 		/* If it doesn't exist, it's okay. */
559 		if (errno == ENOENT)
560 			return 0;
561 	}
562 	return 1;
563 #else
564 	return 0;
565 #endif
566 #endif /* defined(__minix) */
567 }
568 
569 /*
570  * Get the security level of the kernel.
571  */
572 static int
573 getsecuritylevel(void)
574 {
575 #ifdef KERN_SECURELVL
576 	int name[2], curlevel;
577 	size_t len;
578 
579 	if (!securelevel_present)
580 		return -1;
581 
582 	name[0] = CTL_KERN;
583 	name[1] = KERN_SECURELVL;
584 	len = sizeof curlevel;
585 	if (sysctl(name, 2, &curlevel, &len, NULL, 0) == -1) {
586 		emergency("cannot get kernel security level: %m");
587 		return -1;
588 	}
589 	return curlevel;
590 #else
591 	return -1;
592 #endif
593 }
594 
595 /*
596  * Set the security level of the kernel.
597  */
598 static void
599 setsecuritylevel(int newlevel)
600 {
601 #ifdef KERN_SECURELVL
602 	int name[2], curlevel;
603 
604 	if (!securelevel_present)
605 		return;
606 
607 	curlevel = getsecuritylevel();
608 	if (newlevel == curlevel)
609 		return;
610 	name[0] = CTL_KERN;
611 	name[1] = KERN_SECURELVL;
612 	if (sysctl(name, 2, NULL, NULL, &newlevel, sizeof newlevel) == -1) {
613 		emergency("cannot change kernel security level from"
614 		    " %d to %d: %m", curlevel, newlevel);
615 		return;
616 	}
617 #ifdef SECURE
618 	warning("kernel security level changed from %d to %d",
619 	    curlevel, newlevel);
620 #endif
621 #endif
622 }
623 
624 /*
625  * Change states in the finite state machine.
626  * The initial state is passed as an argument.
627  */
628 static void
629 transition(state_t s)
630 {
631 
632 	if (s == NULL)
633 		return;
634 	for (;;) {
635 #ifdef SUPPORT_UTMPX
636 #ifndef LETS_GET_SMALL
637 		utmpx_set_runlevel(get_runlevel(current_state),
638 		    get_runlevel(s));
639 		current_state = s;
640 #endif
641 #endif
642 		s = (state_t)(*s)();
643 	}
644 }
645 
646 #ifndef LETS_GET_SMALL
647 /*
648  * Close out the accounting files for a login session.
649  * NB: should send a message to the session logger to avoid blocking.
650  */
651 static void
652 clear_session_logs(session_t *sp, int status)
653 {
654 #if defined(SUPPORT_UTMP) || defined(SUPPORT_UTMPX)
655 	char *line = sp->se_device + sizeof(_PATH_DEV) - 1;
656 #endif
657 
658 #ifdef SUPPORT_UTMPX
659 	if (logoutx(line, status, DEAD_PROCESS))
660 		logwtmpx(line, "", "", status, DEAD_PROCESS);
661 #endif
662 #ifdef SUPPORT_UTMP
663 	if (logout(line))
664 		logwtmp(line, "", "");
665 #endif
666 }
667 #endif
668 
669 /*
670  * Start a session and allocate a controlling terminal.
671  * Only called by children of init after forking.
672  */
673 static void
674 setctty(const char *name)
675 {
676 	int fd;
677 
678 #if !defined(__minix)
679 	(void)revoke(name);
680 #else
681 	if (setsid() < 0)
682 		warn("child setsid() failed");
683 #endif /* !defined(__minix) */
684 	(void)nanosleep(&dtrtime, NULL);	/* leave DTR low for a bit */
685 	if ((fd = open(name, O_RDWR)) == -1) {
686 		stall("can't open %s: %m", name);
687 		_exit(1);
688 	}
689 	if (login_tty(fd) == -1) {
690 		stall("can't get %s for controlling terminal: %m", name);
691 		_exit(2);
692 	}
693 }
694 
695 /*
696  * Bring the system up single user.
697  */
698 static state_func_t
699 single_user(void)
700 {
701 	pid_t pid, wpid;
702 	int status;
703 	int from_securitylevel;
704 	sigset_t mask;
705 	struct sigaction sa, satstp, sahup;
706 #ifdef ALTSHELL
707 	const char *shell = INIT_BSHELL;
708 #endif
709 	const char *argv[2];
710 #ifdef SECURE
711 	struct ttyent *typ;
712 	struct passwd *pp;
713 	char *clear, *password;
714 #endif
715 #ifdef ALTSHELL
716 	char altshell[128];
717 #endif /* ALTSHELL */
718 
719 #if !defined(LETS_GET_SMALL) && defined(CHROOT)
720 	/* Clear previous idea, just in case. */
721 	did_multiuser_chroot = 0;
722 #endif /* !LETS_GET_SMALL && CHROOT */
723 
724 	/*
725 	 * If the kernel is in secure mode, downgrade it to insecure mode.
726 	 */
727 	from_securitylevel = getsecuritylevel();
728 	if (from_securitylevel > 0)
729 		setsecuritylevel(0);
730 
731 	(void)sigemptyset(&sa.sa_mask);
732 	sa.sa_flags = 0;
733 	sa.sa_handler = SIG_IGN;
734 	(void)sigaction(SIGTSTP, &sa, &satstp);
735 	(void)sigaction(SIGHUP, &sa, &sahup);
736 	if ((pid = fork()) == 0) {
737 		/*
738 		 * Start the single user session.
739 		 */
740 		if (access(_PATH_CONSTTY, F_OK) == 0)
741 			setctty(_PATH_CONSTTY);
742 		else
743 			setctty(_PATH_CONSOLE);
744 
745 #ifdef SECURE
746 		/*
747 		 * Check the root password.
748 		 * We don't care if the console is 'on' by default;
749 		 * it's the only tty that can be 'off' and 'secure'.
750 		 */
751 		typ = getttynam("console");
752 		pp = getpwnam("root");
753 		if (typ && (from_securitylevel >=2 || (typ->ty_status
754 		    & TTY_SECURE) == 0) && pp && *pp->pw_passwd != '\0') {
755 			(void)fprintf(stderr,
756 			    "Enter root password, or ^D to go multi-user\n");
757 			for (;;) {
758 				clear = getpass("Password:");
759 				if (clear == 0 || *clear == '\0')
760 					_exit(0);
761 				password = crypt(clear, pp->pw_passwd);
762 				(void)memset(clear, 0, _PASSWORD_LEN);
763 				if (strcmp(password, pp->pw_passwd) == 0)
764 					break;
765 				warning("single-user login failed");
766 			}
767 		}
768 		(void)endttyent();
769 		endpwent();
770 #endif /* SECURE */
771 
772 #ifdef ALTSHELL
773 		(void)fprintf(stderr,
774 		    "Enter pathname of shell or RETURN for %s: ", shell);
775 		if (fgets(altshell, sizeof(altshell), stdin) == NULL) {
776 			altshell[0] = '\0';
777 		} else {
778 			/* nuke \n */
779 			char *p;
780 
781 			if ((p = strchr(altshell, '\n')) != NULL)
782 				*p = '\0';
783 		}
784 
785 		if (altshell[0])
786 			shell = altshell;
787 #endif /* ALTSHELL */
788 
789 		/*
790 		 * Unblock signals.
791 		 * We catch all the interesting ones,
792 		 * and those are reset to SIG_DFL on exec.
793 		 */
794 		(void)sigemptyset(&mask);
795 		(void)sigprocmask(SIG_SETMASK, &mask, NULL);
796 
797 		/*
798 		 * Fire off a shell.
799 		 * If the default one doesn't work, try the Bourne shell.
800 		 */
801 		argv[0] = "-sh";
802 		argv[1] = 0;
803 		(void)setenv("PATH", INIT_PATH, 1);
804 #ifdef ALTSHELL
805 		if (altshell[0])
806 			argv[0] = altshell;
807 		(void)execv(shell, __UNCONST(argv));
808 		emergency("can't exec `%s' for single user: %m", shell);
809 		argv[0] = "-sh";
810 #endif /* ALTSHELL */
811 		(void)execv(INIT_BSHELL, __UNCONST(argv));
812 		emergency("can't exec `%s' for single user: %m", INIT_BSHELL);
813 		(void)sleep(STALL_TIMEOUT);
814 		_exit(3);
815 	}
816 
817 	if (pid == -1) {
818 		/*
819 		 * We are seriously hosed.  Do our best.
820 		 */
821 		emergency("can't fork single-user shell: %m, trying again");
822 		while (waitpid(-1, NULL, WNOHANG) > 0)
823 			continue;
824 		(void)sigaction(SIGTSTP, &satstp, NULL);
825 		(void)sigaction(SIGHUP, &sahup, NULL);
826 		return (state_func_t)single_user;
827 	}
828 
829 	requested_transition = 0;
830 	do {
831 		if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1)
832 			collect_child(wpid, status);
833 		if (wpid == -1) {
834 			if (errno == EINTR)
835 				continue;
836 			warning("wait for single-user shell failed: %m; "
837 			    "restarting");
838 			return (state_func_t)single_user;
839 		}
840 		if (wpid == pid && WIFSTOPPED(status)) {
841 			warning("shell stopped, restarting");
842 			(void)kill(pid, SIGCONT);
843 			wpid = -1;
844 		}
845 	} while (wpid != pid && !requested_transition);
846 
847 	if (requested_transition) {
848 		(void)sigaction(SIGTSTP, &satstp, NULL);
849 		(void)sigaction(SIGHUP, &sahup, NULL);
850 		return (state_func_t)requested_transition;
851 	}
852 
853 	if (WIFSIGNALED(status)) {
854 		if (WTERMSIG(status) == SIGKILL) {
855 			/* executed /sbin/reboot; wait for the end quietly */
856 			sigset_t s;
857 
858 			(void)sigfillset(&s);
859 			for (;;)
860 				(void)sigsuspend(&s);
861 		} else {
862 			warning("single user shell terminated (%x), restarting",
863 				status);
864 			(void)sigaction(SIGTSTP, &satstp, NULL);
865 			(void)sigaction(SIGHUP, &sahup, NULL);
866 			return (state_func_t)single_user;
867 		}
868 	}
869 
870 	runcom_mode = FASTBOOT;
871 	(void)sigaction(SIGTSTP, &satstp, NULL);
872 	(void)sigaction(SIGHUP, &sahup, NULL);
873 #ifndef LETS_GET_SMALL
874 	return (state_func_t)runcom;
875 #else /* LETS_GET_SMALL */
876 	return (state_func_t)single_user;
877 #endif /* LETS_GET_SMALL */
878 }
879 
880 #ifndef LETS_GET_SMALL
881 
882 /* ARGSUSED */
883 static state_func_t
884 runetcrc(int trychroot)
885 {
886 	pid_t pid, wpid;
887 	int status;
888 	const char *argv[4];
889 	struct sigaction sa;
890 
891 	switch ((pid = fork())) {
892 	case 0:
893 		(void)sigemptyset(&sa.sa_mask);
894 		sa.sa_flags = 0;
895 		sa.sa_handler = SIG_IGN;
896 		(void)sigaction(SIGTSTP, &sa, NULL);
897 		(void)sigaction(SIGHUP, &sa, NULL);
898 
899 		setctty(_PATH_CONSOLE);
900 
901 		argv[0] = "sh";
902 		argv[1] = _PATH_RUNCOM;
903 		argv[2] = (runcom_mode == AUTOBOOT ? "autoboot" : 0);
904 		argv[3] = 0;
905 
906 		(void)sigprocmask(SIG_SETMASK, &sa.sa_mask, NULL);
907 
908 #ifdef CHROOT
909 		if (trychroot)
910 			if (chroot(rootdir) != 0) {
911 				warning("failed to chroot to `%s': %m",
912 				    rootdir);
913 				_exit(4); 	/* force single user mode */
914 			}
915 #endif /* CHROOT */
916 
917 		(void)execv(INIT_BSHELL, __UNCONST(argv));
918 		stall("can't exec `%s' for `%s': %m", INIT_BSHELL, _PATH_RUNCOM);
919 		_exit(5);	/* force single user mode */
920 		/*NOTREACHED*/
921 	case -1:
922 		emergency("can't fork for `%s' on `%s': %m", INIT_BSHELL,
923 		    _PATH_RUNCOM);
924 		while (waitpid(-1, NULL, WNOHANG) > 0)
925 			continue;
926 		(void)sleep(STALL_TIMEOUT);
927 		return (state_func_t)single_user;
928 	default:
929 		break;
930 	}
931 
932 	/*
933 	 * Copied from single_user().  This is a bit paranoid.
934 	 */
935 	do {
936 		if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1)
937 			collect_child(wpid, status);
938 		if (wpid == -1) {
939 			if (errno == EINTR)
940 				continue;
941 			warning("wait for `%s' on `%s' failed: %m; going to "
942 			    "single user mode", INIT_BSHELL, _PATH_RUNCOM);
943 			return (state_func_t)single_user;
944 		}
945 		if (wpid == pid && WIFSTOPPED(status)) {
946 			warning("`%s' on `%s' stopped, restarting",
947 			    INIT_BSHELL, _PATH_RUNCOM);
948 			(void)kill(pid, SIGCONT);
949 			wpid = -1;
950 		}
951 	} while (wpid != pid);
952 
953 	if (WIFSIGNALED(status) && WTERMSIG(status) == SIGTERM &&
954 	    requested_transition == catatonia) {
955 		/* /etc/rc executed /sbin/reboot; wait for the end quietly */
956 		sigset_t s;
957 
958 		(void)sigfillset(&s);
959 		for (;;)
960 			(void)sigsuspend(&s);
961 	}
962 
963 	if (!WIFEXITED(status)) {
964 		warning("`%s' on `%s' terminated abnormally, going to "
965 		    "single user mode", INIT_BSHELL, _PATH_RUNCOM);
966 		return (state_func_t)single_user;
967 	}
968 
969 	if (WEXITSTATUS(status))
970 		return (state_func_t)single_user;
971 
972 	return (state_func_t)read_ttys;
973 }
974 
975 /*
976  * Run the system startup script.
977  */
978 static state_func_t
979 runcom(void)
980 {
981 	state_func_t next_step;
982 
983 	/* Run /etc/rc and choose next state depending on the result. */
984 	next_step = runetcrc(0);
985 	if (next_step != (state_func_t)read_ttys)
986 		return (state_func_t)next_step;
987 
988 #ifdef CHROOT
989 	/*
990 	 * If init.root sysctl does not point to "/", we'll chroot and run
991 	 * The Real(tm) /etc/rc now.  Global variable rootdir will tell us
992 	 * where to go.
993 	 */
994 	if (shouldchroot()) {
995 		next_step = runetcrc(1);
996 		if (next_step != (state_func_t)read_ttys)
997 			return (state_func_t)next_step;
998 
999 		did_multiuser_chroot = 1;
1000 	} else {
1001 		did_multiuser_chroot = 0;
1002 	}
1003 #endif /* CHROOT */
1004 
1005 	/*
1006 	 * Regardless of whether in chroot or not, we booted successfuly.
1007 	 * It's time to spawn gettys (ie. next_step's value at this point).
1008 	 */
1009 	runcom_mode = AUTOBOOT;		/* the default */
1010 	/* NB: should send a message to the session logger to avoid blocking. */
1011 #ifdef SUPPORT_UTMPX
1012 	logwtmpx("~", "reboot", "", 0, INIT_PROCESS);
1013 #endif
1014 #ifdef SUPPORT_UTMP
1015 	logwtmp("~", "reboot", "");
1016 #endif
1017 	return (state_func_t)read_ttys;
1018 }
1019 
1020 /*
1021  * Open the session database.
1022  *
1023  * NB: We could pass in the size here; is it necessary?
1024  */
1025 static int
1026 start_session_db(void)
1027 {
1028 
1029 	if (session_db && (*session_db->close)(session_db))
1030 		emergency("session database close: %m");
1031 	if ((session_db = dbopen(NULL, O_RDWR, 0, DB_HASH, NULL)) == 0) {
1032 		emergency("session database open: %m");
1033 		return 1;
1034 	}
1035 	return 0;
1036 
1037 }
1038 
1039 /*
1040  * Add a new login session.
1041  */
1042 static void
1043 add_session(session_t *sp)
1044 {
1045 	DBT key;
1046 	DBT data;
1047 
1048 	if (session_db == NULL)
1049 		return;
1050 
1051 	key.data = &sp->se_process;
1052 	key.size = sizeof sp->se_process;
1053 	data.data = &sp;
1054 	data.size = sizeof sp;
1055 
1056 	if ((*session_db->put)(session_db, &key, &data, 0))
1057 		emergency("insert %d: %m", sp->se_process);
1058 #ifdef SUPPORT_UTMPX
1059 	session_utmpx(sp, 1);
1060 #endif
1061 }
1062 
1063 /*
1064  * Delete an old login session.
1065  */
1066 static void
1067 del_session(session_t *sp)
1068 {
1069 	DBT key;
1070 
1071 	key.data = &sp->se_process;
1072 	key.size = sizeof sp->se_process;
1073 
1074 	if ((*session_db->del)(session_db, &key, 0))
1075 		emergency("delete %d: %m", sp->se_process);
1076 #ifdef SUPPORT_UTMPX
1077 	session_utmpx(sp, 0);
1078 #endif
1079 }
1080 
1081 /*
1082  * Look up a login session by pid.
1083  */
1084 static session_t *
1085 find_session(pid_t pid)
1086 {
1087 	DBT key;
1088 	DBT data;
1089 	session_t *ret;
1090 
1091 	if (session_db == NULL)
1092 		return NULL;
1093 
1094 	key.data = &pid;
1095 	key.size = sizeof pid;
1096 	if ((*session_db->get)(session_db, &key, &data, 0) != 0)
1097 		return 0;
1098 	(void)memmove(&ret, data.data, sizeof(ret));
1099 	return ret;
1100 }
1101 
1102 /*
1103  * Construct an argument vector from a command line.
1104  */
1105 static char **
1106 construct_argv(char *command)
1107 {
1108 	int argc = 0;
1109 	char **argv = malloc(((strlen(command) + 1) / 2 + 1) * sizeof (char *));
1110 	static const char separators[] = " \t";
1111 
1112 	if (argv == NULL)
1113 		return NULL;
1114 
1115 	if ((argv[argc++] = strtok(command, separators)) == 0) {
1116 		free(argv);
1117 		return NULL;
1118 	}
1119 	while ((argv[argc++] = strtok(NULL, separators)) != NULL)
1120 		continue;
1121 	return argv;
1122 }
1123 
1124 /*
1125  * Deallocate a session descriptor.
1126  */
1127 static void
1128 free_session(session_t *sp)
1129 {
1130 
1131 	free(sp->se_device);
1132 	if (sp->se_getty) {
1133 		free(sp->se_getty);
1134 		free(sp->se_getty_argv);
1135 	}
1136 	if (sp->se_window) {
1137 		free(sp->se_window);
1138 		free(sp->se_window_argv);
1139 	}
1140 	free(sp);
1141 }
1142 
1143 /*
1144  * Allocate a new session descriptor.
1145  */
1146 static session_t *
1147 new_session(session_t *sprev, int session_index, struct ttyent *typ)
1148 {
1149 	session_t *sp;
1150 
1151 	if ((typ->ty_status & TTY_ON) == 0 || typ->ty_name == NULL ||
1152 	    typ->ty_getty == NULL)
1153 		return NULL;
1154 
1155 	sp = malloc(sizeof (session_t));
1156 	if (sp == NULL)
1157 		return NULL;
1158 	(void)memset(sp, 0, sizeof *sp);
1159 
1160 	sp->se_flags = SE_PRESENT;
1161 	sp->se_index = session_index;
1162 
1163 	(void)asprintf(&sp->se_device, "%s%s", _PATH_DEV, typ->ty_name);
1164 	if (!sp->se_device) {
1165 		free(sp);
1166 		return NULL;
1167 	}
1168 
1169 	if (setupargv(sp, typ) == 0) {
1170 		free_session(sp);
1171 		return NULL;
1172 	}
1173 
1174 	sp->se_next = NULL;
1175 	if (sprev == NULL) {
1176 		sessions = sp;
1177 		sp->se_prev = NULL;
1178 	} else {
1179 		sprev->se_next = sp;
1180 		sp->se_prev = sprev;
1181 	}
1182 
1183 	return sp;
1184 }
1185 
1186 /*
1187  * Calculate getty and if useful window argv vectors.
1188  */
1189 static int
1190 setupargv(session_t *sp, struct ttyent *typ)
1191 {
1192 
1193 	if (sp->se_getty) {
1194 		free(sp->se_getty);
1195 		free(sp->se_getty_argv);
1196 	}
1197 	(void)asprintf(&sp->se_getty, "%s %s", typ->ty_getty, typ->ty_name);
1198 	if (!sp->se_getty)
1199 		return 0;
1200 	sp->se_getty_argv = construct_argv(sp->se_getty);
1201 	if (sp->se_getty_argv == NULL) {
1202 		warning("can't parse getty for port `%s'", sp->se_device);
1203 		free(sp->se_getty);
1204 		sp->se_getty = NULL;
1205 		return 0;
1206 	}
1207 	if (typ->ty_window) {
1208 		if (sp->se_window)
1209 			free(sp->se_window);
1210 		sp->se_window = strdup(typ->ty_window);
1211 		sp->se_window_argv = construct_argv(sp->se_window);
1212 		if (sp->se_window_argv == NULL) {
1213 			warning("can't parse window for port `%s'",
1214 			    sp->se_device);
1215 			free(sp->se_window);
1216 			sp->se_window = NULL;
1217 			return 0;
1218 		}
1219 	}
1220 	return 1;
1221 }
1222 
1223 /*
1224  * Walk the list of ttys and create sessions for each active line.
1225  */
1226 static state_func_t
1227 read_ttys(void)
1228 {
1229 	int session_index = 0;
1230 	session_t *sp, *snext;
1231 	struct ttyent *typ;
1232 
1233 #ifdef SUPPORT_UTMPX
1234 	if (sessions == NULL) {
1235 		struct stat st;
1236 
1237 		make_utmpx("", BOOT_MSG, BOOT_TIME, 0, &boot_time, 0);
1238 
1239 		/*
1240 		 * If wtmpx is not empty, pick the down time from there
1241 		 */
1242 		if (stat(_PATH_WTMPX, &st) != -1 && st.st_size != 0) {
1243 			struct timeval down_time;
1244 
1245 			TIMESPEC_TO_TIMEVAL(&down_time,
1246 			    st.st_atime > st.st_mtime ?
1247 			    &st.st_atimespec : &st.st_mtimespec);
1248 			make_utmpx("", DOWN_MSG, DOWN_TIME, 0, &down_time, 0);
1249 		}
1250 	}
1251 #endif
1252 	/*
1253 	 * Destroy any previous session state.
1254 	 * There shouldn't be any, but just in case...
1255 	 */
1256 	for (sp = sessions; sp; sp = snext) {
1257 #ifndef LETS_GET_SMALL
1258 		if (sp->se_process)
1259 			clear_session_logs(sp, 0);
1260 #endif
1261 		snext = sp->se_next;
1262 		free_session(sp);
1263 	}
1264 	sessions = NULL;
1265 
1266 	if (start_session_db()) {
1267 		warning("start_session_db failed, death");
1268 #ifdef CHROOT
1269 		/* If /etc/rc ran in chroot, we want to kill any survivors. */
1270 		if (did_multiuser_chroot)
1271 			return (state_func_t)death;
1272 		else
1273 #endif /* CHROOT */
1274 			return (state_func_t)single_user;
1275 	}
1276 
1277 	(void)do_setttyent();
1278 
1279 	/*
1280 	 * Allocate a session entry for each active port.
1281 	 * Note that sp starts at 0.
1282 	 */
1283 	while ((typ = getttyent()) != NULL)
1284 		if ((snext = new_session(sp, ++session_index, typ)) != NULL)
1285 			sp = snext;
1286 	(void)endttyent();
1287 
1288 	return (state_func_t)multi_user;
1289 }
1290 
1291 /*
1292  * Start a window system running.
1293  */
1294 static void
1295 start_window_system(session_t *sp)
1296 {
1297 	pid_t pid;
1298 	sigset_t mask;
1299 
1300 	if ((pid = fork()) == -1) {
1301 		emergency("can't fork for window system on port `%s': %m",
1302 		    sp->se_device);
1303 		/* hope that getty fails and we can try again */
1304 		return;
1305 	}
1306 
1307 	if (pid)
1308 		return;
1309 
1310 	(void)sigemptyset(&mask);
1311 	(void)sigprocmask(SIG_SETMASK, &mask, NULL);
1312 
1313 	if (setsid() < 0)
1314 		emergency("setsid failed (window): %m");
1315 
1316 	(void)execv(sp->se_window_argv[0], sp->se_window_argv);
1317 	stall("can't exec window system `%s' for port `%s': %m",
1318 	    sp->se_window_argv[0], sp->se_device);
1319 	_exit(6);
1320 }
1321 
1322 /*
1323  * Start a login session running.
1324  */
1325 static pid_t
1326 start_getty(session_t *sp)
1327 {
1328 	pid_t pid;
1329 	sigset_t mask;
1330 	time_t current_time = time(NULL);
1331 
1332 	/*
1333 	 * fork(), not vfork() -- we can't afford to block.
1334 	 */
1335 	if ((pid = fork()) == -1) {
1336 		emergency("can't fork for getty on port `%s': %m",
1337 		    sp->se_device);
1338 		return -1;
1339 	}
1340 
1341 	if (pid)
1342 		return pid;
1343 
1344 #ifdef CHROOT
1345 	/* If /etc/rc did proceed inside chroot, we have to try as well. */
1346 	if (did_multiuser_chroot)
1347 		if (chroot(rootdir) != 0) {
1348 			stall("can't chroot getty `%s' inside `%s': %m",
1349 			    sp->se_getty_argv[0], rootdir);
1350 			_exit(7);
1351 		}
1352 #endif /* CHROOT */
1353 
1354 	if (current_time > sp->se_started.tv_sec &&
1355 	    current_time - sp->se_started.tv_sec < GETTY_SPACING) {
1356 		warning("getty repeating too quickly on port `%s', sleeping",
1357 		    sp->se_device);
1358 		(void)sleep(GETTY_SLEEP);
1359 	}
1360 
1361 	if (sp->se_window) {
1362 		start_window_system(sp);
1363 		(void)sleep(WINDOW_WAIT);
1364 	}
1365 
1366 	(void)sigemptyset(&mask);
1367 	(void)sigprocmask(SIG_SETMASK, &mask, (sigset_t *) 0);
1368 
1369 	(void)execv(sp->se_getty_argv[0], sp->se_getty_argv);
1370 	stall("can't exec getty `%s' for port `%s': %m",
1371 	    sp->se_getty_argv[0], sp->se_device);
1372 	_exit(8);
1373 	/*NOTREACHED*/
1374 }
1375 #ifdef SUPPORT_UTMPX
1376 static void
1377 session_utmpx(const session_t *sp, int add)
1378 {
1379 	const char *name = sp->se_getty ? sp->se_getty :
1380 	    (sp->se_window ? sp->se_window : "");
1381 	const char *line = sp->se_device + sizeof(_PATH_DEV) - 1;
1382 
1383 	make_utmpx(name, line, add ? LOGIN_PROCESS : DEAD_PROCESS,
1384 	    sp->se_process, &sp->se_started, sp->se_index);
1385 }
1386 
1387 static void
1388 make_utmpx(const char *name, const char *line, int type, pid_t pid,
1389     const struct timeval *tv, int session)
1390 {
1391 	struct utmpx ut;
1392 	const char *eline;
1393 
1394 	(void)memset(&ut, 0, sizeof(ut));
1395 	(void)strlcpy(ut.ut_name, name, sizeof(ut.ut_name));
1396 	ut.ut_type = type;
1397 	(void)strlcpy(ut.ut_line, line, sizeof(ut.ut_line));
1398 	ut.ut_pid = pid;
1399 	if (tv)
1400 		ut.ut_tv = *tv;
1401 	else
1402 		(void)gettimeofday(&ut.ut_tv, NULL);
1403 	ut.ut_session = session;
1404 
1405 	eline = line + strlen(line);
1406 	if ((size_t)(eline - line) >= sizeof(ut.ut_id))
1407 		line = eline - sizeof(ut.ut_id);
1408 	(void)strncpy(ut.ut_id, line, sizeof(ut.ut_id));
1409 
1410 	if (pututxline(&ut) == NULL)
1411 		warning("can't add utmpx record for `%s': %m", ut.ut_line);
1412 	endutxent();
1413 }
1414 
1415 static char
1416 get_runlevel(const state_t s)
1417 {
1418 	if (s == (state_t)single_user)
1419 		return SINGLE_USER;
1420 	if (s == (state_t)runcom)
1421 		return RUNCOM;
1422 	if (s == (state_t)read_ttys)
1423 		return READ_TTYS;
1424 	if (s == (state_t)multi_user)
1425 		return MULTI_USER;
1426 	if (s == (state_t)clean_ttys)
1427 		return CLEAN_TTYS;
1428 	if (s == (state_t)catatonia)
1429 		return CATATONIA;
1430 	return DEATH;
1431 }
1432 
1433 static void
1434 utmpx_set_runlevel(char old, char new)
1435 {
1436 	struct utmpx ut;
1437 
1438 	/*
1439 	 * Don't record any transitions until we did the first transition
1440 	 * to read ttys, which is when we are guaranteed to have a read-write
1441 	 * /var. Perhaps use a different variable for this?
1442 	 */
1443 	if (sessions == NULL)
1444 		return;
1445 
1446 	(void)memset(&ut, 0, sizeof(ut));
1447 	(void)snprintf(ut.ut_line, sizeof(ut.ut_line), RUNLVL_MSG, new);
1448 	ut.ut_type = RUN_LVL;
1449 	(void)gettimeofday(&ut.ut_tv, NULL);
1450 	ut.ut_exit.e_exit = old;
1451 	ut.ut_exit.e_termination = new;
1452 	if (pututxline(&ut) == NULL)
1453 		warning("can't add utmpx record for `runlevel': %m");
1454 	endutxent();
1455 }
1456 #endif /* SUPPORT_UTMPX */
1457 
1458 #endif /* LETS_GET_SMALL */
1459 
1460 /*
1461  * Collect exit status for a child.
1462  * If an exiting login, start a new login running.
1463  */
1464 static void
1465 collect_child(pid_t pid, int status)
1466 {
1467 #ifndef LETS_GET_SMALL
1468 	session_t *sp, *sprev, *snext;
1469 
1470 	if (! sessions)
1471 		return;
1472 
1473 	if ((sp = find_session(pid)) == NULL)
1474 		return;
1475 
1476 	clear_session_logs(sp, status);
1477 	del_session(sp);
1478 	sp->se_process = 0;
1479 
1480 	if (sp->se_flags & SE_SHUTDOWN) {
1481 		if ((sprev = sp->se_prev) != NULL)
1482 			sprev->se_next = sp->se_next;
1483 		else
1484 			sessions = sp->se_next;
1485 		if ((snext = sp->se_next) != NULL)
1486 			snext->se_prev = sp->se_prev;
1487 		free_session(sp);
1488 		return;
1489 	}
1490 
1491 	if ((pid = start_getty(sp)) == -1) {
1492 		/* serious trouble */
1493 		requested_transition = clean_ttys;
1494 		return;
1495 	}
1496 
1497 	sp->se_process = pid;
1498 	(void)gettimeofday(&sp->se_started, NULL);
1499 	add_session(sp);
1500 #endif /* LETS_GET_SMALL */
1501 }
1502 
1503 /*
1504  * Catch a signal and request a state transition.
1505  */
1506 static void
1507 transition_handler(int sig)
1508 {
1509 
1510 	switch (sig) {
1511 #ifndef LETS_GET_SMALL
1512 	case SIGHUP:
1513 		requested_transition = clean_ttys;
1514 		break;
1515 	case SIGTERM:
1516 		requested_transition = death;
1517 		break;
1518 	case SIGTSTP:
1519 		requested_transition = catatonia;
1520 		break;
1521 #endif /* LETS_GET_SMALL */
1522 	default:
1523 		requested_transition = 0;
1524 		break;
1525 	}
1526 }
1527 
1528 #ifndef LETS_GET_SMALL
1529 /*
1530  * Take the system multiuser.
1531  */
1532 static state_func_t
1533 multi_user(void)
1534 {
1535 	pid_t pid;
1536 	int status;
1537 	session_t *sp;
1538 
1539 	requested_transition = 0;
1540 
1541 	/*
1542 	 * If the administrator has not set the security level to -1
1543 	 * to indicate that the kernel should not run multiuser in secure
1544 	 * mode, and the run script has not set a higher level of security
1545 	 * than level 1, then put the kernel into secure mode.
1546 	 */
1547 	if (getsecuritylevel() == 0)
1548 		setsecuritylevel(1);
1549 
1550 	for (sp = sessions; sp; sp = sp->se_next) {
1551 		if (sp->se_process)
1552 			continue;
1553 		if ((pid = start_getty(sp)) == -1) {
1554 			/* serious trouble */
1555 			requested_transition = clean_ttys;
1556 			break;
1557 		}
1558 		sp->se_process = pid;
1559 		(void)gettimeofday(&sp->se_started, NULL);
1560 		add_session(sp);
1561 	}
1562 
1563 	while (!requested_transition)
1564 		if ((pid = waitpid(-1, &status, 0)) != -1)
1565 			collect_child(pid, status);
1566 
1567 	return (state_func_t)requested_transition;
1568 }
1569 
1570 /*
1571  * This is an n-squared algorithm.  We hope it isn't run often...
1572  */
1573 static state_func_t
1574 clean_ttys(void)
1575 {
1576 	session_t *sp, *sprev;
1577 	struct ttyent *typ;
1578 	int session_index = 0;
1579 	int devlen;
1580 
1581 	for (sp = sessions; sp; sp = sp->se_next)
1582 		sp->se_flags &= ~SE_PRESENT;
1583 
1584 	(void)do_setttyent();
1585 
1586 	devlen = sizeof(_PATH_DEV) - 1;
1587 	while ((typ = getttyent()) != NULL) {
1588 		++session_index;
1589 
1590 		for (sprev = 0, sp = sessions; sp; sprev = sp, sp = sp->se_next)
1591 			if (strcmp(typ->ty_name, sp->se_device + devlen) == 0)
1592 				break;
1593 
1594 		if (sp) {
1595 			sp->se_flags |= SE_PRESENT;
1596 			if (sp->se_index != session_index) {
1597 				warning("port `%s' changed utmp index from "
1598 				    "%d to %d", sp->se_device, sp->se_index,
1599 				    session_index);
1600 				sp->se_index = session_index;
1601 			}
1602 			if ((typ->ty_status & TTY_ON) == 0 ||
1603 			    typ->ty_getty == 0) {
1604 				sp->se_flags |= SE_SHUTDOWN;
1605 				if (sp->se_process != 0)
1606 					(void)kill(sp->se_process, SIGHUP);
1607 				continue;
1608 			}
1609 			sp->se_flags &= ~SE_SHUTDOWN;
1610 			if (setupargv(sp, typ) == 0) {
1611 				warning("can't parse getty for port `%s'",
1612 				    sp->se_device);
1613 				sp->se_flags |= SE_SHUTDOWN;
1614 				if (sp->se_process != 0)
1615 					(void)kill(sp->se_process, SIGHUP);
1616 			}
1617 			continue;
1618 		}
1619 
1620 		(void)new_session(sprev, session_index, typ);
1621 	}
1622 
1623 	(void)endttyent();
1624 
1625 	for (sp = sessions; sp; sp = sp->se_next)
1626 		if ((sp->se_flags & SE_PRESENT) == 0) {
1627 			sp->se_flags |= SE_SHUTDOWN;
1628 			if (sp->se_process != 0)
1629 				(void)kill(sp->se_process, SIGHUP);
1630 		}
1631 
1632 	return (state_func_t)multi_user;
1633 }
1634 
1635 /*
1636  * Block further logins.
1637  */
1638 static state_func_t
1639 catatonia(void)
1640 {
1641 	session_t *sp;
1642 
1643 	for (sp = sessions; sp; sp = sp->se_next)
1644 		sp->se_flags |= SE_SHUTDOWN;
1645 
1646 	return (state_func_t)multi_user;
1647 }
1648 #endif /* LETS_GET_SMALL */
1649 
1650 /*
1651  * Note SIGALRM.
1652  */
1653 static void
1654 /*ARGSUSED*/
1655 alrm_handler(int sig)
1656 {
1657 
1658 	clang = 1;
1659 }
1660 
1661 #ifndef LETS_GET_SMALL
1662 /*
1663  * Bring the system down to single user.
1664  */
1665 static state_func_t
1666 death(void)
1667 {
1668 	session_t *sp;
1669 	int i, status;
1670 	pid_t pid;
1671 	static const int death_sigs[3] = { SIGHUP, SIGTERM, SIGKILL };
1672 
1673 	for (sp = sessions; sp; sp = sp->se_next)
1674 		sp->se_flags |= SE_SHUTDOWN;
1675 
1676 	/* NB: should send a message to the session logger to avoid blocking. */
1677 #ifdef SUPPORT_UTMPX
1678 	logwtmpx("~", "shutdown", "", 0, INIT_PROCESS);
1679 #endif
1680 #ifdef SUPPORT_UTMP
1681 	logwtmp("~", "shutdown", "");
1682 #endif
1683 
1684 	for (i = 0; i < 3; ++i) {
1685 		if (kill(-1, death_sigs[i]) == -1 && errno == ESRCH)
1686 			return (state_func_t)single_user;
1687 
1688 		clang = 0;
1689 		(void)alarm(DEATH_WATCH);
1690 		do
1691 			if ((pid = waitpid(-1, &status, 0)) != -1)
1692 				collect_child(pid, status);
1693 		while (clang == 0 && errno != ECHILD);
1694 
1695 		if (errno == ECHILD)
1696 			return (state_func_t)single_user;
1697 	}
1698 
1699 	warning("some processes would not die; ps axl advised");
1700 
1701 	return (state_func_t)single_user;
1702 }
1703 #endif /* LETS_GET_SMALL */
1704 
1705 #ifdef MFS_DEV_IF_NO_CONSOLE
1706 
1707 static int
1708 mfs_dev(void)
1709 {
1710 	/*
1711 	 * We cannot print errors so we bail out silently...
1712 	 */
1713 	pid_t pid;
1714 	int status;
1715 
1716 	/* If we have /dev/console, assume all is OK  */
1717 	if (access(_PATH_CONSOLE, F_OK) == 0)
1718 		return 0;
1719 
1720 #if 0	/* Useful for testing MAKEDEV */
1721 	/* Mount an mfs over /mnt so we can create a console entry */
1722 	switch ((pid = fork())) {
1723 	case 0:
1724 		(void)execl(INIT_MOUNT_MFS, "mount_mfs",
1725 		    "-b", "4096", "-f", "512",
1726 		    "-s", 64, "-n", 10,
1727 		    "-p", "0755",
1728 		    "swap", "/mnt", NULL);
1729 		_exit(9);
1730 		/*NOTREACHED*/
1731 
1732 	case -1:
1733 		return(-1);
1734 
1735 	default:
1736 		if (waitpid(pid, &status, 0) == -1)
1737 			return(-1);
1738 		if (status != 0)
1739 			return(-1);
1740 		break;
1741 	}
1742 
1743 	{
1744 		dev_t dev;
1745 #ifdef CPU_CONSDEV
1746 		static int name[2] = { CTL_MACHDEP, CPU_CONSDEV };
1747 		size_t olen;
1748 		olen = sizeof(dev);
1749 		if (sysctl(name, sizeof(name) / sizeof(name[0]), &dev, &olen,
1750 		    NULL, 0) == -1)
1751 #endif
1752 			dev = makedev(0, 0);
1753 
1754 		/* Make a console for us, so we can see things happening */
1755 		if (mknod("/mnt/console", 0666 | S_IFCHR, dev) == -1)
1756 			return(-1);
1757 		(void)freopen("/mnt/console", "a", stderr);
1758 	}
1759 
1760 #endif
1761 
1762 	/* Run the makedev script to create devices */
1763 	switch ((pid = fork())) {
1764 	case 0:
1765 		(void)dup2(2, 1);	/* Give the script stdout */
1766 		if (chdir("/dev") == 0)
1767 			(void)execl(INIT_BSHELL, "sh",
1768 			    access("./MAKEDEV", X_OK) == 0
1769 				? "./MAKEDEV" : "/etc/MAKEDEV",
1770 			    "-MM", "init", NULL);
1771 		_exit(10);
1772 		/* NOTREACHED */
1773 
1774 	case -1:
1775 		break;
1776 
1777 	default:
1778 		if (waitpid(pid, &status, 0) == -1)
1779 			break;
1780 		if (status != 0)
1781 			warn("MAKEDEV exit status %d\n", status);
1782 		/*
1783 		 * If /dev/console got created, then return 0
1784 		 * regardless of MAKEDEV exit status.
1785 		 */
1786 		if (access(_PATH_CONSOLE, F_OK) == 0)
1787 			return 0;
1788 		_exit(11);
1789 	}
1790 	warn("Unable to run MAKEDEV");
1791 	_exit(12);
1792 }
1793 #endif
1794 
1795 #ifndef LETS_GET_SMALL
1796 static int
1797 do_setttyent(void)
1798 {
1799 	(void)endttyent();
1800 #ifdef CHROOT
1801 	if (did_multiuser_chroot) {
1802 		char path[PATH_MAX];
1803 
1804 		(void)snprintf(path, sizeof(path), "%s/%s", rootdir, _PATH_TTYS);
1805 
1806 		return setttyentpath(path);
1807 	} else
1808 #endif /* CHROOT */
1809 		return setttyent();
1810 }
1811 #endif
1812 
1813 #if !defined(LETS_GET_SMALL) && defined(CHROOT)
1814 
1815 static int
1816 createsysctlnode(void)
1817 {
1818 #if !defined(__minix)
1819 	struct sysctlnode node;
1820 	int mib[2];
1821 	size_t len;
1822 
1823 	/*
1824 	 * Create top-level dynamic sysctl node.  Its child nodes will only
1825 	 * be readable by the superuser, since regular mortals should not
1826 	 * care ("Sssh, it's a secret!").
1827 	 */
1828 	len = sizeof(struct sysctlnode);
1829 	mib[0] = CTL_CREATE;
1830 
1831 	(void)memset(&node, 0, len);
1832 	node.sysctl_flags = SYSCTL_VERSION | CTLFLAG_READWRITE |
1833 	    CTLFLAG_PRIVATE | CTLTYPE_NODE;
1834 	node.sysctl_num = CTL_CREATE;
1835 	(void)snprintf(node.sysctl_name, SYSCTL_NAMELEN, "init");
1836 	if (sysctl(&mib[0], 1, &node, &len, &node, len) == -1) {
1837 		warning("could not create init node: %m");
1838 		return -1;
1839 	}
1840 
1841 	/*
1842 	 * Create second level dynamic node capable of holding pathname.
1843 	 * Provide "/" as the default value.
1844 	 */
1845 	len = sizeof(struct sysctlnode);
1846 	mib[0] = node.sysctl_num;
1847 	mib[1] = CTL_CREATE;
1848 
1849 	(void)memset(&node, 0, len);
1850 	node.sysctl_flags = SYSCTL_VERSION | CTLFLAG_READWRITE |
1851 	    CTLTYPE_STRING | CTLFLAG_OWNDATA;
1852 	node.sysctl_size = _POSIX_PATH_MAX;
1853 	node.sysctl_data = __UNCONST("/");
1854 	node.sysctl_num = CTL_CREATE;
1855 	(void)snprintf(node.sysctl_name, SYSCTL_NAMELEN, "root");
1856 	if (sysctl(&mib[0], 2, NULL, NULL, &node, len) == -1) {
1857 		warning("could not create init.root node: %m");
1858 		return -1;
1859 	}
1860 #endif /* !defined(__minix) */
1861 
1862 	return 0;
1863 }
1864 
1865 static int
1866 shouldchroot(void)
1867 {
1868 #if !defined(__minix)
1869 	struct sysctlnode node;
1870 	size_t len, cnt;
1871 	int mib;
1872 
1873 	len = sizeof(struct sysctlnode);
1874 
1875 	if (sysctlbyname("init.root", rootdir, &len, NULL, 0) == -1) {
1876 		warning("could not read init.root: %m");
1877 
1878 		/* Child killed our node. Recreate it. */
1879 		if (errno == ENOENT) {
1880 			/* Destroy whatever is left, recreate from scratch. */
1881 			if (sysctlnametomib("init", &mib, &cnt) != -1) {
1882 				(void)memset(&node, 0, sizeof(node));
1883 				node.sysctl_flags = SYSCTL_VERSION;
1884 				node.sysctl_num = mib;
1885 				mib = CTL_DESTROY;
1886 
1887 				(void)sysctl(&mib, 1, NULL, NULL, &node,
1888 				    sizeof(node));
1889 			}
1890 
1891 			(void)createsysctlnode();
1892 		}
1893 
1894 		/* We certainly won't chroot. */
1895 		return 0;
1896 	}
1897 
1898 	if (rootdir[len] != '\0' || strlen(rootdir) != len - 1) {
1899 		warning("init.root is not a string");
1900 		return 0;
1901 	}
1902 
1903 	if (strcmp(rootdir, "/") == 0)
1904 		return 0;
1905 
1906 	return 1;
1907 #else
1908 	return 0;
1909 #endif /* !defined(__minix) */
1910 }
1911 
1912 #endif /* !LETS_GET_SMALL && CHROOT */
1913