xref: /netbsd-src/sbin/init/init.c (revision d48f14661dda8638fee055ba15d35bdfb29b9fa8)
1 /*	$NetBSD: init.c,v 1.73 2006/04/18 11:40:26 salo 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\n"
38 "	The Regents of the University of California.  All rights reserved.\n");
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 1.73 2006/04/18 11:40:26 salo 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 <sys/sysctl.h>
56 #include <machine/cpu.h>
57 
58 #include <db.h>
59 #include <errno.h>
60 #include <fcntl.h>
61 #include <signal.h>
62 #include <stdio.h>
63 #include <stdlib.h>
64 #include <string.h>
65 #include <syslog.h>
66 #include <time.h>
67 #include <ttyent.h>
68 #include <unistd.h>
69 #include <util.h>
70 #include <paths.h>
71 #include <err.h>
72 
73 #include <stdarg.h>
74 
75 #ifdef SECURE
76 #include <pwd.h>
77 #endif
78 
79 #include "pathnames.h"
80 
81 #define XSTR(x) #x
82 #define STR(x) XSTR(x)
83 
84 /*
85  * Sleep times; used to prevent thrashing.
86  */
87 #define	GETTY_SPACING		 5	/* N secs minimum getty spacing */
88 #define	GETTY_SLEEP		30	/* sleep N secs after spacing problem */
89 #define	WINDOW_WAIT		 3	/* wait N secs after starting window */
90 #define	STALL_TIMEOUT		30	/* wait N secs after warning */
91 #define	DEATH_WATCH		10	/* wait N secs for procs to die */
92 
93 const struct timespec dtrtime = {.tv_sec = 0, .tv_nsec = 250000};
94 
95 #if defined(RESCUEDIR)
96 #define	INIT_BSHELL	RESCUEDIR "/sh"
97 #define	INIT_MOUNT_MFS	RESCUEDIR "/mount_mfs"
98 #define	INIT_PATH	RESCUEDIR ":" _PATH_STDPATH
99 #else
100 #define	INIT_BSHELL	_PATH_BSHELL
101 #define	INIT_MOUNT_MFS	"/sbin/mount_mfs"
102 #define	INIT_PATH	_PATH_STDPATH
103 #endif
104 
105 int main(int, char *[]);
106 
107 void handle(sig_t, ...);
108 void delset(sigset_t *, ...);
109 
110 void stall(const char *, ...)
111     __attribute__((__format__(__printf__,1,2)));
112 void warning(const char *, ...)
113     __attribute__((__format__(__printf__,1,2)));
114 void emergency(const char *, ...)
115     __attribute__((__format__(__printf__,1,2)));
116 void disaster(int);
117 void badsys(int);
118 
119 /*
120  * We really need a recursive typedef...
121  * The following at least guarantees that the return type of (*state_t)()
122  * is sufficiently wide to hold a function pointer.
123  */
124 typedef long (*state_func_t)(void);
125 typedef state_func_t (*state_t)(void);
126 
127 state_func_t single_user(void);
128 state_func_t runcom(void);
129 state_func_t read_ttys(void);
130 state_func_t multi_user(void);
131 state_func_t clean_ttys(void);
132 state_func_t catatonia(void);
133 state_func_t death(void);
134 
135 enum { AUTOBOOT, FASTBOOT } runcom_mode = AUTOBOOT;
136 
137 void transition(state_t);
138 void setctty(const char *);
139 
140 typedef struct init_session {
141 	int	se_index;		/* index of entry in ttys file */
142 	pid_t	se_process;		/* controlling process */
143 	time_t	se_started;		/* used to avoid thrashing */
144 	int	se_flags;		/* status of session */
145 #define	SE_SHUTDOWN	0x1		/* session won't be restarted */
146 #define	SE_PRESENT	0x2		/* session is in /etc/ttys */
147 	char	*se_device;		/* filename of port */
148 	char	*se_getty;		/* what to run on that port */
149 	char	**se_getty_argv;	/* pre-parsed argument array */
150 	char	*se_window;		/* window system (started only once) */
151 	char	**se_window_argv;	/* pre-parsed argument array */
152 	struct	init_session *se_prev;
153 	struct	init_session *se_next;
154 } session_t;
155 
156 void free_session(session_t *);
157 session_t *new_session(session_t *, int, struct ttyent *);
158 session_t *sessions;
159 
160 char **construct_argv(char *);
161 void start_window_system(session_t *);
162 void collect_child(pid_t, int);
163 pid_t start_getty(session_t *);
164 void transition_handler(int);
165 void alrm_handler(int);
166 void setsecuritylevel(int);
167 int getsecuritylevel(void);
168 int setupargv(session_t *, struct ttyent *);
169 int clang;
170 
171 int start_session_db(void);
172 void add_session(session_t *);
173 void del_session(session_t *);
174 session_t *find_session(pid_t);
175 DB *session_db;
176 
177 int do_setttyent(void);
178 
179 #ifndef LETS_GET_SMALL
180 state_t requested_transition = runcom;
181 
182 void clear_session_logs(session_t *, int);
183 state_func_t runetcrc(int);
184 
185 #ifdef CHROOT
186 int did_multiuser_chroot = 0;
187 char rootdir[PATH_MAX];
188 int shouldchroot(void);
189 int createsysctlnode(void);
190 #endif /* CHROOT */
191 
192 #else /* LETS_GET_SMALL */
193 state_t requested_transition = single_user;
194 #endif /* !LETS_GET_SMALL */
195 
196 #ifdef MFS_DEV_IF_NO_CONSOLE
197 
198 #define NINODE 1024
199 #define FSSIZE ((8192		/* boot area */				\
200 	+ 2 * 8192		/* two copies of superblock */		\
201 	+ 4096			/* cylinder group info */		\
202 	+ NINODE * (128 + 18)	/* inode and directory entry */		\
203 	+ mfile[0].len		/* size of MAKEDEV file */		\
204 	+ 2 * 4096) / 512)	/* some slack */
205 
206 struct mappedfile {
207 	const char *path;
208 	char	*buf;
209 	int	len;
210 } mfile[] = {
211 	{ "/dev/MAKEDEV",	NULL,	0 },
212 	{ "/dev/MAKEDEV.local",	NULL,	0 }
213 };
214 
215 static int mfs_dev(void);
216 static void mapfile(struct mappedfile *);
217 static void writefile(struct mappedfile *);
218 
219 #endif
220 
221 /*
222  * The mother of all processes.
223  */
224 int
225 main(int argc, char **argv)
226 {
227 	struct sigaction sa;
228 	sigset_t mask;
229 #ifndef LETS_GET_SMALL
230 	int c;
231 
232 	/* Dispose of random users. */
233 	if (getuid() != 0) {
234 		errno = EPERM;
235 		err(1, NULL);
236 	}
237 
238 	/* System V users like to reexec init. */
239 	if (getpid() != 1)
240 		errx(1, "already running");
241 #endif
242 
243 	/*
244 	 * Create an initial session.
245 	 */
246 	if (setsid() < 0)
247 		warn("initial setsid() failed");
248 
249 	/*
250 	 * Establish an initial user so that programs running
251 	 * single user do not freak out and die (like passwd).
252 	 */
253 	if (setlogin("root") < 0)
254 		warn("setlogin() failed");
255 
256 
257 #ifdef MFS_DEV_IF_NO_CONSOLE
258 	if (mfs_dev() == -1)
259 		requested_transition = single_user;
260 #endif
261 
262 #ifndef LETS_GET_SMALL
263 	/*
264 	 * Note that this does NOT open a file...
265 	 * Does 'init' deserve its own facility number?
266 	 */
267 	openlog("init", LOG_CONS, LOG_AUTH);
268 #endif /* LETS_GET_SMALL */
269 
270 
271 #ifndef LETS_GET_SMALL
272 	/*
273 	 * This code assumes that we always get arguments through flags,
274 	 * never through bits set in some random machine register.
275 	 */
276 	while ((c = getopt(argc, argv, "sf")) != -1)
277 		switch (c) {
278 		case 's':
279 			requested_transition = single_user;
280 			break;
281 		case 'f':
282 			runcom_mode = FASTBOOT;
283 			break;
284 		default:
285 			warning("unrecognized flag '-%c'", c);
286 			break;
287 		}
288 
289 	if (optind != argc)
290 		warning("ignoring excess arguments");
291 #else /* LETS_GET_SMALL */
292 	requested_transition = single_user;
293 #endif /* LETS_GET_SMALL */
294 
295 	/*
296 	 * We catch or block signals rather than ignore them,
297 	 * so that they get reset on exec.
298 	 */
299 	handle(badsys, SIGSYS, 0);
300 	handle(disaster, SIGABRT, SIGFPE, SIGILL, SIGSEGV,
301 	       SIGBUS, SIGXCPU, SIGXFSZ, 0);
302 	handle(transition_handler, SIGHUP, SIGTERM, SIGTSTP, 0);
303 	handle(alrm_handler, SIGALRM, 0);
304 	(void)sigfillset(&mask);
305 	delset(&mask, SIGABRT, SIGFPE, SIGILL, SIGSEGV, SIGBUS, SIGSYS,
306 	    SIGXCPU, SIGXFSZ, SIGHUP, SIGTERM, SIGTSTP, SIGALRM, 0);
307 	(void)sigprocmask(SIG_SETMASK, &mask, NULL);
308 	(void)sigemptyset(&sa.sa_mask);
309 	sa.sa_flags = 0;
310 	sa.sa_handler = SIG_IGN;
311 	(void)sigaction(SIGTTIN, &sa, NULL);
312 	(void)sigaction(SIGTTOU, &sa, NULL);
313 
314 	/*
315 	 * Paranoia.
316 	 */
317 	(void)close(0);
318 	(void)close(1);
319 	(void)close(2);
320 
321 #if !defined(LETS_GET_SMALL) && defined(CHROOT)
322 	/* Create "init.root" sysctl node. */
323 	createsysctlnode();
324 #endif /* !LETS_GET_SMALL && CHROOT*/
325 
326 	/*
327 	 * Start the state machine.
328 	 */
329 	transition(requested_transition);
330 
331 	/*
332 	 * Should never reach here.
333 	 */
334 	return 1;
335 }
336 
337 /*
338  * Associate a function with a signal handler.
339  */
340 void
341 handle(sig_t handler, ...)
342 {
343 	int sig;
344 	struct sigaction sa;
345 	sigset_t mask_everything;
346 	va_list ap;
347 
348 	va_start(ap, handler);
349 
350 	sa.sa_handler = handler;
351 	(void)sigfillset(&mask_everything);
352 
353 	while ((sig = va_arg(ap, int)) != 0) {
354 		sa.sa_mask = mask_everything;
355 		/* XXX SA_RESTART? */
356 		sa.sa_flags = sig == SIGCHLD ? SA_NOCLDSTOP : 0;
357 		(void)sigaction(sig, &sa, NULL);
358 	}
359 	va_end(ap);
360 }
361 
362 /*
363  * Delete a set of signals from a mask.
364  */
365 void
366 delset(sigset_t *maskp, ...)
367 {
368 	int sig;
369 	va_list ap;
370 
371 	va_start(ap, maskp);
372 
373 	while ((sig = va_arg(ap, int)) != 0)
374 		(void)sigdelset(maskp, sig);
375 	va_end(ap);
376 }
377 
378 /*
379  * Log a message and sleep for a while (to give someone an opportunity
380  * to read it and to save log or hardcopy output if the problem is chronic).
381  * NB: should send a message to the session logger to avoid blocking.
382  */
383 void
384 stall(const char *message, ...)
385 {
386 	va_list ap;
387 
388 	va_start(ap, message);
389 	vsyslog(LOG_ALERT, message, ap);
390 	va_end(ap);
391 	closelog();
392 	(void)sleep(STALL_TIMEOUT);
393 }
394 
395 /*
396  * Like stall(), but doesn't sleep.
397  * If cpp had variadic macros, the two functions could be #defines for another.
398  * NB: should send a message to the session logger to avoid blocking.
399  */
400 void
401 warning(const char *message, ...)
402 {
403 	va_list ap;
404 
405 	va_start(ap, message);
406 	vsyslog(LOG_ALERT, message, ap);
407 	va_end(ap);
408 	closelog();
409 
410 #if 0
411 	/*
412 	 * XXX: syslog seems to just plain not work in console-only
413 	 * XXX: situation... that should be fixed.  Let's leave this
414 	 * XXX: note + code here in case someone gets in trouble and
415 	 * XXX: wants to debug. -- Jachym Holecek <freza@liberouter.org>
416 	 */
417 	{
418 		char errbuf[1024];
419 		int fd, len;
420 
421 		/* We can't do anything on errors, anyway... */
422 		fd = open(_PATH_CONSOLE, O_WRONLY);
423 		if (fd == -1)
424 			return ;
425 
426 		/* %m will get lost... */
427 		len = vsnprintf(errbuf, sizeof(errbuf), message, ap);
428 		(void)write(fd, (void *)errbuf, len);
429 		(void)close(fd);
430 	}
431 #endif
432 }
433 
434 /*
435  * Log an emergency message.
436  * NB: should send a message to the session logger to avoid blocking.
437  */
438 void
439 emergency(const char *message, ...)
440 {
441 	va_list ap;
442 
443 	va_start(ap, message);
444 	vsyslog(LOG_EMERG, message, ap);
445 	va_end(ap);
446 	closelog();
447 }
448 
449 /*
450  * Catch a SIGSYS signal.
451  *
452  * These may arise if a system does not support sysctl.
453  * We tolerate up to 25 of these, then throw in the towel.
454  */
455 void
456 badsys(int sig)
457 {
458 	static int badcount = 0;
459 
460 	if (badcount++ < 25)
461 		return;
462 	disaster(sig);
463 }
464 
465 /*
466  * Catch an unexpected signal.
467  */
468 void
469 disaster(int sig)
470 {
471 
472 	emergency("fatal signal: %s", strsignal(sig));
473 	(void)sleep(STALL_TIMEOUT);
474 	_exit(sig);		/* reboot */
475 }
476 
477 /*
478  * Get the security level of the kernel.
479  */
480 int
481 getsecuritylevel(void)
482 {
483 #ifdef KERN_SECURELVL
484 	int name[2], curlevel;
485 	size_t len;
486 
487 	name[0] = CTL_KERN;
488 	name[1] = KERN_SECURELVL;
489 	len = sizeof curlevel;
490 	if (sysctl(name, 2, &curlevel, &len, NULL, 0) == -1) {
491 		emergency("cannot get kernel security level: %m");
492 		return (-1);
493 	}
494 	return (curlevel);
495 #else
496 	return (-1);
497 #endif
498 }
499 
500 /*
501  * Set the security level of the kernel.
502  */
503 void
504 setsecuritylevel(int newlevel)
505 {
506 #ifdef KERN_SECURELVL
507 	int name[2], curlevel;
508 
509 	curlevel = getsecuritylevel();
510 	if (newlevel == curlevel)
511 		return;
512 	name[0] = CTL_KERN;
513 	name[1] = KERN_SECURELVL;
514 	if (sysctl(name, 2, NULL, NULL, &newlevel, sizeof newlevel) == -1) {
515 		emergency( "cannot change kernel security level from"
516 		    " %d to %d: %m", curlevel, newlevel);
517 		return;
518 	}
519 #ifdef SECURE
520 	warning("kernel security level changed from %d to %d",
521 	    curlevel, newlevel);
522 #endif
523 #endif
524 }
525 
526 /*
527  * Change states in the finite state machine.
528  * The initial state is passed as an argument.
529  */
530 void
531 transition(state_t s)
532 {
533 
534 	if (s == NULL)
535 		return;
536 	for (;;)
537 		s = (state_t)(*s)();
538 }
539 
540 #ifndef LETS_GET_SMALL
541 /*
542  * Close out the accounting files for a login session.
543  * NB: should send a message to the session logger to avoid blocking.
544  */
545 void
546 clear_session_logs(session_t *sp, int status)
547 {
548 	char *line = sp->se_device + sizeof(_PATH_DEV) - 1;
549 
550 #ifdef SUPPORT_UTMPX
551 	if (logoutx(line, status, DEAD_PROCESS))
552 		logwtmpx(line, "", "", status, DEAD_PROCESS);
553 #endif
554 #ifdef SUPPORT_UTMP
555 	if (logout(line))
556 		logwtmp(line, "", "");
557 #endif
558 }
559 #endif
560 
561 /*
562  * Start a session and allocate a controlling terminal.
563  * Only called by children of init after forking.
564  */
565 void
566 setctty(const char *name)
567 {
568 	int fd;
569 
570 	(void) revoke(name);
571 	nanosleep(&dtrtime, NULL);	/* leave DTR low for a bit */
572 	if ((fd = open(name, O_RDWR)) == -1) {
573 		stall("can't open %s: %m", name);
574 		_exit(1);
575 	}
576 	if (login_tty(fd) == -1) {
577 		stall("can't get %s for controlling terminal: %m", name);
578 		_exit(1);
579 	}
580 }
581 
582 /*
583  * Bring the system up single user.
584  */
585 state_func_t
586 single_user(void)
587 {
588 	pid_t pid, wpid;
589 	int status;
590 	int from_securitylevel;
591 	sigset_t mask;
592 	struct sigaction sa, satstp, sahup;
593 #ifdef ALTSHELL
594 	const char *shell = INIT_BSHELL;
595 #endif
596 	const char *argv[2];
597 #ifdef SECURE
598 	struct ttyent *typ;
599 	struct passwd *pp;
600 	char *clear, *password;
601 #endif
602 #ifdef ALTSHELL
603 	char altshell[128];
604 #endif /* ALTSHELL */
605 
606 #if !defined(LETS_GET_SMALL) && defined(CHROOT)
607 	/* Clear previous idea, just in case. */
608 	did_multiuser_chroot = 0;
609 #endif /* !LETS_GET_SMALL && CHROOT */
610 
611 	/*
612 	 * If the kernel is in secure mode, downgrade it to insecure mode.
613 	 */
614 	from_securitylevel = getsecuritylevel();
615 	if (from_securitylevel > 0)
616 		setsecuritylevel(0);
617 
618 	(void)sigemptyset(&sa.sa_mask);
619 	sa.sa_flags = 0;
620 	sa.sa_handler = SIG_IGN;
621 	(void)sigaction(SIGTSTP, &sa, &satstp);
622 	(void)sigaction(SIGHUP, &sa, &sahup);
623 	if ((pid = fork()) == 0) {
624 		/*
625 		 * Start the single user session.
626 		 */
627 		if (access(_PATH_CONSTTY, F_OK) == 0)
628 			setctty(_PATH_CONSTTY);
629 		else
630 			setctty(_PATH_CONSOLE);
631 
632 #ifdef SECURE
633 		/*
634 		 * Check the root password.
635 		 * We don't care if the console is 'on' by default;
636 		 * it's the only tty that can be 'off' and 'secure'.
637 		 */
638 		typ = getttynam("console");
639 		pp = getpwnam("root");
640 		if (typ && (from_securitylevel >=2 || (typ->ty_status
641 		    & TTY_SECURE) == 0) && pp && *pp->pw_passwd != '\0') {
642 			(void)fprintf(stderr,
643 			    "Enter root password, or ^D to go multi-user\n");
644 			for (;;) {
645 				clear = getpass("Password:");
646 				if (clear == 0 || *clear == '\0')
647 					_exit(0);
648 				password = crypt(clear, pp->pw_passwd);
649 				(void)memset(clear, 0, _PASSWORD_LEN);
650 				if (strcmp(password, pp->pw_passwd) == 0)
651 					break;
652 				warning("single-user login failed\n");
653 			}
654 		}
655 		endttyent();
656 		endpwent();
657 #endif /* SECURE */
658 
659 #ifdef ALTSHELL
660 		(void)fprintf(stderr,
661 		    "Enter pathname of shell or RETURN for %s: ", shell);
662 		if (fgets(altshell, sizeof(altshell), stdin) == NULL) {
663 			altshell[0] = '\0';
664 		} else {
665 			/* nuke \n */
666 			char *p;
667 
668 			if ((p = strchr(altshell, '\n')) != NULL)
669 				*p = '\0';
670 		}
671 
672 		if (altshell[0])
673 			shell = altshell;
674 #endif /* ALTSHELL */
675 
676 		/*
677 		 * Unblock signals.
678 		 * We catch all the interesting ones,
679 		 * and those are reset to SIG_DFL on exec.
680 		 */
681 		(void)sigemptyset(&mask);
682 		(void)sigprocmask(SIG_SETMASK, &mask, NULL);
683 
684 		/*
685 		 * Fire off a shell.
686 		 * If the default one doesn't work, try the Bourne shell.
687 		 */
688 		argv[0] = "-sh";
689 		argv[1] = 0;
690 		setenv("PATH", INIT_PATH, 1);
691 #ifdef ALTSHELL
692 		if (altshell[0])
693 			argv[0] = altshell;
694 		(void)execv(shell, __UNCONST(argv));
695 		emergency("can't exec %s for single user: %m", shell);
696 		argv[0] = "-sh";
697 #endif /* ALTSHELL */
698 		(void)execv(INIT_BSHELL, __UNCONST(argv));
699 		emergency("can't exec %s for single user: %m", INIT_BSHELL);
700 		(void)sleep(STALL_TIMEOUT);
701 		_exit(1);
702 	}
703 
704 	if (pid == -1) {
705 		/*
706 		 * We are seriously hosed.  Do our best.
707 		 */
708 		emergency("can't fork single-user shell, trying again");
709 		while (waitpid(-1, NULL, WNOHANG) > 0)
710 			continue;
711 		(void)sigaction(SIGTSTP, &satstp, NULL);
712 		(void)sigaction(SIGHUP, &sahup, NULL);
713 		return (state_func_t) single_user;
714 	}
715 
716 	requested_transition = 0;
717 	do {
718 		if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1)
719 			collect_child(wpid, status);
720 		if (wpid == -1) {
721 			if (errno == EINTR)
722 				continue;
723 			warning("wait for single-user shell failed: %m; "
724 			    "restarting");
725 			return (state_func_t)single_user;
726 		}
727 		if (wpid == pid && WIFSTOPPED(status)) {
728 			warning("init: shell stopped, restarting\n");
729 			kill(pid, SIGCONT);
730 			wpid = -1;
731 		}
732 	} while (wpid != pid && !requested_transition);
733 
734 	if (requested_transition) {
735 		(void)sigaction(SIGTSTP, &satstp, NULL);
736 		(void)sigaction(SIGHUP, &sahup, NULL);
737 		return (state_func_t)requested_transition;
738 	}
739 
740 	if (WIFSIGNALED(status)) {
741 		if (WTERMSIG(status) == SIGKILL) {
742 			/* executed /sbin/reboot; wait for the end quietly */
743 			sigset_t s;
744 
745 			(void)sigfillset(&s);
746 			for (;;)
747 				(void)sigsuspend(&s);
748 		} else {
749 			warning("single user shell terminated, restarting");
750 			(void)sigaction(SIGTSTP, &satstp, NULL);
751 			(void)sigaction(SIGHUP, &sahup, NULL);
752 			return (state_func_t) single_user;
753 		}
754 	}
755 
756 	runcom_mode = FASTBOOT;
757 	(void)sigaction(SIGTSTP, &satstp, NULL);
758 	(void)sigaction(SIGHUP, &sahup, NULL);
759 #ifndef LETS_GET_SMALL
760 	return (state_func_t) runcom;
761 #else /* LETS_GET_SMALL */
762 	return (state_func_t) single_user;
763 #endif /* LETS_GET_SMALL */
764 }
765 
766 #ifndef LETS_GET_SMALL
767 
768 /* ARGSUSED */
769 state_func_t
770 runetcrc(int trychroot)
771 {
772 	pid_t pid, wpid;
773 	int status;
774 	const char *argv[4];
775 	struct sigaction sa;
776 
777 	switch ((pid = fork())) {
778 	case 0:
779 		(void)sigemptyset(&sa.sa_mask);
780 		sa.sa_flags = 0;
781 		sa.sa_handler = SIG_IGN;
782 		(void)sigaction(SIGTSTP, &sa, NULL);
783 		(void)sigaction(SIGHUP, &sa, NULL);
784 
785 		setctty(_PATH_CONSOLE);
786 
787 		argv[0] = "sh";
788 		argv[1] = _PATH_RUNCOM;
789 		argv[2] = (runcom_mode == AUTOBOOT ? "autoboot" : 0);
790 		argv[3] = 0;
791 
792 		(void)sigprocmask(SIG_SETMASK, &sa.sa_mask, NULL);
793 
794 #ifdef CHROOT
795 		if (trychroot)
796 			if (chroot(rootdir) != 0) {
797 				warning("failed to chroot to %s, error: %m",
798 				    rootdir);
799 				_exit(1); 	/* force single user mode */
800 			}
801 #endif /* CHROOT */
802 
803 		(void)execv(INIT_BSHELL, __UNCONST(argv));
804 		stall("can't exec %s for %s: %m", INIT_BSHELL, _PATH_RUNCOM);
805 		_exit(1);	/* force single user mode */
806 		/*NOTREACHED*/
807 	case -1:
808 		emergency("can't fork for %s on %s: %m", INIT_BSHELL,
809 		    _PATH_RUNCOM);
810 		while (waitpid(-1, NULL, WNOHANG) > 0)
811 			continue;
812 		(void)sleep(STALL_TIMEOUT);
813 		return (state_func_t)single_user;
814 	default:
815 		break;
816 	}
817 
818 	/*
819 	 * Copied from single_user().  This is a bit paranoid.
820 	 */
821 	do {
822 		if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1)
823 			collect_child(wpid, status);
824 		if (wpid == -1) {
825 			if (errno == EINTR)
826 				continue;
827 			warning("wait for %s on %s failed: %m; going to "
828 			    "single user mode", INIT_BSHELL, _PATH_RUNCOM);
829 			return (state_func_t)single_user;
830 		}
831 		if (wpid == pid && WIFSTOPPED(status)) {
832 			warning("init: %s on %s stopped, restarting\n",
833 			    INIT_BSHELL, _PATH_RUNCOM);
834 			(void)kill(pid, SIGCONT);
835 			wpid = -1;
836 		}
837 	} while (wpid != pid);
838 
839 	if (WIFSIGNALED(status) && WTERMSIG(status) == SIGTERM &&
840 	    requested_transition == catatonia) {
841 		/* /etc/rc executed /sbin/reboot; wait for the end quietly */
842 		sigset_t s;
843 
844 		(void)sigfillset(&s);
845 		for (;;)
846 			(void)sigsuspend(&s);
847 	}
848 
849 	if (!WIFEXITED(status)) {
850 		warning("%s on %s terminated abnormally, going to "
851 		    "single user mode", INIT_BSHELL, _PATH_RUNCOM);
852 		return (state_func_t)single_user;
853 	}
854 
855 	if (WEXITSTATUS(status))
856 		return (state_func_t)single_user;
857 
858 	return (state_func_t) read_ttys;
859 }
860 
861 /*
862  * Run the system startup script.
863  */
864 state_func_t
865 runcom(void)
866 {
867 	state_func_t next_step;
868 
869 	/* Run /etc/rc and choose next state depending on the result. */
870 	next_step = runetcrc(0);
871 	if (next_step != (state_func_t) read_ttys)
872 		return (state_func_t) next_step;
873 
874 #ifdef CHROOT
875 	/*
876 	 * If init.root sysctl does not point to "/", we'll chroot and run
877 	 * The Real(tm) /etc/rc now.  Global variable rootdir will tell us
878 	 * where to go.
879 	 */
880 	if (shouldchroot()) {
881 		next_step = runetcrc(1);
882 		if (next_step != (state_func_t) read_ttys)
883 			return (state_func_t) next_step;
884 
885 		did_multiuser_chroot = 1;
886 	} else {
887 		did_multiuser_chroot = 0;
888 	}
889 #endif /* CHROOT */
890 
891 	/*
892 	 * Regardless of whether in chroot or not, we booted successfuly.
893 	 * It's time to spawn gettys (ie. next_step's value at this point).
894 	 */
895 	runcom_mode = AUTOBOOT;		/* the default */
896 	/* NB: should send a message to the session logger to avoid blocking. */
897 #ifdef SUPPORT_UTMPX
898 	logwtmpx("~", "reboot", "", 0, INIT_PROCESS);
899 #endif
900 #ifdef SUPPORT_UTMP
901 	logwtmp("~", "reboot", "");
902 #endif
903 	return (state_func_t) read_ttys;
904 }
905 
906 /*
907  * Open the session database.
908  *
909  * NB: We could pass in the size here; is it necessary?
910  */
911 int
912 start_session_db(void)
913 {
914 
915 	if (session_db && (*session_db->close)(session_db))
916 		emergency("session database close: %m");
917 	if ((session_db = dbopen(NULL, O_RDWR, 0, DB_HASH, NULL)) == 0) {
918 		emergency("session database open: %m");
919 		return (1);
920 	}
921 	return (0);
922 
923 }
924 
925 /*
926  * Add a new login session.
927  */
928 void
929 add_session(session_t *sp)
930 {
931 	DBT key;
932 	DBT data;
933 
934 	if (session_db == NULL)
935 		return;
936 
937 	key.data = &sp->se_process;
938 	key.size = sizeof sp->se_process;
939 	data.data = &sp;
940 	data.size = sizeof sp;
941 
942 	if ((*session_db->put)(session_db, &key, &data, 0))
943 		emergency("insert %d: %m", sp->se_process);
944 }
945 
946 /*
947  * Delete an old login session.
948  */
949 void
950 del_session(session_t *sp)
951 {
952 	DBT key;
953 
954 	key.data = &sp->se_process;
955 	key.size = sizeof sp->se_process;
956 
957 	if ((*session_db->del)(session_db, &key, 0))
958 		emergency("delete %d: %m", sp->se_process);
959 }
960 
961 /*
962  * Look up a login session by pid.
963  */
964 session_t *
965 find_session(pid_t pid)
966 {
967 	DBT key;
968 	DBT data;
969 	session_t *ret;
970 
971 	if (session_db == NULL)
972 		return NULL;
973 
974 	key.data = &pid;
975 	key.size = sizeof pid;
976 	if ((*session_db->get)(session_db, &key, &data, 0) != 0)
977 		return 0;
978 	(void)memmove(&ret, data.data, sizeof(ret));
979 	return ret;
980 }
981 
982 /*
983  * Construct an argument vector from a command line.
984  */
985 char **
986 construct_argv(char *command)
987 {
988 	int argc = 0;
989 	char **argv = malloc(((strlen(command) + 1) / 2 + 1) * sizeof (char *));
990 	static const char separators[] = " \t";
991 
992 	if (argv == NULL)
993 		return (NULL);
994 
995 	if ((argv[argc++] = strtok(command, separators)) == 0) {
996 		free(argv);
997 		return (NULL);
998 	}
999 	while ((argv[argc++] = strtok(NULL, separators)) != NULL)
1000 		continue;
1001 	return (argv);
1002 }
1003 
1004 /*
1005  * Deallocate a session descriptor.
1006  */
1007 void
1008 free_session(session_t *sp)
1009 {
1010 
1011 	free(sp->se_device);
1012 	if (sp->se_getty) {
1013 		free(sp->se_getty);
1014 		free(sp->se_getty_argv);
1015 	}
1016 	if (sp->se_window) {
1017 		free(sp->se_window);
1018 		free(sp->se_window_argv);
1019 	}
1020 	free(sp);
1021 }
1022 
1023 /*
1024  * Allocate a new session descriptor.
1025  */
1026 session_t *
1027 new_session(session_t *sprev, int session_index, struct ttyent *typ)
1028 {
1029 	session_t *sp;
1030 
1031 	if ((typ->ty_status & TTY_ON) == 0 || typ->ty_name == NULL ||
1032 	    typ->ty_getty == NULL)
1033 		return (NULL);
1034 
1035 	sp = malloc(sizeof (session_t));
1036 	if (sp == NULL)
1037 		return NULL;
1038 	memset(sp, 0, sizeof *sp);
1039 
1040 	sp->se_flags = SE_PRESENT;
1041 	sp->se_index = session_index;
1042 
1043 	(void)asprintf(&sp->se_device, "%s%s", _PATH_DEV, typ->ty_name);
1044 	if (!sp->se_device)
1045 		return NULL;
1046 
1047 	if (setupargv(sp, typ) == 0) {
1048 		free_session(sp);
1049 		return (NULL);
1050 	}
1051 
1052 	sp->se_next = NULL;
1053 	if (sprev == NULL) {
1054 		sessions = sp;
1055 		sp->se_prev = NULL;
1056 	} else {
1057 		sprev->se_next = sp;
1058 		sp->se_prev = sprev;
1059 	}
1060 
1061 	return (sp);
1062 }
1063 
1064 /*
1065  * Calculate getty and if useful window argv vectors.
1066  */
1067 int
1068 setupargv(session_t *sp, struct ttyent *typ)
1069 {
1070 
1071 	if (sp->se_getty) {
1072 		free(sp->se_getty);
1073 		free(sp->se_getty_argv);
1074 	}
1075 	(void)asprintf(&sp->se_getty, "%s %s", typ->ty_getty, typ->ty_name);
1076 	if (!sp->se_getty)
1077 		return (0);
1078 	sp->se_getty_argv = construct_argv(sp->se_getty);
1079 	if (sp->se_getty_argv == NULL) {
1080 		warning("can't parse getty for port %s", sp->se_device);
1081 		free(sp->se_getty);
1082 		sp->se_getty = NULL;
1083 		return (0);
1084 	}
1085 	if (typ->ty_window) {
1086 		if (sp->se_window)
1087 			free(sp->se_window);
1088 		sp->se_window = strdup(typ->ty_window);
1089 		sp->se_window_argv = construct_argv(sp->se_window);
1090 		if (sp->se_window_argv == NULL) {
1091 			warning("can't parse window for port %s",
1092 			    sp->se_device);
1093 			free(sp->se_window);
1094 			sp->se_window = NULL;
1095 			return (0);
1096 		}
1097 	}
1098 	return (1);
1099 }
1100 
1101 /*
1102  * Walk the list of ttys and create sessions for each active line.
1103  */
1104 state_func_t
1105 read_ttys(void)
1106 {
1107 	int session_index = 0;
1108 	session_t *sp, *snext;
1109 	struct ttyent *typ;
1110 
1111 	/*
1112 	 * Destroy any previous session state.
1113 	 * There shouldn't be any, but just in case...
1114 	 */
1115 	for (sp = sessions; sp; sp = snext) {
1116 #ifndef LETS_GET_SMALL
1117 		if (sp->se_process)
1118 			clear_session_logs(sp, 0);
1119 #endif
1120 		snext = sp->se_next;
1121 		free_session(sp);
1122 	}
1123 	sessions = NULL;
1124 
1125 	if (start_session_db()) {
1126 		warning("read_ttys: start_session_db failed, death\n");
1127 #ifdef CHROOT
1128 		/* If /etc/rc ran in chroot, we want to kill any survivors. */
1129 		if (did_multiuser_chroot)
1130 			return (state_func_t)death;
1131 		else
1132 #endif /* CHROOT */
1133 			return (state_func_t)single_user;
1134 	}
1135 
1136 	do_setttyent();
1137 
1138 	/*
1139 	 * Allocate a session entry for each active port.
1140 	 * Note that sp starts at 0.
1141 	 */
1142 	while ((typ = getttyent()) != NULL)
1143 		if ((snext = new_session(sp, ++session_index, typ)) != NULL)
1144 			sp = snext;
1145 	endttyent();
1146 
1147 	return (state_func_t)multi_user;
1148 }
1149 
1150 /*
1151  * Start a window system running.
1152  */
1153 void
1154 start_window_system(session_t *sp)
1155 {
1156 	pid_t pid;
1157 	sigset_t mask;
1158 
1159 	if ((pid = fork()) == -1) {
1160 		emergency("can't fork for window system on port %s: %m",
1161 		    sp->se_device);
1162 		/* hope that getty fails and we can try again */
1163 		return;
1164 	}
1165 
1166 	if (pid)
1167 		return;
1168 
1169 	sigemptyset(&mask);
1170 	sigprocmask(SIG_SETMASK, &mask, NULL);
1171 
1172 	if (setsid() < 0)
1173 		emergency("setsid failed (window) %m");
1174 
1175 	(void)execv(sp->se_window_argv[0], sp->se_window_argv);
1176 	stall("can't exec window system '%s' for port %s: %m",
1177 	    sp->se_window_argv[0], sp->se_device);
1178 	_exit(1);
1179 }
1180 
1181 /*
1182  * Start a login session running.
1183  */
1184 pid_t
1185 start_getty(session_t *sp)
1186 {
1187 	pid_t pid;
1188 	sigset_t mask;
1189 	time_t current_time = time(NULL);
1190 
1191 	/*
1192 	 * fork(), not vfork() -- we can't afford to block.
1193 	 */
1194 	if ((pid = fork()) == -1) {
1195 		emergency("can't fork for getty on port %s: %m", sp->se_device);
1196 		return -1;
1197 	}
1198 
1199 	if (pid)
1200 		return pid;
1201 
1202 #ifdef CHROOT
1203 	/* If /etc/rc did proceed inside chroot, we have to try as well. */
1204 	if (did_multiuser_chroot)
1205 		if (chroot(rootdir) != 0) {
1206 			stall("can't chroot getty '%s' inside %s: %m",
1207 			    sp->se_getty_argv[0], rootdir);
1208 			_exit(1);
1209 		}
1210 #endif /* CHROOT */
1211 
1212 	if (current_time > sp->se_started &&
1213 	    current_time - sp->se_started < GETTY_SPACING) {
1214 		warning("getty repeating too quickly on port %s, sleeping",
1215 		    sp->se_device);
1216 		(void)sleep(GETTY_SLEEP);
1217 	}
1218 
1219 	if (sp->se_window) {
1220 		start_window_system(sp);
1221 		(void)sleep(WINDOW_WAIT);
1222 	}
1223 
1224 	(void)sigemptyset(&mask);
1225 	(void)sigprocmask(SIG_SETMASK, &mask, (sigset_t *) 0);
1226 
1227 	(void)execv(sp->se_getty_argv[0], sp->se_getty_argv);
1228 	stall("can't exec getty '%s' for port %s: %m",
1229 	    sp->se_getty_argv[0], sp->se_device);
1230 	_exit(1);
1231 	/*NOTREACHED*/
1232 }
1233 #endif /* LETS_GET_SMALL */
1234 
1235 /*
1236  * Collect exit status for a child.
1237  * If an exiting login, start a new login running.
1238  */
1239 void
1240 collect_child(pid_t pid, int status)
1241 {
1242 #ifndef LETS_GET_SMALL
1243 	session_t *sp, *sprev, *snext;
1244 
1245 	if (! sessions)
1246 		return;
1247 
1248 	if ((sp = find_session(pid)) == NULL)
1249 		return;
1250 
1251 	clear_session_logs(sp, status);
1252 	del_session(sp);
1253 	sp->se_process = 0;
1254 
1255 	if (sp->se_flags & SE_SHUTDOWN) {
1256 		if ((sprev = sp->se_prev) != NULL)
1257 			sprev->se_next = sp->se_next;
1258 		else
1259 			sessions = sp->se_next;
1260 		if ((snext = sp->se_next) != NULL)
1261 			snext->se_prev = sp->se_prev;
1262 		free_session(sp);
1263 		return;
1264 	}
1265 
1266 	if ((pid = start_getty(sp)) == -1) {
1267 		/* serious trouble */
1268 		requested_transition = clean_ttys;
1269 		return;
1270 	}
1271 
1272 	sp->se_process = pid;
1273 	sp->se_started = time(NULL);
1274 	add_session(sp);
1275 #endif /* LETS_GET_SMALL */
1276 }
1277 
1278 /*
1279  * Catch a signal and request a state transition.
1280  */
1281 void
1282 transition_handler(int sig)
1283 {
1284 
1285 	switch (sig) {
1286 #ifndef LETS_GET_SMALL
1287 	case SIGHUP:
1288 		requested_transition = clean_ttys;
1289 		break;
1290 	case SIGTERM:
1291 		requested_transition = death;
1292 		break;
1293 	case SIGTSTP:
1294 		requested_transition = catatonia;
1295 		break;
1296 #endif /* LETS_GET_SMALL */
1297 	default:
1298 		requested_transition = 0;
1299 		break;
1300 	}
1301 }
1302 
1303 #ifndef LETS_GET_SMALL
1304 /*
1305  * Take the system multiuser.
1306  */
1307 state_func_t
1308 multi_user(void)
1309 {
1310 	pid_t pid;
1311 	int status;
1312 	session_t *sp;
1313 
1314 	requested_transition = 0;
1315 
1316 	/*
1317 	 * If the administrator has not set the security level to -1
1318 	 * to indicate that the kernel should not run multiuser in secure
1319 	 * mode, and the run script has not set a higher level of security
1320 	 * than level 1, then put the kernel into secure mode.
1321 	 */
1322 	if (getsecuritylevel() == 0)
1323 		setsecuritylevel(1);
1324 
1325 	for (sp = sessions; sp; sp = sp->se_next) {
1326 		if (sp->se_process)
1327 			continue;
1328 		if ((pid = start_getty(sp)) == -1) {
1329 			/* serious trouble */
1330 			requested_transition = clean_ttys;
1331 			break;
1332 		}
1333 		sp->se_process = pid;
1334 		sp->se_started = time(NULL);
1335 		add_session(sp);
1336 	}
1337 
1338 	while (!requested_transition)
1339 		if ((pid = waitpid(-1, &status, 0)) != -1)
1340 			collect_child(pid, status);
1341 
1342 	return (state_func_t)requested_transition;
1343 }
1344 
1345 /*
1346  * This is an n-squared algorithm.  We hope it isn't run often...
1347  */
1348 state_func_t
1349 clean_ttys(void)
1350 {
1351 	session_t *sp, *sprev;
1352 	struct ttyent *typ;
1353 	int session_index = 0;
1354 	int devlen;
1355 
1356 	for (sp = sessions; sp; sp = sp->se_next)
1357 		sp->se_flags &= ~SE_PRESENT;
1358 
1359 	do_setttyent();
1360 
1361 	devlen = sizeof(_PATH_DEV) - 1;
1362 	while ((typ = getttyent()) != NULL) {
1363 		++session_index;
1364 
1365 		for (sprev = 0, sp = sessions; sp; sprev = sp, sp = sp->se_next)
1366 			if (strcmp(typ->ty_name, sp->se_device + devlen) == 0)
1367 				break;
1368 
1369 		if (sp) {
1370 			sp->se_flags |= SE_PRESENT;
1371 			if (sp->se_index != session_index) {
1372 				warning("port %s changed utmp index from "
1373 				    "%d to %d", sp->se_device, sp->se_index,
1374 				    session_index);
1375 				sp->se_index = session_index;
1376 			}
1377 			if ((typ->ty_status & TTY_ON) == 0 ||
1378 			    typ->ty_getty == 0) {
1379 				sp->se_flags |= SE_SHUTDOWN;
1380 				if (sp->se_process != 0)
1381 					(void)kill(sp->se_process, SIGHUP);
1382 				continue;
1383 			}
1384 			sp->se_flags &= ~SE_SHUTDOWN;
1385 			if (setupargv(sp, typ) == 0) {
1386 				warning("can't parse getty for port %s",
1387 				    sp->se_device);
1388 				sp->se_flags |= SE_SHUTDOWN;
1389 				if (sp->se_process != 0)
1390 					(void)kill(sp->se_process, SIGHUP);
1391 			}
1392 			continue;
1393 		}
1394 
1395 		new_session(sprev, session_index, typ);
1396 	}
1397 
1398 	endttyent();
1399 
1400 	for (sp = sessions; sp; sp = sp->se_next)
1401 		if ((sp->se_flags & SE_PRESENT) == 0) {
1402 			sp->se_flags |= SE_SHUTDOWN;
1403 			if (sp->se_process != 0)
1404 				(void)kill(sp->se_process, SIGHUP);
1405 		}
1406 
1407 	return (state_func_t)multi_user;
1408 }
1409 
1410 /*
1411  * Block further logins.
1412  */
1413 state_func_t
1414 catatonia(void)
1415 {
1416 	session_t *sp;
1417 
1418 	for (sp = sessions; sp; sp = sp->se_next)
1419 		sp->se_flags |= SE_SHUTDOWN;
1420 
1421 	return (state_func_t)multi_user;
1422 }
1423 #endif /* LETS_GET_SMALL */
1424 
1425 /*
1426  * Note SIGALRM.
1427  */
1428 void
1429 /*ARGSUSED*/
1430 alrm_handler(int sig)
1431 {
1432 
1433 	clang = 1;
1434 }
1435 
1436 #ifndef LETS_GET_SMALL
1437 /*
1438  * Bring the system down to single user.
1439  */
1440 state_func_t
1441 death(void)
1442 {
1443 	session_t *sp;
1444 	int i, status;
1445 	pid_t pid;
1446 	static const int death_sigs[3] = { SIGHUP, SIGTERM, SIGKILL };
1447 
1448 	for (sp = sessions; sp; sp = sp->se_next)
1449 		sp->se_flags |= SE_SHUTDOWN;
1450 
1451 	/* NB: should send a message to the session logger to avoid blocking. */
1452 #ifdef SUPPORT_UTMPX
1453 	logwtmpx("~", "shutdown", "", 0, INIT_PROCESS);
1454 #endif
1455 #ifdef SUPPORT_UTMP
1456 	logwtmp("~", "shutdown", "");
1457 #endif
1458 
1459 	for (i = 0; i < 3; ++i) {
1460 		if (kill(-1, death_sigs[i]) == -1 && errno == ESRCH)
1461 			return (state_func_t)single_user;
1462 
1463 		clang = 0;
1464 		alarm(DEATH_WATCH);
1465 		do
1466 			if ((pid = waitpid(-1, &status, 0)) != -1)
1467 				collect_child(pid, status);
1468 		while (clang == 0 && errno != ECHILD);
1469 
1470 		if (errno == ECHILD)
1471 			return (state_func_t)single_user;
1472 	}
1473 
1474 	warning("some processes would not die; ps axl advised");
1475 
1476 	return (state_func_t)single_user;
1477 }
1478 #endif /* LETS_GET_SMALL */
1479 
1480 #ifdef MFS_DEV_IF_NO_CONSOLE
1481 
1482 static void
1483 mapfile(struct mappedfile *mf)
1484 {
1485 	int fd;
1486 	struct stat st;
1487 
1488 	if (lstat(mf->path, &st) == -1)
1489 		return;
1490 
1491 	if ((st.st_mode & S_IFMT) == S_IFLNK) {
1492 		mf->buf = malloc(st.st_size + 1);
1493 		if (mf->buf == NULL)
1494 			return;
1495 		mf->buf[st.st_size] = 0;
1496 		if (readlink(mf->path, mf->buf, st.st_size) != st.st_size)
1497 			return;
1498 		mf->len = -1;
1499 		return;
1500 	}
1501 
1502 	if ((fd = open(mf->path, O_RDONLY)) == -1)
1503 		return;
1504 	mf->buf = mmap(0, (size_t)st.st_size, PROT_READ,
1505 			MAP_FILE|MAP_SHARED, fd, (off_t)0);
1506 	(void)close(fd);
1507 	if (mf->buf == MAP_FAILED)
1508 		return;
1509 	mf->len = st.st_size;
1510 }
1511 
1512 static void
1513 writefile(struct mappedfile *mf)
1514 {
1515 	int fd;
1516 
1517 	if (mf->len == -1) {
1518 		symlink(mf->buf, mf->path);
1519 		free(mf->buf);
1520 		return;
1521 	}
1522 
1523 	if (mf->len == 0)
1524 		return;
1525 	fd = open(mf->path, O_WRONLY | O_CREAT | O_TRUNC, 0755);
1526 	if (fd == -1)
1527 		return;
1528 	(void)write(fd, mf->buf, mf->len);
1529 	(void)munmap(mf->buf, mf->len);
1530 	(void)close(fd);
1531 }
1532 
1533 static int
1534 mfs_dev(void)
1535 {
1536 	/*
1537 	 * We cannot print errors so we bail out silently...
1538 	 */
1539 	pid_t pid;
1540 	int status;
1541 	dev_t dev;
1542 	char *fs_size;
1543 #ifdef CPU_CONSDEV
1544 	static int name[2] = { CTL_MACHDEP, CPU_CONSDEV };
1545 	size_t olen;
1546 #endif
1547 
1548 	/* If we have /dev/console, assume all is OK  */
1549 	if (access(_PATH_CONSOLE, F_OK) != -1)
1550 		return(0);
1551 
1552 	/* Grab the contents of MAKEDEV */
1553 	mapfile(&mfile[0]);
1554 
1555 	/* Grab the contents of MAKEDEV.local */
1556 	mapfile(&mfile[1]);
1557 
1558 	/* Mount an mfs over /dev so we can create devices */
1559 	switch ((pid = fork())) {
1560 	case 0:
1561 		asprintf(&fs_size, "%d", FSSIZE);
1562 		if (fs_size == NULL)
1563 			return(-1);
1564 		(void)execl(INIT_MOUNT_MFS, "mount_mfs",
1565 		    "-b", "4096", "-f", "512",
1566 		    "-s", fs_size, "-n", STR(NINODE),
1567 		    "-p", "0755",
1568 		    "swap", "/dev", NULL);
1569 		_exit(1);
1570 		/*NOTREACHED*/
1571 
1572 	case -1:
1573 		return(-1);
1574 
1575 	default:
1576 		if (waitpid(pid, &status, 0) == -1)
1577 			return(-1);
1578 		if (status != 0)
1579 			return(-1);
1580 		break;
1581 	}
1582 
1583 #ifdef CPU_CONSDEV
1584 	olen = sizeof(dev);
1585 	if (sysctl(name, sizeof(name) / sizeof(name[0]), &dev, &olen,
1586 	    NULL, 0) == -1)
1587 #endif
1588 		dev = makedev(0, 0);
1589 
1590 	/* Make a console for us, so we can see things happening */
1591 	if (mknod(_PATH_CONSOLE, 0666 | S_IFCHR, dev) == -1)
1592 		return(-1);
1593 
1594 	(void)freopen(_PATH_CONSOLE, "a", stderr);
1595 
1596 	warnx("Creating mfs /dev (%d blocks, %d inodes)", FSSIZE, NINODE);
1597 
1598 	/* Create a MAKEDEV script in the mfs /dev */
1599 	writefile(&mfile[0]);
1600 
1601 	/* Create a MAKEDEV.local script in the mfs /dev */
1602 	writefile(&mfile[1]);
1603 
1604 	/* Run the makedev script to create devices */
1605 	switch ((pid = fork())) {
1606 	case 0:
1607 		dup2(2, 1);	/* Give the script stdout */
1608 		if (chdir("/dev") == 0)
1609 			(void)execl(INIT_BSHELL, "sh",
1610 			    mfile[0].len ? "./MAKEDEV" : "/etc/MAKEDEV",
1611 			    "init", NULL);
1612 		_exit(1);
1613 		/* NOTREACHED */
1614 
1615 	case -1:
1616 		break;
1617 
1618 	default:
1619 		if (waitpid(pid, &status, 0) == -1)
1620 			break;
1621 		if (status != 0) {
1622 			errno = EINVAL;
1623 			break;
1624 		}
1625 		return 0;
1626 	}
1627 	warn("Unable to run MAKEDEV");
1628 	return (-1);
1629 }
1630 #endif
1631 
1632 int
1633 do_setttyent(void)
1634 {
1635 	endttyent();
1636 #ifdef CHROOT
1637 	if (did_multiuser_chroot) {
1638 		char path[PATH_MAX];
1639 
1640 		snprintf(path, sizeof(path), "%s/%s", rootdir, _PATH_TTYS);
1641 
1642 		return setttyentpath(path);
1643 	} else
1644 #endif /* CHROOT */
1645 		return setttyent();
1646 }
1647 
1648 #if !defined(LETS_GET_SMALL) && defined(CHROOT)
1649 
1650 int
1651 createsysctlnode()
1652 {
1653 	struct sysctlnode node;
1654 	int mib[2];
1655 	size_t len;
1656 
1657 	/*
1658 	 * Create top-level dynamic sysctl node.  Its child nodes will only
1659 	 * be readable by the superuser, since regular mortals should not
1660 	 * care ("Sssh, it's a secret!").  Additionally, both nodes become
1661 	 * read-only at securelevel 1.
1662 	 */
1663 	len = sizeof(struct sysctlnode);
1664 	mib[0] = CTL_CREATE;
1665 
1666 	memset(&node, 0, len);
1667 	node.sysctl_flags = SYSCTL_VERSION | CTLFLAG_READWRITE |
1668 	    CTLFLAG_PRIVATE | CTLFLAG_READONLY1 | CTLTYPE_NODE;
1669 	node.sysctl_num = CTL_CREATE;
1670 	snprintf(node.sysctl_name, SYSCTL_NAMELEN, "init");
1671 	if (sysctl(&mib[0], 1, &node, &len, &node, len) == -1) {
1672 		warning("could not create init node, error = %d", errno);
1673 		return (-1);
1674 	}
1675 
1676 	/*
1677 	 * Create second level dynamic node capable of holding pathname.
1678 	 * Provide "/" as the default value.
1679 	 */
1680 	len = sizeof(struct sysctlnode);
1681 	mib[0] = node.sysctl_num;
1682 	mib[1] = CTL_CREATE;
1683 
1684 	memset(&node, 0, len);
1685 	node.sysctl_flags = SYSCTL_VERSION | CTLFLAG_READWRITE |
1686 	    CTLFLAG_READONLY1 | CTLTYPE_STRING | CTLFLAG_OWNDATA;
1687 	node.sysctl_size = _POSIX_PATH_MAX;
1688 	node.sysctl_data = __UNCONST("/");
1689 	node.sysctl_num = CTL_CREATE;
1690 	snprintf(node.sysctl_name, SYSCTL_NAMELEN, "root");
1691 	if (sysctl(&mib[0], 2, NULL, NULL, &node, len) == -1) {
1692 		warning("could not create init.root node, error = %d", errno);
1693 		return (-1);
1694 	}
1695 
1696 	return (0);
1697 }
1698 
1699 int
1700 shouldchroot()
1701 {
1702 	struct sysctlnode node;
1703 	size_t len, cnt;
1704 	int mib;
1705 
1706 	len = sizeof(struct sysctlnode);
1707 
1708 	if (sysctlbyname("init.root", rootdir, &len, NULL, 0) == -1) {
1709 		warning("could not read init.root, error = %d", errno);
1710 
1711 		/* Child killed our node. Recreate it. */
1712 		if (errno == ENOENT) {
1713 			/* Destroy whatever is left, recreate from scratch. */
1714 			if (sysctlnametomib("init", &mib, &cnt) != -1) {
1715 				memset(&node, 0, sizeof(node));
1716 				node.sysctl_flags = SYSCTL_VERSION;
1717 				node.sysctl_num = mib;
1718 				mib = CTL_DESTROY;
1719 
1720 				(void)sysctl(&mib, 1, NULL, NULL, &node,
1721 				    sizeof(node));
1722 			}
1723 
1724 			createsysctlnode();
1725 		}
1726 
1727 		/* We certainly won't chroot. */
1728 		return (0);
1729 	}
1730 
1731 	if (rootdir[len] != '\0' || strlen(rootdir) != len - 1) {
1732 		warning("init.root is not a string");
1733 		return (0);
1734 	}
1735 
1736 	if (strcmp(rootdir, "/") == 0)
1737 		return (0);
1738 
1739 	return (1);
1740 }
1741 
1742 #endif /* !LETS_GET_SMALL && CHROOT */
1743