init.c revision 1.43 
1/*	$OpenBSD: init.c,v 1.43 2010/09/29 13:23:37 dcoppa Exp $	*/
2/*	$NetBSD: init.c,v 1.22 1996/05/15 23:29:33 jtc Exp $	*/
3
4/*-
5 * Copyright (c) 1991, 1993
6 *	The Regents of the University of California.  All rights reserved.
7 *
8 * This code is derived from software contributed to Berkeley by
9 * Donn Seeley at Berkeley Software Design, Inc.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 *    notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 *    notice, this list of conditions and the following disclaimer in the
18 *    documentation and/or other materials provided with the distribution.
19 * 3. Neither the name of the University nor the names of its contributors
20 *    may be used to endorse or promote products derived from this software
21 *    without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36#include <sys/param.h>
37#include <sys/sysctl.h>
38#include <sys/wait.h>
39#include <sys/reboot.h>
40
41#include <db.h>
42#include <err.h>
43#include <errno.h>
44#include <fcntl.h>
45#include <signal.h>
46#include <stdarg.h>
47#include <stdio.h>
48#include <stdlib.h>
49#include <string.h>
50#include <syslog.h>
51#include <time.h>
52#include <ttyent.h>
53#include <unistd.h>
54#include <util.h>
55
56#ifdef SECURE
57#include <pwd.h>
58#endif
59
60#ifdef LOGIN_CAP
61#include <login_cap.h>
62#endif
63
64#include "pathnames.h"
65
66/*
67 * Sleep times; used to prevent thrashing.
68 */
69#define	GETTY_SPACING		 5	/* N secs minimum getty spacing */
70#define	GETTY_SLEEP		30	/* sleep N secs after spacing problem */
71#define	WINDOW_WAIT		 3	/* wait N secs after starting window */
72#define	STALL_TIMEOUT		30	/* wait N secs after warning */
73#define	DEATH_WATCH		10	/* wait N secs for procs to die */
74
75/*
76 * User-based resource limits.
77 */
78#define RESOURCE_RC		"daemon"
79#define RESOURCE_WINDOW		"default"
80#define RESOURCE_GETTY		"default"
81
82#ifndef DEFAULT_STATE
83#define DEFAULT_STATE		runcom
84#endif
85
86void handle(sig_t, ...);
87void delset(sigset_t *, ...);
88
89void stall(char *, ...);
90void warning(char *, ...);
91void emergency(char *, ...);
92void disaster(int);
93void badsys(int);
94
95/*
96 * We really need a recursive typedef...
97 * The following at least guarantees that the return type of (*state_t)()
98 * is sufficiently wide to hold a function pointer.
99 */
100typedef long (*state_func_t)(void);
101typedef state_func_t (*state_t)(void);
102
103state_func_t single_user(void);
104state_func_t runcom(void);
105state_func_t read_ttys(void);
106state_func_t multi_user(void);
107state_func_t clean_ttys(void);
108state_func_t catatonia(void);
109state_func_t death(void);
110state_func_t hard_death(void);
111state_func_t nice_death(void);
112
113enum { AUTOBOOT, FASTBOOT } runcom_mode = AUTOBOOT;
114
115void transition(state_t);
116state_t requested_transition = DEFAULT_STATE;
117
118void setctty(char *);
119
120typedef struct init_session {
121	int	se_index;		/* index of entry in ttys file */
122	pid_t	se_process;		/* controlling process */
123	time_t	se_started;		/* used to avoid thrashing */
124	int	se_flags;		/* status of session */
125#define	SE_SHUTDOWN	0x1		/* session won't be restarted */
126#define	SE_PRESENT	0x2		/* session is in /etc/ttys */
127#define	SE_DEVEXISTS	0x4		/* open does not result in ENODEV */
128	char	*se_device;		/* filename of port */
129	char	*se_getty;		/* what to run on that port */
130	char	**se_getty_argv;	/* pre-parsed argument array */
131	char	*se_window;		/* window system (started only once) */
132	char	**se_window_argv;	/* pre-parsed argument array */
133	struct	init_session *se_prev;
134	struct	init_session *se_next;
135} session_t;
136
137void free_session(session_t *);
138session_t *new_session(session_t *, int, struct ttyent *);
139session_t *sessions;
140
141char **construct_argv(char *);
142void start_window_system(session_t *);
143void collect_child(pid_t);
144pid_t start_getty(session_t *);
145void transition_handler(int);
146void alrm_handler(int);
147void setsecuritylevel(int);
148int getsecuritylevel(void);
149int setupargv(session_t *, struct ttyent *);
150int clang;
151
152#ifdef LOGIN_CAP
153void setprocresources(char *);
154#else
155#define setprocresources(p)
156#endif
157
158void clear_session_logs(session_t *);
159
160int start_session_db(void);
161void add_session(session_t *);
162void del_session(session_t *);
163session_t *find_session(pid_t);
164DB *session_db;
165
166/*
167 * The mother of all processes.
168 */
169int
170main(int argc, char *argv[])
171{
172	int c;
173	struct sigaction sa;
174	sigset_t mask;
175
176	/* Dispose of random users. */
177	if (getuid() != 0) {
178		(void)fprintf(stderr, "init: %s\n", strerror(EPERM));
179		exit (1);
180	}
181
182	/* System V users like to reexec init. */
183	if (getpid() != 1) {
184		(void)fprintf(stderr, "init: already running\n");
185		exit (1);
186	}
187
188	/*
189	 * Note that this does NOT open a file...
190	 * Does 'init' deserve its own facility number?
191	 */
192	openlog("init", LOG_CONS|LOG_ODELAY, LOG_AUTH);
193
194	/*
195	 * Create an initial session.
196	 */
197	if (setsid() < 0)
198		warning("initial setsid() failed: %m");
199
200	/*
201	 * Establish an initial user so that programs running
202	 * single user do not freak out and die (like passwd).
203	 */
204	if (setlogin("root") < 0)
205		warning("setlogin() failed: %m");
206
207	/*
208	 * This code assumes that we always get arguments through flags,
209	 * never through bits set in some random machine register.
210	 */
211	while ((c = getopt(argc, argv, "sf")) != -1)
212		switch (c) {
213		case 's':
214			requested_transition = single_user;
215			break;
216		case 'f':
217			runcom_mode = FASTBOOT;
218			break;
219		default:
220			warning("unrecognized flag '-%c'", c);
221			break;
222		}
223
224	if (optind != argc)
225		warning("ignoring excess arguments");
226
227	/*
228	 * We catch or block signals rather than ignore them,
229	 * so that they get reset on exec.
230	 */
231	handle(badsys, SIGSYS, 0);
232	handle(disaster, SIGABRT, SIGFPE, SIGILL, SIGSEGV,
233	    SIGBUS, SIGXCPU, SIGXFSZ, 0);
234	handle(transition_handler, SIGHUP, SIGTERM, SIGTSTP, SIGUSR1,
235	    SIGUSR2, 0);
236	handle(alrm_handler, SIGALRM, 0);
237	sigfillset(&mask);
238	delset(&mask, SIGABRT, SIGFPE, SIGILL, SIGSEGV, SIGBUS, SIGSYS,
239	    SIGXCPU, SIGXFSZ, SIGHUP, SIGTERM, SIGUSR1, SIGUSR2,
240	    SIGTSTP, SIGALRM, 0);
241	sigprocmask(SIG_SETMASK, &mask, NULL);
242	memset(&sa, 0, sizeof sa);
243	sigemptyset(&sa.sa_mask);
244	sa.sa_flags = 0;
245	sa.sa_handler = SIG_IGN;
246	(void) sigaction(SIGTTIN, &sa, NULL);
247	(void) sigaction(SIGTTOU, &sa, NULL);
248
249	/*
250	 * Paranoia.
251	 */
252	close(STDIN_FILENO);
253	close(STDOUT_FILENO);
254	close(STDERR_FILENO);
255
256	/*
257	 * Start the state machine.
258	 */
259	transition(requested_transition);
260
261	/*
262	 * Should never reach here.
263	 */
264	exit(1);
265}
266
267/*
268 * Associate a function with a signal handler.
269 */
270void
271handle(sig_t handler, ...)
272{
273	int sig;
274	struct sigaction sa;
275	sigset_t mask_everything;
276	va_list ap;
277
278	va_start(ap, handler);
279
280	memset(&sa, 0, sizeof sa);
281	sa.sa_handler = handler;
282	sigfillset(&mask_everything);
283
284	while ((sig = va_arg(ap, int))) {
285		sa.sa_mask = mask_everything;
286		/* XXX SA_RESTART? */
287		sa.sa_flags = sig == SIGCHLD ? SA_NOCLDSTOP : 0;
288		sigaction(sig, &sa, NULL);
289	}
290	va_end(ap);
291}
292
293/*
294 * Delete a set of signals from a mask.
295 */
296void
297delset(sigset_t *maskp, ...)
298{
299	int sig;
300	va_list ap;
301
302	va_start(ap, maskp);
303	while ((sig = va_arg(ap, int)))
304		sigdelset(maskp, sig);
305	va_end(ap);
306}
307
308/*
309 * Log a message and sleep for a while (to give someone an opportunity
310 * to read it and to save log or hardcopy output if the problem is chronic).
311 * NB: should send a message to the session logger to avoid blocking.
312 */
313void
314stall(char *message, ...)
315{
316	va_list ap;
317
318	va_start(ap, message);
319	vsyslog(LOG_ALERT, message, ap);
320	va_end(ap);
321	closelog();
322	sleep(STALL_TIMEOUT);
323}
324
325/*
326 * Like stall(), but doesn't sleep.
327 * If cpp had variadic macros, the two functions could be #defines for another.
328 * NB: should send a message to the session logger to avoid blocking.
329 */
330void
331warning(char *message, ...)
332{
333	va_list ap;
334
335	va_start(ap, message);
336	vsyslog(LOG_ALERT, message, ap);
337	va_end(ap);
338	closelog();
339}
340
341/*
342 * Log an emergency message.
343 * NB: should send a message to the session logger to avoid blocking.
344 */
345void
346emergency(char *message, ...)
347{
348	struct syslog_data sdata = SYSLOG_DATA_INIT;
349	va_list ap;
350
351	va_start(ap, message);
352	vsyslog_r(LOG_EMERG, &sdata, message, ap);
353	va_end(ap);
354}
355
356/*
357 * Catch a SIGSYS signal.
358 *
359 * These may arise if a system does not support sysctl.
360 * We tolerate up to 25 of these, then throw in the towel.
361 */
362void
363badsys(int sig)
364{
365	static int badcount = 0;
366
367	if (badcount++ < 25)
368		return;
369	disaster(sig);
370}
371
372/*
373 * Catch an unexpected signal.
374 */
375void
376disaster(int sig)
377{
378	emergency("fatal signal: %s", strsignal(sig));
379
380	sleep(STALL_TIMEOUT);
381	_exit(sig);		/* reboot */
382}
383
384/*
385 * Get the security level of the kernel.
386 */
387int
388getsecuritylevel(void)
389{
390#ifdef KERN_SECURELVL
391	int name[2], curlevel;
392	size_t len;
393
394	name[0] = CTL_KERN;
395	name[1] = KERN_SECURELVL;
396	len = sizeof curlevel;
397	if (sysctl(name, 2, &curlevel, &len, NULL, 0) == -1) {
398		emergency("cannot get kernel security level: %s",
399		    strerror(errno));
400		return (-1);
401	}
402	return (curlevel);
403#else
404	return (-1);
405#endif
406}
407
408/*
409 * Set the security level of the kernel.
410 */
411void
412setsecuritylevel(int newlevel)
413{
414#ifdef KERN_SECURELVL
415	int name[2], curlevel;
416
417	curlevel = getsecuritylevel();
418	if (newlevel == curlevel)
419		return;
420	name[0] = CTL_KERN;
421	name[1] = KERN_SECURELVL;
422	if (sysctl(name, 2, NULL, NULL, &newlevel, sizeof newlevel) == -1) {
423		emergency(
424		    "cannot change kernel security level from %d to %d: %s",
425		    curlevel, newlevel, strerror(errno));
426		return;
427	}
428#ifdef SECURE
429	warning("kernel security level changed from %d to %d",
430	    curlevel, newlevel);
431#endif
432#endif
433}
434
435/*
436 * Change states in the finite state machine.
437 * The initial state is passed as an argument.
438 */
439void
440transition(state_t s)
441{
442	for (;;)
443		s = (state_t) (*s)();
444}
445
446/*
447 * Close out the accounting files for a login session.
448 * NB: should send a message to the session logger to avoid blocking.
449 */
450void
451clear_session_logs(session_t *sp)
452{
453	char *line = sp->se_device + sizeof(_PATH_DEV) - 1;
454
455	if (logout(line))
456		logwtmp(line, "", "");
457}
458
459/*
460 * Start a session and allocate a controlling terminal.
461 * Only called by children of init after forking.
462 */
463void
464setctty(char *name)
465{
466	int fd;
467
468	(void) revoke(name);
469	sleep(2);			/* leave DTR low */
470	if ((fd = open(name, O_RDWR)) == -1) {
471		stall("can't open %s: %m", name);
472		_exit(1);
473	}
474	if (login_tty(fd) == -1) {
475		stall("can't get %s for controlling terminal: %m", name);
476		_exit(1);
477	}
478}
479
480/*
481 * Bring the system up single user.
482 */
483state_func_t
484single_user(void)
485{
486	pid_t pid, wpid;
487	int status;
488	sigset_t mask;
489	char shell[MAXPATHLEN];		/* Allocate space here */
490	char name[MAXPATHLEN];		/* Name (argv[0]) of shell */
491	char *argv[2];
492#ifdef SECURE
493	struct ttyent *typ;
494	struct passwd *pp;
495	static const char banner[] =
496		"Enter root password, or ^D to go multi-user\n";
497	char *clear, *password;
498#endif
499
500	/* Init shell and name */
501	strlcpy(shell, _PATH_BSHELL, sizeof shell);
502	strlcpy(name, "-sh", sizeof name);
503
504	/*
505	 * If the kernel is in secure mode, downgrade it to insecure mode.
506	 */
507	if (getsecuritylevel() > 0)
508		setsecuritylevel(0);
509
510	if ((pid = fork()) == 0) {
511		/*
512		 * Start the single user session.
513		 */
514		setctty(_PATH_CONSOLE);
515
516#ifdef SECURE
517		/*
518		 * Check the root password.
519		 * We don't care if the console is 'on' by default;
520		 * it's the only tty that can be 'off' and 'secure'.
521		 */
522		typ = getttynam("console");
523		pp = getpwnam("root");
524		if (typ && (typ->ty_status & TTY_SECURE) == 0 && pp &&
525		    *pp->pw_passwd) {
526			write(STDERR_FILENO, banner, sizeof banner - 1);
527			for (;;) {
528				clear = getpass("Password:");
529				if (clear == 0 || *clear == '\0')
530					_exit(0);
531				password = crypt(clear, pp->pw_passwd);
532				memset(clear, 0, _PASSWORD_LEN);
533				if (strcmp(password, pp->pw_passwd) == 0)
534					break;
535				warning("single-user login failed\n");
536			}
537		}
538		endttyent();
539		endpwent();
540#endif /* SECURE */
541
542#ifdef DEBUGSHELL
543		{
544			char altshell[128], *cp = altshell;
545			int num;
546
547#define	SHREQUEST \
548	"Enter pathname of shell or RETURN for sh: "
549
550			(void)write(STDERR_FILENO,
551			    SHREQUEST, sizeof(SHREQUEST) - 1);
552			while ((num = read(STDIN_FILENO, cp, 1)) != -1 &&
553			    num != 0 && *cp != '\n' && cp < &altshell[127])
554				cp++;
555			*cp = '\0';
556
557			/* Copy in alternate shell */
558			if (altshell[0] != '\0'){
559				char *p;
560
561				/* Binary to exec */
562				strlcpy(shell, altshell, sizeof shell);
563
564				/* argv[0] */
565				p = strrchr(altshell, '/');
566				if(p == NULL) p = altshell;
567				else p++;
568
569				name[0] = '-';
570				strlcpy(&name[1], p, sizeof name -1);
571			}
572		}
573#endif /* DEBUGSHELL */
574
575		/*
576		 * Unblock signals.
577		 * We catch all the interesting ones,
578		 * and those are reset to SIG_DFL on exec.
579		 */
580		sigemptyset(&mask);
581		sigprocmask(SIG_SETMASK, &mask, NULL);
582
583		/*
584		 * Fire off a shell.
585		 * If the default one doesn't work, try the Bourne shell.
586		 */
587		argv[0] = name;
588		argv[1] = NULL;
589		setenv("PATH", _PATH_STDPATH, 1);
590		execv(shell, argv);
591		emergency("can't exec %s for single user: %m", shell);
592
593		argv[0] = "-sh";
594		argv[1] = NULL;
595		execv(_PATH_BSHELL, argv);
596		emergency("can't exec %s for single user: %m", _PATH_BSHELL);
597		sleep(STALL_TIMEOUT);
598		_exit(1);
599	}
600
601	if (pid == -1) {
602		/*
603		 * We are seriously hosed.  Do our best.
604		 */
605		emergency("can't fork single-user shell, trying again");
606		while (waitpid(-1, NULL, WNOHANG) > 0)
607			continue;
608		return (state_func_t) single_user;
609	}
610
611	requested_transition = 0;
612	do {
613		if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1)
614			collect_child(wpid);
615		if (wpid == -1) {
616			if (errno == EINTR)
617				continue;
618			warning("wait for single-user shell failed: %m; restarting");
619			return (state_func_t) single_user;
620		}
621		if (wpid == pid && WIFSTOPPED(status)) {
622			warning("init: shell stopped, restarting\n");
623			kill(pid, SIGCONT);
624			wpid = -1;
625		}
626	} while (wpid != pid && !requested_transition);
627
628	if (requested_transition)
629		return (state_func_t) requested_transition;
630
631	if (!WIFEXITED(status)) {
632		if (WTERMSIG(status) == SIGKILL) {
633			/*
634			 *  reboot(8) killed shell?
635			 */
636			warning("single user shell terminated.");
637			sleep(STALL_TIMEOUT);
638			_exit(0);
639		} else {
640			warning("single user shell terminated, restarting");
641			return (state_func_t) single_user;
642		}
643	}
644
645	runcom_mode = FASTBOOT;
646	return (state_func_t) runcom;
647}
648
649/*
650 * Run the system startup script.
651 */
652state_func_t
653runcom(void)
654{
655	pid_t pid, wpid;
656	int status;
657	char *argv[4];
658	struct sigaction sa;
659
660	if ((pid = fork()) == 0) {
661		memset(&sa, 0, sizeof sa);
662		sigemptyset(&sa.sa_mask);
663		sa.sa_flags = 0;
664		sa.sa_handler = SIG_IGN;
665		(void) sigaction(SIGTSTP, &sa, NULL);
666		(void) sigaction(SIGHUP, &sa, NULL);
667
668		setctty(_PATH_CONSOLE);
669
670		argv[0] = "sh";
671		argv[1] = _PATH_RUNCOM;
672		argv[2] = runcom_mode == AUTOBOOT ? "autoboot" : 0;
673		argv[3] = 0;
674
675		sigprocmask(SIG_SETMASK, &sa.sa_mask, NULL);
676
677		setprocresources(RESOURCE_RC);
678
679		execv(_PATH_BSHELL, argv);
680		stall("can't exec %s for %s: %m", _PATH_BSHELL, _PATH_RUNCOM);
681		_exit(1);	/* force single user mode */
682	}
683
684	if (pid == -1) {
685		emergency("can't fork for %s on %s: %m",
686			_PATH_BSHELL, _PATH_RUNCOM);
687		while (waitpid(-1, NULL, WNOHANG) > 0)
688			continue;
689		sleep(STALL_TIMEOUT);
690		return (state_func_t) single_user;
691	}
692
693	/*
694	 * Copied from single_user().  This is a bit paranoid.
695	 */
696	do {
697		if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1)
698			collect_child(wpid);
699		if (wpid == -1) {
700			if (errno == EINTR)
701				continue;
702			warning("wait for %s on %s failed: %m; going to single user mode",
703			    _PATH_BSHELL, _PATH_RUNCOM);
704			return (state_func_t) single_user;
705		}
706		if (wpid == pid && WIFSTOPPED(status)) {
707			warning("init: %s on %s stopped, restarting\n",
708			    _PATH_BSHELL, _PATH_RUNCOM);
709			kill(pid, SIGCONT);
710			wpid = -1;
711		}
712	} while (wpid != pid);
713
714	if (WIFSIGNALED(status) && WTERMSIG(status) == SIGTERM &&
715	    requested_transition == catatonia) {
716		/* /etc/rc executed /sbin/reboot; wait for the end quietly */
717		sigset_t s;
718
719		sigfillset(&s);
720		for (;;)
721			sigsuspend(&s);
722	}
723
724	if (!WIFEXITED(status)) {
725		warning("%s on %s terminated abnormally, going to single user mode",
726		    _PATH_BSHELL, _PATH_RUNCOM);
727		return (state_func_t) single_user;
728	}
729
730	if (WEXITSTATUS(status))
731		return (state_func_t) single_user;
732
733	runcom_mode = AUTOBOOT;		/* the default */
734	/* NB: should send a message to the session logger to avoid blocking. */
735	logwtmp("~", "reboot", "");
736	return (state_func_t) read_ttys;
737}
738
739/*
740 * Open the session database.
741 *
742 * NB: We could pass in the size here; is it necessary?
743 */
744int
745start_session_db(void)
746{
747	if (session_db && (*session_db->close)(session_db))
748		emergency("session database close: %s", strerror(errno));
749	if ((session_db = dbopen(NULL, O_RDWR, 0, DB_HASH, NULL)) == 0) {
750		emergency("session database open: %s", strerror(errno));
751		return (1);
752	}
753	return (0);
754}
755
756/*
757 * Add a new login session.
758 */
759void
760add_session(session_t *sp)
761{
762	DBT key;
763	DBT data;
764
765	key.data = &sp->se_process;
766	key.size = sizeof sp->se_process;
767	data.data = &sp;
768	data.size = sizeof sp;
769
770	if ((*session_db->put)(session_db, &key, &data, 0))
771		emergency("insert %d: %s", sp->se_process, strerror(errno));
772}
773
774/*
775 * Delete an old login session.
776 */
777void
778del_session(session_t *sp)
779{
780	DBT key;
781
782	key.data = &sp->se_process;
783	key.size = sizeof sp->se_process;
784
785	if ((*session_db->del)(session_db, &key, 0))
786		emergency("delete %d: %s", sp->se_process, strerror(errno));
787}
788
789/*
790 * Look up a login session by pid.
791 */
792session_t *
793find_session(pid_t pid)
794{
795	DBT key;
796	DBT data;
797	session_t *ret;
798
799	key.data = &pid;
800	key.size = sizeof pid;
801	if ((*session_db->get)(session_db, &key, &data, 0) != 0)
802		return (0);
803	memcpy(&ret, data.data, sizeof(ret));
804	return (ret);
805}
806
807/*
808 * Construct an argument vector from a command line.
809 */
810char **
811construct_argv(char *command)
812{
813	int argc = 0;
814	char **argv = (char **) calloc((strlen(command) + 1) / 2 + 1,
815	    sizeof (char *));
816	static const char separators[] = " \t";
817
818	if (argv == NULL)
819		return (0);
820
821	if ((argv[argc++] = strtok(command, separators)) == 0) {
822		free(argv);
823		return (0);
824	}
825	while ((argv[argc++] = strtok(NULL, separators)))
826		continue;
827	return (argv);
828}
829
830/*
831 * Deallocate a session descriptor.
832 */
833void
834free_session(session_t *sp)
835{
836	free(sp->se_device);
837	if (sp->se_getty) {
838		free(sp->se_getty);
839		free(sp->se_getty_argv);
840	}
841	if (sp->se_window) {
842		free(sp->se_window);
843		free(sp->se_window_argv);
844	}
845	free(sp);
846}
847
848/*
849 * Allocate a new session descriptor.
850 */
851session_t *
852new_session(session_t *sprev, int session_index, struct ttyent *typ)
853{
854	session_t *sp;
855
856	if ((typ->ty_status & TTY_ON) == 0 ||
857	    typ->ty_name == 0 ||
858	    typ->ty_getty == 0)
859		return (0);
860
861	sp = (session_t *) malloc(sizeof (session_t));
862	memset(sp, 0, sizeof *sp);
863
864	sp->se_flags = SE_PRESENT;
865	sp->se_index = session_index;
866
867	if (asprintf(&sp->se_device, "%s%s", _PATH_DEV, typ->ty_name) == -1)
868		err(1, "asprintf");
869
870	if (setupargv(sp, typ) == 0) {
871		free_session(sp);
872		return (0);
873	}
874
875	sp->se_next = 0;
876	if (sprev == 0) {
877		sessions = sp;
878		sp->se_prev = 0;
879	} else {
880		sprev->se_next = sp;
881		sp->se_prev = sprev;
882	}
883
884	return (sp);
885}
886
887/*
888 * Calculate getty and if useful window argv vectors.
889 */
890int
891setupargv(session_t *sp, struct ttyent *typ)
892{
893	if (sp->se_getty) {
894		free(sp->se_getty);
895		free(sp->se_getty_argv);
896	}
897	if (asprintf(&sp->se_getty, "%s %s", typ->ty_getty, typ->ty_name) == -1)
898		err(1, "asprintf");
899	sp->se_getty_argv = construct_argv(sp->se_getty);
900	if (sp->se_getty_argv == 0) {
901		warning("can't parse getty for port %s", sp->se_device);
902		free(sp->se_getty);
903		sp->se_getty = 0;
904		return (0);
905	}
906	if (typ->ty_window) {
907		if (sp->se_window)
908			free(sp->se_window);
909		sp->se_window = strdup(typ->ty_window);
910		if (sp->se_window == NULL) {
911			warning("can't allocate window");
912			return (0);
913		}
914		sp->se_window_argv = construct_argv(sp->se_window);
915		if (sp->se_window_argv == NULL) {
916			warning("can't parse window for port %s",
917			    sp->se_device);
918			free(sp->se_window);
919			sp->se_window = NULL;
920			return (0);
921		}
922	}
923	return (1);
924}
925
926/*
927 * Walk the list of ttys and create sessions for each active line.
928 */
929state_func_t
930read_ttys(void)
931{
932	int session_index = 0;
933	session_t *sp, *snext;
934	struct ttyent *typ;
935
936	/*
937	 * Destroy any previous session state.
938	 * There shouldn't be any, but just in case...
939	 */
940	for (sp = sessions; sp; sp = snext) {
941		if (sp->se_process)
942			clear_session_logs(sp);
943		snext = sp->se_next;
944		free_session(sp);
945	}
946	sessions = 0;
947	if (start_session_db())
948		return (state_func_t) single_user;
949
950	/*
951	 * Allocate a session entry for each active port.
952	 * Note that sp starts at 0.
953	 */
954	while ((typ = getttyent()))
955		if ((snext = new_session(sp, ++session_index, typ)))
956			sp = snext;
957
958	endttyent();
959
960	return (state_func_t) multi_user;
961}
962
963/*
964 * Start a window system running.
965 */
966void
967start_window_system(session_t *sp)
968{
969	pid_t pid;
970	sigset_t mask;
971
972	if ((pid = fork()) == -1) {
973		emergency("can't fork for window system on port %s: %m",
974		    sp->se_device);
975		/* hope that getty fails and we can try again */
976		return;
977	}
978
979	if (pid)
980		return;
981
982	sigemptyset(&mask);
983	sigprocmask(SIG_SETMASK, &mask, NULL);
984
985	if (setsid() < 0)
986		emergency("setsid failed (window) %m");
987
988	setprocresources(RESOURCE_WINDOW);
989
990	execv(sp->se_window_argv[0], sp->se_window_argv);
991	stall("can't exec window system '%s' for port %s: %m",
992	    sp->se_window_argv[0], sp->se_device);
993	_exit(1);
994}
995
996/*
997 * Start a login session running.
998 * For first open, man-handle tty directly to determine if it
999 * really exists. It is not efficient to spawn gettys on devices
1000 * that do not exist.
1001 */
1002pid_t
1003start_getty(session_t *sp)
1004{
1005	pid_t pid;
1006	sigset_t mask;
1007	time_t current_time = time(NULL);
1008	int p[2], new = 1;
1009
1010	if (sp->se_flags & SE_DEVEXISTS)
1011		new = 0;
1012
1013	if (new) {
1014		if (pipe(p) == -1)
1015			return (-1);
1016	}
1017
1018	/*
1019	 * fork(), not vfork() -- we can't afford to block.
1020	 */
1021	if ((pid = fork()) == -1) {
1022		emergency("can't fork for getty on port %s: %m", sp->se_device);
1023		return (-1);
1024	}
1025
1026	if (pid) {
1027		if (new) {
1028			char c;
1029
1030			close(p[1]);
1031			if (read(p[0], &c, 1) != 1) {
1032				close(p[0]);
1033				return (-1);
1034			}
1035			close(p[0]);
1036			if (c == '1')
1037				sp->se_flags |= SE_DEVEXISTS;
1038			else
1039				sp->se_flags |= SE_SHUTDOWN;
1040		}
1041		return (pid);
1042	}
1043	if (new) {
1044		int fd;
1045
1046		close(p[0]);
1047		fd = open(sp->se_device, O_RDONLY | O_NONBLOCK, 0666);
1048		if (fd == -1 && (errno == ENXIO || errno == ENOENT ||
1049		    errno == EISDIR)) {
1050			(void)write(p[1], "0", 1);
1051			close(p[1]);
1052			_exit(1);
1053		}
1054		(void)write(p[1], "1", 1);
1055		close(p[1]);
1056		close(fd);
1057		sleep(1);
1058	}
1059
1060	if (current_time > sp->se_started &&
1061	    current_time - sp->se_started < GETTY_SPACING) {
1062		warning("getty repeating too quickly on port %s, sleeping",
1063		    sp->se_device);
1064		sleep((unsigned) GETTY_SLEEP);
1065	}
1066
1067	if (sp->se_window) {
1068		start_window_system(sp);
1069		sleep(WINDOW_WAIT);
1070	}
1071
1072	sigemptyset(&mask);
1073	sigprocmask(SIG_SETMASK, &mask, NULL);
1074
1075	setprocresources(RESOURCE_GETTY);
1076
1077	execv(sp->se_getty_argv[0], sp->se_getty_argv);
1078	stall("can't exec getty '%s' for port %s: %m",
1079	    sp->se_getty_argv[0], sp->se_device);
1080	_exit(1);
1081}
1082
1083/*
1084 * Collect exit status for a child.
1085 * If an exiting login, start a new login running.
1086 */
1087void
1088collect_child(pid_t pid)
1089{
1090	session_t *sp, *sprev, *snext;
1091
1092	if (sessions == NULL)
1093		return;
1094
1095	if ((sp = find_session(pid)) == NULL)
1096		return;
1097
1098	clear_session_logs(sp);
1099	login_fbtab(sp->se_device + sizeof(_PATH_DEV) - 1, 0, 0);
1100	del_session(sp);
1101	sp->se_process = 0;
1102
1103	if (sp->se_flags & SE_SHUTDOWN) {
1104		if ((sprev = sp->se_prev))
1105			sprev->se_next = sp->se_next;
1106		else
1107			sessions = sp->se_next;
1108		if ((snext = sp->se_next))
1109			snext->se_prev = sp->se_prev;
1110		free_session(sp);
1111		return;
1112	}
1113
1114	if ((pid = start_getty(sp)) == -1) {
1115		/* serious trouble */
1116		requested_transition = clean_ttys;
1117		return;
1118	}
1119
1120	sp->se_process = pid;
1121	sp->se_started = time(NULL);
1122	add_session(sp);
1123}
1124
1125/*
1126 * Catch a signal and request a state transition.
1127 */
1128void
1129transition_handler(int sig)
1130{
1131
1132	switch (sig) {
1133	case SIGHUP:
1134		requested_transition = clean_ttys;
1135		break;
1136	case SIGTERM:
1137		requested_transition = death;
1138		break;
1139	case SIGUSR1:
1140		requested_transition = nice_death;
1141		break;
1142	case SIGUSR2:
1143		requested_transition = hard_death;
1144		break;
1145	case SIGTSTP:
1146		requested_transition = catatonia;
1147		break;
1148	default:
1149		requested_transition = 0;
1150		break;
1151	}
1152}
1153
1154/*
1155 * Take the system multiuser.
1156 */
1157state_func_t
1158multi_user(void)
1159{
1160	pid_t pid;
1161	session_t *sp;
1162
1163	requested_transition = 0;
1164
1165	/*
1166	 * If the administrator has not set the security level to -1
1167	 * to indicate that the kernel should not run multiuser in secure
1168	 * mode, and the run script has not set a higher level of security
1169	 * than level 1, then put the kernel into secure mode.
1170	 */
1171	if (getsecuritylevel() == 0)
1172		setsecuritylevel(1);
1173
1174	for (sp = sessions; sp; sp = sp->se_next) {
1175		if (sp->se_process)
1176			continue;
1177		if ((pid = start_getty(sp)) == -1) {
1178			/* serious trouble */
1179			requested_transition = clean_ttys;
1180			break;
1181		}
1182		sp->se_process = pid;
1183		sp->se_started = time(NULL);
1184		add_session(sp);
1185	}
1186
1187	while (!requested_transition)
1188		if ((pid = waitpid(-1, NULL, 0)) != -1)
1189			collect_child(pid);
1190
1191	return (state_func_t) requested_transition;
1192}
1193
1194/*
1195 * This is an n-squared algorithm.  We hope it isn't run often...
1196 */
1197state_func_t
1198clean_ttys(void)
1199{
1200	session_t *sp, *sprev;
1201	struct ttyent *typ;
1202	int session_index = 0;
1203	int devlen;
1204
1205	for (sp = sessions; sp; sp = sp->se_next)
1206		sp->se_flags &= ~SE_PRESENT;
1207
1208	devlen = sizeof(_PATH_DEV) - 1;
1209	while ((typ = getttyent())) {
1210		++session_index;
1211
1212		for (sprev = 0, sp = sessions; sp; sprev = sp, sp = sp->se_next)
1213			if (strcmp(typ->ty_name, sp->se_device + devlen) == 0)
1214				break;
1215
1216		if (sp) {
1217			sp->se_flags |= SE_PRESENT;
1218			if (sp->se_index != session_index) {
1219				warning("port %s changed utmp index from %d to %d",
1220				    sp->se_device, sp->se_index,
1221				    session_index);
1222				sp->se_index = session_index;
1223			}
1224			if ((typ->ty_status & TTY_ON) == 0 ||
1225			    typ->ty_getty == 0) {
1226				sp->se_flags |= SE_SHUTDOWN;
1227				kill(sp->se_process, SIGHUP);
1228				continue;
1229			}
1230			sp->se_flags &= ~SE_SHUTDOWN;
1231			if (setupargv(sp, typ) == 0) {
1232				warning("can't parse getty for port %s",
1233				    sp->se_device);
1234				sp->se_flags |= SE_SHUTDOWN;
1235				kill(sp->se_process, SIGHUP);
1236			}
1237			continue;
1238		}
1239
1240		new_session(sprev, session_index, typ);
1241	}
1242
1243	endttyent();
1244
1245	for (sp = sessions; sp; sp = sp->se_next)
1246		if ((sp->se_flags & SE_PRESENT) == 0) {
1247			sp->se_flags |= SE_SHUTDOWN;
1248			kill(sp->se_process, SIGHUP);
1249		}
1250
1251	return (state_func_t) multi_user;
1252}
1253
1254/*
1255 * Block further logins.
1256 */
1257state_func_t
1258catatonia(void)
1259{
1260	session_t *sp;
1261
1262	for (sp = sessions; sp; sp = sp->se_next)
1263		sp->se_flags |= SE_SHUTDOWN;
1264
1265	return (state_func_t) multi_user;
1266}
1267
1268/*
1269 * Note SIGALRM.
1270 */
1271void
1272alrm_handler(int sig)
1273{
1274	clang = 1;
1275}
1276
1277int death_howto = RB_HALT;
1278
1279/*
1280 * Bring the system down nicely, then we must powerdown because something
1281 * is very wrong.
1282 */
1283state_func_t
1284hard_death(void)
1285{
1286	death_howto |= RB_POWERDOWN;
1287	return nice_death();
1288}
1289
1290/*
1291 * Bring the system down to single user nicely, after run the shutdown script.
1292 */
1293state_func_t
1294nice_death(void)
1295{
1296	session_t *sp;
1297	int i;
1298	pid_t pid;
1299	static const int death_sigs[3] = { SIGHUP, SIGTERM, SIGKILL };
1300	int status;
1301
1302#if CPU_LIDSUSPEND
1303	int lidsuspend_mib[] = {CTL_MACHDEP, CPU_LIDSUSPEND};
1304	int dontsuspend = 0;
1305
1306	if ((death_howto & RB_POWERDOWN) &&
1307	    (sysctl(lidsuspend_mib, 2, NULL, NULL, &dontsuspend,
1308		    sizeof(dontsuspend)) < 0))
1309			warning("cannot disable lid suspend");
1310	}
1311#endif
1312
1313	for (sp = sessions; sp; sp = sp->se_next) {
1314		sp->se_flags &= ~SE_PRESENT;
1315		sp->se_flags |= SE_SHUTDOWN;
1316		kill(sp->se_process, SIGHUP);
1317	}
1318
1319	/* terminate the accounting process */
1320	acct(NULL);
1321
1322	/* NB: should send a message to the session logger to avoid blocking. */
1323	logwtmp("~", "shutdown", "");
1324
1325	if (access(_PATH_RUNCOM, R_OK) != -1) {
1326		pid_t pid;
1327		struct sigaction sa;
1328
1329		switch ((pid = fork())) {
1330		case -1:
1331			break;
1332		case 0:
1333
1334			memset(&sa, 0, sizeof sa);
1335			sigemptyset(&sa.sa_mask);
1336			sa.sa_flags = 0;
1337			sa.sa_handler = SIG_IGN;
1338			(void) sigaction(SIGTSTP, &sa, NULL);
1339			(void) sigaction(SIGHUP, &sa, NULL);
1340
1341			setctty(_PATH_CONSOLE);
1342
1343			sigprocmask(SIG_SETMASK, &sa.sa_mask, NULL);
1344
1345			execl(_PATH_BSHELL, "sh", _PATH_RUNCOM, "shutdown",
1346			    (char *)NULL);
1347			stall("can't exec %s for %s %s: %m", _PATH_BSHELL,
1348			    _PATH_RUNCOM, "shutdown");
1349			_exit(1);
1350		default:
1351			waitpid(pid, &status, 0);
1352			if (WIFEXITED(status) && WEXITSTATUS(status) == 2)
1353				death_howto |= RB_POWERDOWN;
1354		}
1355	}
1356
1357	for (i = 0; i < 3; ++i) {
1358		if (kill(-1, death_sigs[i]) == -1 && errno == ESRCH)
1359			goto die;
1360
1361		clang = 0;
1362		alarm(DEATH_WATCH);
1363		do {
1364			if ((pid = waitpid(-1, NULL, 0)) != -1)
1365				collect_child(pid);
1366		} while (clang == 0 && errno != ECHILD);
1367
1368		if (errno == ECHILD)
1369			goto die;
1370	}
1371
1372	warning("some processes would not die; ps axl advised");
1373
1374die:
1375	reboot(death_howto);
1376
1377	/* ... and if that fails.. oh well */
1378	return (state_func_t) single_user;
1379}
1380
1381/*
1382 * Bring the system down to single user.
1383 */
1384state_func_t
1385death(void)
1386{
1387	session_t *sp;
1388	int i;
1389	pid_t pid;
1390	static const int death_sigs[3] = { SIGHUP, SIGTERM, SIGKILL };
1391
1392	/* terminate the accounting process */
1393	acct(NULL);
1394
1395	for (sp = sessions; sp; sp = sp->se_next)
1396		sp->se_flags |= SE_SHUTDOWN;
1397
1398	/* NB: should send a message to the session logger to avoid blocking. */
1399	logwtmp("~", "shutdown", "");
1400
1401	for (i = 0; i < 3; ++i) {
1402		if (kill(-1, death_sigs[i]) == -1 && errno == ESRCH)
1403			return (state_func_t) single_user;
1404
1405		clang = 0;
1406		alarm(DEATH_WATCH);
1407		do {
1408			if ((pid = waitpid(-1, NULL, 0)) != -1)
1409				collect_child(pid);
1410		} while (clang == 0 && errno != ECHILD);
1411
1412		if (errno == ECHILD)
1413			return (state_func_t) single_user;
1414	}
1415
1416	warning("some processes would not die; ps axl advised");
1417
1418	return (state_func_t) single_user;
1419}
1420
1421#ifdef LOGIN_CAP
1422void
1423setprocresources(char *class)
1424{
1425	login_cap_t *lc;
1426
1427	if ((lc = login_getclass(class)) != NULL) {
1428		setusercontext(lc, NULL, 0,
1429		    LOGIN_SETPRIORITY|LOGIN_SETRESOURCES|LOGIN_SETUMASK);
1430		login_close(lc);
1431	}
1432}
1433#endif
1434