init.c revision 1.31 
1/*	$OpenBSD: init.c,v 1.31 2003/03/30 18:09:44 deraadt 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. All advertising materials mentioning features or use of this software
20 *    must display the following acknowledgement:
21 *	This product includes software developed by the University of
22 *	California, Berkeley and its contributors.
23 * 4. Neither the name of the University nor the names of its contributors
24 *    may be used to endorse or promote products derived from this software
25 *    without specific prior written permission.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37 * SUCH DAMAGE.
38 */
39
40#ifndef lint
41static char copyright[] =
42"@(#) Copyright (c) 1991, 1993\n\
43	The Regents of the University of California.  All rights reserved.\n";
44#endif /* not lint */
45
46#ifndef lint
47#if 0
48static char sccsid[] = "@(#)init.c	8.2 (Berkeley) 4/28/95";
49#else
50static char rcsid[] = "$OpenBSD: init.c,v 1.31 2003/03/30 18:09:44 deraadt Exp $";
51#endif
52#endif /* not lint */
53
54#include <sys/param.h>
55#include <sys/sysctl.h>
56#include <sys/wait.h>
57#include <sys/reboot.h>
58
59#include <db.h>
60#include <errno.h>
61#include <fcntl.h>
62#include <signal.h>
63#include <stdarg.h>
64#include <stdio.h>
65#include <stdlib.h>
66#include <string.h>
67#include <syslog.h>
68#include <time.h>
69#include <ttyent.h>
70#include <unistd.h>
71#include <util.h>
72
73#ifdef SECURE
74#include <pwd.h>
75#endif
76
77#ifdef LOGIN_CAP
78#include <login_cap.h>
79#endif
80
81#include "pathnames.h"
82
83/*
84 * Sleep times; used to prevent thrashing.
85 */
86#define	GETTY_SPACING		 5	/* N secs minimum getty spacing */
87#define	GETTY_SLEEP		30	/* sleep N secs after spacing problem */
88#define	WINDOW_WAIT		 3	/* wait N secs after starting window */
89#define	STALL_TIMEOUT		30	/* wait N secs after warning */
90#define	DEATH_WATCH		10	/* wait N secs for procs to die */
91
92/*
93 * User-based resource limits.
94 */
95#define RESOURCE_RC		"daemon"
96#define RESOURCE_WINDOW		"default"
97#define RESOURCE_GETTY		"default"
98
99#ifndef DEFAULT_STATE
100#define DEFAULT_STATE		runcom
101#endif
102
103void handle(sig_t, ...);
104void delset(sigset_t *, ...);
105
106void stall(char *, ...);
107void warning(char *, ...);
108void emergency(char *, ...);
109void disaster(int);
110void badsys(int);
111
112/*
113 * We really need a recursive typedef...
114 * The following at least guarantees that the return type of (*state_t)()
115 * is sufficiently wide to hold a function pointer.
116 */
117typedef long (*state_func_t)(void);
118typedef state_func_t (*state_t)(void);
119
120state_func_t single_user(void);
121state_func_t runcom(void);
122state_func_t read_ttys(void);
123state_func_t multi_user(void);
124state_func_t clean_ttys(void);
125state_func_t catatonia(void);
126state_func_t death(void);
127state_func_t nice_death(void);
128
129enum { AUTOBOOT, FASTBOOT } runcom_mode = AUTOBOOT;
130
131void transition(state_t);
132state_t requested_transition = DEFAULT_STATE;
133
134void setctty(char *);
135
136typedef struct init_session {
137	int	se_index;		/* index of entry in ttys file */
138	pid_t	se_process;		/* controlling process */
139	time_t	se_started;		/* used to avoid thrashing */
140	int	se_flags;		/* status of session */
141#define	SE_SHUTDOWN	0x1		/* session won't be restarted */
142#define	SE_PRESENT	0x2		/* session is in /etc/ttys */
143#define	SE_DEVEXISTS	0x4		/* open does not result in ENODEV */
144	char	*se_device;		/* filename of port */
145	char	*se_getty;		/* what to run on that port */
146	char	**se_getty_argv;	/* pre-parsed argument array */
147	char	*se_window;		/* window system (started only once) */
148	char	**se_window_argv;	/* pre-parsed argument array */
149	struct	init_session *se_prev;
150	struct	init_session *se_next;
151} session_t;
152
153void free_session(session_t *);
154session_t *new_session(session_t *, int, struct ttyent *);
155session_t *sessions;
156
157char **construct_argv(char *);
158void start_window_system(session_t *);
159void collect_child(pid_t);
160pid_t start_getty(session_t *);
161void transition_handler(int);
162void alrm_handler(int);
163void setsecuritylevel(int);
164int getsecuritylevel(void);
165int setupargv(session_t *, struct ttyent *);
166int clang;
167
168#ifdef LOGIN_CAP
169void setprocresources(char *);
170#else
171#define setprocresources(p)
172#endif
173
174void clear_session_logs(session_t *);
175
176int start_session_db(void);
177void add_session(session_t *);
178void del_session(session_t *);
179session_t *find_session(pid_t);
180DB *session_db;
181
182/*
183 * The mother of all processes.
184 */
185int
186main(int argc, char *argv[])
187{
188	int c;
189	struct sigaction sa;
190	sigset_t mask;
191
192	/* Dispose of random users. */
193	if (getuid() != 0) {
194		(void)fprintf(stderr, "init: %s\n", strerror(EPERM));
195		exit (1);
196	}
197
198	/* System V users like to reexec init. */
199	if (getpid() != 1) {
200		(void)fprintf(stderr, "init: already running\n");
201		exit (1);
202	}
203
204	/*
205	 * Note that this does NOT open a file...
206	 * Does 'init' deserve its own facility number?
207	 */
208	openlog("init", LOG_CONS|LOG_ODELAY, LOG_AUTH);
209
210	/*
211	 * Create an initial session.
212	 */
213	if (setsid() < 0)
214		warning("initial setsid() failed: %m");
215
216	/*
217	 * Establish an initial user so that programs running
218	 * single user do not freak out and die (like passwd).
219	 */
220	if (setlogin("root") < 0)
221		warning("setlogin() failed: %m");
222
223	/*
224	 * This code assumes that we always get arguments through flags,
225	 * never through bits set in some random machine register.
226	 */
227	while ((c = getopt(argc, argv, "sf")) != -1)
228		switch (c) {
229		case 's':
230			requested_transition = single_user;
231			break;
232		case 'f':
233			runcom_mode = FASTBOOT;
234			break;
235		default:
236			warning("unrecognized flag '-%c'", c);
237			break;
238		}
239
240	if (optind != argc)
241		warning("ignoring excess arguments");
242
243	/*
244	 * We catch or block signals rather than ignore them,
245	 * so that they get reset on exec.
246	 */
247	handle(badsys, SIGSYS, 0);
248	handle(disaster, SIGABRT, SIGFPE, SIGILL, SIGSEGV,
249	       SIGBUS, SIGXCPU, SIGXFSZ, 0);
250	handle(transition_handler, SIGHUP, SIGTERM, SIGTSTP, SIGUSR1, 0);
251	handle(alrm_handler, SIGALRM, 0);
252	sigfillset(&mask);
253	delset(&mask, SIGABRT, SIGFPE, SIGILL, SIGSEGV, SIGBUS, SIGSYS,
254		SIGXCPU, SIGXFSZ, SIGHUP, SIGTERM, SIGUSR1, SIGTSTP, SIGALRM, 0);
255	sigprocmask(SIG_SETMASK, &mask, NULL);
256	memset(&sa, 0, sizeof sa);
257	sigemptyset(&sa.sa_mask);
258	sa.sa_flags = 0;
259	sa.sa_handler = SIG_IGN;
260	(void) sigaction(SIGTTIN, &sa, NULL);
261	(void) sigaction(SIGTTOU, &sa, NULL);
262
263	/*
264	 * Paranoia.
265	 */
266	close(STDIN_FILENO);
267	close(STDOUT_FILENO);
268	close(STDERR_FILENO);
269
270	/*
271	 * Start the state machine.
272	 */
273	transition(requested_transition);
274
275	/*
276	 * Should never reach here.
277	 */
278	exit(1);
279}
280
281/*
282 * Associate a function with a signal handler.
283 */
284void
285handle(sig_t handler, ...)
286{
287	int sig;
288	struct sigaction sa;
289	sigset_t mask_everything;
290	va_list ap;
291
292	va_start(ap, handler);
293
294	memset(&sa, 0, sizeof sa);
295	sa.sa_handler = handler;
296	sigfillset(&mask_everything);
297
298	while ((sig = va_arg(ap, int))) {
299		sa.sa_mask = mask_everything;
300		/* XXX SA_RESTART? */
301		sa.sa_flags = sig == SIGCHLD ? SA_NOCLDSTOP : 0;
302		sigaction(sig, &sa, NULL);
303	}
304	va_end(ap);
305}
306
307/*
308 * Delete a set of signals from a mask.
309 */
310void
311delset(sigset_t *maskp, ...)
312{
313	int sig;
314	va_list ap;
315
316	va_start(ap, maskp);
317	while ((sig = va_arg(ap, int)))
318		sigdelset(maskp, sig);
319	va_end(ap);
320}
321
322/*
323 * Log a message and sleep for a while (to give someone an opportunity
324 * to read it and to save log or hardcopy output if the problem is chronic).
325 * NB: should send a message to the session logger to avoid blocking.
326 */
327void
328stall(char *message, ...)
329{
330	va_list ap;
331
332	va_start(ap, message);
333	vsyslog(LOG_ALERT, message, ap);
334	va_end(ap);
335	closelog();
336	sleep(STALL_TIMEOUT);
337}
338
339/*
340 * Like stall(), but doesn't sleep.
341 * If cpp had variadic macros, the two functions could be #defines for another.
342 * NB: should send a message to the session logger to avoid blocking.
343 */
344void
345warning(char *message, ...)
346{
347	va_list ap;
348
349	va_start(ap, message);
350	vsyslog(LOG_ALERT, message, ap);
351	va_end(ap);
352	closelog();
353}
354
355/*
356 * Log an emergency message.
357 * NB: should send a message to the session logger to avoid blocking.
358 */
359void
360emergency(char *message, ...)
361{
362	struct syslog_data sdata = SYSLOG_DATA_INIT;
363	va_list ap;
364
365	va_start(ap, message);
366	vsyslog_r(LOG_EMERG, &sdata, message, ap);
367	va_end(ap);
368}
369
370/*
371 * Catch a SIGSYS signal.
372 *
373 * These may arise if a system does not support sysctl.
374 * We tolerate up to 25 of these, then throw in the towel.
375 */
376void
377badsys(int sig)
378{
379	static int badcount = 0;
380
381	if (badcount++ < 25)
382		return;
383	disaster(sig);
384}
385
386/*
387 * Catch an unexpected signal.
388 */
389void
390disaster(int sig)
391{
392	emergency("fatal signal: %s", strsignal(sig));
393
394	sleep(STALL_TIMEOUT);
395	_exit(sig);		/* reboot */
396}
397
398/*
399 * Get the security level of the kernel.
400 */
401int
402getsecuritylevel(void)
403{
404#ifdef KERN_SECURELVL
405	int name[2], curlevel;
406	size_t len;
407
408	name[0] = CTL_KERN;
409	name[1] = KERN_SECURELVL;
410	len = sizeof curlevel;
411	if (sysctl(name, 2, &curlevel, &len, NULL, 0) == -1) {
412		emergency("cannot get kernel security level: %s",
413		    strerror(errno));
414		return (-1);
415	}
416	return (curlevel);
417#else
418	return (-1);
419#endif
420}
421
422/*
423 * Set the security level of the kernel.
424 */
425void
426setsecuritylevel(int newlevel)
427{
428#ifdef KERN_SECURELVL
429	int name[2], curlevel;
430	extern int errno;
431
432	curlevel = getsecuritylevel();
433	if (newlevel == curlevel)
434		return;
435	name[0] = CTL_KERN;
436	name[1] = KERN_SECURELVL;
437	if (sysctl(name, 2, NULL, NULL, &newlevel, sizeof newlevel) == -1) {
438		emergency(
439		    "cannot change kernel security level from %d to %d: %s",
440		    curlevel, newlevel, strerror(errno));
441		return;
442	}
443#ifdef SECURE
444	warning("kernel security level changed from %d to %d",
445	    curlevel, newlevel);
446#endif
447#endif
448}
449
450/*
451 * Change states in the finite state machine.
452 * The initial state is passed as an argument.
453 */
454void
455transition(state_t s)
456{
457	for (;;)
458		s = (state_t) (*s)();
459}
460
461/*
462 * Close out the accounting files for a login session.
463 * NB: should send a message to the session logger to avoid blocking.
464 */
465void
466clear_session_logs(session_t *sp)
467{
468	char *line = sp->se_device + sizeof(_PATH_DEV) - 1;
469
470	if (logout(line))
471		logwtmp(line, "", "");
472}
473
474/*
475 * Start a session and allocate a controlling terminal.
476 * Only called by children of init after forking.
477 */
478void
479setctty(char *name)
480{
481	int fd;
482
483	(void) revoke(name);
484	sleep(2);			/* leave DTR low */
485	if ((fd = open(name, O_RDWR)) == -1) {
486		stall("can't open %s: %m", name);
487		_exit(1);
488	}
489	if (login_tty(fd) == -1) {
490		stall("can't get %s for controlling terminal: %m", name);
491		_exit(1);
492	}
493}
494
495/*
496 * Bring the system up single user.
497 */
498state_func_t
499single_user(void)
500{
501	pid_t pid, wpid;
502	int status;
503	sigset_t mask;
504	char shell[MAXPATHLEN];		/* Allocate space here */
505	char name[MAXPATHLEN];		/* Name (argv[0]) of shell */
506	char *argv[2];
507#ifdef SECURE
508	struct ttyent *typ;
509	struct passwd *pp;
510	static const char banner[] =
511		"Enter root password, or ^D to go multi-user\n";
512	char *clear, *password;
513#endif
514
515	/* Init shell and name */
516	strlcpy(shell, _PATH_BSHELL, sizeof shell);
517	strlcpy(name, "-sh", sizeof name);
518
519	/*
520	 * If the kernel is in secure mode, downgrade it to insecure mode.
521	 */
522	if (getsecuritylevel() > 0)
523		setsecuritylevel(0);
524
525	if ((pid = fork()) == 0) {
526		/*
527		 * Start the single user session.
528		 */
529		setctty(_PATH_CONSOLE);
530
531#ifdef SECURE
532		/*
533		 * Check the root password.
534		 * We don't care if the console is 'on' by default;
535		 * it's the only tty that can be 'off' and 'secure'.
536		 */
537		typ = getttynam("console");
538		pp = getpwnam("root");
539		if (typ && (typ->ty_status & TTY_SECURE) == 0 && pp &&
540		    *pp->pw_passwd) {
541			write(STDERR_FILENO, banner, sizeof banner - 1);
542			for (;;) {
543				clear = getpass("Password:");
544				if (clear == 0 || *clear == '\0')
545					_exit(0);
546				password = crypt(clear, pp->pw_passwd);
547				memset(clear, 0, _PASSWORD_LEN);
548				if (strcmp(password, pp->pw_passwd) == 0)
549					break;
550				warning("single-user login failed\n");
551			}
552		}
553		endttyent();
554		endpwent();
555#endif /* SECURE */
556
557#ifdef DEBUGSHELL
558		{
559			char altshell[128], *cp = altshell;
560			int num;
561
562#define	SHREQUEST \
563	"Enter pathname of shell or RETURN for sh: "
564
565			(void)write(STDERR_FILENO,
566			    SHREQUEST, sizeof(SHREQUEST) - 1);
567			while ((num = read(STDIN_FILENO, cp, 1)) != -1 &&
568			    num != 0 && *cp != '\n' && cp < &altshell[127])
569				cp++;
570			*cp = '\0';
571
572			/* Copy in alternate shell */
573			if (altshell[0] != '\0'){
574				char *p;
575
576				/* Binary to exec */
577				strlcpy(shell, altshell, sizeof shell);
578
579				/* argv[0] */
580				p = strrchr(altshell, '/');
581				if(p == NULL) p = altshell;
582				else p++;
583
584				name[0] = '-';
585				strlcpy(&name[1], p, sizeof name -1);
586			}
587		}
588#endif /* DEBUGSHELL */
589
590		/*
591		 * Unblock signals.
592		 * We catch all the interesting ones,
593		 * and those are reset to SIG_DFL on exec.
594		 */
595		sigemptyset(&mask);
596		sigprocmask(SIG_SETMASK, &mask, NULL);
597
598		/*
599		 * Fire off a shell.
600		 * If the default one doesn't work, try the Bourne shell.
601		 */
602		argv[0] = name;
603		argv[1] = NULL;
604		setenv("PATH", _PATH_STDPATH, 1);
605		execv(shell, argv);
606		emergency("can't exec %s for single user: %m", shell);
607
608		argv[0] = "-sh";
609		argv[1] = NULL;
610		execv(_PATH_BSHELL, argv);
611		emergency("can't exec %s for single user: %m", _PATH_BSHELL);
612		sleep(STALL_TIMEOUT);
613		_exit(1);
614	}
615
616	if (pid == -1) {
617		/*
618		 * We are seriously hosed.  Do our best.
619		 */
620		emergency("can't fork single-user shell, trying again");
621		while (waitpid(-1, NULL, WNOHANG) > 0)
622			continue;
623		return (state_func_t) single_user;
624	}
625
626	requested_transition = 0;
627	do {
628		if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1)
629			collect_child(wpid);
630		if (wpid == -1) {
631			if (errno == EINTR)
632				continue;
633			warning("wait for single-user shell failed: %m; restarting");
634			return (state_func_t) single_user;
635		}
636		if (wpid == pid && WIFSTOPPED(status)) {
637			warning("init: shell stopped, restarting\n");
638			kill(pid, SIGCONT);
639			wpid = -1;
640		}
641	} while (wpid != pid && !requested_transition);
642
643	if (requested_transition)
644		return (state_func_t) requested_transition;
645
646	if (!WIFEXITED(status)) {
647		if (WTERMSIG(status) == SIGKILL) {
648			/*
649			 *  reboot(8) killed shell?
650			 */
651			warning("single user shell terminated.");
652			sleep(STALL_TIMEOUT);
653			_exit(0);
654		} else {
655			warning("single user shell terminated, restarting");
656			return (state_func_t) single_user;
657		}
658	}
659
660	runcom_mode = FASTBOOT;
661	return (state_func_t) runcom;
662}
663
664/*
665 * Run the system startup script.
666 */
667state_func_t
668runcom(void)
669{
670	pid_t pid, wpid;
671	int status;
672	char *argv[4];
673	struct sigaction sa;
674
675	if ((pid = fork()) == 0) {
676		memset(&sa, 0, sizeof sa);
677		sigemptyset(&sa.sa_mask);
678		sa.sa_flags = 0;
679		sa.sa_handler = SIG_IGN;
680		(void) sigaction(SIGTSTP, &sa, NULL);
681		(void) sigaction(SIGHUP, &sa, NULL);
682
683		setctty(_PATH_CONSOLE);
684
685		argv[0] = "sh";
686		argv[1] = _PATH_RUNCOM;
687		argv[2] = runcom_mode == AUTOBOOT ? "autoboot" : 0;
688		argv[3] = 0;
689
690		sigprocmask(SIG_SETMASK, &sa.sa_mask, NULL);
691
692		setprocresources(RESOURCE_RC);
693
694		execv(_PATH_BSHELL, argv);
695		stall("can't exec %s for %s: %m", _PATH_BSHELL, _PATH_RUNCOM);
696		_exit(1);	/* force single user mode */
697	}
698
699	if (pid == -1) {
700		emergency("can't fork for %s on %s: %m",
701			_PATH_BSHELL, _PATH_RUNCOM);
702		while (waitpid(-1, NULL, WNOHANG) > 0)
703			continue;
704		sleep(STALL_TIMEOUT);
705		return (state_func_t) single_user;
706	}
707
708	/*
709	 * Copied from single_user().  This is a bit paranoid.
710	 */
711	do {
712		if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1)
713			collect_child(wpid);
714		if (wpid == -1) {
715			if (errno == EINTR)
716				continue;
717			warning("wait for %s on %s failed: %m; going to single user mode",
718				_PATH_BSHELL, _PATH_RUNCOM);
719			return (state_func_t) single_user;
720		}
721		if (wpid == pid && WIFSTOPPED(status)) {
722			warning("init: %s on %s stopped, restarting\n",
723				_PATH_BSHELL, _PATH_RUNCOM);
724			kill(pid, SIGCONT);
725			wpid = -1;
726		}
727	} while (wpid != pid);
728
729	if (WIFSIGNALED(status) && WTERMSIG(status) == SIGTERM &&
730	    requested_transition == catatonia) {
731		/* /etc/rc executed /sbin/reboot; wait for the end quietly */
732		sigset_t s;
733
734		sigfillset(&s);
735		for (;;)
736			sigsuspend(&s);
737	}
738
739	if (!WIFEXITED(status)) {
740		warning("%s on %s terminated abnormally, going to single user mode",
741			_PATH_BSHELL, _PATH_RUNCOM);
742		return (state_func_t) single_user;
743	}
744
745	if (WEXITSTATUS(status))
746		return (state_func_t) single_user;
747
748	runcom_mode = AUTOBOOT;		/* the default */
749	/* NB: should send a message to the session logger to avoid blocking. */
750	logwtmp("~", "reboot", "");
751	return (state_func_t) read_ttys;
752}
753
754/*
755 * Open the session database.
756 *
757 * NB: We could pass in the size here; is it necessary?
758 */
759int
760start_session_db(void)
761{
762	if (session_db && (*session_db->close)(session_db))
763		emergency("session database close: %s", strerror(errno));
764	if ((session_db = dbopen(NULL, O_RDWR, 0, DB_HASH, NULL)) == 0) {
765		emergency("session database open: %s", strerror(errno));
766		return (1);
767	}
768	return (0);
769}
770
771/*
772 * Add a new login session.
773 */
774void
775add_session(session_t *sp)
776{
777	DBT key;
778	DBT data;
779
780	key.data = &sp->se_process;
781	key.size = sizeof sp->se_process;
782	data.data = &sp;
783	data.size = sizeof sp;
784
785	if ((*session_db->put)(session_db, &key, &data, 0))
786		emergency("insert %d: %s", sp->se_process, strerror(errno));
787}
788
789/*
790 * Delete an old login session.
791 */
792void
793del_session(session_t *sp)
794{
795	DBT key;
796
797	key.data = &sp->se_process;
798	key.size = sizeof sp->se_process;
799
800	if ((*session_db->del)(session_db, &key, 0))
801		emergency("delete %d: %s", sp->se_process, strerror(errno));
802}
803
804/*
805 * Look up a login session by pid.
806 */
807session_t *
808find_session(pid_t pid)
809{
810	DBT key;
811	DBT data;
812	session_t *ret;
813
814	key.data = &pid;
815	key.size = sizeof pid;
816	if ((*session_db->get)(session_db, &key, &data, 0) != 0)
817		return (0);
818	memcpy(&ret, data.data, sizeof(ret));
819	return (ret);
820}
821
822/*
823 * Construct an argument vector from a command line.
824 */
825char **
826construct_argv(char *command)
827{
828	int argc = 0;
829	char **argv = (char **) malloc(((strlen(command) + 1) / 2 + 1)
830						* sizeof (char *));
831	static const char separators[] = " \t";
832
833	if ((argv[argc++] = strtok(command, separators)) == 0)
834		return (0);
835	while ((argv[argc++] = strtok(NULL, separators)))
836		continue;
837	return (argv);
838}
839
840/*
841 * Deallocate a session descriptor.
842 */
843void
844free_session(session_t *sp)
845{
846	free(sp->se_device);
847	if (sp->se_getty) {
848		free(sp->se_getty);
849		free(sp->se_getty_argv);
850	}
851	if (sp->se_window) {
852		free(sp->se_window);
853		free(sp->se_window_argv);
854	}
855	free(sp);
856}
857
858/*
859 * Allocate a new session descriptor.
860 */
861session_t *
862new_session(session_t *sprev, int session_index, struct ttyent *typ)
863{
864	session_t *sp;
865	size_t len;
866
867	if ((typ->ty_status & TTY_ON) == 0 ||
868	    typ->ty_name == 0 ||
869	    typ->ty_getty == 0)
870		return (0);
871
872	sp = (session_t *) malloc(sizeof (session_t));
873	memset(sp, 0, sizeof *sp);
874
875	sp->se_flags = SE_PRESENT;
876	sp->se_index = session_index;
877
878	len = sizeof(_PATH_DEV) + strlen(typ->ty_name);
879	sp->se_device = malloc(len);
880	(void) snprintf(sp->se_device, len, "%s%s", _PATH_DEV, typ->ty_name);
881
882	if (setupargv(sp, typ) == 0) {
883		free_session(sp);
884		return (0);
885	}
886
887	sp->se_next = 0;
888	if (sprev == 0) {
889		sessions = sp;
890		sp->se_prev = 0;
891	} else {
892		sprev->se_next = sp;
893		sp->se_prev = sprev;
894	}
895
896	return (sp);
897}
898
899/*
900 * Calculate getty and if useful window argv vectors.
901 */
902int
903setupargv(session_t *sp, struct ttyent *typ)
904{
905	size_t len;
906
907	if (sp->se_getty) {
908		free(sp->se_getty);
909		free(sp->se_getty_argv);
910	}
911	len = strlen(typ->ty_getty) + strlen(typ->ty_name) + 2;
912	sp->se_getty = malloc(len);
913	(void) snprintf(sp->se_getty, len, "%s %s", typ->ty_getty, typ->ty_name);
914	sp->se_getty_argv = construct_argv(sp->se_getty);
915	if (sp->se_getty_argv == 0) {
916		warning("can't parse getty for port %s", sp->se_device);
917		free(sp->se_getty);
918		sp->se_getty = 0;
919		return (0);
920	}
921	if (typ->ty_window) {
922		if (sp->se_window)
923			free(sp->se_window);
924		sp->se_window = strdup(typ->ty_window);
925		sp->se_window_argv = construct_argv(sp->se_window);
926		if (sp->se_window_argv == 0) {
927			warning("can't parse window for port %s",
928				sp->se_device);
929			free(sp->se_window);
930			sp->se_window = 0;
931			return (0);
932		}
933	}
934	return (1);
935}
936
937/*
938 * Walk the list of ttys and create sessions for each active line.
939 */
940state_func_t
941read_ttys(void)
942{
943	int session_index = 0;
944	session_t *sp, *snext;
945	struct ttyent *typ;
946
947	/*
948	 * Destroy any previous session state.
949	 * There shouldn't be any, but just in case...
950	 */
951	for (sp = sessions; sp; sp = snext) {
952		if (sp->se_process)
953			clear_session_logs(sp);
954		snext = sp->se_next;
955		free_session(sp);
956	}
957	sessions = 0;
958	if (start_session_db())
959		return (state_func_t) single_user;
960
961	/*
962	 * Allocate a session entry for each active port.
963	 * Note that sp starts at 0.
964	 */
965	while ((typ = getttyent()))
966		if ((snext = new_session(sp, ++session_index, typ)))
967			sp = snext;
968
969	endttyent();
970
971	return (state_func_t) multi_user;
972}
973
974/*
975 * Start a window system running.
976 */
977void
978start_window_system(session_t *sp)
979{
980	pid_t pid;
981	sigset_t mask;
982
983	if ((pid = fork()) == -1) {
984		emergency("can't fork for window system on port %s: %m",
985			sp->se_device);
986		/* hope that getty fails and we can try again */
987		return;
988	}
989
990	if (pid)
991		return;
992
993	sigemptyset(&mask);
994	sigprocmask(SIG_SETMASK, &mask, NULL);
995
996	if (setsid() < 0)
997		emergency("setsid failed (window) %m");
998
999	setprocresources(RESOURCE_WINDOW);
1000
1001	execv(sp->se_window_argv[0], sp->se_window_argv);
1002	stall("can't exec window system '%s' for port %s: %m",
1003		sp->se_window_argv[0], sp->se_device);
1004	_exit(1);
1005}
1006
1007/*
1008 * Start a login session running.
1009 * For first open, man-handle tty directly to determine if it
1010 * really exists. It is not efficient to spawn gettys on devices
1011 * that do not exist.
1012 */
1013pid_t
1014start_getty(session_t *sp)
1015{
1016	pid_t pid;
1017	sigset_t mask;
1018	time_t current_time = time(NULL);
1019	int p[2], new = 1;
1020
1021	if (sp->se_flags & SE_DEVEXISTS)
1022		new = 0;
1023
1024	if (new) {
1025		if (pipe(p) == -1)
1026			return (-1);
1027	}
1028
1029	/*
1030	 * fork(), not vfork() -- we can't afford to block.
1031	 */
1032	if ((pid = fork()) == -1) {
1033		emergency("can't fork for getty on port %s: %m", sp->se_device);
1034		return (-1);
1035	}
1036
1037	if (pid) {
1038		if (new) {
1039			char c;
1040
1041			close(p[1]);
1042			if (read(p[0], &c, 1) != 1) {
1043				close(p[0]);
1044				return (-1);
1045			}
1046			close(p[0]);
1047			if (c == '1')
1048				sp->se_flags |= SE_DEVEXISTS;
1049			else
1050				sp->se_flags |= SE_SHUTDOWN;
1051		}
1052		return (pid);
1053	}
1054	if (new) {
1055		int fd;
1056
1057		close(p[0]);
1058		fd = open(sp->se_device, O_RDONLY | O_NONBLOCK, 0666);
1059		if (fd == -1 && (errno == ENXIO || errno == ENOENT ||
1060		    errno == EISDIR)) {
1061			(void)write(p[1], "0", 1);
1062			close(p[1]);
1063			_exit(1);
1064		}
1065		(void)write(p[1], "1", 1);
1066		close(p[1]);
1067		close(fd);
1068		sleep(1);
1069	}
1070
1071	if (current_time > sp->se_started &&
1072	    current_time - sp->se_started < GETTY_SPACING) {
1073		warning("getty repeating too quickly on port %s, sleeping",
1074		        sp->se_device);
1075		sleep((unsigned) GETTY_SLEEP);
1076	}
1077
1078	if (sp->se_window) {
1079		start_window_system(sp);
1080		sleep(WINDOW_WAIT);
1081	}
1082
1083	sigemptyset(&mask);
1084	sigprocmask(SIG_SETMASK, &mask, NULL);
1085
1086	setprocresources(RESOURCE_GETTY);
1087
1088	execv(sp->se_getty_argv[0], sp->se_getty_argv);
1089	stall("can't exec getty '%s' for port %s: %m",
1090		sp->se_getty_argv[0], sp->se_device);
1091	_exit(1);
1092}
1093
1094/*
1095 * Collect exit status for a child.
1096 * If an exiting login, start a new login running.
1097 */
1098void
1099collect_child(pid_t pid)
1100{
1101	session_t *sp, *sprev, *snext;
1102
1103	if (sessions == NULL)
1104		return;
1105
1106	if ((sp = find_session(pid)) == NULL)
1107		return;
1108
1109	clear_session_logs(sp);
1110	login_fbtab(sp->se_device + sizeof(_PATH_DEV) - 1, 0, 0);
1111	del_session(sp);
1112	sp->se_process = 0;
1113
1114	if (sp->se_flags & SE_SHUTDOWN) {
1115		if ((sprev = sp->se_prev))
1116			sprev->se_next = sp->se_next;
1117		else
1118			sessions = sp->se_next;
1119		if ((snext = sp->se_next))
1120			snext->se_prev = sp->se_prev;
1121		free_session(sp);
1122		return;
1123	}
1124
1125	if ((pid = start_getty(sp)) == -1) {
1126		/* serious trouble */
1127		requested_transition = clean_ttys;
1128		return;
1129	}
1130
1131	sp->se_process = pid;
1132	sp->se_started = time(NULL);
1133	add_session(sp);
1134}
1135
1136/*
1137 * Catch a signal and request a state transition.
1138 */
1139void
1140transition_handler(int sig)
1141{
1142
1143	switch (sig) {
1144	case SIGHUP:
1145		requested_transition = clean_ttys;
1146		break;
1147	case SIGTERM:
1148		requested_transition = death;
1149		break;
1150	case SIGUSR1:
1151		requested_transition = nice_death;
1152		break;
1153	case SIGTSTP:
1154		requested_transition = catatonia;
1155		break;
1156	default:
1157		requested_transition = 0;
1158		break;
1159	}
1160}
1161
1162/*
1163 * Take the system multiuser.
1164 */
1165state_func_t
1166multi_user(void)
1167{
1168	pid_t pid;
1169	session_t *sp;
1170
1171	requested_transition = 0;
1172
1173	/*
1174	 * If the administrator has not set the security level to -1
1175	 * to indicate that the kernel should not run multiuser in secure
1176	 * mode, and the run script has not set a higher level of security
1177	 * than level 1, then put the kernel into secure mode.
1178	 */
1179	if (getsecuritylevel() == 0)
1180		setsecuritylevel(1);
1181
1182	for (sp = sessions; sp; sp = sp->se_next) {
1183		if (sp->se_process)
1184			continue;
1185		if ((pid = start_getty(sp)) == -1) {
1186			/* serious trouble */
1187			requested_transition = clean_ttys;
1188			break;
1189		}
1190		sp->se_process = pid;
1191		sp->se_started = time(NULL);
1192		add_session(sp);
1193	}
1194
1195	while (!requested_transition)
1196		if ((pid = waitpid(-1, NULL, 0)) != -1)
1197			collect_child(pid);
1198
1199	return (state_func_t) requested_transition;
1200}
1201
1202/*
1203 * This is an n-squared algorithm.  We hope it isn't run often...
1204 */
1205state_func_t
1206clean_ttys(void)
1207{
1208	session_t *sp, *sprev;
1209	struct ttyent *typ;
1210	int session_index = 0;
1211	int devlen;
1212
1213	for (sp = sessions; sp; sp = sp->se_next)
1214		sp->se_flags &= ~SE_PRESENT;
1215
1216	devlen = sizeof(_PATH_DEV) - 1;
1217	while ((typ = getttyent())) {
1218		++session_index;
1219
1220		for (sprev = 0, sp = sessions; sp; sprev = sp, sp = sp->se_next)
1221			if (strcmp(typ->ty_name, sp->se_device + devlen) == 0)
1222				break;
1223
1224		if (sp) {
1225			sp->se_flags |= SE_PRESENT;
1226			if (sp->se_index != session_index) {
1227				warning("port %s changed utmp index from %d to %d",
1228				       sp->se_device, sp->se_index,
1229				       session_index);
1230				sp->se_index = session_index;
1231			}
1232			if ((typ->ty_status & TTY_ON) == 0 ||
1233			    typ->ty_getty == 0) {
1234				sp->se_flags |= SE_SHUTDOWN;
1235				kill(sp->se_process, SIGHUP);
1236				continue;
1237			}
1238			sp->se_flags &= ~SE_SHUTDOWN;
1239			if (setupargv(sp, typ) == 0) {
1240				warning("can't parse getty for port %s",
1241					sp->se_device);
1242				sp->se_flags |= SE_SHUTDOWN;
1243				kill(sp->se_process, SIGHUP);
1244			}
1245			continue;
1246		}
1247
1248		new_session(sprev, session_index, typ);
1249	}
1250
1251	endttyent();
1252
1253	for (sp = sessions; sp; sp = sp->se_next)
1254		if ((sp->se_flags & SE_PRESENT) == 0) {
1255			sp->se_flags |= SE_SHUTDOWN;
1256			kill(sp->se_process, SIGHUP);
1257		}
1258
1259	return (state_func_t) multi_user;
1260}
1261
1262/*
1263 * Block further logins.
1264 */
1265state_func_t
1266catatonia(void)
1267{
1268	session_t *sp;
1269
1270	for (sp = sessions; sp; sp = sp->se_next)
1271		sp->se_flags |= SE_SHUTDOWN;
1272
1273	return (state_func_t) multi_user;
1274}
1275
1276/*
1277 * Note SIGALRM.
1278 */
1279void
1280alrm_handler(int sig)
1281{
1282	clang = 1;
1283}
1284
1285/*
1286 * Bring the system down to single user nicely, after run the shutdown script.
1287 */
1288state_func_t
1289nice_death(void)
1290{
1291	session_t *sp;
1292	int i;
1293	pid_t pid;
1294	static const int death_sigs[3] = { SIGHUP, SIGTERM, SIGKILL };
1295	int howto = RB_HALT;
1296	int status;
1297
1298	for (sp = sessions; sp; sp = sp->se_next) {
1299		sp->se_flags &= ~SE_PRESENT;
1300		sp->se_flags |= SE_SHUTDOWN;
1301		kill(sp->se_process, SIGHUP);
1302	}
1303
1304	/* NB: should send a message to the session logger to avoid blocking. */
1305	logwtmp("~", "shutdown", "");
1306
1307	if (access(_PATH_RUNCOM, R_OK) != -1) {
1308		pid_t pid;
1309		struct sigaction sa;
1310
1311		switch ((pid = fork())) {
1312		case -1:
1313			break;
1314		case 0:
1315
1316			memset(&sa, 0, sizeof sa);
1317			sigemptyset(&sa.sa_mask);
1318			sa.sa_flags = 0;
1319			sa.sa_handler = SIG_IGN;
1320			(void) sigaction(SIGTSTP, &sa, NULL);
1321			(void) sigaction(SIGHUP, &sa, NULL);
1322
1323			setctty(_PATH_CONSOLE);
1324
1325			sigprocmask(SIG_SETMASK, &sa.sa_mask, NULL);
1326
1327			execl(_PATH_BSHELL, "sh", _PATH_RUNCOM, "shutdown",
1328			    (char *)NULL);
1329			stall("can't exec %s for %s %s: %m", _PATH_BSHELL,
1330			    _PATH_RUNCOM, "shutdown");
1331			_exit(1);
1332		default:
1333			waitpid(pid, &status, 0);
1334			if (WIFEXITED(status) && WEXITSTATUS(status) == 2)
1335				howto |= RB_POWERDOWN;
1336		}
1337	}
1338
1339	for (i = 0; i < 3; ++i) {
1340		if (kill(-1, death_sigs[i]) == -1 && errno == ESRCH)
1341			goto die;
1342
1343		clang = 0;
1344		alarm(DEATH_WATCH);
1345		do
1346			if ((pid = waitpid(-1, NULL, 0)) != -1)
1347				collect_child(pid);
1348		while (clang == 0 && errno != ECHILD);
1349
1350		if (errno == ECHILD)
1351			goto die;
1352	}
1353
1354	warning("some processes would not die; ps axl advised");
1355
1356die:
1357	reboot(howto);
1358
1359	/* ... and if that fails.. oh well */
1360	return (state_func_t) single_user;
1361}
1362
1363/*
1364 * Bring the system down to single user.
1365 */
1366state_func_t
1367death(void)
1368{
1369	session_t *sp;
1370	int i;
1371	pid_t pid;
1372	static const int death_sigs[3] = { SIGHUP, SIGTERM, SIGKILL };
1373
1374	for (sp = sessions; sp; sp = sp->se_next)
1375		sp->se_flags |= SE_SHUTDOWN;
1376
1377	/* NB: should send a message to the session logger to avoid blocking. */
1378	logwtmp("~", "shutdown", "");
1379
1380	for (i = 0; i < 3; ++i) {
1381		if (kill(-1, death_sigs[i]) == -1 && errno == ESRCH)
1382			return (state_func_t) single_user;
1383
1384		clang = 0;
1385		alarm(DEATH_WATCH);
1386		do
1387			if ((pid = waitpid(-1, NULL, 0)) != -1)
1388				collect_child(pid);
1389		while (clang == 0 && errno != ECHILD);
1390
1391		if (errno == ECHILD)
1392			return (state_func_t) single_user;
1393	}
1394
1395	warning("some processes would not die; ps axl advised");
1396
1397	return (state_func_t) single_user;
1398}
1399
1400#ifdef LOGIN_CAP
1401void
1402setprocresources(char *class)
1403{
1404	login_cap_t *lc;
1405
1406	if ((lc = login_getclass(class)) != NULL) {
1407		setusercontext(lc, NULL, 0,
1408		    LOGIN_SETPRIORITY|LOGIN_SETRESOURCES|LOGIN_SETUMASK);
1409		login_close(lc);
1410	}
1411}
1412#endif
1413