init.c revision 1.30 
1/*	$OpenBSD: init.c,v 1.30 2002/12/11 21:58:37 millert 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 1.30 2002/12/11 21:58:37 millert 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
866	if ((typ->ty_status & TTY_ON) == 0 ||
867	    typ->ty_name == 0 ||
868	    typ->ty_getty == 0)
869		return (0);
870
871	sp = (session_t *) malloc(sizeof (session_t));
872	memset(sp, 0, sizeof *sp);
873
874	sp->se_flags = SE_PRESENT;
875	sp->se_index = session_index;
876
877	sp->se_device = malloc(sizeof(_PATH_DEV) + strlen(typ->ty_name));
878	(void) sprintf(sp->se_device, "%s%s", _PATH_DEV, typ->ty_name);
879
880	if (setupargv(sp, typ) == 0) {
881		free_session(sp);
882		return (0);
883	}
884
885	sp->se_next = 0;
886	if (sprev == 0) {
887		sessions = sp;
888		sp->se_prev = 0;
889	} else {
890		sprev->se_next = sp;
891		sp->se_prev = sprev;
892	}
893
894	return (sp);
895}
896
897/*
898 * Calculate getty and if useful window argv vectors.
899 */
900int
901setupargv(session_t *sp, struct ttyent *typ)
902{
903
904	if (sp->se_getty) {
905		free(sp->se_getty);
906		free(sp->se_getty_argv);
907	}
908	sp->se_getty = malloc(strlen(typ->ty_getty) + strlen(typ->ty_name) + 2);
909	(void) sprintf(sp->se_getty, "%s %s", typ->ty_getty, typ->ty_name);
910	sp->se_getty_argv = construct_argv(sp->se_getty);
911	if (sp->se_getty_argv == 0) {
912		warning("can't parse getty for port %s", sp->se_device);
913		free(sp->se_getty);
914		sp->se_getty = 0;
915		return (0);
916	}
917	if (typ->ty_window) {
918		if (sp->se_window)
919			free(sp->se_window);
920		sp->se_window = strdup(typ->ty_window);
921		sp->se_window_argv = construct_argv(sp->se_window);
922		if (sp->se_window_argv == 0) {
923			warning("can't parse window for port %s",
924				sp->se_device);
925			free(sp->se_window);
926			sp->se_window = 0;
927			return (0);
928		}
929	}
930	return (1);
931}
932
933/*
934 * Walk the list of ttys and create sessions for each active line.
935 */
936state_func_t
937read_ttys(void)
938{
939	int session_index = 0;
940	session_t *sp, *snext;
941	struct ttyent *typ;
942
943	/*
944	 * Destroy any previous session state.
945	 * There shouldn't be any, but just in case...
946	 */
947	for (sp = sessions; sp; sp = snext) {
948		if (sp->se_process)
949			clear_session_logs(sp);
950		snext = sp->se_next;
951		free_session(sp);
952	}
953	sessions = 0;
954	if (start_session_db())
955		return (state_func_t) single_user;
956
957	/*
958	 * Allocate a session entry for each active port.
959	 * Note that sp starts at 0.
960	 */
961	while ((typ = getttyent()))
962		if ((snext = new_session(sp, ++session_index, typ)))
963			sp = snext;
964
965	endttyent();
966
967	return (state_func_t) multi_user;
968}
969
970/*
971 * Start a window system running.
972 */
973void
974start_window_system(session_t *sp)
975{
976	pid_t pid;
977	sigset_t mask;
978
979	if ((pid = fork()) == -1) {
980		emergency("can't fork for window system on port %s: %m",
981			sp->se_device);
982		/* hope that getty fails and we can try again */
983		return;
984	}
985
986	if (pid)
987		return;
988
989	sigemptyset(&mask);
990	sigprocmask(SIG_SETMASK, &mask, NULL);
991
992	if (setsid() < 0)
993		emergency("setsid failed (window) %m");
994
995	setprocresources(RESOURCE_WINDOW);
996
997	execv(sp->se_window_argv[0], sp->se_window_argv);
998	stall("can't exec window system '%s' for port %s: %m",
999		sp->se_window_argv[0], sp->se_device);
1000	_exit(1);
1001}
1002
1003/*
1004 * Start a login session running.
1005 * For first open, man-handle tty directly to determine if it
1006 * really exists. It is not efficient to spawn gettys on devices
1007 * that do not exist.
1008 */
1009pid_t
1010start_getty(session_t *sp)
1011{
1012	pid_t pid;
1013	sigset_t mask;
1014	time_t current_time = time(NULL);
1015	int p[2], new = 1;
1016
1017	if (sp->se_flags & SE_DEVEXISTS)
1018		new = 0;
1019
1020	if (new) {
1021		if (pipe(p) == -1)
1022			return (-1);
1023	}
1024
1025	/*
1026	 * fork(), not vfork() -- we can't afford to block.
1027	 */
1028	if ((pid = fork()) == -1) {
1029		emergency("can't fork for getty on port %s: %m", sp->se_device);
1030		return (-1);
1031	}
1032
1033	if (pid) {
1034		if (new) {
1035			char c;
1036
1037			close(p[1]);
1038			if (read(p[0], &c, 1) != 1) {
1039				close(p[0]);
1040				return (-1);
1041			}
1042			close(p[0]);
1043			if (c == '1')
1044				sp->se_flags |= SE_DEVEXISTS;
1045			else
1046				sp->se_flags |= SE_SHUTDOWN;
1047		}
1048		return (pid);
1049	}
1050	if (new) {
1051		int fd;
1052
1053		close(p[0]);
1054		fd = open(sp->se_device, O_RDONLY | O_NONBLOCK, 0666);
1055		if (fd == -1 && (errno == ENXIO || errno == ENOENT ||
1056		    errno == EISDIR)) {
1057			(void)write(p[1], "0", 1);
1058			close(p[1]);
1059			_exit(1);
1060		}
1061		(void)write(p[1], "1", 1);
1062		close(p[1]);
1063		close(fd);
1064		sleep(1);
1065	}
1066
1067	if (current_time > sp->se_started &&
1068	    current_time - sp->se_started < GETTY_SPACING) {
1069		warning("getty repeating too quickly on port %s, sleeping",
1070		        sp->se_device);
1071		sleep((unsigned) GETTY_SLEEP);
1072	}
1073
1074	if (sp->se_window) {
1075		start_window_system(sp);
1076		sleep(WINDOW_WAIT);
1077	}
1078
1079	sigemptyset(&mask);
1080	sigprocmask(SIG_SETMASK, &mask, NULL);
1081
1082	setprocresources(RESOURCE_GETTY);
1083
1084	execv(sp->se_getty_argv[0], sp->se_getty_argv);
1085	stall("can't exec getty '%s' for port %s: %m",
1086		sp->se_getty_argv[0], sp->se_device);
1087	_exit(1);
1088}
1089
1090/*
1091 * Collect exit status for a child.
1092 * If an exiting login, start a new login running.
1093 */
1094void
1095collect_child(pid_t pid)
1096{
1097	session_t *sp, *sprev, *snext;
1098
1099	if (sessions == NULL)
1100		return;
1101
1102	if ((sp = find_session(pid)) == NULL)
1103		return;
1104
1105	clear_session_logs(sp);
1106	login_fbtab(sp->se_device + sizeof(_PATH_DEV) - 1, 0, 0);
1107	del_session(sp);
1108	sp->se_process = 0;
1109
1110	if (sp->se_flags & SE_SHUTDOWN) {
1111		if ((sprev = sp->se_prev))
1112			sprev->se_next = sp->se_next;
1113		else
1114			sessions = sp->se_next;
1115		if ((snext = sp->se_next))
1116			snext->se_prev = sp->se_prev;
1117		free_session(sp);
1118		return;
1119	}
1120
1121	if ((pid = start_getty(sp)) == -1) {
1122		/* serious trouble */
1123		requested_transition = clean_ttys;
1124		return;
1125	}
1126
1127	sp->se_process = pid;
1128	sp->se_started = time(NULL);
1129	add_session(sp);
1130}
1131
1132/*
1133 * Catch a signal and request a state transition.
1134 */
1135void
1136transition_handler(int sig)
1137{
1138
1139	switch (sig) {
1140	case SIGHUP:
1141		requested_transition = clean_ttys;
1142		break;
1143	case SIGTERM:
1144		requested_transition = death;
1145		break;
1146	case SIGUSR1:
1147		requested_transition = nice_death;
1148		break;
1149	case SIGTSTP:
1150		requested_transition = catatonia;
1151		break;
1152	default:
1153		requested_transition = 0;
1154		break;
1155	}
1156}
1157
1158/*
1159 * Take the system multiuser.
1160 */
1161state_func_t
1162multi_user(void)
1163{
1164	pid_t pid;
1165	session_t *sp;
1166
1167	requested_transition = 0;
1168
1169	/*
1170	 * If the administrator has not set the security level to -1
1171	 * to indicate that the kernel should not run multiuser in secure
1172	 * mode, and the run script has not set a higher level of security
1173	 * than level 1, then put the kernel into secure mode.
1174	 */
1175	if (getsecuritylevel() == 0)
1176		setsecuritylevel(1);
1177
1178	for (sp = sessions; sp; sp = sp->se_next) {
1179		if (sp->se_process)
1180			continue;
1181		if ((pid = start_getty(sp)) == -1) {
1182			/* serious trouble */
1183			requested_transition = clean_ttys;
1184			break;
1185		}
1186		sp->se_process = pid;
1187		sp->se_started = time(NULL);
1188		add_session(sp);
1189	}
1190
1191	while (!requested_transition)
1192		if ((pid = waitpid(-1, NULL, 0)) != -1)
1193			collect_child(pid);
1194
1195	return (state_func_t) requested_transition;
1196}
1197
1198/*
1199 * This is an n-squared algorithm.  We hope it isn't run often...
1200 */
1201state_func_t
1202clean_ttys(void)
1203{
1204	session_t *sp, *sprev;
1205	struct ttyent *typ;
1206	int session_index = 0;
1207	int devlen;
1208
1209	for (sp = sessions; sp; sp = sp->se_next)
1210		sp->se_flags &= ~SE_PRESENT;
1211
1212	devlen = sizeof(_PATH_DEV) - 1;
1213	while ((typ = getttyent())) {
1214		++session_index;
1215
1216		for (sprev = 0, sp = sessions; sp; sprev = sp, sp = sp->se_next)
1217			if (strcmp(typ->ty_name, sp->se_device + devlen) == 0)
1218				break;
1219
1220		if (sp) {
1221			sp->se_flags |= SE_PRESENT;
1222			if (sp->se_index != session_index) {
1223				warning("port %s changed utmp index from %d to %d",
1224				       sp->se_device, sp->se_index,
1225				       session_index);
1226				sp->se_index = session_index;
1227			}
1228			if ((typ->ty_status & TTY_ON) == 0 ||
1229			    typ->ty_getty == 0) {
1230				sp->se_flags |= SE_SHUTDOWN;
1231				kill(sp->se_process, SIGHUP);
1232				continue;
1233			}
1234			sp->se_flags &= ~SE_SHUTDOWN;
1235			if (setupargv(sp, typ) == 0) {
1236				warning("can't parse getty for port %s",
1237					sp->se_device);
1238				sp->se_flags |= SE_SHUTDOWN;
1239				kill(sp->se_process, SIGHUP);
1240			}
1241			continue;
1242		}
1243
1244		new_session(sprev, session_index, typ);
1245	}
1246
1247	endttyent();
1248
1249	for (sp = sessions; sp; sp = sp->se_next)
1250		if ((sp->se_flags & SE_PRESENT) == 0) {
1251			sp->se_flags |= SE_SHUTDOWN;
1252			kill(sp->se_process, SIGHUP);
1253		}
1254
1255	return (state_func_t) multi_user;
1256}
1257
1258/*
1259 * Block further logins.
1260 */
1261state_func_t
1262catatonia(void)
1263{
1264	session_t *sp;
1265
1266	for (sp = sessions; sp; sp = sp->se_next)
1267		sp->se_flags |= SE_SHUTDOWN;
1268
1269	return (state_func_t) multi_user;
1270}
1271
1272/*
1273 * Note SIGALRM.
1274 */
1275void
1276alrm_handler(int sig)
1277{
1278	clang = 1;
1279}
1280
1281/*
1282 * Bring the system down to single user nicely, after run the shutdown script.
1283 */
1284state_func_t
1285nice_death(void)
1286{
1287	session_t *sp;
1288	int i;
1289	pid_t pid;
1290	static const int death_sigs[3] = { SIGHUP, SIGTERM, SIGKILL };
1291	int howto = RB_HALT;
1292	int status;
1293
1294	for (sp = sessions; sp; sp = sp->se_next) {
1295		sp->se_flags &= ~SE_PRESENT;
1296		sp->se_flags |= SE_SHUTDOWN;
1297		kill(sp->se_process, SIGHUP);
1298	}
1299
1300	/* NB: should send a message to the session logger to avoid blocking. */
1301	logwtmp("~", "shutdown", "");
1302
1303	if (access(_PATH_RUNCOM, R_OK) != -1) {
1304		pid_t pid;
1305		struct sigaction sa;
1306
1307		switch ((pid = fork())) {
1308		case -1:
1309			break;
1310		case 0:
1311
1312			memset(&sa, 0, sizeof sa);
1313			sigemptyset(&sa.sa_mask);
1314			sa.sa_flags = 0;
1315			sa.sa_handler = SIG_IGN;
1316			(void) sigaction(SIGTSTP, &sa, NULL);
1317			(void) sigaction(SIGHUP, &sa, NULL);
1318
1319			setctty(_PATH_CONSOLE);
1320
1321			sigprocmask(SIG_SETMASK, &sa.sa_mask, NULL);
1322
1323			execl(_PATH_BSHELL, "sh", _PATH_RUNCOM, "shutdown",
1324			    (char *)NULL);
1325			stall("can't exec %s for %s %s: %m", _PATH_BSHELL,
1326			    _PATH_RUNCOM, "shutdown");
1327			_exit(1);
1328		default:
1329			waitpid(pid, &status, 0);
1330			if (WIFEXITED(status) && WEXITSTATUS(status) == 2)
1331				howto |= RB_POWERDOWN;
1332		}
1333	}
1334
1335	for (i = 0; i < 3; ++i) {
1336		if (kill(-1, death_sigs[i]) == -1 && errno == ESRCH)
1337			goto die;
1338
1339		clang = 0;
1340		alarm(DEATH_WATCH);
1341		do
1342			if ((pid = waitpid(-1, NULL, 0)) != -1)
1343				collect_child(pid);
1344		while (clang == 0 && errno != ECHILD);
1345
1346		if (errno == ECHILD)
1347			goto die;
1348	}
1349
1350	warning("some processes would not die; ps axl advised");
1351
1352die:
1353	reboot(howto);
1354
1355	/* ... and if that fails.. oh well */
1356	return (state_func_t) single_user;
1357}
1358
1359/*
1360 * Bring the system down to single user.
1361 */
1362state_func_t
1363death(void)
1364{
1365	session_t *sp;
1366	int i;
1367	pid_t pid;
1368	static const int death_sigs[3] = { SIGHUP, SIGTERM, SIGKILL };
1369
1370	for (sp = sessions; sp; sp = sp->se_next)
1371		sp->se_flags |= SE_SHUTDOWN;
1372
1373	/* NB: should send a message to the session logger to avoid blocking. */
1374	logwtmp("~", "shutdown", "");
1375
1376	for (i = 0; i < 3; ++i) {
1377		if (kill(-1, death_sigs[i]) == -1 && errno == ESRCH)
1378			return (state_func_t) single_user;
1379
1380		clang = 0;
1381		alarm(DEATH_WATCH);
1382		do
1383			if ((pid = waitpid(-1, NULL, 0)) != -1)
1384				collect_child(pid);
1385		while (clang == 0 && errno != ECHILD);
1386
1387		if (errno == ECHILD)
1388			return (state_func_t) single_user;
1389	}
1390
1391	warning("some processes would not die; ps axl advised");
1392
1393	return (state_func_t) single_user;
1394}
1395
1396#ifdef LOGIN_CAP
1397void
1398setprocresources(char *class)
1399{
1400	login_cap_t *lc;
1401
1402	if ((lc = login_getclass(class)) != NULL) {
1403		setusercontext(lc, NULL, 0,
1404		    LOGIN_SETPRIORITY|LOGIN_SETRESOURCES|LOGIN_SETUMASK);
1405		login_close(lc);
1406	}
1407}
1408#endif
1409