init.c revision 1.35 
1/*	$OpenBSD: init.c,v 1.35 2004/03/16 01:11:09 tedu 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#ifndef lint
37static char copyright[] =
38"@(#) Copyright (c) 1991, 1993\n\
39	The Regents of the University of California.  All rights reserved.\n";
40#endif /* not lint */
41
42#ifndef lint
43#if 0
44static char sccsid[] = "@(#)init.c	8.2 (Berkeley) 4/28/95";
45#else
46static char rcsid[] = "$OpenBSD: init.c,v 1.35 2004/03/16 01:11:09 tedu Exp $";
47#endif
48#endif /* not lint */
49
50#include <sys/param.h>
51#include <sys/sysctl.h>
52#include <sys/wait.h>
53#include <sys/reboot.h>
54
55#include <db.h>
56#include <errno.h>
57#include <fcntl.h>
58#include <signal.h>
59#include <stdarg.h>
60#include <stdio.h>
61#include <stdlib.h>
62#include <string.h>
63#include <syslog.h>
64#include <time.h>
65#include <ttyent.h>
66#include <unistd.h>
67#include <util.h>
68
69#ifdef SECURE
70#include <pwd.h>
71#endif
72
73#ifdef LOGIN_CAP
74#include <login_cap.h>
75#endif
76
77#include "pathnames.h"
78
79/*
80 * Sleep times; used to prevent thrashing.
81 */
82#define	GETTY_SPACING		 5	/* N secs minimum getty spacing */
83#define	GETTY_SLEEP		30	/* sleep N secs after spacing problem */
84#define	WINDOW_WAIT		 3	/* wait N secs after starting window */
85#define	STALL_TIMEOUT		30	/* wait N secs after warning */
86#define	DEATH_WATCH		10	/* wait N secs for procs to die */
87
88/*
89 * User-based resource limits.
90 */
91#define RESOURCE_RC		"daemon"
92#define RESOURCE_WINDOW		"default"
93#define RESOURCE_GETTY		"default"
94
95#ifndef DEFAULT_STATE
96#define DEFAULT_STATE		runcom
97#endif
98
99void handle(sig_t, ...);
100void delset(sigset_t *, ...);
101
102void stall(char *, ...);
103void warning(char *, ...);
104void emergency(char *, ...);
105void disaster(int);
106void badsys(int);
107
108/*
109 * We really need a recursive typedef...
110 * The following at least guarantees that the return type of (*state_t)()
111 * is sufficiently wide to hold a function pointer.
112 */
113typedef long (*state_func_t)(void);
114typedef state_func_t (*state_t)(void);
115
116state_func_t single_user(void);
117state_func_t runcom(void);
118state_func_t read_ttys(void);
119state_func_t multi_user(void);
120state_func_t clean_ttys(void);
121state_func_t catatonia(void);
122state_func_t death(void);
123state_func_t nice_death(void);
124
125enum { AUTOBOOT, FASTBOOT } runcom_mode = AUTOBOOT;
126
127void transition(state_t);
128state_t requested_transition = DEFAULT_STATE;
129
130void setctty(char *);
131
132typedef struct init_session {
133	int	se_index;		/* index of entry in ttys file */
134	pid_t	se_process;		/* controlling process */
135	time_t	se_started;		/* used to avoid thrashing */
136	int	se_flags;		/* status of session */
137#define	SE_SHUTDOWN	0x1		/* session won't be restarted */
138#define	SE_PRESENT	0x2		/* session is in /etc/ttys */
139#define	SE_DEVEXISTS	0x4		/* open does not result in ENODEV */
140	char	*se_device;		/* filename of port */
141	char	*se_getty;		/* what to run on that port */
142	char	**se_getty_argv;	/* pre-parsed argument array */
143	char	*se_window;		/* window system (started only once) */
144	char	**se_window_argv;	/* pre-parsed argument array */
145	struct	init_session *se_prev;
146	struct	init_session *se_next;
147} session_t;
148
149void free_session(session_t *);
150session_t *new_session(session_t *, int, struct ttyent *);
151session_t *sessions;
152
153char **construct_argv(char *);
154void start_window_system(session_t *);
155void collect_child(pid_t);
156pid_t start_getty(session_t *);
157void transition_handler(int);
158void alrm_handler(int);
159void setsecuritylevel(int);
160int getsecuritylevel(void);
161int setupargv(session_t *, struct ttyent *);
162int clang;
163
164#ifdef LOGIN_CAP
165void setprocresources(char *);
166#else
167#define setprocresources(p)
168#endif
169
170void clear_session_logs(session_t *);
171
172int start_session_db(void);
173void add_session(session_t *);
174void del_session(session_t *);
175session_t *find_session(pid_t);
176DB *session_db;
177
178/*
179 * The mother of all processes.
180 */
181int
182main(int argc, char *argv[])
183{
184	int c;
185	struct sigaction sa;
186	sigset_t mask;
187
188	/* Dispose of random users. */
189	if (getuid() != 0) {
190		(void)fprintf(stderr, "init: %s\n", strerror(EPERM));
191		exit (1);
192	}
193
194	/* System V users like to reexec init. */
195	if (getpid() != 1) {
196		(void)fprintf(stderr, "init: already running\n");
197		exit (1);
198	}
199
200	/*
201	 * Note that this does NOT open a file...
202	 * Does 'init' deserve its own facility number?
203	 */
204	openlog("init", LOG_CONS|LOG_ODELAY, LOG_AUTH);
205
206	/*
207	 * Create an initial session.
208	 */
209	if (setsid() < 0)
210		warning("initial setsid() failed: %m");
211
212	/*
213	 * Establish an initial user so that programs running
214	 * single user do not freak out and die (like passwd).
215	 */
216	if (setlogin("root") < 0)
217		warning("setlogin() failed: %m");
218
219	/*
220	 * This code assumes that we always get arguments through flags,
221	 * never through bits set in some random machine register.
222	 */
223	while ((c = getopt(argc, argv, "sf")) != -1)
224		switch (c) {
225		case 's':
226			requested_transition = single_user;
227			break;
228		case 'f':
229			runcom_mode = FASTBOOT;
230			break;
231		default:
232			warning("unrecognized flag '-%c'", c);
233			break;
234		}
235
236	if (optind != argc)
237		warning("ignoring excess arguments");
238
239	/*
240	 * We catch or block signals rather than ignore them,
241	 * so that they get reset on exec.
242	 */
243	handle(badsys, SIGSYS, 0);
244	handle(disaster, SIGABRT, SIGFPE, SIGILL, SIGSEGV,
245	    SIGBUS, SIGXCPU, SIGXFSZ, 0);
246	handle(transition_handler, SIGHUP, SIGTERM, SIGTSTP, SIGUSR1, 0);
247	handle(alrm_handler, SIGALRM, 0);
248	sigfillset(&mask);
249	delset(&mask, SIGABRT, SIGFPE, SIGILL, SIGSEGV, SIGBUS, SIGSYS,
250	    SIGXCPU, SIGXFSZ, SIGHUP, SIGTERM, SIGUSR1, SIGTSTP, SIGALRM, 0);
251	sigprocmask(SIG_SETMASK, &mask, NULL);
252	memset(&sa, 0, sizeof sa);
253	sigemptyset(&sa.sa_mask);
254	sa.sa_flags = 0;
255	sa.sa_handler = SIG_IGN;
256	(void) sigaction(SIGTTIN, &sa, NULL);
257	(void) sigaction(SIGTTOU, &sa, NULL);
258
259	/*
260	 * Paranoia.
261	 */
262	close(STDIN_FILENO);
263	close(STDOUT_FILENO);
264	close(STDERR_FILENO);
265
266	/*
267	 * Start the state machine.
268	 */
269	transition(requested_transition);
270
271	/*
272	 * Should never reach here.
273	 */
274	exit(1);
275}
276
277/*
278 * Associate a function with a signal handler.
279 */
280void
281handle(sig_t handler, ...)
282{
283	int sig;
284	struct sigaction sa;
285	sigset_t mask_everything;
286	va_list ap;
287
288	va_start(ap, handler);
289
290	memset(&sa, 0, sizeof sa);
291	sa.sa_handler = handler;
292	sigfillset(&mask_everything);
293
294	while ((sig = va_arg(ap, int))) {
295		sa.sa_mask = mask_everything;
296		/* XXX SA_RESTART? */
297		sa.sa_flags = sig == SIGCHLD ? SA_NOCLDSTOP : 0;
298		sigaction(sig, &sa, NULL);
299	}
300	va_end(ap);
301}
302
303/*
304 * Delete a set of signals from a mask.
305 */
306void
307delset(sigset_t *maskp, ...)
308{
309	int sig;
310	va_list ap;
311
312	va_start(ap, maskp);
313	while ((sig = va_arg(ap, int)))
314		sigdelset(maskp, sig);
315	va_end(ap);
316}
317
318/*
319 * Log a message and sleep for a while (to give someone an opportunity
320 * to read it and to save log or hardcopy output if the problem is chronic).
321 * NB: should send a message to the session logger to avoid blocking.
322 */
323void
324stall(char *message, ...)
325{
326	va_list ap;
327
328	va_start(ap, message);
329	vsyslog(LOG_ALERT, message, ap);
330	va_end(ap);
331	closelog();
332	sleep(STALL_TIMEOUT);
333}
334
335/*
336 * Like stall(), but doesn't sleep.
337 * If cpp had variadic macros, the two functions could be #defines for another.
338 * NB: should send a message to the session logger to avoid blocking.
339 */
340void
341warning(char *message, ...)
342{
343	va_list ap;
344
345	va_start(ap, message);
346	vsyslog(LOG_ALERT, message, ap);
347	va_end(ap);
348	closelog();
349}
350
351/*
352 * Log an emergency message.
353 * NB: should send a message to the session logger to avoid blocking.
354 */
355void
356emergency(char *message, ...)
357{
358	struct syslog_data sdata = SYSLOG_DATA_INIT;
359	va_list ap;
360
361	va_start(ap, message);
362	vsyslog_r(LOG_EMERG, &sdata, message, ap);
363	va_end(ap);
364}
365
366/*
367 * Catch a SIGSYS signal.
368 *
369 * These may arise if a system does not support sysctl.
370 * We tolerate up to 25 of these, then throw in the towel.
371 */
372void
373badsys(int sig)
374{
375	static int badcount = 0;
376
377	if (badcount++ < 25)
378		return;
379	disaster(sig);
380}
381
382/*
383 * Catch an unexpected signal.
384 */
385void
386disaster(int sig)
387{
388	emergency("fatal signal: %s", strsignal(sig));
389
390	sleep(STALL_TIMEOUT);
391	_exit(sig);		/* reboot */
392}
393
394/*
395 * Get the security level of the kernel.
396 */
397int
398getsecuritylevel(void)
399{
400#ifdef KERN_SECURELVL
401	int name[2], curlevel;
402	size_t len;
403
404	name[0] = CTL_KERN;
405	name[1] = KERN_SECURELVL;
406	len = sizeof curlevel;
407	if (sysctl(name, 2, &curlevel, &len, NULL, 0) == -1) {
408		emergency("cannot get kernel security level: %s",
409		    strerror(errno));
410		return (-1);
411	}
412	return (curlevel);
413#else
414	return (-1);
415#endif
416}
417
418/*
419 * Set the security level of the kernel.
420 */
421void
422setsecuritylevel(int newlevel)
423{
424#ifdef KERN_SECURELVL
425	int name[2], curlevel;
426
427	curlevel = getsecuritylevel();
428	if (newlevel == curlevel)
429		return;
430	name[0] = CTL_KERN;
431	name[1] = KERN_SECURELVL;
432	if (sysctl(name, 2, NULL, NULL, &newlevel, sizeof newlevel) == -1) {
433		emergency(
434		    "cannot change kernel security level from %d to %d: %s",
435		    curlevel, newlevel, strerror(errno));
436		return;
437	}
438#ifdef SECURE
439	warning("kernel security level changed from %d to %d",
440	    curlevel, newlevel);
441#endif
442#endif
443}
444
445/*
446 * Change states in the finite state machine.
447 * The initial state is passed as an argument.
448 */
449void
450transition(state_t s)
451{
452	for (;;)
453		s = (state_t) (*s)();
454}
455
456/*
457 * Close out the accounting files for a login session.
458 * NB: should send a message to the session logger to avoid blocking.
459 */
460void
461clear_session_logs(session_t *sp)
462{
463	char *line = sp->se_device + sizeof(_PATH_DEV) - 1;
464
465	if (logout(line))
466		logwtmp(line, "", "");
467}
468
469/*
470 * Start a session and allocate a controlling terminal.
471 * Only called by children of init after forking.
472 */
473void
474setctty(char *name)
475{
476	int fd;
477
478	(void) revoke(name);
479	sleep(2);			/* leave DTR low */
480	if ((fd = open(name, O_RDWR)) == -1) {
481		stall("can't open %s: %m", name);
482		_exit(1);
483	}
484	if (login_tty(fd) == -1) {
485		stall("can't get %s for controlling terminal: %m", name);
486		_exit(1);
487	}
488}
489
490/*
491 * Bring the system up single user.
492 */
493state_func_t
494single_user(void)
495{
496	pid_t pid, wpid;
497	int status;
498	sigset_t mask;
499	char shell[MAXPATHLEN];		/* Allocate space here */
500	char name[MAXPATHLEN];		/* Name (argv[0]) of shell */
501	char *argv[2];
502#ifdef SECURE
503	struct ttyent *typ;
504	struct passwd *pp;
505	static const char banner[] =
506		"Enter root password, or ^D to go multi-user\n";
507	char *clear, *password;
508#endif
509
510	/* Init shell and name */
511	strlcpy(shell, _PATH_BSHELL, sizeof shell);
512	strlcpy(name, "-sh", sizeof name);
513
514	/*
515	 * If the kernel is in secure mode, downgrade it to insecure mode.
516	 */
517	if (getsecuritylevel() > 0)
518		setsecuritylevel(0);
519
520	if ((pid = fork()) == 0) {
521		/*
522		 * Start the single user session.
523		 */
524		setctty(_PATH_CONSOLE);
525
526#ifdef SECURE
527		/*
528		 * Check the root password.
529		 * We don't care if the console is 'on' by default;
530		 * it's the only tty that can be 'off' and 'secure'.
531		 */
532		typ = getttynam("console");
533		pp = getpwnam("root");
534		if (typ && (typ->ty_status & TTY_SECURE) == 0 && pp &&
535		    *pp->pw_passwd) {
536			write(STDERR_FILENO, banner, sizeof banner - 1);
537			for (;;) {
538				clear = getpass("Password:");
539				if (clear == 0 || *clear == '\0')
540					_exit(0);
541				password = crypt(clear, pp->pw_passwd);
542				memset(clear, 0, _PASSWORD_LEN);
543				if (strcmp(password, pp->pw_passwd) == 0)
544					break;
545				warning("single-user login failed\n");
546			}
547		}
548		endttyent();
549		endpwent();
550#endif /* SECURE */
551
552#ifdef DEBUGSHELL
553		{
554			char altshell[128], *cp = altshell;
555			int num;
556
557#define	SHREQUEST \
558	"Enter pathname of shell or RETURN for sh: "
559
560			(void)write(STDERR_FILENO,
561			    SHREQUEST, sizeof(SHREQUEST) - 1);
562			while ((num = read(STDIN_FILENO, cp, 1)) != -1 &&
563			    num != 0 && *cp != '\n' && cp < &altshell[127])
564				cp++;
565			*cp = '\0';
566
567			/* Copy in alternate shell */
568			if (altshell[0] != '\0'){
569				char *p;
570
571				/* Binary to exec */
572				strlcpy(shell, altshell, sizeof shell);
573
574				/* argv[0] */
575				p = strrchr(altshell, '/');
576				if(p == NULL) p = altshell;
577				else p++;
578
579				name[0] = '-';
580				strlcpy(&name[1], p, sizeof name -1);
581			}
582		}
583#endif /* DEBUGSHELL */
584
585		/*
586		 * Unblock signals.
587		 * We catch all the interesting ones,
588		 * and those are reset to SIG_DFL on exec.
589		 */
590		sigemptyset(&mask);
591		sigprocmask(SIG_SETMASK, &mask, NULL);
592
593		/*
594		 * Fire off a shell.
595		 * If the default one doesn't work, try the Bourne shell.
596		 */
597		argv[0] = name;
598		argv[1] = NULL;
599		setenv("PATH", _PATH_STDPATH, 1);
600		execv(shell, argv);
601		emergency("can't exec %s for single user: %m", shell);
602
603		argv[0] = "-sh";
604		argv[1] = NULL;
605		execv(_PATH_BSHELL, argv);
606		emergency("can't exec %s for single user: %m", _PATH_BSHELL);
607		sleep(STALL_TIMEOUT);
608		_exit(1);
609	}
610
611	if (pid == -1) {
612		/*
613		 * We are seriously hosed.  Do our best.
614		 */
615		emergency("can't fork single-user shell, trying again");
616		while (waitpid(-1, NULL, WNOHANG) > 0)
617			continue;
618		return (state_func_t) single_user;
619	}
620
621	requested_transition = 0;
622	do {
623		if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1)
624			collect_child(wpid);
625		if (wpid == -1) {
626			if (errno == EINTR)
627				continue;
628			warning("wait for single-user shell failed: %m; restarting");
629			return (state_func_t) single_user;
630		}
631		if (wpid == pid && WIFSTOPPED(status)) {
632			warning("init: shell stopped, restarting\n");
633			kill(pid, SIGCONT);
634			wpid = -1;
635		}
636	} while (wpid != pid && !requested_transition);
637
638	if (requested_transition)
639		return (state_func_t) requested_transition;
640
641	if (!WIFEXITED(status)) {
642		if (WTERMSIG(status) == SIGKILL) {
643			/*
644			 *  reboot(8) killed shell?
645			 */
646			warning("single user shell terminated.");
647			sleep(STALL_TIMEOUT);
648			_exit(0);
649		} else {
650			warning("single user shell terminated, restarting");
651			return (state_func_t) single_user;
652		}
653	}
654
655	runcom_mode = FASTBOOT;
656	return (state_func_t) runcom;
657}
658
659/*
660 * Run the system startup script.
661 */
662state_func_t
663runcom(void)
664{
665	pid_t pid, wpid;
666	int status;
667	char *argv[4];
668	struct sigaction sa;
669
670	if ((pid = fork()) == 0) {
671		memset(&sa, 0, sizeof sa);
672		sigemptyset(&sa.sa_mask);
673		sa.sa_flags = 0;
674		sa.sa_handler = SIG_IGN;
675		(void) sigaction(SIGTSTP, &sa, NULL);
676		(void) sigaction(SIGHUP, &sa, NULL);
677
678		setctty(_PATH_CONSOLE);
679
680		argv[0] = "sh";
681		argv[1] = _PATH_RUNCOM;
682		argv[2] = runcom_mode == AUTOBOOT ? "autoboot" : 0;
683		argv[3] = 0;
684
685		sigprocmask(SIG_SETMASK, &sa.sa_mask, NULL);
686
687		setprocresources(RESOURCE_RC);
688
689		execv(_PATH_BSHELL, argv);
690		stall("can't exec %s for %s: %m", _PATH_BSHELL, _PATH_RUNCOM);
691		_exit(1);	/* force single user mode */
692	}
693
694	if (pid == -1) {
695		emergency("can't fork for %s on %s: %m",
696			_PATH_BSHELL, _PATH_RUNCOM);
697		while (waitpid(-1, NULL, WNOHANG) > 0)
698			continue;
699		sleep(STALL_TIMEOUT);
700		return (state_func_t) single_user;
701	}
702
703	/*
704	 * Copied from single_user().  This is a bit paranoid.
705	 */
706	do {
707		if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1)
708			collect_child(wpid);
709		if (wpid == -1) {
710			if (errno == EINTR)
711				continue;
712			warning("wait for %s on %s failed: %m; going to single user mode",
713			    _PATH_BSHELL, _PATH_RUNCOM);
714			return (state_func_t) single_user;
715		}
716		if (wpid == pid && WIFSTOPPED(status)) {
717			warning("init: %s on %s stopped, restarting\n",
718			    _PATH_BSHELL, _PATH_RUNCOM);
719			kill(pid, SIGCONT);
720			wpid = -1;
721		}
722	} while (wpid != pid);
723
724	if (WIFSIGNALED(status) && WTERMSIG(status) == SIGTERM &&
725	    requested_transition == catatonia) {
726		/* /etc/rc executed /sbin/reboot; wait for the end quietly */
727		sigset_t s;
728
729		sigfillset(&s);
730		for (;;)
731			sigsuspend(&s);
732	}
733
734	if (!WIFEXITED(status)) {
735		warning("%s on %s terminated abnormally, going to single user mode",
736		    _PATH_BSHELL, _PATH_RUNCOM);
737		return (state_func_t) single_user;
738	}
739
740	if (WEXITSTATUS(status))
741		return (state_func_t) single_user;
742
743	runcom_mode = AUTOBOOT;		/* the default */
744	/* NB: should send a message to the session logger to avoid blocking. */
745	logwtmp("~", "reboot", "");
746	return (state_func_t) read_ttys;
747}
748
749/*
750 * Open the session database.
751 *
752 * NB: We could pass in the size here; is it necessary?
753 */
754int
755start_session_db(void)
756{
757	if (session_db && (*session_db->close)(session_db))
758		emergency("session database close: %s", strerror(errno));
759	if ((session_db = dbopen(NULL, O_RDWR, 0, DB_HASH, NULL)) == 0) {
760		emergency("session database open: %s", strerror(errno));
761		return (1);
762	}
763	return (0);
764}
765
766/*
767 * Add a new login session.
768 */
769void
770add_session(session_t *sp)
771{
772	DBT key;
773	DBT data;
774
775	key.data = &sp->se_process;
776	key.size = sizeof sp->se_process;
777	data.data = &sp;
778	data.size = sizeof sp;
779
780	if ((*session_db->put)(session_db, &key, &data, 0))
781		emergency("insert %d: %s", sp->se_process, strerror(errno));
782}
783
784/*
785 * Delete an old login session.
786 */
787void
788del_session(session_t *sp)
789{
790	DBT key;
791
792	key.data = &sp->se_process;
793	key.size = sizeof sp->se_process;
794
795	if ((*session_db->del)(session_db, &key, 0))
796		emergency("delete %d: %s", sp->se_process, strerror(errno));
797}
798
799/*
800 * Look up a login session by pid.
801 */
802session_t *
803find_session(pid_t pid)
804{
805	DBT key;
806	DBT data;
807	session_t *ret;
808
809	key.data = &pid;
810	key.size = sizeof pid;
811	if ((*session_db->get)(session_db, &key, &data, 0) != 0)
812		return (0);
813	memcpy(&ret, data.data, sizeof(ret));
814	return (ret);
815}
816
817/*
818 * Construct an argument vector from a command line.
819 */
820char **
821construct_argv(char *command)
822{
823	int argc = 0;
824	char **argv = (char **) malloc(((strlen(command) + 1) / 2 + 1) *
825	    sizeof (char *));
826	static const char separators[] = " \t";
827
828	if ((argv[argc++] = strtok(command, separators)) == 0)
829		return (0);
830	while ((argv[argc++] = strtok(NULL, separators)))
831		continue;
832	return (argv);
833}
834
835/*
836 * Deallocate a session descriptor.
837 */
838void
839free_session(session_t *sp)
840{
841	free(sp->se_device);
842	if (sp->se_getty) {
843		free(sp->se_getty);
844		free(sp->se_getty_argv);
845	}
846	if (sp->se_window) {
847		free(sp->se_window);
848		free(sp->se_window_argv);
849	}
850	free(sp);
851}
852
853/*
854 * Allocate a new session descriptor.
855 */
856session_t *
857new_session(session_t *sprev, int session_index, struct ttyent *typ)
858{
859	session_t *sp;
860	size_t len;
861
862	if ((typ->ty_status & TTY_ON) == 0 ||
863	    typ->ty_name == 0 ||
864	    typ->ty_getty == 0)
865		return (0);
866
867	sp = (session_t *) malloc(sizeof (session_t));
868	memset(sp, 0, sizeof *sp);
869
870	sp->se_flags = SE_PRESENT;
871	sp->se_index = session_index;
872
873	len = sizeof(_PATH_DEV) + strlen(typ->ty_name);
874	sp->se_device = malloc(len);
875	(void) snprintf(sp->se_device, len, "%s%s", _PATH_DEV, typ->ty_name);
876
877	if (setupargv(sp, typ) == 0) {
878		free_session(sp);
879		return (0);
880	}
881
882	sp->se_next = 0;
883	if (sprev == 0) {
884		sessions = sp;
885		sp->se_prev = 0;
886	} else {
887		sprev->se_next = sp;
888		sp->se_prev = sprev;
889	}
890
891	return (sp);
892}
893
894/*
895 * Calculate getty and if useful window argv vectors.
896 */
897int
898setupargv(session_t *sp, struct ttyent *typ)
899{
900	size_t len;
901
902	if (sp->se_getty) {
903		free(sp->se_getty);
904		free(sp->se_getty_argv);
905	}
906	len = strlen(typ->ty_getty) + strlen(typ->ty_name) + 2;
907	sp->se_getty = malloc(len);
908	(void) snprintf(sp->se_getty, len, "%s %s", typ->ty_getty, typ->ty_name);
909	sp->se_getty_argv = construct_argv(sp->se_getty);
910	if (sp->se_getty_argv == 0) {
911		warning("can't parse getty for port %s", sp->se_device);
912		free(sp->se_getty);
913		sp->se_getty = 0;
914		return (0);
915	}
916	if (typ->ty_window) {
917		if (sp->se_window)
918			free(sp->se_window);
919		sp->se_window = strdup(typ->ty_window);
920		if (sp->se_window == NULL) {
921			warning("can't allocate window");
922			return (0);
923		}
924		sp->se_window_argv = construct_argv(sp->se_window);
925		if (sp->se_window_argv == NULL) {
926			warning("can't parse window for port %s",
927			    sp->se_device);
928			free(sp->se_window);
929			sp->se_window = NULL;
930			return (0);
931		}
932	}
933	return (1);
934}
935
936/*
937 * Walk the list of ttys and create sessions for each active line.
938 */
939state_func_t
940read_ttys(void)
941{
942	int session_index = 0;
943	session_t *sp, *snext;
944	struct ttyent *typ;
945
946	/*
947	 * Destroy any previous session state.
948	 * There shouldn't be any, but just in case...
949	 */
950	for (sp = sessions; sp; sp = snext) {
951		if (sp->se_process)
952			clear_session_logs(sp);
953		snext = sp->se_next;
954		free_session(sp);
955	}
956	sessions = 0;
957	if (start_session_db())
958		return (state_func_t) single_user;
959
960	/*
961	 * Allocate a session entry for each active port.
962	 * Note that sp starts at 0.
963	 */
964	while ((typ = getttyent()))
965		if ((snext = new_session(sp, ++session_index, typ)))
966			sp = snext;
967
968	endttyent();
969
970	return (state_func_t) multi_user;
971}
972
973/*
974 * Start a window system running.
975 */
976void
977start_window_system(session_t *sp)
978{
979	pid_t pid;
980	sigset_t mask;
981
982	if ((pid = fork()) == -1) {
983		emergency("can't fork for window system on port %s: %m",
984		    sp->se_device);
985		/* hope that getty fails and we can try again */
986		return;
987	}
988
989	if (pid)
990		return;
991
992	sigemptyset(&mask);
993	sigprocmask(SIG_SETMASK, &mask, NULL);
994
995	if (setsid() < 0)
996		emergency("setsid failed (window) %m");
997
998	setprocresources(RESOURCE_WINDOW);
999
1000	execv(sp->se_window_argv[0], sp->se_window_argv);
1001	stall("can't exec window system '%s' for port %s: %m",
1002	    sp->se_window_argv[0], sp->se_device);
1003	_exit(1);
1004}
1005
1006/*
1007 * Start a login session running.
1008 * For first open, man-handle tty directly to determine if it
1009 * really exists. It is not efficient to spawn gettys on devices
1010 * that do not exist.
1011 */
1012pid_t
1013start_getty(session_t *sp)
1014{
1015	pid_t pid;
1016	sigset_t mask;
1017	time_t current_time = time(NULL);
1018	int p[2], new = 1;
1019
1020	if (sp->se_flags & SE_DEVEXISTS)
1021		new = 0;
1022
1023	if (new) {
1024		if (pipe(p) == -1)
1025			return (-1);
1026	}
1027
1028	/*
1029	 * fork(), not vfork() -- we can't afford to block.
1030	 */
1031	if ((pid = fork()) == -1) {
1032		emergency("can't fork for getty on port %s: %m", sp->se_device);
1033		return (-1);
1034	}
1035
1036	if (pid) {
1037		if (new) {
1038			char c;
1039
1040			close(p[1]);
1041			if (read(p[0], &c, 1) != 1) {
1042				close(p[0]);
1043				return (-1);
1044			}
1045			close(p[0]);
1046			if (c == '1')
1047				sp->se_flags |= SE_DEVEXISTS;
1048			else
1049				sp->se_flags |= SE_SHUTDOWN;
1050		}
1051		return (pid);
1052	}
1053	if (new) {
1054		int fd;
1055
1056		close(p[0]);
1057		fd = open(sp->se_device, O_RDONLY | O_NONBLOCK, 0666);
1058		if (fd == -1 && (errno == ENXIO || errno == ENOENT ||
1059		    errno == EISDIR)) {
1060			(void)write(p[1], "0", 1);
1061			close(p[1]);
1062			_exit(1);
1063		}
1064		(void)write(p[1], "1", 1);
1065		close(p[1]);
1066		close(fd);
1067		sleep(1);
1068	}
1069
1070	if (current_time > sp->se_started &&
1071	    current_time - sp->se_started < GETTY_SPACING) {
1072		warning("getty repeating too quickly on port %s, sleeping",
1073		    sp->se_device);
1074		sleep((unsigned) GETTY_SLEEP);
1075	}
1076
1077	if (sp->se_window) {
1078		start_window_system(sp);
1079		sleep(WINDOW_WAIT);
1080	}
1081
1082	sigemptyset(&mask);
1083	sigprocmask(SIG_SETMASK, &mask, NULL);
1084
1085	setprocresources(RESOURCE_GETTY);
1086
1087	execv(sp->se_getty_argv[0], sp->se_getty_argv);
1088	stall("can't exec getty '%s' for port %s: %m",
1089	    sp->se_getty_argv[0], sp->se_device);
1090	_exit(1);
1091}
1092
1093/*
1094 * Collect exit status for a child.
1095 * If an exiting login, start a new login running.
1096 */
1097void
1098collect_child(pid_t pid)
1099{
1100	session_t *sp, *sprev, *snext;
1101
1102	if (sessions == NULL)
1103		return;
1104
1105	if ((sp = find_session(pid)) == NULL)
1106		return;
1107
1108	clear_session_logs(sp);
1109	login_fbtab(sp->se_device + sizeof(_PATH_DEV) - 1, 0, 0);
1110	del_session(sp);
1111	sp->se_process = 0;
1112
1113	if (sp->se_flags & SE_SHUTDOWN) {
1114		if ((sprev = sp->se_prev))
1115			sprev->se_next = sp->se_next;
1116		else
1117			sessions = sp->se_next;
1118		if ((snext = sp->se_next))
1119			snext->se_prev = sp->se_prev;
1120		free_session(sp);
1121		return;
1122	}
1123
1124	if ((pid = start_getty(sp)) == -1) {
1125		/* serious trouble */
1126		requested_transition = clean_ttys;
1127		return;
1128	}
1129
1130	sp->se_process = pid;
1131	sp->se_started = time(NULL);
1132	add_session(sp);
1133}
1134
1135/*
1136 * Catch a signal and request a state transition.
1137 */
1138void
1139transition_handler(int sig)
1140{
1141
1142	switch (sig) {
1143	case SIGHUP:
1144		requested_transition = clean_ttys;
1145		break;
1146	case SIGTERM:
1147		requested_transition = death;
1148		break;
1149	case SIGUSR1:
1150		requested_transition = nice_death;
1151		break;
1152	case SIGTSTP:
1153		requested_transition = catatonia;
1154		break;
1155	default:
1156		requested_transition = 0;
1157		break;
1158	}
1159}
1160
1161/*
1162 * Take the system multiuser.
1163 */
1164state_func_t
1165multi_user(void)
1166{
1167	pid_t pid;
1168	session_t *sp;
1169
1170	requested_transition = 0;
1171
1172	/*
1173	 * If the administrator has not set the security level to -1
1174	 * to indicate that the kernel should not run multiuser in secure
1175	 * mode, and the run script has not set a higher level of security
1176	 * than level 1, then put the kernel into secure mode.
1177	 */
1178	if (getsecuritylevel() == 0)
1179		setsecuritylevel(1);
1180
1181	for (sp = sessions; sp; sp = sp->se_next) {
1182		if (sp->se_process)
1183			continue;
1184		if ((pid = start_getty(sp)) == -1) {
1185			/* serious trouble */
1186			requested_transition = clean_ttys;
1187			break;
1188		}
1189		sp->se_process = pid;
1190		sp->se_started = time(NULL);
1191		add_session(sp);
1192	}
1193
1194	while (!requested_transition)
1195		if ((pid = waitpid(-1, NULL, 0)) != -1)
1196			collect_child(pid);
1197
1198	return (state_func_t) requested_transition;
1199}
1200
1201/*
1202 * This is an n-squared algorithm.  We hope it isn't run often...
1203 */
1204state_func_t
1205clean_ttys(void)
1206{
1207	session_t *sp, *sprev;
1208	struct ttyent *typ;
1209	int session_index = 0;
1210	int devlen;
1211
1212	for (sp = sessions; sp; sp = sp->se_next)
1213		sp->se_flags &= ~SE_PRESENT;
1214
1215	devlen = sizeof(_PATH_DEV) - 1;
1216	while ((typ = getttyent())) {
1217		++session_index;
1218
1219		for (sprev = 0, sp = sessions; sp; sprev = sp, sp = sp->se_next)
1220			if (strcmp(typ->ty_name, sp->se_device + devlen) == 0)
1221				break;
1222
1223		if (sp) {
1224			sp->se_flags |= SE_PRESENT;
1225			if (sp->se_index != session_index) {
1226				warning("port %s changed utmp index from %d to %d",
1227				    sp->se_device, sp->se_index,
1228				    session_index);
1229				sp->se_index = session_index;
1230			}
1231			if ((typ->ty_status & TTY_ON) == 0 ||
1232			    typ->ty_getty == 0) {
1233				sp->se_flags |= SE_SHUTDOWN;
1234				kill(sp->se_process, SIGHUP);
1235				continue;
1236			}
1237			sp->se_flags &= ~SE_SHUTDOWN;
1238			if (setupargv(sp, typ) == 0) {
1239				warning("can't parse getty for port %s",
1240				    sp->se_device);
1241				sp->se_flags |= SE_SHUTDOWN;
1242				kill(sp->se_process, SIGHUP);
1243			}
1244			continue;
1245		}
1246
1247		new_session(sprev, session_index, typ);
1248	}
1249
1250	endttyent();
1251
1252	for (sp = sessions; sp; sp = sp->se_next)
1253		if ((sp->se_flags & SE_PRESENT) == 0) {
1254			sp->se_flags |= SE_SHUTDOWN;
1255			kill(sp->se_process, SIGHUP);
1256		}
1257
1258	return (state_func_t) multi_user;
1259}
1260
1261/*
1262 * Block further logins.
1263 */
1264state_func_t
1265catatonia(void)
1266{
1267	session_t *sp;
1268
1269	for (sp = sessions; sp; sp = sp->se_next)
1270		sp->se_flags |= SE_SHUTDOWN;
1271
1272	return (state_func_t) multi_user;
1273}
1274
1275/*
1276 * Note SIGALRM.
1277 */
1278void
1279alrm_handler(int sig)
1280{
1281	clang = 1;
1282}
1283
1284/*
1285 * Bring the system down to single user nicely, after run the shutdown script.
1286 */
1287state_func_t
1288nice_death(void)
1289{
1290	session_t *sp;
1291	int i;
1292	pid_t pid;
1293	static const int death_sigs[3] = { SIGHUP, SIGTERM, SIGKILL };
1294	int howto = RB_HALT;
1295	int status;
1296
1297	for (sp = sessions; sp; sp = sp->se_next) {
1298		sp->se_flags &= ~SE_PRESENT;
1299		sp->se_flags |= SE_SHUTDOWN;
1300		kill(sp->se_process, SIGHUP);
1301	}
1302
1303	/* NB: should send a message to the session logger to avoid blocking. */
1304	logwtmp("~", "shutdown", "");
1305
1306	if (access(_PATH_RUNCOM, R_OK) != -1) {
1307		pid_t pid;
1308		struct sigaction sa;
1309
1310		switch ((pid = fork())) {
1311		case -1:
1312			break;
1313		case 0:
1314
1315			memset(&sa, 0, sizeof sa);
1316			sigemptyset(&sa.sa_mask);
1317			sa.sa_flags = 0;
1318			sa.sa_handler = SIG_IGN;
1319			(void) sigaction(SIGTSTP, &sa, NULL);
1320			(void) sigaction(SIGHUP, &sa, NULL);
1321
1322			setctty(_PATH_CONSOLE);
1323
1324			sigprocmask(SIG_SETMASK, &sa.sa_mask, NULL);
1325
1326			execl(_PATH_BSHELL, "sh", _PATH_RUNCOM, "shutdown",
1327			    (char *)NULL);
1328			stall("can't exec %s for %s %s: %m", _PATH_BSHELL,
1329			    _PATH_RUNCOM, "shutdown");
1330			_exit(1);
1331		default:
1332			waitpid(pid, &status, 0);
1333			if (WIFEXITED(status) && WEXITSTATUS(status) == 2)
1334				howto |= RB_POWERDOWN;
1335		}
1336	}
1337
1338	for (i = 0; i < 3; ++i) {
1339		if (kill(-1, death_sigs[i]) == -1 && errno == ESRCH)
1340			goto die;
1341
1342		clang = 0;
1343		alarm(DEATH_WATCH);
1344		do {
1345			if ((pid = waitpid(-1, NULL, 0)) != -1)
1346				collect_child(pid);
1347		} while (clang == 0 && errno != ECHILD);
1348
1349		if (errno == ECHILD)
1350			goto die;
1351	}
1352
1353	warning("some processes would not die; ps axl advised");
1354
1355die:
1356	reboot(howto);
1357
1358	/* ... and if that fails.. oh well */
1359	return (state_func_t) single_user;
1360}
1361
1362/*
1363 * Bring the system down to single user.
1364 */
1365state_func_t
1366death(void)
1367{
1368	session_t *sp;
1369	int i;
1370	pid_t pid;
1371	static const int death_sigs[3] = { SIGHUP, SIGTERM, SIGKILL };
1372
1373	for (sp = sessions; sp; sp = sp->se_next)
1374		sp->se_flags |= SE_SHUTDOWN;
1375
1376	/* NB: should send a message to the session logger to avoid blocking. */
1377	logwtmp("~", "shutdown", "");
1378
1379	for (i = 0; i < 3; ++i) {
1380		if (kill(-1, death_sigs[i]) == -1 && errno == ESRCH)
1381			return (state_func_t) single_user;
1382
1383		clang = 0;
1384		alarm(DEATH_WATCH);
1385		do {
1386			if ((pid = waitpid(-1, NULL, 0)) != -1)
1387				collect_child(pid);
1388		} while (clang == 0 && errno != ECHILD);
1389
1390		if (errno == ECHILD)
1391			return (state_func_t) single_user;
1392	}
1393
1394	warning("some processes would not die; ps axl advised");
1395
1396	return (state_func_t) single_user;
1397}
1398
1399#ifdef LOGIN_CAP
1400void
1401setprocresources(char *class)
1402{
1403	login_cap_t *lc;
1404
1405	if ((lc = login_getclass(class)) != NULL) {
1406		setusercontext(lc, NULL, 0,
1407		    LOGIN_SETPRIORITY|LOGIN_SETRESOURCES|LOGIN_SETUMASK);
1408		login_close(lc);
1409	}
1410}
1411#endif
1412