init.c revision 1.18 
1/*	$OpenBSD: init.c,v 1.18 2000/01/22 20:24:58 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 1.18 2000/01/22 20:24:58 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 <stdio.h>
64#include <stdlib.h>
65#include <string.h>
66#include <syslog.h>
67#include <time.h>
68#include <ttyent.h>
69#include <unistd.h>
70#include <util.h>
71
72#ifdef __STDC__
73#include <stdarg.h>
74#else
75#include <varargs.h>
76#endif
77
78#ifdef SECURE
79#include <pwd.h>
80#endif
81
82#include "pathnames.h"
83
84/*
85 * Sleep times; used to prevent thrashing.
86 */
87#define	GETTY_SPACING		 5	/* N secs minimum getty spacing */
88#define	GETTY_SLEEP		30	/* sleep N secs after spacing problem */
89#define	WINDOW_WAIT		 3	/* wait N secs after starting window */
90#define	STALL_TIMEOUT		30	/* wait N secs after warning */
91#define	DEATH_WATCH		10	/* wait N secs for procs to die */
92
93void handle __P((sig_t, ...));
94void delset __P((sigset_t *, ...));
95
96void stall __P((char *, ...));
97void warning __P((char *, ...));
98void emergency __P((char *, ...));
99void disaster __P((int));
100void badsys __P((int));
101
102/*
103 * We really need a recursive typedef...
104 * The following at least guarantees that the return type of (*state_t)()
105 * is sufficiently wide to hold a function pointer.
106 */
107typedef long (*state_func_t) __P((void));
108typedef state_func_t (*state_t) __P((void));
109
110state_func_t single_user __P((void));
111state_func_t runcom __P((void));
112state_func_t read_ttys __P((void));
113state_func_t multi_user __P((void));
114state_func_t clean_ttys __P((void));
115state_func_t catatonia __P((void));
116state_func_t death __P((void));
117state_func_t nice_death __P((void));
118
119enum { AUTOBOOT, FASTBOOT } runcom_mode = AUTOBOOT;
120
121void transition __P((state_t));
122state_t requested_transition = runcom;
123
124void setctty __P((char *));
125
126typedef struct init_session {
127	int	se_index;		/* index of entry in ttys file */
128	pid_t	se_process;		/* controlling process */
129	time_t	se_started;		/* used to avoid thrashing */
130	int	se_flags;		/* status of session */
131#define	SE_SHUTDOWN	0x1		/* session won't be restarted */
132#define	SE_PRESENT	0x2		/* session is in /etc/ttys */
133#define	SE_DEVEXISTS	0x4		/* open does not result in ENODEV */
134	char	*se_device;		/* filename of port */
135	char	*se_getty;		/* what to run on that port */
136	char	**se_getty_argv;	/* pre-parsed argument array */
137	char	*se_window;		/* window system (started only once) */
138	char	**se_window_argv;	/* pre-parsed argument array */
139	struct	init_session *se_prev;
140	struct	init_session *se_next;
141} session_t;
142
143void free_session __P((session_t *));
144session_t *new_session __P((session_t *, int, struct ttyent *));
145session_t *sessions;
146
147char **construct_argv __P((char *));
148void start_window_system __P((session_t *));
149void collect_child __P((pid_t));
150pid_t start_getty __P((session_t *));
151void transition_handler __P((int));
152void alrm_handler __P((int));
153void setsecuritylevel __P((int));
154int getsecuritylevel __P((void));
155int setupargv __P((session_t *, struct ttyent *));
156int clang;
157
158void clear_session_logs __P((session_t *));
159
160int start_session_db __P((void));
161void add_session __P((session_t *));
162void del_session __P((session_t *));
163session_t *find_session __P((pid_t));
164DB *session_db;
165
166/*
167 * The mother of all processes.
168 */
169int
170main(argc, argv)
171	int argc;
172	char **argv;
173{
174	int c;
175	struct sigaction sa;
176	sigset_t mask;
177
178	/* Dispose of random users. */
179	if (getuid() != 0) {
180		(void)fprintf(stderr, "init: %s\n", strerror(EPERM));
181		exit (1);
182	}
183
184	/* System V users like to reexec init. */
185	if (getpid() != 1) {
186		(void)fprintf(stderr, "init: already running\n");
187		exit (1);
188	}
189
190	/*
191	 * Note that this does NOT open a file...
192	 * Does 'init' deserve its own facility number?
193	 */
194	openlog("init", LOG_CONS|LOG_ODELAY, LOG_AUTH);
195
196	/*
197	 * Create an initial session.
198	 */
199	if (setsid() < 0)
200		warning("initial setsid() failed: %m");
201
202	/*
203	 * Establish an initial user so that programs running
204	 * single user do not freak out and die (like passwd).
205	 */
206	if (setlogin("root") < 0)
207		warning("setlogin() failed: %m");
208
209	/*
210	 * This code assumes that we always get arguments through flags,
211	 * never through bits set in some random machine register.
212	 */
213	while ((c = getopt(argc, argv, "sf")) != -1)
214		switch (c) {
215		case 's':
216			requested_transition = single_user;
217			break;
218		case 'f':
219			runcom_mode = FASTBOOT;
220			break;
221		default:
222			warning("unrecognized flag '-%c'", c);
223			break;
224		}
225
226	if (optind != argc)
227		warning("ignoring excess arguments");
228
229	/*
230	 * We catch or block signals rather than ignore them,
231	 * so that they get reset on exec.
232	 */
233	handle(badsys, SIGSYS, 0);
234	handle(disaster, SIGABRT, SIGFPE, SIGILL, SIGSEGV,
235	       SIGBUS, SIGXCPU, SIGXFSZ, 0);
236	handle(transition_handler, SIGHUP, SIGTERM, SIGTSTP, SIGUSR1, 0);
237	handle(alrm_handler, SIGALRM, 0);
238	sigfillset(&mask);
239	delset(&mask, SIGABRT, SIGFPE, SIGILL, SIGSEGV, SIGBUS, SIGSYS,
240		SIGXCPU, SIGXFSZ, SIGHUP, SIGTERM, SIGUSR1, SIGTSTP, SIGALRM, 0);
241	sigprocmask(SIG_SETMASK, &mask, NULL);
242	memset(&sa, 0, sizeof sa);
243	sigemptyset(&sa.sa_mask);
244	sa.sa_flags = 0;
245	sa.sa_handler = SIG_IGN;
246	(void) sigaction(SIGTTIN, &sa, NULL);
247	(void) sigaction(SIGTTOU, &sa, NULL);
248
249	/*
250	 * Paranoia.
251	 */
252	close(0);
253	close(1);
254	close(2);
255
256	/*
257	 * Start the state machine.
258	 */
259	transition(requested_transition);
260
261	/*
262	 * Should never reach here.
263	 */
264	return 1;
265}
266
267/*
268 * Associate a function with a signal handler.
269 */
270void
271#ifdef __STDC__
272handle(sig_t handler, ...)
273#else
274handle(va_alist)
275	va_dcl
276#endif
277{
278	int sig;
279	struct sigaction sa;
280	sigset_t mask_everything;
281	va_list ap;
282#ifndef __STDC__
283	sig_t handler;
284
285	va_start(ap);
286	handler = va_arg(ap, sig_t);
287#else
288	va_start(ap, handler);
289#endif
290
291	memset(&sa, 0, sizeof sa);
292	sa.sa_handler = handler;
293	sigfillset(&mask_everything);
294
295	while ((sig = va_arg(ap, int))) {
296		sa.sa_mask = mask_everything;
297		/* XXX SA_RESTART? */
298		sa.sa_flags = sig == SIGCHLD ? SA_NOCLDSTOP : 0;
299		sigaction(sig, &sa, NULL);
300	}
301	va_end(ap);
302}
303
304/*
305 * Delete a set of signals from a mask.
306 */
307void
308#ifdef __STDC__
309delset(sigset_t *maskp, ...)
310#else
311delset(va_alist)
312	va_dcl
313#endif
314{
315	int sig;
316	va_list ap;
317#ifndef __STDC__
318	sigset_t *maskp;
319
320	va_start(ap);
321	maskp = va_arg(ap, sigset_t *);
322#else
323	va_start(ap, maskp);
324#endif
325
326	while ((sig = va_arg(ap, int)))
327		sigdelset(maskp, sig);
328	va_end(ap);
329}
330
331/*
332 * Log a message and sleep for a while (to give someone an opportunity
333 * to read it and to save log or hardcopy output if the problem is chronic).
334 * NB: should send a message to the session logger to avoid blocking.
335 */
336void
337#ifdef __STDC__
338stall(char *message, ...)
339#else
340stall(va_alist)
341	va_dcl
342#endif
343{
344	va_list ap;
345#ifndef __STDC__
346	char *message;
347
348	va_start(ap);
349	message = va_arg(ap, char *);
350#else
351	va_start(ap, message);
352#endif
353
354	vsyslog(LOG_ALERT, message, ap);
355	va_end(ap);
356	closelog();
357	sleep(STALL_TIMEOUT);
358}
359
360/*
361 * Like stall(), but doesn't sleep.
362 * If cpp had variadic macros, the two functions could be #defines for another.
363 * NB: should send a message to the session logger to avoid blocking.
364 */
365void
366#ifdef __STDC__
367warning(char *message, ...)
368#else
369warning(va_alist)
370	va_dcl
371#endif
372{
373	va_list ap;
374#ifndef __STDC__
375	char *message;
376
377	va_start(ap);
378	message = va_arg(ap, char *);
379#else
380	va_start(ap, message);
381#endif
382
383	vsyslog(LOG_ALERT, message, ap);
384	va_end(ap);
385	closelog();
386}
387
388/*
389 * Log an emergency message.
390 * NB: should send a message to the session logger to avoid blocking.
391 */
392void
393#ifdef __STDC__
394emergency(char *message, ...)
395#else
396emergency(va_alist)
397	va_dcl
398#endif
399{
400	va_list ap;
401#ifndef __STDC__
402	char *message;
403
404	va_start(ap);
405	message = va_arg(ap, char *);
406#else
407	va_start(ap, message);
408#endif
409
410	vsyslog(LOG_EMERG, message, ap);
411	va_end(ap);
412	closelog();
413}
414
415/*
416 * Catch a SIGSYS signal.
417 *
418 * These may arise if a system does not support sysctl.
419 * We tolerate up to 25 of these, then throw in the towel.
420 */
421void
422badsys(sig)
423	int sig;
424{
425	static int badcount = 0;
426
427	if (badcount++ < 25)
428		return;
429	disaster(sig);
430}
431
432/*
433 * Catch an unexpected signal.
434 */
435void
436disaster(sig)
437	int sig;
438{
439	emergency("fatal signal: %s", strsignal(sig));
440
441	sleep(STALL_TIMEOUT);
442	_exit(sig);		/* reboot */
443}
444
445/*
446 * Get the security level of the kernel.
447 */
448int
449getsecuritylevel()
450{
451#ifdef KERN_SECURELVL
452	int name[2], curlevel;
453	size_t len;
454
455	name[0] = CTL_KERN;
456	name[1] = KERN_SECURELVL;
457	len = sizeof curlevel;
458	if (sysctl(name, 2, &curlevel, &len, NULL, 0) == -1) {
459		emergency("cannot get kernel security level: %s",
460		    strerror(errno));
461		return (-1);
462	}
463	return (curlevel);
464#else
465	return (-1);
466#endif
467}
468
469/*
470 * Set the security level of the kernel.
471 */
472void
473setsecuritylevel(newlevel)
474	int newlevel;
475{
476#ifdef KERN_SECURELVL
477	int name[2], curlevel;
478	extern int errno;
479
480	curlevel = getsecuritylevel();
481	if (newlevel == curlevel)
482		return;
483	name[0] = CTL_KERN;
484	name[1] = KERN_SECURELVL;
485	if (sysctl(name, 2, NULL, NULL, &newlevel, sizeof newlevel) == -1) {
486		emergency(
487		    "cannot change kernel security level from %d to %d: %s",
488		    curlevel, newlevel, strerror(errno));
489		return;
490	}
491#ifdef SECURE
492	warning("kernel security level changed from %d to %d",
493	    curlevel, newlevel);
494#endif
495#endif
496}
497
498/*
499 * Change states in the finite state machine.
500 * The initial state is passed as an argument.
501 */
502void
503transition(s)
504	state_t s;
505{
506	for (;;)
507		s = (state_t) (*s)();
508}
509
510/*
511 * Close out the accounting files for a login session.
512 * NB: should send a message to the session logger to avoid blocking.
513 */
514void
515clear_session_logs(sp)
516	session_t *sp;
517{
518	char *line = sp->se_device + sizeof(_PATH_DEV) - 1;
519
520	if (logout(line))
521		logwtmp(line, "", "");
522}
523
524/*
525 * Start a session and allocate a controlling terminal.
526 * Only called by children of init after forking.
527 */
528void
529setctty(name)
530	char *name;
531{
532	int fd;
533
534	(void) revoke(name);
535	sleep (2);			/* leave DTR low */
536	if ((fd = open(name, O_RDWR)) == -1) {
537		stall("can't open %s: %m", name);
538		_exit(1);
539	}
540	if (login_tty(fd) == -1) {
541		stall("can't get %s for controlling terminal: %m", name);
542		_exit(1);
543	}
544}
545
546/*
547 * Bring the system up single user.
548 */
549state_func_t
550single_user()
551{
552	pid_t pid, wpid;
553	int status;
554	sigset_t mask;
555	char shell[MAXPATHLEN];		/* Allocate space here */
556	char name[MAXPATHLEN];		/* Name (argv[0]) of shell */
557	char *argv[2];
558#ifdef SECURE
559	struct ttyent *typ;
560	struct passwd *pp;
561	static const char banner[] =
562		"Enter root password, or ^D to go multi-user\n";
563	char *clear, *password;
564#endif
565
566	/* Init shell and name */
567	strcpy(shell, _PATH_BSHELL);
568	strcpy(name, "-sh");
569
570	/*
571	 * If the kernel is in secure mode, downgrade it to insecure mode.
572	 */
573	if (getsecuritylevel() > 0)
574		setsecuritylevel(0);
575
576	if ((pid = fork()) == 0) {
577		/*
578		 * Start the single user session.
579		 */
580		setctty(_PATH_CONSOLE);
581
582#ifdef SECURE
583		/*
584		 * Check the root password.
585		 * We don't care if the console is 'on' by default;
586		 * it's the only tty that can be 'off' and 'secure'.
587		 */
588		typ = getttynam("console");
589		pp = getpwnam("root");
590		if (typ && (typ->ty_status & TTY_SECURE) == 0 && pp &&
591		    *pp->pw_passwd) {
592			write(2, banner, sizeof banner - 1);
593			for (;;) {
594				clear = getpass("Password:");
595				if (clear == 0 || *clear == '\0')
596					_exit(0);
597				password = crypt(clear, pp->pw_passwd);
598				memset(clear, 0, _PASSWORD_LEN);
599				if (strcmp(password, pp->pw_passwd) == 0)
600					break;
601				warning("single-user login failed\n");
602			}
603		}
604		endttyent();
605		endpwent();
606#endif /* SECURE */
607
608#ifdef DEBUGSHELL
609		{
610			char altshell[128], *cp = altshell;
611			int num;
612
613#define	SHREQUEST \
614	"Enter pathname of shell or RETURN for sh: "
615			(void)write(STDERR_FILENO,
616			    SHREQUEST, sizeof(SHREQUEST) - 1);
617			while ((num = read(STDIN_FILENO, cp, 1)) != -1 &&
618			    num != 0 && *cp != '\n' && cp < &altshell[127])
619					cp++;
620			*cp = '\0';
621
622			/* Copy in alternate shell */
623			if (altshell[0] != '\0'){
624				char *p;
625
626				/* Binary to exec */
627				strcpy(shell, altshell);
628
629				/* argv[0] */
630				p = strrchr(altshell, '/');
631				if(p == NULL) p = altshell;
632				else p++;
633
634				name[0] = '-';
635				strcpy(&name[1], p);
636			}
637		}
638#endif /* DEBUGSHELL */
639
640		/*
641		 * Unblock signals.
642		 * We catch all the interesting ones,
643		 * and those are reset to SIG_DFL on exec.
644		 */
645		sigemptyset(&mask);
646		sigprocmask(SIG_SETMASK, &mask, NULL);
647
648		/*
649		 * Fire off a shell.
650		 * If the default one doesn't work, try the Bourne shell.
651		 */
652		argv[0] = name;
653		argv[1] = NULL;
654		setenv("PATH", _PATH_STDPATH, 1);
655		execv(shell, argv);
656		emergency("can't exec %s for single user: %m", shell);
657
658		argv[0] = "-sh";
659		argv[1] = NULL;
660		execv(_PATH_BSHELL, argv);
661		emergency("can't exec %s for single user: %m", _PATH_BSHELL);
662		sleep(STALL_TIMEOUT);
663		_exit(1);
664	}
665
666	if (pid == -1) {
667		/*
668		 * We are seriously hosed.  Do our best.
669		 */
670		emergency("can't fork single-user shell, trying again");
671		while (waitpid(-1, NULL, WNOHANG) > 0)
672			continue;
673		return (state_func_t) single_user;
674	}
675
676	requested_transition = 0;
677	do {
678		if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1)
679			collect_child(wpid);
680		if (wpid == -1) {
681			if (errno == EINTR)
682				continue;
683			warning("wait for single-user shell failed: %m; restarting");
684			return (state_func_t) single_user;
685		}
686		if (wpid == pid && WIFSTOPPED(status)) {
687			warning("init: shell stopped, restarting\n");
688			kill(pid, SIGCONT);
689			wpid = -1;
690		}
691	} while (wpid != pid && !requested_transition);
692
693	if (requested_transition)
694		return (state_func_t) requested_transition;
695
696	if (!WIFEXITED(status)) {
697		if (WTERMSIG(status) == SIGKILL) {
698			/*
699			 *  reboot(8) killed shell?
700			 */
701			warning("single user shell terminated.");
702			sleep(STALL_TIMEOUT);
703			_exit(0);
704		} else {
705			warning("single user shell terminated, restarting");
706			return (state_func_t) single_user;
707		}
708	}
709
710	runcom_mode = FASTBOOT;
711	return (state_func_t) runcom;
712}
713
714/*
715 * Run the system startup script.
716 */
717state_func_t
718runcom()
719{
720	pid_t pid, wpid;
721	int status;
722	char *argv[4];
723	struct sigaction sa;
724
725	if ((pid = fork()) == 0) {
726		memset(&sa, 0, sizeof sa);
727		sigemptyset(&sa.sa_mask);
728		sa.sa_flags = 0;
729		sa.sa_handler = SIG_IGN;
730		(void) sigaction(SIGTSTP, &sa, NULL);
731		(void) sigaction(SIGHUP, &sa, NULL);
732
733		setctty(_PATH_CONSOLE);
734
735		argv[0] = "sh";
736		argv[1] = _PATH_RUNCOM;
737		argv[2] = runcom_mode == AUTOBOOT ? "autoboot" : 0;
738		argv[3] = 0;
739
740		sigprocmask(SIG_SETMASK, &sa.sa_mask, NULL);
741
742		execv(_PATH_BSHELL, argv);
743		stall("can't exec %s for %s: %m", _PATH_BSHELL, _PATH_RUNCOM);
744		_exit(1);	/* force single user mode */
745	}
746
747	if (pid == -1) {
748		emergency("can't fork for %s on %s: %m",
749			_PATH_BSHELL, _PATH_RUNCOM);
750		while (waitpid(-1, NULL, WNOHANG) > 0)
751			continue;
752		sleep(STALL_TIMEOUT);
753		return (state_func_t) single_user;
754	}
755
756	/*
757	 * Copied from single_user().  This is a bit paranoid.
758	 */
759	do {
760		if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1)
761			collect_child(wpid);
762		if (wpid == -1) {
763			if (errno == EINTR)
764				continue;
765			warning("wait for %s on %s failed: %m; going to single user mode",
766				_PATH_BSHELL, _PATH_RUNCOM);
767			return (state_func_t) single_user;
768		}
769		if (wpid == pid && WIFSTOPPED(status)) {
770			warning("init: %s on %s stopped, restarting\n",
771				_PATH_BSHELL, _PATH_RUNCOM);
772			kill(pid, SIGCONT);
773			wpid = -1;
774		}
775	} while (wpid != pid);
776
777	if (WIFSIGNALED(status) && WTERMSIG(status) == SIGTERM &&
778	    requested_transition == catatonia) {
779		/* /etc/rc executed /sbin/reboot; wait for the end quietly */
780		sigset_t s;
781
782		sigfillset(&s);
783		for (;;)
784			sigsuspend(&s);
785	}
786
787	if (!WIFEXITED(status)) {
788		warning("%s on %s terminated abnormally, going to single user mode",
789			_PATH_BSHELL, _PATH_RUNCOM);
790		return (state_func_t) single_user;
791	}
792
793	if (WEXITSTATUS(status))
794		return (state_func_t) single_user;
795
796	runcom_mode = AUTOBOOT;		/* the default */
797	/* NB: should send a message to the session logger to avoid blocking. */
798	logwtmp("~", "reboot", "");
799	return (state_func_t) read_ttys;
800}
801
802/*
803 * Open the session database.
804 *
805 * NB: We could pass in the size here; is it necessary?
806 */
807int
808start_session_db()
809{
810	if (session_db && (*session_db->close)(session_db))
811		emergency("session database close: %s", strerror(errno));
812	if ((session_db = dbopen(NULL, O_RDWR, 0, DB_HASH, NULL)) == 0) {
813		emergency("session database open: %s", strerror(errno));
814		return (1);
815	}
816	return (0);
817
818}
819
820/*
821 * Add a new login session.
822 */
823void
824add_session(sp)
825	session_t *sp;
826{
827	DBT key;
828	DBT data;
829
830	key.data = &sp->se_process;
831	key.size = sizeof sp->se_process;
832	data.data = &sp;
833	data.size = sizeof sp;
834
835	if ((*session_db->put)(session_db, &key, &data, 0))
836		emergency("insert %d: %s", sp->se_process, strerror(errno));
837}
838
839/*
840 * Delete an old login session.
841 */
842void
843del_session(sp)
844	session_t *sp;
845{
846	DBT key;
847
848	key.data = &sp->se_process;
849	key.size = sizeof sp->se_process;
850
851	if ((*session_db->del)(session_db, &key, 0))
852		emergency("delete %d: %s", sp->se_process, strerror(errno));
853}
854
855/*
856 * Look up a login session by pid.
857 */
858session_t *
859#ifdef __STDC__
860find_session(pid_t pid)
861#else
862find_session(pid)
863	pid_t pid;
864#endif
865{
866	DBT key;
867	DBT data;
868	session_t *ret;
869
870	key.data = &pid;
871	key.size = sizeof pid;
872	if ((*session_db->get)(session_db, &key, &data, 0) != 0)
873		return 0;
874	memcpy(&ret, data.data, sizeof(ret));
875	return ret;
876}
877
878/*
879 * Construct an argument vector from a command line.
880 */
881char **
882construct_argv(command)
883	char *command;
884{
885	register int argc = 0;
886	register char **argv = (char **) malloc(((strlen(command) + 1) / 2 + 1)
887						* sizeof (char *));
888	static const char separators[] = " \t";
889
890	if ((argv[argc++] = strtok(command, separators)) == 0)
891		return 0;
892	while ((argv[argc++] = strtok(NULL, separators)))
893		continue;
894	return argv;
895}
896
897/*
898 * Deallocate a session descriptor.
899 */
900void
901free_session(sp)
902	register session_t *sp;
903{
904	free(sp->se_device);
905	if (sp->se_getty) {
906		free(sp->se_getty);
907		free(sp->se_getty_argv);
908	}
909	if (sp->se_window) {
910		free(sp->se_window);
911		free(sp->se_window_argv);
912	}
913	free(sp);
914}
915
916/*
917 * Allocate a new session descriptor.
918 */
919session_t *
920new_session(sprev, session_index, typ)
921	session_t *sprev;
922	int session_index;
923	register struct ttyent *typ;
924{
925	register session_t *sp;
926
927	if ((typ->ty_status & TTY_ON) == 0 ||
928	    typ->ty_name == 0 ||
929	    typ->ty_getty == 0)
930		return 0;
931
932	sp = (session_t *) malloc(sizeof (session_t));
933	memset(sp, 0, sizeof *sp);
934
935	sp->se_flags = SE_PRESENT;
936	sp->se_index = session_index;
937
938	sp->se_device = malloc(sizeof(_PATH_DEV) + strlen(typ->ty_name));
939	(void) sprintf(sp->se_device, "%s%s", _PATH_DEV, typ->ty_name);
940
941	if (setupargv(sp, typ) == 0) {
942		free_session(sp);
943		return (0);
944	}
945
946	sp->se_next = 0;
947	if (sprev == 0) {
948		sessions = sp;
949		sp->se_prev = 0;
950	} else {
951		sprev->se_next = sp;
952		sp->se_prev = sprev;
953	}
954
955	return sp;
956}
957
958/*
959 * Calculate getty and if useful window argv vectors.
960 */
961int
962setupargv(sp, typ)
963	session_t *sp;
964	struct ttyent *typ;
965{
966
967	if (sp->se_getty) {
968		free(sp->se_getty);
969		free(sp->se_getty_argv);
970	}
971	sp->se_getty = malloc(strlen(typ->ty_getty) + strlen(typ->ty_name) + 2);
972	(void) sprintf(sp->se_getty, "%s %s", typ->ty_getty, typ->ty_name);
973	sp->se_getty_argv = construct_argv(sp->se_getty);
974	if (sp->se_getty_argv == 0) {
975		warning("can't parse getty for port %s", sp->se_device);
976		free(sp->se_getty);
977		sp->se_getty = 0;
978		return (0);
979	}
980	if (typ->ty_window) {
981		if (sp->se_window)
982			free(sp->se_window);
983		sp->se_window = strdup(typ->ty_window);
984		sp->se_window_argv = construct_argv(sp->se_window);
985		if (sp->se_window_argv == 0) {
986			warning("can't parse window for port %s",
987				sp->se_device);
988			free(sp->se_window);
989			sp->se_window = 0;
990			return (0);
991		}
992	}
993	return (1);
994}
995
996/*
997 * Walk the list of ttys and create sessions for each active line.
998 */
999state_func_t
1000read_ttys()
1001{
1002	int session_index = 0;
1003	register session_t *sp, *snext;
1004	register struct ttyent *typ;
1005
1006	/*
1007	 * Destroy any previous session state.
1008	 * There shouldn't be any, but just in case...
1009	 */
1010	for (sp = sessions; sp; sp = snext) {
1011		if (sp->se_process)
1012			clear_session_logs(sp);
1013		snext = sp->se_next;
1014		free_session(sp);
1015	}
1016	sessions = 0;
1017	if (start_session_db())
1018		return (state_func_t) single_user;
1019
1020	/*
1021	 * Allocate a session entry for each active port.
1022	 * Note that sp starts at 0.
1023	 */
1024	while ((typ = getttyent()))
1025		if ((snext = new_session(sp, ++session_index, typ)))
1026			sp = snext;
1027
1028	endttyent();
1029
1030	return (state_func_t) multi_user;
1031}
1032
1033/*
1034 * Start a window system running.
1035 */
1036void
1037start_window_system(sp)
1038	session_t *sp;
1039{
1040	pid_t pid;
1041	sigset_t mask;
1042
1043	if ((pid = fork()) == -1) {
1044		emergency("can't fork for window system on port %s: %m",
1045			sp->se_device);
1046		/* hope that getty fails and we can try again */
1047		return;
1048	}
1049
1050	if (pid)
1051		return;
1052
1053	sigemptyset(&mask);
1054	sigprocmask(SIG_SETMASK, &mask, NULL);
1055
1056	if (setsid() < 0)
1057		emergency("setsid failed (window) %m");
1058
1059	execv(sp->se_window_argv[0], sp->se_window_argv);
1060	stall("can't exec window system '%s' for port %s: %m",
1061		sp->se_window_argv[0], sp->se_device);
1062	_exit(1);
1063}
1064
1065/*
1066 * Start a login session running.
1067 * For first open, man-handle tty directly to determine if it
1068 * really exists. It is not efficient to spawn gettys on devices
1069 * that do not exist.
1070 */
1071pid_t
1072start_getty(sp)
1073	session_t *sp;
1074{
1075	pid_t pid;
1076	sigset_t mask;
1077	time_t current_time = time(NULL);
1078	int p[2], new = 1;
1079
1080	if (sp->se_flags & SE_DEVEXISTS)
1081		new = 0;
1082
1083	if (new) {
1084		if (pipe(p) == -1)
1085			return -1;
1086	}
1087
1088	/*
1089	 * fork(), not vfork() -- we can't afford to block.
1090	 */
1091	if ((pid = fork()) == -1) {
1092		emergency("can't fork for getty on port %s: %m", sp->se_device);
1093		return -1;
1094	}
1095
1096	if (pid) {
1097		if (new) {
1098			char c;
1099
1100			close(p[1]);
1101			if (read(p[0], &c, 1) != 1) {
1102				close(p[0]);
1103				return -1;
1104			}
1105			close(p[0]);
1106			if (c == '1')
1107				sp->se_flags |= SE_DEVEXISTS;
1108			else
1109				sp->se_flags |= SE_SHUTDOWN;
1110		}
1111		return pid;
1112	}
1113	if (new) {
1114		int fd;
1115
1116		close(p[0]);
1117		fd = open(sp->se_device, O_RDONLY | O_NONBLOCK, 0666);
1118		if (fd == -1 && (errno == ENXIO || errno == ENOENT ||
1119		    errno == EISDIR)) {
1120			(void)write(p[1], "0", 1);
1121			close(p[1]);
1122			_exit(1);
1123		}
1124		(void)write(p[1], "1", 1);
1125		close(p[1]);
1126		close(fd);
1127		sleep(1);
1128	}
1129
1130	if (current_time > sp->se_started &&
1131	    current_time - sp->se_started < GETTY_SPACING) {
1132		warning("getty repeating too quickly on port %s, sleeping",
1133		        sp->se_device);
1134		sleep((unsigned) GETTY_SLEEP);
1135	}
1136
1137	if (sp->se_window) {
1138		start_window_system(sp);
1139		sleep(WINDOW_WAIT);
1140	}
1141
1142	sigemptyset(&mask);
1143	sigprocmask(SIG_SETMASK, &mask, NULL);
1144
1145	execv(sp->se_getty_argv[0], sp->se_getty_argv);
1146	stall("can't exec getty '%s' for port %s: %m",
1147		sp->se_getty_argv[0], sp->se_device);
1148	_exit(1);
1149}
1150
1151/*
1152 * Collect exit status for a child.
1153 * If an exiting login, start a new login running.
1154 */
1155void
1156#ifdef __STDC__
1157collect_child(pid_t pid)
1158#else
1159collect_child(pid)
1160	pid_t pid;
1161#endif
1162{
1163	register session_t *sp, *sprev, *snext;
1164
1165	if (! sessions)
1166		return;
1167
1168	if (! (sp = find_session(pid)))
1169		return;
1170
1171	clear_session_logs(sp);
1172	login_fbtab(sp->se_device + sizeof(_PATH_DEV) - 1, 0, 0);
1173	del_session(sp);
1174	sp->se_process = 0;
1175
1176	if (sp->se_flags & SE_SHUTDOWN) {
1177		if ((sprev = sp->se_prev))
1178			sprev->se_next = sp->se_next;
1179		else
1180			sessions = sp->se_next;
1181		if ((snext = sp->se_next))
1182			snext->se_prev = sp->se_prev;
1183		free_session(sp);
1184		return;
1185	}
1186
1187	if ((pid = start_getty(sp)) == -1) {
1188		/* serious trouble */
1189		requested_transition = clean_ttys;
1190		return;
1191	}
1192
1193	sp->se_process = pid;
1194	sp->se_started = time(NULL);
1195	add_session(sp);
1196}
1197
1198/*
1199 * Catch a signal and request a state transition.
1200 */
1201void
1202transition_handler(sig)
1203	int sig;
1204{
1205
1206	switch (sig) {
1207	case SIGHUP:
1208		requested_transition = clean_ttys;
1209		break;
1210	case SIGTERM:
1211		requested_transition = death;
1212		break;
1213	case SIGUSR1:
1214		requested_transition = nice_death;
1215		break;
1216	case SIGTSTP:
1217		requested_transition = catatonia;
1218		break;
1219	default:
1220		requested_transition = 0;
1221		break;
1222	}
1223}
1224
1225/*
1226 * Take the system multiuser.
1227 */
1228state_func_t
1229multi_user()
1230{
1231	pid_t pid;
1232	register session_t *sp;
1233
1234	requested_transition = 0;
1235
1236	/*
1237	 * If the administrator has not set the security level to -1
1238	 * to indicate that the kernel should not run multiuser in secure
1239	 * mode, and the run script has not set a higher level of security
1240	 * than level 1, then put the kernel into secure mode.
1241	 */
1242	if (getsecuritylevel() == 0)
1243		setsecuritylevel(1);
1244
1245	for (sp = sessions; sp; sp = sp->se_next) {
1246		if (sp->se_process)
1247			continue;
1248		if ((pid = start_getty(sp)) == -1) {
1249			/* serious trouble */
1250			requested_transition = clean_ttys;
1251			break;
1252		}
1253		sp->se_process = pid;
1254		sp->se_started = time(NULL);
1255		add_session(sp);
1256	}
1257
1258	while (!requested_transition)
1259		if ((pid = waitpid(-1, NULL, 0)) != -1)
1260			collect_child(pid);
1261
1262	return (state_func_t) requested_transition;
1263}
1264
1265/*
1266 * This is an n-squared algorithm.  We hope it isn't run often...
1267 */
1268state_func_t
1269clean_ttys()
1270{
1271	register session_t *sp, *sprev;
1272	register struct ttyent *typ;
1273	register int session_index = 0;
1274	register int devlen;
1275
1276	for (sp = sessions; sp; sp = sp->se_next)
1277		sp->se_flags &= ~SE_PRESENT;
1278
1279	devlen = sizeof(_PATH_DEV) - 1;
1280	while ((typ = getttyent())) {
1281		++session_index;
1282
1283		for (sprev = 0, sp = sessions; sp; sprev = sp, sp = sp->se_next)
1284			if (strcmp(typ->ty_name, sp->se_device + devlen) == 0)
1285				break;
1286
1287		if (sp) {
1288			sp->se_flags |= SE_PRESENT;
1289			if (sp->se_index != session_index) {
1290				warning("port %s changed utmp index from %d to %d",
1291				       sp->se_device, sp->se_index,
1292				       session_index);
1293				sp->se_index = session_index;
1294			}
1295			if ((typ->ty_status & TTY_ON) == 0 ||
1296			    typ->ty_getty == 0) {
1297				sp->se_flags |= SE_SHUTDOWN;
1298				kill(sp->se_process, SIGHUP);
1299				continue;
1300			}
1301			sp->se_flags &= ~SE_SHUTDOWN;
1302			if (setupargv(sp, typ) == 0) {
1303				warning("can't parse getty for port %s",
1304					sp->se_device);
1305				sp->se_flags |= SE_SHUTDOWN;
1306				kill(sp->se_process, SIGHUP);
1307			}
1308			continue;
1309		}
1310
1311		new_session(sprev, session_index, typ);
1312	}
1313
1314	endttyent();
1315
1316	for (sp = sessions; sp; sp = sp->se_next)
1317		if ((sp->se_flags & SE_PRESENT) == 0) {
1318			sp->se_flags |= SE_SHUTDOWN;
1319			kill(sp->se_process, SIGHUP);
1320		}
1321
1322	return (state_func_t) multi_user;
1323}
1324
1325/*
1326 * Block further logins.
1327 */
1328state_func_t
1329catatonia()
1330{
1331	register session_t *sp;
1332
1333	for (sp = sessions; sp; sp = sp->se_next)
1334		sp->se_flags |= SE_SHUTDOWN;
1335
1336	return (state_func_t) multi_user;
1337}
1338
1339/*
1340 * Note SIGALRM.
1341 */
1342void
1343alrm_handler(sig)
1344	int sig;
1345{
1346	clang = 1;
1347}
1348
1349/*
1350 * Bring the system down to single user nicely, after run the shutdown script.
1351 */
1352state_func_t
1353nice_death()
1354{
1355	register session_t *sp;
1356	register int i;
1357	pid_t pid;
1358	static const int death_sigs[3] = { SIGHUP, SIGTERM, SIGKILL };
1359	int howto = RB_HALT;
1360	int status;
1361
1362	for (sp = sessions; sp; sp = sp->se_next) {
1363		sp->se_flags &= ~SE_PRESENT;
1364		sp->se_flags |= SE_SHUTDOWN;
1365		kill(sp->se_process, SIGHUP);
1366	}
1367
1368	/* NB: should send a message to the session logger to avoid blocking. */
1369	logwtmp("~", "shutdown", "");
1370
1371	if (access(_PATH_RUNCOM, R_OK) != -1) {
1372		pid_t pid;
1373		struct sigaction sa;
1374
1375		switch ((pid = fork())) {
1376		case -1:
1377			break;
1378		case 0:
1379
1380			memset(&sa, 0, sizeof sa);
1381			sigemptyset(&sa.sa_mask);
1382			sa.sa_flags = 0;
1383			sa.sa_handler = SIG_IGN;
1384			(void) sigaction(SIGTSTP, &sa, NULL);
1385			(void) sigaction(SIGHUP, &sa, NULL);
1386
1387			setctty(_PATH_CONSOLE);
1388
1389			sigprocmask(SIG_SETMASK, &sa.sa_mask, NULL);
1390
1391			execl(_PATH_BSHELL, "sh", _PATH_RUNCOM, "shutdown",
1392			    NULL);
1393			stall("can't exec %s for %s %s: %m", _PATH_BSHELL,
1394			    _PATH_RUNCOM, "shutdown");
1395			_exit(1);
1396		default:
1397			waitpid(pid, &status, 0);
1398			if (WIFEXITED(status) && WEXITSTATUS(status) == 2)
1399				howto |= RB_POWERDOWN;
1400		}
1401	}
1402
1403	for (i = 0; i < 3; ++i) {
1404		if (kill(-1, death_sigs[i]) == -1 && errno == ESRCH)
1405			goto die;
1406
1407		clang = 0;
1408		alarm(DEATH_WATCH);
1409		do
1410			if ((pid = waitpid(-1, NULL, 0)) != -1)
1411				collect_child(pid);
1412		while (clang == 0 && errno != ECHILD);
1413
1414		if (errno == ECHILD)
1415			goto die;
1416	}
1417
1418	warning("some processes would not die; ps axl advised");
1419
1420die:
1421	reboot(howto);
1422
1423	/* ... and if that fails.. oh well */
1424	return (state_func_t) single_user;
1425}
1426
1427/*
1428 * Bring the system down to single user.
1429 */
1430state_func_t
1431death()
1432{
1433	register session_t *sp;
1434	register int i;
1435	pid_t pid;
1436	static const int death_sigs[3] = { SIGHUP, SIGTERM, SIGKILL };
1437
1438	for (sp = sessions; sp; sp = sp->se_next)
1439		sp->se_flags |= SE_SHUTDOWN;
1440
1441	/* NB: should send a message to the session logger to avoid blocking. */
1442	logwtmp("~", "shutdown", "");
1443
1444	for (i = 0; i < 3; ++i) {
1445		if (kill(-1, death_sigs[i]) == -1 && errno == ESRCH)
1446			return (state_func_t) single_user;
1447
1448		clang = 0;
1449		alarm(DEATH_WATCH);
1450		do
1451			if ((pid = waitpid(-1, NULL, 0)) != -1)
1452				collect_child(pid);
1453		while (clang == 0 && errno != ECHILD);
1454
1455		if (errno == ECHILD)
1456			return (state_func_t) single_user;
1457	}
1458
1459	warning("some processes would not die; ps axl advised");
1460
1461	return (state_func_t) single_user;
1462}
1463