init.c revision 1.59 
1/*	$OpenBSD: init.c,v 1.59 2016/05/10 21:54:59 bluhm Exp $	*/
2/*	$NetBSD: init.c,v 1.22 1996/05/15 23:29:33 jtc Exp $	*/
3
4/*-
5 * Copyright (c) 1991, 1993
6 *	The Regents of the University of California.  All rights reserved.
7 *
8 * This code is derived from software contributed to Berkeley by
9 * Donn Seeley at Berkeley Software Design, Inc.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 *    notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 *    notice, this list of conditions and the following disclaimer in the
18 *    documentation and/or other materials provided with the distribution.
19 * 3. Neither the name of the University nor the names of its contributors
20 *    may be used to endorse or promote products derived from this software
21 *    without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36#include <sys/types.h>
37#include <sys/sysctl.h>
38#include <sys/wait.h>
39#include <sys/reboot.h>
40#include <machine/cpu.h>
41
42#include <db.h>
43#include <err.h>
44#include <errno.h>
45#include <fcntl.h>
46#include <signal.h>
47#include <stdarg.h>
48#include <stdio.h>
49#include <stdlib.h>
50#include <string.h>
51#include <syslog.h>
52#include <time.h>
53#include <ttyent.h>
54#include <unistd.h>
55#include <util.h>
56
57#ifdef SECURE
58#include <pwd.h>
59#endif
60
61#ifdef LOGIN_CAP
62#include <login_cap.h>
63#endif
64
65#include "pathnames.h"
66
67/*
68 * Sleep times; used to prevent thrashing.
69 */
70#define	GETTY_SPACING		 5	/* N secs minimum getty spacing */
71#define	GETTY_SLEEP		30	/* sleep N secs after spacing problem */
72#define	WINDOW_WAIT		 3	/* wait N secs after starting window */
73#define	STALL_TIMEOUT		30	/* wait N secs after warning */
74#define	DEATH_WATCH		10	/* wait N secs for procs to die */
75
76/*
77 * User-based resource limits.
78 */
79#define RESOURCE_RC		"daemon"
80#define RESOURCE_WINDOW		"default"
81#define RESOURCE_GETTY		"default"
82
83#ifndef DEFAULT_STATE
84#define DEFAULT_STATE		runcom
85#endif
86
87void handle(sig_t, ...);
88void delset(sigset_t *, ...);
89
90void stall(char *, ...);
91void warning(char *, ...);
92void emergency(char *, ...);
93void disaster(int);
94void badsys(int);
95
96typedef enum {
97	invalid_state,
98	single_user,
99	runcom,
100	read_ttys,
101	multi_user,
102	clean_ttys,
103	catatonia,
104	death,
105	do_reboot,
106	hard_death,
107	nice_death
108} state_t;
109typedef state_t (*state_func_t)(void);
110
111state_t f_single_user(void);
112state_t f_runcom(void);
113state_t f_read_ttys(void);
114state_t f_multi_user(void);
115state_t f_clean_ttys(void);
116state_t f_catatonia(void);
117state_t f_death(void);
118state_t f_do_reboot(void);
119state_t f_hard_death(void);
120state_t f_nice_death(void);
121
122state_func_t state_funcs[] = {
123	NULL,
124	f_single_user,
125	f_runcom,
126	f_read_ttys,
127	f_multi_user,
128	f_clean_ttys,
129	f_catatonia,
130	f_death,
131	f_do_reboot,
132	f_hard_death,
133	f_nice_death
134};
135
136enum { AUTOBOOT, FASTBOOT } runcom_mode = AUTOBOOT;
137
138void transition(state_t);
139volatile sig_atomic_t requested_transition = DEFAULT_STATE;
140
141void setctty(char *);
142
143typedef struct init_session {
144	int	se_index;		/* index of entry in ttys file */
145	pid_t	se_process;		/* controlling process */
146	time_t	se_started;		/* used to avoid thrashing */
147	int	se_flags;		/* status of session */
148#define	SE_SHUTDOWN	0x1		/* session won't be restarted */
149#define	SE_PRESENT	0x2		/* session is in /etc/ttys */
150#define	SE_DEVEXISTS	0x4		/* open does not result in ENODEV */
151	char	*se_device;		/* filename of port */
152	char	*se_getty;		/* what to run on that port */
153	char	**se_getty_argv;	/* pre-parsed argument array */
154	char	*se_window;		/* window system (started only once) */
155	char	**se_window_argv;	/* pre-parsed argument array */
156	struct	init_session *se_prev;
157	struct	init_session *se_next;
158} session_t;
159
160void free_session(session_t *);
161session_t *new_session(session_t *, int, struct ttyent *);
162session_t *sessions;
163
164char **construct_argv(char *);
165void start_window_system(session_t *);
166void collect_child(pid_t);
167pid_t start_getty(session_t *);
168void transition_handler(int);
169void alrm_handler(int);
170void setsecuritylevel(int);
171int getsecuritylevel(void);
172int setupargv(session_t *, struct ttyent *);
173int clang;
174
175#ifdef LOGIN_CAP
176void setprocresources(char *);
177#else
178#define setprocresources(p)
179#endif
180
181void clear_session_logs(session_t *);
182
183int start_session_db(void);
184void add_session(session_t *);
185void del_session(session_t *);
186session_t *find_session(pid_t);
187DB *session_db;
188
189/*
190 * The mother of all processes.
191 */
192int
193main(int argc, char *argv[])
194{
195	int c, fd;
196	struct sigaction sa;
197	sigset_t mask;
198
199	/* Dispose of random users. */
200	if (getuid() != 0) {
201		(void)fprintf(stderr, "init: %s\n", strerror(EPERM));
202		exit (1);
203	}
204
205	/* System V users like to reexec init. */
206	if (getpid() != 1) {
207		(void)fprintf(stderr, "init: already running\n");
208		exit (1);
209	}
210
211	/*
212	 * Paranoia.
213	 */
214	if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
215		(void)dup2(fd, STDIN_FILENO);
216		(void)dup2(fd, STDOUT_FILENO);
217		(void)dup2(fd, STDERR_FILENO);
218		if (fd > 2)
219			(void)close(fd);
220	}
221
222	/*
223	 * Note that this does NOT open a file...
224	 * Does 'init' deserve its own facility number?
225	 */
226	openlog("init", LOG_CONS|LOG_ODELAY, LOG_AUTH);
227
228	/*
229	 * Create an initial session.
230	 */
231	if (setsid() < 0)
232		warning("initial setsid() failed: %m");
233
234	/*
235	 * Establish an initial user so that programs running
236	 * single user do not freak out and die (like passwd).
237	 */
238	if (setlogin("root") < 0)
239		warning("setlogin() failed: %m");
240
241	/*
242	 * This code assumes that we always get arguments through flags,
243	 * never through bits set in some random machine register.
244	 */
245	while ((c = getopt(argc, argv, "sf")) != -1)
246		switch (c) {
247		case 's':
248			requested_transition = single_user;
249			break;
250		case 'f':
251			runcom_mode = FASTBOOT;
252			break;
253		default:
254			warning("unrecognized flag '-%c'", c);
255			break;
256		}
257
258	if (optind != argc)
259		warning("ignoring excess arguments");
260
261	/*
262	 * We catch or block signals rather than ignore them,
263	 * so that they get reset on exec.
264	 */
265	handle(badsys, SIGSYS, 0);
266	handle(disaster, SIGABRT, SIGFPE, SIGILL, SIGSEGV,
267	    SIGBUS, SIGXCPU, SIGXFSZ, 0);
268	handle(transition_handler, SIGHUP, SIGINT, SIGTERM, SIGTSTP,
269            SIGUSR1, SIGUSR2, 0);
270	handle(alrm_handler, SIGALRM, 0);
271	sigfillset(&mask);
272	delset(&mask, SIGABRT, SIGFPE, SIGILL, SIGSEGV, SIGBUS, SIGSYS,
273	    SIGXCPU, SIGXFSZ, SIGHUP, SIGINT, SIGTERM, SIGUSR1, SIGUSR2,
274	    SIGTSTP, SIGALRM, 0);
275	sigprocmask(SIG_SETMASK, &mask, NULL);
276	memset(&sa, 0, sizeof sa);
277	sigemptyset(&sa.sa_mask);
278	sa.sa_flags = 0;
279	sa.sa_handler = SIG_IGN;
280	(void) sigaction(SIGTTIN, &sa, NULL);
281	(void) sigaction(SIGTTOU, &sa, NULL);
282
283	/*
284	 * Start the state machine.
285	 */
286	transition(requested_transition);
287
288	/*
289	 * Should never reach here.
290	 */
291	exit(1);
292}
293
294/*
295 * Associate a function with a signal handler.
296 */
297void
298handle(sig_t handler, ...)
299{
300	int sig;
301	struct sigaction sa;
302	sigset_t mask_everything;
303	va_list ap;
304
305	va_start(ap, handler);
306
307	memset(&sa, 0, sizeof sa);
308	sa.sa_handler = handler;
309	sigfillset(&mask_everything);
310
311	while ((sig = va_arg(ap, int))) {
312		sa.sa_mask = mask_everything;
313		/* XXX SA_RESTART? */
314		sa.sa_flags = sig == SIGCHLD ? SA_NOCLDSTOP : 0;
315		sigaction(sig, &sa, NULL);
316	}
317	va_end(ap);
318}
319
320/*
321 * Delete a set of signals from a mask.
322 */
323void
324delset(sigset_t *maskp, ...)
325{
326	int sig;
327	va_list ap;
328
329	va_start(ap, maskp);
330	while ((sig = va_arg(ap, int)))
331		sigdelset(maskp, sig);
332	va_end(ap);
333}
334
335/*
336 * Log a message and sleep for a while (to give someone an opportunity
337 * to read it and to save log or hardcopy output if the problem is chronic).
338 * NB: should send a message to the session logger to avoid blocking.
339 */
340void
341stall(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	sleep(STALL_TIMEOUT);
350}
351
352/*
353 * Like stall(), but doesn't sleep.
354 * If cpp had variadic macros, the two functions could be #defines for another.
355 * NB: should send a message to the session logger to avoid blocking.
356 */
357void
358warning(char *message, ...)
359{
360	va_list ap;
361
362	va_start(ap, message);
363	vsyslog(LOG_ALERT, message, ap);
364	va_end(ap);
365	closelog();
366}
367
368/*
369 * Log an emergency message.
370 * NB: should send a message to the session logger to avoid blocking.
371 */
372void
373emergency(char *message, ...)
374{
375	struct syslog_data sdata = SYSLOG_DATA_INIT;
376	va_list ap;
377
378	va_start(ap, message);
379	vsyslog_r(LOG_EMERG, &sdata, message, ap);
380	va_end(ap);
381}
382
383/*
384 * Catch a SIGSYS signal.
385 *
386 * These may arise if a system does not support sysctl.
387 * We tolerate up to 25 of these, then throw in the towel.
388 */
389void
390badsys(int sig)
391{
392	static int badcount = 0;
393
394	if (badcount++ < 25)
395		return;
396	disaster(sig);
397}
398
399/*
400 * Catch an unexpected signal.
401 */
402void
403disaster(int sig)
404{
405	emergency("fatal signal: %s", strsignal(sig));
406
407	sleep(STALL_TIMEOUT);
408	_exit(sig);		/* reboot */
409}
410
411/*
412 * Get the security level of the kernel.
413 */
414int
415getsecuritylevel(void)
416{
417#ifdef KERN_SECURELVL
418	int name[2], curlevel;
419	size_t len;
420
421	name[0] = CTL_KERN;
422	name[1] = KERN_SECURELVL;
423	len = sizeof curlevel;
424	if (sysctl(name, 2, &curlevel, &len, NULL, 0) == -1) {
425		emergency("cannot get kernel security level: %s",
426		    strerror(errno));
427		return (-1);
428	}
429	return (curlevel);
430#else
431	return (-1);
432#endif
433}
434
435/*
436 * Set the security level of the kernel.
437 */
438void
439setsecuritylevel(int newlevel)
440{
441#ifdef KERN_SECURELVL
442	int name[2], curlevel;
443
444	curlevel = getsecuritylevel();
445	if (newlevel == curlevel)
446		return;
447	name[0] = CTL_KERN;
448	name[1] = KERN_SECURELVL;
449	if (sysctl(name, 2, NULL, NULL, &newlevel, sizeof newlevel) == -1) {
450		emergency(
451		    "cannot change kernel security level from %d to %d: %s",
452		    curlevel, newlevel, strerror(errno));
453		return;
454	}
455#ifdef SECURE
456	warning("kernel security level changed from %d to %d",
457	    curlevel, newlevel);
458#endif
459#endif
460}
461
462/*
463 * Change states in the finite state machine.
464 * The initial state is passed as an argument.
465 */
466void
467transition(state_t s)
468{
469	for (;;)
470		s = (*state_funcs[s])();
471}
472
473/*
474 * Close out the accounting files for a login session.
475 * NB: should send a message to the session logger to avoid blocking.
476 */
477void
478clear_session_logs(session_t *sp)
479{
480	char *line = sp->se_device + sizeof(_PATH_DEV) - 1;
481
482	if (logout(line))
483		logwtmp(line, "", "");
484}
485
486/*
487 * Start a session and allocate a controlling terminal.
488 * Only called by children of init after forking.
489 */
490void
491setctty(char *name)
492{
493	int fd;
494
495	(void) revoke(name);
496	sleep(2);			/* leave DTR low */
497	if ((fd = open(name, O_RDWR)) == -1) {
498		stall("can't open %s: %m", name);
499		_exit(1);
500	}
501	if (login_tty(fd) == -1) {
502		stall("can't get %s for controlling terminal: %m", name);
503		_exit(1);
504	}
505}
506
507/*
508 * Bring the system up single user.
509 */
510state_t
511f_single_user(void)
512{
513	pid_t pid, wpid;
514	int status;
515	sigset_t mask;
516	char shell[PATH_MAX];		/* Allocate space here */
517	char name[PATH_MAX];		/* Name (argv[0]) of shell */
518	char *argv[2];
519#ifdef SECURE
520	struct ttyent *typ;
521	struct passwd *pp;
522	static const char banner[] =
523		"Enter root password, or ^D to go multi-user\n";
524	char *clear;
525#endif
526
527	/* Init shell and name */
528	strlcpy(shell, _PATH_BSHELL, sizeof shell);
529	strlcpy(name, "-sh", sizeof name);
530
531	/*
532	 * If the kernel is in secure mode, downgrade it to insecure mode.
533	 */
534	if (getsecuritylevel() > 0)
535		setsecuritylevel(0);
536
537	if ((pid = fork()) == 0) {
538		/*
539		 * Start the single user session.
540		 */
541		setctty(_PATH_CONSOLE);
542
543#ifdef SECURE
544		/*
545		 * Check the root password.
546		 * We don't care if the console is 'on' by default;
547		 * it's the only tty that can be 'off' and 'secure'.
548		 */
549		typ = getttynam("console");
550		pp = getpwnam_shadow("root");
551		if (typ && (typ->ty_status & TTY_SECURE) == 0 && pp &&
552		    *pp->pw_passwd) {
553			write(STDERR_FILENO, banner, sizeof banner - 1);
554			for (;;) {
555				int ok = 0;
556				clear = getpass("Password:");
557				if (clear == NULL || *clear == '\0')
558					_exit(0);
559				if (crypt_checkpass(clear, pp->pw_passwd) == 0)
560					ok = 1;
561				memset(clear, 0, strlen(clear));
562				if (ok)
563					break;
564				warning("single-user login failed\n");
565			}
566		}
567		endttyent();
568		endpwent();
569#endif /* SECURE */
570
571#ifdef DEBUGSHELL
572		{
573			char altshell[128], *cp = altshell;
574			int num;
575
576#define	SHREQUEST \
577	"Enter pathname of shell or RETURN for sh: "
578
579			(void)write(STDERR_FILENO,
580			    SHREQUEST, sizeof(SHREQUEST) - 1);
581			while ((num = read(STDIN_FILENO, cp, 1)) != -1 &&
582			    num != 0 && *cp != '\n' && cp < &altshell[127])
583				cp++;
584			*cp = '\0';
585
586			/* Copy in alternate shell */
587			if (altshell[0] != '\0'){
588				char *p;
589
590				/* Binary to exec */
591				strlcpy(shell, altshell, sizeof shell);
592
593				/* argv[0] */
594				p = strrchr(altshell, '/');
595				if(p == NULL) p = altshell;
596				else p++;
597
598				name[0] = '-';
599				strlcpy(&name[1], p, sizeof name -1);
600			}
601		}
602#endif /* DEBUGSHELL */
603
604		/*
605		 * Unblock signals.
606		 * We catch all the interesting ones,
607		 * and those are reset to SIG_DFL on exec.
608		 */
609		sigemptyset(&mask);
610		sigprocmask(SIG_SETMASK, &mask, NULL);
611
612		/*
613		 * Fire off a shell.
614		 * If the default one doesn't work, try the Bourne shell.
615		 */
616		argv[0] = name;
617		argv[1] = NULL;
618		setenv("PATH", _PATH_STDPATH, 1);
619		execv(shell, argv);
620		emergency("can't exec %s for single user: %m", shell);
621
622		argv[0] = "-sh";
623		argv[1] = NULL;
624		execv(_PATH_BSHELL, argv);
625		emergency("can't exec %s for single user: %m", _PATH_BSHELL);
626		sleep(STALL_TIMEOUT);
627		_exit(1);
628	}
629
630	if (pid == -1) {
631		/*
632		 * We are seriously hosed.  Do our best.
633		 */
634		emergency("can't fork single-user shell, trying again");
635		while (waitpid(-1, NULL, WNOHANG) > 0)
636			continue;
637		return single_user;
638	}
639
640	requested_transition = 0;
641	do {
642		if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1)
643			collect_child(wpid);
644		if (wpid == -1) {
645			if (errno == EINTR)
646				continue;
647			warning("wait for single-user shell failed: %m; restarting");
648			return single_user;
649		}
650		if (wpid == pid && WIFSTOPPED(status)) {
651			warning("init: shell stopped, restarting\n");
652			kill(pid, SIGCONT);
653			wpid = -1;
654		}
655	} while (wpid != pid && !requested_transition);
656
657	if (requested_transition)
658		return requested_transition;
659
660	if (!WIFEXITED(status)) {
661		if (WTERMSIG(status) == SIGKILL) {
662			/*
663			 *  reboot(8) killed shell?
664			 */
665			warning("single user shell terminated.");
666			sleep(STALL_TIMEOUT);
667			_exit(0);
668		} else {
669			warning("single user shell terminated, restarting");
670			return single_user;
671		}
672	}
673
674	runcom_mode = FASTBOOT;
675	return runcom;
676}
677
678/*
679 * Run the system startup script.
680 */
681state_t
682f_runcom(void)
683{
684	pid_t pid, wpid;
685	int status;
686	char *argv[4];
687	struct sigaction sa;
688
689	if ((pid = fork()) == 0) {
690		memset(&sa, 0, sizeof sa);
691		sigemptyset(&sa.sa_mask);
692		sa.sa_flags = 0;
693		sa.sa_handler = SIG_IGN;
694		(void) sigaction(SIGTSTP, &sa, NULL);
695		(void) sigaction(SIGHUP, &sa, NULL);
696
697		setctty(_PATH_CONSOLE);
698
699		argv[0] = "sh";
700		argv[1] = _PATH_RUNCOM;
701		argv[2] = runcom_mode == AUTOBOOT ? "autoboot" : NULL;
702		argv[3] = NULL;
703
704		sigprocmask(SIG_SETMASK, &sa.sa_mask, NULL);
705
706		setprocresources(RESOURCE_RC);
707
708		execv(_PATH_BSHELL, argv);
709		stall("can't exec %s for %s: %m", _PATH_BSHELL, _PATH_RUNCOM);
710		_exit(1);	/* force single user mode */
711	}
712
713	if (pid == -1) {
714		emergency("can't fork for %s on %s: %m",
715			_PATH_BSHELL, _PATH_RUNCOM);
716		while (waitpid(-1, NULL, WNOHANG) > 0)
717			continue;
718		sleep(STALL_TIMEOUT);
719		return single_user;
720	}
721
722	/*
723	 * Copied from single_user().  This is a bit paranoid.
724	 */
725	do {
726		if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1)
727			collect_child(wpid);
728		if (wpid == -1) {
729			if (errno == EINTR)
730				continue;
731			warning("wait for %s on %s failed: %m; going to single user mode",
732			    _PATH_BSHELL, _PATH_RUNCOM);
733			return single_user;
734		}
735		if (wpid == pid && WIFSTOPPED(status)) {
736			warning("init: %s on %s stopped, restarting\n",
737			    _PATH_BSHELL, _PATH_RUNCOM);
738			kill(pid, SIGCONT);
739			wpid = -1;
740		}
741	} while (wpid != pid);
742
743	if (WIFSIGNALED(status) && WTERMSIG(status) == SIGTERM &&
744	    requested_transition == catatonia) {
745		/* /etc/rc executed /sbin/reboot; wait for the end quietly */
746		sigset_t s;
747
748		sigfillset(&s);
749		for (;;)
750			sigsuspend(&s);
751	}
752
753	if (!WIFEXITED(status)) {
754		warning("%s on %s terminated abnormally, going to single user mode",
755		    _PATH_BSHELL, _PATH_RUNCOM);
756		return single_user;
757	}
758
759	if (WEXITSTATUS(status))
760		return single_user;
761
762	runcom_mode = AUTOBOOT;		/* the default */
763	/* NB: should send a message to the session logger to avoid blocking. */
764	logwtmp("~", "reboot", "");
765	return read_ttys;
766}
767
768/*
769 * Open the session database.
770 *
771 * NB: We could pass in the size here; is it necessary?
772 */
773int
774start_session_db(void)
775{
776	if (session_db && (*session_db->close)(session_db))
777		emergency("session database close: %s", strerror(errno));
778	if ((session_db = dbopen(NULL, O_RDWR, 0, DB_HASH, NULL)) == 0) {
779		emergency("session database open: %s", strerror(errno));
780		return (1);
781	}
782	return (0);
783}
784
785/*
786 * Add a new login session.
787 */
788void
789add_session(session_t *sp)
790{
791	DBT key;
792	DBT data;
793
794	key.data = &sp->se_process;
795	key.size = sizeof sp->se_process;
796	data.data = &sp;
797	data.size = sizeof sp;
798
799	if ((*session_db->put)(session_db, &key, &data, 0))
800		emergency("insert %d: %s", sp->se_process, strerror(errno));
801}
802
803/*
804 * Delete an old login session.
805 */
806void
807del_session(session_t *sp)
808{
809	DBT key;
810
811	key.data = &sp->se_process;
812	key.size = sizeof sp->se_process;
813
814	if ((*session_db->del)(session_db, &key, 0))
815		emergency("delete %d: %s", sp->se_process, strerror(errno));
816}
817
818/*
819 * Look up a login session by pid.
820 */
821session_t *
822find_session(pid_t pid)
823{
824	DBT key;
825	DBT data;
826	session_t *ret;
827
828	key.data = &pid;
829	key.size = sizeof pid;
830	if ((*session_db->get)(session_db, &key, &data, 0) != 0)
831		return (0);
832	memcpy(&ret, data.data, sizeof(ret));
833	return (ret);
834}
835
836/*
837 * Construct an argument vector from a command line.
838 */
839char **
840construct_argv(char *command)
841{
842	int argc = 0;
843	char **argv = calloc((strlen(command) + 1) / 2 + 1, sizeof (char *));
844	static const char separators[] = " \t";
845
846	if (argv == NULL)
847		return (0);
848
849	if ((argv[argc++] = strtok(command, separators)) == 0) {
850		free(argv);
851		return (0);
852	}
853	while ((argv[argc++] = strtok(NULL, separators)))
854		continue;
855	return (argv);
856}
857
858/*
859 * Deallocate a session descriptor.
860 */
861void
862free_session(session_t *sp)
863{
864	free(sp->se_device);
865	if (sp->se_getty) {
866		free(sp->se_getty);
867		free(sp->se_getty_argv);
868	}
869	if (sp->se_window) {
870		free(sp->se_window);
871		free(sp->se_window_argv);
872	}
873	free(sp);
874}
875
876/*
877 * Allocate a new session descriptor.
878 */
879session_t *
880new_session(session_t *sprev, int session_index, struct ttyent *typ)
881{
882	session_t *sp;
883
884	if ((typ->ty_status & TTY_ON) == 0 ||
885	    typ->ty_name == 0 ||
886	    typ->ty_getty == 0)
887		return (0);
888
889	sp = calloc(1, sizeof (session_t));
890	if (sp == NULL)
891		err(1, "calloc");
892
893	sp->se_flags = SE_PRESENT;
894	sp->se_index = session_index;
895
896	if (asprintf(&sp->se_device, "%s%s", _PATH_DEV, typ->ty_name) == -1)
897		err(1, "asprintf");
898
899	if (setupargv(sp, typ) == 0) {
900		free_session(sp);
901		return (0);
902	}
903
904	sp->se_next = NULL;
905	if (sprev == NULL) {
906		sessions = sp;
907		sp->se_prev = NULL;
908	} else {
909		sprev->se_next = sp;
910		sp->se_prev = sprev;
911	}
912
913	return (sp);
914}
915
916/*
917 * Calculate getty and if useful window argv vectors.
918 */
919int
920setupargv(session_t *sp, struct ttyent *typ)
921{
922	if (sp->se_getty) {
923		free(sp->se_getty);
924		free(sp->se_getty_argv);
925	}
926	if (asprintf(&sp->se_getty, "%s %s", typ->ty_getty, typ->ty_name) == -1)
927		err(1, "asprintf");
928	sp->se_getty_argv = construct_argv(sp->se_getty);
929	if (sp->se_getty_argv == 0) {
930		warning("can't parse getty for port %s", sp->se_device);
931		free(sp->se_getty);
932		sp->se_getty = NULL;
933		return (0);
934	}
935	if (typ->ty_window) {
936		free(sp->se_window);
937		sp->se_window = strdup(typ->ty_window);
938		if (sp->se_window == NULL) {
939			warning("can't allocate window");
940			return (0);
941		}
942		sp->se_window_argv = construct_argv(sp->se_window);
943		if (sp->se_window_argv == NULL) {
944			warning("can't parse window for port %s",
945			    sp->se_device);
946			free(sp->se_window);
947			sp->se_window = NULL;
948			return (0);
949		}
950	}
951	return (1);
952}
953
954/*
955 * Walk the list of ttys and create sessions for each active line.
956 */
957state_t
958f_read_ttys(void)
959{
960	int session_index = 0;
961	session_t *sp, *snext;
962	struct ttyent *typ;
963
964	/*
965	 * Destroy any previous session state.
966	 * There shouldn't be any, but just in case...
967	 */
968	for (sp = sessions; sp; sp = snext) {
969		if (sp->se_process)
970			clear_session_logs(sp);
971		snext = sp->se_next;
972		free_session(sp);
973	}
974	sessions = NULL;
975	if (start_session_db())
976		return single_user;
977
978	/*
979	 * Allocate a session entry for each active port.
980	 * Note that sp starts at 0.
981	 */
982	while ((typ = getttyent()))
983		if ((snext = new_session(sp, ++session_index, typ)))
984			sp = snext;
985
986	endttyent();
987
988	return multi_user;
989}
990
991/*
992 * Start a window system running.
993 */
994void
995start_window_system(session_t *sp)
996{
997	pid_t pid;
998	sigset_t mask;
999
1000	if ((pid = fork()) == -1) {
1001		emergency("can't fork for window system on port %s: %m",
1002		    sp->se_device);
1003		/* hope that getty fails and we can try again */
1004		return;
1005	}
1006
1007	if (pid)
1008		return;
1009
1010	sigemptyset(&mask);
1011	sigprocmask(SIG_SETMASK, &mask, NULL);
1012
1013	if (setsid() < 0)
1014		emergency("setsid failed (window) %m");
1015
1016	setprocresources(RESOURCE_WINDOW);
1017
1018	execv(sp->se_window_argv[0], sp->se_window_argv);
1019	stall("can't exec window system '%s' for port %s: %m",
1020	    sp->se_window_argv[0], sp->se_device);
1021	_exit(1);
1022}
1023
1024/*
1025 * Start a login session running.
1026 * For first open, man-handle tty directly to determine if it
1027 * really exists. It is not efficient to spawn gettys on devices
1028 * that do not exist.
1029 */
1030pid_t
1031start_getty(session_t *sp)
1032{
1033	pid_t pid;
1034	sigset_t mask;
1035	time_t current_time = time(NULL);
1036	int p[2], new = 1;
1037
1038	if (sp->se_flags & SE_DEVEXISTS)
1039		new = 0;
1040
1041	if (new) {
1042		if (pipe(p) == -1)
1043			return (-1);
1044	}
1045
1046	/*
1047	 * fork(), not vfork() -- we can't afford to block.
1048	 */
1049	if ((pid = fork()) == -1) {
1050		emergency("can't fork for getty on port %s: %m", sp->se_device);
1051		return (-1);
1052	}
1053
1054	if (pid) {
1055		if (new) {
1056			char c;
1057
1058			close(p[1]);
1059			if (read(p[0], &c, 1) != 1) {
1060				close(p[0]);
1061				return (-1);
1062			}
1063			close(p[0]);
1064			if (c == '1')
1065				sp->se_flags |= SE_DEVEXISTS;
1066			else
1067				sp->se_flags |= SE_SHUTDOWN;
1068		}
1069		return (pid);
1070	}
1071	if (new) {
1072		int fd;
1073
1074		close(p[0]);
1075		fd = open(sp->se_device, O_RDONLY | O_NONBLOCK, 0666);
1076		if (fd == -1 && (errno == ENXIO || errno == ENOENT ||
1077		    errno == EISDIR)) {
1078			(void)write(p[1], "0", 1);
1079			close(p[1]);
1080			_exit(1);
1081		}
1082		(void)write(p[1], "1", 1);
1083		close(p[1]);
1084		close(fd);
1085		sleep(1);
1086	}
1087
1088	if (current_time > sp->se_started &&
1089	    current_time - sp->se_started < GETTY_SPACING) {
1090		warning("getty repeating too quickly on port %s, sleeping",
1091		    sp->se_device);
1092		sleep(GETTY_SLEEP);
1093	}
1094
1095	if (sp->se_window) {
1096		start_window_system(sp);
1097		sleep(WINDOW_WAIT);
1098	}
1099
1100	sigemptyset(&mask);
1101	sigprocmask(SIG_SETMASK, &mask, NULL);
1102
1103	setprocresources(RESOURCE_GETTY);
1104
1105	execv(sp->se_getty_argv[0], sp->se_getty_argv);
1106	stall("can't exec getty '%s' for port %s: %m",
1107	    sp->se_getty_argv[0], sp->se_device);
1108	_exit(1);
1109}
1110
1111/*
1112 * Collect exit status for a child.
1113 * If an exiting login, start a new login running.
1114 */
1115void
1116collect_child(pid_t pid)
1117{
1118	session_t *sp, *sprev, *snext;
1119
1120	if (sessions == NULL)
1121		return;
1122
1123	if ((sp = find_session(pid)) == NULL)
1124		return;
1125
1126	clear_session_logs(sp);
1127	login_fbtab(sp->se_device + sizeof(_PATH_DEV) - 1, 0, 0);
1128	del_session(sp);
1129	sp->se_process = 0;
1130
1131	if (sp->se_flags & SE_SHUTDOWN) {
1132		if ((sprev = sp->se_prev))
1133			sprev->se_next = sp->se_next;
1134		else
1135			sessions = sp->se_next;
1136		if ((snext = sp->se_next))
1137			snext->se_prev = sp->se_prev;
1138		free_session(sp);
1139		return;
1140	}
1141
1142	if ((pid = start_getty(sp)) == -1) {
1143		/* serious trouble */
1144		requested_transition = clean_ttys;
1145		return;
1146	}
1147
1148	sp->se_process = pid;
1149	sp->se_started = time(NULL);
1150	add_session(sp);
1151}
1152
1153/*
1154 * Catch a signal and request a state transition.
1155 */
1156void
1157transition_handler(int sig)
1158{
1159
1160	switch (sig) {
1161	case SIGHUP:
1162		requested_transition = clean_ttys;
1163		break;
1164	case SIGINT:
1165		requested_transition = do_reboot;
1166		break;
1167	case SIGTERM:
1168		requested_transition = death;
1169		break;
1170	case SIGUSR1:
1171		requested_transition = nice_death;
1172		break;
1173	case SIGUSR2:
1174		requested_transition = hard_death;
1175		break;
1176	case SIGTSTP:
1177		requested_transition = catatonia;
1178		break;
1179	default:
1180		requested_transition = 0;
1181		break;
1182	}
1183}
1184
1185/*
1186 * Take the system multiuser.
1187 */
1188state_t
1189f_multi_user(void)
1190{
1191	pid_t pid;
1192	session_t *sp;
1193
1194	/*
1195	 * If the administrator has not set the security level to -1
1196	 * to indicate that the kernel should not run multiuser in secure
1197	 * mode, and the run script has not set a higher level of security
1198	 * than level 1, then put the kernel into secure mode.
1199	 */
1200	if (requested_transition != catatonia) {
1201		if (getsecuritylevel() == 0)
1202			setsecuritylevel(1);
1203	}
1204
1205	requested_transition = 0;
1206
1207	for (sp = sessions; sp; sp = sp->se_next) {
1208		if (sp->se_process)
1209			continue;
1210		if ((pid = start_getty(sp)) == -1) {
1211			/* serious trouble */
1212			requested_transition = clean_ttys;
1213			break;
1214		}
1215		sp->se_process = pid;
1216		sp->se_started = time(NULL);
1217		add_session(sp);
1218	}
1219
1220	while (!requested_transition)
1221		if ((pid = waitpid(-1, NULL, 0)) != -1)
1222			collect_child(pid);
1223
1224	return requested_transition;
1225}
1226
1227/*
1228 * This is an n-squared algorithm.  We hope it isn't run often...
1229 */
1230state_t
1231f_clean_ttys(void)
1232{
1233	session_t *sp, *sprev;
1234	struct ttyent *typ;
1235	int session_index = 0;
1236	int devlen;
1237
1238	for (sp = sessions; sp; sp = sp->se_next)
1239		sp->se_flags &= ~SE_PRESENT;
1240
1241	devlen = sizeof(_PATH_DEV) - 1;
1242	while ((typ = getttyent())) {
1243		++session_index;
1244
1245		for (sprev = NULL, sp = sessions; sp; sprev = sp, sp = sp->se_next)
1246			if (strcmp(typ->ty_name, sp->se_device + devlen) == 0)
1247				break;
1248
1249		if (sp) {
1250			sp->se_flags |= SE_PRESENT;
1251			if (sp->se_index != session_index) {
1252				warning("port %s changed utmp index from %d to %d",
1253				    sp->se_device, sp->se_index,
1254				    session_index);
1255				sp->se_index = session_index;
1256			}
1257			if ((typ->ty_status & TTY_ON) == 0 ||
1258			    typ->ty_getty == 0) {
1259				sp->se_flags |= SE_SHUTDOWN;
1260				kill(sp->se_process, SIGHUP);
1261				continue;
1262			}
1263			sp->se_flags &= ~SE_SHUTDOWN;
1264			if (setupargv(sp, typ) == 0) {
1265				warning("can't parse getty for port %s",
1266				    sp->se_device);
1267				sp->se_flags |= SE_SHUTDOWN;
1268				kill(sp->se_process, SIGHUP);
1269			}
1270			continue;
1271		}
1272
1273		new_session(sprev, session_index, typ);
1274	}
1275
1276	endttyent();
1277
1278	for (sp = sessions; sp; sp = sp->se_next)
1279		if ((sp->se_flags & SE_PRESENT) == 0) {
1280			sp->se_flags |= SE_SHUTDOWN;
1281			kill(sp->se_process, SIGHUP);
1282		}
1283
1284	return multi_user;
1285}
1286
1287/*
1288 * Block further logins.
1289 */
1290state_t
1291f_catatonia(void)
1292{
1293	session_t *sp;
1294
1295	for (sp = sessions; sp; sp = sp->se_next)
1296		sp->se_flags |= SE_SHUTDOWN;
1297
1298	return multi_user;
1299}
1300
1301/*
1302 * Note SIGALRM.
1303 */
1304void
1305alrm_handler(int sig)
1306{
1307	clang = 1;
1308}
1309
1310int death_howto = RB_HALT;
1311
1312/*
1313 * Reboot the system.
1314 */
1315state_t
1316f_do_reboot(void)
1317{
1318	death_howto = RB_AUTOBOOT;
1319	return nice_death;
1320}
1321
1322/*
1323 * Bring the system down nicely, then we must powerdown because something
1324 * is very wrong.
1325 */
1326state_t
1327f_hard_death(void)
1328{
1329	death_howto |= RB_POWERDOWN;
1330	return nice_death;
1331}
1332
1333/*
1334 * Bring the system down to single user nicely, after run the shutdown script.
1335 */
1336state_t
1337f_nice_death(void)
1338{
1339	session_t *sp;
1340	int i;
1341	pid_t pid;
1342	static const int death_sigs[3] = { SIGHUP, SIGTERM, SIGKILL };
1343	int status;
1344
1345#ifdef CPU_LIDSUSPEND
1346	int lidsuspend_mib[] = {CTL_MACHDEP, CPU_LIDSUSPEND};
1347	int dontsuspend = 0;
1348
1349	if ((death_howto & RB_POWERDOWN) &&
1350	    (sysctl(lidsuspend_mib, 2, NULL, NULL, &dontsuspend,
1351		    sizeof(dontsuspend)) == -1) && (errno != EOPNOTSUPP))
1352			warning("cannot disable lid suspend");
1353#endif
1354
1355	for (sp = sessions; sp; sp = sp->se_next) {
1356		sp->se_flags &= ~SE_PRESENT;
1357		sp->se_flags |= SE_SHUTDOWN;
1358		kill(sp->se_process, SIGHUP);
1359	}
1360
1361	/* terminate the accounting process */
1362	acct(NULL);
1363
1364	/* NB: should send a message to the session logger to avoid blocking. */
1365	logwtmp("~", "shutdown", "");
1366
1367	if (access(_PATH_RUNCOM, R_OK) != -1) {
1368		struct sigaction sa;
1369
1370		switch ((pid = fork())) {
1371		case -1:
1372			break;
1373		case 0:
1374
1375			memset(&sa, 0, sizeof sa);
1376			sigemptyset(&sa.sa_mask);
1377			sa.sa_flags = 0;
1378			sa.sa_handler = SIG_IGN;
1379			(void) sigaction(SIGTSTP, &sa, NULL);
1380			(void) sigaction(SIGHUP, &sa, NULL);
1381
1382			setctty(_PATH_CONSOLE);
1383
1384			sigprocmask(SIG_SETMASK, &sa.sa_mask, NULL);
1385
1386			execl(_PATH_BSHELL, "sh", _PATH_RUNCOM, "shutdown",
1387			    (char *)NULL);
1388			stall("can't exec %s for %s %s: %m", _PATH_BSHELL,
1389			    _PATH_RUNCOM, "shutdown");
1390			_exit(1);
1391		default:
1392			waitpid(pid, &status, 0);
1393			if (WIFEXITED(status) && WEXITSTATUS(status) == 2)
1394				death_howto |= RB_POWERDOWN;
1395		}
1396	}
1397
1398	for (i = 0; i < 3; ++i) {
1399		if (kill(-1, death_sigs[i]) == -1 && errno == ESRCH)
1400			goto die;
1401
1402		clang = 0;
1403		alarm(DEATH_WATCH);
1404		do {
1405			if ((pid = waitpid(-1, NULL, 0)) != -1)
1406				collect_child(pid);
1407		} while (clang == 0 && errno != ECHILD);
1408
1409		if (errno == ECHILD)
1410			goto die;
1411	}
1412
1413	warning("some processes would not die; ps axl advised");
1414
1415die:
1416	reboot(death_howto);
1417
1418	/* ... and if that fails.. oh well */
1419	return single_user;
1420}
1421
1422/*
1423 * Bring the system down to single user.
1424 */
1425state_t
1426f_death(void)
1427{
1428	session_t *sp;
1429	int i;
1430	pid_t pid;
1431	static const int death_sigs[3] = { SIGHUP, SIGTERM, SIGKILL };
1432
1433	/* terminate the accounting process */
1434	acct(NULL);
1435
1436	for (sp = sessions; sp; sp = sp->se_next)
1437		sp->se_flags |= SE_SHUTDOWN;
1438
1439	/* NB: should send a message to the session logger to avoid blocking. */
1440	logwtmp("~", "shutdown", "");
1441
1442	for (i = 0; i < 3; ++i) {
1443		if (kill(-1, death_sigs[i]) == -1 && errno == ESRCH)
1444			return single_user;
1445
1446		clang = 0;
1447		alarm(DEATH_WATCH);
1448		do {
1449			if ((pid = waitpid(-1, NULL, 0)) != -1)
1450				collect_child(pid);
1451		} while (clang == 0 && errno != ECHILD);
1452
1453		if (errno == ECHILD)
1454			return single_user;
1455	}
1456
1457	warning("some processes would not die; ps axl advised");
1458
1459	return single_user;
1460}
1461
1462#ifdef LOGIN_CAP
1463void
1464setprocresources(char *class)
1465{
1466	login_cap_t *lc;
1467
1468	if ((lc = login_getclass(class)) != NULL) {
1469		setusercontext(lc, NULL, 0,
1470		    LOGIN_SETPRIORITY|LOGIN_SETRESOURCES|LOGIN_SETUMASK);
1471		login_close(lc);
1472	}
1473}
1474#endif
1475