init.c revision 1.48 
1/*	$OpenBSD: init.c,v 1.48 2013/02/11 15:52:42 millert Exp $	*/
2/*	$NetBSD: init.c,v 1.22 1996/05/15 23:29:33 jtc Exp $	*/
3
4/*-
5 * Copyright (c) 1991, 1993
6 *	The Regents of the University of California.  All rights reserved.
7 *
8 * This code is derived from software contributed to Berkeley by
9 * Donn Seeley at Berkeley Software Design, Inc.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 *    notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 *    notice, this list of conditions and the following disclaimer in the
18 *    documentation and/or other materials provided with the distribution.
19 * 3. 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/param.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
96/*
97 * We really need a recursive typedef...
98 * The following at least guarantees that the return type of (*state_t)()
99 * is sufficiently wide to hold a function pointer.
100 */
101typedef long (*state_func_t)(void);
102typedef state_func_t (*state_t)(void);
103
104state_func_t single_user(void);
105state_func_t runcom(void);
106state_func_t read_ttys(void);
107state_func_t multi_user(void);
108state_func_t clean_ttys(void);
109state_func_t catatonia(void);
110state_func_t death(void);
111state_func_t do_reboot(void);
112state_func_t hard_death(void);
113state_func_t nice_death(void);
114
115enum { AUTOBOOT, FASTBOOT } runcom_mode = AUTOBOOT;
116
117void transition(state_t);
118state_t requested_transition = DEFAULT_STATE;
119
120void setctty(char *);
121
122typedef struct init_session {
123	int	se_index;		/* index of entry in ttys file */
124	pid_t	se_process;		/* controlling process */
125	time_t	se_started;		/* used to avoid thrashing */
126	int	se_flags;		/* status of session */
127#define	SE_SHUTDOWN	0x1		/* session won't be restarted */
128#define	SE_PRESENT	0x2		/* session is in /etc/ttys */
129#define	SE_DEVEXISTS	0x4		/* open does not result in ENODEV */
130	char	*se_device;		/* filename of port */
131	char	*se_getty;		/* what to run on that port */
132	char	**se_getty_argv;	/* pre-parsed argument array */
133	char	*se_window;		/* window system (started only once) */
134	char	**se_window_argv;	/* pre-parsed argument array */
135	struct	init_session *se_prev;
136	struct	init_session *se_next;
137} session_t;
138
139void free_session(session_t *);
140session_t *new_session(session_t *, int, struct ttyent *);
141session_t *sessions;
142
143char **construct_argv(char *);
144void start_window_system(session_t *);
145void collect_child(pid_t);
146pid_t start_getty(session_t *);
147void transition_handler(int);
148void alrm_handler(int);
149void setsecuritylevel(int);
150int getsecuritylevel(void);
151int setupargv(session_t *, struct ttyent *);
152int clang;
153
154#ifdef LOGIN_CAP
155void setprocresources(char *);
156#else
157#define setprocresources(p)
158#endif
159
160void clear_session_logs(session_t *);
161
162int start_session_db(void);
163void add_session(session_t *);
164void del_session(session_t *);
165session_t *find_session(pid_t);
166DB *session_db;
167
168/*
169 * The mother of all processes.
170 */
171int
172main(int argc, 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, SIGINT, SIGTERM, SIGTSTP,
237            SIGUSR1, SIGUSR2, 0);
238	handle(alrm_handler, SIGALRM, 0);
239	sigfillset(&mask);
240	delset(&mask, SIGABRT, SIGFPE, SIGILL, SIGSEGV, SIGBUS, SIGSYS,
241	    SIGXCPU, SIGXFSZ, SIGHUP, SIGINT, SIGTERM, SIGUSR1, SIGUSR2,
242	    SIGTSTP, SIGALRM, 0);
243	sigprocmask(SIG_SETMASK, &mask, NULL);
244	memset(&sa, 0, sizeof sa);
245	sigemptyset(&sa.sa_mask);
246	sa.sa_flags = 0;
247	sa.sa_handler = SIG_IGN;
248	(void) sigaction(SIGTTIN, &sa, NULL);
249	(void) sigaction(SIGTTOU, &sa, NULL);
250
251	/*
252	 * Paranoia.
253	 */
254	close(STDIN_FILENO);
255	close(STDOUT_FILENO);
256	close(STDERR_FILENO);
257
258	/*
259	 * Start the state machine.
260	 */
261	transition(requested_transition);
262
263	/*
264	 * Should never reach here.
265	 */
266	exit(1);
267}
268
269/*
270 * Associate a function with a signal handler.
271 */
272void
273handle(sig_t handler, ...)
274{
275	int sig;
276	struct sigaction sa;
277	sigset_t mask_everything;
278	va_list ap;
279
280	va_start(ap, handler);
281
282	memset(&sa, 0, sizeof sa);
283	sa.sa_handler = handler;
284	sigfillset(&mask_everything);
285
286	while ((sig = va_arg(ap, int))) {
287		sa.sa_mask = mask_everything;
288		/* XXX SA_RESTART? */
289		sa.sa_flags = sig == SIGCHLD ? SA_NOCLDSTOP : 0;
290		sigaction(sig, &sa, NULL);
291	}
292	va_end(ap);
293}
294
295/*
296 * Delete a set of signals from a mask.
297 */
298void
299delset(sigset_t *maskp, ...)
300{
301	int sig;
302	va_list ap;
303
304	va_start(ap, maskp);
305	while ((sig = va_arg(ap, int)))
306		sigdelset(maskp, sig);
307	va_end(ap);
308}
309
310/*
311 * Log a message and sleep for a while (to give someone an opportunity
312 * to read it and to save log or hardcopy output if the problem is chronic).
313 * NB: should send a message to the session logger to avoid blocking.
314 */
315void
316stall(char *message, ...)
317{
318	va_list ap;
319
320	va_start(ap, message);
321	vsyslog(LOG_ALERT, message, ap);
322	va_end(ap);
323	closelog();
324	sleep(STALL_TIMEOUT);
325}
326
327/*
328 * Like stall(), but doesn't sleep.
329 * If cpp had variadic macros, the two functions could be #defines for another.
330 * NB: should send a message to the session logger to avoid blocking.
331 */
332void
333warning(char *message, ...)
334{
335	va_list ap;
336
337	va_start(ap, message);
338	vsyslog(LOG_ALERT, message, ap);
339	va_end(ap);
340	closelog();
341}
342
343/*
344 * Log an emergency message.
345 * NB: should send a message to the session logger to avoid blocking.
346 */
347void
348emergency(char *message, ...)
349{
350	struct syslog_data sdata = SYSLOG_DATA_INIT;
351	va_list ap;
352
353	va_start(ap, message);
354	vsyslog_r(LOG_EMERG, &sdata, message, ap);
355	va_end(ap);
356}
357
358/*
359 * Catch a SIGSYS signal.
360 *
361 * These may arise if a system does not support sysctl.
362 * We tolerate up to 25 of these, then throw in the towel.
363 */
364void
365badsys(int sig)
366{
367	static int badcount = 0;
368
369	if (badcount++ < 25)
370		return;
371	disaster(sig);
372}
373
374/*
375 * Catch an unexpected signal.
376 */
377void
378disaster(int sig)
379{
380	emergency("fatal signal: %s", strsignal(sig));
381
382	sleep(STALL_TIMEOUT);
383	_exit(sig);		/* reboot */
384}
385
386/*
387 * Get the security level of the kernel.
388 */
389int
390getsecuritylevel(void)
391{
392#ifdef KERN_SECURELVL
393	int name[2], curlevel;
394	size_t len;
395
396	name[0] = CTL_KERN;
397	name[1] = KERN_SECURELVL;
398	len = sizeof curlevel;
399	if (sysctl(name, 2, &curlevel, &len, NULL, 0) == -1) {
400		emergency("cannot get kernel security level: %s",
401		    strerror(errno));
402		return (-1);
403	}
404	return (curlevel);
405#else
406	return (-1);
407#endif
408}
409
410/*
411 * Set the security level of the kernel.
412 */
413void
414setsecuritylevel(int newlevel)
415{
416#ifdef KERN_SECURELVL
417	int name[2], curlevel;
418
419	curlevel = getsecuritylevel();
420	if (newlevel == curlevel)
421		return;
422	name[0] = CTL_KERN;
423	name[1] = KERN_SECURELVL;
424	if (sysctl(name, 2, NULL, NULL, &newlevel, sizeof newlevel) == -1) {
425		emergency(
426		    "cannot change kernel security level from %d to %d: %s",
427		    curlevel, newlevel, strerror(errno));
428		return;
429	}
430#ifdef SECURE
431	warning("kernel security level changed from %d to %d",
432	    curlevel, newlevel);
433#endif
434#endif
435}
436
437/*
438 * Change states in the finite state machine.
439 * The initial state is passed as an argument.
440 */
441void
442transition(state_t s)
443{
444	for (;;)
445		s = (state_t) (*s)();
446}
447
448/*
449 * Close out the accounting files for a login session.
450 * NB: should send a message to the session logger to avoid blocking.
451 */
452void
453clear_session_logs(session_t *sp)
454{
455	char *line = sp->se_device + sizeof(_PATH_DEV) - 1;
456
457	if (logout(line))
458		logwtmp(line, "", "");
459}
460
461/*
462 * Start a session and allocate a controlling terminal.
463 * Only called by children of init after forking.
464 */
465void
466setctty(char *name)
467{
468	int fd;
469
470	(void) revoke(name);
471	sleep(2);			/* leave DTR low */
472	if ((fd = open(name, O_RDWR)) == -1) {
473		stall("can't open %s: %m", name);
474		_exit(1);
475	}
476	if (login_tty(fd) == -1) {
477		stall("can't get %s for controlling terminal: %m", name);
478		_exit(1);
479	}
480}
481
482/*
483 * Bring the system up single user.
484 */
485state_func_t
486single_user(void)
487{
488	pid_t pid, wpid;
489	int status;
490	sigset_t mask;
491	char shell[MAXPATHLEN];		/* Allocate space here */
492	char name[MAXPATHLEN];		/* Name (argv[0]) of shell */
493	char *argv[2];
494#ifdef SECURE
495	struct ttyent *typ;
496	struct passwd *pp;
497	static const char banner[] =
498		"Enter root password, or ^D to go multi-user\n";
499	char *clear, *password;
500#endif
501
502	/* Init shell and name */
503	strlcpy(shell, _PATH_BSHELL, sizeof shell);
504	strlcpy(name, "-sh", sizeof name);
505
506	/*
507	 * If the kernel is in secure mode, downgrade it to insecure mode.
508	 */
509	if (getsecuritylevel() > 0)
510		setsecuritylevel(0);
511
512	if ((pid = fork()) == 0) {
513		/*
514		 * Start the single user session.
515		 */
516		setctty(_PATH_CONSOLE);
517
518#ifdef SECURE
519		/*
520		 * Check the root password.
521		 * We don't care if the console is 'on' by default;
522		 * it's the only tty that can be 'off' and 'secure'.
523		 */
524		typ = getttynam("console");
525		pp = getpwnam("root");
526		if (typ && (typ->ty_status & TTY_SECURE) == 0 && pp &&
527		    *pp->pw_passwd) {
528			write(STDERR_FILENO, banner, sizeof banner - 1);
529			for (;;) {
530				clear = getpass("Password:");
531				if (clear == 0 || *clear == '\0')
532					_exit(0);
533				password = crypt(clear, pp->pw_passwd);
534				memset(clear, 0, _PASSWORD_LEN);
535				if (strcmp(password, pp->pw_passwd) == 0)
536					break;
537				warning("single-user login failed\n");
538			}
539		}
540		endttyent();
541		endpwent();
542#endif /* SECURE */
543
544#ifdef DEBUGSHELL
545		{
546			char altshell[128], *cp = altshell;
547			int num;
548
549#define	SHREQUEST \
550	"Enter pathname of shell or RETURN for sh: "
551
552			(void)write(STDERR_FILENO,
553			    SHREQUEST, sizeof(SHREQUEST) - 1);
554			while ((num = read(STDIN_FILENO, cp, 1)) != -1 &&
555			    num != 0 && *cp != '\n' && cp < &altshell[127])
556				cp++;
557			*cp = '\0';
558
559			/* Copy in alternate shell */
560			if (altshell[0] != '\0'){
561				char *p;
562
563				/* Binary to exec */
564				strlcpy(shell, altshell, sizeof shell);
565
566				/* argv[0] */
567				p = strrchr(altshell, '/');
568				if(p == NULL) p = altshell;
569				else p++;
570
571				name[0] = '-';
572				strlcpy(&name[1], p, sizeof name -1);
573			}
574		}
575#endif /* DEBUGSHELL */
576
577		/*
578		 * Unblock signals.
579		 * We catch all the interesting ones,
580		 * and those are reset to SIG_DFL on exec.
581		 */
582		sigemptyset(&mask);
583		sigprocmask(SIG_SETMASK, &mask, NULL);
584
585		/*
586		 * Fire off a shell.
587		 * If the default one doesn't work, try the Bourne shell.
588		 */
589		argv[0] = name;
590		argv[1] = NULL;
591		setenv("PATH", _PATH_STDPATH, 1);
592		execv(shell, argv);
593		emergency("can't exec %s for single user: %m", shell);
594
595		argv[0] = "-sh";
596		argv[1] = NULL;
597		execv(_PATH_BSHELL, argv);
598		emergency("can't exec %s for single user: %m", _PATH_BSHELL);
599		sleep(STALL_TIMEOUT);
600		_exit(1);
601	}
602
603	if (pid == -1) {
604		/*
605		 * We are seriously hosed.  Do our best.
606		 */
607		emergency("can't fork single-user shell, trying again");
608		while (waitpid(-1, NULL, WNOHANG) > 0)
609			continue;
610		return (state_func_t) single_user;
611	}
612
613	requested_transition = 0;
614	do {
615		if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1)
616			collect_child(wpid);
617		if (wpid == -1) {
618			if (errno == EINTR)
619				continue;
620			warning("wait for single-user shell failed: %m; restarting");
621			return (state_func_t) single_user;
622		}
623		if (wpid == pid && WIFSTOPPED(status)) {
624			warning("init: shell stopped, restarting\n");
625			kill(pid, SIGCONT);
626			wpid = -1;
627		}
628	} while (wpid != pid && !requested_transition);
629
630	if (requested_transition)
631		return (state_func_t) requested_transition;
632
633	if (!WIFEXITED(status)) {
634		if (WTERMSIG(status) == SIGKILL) {
635			/*
636			 *  reboot(8) killed shell?
637			 */
638			warning("single user shell terminated.");
639			sleep(STALL_TIMEOUT);
640			_exit(0);
641		} else {
642			warning("single user shell terminated, restarting");
643			return (state_func_t) single_user;
644		}
645	}
646
647	runcom_mode = FASTBOOT;
648	return (state_func_t) runcom;
649}
650
651/*
652 * Run the system startup script.
653 */
654state_func_t
655runcom(void)
656{
657	pid_t pid, wpid;
658	int status;
659	char *argv[4];
660	struct sigaction sa;
661
662	if ((pid = fork()) == 0) {
663		memset(&sa, 0, sizeof sa);
664		sigemptyset(&sa.sa_mask);
665		sa.sa_flags = 0;
666		sa.sa_handler = SIG_IGN;
667		(void) sigaction(SIGTSTP, &sa, NULL);
668		(void) sigaction(SIGHUP, &sa, NULL);
669
670		setctty(_PATH_CONSOLE);
671
672		argv[0] = "sh";
673		argv[1] = _PATH_RUNCOM;
674		argv[2] = runcom_mode == AUTOBOOT ? "autoboot" : 0;
675		argv[3] = 0;
676
677		sigprocmask(SIG_SETMASK, &sa.sa_mask, NULL);
678
679		setprocresources(RESOURCE_RC);
680
681		execv(_PATH_BSHELL, argv);
682		stall("can't exec %s for %s: %m", _PATH_BSHELL, _PATH_RUNCOM);
683		_exit(1);	/* force single user mode */
684	}
685
686	if (pid == -1) {
687		emergency("can't fork for %s on %s: %m",
688			_PATH_BSHELL, _PATH_RUNCOM);
689		while (waitpid(-1, NULL, WNOHANG) > 0)
690			continue;
691		sleep(STALL_TIMEOUT);
692		return (state_func_t) single_user;
693	}
694
695	/*
696	 * Copied from single_user().  This is a bit paranoid.
697	 */
698	do {
699		if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1)
700			collect_child(wpid);
701		if (wpid == -1) {
702			if (errno == EINTR)
703				continue;
704			warning("wait for %s on %s failed: %m; going to single user mode",
705			    _PATH_BSHELL, _PATH_RUNCOM);
706			return (state_func_t) single_user;
707		}
708		if (wpid == pid && WIFSTOPPED(status)) {
709			warning("init: %s on %s stopped, restarting\n",
710			    _PATH_BSHELL, _PATH_RUNCOM);
711			kill(pid, SIGCONT);
712			wpid = -1;
713		}
714	} while (wpid != pid);
715
716	if (WIFSIGNALED(status) && WTERMSIG(status) == SIGTERM &&
717	    requested_transition == catatonia) {
718		/* /etc/rc executed /sbin/reboot; wait for the end quietly */
719		sigset_t s;
720
721		sigfillset(&s);
722		for (;;)
723			sigsuspend(&s);
724	}
725
726	if (!WIFEXITED(status)) {
727		warning("%s on %s terminated abnormally, going to single user mode",
728		    _PATH_BSHELL, _PATH_RUNCOM);
729		return (state_func_t) single_user;
730	}
731
732	if (WEXITSTATUS(status))
733		return (state_func_t) single_user;
734
735	runcom_mode = AUTOBOOT;		/* the default */
736	/* NB: should send a message to the session logger to avoid blocking. */
737	logwtmp("~", "reboot", "");
738	return (state_func_t) read_ttys;
739}
740
741/*
742 * Open the session database.
743 *
744 * NB: We could pass in the size here; is it necessary?
745 */
746int
747start_session_db(void)
748{
749	if (session_db && (*session_db->close)(session_db))
750		emergency("session database close: %s", strerror(errno));
751	if ((session_db = dbopen(NULL, O_RDWR, 0, DB_HASH, NULL)) == 0) {
752		emergency("session database open: %s", strerror(errno));
753		return (1);
754	}
755	return (0);
756}
757
758/*
759 * Add a new login session.
760 */
761void
762add_session(session_t *sp)
763{
764	DBT key;
765	DBT data;
766
767	key.data = &sp->se_process;
768	key.size = sizeof sp->se_process;
769	data.data = &sp;
770	data.size = sizeof sp;
771
772	if ((*session_db->put)(session_db, &key, &data, 0))
773		emergency("insert %d: %s", sp->se_process, strerror(errno));
774}
775
776/*
777 * Delete an old login session.
778 */
779void
780del_session(session_t *sp)
781{
782	DBT key;
783
784	key.data = &sp->se_process;
785	key.size = sizeof sp->se_process;
786
787	if ((*session_db->del)(session_db, &key, 0))
788		emergency("delete %d: %s", sp->se_process, strerror(errno));
789}
790
791/*
792 * Look up a login session by pid.
793 */
794session_t *
795find_session(pid_t pid)
796{
797	DBT key;
798	DBT data;
799	session_t *ret;
800
801	key.data = &pid;
802	key.size = sizeof pid;
803	if ((*session_db->get)(session_db, &key, &data, 0) != 0)
804		return (0);
805	memcpy(&ret, data.data, sizeof(ret));
806	return (ret);
807}
808
809/*
810 * Construct an argument vector from a command line.
811 */
812char **
813construct_argv(char *command)
814{
815	int argc = 0;
816	char **argv = (char **) calloc((strlen(command) + 1) / 2 + 1,
817	    sizeof (char *));
818	static const char separators[] = " \t";
819
820	if (argv == NULL)
821		return (0);
822
823	if ((argv[argc++] = strtok(command, separators)) == 0) {
824		free(argv);
825		return (0);
826	}
827	while ((argv[argc++] = strtok(NULL, separators)))
828		continue;
829	return (argv);
830}
831
832/*
833 * Deallocate a session descriptor.
834 */
835void
836free_session(session_t *sp)
837{
838	free(sp->se_device);
839	if (sp->se_getty) {
840		free(sp->se_getty);
841		free(sp->se_getty_argv);
842	}
843	if (sp->se_window) {
844		free(sp->se_window);
845		free(sp->se_window_argv);
846	}
847	free(sp);
848}
849
850/*
851 * Allocate a new session descriptor.
852 */
853session_t *
854new_session(session_t *sprev, int session_index, struct ttyent *typ)
855{
856	session_t *sp;
857
858	if ((typ->ty_status & TTY_ON) == 0 ||
859	    typ->ty_name == 0 ||
860	    typ->ty_getty == 0)
861		return (0);
862
863	sp = (session_t *) malloc(sizeof (session_t));
864	memset(sp, 0, sizeof *sp);
865
866	sp->se_flags = SE_PRESENT;
867	sp->se_index = session_index;
868
869	if (asprintf(&sp->se_device, "%s%s", _PATH_DEV, typ->ty_name) == -1)
870		err(1, "asprintf");
871
872	if (setupargv(sp, typ) == 0) {
873		free_session(sp);
874		return (0);
875	}
876
877	sp->se_next = 0;
878	if (sprev == 0) {
879		sessions = sp;
880		sp->se_prev = 0;
881	} else {
882		sprev->se_next = sp;
883		sp->se_prev = sprev;
884	}
885
886	return (sp);
887}
888
889/*
890 * Calculate getty and if useful window argv vectors.
891 */
892int
893setupargv(session_t *sp, struct ttyent *typ)
894{
895	if (sp->se_getty) {
896		free(sp->se_getty);
897		free(sp->se_getty_argv);
898	}
899	if (asprintf(&sp->se_getty, "%s %s", typ->ty_getty, typ->ty_name) == -1)
900		err(1, "asprintf");
901	sp->se_getty_argv = construct_argv(sp->se_getty);
902	if (sp->se_getty_argv == 0) {
903		warning("can't parse getty for port %s", sp->se_device);
904		free(sp->se_getty);
905		sp->se_getty = 0;
906		return (0);
907	}
908	if (typ->ty_window) {
909		if (sp->se_window)
910			free(sp->se_window);
911		sp->se_window = strdup(typ->ty_window);
912		if (sp->se_window == NULL) {
913			warning("can't allocate window");
914			return (0);
915		}
916		sp->se_window_argv = construct_argv(sp->se_window);
917		if (sp->se_window_argv == NULL) {
918			warning("can't parse window for port %s",
919			    sp->se_device);
920			free(sp->se_window);
921			sp->se_window = NULL;
922			return (0);
923		}
924	}
925	return (1);
926}
927
928/*
929 * Walk the list of ttys and create sessions for each active line.
930 */
931state_func_t
932read_ttys(void)
933{
934	int session_index = 0;
935	session_t *sp, *snext;
936	struct ttyent *typ;
937
938	/*
939	 * Destroy any previous session state.
940	 * There shouldn't be any, but just in case...
941	 */
942	for (sp = sessions; sp; sp = snext) {
943		if (sp->se_process)
944			clear_session_logs(sp);
945		snext = sp->se_next;
946		free_session(sp);
947	}
948	sessions = 0;
949	if (start_session_db())
950		return (state_func_t) single_user;
951
952	/*
953	 * Allocate a session entry for each active port.
954	 * Note that sp starts at 0.
955	 */
956	while ((typ = getttyent()))
957		if ((snext = new_session(sp, ++session_index, typ)))
958			sp = snext;
959
960	endttyent();
961
962	return (state_func_t) multi_user;
963}
964
965/*
966 * Start a window system running.
967 */
968void
969start_window_system(session_t *sp)
970{
971	pid_t pid;
972	sigset_t mask;
973
974	if ((pid = fork()) == -1) {
975		emergency("can't fork for window system on port %s: %m",
976		    sp->se_device);
977		/* hope that getty fails and we can try again */
978		return;
979	}
980
981	if (pid)
982		return;
983
984	sigemptyset(&mask);
985	sigprocmask(SIG_SETMASK, &mask, NULL);
986
987	if (setsid() < 0)
988		emergency("setsid failed (window) %m");
989
990	setprocresources(RESOURCE_WINDOW);
991
992	execv(sp->se_window_argv[0], sp->se_window_argv);
993	stall("can't exec window system '%s' for port %s: %m",
994	    sp->se_window_argv[0], sp->se_device);
995	_exit(1);
996}
997
998/*
999 * Start a login session running.
1000 * For first open, man-handle tty directly to determine if it
1001 * really exists. It is not efficient to spawn gettys on devices
1002 * that do not exist.
1003 */
1004pid_t
1005start_getty(session_t *sp)
1006{
1007	pid_t pid;
1008	sigset_t mask;
1009	time_t current_time = time(NULL);
1010	int p[2], new = 1;
1011
1012	if (sp->se_flags & SE_DEVEXISTS)
1013		new = 0;
1014
1015	if (new) {
1016		if (pipe(p) == -1)
1017			return (-1);
1018	}
1019
1020	/*
1021	 * fork(), not vfork() -- we can't afford to block.
1022	 */
1023	if ((pid = fork()) == -1) {
1024		emergency("can't fork for getty on port %s: %m", sp->se_device);
1025		return (-1);
1026	}
1027
1028	if (pid) {
1029		if (new) {
1030			char c;
1031
1032			close(p[1]);
1033			if (read(p[0], &c, 1) != 1) {
1034				close(p[0]);
1035				return (-1);
1036			}
1037			close(p[0]);
1038			if (c == '1')
1039				sp->se_flags |= SE_DEVEXISTS;
1040			else
1041				sp->se_flags |= SE_SHUTDOWN;
1042		}
1043		return (pid);
1044	}
1045	if (new) {
1046		int fd;
1047
1048		close(p[0]);
1049		fd = open(sp->se_device, O_RDONLY | O_NONBLOCK, 0666);
1050		if (fd == -1 && (errno == ENXIO || errno == ENOENT ||
1051		    errno == EISDIR)) {
1052			(void)write(p[1], "0", 1);
1053			close(p[1]);
1054			_exit(1);
1055		}
1056		(void)write(p[1], "1", 1);
1057		close(p[1]);
1058		close(fd);
1059		sleep(1);
1060	}
1061
1062	if (current_time > sp->se_started &&
1063	    current_time - sp->se_started < GETTY_SPACING) {
1064		warning("getty repeating too quickly on port %s, sleeping",
1065		    sp->se_device);
1066		sleep(GETTY_SLEEP);
1067	}
1068
1069	if (sp->se_window) {
1070		start_window_system(sp);
1071		sleep(WINDOW_WAIT);
1072	}
1073
1074	sigemptyset(&mask);
1075	sigprocmask(SIG_SETMASK, &mask, NULL);
1076
1077	setprocresources(RESOURCE_GETTY);
1078
1079	execv(sp->se_getty_argv[0], sp->se_getty_argv);
1080	stall("can't exec getty '%s' for port %s: %m",
1081	    sp->se_getty_argv[0], sp->se_device);
1082	_exit(1);
1083}
1084
1085/*
1086 * Collect exit status for a child.
1087 * If an exiting login, start a new login running.
1088 */
1089void
1090collect_child(pid_t pid)
1091{
1092	session_t *sp, *sprev, *snext;
1093
1094	if (sessions == NULL)
1095		return;
1096
1097	if ((sp = find_session(pid)) == NULL)
1098		return;
1099
1100	clear_session_logs(sp);
1101	login_fbtab(sp->se_device + sizeof(_PATH_DEV) - 1, 0, 0);
1102	del_session(sp);
1103	sp->se_process = 0;
1104
1105	if (sp->se_flags & SE_SHUTDOWN) {
1106		if ((sprev = sp->se_prev))
1107			sprev->se_next = sp->se_next;
1108		else
1109			sessions = sp->se_next;
1110		if ((snext = sp->se_next))
1111			snext->se_prev = sp->se_prev;
1112		free_session(sp);
1113		return;
1114	}
1115
1116	if ((pid = start_getty(sp)) == -1) {
1117		/* serious trouble */
1118		requested_transition = clean_ttys;
1119		return;
1120	}
1121
1122	sp->se_process = pid;
1123	sp->se_started = time(NULL);
1124	add_session(sp);
1125}
1126
1127/*
1128 * Catch a signal and request a state transition.
1129 */
1130void
1131transition_handler(int sig)
1132{
1133
1134	switch (sig) {
1135	case SIGHUP:
1136		requested_transition = clean_ttys;
1137		break;
1138	case SIGINT:
1139		requested_transition = do_reboot;
1140		break;
1141	case SIGTERM:
1142		requested_transition = death;
1143		break;
1144	case SIGUSR1:
1145		requested_transition = nice_death;
1146		break;
1147	case SIGUSR2:
1148		requested_transition = hard_death;
1149		break;
1150	case SIGTSTP:
1151		requested_transition = catatonia;
1152		break;
1153	default:
1154		requested_transition = 0;
1155		break;
1156	}
1157}
1158
1159/*
1160 * Take the system multiuser.
1161 */
1162state_func_t
1163multi_user(void)
1164{
1165	pid_t pid;
1166	session_t *sp;
1167
1168	requested_transition = 0;
1169
1170	/*
1171	 * If the administrator has not set the security level to -1
1172	 * to indicate that the kernel should not run multiuser in secure
1173	 * mode, and the run script has not set a higher level of security
1174	 * than level 1, then put the kernel into secure mode.
1175	 */
1176	if (getsecuritylevel() == 0)
1177		setsecuritylevel(1);
1178
1179	for (sp = sessions; sp; sp = sp->se_next) {
1180		if (sp->se_process)
1181			continue;
1182		if ((pid = start_getty(sp)) == -1) {
1183			/* serious trouble */
1184			requested_transition = clean_ttys;
1185			break;
1186		}
1187		sp->se_process = pid;
1188		sp->se_started = time(NULL);
1189		add_session(sp);
1190	}
1191
1192	while (!requested_transition)
1193		if ((pid = waitpid(-1, NULL, 0)) != -1)
1194			collect_child(pid);
1195
1196	return (state_func_t) requested_transition;
1197}
1198
1199/*
1200 * This is an n-squared algorithm.  We hope it isn't run often...
1201 */
1202state_func_t
1203clean_ttys(void)
1204{
1205	session_t *sp, *sprev;
1206	struct ttyent *typ;
1207	int session_index = 0;
1208	int devlen;
1209
1210	for (sp = sessions; sp; sp = sp->se_next)
1211		sp->se_flags &= ~SE_PRESENT;
1212
1213	devlen = sizeof(_PATH_DEV) - 1;
1214	while ((typ = getttyent())) {
1215		++session_index;
1216
1217		for (sprev = 0, sp = sessions; sp; sprev = sp, sp = sp->se_next)
1218			if (strcmp(typ->ty_name, sp->se_device + devlen) == 0)
1219				break;
1220
1221		if (sp) {
1222			sp->se_flags |= SE_PRESENT;
1223			if (sp->se_index != session_index) {
1224				warning("port %s changed utmp index from %d to %d",
1225				    sp->se_device, sp->se_index,
1226				    session_index);
1227				sp->se_index = session_index;
1228			}
1229			if ((typ->ty_status & TTY_ON) == 0 ||
1230			    typ->ty_getty == 0) {
1231				sp->se_flags |= SE_SHUTDOWN;
1232				kill(sp->se_process, SIGHUP);
1233				continue;
1234			}
1235			sp->se_flags &= ~SE_SHUTDOWN;
1236			if (setupargv(sp, typ) == 0) {
1237				warning("can't parse getty for port %s",
1238				    sp->se_device);
1239				sp->se_flags |= SE_SHUTDOWN;
1240				kill(sp->se_process, SIGHUP);
1241			}
1242			continue;
1243		}
1244
1245		new_session(sprev, session_index, typ);
1246	}
1247
1248	endttyent();
1249
1250	for (sp = sessions; sp; sp = sp->se_next)
1251		if ((sp->se_flags & SE_PRESENT) == 0) {
1252			sp->se_flags |= SE_SHUTDOWN;
1253			kill(sp->se_process, SIGHUP);
1254		}
1255
1256	return (state_func_t) multi_user;
1257}
1258
1259/*
1260 * Block further logins.
1261 */
1262state_func_t
1263catatonia(void)
1264{
1265	session_t *sp;
1266
1267	for (sp = sessions; sp; sp = sp->se_next)
1268		sp->se_flags |= SE_SHUTDOWN;
1269
1270	return (state_func_t) multi_user;
1271}
1272
1273/*
1274 * Note SIGALRM.
1275 */
1276void
1277alrm_handler(int sig)
1278{
1279	clang = 1;
1280}
1281
1282int death_howto = RB_HALT;
1283
1284/*
1285 * Reboot the system.
1286 */
1287state_func_t
1288do_reboot(void)
1289{
1290	death_howto = RB_AUTOBOOT;
1291	return nice_death();
1292}
1293
1294/*
1295 * Bring the system down nicely, then we must powerdown because something
1296 * is very wrong.
1297 */
1298state_func_t
1299hard_death(void)
1300{
1301	death_howto |= RB_POWERDOWN;
1302	return nice_death();
1303}
1304
1305/*
1306 * Bring the system down to single user nicely, after run the shutdown script.
1307 */
1308state_func_t
1309nice_death(void)
1310{
1311	session_t *sp;
1312	int i;
1313	pid_t pid;
1314	static const int death_sigs[3] = { SIGHUP, SIGTERM, SIGKILL };
1315	int status;
1316
1317#ifdef CPU_LIDSUSPEND
1318	int lidsuspend_mib[] = {CTL_MACHDEP, CPU_LIDSUSPEND};
1319	int dontsuspend = 0;
1320
1321	if ((death_howto & RB_POWERDOWN) &&
1322	    (sysctl(lidsuspend_mib, 2, NULL, NULL, &dontsuspend,
1323		    sizeof(dontsuspend)) == -1) && (errno != EOPNOTSUPP))
1324			warning("cannot disable lid suspend");
1325#endif
1326
1327	for (sp = sessions; sp; sp = sp->se_next) {
1328		sp->se_flags &= ~SE_PRESENT;
1329		sp->se_flags |= SE_SHUTDOWN;
1330		kill(sp->se_process, SIGHUP);
1331	}
1332
1333	/* terminate the accounting process */
1334	acct(NULL);
1335
1336	/* NB: should send a message to the session logger to avoid blocking. */
1337	logwtmp("~", "shutdown", "");
1338
1339	if (access(_PATH_RUNCOM, R_OK) != -1) {
1340		pid_t pid;
1341		struct sigaction sa;
1342
1343		switch ((pid = fork())) {
1344		case -1:
1345			break;
1346		case 0:
1347
1348			memset(&sa, 0, sizeof sa);
1349			sigemptyset(&sa.sa_mask);
1350			sa.sa_flags = 0;
1351			sa.sa_handler = SIG_IGN;
1352			(void) sigaction(SIGTSTP, &sa, NULL);
1353			(void) sigaction(SIGHUP, &sa, NULL);
1354
1355			setctty(_PATH_CONSOLE);
1356
1357			sigprocmask(SIG_SETMASK, &sa.sa_mask, NULL);
1358
1359			execl(_PATH_BSHELL, "sh", _PATH_RUNCOM, "shutdown",
1360			    (char *)NULL);
1361			stall("can't exec %s for %s %s: %m", _PATH_BSHELL,
1362			    _PATH_RUNCOM, "shutdown");
1363			_exit(1);
1364		default:
1365			waitpid(pid, &status, 0);
1366			if (WIFEXITED(status) && WEXITSTATUS(status) == 2)
1367				death_howto |= RB_POWERDOWN;
1368		}
1369	}
1370
1371	for (i = 0; i < 3; ++i) {
1372		if (kill(-1, death_sigs[i]) == -1 && errno == ESRCH)
1373			goto die;
1374
1375		clang = 0;
1376		alarm(DEATH_WATCH);
1377		do {
1378			if ((pid = waitpid(-1, NULL, 0)) != -1)
1379				collect_child(pid);
1380		} while (clang == 0 && errno != ECHILD);
1381
1382		if (errno == ECHILD)
1383			goto die;
1384	}
1385
1386	warning("some processes would not die; ps axl advised");
1387
1388die:
1389	reboot(death_howto);
1390
1391	/* ... and if that fails.. oh well */
1392	return (state_func_t) single_user;
1393}
1394
1395/*
1396 * Bring the system down to single user.
1397 */
1398state_func_t
1399death(void)
1400{
1401	session_t *sp;
1402	int i;
1403	pid_t pid;
1404	static const int death_sigs[3] = { SIGHUP, SIGTERM, SIGKILL };
1405
1406	/* terminate the accounting process */
1407	acct(NULL);
1408
1409	for (sp = sessions; sp; sp = sp->se_next)
1410		sp->se_flags |= SE_SHUTDOWN;
1411
1412	/* NB: should send a message to the session logger to avoid blocking. */
1413	logwtmp("~", "shutdown", "");
1414
1415	for (i = 0; i < 3; ++i) {
1416		if (kill(-1, death_sigs[i]) == -1 && errno == ESRCH)
1417			return (state_func_t) single_user;
1418
1419		clang = 0;
1420		alarm(DEATH_WATCH);
1421		do {
1422			if ((pid = waitpid(-1, NULL, 0)) != -1)
1423				collect_child(pid);
1424		} while (clang == 0 && errno != ECHILD);
1425
1426		if (errno == ECHILD)
1427			return (state_func_t) single_user;
1428	}
1429
1430	warning("some processes would not die; ps axl advised");
1431
1432	return (state_func_t) single_user;
1433}
1434
1435#ifdef LOGIN_CAP
1436void
1437setprocresources(char *class)
1438{
1439	login_cap_t *lc;
1440
1441	if ((lc = login_getclass(class)) != NULL) {
1442		setusercontext(lc, NULL, 0,
1443		    LOGIN_SETPRIORITY|LOGIN_SETRESOURCES|LOGIN_SETUMASK);
1444		login_close(lc);
1445	}
1446}
1447#endif
1448