init.c revision 1.60 
1/*	$OpenBSD: init.c,v 1.60 2016/08/27 01:55:30 guenther 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/reboot.h>
38#include <sys/sysctl.h>
39#include <sys/time.h>
40#include <sys/wait.h>
41#include <machine/cpu.h>
42
43#include <db.h>
44#include <err.h>
45#include <errno.h>
46#include <fcntl.h>
47#include <signal.h>
48#include <stdarg.h>
49#include <stdio.h>
50#include <stdlib.h>
51#include <string.h>
52#include <syslog.h>
53#include <time.h>
54#include <ttyent.h>
55#include <unistd.h>
56#include <util.h>
57
58#ifdef SECURE
59#include <pwd.h>
60#endif
61
62#ifdef LOGIN_CAP
63#include <login_cap.h>
64#endif
65
66#include "pathnames.h"
67
68/*
69 * Sleep times; used to prevent thrashing.
70 */
71#define	GETTY_SPACING		 5	/* N secs minimum getty spacing */
72#define	GETTY_SLEEP		30	/* sleep N secs after spacing problem */
73#define	WINDOW_WAIT		 3	/* wait N secs after starting window */
74#define	STALL_TIMEOUT		30	/* wait N secs after warning */
75#define	DEATH_WATCH		10	/* wait N secs for procs to die */
76
77/*
78 * User-based resource limits.
79 */
80#define RESOURCE_RC		"daemon"
81#define RESOURCE_WINDOW		"default"
82#define RESOURCE_GETTY		"default"
83
84#ifndef DEFAULT_STATE
85#define DEFAULT_STATE		runcom
86#endif
87
88void handle(sig_t, ...);
89void delset(sigset_t *, ...);
90
91void stall(char *, ...);
92void warning(char *, ...);
93void emergency(char *, ...);
94void disaster(int);
95void badsys(int);
96
97typedef enum {
98	invalid_state,
99	single_user,
100	runcom,
101	read_ttys,
102	multi_user,
103	clean_ttys,
104	catatonia,
105	death,
106	do_reboot,
107	hard_death,
108	nice_death
109} state_t;
110typedef state_t (*state_func_t)(void);
111
112state_t f_single_user(void);
113state_t f_runcom(void);
114state_t f_read_ttys(void);
115state_t f_multi_user(void);
116state_t f_clean_ttys(void);
117state_t f_catatonia(void);
118state_t f_death(void);
119state_t f_do_reboot(void);
120state_t f_hard_death(void);
121state_t f_nice_death(void);
122
123state_func_t state_funcs[] = {
124	NULL,
125	f_single_user,
126	f_runcom,
127	f_read_ttys,
128	f_multi_user,
129	f_clean_ttys,
130	f_catatonia,
131	f_death,
132	f_do_reboot,
133	f_hard_death,
134	f_nice_death
135};
136
137enum { AUTOBOOT, FASTBOOT } runcom_mode = AUTOBOOT;
138
139void transition(state_t);
140volatile sig_atomic_t requested_transition = DEFAULT_STATE;
141
142void setctty(char *);
143
144typedef struct init_session {
145	int	se_index;		/* index of entry in ttys file */
146	pid_t	se_process;		/* controlling process */
147	time_t	se_started;		/* used to avoid thrashing */
148	int	se_flags;		/* status of session */
149#define	SE_SHUTDOWN	0x1		/* session won't be restarted */
150#define	SE_PRESENT	0x2		/* session is in /etc/ttys */
151#define	SE_DEVEXISTS	0x4		/* open does not result in ENODEV */
152	char	*se_device;		/* filename of port */
153	char	*se_getty;		/* what to run on that port */
154	char	**se_getty_argv;	/* pre-parsed argument array */
155	char	*se_window;		/* window system (started only once) */
156	char	**se_window_argv;	/* pre-parsed argument array */
157	struct	init_session *se_prev;
158	struct	init_session *se_next;
159} session_t;
160
161void free_session(session_t *);
162session_t *new_session(session_t *, int, struct ttyent *);
163session_t *sessions;
164
165char **construct_argv(char *);
166void start_window_system(session_t *);
167void collect_child(pid_t);
168pid_t start_getty(session_t *);
169void transition_handler(int);
170void alrm_handler(int);
171void setsecuritylevel(int);
172int getsecuritylevel(void);
173int setupargv(session_t *, struct ttyent *);
174int clang;
175
176#ifdef LOGIN_CAP
177void setprocresources(char *);
178#else
179#define setprocresources(p)
180#endif
181
182void clear_session_logs(session_t *);
183
184int start_session_db(void);
185void add_session(session_t *);
186void del_session(session_t *);
187session_t *find_session(pid_t);
188DB *session_db;
189
190/*
191 * The mother of all processes.
192 */
193int
194main(int argc, char *argv[])
195{
196	int c, fd;
197	struct sigaction sa;
198	sigset_t mask;
199
200	/* Dispose of random users. */
201	if (getuid() != 0) {
202		(void)fprintf(stderr, "init: %s\n", strerror(EPERM));
203		exit (1);
204	}
205
206	/* System V users like to reexec init. */
207	if (getpid() != 1) {
208		(void)fprintf(stderr, "init: already running\n");
209		exit (1);
210	}
211
212	/*
213	 * Paranoia.
214	 */
215	if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
216		(void)dup2(fd, STDIN_FILENO);
217		(void)dup2(fd, STDOUT_FILENO);
218		(void)dup2(fd, STDERR_FILENO);
219		if (fd > 2)
220			(void)close(fd);
221	}
222
223	/*
224	 * Note that this does NOT open a file...
225	 * Does 'init' deserve its own facility number?
226	 */
227	openlog("init", LOG_CONS|LOG_ODELAY, LOG_AUTH);
228
229	/*
230	 * Create an initial session.
231	 */
232	if (setsid() < 0)
233		warning("initial setsid() failed: %m");
234
235	/*
236	 * Establish an initial user so that programs running
237	 * single user do not freak out and die (like passwd).
238	 */
239	if (setlogin("root") < 0)
240		warning("setlogin() failed: %m");
241
242	/*
243	 * This code assumes that we always get arguments through flags,
244	 * never through bits set in some random machine register.
245	 */
246	while ((c = getopt(argc, argv, "sf")) != -1)
247		switch (c) {
248		case 's':
249			requested_transition = single_user;
250			break;
251		case 'f':
252			runcom_mode = FASTBOOT;
253			break;
254		default:
255			warning("unrecognized flag '-%c'", c);
256			break;
257		}
258
259	if (optind != argc)
260		warning("ignoring excess arguments");
261
262	/*
263	 * We catch or block signals rather than ignore them,
264	 * so that they get reset on exec.
265	 */
266	handle(badsys, SIGSYS, 0);
267	handle(disaster, SIGABRT, SIGFPE, SIGILL, SIGSEGV,
268	    SIGBUS, SIGXCPU, SIGXFSZ, 0);
269	handle(transition_handler, SIGHUP, SIGINT, SIGTERM, SIGTSTP,
270            SIGUSR1, SIGUSR2, 0);
271	handle(alrm_handler, SIGALRM, 0);
272	sigfillset(&mask);
273	delset(&mask, SIGABRT, SIGFPE, SIGILL, SIGSEGV, SIGBUS, SIGSYS,
274	    SIGXCPU, SIGXFSZ, SIGHUP, SIGINT, SIGTERM, SIGUSR1, SIGUSR2,
275	    SIGTSTP, SIGALRM, 0);
276	sigprocmask(SIG_SETMASK, &mask, NULL);
277	memset(&sa, 0, sizeof sa);
278	sigemptyset(&sa.sa_mask);
279	sa.sa_flags = 0;
280	sa.sa_handler = SIG_IGN;
281	(void) sigaction(SIGTTIN, &sa, NULL);
282	(void) sigaction(SIGTTOU, &sa, NULL);
283
284	/*
285	 * Start the state machine.
286	 */
287	transition(requested_transition);
288
289	/*
290	 * Should never reach here.
291	 */
292	exit(1);
293}
294
295/*
296 * Associate a function with a signal handler.
297 */
298void
299handle(sig_t handler, ...)
300{
301	int sig;
302	struct sigaction sa;
303	sigset_t mask_everything;
304	va_list ap;
305
306	va_start(ap, handler);
307
308	memset(&sa, 0, sizeof sa);
309	sa.sa_handler = handler;
310	sigfillset(&mask_everything);
311
312	while ((sig = va_arg(ap, int))) {
313		sa.sa_mask = mask_everything;
314		/* XXX SA_RESTART? */
315		sa.sa_flags = sig == SIGCHLD ? SA_NOCLDSTOP : 0;
316		sigaction(sig, &sa, NULL);
317	}
318	va_end(ap);
319}
320
321/*
322 * Delete a set of signals from a mask.
323 */
324void
325delset(sigset_t *maskp, ...)
326{
327	int sig;
328	va_list ap;
329
330	va_start(ap, maskp);
331	while ((sig = va_arg(ap, int)))
332		sigdelset(maskp, sig);
333	va_end(ap);
334}
335
336/*
337 * Log a message and sleep for a while (to give someone an opportunity
338 * to read it and to save log or hardcopy output if the problem is chronic).
339 * NB: should send a message to the session logger to avoid blocking.
340 */
341void
342stall(char *message, ...)
343{
344	va_list ap;
345
346	va_start(ap, message);
347	vsyslog(LOG_ALERT, message, ap);
348	va_end(ap);
349	closelog();
350	sleep(STALL_TIMEOUT);
351}
352
353/*
354 * Like stall(), but doesn't sleep.
355 * If cpp had variadic macros, the two functions could be #defines for another.
356 * NB: should send a message to the session logger to avoid blocking.
357 */
358void
359warning(char *message, ...)
360{
361	va_list ap;
362
363	va_start(ap, message);
364	vsyslog(LOG_ALERT, message, ap);
365	va_end(ap);
366	closelog();
367}
368
369/*
370 * Log an emergency message.
371 * NB: should send a message to the session logger to avoid blocking.
372 */
373void
374emergency(char *message, ...)
375{
376	struct syslog_data sdata = SYSLOG_DATA_INIT;
377	va_list ap;
378
379	va_start(ap, message);
380	vsyslog_r(LOG_EMERG, &sdata, message, ap);
381	va_end(ap);
382}
383
384/*
385 * Catch a SIGSYS signal.
386 *
387 * These may arise if a system does not support sysctl.
388 * We tolerate up to 25 of these, then throw in the towel.
389 */
390void
391badsys(int sig)
392{
393	static int badcount = 0;
394
395	if (badcount++ < 25)
396		return;
397	disaster(sig);
398}
399
400/*
401 * Catch an unexpected signal.
402 */
403void
404disaster(int sig)
405{
406	emergency("fatal signal: %s", strsignal(sig));
407
408	sleep(STALL_TIMEOUT);
409	_exit(sig);		/* reboot */
410}
411
412/*
413 * Get the security level of the kernel.
414 */
415int
416getsecuritylevel(void)
417{
418#ifdef KERN_SECURELVL
419	int name[2], curlevel;
420	size_t len;
421
422	name[0] = CTL_KERN;
423	name[1] = KERN_SECURELVL;
424	len = sizeof curlevel;
425	if (sysctl(name, 2, &curlevel, &len, NULL, 0) == -1) {
426		emergency("cannot get kernel security level: %s",
427		    strerror(errno));
428		return (-1);
429	}
430	return (curlevel);
431#else
432	return (-1);
433#endif
434}
435
436/*
437 * Set the security level of the kernel.
438 */
439void
440setsecuritylevel(int newlevel)
441{
442#ifdef KERN_SECURELVL
443	int name[2], curlevel;
444
445	curlevel = getsecuritylevel();
446	if (newlevel == curlevel)
447		return;
448	name[0] = CTL_KERN;
449	name[1] = KERN_SECURELVL;
450	if (sysctl(name, 2, NULL, NULL, &newlevel, sizeof newlevel) == -1) {
451		emergency(
452		    "cannot change kernel security level from %d to %d: %s",
453		    curlevel, newlevel, strerror(errno));
454		return;
455	}
456#ifdef SECURE
457	warning("kernel security level changed from %d to %d",
458	    curlevel, newlevel);
459#endif
460#endif
461}
462
463/*
464 * Change states in the finite state machine.
465 * The initial state is passed as an argument.
466 */
467void
468transition(state_t s)
469{
470	for (;;)
471		s = (*state_funcs[s])();
472}
473
474/*
475 * Close out the accounting files for a login session.
476 * NB: should send a message to the session logger to avoid blocking.
477 */
478void
479clear_session_logs(session_t *sp)
480{
481	char *line = sp->se_device + sizeof(_PATH_DEV) - 1;
482
483	if (logout(line))
484		logwtmp(line, "", "");
485}
486
487/*
488 * Start a session and allocate a controlling terminal.
489 * Only called by children of init after forking.
490 */
491void
492setctty(char *name)
493{
494	int fd;
495
496	(void) revoke(name);
497	sleep(2);			/* leave DTR low */
498	if ((fd = open(name, O_RDWR)) == -1) {
499		stall("can't open %s: %m", name);
500		_exit(1);
501	}
502	if (login_tty(fd) == -1) {
503		stall("can't get %s for controlling terminal: %m", name);
504		_exit(1);
505	}
506}
507
508/*
509 * Bring the system up single user.
510 */
511state_t
512f_single_user(void)
513{
514	pid_t pid, wpid;
515	int status;
516	sigset_t mask;
517	char shell[PATH_MAX];		/* Allocate space here */
518	char name[PATH_MAX];		/* Name (argv[0]) of shell */
519	char *argv[2];
520#ifdef SECURE
521	struct ttyent *typ;
522	struct passwd *pp;
523	static const char banner[] =
524		"Enter root password, or ^D to go multi-user\n";
525	char *clear;
526#endif
527
528	/* Init shell and name */
529	strlcpy(shell, _PATH_BSHELL, sizeof shell);
530	strlcpy(name, "-sh", sizeof name);
531
532	/*
533	 * If the kernel is in secure mode, downgrade it to insecure mode.
534	 */
535	if (getsecuritylevel() > 0)
536		setsecuritylevel(0);
537
538	if ((pid = fork()) == 0) {
539		/*
540		 * Start the single user session.
541		 */
542		setctty(_PATH_CONSOLE);
543
544#ifdef SECURE
545		/*
546		 * Check the root password.
547		 * We don't care if the console is 'on' by default;
548		 * it's the only tty that can be 'off' and 'secure'.
549		 */
550		typ = getttynam("console");
551		pp = getpwnam_shadow("root");
552		if (typ && (typ->ty_status & TTY_SECURE) == 0 && pp &&
553		    *pp->pw_passwd) {
554			write(STDERR_FILENO, banner, sizeof banner - 1);
555			for (;;) {
556				int ok = 0;
557				clear = getpass("Password:");
558				if (clear == NULL || *clear == '\0')
559					_exit(0);
560				if (crypt_checkpass(clear, pp->pw_passwd) == 0)
561					ok = 1;
562				memset(clear, 0, strlen(clear));
563				if (ok)
564					break;
565				warning("single-user login failed\n");
566			}
567		}
568		endttyent();
569		endpwent();
570#endif /* SECURE */
571
572#ifdef DEBUGSHELL
573		{
574			char altshell[128], *cp = altshell;
575			int num;
576
577#define	SHREQUEST \
578	"Enter pathname of shell or RETURN for sh: "
579
580			(void)write(STDERR_FILENO,
581			    SHREQUEST, sizeof(SHREQUEST) - 1);
582			while ((num = read(STDIN_FILENO, cp, 1)) != -1 &&
583			    num != 0 && *cp != '\n' && cp < &altshell[127])
584				cp++;
585			*cp = '\0';
586
587			/* Copy in alternate shell */
588			if (altshell[0] != '\0'){
589				char *p;
590
591				/* Binary to exec */
592				strlcpy(shell, altshell, sizeof shell);
593
594				/* argv[0] */
595				p = strrchr(altshell, '/');
596				if(p == NULL) p = altshell;
597				else p++;
598
599				name[0] = '-';
600				strlcpy(&name[1], p, sizeof name -1);
601			}
602		}
603#endif /* DEBUGSHELL */
604
605		/*
606		 * Unblock signals.
607		 * We catch all the interesting ones,
608		 * and those are reset to SIG_DFL on exec.
609		 */
610		sigemptyset(&mask);
611		sigprocmask(SIG_SETMASK, &mask, NULL);
612
613		/*
614		 * Fire off a shell.
615		 * If the default one doesn't work, try the Bourne shell.
616		 */
617		argv[0] = name;
618		argv[1] = NULL;
619		setenv("PATH", _PATH_STDPATH, 1);
620		execv(shell, argv);
621		emergency("can't exec %s for single user: %m", shell);
622
623		argv[0] = "-sh";
624		argv[1] = NULL;
625		execv(_PATH_BSHELL, argv);
626		emergency("can't exec %s for single user: %m", _PATH_BSHELL);
627		sleep(STALL_TIMEOUT);
628		_exit(1);
629	}
630
631	if (pid == -1) {
632		/*
633		 * We are seriously hosed.  Do our best.
634		 */
635		emergency("can't fork single-user shell, trying again");
636		while (waitpid(-1, NULL, WNOHANG) > 0)
637			continue;
638		return single_user;
639	}
640
641	requested_transition = 0;
642	do {
643		if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1)
644			collect_child(wpid);
645		if (wpid == -1) {
646			if (errno == EINTR)
647				continue;
648			warning("wait for single-user shell failed: %m; restarting");
649			return single_user;
650		}
651		if (wpid == pid && WIFSTOPPED(status)) {
652			warning("init: shell stopped, restarting\n");
653			kill(pid, SIGCONT);
654			wpid = -1;
655		}
656	} while (wpid != pid && !requested_transition);
657
658	if (requested_transition)
659		return requested_transition;
660
661	if (!WIFEXITED(status)) {
662		if (WTERMSIG(status) == SIGKILL) {
663			/*
664			 *  reboot(8) killed shell?
665			 */
666			warning("single user shell terminated.");
667			sleep(STALL_TIMEOUT);
668			_exit(0);
669		} else {
670			warning("single user shell terminated, restarting");
671			return single_user;
672		}
673	}
674
675	runcom_mode = FASTBOOT;
676	return runcom;
677}
678
679/*
680 * Run the system startup script.
681 */
682state_t
683f_runcom(void)
684{
685	pid_t pid, wpid;
686	int status;
687	char *argv[4];
688	struct sigaction sa;
689
690	if ((pid = fork()) == 0) {
691		memset(&sa, 0, sizeof sa);
692		sigemptyset(&sa.sa_mask);
693		sa.sa_flags = 0;
694		sa.sa_handler = SIG_IGN;
695		(void) sigaction(SIGTSTP, &sa, NULL);
696		(void) sigaction(SIGHUP, &sa, NULL);
697
698		setctty(_PATH_CONSOLE);
699
700		argv[0] = "sh";
701		argv[1] = _PATH_RUNCOM;
702		argv[2] = runcom_mode == AUTOBOOT ? "autoboot" : NULL;
703		argv[3] = NULL;
704
705		sigprocmask(SIG_SETMASK, &sa.sa_mask, NULL);
706
707		setprocresources(RESOURCE_RC);
708
709		execv(_PATH_BSHELL, argv);
710		stall("can't exec %s for %s: %m", _PATH_BSHELL, _PATH_RUNCOM);
711		_exit(1);	/* force single user mode */
712	}
713
714	if (pid == -1) {
715		emergency("can't fork for %s on %s: %m",
716			_PATH_BSHELL, _PATH_RUNCOM);
717		while (waitpid(-1, NULL, WNOHANG) > 0)
718			continue;
719		sleep(STALL_TIMEOUT);
720		return single_user;
721	}
722
723	/*
724	 * Copied from single_user().  This is a bit paranoid.
725	 */
726	do {
727		if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1)
728			collect_child(wpid);
729		if (wpid == -1) {
730			if (errno == EINTR)
731				continue;
732			warning("wait for %s on %s failed: %m; going to single user mode",
733			    _PATH_BSHELL, _PATH_RUNCOM);
734			return single_user;
735		}
736		if (wpid == pid && WIFSTOPPED(status)) {
737			warning("init: %s on %s stopped, restarting\n",
738			    _PATH_BSHELL, _PATH_RUNCOM);
739			kill(pid, SIGCONT);
740			wpid = -1;
741		}
742	} while (wpid != pid);
743
744	if (WIFSIGNALED(status) && WTERMSIG(status) == SIGTERM &&
745	    requested_transition == catatonia) {
746		/* /etc/rc executed /sbin/reboot; wait for the end quietly */
747		sigset_t s;
748
749		sigfillset(&s);
750		for (;;)
751			sigsuspend(&s);
752	}
753
754	if (!WIFEXITED(status)) {
755		warning("%s on %s terminated abnormally, going to single user mode",
756		    _PATH_BSHELL, _PATH_RUNCOM);
757		return single_user;
758	}
759
760	if (WEXITSTATUS(status))
761		return single_user;
762
763	runcom_mode = AUTOBOOT;		/* the default */
764	/* NB: should send a message to the session logger to avoid blocking. */
765	logwtmp("~", "reboot", "");
766	return read_ttys;
767}
768
769/*
770 * Open the session database.
771 *
772 * NB: We could pass in the size here; is it necessary?
773 */
774int
775start_session_db(void)
776{
777	if (session_db && (*session_db->close)(session_db))
778		emergency("session database close: %s", strerror(errno));
779	if ((session_db = dbopen(NULL, O_RDWR, 0, DB_HASH, NULL)) == 0) {
780		emergency("session database open: %s", strerror(errno));
781		return (1);
782	}
783	return (0);
784}
785
786/*
787 * Add a new login session.
788 */
789void
790add_session(session_t *sp)
791{
792	DBT key;
793	DBT data;
794
795	key.data = &sp->se_process;
796	key.size = sizeof sp->se_process;
797	data.data = &sp;
798	data.size = sizeof sp;
799
800	if ((*session_db->put)(session_db, &key, &data, 0))
801		emergency("insert %d: %s", sp->se_process, strerror(errno));
802}
803
804/*
805 * Delete an old login session.
806 */
807void
808del_session(session_t *sp)
809{
810	DBT key;
811
812	key.data = &sp->se_process;
813	key.size = sizeof sp->se_process;
814
815	if ((*session_db->del)(session_db, &key, 0))
816		emergency("delete %d: %s", sp->se_process, strerror(errno));
817}
818
819/*
820 * Look up a login session by pid.
821 */
822session_t *
823find_session(pid_t pid)
824{
825	DBT key;
826	DBT data;
827	session_t *ret;
828
829	key.data = &pid;
830	key.size = sizeof pid;
831	if ((*session_db->get)(session_db, &key, &data, 0) != 0)
832		return (0);
833	memcpy(&ret, data.data, sizeof(ret));
834	return (ret);
835}
836
837/*
838 * Construct an argument vector from a command line.
839 */
840char **
841construct_argv(char *command)
842{
843	int argc = 0;
844	char **argv = calloc((strlen(command) + 1) / 2 + 1, sizeof (char *));
845	static const char separators[] = " \t";
846
847	if (argv == NULL)
848		return (0);
849
850	if ((argv[argc++] = strtok(command, separators)) == 0) {
851		free(argv);
852		return (0);
853	}
854	while ((argv[argc++] = strtok(NULL, separators)))
855		continue;
856	return (argv);
857}
858
859/*
860 * Deallocate a session descriptor.
861 */
862void
863free_session(session_t *sp)
864{
865	free(sp->se_device);
866	if (sp->se_getty) {
867		free(sp->se_getty);
868		free(sp->se_getty_argv);
869	}
870	if (sp->se_window) {
871		free(sp->se_window);
872		free(sp->se_window_argv);
873	}
874	free(sp);
875}
876
877/*
878 * Allocate a new session descriptor.
879 */
880session_t *
881new_session(session_t *sprev, int session_index, struct ttyent *typ)
882{
883	session_t *sp;
884
885	if ((typ->ty_status & TTY_ON) == 0 ||
886	    typ->ty_name == 0 ||
887	    typ->ty_getty == 0)
888		return (0);
889
890	sp = calloc(1, sizeof (session_t));
891	if (sp == NULL)
892		err(1, "calloc");
893
894	sp->se_flags = SE_PRESENT;
895	sp->se_index = session_index;
896
897	if (asprintf(&sp->se_device, "%s%s", _PATH_DEV, typ->ty_name) == -1)
898		err(1, "asprintf");
899
900	if (setupargv(sp, typ) == 0) {
901		free_session(sp);
902		return (0);
903	}
904
905	sp->se_next = NULL;
906	if (sprev == NULL) {
907		sessions = sp;
908		sp->se_prev = NULL;
909	} else {
910		sprev->se_next = sp;
911		sp->se_prev = sprev;
912	}
913
914	return (sp);
915}
916
917/*
918 * Calculate getty and if useful window argv vectors.
919 */
920int
921setupargv(session_t *sp, struct ttyent *typ)
922{
923	if (sp->se_getty) {
924		free(sp->se_getty);
925		free(sp->se_getty_argv);
926	}
927	if (asprintf(&sp->se_getty, "%s %s", typ->ty_getty, typ->ty_name) == -1)
928		err(1, "asprintf");
929	sp->se_getty_argv = construct_argv(sp->se_getty);
930	if (sp->se_getty_argv == 0) {
931		warning("can't parse getty for port %s", sp->se_device);
932		free(sp->se_getty);
933		sp->se_getty = NULL;
934		return (0);
935	}
936	if (typ->ty_window) {
937		free(sp->se_window);
938		sp->se_window = strdup(typ->ty_window);
939		if (sp->se_window == NULL) {
940			warning("can't allocate window");
941			return (0);
942		}
943		sp->se_window_argv = construct_argv(sp->se_window);
944		if (sp->se_window_argv == NULL) {
945			warning("can't parse window for port %s",
946			    sp->se_device);
947			free(sp->se_window);
948			sp->se_window = NULL;
949			return (0);
950		}
951	}
952	return (1);
953}
954
955/*
956 * Walk the list of ttys and create sessions for each active line.
957 */
958state_t
959f_read_ttys(void)
960{
961	int session_index = 0;
962	session_t *sp, *snext;
963	struct ttyent *typ;
964
965	/*
966	 * Destroy any previous session state.
967	 * There shouldn't be any, but just in case...
968	 */
969	for (sp = sessions; sp; sp = snext) {
970		if (sp->se_process)
971			clear_session_logs(sp);
972		snext = sp->se_next;
973		free_session(sp);
974	}
975	sessions = NULL;
976	if (start_session_db())
977		return single_user;
978
979	/*
980	 * Allocate a session entry for each active port.
981	 * Note that sp starts at 0.
982	 */
983	while ((typ = getttyent()))
984		if ((snext = new_session(sp, ++session_index, typ)))
985			sp = snext;
986
987	endttyent();
988
989	return multi_user;
990}
991
992/*
993 * Start a window system running.
994 */
995void
996start_window_system(session_t *sp)
997{
998	pid_t pid;
999	sigset_t mask;
1000
1001	if ((pid = fork()) == -1) {
1002		emergency("can't fork for window system on port %s: %m",
1003		    sp->se_device);
1004		/* hope that getty fails and we can try again */
1005		return;
1006	}
1007
1008	if (pid)
1009		return;
1010
1011	sigemptyset(&mask);
1012	sigprocmask(SIG_SETMASK, &mask, NULL);
1013
1014	if (setsid() < 0)
1015		emergency("setsid failed (window) %m");
1016
1017	setprocresources(RESOURCE_WINDOW);
1018
1019	execv(sp->se_window_argv[0], sp->se_window_argv);
1020	stall("can't exec window system '%s' for port %s: %m",
1021	    sp->se_window_argv[0], sp->se_device);
1022	_exit(1);
1023}
1024
1025/*
1026 * Start a login session running.
1027 * For first open, man-handle tty directly to determine if it
1028 * really exists. It is not efficient to spawn gettys on devices
1029 * that do not exist.
1030 */
1031pid_t
1032start_getty(session_t *sp)
1033{
1034	pid_t pid;
1035	sigset_t mask;
1036	time_t current_time = time(NULL);
1037	int p[2], new = 1;
1038
1039	if (sp->se_flags & SE_DEVEXISTS)
1040		new = 0;
1041
1042	if (new) {
1043		if (pipe(p) == -1)
1044			return (-1);
1045	}
1046
1047	/*
1048	 * fork(), not vfork() -- we can't afford to block.
1049	 */
1050	if ((pid = fork()) == -1) {
1051		emergency("can't fork for getty on port %s: %m", sp->se_device);
1052		return (-1);
1053	}
1054
1055	if (pid) {
1056		if (new) {
1057			char c;
1058
1059			close(p[1]);
1060			if (read(p[0], &c, 1) != 1) {
1061				close(p[0]);
1062				return (-1);
1063			}
1064			close(p[0]);
1065			if (c == '1')
1066				sp->se_flags |= SE_DEVEXISTS;
1067			else
1068				sp->se_flags |= SE_SHUTDOWN;
1069		}
1070		return (pid);
1071	}
1072	if (new) {
1073		int fd;
1074
1075		close(p[0]);
1076		fd = open(sp->se_device, O_RDONLY | O_NONBLOCK, 0666);
1077		if (fd == -1 && (errno == ENXIO || errno == ENOENT ||
1078		    errno == EISDIR)) {
1079			(void)write(p[1], "0", 1);
1080			close(p[1]);
1081			_exit(1);
1082		}
1083		(void)write(p[1], "1", 1);
1084		close(p[1]);
1085		close(fd);
1086		sleep(1);
1087	}
1088
1089	if (current_time > sp->se_started &&
1090	    current_time - sp->se_started < GETTY_SPACING) {
1091		warning("getty repeating too quickly on port %s, sleeping",
1092		    sp->se_device);
1093		sleep(GETTY_SLEEP);
1094	}
1095
1096	if (sp->se_window) {
1097		start_window_system(sp);
1098		sleep(WINDOW_WAIT);
1099	}
1100
1101	sigemptyset(&mask);
1102	sigprocmask(SIG_SETMASK, &mask, NULL);
1103
1104	setprocresources(RESOURCE_GETTY);
1105
1106	execv(sp->se_getty_argv[0], sp->se_getty_argv);
1107	stall("can't exec getty '%s' for port %s: %m",
1108	    sp->se_getty_argv[0], sp->se_device);
1109	_exit(1);
1110}
1111
1112/*
1113 * Collect exit status for a child.
1114 * If an exiting login, start a new login running.
1115 */
1116void
1117collect_child(pid_t pid)
1118{
1119	session_t *sp, *sprev, *snext;
1120
1121	if (sessions == NULL)
1122		return;
1123
1124	if ((sp = find_session(pid)) == NULL)
1125		return;
1126
1127	clear_session_logs(sp);
1128	login_fbtab(sp->se_device + sizeof(_PATH_DEV) - 1, 0, 0);
1129	del_session(sp);
1130	sp->se_process = 0;
1131
1132	if (sp->se_flags & SE_SHUTDOWN) {
1133		if ((sprev = sp->se_prev))
1134			sprev->se_next = sp->se_next;
1135		else
1136			sessions = sp->se_next;
1137		if ((snext = sp->se_next))
1138			snext->se_prev = sp->se_prev;
1139		free_session(sp);
1140		return;
1141	}
1142
1143	if ((pid = start_getty(sp)) == -1) {
1144		/* serious trouble */
1145		requested_transition = clean_ttys;
1146		return;
1147	}
1148
1149	sp->se_process = pid;
1150	sp->se_started = time(NULL);
1151	add_session(sp);
1152}
1153
1154/*
1155 * Catch a signal and request a state transition.
1156 */
1157void
1158transition_handler(int sig)
1159{
1160
1161	switch (sig) {
1162	case SIGHUP:
1163		requested_transition = clean_ttys;
1164		break;
1165	case SIGINT:
1166		requested_transition = do_reboot;
1167		break;
1168	case SIGTERM:
1169		requested_transition = death;
1170		break;
1171	case SIGUSR1:
1172		requested_transition = nice_death;
1173		break;
1174	case SIGUSR2:
1175		requested_transition = hard_death;
1176		break;
1177	case SIGTSTP:
1178		requested_transition = catatonia;
1179		break;
1180	default:
1181		requested_transition = 0;
1182		break;
1183	}
1184}
1185
1186/*
1187 * Take the system multiuser.
1188 */
1189state_t
1190f_multi_user(void)
1191{
1192	pid_t pid;
1193	session_t *sp;
1194
1195	/*
1196	 * If the administrator has not set the security level to -1
1197	 * to indicate that the kernel should not run multiuser in secure
1198	 * mode, and the run script has not set a higher level of security
1199	 * than level 1, then put the kernel into secure mode.
1200	 */
1201	if (requested_transition != catatonia) {
1202		if (getsecuritylevel() == 0)
1203			setsecuritylevel(1);
1204	}
1205
1206	requested_transition = 0;
1207
1208	for (sp = sessions; sp; sp = sp->se_next) {
1209		if (sp->se_process)
1210			continue;
1211		if ((pid = start_getty(sp)) == -1) {
1212			/* serious trouble */
1213			requested_transition = clean_ttys;
1214			break;
1215		}
1216		sp->se_process = pid;
1217		sp->se_started = time(NULL);
1218		add_session(sp);
1219	}
1220
1221	while (!requested_transition)
1222		if ((pid = waitpid(-1, NULL, 0)) != -1)
1223			collect_child(pid);
1224
1225	return requested_transition;
1226}
1227
1228/*
1229 * This is an n-squared algorithm.  We hope it isn't run often...
1230 */
1231state_t
1232f_clean_ttys(void)
1233{
1234	session_t *sp, *sprev;
1235	struct ttyent *typ;
1236	int session_index = 0;
1237	int devlen;
1238
1239	for (sp = sessions; sp; sp = sp->se_next)
1240		sp->se_flags &= ~SE_PRESENT;
1241
1242	devlen = sizeof(_PATH_DEV) - 1;
1243	while ((typ = getttyent())) {
1244		++session_index;
1245
1246		for (sprev = NULL, sp = sessions; sp; sprev = sp, sp = sp->se_next)
1247			if (strcmp(typ->ty_name, sp->se_device + devlen) == 0)
1248				break;
1249
1250		if (sp) {
1251			sp->se_flags |= SE_PRESENT;
1252			if (sp->se_index != session_index) {
1253				warning("port %s changed utmp index from %d to %d",
1254				    sp->se_device, sp->se_index,
1255				    session_index);
1256				sp->se_index = session_index;
1257			}
1258			if ((typ->ty_status & TTY_ON) == 0 ||
1259			    typ->ty_getty == 0) {
1260				sp->se_flags |= SE_SHUTDOWN;
1261				kill(sp->se_process, SIGHUP);
1262				continue;
1263			}
1264			sp->se_flags &= ~SE_SHUTDOWN;
1265			if (setupargv(sp, typ) == 0) {
1266				warning("can't parse getty for port %s",
1267				    sp->se_device);
1268				sp->se_flags |= SE_SHUTDOWN;
1269				kill(sp->se_process, SIGHUP);
1270			}
1271			continue;
1272		}
1273
1274		new_session(sprev, session_index, typ);
1275	}
1276
1277	endttyent();
1278
1279	for (sp = sessions; sp; sp = sp->se_next)
1280		if ((sp->se_flags & SE_PRESENT) == 0) {
1281			sp->se_flags |= SE_SHUTDOWN;
1282			kill(sp->se_process, SIGHUP);
1283		}
1284
1285	return multi_user;
1286}
1287
1288/*
1289 * Block further logins.
1290 */
1291state_t
1292f_catatonia(void)
1293{
1294	session_t *sp;
1295
1296	for (sp = sessions; sp; sp = sp->se_next)
1297		sp->se_flags |= SE_SHUTDOWN;
1298
1299	return multi_user;
1300}
1301
1302/*
1303 * Note SIGALRM.
1304 */
1305void
1306alrm_handler(int sig)
1307{
1308	clang = 1;
1309}
1310
1311int death_howto = RB_HALT;
1312
1313/*
1314 * Reboot the system.
1315 */
1316state_t
1317f_do_reboot(void)
1318{
1319	death_howto = RB_AUTOBOOT;
1320	return nice_death;
1321}
1322
1323/*
1324 * Bring the system down nicely, then we must powerdown because something
1325 * is very wrong.
1326 */
1327state_t
1328f_hard_death(void)
1329{
1330	death_howto |= RB_POWERDOWN;
1331	return nice_death;
1332}
1333
1334/*
1335 * Bring the system down to single user nicely, after run the shutdown script.
1336 */
1337state_t
1338f_nice_death(void)
1339{
1340	session_t *sp;
1341	int i;
1342	pid_t pid;
1343	static const int death_sigs[3] = { SIGHUP, SIGTERM, SIGKILL };
1344	int status;
1345
1346#ifdef CPU_LIDSUSPEND
1347	int lidsuspend_mib[] = {CTL_MACHDEP, CPU_LIDSUSPEND};
1348	int dontsuspend = 0;
1349
1350	if ((death_howto & RB_POWERDOWN) &&
1351	    (sysctl(lidsuspend_mib, 2, NULL, NULL, &dontsuspend,
1352		    sizeof(dontsuspend)) == -1) && (errno != EOPNOTSUPP))
1353			warning("cannot disable lid suspend");
1354#endif
1355
1356	for (sp = sessions; sp; sp = sp->se_next) {
1357		sp->se_flags &= ~SE_PRESENT;
1358		sp->se_flags |= SE_SHUTDOWN;
1359		kill(sp->se_process, SIGHUP);
1360	}
1361
1362	/* terminate the accounting process */
1363	acct(NULL);
1364
1365	/* NB: should send a message to the session logger to avoid blocking. */
1366	logwtmp("~", "shutdown", "");
1367
1368	if (access(_PATH_RUNCOM, R_OK) != -1) {
1369		struct sigaction sa;
1370
1371		switch ((pid = fork())) {
1372		case -1:
1373			break;
1374		case 0:
1375
1376			memset(&sa, 0, sizeof sa);
1377			sigemptyset(&sa.sa_mask);
1378			sa.sa_flags = 0;
1379			sa.sa_handler = SIG_IGN;
1380			(void) sigaction(SIGTSTP, &sa, NULL);
1381			(void) sigaction(SIGHUP, &sa, NULL);
1382
1383			setctty(_PATH_CONSOLE);
1384
1385			sigprocmask(SIG_SETMASK, &sa.sa_mask, NULL);
1386
1387			execl(_PATH_BSHELL, "sh", _PATH_RUNCOM, "shutdown",
1388			    (char *)NULL);
1389			stall("can't exec %s for %s %s: %m", _PATH_BSHELL,
1390			    _PATH_RUNCOM, "shutdown");
1391			_exit(1);
1392		default:
1393			waitpid(pid, &status, 0);
1394			if (WIFEXITED(status) && WEXITSTATUS(status) == 2)
1395				death_howto |= RB_POWERDOWN;
1396		}
1397	}
1398
1399	for (i = 0; i < 3; ++i) {
1400		if (kill(-1, death_sigs[i]) == -1 && errno == ESRCH)
1401			goto die;
1402
1403		clang = 0;
1404		alarm(DEATH_WATCH);
1405		do {
1406			if ((pid = waitpid(-1, NULL, 0)) != -1)
1407				collect_child(pid);
1408		} while (clang == 0 && errno != ECHILD);
1409
1410		if (errno == ECHILD)
1411			goto die;
1412	}
1413
1414	warning("some processes would not die; ps axl advised");
1415
1416die:
1417	reboot(death_howto);
1418
1419	/* ... and if that fails.. oh well */
1420	return single_user;
1421}
1422
1423/*
1424 * Bring the system down to single user.
1425 */
1426state_t
1427f_death(void)
1428{
1429	session_t *sp;
1430	int i;
1431	pid_t pid;
1432	static const int death_sigs[3] = { SIGHUP, SIGTERM, SIGKILL };
1433
1434	/* terminate the accounting process */
1435	acct(NULL);
1436
1437	for (sp = sessions; sp; sp = sp->se_next)
1438		sp->se_flags |= SE_SHUTDOWN;
1439
1440	/* NB: should send a message to the session logger to avoid blocking. */
1441	logwtmp("~", "shutdown", "");
1442
1443	for (i = 0; i < 3; ++i) {
1444		if (kill(-1, death_sigs[i]) == -1 && errno == ESRCH)
1445			return single_user;
1446
1447		clang = 0;
1448		alarm(DEATH_WATCH);
1449		do {
1450			if ((pid = waitpid(-1, NULL, 0)) != -1)
1451				collect_child(pid);
1452		} while (clang == 0 && errno != ECHILD);
1453
1454		if (errno == ECHILD)
1455			return single_user;
1456	}
1457
1458	warning("some processes would not die; ps axl advised");
1459
1460	return single_user;
1461}
1462
1463#ifdef LOGIN_CAP
1464void
1465setprocresources(char *class)
1466{
1467	login_cap_t *lc;
1468
1469	if ((lc = login_getclass(class)) != NULL) {
1470		setusercontext(lc, NULL, 0,
1471		    LOGIN_SETPRIORITY|LOGIN_SETRESOURCES|LOGIN_SETUMASK);
1472		login_close(lc);
1473	}
1474}
1475#endif
1476