init.c revision 1.64 
1/*	$OpenBSD: init.c,v 1.64 2017/05/03 09:51:39 mestre 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/tree.h>
41#include <sys/wait.h>
42#include <machine/cpu.h>
43
44#include <err.h>
45#include <errno.h>
46#include <fcntl.h>
47#include <limits.h>
48#include <signal.h>
49#include <stdarg.h>
50#include <stdio.h>
51#include <stdlib.h>
52#include <string.h>
53#include <syslog.h>
54#include <time.h>
55#include <ttyent.h>
56#include <unistd.h>
57#include <util.h>
58
59#ifdef SECURE
60#include <pwd.h>
61#include <readpassphrase.h>
62#endif
63
64#ifdef LOGIN_CAP
65#include <login_cap.h>
66#endif
67
68#include "pathnames.h"
69
70/*
71 * Sleep times; used to prevent thrashing.
72 */
73#define	GETTY_SPACING		 5	/* N secs minimum getty spacing */
74#define	GETTY_SLEEP		30	/* sleep N secs after spacing problem */
75#define	WINDOW_WAIT		 3	/* wait N secs after starting window */
76#define	STALL_TIMEOUT		30	/* wait N secs after warning */
77#define	DEATH_WATCH		10	/* wait N secs for procs to die */
78
79/*
80 * User-based resource limits.
81 */
82#define RESOURCE_RC		"daemon"
83#define RESOURCE_WINDOW		"default"
84#define RESOURCE_GETTY		"default"
85
86#ifndef DEFAULT_STATE
87#define DEFAULT_STATE		runcom
88#endif
89
90void handle(sig_t, ...);
91void delset(sigset_t *, ...);
92
93void stall(char *, ...);
94void warning(char *, ...);
95void emergency(char *, ...);
96void disaster(int);
97void badsys(int);
98
99typedef enum {
100	invalid_state,
101	single_user,
102	runcom,
103	read_ttys,
104	multi_user,
105	clean_ttys,
106	catatonia,
107	death,
108	do_reboot,
109	hard_death,
110	nice_death
111} state_t;
112typedef state_t (*state_func_t)(void);
113
114state_t f_single_user(void);
115state_t f_runcom(void);
116state_t f_read_ttys(void);
117state_t f_multi_user(void);
118state_t f_clean_ttys(void);
119state_t f_catatonia(void);
120state_t f_death(void);
121state_t f_do_reboot(void);
122state_t f_hard_death(void);
123state_t f_nice_death(void);
124
125state_func_t state_funcs[] = {
126	NULL,
127	f_single_user,
128	f_runcom,
129	f_read_ttys,
130	f_multi_user,
131	f_clean_ttys,
132	f_catatonia,
133	f_death,
134	f_do_reboot,
135	f_hard_death,
136	f_nice_death
137};
138
139enum { AUTOBOOT, FASTBOOT } runcom_mode = AUTOBOOT;
140
141void transition(state_t);
142volatile sig_atomic_t requested_transition = DEFAULT_STATE;
143
144void setctty(char *);
145
146typedef struct init_session {
147	int	se_index;		/* index of entry in ttys file */
148	pid_t	se_process;		/* controlling process */
149	time_t	se_started;		/* used to avoid thrashing */
150	int	se_flags;		/* status of session */
151#define	SE_SHUTDOWN	0x1		/* session won't be restarted */
152#define	SE_PRESENT	0x2		/* session is in /etc/ttys */
153#define	SE_DEVEXISTS	0x4		/* open does not result in ENODEV */
154	char	*se_device;		/* filename of port */
155	char	*se_getty;		/* what to run on that port */
156	char	**se_getty_argv;	/* pre-parsed argument array */
157	char	*se_window;		/* window system (started only once) */
158	char	**se_window_argv;	/* pre-parsed argument array */
159	struct	init_session *se_prev;
160	struct	init_session *se_next;
161	RB_ENTRY(init_session) se_entry;
162} session_t;
163
164static int cmp_sessions(session_t *, session_t *);
165RB_HEAD(session_tree, init_session) session_tree = RB_INITIALIZER(session_tree);
166RB_PROTOTYPE(session_tree, init_session, se_entry, cmp_sessions);
167RB_GENERATE(session_tree, init_session, se_entry, cmp_sessions);
168
169void free_session(session_t *);
170session_t *new_session(session_t *, int, struct ttyent *);
171session_t *sessions;
172
173char **construct_argv(char *);
174void start_window_system(session_t *);
175void collect_child(pid_t);
176pid_t start_getty(session_t *);
177void transition_handler(int);
178void alrm_handler(int);
179void setsecuritylevel(int);
180int getsecuritylevel(void);
181int setupargv(session_t *, struct ttyent *);
182int clang;
183
184#ifdef LOGIN_CAP
185void setprocresources(char *);
186#else
187#define setprocresources(p)
188#endif
189
190void clear_session_logs(session_t *);
191
192void add_session(session_t *);
193void del_session(session_t *);
194session_t *find_session(pid_t);
195
196/*
197 * The mother of all processes.
198 */
199int
200main(int argc, char *argv[])
201{
202	int c, fd;
203	struct sigaction sa;
204	sigset_t mask;
205
206	/* Dispose of random users. */
207	if (getuid() != 0) {
208		(void)fprintf(stderr, "init: %s\n", strerror(EPERM));
209		exit (1);
210	}
211
212	/* System V users like to reexec init. */
213	if (getpid() != 1) {
214		(void)fprintf(stderr, "init: already running\n");
215		exit (1);
216	}
217
218	/*
219	 * Paranoia.
220	 */
221	if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
222		(void)dup2(fd, STDIN_FILENO);
223		(void)dup2(fd, STDOUT_FILENO);
224		(void)dup2(fd, STDERR_FILENO);
225		if (fd > 2)
226			(void)close(fd);
227	}
228
229	/*
230	 * Note that this does NOT open a file...
231	 * Does 'init' deserve its own facility number?
232	 */
233	openlog("init", LOG_CONS|LOG_ODELAY, LOG_AUTH);
234
235	/*
236	 * Create an initial session.
237	 */
238	if (setsid() < 0)
239		warning("initial setsid() failed: %m");
240
241	/*
242	 * Establish an initial user so that programs running
243	 * single user do not freak out and die (like passwd).
244	 */
245	if (setlogin("root") < 0)
246		warning("setlogin() failed: %m");
247
248	/*
249	 * This code assumes that we always get arguments through flags,
250	 * never through bits set in some random machine register.
251	 */
252	while ((c = getopt(argc, argv, "sf")) != -1)
253		switch (c) {
254		case 's':
255			requested_transition = single_user;
256			break;
257		case 'f':
258			runcom_mode = FASTBOOT;
259			break;
260		default:
261			warning("unrecognized flag '-%c'", c);
262			break;
263		}
264
265	if (optind != argc)
266		warning("ignoring excess arguments");
267
268	/*
269	 * We catch or block signals rather than ignore them,
270	 * so that they get reset on exec.
271	 */
272	handle(badsys, SIGSYS, 0);
273	handle(disaster, SIGABRT, SIGFPE, SIGILL, SIGSEGV,
274	    SIGBUS, SIGXCPU, SIGXFSZ, 0);
275	handle(transition_handler, SIGHUP, SIGINT, SIGTERM, SIGTSTP,
276            SIGUSR1, SIGUSR2, 0);
277	handle(alrm_handler, SIGALRM, 0);
278	sigfillset(&mask);
279	delset(&mask, SIGABRT, SIGFPE, SIGILL, SIGSEGV, SIGBUS, SIGSYS,
280	    SIGXCPU, SIGXFSZ, SIGHUP, SIGINT, SIGTERM, SIGUSR1, SIGUSR2,
281	    SIGTSTP, SIGALRM, 0);
282	sigprocmask(SIG_SETMASK, &mask, NULL);
283	memset(&sa, 0, sizeof sa);
284	sigemptyset(&sa.sa_mask);
285	sa.sa_flags = 0;
286	sa.sa_handler = SIG_IGN;
287	(void) sigaction(SIGTTIN, &sa, NULL);
288	(void) sigaction(SIGTTOU, &sa, NULL);
289
290	/*
291	 * Start the state machine.
292	 */
293	transition(requested_transition);
294
295	/*
296	 * Should never reach here.
297	 */
298	exit(1);
299}
300
301/*
302 * Associate a function with a signal handler.
303 */
304void
305handle(sig_t handler, ...)
306{
307	int sig;
308	struct sigaction sa;
309	sigset_t mask_everything;
310	va_list ap;
311
312	va_start(ap, handler);
313
314	memset(&sa, 0, sizeof sa);
315	sa.sa_handler = handler;
316	sigfillset(&mask_everything);
317
318	while ((sig = va_arg(ap, int))) {
319		sa.sa_mask = mask_everything;
320		/* XXX SA_RESTART? */
321		sa.sa_flags = sig == SIGCHLD ? SA_NOCLDSTOP : 0;
322		sigaction(sig, &sa, NULL);
323	}
324	va_end(ap);
325}
326
327/*
328 * Delete a set of signals from a mask.
329 */
330void
331delset(sigset_t *maskp, ...)
332{
333	int sig;
334	va_list ap;
335
336	va_start(ap, maskp);
337	while ((sig = va_arg(ap, int)))
338		sigdelset(maskp, sig);
339	va_end(ap);
340}
341
342/*
343 * Log a message and sleep for a while (to give someone an opportunity
344 * to read it and to save log or hardcopy output if the problem is chronic).
345 * NB: should send a message to the session logger to avoid blocking.
346 */
347void
348stall(char *message, ...)
349{
350	va_list ap;
351
352	va_start(ap, message);
353	vsyslog(LOG_ALERT, message, ap);
354	va_end(ap);
355	closelog();
356	sleep(STALL_TIMEOUT);
357}
358
359/*
360 * Like stall(), but doesn't sleep.
361 * If cpp had variadic macros, the two functions could be #defines for another.
362 * NB: should send a message to the session logger to avoid blocking.
363 */
364void
365warning(char *message, ...)
366{
367	va_list ap;
368
369	va_start(ap, message);
370	vsyslog(LOG_ALERT, message, ap);
371	va_end(ap);
372	closelog();
373}
374
375/*
376 * Log an emergency message.
377 * NB: should send a message to the session logger to avoid blocking.
378 */
379void
380emergency(char *message, ...)
381{
382	struct syslog_data sdata = SYSLOG_DATA_INIT;
383	va_list ap;
384
385	va_start(ap, message);
386	vsyslog_r(LOG_EMERG, &sdata, message, ap);
387	va_end(ap);
388}
389
390/*
391 * Catch a SIGSYS signal.
392 *
393 * These may arise if a system does not support sysctl.
394 * We tolerate up to 25 of these, then throw in the towel.
395 */
396void
397badsys(int sig)
398{
399	static int badcount = 0;
400
401	if (badcount++ < 25)
402		return;
403	disaster(sig);
404}
405
406/*
407 * Catch an unexpected signal.
408 */
409void
410disaster(int sig)
411{
412	emergency("fatal signal: %s", strsignal(sig));
413
414	sleep(STALL_TIMEOUT);
415	_exit(sig);		/* reboot */
416}
417
418/*
419 * Get the security level of the kernel.
420 */
421int
422getsecuritylevel(void)
423{
424#ifdef KERN_SECURELVL
425	int name[2], curlevel;
426	size_t len;
427
428	name[0] = CTL_KERN;
429	name[1] = KERN_SECURELVL;
430	len = sizeof curlevel;
431	if (sysctl(name, 2, &curlevel, &len, NULL, 0) == -1) {
432		emergency("cannot get kernel security level: %s",
433		    strerror(errno));
434		return (-1);
435	}
436	return (curlevel);
437#else
438	return (-1);
439#endif
440}
441
442/*
443 * Set the security level of the kernel.
444 */
445void
446setsecuritylevel(int newlevel)
447{
448#ifdef KERN_SECURELVL
449	int name[2], curlevel;
450
451	curlevel = getsecuritylevel();
452	if (newlevel == curlevel)
453		return;
454	name[0] = CTL_KERN;
455	name[1] = KERN_SECURELVL;
456	if (sysctl(name, 2, NULL, NULL, &newlevel, sizeof newlevel) == -1) {
457		emergency(
458		    "cannot change kernel security level from %d to %d: %s",
459		    curlevel, newlevel, strerror(errno));
460		return;
461	}
462#ifdef SECURE
463	warning("kernel security level changed from %d to %d",
464	    curlevel, newlevel);
465#endif
466#endif
467}
468
469/*
470 * Change states in the finite state machine.
471 * The initial state is passed as an argument.
472 */
473void
474transition(state_t s)
475{
476	for (;;)
477		s = (*state_funcs[s])();
478}
479
480/*
481 * Close out the accounting files for a login session.
482 * NB: should send a message to the session logger to avoid blocking.
483 */
484void
485clear_session_logs(session_t *sp)
486{
487	char *line = sp->se_device + sizeof(_PATH_DEV) - 1;
488
489	if (logout(line))
490		logwtmp(line, "", "");
491}
492
493/*
494 * Start a session and allocate a controlling terminal.
495 * Only called by children of init after forking.
496 */
497void
498setctty(char *name)
499{
500	int fd;
501
502	(void) revoke(name);
503	sleep(2);			/* leave DTR low */
504	if ((fd = open(name, O_RDWR)) == -1) {
505		stall("can't open %s: %m", name);
506		_exit(1);
507	}
508	if (login_tty(fd) == -1) {
509		stall("can't get %s for controlling terminal: %m", name);
510		_exit(1);
511	}
512}
513
514/*
515 * Bring the system up single user.
516 */
517state_t
518f_single_user(void)
519{
520	pid_t pid, wpid;
521	int status;
522	sigset_t mask;
523	char shell[PATH_MAX];		/* Allocate space here */
524	char name[PATH_MAX];		/* Name (argv[0]) of shell */
525	char *argv[2];
526#ifdef SECURE
527	struct ttyent *typ;
528	struct passwd *pp;
529	static const char banner[] =
530		"Enter root password, or ^D to go multi-user\n";
531	char *clear;
532	char pbuf[1024];
533#endif
534
535	/* Init shell and name */
536	strlcpy(shell, _PATH_BSHELL, sizeof shell);
537	strlcpy(name, "-sh", sizeof name);
538
539	/*
540	 * If the kernel is in secure mode, downgrade it to insecure mode.
541	 */
542	if (getsecuritylevel() > 0)
543		setsecuritylevel(0);
544
545	if ((pid = fork()) == 0) {
546		/*
547		 * Start the single user session.
548		 */
549		setctty(_PATH_CONSOLE);
550
551#ifdef SECURE
552		/*
553		 * Check the root password.
554		 * We don't care if the console is 'on' by default;
555		 * it's the only tty that can be 'off' and 'secure'.
556		 */
557		typ = getttynam("console");
558		pp = getpwnam_shadow("root");
559		if (typ && (typ->ty_status & TTY_SECURE) == 0 && pp &&
560		    *pp->pw_passwd) {
561			write(STDERR_FILENO, banner, sizeof banner - 1);
562			for (;;) {
563				int ok = 0;
564				clear = readpassphrase("Password:", pbuf,
565				    sizeof(pbuf), RPP_ECHO_OFF);
566				if (clear == NULL || *clear == '\0')
567					_exit(0);
568				if (crypt_checkpass(clear, pp->pw_passwd) == 0)
569					ok = 1;
570				explicit_bzero(pbuf, sizeof(pbuf));
571				if (ok)
572					break;
573				warning("single-user login failed\n");
574			}
575		}
576		endttyent();
577		endpwent();
578#endif /* SECURE */
579
580#ifdef DEBUGSHELL
581		{
582			char altshell[128], *cp = altshell;
583			int num;
584
585#define	SHREQUEST \
586	"Enter pathname of shell or RETURN for sh: "
587
588			(void)write(STDERR_FILENO,
589			    SHREQUEST, sizeof(SHREQUEST) - 1);
590			while ((num = read(STDIN_FILENO, cp, 1)) != -1 &&
591			    num != 0 && *cp != '\n' && cp < &altshell[127])
592				cp++;
593			*cp = '\0';
594
595			/* Copy in alternate shell */
596			if (altshell[0] != '\0'){
597				char *p;
598
599				/* Binary to exec */
600				strlcpy(shell, altshell, sizeof shell);
601
602				/* argv[0] */
603				p = strrchr(altshell, '/');
604				if(p == NULL) p = altshell;
605				else p++;
606
607				name[0] = '-';
608				strlcpy(&name[1], p, sizeof name -1);
609			}
610		}
611#endif /* DEBUGSHELL */
612
613		/*
614		 * Unblock signals.
615		 * We catch all the interesting ones,
616		 * and those are reset to SIG_DFL on exec.
617		 */
618		sigemptyset(&mask);
619		sigprocmask(SIG_SETMASK, &mask, NULL);
620
621		/*
622		 * Fire off a shell.
623		 * If the default one doesn't work, try the Bourne shell.
624		 */
625		argv[0] = name;
626		argv[1] = NULL;
627		setenv("PATH", _PATH_STDPATH, 1);
628		execv(shell, argv);
629		emergency("can't exec %s for single user: %m", shell);
630
631		argv[0] = "-sh";
632		argv[1] = NULL;
633		execv(_PATH_BSHELL, argv);
634		emergency("can't exec %s for single user: %m", _PATH_BSHELL);
635		sleep(STALL_TIMEOUT);
636		_exit(1);
637	}
638
639	if (pid == -1) {
640		/*
641		 * We are seriously hosed.  Do our best.
642		 */
643		emergency("can't fork single-user shell, trying again");
644		while (waitpid(-1, NULL, WNOHANG) > 0)
645			continue;
646		return single_user;
647	}
648
649	requested_transition = 0;
650	do {
651		if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1)
652			collect_child(wpid);
653		if (wpid == -1) {
654			if (errno == EINTR)
655				continue;
656			warning("wait for single-user shell failed: %m; restarting");
657			return single_user;
658		}
659		if (wpid == pid && WIFSTOPPED(status)) {
660			warning("init: shell stopped, restarting\n");
661			kill(pid, SIGCONT);
662			wpid = -1;
663		}
664	} while (wpid != pid && !requested_transition);
665
666	if (requested_transition)
667		return requested_transition;
668
669	if (!WIFEXITED(status)) {
670		if (WTERMSIG(status) == SIGKILL) {
671			/*
672			 *  reboot(8) killed shell?
673			 */
674			warning("single user shell terminated.");
675			sleep(STALL_TIMEOUT);
676			_exit(0);
677		} else {
678			warning("single user shell terminated, restarting");
679			return single_user;
680		}
681	}
682
683	runcom_mode = FASTBOOT;
684	return runcom;
685}
686
687/*
688 * Run the system startup script.
689 */
690state_t
691f_runcom(void)
692{
693	pid_t pid, wpid;
694	int status;
695	char *argv[4];
696	struct sigaction sa;
697
698	if ((pid = fork()) == 0) {
699		memset(&sa, 0, sizeof sa);
700		sigemptyset(&sa.sa_mask);
701		sa.sa_flags = 0;
702		sa.sa_handler = SIG_IGN;
703		(void) sigaction(SIGTSTP, &sa, NULL);
704		(void) sigaction(SIGHUP, &sa, NULL);
705
706		setctty(_PATH_CONSOLE);
707
708		argv[0] = "sh";
709		argv[1] = _PATH_RUNCOM;
710		argv[2] = runcom_mode == AUTOBOOT ? "autoboot" : NULL;
711		argv[3] = NULL;
712
713		sigprocmask(SIG_SETMASK, &sa.sa_mask, NULL);
714
715		setprocresources(RESOURCE_RC);
716
717		execv(_PATH_BSHELL, argv);
718		stall("can't exec %s for %s: %m", _PATH_BSHELL, _PATH_RUNCOM);
719		_exit(1);	/* force single user mode */
720	}
721
722	if (pid == -1) {
723		emergency("can't fork for %s on %s: %m",
724			_PATH_BSHELL, _PATH_RUNCOM);
725		while (waitpid(-1, NULL, WNOHANG) > 0)
726			continue;
727		sleep(STALL_TIMEOUT);
728		return single_user;
729	}
730
731	/*
732	 * Copied from single_user().  This is a bit paranoid.
733	 */
734	do {
735		if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1)
736			collect_child(wpid);
737		if (wpid == -1) {
738			if (errno == EINTR)
739				continue;
740			warning("wait for %s on %s failed: %m; going to single user mode",
741			    _PATH_BSHELL, _PATH_RUNCOM);
742			return single_user;
743		}
744		if (wpid == pid && WIFSTOPPED(status)) {
745			warning("init: %s on %s stopped, restarting\n",
746			    _PATH_BSHELL, _PATH_RUNCOM);
747			kill(pid, SIGCONT);
748			wpid = -1;
749		}
750	} while (wpid != pid);
751
752	if (WIFSIGNALED(status) && WTERMSIG(status) == SIGTERM &&
753	    requested_transition == catatonia) {
754		/* /etc/rc executed /sbin/reboot; wait for the end quietly */
755		sigset_t s;
756
757		sigfillset(&s);
758		for (;;)
759			sigsuspend(&s);
760	}
761
762	if (!WIFEXITED(status)) {
763		warning("%s on %s terminated abnormally, going to single user mode",
764		    _PATH_BSHELL, _PATH_RUNCOM);
765		return single_user;
766	}
767
768	if (WEXITSTATUS(status))
769		return single_user;
770
771	runcom_mode = AUTOBOOT;		/* the default */
772	/* NB: should send a message to the session logger to avoid blocking. */
773	logwtmp("~", "reboot", "");
774	return read_ttys;
775}
776
777/*
778 * Compare session keys.
779 */
780static int
781cmp_sessions(session_t *sp1, session_t *sp2)
782{
783	if (sp1->se_process < sp2->se_process)
784		return (-1);
785	if (sp1->se_process > sp2->se_process)
786		return (1);
787	return (0);
788}
789
790/*
791 * Add a new login session.
792 */
793void
794add_session(session_t *sp)
795{
796	if (RB_INSERT(session_tree, &session_tree, sp) != NULL)
797		emergency("insert %d: %s", sp->se_process, strerror(errno));
798}
799
800/*
801 * Delete an old login session.
802 */
803void
804del_session(session_t *sp)
805{
806	RB_REMOVE(session_tree, &session_tree, sp);
807}
808
809/*
810 * Look up a login session by pid.
811 */
812session_t *
813find_session(pid_t pid)
814{
815	struct init_session s;
816
817	s.se_process = pid;
818	return (RB_FIND(session_tree, &session_tree, &s));
819}
820
821/*
822 * Construct an argument vector from a command line.
823 */
824char **
825construct_argv(char *command)
826{
827	int argc = 0;
828	char **argv = calloc((strlen(command) + 1) / 2 + 1, sizeof (char *));
829	static const char separators[] = " \t";
830
831	if (argv == NULL)
832		return (0);
833
834	if ((argv[argc++] = strtok(command, separators)) == 0) {
835		free(argv);
836		return (0);
837	}
838	while ((argv[argc++] = strtok(NULL, separators)))
839		continue;
840	return (argv);
841}
842
843/*
844 * Deallocate a session descriptor.
845 */
846void
847free_session(session_t *sp)
848{
849	free(sp->se_device);
850	if (sp->se_getty) {
851		free(sp->se_getty);
852		free(sp->se_getty_argv);
853	}
854	if (sp->se_window) {
855		free(sp->se_window);
856		free(sp->se_window_argv);
857	}
858	free(sp);
859}
860
861/*
862 * Allocate a new session descriptor.
863 */
864session_t *
865new_session(session_t *sprev, int session_index, struct ttyent *typ)
866{
867	session_t *sp;
868
869	if ((typ->ty_status & TTY_ON) == 0 ||
870	    typ->ty_name == 0 ||
871	    typ->ty_getty == 0)
872		return (0);
873
874	sp = calloc(1, sizeof (session_t));
875	if (sp == NULL)
876		err(1, "calloc");
877
878	sp->se_flags = SE_PRESENT;
879	sp->se_index = session_index;
880
881	if (asprintf(&sp->se_device, "%s%s", _PATH_DEV, typ->ty_name) == -1)
882		err(1, "asprintf");
883
884	if (setupargv(sp, typ) == 0) {
885		free_session(sp);
886		return (0);
887	}
888
889	sp->se_next = NULL;
890	if (sprev == NULL) {
891		sessions = sp;
892		sp->se_prev = NULL;
893	} else {
894		sprev->se_next = sp;
895		sp->se_prev = sprev;
896	}
897
898	return (sp);
899}
900
901/*
902 * Calculate getty and if useful window argv vectors.
903 */
904int
905setupargv(session_t *sp, struct ttyent *typ)
906{
907	if (sp->se_getty) {
908		free(sp->se_getty);
909		free(sp->se_getty_argv);
910	}
911	if (asprintf(&sp->se_getty, "%s %s", typ->ty_getty, typ->ty_name) == -1)
912		err(1, "asprintf");
913	sp->se_getty_argv = construct_argv(sp->se_getty);
914	if (sp->se_getty_argv == 0) {
915		warning("can't parse getty for port %s", sp->se_device);
916		free(sp->se_getty);
917		sp->se_getty = NULL;
918		return (0);
919	}
920	if (typ->ty_window) {
921		free(sp->se_window);
922		sp->se_window = strdup(typ->ty_window);
923		if (sp->se_window == NULL) {
924			warning("can't allocate window");
925			return (0);
926		}
927		sp->se_window_argv = construct_argv(sp->se_window);
928		if (sp->se_window_argv == NULL) {
929			warning("can't parse window for port %s",
930			    sp->se_device);
931			free(sp->se_window);
932			sp->se_window = NULL;
933			return (0);
934		}
935	}
936	return (1);
937}
938
939/*
940 * Walk the list of ttys and create sessions for each active line.
941 */
942state_t
943f_read_ttys(void)
944{
945	int session_index = 0;
946	session_t *sp, *snext;
947	struct ttyent *typ;
948
949	/*
950	 * Destroy any previous session state.
951	 * There shouldn't be any, but just in case...
952	 */
953	for (sp = sessions; sp; sp = snext) {
954		if (sp->se_process)
955			clear_session_logs(sp);
956		snext = sp->se_next;
957		free_session(sp);
958	}
959	sessions = NULL;
960
961	/*
962	 * Allocate a session entry for each active port.
963	 * Note that sp starts at 0.
964	 */
965	while ((typ = getttyent()))
966		if ((snext = new_session(sp, ++session_index, typ)))
967			sp = snext;
968
969	endttyent();
970
971	return multi_user;
972}
973
974/*
975 * Start a window system running.
976 */
977void
978start_window_system(session_t *sp)
979{
980	pid_t pid;
981	sigset_t mask;
982
983	if ((pid = fork()) == -1) {
984		emergency("can't fork for window system on port %s: %m",
985		    sp->se_device);
986		/* hope that getty fails and we can try again */
987		return;
988	}
989
990	if (pid)
991		return;
992
993	sigemptyset(&mask);
994	sigprocmask(SIG_SETMASK, &mask, NULL);
995
996	if (setsid() < 0)
997		emergency("setsid failed (window) %m");
998
999	setprocresources(RESOURCE_WINDOW);
1000
1001	execv(sp->se_window_argv[0], sp->se_window_argv);
1002	stall("can't exec window system '%s' for port %s: %m",
1003	    sp->se_window_argv[0], sp->se_device);
1004	_exit(1);
1005}
1006
1007/*
1008 * Start a login session running.
1009 * For first open, man-handle tty directly to determine if it
1010 * really exists. It is not efficient to spawn gettys on devices
1011 * that do not exist.
1012 */
1013pid_t
1014start_getty(session_t *sp)
1015{
1016	pid_t pid;
1017	sigset_t mask;
1018	time_t current_time = time(NULL);
1019	int p[2], new = 1;
1020
1021	if (sp->se_flags & SE_DEVEXISTS)
1022		new = 0;
1023
1024	if (new) {
1025		if (pipe(p) == -1)
1026			return (-1);
1027	}
1028
1029	/*
1030	 * fork(), not vfork() -- we can't afford to block.
1031	 */
1032	if ((pid = fork()) == -1) {
1033		emergency("can't fork for getty on port %s: %m", sp->se_device);
1034		return (-1);
1035	}
1036
1037	if (pid) {
1038		if (new) {
1039			char c;
1040
1041			close(p[1]);
1042			if (read(p[0], &c, 1) != 1) {
1043				close(p[0]);
1044				return (-1);
1045			}
1046			close(p[0]);
1047			if (c == '1')
1048				sp->se_flags |= SE_DEVEXISTS;
1049			else
1050				sp->se_flags |= SE_SHUTDOWN;
1051		}
1052		return (pid);
1053	}
1054	if (new) {
1055		int fd;
1056
1057		close(p[0]);
1058		fd = open(sp->se_device, O_RDONLY | O_NONBLOCK, 0666);
1059		if (fd == -1 && (errno == ENXIO || errno == ENOENT ||
1060		    errno == EISDIR)) {
1061			(void)write(p[1], "0", 1);
1062			close(p[1]);
1063			_exit(1);
1064		}
1065		(void)write(p[1], "1", 1);
1066		close(p[1]);
1067		close(fd);
1068		sleep(1);
1069	}
1070
1071	if (current_time > sp->se_started &&
1072	    current_time - sp->se_started < GETTY_SPACING) {
1073		warning("getty repeating too quickly on port %s, sleeping",
1074		    sp->se_device);
1075		sleep(GETTY_SLEEP);
1076	}
1077
1078	if (sp->se_window) {
1079		start_window_system(sp);
1080		sleep(WINDOW_WAIT);
1081	}
1082
1083	sigemptyset(&mask);
1084	sigprocmask(SIG_SETMASK, &mask, NULL);
1085
1086	setprocresources(RESOURCE_GETTY);
1087
1088	execv(sp->se_getty_argv[0], sp->se_getty_argv);
1089	stall("can't exec getty '%s' for port %s: %m",
1090	    sp->se_getty_argv[0], sp->se_device);
1091	_exit(1);
1092}
1093
1094/*
1095 * Collect exit status for a child.
1096 * If an exiting login, start a new login running.
1097 */
1098void
1099collect_child(pid_t pid)
1100{
1101	session_t *sp, *sprev, *snext;
1102
1103	if (sessions == NULL)
1104		return;
1105
1106	if ((sp = find_session(pid)) == NULL)
1107		return;
1108
1109	clear_session_logs(sp);
1110	login_fbtab(sp->se_device + sizeof(_PATH_DEV) - 1, 0, 0);
1111	del_session(sp);
1112	sp->se_process = 0;
1113
1114	if (sp->se_flags & SE_SHUTDOWN) {
1115		if ((sprev = sp->se_prev))
1116			sprev->se_next = sp->se_next;
1117		else
1118			sessions = sp->se_next;
1119		if ((snext = sp->se_next))
1120			snext->se_prev = sp->se_prev;
1121		free_session(sp);
1122		return;
1123	}
1124
1125	if ((pid = start_getty(sp)) == -1) {
1126		/* serious trouble */
1127		requested_transition = clean_ttys;
1128		return;
1129	}
1130
1131	sp->se_process = pid;
1132	sp->se_started = time(NULL);
1133	add_session(sp);
1134}
1135
1136/*
1137 * Catch a signal and request a state transition.
1138 */
1139void
1140transition_handler(int sig)
1141{
1142
1143	switch (sig) {
1144	case SIGHUP:
1145		requested_transition = clean_ttys;
1146		break;
1147	case SIGINT:
1148		requested_transition = do_reboot;
1149		break;
1150	case SIGTERM:
1151		requested_transition = death;
1152		break;
1153	case SIGUSR1:
1154		requested_transition = nice_death;
1155		break;
1156	case SIGUSR2:
1157		requested_transition = hard_death;
1158		break;
1159	case SIGTSTP:
1160		requested_transition = catatonia;
1161		break;
1162	default:
1163		requested_transition = 0;
1164		break;
1165	}
1166}
1167
1168/*
1169 * Take the system multiuser.
1170 */
1171state_t
1172f_multi_user(void)
1173{
1174	pid_t pid;
1175	session_t *sp;
1176
1177	/*
1178	 * If the administrator has not set the security level to -1
1179	 * to indicate that the kernel should not run multiuser in secure
1180	 * mode, and the run script has not set a higher level of security
1181	 * than level 1, then put the kernel into secure mode.
1182	 */
1183	if (requested_transition != catatonia) {
1184		if (getsecuritylevel() == 0)
1185			setsecuritylevel(1);
1186	}
1187
1188	requested_transition = 0;
1189
1190	for (sp = sessions; sp; sp = sp->se_next) {
1191		if (sp->se_process)
1192			continue;
1193		if ((pid = start_getty(sp)) == -1) {
1194			/* serious trouble */
1195			requested_transition = clean_ttys;
1196			break;
1197		}
1198		sp->se_process = pid;
1199		sp->se_started = time(NULL);
1200		add_session(sp);
1201	}
1202
1203	while (!requested_transition)
1204		if ((pid = waitpid(-1, NULL, 0)) != -1)
1205			collect_child(pid);
1206
1207	return requested_transition;
1208}
1209
1210/*
1211 * This is an n-squared algorithm.  We hope it isn't run often...
1212 */
1213state_t
1214f_clean_ttys(void)
1215{
1216	session_t *sp, *sprev;
1217	struct ttyent *typ;
1218	int session_index = 0;
1219	int devlen;
1220
1221	for (sp = sessions; sp; sp = sp->se_next)
1222		sp->se_flags &= ~SE_PRESENT;
1223
1224	devlen = sizeof(_PATH_DEV) - 1;
1225	while ((typ = getttyent())) {
1226		++session_index;
1227
1228		for (sprev = NULL, sp = sessions; sp; sprev = sp, sp = sp->se_next)
1229			if (strcmp(typ->ty_name, sp->se_device + devlen) == 0)
1230				break;
1231
1232		if (sp) {
1233			sp->se_flags |= SE_PRESENT;
1234			if (sp->se_index != session_index) {
1235				warning("port %s changed utmp index from %d to %d",
1236				    sp->se_device, sp->se_index,
1237				    session_index);
1238				sp->se_index = session_index;
1239			}
1240			if ((typ->ty_status & TTY_ON) == 0 ||
1241			    typ->ty_getty == 0) {
1242				sp->se_flags |= SE_SHUTDOWN;
1243				kill(sp->se_process, SIGHUP);
1244				continue;
1245			}
1246			sp->se_flags &= ~SE_SHUTDOWN;
1247			if (setupargv(sp, typ) == 0) {
1248				warning("can't parse getty for port %s",
1249				    sp->se_device);
1250				sp->se_flags |= SE_SHUTDOWN;
1251				kill(sp->se_process, SIGHUP);
1252			}
1253			continue;
1254		}
1255
1256		new_session(sprev, session_index, typ);
1257	}
1258
1259	endttyent();
1260
1261	for (sp = sessions; sp; sp = sp->se_next)
1262		if ((sp->se_flags & SE_PRESENT) == 0) {
1263			sp->se_flags |= SE_SHUTDOWN;
1264			kill(sp->se_process, SIGHUP);
1265		}
1266
1267	return multi_user;
1268}
1269
1270/*
1271 * Block further logins.
1272 */
1273state_t
1274f_catatonia(void)
1275{
1276	session_t *sp;
1277
1278	for (sp = sessions; sp; sp = sp->se_next)
1279		sp->se_flags |= SE_SHUTDOWN;
1280
1281	return multi_user;
1282}
1283
1284/*
1285 * Note SIGALRM.
1286 */
1287void
1288alrm_handler(int sig)
1289{
1290	clang = 1;
1291}
1292
1293int death_howto = RB_HALT;
1294
1295/*
1296 * Reboot the system.
1297 */
1298state_t
1299f_do_reboot(void)
1300{
1301	death_howto = RB_AUTOBOOT;
1302	return nice_death;
1303}
1304
1305/*
1306 * Bring the system down nicely, then we must powerdown because something
1307 * is very wrong.
1308 */
1309state_t
1310f_hard_death(void)
1311{
1312	death_howto |= RB_POWERDOWN;
1313	return nice_death;
1314}
1315
1316/*
1317 * Bring the system down to single user nicely, after run the shutdown script.
1318 */
1319state_t
1320f_nice_death(void)
1321{
1322	session_t *sp;
1323	int i;
1324	pid_t pid;
1325	static const int death_sigs[3] = { SIGHUP, SIGTERM, SIGKILL };
1326	int status;
1327
1328#ifdef CPU_LIDSUSPEND
1329	int mib[] = {CTL_MACHDEP, CPU_LIDACTION};
1330	int lidaction = 0;
1331
1332	if ((death_howto & RB_POWERDOWN) &&
1333	    (sysctl(mib, 2, NULL, NULL, &lidaction,
1334		    sizeof(lidaction)) == -1) && (errno != EOPNOTSUPP))
1335			warning("cannot disable lid action");
1336#endif
1337
1338	for (sp = sessions; sp; sp = sp->se_next) {
1339		sp->se_flags &= ~SE_PRESENT;
1340		sp->se_flags |= SE_SHUTDOWN;
1341		kill(sp->se_process, SIGHUP);
1342	}
1343
1344	/* terminate the accounting process */
1345	acct(NULL);
1346
1347	/* NB: should send a message to the session logger to avoid blocking. */
1348	logwtmp("~", "shutdown", "");
1349
1350	if (access(_PATH_RUNCOM, R_OK) != -1) {
1351		struct sigaction sa;
1352
1353		switch ((pid = fork())) {
1354		case -1:
1355			break;
1356		case 0:
1357
1358			memset(&sa, 0, sizeof sa);
1359			sigemptyset(&sa.sa_mask);
1360			sa.sa_flags = 0;
1361			sa.sa_handler = SIG_IGN;
1362			(void) sigaction(SIGTSTP, &sa, NULL);
1363			(void) sigaction(SIGHUP, &sa, NULL);
1364
1365			setctty(_PATH_CONSOLE);
1366
1367			sigprocmask(SIG_SETMASK, &sa.sa_mask, NULL);
1368
1369			execl(_PATH_BSHELL, "sh", _PATH_RUNCOM, "shutdown",
1370			    (char *)NULL);
1371			stall("can't exec %s for %s %s: %m", _PATH_BSHELL,
1372			    _PATH_RUNCOM, "shutdown");
1373			_exit(1);
1374		default:
1375			waitpid(pid, &status, 0);
1376			if (WIFEXITED(status) && WEXITSTATUS(status) == 2)
1377				death_howto |= RB_POWERDOWN;
1378		}
1379	}
1380
1381	for (i = 0; i < 3; ++i) {
1382		if (kill(-1, death_sigs[i]) == -1 && errno == ESRCH)
1383			goto die;
1384
1385		clang = 0;
1386		alarm(DEATH_WATCH);
1387		do {
1388			if ((pid = waitpid(-1, NULL, 0)) != -1)
1389				collect_child(pid);
1390		} while (clang == 0 && errno != ECHILD);
1391
1392		if (errno == ECHILD)
1393			goto die;
1394	}
1395
1396	warning("some processes would not die; ps axl advised");
1397
1398die:
1399	reboot(death_howto);
1400
1401	/* ... and if that fails.. oh well */
1402	return single_user;
1403}
1404
1405/*
1406 * Bring the system down to single user.
1407 */
1408state_t
1409f_death(void)
1410{
1411	session_t *sp;
1412	int i;
1413	pid_t pid;
1414	static const int death_sigs[3] = { SIGHUP, SIGTERM, SIGKILL };
1415
1416	/* terminate the accounting process */
1417	acct(NULL);
1418
1419	for (sp = sessions; sp; sp = sp->se_next)
1420		sp->se_flags |= SE_SHUTDOWN;
1421
1422	/* NB: should send a message to the session logger to avoid blocking. */
1423	logwtmp("~", "shutdown", "");
1424
1425	for (i = 0; i < 3; ++i) {
1426		if (kill(-1, death_sigs[i]) == -1 && errno == ESRCH)
1427			return single_user;
1428
1429		clang = 0;
1430		alarm(DEATH_WATCH);
1431		do {
1432			if ((pid = waitpid(-1, NULL, 0)) != -1)
1433				collect_child(pid);
1434		} while (clang == 0 && errno != ECHILD);
1435
1436		if (errno == ECHILD)
1437			return single_user;
1438	}
1439
1440	warning("some processes would not die; ps axl advised");
1441
1442	return single_user;
1443}
1444
1445#ifdef LOGIN_CAP
1446void
1447setprocresources(char *class)
1448{
1449	login_cap_t *lc;
1450
1451	if ((lc = login_getclass(class)) != NULL) {
1452		setusercontext(lc, NULL, 0,
1453		    LOGIN_SETPRIORITY|LOGIN_SETRESOURCES|LOGIN_SETUMASK);
1454		login_close(lc);
1455	}
1456}
1457#endif
1458