init.c revision 1.69 
1/*	$OpenBSD: init.c,v 1.69 2019/06/28 13:32:44 deraadt Exp $	*/
2/*	$NetBSD: init.c,v 1.22 1996/05/15 23:29:33 jtc Exp $	*/
3
4/*-
5 * Copyright (c) 1991, 1993
6 *	The Regents of the University of California.  All rights reserved.
7 *
8 * This code is derived from software contributed to Berkeley by
9 * Donn Seeley at Berkeley Software Design, Inc.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 *    notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 *    notice, this list of conditions and the following disclaimer in the
18 *    documentation and/or other materials provided with the distribution.
19 * 3. 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 <login_cap.h>
49#include <signal.h>
50#include <stdarg.h>
51#include <stdio.h>
52#include <stdlib.h>
53#include <string.h>
54#include <syslog.h>
55#include <time.h>
56#include <ttyent.h>
57#include <unistd.h>
58#include <util.h>
59
60#ifdef SECURE
61#include <pwd.h>
62#include <readpassphrase.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);
94
95typedef enum {
96	invalid_state,
97	single_user,
98	runcom,
99	read_ttys,
100	multi_user,
101	clean_ttys,
102	catatonia,
103	death,
104	do_reboot,
105	hard_death,
106	nice_death
107} state_t;
108typedef state_t (*state_func_t)(void);
109
110state_t f_single_user(void);
111state_t f_runcom(void);
112state_t f_read_ttys(void);
113state_t f_multi_user(void);
114state_t f_clean_ttys(void);
115state_t f_catatonia(void);
116state_t f_death(void);
117state_t f_do_reboot(void);
118state_t f_hard_death(void);
119state_t f_nice_death(void);
120
121state_func_t state_funcs[] = {
122	NULL,
123	f_single_user,
124	f_runcom,
125	f_read_ttys,
126	f_multi_user,
127	f_clean_ttys,
128	f_catatonia,
129	f_death,
130	f_do_reboot,
131	f_hard_death,
132	f_nice_death
133};
134
135enum { AUTOBOOT, FASTBOOT } runcom_mode = AUTOBOOT;
136
137void transition(state_t);
138volatile sig_atomic_t requested_transition = DEFAULT_STATE;
139
140void setctty(char *);
141
142typedef struct init_session {
143	int	se_index;		/* index of entry in ttys file */
144	pid_t	se_process;		/* controlling process */
145	struct	timespec se_started;	/* used to avoid thrashing */
146	int	se_flags;		/* status of session */
147#define	SE_SHUTDOWN	0x1		/* session won't be restarted */
148#define	SE_PRESENT	0x2		/* session is in /etc/ttys */
149#define	SE_DEVEXISTS	0x4		/* open does not result in ENODEV */
150	char	*se_device;		/* filename of port */
151	char	*se_getty;		/* what to run on that port */
152	char	**se_getty_argv;	/* pre-parsed argument array */
153	char	*se_window;		/* window system (started only once) */
154	char	**se_window_argv;	/* pre-parsed argument array */
155	struct	init_session *se_prev;
156	struct	init_session *se_next;
157	RB_ENTRY(init_session) se_entry;
158} session_t;
159
160static int cmp_sessions(session_t *, session_t *);
161RB_HEAD(session_tree, init_session) session_tree = RB_INITIALIZER(session_tree);
162RB_PROTOTYPE(session_tree, init_session, se_entry, cmp_sessions);
163RB_GENERATE(session_tree, init_session, se_entry, cmp_sessions);
164
165void free_session(session_t *);
166session_t *new_session(session_t *, int, struct ttyent *);
167session_t *sessions;
168
169char **construct_argv(char *);
170void start_window_system(session_t *);
171void collect_child(pid_t);
172pid_t start_getty(session_t *);
173void transition_handler(int);
174void alrm_handler(int);
175void setsecuritylevel(int);
176void setprocresources(char *);
177int getsecuritylevel(void);
178int setupargv(session_t *, struct ttyent *);
179int clang;
180
181void clear_session_logs(session_t *);
182
183void add_session(session_t *);
184void del_session(session_t *);
185session_t *find_session(pid_t);
186
187/*
188 * The mother of all processes.
189 */
190int
191main(int argc, char *argv[])
192{
193	int c, fd;
194	struct sigaction sa;
195	sigset_t mask;
196
197	/* Dispose of random users. */
198	if (getuid() != 0) {
199		(void)fprintf(stderr, "init: %s\n", strerror(EPERM));
200		exit (1);
201	}
202
203	/* System V users like to reexec init. */
204	if (getpid() != 1) {
205		(void)fprintf(stderr, "init: already running\n");
206		exit (1);
207	}
208
209	/*
210	 * Paranoia.
211	 */
212	if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
213		(void)dup2(fd, STDIN_FILENO);
214		(void)dup2(fd, STDOUT_FILENO);
215		(void)dup2(fd, STDERR_FILENO);
216		if (fd > 2)
217			(void)close(fd);
218	}
219
220	/*
221	 * Note that this does NOT open a file...
222	 * Does 'init' deserve its own facility number?
223	 */
224	openlog("init", LOG_CONS|LOG_ODELAY, LOG_AUTH);
225
226	/*
227	 * Create an initial session.
228	 */
229	if (setsid() == -1)
230		warning("initial setsid() failed: %m");
231
232	/*
233	 * Establish an initial user so that programs running
234	 * single user do not freak out and die (like passwd).
235	 */
236	if (setlogin("root") == -1)
237		warning("setlogin() failed: %m");
238
239	/*
240	 * This code assumes that we always get arguments through flags,
241	 * never through bits set in some random machine register.
242	 */
243	while ((c = getopt(argc, argv, "sf")) != -1)
244		switch (c) {
245		case 's':
246			requested_transition = single_user;
247			break;
248		case 'f':
249			runcom_mode = FASTBOOT;
250			break;
251		default:
252			warning("unrecognized flag '-%c'", c);
253			break;
254		}
255
256	if (optind != argc)
257		warning("ignoring excess arguments");
258
259	/*
260	 * We catch or block signals rather than ignore them,
261	 * so that they get reset on exec.
262	 */
263	handle(disaster, SIGABRT, SIGFPE, SIGILL, SIGSEGV,
264	    SIGBUS, SIGSYS, SIGXCPU, SIGXFSZ, 0);
265	handle(transition_handler, SIGHUP, SIGINT, SIGTERM, SIGTSTP,
266            SIGUSR1, SIGUSR2, 0);
267	handle(alrm_handler, SIGALRM, 0);
268	sigfillset(&mask);
269	delset(&mask, SIGABRT, SIGFPE, SIGILL, SIGSEGV, SIGBUS, SIGSYS,
270	    SIGXCPU, SIGXFSZ, SIGHUP, SIGINT, SIGTERM, SIGUSR1, SIGUSR2,
271	    SIGTSTP, SIGALRM, 0);
272	sigprocmask(SIG_SETMASK, &mask, NULL);
273	memset(&sa, 0, sizeof sa);
274	sigemptyset(&sa.sa_mask);
275	sa.sa_flags = 0;
276	sa.sa_handler = SIG_IGN;
277	(void) sigaction(SIGTTIN, &sa, NULL);
278	(void) sigaction(SIGTTOU, &sa, NULL);
279
280	/*
281	 * Start the state machine.
282	 */
283	transition(requested_transition);
284
285	/*
286	 * Should never reach here.
287	 */
288	exit(1);
289}
290
291/*
292 * Associate a function with a signal handler.
293 */
294void
295handle(sig_t handler, ...)
296{
297	int sig;
298	struct sigaction sa;
299	sigset_t mask_everything;
300	va_list ap;
301
302	va_start(ap, handler);
303
304	memset(&sa, 0, sizeof sa);
305	sa.sa_handler = handler;
306	sigfillset(&mask_everything);
307
308	while ((sig = va_arg(ap, int))) {
309		sa.sa_mask = mask_everything;
310		/* XXX SA_RESTART? */
311		sa.sa_flags = sig == SIGCHLD ? SA_NOCLDSTOP : 0;
312		sigaction(sig, &sa, NULL);
313	}
314	va_end(ap);
315}
316
317/*
318 * Delete a set of signals from a mask.
319 */
320void
321delset(sigset_t *maskp, ...)
322{
323	int sig;
324	va_list ap;
325
326	va_start(ap, maskp);
327	while ((sig = va_arg(ap, int)))
328		sigdelset(maskp, sig);
329	va_end(ap);
330}
331
332/*
333 * Log a message and sleep for a while (to give someone an opportunity
334 * to read it and to save log or hardcopy output if the problem is chronic).
335 * NB: should send a message to the session logger to avoid blocking.
336 */
337void
338stall(char *message, ...)
339{
340	va_list ap;
341
342	va_start(ap, message);
343	vsyslog(LOG_ALERT, message, ap);
344	va_end(ap);
345	closelog();
346	sleep(STALL_TIMEOUT);
347}
348
349/*
350 * Like stall(), but doesn't sleep.
351 * If cpp had variadic macros, the two functions could be #defines for another.
352 * NB: should send a message to the session logger to avoid blocking.
353 */
354void
355warning(char *message, ...)
356{
357	va_list ap;
358
359	va_start(ap, message);
360	vsyslog(LOG_ALERT, message, ap);
361	va_end(ap);
362	closelog();
363}
364
365/*
366 * Log an emergency message.
367 * NB: should send a message to the session logger to avoid blocking.
368 */
369void
370emergency(char *message, ...)
371{
372	struct syslog_data sdata = SYSLOG_DATA_INIT;
373	va_list ap;
374
375	va_start(ap, message);
376	vsyslog_r(LOG_EMERG, &sdata, message, ap);
377	va_end(ap);
378}
379
380/*
381 * Catch an unexpected signal.
382 */
383void
384disaster(int sig)
385{
386	emergency("fatal signal: %s", strsignal(sig));
387
388	sleep(STALL_TIMEOUT);
389	_exit(sig);		/* reboot */
390}
391
392/*
393 * Get the security level of the kernel.
394 */
395int
396getsecuritylevel(void)
397{
398#ifdef KERN_SECURELVL
399	int name[2], curlevel;
400	size_t len;
401
402	name[0] = CTL_KERN;
403	name[1] = KERN_SECURELVL;
404	len = sizeof curlevel;
405	if (sysctl(name, 2, &curlevel, &len, NULL, 0) == -1) {
406		emergency("cannot get kernel security level: %s",
407		    strerror(errno));
408		return (-1);
409	}
410	return (curlevel);
411#else
412	return (-1);
413#endif
414}
415
416/*
417 * Set the security level of the kernel.
418 */
419void
420setsecuritylevel(int newlevel)
421{
422#ifdef KERN_SECURELVL
423	int name[2], curlevel;
424
425	curlevel = getsecuritylevel();
426	if (newlevel == curlevel)
427		return;
428	name[0] = CTL_KERN;
429	name[1] = KERN_SECURELVL;
430	if (sysctl(name, 2, NULL, NULL, &newlevel, sizeof newlevel) == -1) {
431		emergency(
432		    "cannot change kernel security level from %d to %d: %s",
433		    curlevel, newlevel, strerror(errno));
434		return;
435	}
436#ifdef SECURE
437	warning("kernel security level changed from %d to %d",
438	    curlevel, newlevel);
439#endif
440#endif
441}
442
443/*
444 * Change states in the finite state machine.
445 * The initial state is passed as an argument.
446 */
447void
448transition(state_t s)
449{
450	for (;;)
451		s = (*state_funcs[s])();
452}
453
454/*
455 * Close out the accounting files for a login session.
456 * NB: should send a message to the session logger to avoid blocking.
457 */
458void
459clear_session_logs(session_t *sp)
460{
461	char *line = sp->se_device + sizeof(_PATH_DEV) - 1;
462
463	if (logout(line))
464		logwtmp(line, "", "");
465}
466
467/*
468 * Start a session and allocate a controlling terminal.
469 * Only called by children of init after forking.
470 */
471void
472setctty(char *name)
473{
474	int fd;
475
476	(void) revoke(name);
477	sleep(2);			/* leave DTR low */
478	if ((fd = open(name, O_RDWR)) == -1) {
479		stall("can't open %s: %m", name);
480		_exit(1);
481	}
482	if (login_tty(fd) == -1) {
483		stall("can't get %s for controlling terminal: %m", name);
484		_exit(1);
485	}
486}
487
488/*
489 * Bring the system up single user.
490 */
491state_t
492f_single_user(void)
493{
494	pid_t pid, wpid;
495	int status;
496	sigset_t mask;
497	char shell[PATH_MAX];		/* Allocate space here */
498	char name[PATH_MAX];		/* Name (argv[0]) of shell */
499	char *argv[2];
500#ifdef SECURE
501	struct ttyent *typ;
502	struct passwd *pp;
503	static const char banner[] =
504		"Enter root password, or ^D to go multi-user\n";
505	char *clear;
506	char pbuf[1024];
507#endif
508
509	/* Init shell and name */
510	strlcpy(shell, _PATH_BSHELL, sizeof shell);
511	strlcpy(name, "-sh", sizeof name);
512
513	/*
514	 * If the kernel is in secure mode, downgrade it to insecure mode.
515	 */
516	if (getsecuritylevel() > 0)
517		setsecuritylevel(0);
518
519	if ((pid = fork()) == 0) {
520		/*
521		 * Start the single user session.
522		 */
523		setctty(_PATH_CONSOLE);
524
525#ifdef SECURE
526		/*
527		 * Check the root password.
528		 * We don't care if the console is 'on' by default;
529		 * it's the only tty that can be 'off' and 'secure'.
530		 */
531		typ = getttynam("console");
532		pp = getpwnam_shadow("root");
533		if (typ && (typ->ty_status & TTY_SECURE) == 0 && pp &&
534		    *pp->pw_passwd) {
535			write(STDERR_FILENO, banner, sizeof banner - 1);
536			for (;;) {
537				int ok = 0;
538				clear = readpassphrase("Password:", pbuf,
539				    sizeof(pbuf), RPP_ECHO_OFF);
540				if (clear == NULL || *clear == '\0')
541					_exit(0);
542				if (crypt_checkpass(clear, pp->pw_passwd) == 0)
543					ok = 1;
544				explicit_bzero(pbuf, sizeof(pbuf));
545				if (ok)
546					break;
547				warning("single-user login failed\n");
548			}
549		}
550		endttyent();
551		endpwent();
552#endif /* SECURE */
553
554#ifdef DEBUGSHELL
555		{
556			char altshell[128], *cp = altshell;
557			int num;
558
559#define	SHREQUEST \
560	"Enter pathname of shell or RETURN for sh: "
561
562			(void)write(STDERR_FILENO,
563			    SHREQUEST, sizeof(SHREQUEST) - 1);
564			while ((num = read(STDIN_FILENO, cp, 1)) != -1 &&
565			    num != 0 && *cp != '\n' && cp < &altshell[127])
566				cp++;
567			*cp = '\0';
568
569			/* Copy in alternate shell */
570			if (altshell[0] != '\0'){
571				char *p;
572
573				/* Binary to exec */
574				strlcpy(shell, altshell, sizeof shell);
575
576				/* argv[0] */
577				p = strrchr(altshell, '/');
578				if(p == NULL) p = altshell;
579				else p++;
580
581				name[0] = '-';
582				strlcpy(&name[1], p, sizeof name -1);
583			}
584		}
585#endif /* DEBUGSHELL */
586
587		/*
588		 * Unblock signals.
589		 * We catch all the interesting ones,
590		 * and those are reset to SIG_DFL on exec.
591		 */
592		sigemptyset(&mask);
593		sigprocmask(SIG_SETMASK, &mask, NULL);
594
595		/*
596		 * Fire off a shell.
597		 * If the default one doesn't work, try the Bourne shell.
598		 */
599		argv[0] = name;
600		argv[1] = NULL;
601		setenv("PATH", _PATH_STDPATH, 1);
602		execv(shell, argv);
603		emergency("can't exec %s for single user: %m", shell);
604
605		argv[0] = "-sh";
606		argv[1] = NULL;
607		execv(_PATH_BSHELL, argv);
608		emergency("can't exec %s for single user: %m", _PATH_BSHELL);
609		sleep(STALL_TIMEOUT);
610		_exit(1);
611	}
612
613	if (pid == -1) {
614		/*
615		 * We are seriously hosed.  Do our best.
616		 */
617		emergency("can't fork single-user shell, trying again");
618		while (waitpid(-1, NULL, WNOHANG) > 0)
619			continue;
620		return single_user;
621	}
622
623	requested_transition = 0;
624	do {
625		if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1)
626			collect_child(wpid);
627		if (wpid == -1) {
628			if (errno == EINTR)
629				continue;
630			warning("wait for single-user shell failed: %m; restarting");
631			return single_user;
632		}
633		if (wpid == pid && WIFSTOPPED(status)) {
634			warning("init: shell stopped, restarting\n");
635			kill(pid, SIGCONT);
636			wpid = -1;
637		}
638	} while (wpid != pid && !requested_transition);
639
640	if (requested_transition)
641		return requested_transition;
642
643	if (!WIFEXITED(status)) {
644		if (WTERMSIG(status) == SIGKILL) {
645			/*
646			 *  reboot(8) killed shell?
647			 */
648			warning("single user shell terminated.");
649			sleep(STALL_TIMEOUT);
650			_exit(0);
651		} else {
652			warning("single user shell terminated, restarting");
653			return single_user;
654		}
655	}
656
657	runcom_mode = FASTBOOT;
658	return runcom;
659}
660
661/*
662 * Run the system startup script.
663 */
664state_t
665f_runcom(void)
666{
667	pid_t pid, wpid;
668	int status;
669	char *argv[4];
670	struct sigaction sa;
671
672	if ((pid = fork()) == 0) {
673		memset(&sa, 0, sizeof sa);
674		sigemptyset(&sa.sa_mask);
675		sa.sa_flags = 0;
676		sa.sa_handler = SIG_IGN;
677		(void) sigaction(SIGTSTP, &sa, NULL);
678		(void) sigaction(SIGHUP, &sa, NULL);
679
680		setctty(_PATH_CONSOLE);
681
682		argv[0] = "sh";
683		argv[1] = _PATH_RUNCOM;
684		argv[2] = runcom_mode == AUTOBOOT ? "autoboot" : NULL;
685		argv[3] = NULL;
686
687		sigprocmask(SIG_SETMASK, &sa.sa_mask, NULL);
688
689		setprocresources(RESOURCE_RC);
690
691		execv(_PATH_BSHELL, argv);
692		stall("can't exec %s for %s: %m", _PATH_BSHELL, _PATH_RUNCOM);
693		_exit(1);	/* force single user mode */
694	}
695
696	if (pid == -1) {
697		emergency("can't fork for %s on %s: %m",
698			_PATH_BSHELL, _PATH_RUNCOM);
699		while (waitpid(-1, NULL, WNOHANG) > 0)
700			continue;
701		sleep(STALL_TIMEOUT);
702		return single_user;
703	}
704
705	/*
706	 * Copied from single_user().  This is a bit paranoid.
707	 */
708	do {
709		if ((wpid = waitpid(-1, &status, WUNTRACED)) != -1)
710			collect_child(wpid);
711		if (wpid == -1) {
712			if (errno == EINTR)
713				continue;
714			warning("wait for %s on %s failed: %m; going to single user mode",
715			    _PATH_BSHELL, _PATH_RUNCOM);
716			return single_user;
717		}
718		if (wpid == pid && WIFSTOPPED(status)) {
719			warning("init: %s on %s stopped, restarting\n",
720			    _PATH_BSHELL, _PATH_RUNCOM);
721			kill(pid, SIGCONT);
722			wpid = -1;
723		}
724	} while (wpid != pid);
725
726	if (WIFSIGNALED(status) && WTERMSIG(status) == SIGTERM &&
727	    requested_transition == catatonia) {
728		/* /etc/rc executed /sbin/reboot; wait for the end quietly */
729		sigset_t s;
730
731		sigfillset(&s);
732		for (;;)
733			sigsuspend(&s);
734	}
735
736	if (!WIFEXITED(status)) {
737		warning("%s on %s terminated abnormally, going to single user mode",
738		    _PATH_BSHELL, _PATH_RUNCOM);
739		return single_user;
740	}
741
742	if (WEXITSTATUS(status))
743		return single_user;
744
745	runcom_mode = AUTOBOOT;		/* the default */
746	/* NB: should send a message to the session logger to avoid blocking. */
747	logwtmp("~", "reboot", "");
748	return read_ttys;
749}
750
751/*
752 * Compare session keys.
753 */
754static int
755cmp_sessions(session_t *sp1, session_t *sp2)
756{
757	if (sp1->se_process < sp2->se_process)
758		return (-1);
759	if (sp1->se_process > sp2->se_process)
760		return (1);
761	return (0);
762}
763
764/*
765 * Add a new login session.
766 */
767void
768add_session(session_t *sp)
769{
770	if (RB_INSERT(session_tree, &session_tree, sp) != NULL)
771		emergency("insert %d: %s", sp->se_process, strerror(errno));
772}
773
774/*
775 * Delete an old login session.
776 */
777void
778del_session(session_t *sp)
779{
780	RB_REMOVE(session_tree, &session_tree, sp);
781}
782
783/*
784 * Look up a login session by pid.
785 */
786session_t *
787find_session(pid_t pid)
788{
789	struct init_session s;
790
791	s.se_process = pid;
792	return (RB_FIND(session_tree, &session_tree, &s));
793}
794
795/*
796 * Construct an argument vector from a command line.
797 */
798char **
799construct_argv(char *command)
800{
801	int argc = 0;
802	char **argv = calloc((strlen(command) + 1) / 2 + 1, sizeof (char *));
803	static const char separators[] = " \t";
804
805	if (argv == NULL)
806		return (0);
807
808	if ((argv[argc++] = strtok(command, separators)) == 0) {
809		free(argv);
810		return (0);
811	}
812	while ((argv[argc++] = strtok(NULL, separators)))
813		continue;
814	return (argv);
815}
816
817/*
818 * Deallocate a session descriptor.
819 */
820void
821free_session(session_t *sp)
822{
823	free(sp->se_device);
824	if (sp->se_getty) {
825		free(sp->se_getty);
826		free(sp->se_getty_argv);
827	}
828	if (sp->se_window) {
829		free(sp->se_window);
830		free(sp->se_window_argv);
831	}
832	free(sp);
833}
834
835/*
836 * Allocate a new session descriptor.
837 */
838session_t *
839new_session(session_t *sprev, int session_index, struct ttyent *typ)
840{
841	session_t *sp;
842
843	if ((typ->ty_status & TTY_ON) == 0 ||
844	    typ->ty_name == 0 ||
845	    typ->ty_getty == 0)
846		return (0);
847
848	sp = calloc(1, sizeof (session_t));
849	if (sp == NULL)
850		err(1, "calloc");
851
852	sp->se_flags = SE_PRESENT;
853	sp->se_index = session_index;
854
855	if (asprintf(&sp->se_device, "%s%s", _PATH_DEV, typ->ty_name) == -1)
856		err(1, "asprintf");
857
858	if (setupargv(sp, typ) == 0) {
859		free_session(sp);
860		return (0);
861	}
862
863	sp->se_next = NULL;
864	if (sprev == NULL) {
865		sessions = sp;
866		sp->se_prev = NULL;
867	} else {
868		sprev->se_next = sp;
869		sp->se_prev = sprev;
870	}
871
872	return (sp);
873}
874
875/*
876 * Calculate getty and if useful window argv vectors.
877 */
878int
879setupargv(session_t *sp, struct ttyent *typ)
880{
881	if (sp->se_getty) {
882		free(sp->se_getty);
883		free(sp->se_getty_argv);
884	}
885	if (asprintf(&sp->se_getty, "%s %s", typ->ty_getty, typ->ty_name) == -1)
886		err(1, "asprintf");
887	sp->se_getty_argv = construct_argv(sp->se_getty);
888	if (sp->se_getty_argv == 0) {
889		warning("can't parse getty for port %s", sp->se_device);
890		free(sp->se_getty);
891		sp->se_getty = NULL;
892		return (0);
893	}
894	if (typ->ty_window) {
895		free(sp->se_window);
896		sp->se_window = strdup(typ->ty_window);
897		if (sp->se_window == NULL) {
898			warning("can't allocate window");
899			return (0);
900		}
901		sp->se_window_argv = construct_argv(sp->se_window);
902		if (sp->se_window_argv == NULL) {
903			warning("can't parse window for port %s",
904			    sp->se_device);
905			free(sp->se_window);
906			sp->se_window = NULL;
907			return (0);
908		}
909	}
910	return (1);
911}
912
913/*
914 * Walk the list of ttys and create sessions for each active line.
915 */
916state_t
917f_read_ttys(void)
918{
919	int session_index = 0;
920	session_t *sp, *snext;
921	struct ttyent *typ;
922
923	/*
924	 * Destroy any previous session state.
925	 * There shouldn't be any, but just in case...
926	 */
927	for (sp = sessions; sp; sp = snext) {
928		if (sp->se_process)
929			clear_session_logs(sp);
930		snext = sp->se_next;
931		free_session(sp);
932	}
933	sessions = NULL;
934
935	/*
936	 * Allocate a session entry for each active port.
937	 * Note that sp starts at 0.
938	 */
939	while ((typ = getttyent()))
940		if ((snext = new_session(sp, ++session_index, typ)))
941			sp = snext;
942
943	endttyent();
944
945	return multi_user;
946}
947
948/*
949 * Start a window system running.
950 */
951void
952start_window_system(session_t *sp)
953{
954	pid_t pid;
955	sigset_t mask;
956
957	if ((pid = fork()) == -1) {
958		emergency("can't fork for window system on port %s: %m",
959		    sp->se_device);
960		/* hope that getty fails and we can try again */
961		return;
962	}
963
964	if (pid)
965		return;
966
967	sigemptyset(&mask);
968	sigprocmask(SIG_SETMASK, &mask, NULL);
969
970	if (setsid() == -1)
971		emergency("setsid failed (window) %m");
972
973	setprocresources(RESOURCE_WINDOW);
974
975	execv(sp->se_window_argv[0], sp->se_window_argv);
976	stall("can't exec window system '%s' for port %s: %m",
977	    sp->se_window_argv[0], sp->se_device);
978	_exit(1);
979}
980
981/*
982 * Start a login session running.
983 * For first open, man-handle tty directly to determine if it
984 * really exists. It is not efficient to spawn gettys on devices
985 * that do not exist.
986 */
987pid_t
988start_getty(session_t *sp)
989{
990	pid_t pid;
991	sigset_t mask;
992	struct timespec current_time, elapsed;
993	int p[2], new = 1;
994
995	if (sp->se_flags & SE_DEVEXISTS)
996		new = 0;
997
998	if (new) {
999		if (pipe(p) == -1)
1000			return (-1);
1001	}
1002
1003	/*
1004	 * fork(), not vfork() -- we can't afford to block.
1005	 */
1006	if ((pid = fork()) == -1) {
1007		emergency("can't fork for getty on port %s: %m", sp->se_device);
1008		return (-1);
1009	}
1010
1011	if (pid) {
1012		if (new) {
1013			char c;
1014
1015			close(p[1]);
1016			if (read(p[0], &c, 1) != 1) {
1017				close(p[0]);
1018				return (-1);
1019			}
1020			close(p[0]);
1021			if (c == '1')
1022				sp->se_flags |= SE_DEVEXISTS;
1023			else
1024				sp->se_flags |= SE_SHUTDOWN;
1025		}
1026		return (pid);
1027	}
1028	if (new) {
1029		int fd;
1030
1031		close(p[0]);
1032		fd = open(sp->se_device, O_RDONLY | O_NONBLOCK, 0666);
1033		if (fd == -1 && (errno == ENXIO || errno == ENOENT ||
1034		    errno == EISDIR)) {
1035			(void)write(p[1], "0", 1);
1036			close(p[1]);
1037			_exit(1);
1038		}
1039		(void)write(p[1], "1", 1);
1040		close(p[1]);
1041		close(fd);
1042		sleep(1);
1043	}
1044
1045	if (timespecisset(&sp->se_started)) {
1046		clock_gettime(CLOCK_MONOTONIC, &current_time);
1047		timespecsub(&current_time, &sp->se_started, &elapsed);
1048		if (elapsed.tv_sec < GETTY_SPACING) {
1049			warning(
1050			    "getty repeating too quickly on port %s, sleeping",
1051			    sp->se_device);
1052			sleep(GETTY_SLEEP);
1053		}
1054	}
1055
1056	if (sp->se_window) {
1057		start_window_system(sp);
1058		sleep(WINDOW_WAIT);
1059	}
1060
1061	sigemptyset(&mask);
1062	sigprocmask(SIG_SETMASK, &mask, NULL);
1063
1064	setprocresources(RESOURCE_GETTY);
1065
1066	execv(sp->se_getty_argv[0], sp->se_getty_argv);
1067	stall("can't exec getty '%s' for port %s: %m",
1068	    sp->se_getty_argv[0], sp->se_device);
1069	_exit(1);
1070}
1071
1072/*
1073 * Collect exit status for a child.
1074 * If an exiting login, start a new login running.
1075 */
1076void
1077collect_child(pid_t pid)
1078{
1079	session_t *sp, *sprev, *snext;
1080
1081	if (sessions == NULL)
1082		return;
1083
1084	if ((sp = find_session(pid)) == NULL)
1085		return;
1086
1087	clear_session_logs(sp);
1088	login_fbtab(sp->se_device + sizeof(_PATH_DEV) - 1, 0, 0);
1089	del_session(sp);
1090	sp->se_process = 0;
1091
1092	if (sp->se_flags & SE_SHUTDOWN) {
1093		if ((sprev = sp->se_prev))
1094			sprev->se_next = sp->se_next;
1095		else
1096			sessions = sp->se_next;
1097		if ((snext = sp->se_next))
1098			snext->se_prev = sp->se_prev;
1099		free_session(sp);
1100		return;
1101	}
1102
1103	if ((pid = start_getty(sp)) == -1) {
1104		/* serious trouble */
1105		requested_transition = clean_ttys;
1106		return;
1107	}
1108
1109	sp->se_process = pid;
1110	clock_gettime(CLOCK_MONOTONIC, &sp->se_started);
1111	add_session(sp);
1112}
1113
1114/*
1115 * Catch a signal and request a state transition.
1116 */
1117void
1118transition_handler(int sig)
1119{
1120
1121	switch (sig) {
1122	case SIGHUP:
1123		requested_transition = clean_ttys;
1124		break;
1125	case SIGINT:
1126		requested_transition = do_reboot;
1127		break;
1128	case SIGTERM:
1129		requested_transition = death;
1130		break;
1131	case SIGUSR1:
1132		requested_transition = nice_death;
1133		break;
1134	case SIGUSR2:
1135		requested_transition = hard_death;
1136		break;
1137	case SIGTSTP:
1138		requested_transition = catatonia;
1139		break;
1140	default:
1141		requested_transition = 0;
1142		break;
1143	}
1144}
1145
1146/*
1147 * Take the system multiuser.
1148 */
1149state_t
1150f_multi_user(void)
1151{
1152	pid_t pid;
1153	session_t *sp;
1154
1155	/*
1156	 * If the administrator has not set the security level to -1
1157	 * to indicate that the kernel should not run multiuser in secure
1158	 * mode, and the run script has not set a higher level of security
1159	 * than level 1, then put the kernel into secure mode.
1160	 */
1161	if (requested_transition != catatonia) {
1162		if (getsecuritylevel() == 0)
1163			setsecuritylevel(1);
1164	}
1165
1166	requested_transition = 0;
1167
1168	for (sp = sessions; sp; sp = sp->se_next) {
1169		if (sp->se_process)
1170			continue;
1171		if ((pid = start_getty(sp)) == -1) {
1172			/* serious trouble */
1173			requested_transition = clean_ttys;
1174			break;
1175		}
1176		sp->se_process = pid;
1177		clock_gettime(CLOCK_MONOTONIC, &sp->se_started);
1178		add_session(sp);
1179	}
1180
1181	while (!requested_transition)
1182		if ((pid = waitpid(-1, NULL, 0)) != -1)
1183			collect_child(pid);
1184
1185	return requested_transition;
1186}
1187
1188/*
1189 * This is an n-squared algorithm.  We hope it isn't run often...
1190 */
1191state_t
1192f_clean_ttys(void)
1193{
1194	session_t *sp, *sprev;
1195	struct ttyent *typ;
1196	int session_index = 0;
1197	int devlen;
1198
1199	for (sp = sessions; sp; sp = sp->se_next)
1200		sp->se_flags &= ~SE_PRESENT;
1201
1202	devlen = sizeof(_PATH_DEV) - 1;
1203	while ((typ = getttyent())) {
1204		++session_index;
1205
1206		for (sprev = NULL, sp = sessions; sp; sprev = sp, sp = sp->se_next)
1207			if (strcmp(typ->ty_name, sp->se_device + devlen) == 0)
1208				break;
1209
1210		if (sp) {
1211			sp->se_flags |= SE_PRESENT;
1212			if (sp->se_index != session_index) {
1213				warning("port %s changed utmp index from %d to %d",
1214				    sp->se_device, sp->se_index,
1215				    session_index);
1216				sp->se_index = session_index;
1217			}
1218			if ((typ->ty_status & TTY_ON) == 0 ||
1219			    typ->ty_getty == 0) {
1220				sp->se_flags |= SE_SHUTDOWN;
1221				kill(sp->se_process, SIGHUP);
1222				continue;
1223			}
1224			sp->se_flags &= ~SE_SHUTDOWN;
1225			if (setupargv(sp, typ) == 0) {
1226				warning("can't parse getty for port %s",
1227				    sp->se_device);
1228				sp->se_flags |= SE_SHUTDOWN;
1229				kill(sp->se_process, SIGHUP);
1230			}
1231			continue;
1232		}
1233
1234		new_session(sprev, session_index, typ);
1235	}
1236
1237	endttyent();
1238
1239	for (sp = sessions; sp; sp = sp->se_next)
1240		if ((sp->se_flags & SE_PRESENT) == 0) {
1241			sp->se_flags |= SE_SHUTDOWN;
1242			kill(sp->se_process, SIGHUP);
1243		}
1244
1245	return multi_user;
1246}
1247
1248/*
1249 * Block further logins.
1250 */
1251state_t
1252f_catatonia(void)
1253{
1254	session_t *sp;
1255
1256	for (sp = sessions; sp; sp = sp->se_next)
1257		sp->se_flags |= SE_SHUTDOWN;
1258
1259	return multi_user;
1260}
1261
1262/*
1263 * Note SIGALRM.
1264 */
1265void
1266alrm_handler(int sig)
1267{
1268	clang = 1;
1269}
1270
1271int death_howto = RB_HALT;
1272
1273/*
1274 * Reboot the system.
1275 */
1276state_t
1277f_do_reboot(void)
1278{
1279	death_howto = RB_AUTOBOOT;
1280	return nice_death;
1281}
1282
1283/*
1284 * Bring the system down nicely, then we must powerdown because something
1285 * is very wrong.
1286 */
1287state_t
1288f_hard_death(void)
1289{
1290	death_howto |= RB_POWERDOWN;
1291	return nice_death;
1292}
1293
1294/*
1295 * Bring the system down to single user nicely, after run the shutdown script.
1296 */
1297state_t
1298f_nice_death(void)
1299{
1300	session_t *sp;
1301	int i;
1302	pid_t pid;
1303	static const int death_sigs[3] = { SIGHUP, SIGTERM, SIGKILL };
1304	int status;
1305
1306#ifdef CPU_LIDACTION
1307	int mib[] = {CTL_MACHDEP, CPU_LIDACTION};
1308	int lidaction = 0;
1309
1310	if ((death_howto & RB_POWERDOWN) &&
1311	    (sysctl(mib, 2, NULL, NULL, &lidaction,
1312		    sizeof(lidaction)) == -1) && (errno != EOPNOTSUPP))
1313			warning("cannot disable lid action");
1314#endif
1315
1316	for (sp = sessions; sp; sp = sp->se_next) {
1317		sp->se_flags &= ~SE_PRESENT;
1318		sp->se_flags |= SE_SHUTDOWN;
1319		kill(sp->se_process, SIGHUP);
1320	}
1321
1322	/* terminate the accounting process */
1323	acct(NULL);
1324
1325	/* NB: should send a message to the session logger to avoid blocking. */
1326	logwtmp("~", "shutdown", "");
1327
1328	if (access(_PATH_RUNCOM, R_OK) != -1) {
1329		struct sigaction sa;
1330
1331		switch ((pid = fork())) {
1332		case -1:
1333			break;
1334		case 0:
1335
1336			memset(&sa, 0, sizeof sa);
1337			sigemptyset(&sa.sa_mask);
1338			sa.sa_flags = 0;
1339			sa.sa_handler = SIG_IGN;
1340			(void) sigaction(SIGTSTP, &sa, NULL);
1341			(void) sigaction(SIGHUP, &sa, NULL);
1342
1343			setctty(_PATH_CONSOLE);
1344
1345			sigprocmask(SIG_SETMASK, &sa.sa_mask, NULL);
1346
1347			execl(_PATH_BSHELL, "sh", _PATH_RUNCOM, "shutdown",
1348			    (char *)NULL);
1349			stall("can't exec %s for %s %s: %m", _PATH_BSHELL,
1350			    _PATH_RUNCOM, "shutdown");
1351			_exit(1);
1352		default:
1353			waitpid(pid, &status, 0);
1354			if (WIFEXITED(status) && WEXITSTATUS(status) == 2)
1355				death_howto |= RB_POWERDOWN;
1356		}
1357	}
1358
1359	for (i = 0; i < 3; ++i) {
1360		if (kill(-1, death_sigs[i]) == -1 && errno == ESRCH)
1361			goto die;
1362
1363		clang = 0;
1364		alarm(DEATH_WATCH);
1365		do {
1366			if ((pid = waitpid(-1, NULL, 0)) != -1)
1367				collect_child(pid);
1368		} while (clang == 0 && errno != ECHILD);
1369
1370		if (errno == ECHILD)
1371			goto die;
1372	}
1373
1374	warning("some processes would not die; ps axl advised");
1375
1376die:
1377	reboot(death_howto);
1378
1379	/* ... and if that fails.. oh well */
1380	return single_user;
1381}
1382
1383/*
1384 * Bring the system down to single user.
1385 */
1386state_t
1387f_death(void)
1388{
1389	session_t *sp;
1390	int i;
1391	pid_t pid;
1392	static const int death_sigs[3] = { SIGHUP, SIGTERM, SIGKILL };
1393
1394	/* terminate the accounting process */
1395	acct(NULL);
1396
1397	for (sp = sessions; sp; sp = sp->se_next)
1398		sp->se_flags |= SE_SHUTDOWN;
1399
1400	/* NB: should send a message to the session logger to avoid blocking. */
1401	logwtmp("~", "shutdown", "");
1402
1403	for (i = 0; i < 3; ++i) {
1404		if (kill(-1, death_sigs[i]) == -1 && errno == ESRCH)
1405			return single_user;
1406
1407		clang = 0;
1408		alarm(DEATH_WATCH);
1409		do {
1410			if ((pid = waitpid(-1, NULL, 0)) != -1)
1411				collect_child(pid);
1412		} while (clang == 0 && errno != ECHILD);
1413
1414		if (errno == ECHILD)
1415			return single_user;
1416	}
1417
1418	warning("some processes would not die; ps axl advised");
1419
1420	return single_user;
1421}
1422
1423void
1424setprocresources(char *class)
1425{
1426	login_cap_t *lc;
1427
1428	if ((lc = login_getclass(class)) != NULL) {
1429		setusercontext(lc, NULL, 0,
1430		    LOGIN_SETPRIORITY|LOGIN_SETRESOURCES|LOGIN_SETUMASK);
1431		login_close(lc);
1432	}
1433}
1434