init.c revision 1.67 
1/*	$OpenBSD: init.c,v 1.67 2018/01/31 15:57:44 cheloha 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);
94void badsys(int);
95
96typedef enum {
97	invalid_state,
98	single_user,
99	runcom,
100	read_ttys,
101	multi_user,
102	clean_ttys,
103	catatonia,
104	death,
105	do_reboot,
106	hard_death,
107	nice_death
108} state_t;
109typedef state_t (*state_func_t)(void);
110
111state_t f_single_user(void);
112state_t f_runcom(void);
113state_t f_read_ttys(void);
114state_t f_multi_user(void);
115state_t f_clean_ttys(void);
116state_t f_catatonia(void);
117state_t f_death(void);
118state_t f_do_reboot(void);
119state_t f_hard_death(void);
120state_t f_nice_death(void);
121
122state_func_t state_funcs[] = {
123	NULL,
124	f_single_user,
125	f_runcom,
126	f_read_ttys,
127	f_multi_user,
128	f_clean_ttys,
129	f_catatonia,
130	f_death,
131	f_do_reboot,
132	f_hard_death,
133	f_nice_death
134};
135
136enum { AUTOBOOT, FASTBOOT } runcom_mode = AUTOBOOT;
137
138void transition(state_t);
139volatile sig_atomic_t requested_transition = DEFAULT_STATE;
140
141void setctty(char *);
142
143typedef struct init_session {
144	int	se_index;		/* index of entry in ttys file */
145	pid_t	se_process;		/* controlling process */
146	struct	timespec se_started;	/* used to avoid thrashing */
147	int	se_flags;		/* status of session */
148#define	SE_SHUTDOWN	0x1		/* session won't be restarted */
149#define	SE_PRESENT	0x2		/* session is in /etc/ttys */
150#define	SE_DEVEXISTS	0x4		/* open does not result in ENODEV */
151	char	*se_device;		/* filename of port */
152	char	*se_getty;		/* what to run on that port */
153	char	**se_getty_argv;	/* pre-parsed argument array */
154	char	*se_window;		/* window system (started only once) */
155	char	**se_window_argv;	/* pre-parsed argument array */
156	struct	init_session *se_prev;
157	struct	init_session *se_next;
158	RB_ENTRY(init_session) se_entry;
159} session_t;
160
161static int cmp_sessions(session_t *, session_t *);
162RB_HEAD(session_tree, init_session) session_tree = RB_INITIALIZER(session_tree);
163RB_PROTOTYPE(session_tree, init_session, se_entry, cmp_sessions);
164RB_GENERATE(session_tree, init_session, se_entry, cmp_sessions);
165
166void free_session(session_t *);
167session_t *new_session(session_t *, int, struct ttyent *);
168session_t *sessions;
169
170char **construct_argv(char *);
171void start_window_system(session_t *);
172void collect_child(pid_t);
173pid_t start_getty(session_t *);
174void transition_handler(int);
175void alrm_handler(int);
176void setsecuritylevel(int);
177void setprocresources(char *);
178int getsecuritylevel(void);
179int setupargv(session_t *, struct ttyent *);
180int clang;
181
182void clear_session_logs(session_t *);
183
184void add_session(session_t *);
185void del_session(session_t *);
186session_t *find_session(pid_t);
187
188/*
189 * The mother of all processes.
190 */
191int
192main(int argc, char *argv[])
193{
194	int c, fd;
195	struct sigaction sa;
196	sigset_t mask;
197
198	/* Dispose of random users. */
199	if (getuid() != 0) {
200		(void)fprintf(stderr, "init: %s\n", strerror(EPERM));
201		exit (1);
202	}
203
204	/* System V users like to reexec init. */
205	if (getpid() != 1) {
206		(void)fprintf(stderr, "init: already running\n");
207		exit (1);
208	}
209
210	/*
211	 * Paranoia.
212	 */
213	if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
214		(void)dup2(fd, STDIN_FILENO);
215		(void)dup2(fd, STDOUT_FILENO);
216		(void)dup2(fd, STDERR_FILENO);
217		if (fd > 2)
218			(void)close(fd);
219	}
220
221	/*
222	 * Note that this does NOT open a file...
223	 * Does 'init' deserve its own facility number?
224	 */
225	openlog("init", LOG_CONS|LOG_ODELAY, LOG_AUTH);
226
227	/*
228	 * Create an initial session.
229	 */
230	if (setsid() < 0)
231		warning("initial setsid() failed: %m");
232
233	/*
234	 * Establish an initial user so that programs running
235	 * single user do not freak out and die (like passwd).
236	 */
237	if (setlogin("root") < 0)
238		warning("setlogin() failed: %m");
239
240	/*
241	 * This code assumes that we always get arguments through flags,
242	 * never through bits set in some random machine register.
243	 */
244	while ((c = getopt(argc, argv, "sf")) != -1)
245		switch (c) {
246		case 's':
247			requested_transition = single_user;
248			break;
249		case 'f':
250			runcom_mode = FASTBOOT;
251			break;
252		default:
253			warning("unrecognized flag '-%c'", c);
254			break;
255		}
256
257	if (optind != argc)
258		warning("ignoring excess arguments");
259
260	/*
261	 * We catch or block signals rather than ignore them,
262	 * so that they get reset on exec.
263	 */
264	handle(badsys, SIGSYS, 0);
265	handle(disaster, SIGABRT, SIGFPE, SIGILL, SIGSEGV,
266	    SIGBUS, SIGXCPU, SIGXFSZ, 0);
267	handle(transition_handler, SIGHUP, SIGINT, SIGTERM, SIGTSTP,
268            SIGUSR1, SIGUSR2, 0);
269	handle(alrm_handler, SIGALRM, 0);
270	sigfillset(&mask);
271	delset(&mask, SIGABRT, SIGFPE, SIGILL, SIGSEGV, SIGBUS, SIGSYS,
272	    SIGXCPU, SIGXFSZ, SIGHUP, SIGINT, SIGTERM, SIGUSR1, SIGUSR2,
273	    SIGTSTP, SIGALRM, 0);
274	sigprocmask(SIG_SETMASK, &mask, NULL);
275	memset(&sa, 0, sizeof sa);
276	sigemptyset(&sa.sa_mask);
277	sa.sa_flags = 0;
278	sa.sa_handler = SIG_IGN;
279	(void) sigaction(SIGTTIN, &sa, NULL);
280	(void) sigaction(SIGTTOU, &sa, NULL);
281
282	/*
283	 * Start the state machine.
284	 */
285	transition(requested_transition);
286
287	/*
288	 * Should never reach here.
289	 */
290	exit(1);
291}
292
293/*
294 * Associate a function with a signal handler.
295 */
296void
297handle(sig_t handler, ...)
298{
299	int sig;
300	struct sigaction sa;
301	sigset_t mask_everything;
302	va_list ap;
303
304	va_start(ap, handler);
305
306	memset(&sa, 0, sizeof sa);
307	sa.sa_handler = handler;
308	sigfillset(&mask_everything);
309
310	while ((sig = va_arg(ap, int))) {
311		sa.sa_mask = mask_everything;
312		/* XXX SA_RESTART? */
313		sa.sa_flags = sig == SIGCHLD ? SA_NOCLDSTOP : 0;
314		sigaction(sig, &sa, NULL);
315	}
316	va_end(ap);
317}
318
319/*
320 * Delete a set of signals from a mask.
321 */
322void
323delset(sigset_t *maskp, ...)
324{
325	int sig;
326	va_list ap;
327
328	va_start(ap, maskp);
329	while ((sig = va_arg(ap, int)))
330		sigdelset(maskp, sig);
331	va_end(ap);
332}
333
334/*
335 * Log a message and sleep for a while (to give someone an opportunity
336 * to read it and to save log or hardcopy output if the problem is chronic).
337 * NB: should send a message to the session logger to avoid blocking.
338 */
339void
340stall(char *message, ...)
341{
342	va_list ap;
343
344	va_start(ap, message);
345	vsyslog(LOG_ALERT, message, ap);
346	va_end(ap);
347	closelog();
348	sleep(STALL_TIMEOUT);
349}
350
351/*
352 * Like stall(), but doesn't sleep.
353 * If cpp had variadic macros, the two functions could be #defines for another.
354 * NB: should send a message to the session logger to avoid blocking.
355 */
356void
357warning(char *message, ...)
358{
359	va_list ap;
360
361	va_start(ap, message);
362	vsyslog(LOG_ALERT, message, ap);
363	va_end(ap);
364	closelog();
365}
366
367/*
368 * Log an emergency message.
369 * NB: should send a message to the session logger to avoid blocking.
370 */
371void
372emergency(char *message, ...)
373{
374	struct syslog_data sdata = SYSLOG_DATA_INIT;
375	va_list ap;
376
377	va_start(ap, message);
378	vsyslog_r(LOG_EMERG, &sdata, message, ap);
379	va_end(ap);
380}
381
382/*
383 * Catch a SIGSYS signal.
384 *
385 * These may arise if a system does not support sysctl.
386 * We tolerate up to 25 of these, then throw in the towel.
387 */
388void
389badsys(int sig)
390{
391	static int badcount = 0;
392
393	if (badcount++ < 25)
394		return;
395	disaster(sig);
396}
397
398/*
399 * Catch an unexpected signal.
400 */
401void
402disaster(int sig)
403{
404	emergency("fatal signal: %s", strsignal(sig));
405
406	sleep(STALL_TIMEOUT);
407	_exit(sig);		/* reboot */
408}
409
410/*
411 * Get the security level of the kernel.
412 */
413int
414getsecuritylevel(void)
415{
416#ifdef KERN_SECURELVL
417	int name[2], curlevel;
418	size_t len;
419
420	name[0] = CTL_KERN;
421	name[1] = KERN_SECURELVL;
422	len = sizeof curlevel;
423	if (sysctl(name, 2, &curlevel, &len, NULL, 0) == -1) {
424		emergency("cannot get kernel security level: %s",
425		    strerror(errno));
426		return (-1);
427	}
428	return (curlevel);
429#else
430	return (-1);
431#endif
432}
433
434/*
435 * Set the security level of the kernel.
436 */
437void
438setsecuritylevel(int newlevel)
439{
440#ifdef KERN_SECURELVL
441	int name[2], curlevel;
442
443	curlevel = getsecuritylevel();
444	if (newlevel == curlevel)
445		return;
446	name[0] = CTL_KERN;
447	name[1] = KERN_SECURELVL;
448	if (sysctl(name, 2, NULL, NULL, &newlevel, sizeof newlevel) == -1) {
449		emergency(
450		    "cannot change kernel security level from %d to %d: %s",
451		    curlevel, newlevel, strerror(errno));
452		return;
453	}
454#ifdef SECURE
455	warning("kernel security level changed from %d to %d",
456	    curlevel, newlevel);
457#endif
458#endif
459}
460
461/*
462 * Change states in the finite state machine.
463 * The initial state is passed as an argument.
464 */
465void
466transition(state_t s)
467{
468	for (;;)
469		s = (*state_funcs[s])();
470}
471
472/*
473 * Close out the accounting files for a login session.
474 * NB: should send a message to the session logger to avoid blocking.
475 */
476void
477clear_session_logs(session_t *sp)
478{
479	char *line = sp->se_device + sizeof(_PATH_DEV) - 1;
480
481	if (logout(line))
482		logwtmp(line, "", "");
483}
484
485/*
486 * Start a session and allocate a controlling terminal.
487 * Only called by children of init after forking.
488 */
489void
490setctty(char *name)
491{
492	int fd;
493
494	(void) revoke(name);
495	sleep(2);			/* leave DTR low */
496	if ((fd = open(name, O_RDWR)) == -1) {
497		stall("can't open %s: %m", name);
498		_exit(1);
499	}
500	if (login_tty(fd) == -1) {
501		stall("can't get %s for controlling terminal: %m", name);
502		_exit(1);
503	}
504}
505
506/*
507 * Bring the system up single user.
508 */
509state_t
510f_single_user(void)
511{
512	pid_t pid, wpid;
513	int status;
514	sigset_t mask;
515	char shell[PATH_MAX];		/* Allocate space here */
516	char name[PATH_MAX];		/* Name (argv[0]) of shell */
517	char *argv[2];
518#ifdef SECURE
519	struct ttyent *typ;
520	struct passwd *pp;
521	static const char banner[] =
522		"Enter root password, or ^D to go multi-user\n";
523	char *clear;
524	char pbuf[1024];
525#endif
526
527	/* Init shell and name */
528	strlcpy(shell, _PATH_BSHELL, sizeof shell);
529	strlcpy(name, "-sh", sizeof name);
530
531	/*
532	 * If the kernel is in secure mode, downgrade it to insecure mode.
533	 */
534	if (getsecuritylevel() > 0)
535		setsecuritylevel(0);
536
537	if ((pid = fork()) == 0) {
538		/*
539		 * Start the single user session.
540		 */
541		setctty(_PATH_CONSOLE);
542
543#ifdef SECURE
544		/*
545		 * Check the root password.
546		 * We don't care if the console is 'on' by default;
547		 * it's the only tty that can be 'off' and 'secure'.
548		 */
549		typ = getttynam("console");
550		pp = getpwnam_shadow("root");
551		if (typ && (typ->ty_status & TTY_SECURE) == 0 && pp &&
552		    *pp->pw_passwd) {
553			write(STDERR_FILENO, banner, sizeof banner - 1);
554			for (;;) {
555				int ok = 0;
556				clear = readpassphrase("Password:", pbuf,
557				    sizeof(pbuf), RPP_ECHO_OFF);
558				if (clear == NULL || *clear == '\0')
559					_exit(0);
560				if (crypt_checkpass(clear, pp->pw_passwd) == 0)
561					ok = 1;
562				explicit_bzero(pbuf, sizeof(pbuf));
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 * Compare session keys.
771 */
772static int
773cmp_sessions(session_t *sp1, session_t *sp2)
774{
775	if (sp1->se_process < sp2->se_process)
776		return (-1);
777	if (sp1->se_process > sp2->se_process)
778		return (1);
779	return (0);
780}
781
782/*
783 * Add a new login session.
784 */
785void
786add_session(session_t *sp)
787{
788	if (RB_INSERT(session_tree, &session_tree, sp) != NULL)
789		emergency("insert %d: %s", sp->se_process, strerror(errno));
790}
791
792/*
793 * Delete an old login session.
794 */
795void
796del_session(session_t *sp)
797{
798	RB_REMOVE(session_tree, &session_tree, sp);
799}
800
801/*
802 * Look up a login session by pid.
803 */
804session_t *
805find_session(pid_t pid)
806{
807	struct init_session s;
808
809	s.se_process = pid;
810	return (RB_FIND(session_tree, &session_tree, &s));
811}
812
813/*
814 * Construct an argument vector from a command line.
815 */
816char **
817construct_argv(char *command)
818{
819	int argc = 0;
820	char **argv = calloc((strlen(command) + 1) / 2 + 1, sizeof (char *));
821	static const char separators[] = " \t";
822
823	if (argv == NULL)
824		return (0);
825
826	if ((argv[argc++] = strtok(command, separators)) == 0) {
827		free(argv);
828		return (0);
829	}
830	while ((argv[argc++] = strtok(NULL, separators)))
831		continue;
832	return (argv);
833}
834
835/*
836 * Deallocate a session descriptor.
837 */
838void
839free_session(session_t *sp)
840{
841	free(sp->se_device);
842	if (sp->se_getty) {
843		free(sp->se_getty);
844		free(sp->se_getty_argv);
845	}
846	if (sp->se_window) {
847		free(sp->se_window);
848		free(sp->se_window_argv);
849	}
850	free(sp);
851}
852
853/*
854 * Allocate a new session descriptor.
855 */
856session_t *
857new_session(session_t *sprev, int session_index, struct ttyent *typ)
858{
859	session_t *sp;
860
861	if ((typ->ty_status & TTY_ON) == 0 ||
862	    typ->ty_name == 0 ||
863	    typ->ty_getty == 0)
864		return (0);
865
866	sp = calloc(1, sizeof (session_t));
867	if (sp == NULL)
868		err(1, "calloc");
869
870	sp->se_flags = SE_PRESENT;
871	sp->se_index = session_index;
872
873	if (asprintf(&sp->se_device, "%s%s", _PATH_DEV, typ->ty_name) == -1)
874		err(1, "asprintf");
875
876	if (setupargv(sp, typ) == 0) {
877		free_session(sp);
878		return (0);
879	}
880
881	sp->se_next = NULL;
882	if (sprev == NULL) {
883		sessions = sp;
884		sp->se_prev = NULL;
885	} else {
886		sprev->se_next = sp;
887		sp->se_prev = sprev;
888	}
889
890	return (sp);
891}
892
893/*
894 * Calculate getty and if useful window argv vectors.
895 */
896int
897setupargv(session_t *sp, struct ttyent *typ)
898{
899	if (sp->se_getty) {
900		free(sp->se_getty);
901		free(sp->se_getty_argv);
902	}
903	if (asprintf(&sp->se_getty, "%s %s", typ->ty_getty, typ->ty_name) == -1)
904		err(1, "asprintf");
905	sp->se_getty_argv = construct_argv(sp->se_getty);
906	if (sp->se_getty_argv == 0) {
907		warning("can't parse getty for port %s", sp->se_device);
908		free(sp->se_getty);
909		sp->se_getty = NULL;
910		return (0);
911	}
912	if (typ->ty_window) {
913		free(sp->se_window);
914		sp->se_window = strdup(typ->ty_window);
915		if (sp->se_window == NULL) {
916			warning("can't allocate window");
917			return (0);
918		}
919		sp->se_window_argv = construct_argv(sp->se_window);
920		if (sp->se_window_argv == NULL) {
921			warning("can't parse window for port %s",
922			    sp->se_device);
923			free(sp->se_window);
924			sp->se_window = NULL;
925			return (0);
926		}
927	}
928	return (1);
929}
930
931/*
932 * Walk the list of ttys and create sessions for each active line.
933 */
934state_t
935f_read_ttys(void)
936{
937	int session_index = 0;
938	session_t *sp, *snext;
939	struct ttyent *typ;
940
941	/*
942	 * Destroy any previous session state.
943	 * There shouldn't be any, but just in case...
944	 */
945	for (sp = sessions; sp; sp = snext) {
946		if (sp->se_process)
947			clear_session_logs(sp);
948		snext = sp->se_next;
949		free_session(sp);
950	}
951	sessions = NULL;
952
953	/*
954	 * Allocate a session entry for each active port.
955	 * Note that sp starts at 0.
956	 */
957	while ((typ = getttyent()))
958		if ((snext = new_session(sp, ++session_index, typ)))
959			sp = snext;
960
961	endttyent();
962
963	return multi_user;
964}
965
966/*
967 * Start a window system running.
968 */
969void
970start_window_system(session_t *sp)
971{
972	pid_t pid;
973	sigset_t mask;
974
975	if ((pid = fork()) == -1) {
976		emergency("can't fork for window system on port %s: %m",
977		    sp->se_device);
978		/* hope that getty fails and we can try again */
979		return;
980	}
981
982	if (pid)
983		return;
984
985	sigemptyset(&mask);
986	sigprocmask(SIG_SETMASK, &mask, NULL);
987
988	if (setsid() < 0)
989		emergency("setsid failed (window) %m");
990
991	setprocresources(RESOURCE_WINDOW);
992
993	execv(sp->se_window_argv[0], sp->se_window_argv);
994	stall("can't exec window system '%s' for port %s: %m",
995	    sp->se_window_argv[0], sp->se_device);
996	_exit(1);
997}
998
999/*
1000 * Start a login session running.
1001 * For first open, man-handle tty directly to determine if it
1002 * really exists. It is not efficient to spawn gettys on devices
1003 * that do not exist.
1004 */
1005pid_t
1006start_getty(session_t *sp)
1007{
1008	pid_t pid;
1009	sigset_t mask;
1010	struct timespec current_time, elapsed;
1011	int p[2], new = 1;
1012
1013	if (sp->se_flags & SE_DEVEXISTS)
1014		new = 0;
1015
1016	if (new) {
1017		if (pipe(p) == -1)
1018			return (-1);
1019	}
1020
1021	/*
1022	 * fork(), not vfork() -- we can't afford to block.
1023	 */
1024	if ((pid = fork()) == -1) {
1025		emergency("can't fork for getty on port %s: %m", sp->se_device);
1026		return (-1);
1027	}
1028
1029	if (pid) {
1030		if (new) {
1031			char c;
1032
1033			close(p[1]);
1034			if (read(p[0], &c, 1) != 1) {
1035				close(p[0]);
1036				return (-1);
1037			}
1038			close(p[0]);
1039			if (c == '1')
1040				sp->se_flags |= SE_DEVEXISTS;
1041			else
1042				sp->se_flags |= SE_SHUTDOWN;
1043		}
1044		return (pid);
1045	}
1046	if (new) {
1047		int fd;
1048
1049		close(p[0]);
1050		fd = open(sp->se_device, O_RDONLY | O_NONBLOCK, 0666);
1051		if (fd == -1 && (errno == ENXIO || errno == ENOENT ||
1052		    errno == EISDIR)) {
1053			(void)write(p[1], "0", 1);
1054			close(p[1]);
1055			_exit(1);
1056		}
1057		(void)write(p[1], "1", 1);
1058		close(p[1]);
1059		close(fd);
1060		sleep(1);
1061	}
1062
1063	if (timespecisset(&sp->se_started)) {
1064		clock_gettime(CLOCK_MONOTONIC, &current_time);
1065		timespecsub(&current_time, &sp->se_started, &elapsed);
1066		if (elapsed.tv_sec < GETTY_SPACING) {
1067			warning(
1068			    "getty repeating too quickly on port %s, sleeping",
1069			    sp->se_device);
1070			sleep(GETTY_SLEEP);
1071		}
1072	}
1073
1074	if (sp->se_window) {
1075		start_window_system(sp);
1076		sleep(WINDOW_WAIT);
1077	}
1078
1079	sigemptyset(&mask);
1080	sigprocmask(SIG_SETMASK, &mask, NULL);
1081
1082	setprocresources(RESOURCE_GETTY);
1083
1084	execv(sp->se_getty_argv[0], sp->se_getty_argv);
1085	stall("can't exec getty '%s' for port %s: %m",
1086	    sp->se_getty_argv[0], sp->se_device);
1087	_exit(1);
1088}
1089
1090/*
1091 * Collect exit status for a child.
1092 * If an exiting login, start a new login running.
1093 */
1094void
1095collect_child(pid_t pid)
1096{
1097	session_t *sp, *sprev, *snext;
1098
1099	if (sessions == NULL)
1100		return;
1101
1102	if ((sp = find_session(pid)) == NULL)
1103		return;
1104
1105	clear_session_logs(sp);
1106	login_fbtab(sp->se_device + sizeof(_PATH_DEV) - 1, 0, 0);
1107	del_session(sp);
1108	sp->se_process = 0;
1109
1110	if (sp->se_flags & SE_SHUTDOWN) {
1111		if ((sprev = sp->se_prev))
1112			sprev->se_next = sp->se_next;
1113		else
1114			sessions = sp->se_next;
1115		if ((snext = sp->se_next))
1116			snext->se_prev = sp->se_prev;
1117		free_session(sp);
1118		return;
1119	}
1120
1121	if ((pid = start_getty(sp)) == -1) {
1122		/* serious trouble */
1123		requested_transition = clean_ttys;
1124		return;
1125	}
1126
1127	sp->se_process = pid;
1128	clock_gettime(CLOCK_MONOTONIC, &sp->se_started);
1129	add_session(sp);
1130}
1131
1132/*
1133 * Catch a signal and request a state transition.
1134 */
1135void
1136transition_handler(int sig)
1137{
1138
1139	switch (sig) {
1140	case SIGHUP:
1141		requested_transition = clean_ttys;
1142		break;
1143	case SIGINT:
1144		requested_transition = do_reboot;
1145		break;
1146	case SIGTERM:
1147		requested_transition = death;
1148		break;
1149	case SIGUSR1:
1150		requested_transition = nice_death;
1151		break;
1152	case SIGUSR2:
1153		requested_transition = hard_death;
1154		break;
1155	case SIGTSTP:
1156		requested_transition = catatonia;
1157		break;
1158	default:
1159		requested_transition = 0;
1160		break;
1161	}
1162}
1163
1164/*
1165 * Take the system multiuser.
1166 */
1167state_t
1168f_multi_user(void)
1169{
1170	pid_t pid;
1171	session_t *sp;
1172
1173	/*
1174	 * If the administrator has not set the security level to -1
1175	 * to indicate that the kernel should not run multiuser in secure
1176	 * mode, and the run script has not set a higher level of security
1177	 * than level 1, then put the kernel into secure mode.
1178	 */
1179	if (requested_transition != catatonia) {
1180		if (getsecuritylevel() == 0)
1181			setsecuritylevel(1);
1182	}
1183
1184	requested_transition = 0;
1185
1186	for (sp = sessions; sp; sp = sp->se_next) {
1187		if (sp->se_process)
1188			continue;
1189		if ((pid = start_getty(sp)) == -1) {
1190			/* serious trouble */
1191			requested_transition = clean_ttys;
1192			break;
1193		}
1194		sp->se_process = pid;
1195		clock_gettime(CLOCK_MONOTONIC, &sp->se_started);
1196		add_session(sp);
1197	}
1198
1199	while (!requested_transition)
1200		if ((pid = waitpid(-1, NULL, 0)) != -1)
1201			collect_child(pid);
1202
1203	return requested_transition;
1204}
1205
1206/*
1207 * This is an n-squared algorithm.  We hope it isn't run often...
1208 */
1209state_t
1210f_clean_ttys(void)
1211{
1212	session_t *sp, *sprev;
1213	struct ttyent *typ;
1214	int session_index = 0;
1215	int devlen;
1216
1217	for (sp = sessions; sp; sp = sp->se_next)
1218		sp->se_flags &= ~SE_PRESENT;
1219
1220	devlen = sizeof(_PATH_DEV) - 1;
1221	while ((typ = getttyent())) {
1222		++session_index;
1223
1224		for (sprev = NULL, sp = sessions; sp; sprev = sp, sp = sp->se_next)
1225			if (strcmp(typ->ty_name, sp->se_device + devlen) == 0)
1226				break;
1227
1228		if (sp) {
1229			sp->se_flags |= SE_PRESENT;
1230			if (sp->se_index != session_index) {
1231				warning("port %s changed utmp index from %d to %d",
1232				    sp->se_device, sp->se_index,
1233				    session_index);
1234				sp->se_index = session_index;
1235			}
1236			if ((typ->ty_status & TTY_ON) == 0 ||
1237			    typ->ty_getty == 0) {
1238				sp->se_flags |= SE_SHUTDOWN;
1239				kill(sp->se_process, SIGHUP);
1240				continue;
1241			}
1242			sp->se_flags &= ~SE_SHUTDOWN;
1243			if (setupargv(sp, typ) == 0) {
1244				warning("can't parse getty for port %s",
1245				    sp->se_device);
1246				sp->se_flags |= SE_SHUTDOWN;
1247				kill(sp->se_process, SIGHUP);
1248			}
1249			continue;
1250		}
1251
1252		new_session(sprev, session_index, typ);
1253	}
1254
1255	endttyent();
1256
1257	for (sp = sessions; sp; sp = sp->se_next)
1258		if ((sp->se_flags & SE_PRESENT) == 0) {
1259			sp->se_flags |= SE_SHUTDOWN;
1260			kill(sp->se_process, SIGHUP);
1261		}
1262
1263	return multi_user;
1264}
1265
1266/*
1267 * Block further logins.
1268 */
1269state_t
1270f_catatonia(void)
1271{
1272	session_t *sp;
1273
1274	for (sp = sessions; sp; sp = sp->se_next)
1275		sp->se_flags |= SE_SHUTDOWN;
1276
1277	return multi_user;
1278}
1279
1280/*
1281 * Note SIGALRM.
1282 */
1283void
1284alrm_handler(int sig)
1285{
1286	clang = 1;
1287}
1288
1289int death_howto = RB_HALT;
1290
1291/*
1292 * Reboot the system.
1293 */
1294state_t
1295f_do_reboot(void)
1296{
1297	death_howto = RB_AUTOBOOT;
1298	return nice_death;
1299}
1300
1301/*
1302 * Bring the system down nicely, then we must powerdown because something
1303 * is very wrong.
1304 */
1305state_t
1306f_hard_death(void)
1307{
1308	death_howto |= RB_POWERDOWN;
1309	return nice_death;
1310}
1311
1312/*
1313 * Bring the system down to single user nicely, after run the shutdown script.
1314 */
1315state_t
1316f_nice_death(void)
1317{
1318	session_t *sp;
1319	int i;
1320	pid_t pid;
1321	static const int death_sigs[3] = { SIGHUP, SIGTERM, SIGKILL };
1322	int status;
1323
1324#ifdef CPU_LIDACTION
1325	int mib[] = {CTL_MACHDEP, CPU_LIDACTION};
1326	int lidaction = 0;
1327
1328	if ((death_howto & RB_POWERDOWN) &&
1329	    (sysctl(mib, 2, NULL, NULL, &lidaction,
1330		    sizeof(lidaction)) == -1) && (errno != EOPNOTSUPP))
1331			warning("cannot disable lid action");
1332#endif
1333
1334	for (sp = sessions; sp; sp = sp->se_next) {
1335		sp->se_flags &= ~SE_PRESENT;
1336		sp->se_flags |= SE_SHUTDOWN;
1337		kill(sp->se_process, SIGHUP);
1338	}
1339
1340	/* terminate the accounting process */
1341	acct(NULL);
1342
1343	/* NB: should send a message to the session logger to avoid blocking. */
1344	logwtmp("~", "shutdown", "");
1345
1346	if (access(_PATH_RUNCOM, R_OK) != -1) {
1347		struct sigaction sa;
1348
1349		switch ((pid = fork())) {
1350		case -1:
1351			break;
1352		case 0:
1353
1354			memset(&sa, 0, sizeof sa);
1355			sigemptyset(&sa.sa_mask);
1356			sa.sa_flags = 0;
1357			sa.sa_handler = SIG_IGN;
1358			(void) sigaction(SIGTSTP, &sa, NULL);
1359			(void) sigaction(SIGHUP, &sa, NULL);
1360
1361			setctty(_PATH_CONSOLE);
1362
1363			sigprocmask(SIG_SETMASK, &sa.sa_mask, NULL);
1364
1365			execl(_PATH_BSHELL, "sh", _PATH_RUNCOM, "shutdown",
1366			    (char *)NULL);
1367			stall("can't exec %s for %s %s: %m", _PATH_BSHELL,
1368			    _PATH_RUNCOM, "shutdown");
1369			_exit(1);
1370		default:
1371			waitpid(pid, &status, 0);
1372			if (WIFEXITED(status) && WEXITSTATUS(status) == 2)
1373				death_howto |= RB_POWERDOWN;
1374		}
1375	}
1376
1377	for (i = 0; i < 3; ++i) {
1378		if (kill(-1, death_sigs[i]) == -1 && errno == ESRCH)
1379			goto die;
1380
1381		clang = 0;
1382		alarm(DEATH_WATCH);
1383		do {
1384			if ((pid = waitpid(-1, NULL, 0)) != -1)
1385				collect_child(pid);
1386		} while (clang == 0 && errno != ECHILD);
1387
1388		if (errno == ECHILD)
1389			goto die;
1390	}
1391
1392	warning("some processes would not die; ps axl advised");
1393
1394die:
1395	reboot(death_howto);
1396
1397	/* ... and if that fails.. oh well */
1398	return single_user;
1399}
1400
1401/*
1402 * Bring the system down to single user.
1403 */
1404state_t
1405f_death(void)
1406{
1407	session_t *sp;
1408	int i;
1409	pid_t pid;
1410	static const int death_sigs[3] = { SIGHUP, SIGTERM, SIGKILL };
1411
1412	/* terminate the accounting process */
1413	acct(NULL);
1414
1415	for (sp = sessions; sp; sp = sp->se_next)
1416		sp->se_flags |= SE_SHUTDOWN;
1417
1418	/* NB: should send a message to the session logger to avoid blocking. */
1419	logwtmp("~", "shutdown", "");
1420
1421	for (i = 0; i < 3; ++i) {
1422		if (kill(-1, death_sigs[i]) == -1 && errno == ESRCH)
1423			return single_user;
1424
1425		clang = 0;
1426		alarm(DEATH_WATCH);
1427		do {
1428			if ((pid = waitpid(-1, NULL, 0)) != -1)
1429				collect_child(pid);
1430		} while (clang == 0 && errno != ECHILD);
1431
1432		if (errno == ECHILD)
1433			return single_user;
1434	}
1435
1436	warning("some processes would not die; ps axl advised");
1437
1438	return single_user;
1439}
1440
1441void
1442setprocresources(char *class)
1443{
1444	login_cap_t *lc;
1445
1446	if ((lc = login_getclass(class)) != NULL) {
1447		setusercontext(lc, NULL, 0,
1448		    LOGIN_SETPRIORITY|LOGIN_SETRESOURCES|LOGIN_SETUMASK);
1449		login_close(lc);
1450	}
1451}
1452