xref: /titanic_52/usr/src/cmd/ttymon/ttymon.c (revision b819cea2f73f98c5662230cc9affc8cc84f77fcf) 
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
27 /*	  All Rights Reserved  	*/
28 
29 #include <stdio_ext.h>
30 #include <stdlib.h>
31 #include <fcntl.h>
32 #include <errno.h>
33 #include <poll.h>
34 #include <string.h>
35 #include <signal.h>
36 #include <sys/types.h>
37 #include <sys/stat.h>
38 #include <sys/stropts.h>
39 #include <sys/resource.h>
40 #include <sys/termios.h>
41 #include <pwd.h>
42 #include <grp.h>
43 #include <unistd.h>
44 #include <ulimit.h>
45 
46 #include "sac.h"
47 #include "ttymon.h"
48 #include "tmstruct.h"
49 #include "tmextern.h"
50 
51 static	int	Initialized;
52 
53 extern	int	Retry;
54 extern	struct	pollfd	*Pollp;
55 static	void	initialize();
56 static	void	open_all();
57 static	int	set_poll();
58 static	int	check_spawnlimit();
59 static	int	mod_ttydefs();
60 
61 void	open_device();
62 void	set_softcar();
63 
64 extern	int	check_session();
65 extern	void	sigalarm();
66 extern	void	revokedevaccess(char *, uid_t, gid_t, mode_t);
67 /* can't include libdevinfo.h */
68 extern int di_devperm_logout(const char *);
69 
70 /*
71  * 	ttymon	- a port monitor under SAC
72  *		- monitor ports, set terminal modes, baud rate
73  *		  and line discipline for the port
74  *		- invoke service on port if connection request received
75  *		- Usage: ttymon
76  *			 ttymon -g [options]
77  *			 Valid options are
78  *			 -h
79  *			 -d device
80  *			 -l ttylabel
81  *			 -t timeout
82  *			 -m modules
83  *			 -p prompt
84  *
85  *		- ttymon without args is invoked by SAC
86  *		- ttymon -g is invoked by process that needs to
87  *		  have login service on the fly
88  */
89 
90 int
91 main(int argc, char *argv[])
92 {
93 	int	nfds;
94 	extern	char	*lastname();
95 
96 	/*
97 	 * Only the superuser should execute this command.
98 	 */
99 	if (getuid() != 0)
100 		return (1);
101 
102 	/* remember original signal mask and dispositions */
103 	(void) sigprocmask(SIG_SETMASK, NULL, &Origmask);
104 	(void) sigaction(SIGINT, NULL, &Sigint);
105 	(void) sigaction(SIGALRM, NULL, &Sigalrm);
106 	(void) sigaction(SIGPOLL, NULL, &Sigpoll);
107 	(void) sigaction(SIGQUIT, NULL, &Sigquit);
108 	(void) sigaction(SIGCLD, NULL, &Sigcld);
109 	(void) sigaction(SIGTERM, NULL, &Sigterm);
110 #ifdef	DEBUG
111 	(void) sigaction(SIGUSR1, NULL, &Sigusr1);
112 	(void) sigaction(SIGUSR2, NULL, &Sigusr2);
113 #endif
114 
115 	/*
116 	 * SIGQUIT needs to be ignored. Otherwise, hitting ^\ from
117 	 * console kills ttymon.
118 	 */
119 	(void) signal(SIGQUIT, SIG_IGN);
120 
121 	if ((argc > 1) || (strcmp(lastname(argv[0]), "getty") == 0)) {
122 		ttymon_express(argc, argv);
123 		return (1);	/*NOTREACHED*/
124 	}
125 
126 	initialize();
127 
128 	for (;;) {
129 		nfds = set_poll(Pollp);
130 		if (!Reread_flag) {
131 			if (nfds > 0)
132 				do_poll(Pollp, nfds);
133 			else
134 				(void) pause();
135 		}
136 		/*
137 		 * READDB messages may arrive during poll or pause.
138 		 * So the flag needs to be checked again.
139 		 */
140 		if (Reread_flag) {
141 			Reread_flag = FALSE;
142 			re_read();
143 		}
144 		while (Retry) {
145 			Retry = FALSE;
146 			open_all();
147 		}
148 	}
149 }
150 
151 static	void
152 initialize()
153 {
154 	struct	pmtab	*tp;
155 	register struct passwd *pwdp;
156 	register struct	group	*gp;
157 	struct	rlimit rlimit;
158 	extern	struct	rlimit	Rlimit;
159 	extern	 uid_t	Uucp_uid;
160 	extern	 gid_t	Tty_gid;
161 
162 #ifdef 	DEBUG
163 	extern	opendebug();
164 #endif
165 	Initialized = FALSE;
166 	/*
167 	 * get_environ() must be called first,
168 	 * otherwise we don't know where the log file is
169 	 */
170 	get_environ();
171 	openttymonlog();
172 	openpid();
173 	openpipes();
174 	setup_PCpipe();
175 
176 	log("PMTAG: %s", Tag);
177 	log("Starting state: %s",
178 	    (State == PM_ENABLED) ? "enabled" : "disabled");
179 
180 #ifdef 	DEBUG
181 	opendebug(FALSE);
182 	debug("***** ttymon in initialize *****");
183 	log("debug mode is \t on");
184 #endif
185 
186 	catch_signals();
187 
188 	/* register to receive SIGPOLL when data comes to pmpipe */
189 	if (ioctl(Pfd, I_SETSIG, S_INPUT) < 0)
190 		fatal("I_SETSIG on pmpipe failed: %s", strerror(errno));
191 
192 	sacpoll(); /* this is needed because there may be data already */
193 
194 	Maxfiles = (int)ulimit(4, 0L);	/* get max number of open files */
195 	if (Maxfiles < 0)
196 		fatal("ulimit(4,0L) failed: %s", strerror(errno));
197 
198 	if (getrlimit(RLIMIT_NOFILE, &Rlimit) == -1)
199 		fatal("getrlimit failed: %s", strerror(errno));
200 
201 	rlimit.rlim_cur = rlimit.rlim_max = Rlimit.rlim_max;
202 	if (setrlimit(RLIMIT_NOFILE, &rlimit) == -1)
203 		fatal("setrlimit failed: %s", strerror(errno));
204 
205 	(void) enable_extended_FILE_stdio(-1, -1);
206 
207 	Maxfiles = rlimit.rlim_cur;
208 	Maxfds = Maxfiles - FILE_RESERVED;
209 
210 	log("max open files = %d", Maxfiles);
211 	log("max ports ttymon can monitor = %d", Maxfds);
212 
213 	read_pmtab();
214 
215 	/*
216 	 * setup poll array
217 	 * 	- we allocate 10 extra pollfd so that
218 	 *	  we do not have to re-malloc when there is
219 	 *	  minor fluctuation in Nentries
220 	 */
221 	Npollfd = Nentries + 10;
222 	if (Npollfd > Maxfds)
223 		Npollfd = Maxfds;
224 	if ((Pollp = (struct pollfd *)
225 	    malloc((unsigned)(Npollfd * sizeof (struct pollfd))))
226 	    == (struct pollfd *)NULL)
227 		fatal("malloc for Pollp failed");
228 
229 	(void) mod_ttydefs();	/* just to initialize Mtime */
230 	if (check_version(TTYDEFS_VERS, TTYDEFS) != 0)
231 		fatal("check /etc/ttydefs version failed");
232 
233 	read_ttydefs(NULL, FALSE);
234 
235 	/* initialize global variables, Uucp_uid & Tty_gid */
236 	if ((pwdp = getpwnam(UUCP)) != NULL)
237 		Uucp_uid = pwdp->pw_uid;
238 	if ((gp = getgrnam(TTY)) == NULL)
239 		log("no group entry for <tty>, default is used");
240 	else
241 		Tty_gid = gp->gr_gid;
242 	endgrent();
243 	endpwent();
244 #ifdef	DEBUG
245 	debug("Uucp_uid = %u, Tty_gid = %u", Uucp_uid, Tty_gid);
246 #endif
247 
248 	log("Initialization Completed");
249 
250 	/* open the devices ttymon monitors */
251 	Retry = TRUE;
252 	while (Retry) {
253 		Retry = FALSE;
254 		for (tp = PMtab; tp; tp = tp->p_next) {
255 			if ((tp->p_status > 0) && (tp->p_fd == 0) &&
256 			    (tp->p_pid == 0) && !(tp->p_ttyflags & I_FLAG) &&
257 			    (!((State == PM_DISABLED) &&
258 			    ((tp->p_dmsg == NULL)||(*(tp->p_dmsg) == '\0'))))) {
259 				open_device(tp);
260 				if (tp->p_fd > 0)
261 					got_carrier(tp);
262 			}
263 		}
264 	}
265 	Initialized = TRUE;
266 }
267 
268 static	void	free_defs();
269 
270 /*
271  *	open_all - open devices in pmtab if the entry is
272  *	         - valid, fd = 0, and pid = 0
273  */
274 static void
275 open_all()
276 {
277 	struct	pmtab	*tp;
278 	int	check_modtime;
279 	sigset_t cset;
280 	sigset_t tset;
281 
282 #ifdef	DEBUG
283 	debug("in open_all");
284 #endif
285 	check_modtime = TRUE;
286 
287 	for (tp = PMtab; tp; tp = tp->p_next) {
288 		if ((tp->p_status > 0) && (tp->p_fd == 0) &&
289 		    (tp->p_pid == 0) &&
290 		    !(tp->p_ttyflags & I_FLAG) && (!((State == PM_DISABLED) &&
291 		    ((tp->p_dmsg == NULL)||(*(tp->p_dmsg) == '\0'))))) {
292 			/*
293 			 * if we have not check modification time and
294 			 * /etc/ttydefs was modified, need to re-read it
295 			 */
296 			if (check_modtime && mod_ttydefs()) {
297 				check_modtime = FALSE;
298 				(void) sigprocmask(SIG_SETMASK, NULL, &cset);
299 				tset = cset;
300 				(void) sigaddset(&tset, SIGCLD);
301 				(void) sigprocmask(SIG_SETMASK, &tset, NULL);
302 				free_defs();
303 #ifdef	DEBUG
304 				debug("/etc/ttydefs is modified, re-read it");
305 #endif
306 				read_ttydefs(NULL, FALSE);
307 				(void) sigprocmask(SIG_SETMASK, &cset, NULL);
308 			}
309 			open_device(tp);
310 			if (tp->p_fd > 0)
311 				got_carrier(tp);
312 		} else if (((tp->p_status == LOCKED) ||
313 		    (tp->p_status == SESSION) ||
314 		    (tp->p_status == UNACCESS)) &&
315 		    (tp->p_fd > 0) &&
316 		    (!((State == PM_DISABLED) &&
317 		    ((tp->p_dmsg == NULL)||(*(tp->p_dmsg) == '\0'))))) {
318 			if (check_modtime && mod_ttydefs()) {
319 				check_modtime = FALSE;
320 				(void) sigprocmask(SIG_SETMASK, NULL, &cset);
321 				tset = cset;
322 				(void) sigaddset(&tset, SIGCLD);
323 				(void) sigprocmask(SIG_SETMASK, &tset, NULL);
324 				free_defs();
325 #ifdef	DEBUG
326 				debug("/etc/ttydefs is modified, re-read it");
327 #endif
328 				read_ttydefs(NULL, FALSE);
329 				(void) sigprocmask(SIG_SETMASK, &cset, NULL);
330 			}
331 			tp->p_status = VALID;
332 			open_device(tp);
333 			if (tp->p_fd > 0)
334 				got_carrier(tp);
335 		}
336 	}
337 }
338 
339 void
340 set_softcar(pmptr)
341 struct	pmtab	*pmptr;
342 {
343 
344 	int fd, val = 0;
345 
346 #ifdef	DEBUG
347 	debug("in set_softcar");
348 #endif
349 	/*
350 	 * If soft carrier is not set one way or
351 	 * the other, leave it alone.
352 	 */
353 	if (*pmptr->p_softcar == '\0')
354 		return;
355 
356 	if (*pmptr->p_softcar == 'y')
357 		val = 1;
358 
359 	if ((fd = open(pmptr->p_device, O_RDONLY|O_NONBLOCK|O_NOCTTY)) < 0) {
360 		log("open (%s) failed: %s", pmptr->p_device, strerror(errno));
361 		return;
362 	}
363 
364 	if (ioctl(fd, TIOCSSOFTCAR, &val) < 0)
365 		log("set soft-carrier (%s) failed: %s", pmptr->p_device,
366 		    strerror(errno));
367 
368 	close(fd);
369 }
370 
371 
372 /*
373  *	open_device(pmptr)	- open the device
374  *				- check device lock
375  *				- change owner of device
376  *				- push line disciplines
377  *				- set termio
378  */
379 
380 void
381 open_device(pmptr)
382 struct	pmtab	*pmptr;
383 {
384 	int	fd, tmpfd;
385 	struct	sigaction	sigact;
386 
387 #ifdef	DEBUG
388 	debug("in open_device");
389 #endif
390 
391 	if (pmptr->p_status == GETTY) {
392 		revokedevaccess(pmptr->p_device, 0, 0, 0);
393 
394 		if ((fd = open(pmptr->p_device, O_RDWR)) == -1)
395 			fatal("open (%s) failed: %s", pmptr->p_device,
396 			    strerror(errno));
397 
398 	} else {
399 		if (check_spawnlimit(pmptr) == -1) {
400 			pmptr->p_status = NOTVALID;
401 			log("service <%s> is respawning too rapidly",
402 			    pmptr->p_tag);
403 			return;
404 		}
405 		if (pmptr->p_fd > 0) { /* file already open */
406 			fd = pmptr->p_fd;
407 			pmptr->p_fd = 0;
408 		} else if ((fd = open(pmptr->p_device, O_RDWR|O_NONBLOCK))
409 		    == -1) {
410 			log("open (%s) failed: %s", pmptr->p_device,
411 			    strerror(errno));
412 			if ((errno ==  ENODEV) || (errno == EBUSY)) {
413 				pmptr->p_status = UNACCESS;
414 				Nlocked++;
415 				if (Nlocked == 1) {
416 				    sigact.sa_flags = 0;
417 				    sigact.sa_handler = sigalarm;
418 				    (void) sigemptyset(&sigact.sa_mask);
419 				    (void) sigaction(SIGALRM, &sigact, NULL);
420 				    (void) alarm(ALARMTIME);
421 				}
422 			} else
423 				Retry = TRUE;
424 			return;
425 		}
426 		/* set close-on-exec flag */
427 		if (fcntl(fd, F_SETFD, 1) == -1)
428 			fatal("F_SETFD fcntl failed: %s", strerror(errno));
429 
430 		if (tm_checklock(fd) != 0) {
431 			pmptr->p_status = LOCKED;
432 			(void) close(fd);
433 			Nlocked++;
434 			if (Nlocked == 1) {
435 				sigact.sa_flags = 0;
436 				sigact.sa_handler = sigalarm;
437 				(void) sigemptyset(&sigact.sa_mask);
438 				(void) sigaction(SIGALRM, &sigact, NULL);
439 				(void) alarm(ALARMTIME);
440 			}
441 			return;
442 		}
443 		if (check_session(fd) != 0) {
444 			if ((Initialized) && (pmptr->p_inservice != SESSION)) {
445 				log("Warning -- active session exists on <%s>",
446 				    pmptr->p_device);
447 			} else {
448 				/*
449 				 * this may happen if a service is running
450 				 * and ttymon dies and is restarted,
451 				 * or another process is running on the
452 				 * port.
453 				 */
454 				pmptr->p_status = SESSION;
455 				pmptr->p_inservice = 0;
456 				(void) close(fd);
457 				Nlocked++;
458 				if (Nlocked == 1) {
459 					sigact.sa_flags = 0;
460 					sigact.sa_handler = sigalarm;
461 					(void) sigemptyset(&sigact.sa_mask);
462 					(void) sigaction(SIGALRM, &sigact,
463 					    NULL);
464 					(void) alarm(ALARMTIME);
465 				}
466 				return;
467 			}
468 		}
469 		pmptr->p_inservice = 0;
470 	}
471 
472 	if (pmptr->p_ttyflags & H_FLAG) {
473 		/* drop DTR */
474 		(void) hang_up_line(fd);
475 		/*
476 		 * After hang_up_line, the stream is in STRHUP state.
477 		 * We need to do another open to reinitialize streams
478 		 * then we can close one fd
479 		 */
480 		if ((tmpfd = open(pmptr->p_device, O_RDWR|O_NONBLOCK)) == -1) {
481 			log("open (%s) failed: %s", pmptr->p_device,
482 			    strerror(errno));
483 			Retry = TRUE;
484 			(void) close(fd);
485 			return;
486 		}
487 		(void) close(tmpfd);
488 	}
489 
490 #ifdef DEBUG
491 	debug("open_device (%s), fd = %d", pmptr->p_device, fd);
492 #endif
493 
494 	/* Change ownership of the tty line to root/uucp and */
495 	/* set protections to only allow root/uucp to read the line. */
496 
497 	if (pmptr->p_ttyflags & (B_FLAG|C_FLAG))
498 		(void) fchown(fd, Uucp_uid, Tty_gid);
499 	else
500 		(void) fchown(fd, ROOTUID, Tty_gid);
501 	(void) fchmod(fd, 0620);
502 
503 	if ((pmptr->p_modules != NULL)&&(*(pmptr->p_modules) != '\0')) {
504 		if (push_linedisc(fd, pmptr->p_modules, pmptr->p_device)
505 		    == -1) {
506 			Retry = TRUE;
507 			(void) close(fd);
508 			return;
509 		}
510 	}
511 
512 	if (initial_termio(fd, pmptr) == -1)  {
513 		Retry = TRUE;
514 		(void) close(fd);
515 		return;
516 	}
517 
518 	di_devperm_logout((const char *)pmptr->p_device);
519 	pmptr->p_fd = fd;
520 }
521 
522 /*
523  *	set_poll(fdp)	- put all fd's in a pollfd array
524  *			- set poll event to POLLIN and POLLMSG
525  *			- return number of fd to be polled
526  */
527 
528 static	int
529 set_poll(fdp)
530 struct pollfd *fdp;
531 {
532 	struct	pmtab	*tp;
533 	int 	nfd = 0;
534 
535 	for (tp = PMtab; tp; tp = tp->p_next) {
536 		if (tp->p_fd > 0)  {
537 			fdp->fd = tp->p_fd;
538 			fdp->events = POLLIN;
539 			fdp++;
540 			nfd++;
541 		}
542 	}
543 	return (nfd);
544 }
545 
546 /*
547  *	check_spawnlimit	- return 0 if spawnlimit is not reached
548  *				- otherwise return -1
549  */
550 static	int
551 check_spawnlimit(pmptr)
552 struct	pmtab	*pmptr;
553 {
554 	time_t	now;
555 
556 	(void) time(&now);
557 	if (pmptr->p_time == 0L)
558 		pmptr->p_time = now;
559 	if (pmptr->p_respawn >= SPAWN_LIMIT) {
560 		if ((now - pmptr->p_time) < SPAWN_INTERVAL) {
561 			pmptr->p_time = now;
562 			pmptr->p_respawn = 0;
563 			return (-1);
564 		}
565 		pmptr->p_time = now;
566 		pmptr->p_respawn = 0;
567 	}
568 	pmptr->p_respawn++;
569 	return (0);
570 }
571 
572 /*
573  * mod_ttydefs	- to check if /etc/ttydefs has been modified
574  *		- return TRUE if file modified
575  *		- otherwise, return FALSE
576  */
577 static	int
578 mod_ttydefs()
579 {
580 	struct	stat	statbuf;
581 	extern	long	Mtime;
582 	if (stat(TTYDEFS, &statbuf) == -1) {
583 		/* if stat failed, don't bother reread ttydefs */
584 		return (FALSE);
585 	}
586 	if ((long)statbuf.st_mtime != Mtime) {
587 		Mtime = (long)statbuf.st_mtime;
588 		return (TRUE);
589 	}
590 	return (FALSE);
591 }
592 
593 /*
594  *	free_defs - free the Gdef table
595  */
596 static	void
597 free_defs()
598 {
599 	int	i;
600 	struct	Gdef	*tp;
601 	tp = &Gdef[0];
602 	for (i = 0; i < Ndefs; i++, tp++) {
603 		free(tp->g_id);
604 		free(tp->g_iflags);
605 		free(tp->g_fflags);
606 		free(tp->g_nextid);
607 		tp->g_id = NULL;
608 		tp->g_iflags = NULL;
609 		tp->g_fflags = NULL;
610 		tp->g_nextid = NULL;
611 	}
612 	Ndefs = 0;
613 }
614 
615 /*
616  * struct Gdef *get_speed(ttylabel)
617  *	- search "/etc/ttydefs" for speed and term. specification
618  *	  using "ttylabel". If "ttylabel" is NULL, default
619  *	  to DEFAULT
620  * arg:	  ttylabel - label/id of speed settings.
621  */
622 
623 struct Gdef *
624 get_speed(char *ttylabel)
625 {
626 	register struct Gdef *sp;
627 	extern   struct Gdef DEFAULT;
628 
629 	if ((ttylabel != NULL) && (*ttylabel != '\0')) {
630 		if ((sp = find_def(ttylabel)) == NULL) {
631 			log("unable to find <%s> in \"%s\"", ttylabel, TTYDEFS);
632 			sp = &DEFAULT; /* use default */
633 		}
634 	} else sp = &DEFAULT; /* use default */
635 	return (sp);
636 }
637 
638 /*
639  * setup_PCpipe()	- setup the pipe between Parent and Children
640  *			- the pipe is used for a tmchild to send its
641  *			  pid to inform ttymon that it is about to
642  *			  invoke service
643  *			- the pipe also serves as a mean for tmchild
644  *			  to detect failure of ttymon
645  */
646 void
647 setup_PCpipe()
648 {
649 	int	flag = 0;
650 
651 	if (pipe(PCpipe) == -1)
652 		fatal("pipe() failed: %s", strerror(errno));
653 
654 	/* set close-on-exec flag */
655 	if (fcntl(PCpipe[0], F_SETFD, 1) == -1)
656 		fatal("F_SETFD fcntl failed: %s", strerror(errno));
657 
658 	if (fcntl(PCpipe[1], F_SETFD, 1) == -1)
659 		fatal("F_SETFD fcntl failed: %s", strerror(errno));
660 
661 	/* set O_NONBLOCK flag */
662 	if (fcntl(PCpipe[0], F_GETFL, flag) == -1)
663 		fatal("F_GETFL failed: %s", strerror(errno));
664 
665 	flag |= O_NONBLOCK;
666 	if (fcntl(PCpipe[0], F_SETFL, flag) == -1)
667 		fatal("F_SETFL failed: %s", strerror(errno));
668 
669 	/* set message discard mode */
670 	if (ioctl(PCpipe[0], I_SRDOPT, RMSGD) == -1)
671 		fatal("I_SRDOPT RMSGD failed: %s", strerror(errno));
672 
673 	/* register to receive SIGPOLL when data come */
674 	if (ioctl(PCpipe[0], I_SETSIG, S_INPUT) == -1)
675 		fatal("I_SETSIG S_INPUT failed: %s", strerror(errno));
676 
677 #ifdef 	DEBUG
678 	log("PCpipe[0]\t = %d", PCpipe[0]);
679 	log("PCpipe[1]\t = %d", PCpipe[1]);
680 #endif
681 }
682