xref: /illumos-gate/usr/src/cmd/ttymon/ttymon.c (revision 5b0d53307d70a828ad7aef4dc6d8a3ad7d5c231b)
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 #include <libdevinfo.h>
46 
47 #include "sac.h"
48 #include "ttymon.h"
49 #include "tmstruct.h"
50 #include "tmextern.h"
51 
52 static	int	Initialized;
53 
54 static	void	initialize(void);
55 static	void	open_all(void);
56 static	int	set_poll(struct pollfd *);
57 static	int	check_spawnlimit(struct pmtab *);
58 static	int	mod_ttydefs(void);
59 
60 void	open_device(struct pmtab *);
61 void	set_softcar(struct pmtab *);
62 
63 /*
64  *	ttymon	- a port monitor under SAC
65  *		- monitor ports, set terminal modes, baud rate
66  *		  and line discipline for the port
67  *		- invoke service on port if connection request received
68  *		- Usage: ttymon
69  *			 ttymon -g [options]
70  *			 Valid options are
71  *			 -h
72  *			 -d device
73  *			 -l ttylabel
74  *			 -t timeout
75  *			 -m modules
76  *			 -p prompt
77  *
78  *		- ttymon without args is invoked by SAC
79  *		- ttymon -g is invoked by process that needs to
80  *		  have login service on the fly
81  */
82 
83 int
84 main(int argc, char *argv[])
85 {
86 	int	nfds;
87 
88 	/*
89 	 * Only the superuser should execute this command.
90 	 */
91 	if (getuid() != 0)
92 		return (1);
93 
94 	/* remember original signal mask and dispositions */
95 	(void) sigprocmask(SIG_SETMASK, NULL, &Origmask);
96 	(void) sigaction(SIGINT, NULL, &Sigint);
97 	(void) sigaction(SIGALRM, NULL, &Sigalrm);
98 	(void) sigaction(SIGPOLL, NULL, &Sigpoll);
99 	(void) sigaction(SIGQUIT, NULL, &Sigquit);
100 	(void) sigaction(SIGCLD, NULL, &Sigcld);
101 	(void) sigaction(SIGTERM, NULL, &Sigterm);
102 #ifdef	DEBUG
103 	(void) sigaction(SIGUSR1, NULL, &Sigusr1);
104 	(void) sigaction(SIGUSR2, NULL, &Sigusr2);
105 #endif
106 
107 	/*
108 	 * SIGQUIT needs to be ignored. Otherwise, hitting ^\ from
109 	 * console kills ttymon.
110 	 */
111 	(void) signal(SIGQUIT, SIG_IGN);
112 
113 	if ((argc > 1) || (strcmp(lastname(argv[0]), "getty") == 0)) {
114 		ttymon_express(argc, argv);
115 		return (1);	/*NOTREACHED*/
116 	}
117 
118 	initialize();
119 
120 	for (;;) {
121 		nfds = set_poll(Pollp);
122 		if (!Reread_flag) {
123 			if (nfds > 0)
124 				do_poll(Pollp, nfds);
125 			else
126 				(void) pause();
127 		}
128 		/*
129 		 * READDB messages may arrive during poll or pause.
130 		 * So the flag needs to be checked again.
131 		 */
132 		if (Reread_flag) {
133 			Reread_flag = FALSE;
134 			re_read();
135 		}
136 		while (Retry) {
137 			Retry = FALSE;
138 			open_all();
139 		}
140 	}
141 }
142 
143 static	void
144 initialize(void)
145 {
146 	struct	pmtab	*tp;
147 	struct passwd *pwdp;
148 	struct	group	*gp;
149 	struct	rlimit rlimit;
150 
151 	Initialized = FALSE;
152 	/*
153 	 * get_environ() must be called first,
154 	 * otherwise we don't know where the log file is
155 	 */
156 	get_environ();
157 	openttymonlog();
158 	openpid();
159 	openpipes();
160 	setup_PCpipe();
161 
162 	log("PMTAG: %s", Tag);
163 	log("Starting state: %s",
164 	    (State == PM_ENABLED) ? "enabled" : "disabled");
165 
166 #ifdef	DEBUG
167 	opendebug(FALSE);
168 	debug("***** ttymon in initialize *****");
169 	log("debug mode is \t on");
170 #endif
171 
172 	catch_signals();
173 
174 	/* register to receive SIGPOLL when data comes to pmpipe */
175 	if (ioctl(Pfd, I_SETSIG, S_INPUT) < 0)
176 		fatal("I_SETSIG on pmpipe failed: %s", strerror(errno));
177 
178 	sacpoll(); /* this is needed because there may be data already */
179 
180 	Maxfiles = (int)ulimit(4, 0L);	/* get max number of open files */
181 	if (Maxfiles < 0)
182 		fatal("ulimit(4,0L) failed: %s", strerror(errno));
183 
184 	if (getrlimit(RLIMIT_NOFILE, &Rlimit) == -1)
185 		fatal("getrlimit failed: %s", strerror(errno));
186 
187 	rlimit.rlim_cur = rlimit.rlim_max = Rlimit.rlim_max;
188 	if (setrlimit(RLIMIT_NOFILE, &rlimit) == -1)
189 		fatal("setrlimit failed: %s", strerror(errno));
190 
191 	(void) enable_extended_FILE_stdio(-1, -1);
192 
193 	Maxfiles = rlimit.rlim_cur;
194 	Maxfds = Maxfiles - FILE_RESERVED;
195 
196 	log("max open files = %d", Maxfiles);
197 	log("max ports ttymon can monitor = %d", Maxfds);
198 
199 	read_pmtab();
200 
201 	/*
202 	 * setup poll array
203 	 *	- we allocate 10 extra pollfd so that
204 	 *	  we do not have to re-malloc when there is
205 	 *	  minor fluctuation in Nentries
206 	 */
207 	Npollfd = Nentries + 10;
208 	if (Npollfd > Maxfds)
209 		Npollfd = Maxfds;
210 	if ((Pollp = (struct pollfd *)
211 	    malloc((unsigned)(Npollfd * sizeof (struct pollfd))))
212 	    == (struct pollfd *)NULL)
213 		fatal("malloc for Pollp failed");
214 
215 	(void) mod_ttydefs();	/* just to initialize Mtime */
216 	if (check_version(TTYDEFS_VERS, TTYDEFS) != 0)
217 		fatal("check /etc/ttydefs version failed");
218 
219 	read_ttydefs(NULL, FALSE);
220 
221 	/* initialize global variables, Uucp_uid & Tty_gid */
222 	if ((pwdp = getpwnam(UUCP)) != NULL)
223 		Uucp_uid = pwdp->pw_uid;
224 	if ((gp = getgrnam(TTY)) == NULL)
225 		log("no group entry for <tty>, default is used");
226 	else
227 		Tty_gid = gp->gr_gid;
228 	endgrent();
229 	endpwent();
230 #ifdef	DEBUG
231 	debug("Uucp_uid = %u, Tty_gid = %u", Uucp_uid, Tty_gid);
232 #endif
233 
234 	log("Initialization Completed");
235 
236 	/* open the devices ttymon monitors */
237 	Retry = TRUE;
238 	while (Retry) {
239 		Retry = FALSE;
240 		for (tp = PMtab; tp; tp = tp->p_next) {
241 			if ((tp->p_status > 0) && (tp->p_fd == 0) &&
242 			    (tp->p_childpid == 0) &&
243 			    !(tp->p_ttyflags & I_FLAG) &&
244 			    (!((State == PM_DISABLED) &&
245 			    ((tp->p_dmsg == NULL)||(*(tp->p_dmsg) == '\0'))))) {
246 				open_device(tp);
247 				if (tp->p_fd > 0)
248 					got_carrier(tp);
249 			}
250 		}
251 	}
252 	Initialized = TRUE;
253 }
254 
255 static	void	free_defs(void);
256 
257 /*
258  *	open_all - open devices in pmtab if the entry is
259  *	         - valid, fd = 0, and pid = 0
260  */
261 static void
262 open_all(void)
263 {
264 	struct	pmtab	*tp;
265 	int	check_modtime;
266 	sigset_t cset;
267 	sigset_t tset;
268 
269 #ifdef	DEBUG
270 	debug("in open_all");
271 #endif
272 	check_modtime = TRUE;
273 
274 	for (tp = PMtab; tp; tp = tp->p_next) {
275 		if ((tp->p_status > 0) && (tp->p_fd == 0) &&
276 		    (tp->p_childpid == 0) &&
277 		    !(tp->p_ttyflags & I_FLAG) && (!((State == PM_DISABLED) &&
278 		    ((tp->p_dmsg == NULL)||(*(tp->p_dmsg) == '\0'))))) {
279 			/*
280 			 * if we have not check modification time and
281 			 * /etc/ttydefs was modified, need to re-read it
282 			 */
283 			if (check_modtime && mod_ttydefs()) {
284 				check_modtime = FALSE;
285 				(void) sigprocmask(SIG_SETMASK, NULL, &cset);
286 				tset = cset;
287 				(void) sigaddset(&tset, SIGCLD);
288 				(void) sigprocmask(SIG_SETMASK, &tset, NULL);
289 				free_defs();
290 #ifdef	DEBUG
291 				debug("/etc/ttydefs is modified, re-read it");
292 #endif
293 				read_ttydefs(NULL, FALSE);
294 				(void) sigprocmask(SIG_SETMASK, &cset, NULL);
295 			}
296 			open_device(tp);
297 			if (tp->p_fd > 0)
298 				got_carrier(tp);
299 		} else if (((tp->p_status == LOCKED) ||
300 		    (tp->p_status == SESSION) ||
301 		    (tp->p_status == UNACCESS)) &&
302 		    (tp->p_fd > 0) &&
303 		    (!((State == PM_DISABLED) &&
304 		    ((tp->p_dmsg == NULL)||(*(tp->p_dmsg) == '\0'))))) {
305 			if (check_modtime && mod_ttydefs()) {
306 				check_modtime = FALSE;
307 				(void) sigprocmask(SIG_SETMASK, NULL, &cset);
308 				tset = cset;
309 				(void) sigaddset(&tset, SIGCLD);
310 				(void) sigprocmask(SIG_SETMASK, &tset, NULL);
311 				free_defs();
312 #ifdef	DEBUG
313 				debug("/etc/ttydefs is modified, re-read it");
314 #endif
315 				read_ttydefs(NULL, FALSE);
316 				(void) sigprocmask(SIG_SETMASK, &cset, NULL);
317 			}
318 			tp->p_status = VALID;
319 			open_device(tp);
320 			if (tp->p_fd > 0)
321 				got_carrier(tp);
322 		}
323 	}
324 }
325 
326 void
327 set_softcar(struct pmtab *pmptr)
328 {
329 
330 	int fd, val = 0;
331 
332 #ifdef	DEBUG
333 	debug("in set_softcar");
334 #endif
335 	/*
336 	 * If soft carrier is not set one way or
337 	 * the other, leave it alone.
338 	 */
339 	if (*pmptr->p_softcar == '\0')
340 		return;
341 
342 	if (*pmptr->p_softcar == 'y')
343 		val = 1;
344 
345 	if ((fd = open(pmptr->p_device, O_RDONLY|O_NONBLOCK|O_NOCTTY)) < 0) {
346 		log("open (%s) failed: %s", pmptr->p_device, strerror(errno));
347 		return;
348 	}
349 
350 	if (ioctl(fd, TIOCSSOFTCAR, &val) < 0)
351 		log("set soft-carrier (%s) failed: %s", pmptr->p_device,
352 		    strerror(errno));
353 
354 	(void) close(fd);
355 }
356 
357 
358 /*
359  *	open_device(pmptr)	- open the device
360  *				- check device lock
361  *				- change owner of device
362  *				- push line disciplines
363  *				- set termio
364  */
365 
366 void
367 open_device(struct pmtab *pmptr)
368 {
369 	int	fd, tmpfd;
370 	struct	sigaction	sigact;
371 
372 #ifdef	DEBUG
373 	debug("in open_device");
374 #endif
375 
376 	if (pmptr->p_status == GETTY) {
377 		revokedevaccess(pmptr->p_device, 0, 0, 0);
378 
379 		if ((fd = open(pmptr->p_device, O_RDWR)) == -1)
380 			fatal("open (%s) failed: %s", pmptr->p_device,
381 			    strerror(errno));
382 
383 	} else {
384 		if (check_spawnlimit(pmptr) == -1) {
385 			pmptr->p_status = NOTVALID;
386 			log("service <%s> is respawning too rapidly",
387 			    pmptr->p_tag);
388 			return;
389 		}
390 		if (pmptr->p_fd > 0) { /* file already open */
391 			fd = pmptr->p_fd;
392 			pmptr->p_fd = 0;
393 		} else if ((fd = open(pmptr->p_device, O_RDWR|O_NONBLOCK))
394 		    == -1) {
395 			log("open (%s) failed: %s", pmptr->p_device,
396 			    strerror(errno));
397 			if ((errno ==  ENODEV) || (errno == EBUSY)) {
398 				pmptr->p_status = UNACCESS;
399 				Nlocked++;
400 				if (Nlocked == 1) {
401 					sigact.sa_flags = 0;
402 					sigact.sa_handler = sigalarm;
403 					(void) sigemptyset(&sigact.sa_mask);
404 					(void) sigaction(SIGALRM, &sigact,
405 					    NULL);
406 					(void) alarm(ALARMTIME);
407 				}
408 			} else
409 				Retry = TRUE;
410 			return;
411 		}
412 		/* set close-on-exec flag */
413 		if (fcntl(fd, F_SETFD, 1) == -1)
414 			fatal("F_SETFD fcntl failed: %s", strerror(errno));
415 
416 		if (tm_checklock(fd) != 0) {
417 			pmptr->p_status = LOCKED;
418 			(void) close(fd);
419 			Nlocked++;
420 			if (Nlocked == 1) {
421 				sigact.sa_flags = 0;
422 				sigact.sa_handler = sigalarm;
423 				(void) sigemptyset(&sigact.sa_mask);
424 				(void) sigaction(SIGALRM, &sigact, NULL);
425 				(void) alarm(ALARMTIME);
426 			}
427 			return;
428 		}
429 		if (check_session(fd) != 0) {
430 			if ((Initialized) && (pmptr->p_inservice != SESSION)) {
431 				log("Warning -- active session exists on <%s>",
432 				    pmptr->p_device);
433 			} else {
434 				/*
435 				 * this may happen if a service is running
436 				 * and ttymon dies and is restarted,
437 				 * or another process is running on the
438 				 * port.
439 				 */
440 				pmptr->p_status = SESSION;
441 				pmptr->p_inservice = 0;
442 				(void) close(fd);
443 				Nlocked++;
444 				if (Nlocked == 1) {
445 					sigact.sa_flags = 0;
446 					sigact.sa_handler = sigalarm;
447 					(void) sigemptyset(&sigact.sa_mask);
448 					(void) sigaction(SIGALRM, &sigact,
449 					    NULL);
450 					(void) alarm(ALARMTIME);
451 				}
452 				return;
453 			}
454 		}
455 		pmptr->p_inservice = 0;
456 	}
457 
458 	if (pmptr->p_ttyflags & H_FLAG) {
459 		/* drop DTR */
460 		(void) hang_up_line(fd);
461 		/*
462 		 * After hang_up_line, the stream is in STRHUP state.
463 		 * We need to do another open to reinitialize streams
464 		 * then we can close one fd
465 		 */
466 		if ((tmpfd = open(pmptr->p_device, O_RDWR|O_NONBLOCK)) == -1) {
467 			log("open (%s) failed: %s", pmptr->p_device,
468 			    strerror(errno));
469 			Retry = TRUE;
470 			(void) close(fd);
471 			return;
472 		}
473 		(void) close(tmpfd);
474 	}
475 
476 #ifdef DEBUG
477 	debug("open_device (%s), fd = %d", pmptr->p_device, fd);
478 #endif
479 
480 	/* Change ownership of the tty line to root/uucp and */
481 	/* set protections to only allow root/uucp to read the line. */
482 
483 	if (pmptr->p_ttyflags & (B_FLAG|C_FLAG))
484 		(void) fchown(fd, Uucp_uid, Tty_gid);
485 	else
486 		(void) fchown(fd, ROOTUID, Tty_gid);
487 	(void) fchmod(fd, 0620);
488 
489 	if ((pmptr->p_modules != NULL)&&(*(pmptr->p_modules) != '\0')) {
490 		if (push_linedisc(fd, pmptr->p_modules, pmptr->p_device)
491 		    == -1) {
492 			Retry = TRUE;
493 			(void) close(fd);
494 			return;
495 		}
496 	}
497 
498 	if (initial_termio(fd, pmptr) == -1)  {
499 		Retry = TRUE;
500 		(void) close(fd);
501 		return;
502 	}
503 
504 	(void) di_devperm_logout((const char *)pmptr->p_device);
505 	pmptr->p_fd = fd;
506 }
507 
508 /*
509  *	set_poll(fdp)	- put all fd's in a pollfd array
510  *			- set poll event to POLLIN and POLLMSG
511  *			- return number of fd to be polled
512  */
513 
514 static	int
515 set_poll(struct pollfd *fdp)
516 {
517 	struct	pmtab	*tp;
518 	int	nfd = 0;
519 
520 	for (tp = PMtab; tp; tp = tp->p_next) {
521 		if (tp->p_fd > 0)  {
522 			fdp->fd = tp->p_fd;
523 			fdp->events = POLLIN;
524 			fdp++;
525 			nfd++;
526 		}
527 	}
528 	return (nfd);
529 }
530 
531 /*
532  *	check_spawnlimit	- return 0 if spawnlimit is not reached
533  *				- otherwise return -1
534  */
535 static	int
536 check_spawnlimit(struct pmtab *pmptr)
537 {
538 	time_t	now;
539 
540 	(void) time(&now);
541 	if (pmptr->p_time == 0L)
542 		pmptr->p_time = now;
543 	if (pmptr->p_respawn >= SPAWN_LIMIT) {
544 		if ((now - pmptr->p_time) < SPAWN_INTERVAL) {
545 			pmptr->p_time = now;
546 			pmptr->p_respawn = 0;
547 			return (-1);
548 		}
549 		pmptr->p_time = now;
550 		pmptr->p_respawn = 0;
551 	}
552 	pmptr->p_respawn++;
553 	return (0);
554 }
555 
556 /*
557  * mod_ttydefs	- to check if /etc/ttydefs has been modified
558  *		- return TRUE if file modified
559  *		- otherwise, return FALSE
560  */
561 static	int
562 mod_ttydefs(void)
563 {
564 	struct	stat	statbuf;
565 
566 	if (stat(TTYDEFS, &statbuf) == -1) {
567 		/* if stat failed, don't bother reread ttydefs */
568 		return (FALSE);
569 	}
570 	if ((long)statbuf.st_mtime != Mtime) {
571 		Mtime = (long)statbuf.st_mtime;
572 		return (TRUE);
573 	}
574 	return (FALSE);
575 }
576 
577 /*
578  *	free_defs - free the Gdef table
579  */
580 static	void
581 free_defs(void)
582 {
583 	int	i;
584 	struct	Gdef	*tp;
585 	tp = &Gdef[0];
586 	for (i = 0; i < Ndefs; i++, tp++) {
587 		free(tp->g_id);
588 		free(tp->g_iflags);
589 		free(tp->g_fflags);
590 		free(tp->g_nextid);
591 		tp->g_id = NULL;
592 		tp->g_iflags = NULL;
593 		tp->g_fflags = NULL;
594 		tp->g_nextid = NULL;
595 	}
596 	Ndefs = 0;
597 }
598 
599 /*
600  * struct Gdef *get_speed(ttylabel)
601  *	- search "/etc/ttydefs" for speed and term. specification
602  *	  using "ttylabel". If "ttylabel" is NULL, default
603  *	  to DEFAULT
604  * arg:	  ttylabel - label/id of speed settings.
605  */
606 
607 struct Gdef *
608 get_speed(char *ttylabel)
609 {
610 	struct Gdef *sp;
611 
612 	if ((ttylabel != NULL) && (*ttylabel != '\0')) {
613 		if ((sp = find_def(ttylabel)) == NULL) {
614 			log("unable to find <%s> in \"%s\"", ttylabel, TTYDEFS);
615 			sp = &DEFAULT; /* use default */
616 		}
617 	} else sp = &DEFAULT; /* use default */
618 	return (sp);
619 }
620 
621 /*
622  * setup_PCpipe()	- setup the pipe between Parent and Children
623  *			- the pipe is used for a tmchild to send its
624  *			  pid to inform ttymon that it is about to
625  *			  invoke service
626  *			- the pipe also serves as a mean for tmchild
627  *			  to detect failure of ttymon
628  */
629 void
630 setup_PCpipe(void)
631 {
632 	int	flag = 0;
633 
634 	if (pipe(PCpipe) == -1)
635 		fatal("pipe() failed: %s", strerror(errno));
636 
637 	/* set close-on-exec flag */
638 	if (fcntl(PCpipe[0], F_SETFD, 1) == -1)
639 		fatal("F_SETFD fcntl failed: %s", strerror(errno));
640 
641 	if (fcntl(PCpipe[1], F_SETFD, 1) == -1)
642 		fatal("F_SETFD fcntl failed: %s", strerror(errno));
643 
644 	/* set O_NONBLOCK flag */
645 	if (fcntl(PCpipe[0], F_GETFL, flag) == -1)
646 		fatal("F_GETFL failed: %s", strerror(errno));
647 
648 	flag |= O_NONBLOCK;
649 	if (fcntl(PCpipe[0], F_SETFL, flag) == -1)
650 		fatal("F_SETFL failed: %s", strerror(errno));
651 
652 	/* set message discard mode */
653 	if (ioctl(PCpipe[0], I_SRDOPT, RMSGD) == -1)
654 		fatal("I_SRDOPT RMSGD failed: %s", strerror(errno));
655 
656 	/* register to receive SIGPOLL when data come */
657 	if (ioctl(PCpipe[0], I_SETSIG, S_INPUT) == -1)
658 		fatal("I_SETSIG S_INPUT failed: %s", strerror(errno));
659 
660 #ifdef	DEBUG
661 	log("PCpipe[0]\t = %d", PCpipe[0]);
662 	log("PCpipe[1]\t = %d", PCpipe[1]);
663 #endif
664 }
665