xref: /freebsd/sys/kern/tty.c (revision 41ba7e9b13c4c50e6110d72e5a9eb9b91fe981fd)
1 /*-
2  * Copyright (c) 2008 Ed Schouten <ed@FreeBSD.org>
3  * All rights reserved.
4  *
5  * Portions of this software were developed under sponsorship from Snow
6  * B.V., the Netherlands.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 #include <sys/cdefs.h>
31 __FBSDID("$FreeBSD$");
32 
33 #include "opt_compat.h"
34 
35 #include <sys/param.h>
36 #include <sys/conf.h>
37 #include <sys/cons.h>
38 #include <sys/fcntl.h>
39 #include <sys/file.h>
40 #include <sys/filedesc.h>
41 #include <sys/filio.h>
42 #ifdef COMPAT_43TTY
43 #include <sys/ioctl_compat.h>
44 #endif /* COMPAT_43TTY */
45 #include <sys/kernel.h>
46 #include <sys/limits.h>
47 #include <sys/malloc.h>
48 #include <sys/mount.h>
49 #include <sys/poll.h>
50 #include <sys/priv.h>
51 #include <sys/proc.h>
52 #include <sys/serial.h>
53 #include <sys/signal.h>
54 #include <sys/stat.h>
55 #include <sys/sx.h>
56 #include <sys/sysctl.h>
57 #include <sys/systm.h>
58 #include <sys/tty.h>
59 #include <sys/ttycom.h>
60 #define TTYDEFCHARS
61 #include <sys/ttydefaults.h>
62 #undef TTYDEFCHARS
63 #include <sys/ucred.h>
64 #include <sys/vnode.h>
65 
66 #include <machine/stdarg.h>
67 
68 static MALLOC_DEFINE(M_TTY, "tty", "tty device");
69 
70 static void tty_rel_free(struct tty *tp);
71 
72 static TAILQ_HEAD(, tty) tty_list = TAILQ_HEAD_INITIALIZER(tty_list);
73 static struct sx tty_list_sx;
74 SX_SYSINIT(tty_list, &tty_list_sx, "tty list");
75 static unsigned int tty_list_count = 0;
76 
77 /* Character device of /dev/console. */
78 static struct cdev	*dev_console;
79 static const char	*dev_console_filename;
80 
81 /*
82  * Flags that are supported and stored by this implementation.
83  */
84 #define TTYSUP_IFLAG	(IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK|ISTRIP|\
85 			INLCR|IGNCR|ICRNL|IXON|IXOFF|IXANY|IMAXBEL)
86 #define TTYSUP_OFLAG	(OPOST|ONLCR|TAB3|ONOEOT|OCRNL|ONOCR|ONLRET)
87 #define TTYSUP_LFLAG	(ECHOKE|ECHOE|ECHOK|ECHO|ECHONL|ECHOPRT|\
88 			ECHOCTL|ISIG|ICANON|ALTWERASE|IEXTEN|TOSTOP|\
89 			FLUSHO|NOKERNINFO|NOFLSH)
90 #define TTYSUP_CFLAG	(CIGNORE|CSIZE|CSTOPB|CREAD|PARENB|PARODD|\
91 			HUPCL|CLOCAL|CCTS_OFLOW|CRTS_IFLOW|CDTR_IFLOW|\
92 			CDSR_OFLOW|CCAR_OFLOW)
93 
94 #define	TTY_CALLOUT(tp,d) ((d) != (tp)->t_dev && (d) != dev_console)
95 
96 /*
97  * Set TTY buffer sizes.
98  */
99 
100 #define	TTYBUF_MAX	65536
101 
102 static void
103 tty_watermarks(struct tty *tp)
104 {
105 	size_t bs;
106 
107 	/* Provide an input buffer for 0.2 seconds of data. */
108 	bs = MIN(tp->t_termios.c_ispeed / 5, TTYBUF_MAX);
109 	ttyinq_setsize(&tp->t_inq, tp, bs);
110 
111 	/* Set low watermark at 10% (when 90% is available). */
112 	tp->t_inlow = (ttyinq_getsize(&tp->t_inq) * 9) / 10;
113 
114 	/* Provide an ouput buffer for 0.2 seconds of data. */
115 	bs = MIN(tp->t_termios.c_ospeed / 5, TTYBUF_MAX);
116 	ttyoutq_setsize(&tp->t_outq, tp, bs);
117 
118 	/* Set low watermark at 10% (when 90% is available). */
119 	tp->t_outlow = (ttyoutq_getsize(&tp->t_outq) * 9) / 10;
120 }
121 
122 static int
123 tty_drain(struct tty *tp)
124 {
125 	int error;
126 
127 	if (ttyhook_hashook(tp, getc_inject))
128 		/* buffer is inaccessible */
129 		return (0);
130 
131 	while (ttyoutq_bytesused(&tp->t_outq) > 0) {
132 		ttydevsw_outwakeup(tp);
133 		/* Could be handled synchronously. */
134 		if (ttyoutq_bytesused(&tp->t_outq) == 0)
135 			return (0);
136 
137 		/* Wait for data to be drained. */
138 		error = tty_wait(tp, &tp->t_outwait);
139 		if (error)
140 			return (error);
141 	}
142 
143 	return (0);
144 }
145 
146 /*
147  * Though ttydev_enter() and ttydev_leave() seem to be related, they
148  * don't have to be used together. ttydev_enter() is used by the cdev
149  * operations to prevent an actual operation from being processed when
150  * the TTY has been abandoned. ttydev_leave() is used by ttydev_open()
151  * and ttydev_close() to determine whether per-TTY data should be
152  * deallocated.
153  */
154 
155 static __inline int
156 ttydev_enter(struct tty *tp)
157 {
158 	tty_lock(tp);
159 
160 	if (tty_gone(tp) || !tty_opened(tp)) {
161 		/* Device is already gone. */
162 		tty_unlock(tp);
163 		return (ENXIO);
164 	}
165 
166 	return (0);
167 }
168 
169 static void
170 ttydev_leave(struct tty *tp)
171 {
172 	tty_lock_assert(tp, MA_OWNED);
173 
174 	if (tty_opened(tp) || tp->t_flags & TF_OPENCLOSE) {
175 		/* Device is still opened somewhere. */
176 		tty_unlock(tp);
177 		return;
178 	}
179 
180 	tp->t_flags |= TF_OPENCLOSE;
181 
182 	/* Stop asynchronous I/O. */
183 	funsetown(&tp->t_sigio);
184 
185 	/* Remove console TTY. */
186 	if (constty == tp)
187 		constty_clear();
188 
189 	/* Drain any output. */
190 	MPASS((tp->t_flags & TF_STOPPED) == 0);
191 	if (!tty_gone(tp))
192 		tty_drain(tp);
193 
194 	ttydisc_close(tp);
195 
196 	/* Destroy associated buffers already. */
197 	ttyinq_free(&tp->t_inq);
198 	tp->t_inlow = 0;
199 	ttyoutq_free(&tp->t_outq);
200 	tp->t_outlow = 0;
201 
202 	knlist_clear(&tp->t_inpoll.si_note, 1);
203 	knlist_clear(&tp->t_outpoll.si_note, 1);
204 
205 	if (!tty_gone(tp))
206 		ttydevsw_close(tp);
207 
208 	tp->t_flags &= ~TF_OPENCLOSE;
209 	tty_rel_free(tp);
210 }
211 
212 /*
213  * Operations that are exposed through the character device in /dev.
214  */
215 static int
216 ttydev_open(struct cdev *dev, int oflags, int devtype, struct thread *td)
217 {
218 	struct tty *tp = dev->si_drv1;
219 	int error = 0;
220 
221 	/* Disallow access when the TTY belongs to a different prison. */
222 	if (dev->si_cred != NULL &&
223 	    dev->si_cred->cr_prison != td->td_ucred->cr_prison &&
224 	    priv_check(td, PRIV_TTY_PRISON)) {
225 		return (EPERM);
226 	}
227 
228 	tty_lock(tp);
229 	if (tty_gone(tp)) {
230 		/* Device is already gone. */
231 		tty_unlock(tp);
232 		return (ENXIO);
233 	}
234 	/*
235 	 * Prevent the TTY from being opened when being torn down or
236 	 * built up by unrelated processes.
237 	 */
238 	if (tp->t_flags & TF_OPENCLOSE) {
239 		tty_unlock(tp);
240 		return (EBUSY);
241 	}
242 	tp->t_flags |= TF_OPENCLOSE;
243 
244 	/*
245 	 * Make sure the "tty" and "cua" device cannot be opened at the
246 	 * same time.
247 	 */
248 	if (TTY_CALLOUT(tp, dev)) {
249 		if (tp->t_flags & TF_OPENED_IN) {
250 			error = EBUSY;
251 			goto done;
252 		}
253 	} else {
254 		if (tp->t_flags & TF_OPENED_OUT) {
255 			error = EBUSY;
256 			goto done;
257 		}
258 	}
259 
260 	if (tp->t_flags & TF_EXCLUDE && priv_check(td, PRIV_TTY_EXCLUSIVE)) {
261 		error = EBUSY;
262 		goto done;
263 	}
264 
265 	if (!tty_opened(tp)) {
266 		/* Set proper termios flags. */
267 		if (TTY_CALLOUT(tp, dev)) {
268 			tp->t_termios = tp->t_termios_init_out;
269 		} else {
270 			tp->t_termios = tp->t_termios_init_in;
271 		}
272 		ttydevsw_param(tp, &tp->t_termios);
273 
274 		ttydevsw_modem(tp, SER_DTR|SER_RTS, 0);
275 
276 		error = ttydevsw_open(tp);
277 		if (error != 0)
278 			goto done;
279 
280 		ttydisc_open(tp);
281 		tty_watermarks(tp);
282 	}
283 
284 	/* Wait for Carrier Detect. */
285 	if (!TTY_CALLOUT(tp, dev) && (oflags & O_NONBLOCK) == 0 &&
286 	    (tp->t_termios.c_cflag & CLOCAL) == 0) {
287 		while ((ttydevsw_modem(tp, 0, 0) & SER_DCD) == 0) {
288 			error = tty_wait(tp, &tp->t_dcdwait);
289 			if (error != 0)
290 				goto done;
291 		}
292 	}
293 
294 	if (TTY_CALLOUT(tp, dev)) {
295 		tp->t_flags |= TF_OPENED_OUT;
296 	} else {
297 		tp->t_flags |= TF_OPENED_IN;
298 	}
299 
300 done:	tp->t_flags &= ~TF_OPENCLOSE;
301 	ttydev_leave(tp);
302 
303 	return (error);
304 }
305 
306 static int
307 ttydev_close(struct cdev *dev, int fflag, int devtype, struct thread *td)
308 {
309 	struct tty *tp = dev->si_drv1;
310 
311 	/*
312 	 * Don't actually close the device if it is being used as the
313 	 * console.
314 	 */
315 	if (dev_console_filename != NULL &&
316 	    strcmp(dev_console_filename, tty_devname(tp)) == 0)
317 		return (0);
318 
319 	tty_lock(tp);
320 
321 	/*
322 	 * This can only be called once. The callin and the callout
323 	 * devices cannot be opened at the same time.
324 	 */
325 	MPASS((tp->t_flags & TF_OPENED) != TF_OPENED);
326 	tp->t_flags &= ~(TF_OPENED|TF_EXCLUDE|TF_STOPPED);
327 
328 	/* Properly wake up threads that are stuck - revoke(). */
329 	tp->t_revokecnt++;
330 	tty_wakeup(tp, FREAD|FWRITE);
331 	cv_broadcast(&tp->t_bgwait);
332 
333 	ttydev_leave(tp);
334 
335 	return (0);
336 }
337 
338 static __inline int
339 tty_is_ctty(struct tty *tp, struct proc *p)
340 {
341 	tty_lock_assert(tp, MA_OWNED);
342 
343 	return (p->p_session == tp->t_session && p->p_flag & P_CONTROLT);
344 }
345 
346 static int
347 tty_wait_background(struct tty *tp, struct thread *td, int sig)
348 {
349 	struct proc *p = td->td_proc;
350 	struct pgrp *pg;
351 	int error;
352 
353 	MPASS(sig == SIGTTIN || sig == SIGTTOU);
354 	tty_lock_assert(tp, MA_OWNED);
355 
356 	for (;;) {
357 		PROC_LOCK(p);
358 		/*
359 		 * The process should only sleep, when:
360 		 * - This terminal is the controling terminal
361 		 * - Its process group is not the foreground process
362 		 *   group
363 		 * - The parent process isn't waiting for the child to
364 		 *   exit
365 		 * - the signal to send to the process isn't masked
366 		 */
367 		if (!tty_is_ctty(tp, p) ||
368 		    p->p_pgrp == tp->t_pgrp || p->p_flag & P_PPWAIT ||
369 		    SIGISMEMBER(p->p_sigacts->ps_sigignore, sig) ||
370 		    SIGISMEMBER(td->td_sigmask, sig)) {
371 			/* Allow the action to happen. */
372 			PROC_UNLOCK(p);
373 			return (0);
374 		}
375 
376 		/*
377 		 * Send the signal and sleep until we're the new
378 		 * foreground process group.
379 		 */
380 		pg = p->p_pgrp;
381 		PROC_UNLOCK(p);
382 		if (pg->pg_jobc == 0)
383 			return (EIO);
384 		PGRP_LOCK(pg);
385 		pgsignal(pg, sig, 1);
386 		PGRP_UNLOCK(pg);
387 
388 		error = tty_wait(tp, &tp->t_bgwait);
389 		if (error)
390 			return (error);
391 	}
392 }
393 
394 static int
395 ttydev_read(struct cdev *dev, struct uio *uio, int ioflag)
396 {
397 	struct tty *tp = dev->si_drv1;
398 	int error;
399 
400 	error = ttydev_enter(tp);
401 	if (error)
402 		goto done;
403 
404 	error = tty_wait_background(tp, curthread, SIGTTIN);
405 	if (error) {
406 		tty_unlock(tp);
407 		goto done;
408 	}
409 
410 	error = ttydisc_read(tp, uio, ioflag);
411 	tty_unlock(tp);
412 
413 	/*
414 	 * The read() call should not throw an error when the device is
415 	 * being destroyed. Silently convert it to an EOF.
416 	 */
417 done:	if (error == ENXIO)
418 		error = 0;
419 	return (error);
420 }
421 
422 static int
423 ttydev_write(struct cdev *dev, struct uio *uio, int ioflag)
424 {
425 	struct tty *tp = dev->si_drv1;
426 	int error;
427 
428 	error = ttydev_enter(tp);
429 	if (error)
430 		return (error);
431 
432 	if (tp->t_termios.c_lflag & TOSTOP) {
433 		error = tty_wait_background(tp, curthread, SIGTTOU);
434 		if (error) {
435 			tty_unlock(tp);
436 			return (error);
437 		}
438 	}
439 
440 	error = ttydisc_write(tp, uio, ioflag);
441 	tty_unlock(tp);
442 
443 	return (error);
444 }
445 
446 static int
447 ttydev_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int fflag,
448     struct thread *td)
449 {
450 	struct tty *tp = dev->si_drv1;
451 	int error;
452 
453 	error = ttydev_enter(tp);
454 	if (error)
455 		return (error);
456 
457 	switch (cmd) {
458 	case TIOCCBRK:
459 	case TIOCCONS:
460 	case TIOCDRAIN:
461 	case TIOCEXCL:
462 	case TIOCFLUSH:
463 	case TIOCNXCL:
464 	case TIOCSBRK:
465 	case TIOCSCTTY:
466 	case TIOCSETA:
467 	case TIOCSETAF:
468 	case TIOCSETAW:
469 	case TIOCSPGRP:
470 	case TIOCSTART:
471 	case TIOCSTAT:
472 	case TIOCSTOP:
473 	case TIOCSWINSZ:
474 #if 0
475 	case TIOCSDRAINWAIT:
476 	case TIOCSETD:
477 	case TIOCSTI:
478 #endif
479 #ifdef COMPAT_43TTY
480 	case  TIOCLBIC:
481 	case  TIOCLBIS:
482 	case  TIOCLSET:
483 	case  TIOCSETC:
484 	case OTIOCSETD:
485 	case  TIOCSETN:
486 	case  TIOCSETP:
487 	case  TIOCSLTC:
488 #endif /* COMPAT_43TTY */
489 		/*
490 		 * If the ioctl() causes the TTY to be modified, let it
491 		 * wait in the background.
492 		 */
493 		error = tty_wait_background(tp, curthread, SIGTTOU);
494 		if (error)
495 			goto done;
496 	}
497 
498 	error = tty_ioctl(tp, cmd, data, td);
499 done:	tty_unlock(tp);
500 
501 	return (error);
502 }
503 
504 static int
505 ttydev_poll(struct cdev *dev, int events, struct thread *td)
506 {
507 	struct tty *tp = dev->si_drv1;
508 	int error, revents = 0;
509 
510 	error = ttydev_enter(tp);
511 	if (error) {
512 		/* Don't return the error here, but the event mask. */
513 		return (events &
514 		    (POLLHUP|POLLIN|POLLRDNORM|POLLOUT|POLLWRNORM));
515 	}
516 
517 	if (events & (POLLIN|POLLRDNORM)) {
518 		/* See if we can read something. */
519 		if (ttydisc_read_poll(tp) > 0)
520 			revents |= events & (POLLIN|POLLRDNORM);
521 	}
522 	if (events & (POLLOUT|POLLWRNORM)) {
523 		/* See if we can write something. */
524 		if (ttydisc_write_poll(tp) > 0)
525 			revents |= events & (POLLOUT|POLLWRNORM);
526 	}
527 	if (tp->t_flags & TF_ZOMBIE)
528 		/* Hangup flag on zombie state. */
529 		revents |= events & POLLHUP;
530 
531 	if (revents == 0) {
532 		if (events & (POLLIN|POLLRDNORM))
533 			selrecord(td, &tp->t_inpoll);
534 		if (events & (POLLOUT|POLLWRNORM))
535 			selrecord(td, &tp->t_outpoll);
536 	}
537 
538 	tty_unlock(tp);
539 
540 	return (revents);
541 }
542 
543 static int
544 ttydev_mmap(struct cdev *dev, vm_offset_t offset, vm_paddr_t *paddr, int nprot)
545 {
546 	struct tty *tp = dev->si_drv1;
547 	int error;
548 
549 	/* Handle mmap() through the driver. */
550 
551 	error = ttydev_enter(tp);
552 	if (error)
553 		return (-1);
554 	error = ttydevsw_mmap(tp, offset, paddr, nprot);
555 	tty_unlock(tp);
556 
557 	return (error);
558 }
559 
560 /*
561  * kqueue support.
562  */
563 
564 static void
565 tty_kqops_read_detach(struct knote *kn)
566 {
567 	struct tty *tp = kn->kn_hook;
568 
569 	knlist_remove(&tp->t_inpoll.si_note, kn, 0);
570 }
571 
572 static int
573 tty_kqops_read_event(struct knote *kn, long hint)
574 {
575 	struct tty *tp = kn->kn_hook;
576 
577 	tty_lock_assert(tp, MA_OWNED);
578 
579 	if (tty_gone(tp) || tp->t_flags & TF_ZOMBIE) {
580 		kn->kn_flags |= EV_EOF;
581 		return (1);
582 	} else {
583 		kn->kn_data = ttydisc_read_poll(tp);
584 		return (kn->kn_data > 0);
585 	}
586 }
587 
588 static void
589 tty_kqops_write_detach(struct knote *kn)
590 {
591 	struct tty *tp = kn->kn_hook;
592 
593 	knlist_remove(&tp->t_outpoll.si_note, kn, 0);
594 }
595 
596 static int
597 tty_kqops_write_event(struct knote *kn, long hint)
598 {
599 	struct tty *tp = kn->kn_hook;
600 
601 	tty_lock_assert(tp, MA_OWNED);
602 
603 	if (tty_gone(tp)) {
604 		kn->kn_flags |= EV_EOF;
605 		return (1);
606 	} else {
607 		kn->kn_data = ttydisc_write_poll(tp);
608 		return (kn->kn_data > 0);
609 	}
610 }
611 
612 static struct filterops tty_kqops_read =
613     { 1, NULL, tty_kqops_read_detach, tty_kqops_read_event };
614 static struct filterops tty_kqops_write =
615     { 1, NULL, tty_kqops_write_detach, tty_kqops_write_event };
616 
617 static int
618 ttydev_kqfilter(struct cdev *dev, struct knote *kn)
619 {
620 	struct tty *tp = dev->si_drv1;
621 	int error;
622 
623 	error = ttydev_enter(tp);
624 	if (error)
625 		return (error);
626 
627 	switch (kn->kn_filter) {
628 	case EVFILT_READ:
629 		kn->kn_hook = tp;
630 		kn->kn_fop = &tty_kqops_read;
631 		knlist_add(&tp->t_inpoll.si_note, kn, 1);
632 		break;
633 	case EVFILT_WRITE:
634 		kn->kn_hook = tp;
635 		kn->kn_fop = &tty_kqops_write;
636 		knlist_add(&tp->t_outpoll.si_note, kn, 1);
637 		break;
638 	default:
639 		error = EINVAL;
640 		break;
641 	}
642 
643 	tty_unlock(tp);
644 	return (error);
645 }
646 
647 static struct cdevsw ttydev_cdevsw = {
648 	.d_version	= D_VERSION,
649 	.d_open		= ttydev_open,
650 	.d_close	= ttydev_close,
651 	.d_read		= ttydev_read,
652 	.d_write	= ttydev_write,
653 	.d_ioctl	= ttydev_ioctl,
654 	.d_kqfilter	= ttydev_kqfilter,
655 	.d_poll		= ttydev_poll,
656 	.d_mmap		= ttydev_mmap,
657 	.d_name		= "ttydev",
658 	.d_flags	= D_TTY,
659 };
660 
661 /*
662  * Init/lock-state devices
663  */
664 
665 static int
666 ttyil_open(struct cdev *dev, int oflags, int devtype, struct thread *td)
667 {
668 	struct tty *tp = dev->si_drv1;
669 	int error = 0;
670 
671 	tty_lock(tp);
672 	if (tty_gone(tp))
673 		error = ENODEV;
674 	tty_unlock(tp);
675 
676 	return (error);
677 }
678 
679 static int
680 ttyil_close(struct cdev *dev, int flag, int mode, struct thread *td)
681 {
682 	return (0);
683 }
684 
685 static int
686 ttyil_rdwr(struct cdev *dev, struct uio *uio, int ioflag)
687 {
688 	return (ENODEV);
689 }
690 
691 static int
692 ttyil_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int fflag,
693     struct thread *td)
694 {
695 	struct tty *tp = dev->si_drv1;
696 	int error = 0;
697 
698 	tty_lock(tp);
699 	if (tty_gone(tp)) {
700 		error = ENODEV;
701 		goto done;
702 	}
703 
704 	switch (cmd) {
705 	case TIOCGETA:
706 		/* Obtain terminal flags through tcgetattr(). */
707 		bcopy(dev->si_drv2, data, sizeof(struct termios));
708 		break;
709 	case TIOCSETA:
710 		/* Set terminal flags through tcsetattr(). */
711 		error = priv_check(td, PRIV_TTY_SETA);
712 		if (error)
713 			break;
714 		bcopy(data, dev->si_drv2, sizeof(struct termios));
715 		break;
716 	case TIOCGETD:
717 		*(int *)data = TTYDISC;
718 		break;
719 	case TIOCGWINSZ:
720 		bzero(data, sizeof(struct winsize));
721 		break;
722 	default:
723 		error = ENOTTY;
724 	}
725 
726 done:	tty_unlock(tp);
727 	return (error);
728 }
729 
730 static struct cdevsw ttyil_cdevsw = {
731 	.d_version	= D_VERSION,
732 	.d_open		= ttyil_open,
733 	.d_close	= ttyil_close,
734 	.d_read		= ttyil_rdwr,
735 	.d_write	= ttyil_rdwr,
736 	.d_ioctl	= ttyil_ioctl,
737 	.d_name		= "ttyil",
738 	.d_flags	= D_TTY,
739 };
740 
741 static void
742 tty_init_termios(struct tty *tp)
743 {
744 	struct termios *t = &tp->t_termios_init_in;
745 
746 	t->c_cflag = TTYDEF_CFLAG;
747 	t->c_iflag = TTYDEF_IFLAG;
748 	t->c_lflag = TTYDEF_LFLAG;
749 	t->c_oflag = TTYDEF_OFLAG;
750 	t->c_ispeed = TTYDEF_SPEED;
751 	t->c_ospeed = TTYDEF_SPEED;
752 	bcopy(ttydefchars, &t->c_cc, sizeof ttydefchars);
753 
754 	tp->t_termios_init_out = *t;
755 }
756 
757 void
758 tty_init_console(struct tty *tp, speed_t s)
759 {
760 	struct termios *ti = &tp->t_termios_init_in;
761 	struct termios *to = &tp->t_termios_init_out;
762 
763 	if (s != 0) {
764 		ti->c_ispeed = ti->c_ospeed = s;
765 		to->c_ispeed = to->c_ospeed = s;
766 	}
767 
768 	ti->c_cflag |= CLOCAL;
769 	to->c_cflag |= CLOCAL;
770 }
771 
772 /*
773  * Standard device routine implementations, mostly meant for
774  * pseudo-terminal device drivers. When a driver creates a new terminal
775  * device class, missing routines are patched.
776  */
777 
778 static int
779 ttydevsw_defopen(struct tty *tp)
780 {
781 
782 	return (0);
783 }
784 
785 static void
786 ttydevsw_defclose(struct tty *tp)
787 {
788 }
789 
790 static void
791 ttydevsw_defoutwakeup(struct tty *tp)
792 {
793 
794 	panic("Terminal device has output, while not implemented");
795 }
796 
797 static void
798 ttydevsw_definwakeup(struct tty *tp)
799 {
800 }
801 
802 static int
803 ttydevsw_defioctl(struct tty *tp, u_long cmd, caddr_t data, struct thread *td)
804 {
805 
806 	return (ENOIOCTL);
807 }
808 
809 static int
810 ttydevsw_defparam(struct tty *tp, struct termios *t)
811 {
812 
813 	/* Use a fake baud rate, we're not a real device. */
814 	t->c_ispeed = t->c_ospeed = TTYDEF_SPEED;
815 
816 	return (0);
817 }
818 
819 static int
820 ttydevsw_defmodem(struct tty *tp, int sigon, int sigoff)
821 {
822 
823 	/* Simulate a carrier to make the TTY layer happy. */
824 	return (SER_DCD);
825 }
826 
827 static int
828 ttydevsw_defmmap(struct tty *tp, vm_offset_t offset, vm_paddr_t *paddr,
829     int nprot)
830 {
831 
832 	return (-1);
833 }
834 
835 static void
836 ttydevsw_defpktnotify(struct tty *tp, char event)
837 {
838 }
839 
840 static void
841 ttydevsw_deffree(void *softc)
842 {
843 
844 	panic("Terminal device freed without a free-handler");
845 }
846 
847 /*
848  * TTY allocation and deallocation. TTY devices can be deallocated when
849  * the driver doesn't use it anymore, when the TTY isn't a session's
850  * controlling TTY and when the device node isn't opened through devfs.
851  */
852 
853 struct tty *
854 tty_alloc(struct ttydevsw *tsw, void *sc, struct mtx *mutex)
855 {
856 	struct tty *tp;
857 
858 	/* Make sure the driver defines all routines. */
859 #define PATCH_FUNC(x) do {				\
860 	if (tsw->tsw_ ## x == NULL)			\
861 		tsw->tsw_ ## x = ttydevsw_def ## x;	\
862 } while (0)
863 	PATCH_FUNC(open);
864 	PATCH_FUNC(close);
865 	PATCH_FUNC(outwakeup);
866 	PATCH_FUNC(inwakeup);
867 	PATCH_FUNC(ioctl);
868 	PATCH_FUNC(param);
869 	PATCH_FUNC(modem);
870 	PATCH_FUNC(mmap);
871 	PATCH_FUNC(pktnotify);
872 	PATCH_FUNC(free);
873 #undef PATCH_FUNC
874 
875 	tp = malloc(sizeof(struct tty), M_TTY, M_WAITOK|M_ZERO);
876 	tp->t_devsw = tsw;
877 	tp->t_devswsoftc = sc;
878 	tp->t_flags = tsw->tsw_flags;
879 
880 	tty_init_termios(tp);
881 
882 	cv_init(&tp->t_inwait, "ttyin");
883 	cv_init(&tp->t_outwait, "ttyout");
884 	cv_init(&tp->t_bgwait, "ttybg");
885 	cv_init(&tp->t_dcdwait, "ttydcd");
886 
887 	/* Allow drivers to use a custom mutex to lock the TTY. */
888 	if (mutex != NULL) {
889 		tp->t_mtx = mutex;
890 	} else {
891 		tp->t_mtx = &tp->t_mtxobj;
892 		mtx_init(&tp->t_mtxobj, "ttymtx", NULL, MTX_DEF);
893 	}
894 
895 	knlist_init(&tp->t_inpoll.si_note, tp->t_mtx, NULL, NULL, NULL);
896 	knlist_init(&tp->t_outpoll.si_note, tp->t_mtx, NULL, NULL, NULL);
897 
898 	sx_xlock(&tty_list_sx);
899 	TAILQ_INSERT_TAIL(&tty_list, tp, t_list);
900 	tty_list_count++;
901 	sx_xunlock(&tty_list_sx);
902 
903 	return (tp);
904 }
905 
906 static void
907 tty_dealloc(void *arg)
908 {
909 	struct tty *tp = arg;
910 
911 	sx_xlock(&tty_list_sx);
912 	TAILQ_REMOVE(&tty_list, tp, t_list);
913 	tty_list_count--;
914 	sx_xunlock(&tty_list_sx);
915 
916 	/* Make sure we haven't leaked buffers. */
917 	MPASS(ttyinq_getsize(&tp->t_inq) == 0);
918 	MPASS(ttyoutq_getsize(&tp->t_outq) == 0);
919 
920 	knlist_destroy(&tp->t_inpoll.si_note);
921 	knlist_destroy(&tp->t_outpoll.si_note);
922 
923 	cv_destroy(&tp->t_inwait);
924 	cv_destroy(&tp->t_outwait);
925 	cv_destroy(&tp->t_bgwait);
926 	cv_destroy(&tp->t_dcdwait);
927 
928 	if (tp->t_mtx == &tp->t_mtxobj)
929 		mtx_destroy(&tp->t_mtxobj);
930 	ttydevsw_free(tp);
931 	free(tp, M_TTY);
932 }
933 
934 static void
935 tty_rel_free(struct tty *tp)
936 {
937 	struct cdev *dev;
938 
939 	tty_lock_assert(tp, MA_OWNED);
940 
941 #define	TF_ACTIVITY	(TF_GONE|TF_OPENED|TF_HOOK|TF_OPENCLOSE)
942 	if (tp->t_sessioncnt != 0 || (tp->t_flags & TF_ACTIVITY) != TF_GONE) {
943 		/* TTY is still in use. */
944 		tty_unlock(tp);
945 		return;
946 	}
947 
948 	/* TTY can be deallocated. */
949 	dev = tp->t_dev;
950 	tp->t_dev = NULL;
951 	tty_unlock(tp);
952 
953 	destroy_dev_sched_cb(dev, tty_dealloc, tp);
954 }
955 
956 void
957 tty_rel_pgrp(struct tty *tp, struct pgrp *pg)
958 {
959 	MPASS(tp->t_sessioncnt > 0);
960 	tty_lock_assert(tp, MA_OWNED);
961 
962 	if (tp->t_pgrp == pg)
963 		tp->t_pgrp = NULL;
964 
965 	tty_unlock(tp);
966 }
967 
968 void
969 tty_rel_sess(struct tty *tp, struct session *sess)
970 {
971 	MPASS(tp->t_sessioncnt > 0);
972 
973 	/* Current session has left. */
974 	if (tp->t_session == sess) {
975 		tp->t_session = NULL;
976 		MPASS(tp->t_pgrp == NULL);
977 	}
978 	tp->t_sessioncnt--;
979 	tty_rel_free(tp);
980 }
981 
982 void
983 tty_rel_gone(struct tty *tp)
984 {
985 	MPASS(!tty_gone(tp));
986 
987 	/* Simulate carrier removal. */
988 	ttydisc_modem(tp, 0);
989 
990 	/* Wake up all blocked threads. */
991 	tty_wakeup(tp, FREAD|FWRITE);
992 	cv_broadcast(&tp->t_bgwait);
993 	cv_broadcast(&tp->t_dcdwait);
994 
995 	tp->t_flags |= TF_GONE;
996 	tty_rel_free(tp);
997 }
998 
999 /*
1000  * Exposing information about current TTY's through sysctl
1001  */
1002 
1003 static void
1004 tty_to_xtty(struct tty *tp, struct xtty *xt)
1005 {
1006 	tty_lock_assert(tp, MA_OWNED);
1007 
1008 	xt->xt_size = sizeof(struct xtty);
1009 	xt->xt_insize = ttyinq_getsize(&tp->t_inq);
1010 	xt->xt_incc = ttyinq_bytescanonicalized(&tp->t_inq);
1011 	xt->xt_inlc = ttyinq_bytesline(&tp->t_inq);
1012 	xt->xt_inlow = tp->t_inlow;
1013 	xt->xt_outsize = ttyoutq_getsize(&tp->t_outq);
1014 	xt->xt_outcc = ttyoutq_bytesused(&tp->t_outq);
1015 	xt->xt_outlow = tp->t_outlow;
1016 	xt->xt_column = tp->t_column;
1017 	xt->xt_pgid = tp->t_pgrp ? tp->t_pgrp->pg_id : 0;
1018 	xt->xt_sid = tp->t_session ? tp->t_session->s_sid : 0;
1019 	xt->xt_flags = tp->t_flags;
1020 	xt->xt_dev = tp->t_dev ? dev2udev(tp->t_dev) : NODEV;
1021 }
1022 
1023 static int
1024 sysctl_kern_ttys(SYSCTL_HANDLER_ARGS)
1025 {
1026 	unsigned long lsize;
1027 	struct xtty *xtlist, *xt;
1028 	struct tty *tp;
1029 	int error;
1030 
1031 	sx_slock(&tty_list_sx);
1032 	lsize = tty_list_count * sizeof(struct xtty);
1033 	if (lsize == 0) {
1034 		sx_sunlock(&tty_list_sx);
1035 		return (0);
1036 	}
1037 
1038 	xtlist = xt = malloc(lsize, M_TEMP, M_WAITOK);
1039 
1040 	TAILQ_FOREACH(tp, &tty_list, t_list) {
1041 		tty_lock(tp);
1042 		tty_to_xtty(tp, xt);
1043 		tty_unlock(tp);
1044 		xt++;
1045 	}
1046 	sx_sunlock(&tty_list_sx);
1047 
1048 	error = SYSCTL_OUT(req, xtlist, lsize);
1049 	free(xtlist, M_TEMP);
1050 	return (error);
1051 }
1052 
1053 SYSCTL_PROC(_kern, OID_AUTO, ttys, CTLTYPE_OPAQUE|CTLFLAG_RD|CTLFLAG_MPSAFE,
1054 	0, 0, sysctl_kern_ttys, "S,xtty", "List of TTYs");
1055 
1056 /*
1057  * Device node creation. Device has been set up, now we can expose it to
1058  * the user.
1059  */
1060 
1061 void
1062 tty_makedev(struct tty *tp, struct ucred *cred, const char *fmt, ...)
1063 {
1064 	va_list ap;
1065 	struct cdev *dev;
1066 	const char *prefix = "tty";
1067 	char name[SPECNAMELEN - 3]; /* for "tty" and "cua". */
1068 	uid_t uid;
1069 	gid_t gid;
1070 	mode_t mode;
1071 
1072 	/* Remove "tty" prefix from devices like PTY's. */
1073 	if (tp->t_flags & TF_NOPREFIX)
1074 		prefix = "";
1075 
1076 	va_start(ap, fmt);
1077 	vsnrprintf(name, sizeof name, 32, fmt, ap);
1078 	va_end(ap);
1079 
1080 	if (cred == NULL) {
1081 		/* System device. */
1082 		uid = UID_ROOT;
1083 		gid = GID_WHEEL;
1084 		mode = S_IRUSR|S_IWUSR;
1085 	} else {
1086 		/* User device. */
1087 		uid = cred->cr_ruid;
1088 		gid = GID_TTY;
1089 		mode = S_IRUSR|S_IWUSR|S_IWGRP;
1090 	}
1091 
1092 	/* Master call-in device. */
1093 	dev = make_dev_cred(&ttydev_cdevsw, 0, cred,
1094 	    uid, gid, mode, "%s%s", prefix, name);
1095 	dev->si_drv1 = tp;
1096 	tp->t_dev = dev;
1097 
1098 	/* Slave call-in devices. */
1099 	if (tp->t_flags & TF_INITLOCK) {
1100 		dev = make_dev_cred(&ttyil_cdevsw, 0, cred,
1101 		    uid, gid, mode, "%s%s.init", prefix, name);
1102 		dev_depends(tp->t_dev, dev);
1103 		dev->si_drv1 = tp;
1104 		dev->si_drv2 = &tp->t_termios_init_in;
1105 
1106 		dev = make_dev_cred(&ttyil_cdevsw, 0, cred,
1107 		    uid, gid, mode, "%s%s.lock", prefix, name);
1108 		dev_depends(tp->t_dev, dev);
1109 		dev->si_drv1 = tp;
1110 		dev->si_drv2 = &tp->t_termios_lock_in;
1111 	}
1112 
1113 	/* Call-out devices. */
1114 	if (tp->t_flags & TF_CALLOUT) {
1115 		dev = make_dev_cred(&ttydev_cdevsw, 0, cred,
1116 		    UID_UUCP, GID_DIALER, 0660, "cua%s", name);
1117 		dev_depends(tp->t_dev, dev);
1118 		dev->si_drv1 = tp;
1119 
1120 		/* Slave call-out devices. */
1121 		if (tp->t_flags & TF_INITLOCK) {
1122 			dev = make_dev_cred(&ttyil_cdevsw, 0, cred,
1123 			    UID_UUCP, GID_DIALER, 0660, "cua%s.init", name);
1124 			dev_depends(tp->t_dev, dev);
1125 			dev->si_drv1 = tp;
1126 			dev->si_drv2 = &tp->t_termios_init_out;
1127 
1128 			dev = make_dev_cred(&ttyil_cdevsw, 0, cred,
1129 			    UID_UUCP, GID_DIALER, 0660, "cua%s.lock", name);
1130 			dev_depends(tp->t_dev, dev);
1131 			dev->si_drv1 = tp;
1132 			dev->si_drv2 = &tp->t_termios_lock_out;
1133 		}
1134 	}
1135 }
1136 
1137 /*
1138  * Signalling processes.
1139  */
1140 
1141 void
1142 tty_signal_sessleader(struct tty *tp, int sig)
1143 {
1144 	struct proc *p;
1145 
1146 	tty_lock_assert(tp, MA_OWNED);
1147 	MPASS(sig >= 1 && sig < NSIG);
1148 
1149 	/* Make signals start output again. */
1150 	tp->t_flags &= ~TF_STOPPED;
1151 
1152 	if (tp->t_session != NULL && tp->t_session->s_leader != NULL) {
1153 		p = tp->t_session->s_leader;
1154 		PROC_LOCK(p);
1155 		psignal(p, sig);
1156 		PROC_UNLOCK(p);
1157 	}
1158 }
1159 
1160 void
1161 tty_signal_pgrp(struct tty *tp, int sig)
1162 {
1163 	tty_lock_assert(tp, MA_OWNED);
1164 	MPASS(sig >= 1 && sig < NSIG);
1165 
1166 	/* Make signals start output again. */
1167 	tp->t_flags &= ~TF_STOPPED;
1168 
1169 	if (sig == SIGINFO && !(tp->t_termios.c_lflag & NOKERNINFO))
1170 		tty_info(tp);
1171 	if (tp->t_pgrp != NULL) {
1172 		PGRP_LOCK(tp->t_pgrp);
1173 		pgsignal(tp->t_pgrp, sig, 1);
1174 		PGRP_UNLOCK(tp->t_pgrp);
1175 	}
1176 }
1177 
1178 void
1179 tty_wakeup(struct tty *tp, int flags)
1180 {
1181 	if (tp->t_flags & TF_ASYNC && tp->t_sigio != NULL)
1182 		pgsigio(&tp->t_sigio, SIGIO, (tp->t_session != NULL));
1183 
1184 	if (flags & FWRITE) {
1185 		cv_broadcast(&tp->t_outwait);
1186 		selwakeup(&tp->t_outpoll);
1187 		KNOTE_LOCKED(&tp->t_outpoll.si_note, 0);
1188 	}
1189 	if (flags & FREAD) {
1190 		cv_broadcast(&tp->t_inwait);
1191 		selwakeup(&tp->t_inpoll);
1192 		KNOTE_LOCKED(&tp->t_inpoll.si_note, 0);
1193 	}
1194 }
1195 
1196 int
1197 tty_wait(struct tty *tp, struct cv *cv)
1198 {
1199 	int error;
1200 	int revokecnt = tp->t_revokecnt;
1201 
1202 	tty_lock_assert(tp, MA_OWNED|MA_NOTRECURSED);
1203 	MPASS(!tty_gone(tp));
1204 
1205 	error = cv_wait_sig(cv, tp->t_mtx);
1206 
1207 	/* Restart the system call when we may have been revoked. */
1208 	if (tp->t_revokecnt != revokecnt)
1209 		return (ERESTART);
1210 
1211 	/* Bail out when the device slipped away. */
1212 	if (tty_gone(tp))
1213 		return (ENXIO);
1214 
1215 	return (error);
1216 }
1217 
1218 int
1219 tty_timedwait(struct tty *tp, struct cv *cv, int hz)
1220 {
1221 	int error;
1222 	int revokecnt = tp->t_revokecnt;
1223 
1224 	tty_lock_assert(tp, MA_OWNED|MA_NOTRECURSED);
1225 	MPASS(!tty_gone(tp));
1226 
1227 	error = cv_timedwait_sig(cv, tp->t_mtx, hz);
1228 
1229 	/* Restart the system call when we may have been revoked. */
1230 	if (tp->t_revokecnt != revokecnt)
1231 		return (ERESTART);
1232 
1233 	/* Bail out when the device slipped away. */
1234 	if (tty_gone(tp))
1235 		return (ENXIO);
1236 
1237 	return (error);
1238 }
1239 
1240 void
1241 tty_flush(struct tty *tp, int flags)
1242 {
1243 	if (flags & FWRITE) {
1244 		tp->t_flags &= ~TF_HIWAT_OUT;
1245 		ttyoutq_flush(&tp->t_outq);
1246 		tty_wakeup(tp, FWRITE);
1247 		ttydevsw_pktnotify(tp, TIOCPKT_FLUSHWRITE);
1248 	}
1249 	if (flags & FREAD) {
1250 		tty_hiwat_in_unblock(tp);
1251 		ttyinq_flush(&tp->t_inq);
1252 		ttydevsw_inwakeup(tp);
1253 		ttydevsw_pktnotify(tp, TIOCPKT_FLUSHREAD);
1254 	}
1255 }
1256 
1257 static int
1258 tty_generic_ioctl(struct tty *tp, u_long cmd, void *data, struct thread *td)
1259 {
1260 	int error;
1261 
1262 	switch (cmd) {
1263 	/*
1264 	 * Modem commands.
1265 	 * The SER_* and TIOCM_* flags are the same, but one bit
1266 	 * shifted. I don't know why.
1267 	 */
1268 	case TIOCSDTR:
1269 		ttydevsw_modem(tp, SER_DTR, 0);
1270 		return (0);
1271 	case TIOCCDTR:
1272 		ttydevsw_modem(tp, 0, SER_DTR);
1273 		return (0);
1274 	case TIOCMSET: {
1275 		int bits = *(int *)data;
1276 		ttydevsw_modem(tp,
1277 		    (bits & (TIOCM_DTR | TIOCM_RTS)) >> 1,
1278 		    ((~bits) & (TIOCM_DTR | TIOCM_RTS)) >> 1);
1279 		return (0);
1280 	}
1281 	case TIOCMBIS: {
1282 		int bits = *(int *)data;
1283 		ttydevsw_modem(tp, (bits & (TIOCM_DTR | TIOCM_RTS)) >> 1, 0);
1284 		return (0);
1285 	}
1286 	case TIOCMBIC: {
1287 		int bits = *(int *)data;
1288 		ttydevsw_modem(tp, 0, (bits & (TIOCM_DTR | TIOCM_RTS)) >> 1);
1289 		return (0);
1290 	}
1291 	case TIOCMGET:
1292 		*(int *)data = TIOCM_LE + (ttydevsw_modem(tp, 0, 0) << 1);
1293 		return (0);
1294 
1295 	case FIOASYNC:
1296 		if (*(int *)data)
1297 			tp->t_flags |= TF_ASYNC;
1298 		else
1299 			tp->t_flags &= ~TF_ASYNC;
1300 		return (0);
1301 	case FIONBIO:
1302 		/* This device supports non-blocking operation. */
1303 		return (0);
1304 	case FIONREAD:
1305 		*(int *)data = ttyinq_bytescanonicalized(&tp->t_inq);
1306 		return (0);
1307 	case FIOSETOWN:
1308 		if (tp->t_session != NULL && !tty_is_ctty(tp, td->td_proc))
1309 			/* Not allowed to set ownership. */
1310 			return (ENOTTY);
1311 
1312 		/* Temporarily unlock the TTY to set ownership. */
1313 		tty_unlock(tp);
1314 		error = fsetown(*(int *)data, &tp->t_sigio);
1315 		tty_lock(tp);
1316 		return (error);
1317 	case FIOGETOWN:
1318 		if (tp->t_session != NULL && !tty_is_ctty(tp, td->td_proc))
1319 			/* Not allowed to set ownership. */
1320 			return (ENOTTY);
1321 
1322 		/* Get ownership. */
1323 		*(int *)data = fgetown(&tp->t_sigio);
1324 		return (0);
1325 	case TIOCGETA:
1326 		/* Obtain terminal flags through tcgetattr(). */
1327 		bcopy(&tp->t_termios, data, sizeof(struct termios));
1328 		return (0);
1329 	case TIOCSETA:
1330 	case TIOCSETAW:
1331 	case TIOCSETAF: {
1332 		struct termios *t = data;
1333 
1334 		/*
1335 		 * Who makes up these funny rules? According to POSIX,
1336 		 * input baud rate is set equal to the output baud rate
1337 		 * when zero.
1338 		 */
1339 		if (t->c_ispeed == 0)
1340 			t->c_ispeed = t->c_ospeed;
1341 
1342 		/* Discard any unsupported bits. */
1343 		t->c_iflag &= TTYSUP_IFLAG;
1344 		t->c_oflag &= TTYSUP_OFLAG;
1345 		t->c_lflag &= TTYSUP_LFLAG;
1346 		t->c_cflag &= TTYSUP_CFLAG;
1347 
1348 		/* Set terminal flags through tcsetattr(). */
1349 		if (cmd == TIOCSETAW || cmd == TIOCSETAF) {
1350 			error = tty_drain(tp);
1351 			if (error)
1352 				return (error);
1353 			if (cmd == TIOCSETAF)
1354 				tty_flush(tp, FREAD);
1355 		}
1356 
1357 		/*
1358 		 * Only call param() when the flags really change.
1359 		 */
1360 		if ((t->c_cflag & CIGNORE) == 0 &&
1361 		    (tp->t_termios.c_cflag != t->c_cflag ||
1362 		    tp->t_termios.c_ispeed != t->c_ispeed ||
1363 		    tp->t_termios.c_ospeed != t->c_ospeed)) {
1364 			error = ttydevsw_param(tp, t);
1365 			if (error)
1366 				return (error);
1367 
1368 			/* XXX: CLOCAL? */
1369 
1370 			tp->t_termios.c_cflag = t->c_cflag & ~CIGNORE;
1371 			tp->t_termios.c_ispeed = t->c_ispeed;
1372 			tp->t_termios.c_ospeed = t->c_ospeed;
1373 
1374 			/* Baud rate has changed - update watermarks. */
1375 			tty_watermarks(tp);
1376 		}
1377 
1378 		/* Copy new non-device driver parameters. */
1379 		tp->t_termios.c_iflag = t->c_iflag;
1380 		tp->t_termios.c_oflag = t->c_oflag;
1381 		tp->t_termios.c_lflag = t->c_lflag;
1382 		bcopy(t->c_cc, &tp->t_termios.c_cc, sizeof(t->c_cc));
1383 
1384 		ttydisc_optimize(tp);
1385 
1386 		if ((t->c_lflag & ICANON) == 0) {
1387 			/*
1388 			 * When in non-canonical mode, wake up all
1389 			 * readers. Canonicalize any partial input. VMIN
1390 			 * and VTIME could also be adjusted.
1391 			 */
1392 			ttyinq_canonicalize(&tp->t_inq);
1393 			tty_wakeup(tp, FREAD);
1394 		}
1395 
1396 		/*
1397 		 * For packet mode: notify the PTY consumer that VSTOP
1398 		 * and VSTART may have been changed.
1399 		 */
1400 		if (tp->t_termios.c_iflag & IXON &&
1401 		    tp->t_termios.c_cc[VSTOP] == CTRL('S') &&
1402 		    tp->t_termios.c_cc[VSTART] == CTRL('Q'))
1403 			ttydevsw_pktnotify(tp, TIOCPKT_DOSTOP);
1404 		else
1405 			ttydevsw_pktnotify(tp, TIOCPKT_NOSTOP);
1406 		return (0);
1407 	}
1408 	case TIOCGETD:
1409 		/* For compatibility - we only support TTYDISC. */
1410 		*(int *)data = TTYDISC;
1411 		return (0);
1412 	case TIOCGPGRP:
1413 		if (!tty_is_ctty(tp, td->td_proc))
1414 			return (ENOTTY);
1415 
1416 		if (tp->t_pgrp != NULL)
1417 			*(int *)data = tp->t_pgrp->pg_id;
1418 		else
1419 			*(int *)data = NO_PID;
1420 		return (0);
1421 	case TIOCGSID:
1422 		if (!tty_is_ctty(tp, td->td_proc))
1423 			return (ENOTTY);
1424 
1425 		MPASS(tp->t_session);
1426 		*(int *)data = tp->t_session->s_sid;
1427 		return (0);
1428 	case TIOCSCTTY: {
1429 		struct proc *p = td->td_proc;
1430 
1431 		/* XXX: This looks awful. */
1432 		tty_unlock(tp);
1433 		sx_xlock(&proctree_lock);
1434 		tty_lock(tp);
1435 
1436 		if (!SESS_LEADER(p)) {
1437 			/* Only the session leader may do this. */
1438 			sx_xunlock(&proctree_lock);
1439 			return (EPERM);
1440 		}
1441 
1442 		if (tp->t_session != NULL && tp->t_session == p->p_session) {
1443 			/* This is already our controlling TTY. */
1444 			sx_xunlock(&proctree_lock);
1445 			return (0);
1446 		}
1447 
1448 		if (!SESS_LEADER(p) || p->p_session->s_ttyvp != NULL ||
1449 		    (tp->t_session != NULL && tp->t_session->s_ttyvp != NULL)) {
1450 			/*
1451 			 * There is already a relation between a TTY and
1452 			 * a session, or the caller is not the session
1453 			 * leader.
1454 			 *
1455 			 * Allow the TTY to be stolen when the vnode is
1456 			 * NULL, but the reference to the TTY is still
1457 			 * active.
1458 			 */
1459 			sx_xunlock(&proctree_lock);
1460 			return (EPERM);
1461 		}
1462 
1463 		/* Connect the session to the TTY. */
1464 		tp->t_session = p->p_session;
1465 		tp->t_session->s_ttyp = tp;
1466 		tp->t_sessioncnt++;
1467 		sx_xunlock(&proctree_lock);
1468 
1469 		/* Assign foreground process group. */
1470 		tp->t_pgrp = p->p_pgrp;
1471 		PROC_LOCK(p);
1472 		p->p_flag |= P_CONTROLT;
1473 		PROC_UNLOCK(p);
1474 
1475 		return (0);
1476 	}
1477 	case TIOCSPGRP: {
1478 		struct pgrp *pg;
1479 
1480 		/*
1481 		 * XXX: Temporarily unlock the TTY to locate the process
1482 		 * group. This code would be lot nicer if we would ever
1483 		 * decompose proctree_lock.
1484 		 */
1485 		tty_unlock(tp);
1486 		sx_slock(&proctree_lock);
1487 		pg = pgfind(*(int *)data);
1488 		if (pg != NULL)
1489 			PGRP_UNLOCK(pg);
1490 		if (pg == NULL || pg->pg_session != td->td_proc->p_session) {
1491 			sx_sunlock(&proctree_lock);
1492 			tty_lock(tp);
1493 			return (EPERM);
1494 		}
1495 		tty_lock(tp);
1496 
1497 		/*
1498 		 * Determine if this TTY is the controlling TTY after
1499 		 * relocking the TTY.
1500 		 */
1501 		if (!tty_is_ctty(tp, td->td_proc)) {
1502 			sx_sunlock(&proctree_lock);
1503 			return (ENOTTY);
1504 		}
1505 		tp->t_pgrp = pg;
1506 		sx_sunlock(&proctree_lock);
1507 
1508 		/* Wake up the background process groups. */
1509 		cv_broadcast(&tp->t_bgwait);
1510 		return (0);
1511 	}
1512 	case TIOCFLUSH: {
1513 		int flags = *(int *)data;
1514 
1515 		if (flags == 0)
1516 			flags = (FREAD|FWRITE);
1517 		else
1518 			flags &= (FREAD|FWRITE);
1519 		tty_flush(tp, flags);
1520 		return (0);
1521 	}
1522 	case TIOCDRAIN:
1523 		/* Drain TTY output. */
1524 		return tty_drain(tp);
1525 	case TIOCCONS:
1526 		/* Set terminal as console TTY. */
1527 		if (*(int *)data) {
1528 			error = priv_check(td, PRIV_TTY_CONSOLE);
1529 			if (error)
1530 				return (error);
1531 
1532 			/*
1533 			 * XXX: constty should really need to be locked!
1534 			 * XXX: allow disconnected constty's to be stolen!
1535 			 */
1536 
1537 			if (constty == tp)
1538 				return (0);
1539 			if (constty != NULL)
1540 				return (EBUSY);
1541 
1542 			tty_unlock(tp);
1543 			constty_set(tp);
1544 			tty_lock(tp);
1545 		} else if (constty == tp) {
1546 			constty_clear();
1547 		}
1548 		return (0);
1549 	case TIOCGWINSZ:
1550 		/* Obtain window size. */
1551 		bcopy(&tp->t_winsize, data, sizeof(struct winsize));
1552 		return (0);
1553 	case TIOCSWINSZ:
1554 		/* Set window size. */
1555 		if (bcmp(&tp->t_winsize, data, sizeof(struct winsize)) == 0)
1556 			return (0);
1557 		bcopy(data, &tp->t_winsize, sizeof(struct winsize));
1558 		tty_signal_pgrp(tp, SIGWINCH);
1559 		return (0);
1560 	case TIOCEXCL:
1561 		tp->t_flags |= TF_EXCLUDE;
1562 		return (0);
1563 	case TIOCNXCL:
1564 		tp->t_flags &= ~TF_EXCLUDE;
1565 		return (0);
1566 	case TIOCOUTQ:
1567 		*(unsigned int *)data = ttyoutq_bytesused(&tp->t_outq);
1568 		return (0);
1569 	case TIOCSTOP:
1570 		tp->t_flags |= TF_STOPPED;
1571 		ttydevsw_pktnotify(tp, TIOCPKT_STOP);
1572 		return (0);
1573 	case TIOCSTART:
1574 		tp->t_flags &= ~TF_STOPPED;
1575 		ttydevsw_outwakeup(tp);
1576 		ttydevsw_pktnotify(tp, TIOCPKT_START);
1577 		return (0);
1578 	case TIOCSTAT:
1579 		tty_info(tp);
1580 		return (0);
1581 	}
1582 
1583 #ifdef COMPAT_43TTY
1584 	return tty_ioctl_compat(tp, cmd, data, td);
1585 #else /* !COMPAT_43TTY */
1586 	return (ENOIOCTL);
1587 #endif /* COMPAT_43TTY */
1588 }
1589 
1590 int
1591 tty_ioctl(struct tty *tp, u_long cmd, void *data, struct thread *td)
1592 {
1593 	int error;
1594 
1595 	tty_lock_assert(tp, MA_OWNED);
1596 
1597 	if (tty_gone(tp))
1598 		return (ENXIO);
1599 
1600 	error = ttydevsw_ioctl(tp, cmd, data, td);
1601 	if (error == ENOIOCTL)
1602 		error = tty_generic_ioctl(tp, cmd, data, td);
1603 
1604 	return (error);
1605 }
1606 
1607 dev_t
1608 tty_udev(struct tty *tp)
1609 {
1610 	if (tp->t_dev)
1611 		return dev2udev(tp->t_dev);
1612 	else
1613 		return NODEV;
1614 }
1615 
1616 int
1617 tty_checkoutq(struct tty *tp)
1618 {
1619 
1620 	/* 256 bytes should be enough to print a log message. */
1621 	return (ttyoutq_bytesleft(&tp->t_outq) >= 256);
1622 }
1623 
1624 void
1625 tty_hiwat_in_block(struct tty *tp)
1626 {
1627 
1628 	if ((tp->t_flags & TF_HIWAT_IN) == 0 &&
1629 	    tp->t_termios.c_iflag & IXOFF &&
1630 	    tp->t_termios.c_cc[VSTOP] != _POSIX_VDISABLE) {
1631 		/*
1632 		 * Input flow control. Only enter the high watermark when we
1633 		 * can successfully store the VSTOP character.
1634 		 */
1635 		if (ttyoutq_write_nofrag(&tp->t_outq,
1636 		    &tp->t_termios.c_cc[VSTOP], 1) == 0)
1637 			tp->t_flags |= TF_HIWAT_IN;
1638 	} else {
1639 		/* No input flow control. */
1640 		tp->t_flags |= TF_HIWAT_IN;
1641 	}
1642 }
1643 
1644 void
1645 tty_hiwat_in_unblock(struct tty *tp)
1646 {
1647 
1648 	if (tp->t_flags & TF_HIWAT_IN &&
1649 	    tp->t_termios.c_iflag & IXOFF &&
1650 	    tp->t_termios.c_cc[VSTART] != _POSIX_VDISABLE) {
1651 		/*
1652 		 * Input flow control. Only leave the high watermark when we
1653 		 * can successfully store the VSTART character.
1654 		 */
1655 		if (ttyoutq_write_nofrag(&tp->t_outq,
1656 		    &tp->t_termios.c_cc[VSTART], 1) == 0)
1657 			tp->t_flags &= ~TF_HIWAT_IN;
1658 	} else {
1659 		/* No input flow control. */
1660 		tp->t_flags &= ~TF_HIWAT_IN;
1661 	}
1662 
1663 	if (!tty_gone(tp))
1664 		ttydevsw_inwakeup(tp);
1665 }
1666 
1667 /*
1668  * TTY hooks interface.
1669  */
1670 
1671 static int
1672 ttyhook_defrint(struct tty *tp, char c, int flags)
1673 {
1674 
1675 	if (ttyhook_rint_bypass(tp, &c, 1) != 1)
1676 		return (-1);
1677 
1678 	return (0);
1679 }
1680 
1681 int
1682 ttyhook_register(struct tty **rtp, struct proc *p, int fd,
1683     struct ttyhook *th, void *softc)
1684 {
1685 	struct tty *tp;
1686 	struct file *fp;
1687 	struct cdev *dev;
1688 	struct cdevsw *cdp;
1689 	struct filedesc *fdp;
1690 	int error;
1691 
1692 	/* Validate the file descriptor. */
1693 	if ((fdp = p->p_fd) == NULL)
1694 		return (EBADF);
1695 	FILEDESC_SLOCK(fdp);
1696 	if ((fp = fget_locked(fdp, fd)) == NULL || fp->f_ops == &badfileops) {
1697 		FILEDESC_SUNLOCK(fdp);
1698 		return (EBADF);
1699 	}
1700 
1701 	/* Make sure the vnode is bound to a character device. */
1702 	error = EINVAL;
1703 	if (fp->f_type != DTYPE_VNODE || fp->f_vnode->v_type != VCHR ||
1704 	    fp->f_vnode->v_rdev == NULL)
1705 		goto done1;
1706 	dev = fp->f_vnode->v_rdev;
1707 
1708 	/* Make sure it is a TTY. */
1709 	cdp = dev_refthread(dev);
1710 	if (cdp == NULL)
1711 		goto done1;
1712 	if (cdp != &ttydev_cdevsw)
1713 		goto done2;
1714 	tp = dev->si_drv1;
1715 
1716 	/* Try to attach the hook to the TTY. */
1717 	error = EBUSY;
1718 	tty_lock(tp);
1719 	MPASS((tp->t_hook == NULL) == ((tp->t_flags & TF_HOOK) == 0));
1720 	if (tp->t_flags & TF_HOOK)
1721 		goto done3;
1722 
1723 	tp->t_flags |= TF_HOOK;
1724 	tp->t_hook = th;
1725 	tp->t_hooksoftc = softc;
1726 	*rtp = tp;
1727 	error = 0;
1728 
1729 	/* Maybe we can switch into bypass mode now. */
1730 	ttydisc_optimize(tp);
1731 
1732 	/* Silently convert rint() calls to rint_bypass() when possible. */
1733 	if (!ttyhook_hashook(tp, rint) && ttyhook_hashook(tp, rint_bypass))
1734 		th->th_rint = ttyhook_defrint;
1735 
1736 done3:	tty_unlock(tp);
1737 done2:	dev_relthread(dev);
1738 done1:	FILEDESC_SUNLOCK(fdp);
1739 	return (error);
1740 }
1741 
1742 void
1743 ttyhook_unregister(struct tty *tp)
1744 {
1745 
1746 	tty_lock_assert(tp, MA_OWNED);
1747 	MPASS(tp->t_flags & TF_HOOK);
1748 
1749 	/* Disconnect the hook. */
1750 	tp->t_flags &= ~TF_HOOK;
1751 	tp->t_hook = NULL;
1752 
1753 	/* Maybe we need to leave bypass mode. */
1754 	ttydisc_optimize(tp);
1755 
1756 	/* Maybe deallocate the TTY as well. */
1757 	tty_rel_free(tp);
1758 }
1759 
1760 /*
1761  * /dev/console handling.
1762  */
1763 
1764 static int
1765 ttyconsdev_open(struct cdev *dev, int oflags, int devtype, struct thread *td)
1766 {
1767 	struct tty *tp;
1768 
1769 	/* System has no console device. */
1770 	if (dev_console_filename == NULL)
1771 		return (ENXIO);
1772 
1773 	/* Look up corresponding TTY by device name. */
1774 	sx_slock(&tty_list_sx);
1775 	TAILQ_FOREACH(tp, &tty_list, t_list) {
1776 		if (strcmp(dev_console_filename, tty_devname(tp)) == 0) {
1777 			dev_console->si_drv1 = tp;
1778 			break;
1779 		}
1780 	}
1781 	sx_sunlock(&tty_list_sx);
1782 
1783 	/* System console has no TTY associated. */
1784 	if (dev_console->si_drv1 == NULL)
1785 		return (ENXIO);
1786 
1787 	return (ttydev_open(dev, oflags, devtype, td));
1788 }
1789 
1790 static int
1791 ttyconsdev_write(struct cdev *dev, struct uio *uio, int ioflag)
1792 {
1793 
1794 	log_console(uio);
1795 
1796 	return (ttydev_write(dev, uio, ioflag));
1797 }
1798 
1799 /*
1800  * /dev/console is a little different than normal TTY's. Unlike regular
1801  * TTY device nodes, this device node will not revoke the entire TTY
1802  * upon closure and all data written to it will be logged.
1803  */
1804 static struct cdevsw ttyconsdev_cdevsw = {
1805 	.d_version	= D_VERSION,
1806 	.d_open		= ttyconsdev_open,
1807 	.d_read		= ttydev_read,
1808 	.d_write	= ttyconsdev_write,
1809 	.d_ioctl	= ttydev_ioctl,
1810 	.d_kqfilter	= ttydev_kqfilter,
1811 	.d_poll		= ttydev_poll,
1812 	.d_mmap		= ttydev_mmap,
1813 	.d_name		= "ttyconsdev",
1814 	.d_flags	= D_TTY,
1815 };
1816 
1817 static void
1818 ttyconsdev_init(void *unused)
1819 {
1820 
1821 	dev_console = make_dev(&ttyconsdev_cdevsw, 0, UID_ROOT, GID_WHEEL,
1822 	    0600, "console");
1823 }
1824 
1825 SYSINIT(tty, SI_SUB_DRIVERS, SI_ORDER_FIRST, ttyconsdev_init, NULL);
1826 
1827 void
1828 ttyconsdev_select(const char *name)
1829 {
1830 
1831 	dev_console_filename = name;
1832 }
1833 
1834 /*
1835  * Debugging routines.
1836  */
1837 
1838 #include "opt_ddb.h"
1839 #ifdef DDB
1840 #include <ddb/ddb.h>
1841 #include <ddb/db_sym.h>
1842 
1843 static struct {
1844 	int flag;
1845 	char val;
1846 } ttystates[] = {
1847 #if 0
1848 	{ TF_NOPREFIX,	'N' },
1849 #endif
1850 	{ TF_INITLOCK,	'I' },
1851 	{ TF_CALLOUT,	'C' },
1852 
1853 	/* Keep these together -> 'Oi' and 'Oo'. */
1854 	{ TF_OPENED,	'O' },
1855 	{ TF_OPENED_IN,	'i' },
1856 	{ TF_OPENED_OUT,'o' },
1857 
1858 	{ TF_GONE,	'G' },
1859 	{ TF_OPENCLOSE,	'B' },
1860 	{ TF_ASYNC,	'Y' },
1861 	{ TF_LITERAL,	'L' },
1862 
1863 	/* Keep these together -> 'Hi' and 'Ho'. */
1864 	{ TF_HIWAT,	'H' },
1865 	{ TF_HIWAT_IN,	'i' },
1866 	{ TF_HIWAT_OUT,	'o' },
1867 
1868 	{ TF_STOPPED,	'S' },
1869 	{ TF_EXCLUDE,	'X' },
1870 	{ TF_BYPASS,	'l' },
1871 	{ TF_ZOMBIE,	'Z' },
1872 	{ TF_HOOK,	's' },
1873 
1874 	{ 0,	       '\0' },
1875 };
1876 
1877 #define	TTY_FLAG_BITS \
1878 	"\20\1NOPREFIX\2INITLOCK\3CALLOUT\4OPENED_IN\5OPENED_OUT\6GONE" \
1879 	"\7OPENCLOSE\10ASYNC\11LITERAL\12HIWAT_IN\13HIWAT_OUT\14STOPPED" \
1880 	"\15EXCLUDE\16BYPASS\17ZOMBIE\20HOOK"
1881 
1882 #define DB_PRINTSYM(name, addr) \
1883 	db_printf("%s  " #name ": ", sep); \
1884 	db_printsym((db_addr_t) addr, DB_STGY_ANY); \
1885 	db_printf("\n");
1886 
1887 static void
1888 _db_show_devsw(const char *sep, const struct ttydevsw *tsw)
1889 {
1890 	db_printf("%sdevsw: ", sep);
1891 	db_printsym((db_addr_t)tsw, DB_STGY_ANY);
1892 	db_printf(" (%p)\n", tsw);
1893 	DB_PRINTSYM(open, tsw->tsw_open);
1894 	DB_PRINTSYM(close, tsw->tsw_close);
1895 	DB_PRINTSYM(outwakeup, tsw->tsw_outwakeup);
1896 	DB_PRINTSYM(inwakeup, tsw->tsw_inwakeup);
1897 	DB_PRINTSYM(ioctl, tsw->tsw_ioctl);
1898 	DB_PRINTSYM(param, tsw->tsw_param);
1899 	DB_PRINTSYM(modem, tsw->tsw_modem);
1900 	DB_PRINTSYM(mmap, tsw->tsw_mmap);
1901 	DB_PRINTSYM(pktnotify, tsw->tsw_pktnotify);
1902 	DB_PRINTSYM(free, tsw->tsw_free);
1903 }
1904 static void
1905 _db_show_hooks(const char *sep, const struct ttyhook *th)
1906 {
1907 	db_printf("%shook: ", sep);
1908 	db_printsym((db_addr_t)th, DB_STGY_ANY);
1909 	db_printf(" (%p)\n", th);
1910 	if (th == NULL)
1911 		return;
1912 	DB_PRINTSYM(rint, th->th_rint);
1913 	DB_PRINTSYM(rint_bypass, th->th_rint_bypass);
1914 	DB_PRINTSYM(rint_done, th->th_rint_done);
1915 	DB_PRINTSYM(rint_poll, th->th_rint_poll);
1916 	DB_PRINTSYM(getc_inject, th->th_getc_inject);
1917 	DB_PRINTSYM(getc_capture, th->th_getc_capture);
1918 	DB_PRINTSYM(getc_poll, th->th_getc_poll);
1919 	DB_PRINTSYM(close, th->th_close);
1920 }
1921 
1922 static void
1923 _db_show_termios(const char *name, const struct termios *t)
1924 {
1925 
1926 	db_printf("%s: iflag 0x%x oflag 0x%x cflag 0x%x "
1927 	    "lflag 0x%x ispeed %u ospeed %u\n", name,
1928 	    t->c_iflag, t->c_oflag, t->c_cflag, t->c_lflag,
1929 	    t->c_ispeed, t->c_ospeed);
1930 }
1931 
1932 /* DDB command to show TTY statistics. */
1933 DB_SHOW_COMMAND(tty, db_show_tty)
1934 {
1935 	struct tty *tp;
1936 
1937 	if (!have_addr) {
1938 		db_printf("usage: show tty <addr>\n");
1939 		return;
1940 	}
1941 	tp = (struct tty *)addr;
1942 
1943 	db_printf("0x%p: %s\n", tp, tty_devname(tp));
1944 	db_printf("\tmtx: %p\n", tp->t_mtx);
1945 	db_printf("\tflags: %b\n", tp->t_flags, TTY_FLAG_BITS);
1946 	db_printf("\trevokecnt: %u\n", tp->t_revokecnt);
1947 
1948 	/* Buffering mechanisms. */
1949 	db_printf("\tinq: %p begin %u linestart %u reprint %u end %u "
1950 	    "nblocks %u quota %u\n", &tp->t_inq, tp->t_inq.ti_begin,
1951 	    tp->t_inq.ti_linestart, tp->t_inq.ti_reprint, tp->t_inq.ti_end,
1952 	    tp->t_inq.ti_nblocks, tp->t_inq.ti_quota);
1953 	db_printf("\toutq: %p begin %u end %u nblocks %u quota %u\n",
1954 	    &tp->t_outq, tp->t_outq.to_begin, tp->t_outq.to_end,
1955 	    tp->t_outq.to_nblocks, tp->t_outq.to_quota);
1956 	db_printf("\tinlow: %zu\n", tp->t_inlow);
1957 	db_printf("\toutlow: %zu\n", tp->t_outlow);
1958 	_db_show_termios("\ttermios", &tp->t_termios);
1959 	db_printf("\twinsize: row %u col %u xpixel %u ypixel %u\n",
1960 	    tp->t_winsize.ws_row, tp->t_winsize.ws_col,
1961 	    tp->t_winsize.ws_xpixel, tp->t_winsize.ws_ypixel);
1962 	db_printf("\tcolumn: %u\n", tp->t_column);
1963 	db_printf("\twritepos: %u\n", tp->t_writepos);
1964 	db_printf("\tcompatflags: 0x%x\n", tp->t_compatflags);
1965 
1966 	/* Init/lock-state devices. */
1967 	_db_show_termios("\ttermios_init_in", &tp->t_termios_init_in);
1968 	_db_show_termios("\ttermios_init_out", &tp->t_termios_init_out);
1969 	_db_show_termios("\ttermios_lock_in", &tp->t_termios_lock_in);
1970 	_db_show_termios("\ttermios_lock_out", &tp->t_termios_lock_out);
1971 
1972 	/* Hooks */
1973 	_db_show_devsw("\t", tp->t_devsw);
1974 	_db_show_hooks("\t", tp->t_hook);
1975 
1976 	/* Process info. */
1977 	db_printf("\tpgrp: %p gid %d jobc %d\n", tp->t_pgrp,
1978 	    tp->t_pgrp ? tp->t_pgrp->pg_id : 0,
1979 	    tp->t_pgrp ? tp->t_pgrp->pg_jobc : 0);
1980 	db_printf("\tsession: %p", tp->t_session);
1981 	if (tp->t_session != NULL)
1982 	    db_printf(" count %u leader %p tty %p sid %d login %s",
1983 		tp->t_session->s_count, tp->t_session->s_leader,
1984 		tp->t_session->s_ttyp, tp->t_session->s_sid,
1985 		tp->t_session->s_login);
1986 	db_printf("\n");
1987 	db_printf("\tsessioncnt: %u\n", tp->t_sessioncnt);
1988 	db_printf("\tdevswsoftc: %p\n", tp->t_devswsoftc);
1989 	db_printf("\thooksoftc: %p\n", tp->t_hooksoftc);
1990 	db_printf("\tdev: %p\n", tp->t_dev);
1991 }
1992 
1993 /* DDB command to list TTYs. */
1994 DB_SHOW_ALL_COMMAND(ttys, db_show_all_ttys)
1995 {
1996 	struct tty *tp;
1997 	size_t isiz, osiz;
1998 	int i, j;
1999 
2000 	/* Make the output look like `pstat -t'. */
2001 	db_printf("PTR        ");
2002 #if defined(__LP64__)
2003 	db_printf("        ");
2004 #endif
2005 	db_printf("      LINE   INQ  CAN  LIN  LOW  OUTQ  USE  LOW   "
2006 	    "COL  SESS  PGID STATE\n");
2007 
2008 	TAILQ_FOREACH(tp, &tty_list, t_list) {
2009 		isiz = tp->t_inq.ti_nblocks * TTYINQ_DATASIZE;
2010 		osiz = tp->t_outq.to_nblocks * TTYOUTQ_DATASIZE;
2011 
2012 		db_printf("%p %10s %5zu %4u %4u %4zu %5zu %4u %4zu %5u %5d %5d ",
2013 		    tp,
2014 		    tty_devname(tp),
2015 		    isiz,
2016 		    tp->t_inq.ti_linestart - tp->t_inq.ti_begin,
2017 		    tp->t_inq.ti_end - tp->t_inq.ti_linestart,
2018 		    isiz - tp->t_inlow,
2019 		    osiz,
2020 		    tp->t_outq.to_end - tp->t_outq.to_begin,
2021 		    osiz - tp->t_outlow,
2022 		    MIN(tp->t_column, 99999),
2023 		    tp->t_session ? tp->t_session->s_sid : 0,
2024 		    tp->t_pgrp ? tp->t_pgrp->pg_id : 0);
2025 
2026 		/* Flag bits. */
2027 		for (i = j = 0; ttystates[i].flag; i++)
2028 			if (tp->t_flags & ttystates[i].flag) {
2029 				db_printf("%c", ttystates[i].val);
2030 				j++;
2031 			}
2032 		if (j == 0)
2033 			db_printf("-");
2034 		db_printf("\n");
2035 	}
2036 }
2037 #endif /* DDB */
2038