xref: /freebsd/sys/kern/tty.c (revision d34048812292b714a0bf99967270d18fe3097c62)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2008 Ed Schouten <ed@FreeBSD.org>
5  * All rights reserved.
6  *
7  * Portions of this software were developed under sponsorship from Snow
8  * B.V., the Netherlands.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
34 
35 #include "opt_capsicum.h"
36 #include "opt_printf.h"
37 
38 #include <sys/param.h>
39 #include <sys/capsicum.h>
40 #include <sys/conf.h>
41 #include <sys/cons.h>
42 #include <sys/fcntl.h>
43 #include <sys/file.h>
44 #include <sys/filedesc.h>
45 #include <sys/filio.h>
46 #ifdef COMPAT_43TTY
47 #include <sys/ioctl_compat.h>
48 #endif /* COMPAT_43TTY */
49 #include <sys/kernel.h>
50 #include <sys/limits.h>
51 #include <sys/malloc.h>
52 #include <sys/mount.h>
53 #include <sys/poll.h>
54 #include <sys/priv.h>
55 #include <sys/proc.h>
56 #include <sys/serial.h>
57 #include <sys/signal.h>
58 #include <sys/stat.h>
59 #include <sys/sx.h>
60 #include <sys/sysctl.h>
61 #include <sys/systm.h>
62 #include <sys/tty.h>
63 #include <sys/ttycom.h>
64 #define TTYDEFCHARS
65 #include <sys/ttydefaults.h>
66 #undef TTYDEFCHARS
67 #include <sys/ucred.h>
68 #include <sys/vnode.h>
69 
70 #include <machine/stdarg.h>
71 
72 static MALLOC_DEFINE(M_TTY, "tty", "tty device");
73 
74 static void tty_rel_free(struct tty *tp);
75 
76 static TAILQ_HEAD(, tty) tty_list = TAILQ_HEAD_INITIALIZER(tty_list);
77 static struct sx tty_list_sx;
78 SX_SYSINIT(tty_list, &tty_list_sx, "tty list");
79 static unsigned int tty_list_count = 0;
80 
81 /* Character device of /dev/console. */
82 static struct cdev	*dev_console;
83 static const char	*dev_console_filename;
84 
85 /*
86  * Flags that are supported and stored by this implementation.
87  */
88 #define TTYSUP_IFLAG	(IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK|ISTRIP|\
89 			INLCR|IGNCR|ICRNL|IXON|IXOFF|IXANY|IMAXBEL)
90 #define TTYSUP_OFLAG	(OPOST|ONLCR|TAB3|ONOEOT|OCRNL|ONOCR|ONLRET)
91 #define TTYSUP_LFLAG	(ECHOKE|ECHOE|ECHOK|ECHO|ECHONL|ECHOPRT|\
92 			ECHOCTL|ISIG|ICANON|ALTWERASE|IEXTEN|TOSTOP|\
93 			FLUSHO|NOKERNINFO|NOFLSH)
94 #define TTYSUP_CFLAG	(CIGNORE|CSIZE|CSTOPB|CREAD|PARENB|PARODD|\
95 			HUPCL|CLOCAL|CCTS_OFLOW|CRTS_IFLOW|CDTR_IFLOW|\
96 			CDSR_OFLOW|CCAR_OFLOW)
97 
98 #define	TTY_CALLOUT(tp,d) (dev2unit(d) & TTYUNIT_CALLOUT)
99 
100 static int  tty_drainwait = 5 * 60;
101 SYSCTL_INT(_kern, OID_AUTO, tty_drainwait, CTLFLAG_RWTUN,
102     &tty_drainwait, 0, "Default output drain timeout in seconds");
103 
104 /*
105  * Set TTY buffer sizes.
106  */
107 
108 #define	TTYBUF_MAX	65536
109 
110 #ifdef PRINTF_BUFR_SIZE
111 #define	TTY_PRBUF_SIZE	PRINTF_BUFR_SIZE
112 #else
113 #define	TTY_PRBUF_SIZE	256
114 #endif
115 
116 /*
117  * Allocate buffer space if necessary, and set low watermarks, based on speed.
118  * Note that the ttyxxxq_setsize() functions may drop and then reacquire the tty
119  * lock during memory allocation.  They will return ENXIO if the tty disappears
120  * while unlocked.
121  */
122 static int
123 tty_watermarks(struct tty *tp)
124 {
125 	size_t bs = 0;
126 	int error;
127 
128 	/* Provide an input buffer for 2 seconds of data. */
129 	if (tp->t_termios.c_cflag & CREAD)
130 		bs = MIN(tp->t_termios.c_ispeed / 5, TTYBUF_MAX);
131 	error = ttyinq_setsize(&tp->t_inq, tp, bs);
132 	if (error != 0)
133 		return (error);
134 
135 	/* Set low watermark at 10% (when 90% is available). */
136 	tp->t_inlow = (ttyinq_getallocatedsize(&tp->t_inq) * 9) / 10;
137 
138 	/* Provide an output buffer for 2 seconds of data. */
139 	bs = MIN(tp->t_termios.c_ospeed / 5, TTYBUF_MAX);
140 	error = ttyoutq_setsize(&tp->t_outq, tp, bs);
141 	if (error != 0)
142 		return (error);
143 
144 	/* Set low watermark at 10% (when 90% is available). */
145 	tp->t_outlow = (ttyoutq_getallocatedsize(&tp->t_outq) * 9) / 10;
146 
147 	return (0);
148 }
149 
150 static int
151 tty_drain(struct tty *tp, int leaving)
152 {
153 	sbintime_t timeout_at;
154 	size_t bytes;
155 	int error;
156 
157 	if (ttyhook_hashook(tp, getc_inject))
158 		/* buffer is inaccessible */
159 		return (0);
160 
161 	/*
162 	 * For close(), use the recent historic timeout of "1 second without
163 	 * making progress".  For tcdrain(), use t_drainwait as the timeout,
164 	 * with zero meaning "no timeout" which gives POSIX behavior.
165 	 */
166 	if (leaving)
167 		timeout_at = getsbinuptime() + SBT_1S;
168 	else if (tp->t_drainwait != 0)
169 		timeout_at = getsbinuptime() + SBT_1S * tp->t_drainwait;
170 	else
171 		timeout_at = 0;
172 
173 	/*
174 	 * Poll the output buffer and the hardware for completion, at 10 Hz.
175 	 * Polling is required for devices which are not able to signal an
176 	 * interrupt when the transmitter becomes idle (most USB serial devs).
177 	 * The unusual structure of this loop ensures we check for busy one more
178 	 * time after tty_timedwait() returns EWOULDBLOCK, so that success has
179 	 * higher priority than timeout if the IO completed in the last 100mS.
180 	 */
181 	error = 0;
182 	bytes = ttyoutq_bytesused(&tp->t_outq);
183 	for (;;) {
184 		if (ttyoutq_bytesused(&tp->t_outq) == 0 && !ttydevsw_busy(tp))
185 			return (0);
186 		if (error != 0)
187 			return (error);
188 		ttydevsw_outwakeup(tp);
189 		error = tty_timedwait(tp, &tp->t_outwait, hz / 10);
190 		if (error != 0 && error != EWOULDBLOCK)
191 			return (error);
192 		else if (timeout_at == 0 || getsbinuptime() < timeout_at)
193 			error = 0;
194 		else if (leaving && ttyoutq_bytesused(&tp->t_outq) < bytes) {
195 			/* In close, making progress, grant an extra second. */
196 			error = 0;
197 			timeout_at += SBT_1S;
198 			bytes = ttyoutq_bytesused(&tp->t_outq);
199 		}
200 	}
201 }
202 
203 /*
204  * Though ttydev_enter() and ttydev_leave() seem to be related, they
205  * don't have to be used together. ttydev_enter() is used by the cdev
206  * operations to prevent an actual operation from being processed when
207  * the TTY has been abandoned. ttydev_leave() is used by ttydev_open()
208  * and ttydev_close() to determine whether per-TTY data should be
209  * deallocated.
210  */
211 
212 static __inline int
213 ttydev_enter(struct tty *tp)
214 {
215 
216 	tty_lock(tp);
217 
218 	if (tty_gone(tp) || !tty_opened(tp)) {
219 		/* Device is already gone. */
220 		tty_unlock(tp);
221 		return (ENXIO);
222 	}
223 
224 	return (0);
225 }
226 
227 static void
228 ttydev_leave(struct tty *tp)
229 {
230 
231 	tty_lock_assert(tp, MA_OWNED);
232 
233 	if (tty_opened(tp) || tp->t_flags & TF_OPENCLOSE) {
234 		/* Device is still opened somewhere. */
235 		tty_unlock(tp);
236 		return;
237 	}
238 
239 	tp->t_flags |= TF_OPENCLOSE;
240 
241 	/* Stop asynchronous I/O. */
242 	funsetown(&tp->t_sigio);
243 
244 	/* Remove console TTY. */
245 	if (constty == tp)
246 		constty_clear();
247 
248 	/* Drain any output. */
249 	if (!tty_gone(tp))
250 		tty_drain(tp, 1);
251 
252 	ttydisc_close(tp);
253 
254 	/* Free i/o queues now since they might be large. */
255 	ttyinq_free(&tp->t_inq);
256 	tp->t_inlow = 0;
257 	ttyoutq_free(&tp->t_outq);
258 	tp->t_outlow = 0;
259 
260 	knlist_clear(&tp->t_inpoll.si_note, 1);
261 	knlist_clear(&tp->t_outpoll.si_note, 1);
262 
263 	if (!tty_gone(tp))
264 		ttydevsw_close(tp);
265 
266 	tp->t_flags &= ~TF_OPENCLOSE;
267 	cv_broadcast(&tp->t_dcdwait);
268 	tty_rel_free(tp);
269 }
270 
271 /*
272  * Operations that are exposed through the character device in /dev.
273  */
274 static int
275 ttydev_open(struct cdev *dev, int oflags, int devtype __unused,
276     struct thread *td)
277 {
278 	struct tty *tp;
279 	int error;
280 
281 	tp = dev->si_drv1;
282 	error = 0;
283 	tty_lock(tp);
284 	if (tty_gone(tp)) {
285 		/* Device is already gone. */
286 		tty_unlock(tp);
287 		return (ENXIO);
288 	}
289 
290 	/*
291 	 * Block when other processes are currently opening or closing
292 	 * the TTY.
293 	 */
294 	while (tp->t_flags & TF_OPENCLOSE) {
295 		error = tty_wait(tp, &tp->t_dcdwait);
296 		if (error != 0) {
297 			tty_unlock(tp);
298 			return (error);
299 		}
300 	}
301 	tp->t_flags |= TF_OPENCLOSE;
302 
303 	/*
304 	 * Make sure the "tty" and "cua" device cannot be opened at the
305 	 * same time.  The console is a "tty" device.
306 	 */
307 	if (TTY_CALLOUT(tp, dev)) {
308 		if (tp->t_flags & (TF_OPENED_CONS | TF_OPENED_IN)) {
309 			error = EBUSY;
310 			goto done;
311 		}
312 	} else {
313 		if (tp->t_flags & TF_OPENED_OUT) {
314 			error = EBUSY;
315 			goto done;
316 		}
317 	}
318 
319 	if (tp->t_flags & TF_EXCLUDE && priv_check(td, PRIV_TTY_EXCLUSIVE)) {
320 		error = EBUSY;
321 		goto done;
322 	}
323 
324 	if (!tty_opened(tp)) {
325 		/* Set proper termios flags. */
326 		if (TTY_CALLOUT(tp, dev))
327 			tp->t_termios = tp->t_termios_init_out;
328 		else
329 			tp->t_termios = tp->t_termios_init_in;
330 		ttydevsw_param(tp, &tp->t_termios);
331 		/* Prevent modem control on callout devices and /dev/console. */
332 		if (TTY_CALLOUT(tp, dev) || dev == dev_console)
333 			tp->t_termios.c_cflag |= CLOCAL;
334 
335 		ttydevsw_modem(tp, SER_DTR|SER_RTS, 0);
336 
337 		error = ttydevsw_open(tp);
338 		if (error != 0)
339 			goto done;
340 
341 		ttydisc_open(tp);
342 		error = tty_watermarks(tp);
343 		if (error != 0)
344 			goto done;
345 	}
346 
347 	/* Wait for Carrier Detect. */
348 	if ((oflags & O_NONBLOCK) == 0 &&
349 	    (tp->t_termios.c_cflag & CLOCAL) == 0) {
350 		while ((ttydevsw_modem(tp, 0, 0) & SER_DCD) == 0) {
351 			error = tty_wait(tp, &tp->t_dcdwait);
352 			if (error != 0)
353 				goto done;
354 		}
355 	}
356 
357 	if (dev == dev_console)
358 		tp->t_flags |= TF_OPENED_CONS;
359 	else if (TTY_CALLOUT(tp, dev))
360 		tp->t_flags |= TF_OPENED_OUT;
361 	else
362 		tp->t_flags |= TF_OPENED_IN;
363 	MPASS((tp->t_flags & (TF_OPENED_CONS | TF_OPENED_IN)) == 0 ||
364 	    (tp->t_flags & TF_OPENED_OUT) == 0);
365 
366 done:	tp->t_flags &= ~TF_OPENCLOSE;
367 	cv_broadcast(&tp->t_dcdwait);
368 	ttydev_leave(tp);
369 
370 	return (error);
371 }
372 
373 static int
374 ttydev_close(struct cdev *dev, int fflag, int devtype __unused,
375     struct thread *td __unused)
376 {
377 	struct tty *tp = dev->si_drv1;
378 
379 	tty_lock(tp);
380 
381 	/*
382 	 * Don't actually close the device if it is being used as the
383 	 * console.
384 	 */
385 	MPASS((tp->t_flags & (TF_OPENED_CONS | TF_OPENED_IN)) == 0 ||
386 	    (tp->t_flags & TF_OPENED_OUT) == 0);
387 	if (dev == dev_console)
388 		tp->t_flags &= ~TF_OPENED_CONS;
389 	else
390 		tp->t_flags &= ~(TF_OPENED_IN|TF_OPENED_OUT);
391 
392 	if (tp->t_flags & TF_OPENED) {
393 		tty_unlock(tp);
394 		return (0);
395 	}
396 
397 	/* If revoking, flush output now to avoid draining it later. */
398 	if (fflag & FREVOKE)
399 		tty_flush(tp, FWRITE);
400 
401 	tp->t_flags &= ~TF_EXCLUDE;
402 
403 	/* Properly wake up threads that are stuck - revoke(). */
404 	tp->t_revokecnt++;
405 	tty_wakeup(tp, FREAD|FWRITE);
406 	cv_broadcast(&tp->t_bgwait);
407 	cv_broadcast(&tp->t_dcdwait);
408 
409 	ttydev_leave(tp);
410 
411 	return (0);
412 }
413 
414 static __inline int
415 tty_is_ctty(struct tty *tp, struct proc *p)
416 {
417 
418 	tty_lock_assert(tp, MA_OWNED);
419 
420 	return (p->p_session == tp->t_session && p->p_flag & P_CONTROLT);
421 }
422 
423 int
424 tty_wait_background(struct tty *tp, struct thread *td, int sig)
425 {
426 	struct proc *p = td->td_proc;
427 	struct pgrp *pg;
428 	ksiginfo_t ksi;
429 	int error;
430 
431 	MPASS(sig == SIGTTIN || sig == SIGTTOU);
432 	tty_lock_assert(tp, MA_OWNED);
433 
434 	for (;;) {
435 		PROC_LOCK(p);
436 		/*
437 		 * The process should only sleep, when:
438 		 * - This terminal is the controlling terminal
439 		 * - Its process group is not the foreground process
440 		 *   group
441 		 * - The parent process isn't waiting for the child to
442 		 *   exit
443 		 * - the signal to send to the process isn't masked
444 		 */
445 		if (!tty_is_ctty(tp, p) || p->p_pgrp == tp->t_pgrp) {
446 			/* Allow the action to happen. */
447 			PROC_UNLOCK(p);
448 			return (0);
449 		}
450 
451 		if (SIGISMEMBER(p->p_sigacts->ps_sigignore, sig) ||
452 		    SIGISMEMBER(td->td_sigmask, sig)) {
453 			/* Only allow them in write()/ioctl(). */
454 			PROC_UNLOCK(p);
455 			return (sig == SIGTTOU ? 0 : EIO);
456 		}
457 
458 		pg = p->p_pgrp;
459 		if (p->p_flag & P_PPWAIT || pg->pg_jobc == 0) {
460 			/* Don't allow the action to happen. */
461 			PROC_UNLOCK(p);
462 			return (EIO);
463 		}
464 		PROC_UNLOCK(p);
465 
466 		/*
467 		 * Send the signal and sleep until we're the new
468 		 * foreground process group.
469 		 */
470 		if (sig != 0) {
471 			ksiginfo_init(&ksi);
472 			ksi.ksi_code = SI_KERNEL;
473 			ksi.ksi_signo = sig;
474 			sig = 0;
475 		}
476 		PGRP_LOCK(pg);
477 		pgsignal(pg, ksi.ksi_signo, 1, &ksi);
478 		PGRP_UNLOCK(pg);
479 
480 		error = tty_wait(tp, &tp->t_bgwait);
481 		if (error)
482 			return (error);
483 	}
484 }
485 
486 static int
487 ttydev_read(struct cdev *dev, struct uio *uio, int ioflag)
488 {
489 	struct tty *tp = dev->si_drv1;
490 	int error;
491 
492 	error = ttydev_enter(tp);
493 	if (error)
494 		goto done;
495 	error = ttydisc_read(tp, uio, ioflag);
496 	tty_unlock(tp);
497 
498 	/*
499 	 * The read() call should not throw an error when the device is
500 	 * being destroyed. Silently convert it to an EOF.
501 	 */
502 done:	if (error == ENXIO)
503 		error = 0;
504 	return (error);
505 }
506 
507 static int
508 ttydev_write(struct cdev *dev, struct uio *uio, int ioflag)
509 {
510 	struct tty *tp = dev->si_drv1;
511 	int error;
512 
513 	error = ttydev_enter(tp);
514 	if (error)
515 		return (error);
516 
517 	if (tp->t_termios.c_lflag & TOSTOP) {
518 		error = tty_wait_background(tp, curthread, SIGTTOU);
519 		if (error)
520 			goto done;
521 	}
522 
523 	if (ioflag & IO_NDELAY && tp->t_flags & TF_BUSY_OUT) {
524 		/* Allow non-blocking writes to bypass serialization. */
525 		error = ttydisc_write(tp, uio, ioflag);
526 	} else {
527 		/* Serialize write() calls. */
528 		while (tp->t_flags & TF_BUSY_OUT) {
529 			error = tty_wait(tp, &tp->t_outserwait);
530 			if (error)
531 				goto done;
532 		}
533 
534 		tp->t_flags |= TF_BUSY_OUT;
535 		error = ttydisc_write(tp, uio, ioflag);
536 		tp->t_flags &= ~TF_BUSY_OUT;
537 		cv_signal(&tp->t_outserwait);
538 	}
539 
540 done:	tty_unlock(tp);
541 	return (error);
542 }
543 
544 static int
545 ttydev_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int fflag,
546     struct thread *td)
547 {
548 	struct tty *tp = dev->si_drv1;
549 	int error;
550 
551 	error = ttydev_enter(tp);
552 	if (error)
553 		return (error);
554 
555 	switch (cmd) {
556 	case TIOCCBRK:
557 	case TIOCCONS:
558 	case TIOCDRAIN:
559 	case TIOCEXCL:
560 	case TIOCFLUSH:
561 	case TIOCNXCL:
562 	case TIOCSBRK:
563 	case TIOCSCTTY:
564 	case TIOCSETA:
565 	case TIOCSETAF:
566 	case TIOCSETAW:
567 	case TIOCSPGRP:
568 	case TIOCSTART:
569 	case TIOCSTAT:
570 	case TIOCSTI:
571 	case TIOCSTOP:
572 	case TIOCSWINSZ:
573 #if 0
574 	case TIOCSDRAINWAIT:
575 	case TIOCSETD:
576 #endif
577 #ifdef COMPAT_43TTY
578 	case  TIOCLBIC:
579 	case  TIOCLBIS:
580 	case  TIOCLSET:
581 	case  TIOCSETC:
582 	case OTIOCSETD:
583 	case  TIOCSETN:
584 	case  TIOCSETP:
585 	case  TIOCSLTC:
586 #endif /* COMPAT_43TTY */
587 		/*
588 		 * If the ioctl() causes the TTY to be modified, let it
589 		 * wait in the background.
590 		 */
591 		error = tty_wait_background(tp, curthread, SIGTTOU);
592 		if (error)
593 			goto done;
594 	}
595 
596 	if (cmd == TIOCSETA || cmd == TIOCSETAW || cmd == TIOCSETAF) {
597 		struct termios *old = &tp->t_termios;
598 		struct termios *new = (struct termios *)data;
599 		struct termios *lock = TTY_CALLOUT(tp, dev) ?
600 		    &tp->t_termios_lock_out : &tp->t_termios_lock_in;
601 		int cc;
602 
603 		/*
604 		 * Lock state devices.  Just overwrite the values of the
605 		 * commands that are currently in use.
606 		 */
607 		new->c_iflag = (old->c_iflag & lock->c_iflag) |
608 		    (new->c_iflag & ~lock->c_iflag);
609 		new->c_oflag = (old->c_oflag & lock->c_oflag) |
610 		    (new->c_oflag & ~lock->c_oflag);
611 		new->c_cflag = (old->c_cflag & lock->c_cflag) |
612 		    (new->c_cflag & ~lock->c_cflag);
613 		new->c_lflag = (old->c_lflag & lock->c_lflag) |
614 		    (new->c_lflag & ~lock->c_lflag);
615 		for (cc = 0; cc < NCCS; ++cc)
616 			if (lock->c_cc[cc])
617 				new->c_cc[cc] = old->c_cc[cc];
618 		if (lock->c_ispeed)
619 			new->c_ispeed = old->c_ispeed;
620 		if (lock->c_ospeed)
621 			new->c_ospeed = old->c_ospeed;
622 	}
623 
624 	error = tty_ioctl(tp, cmd, data, fflag, td);
625 done:	tty_unlock(tp);
626 
627 	return (error);
628 }
629 
630 static int
631 ttydev_poll(struct cdev *dev, int events, struct thread *td)
632 {
633 	struct tty *tp = dev->si_drv1;
634 	int error, revents = 0;
635 
636 	error = ttydev_enter(tp);
637 	if (error)
638 		return ((events & (POLLIN|POLLRDNORM)) | POLLHUP);
639 
640 	if (events & (POLLIN|POLLRDNORM)) {
641 		/* See if we can read something. */
642 		if (ttydisc_read_poll(tp) > 0)
643 			revents |= events & (POLLIN|POLLRDNORM);
644 	}
645 
646 	if (tp->t_flags & TF_ZOMBIE) {
647 		/* Hangup flag on zombie state. */
648 		revents |= POLLHUP;
649 	} else if (events & (POLLOUT|POLLWRNORM)) {
650 		/* See if we can write something. */
651 		if (ttydisc_write_poll(tp) > 0)
652 			revents |= events & (POLLOUT|POLLWRNORM);
653 	}
654 
655 	if (revents == 0) {
656 		if (events & (POLLIN|POLLRDNORM))
657 			selrecord(td, &tp->t_inpoll);
658 		if (events & (POLLOUT|POLLWRNORM))
659 			selrecord(td, &tp->t_outpoll);
660 	}
661 
662 	tty_unlock(tp);
663 
664 	return (revents);
665 }
666 
667 static int
668 ttydev_mmap(struct cdev *dev, vm_ooffset_t offset, vm_paddr_t *paddr,
669     int nprot, vm_memattr_t *memattr)
670 {
671 	struct tty *tp = dev->si_drv1;
672 	int error;
673 
674 	/* Handle mmap() through the driver. */
675 
676 	error = ttydev_enter(tp);
677 	if (error)
678 		return (-1);
679 	error = ttydevsw_mmap(tp, offset, paddr, nprot, memattr);
680 	tty_unlock(tp);
681 
682 	return (error);
683 }
684 
685 /*
686  * kqueue support.
687  */
688 
689 static void
690 tty_kqops_read_detach(struct knote *kn)
691 {
692 	struct tty *tp = kn->kn_hook;
693 
694 	knlist_remove(&tp->t_inpoll.si_note, kn, 0);
695 }
696 
697 static int
698 tty_kqops_read_event(struct knote *kn, long hint __unused)
699 {
700 	struct tty *tp = kn->kn_hook;
701 
702 	tty_lock_assert(tp, MA_OWNED);
703 
704 	if (tty_gone(tp) || tp->t_flags & TF_ZOMBIE) {
705 		kn->kn_flags |= EV_EOF;
706 		return (1);
707 	} else {
708 		kn->kn_data = ttydisc_read_poll(tp);
709 		return (kn->kn_data > 0);
710 	}
711 }
712 
713 static void
714 tty_kqops_write_detach(struct knote *kn)
715 {
716 	struct tty *tp = kn->kn_hook;
717 
718 	knlist_remove(&tp->t_outpoll.si_note, kn, 0);
719 }
720 
721 static int
722 tty_kqops_write_event(struct knote *kn, long hint __unused)
723 {
724 	struct tty *tp = kn->kn_hook;
725 
726 	tty_lock_assert(tp, MA_OWNED);
727 
728 	if (tty_gone(tp)) {
729 		kn->kn_flags |= EV_EOF;
730 		return (1);
731 	} else {
732 		kn->kn_data = ttydisc_write_poll(tp);
733 		return (kn->kn_data > 0);
734 	}
735 }
736 
737 static struct filterops tty_kqops_read = {
738 	.f_isfd = 1,
739 	.f_detach = tty_kqops_read_detach,
740 	.f_event = tty_kqops_read_event,
741 };
742 
743 static struct filterops tty_kqops_write = {
744 	.f_isfd = 1,
745 	.f_detach = tty_kqops_write_detach,
746 	.f_event = tty_kqops_write_event,
747 };
748 
749 static int
750 ttydev_kqfilter(struct cdev *dev, struct knote *kn)
751 {
752 	struct tty *tp = dev->si_drv1;
753 	int error;
754 
755 	error = ttydev_enter(tp);
756 	if (error)
757 		return (error);
758 
759 	switch (kn->kn_filter) {
760 	case EVFILT_READ:
761 		kn->kn_hook = tp;
762 		kn->kn_fop = &tty_kqops_read;
763 		knlist_add(&tp->t_inpoll.si_note, kn, 1);
764 		break;
765 	case EVFILT_WRITE:
766 		kn->kn_hook = tp;
767 		kn->kn_fop = &tty_kqops_write;
768 		knlist_add(&tp->t_outpoll.si_note, kn, 1);
769 		break;
770 	default:
771 		error = EINVAL;
772 		break;
773 	}
774 
775 	tty_unlock(tp);
776 	return (error);
777 }
778 
779 static struct cdevsw ttydev_cdevsw = {
780 	.d_version	= D_VERSION,
781 	.d_open		= ttydev_open,
782 	.d_close	= ttydev_close,
783 	.d_read		= ttydev_read,
784 	.d_write	= ttydev_write,
785 	.d_ioctl	= ttydev_ioctl,
786 	.d_kqfilter	= ttydev_kqfilter,
787 	.d_poll		= ttydev_poll,
788 	.d_mmap		= ttydev_mmap,
789 	.d_name		= "ttydev",
790 	.d_flags	= D_TTY,
791 };
792 
793 /*
794  * Init/lock-state devices
795  */
796 
797 static int
798 ttyil_open(struct cdev *dev, int oflags __unused, int devtype __unused,
799     struct thread *td)
800 {
801 	struct tty *tp;
802 	int error;
803 
804 	tp = dev->si_drv1;
805 	error = 0;
806 	tty_lock(tp);
807 	if (tty_gone(tp))
808 		error = ENODEV;
809 	tty_unlock(tp);
810 
811 	return (error);
812 }
813 
814 static int
815 ttyil_close(struct cdev *dev __unused, int flag __unused, int mode __unused,
816     struct thread *td __unused)
817 {
818 
819 	return (0);
820 }
821 
822 static int
823 ttyil_rdwr(struct cdev *dev __unused, struct uio *uio __unused,
824     int ioflag __unused)
825 {
826 
827 	return (ENODEV);
828 }
829 
830 static int
831 ttyil_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int fflag,
832     struct thread *td)
833 {
834 	struct tty *tp = dev->si_drv1;
835 	int error;
836 
837 	tty_lock(tp);
838 	if (tty_gone(tp)) {
839 		error = ENODEV;
840 		goto done;
841 	}
842 
843 	error = ttydevsw_cioctl(tp, dev2unit(dev), cmd, data, td);
844 	if (error != ENOIOCTL)
845 		goto done;
846 	error = 0;
847 
848 	switch (cmd) {
849 	case TIOCGETA:
850 		/* Obtain terminal flags through tcgetattr(). */
851 		*(struct termios*)data = *(struct termios*)dev->si_drv2;
852 		break;
853 	case TIOCSETA:
854 		/* Set terminal flags through tcsetattr(). */
855 		error = priv_check(td, PRIV_TTY_SETA);
856 		if (error)
857 			break;
858 		*(struct termios*)dev->si_drv2 = *(struct termios*)data;
859 		break;
860 	case TIOCGETD:
861 		*(int *)data = TTYDISC;
862 		break;
863 	case TIOCGWINSZ:
864 		bzero(data, sizeof(struct winsize));
865 		break;
866 	default:
867 		error = ENOTTY;
868 	}
869 
870 done:	tty_unlock(tp);
871 	return (error);
872 }
873 
874 static struct cdevsw ttyil_cdevsw = {
875 	.d_version	= D_VERSION,
876 	.d_open		= ttyil_open,
877 	.d_close	= ttyil_close,
878 	.d_read		= ttyil_rdwr,
879 	.d_write	= ttyil_rdwr,
880 	.d_ioctl	= ttyil_ioctl,
881 	.d_name		= "ttyil",
882 	.d_flags	= D_TTY,
883 };
884 
885 static void
886 tty_init_termios(struct tty *tp)
887 {
888 	struct termios *t = &tp->t_termios_init_in;
889 
890 	t->c_cflag = TTYDEF_CFLAG;
891 	t->c_iflag = TTYDEF_IFLAG;
892 	t->c_lflag = TTYDEF_LFLAG;
893 	t->c_oflag = TTYDEF_OFLAG;
894 	t->c_ispeed = TTYDEF_SPEED;
895 	t->c_ospeed = TTYDEF_SPEED;
896 	memcpy(&t->c_cc, ttydefchars, sizeof ttydefchars);
897 
898 	tp->t_termios_init_out = *t;
899 }
900 
901 void
902 tty_init_console(struct tty *tp, speed_t s)
903 {
904 	struct termios *ti = &tp->t_termios_init_in;
905 	struct termios *to = &tp->t_termios_init_out;
906 
907 	if (s != 0) {
908 		ti->c_ispeed = ti->c_ospeed = s;
909 		to->c_ispeed = to->c_ospeed = s;
910 	}
911 
912 	ti->c_cflag |= CLOCAL;
913 	to->c_cflag |= CLOCAL;
914 }
915 
916 /*
917  * Standard device routine implementations, mostly meant for
918  * pseudo-terminal device drivers. When a driver creates a new terminal
919  * device class, missing routines are patched.
920  */
921 
922 static int
923 ttydevsw_defopen(struct tty *tp __unused)
924 {
925 
926 	return (0);
927 }
928 
929 static void
930 ttydevsw_defclose(struct tty *tp __unused)
931 {
932 
933 }
934 
935 static void
936 ttydevsw_defoutwakeup(struct tty *tp __unused)
937 {
938 
939 	panic("Terminal device has output, while not implemented");
940 }
941 
942 static void
943 ttydevsw_definwakeup(struct tty *tp __unused)
944 {
945 
946 }
947 
948 static int
949 ttydevsw_defioctl(struct tty *tp __unused, u_long cmd __unused,
950     caddr_t data __unused, struct thread *td __unused)
951 {
952 
953 	return (ENOIOCTL);
954 }
955 
956 static int
957 ttydevsw_defcioctl(struct tty *tp __unused, int unit __unused,
958     u_long cmd __unused, caddr_t data __unused, struct thread *td __unused)
959 {
960 
961 	return (ENOIOCTL);
962 }
963 
964 static int
965 ttydevsw_defparam(struct tty *tp __unused, struct termios *t)
966 {
967 
968 	/*
969 	 * Allow the baud rate to be adjusted for pseudo-devices, but at
970 	 * least restrict it to 115200 to prevent excessive buffer
971 	 * usage.  Also disallow 0, to prevent foot shooting.
972 	 */
973 	if (t->c_ispeed < B50)
974 		t->c_ispeed = B50;
975 	else if (t->c_ispeed > B115200)
976 		t->c_ispeed = B115200;
977 	if (t->c_ospeed < B50)
978 		t->c_ospeed = B50;
979 	else if (t->c_ospeed > B115200)
980 		t->c_ospeed = B115200;
981 	t->c_cflag |= CREAD;
982 
983 	return (0);
984 }
985 
986 static int
987 ttydevsw_defmodem(struct tty *tp __unused, int sigon __unused,
988     int sigoff __unused)
989 {
990 
991 	/* Simulate a carrier to make the TTY layer happy. */
992 	return (SER_DCD);
993 }
994 
995 static int
996 ttydevsw_defmmap(struct tty *tp __unused, vm_ooffset_t offset __unused,
997     vm_paddr_t *paddr __unused, int nprot __unused,
998     vm_memattr_t *memattr __unused)
999 {
1000 
1001 	return (-1);
1002 }
1003 
1004 static void
1005 ttydevsw_defpktnotify(struct tty *tp __unused, char event __unused)
1006 {
1007 
1008 }
1009 
1010 static void
1011 ttydevsw_deffree(void *softc __unused)
1012 {
1013 
1014 	panic("Terminal device freed without a free-handler");
1015 }
1016 
1017 static bool
1018 ttydevsw_defbusy(struct tty *tp __unused)
1019 {
1020 
1021 	return (FALSE);
1022 }
1023 
1024 /*
1025  * TTY allocation and deallocation. TTY devices can be deallocated when
1026  * the driver doesn't use it anymore, when the TTY isn't a session's
1027  * controlling TTY and when the device node isn't opened through devfs.
1028  */
1029 
1030 struct tty *
1031 tty_alloc(struct ttydevsw *tsw, void *sc)
1032 {
1033 
1034 	return (tty_alloc_mutex(tsw, sc, NULL));
1035 }
1036 
1037 struct tty *
1038 tty_alloc_mutex(struct ttydevsw *tsw, void *sc, struct mtx *mutex)
1039 {
1040 	struct tty *tp;
1041 
1042 	/* Make sure the driver defines all routines. */
1043 #define PATCH_FUNC(x) do {				\
1044 	if (tsw->tsw_ ## x == NULL)			\
1045 		tsw->tsw_ ## x = ttydevsw_def ## x;	\
1046 } while (0)
1047 	PATCH_FUNC(open);
1048 	PATCH_FUNC(close);
1049 	PATCH_FUNC(outwakeup);
1050 	PATCH_FUNC(inwakeup);
1051 	PATCH_FUNC(ioctl);
1052 	PATCH_FUNC(cioctl);
1053 	PATCH_FUNC(param);
1054 	PATCH_FUNC(modem);
1055 	PATCH_FUNC(mmap);
1056 	PATCH_FUNC(pktnotify);
1057 	PATCH_FUNC(free);
1058 	PATCH_FUNC(busy);
1059 #undef PATCH_FUNC
1060 
1061 	tp = malloc(sizeof(struct tty) + TTY_PRBUF_SIZE, M_TTY,
1062 	    M_WAITOK | M_ZERO);
1063 	tp->t_prbufsz = TTY_PRBUF_SIZE;
1064 	tp->t_devsw = tsw;
1065 	tp->t_devswsoftc = sc;
1066 	tp->t_flags = tsw->tsw_flags;
1067 	tp->t_drainwait = tty_drainwait;
1068 
1069 	tty_init_termios(tp);
1070 
1071 	cv_init(&tp->t_inwait, "ttyin");
1072 	cv_init(&tp->t_outwait, "ttyout");
1073 	cv_init(&tp->t_outserwait, "ttyosr");
1074 	cv_init(&tp->t_bgwait, "ttybg");
1075 	cv_init(&tp->t_dcdwait, "ttydcd");
1076 
1077 	/* Allow drivers to use a custom mutex to lock the TTY. */
1078 	if (mutex != NULL) {
1079 		tp->t_mtx = mutex;
1080 	} else {
1081 		tp->t_mtx = &tp->t_mtxobj;
1082 		mtx_init(&tp->t_mtxobj, "ttymtx", NULL, MTX_DEF);
1083 	}
1084 
1085 	knlist_init_mtx(&tp->t_inpoll.si_note, tp->t_mtx);
1086 	knlist_init_mtx(&tp->t_outpoll.si_note, tp->t_mtx);
1087 
1088 	return (tp);
1089 }
1090 
1091 static void
1092 tty_dealloc(void *arg)
1093 {
1094 	struct tty *tp = arg;
1095 
1096 	/*
1097 	 * ttyydev_leave() usually frees the i/o queues earlier, but it is
1098 	 * not always called between queue allocation and here.  The queues
1099 	 * may be allocated by ioctls on a pty control device without the
1100 	 * corresponding pty slave device ever being open, or after it is
1101 	 * closed.
1102 	 */
1103 	ttyinq_free(&tp->t_inq);
1104 	ttyoutq_free(&tp->t_outq);
1105 	seldrain(&tp->t_inpoll);
1106 	seldrain(&tp->t_outpoll);
1107 	knlist_destroy(&tp->t_inpoll.si_note);
1108 	knlist_destroy(&tp->t_outpoll.si_note);
1109 
1110 	cv_destroy(&tp->t_inwait);
1111 	cv_destroy(&tp->t_outwait);
1112 	cv_destroy(&tp->t_bgwait);
1113 	cv_destroy(&tp->t_dcdwait);
1114 	cv_destroy(&tp->t_outserwait);
1115 
1116 	if (tp->t_mtx == &tp->t_mtxobj)
1117 		mtx_destroy(&tp->t_mtxobj);
1118 	ttydevsw_free(tp);
1119 	free(tp, M_TTY);
1120 }
1121 
1122 static void
1123 tty_rel_free(struct tty *tp)
1124 {
1125 	struct cdev *dev;
1126 
1127 	tty_lock_assert(tp, MA_OWNED);
1128 
1129 #define	TF_ACTIVITY	(TF_GONE|TF_OPENED|TF_HOOK|TF_OPENCLOSE)
1130 	if (tp->t_sessioncnt != 0 || (tp->t_flags & TF_ACTIVITY) != TF_GONE) {
1131 		/* TTY is still in use. */
1132 		tty_unlock(tp);
1133 		return;
1134 	}
1135 
1136 	/* TTY can be deallocated. */
1137 	dev = tp->t_dev;
1138 	tp->t_dev = NULL;
1139 	tty_unlock(tp);
1140 
1141 	if (dev != NULL) {
1142 		sx_xlock(&tty_list_sx);
1143 		TAILQ_REMOVE(&tty_list, tp, t_list);
1144 		tty_list_count--;
1145 		sx_xunlock(&tty_list_sx);
1146 		destroy_dev_sched_cb(dev, tty_dealloc, tp);
1147 	}
1148 }
1149 
1150 void
1151 tty_rel_pgrp(struct tty *tp, struct pgrp *pg)
1152 {
1153 
1154 	MPASS(tp->t_sessioncnt > 0);
1155 	tty_lock_assert(tp, MA_OWNED);
1156 
1157 	if (tp->t_pgrp == pg)
1158 		tp->t_pgrp = NULL;
1159 
1160 	tty_unlock(tp);
1161 }
1162 
1163 void
1164 tty_rel_sess(struct tty *tp, struct session *sess)
1165 {
1166 
1167 	MPASS(tp->t_sessioncnt > 0);
1168 
1169 	/* Current session has left. */
1170 	if (tp->t_session == sess) {
1171 		tp->t_session = NULL;
1172 		MPASS(tp->t_pgrp == NULL);
1173 	}
1174 	tp->t_sessioncnt--;
1175 	tty_rel_free(tp);
1176 }
1177 
1178 void
1179 tty_rel_gone(struct tty *tp)
1180 {
1181 
1182 	MPASS(!tty_gone(tp));
1183 
1184 	/* Simulate carrier removal. */
1185 	ttydisc_modem(tp, 0);
1186 
1187 	/* Wake up all blocked threads. */
1188 	tty_wakeup(tp, FREAD|FWRITE);
1189 	cv_broadcast(&tp->t_bgwait);
1190 	cv_broadcast(&tp->t_dcdwait);
1191 
1192 	tp->t_flags |= TF_GONE;
1193 	tty_rel_free(tp);
1194 }
1195 
1196 /*
1197  * Exposing information about current TTY's through sysctl
1198  */
1199 
1200 static void
1201 tty_to_xtty(struct tty *tp, struct xtty *xt)
1202 {
1203 
1204 	tty_lock_assert(tp, MA_OWNED);
1205 
1206 	xt->xt_size = sizeof(struct xtty);
1207 	xt->xt_insize = ttyinq_getsize(&tp->t_inq);
1208 	xt->xt_incc = ttyinq_bytescanonicalized(&tp->t_inq);
1209 	xt->xt_inlc = ttyinq_bytesline(&tp->t_inq);
1210 	xt->xt_inlow = tp->t_inlow;
1211 	xt->xt_outsize = ttyoutq_getsize(&tp->t_outq);
1212 	xt->xt_outcc = ttyoutq_bytesused(&tp->t_outq);
1213 	xt->xt_outlow = tp->t_outlow;
1214 	xt->xt_column = tp->t_column;
1215 	xt->xt_pgid = tp->t_pgrp ? tp->t_pgrp->pg_id : 0;
1216 	xt->xt_sid = tp->t_session ? tp->t_session->s_sid : 0;
1217 	xt->xt_flags = tp->t_flags;
1218 	xt->xt_dev = tp->t_dev ? dev2udev(tp->t_dev) : (uint32_t)NODEV;
1219 }
1220 
1221 static int
1222 sysctl_kern_ttys(SYSCTL_HANDLER_ARGS)
1223 {
1224 	unsigned long lsize;
1225 	struct xtty *xtlist, *xt;
1226 	struct tty *tp;
1227 	int error;
1228 
1229 	sx_slock(&tty_list_sx);
1230 	lsize = tty_list_count * sizeof(struct xtty);
1231 	if (lsize == 0) {
1232 		sx_sunlock(&tty_list_sx);
1233 		return (0);
1234 	}
1235 
1236 	xtlist = xt = malloc(lsize, M_TTY, M_WAITOK);
1237 
1238 	TAILQ_FOREACH(tp, &tty_list, t_list) {
1239 		tty_lock(tp);
1240 		tty_to_xtty(tp, xt);
1241 		tty_unlock(tp);
1242 		xt++;
1243 	}
1244 	sx_sunlock(&tty_list_sx);
1245 
1246 	error = SYSCTL_OUT(req, xtlist, lsize);
1247 	free(xtlist, M_TTY);
1248 	return (error);
1249 }
1250 
1251 SYSCTL_PROC(_kern, OID_AUTO, ttys, CTLTYPE_OPAQUE|CTLFLAG_RD|CTLFLAG_MPSAFE,
1252 	0, 0, sysctl_kern_ttys, "S,xtty", "List of TTYs");
1253 
1254 /*
1255  * Device node creation. Device has been set up, now we can expose it to
1256  * the user.
1257  */
1258 
1259 int
1260 tty_makedevf(struct tty *tp, struct ucred *cred, int flags,
1261     const char *fmt, ...)
1262 {
1263 	va_list ap;
1264 	struct make_dev_args args;
1265 	struct cdev *dev, *init, *lock, *cua, *cinit, *clock;
1266 	const char *prefix = "tty";
1267 	char name[SPECNAMELEN - 3]; /* for "tty" and "cua". */
1268 	uid_t uid;
1269 	gid_t gid;
1270 	mode_t mode;
1271 	int error;
1272 
1273 	/* Remove "tty" prefix from devices like PTY's. */
1274 	if (tp->t_flags & TF_NOPREFIX)
1275 		prefix = "";
1276 
1277 	va_start(ap, fmt);
1278 	vsnrprintf(name, sizeof name, 32, fmt, ap);
1279 	va_end(ap);
1280 
1281 	if (cred == NULL) {
1282 		/* System device. */
1283 		uid = UID_ROOT;
1284 		gid = GID_WHEEL;
1285 		mode = S_IRUSR|S_IWUSR;
1286 	} else {
1287 		/* User device. */
1288 		uid = cred->cr_ruid;
1289 		gid = GID_TTY;
1290 		mode = S_IRUSR|S_IWUSR|S_IWGRP;
1291 	}
1292 
1293 	flags = flags & TTYMK_CLONING ? MAKEDEV_REF : 0;
1294 	flags |= MAKEDEV_CHECKNAME;
1295 
1296 	/* Master call-in device. */
1297 	make_dev_args_init(&args);
1298 	args.mda_flags = flags;
1299 	args.mda_devsw = &ttydev_cdevsw;
1300 	args.mda_cr = cred;
1301 	args.mda_uid = uid;
1302 	args.mda_gid = gid;
1303 	args.mda_mode = mode;
1304 	args.mda_si_drv1 = tp;
1305 	error = make_dev_s(&args, &dev, "%s%s", prefix, name);
1306 	if (error != 0)
1307 		return (error);
1308 	tp->t_dev = dev;
1309 
1310 	init = lock = cua = cinit = clock = NULL;
1311 
1312 	/* Slave call-in devices. */
1313 	if (tp->t_flags & TF_INITLOCK) {
1314 		args.mda_devsw = &ttyil_cdevsw;
1315 		args.mda_unit = TTYUNIT_INIT;
1316 		args.mda_si_drv1 = tp;
1317 		args.mda_si_drv2 = &tp->t_termios_init_in;
1318 		error = make_dev_s(&args, &init, "%s%s.init", prefix, name);
1319 		if (error != 0)
1320 			goto fail;
1321 		dev_depends(dev, init);
1322 
1323 		args.mda_unit = TTYUNIT_LOCK;
1324 		args.mda_si_drv2 = &tp->t_termios_lock_in;
1325 		error = make_dev_s(&args, &lock, "%s%s.lock", prefix, name);
1326 		if (error != 0)
1327 			goto fail;
1328 		dev_depends(dev, lock);
1329 	}
1330 
1331 	/* Call-out devices. */
1332 	if (tp->t_flags & TF_CALLOUT) {
1333 		make_dev_args_init(&args);
1334 		args.mda_flags = flags;
1335 		args.mda_devsw = &ttydev_cdevsw;
1336 		args.mda_cr = cred;
1337 		args.mda_uid = UID_UUCP;
1338 		args.mda_gid = GID_DIALER;
1339 		args.mda_mode = 0660;
1340 		args.mda_unit = TTYUNIT_CALLOUT;
1341 		args.mda_si_drv1 = tp;
1342 		error = make_dev_s(&args, &cua, "cua%s", name);
1343 		if (error != 0)
1344 			goto fail;
1345 		dev_depends(dev, cua);
1346 
1347 		/* Slave call-out devices. */
1348 		if (tp->t_flags & TF_INITLOCK) {
1349 			args.mda_devsw = &ttyil_cdevsw;
1350 			args.mda_unit = TTYUNIT_CALLOUT | TTYUNIT_INIT;
1351 			args.mda_si_drv2 = &tp->t_termios_init_out;
1352 			error = make_dev_s(&args, &cinit, "cua%s.init", name);
1353 			if (error != 0)
1354 				goto fail;
1355 			dev_depends(dev, cinit);
1356 
1357 			args.mda_unit = TTYUNIT_CALLOUT | TTYUNIT_LOCK;
1358 			args.mda_si_drv2 = &tp->t_termios_lock_out;
1359 			error = make_dev_s(&args, &clock, "cua%s.lock", name);
1360 			if (error != 0)
1361 				goto fail;
1362 			dev_depends(dev, clock);
1363 		}
1364 	}
1365 
1366 	sx_xlock(&tty_list_sx);
1367 	TAILQ_INSERT_TAIL(&tty_list, tp, t_list);
1368 	tty_list_count++;
1369 	sx_xunlock(&tty_list_sx);
1370 
1371 	return (0);
1372 
1373 fail:
1374 	destroy_dev(dev);
1375 	if (init)
1376 		destroy_dev(init);
1377 	if (lock)
1378 		destroy_dev(lock);
1379 	if (cinit)
1380 		destroy_dev(cinit);
1381 	if (clock)
1382 		destroy_dev(clock);
1383 
1384 	return (error);
1385 }
1386 
1387 /*
1388  * Signalling processes.
1389  */
1390 
1391 void
1392 tty_signal_sessleader(struct tty *tp, int sig)
1393 {
1394 	struct proc *p;
1395 
1396 	tty_lock_assert(tp, MA_OWNED);
1397 	MPASS(sig >= 1 && sig < NSIG);
1398 
1399 	/* Make signals start output again. */
1400 	tp->t_flags &= ~TF_STOPPED;
1401 
1402 	if (tp->t_session != NULL && tp->t_session->s_leader != NULL) {
1403 		p = tp->t_session->s_leader;
1404 		PROC_LOCK(p);
1405 		kern_psignal(p, sig);
1406 		PROC_UNLOCK(p);
1407 	}
1408 }
1409 
1410 void
1411 tty_signal_pgrp(struct tty *tp, int sig)
1412 {
1413 	ksiginfo_t ksi;
1414 
1415 	tty_lock_assert(tp, MA_OWNED);
1416 	MPASS(sig >= 1 && sig < NSIG);
1417 
1418 	/* Make signals start output again. */
1419 	tp->t_flags &= ~TF_STOPPED;
1420 
1421 	if (sig == SIGINFO && !(tp->t_termios.c_lflag & NOKERNINFO))
1422 		tty_info(tp);
1423 	if (tp->t_pgrp != NULL) {
1424 		ksiginfo_init(&ksi);
1425 		ksi.ksi_signo = sig;
1426 		ksi.ksi_code = SI_KERNEL;
1427 		PGRP_LOCK(tp->t_pgrp);
1428 		pgsignal(tp->t_pgrp, sig, 1, &ksi);
1429 		PGRP_UNLOCK(tp->t_pgrp);
1430 	}
1431 }
1432 
1433 void
1434 tty_wakeup(struct tty *tp, int flags)
1435 {
1436 
1437 	if (tp->t_flags & TF_ASYNC && tp->t_sigio != NULL)
1438 		pgsigio(&tp->t_sigio, SIGIO, (tp->t_session != NULL));
1439 
1440 	if (flags & FWRITE) {
1441 		cv_broadcast(&tp->t_outwait);
1442 		selwakeup(&tp->t_outpoll);
1443 		KNOTE_LOCKED(&tp->t_outpoll.si_note, 0);
1444 	}
1445 	if (flags & FREAD) {
1446 		cv_broadcast(&tp->t_inwait);
1447 		selwakeup(&tp->t_inpoll);
1448 		KNOTE_LOCKED(&tp->t_inpoll.si_note, 0);
1449 	}
1450 }
1451 
1452 int
1453 tty_wait(struct tty *tp, struct cv *cv)
1454 {
1455 	int error;
1456 	int revokecnt = tp->t_revokecnt;
1457 
1458 	tty_lock_assert(tp, MA_OWNED|MA_NOTRECURSED);
1459 	MPASS(!tty_gone(tp));
1460 
1461 	error = cv_wait_sig(cv, tp->t_mtx);
1462 
1463 	/* Bail out when the device slipped away. */
1464 	if (tty_gone(tp))
1465 		return (ENXIO);
1466 
1467 	/* Restart the system call when we may have been revoked. */
1468 	if (tp->t_revokecnt != revokecnt)
1469 		return (ERESTART);
1470 
1471 	return (error);
1472 }
1473 
1474 int
1475 tty_timedwait(struct tty *tp, struct cv *cv, int hz)
1476 {
1477 	int error;
1478 	int revokecnt = tp->t_revokecnt;
1479 
1480 	tty_lock_assert(tp, MA_OWNED|MA_NOTRECURSED);
1481 	MPASS(!tty_gone(tp));
1482 
1483 	error = cv_timedwait_sig(cv, tp->t_mtx, hz);
1484 
1485 	/* Bail out when the device slipped away. */
1486 	if (tty_gone(tp))
1487 		return (ENXIO);
1488 
1489 	/* Restart the system call when we may have been revoked. */
1490 	if (tp->t_revokecnt != revokecnt)
1491 		return (ERESTART);
1492 
1493 	return (error);
1494 }
1495 
1496 void
1497 tty_flush(struct tty *tp, int flags)
1498 {
1499 
1500 	if (flags & FWRITE) {
1501 		tp->t_flags &= ~TF_HIWAT_OUT;
1502 		ttyoutq_flush(&tp->t_outq);
1503 		tty_wakeup(tp, FWRITE);
1504 		if (!tty_gone(tp)) {
1505 			ttydevsw_outwakeup(tp);
1506 			ttydevsw_pktnotify(tp, TIOCPKT_FLUSHWRITE);
1507 		}
1508 	}
1509 	if (flags & FREAD) {
1510 		tty_hiwat_in_unblock(tp);
1511 		ttyinq_flush(&tp->t_inq);
1512 		tty_wakeup(tp, FREAD);
1513 		if (!tty_gone(tp)) {
1514 			ttydevsw_inwakeup(tp);
1515 			ttydevsw_pktnotify(tp, TIOCPKT_FLUSHREAD);
1516 		}
1517 	}
1518 }
1519 
1520 void
1521 tty_set_winsize(struct tty *tp, const struct winsize *wsz)
1522 {
1523 
1524 	if (memcmp(&tp->t_winsize, wsz, sizeof(*wsz)) == 0)
1525 		return;
1526 	tp->t_winsize = *wsz;
1527 	tty_signal_pgrp(tp, SIGWINCH);
1528 }
1529 
1530 static int
1531 tty_generic_ioctl(struct tty *tp, u_long cmd, void *data, int fflag,
1532     struct thread *td)
1533 {
1534 	int error;
1535 
1536 	switch (cmd) {
1537 	/*
1538 	 * Modem commands.
1539 	 * The SER_* and TIOCM_* flags are the same, but one bit
1540 	 * shifted. I don't know why.
1541 	 */
1542 	case TIOCSDTR:
1543 		ttydevsw_modem(tp, SER_DTR, 0);
1544 		return (0);
1545 	case TIOCCDTR:
1546 		ttydevsw_modem(tp, 0, SER_DTR);
1547 		return (0);
1548 	case TIOCMSET: {
1549 		int bits = *(int *)data;
1550 		ttydevsw_modem(tp,
1551 		    (bits & (TIOCM_DTR | TIOCM_RTS)) >> 1,
1552 		    ((~bits) & (TIOCM_DTR | TIOCM_RTS)) >> 1);
1553 		return (0);
1554 	}
1555 	case TIOCMBIS: {
1556 		int bits = *(int *)data;
1557 		ttydevsw_modem(tp, (bits & (TIOCM_DTR | TIOCM_RTS)) >> 1, 0);
1558 		return (0);
1559 	}
1560 	case TIOCMBIC: {
1561 		int bits = *(int *)data;
1562 		ttydevsw_modem(tp, 0, (bits & (TIOCM_DTR | TIOCM_RTS)) >> 1);
1563 		return (0);
1564 	}
1565 	case TIOCMGET:
1566 		*(int *)data = TIOCM_LE + (ttydevsw_modem(tp, 0, 0) << 1);
1567 		return (0);
1568 
1569 	case FIOASYNC:
1570 		if (*(int *)data)
1571 			tp->t_flags |= TF_ASYNC;
1572 		else
1573 			tp->t_flags &= ~TF_ASYNC;
1574 		return (0);
1575 	case FIONBIO:
1576 		/* This device supports non-blocking operation. */
1577 		return (0);
1578 	case FIONREAD:
1579 		*(int *)data = ttyinq_bytescanonicalized(&tp->t_inq);
1580 		return (0);
1581 	case FIONWRITE:
1582 	case TIOCOUTQ:
1583 		*(int *)data = ttyoutq_bytesused(&tp->t_outq);
1584 		return (0);
1585 	case FIOSETOWN:
1586 		if (tp->t_session != NULL && !tty_is_ctty(tp, td->td_proc))
1587 			/* Not allowed to set ownership. */
1588 			return (ENOTTY);
1589 
1590 		/* Temporarily unlock the TTY to set ownership. */
1591 		tty_unlock(tp);
1592 		error = fsetown(*(int *)data, &tp->t_sigio);
1593 		tty_lock(tp);
1594 		return (error);
1595 	case FIOGETOWN:
1596 		if (tp->t_session != NULL && !tty_is_ctty(tp, td->td_proc))
1597 			/* Not allowed to set ownership. */
1598 			return (ENOTTY);
1599 
1600 		/* Get ownership. */
1601 		*(int *)data = fgetown(&tp->t_sigio);
1602 		return (0);
1603 	case TIOCGETA:
1604 		/* Obtain terminal flags through tcgetattr(). */
1605 		*(struct termios*)data = tp->t_termios;
1606 		return (0);
1607 	case TIOCSETA:
1608 	case TIOCSETAW:
1609 	case TIOCSETAF: {
1610 		struct termios *t = data;
1611 
1612 		/*
1613 		 * Who makes up these funny rules? According to POSIX,
1614 		 * input baud rate is set equal to the output baud rate
1615 		 * when zero.
1616 		 */
1617 		if (t->c_ispeed == 0)
1618 			t->c_ispeed = t->c_ospeed;
1619 
1620 		/* Discard any unsupported bits. */
1621 		t->c_iflag &= TTYSUP_IFLAG;
1622 		t->c_oflag &= TTYSUP_OFLAG;
1623 		t->c_lflag &= TTYSUP_LFLAG;
1624 		t->c_cflag &= TTYSUP_CFLAG;
1625 
1626 		/* Set terminal flags through tcsetattr(). */
1627 		if (cmd == TIOCSETAW || cmd == TIOCSETAF) {
1628 			error = tty_drain(tp, 0);
1629 			if (error)
1630 				return (error);
1631 			if (cmd == TIOCSETAF)
1632 				tty_flush(tp, FREAD);
1633 		}
1634 
1635 		/*
1636 		 * Only call param() when the flags really change.
1637 		 */
1638 		if ((t->c_cflag & CIGNORE) == 0 &&
1639 		    (tp->t_termios.c_cflag != t->c_cflag ||
1640 		    ((tp->t_termios.c_iflag ^ t->c_iflag) &
1641 		    (IXON|IXOFF|IXANY)) ||
1642 		    tp->t_termios.c_ispeed != t->c_ispeed ||
1643 		    tp->t_termios.c_ospeed != t->c_ospeed)) {
1644 			error = ttydevsw_param(tp, t);
1645 			if (error)
1646 				return (error);
1647 
1648 			/* XXX: CLOCAL? */
1649 
1650 			tp->t_termios.c_cflag = t->c_cflag & ~CIGNORE;
1651 			tp->t_termios.c_ispeed = t->c_ispeed;
1652 			tp->t_termios.c_ospeed = t->c_ospeed;
1653 
1654 			/* Baud rate has changed - update watermarks. */
1655 			error = tty_watermarks(tp);
1656 			if (error)
1657 				return (error);
1658 		}
1659 
1660 		/* Copy new non-device driver parameters. */
1661 		tp->t_termios.c_iflag = t->c_iflag;
1662 		tp->t_termios.c_oflag = t->c_oflag;
1663 		tp->t_termios.c_lflag = t->c_lflag;
1664 		memcpy(&tp->t_termios.c_cc, t->c_cc, sizeof t->c_cc);
1665 
1666 		ttydisc_optimize(tp);
1667 
1668 		if ((t->c_lflag & ICANON) == 0) {
1669 			/*
1670 			 * When in non-canonical mode, wake up all
1671 			 * readers. Canonicalize any partial input. VMIN
1672 			 * and VTIME could also be adjusted.
1673 			 */
1674 			ttyinq_canonicalize(&tp->t_inq);
1675 			tty_wakeup(tp, FREAD);
1676 		}
1677 
1678 		/*
1679 		 * For packet mode: notify the PTY consumer that VSTOP
1680 		 * and VSTART may have been changed.
1681 		 */
1682 		if (tp->t_termios.c_iflag & IXON &&
1683 		    tp->t_termios.c_cc[VSTOP] == CTRL('S') &&
1684 		    tp->t_termios.c_cc[VSTART] == CTRL('Q'))
1685 			ttydevsw_pktnotify(tp, TIOCPKT_DOSTOP);
1686 		else
1687 			ttydevsw_pktnotify(tp, TIOCPKT_NOSTOP);
1688 		return (0);
1689 	}
1690 	case TIOCGETD:
1691 		/* For compatibility - we only support TTYDISC. */
1692 		*(int *)data = TTYDISC;
1693 		return (0);
1694 	case TIOCGPGRP:
1695 		if (!tty_is_ctty(tp, td->td_proc))
1696 			return (ENOTTY);
1697 
1698 		if (tp->t_pgrp != NULL)
1699 			*(int *)data = tp->t_pgrp->pg_id;
1700 		else
1701 			*(int *)data = NO_PID;
1702 		return (0);
1703 	case TIOCGSID:
1704 		if (!tty_is_ctty(tp, td->td_proc))
1705 			return (ENOTTY);
1706 
1707 		MPASS(tp->t_session);
1708 		*(int *)data = tp->t_session->s_sid;
1709 		return (0);
1710 	case TIOCSCTTY: {
1711 		struct proc *p = td->td_proc;
1712 
1713 		/* XXX: This looks awful. */
1714 		tty_unlock(tp);
1715 		sx_xlock(&proctree_lock);
1716 		tty_lock(tp);
1717 
1718 		if (!SESS_LEADER(p)) {
1719 			/* Only the session leader may do this. */
1720 			sx_xunlock(&proctree_lock);
1721 			return (EPERM);
1722 		}
1723 
1724 		if (tp->t_session != NULL && tp->t_session == p->p_session) {
1725 			/* This is already our controlling TTY. */
1726 			sx_xunlock(&proctree_lock);
1727 			return (0);
1728 		}
1729 
1730 		if (p->p_session->s_ttyp != NULL ||
1731 		    (tp->t_session != NULL && tp->t_session->s_ttyvp != NULL &&
1732 		    tp->t_session->s_ttyvp->v_type != VBAD)) {
1733 			/*
1734 			 * There is already a relation between a TTY and
1735 			 * a session, or the caller is not the session
1736 			 * leader.
1737 			 *
1738 			 * Allow the TTY to be stolen when the vnode is
1739 			 * invalid, but the reference to the TTY is
1740 			 * still active.  This allows immediate reuse of
1741 			 * TTYs of which the session leader has been
1742 			 * killed or the TTY revoked.
1743 			 */
1744 			sx_xunlock(&proctree_lock);
1745 			return (EPERM);
1746 		}
1747 
1748 		/* Connect the session to the TTY. */
1749 		tp->t_session = p->p_session;
1750 		tp->t_session->s_ttyp = tp;
1751 		tp->t_sessioncnt++;
1752 		sx_xunlock(&proctree_lock);
1753 
1754 		/* Assign foreground process group. */
1755 		tp->t_pgrp = p->p_pgrp;
1756 		PROC_LOCK(p);
1757 		p->p_flag |= P_CONTROLT;
1758 		PROC_UNLOCK(p);
1759 
1760 		return (0);
1761 	}
1762 	case TIOCSPGRP: {
1763 		struct pgrp *pg;
1764 
1765 		/*
1766 		 * XXX: Temporarily unlock the TTY to locate the process
1767 		 * group. This code would be lot nicer if we would ever
1768 		 * decompose proctree_lock.
1769 		 */
1770 		tty_unlock(tp);
1771 		sx_slock(&proctree_lock);
1772 		pg = pgfind(*(int *)data);
1773 		if (pg != NULL)
1774 			PGRP_UNLOCK(pg);
1775 		if (pg == NULL || pg->pg_session != td->td_proc->p_session) {
1776 			sx_sunlock(&proctree_lock);
1777 			tty_lock(tp);
1778 			return (EPERM);
1779 		}
1780 		tty_lock(tp);
1781 
1782 		/*
1783 		 * Determine if this TTY is the controlling TTY after
1784 		 * relocking the TTY.
1785 		 */
1786 		if (!tty_is_ctty(tp, td->td_proc)) {
1787 			sx_sunlock(&proctree_lock);
1788 			return (ENOTTY);
1789 		}
1790 		tp->t_pgrp = pg;
1791 		sx_sunlock(&proctree_lock);
1792 
1793 		/* Wake up the background process groups. */
1794 		cv_broadcast(&tp->t_bgwait);
1795 		return (0);
1796 	}
1797 	case TIOCFLUSH: {
1798 		int flags = *(int *)data;
1799 
1800 		if (flags == 0)
1801 			flags = (FREAD|FWRITE);
1802 		else
1803 			flags &= (FREAD|FWRITE);
1804 		tty_flush(tp, flags);
1805 		return (0);
1806 	}
1807 	case TIOCDRAIN:
1808 		/* Drain TTY output. */
1809 		return tty_drain(tp, 0);
1810 	case TIOCGDRAINWAIT:
1811 		*(int *)data = tp->t_drainwait;
1812 		return (0);
1813 	case TIOCSDRAINWAIT:
1814 		error = priv_check(td, PRIV_TTY_DRAINWAIT);
1815 		if (error == 0)
1816 			tp->t_drainwait = *(int *)data;
1817 		return (error);
1818 	case TIOCCONS:
1819 		/* Set terminal as console TTY. */
1820 		if (*(int *)data) {
1821 			error = priv_check(td, PRIV_TTY_CONSOLE);
1822 			if (error)
1823 				return (error);
1824 
1825 			/*
1826 			 * XXX: constty should really need to be locked!
1827 			 * XXX: allow disconnected constty's to be stolen!
1828 			 */
1829 
1830 			if (constty == tp)
1831 				return (0);
1832 			if (constty != NULL)
1833 				return (EBUSY);
1834 
1835 			tty_unlock(tp);
1836 			constty_set(tp);
1837 			tty_lock(tp);
1838 		} else if (constty == tp) {
1839 			constty_clear();
1840 		}
1841 		return (0);
1842 	case TIOCGWINSZ:
1843 		/* Obtain window size. */
1844 		*(struct winsize*)data = tp->t_winsize;
1845 		return (0);
1846 	case TIOCSWINSZ:
1847 		/* Set window size. */
1848 		tty_set_winsize(tp, data);
1849 		return (0);
1850 	case TIOCEXCL:
1851 		tp->t_flags |= TF_EXCLUDE;
1852 		return (0);
1853 	case TIOCNXCL:
1854 		tp->t_flags &= ~TF_EXCLUDE;
1855 		return (0);
1856 	case TIOCSTOP:
1857 		tp->t_flags |= TF_STOPPED;
1858 		ttydevsw_pktnotify(tp, TIOCPKT_STOP);
1859 		return (0);
1860 	case TIOCSTART:
1861 		tp->t_flags &= ~TF_STOPPED;
1862 		ttydevsw_outwakeup(tp);
1863 		ttydevsw_pktnotify(tp, TIOCPKT_START);
1864 		return (0);
1865 	case TIOCSTAT:
1866 		tty_info(tp);
1867 		return (0);
1868 	case TIOCSTI:
1869 		if ((fflag & FREAD) == 0 && priv_check(td, PRIV_TTY_STI))
1870 			return (EPERM);
1871 		if (!tty_is_ctty(tp, td->td_proc) &&
1872 		    priv_check(td, PRIV_TTY_STI))
1873 			return (EACCES);
1874 		ttydisc_rint(tp, *(char *)data, 0);
1875 		ttydisc_rint_done(tp);
1876 		return (0);
1877 	}
1878 
1879 #ifdef COMPAT_43TTY
1880 	return tty_ioctl_compat(tp, cmd, data, fflag, td);
1881 #else /* !COMPAT_43TTY */
1882 	return (ENOIOCTL);
1883 #endif /* COMPAT_43TTY */
1884 }
1885 
1886 int
1887 tty_ioctl(struct tty *tp, u_long cmd, void *data, int fflag, struct thread *td)
1888 {
1889 	int error;
1890 
1891 	tty_lock_assert(tp, MA_OWNED);
1892 
1893 	if (tty_gone(tp))
1894 		return (ENXIO);
1895 
1896 	error = ttydevsw_ioctl(tp, cmd, data, td);
1897 	if (error == ENOIOCTL)
1898 		error = tty_generic_ioctl(tp, cmd, data, fflag, td);
1899 
1900 	return (error);
1901 }
1902 
1903 dev_t
1904 tty_udev(struct tty *tp)
1905 {
1906 
1907 	if (tp->t_dev)
1908 		return (dev2udev(tp->t_dev));
1909 	else
1910 		return (NODEV);
1911 }
1912 
1913 int
1914 tty_checkoutq(struct tty *tp)
1915 {
1916 
1917 	/* 256 bytes should be enough to print a log message. */
1918 	return (ttyoutq_bytesleft(&tp->t_outq) >= 256);
1919 }
1920 
1921 void
1922 tty_hiwat_in_block(struct tty *tp)
1923 {
1924 
1925 	if ((tp->t_flags & TF_HIWAT_IN) == 0 &&
1926 	    tp->t_termios.c_iflag & IXOFF &&
1927 	    tp->t_termios.c_cc[VSTOP] != _POSIX_VDISABLE) {
1928 		/*
1929 		 * Input flow control. Only enter the high watermark when we
1930 		 * can successfully store the VSTOP character.
1931 		 */
1932 		if (ttyoutq_write_nofrag(&tp->t_outq,
1933 		    &tp->t_termios.c_cc[VSTOP], 1) == 0)
1934 			tp->t_flags |= TF_HIWAT_IN;
1935 	} else {
1936 		/* No input flow control. */
1937 		tp->t_flags |= TF_HIWAT_IN;
1938 	}
1939 }
1940 
1941 void
1942 tty_hiwat_in_unblock(struct tty *tp)
1943 {
1944 
1945 	if (tp->t_flags & TF_HIWAT_IN &&
1946 	    tp->t_termios.c_iflag & IXOFF &&
1947 	    tp->t_termios.c_cc[VSTART] != _POSIX_VDISABLE) {
1948 		/*
1949 		 * Input flow control. Only leave the high watermark when we
1950 		 * can successfully store the VSTART character.
1951 		 */
1952 		if (ttyoutq_write_nofrag(&tp->t_outq,
1953 		    &tp->t_termios.c_cc[VSTART], 1) == 0)
1954 			tp->t_flags &= ~TF_HIWAT_IN;
1955 	} else {
1956 		/* No input flow control. */
1957 		tp->t_flags &= ~TF_HIWAT_IN;
1958 	}
1959 
1960 	if (!tty_gone(tp))
1961 		ttydevsw_inwakeup(tp);
1962 }
1963 
1964 /*
1965  * TTY hooks interface.
1966  */
1967 
1968 static int
1969 ttyhook_defrint(struct tty *tp, char c, int flags)
1970 {
1971 
1972 	if (ttyhook_rint_bypass(tp, &c, 1) != 1)
1973 		return (-1);
1974 
1975 	return (0);
1976 }
1977 
1978 int
1979 ttyhook_register(struct tty **rtp, struct proc *p, int fd, struct ttyhook *th,
1980     void *softc)
1981 {
1982 	struct tty *tp;
1983 	struct file *fp;
1984 	struct cdev *dev;
1985 	struct cdevsw *cdp;
1986 	struct filedesc *fdp;
1987 	cap_rights_t rights;
1988 	int error, ref;
1989 
1990 	/* Validate the file descriptor. */
1991 	fdp = p->p_fd;
1992 	error = fget_unlocked(fdp, fd, cap_rights_init(&rights, CAP_TTYHOOK),
1993 	    &fp, NULL);
1994 	if (error != 0)
1995 		return (error);
1996 	if (fp->f_ops == &badfileops) {
1997 		error = EBADF;
1998 		goto done1;
1999 	}
2000 
2001 	/*
2002 	 * Make sure the vnode is bound to a character device.
2003 	 * Unlocked check for the vnode type is ok there, because we
2004 	 * only shall prevent calling devvn_refthread on the file that
2005 	 * never has been opened over a character device.
2006 	 */
2007 	if (fp->f_type != DTYPE_VNODE || fp->f_vnode->v_type != VCHR) {
2008 		error = EINVAL;
2009 		goto done1;
2010 	}
2011 
2012 	/* Make sure it is a TTY. */
2013 	cdp = devvn_refthread(fp->f_vnode, &dev, &ref);
2014 	if (cdp == NULL) {
2015 		error = ENXIO;
2016 		goto done1;
2017 	}
2018 	if (dev != fp->f_data) {
2019 		error = ENXIO;
2020 		goto done2;
2021 	}
2022 	if (cdp != &ttydev_cdevsw) {
2023 		error = ENOTTY;
2024 		goto done2;
2025 	}
2026 	tp = dev->si_drv1;
2027 
2028 	/* Try to attach the hook to the TTY. */
2029 	error = EBUSY;
2030 	tty_lock(tp);
2031 	MPASS((tp->t_hook == NULL) == ((tp->t_flags & TF_HOOK) == 0));
2032 	if (tp->t_flags & TF_HOOK)
2033 		goto done3;
2034 
2035 	tp->t_flags |= TF_HOOK;
2036 	tp->t_hook = th;
2037 	tp->t_hooksoftc = softc;
2038 	*rtp = tp;
2039 	error = 0;
2040 
2041 	/* Maybe we can switch into bypass mode now. */
2042 	ttydisc_optimize(tp);
2043 
2044 	/* Silently convert rint() calls to rint_bypass() when possible. */
2045 	if (!ttyhook_hashook(tp, rint) && ttyhook_hashook(tp, rint_bypass))
2046 		th->th_rint = ttyhook_defrint;
2047 
2048 done3:	tty_unlock(tp);
2049 done2:	dev_relthread(dev, ref);
2050 done1:	fdrop(fp, curthread);
2051 	return (error);
2052 }
2053 
2054 void
2055 ttyhook_unregister(struct tty *tp)
2056 {
2057 
2058 	tty_lock_assert(tp, MA_OWNED);
2059 	MPASS(tp->t_flags & TF_HOOK);
2060 
2061 	/* Disconnect the hook. */
2062 	tp->t_flags &= ~TF_HOOK;
2063 	tp->t_hook = NULL;
2064 
2065 	/* Maybe we need to leave bypass mode. */
2066 	ttydisc_optimize(tp);
2067 
2068 	/* Maybe deallocate the TTY as well. */
2069 	tty_rel_free(tp);
2070 }
2071 
2072 /*
2073  * /dev/console handling.
2074  */
2075 
2076 static int
2077 ttyconsdev_open(struct cdev *dev, int oflags, int devtype, struct thread *td)
2078 {
2079 	struct tty *tp;
2080 
2081 	/* System has no console device. */
2082 	if (dev_console_filename == NULL)
2083 		return (ENXIO);
2084 
2085 	/* Look up corresponding TTY by device name. */
2086 	sx_slock(&tty_list_sx);
2087 	TAILQ_FOREACH(tp, &tty_list, t_list) {
2088 		if (strcmp(dev_console_filename, tty_devname(tp)) == 0) {
2089 			dev_console->si_drv1 = tp;
2090 			break;
2091 		}
2092 	}
2093 	sx_sunlock(&tty_list_sx);
2094 
2095 	/* System console has no TTY associated. */
2096 	if (dev_console->si_drv1 == NULL)
2097 		return (ENXIO);
2098 
2099 	return (ttydev_open(dev, oflags, devtype, td));
2100 }
2101 
2102 static int
2103 ttyconsdev_write(struct cdev *dev, struct uio *uio, int ioflag)
2104 {
2105 
2106 	log_console(uio);
2107 
2108 	return (ttydev_write(dev, uio, ioflag));
2109 }
2110 
2111 /*
2112  * /dev/console is a little different than normal TTY's.  When opened,
2113  * it determines which TTY to use.  When data gets written to it, it
2114  * will be logged in the kernel message buffer.
2115  */
2116 static struct cdevsw ttyconsdev_cdevsw = {
2117 	.d_version	= D_VERSION,
2118 	.d_open		= ttyconsdev_open,
2119 	.d_close	= ttydev_close,
2120 	.d_read		= ttydev_read,
2121 	.d_write	= ttyconsdev_write,
2122 	.d_ioctl	= ttydev_ioctl,
2123 	.d_kqfilter	= ttydev_kqfilter,
2124 	.d_poll		= ttydev_poll,
2125 	.d_mmap		= ttydev_mmap,
2126 	.d_name		= "ttyconsdev",
2127 	.d_flags	= D_TTY,
2128 };
2129 
2130 static void
2131 ttyconsdev_init(void *unused __unused)
2132 {
2133 
2134 	dev_console = make_dev_credf(MAKEDEV_ETERNAL, &ttyconsdev_cdevsw, 0,
2135 	    NULL, UID_ROOT, GID_WHEEL, 0600, "console");
2136 }
2137 
2138 SYSINIT(tty, SI_SUB_DRIVERS, SI_ORDER_FIRST, ttyconsdev_init, NULL);
2139 
2140 void
2141 ttyconsdev_select(const char *name)
2142 {
2143 
2144 	dev_console_filename = name;
2145 }
2146 
2147 /*
2148  * Debugging routines.
2149  */
2150 
2151 #include "opt_ddb.h"
2152 #ifdef DDB
2153 #include <ddb/ddb.h>
2154 #include <ddb/db_sym.h>
2155 
2156 static const struct {
2157 	int flag;
2158 	char val;
2159 } ttystates[] = {
2160 #if 0
2161 	{ TF_NOPREFIX,		'N' },
2162 #endif
2163 	{ TF_INITLOCK,		'I' },
2164 	{ TF_CALLOUT,		'C' },
2165 
2166 	/* Keep these together -> 'Oi' and 'Oo'. */
2167 	{ TF_OPENED,		'O' },
2168 	{ TF_OPENED_IN,		'i' },
2169 	{ TF_OPENED_OUT,	'o' },
2170 	{ TF_OPENED_CONS,	'c' },
2171 
2172 	{ TF_GONE,		'G' },
2173 	{ TF_OPENCLOSE,		'B' },
2174 	{ TF_ASYNC,		'Y' },
2175 	{ TF_LITERAL,		'L' },
2176 
2177 	/* Keep these together -> 'Hi' and 'Ho'. */
2178 	{ TF_HIWAT,		'H' },
2179 	{ TF_HIWAT_IN,		'i' },
2180 	{ TF_HIWAT_OUT,		'o' },
2181 
2182 	{ TF_STOPPED,		'S' },
2183 	{ TF_EXCLUDE,		'X' },
2184 	{ TF_BYPASS,		'l' },
2185 	{ TF_ZOMBIE,		'Z' },
2186 	{ TF_HOOK,		's' },
2187 
2188 	/* Keep these together -> 'bi' and 'bo'. */
2189 	{ TF_BUSY,		'b' },
2190 	{ TF_BUSY_IN,		'i' },
2191 	{ TF_BUSY_OUT,		'o' },
2192 
2193 	{ 0,			'\0'},
2194 };
2195 
2196 #define	TTY_FLAG_BITS \
2197 	"\20\1NOPREFIX\2INITLOCK\3CALLOUT\4OPENED_IN" \
2198 	"\5OPENED_OUT\6OPENED_CONS\7GONE\10OPENCLOSE" \
2199 	"\11ASYNC\12LITERAL\13HIWAT_IN\14HIWAT_OUT" \
2200 	"\15STOPPED\16EXCLUDE\17BYPASS\20ZOMBIE" \
2201 	"\21HOOK\22BUSY_IN\23BUSY_OUT"
2202 
2203 #define DB_PRINTSYM(name, addr) \
2204 	db_printf("%s  " #name ": ", sep); \
2205 	db_printsym((db_addr_t) addr, DB_STGY_ANY); \
2206 	db_printf("\n");
2207 
2208 static void
2209 _db_show_devsw(const char *sep, const struct ttydevsw *tsw)
2210 {
2211 
2212 	db_printf("%sdevsw: ", sep);
2213 	db_printsym((db_addr_t)tsw, DB_STGY_ANY);
2214 	db_printf(" (%p)\n", tsw);
2215 	DB_PRINTSYM(open, tsw->tsw_open);
2216 	DB_PRINTSYM(close, tsw->tsw_close);
2217 	DB_PRINTSYM(outwakeup, tsw->tsw_outwakeup);
2218 	DB_PRINTSYM(inwakeup, tsw->tsw_inwakeup);
2219 	DB_PRINTSYM(ioctl, tsw->tsw_ioctl);
2220 	DB_PRINTSYM(param, tsw->tsw_param);
2221 	DB_PRINTSYM(modem, tsw->tsw_modem);
2222 	DB_PRINTSYM(mmap, tsw->tsw_mmap);
2223 	DB_PRINTSYM(pktnotify, tsw->tsw_pktnotify);
2224 	DB_PRINTSYM(free, tsw->tsw_free);
2225 }
2226 
2227 static void
2228 _db_show_hooks(const char *sep, const struct ttyhook *th)
2229 {
2230 
2231 	db_printf("%shook: ", sep);
2232 	db_printsym((db_addr_t)th, DB_STGY_ANY);
2233 	db_printf(" (%p)\n", th);
2234 	if (th == NULL)
2235 		return;
2236 	DB_PRINTSYM(rint, th->th_rint);
2237 	DB_PRINTSYM(rint_bypass, th->th_rint_bypass);
2238 	DB_PRINTSYM(rint_done, th->th_rint_done);
2239 	DB_PRINTSYM(rint_poll, th->th_rint_poll);
2240 	DB_PRINTSYM(getc_inject, th->th_getc_inject);
2241 	DB_PRINTSYM(getc_capture, th->th_getc_capture);
2242 	DB_PRINTSYM(getc_poll, th->th_getc_poll);
2243 	DB_PRINTSYM(close, th->th_close);
2244 }
2245 
2246 static void
2247 _db_show_termios(const char *name, const struct termios *t)
2248 {
2249 
2250 	db_printf("%s: iflag 0x%x oflag 0x%x cflag 0x%x "
2251 	    "lflag 0x%x ispeed %u ospeed %u\n", name,
2252 	    t->c_iflag, t->c_oflag, t->c_cflag, t->c_lflag,
2253 	    t->c_ispeed, t->c_ospeed);
2254 }
2255 
2256 /* DDB command to show TTY statistics. */
2257 DB_SHOW_COMMAND(tty, db_show_tty)
2258 {
2259 	struct tty *tp;
2260 
2261 	if (!have_addr) {
2262 		db_printf("usage: show tty <addr>\n");
2263 		return;
2264 	}
2265 	tp = (struct tty *)addr;
2266 
2267 	db_printf("%p: %s\n", tp, tty_devname(tp));
2268 	db_printf("\tmtx: %p\n", tp->t_mtx);
2269 	db_printf("\tflags: 0x%b\n", tp->t_flags, TTY_FLAG_BITS);
2270 	db_printf("\trevokecnt: %u\n", tp->t_revokecnt);
2271 
2272 	/* Buffering mechanisms. */
2273 	db_printf("\tinq: %p begin %u linestart %u reprint %u end %u "
2274 	    "nblocks %u quota %u\n", &tp->t_inq, tp->t_inq.ti_begin,
2275 	    tp->t_inq.ti_linestart, tp->t_inq.ti_reprint, tp->t_inq.ti_end,
2276 	    tp->t_inq.ti_nblocks, tp->t_inq.ti_quota);
2277 	db_printf("\toutq: %p begin %u end %u nblocks %u quota %u\n",
2278 	    &tp->t_outq, tp->t_outq.to_begin, tp->t_outq.to_end,
2279 	    tp->t_outq.to_nblocks, tp->t_outq.to_quota);
2280 	db_printf("\tinlow: %zu\n", tp->t_inlow);
2281 	db_printf("\toutlow: %zu\n", tp->t_outlow);
2282 	_db_show_termios("\ttermios", &tp->t_termios);
2283 	db_printf("\twinsize: row %u col %u xpixel %u ypixel %u\n",
2284 	    tp->t_winsize.ws_row, tp->t_winsize.ws_col,
2285 	    tp->t_winsize.ws_xpixel, tp->t_winsize.ws_ypixel);
2286 	db_printf("\tcolumn: %u\n", tp->t_column);
2287 	db_printf("\twritepos: %u\n", tp->t_writepos);
2288 	db_printf("\tcompatflags: 0x%x\n", tp->t_compatflags);
2289 
2290 	/* Init/lock-state devices. */
2291 	_db_show_termios("\ttermios_init_in", &tp->t_termios_init_in);
2292 	_db_show_termios("\ttermios_init_out", &tp->t_termios_init_out);
2293 	_db_show_termios("\ttermios_lock_in", &tp->t_termios_lock_in);
2294 	_db_show_termios("\ttermios_lock_out", &tp->t_termios_lock_out);
2295 
2296 	/* Hooks */
2297 	_db_show_devsw("\t", tp->t_devsw);
2298 	_db_show_hooks("\t", tp->t_hook);
2299 
2300 	/* Process info. */
2301 	db_printf("\tpgrp: %p gid %d jobc %d\n", tp->t_pgrp,
2302 	    tp->t_pgrp ? tp->t_pgrp->pg_id : 0,
2303 	    tp->t_pgrp ? tp->t_pgrp->pg_jobc : 0);
2304 	db_printf("\tsession: %p", tp->t_session);
2305 	if (tp->t_session != NULL)
2306 	    db_printf(" count %u leader %p tty %p sid %d login %s",
2307 		tp->t_session->s_count, tp->t_session->s_leader,
2308 		tp->t_session->s_ttyp, tp->t_session->s_sid,
2309 		tp->t_session->s_login);
2310 	db_printf("\n");
2311 	db_printf("\tsessioncnt: %u\n", tp->t_sessioncnt);
2312 	db_printf("\tdevswsoftc: %p\n", tp->t_devswsoftc);
2313 	db_printf("\thooksoftc: %p\n", tp->t_hooksoftc);
2314 	db_printf("\tdev: %p\n", tp->t_dev);
2315 }
2316 
2317 /* DDB command to list TTYs. */
2318 DB_SHOW_ALL_COMMAND(ttys, db_show_all_ttys)
2319 {
2320 	struct tty *tp;
2321 	size_t isiz, osiz;
2322 	int i, j;
2323 
2324 	/* Make the output look like `pstat -t'. */
2325 	db_printf("PTR        ");
2326 #if defined(__LP64__)
2327 	db_printf("        ");
2328 #endif
2329 	db_printf("      LINE   INQ  CAN  LIN  LOW  OUTQ  USE  LOW   "
2330 	    "COL  SESS  PGID STATE\n");
2331 
2332 	TAILQ_FOREACH(tp, &tty_list, t_list) {
2333 		isiz = tp->t_inq.ti_nblocks * TTYINQ_DATASIZE;
2334 		osiz = tp->t_outq.to_nblocks * TTYOUTQ_DATASIZE;
2335 
2336 		db_printf("%p %10s %5zu %4u %4u %4zu %5zu %4u %4zu %5u %5d "
2337 		    "%5d ", tp, tty_devname(tp), isiz,
2338 		    tp->t_inq.ti_linestart - tp->t_inq.ti_begin,
2339 		    tp->t_inq.ti_end - tp->t_inq.ti_linestart,
2340 		    isiz - tp->t_inlow, osiz,
2341 		    tp->t_outq.to_end - tp->t_outq.to_begin,
2342 		    osiz - tp->t_outlow, MIN(tp->t_column, 99999),
2343 		    tp->t_session ? tp->t_session->s_sid : 0,
2344 		    tp->t_pgrp ? tp->t_pgrp->pg_id : 0);
2345 
2346 		/* Flag bits. */
2347 		for (i = j = 0; ttystates[i].flag; i++)
2348 			if (tp->t_flags & ttystates[i].flag) {
2349 				db_printf("%c", ttystates[i].val);
2350 				j++;
2351 			}
2352 		if (j == 0)
2353 			db_printf("-");
2354 		db_printf("\n");
2355 	}
2356 }
2357 #endif /* DDB */
2358