xref: /freebsd/sys/kern/tty.c (revision c66ec88fed842fbaad62c30d510644ceb7bd2d71)
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 <fs/devfs/devfs.h>
71 
72 #include <machine/stdarg.h>
73 
74 static MALLOC_DEFINE(M_TTY, "tty", "tty device");
75 
76 static void tty_rel_free(struct tty *tp);
77 
78 static TAILQ_HEAD(, tty) tty_list = TAILQ_HEAD_INITIALIZER(tty_list);
79 static struct sx tty_list_sx;
80 SX_SYSINIT(tty_list, &tty_list_sx, "tty list");
81 static unsigned int tty_list_count = 0;
82 
83 /* Character device of /dev/console. */
84 static struct cdev	*dev_console;
85 static const char	*dev_console_filename;
86 
87 /*
88  * Flags that are supported and stored by this implementation.
89  */
90 #define TTYSUP_IFLAG	(IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK|ISTRIP|\
91 			INLCR|IGNCR|ICRNL|IXON|IXOFF|IXANY|IMAXBEL)
92 #define TTYSUP_OFLAG	(OPOST|ONLCR|TAB3|ONOEOT|OCRNL|ONOCR|ONLRET)
93 #define TTYSUP_LFLAG	(ECHOKE|ECHOE|ECHOK|ECHO|ECHONL|ECHOPRT|\
94 			ECHOCTL|ISIG|ICANON|ALTWERASE|IEXTEN|TOSTOP|\
95 			FLUSHO|NOKERNINFO|NOFLSH)
96 #define TTYSUP_CFLAG	(CIGNORE|CSIZE|CSTOPB|CREAD|PARENB|PARODD|\
97 			HUPCL|CLOCAL|CCTS_OFLOW|CRTS_IFLOW|CDTR_IFLOW|\
98 			CDSR_OFLOW|CCAR_OFLOW|CNO_RTSDTR)
99 
100 #define	TTY_CALLOUT(tp,d) (dev2unit(d) & TTYUNIT_CALLOUT)
101 
102 static int  tty_drainwait = 5 * 60;
103 SYSCTL_INT(_kern, OID_AUTO, tty_drainwait, CTLFLAG_RWTUN,
104     &tty_drainwait, 0, "Default output drain timeout in seconds");
105 
106 /*
107  * Set TTY buffer sizes.
108  */
109 
110 #define	TTYBUF_MAX	65536
111 
112 #ifdef PRINTF_BUFR_SIZE
113 #define	TTY_PRBUF_SIZE	PRINTF_BUFR_SIZE
114 #else
115 #define	TTY_PRBUF_SIZE	256
116 #endif
117 
118 /*
119  * Allocate buffer space if necessary, and set low watermarks, based on speed.
120  * Note that the ttyxxxq_setsize() functions may drop and then reacquire the tty
121  * lock during memory allocation.  They will return ENXIO if the tty disappears
122  * while unlocked.
123  */
124 static int
125 tty_watermarks(struct tty *tp)
126 {
127 	size_t bs = 0;
128 	int error;
129 
130 	/* Provide an input buffer for 2 seconds of data. */
131 	if (tp->t_termios.c_cflag & CREAD)
132 		bs = MIN(tp->t_termios.c_ispeed / 5, TTYBUF_MAX);
133 	error = ttyinq_setsize(&tp->t_inq, tp, bs);
134 	if (error != 0)
135 		return (error);
136 
137 	/* Set low watermark at 10% (when 90% is available). */
138 	tp->t_inlow = (ttyinq_getallocatedsize(&tp->t_inq) * 9) / 10;
139 
140 	/* Provide an output buffer for 2 seconds of data. */
141 	bs = MIN(tp->t_termios.c_ospeed / 5, TTYBUF_MAX);
142 	error = ttyoutq_setsize(&tp->t_outq, tp, bs);
143 	if (error != 0)
144 		return (error);
145 
146 	/* Set low watermark at 10% (when 90% is available). */
147 	tp->t_outlow = (ttyoutq_getallocatedsize(&tp->t_outq) * 9) / 10;
148 
149 	return (0);
150 }
151 
152 static int
153 tty_drain(struct tty *tp, int leaving)
154 {
155 	sbintime_t timeout_at;
156 	size_t bytes;
157 	int error;
158 
159 	if (ttyhook_hashook(tp, getc_inject))
160 		/* buffer is inaccessible */
161 		return (0);
162 
163 	/*
164 	 * For close(), use the recent historic timeout of "1 second without
165 	 * making progress".  For tcdrain(), use t_drainwait as the timeout,
166 	 * with zero meaning "no timeout" which gives POSIX behavior.
167 	 */
168 	if (leaving)
169 		timeout_at = getsbinuptime() + SBT_1S;
170 	else if (tp->t_drainwait != 0)
171 		timeout_at = getsbinuptime() + SBT_1S * tp->t_drainwait;
172 	else
173 		timeout_at = 0;
174 
175 	/*
176 	 * Poll the output buffer and the hardware for completion, at 10 Hz.
177 	 * Polling is required for devices which are not able to signal an
178 	 * interrupt when the transmitter becomes idle (most USB serial devs).
179 	 * The unusual structure of this loop ensures we check for busy one more
180 	 * time after tty_timedwait() returns EWOULDBLOCK, so that success has
181 	 * higher priority than timeout if the IO completed in the last 100mS.
182 	 */
183 	error = 0;
184 	bytes = ttyoutq_bytesused(&tp->t_outq);
185 	for (;;) {
186 		if (ttyoutq_bytesused(&tp->t_outq) == 0 && !ttydevsw_busy(tp))
187 			return (0);
188 		if (error != 0)
189 			return (error);
190 		ttydevsw_outwakeup(tp);
191 		error = tty_timedwait(tp, &tp->t_outwait, hz / 10);
192 		if (error != 0 && error != EWOULDBLOCK)
193 			return (error);
194 		else if (timeout_at == 0 || getsbinuptime() < timeout_at)
195 			error = 0;
196 		else if (leaving && ttyoutq_bytesused(&tp->t_outq) < bytes) {
197 			/* In close, making progress, grant an extra second. */
198 			error = 0;
199 			timeout_at += SBT_1S;
200 			bytes = ttyoutq_bytesused(&tp->t_outq);
201 		}
202 	}
203 }
204 
205 /*
206  * Though ttydev_enter() and ttydev_leave() seem to be related, they
207  * don't have to be used together. ttydev_enter() is used by the cdev
208  * operations to prevent an actual operation from being processed when
209  * the TTY has been abandoned. ttydev_leave() is used by ttydev_open()
210  * and ttydev_close() to determine whether per-TTY data should be
211  * deallocated.
212  */
213 
214 static __inline int
215 ttydev_enter(struct tty *tp)
216 {
217 
218 	tty_lock(tp);
219 
220 	if (tty_gone(tp) || !tty_opened(tp)) {
221 		/* Device is already gone. */
222 		tty_unlock(tp);
223 		return (ENXIO);
224 	}
225 
226 	return (0);
227 }
228 
229 static void
230 ttydev_leave(struct tty *tp)
231 {
232 
233 	tty_assert_locked(tp);
234 
235 	if (tty_opened(tp) || tp->t_flags & TF_OPENCLOSE) {
236 		/* Device is still opened somewhere. */
237 		tty_unlock(tp);
238 		return;
239 	}
240 
241 	tp->t_flags |= TF_OPENCLOSE;
242 
243 	/* Remove console TTY. */
244 	if (constty == tp)
245 		constty_clear();
246 
247 	/* Drain any output. */
248 	if (!tty_gone(tp))
249 		tty_drain(tp, 1);
250 
251 	ttydisc_close(tp);
252 
253 	/* Free i/o queues now since they might be large. */
254 	ttyinq_free(&tp->t_inq);
255 	tp->t_inlow = 0;
256 	ttyoutq_free(&tp->t_outq);
257 	tp->t_outlow = 0;
258 
259 	knlist_clear(&tp->t_inpoll.si_note, 1);
260 	knlist_clear(&tp->t_outpoll.si_note, 1);
261 
262 	if (!tty_gone(tp))
263 		ttydevsw_close(tp);
264 
265 	tp->t_flags &= ~TF_OPENCLOSE;
266 	cv_broadcast(&tp->t_dcdwait);
267 	tty_rel_free(tp);
268 }
269 
270 /*
271  * Operations that are exposed through the character device in /dev.
272  */
273 static int
274 ttydev_open(struct cdev *dev, int oflags, int devtype __unused,
275     struct thread *td)
276 {
277 	struct tty *tp;
278 	int error;
279 
280 	tp = dev->si_drv1;
281 	error = 0;
282 	tty_lock(tp);
283 	if (tty_gone(tp)) {
284 		/* Device is already gone. */
285 		tty_unlock(tp);
286 		return (ENXIO);
287 	}
288 
289 	/*
290 	 * Block when other processes are currently opening or closing
291 	 * the TTY.
292 	 */
293 	while (tp->t_flags & TF_OPENCLOSE) {
294 		error = tty_wait(tp, &tp->t_dcdwait);
295 		if (error != 0) {
296 			tty_unlock(tp);
297 			return (error);
298 		}
299 	}
300 	tp->t_flags |= TF_OPENCLOSE;
301 
302 	/*
303 	 * Make sure the "tty" and "cua" device cannot be opened at the
304 	 * same time.  The console is a "tty" device.
305 	 */
306 	if (TTY_CALLOUT(tp, dev)) {
307 		if (tp->t_flags & (TF_OPENED_CONS | TF_OPENED_IN)) {
308 			error = EBUSY;
309 			goto done;
310 		}
311 	} else {
312 		if (tp->t_flags & TF_OPENED_OUT) {
313 			error = EBUSY;
314 			goto done;
315 		}
316 	}
317 
318 	if (tp->t_flags & TF_EXCLUDE && priv_check(td, PRIV_TTY_EXCLUSIVE)) {
319 		error = EBUSY;
320 		goto done;
321 	}
322 
323 	if (!tty_opened(tp)) {
324 		/* Set proper termios flags. */
325 		if (TTY_CALLOUT(tp, dev))
326 			tp->t_termios = tp->t_termios_init_out;
327 		else
328 			tp->t_termios = tp->t_termios_init_in;
329 		ttydevsw_param(tp, &tp->t_termios);
330 		/* Prevent modem control on callout devices and /dev/console. */
331 		if (TTY_CALLOUT(tp, dev) || dev == dev_console)
332 			tp->t_termios.c_cflag |= CLOCAL;
333 
334 		if ((tp->t_termios.c_cflag & CNO_RTSDTR) == 0)
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_assert_locked(tp);
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;
427 	struct pgrp *pg;
428 	ksiginfo_t ksi;
429 	int error;
430 
431 	MPASS(sig == SIGTTIN || sig == SIGTTOU);
432 	tty_assert_locked(tp);
433 
434 	p = td->td_proc;
435 	for (;;) {
436 		pg = p->p_pgrp;
437 		PGRP_LOCK(pg);
438 		PROC_LOCK(p);
439 
440 		/*
441 		 * pg may no longer be our process group.
442 		 * Re-check after locking.
443 		 */
444 		if (p->p_pgrp != pg) {
445 			PROC_UNLOCK(p);
446 			PGRP_UNLOCK(pg);
447 			continue;
448 		}
449 
450 		/*
451 		 * The process should only sleep, when:
452 		 * - This terminal is the controlling terminal
453 		 * - Its process group is not the foreground process
454 		 *   group
455 		 * - The parent process isn't waiting for the child to
456 		 *   exit
457 		 * - the signal to send to the process isn't masked
458 		 */
459 		if (!tty_is_ctty(tp, p) || p->p_pgrp == tp->t_pgrp) {
460 			/* Allow the action to happen. */
461 			PROC_UNLOCK(p);
462 			PGRP_UNLOCK(pg);
463 			return (0);
464 		}
465 
466 		if (SIGISMEMBER(p->p_sigacts->ps_sigignore, sig) ||
467 		    SIGISMEMBER(td->td_sigmask, sig)) {
468 			/* Only allow them in write()/ioctl(). */
469 			PROC_UNLOCK(p);
470 			PGRP_UNLOCK(pg);
471 			return (sig == SIGTTOU ? 0 : EIO);
472 		}
473 
474 		if ((p->p_flag & P_PPWAIT) != 0 ||
475 		    (pg->pg_flags & PGRP_ORPHANED) != 0) {
476 			/* Don't allow the action to happen. */
477 			PROC_UNLOCK(p);
478 			PGRP_UNLOCK(pg);
479 			return (EIO);
480 		}
481 		PROC_UNLOCK(p);
482 
483 		/*
484 		 * Send the signal and sleep until we're the new
485 		 * foreground process group.
486 		 */
487 		if (sig != 0) {
488 			ksiginfo_init(&ksi);
489 			ksi.ksi_code = SI_KERNEL;
490 			ksi.ksi_signo = sig;
491 			sig = 0;
492 		}
493 
494 		pgsignal(pg, ksi.ksi_signo, 1, &ksi);
495 		PGRP_UNLOCK(pg);
496 
497 		error = tty_wait(tp, &tp->t_bgwait);
498 		if (error)
499 			return (error);
500 	}
501 }
502 
503 static int
504 ttydev_read(struct cdev *dev, struct uio *uio, int ioflag)
505 {
506 	struct tty *tp = dev->si_drv1;
507 	int error;
508 
509 	error = ttydev_enter(tp);
510 	if (error)
511 		goto done;
512 	error = ttydisc_read(tp, uio, ioflag);
513 	tty_unlock(tp);
514 
515 	/*
516 	 * The read() call should not throw an error when the device is
517 	 * being destroyed. Silently convert it to an EOF.
518 	 */
519 done:	if (error == ENXIO)
520 		error = 0;
521 	return (error);
522 }
523 
524 static int
525 ttydev_write(struct cdev *dev, struct uio *uio, int ioflag)
526 {
527 	struct tty *tp = dev->si_drv1;
528 	int error;
529 
530 	error = ttydev_enter(tp);
531 	if (error)
532 		return (error);
533 
534 	if (tp->t_termios.c_lflag & TOSTOP) {
535 		error = tty_wait_background(tp, curthread, SIGTTOU);
536 		if (error)
537 			goto done;
538 	}
539 
540 	if (ioflag & IO_NDELAY && tp->t_flags & TF_BUSY_OUT) {
541 		/* Allow non-blocking writes to bypass serialization. */
542 		error = ttydisc_write(tp, uio, ioflag);
543 	} else {
544 		/* Serialize write() calls. */
545 		while (tp->t_flags & TF_BUSY_OUT) {
546 			error = tty_wait(tp, &tp->t_outserwait);
547 			if (error)
548 				goto done;
549 		}
550 
551 		tp->t_flags |= TF_BUSY_OUT;
552 		error = ttydisc_write(tp, uio, ioflag);
553 		tp->t_flags &= ~TF_BUSY_OUT;
554 		cv_signal(&tp->t_outserwait);
555 	}
556 
557 done:	tty_unlock(tp);
558 	return (error);
559 }
560 
561 static int
562 ttydev_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int fflag,
563     struct thread *td)
564 {
565 	struct tty *tp = dev->si_drv1;
566 	int error;
567 
568 	error = ttydev_enter(tp);
569 	if (error)
570 		return (error);
571 
572 	switch (cmd) {
573 	case TIOCCBRK:
574 	case TIOCCONS:
575 	case TIOCDRAIN:
576 	case TIOCEXCL:
577 	case TIOCFLUSH:
578 	case TIOCNXCL:
579 	case TIOCSBRK:
580 	case TIOCSCTTY:
581 	case TIOCSETA:
582 	case TIOCSETAF:
583 	case TIOCSETAW:
584 	case TIOCSPGRP:
585 	case TIOCSTART:
586 	case TIOCSTAT:
587 	case TIOCSTI:
588 	case TIOCSTOP:
589 	case TIOCSWINSZ:
590 #if 0
591 	case TIOCSDRAINWAIT:
592 	case TIOCSETD:
593 #endif
594 #ifdef COMPAT_43TTY
595 	case  TIOCLBIC:
596 	case  TIOCLBIS:
597 	case  TIOCLSET:
598 	case  TIOCSETC:
599 	case OTIOCSETD:
600 	case  TIOCSETN:
601 	case  TIOCSETP:
602 	case  TIOCSLTC:
603 #endif /* COMPAT_43TTY */
604 		/*
605 		 * If the ioctl() causes the TTY to be modified, let it
606 		 * wait in the background.
607 		 */
608 		error = tty_wait_background(tp, curthread, SIGTTOU);
609 		if (error)
610 			goto done;
611 	}
612 
613 	if (cmd == TIOCSETA || cmd == TIOCSETAW || cmd == TIOCSETAF) {
614 		struct termios *old = &tp->t_termios;
615 		struct termios *new = (struct termios *)data;
616 		struct termios *lock = TTY_CALLOUT(tp, dev) ?
617 		    &tp->t_termios_lock_out : &tp->t_termios_lock_in;
618 		int cc;
619 
620 		/*
621 		 * Lock state devices.  Just overwrite the values of the
622 		 * commands that are currently in use.
623 		 */
624 		new->c_iflag = (old->c_iflag & lock->c_iflag) |
625 		    (new->c_iflag & ~lock->c_iflag);
626 		new->c_oflag = (old->c_oflag & lock->c_oflag) |
627 		    (new->c_oflag & ~lock->c_oflag);
628 		new->c_cflag = (old->c_cflag & lock->c_cflag) |
629 		    (new->c_cflag & ~lock->c_cflag);
630 		new->c_lflag = (old->c_lflag & lock->c_lflag) |
631 		    (new->c_lflag & ~lock->c_lflag);
632 		for (cc = 0; cc < NCCS; ++cc)
633 			if (lock->c_cc[cc])
634 				new->c_cc[cc] = old->c_cc[cc];
635 		if (lock->c_ispeed)
636 			new->c_ispeed = old->c_ispeed;
637 		if (lock->c_ospeed)
638 			new->c_ospeed = old->c_ospeed;
639 	}
640 
641 	error = tty_ioctl(tp, cmd, data, fflag, td);
642 done:	tty_unlock(tp);
643 
644 	return (error);
645 }
646 
647 static int
648 ttydev_poll(struct cdev *dev, int events, struct thread *td)
649 {
650 	struct tty *tp = dev->si_drv1;
651 	int error, revents = 0;
652 
653 	error = ttydev_enter(tp);
654 	if (error)
655 		return ((events & (POLLIN|POLLRDNORM)) | POLLHUP);
656 
657 	if (events & (POLLIN|POLLRDNORM)) {
658 		/* See if we can read something. */
659 		if (ttydisc_read_poll(tp) > 0)
660 			revents |= events & (POLLIN|POLLRDNORM);
661 	}
662 
663 	if (tp->t_flags & TF_ZOMBIE) {
664 		/* Hangup flag on zombie state. */
665 		revents |= POLLHUP;
666 	} else if (events & (POLLOUT|POLLWRNORM)) {
667 		/* See if we can write something. */
668 		if (ttydisc_write_poll(tp) > 0)
669 			revents |= events & (POLLOUT|POLLWRNORM);
670 	}
671 
672 	if (revents == 0) {
673 		if (events & (POLLIN|POLLRDNORM))
674 			selrecord(td, &tp->t_inpoll);
675 		if (events & (POLLOUT|POLLWRNORM))
676 			selrecord(td, &tp->t_outpoll);
677 	}
678 
679 	tty_unlock(tp);
680 
681 	return (revents);
682 }
683 
684 static int
685 ttydev_mmap(struct cdev *dev, vm_ooffset_t offset, vm_paddr_t *paddr,
686     int nprot, vm_memattr_t *memattr)
687 {
688 	struct tty *tp = dev->si_drv1;
689 	int error;
690 
691 	/* Handle mmap() through the driver. */
692 
693 	error = ttydev_enter(tp);
694 	if (error)
695 		return (-1);
696 	error = ttydevsw_mmap(tp, offset, paddr, nprot, memattr);
697 	tty_unlock(tp);
698 
699 	return (error);
700 }
701 
702 /*
703  * kqueue support.
704  */
705 
706 static void
707 tty_kqops_read_detach(struct knote *kn)
708 {
709 	struct tty *tp = kn->kn_hook;
710 
711 	knlist_remove(&tp->t_inpoll.si_note, kn, 0);
712 }
713 
714 static int
715 tty_kqops_read_event(struct knote *kn, long hint __unused)
716 {
717 	struct tty *tp = kn->kn_hook;
718 
719 	tty_assert_locked(tp);
720 
721 	if (tty_gone(tp) || tp->t_flags & TF_ZOMBIE) {
722 		kn->kn_flags |= EV_EOF;
723 		return (1);
724 	} else {
725 		kn->kn_data = ttydisc_read_poll(tp);
726 		return (kn->kn_data > 0);
727 	}
728 }
729 
730 static void
731 tty_kqops_write_detach(struct knote *kn)
732 {
733 	struct tty *tp = kn->kn_hook;
734 
735 	knlist_remove(&tp->t_outpoll.si_note, kn, 0);
736 }
737 
738 static int
739 tty_kqops_write_event(struct knote *kn, long hint __unused)
740 {
741 	struct tty *tp = kn->kn_hook;
742 
743 	tty_assert_locked(tp);
744 
745 	if (tty_gone(tp)) {
746 		kn->kn_flags |= EV_EOF;
747 		return (1);
748 	} else {
749 		kn->kn_data = ttydisc_write_poll(tp);
750 		return (kn->kn_data > 0);
751 	}
752 }
753 
754 static struct filterops tty_kqops_read = {
755 	.f_isfd = 1,
756 	.f_detach = tty_kqops_read_detach,
757 	.f_event = tty_kqops_read_event,
758 };
759 
760 static struct filterops tty_kqops_write = {
761 	.f_isfd = 1,
762 	.f_detach = tty_kqops_write_detach,
763 	.f_event = tty_kqops_write_event,
764 };
765 
766 static int
767 ttydev_kqfilter(struct cdev *dev, struct knote *kn)
768 {
769 	struct tty *tp = dev->si_drv1;
770 	int error;
771 
772 	error = ttydev_enter(tp);
773 	if (error)
774 		return (error);
775 
776 	switch (kn->kn_filter) {
777 	case EVFILT_READ:
778 		kn->kn_hook = tp;
779 		kn->kn_fop = &tty_kqops_read;
780 		knlist_add(&tp->t_inpoll.si_note, kn, 1);
781 		break;
782 	case EVFILT_WRITE:
783 		kn->kn_hook = tp;
784 		kn->kn_fop = &tty_kqops_write;
785 		knlist_add(&tp->t_outpoll.si_note, kn, 1);
786 		break;
787 	default:
788 		error = EINVAL;
789 		break;
790 	}
791 
792 	tty_unlock(tp);
793 	return (error);
794 }
795 
796 static struct cdevsw ttydev_cdevsw = {
797 	.d_version	= D_VERSION,
798 	.d_open		= ttydev_open,
799 	.d_close	= ttydev_close,
800 	.d_read		= ttydev_read,
801 	.d_write	= ttydev_write,
802 	.d_ioctl	= ttydev_ioctl,
803 	.d_kqfilter	= ttydev_kqfilter,
804 	.d_poll		= ttydev_poll,
805 	.d_mmap		= ttydev_mmap,
806 	.d_name		= "ttydev",
807 	.d_flags	= D_TTY,
808 };
809 
810 /*
811  * Init/lock-state devices
812  */
813 
814 static int
815 ttyil_open(struct cdev *dev, int oflags __unused, int devtype __unused,
816     struct thread *td)
817 {
818 	struct tty *tp;
819 	int error;
820 
821 	tp = dev->si_drv1;
822 	error = 0;
823 	tty_lock(tp);
824 	if (tty_gone(tp))
825 		error = ENODEV;
826 	tty_unlock(tp);
827 
828 	return (error);
829 }
830 
831 static int
832 ttyil_close(struct cdev *dev __unused, int flag __unused, int mode __unused,
833     struct thread *td __unused)
834 {
835 
836 	return (0);
837 }
838 
839 static int
840 ttyil_rdwr(struct cdev *dev __unused, struct uio *uio __unused,
841     int ioflag __unused)
842 {
843 
844 	return (ENODEV);
845 }
846 
847 static int
848 ttyil_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int fflag,
849     struct thread *td)
850 {
851 	struct tty *tp = dev->si_drv1;
852 	int error;
853 
854 	tty_lock(tp);
855 	if (tty_gone(tp)) {
856 		error = ENODEV;
857 		goto done;
858 	}
859 
860 	error = ttydevsw_cioctl(tp, dev2unit(dev), cmd, data, td);
861 	if (error != ENOIOCTL)
862 		goto done;
863 	error = 0;
864 
865 	switch (cmd) {
866 	case TIOCGETA:
867 		/* Obtain terminal flags through tcgetattr(). */
868 		*(struct termios*)data = *(struct termios*)dev->si_drv2;
869 		break;
870 	case TIOCSETA:
871 		/* Set terminal flags through tcsetattr(). */
872 		error = priv_check(td, PRIV_TTY_SETA);
873 		if (error)
874 			break;
875 		*(struct termios*)dev->si_drv2 = *(struct termios*)data;
876 		break;
877 	case TIOCGETD:
878 		*(int *)data = TTYDISC;
879 		break;
880 	case TIOCGWINSZ:
881 		bzero(data, sizeof(struct winsize));
882 		break;
883 	default:
884 		error = ENOTTY;
885 	}
886 
887 done:	tty_unlock(tp);
888 	return (error);
889 }
890 
891 static struct cdevsw ttyil_cdevsw = {
892 	.d_version	= D_VERSION,
893 	.d_open		= ttyil_open,
894 	.d_close	= ttyil_close,
895 	.d_read		= ttyil_rdwr,
896 	.d_write	= ttyil_rdwr,
897 	.d_ioctl	= ttyil_ioctl,
898 	.d_name		= "ttyil",
899 	.d_flags	= D_TTY,
900 };
901 
902 static void
903 tty_init_termios(struct tty *tp)
904 {
905 	struct termios *t = &tp->t_termios_init_in;
906 
907 	t->c_cflag = TTYDEF_CFLAG;
908 	t->c_iflag = TTYDEF_IFLAG;
909 	t->c_lflag = TTYDEF_LFLAG;
910 	t->c_oflag = TTYDEF_OFLAG;
911 	t->c_ispeed = TTYDEF_SPEED;
912 	t->c_ospeed = TTYDEF_SPEED;
913 	memcpy(&t->c_cc, ttydefchars, sizeof ttydefchars);
914 
915 	tp->t_termios_init_out = *t;
916 }
917 
918 void
919 tty_init_console(struct tty *tp, speed_t s)
920 {
921 	struct termios *ti = &tp->t_termios_init_in;
922 	struct termios *to = &tp->t_termios_init_out;
923 
924 	if (s != 0) {
925 		ti->c_ispeed = ti->c_ospeed = s;
926 		to->c_ispeed = to->c_ospeed = s;
927 	}
928 
929 	ti->c_cflag |= CLOCAL;
930 	to->c_cflag |= CLOCAL;
931 }
932 
933 /*
934  * Standard device routine implementations, mostly meant for
935  * pseudo-terminal device drivers. When a driver creates a new terminal
936  * device class, missing routines are patched.
937  */
938 
939 static int
940 ttydevsw_defopen(struct tty *tp __unused)
941 {
942 
943 	return (0);
944 }
945 
946 static void
947 ttydevsw_defclose(struct tty *tp __unused)
948 {
949 
950 }
951 
952 static void
953 ttydevsw_defoutwakeup(struct tty *tp __unused)
954 {
955 
956 	panic("Terminal device has output, while not implemented");
957 }
958 
959 static void
960 ttydevsw_definwakeup(struct tty *tp __unused)
961 {
962 
963 }
964 
965 static int
966 ttydevsw_defioctl(struct tty *tp __unused, u_long cmd __unused,
967     caddr_t data __unused, struct thread *td __unused)
968 {
969 
970 	return (ENOIOCTL);
971 }
972 
973 static int
974 ttydevsw_defcioctl(struct tty *tp __unused, int unit __unused,
975     u_long cmd __unused, caddr_t data __unused, struct thread *td __unused)
976 {
977 
978 	return (ENOIOCTL);
979 }
980 
981 static int
982 ttydevsw_defparam(struct tty *tp __unused, struct termios *t)
983 {
984 
985 	/*
986 	 * Allow the baud rate to be adjusted for pseudo-devices, but at
987 	 * least restrict it to 115200 to prevent excessive buffer
988 	 * usage.  Also disallow 0, to prevent foot shooting.
989 	 */
990 	if (t->c_ispeed < B50)
991 		t->c_ispeed = B50;
992 	else if (t->c_ispeed > B115200)
993 		t->c_ispeed = B115200;
994 	if (t->c_ospeed < B50)
995 		t->c_ospeed = B50;
996 	else if (t->c_ospeed > B115200)
997 		t->c_ospeed = B115200;
998 	t->c_cflag |= CREAD;
999 
1000 	return (0);
1001 }
1002 
1003 static int
1004 ttydevsw_defmodem(struct tty *tp __unused, int sigon __unused,
1005     int sigoff __unused)
1006 {
1007 
1008 	/* Simulate a carrier to make the TTY layer happy. */
1009 	return (SER_DCD);
1010 }
1011 
1012 static int
1013 ttydevsw_defmmap(struct tty *tp __unused, vm_ooffset_t offset __unused,
1014     vm_paddr_t *paddr __unused, int nprot __unused,
1015     vm_memattr_t *memattr __unused)
1016 {
1017 
1018 	return (-1);
1019 }
1020 
1021 static void
1022 ttydevsw_defpktnotify(struct tty *tp __unused, char event __unused)
1023 {
1024 
1025 }
1026 
1027 static void
1028 ttydevsw_deffree(void *softc __unused)
1029 {
1030 
1031 	panic("Terminal device freed without a free-handler");
1032 }
1033 
1034 static bool
1035 ttydevsw_defbusy(struct tty *tp __unused)
1036 {
1037 
1038 	return (FALSE);
1039 }
1040 
1041 /*
1042  * TTY allocation and deallocation. TTY devices can be deallocated when
1043  * the driver doesn't use it anymore, when the TTY isn't a session's
1044  * controlling TTY and when the device node isn't opened through devfs.
1045  */
1046 
1047 struct tty *
1048 tty_alloc(struct ttydevsw *tsw, void *sc)
1049 {
1050 
1051 	return (tty_alloc_mutex(tsw, sc, NULL));
1052 }
1053 
1054 struct tty *
1055 tty_alloc_mutex(struct ttydevsw *tsw, void *sc, struct mtx *mutex)
1056 {
1057 	struct tty *tp;
1058 
1059 	/* Make sure the driver defines all routines. */
1060 #define PATCH_FUNC(x) do {				\
1061 	if (tsw->tsw_ ## x == NULL)			\
1062 		tsw->tsw_ ## x = ttydevsw_def ## x;	\
1063 } while (0)
1064 	PATCH_FUNC(open);
1065 	PATCH_FUNC(close);
1066 	PATCH_FUNC(outwakeup);
1067 	PATCH_FUNC(inwakeup);
1068 	PATCH_FUNC(ioctl);
1069 	PATCH_FUNC(cioctl);
1070 	PATCH_FUNC(param);
1071 	PATCH_FUNC(modem);
1072 	PATCH_FUNC(mmap);
1073 	PATCH_FUNC(pktnotify);
1074 	PATCH_FUNC(free);
1075 	PATCH_FUNC(busy);
1076 #undef PATCH_FUNC
1077 
1078 	tp = malloc(sizeof(struct tty) + TTY_PRBUF_SIZE, M_TTY,
1079 	    M_WAITOK | M_ZERO);
1080 	tp->t_prbufsz = TTY_PRBUF_SIZE;
1081 	tp->t_devsw = tsw;
1082 	tp->t_devswsoftc = sc;
1083 	tp->t_flags = tsw->tsw_flags;
1084 	tp->t_drainwait = tty_drainwait;
1085 
1086 	tty_init_termios(tp);
1087 
1088 	cv_init(&tp->t_inwait, "ttyin");
1089 	cv_init(&tp->t_outwait, "ttyout");
1090 	cv_init(&tp->t_outserwait, "ttyosr");
1091 	cv_init(&tp->t_bgwait, "ttybg");
1092 	cv_init(&tp->t_dcdwait, "ttydcd");
1093 
1094 	/* Allow drivers to use a custom mutex to lock the TTY. */
1095 	if (mutex != NULL) {
1096 		tp->t_mtx = mutex;
1097 	} else {
1098 		tp->t_mtx = &tp->t_mtxobj;
1099 		mtx_init(&tp->t_mtxobj, "ttymtx", NULL, MTX_DEF);
1100 	}
1101 
1102 	knlist_init_mtx(&tp->t_inpoll.si_note, tp->t_mtx);
1103 	knlist_init_mtx(&tp->t_outpoll.si_note, tp->t_mtx);
1104 
1105 	return (tp);
1106 }
1107 
1108 static void
1109 tty_dealloc(void *arg)
1110 {
1111 	struct tty *tp = arg;
1112 
1113 	/*
1114 	 * ttyydev_leave() usually frees the i/o queues earlier, but it is
1115 	 * not always called between queue allocation and here.  The queues
1116 	 * may be allocated by ioctls on a pty control device without the
1117 	 * corresponding pty slave device ever being open, or after it is
1118 	 * closed.
1119 	 */
1120 	ttyinq_free(&tp->t_inq);
1121 	ttyoutq_free(&tp->t_outq);
1122 	seldrain(&tp->t_inpoll);
1123 	seldrain(&tp->t_outpoll);
1124 	knlist_destroy(&tp->t_inpoll.si_note);
1125 	knlist_destroy(&tp->t_outpoll.si_note);
1126 
1127 	cv_destroy(&tp->t_inwait);
1128 	cv_destroy(&tp->t_outwait);
1129 	cv_destroy(&tp->t_bgwait);
1130 	cv_destroy(&tp->t_dcdwait);
1131 	cv_destroy(&tp->t_outserwait);
1132 
1133 	if (tp->t_mtx == &tp->t_mtxobj)
1134 		mtx_destroy(&tp->t_mtxobj);
1135 	ttydevsw_free(tp);
1136 	free(tp, M_TTY);
1137 }
1138 
1139 static void
1140 tty_rel_free(struct tty *tp)
1141 {
1142 	struct cdev *dev;
1143 
1144 	tty_assert_locked(tp);
1145 
1146 #define	TF_ACTIVITY	(TF_GONE|TF_OPENED|TF_HOOK|TF_OPENCLOSE)
1147 	if (tp->t_sessioncnt != 0 || (tp->t_flags & TF_ACTIVITY) != TF_GONE) {
1148 		/* TTY is still in use. */
1149 		tty_unlock(tp);
1150 		return;
1151 	}
1152 
1153 	/* Stop asynchronous I/O. */
1154 	funsetown(&tp->t_sigio);
1155 
1156 	/* TTY can be deallocated. */
1157 	dev = tp->t_dev;
1158 	tp->t_dev = NULL;
1159 	tty_unlock(tp);
1160 
1161 	if (dev != NULL) {
1162 		sx_xlock(&tty_list_sx);
1163 		TAILQ_REMOVE(&tty_list, tp, t_list);
1164 		tty_list_count--;
1165 		sx_xunlock(&tty_list_sx);
1166 		destroy_dev_sched_cb(dev, tty_dealloc, tp);
1167 	}
1168 }
1169 
1170 void
1171 tty_rel_pgrp(struct tty *tp, struct pgrp *pg)
1172 {
1173 
1174 	MPASS(tp->t_sessioncnt > 0);
1175 	tty_assert_locked(tp);
1176 
1177 	if (tp->t_pgrp == pg)
1178 		tp->t_pgrp = NULL;
1179 
1180 	tty_unlock(tp);
1181 }
1182 
1183 void
1184 tty_rel_sess(struct tty *tp, struct session *sess)
1185 {
1186 
1187 	MPASS(tp->t_sessioncnt > 0);
1188 
1189 	/* Current session has left. */
1190 	if (tp->t_session == sess) {
1191 		tp->t_session = NULL;
1192 		MPASS(tp->t_pgrp == NULL);
1193 	}
1194 	tp->t_sessioncnt--;
1195 	tty_rel_free(tp);
1196 }
1197 
1198 void
1199 tty_rel_gone(struct tty *tp)
1200 {
1201 
1202 	tty_assert_locked(tp);
1203 	MPASS(!tty_gone(tp));
1204 
1205 	/* Simulate carrier removal. */
1206 	ttydisc_modem(tp, 0);
1207 
1208 	/* Wake up all blocked threads. */
1209 	tty_wakeup(tp, FREAD|FWRITE);
1210 	cv_broadcast(&tp->t_bgwait);
1211 	cv_broadcast(&tp->t_dcdwait);
1212 
1213 	tp->t_flags |= TF_GONE;
1214 	tty_rel_free(tp);
1215 }
1216 
1217 static int
1218 tty_drop_ctty(struct tty *tp, struct proc *p)
1219 {
1220 	struct session *session;
1221 	struct vnode *vp;
1222 
1223 	/*
1224 	 * This looks terrible, but it's generally safe as long as the tty
1225 	 * hasn't gone away while we had the lock dropped.  All of our sanity
1226 	 * checking that this operation is OK happens after we've picked it back
1227 	 * up, so other state changes are generally not fatal and the potential
1228 	 * for this particular operation to happen out-of-order in a
1229 	 * multithreaded scenario is likely a non-issue.
1230 	 */
1231 	tty_unlock(tp);
1232 	sx_xlock(&proctree_lock);
1233 	tty_lock(tp);
1234 	if (tty_gone(tp)) {
1235 		sx_xunlock(&proctree_lock);
1236 		return (ENODEV);
1237 	}
1238 
1239 	/*
1240 	 * If the session doesn't have a controlling TTY, or if we weren't
1241 	 * invoked on the controlling TTY, we'll return ENOIOCTL as we've
1242 	 * historically done.
1243 	 */
1244 	session = p->p_session;
1245 	if (session->s_ttyp == NULL || session->s_ttyp != tp) {
1246 		sx_xunlock(&proctree_lock);
1247 		return (ENOTTY);
1248 	}
1249 
1250 	if (!SESS_LEADER(p)) {
1251 		sx_xunlock(&proctree_lock);
1252 		return (EPERM);
1253 	}
1254 
1255 	PROC_LOCK(p);
1256 	SESS_LOCK(session);
1257 	vp = session->s_ttyvp;
1258 	session->s_ttyp = NULL;
1259 	session->s_ttyvp = NULL;
1260 	session->s_ttydp = NULL;
1261 	SESS_UNLOCK(session);
1262 
1263 	tp->t_sessioncnt--;
1264 	p->p_flag &= ~P_CONTROLT;
1265 	PROC_UNLOCK(p);
1266 	sx_xunlock(&proctree_lock);
1267 
1268 	/*
1269 	 * If we did have a vnode, release our reference.  Ordinarily we manage
1270 	 * these at the devfs layer, but we can't necessarily know that we were
1271 	 * invoked on the vnode referenced in the session (i.e. the vnode we
1272 	 * hold a reference to).  We explicitly don't check VBAD/VIRF_DOOMED here
1273 	 * to avoid a vnode leak -- in circumstances elsewhere where we'd hit a
1274 	 * VIRF_DOOMED vnode, release has been deferred until the controlling TTY
1275 	 * is either changed or released.
1276 	 */
1277 	if (vp != NULL)
1278 		devfs_ctty_unref(vp);
1279 	return (0);
1280 }
1281 
1282 /*
1283  * Exposing information about current TTY's through sysctl
1284  */
1285 
1286 static void
1287 tty_to_xtty(struct tty *tp, struct xtty *xt)
1288 {
1289 
1290 	tty_assert_locked(tp);
1291 
1292 	xt->xt_size = sizeof(struct xtty);
1293 	xt->xt_insize = ttyinq_getsize(&tp->t_inq);
1294 	xt->xt_incc = ttyinq_bytescanonicalized(&tp->t_inq);
1295 	xt->xt_inlc = ttyinq_bytesline(&tp->t_inq);
1296 	xt->xt_inlow = tp->t_inlow;
1297 	xt->xt_outsize = ttyoutq_getsize(&tp->t_outq);
1298 	xt->xt_outcc = ttyoutq_bytesused(&tp->t_outq);
1299 	xt->xt_outlow = tp->t_outlow;
1300 	xt->xt_column = tp->t_column;
1301 	xt->xt_pgid = tp->t_pgrp ? tp->t_pgrp->pg_id : 0;
1302 	xt->xt_sid = tp->t_session ? tp->t_session->s_sid : 0;
1303 	xt->xt_flags = tp->t_flags;
1304 	xt->xt_dev = tp->t_dev ? dev2udev(tp->t_dev) : (uint32_t)NODEV;
1305 }
1306 
1307 static int
1308 sysctl_kern_ttys(SYSCTL_HANDLER_ARGS)
1309 {
1310 	unsigned long lsize;
1311 	struct xtty *xtlist, *xt;
1312 	struct tty *tp;
1313 	int error;
1314 
1315 	sx_slock(&tty_list_sx);
1316 	lsize = tty_list_count * sizeof(struct xtty);
1317 	if (lsize == 0) {
1318 		sx_sunlock(&tty_list_sx);
1319 		return (0);
1320 	}
1321 
1322 	xtlist = xt = malloc(lsize, M_TTY, M_WAITOK);
1323 
1324 	TAILQ_FOREACH(tp, &tty_list, t_list) {
1325 		tty_lock(tp);
1326 		tty_to_xtty(tp, xt);
1327 		tty_unlock(tp);
1328 		xt++;
1329 	}
1330 	sx_sunlock(&tty_list_sx);
1331 
1332 	error = SYSCTL_OUT(req, xtlist, lsize);
1333 	free(xtlist, M_TTY);
1334 	return (error);
1335 }
1336 
1337 SYSCTL_PROC(_kern, OID_AUTO, ttys, CTLTYPE_OPAQUE|CTLFLAG_RD|CTLFLAG_MPSAFE,
1338 	0, 0, sysctl_kern_ttys, "S,xtty", "List of TTYs");
1339 
1340 /*
1341  * Device node creation. Device has been set up, now we can expose it to
1342  * the user.
1343  */
1344 
1345 int
1346 tty_makedevf(struct tty *tp, struct ucred *cred, int flags,
1347     const char *fmt, ...)
1348 {
1349 	va_list ap;
1350 	struct make_dev_args args;
1351 	struct cdev *dev, *init, *lock, *cua, *cinit, *clock;
1352 	const char *prefix = "tty";
1353 	char name[SPECNAMELEN - 3]; /* for "tty" and "cua". */
1354 	uid_t uid;
1355 	gid_t gid;
1356 	mode_t mode;
1357 	int error;
1358 
1359 	/* Remove "tty" prefix from devices like PTY's. */
1360 	if (tp->t_flags & TF_NOPREFIX)
1361 		prefix = "";
1362 
1363 	va_start(ap, fmt);
1364 	vsnrprintf(name, sizeof name, 32, fmt, ap);
1365 	va_end(ap);
1366 
1367 	if (cred == NULL) {
1368 		/* System device. */
1369 		uid = UID_ROOT;
1370 		gid = GID_WHEEL;
1371 		mode = S_IRUSR|S_IWUSR;
1372 	} else {
1373 		/* User device. */
1374 		uid = cred->cr_ruid;
1375 		gid = GID_TTY;
1376 		mode = S_IRUSR|S_IWUSR|S_IWGRP;
1377 	}
1378 
1379 	flags = flags & TTYMK_CLONING ? MAKEDEV_REF : 0;
1380 	flags |= MAKEDEV_CHECKNAME;
1381 
1382 	/* Master call-in device. */
1383 	make_dev_args_init(&args);
1384 	args.mda_flags = flags;
1385 	args.mda_devsw = &ttydev_cdevsw;
1386 	args.mda_cr = cred;
1387 	args.mda_uid = uid;
1388 	args.mda_gid = gid;
1389 	args.mda_mode = mode;
1390 	args.mda_si_drv1 = tp;
1391 	error = make_dev_s(&args, &dev, "%s%s", prefix, name);
1392 	if (error != 0)
1393 		return (error);
1394 	tp->t_dev = dev;
1395 
1396 	init = lock = cua = cinit = clock = NULL;
1397 
1398 	/* Slave call-in devices. */
1399 	if (tp->t_flags & TF_INITLOCK) {
1400 		args.mda_devsw = &ttyil_cdevsw;
1401 		args.mda_unit = TTYUNIT_INIT;
1402 		args.mda_si_drv1 = tp;
1403 		args.mda_si_drv2 = &tp->t_termios_init_in;
1404 		error = make_dev_s(&args, &init, "%s%s.init", prefix, name);
1405 		if (error != 0)
1406 			goto fail;
1407 		dev_depends(dev, init);
1408 
1409 		args.mda_unit = TTYUNIT_LOCK;
1410 		args.mda_si_drv2 = &tp->t_termios_lock_in;
1411 		error = make_dev_s(&args, &lock, "%s%s.lock", prefix, name);
1412 		if (error != 0)
1413 			goto fail;
1414 		dev_depends(dev, lock);
1415 	}
1416 
1417 	/* Call-out devices. */
1418 	if (tp->t_flags & TF_CALLOUT) {
1419 		make_dev_args_init(&args);
1420 		args.mda_flags = flags;
1421 		args.mda_devsw = &ttydev_cdevsw;
1422 		args.mda_cr = cred;
1423 		args.mda_uid = UID_UUCP;
1424 		args.mda_gid = GID_DIALER;
1425 		args.mda_mode = 0660;
1426 		args.mda_unit = TTYUNIT_CALLOUT;
1427 		args.mda_si_drv1 = tp;
1428 		error = make_dev_s(&args, &cua, "cua%s", name);
1429 		if (error != 0)
1430 			goto fail;
1431 		dev_depends(dev, cua);
1432 
1433 		/* Slave call-out devices. */
1434 		if (tp->t_flags & TF_INITLOCK) {
1435 			args.mda_devsw = &ttyil_cdevsw;
1436 			args.mda_unit = TTYUNIT_CALLOUT | TTYUNIT_INIT;
1437 			args.mda_si_drv2 = &tp->t_termios_init_out;
1438 			error = make_dev_s(&args, &cinit, "cua%s.init", name);
1439 			if (error != 0)
1440 				goto fail;
1441 			dev_depends(dev, cinit);
1442 
1443 			args.mda_unit = TTYUNIT_CALLOUT | TTYUNIT_LOCK;
1444 			args.mda_si_drv2 = &tp->t_termios_lock_out;
1445 			error = make_dev_s(&args, &clock, "cua%s.lock", name);
1446 			if (error != 0)
1447 				goto fail;
1448 			dev_depends(dev, clock);
1449 		}
1450 	}
1451 
1452 	sx_xlock(&tty_list_sx);
1453 	TAILQ_INSERT_TAIL(&tty_list, tp, t_list);
1454 	tty_list_count++;
1455 	sx_xunlock(&tty_list_sx);
1456 
1457 	return (0);
1458 
1459 fail:
1460 	destroy_dev(dev);
1461 	if (init)
1462 		destroy_dev(init);
1463 	if (lock)
1464 		destroy_dev(lock);
1465 	if (cinit)
1466 		destroy_dev(cinit);
1467 	if (clock)
1468 		destroy_dev(clock);
1469 
1470 	return (error);
1471 }
1472 
1473 /*
1474  * Signalling processes.
1475  */
1476 
1477 void
1478 tty_signal_sessleader(struct tty *tp, int sig)
1479 {
1480 	struct proc *p;
1481 	struct session *s;
1482 
1483 	tty_assert_locked(tp);
1484 	MPASS(sig >= 1 && sig < NSIG);
1485 
1486 	/* Make signals start output again. */
1487 	tp->t_flags &= ~TF_STOPPED;
1488 	tp->t_termios.c_lflag &= ~FLUSHO;
1489 
1490 	/*
1491 	 * Load s_leader exactly once to avoid race where s_leader is
1492 	 * set to NULL by a concurrent invocation of killjobc() by the
1493 	 * session leader.  Note that we are not holding t_session's
1494 	 * lock for the read.
1495 	 */
1496 	if ((s = tp->t_session) != NULL &&
1497 	    (p = atomic_load_ptr(&s->s_leader)) != NULL) {
1498 		PROC_LOCK(p);
1499 		kern_psignal(p, sig);
1500 		PROC_UNLOCK(p);
1501 	}
1502 }
1503 
1504 void
1505 tty_signal_pgrp(struct tty *tp, int sig)
1506 {
1507 	ksiginfo_t ksi;
1508 
1509 	tty_assert_locked(tp);
1510 	MPASS(sig >= 1 && sig < NSIG);
1511 
1512 	/* Make signals start output again. */
1513 	tp->t_flags &= ~TF_STOPPED;
1514 	tp->t_termios.c_lflag &= ~FLUSHO;
1515 
1516 	if (sig == SIGINFO && !(tp->t_termios.c_lflag & NOKERNINFO))
1517 		tty_info(tp);
1518 	if (tp->t_pgrp != NULL) {
1519 		ksiginfo_init(&ksi);
1520 		ksi.ksi_signo = sig;
1521 		ksi.ksi_code = SI_KERNEL;
1522 		PGRP_LOCK(tp->t_pgrp);
1523 		pgsignal(tp->t_pgrp, sig, 1, &ksi);
1524 		PGRP_UNLOCK(tp->t_pgrp);
1525 	}
1526 }
1527 
1528 void
1529 tty_wakeup(struct tty *tp, int flags)
1530 {
1531 
1532 	if (tp->t_flags & TF_ASYNC && tp->t_sigio != NULL)
1533 		pgsigio(&tp->t_sigio, SIGIO, (tp->t_session != NULL));
1534 
1535 	if (flags & FWRITE) {
1536 		cv_broadcast(&tp->t_outwait);
1537 		selwakeup(&tp->t_outpoll);
1538 		KNOTE_LOCKED(&tp->t_outpoll.si_note, 0);
1539 	}
1540 	if (flags & FREAD) {
1541 		cv_broadcast(&tp->t_inwait);
1542 		selwakeup(&tp->t_inpoll);
1543 		KNOTE_LOCKED(&tp->t_inpoll.si_note, 0);
1544 	}
1545 }
1546 
1547 int
1548 tty_wait(struct tty *tp, struct cv *cv)
1549 {
1550 	int error;
1551 	int revokecnt = tp->t_revokecnt;
1552 
1553 	tty_lock_assert(tp, MA_OWNED|MA_NOTRECURSED);
1554 	MPASS(!tty_gone(tp));
1555 
1556 	error = cv_wait_sig(cv, tp->t_mtx);
1557 
1558 	/* Bail out when the device slipped away. */
1559 	if (tty_gone(tp))
1560 		return (ENXIO);
1561 
1562 	/* Restart the system call when we may have been revoked. */
1563 	if (tp->t_revokecnt != revokecnt)
1564 		return (ERESTART);
1565 
1566 	return (error);
1567 }
1568 
1569 int
1570 tty_timedwait(struct tty *tp, struct cv *cv, int hz)
1571 {
1572 	int error;
1573 	int revokecnt = tp->t_revokecnt;
1574 
1575 	tty_lock_assert(tp, MA_OWNED|MA_NOTRECURSED);
1576 	MPASS(!tty_gone(tp));
1577 
1578 	error = cv_timedwait_sig(cv, tp->t_mtx, hz);
1579 
1580 	/* Bail out when the device slipped away. */
1581 	if (tty_gone(tp))
1582 		return (ENXIO);
1583 
1584 	/* Restart the system call when we may have been revoked. */
1585 	if (tp->t_revokecnt != revokecnt)
1586 		return (ERESTART);
1587 
1588 	return (error);
1589 }
1590 
1591 void
1592 tty_flush(struct tty *tp, int flags)
1593 {
1594 
1595 	if (flags & FWRITE) {
1596 		tp->t_flags &= ~TF_HIWAT_OUT;
1597 		ttyoutq_flush(&tp->t_outq);
1598 		tty_wakeup(tp, FWRITE);
1599 		if (!tty_gone(tp)) {
1600 			ttydevsw_outwakeup(tp);
1601 			ttydevsw_pktnotify(tp, TIOCPKT_FLUSHWRITE);
1602 		}
1603 	}
1604 	if (flags & FREAD) {
1605 		tty_hiwat_in_unblock(tp);
1606 		ttyinq_flush(&tp->t_inq);
1607 		tty_wakeup(tp, FREAD);
1608 		if (!tty_gone(tp)) {
1609 			ttydevsw_inwakeup(tp);
1610 			ttydevsw_pktnotify(tp, TIOCPKT_FLUSHREAD);
1611 		}
1612 	}
1613 }
1614 
1615 void
1616 tty_set_winsize(struct tty *tp, const struct winsize *wsz)
1617 {
1618 
1619 	if (memcmp(&tp->t_winsize, wsz, sizeof(*wsz)) == 0)
1620 		return;
1621 	tp->t_winsize = *wsz;
1622 	tty_signal_pgrp(tp, SIGWINCH);
1623 }
1624 
1625 static int
1626 tty_generic_ioctl(struct tty *tp, u_long cmd, void *data, int fflag,
1627     struct thread *td)
1628 {
1629 	int error;
1630 
1631 	switch (cmd) {
1632 	/*
1633 	 * Modem commands.
1634 	 * The SER_* and TIOCM_* flags are the same, but one bit
1635 	 * shifted. I don't know why.
1636 	 */
1637 	case TIOCSDTR:
1638 		ttydevsw_modem(tp, SER_DTR, 0);
1639 		return (0);
1640 	case TIOCCDTR:
1641 		ttydevsw_modem(tp, 0, SER_DTR);
1642 		return (0);
1643 	case TIOCMSET: {
1644 		int bits = *(int *)data;
1645 		ttydevsw_modem(tp,
1646 		    (bits & (TIOCM_DTR | TIOCM_RTS)) >> 1,
1647 		    ((~bits) & (TIOCM_DTR | TIOCM_RTS)) >> 1);
1648 		return (0);
1649 	}
1650 	case TIOCMBIS: {
1651 		int bits = *(int *)data;
1652 		ttydevsw_modem(tp, (bits & (TIOCM_DTR | TIOCM_RTS)) >> 1, 0);
1653 		return (0);
1654 	}
1655 	case TIOCMBIC: {
1656 		int bits = *(int *)data;
1657 		ttydevsw_modem(tp, 0, (bits & (TIOCM_DTR | TIOCM_RTS)) >> 1);
1658 		return (0);
1659 	}
1660 	case TIOCMGET:
1661 		*(int *)data = TIOCM_LE + (ttydevsw_modem(tp, 0, 0) << 1);
1662 		return (0);
1663 
1664 	case FIOASYNC:
1665 		if (*(int *)data)
1666 			tp->t_flags |= TF_ASYNC;
1667 		else
1668 			tp->t_flags &= ~TF_ASYNC;
1669 		return (0);
1670 	case FIONBIO:
1671 		/* This device supports non-blocking operation. */
1672 		return (0);
1673 	case FIONREAD:
1674 		*(int *)data = ttyinq_bytescanonicalized(&tp->t_inq);
1675 		return (0);
1676 	case FIONWRITE:
1677 	case TIOCOUTQ:
1678 		*(int *)data = ttyoutq_bytesused(&tp->t_outq);
1679 		return (0);
1680 	case FIOSETOWN:
1681 		if (tp->t_session != NULL && !tty_is_ctty(tp, td->td_proc))
1682 			/* Not allowed to set ownership. */
1683 			return (ENOTTY);
1684 
1685 		/* Temporarily unlock the TTY to set ownership. */
1686 		tty_unlock(tp);
1687 		error = fsetown(*(int *)data, &tp->t_sigio);
1688 		tty_lock(tp);
1689 		return (error);
1690 	case FIOGETOWN:
1691 		if (tp->t_session != NULL && !tty_is_ctty(tp, td->td_proc))
1692 			/* Not allowed to set ownership. */
1693 			return (ENOTTY);
1694 
1695 		/* Get ownership. */
1696 		*(int *)data = fgetown(&tp->t_sigio);
1697 		return (0);
1698 	case TIOCGETA:
1699 		/* Obtain terminal flags through tcgetattr(). */
1700 		*(struct termios*)data = tp->t_termios;
1701 		return (0);
1702 	case TIOCSETA:
1703 	case TIOCSETAW:
1704 	case TIOCSETAF: {
1705 		struct termios *t = data;
1706 
1707 		/*
1708 		 * Who makes up these funny rules? According to POSIX,
1709 		 * input baud rate is set equal to the output baud rate
1710 		 * when zero.
1711 		 */
1712 		if (t->c_ispeed == 0)
1713 			t->c_ispeed = t->c_ospeed;
1714 
1715 		/* Discard any unsupported bits. */
1716 		t->c_iflag &= TTYSUP_IFLAG;
1717 		t->c_oflag &= TTYSUP_OFLAG;
1718 		t->c_lflag &= TTYSUP_LFLAG;
1719 		t->c_cflag &= TTYSUP_CFLAG;
1720 
1721 		/* Set terminal flags through tcsetattr(). */
1722 		if (cmd == TIOCSETAW || cmd == TIOCSETAF) {
1723 			error = tty_drain(tp, 0);
1724 			if (error)
1725 				return (error);
1726 			if (cmd == TIOCSETAF)
1727 				tty_flush(tp, FREAD);
1728 		}
1729 
1730 		/*
1731 		 * Only call param() when the flags really change.
1732 		 */
1733 		if ((t->c_cflag & CIGNORE) == 0 &&
1734 		    (tp->t_termios.c_cflag != t->c_cflag ||
1735 		    ((tp->t_termios.c_iflag ^ t->c_iflag) &
1736 		    (IXON|IXOFF|IXANY)) ||
1737 		    tp->t_termios.c_ispeed != t->c_ispeed ||
1738 		    tp->t_termios.c_ospeed != t->c_ospeed)) {
1739 			error = ttydevsw_param(tp, t);
1740 			if (error)
1741 				return (error);
1742 
1743 			/* XXX: CLOCAL? */
1744 
1745 			tp->t_termios.c_cflag = t->c_cflag & ~CIGNORE;
1746 			tp->t_termios.c_ispeed = t->c_ispeed;
1747 			tp->t_termios.c_ospeed = t->c_ospeed;
1748 
1749 			/* Baud rate has changed - update watermarks. */
1750 			error = tty_watermarks(tp);
1751 			if (error)
1752 				return (error);
1753 		}
1754 
1755 		/* Copy new non-device driver parameters. */
1756 		tp->t_termios.c_iflag = t->c_iflag;
1757 		tp->t_termios.c_oflag = t->c_oflag;
1758 		tp->t_termios.c_lflag = t->c_lflag;
1759 		memcpy(&tp->t_termios.c_cc, t->c_cc, sizeof t->c_cc);
1760 
1761 		ttydisc_optimize(tp);
1762 
1763 		if ((t->c_lflag & ICANON) == 0) {
1764 			/*
1765 			 * When in non-canonical mode, wake up all
1766 			 * readers. Canonicalize any partial input. VMIN
1767 			 * and VTIME could also be adjusted.
1768 			 */
1769 			ttyinq_canonicalize(&tp->t_inq);
1770 			tty_wakeup(tp, FREAD);
1771 		}
1772 
1773 		/*
1774 		 * For packet mode: notify the PTY consumer that VSTOP
1775 		 * and VSTART may have been changed.
1776 		 */
1777 		if (tp->t_termios.c_iflag & IXON &&
1778 		    tp->t_termios.c_cc[VSTOP] == CTRL('S') &&
1779 		    tp->t_termios.c_cc[VSTART] == CTRL('Q'))
1780 			ttydevsw_pktnotify(tp, TIOCPKT_DOSTOP);
1781 		else
1782 			ttydevsw_pktnotify(tp, TIOCPKT_NOSTOP);
1783 		return (0);
1784 	}
1785 	case TIOCGETD:
1786 		/* For compatibility - we only support TTYDISC. */
1787 		*(int *)data = TTYDISC;
1788 		return (0);
1789 	case TIOCGPGRP:
1790 		if (!tty_is_ctty(tp, td->td_proc))
1791 			return (ENOTTY);
1792 
1793 		if (tp->t_pgrp != NULL)
1794 			*(int *)data = tp->t_pgrp->pg_id;
1795 		else
1796 			*(int *)data = NO_PID;
1797 		return (0);
1798 	case TIOCGSID:
1799 		if (!tty_is_ctty(tp, td->td_proc))
1800 			return (ENOTTY);
1801 
1802 		MPASS(tp->t_session);
1803 		*(int *)data = tp->t_session->s_sid;
1804 		return (0);
1805 	case TIOCNOTTY:
1806 		return (tty_drop_ctty(tp, td->td_proc));
1807 	case TIOCSCTTY: {
1808 		struct proc *p = td->td_proc;
1809 
1810 		/* XXX: This looks awful. */
1811 		tty_unlock(tp);
1812 		sx_xlock(&proctree_lock);
1813 		tty_lock(tp);
1814 
1815 		if (!SESS_LEADER(p)) {
1816 			/* Only the session leader may do this. */
1817 			sx_xunlock(&proctree_lock);
1818 			return (EPERM);
1819 		}
1820 
1821 		if (tp->t_session != NULL && tp->t_session == p->p_session) {
1822 			/* This is already our controlling TTY. */
1823 			sx_xunlock(&proctree_lock);
1824 			return (0);
1825 		}
1826 
1827 		if (p->p_session->s_ttyp != NULL ||
1828 		    (tp->t_session != NULL && tp->t_session->s_ttyvp != NULL &&
1829 		    tp->t_session->s_ttyvp->v_type != VBAD)) {
1830 			/*
1831 			 * There is already a relation between a TTY and
1832 			 * a session, or the caller is not the session
1833 			 * leader.
1834 			 *
1835 			 * Allow the TTY to be stolen when the vnode is
1836 			 * invalid, but the reference to the TTY is
1837 			 * still active.  This allows immediate reuse of
1838 			 * TTYs of which the session leader has been
1839 			 * killed or the TTY revoked.
1840 			 */
1841 			sx_xunlock(&proctree_lock);
1842 			return (EPERM);
1843 		}
1844 
1845 		/* Connect the session to the TTY. */
1846 		tp->t_session = p->p_session;
1847 		tp->t_session->s_ttyp = tp;
1848 		tp->t_sessioncnt++;
1849 
1850 		/* Assign foreground process group. */
1851 		tp->t_pgrp = p->p_pgrp;
1852 		PROC_LOCK(p);
1853 		p->p_flag |= P_CONTROLT;
1854 		PROC_UNLOCK(p);
1855 
1856 		sx_xunlock(&proctree_lock);
1857 		return (0);
1858 	}
1859 	case TIOCSPGRP: {
1860 		struct pgrp *pg;
1861 
1862 		/*
1863 		 * XXX: Temporarily unlock the TTY to locate the process
1864 		 * group. This code would be lot nicer if we would ever
1865 		 * decompose proctree_lock.
1866 		 */
1867 		tty_unlock(tp);
1868 		sx_slock(&proctree_lock);
1869 		pg = pgfind(*(int *)data);
1870 		if (pg != NULL)
1871 			PGRP_UNLOCK(pg);
1872 		if (pg == NULL || pg->pg_session != td->td_proc->p_session) {
1873 			sx_sunlock(&proctree_lock);
1874 			tty_lock(tp);
1875 			return (EPERM);
1876 		}
1877 		tty_lock(tp);
1878 
1879 		/*
1880 		 * Determine if this TTY is the controlling TTY after
1881 		 * relocking the TTY.
1882 		 */
1883 		if (!tty_is_ctty(tp, td->td_proc)) {
1884 			sx_sunlock(&proctree_lock);
1885 			return (ENOTTY);
1886 		}
1887 		tp->t_pgrp = pg;
1888 		sx_sunlock(&proctree_lock);
1889 
1890 		/* Wake up the background process groups. */
1891 		cv_broadcast(&tp->t_bgwait);
1892 		return (0);
1893 	}
1894 	case TIOCFLUSH: {
1895 		int flags = *(int *)data;
1896 
1897 		if (flags == 0)
1898 			flags = (FREAD|FWRITE);
1899 		else
1900 			flags &= (FREAD|FWRITE);
1901 		tty_flush(tp, flags);
1902 		return (0);
1903 	}
1904 	case TIOCDRAIN:
1905 		/* Drain TTY output. */
1906 		return tty_drain(tp, 0);
1907 	case TIOCGDRAINWAIT:
1908 		*(int *)data = tp->t_drainwait;
1909 		return (0);
1910 	case TIOCSDRAINWAIT:
1911 		error = priv_check(td, PRIV_TTY_DRAINWAIT);
1912 		if (error == 0)
1913 			tp->t_drainwait = *(int *)data;
1914 		return (error);
1915 	case TIOCCONS:
1916 		/* Set terminal as console TTY. */
1917 		if (*(int *)data) {
1918 			error = priv_check(td, PRIV_TTY_CONSOLE);
1919 			if (error)
1920 				return (error);
1921 
1922 			/*
1923 			 * XXX: constty should really need to be locked!
1924 			 * XXX: allow disconnected constty's to be stolen!
1925 			 */
1926 
1927 			if (constty == tp)
1928 				return (0);
1929 			if (constty != NULL)
1930 				return (EBUSY);
1931 
1932 			tty_unlock(tp);
1933 			constty_set(tp);
1934 			tty_lock(tp);
1935 		} else if (constty == tp) {
1936 			constty_clear();
1937 		}
1938 		return (0);
1939 	case TIOCGWINSZ:
1940 		/* Obtain window size. */
1941 		*(struct winsize*)data = tp->t_winsize;
1942 		return (0);
1943 	case TIOCSWINSZ:
1944 		/* Set window size. */
1945 		tty_set_winsize(tp, data);
1946 		return (0);
1947 	case TIOCEXCL:
1948 		tp->t_flags |= TF_EXCLUDE;
1949 		return (0);
1950 	case TIOCNXCL:
1951 		tp->t_flags &= ~TF_EXCLUDE;
1952 		return (0);
1953 	case TIOCSTOP:
1954 		tp->t_flags |= TF_STOPPED;
1955 		ttydevsw_pktnotify(tp, TIOCPKT_STOP);
1956 		return (0);
1957 	case TIOCSTART:
1958 		tp->t_flags &= ~TF_STOPPED;
1959 		tp->t_termios.c_lflag &= ~FLUSHO;
1960 		ttydevsw_outwakeup(tp);
1961 		ttydevsw_pktnotify(tp, TIOCPKT_START);
1962 		return (0);
1963 	case TIOCSTAT:
1964 		tty_info(tp);
1965 		return (0);
1966 	case TIOCSTI:
1967 		if ((fflag & FREAD) == 0 && priv_check(td, PRIV_TTY_STI))
1968 			return (EPERM);
1969 		if (!tty_is_ctty(tp, td->td_proc) &&
1970 		    priv_check(td, PRIV_TTY_STI))
1971 			return (EACCES);
1972 		ttydisc_rint(tp, *(char *)data, 0);
1973 		ttydisc_rint_done(tp);
1974 		return (0);
1975 	}
1976 
1977 #ifdef COMPAT_43TTY
1978 	return tty_ioctl_compat(tp, cmd, data, fflag, td);
1979 #else /* !COMPAT_43TTY */
1980 	return (ENOIOCTL);
1981 #endif /* COMPAT_43TTY */
1982 }
1983 
1984 int
1985 tty_ioctl(struct tty *tp, u_long cmd, void *data, int fflag, struct thread *td)
1986 {
1987 	int error;
1988 
1989 	tty_assert_locked(tp);
1990 
1991 	if (tty_gone(tp))
1992 		return (ENXIO);
1993 
1994 	error = ttydevsw_ioctl(tp, cmd, data, td);
1995 	if (error == ENOIOCTL)
1996 		error = tty_generic_ioctl(tp, cmd, data, fflag, td);
1997 
1998 	return (error);
1999 }
2000 
2001 dev_t
2002 tty_udev(struct tty *tp)
2003 {
2004 
2005 	if (tp->t_dev)
2006 		return (dev2udev(tp->t_dev));
2007 	else
2008 		return (NODEV);
2009 }
2010 
2011 int
2012 tty_checkoutq(struct tty *tp)
2013 {
2014 
2015 	/* 256 bytes should be enough to print a log message. */
2016 	return (ttyoutq_bytesleft(&tp->t_outq) >= 256);
2017 }
2018 
2019 void
2020 tty_hiwat_in_block(struct tty *tp)
2021 {
2022 
2023 	if ((tp->t_flags & TF_HIWAT_IN) == 0 &&
2024 	    tp->t_termios.c_iflag & IXOFF &&
2025 	    tp->t_termios.c_cc[VSTOP] != _POSIX_VDISABLE) {
2026 		/*
2027 		 * Input flow control. Only enter the high watermark when we
2028 		 * can successfully store the VSTOP character.
2029 		 */
2030 		if (ttyoutq_write_nofrag(&tp->t_outq,
2031 		    &tp->t_termios.c_cc[VSTOP], 1) == 0)
2032 			tp->t_flags |= TF_HIWAT_IN;
2033 	} else {
2034 		/* No input flow control. */
2035 		tp->t_flags |= TF_HIWAT_IN;
2036 	}
2037 }
2038 
2039 void
2040 tty_hiwat_in_unblock(struct tty *tp)
2041 {
2042 
2043 	if (tp->t_flags & TF_HIWAT_IN &&
2044 	    tp->t_termios.c_iflag & IXOFF &&
2045 	    tp->t_termios.c_cc[VSTART] != _POSIX_VDISABLE) {
2046 		/*
2047 		 * Input flow control. Only leave the high watermark when we
2048 		 * can successfully store the VSTART character.
2049 		 */
2050 		if (ttyoutq_write_nofrag(&tp->t_outq,
2051 		    &tp->t_termios.c_cc[VSTART], 1) == 0)
2052 			tp->t_flags &= ~TF_HIWAT_IN;
2053 	} else {
2054 		/* No input flow control. */
2055 		tp->t_flags &= ~TF_HIWAT_IN;
2056 	}
2057 
2058 	if (!tty_gone(tp))
2059 		ttydevsw_inwakeup(tp);
2060 }
2061 
2062 /*
2063  * TTY hooks interface.
2064  */
2065 
2066 static int
2067 ttyhook_defrint(struct tty *tp, char c, int flags)
2068 {
2069 
2070 	if (ttyhook_rint_bypass(tp, &c, 1) != 1)
2071 		return (-1);
2072 
2073 	return (0);
2074 }
2075 
2076 int
2077 ttyhook_register(struct tty **rtp, struct proc *p, int fd, struct ttyhook *th,
2078     void *softc)
2079 {
2080 	struct tty *tp;
2081 	struct file *fp;
2082 	struct cdev *dev;
2083 	struct cdevsw *cdp;
2084 	struct filedesc *fdp;
2085 	cap_rights_t rights;
2086 	int error, ref;
2087 
2088 	/* Validate the file descriptor. */
2089 	fdp = p->p_fd;
2090 	error = fget_unlocked(fdp, fd, cap_rights_init_one(&rights, CAP_TTYHOOK),
2091 	    &fp);
2092 	if (error != 0)
2093 		return (error);
2094 	if (fp->f_ops == &badfileops) {
2095 		error = EBADF;
2096 		goto done1;
2097 	}
2098 
2099 	/*
2100 	 * Make sure the vnode is bound to a character device.
2101 	 * Unlocked check for the vnode type is ok there, because we
2102 	 * only shall prevent calling devvn_refthread on the file that
2103 	 * never has been opened over a character device.
2104 	 */
2105 	if (fp->f_type != DTYPE_VNODE || fp->f_vnode->v_type != VCHR) {
2106 		error = EINVAL;
2107 		goto done1;
2108 	}
2109 
2110 	/* Make sure it is a TTY. */
2111 	cdp = devvn_refthread(fp->f_vnode, &dev, &ref);
2112 	if (cdp == NULL) {
2113 		error = ENXIO;
2114 		goto done1;
2115 	}
2116 	if (dev != fp->f_data) {
2117 		error = ENXIO;
2118 		goto done2;
2119 	}
2120 	if (cdp != &ttydev_cdevsw) {
2121 		error = ENOTTY;
2122 		goto done2;
2123 	}
2124 	tp = dev->si_drv1;
2125 
2126 	/* Try to attach the hook to the TTY. */
2127 	error = EBUSY;
2128 	tty_lock(tp);
2129 	MPASS((tp->t_hook == NULL) == ((tp->t_flags & TF_HOOK) == 0));
2130 	if (tp->t_flags & TF_HOOK)
2131 		goto done3;
2132 
2133 	tp->t_flags |= TF_HOOK;
2134 	tp->t_hook = th;
2135 	tp->t_hooksoftc = softc;
2136 	*rtp = tp;
2137 	error = 0;
2138 
2139 	/* Maybe we can switch into bypass mode now. */
2140 	ttydisc_optimize(tp);
2141 
2142 	/* Silently convert rint() calls to rint_bypass() when possible. */
2143 	if (!ttyhook_hashook(tp, rint) && ttyhook_hashook(tp, rint_bypass))
2144 		th->th_rint = ttyhook_defrint;
2145 
2146 done3:	tty_unlock(tp);
2147 done2:	dev_relthread(dev, ref);
2148 done1:	fdrop(fp, curthread);
2149 	return (error);
2150 }
2151 
2152 void
2153 ttyhook_unregister(struct tty *tp)
2154 {
2155 
2156 	tty_assert_locked(tp);
2157 	MPASS(tp->t_flags & TF_HOOK);
2158 
2159 	/* Disconnect the hook. */
2160 	tp->t_flags &= ~TF_HOOK;
2161 	tp->t_hook = NULL;
2162 
2163 	/* Maybe we need to leave bypass mode. */
2164 	ttydisc_optimize(tp);
2165 
2166 	/* Maybe deallocate the TTY as well. */
2167 	tty_rel_free(tp);
2168 }
2169 
2170 /*
2171  * /dev/console handling.
2172  */
2173 
2174 static int
2175 ttyconsdev_open(struct cdev *dev, int oflags, int devtype, struct thread *td)
2176 {
2177 	struct tty *tp;
2178 
2179 	/* System has no console device. */
2180 	if (dev_console_filename == NULL)
2181 		return (ENXIO);
2182 
2183 	/* Look up corresponding TTY by device name. */
2184 	sx_slock(&tty_list_sx);
2185 	TAILQ_FOREACH(tp, &tty_list, t_list) {
2186 		if (strcmp(dev_console_filename, tty_devname(tp)) == 0) {
2187 			dev_console->si_drv1 = tp;
2188 			break;
2189 		}
2190 	}
2191 	sx_sunlock(&tty_list_sx);
2192 
2193 	/* System console has no TTY associated. */
2194 	if (dev_console->si_drv1 == NULL)
2195 		return (ENXIO);
2196 
2197 	return (ttydev_open(dev, oflags, devtype, td));
2198 }
2199 
2200 static int
2201 ttyconsdev_write(struct cdev *dev, struct uio *uio, int ioflag)
2202 {
2203 
2204 	log_console(uio);
2205 
2206 	return (ttydev_write(dev, uio, ioflag));
2207 }
2208 
2209 /*
2210  * /dev/console is a little different than normal TTY's.  When opened,
2211  * it determines which TTY to use.  When data gets written to it, it
2212  * will be logged in the kernel message buffer.
2213  */
2214 static struct cdevsw ttyconsdev_cdevsw = {
2215 	.d_version	= D_VERSION,
2216 	.d_open		= ttyconsdev_open,
2217 	.d_close	= ttydev_close,
2218 	.d_read		= ttydev_read,
2219 	.d_write	= ttyconsdev_write,
2220 	.d_ioctl	= ttydev_ioctl,
2221 	.d_kqfilter	= ttydev_kqfilter,
2222 	.d_poll		= ttydev_poll,
2223 	.d_mmap		= ttydev_mmap,
2224 	.d_name		= "ttyconsdev",
2225 	.d_flags	= D_TTY,
2226 };
2227 
2228 static void
2229 ttyconsdev_init(void *unused __unused)
2230 {
2231 
2232 	dev_console = make_dev_credf(MAKEDEV_ETERNAL, &ttyconsdev_cdevsw, 0,
2233 	    NULL, UID_ROOT, GID_WHEEL, 0600, "console");
2234 }
2235 
2236 SYSINIT(tty, SI_SUB_DRIVERS, SI_ORDER_FIRST, ttyconsdev_init, NULL);
2237 
2238 void
2239 ttyconsdev_select(const char *name)
2240 {
2241 
2242 	dev_console_filename = name;
2243 }
2244 
2245 /*
2246  * Debugging routines.
2247  */
2248 
2249 #include "opt_ddb.h"
2250 #ifdef DDB
2251 #include <ddb/ddb.h>
2252 #include <ddb/db_sym.h>
2253 
2254 static const struct {
2255 	int flag;
2256 	char val;
2257 } ttystates[] = {
2258 #if 0
2259 	{ TF_NOPREFIX,		'N' },
2260 #endif
2261 	{ TF_INITLOCK,		'I' },
2262 	{ TF_CALLOUT,		'C' },
2263 
2264 	/* Keep these together -> 'Oi' and 'Oo'. */
2265 	{ TF_OPENED,		'O' },
2266 	{ TF_OPENED_IN,		'i' },
2267 	{ TF_OPENED_OUT,	'o' },
2268 	{ TF_OPENED_CONS,	'c' },
2269 
2270 	{ TF_GONE,		'G' },
2271 	{ TF_OPENCLOSE,		'B' },
2272 	{ TF_ASYNC,		'Y' },
2273 	{ TF_LITERAL,		'L' },
2274 
2275 	/* Keep these together -> 'Hi' and 'Ho'. */
2276 	{ TF_HIWAT,		'H' },
2277 	{ TF_HIWAT_IN,		'i' },
2278 	{ TF_HIWAT_OUT,		'o' },
2279 
2280 	{ TF_STOPPED,		'S' },
2281 	{ TF_EXCLUDE,		'X' },
2282 	{ TF_BYPASS,		'l' },
2283 	{ TF_ZOMBIE,		'Z' },
2284 	{ TF_HOOK,		's' },
2285 
2286 	/* Keep these together -> 'bi' and 'bo'. */
2287 	{ TF_BUSY,		'b' },
2288 	{ TF_BUSY_IN,		'i' },
2289 	{ TF_BUSY_OUT,		'o' },
2290 
2291 	{ 0,			'\0'},
2292 };
2293 
2294 #define	TTY_FLAG_BITS \
2295 	"\20\1NOPREFIX\2INITLOCK\3CALLOUT\4OPENED_IN" \
2296 	"\5OPENED_OUT\6OPENED_CONS\7GONE\10OPENCLOSE" \
2297 	"\11ASYNC\12LITERAL\13HIWAT_IN\14HIWAT_OUT" \
2298 	"\15STOPPED\16EXCLUDE\17BYPASS\20ZOMBIE" \
2299 	"\21HOOK\22BUSY_IN\23BUSY_OUT"
2300 
2301 #define DB_PRINTSYM(name, addr) \
2302 	db_printf("%s  " #name ": ", sep); \
2303 	db_printsym((db_addr_t) addr, DB_STGY_ANY); \
2304 	db_printf("\n");
2305 
2306 static void
2307 _db_show_devsw(const char *sep, const struct ttydevsw *tsw)
2308 {
2309 
2310 	db_printf("%sdevsw: ", sep);
2311 	db_printsym((db_addr_t)tsw, DB_STGY_ANY);
2312 	db_printf(" (%p)\n", tsw);
2313 	DB_PRINTSYM(open, tsw->tsw_open);
2314 	DB_PRINTSYM(close, tsw->tsw_close);
2315 	DB_PRINTSYM(outwakeup, tsw->tsw_outwakeup);
2316 	DB_PRINTSYM(inwakeup, tsw->tsw_inwakeup);
2317 	DB_PRINTSYM(ioctl, tsw->tsw_ioctl);
2318 	DB_PRINTSYM(param, tsw->tsw_param);
2319 	DB_PRINTSYM(modem, tsw->tsw_modem);
2320 	DB_PRINTSYM(mmap, tsw->tsw_mmap);
2321 	DB_PRINTSYM(pktnotify, tsw->tsw_pktnotify);
2322 	DB_PRINTSYM(free, tsw->tsw_free);
2323 }
2324 
2325 static void
2326 _db_show_hooks(const char *sep, const struct ttyhook *th)
2327 {
2328 
2329 	db_printf("%shook: ", sep);
2330 	db_printsym((db_addr_t)th, DB_STGY_ANY);
2331 	db_printf(" (%p)\n", th);
2332 	if (th == NULL)
2333 		return;
2334 	DB_PRINTSYM(rint, th->th_rint);
2335 	DB_PRINTSYM(rint_bypass, th->th_rint_bypass);
2336 	DB_PRINTSYM(rint_done, th->th_rint_done);
2337 	DB_PRINTSYM(rint_poll, th->th_rint_poll);
2338 	DB_PRINTSYM(getc_inject, th->th_getc_inject);
2339 	DB_PRINTSYM(getc_capture, th->th_getc_capture);
2340 	DB_PRINTSYM(getc_poll, th->th_getc_poll);
2341 	DB_PRINTSYM(close, th->th_close);
2342 }
2343 
2344 static void
2345 _db_show_termios(const char *name, const struct termios *t)
2346 {
2347 
2348 	db_printf("%s: iflag 0x%x oflag 0x%x cflag 0x%x "
2349 	    "lflag 0x%x ispeed %u ospeed %u\n", name,
2350 	    t->c_iflag, t->c_oflag, t->c_cflag, t->c_lflag,
2351 	    t->c_ispeed, t->c_ospeed);
2352 }
2353 
2354 /* DDB command to show TTY statistics. */
2355 DB_SHOW_COMMAND(tty, db_show_tty)
2356 {
2357 	struct tty *tp;
2358 
2359 	if (!have_addr) {
2360 		db_printf("usage: show tty <addr>\n");
2361 		return;
2362 	}
2363 	tp = (struct tty *)addr;
2364 
2365 	db_printf("%p: %s\n", tp, tty_devname(tp));
2366 	db_printf("\tmtx: %p\n", tp->t_mtx);
2367 	db_printf("\tflags: 0x%b\n", tp->t_flags, TTY_FLAG_BITS);
2368 	db_printf("\trevokecnt: %u\n", tp->t_revokecnt);
2369 
2370 	/* Buffering mechanisms. */
2371 	db_printf("\tinq: %p begin %u linestart %u reprint %u end %u "
2372 	    "nblocks %u quota %u\n", &tp->t_inq, tp->t_inq.ti_begin,
2373 	    tp->t_inq.ti_linestart, tp->t_inq.ti_reprint, tp->t_inq.ti_end,
2374 	    tp->t_inq.ti_nblocks, tp->t_inq.ti_quota);
2375 	db_printf("\toutq: %p begin %u end %u nblocks %u quota %u\n",
2376 	    &tp->t_outq, tp->t_outq.to_begin, tp->t_outq.to_end,
2377 	    tp->t_outq.to_nblocks, tp->t_outq.to_quota);
2378 	db_printf("\tinlow: %zu\n", tp->t_inlow);
2379 	db_printf("\toutlow: %zu\n", tp->t_outlow);
2380 	_db_show_termios("\ttermios", &tp->t_termios);
2381 	db_printf("\twinsize: row %u col %u xpixel %u ypixel %u\n",
2382 	    tp->t_winsize.ws_row, tp->t_winsize.ws_col,
2383 	    tp->t_winsize.ws_xpixel, tp->t_winsize.ws_ypixel);
2384 	db_printf("\tcolumn: %u\n", tp->t_column);
2385 	db_printf("\twritepos: %u\n", tp->t_writepos);
2386 	db_printf("\tcompatflags: 0x%x\n", tp->t_compatflags);
2387 
2388 	/* Init/lock-state devices. */
2389 	_db_show_termios("\ttermios_init_in", &tp->t_termios_init_in);
2390 	_db_show_termios("\ttermios_init_out", &tp->t_termios_init_out);
2391 	_db_show_termios("\ttermios_lock_in", &tp->t_termios_lock_in);
2392 	_db_show_termios("\ttermios_lock_out", &tp->t_termios_lock_out);
2393 
2394 	/* Hooks */
2395 	_db_show_devsw("\t", tp->t_devsw);
2396 	_db_show_hooks("\t", tp->t_hook);
2397 
2398 	/* Process info. */
2399 	db_printf("\tpgrp: %p gid %d\n", tp->t_pgrp,
2400 	    tp->t_pgrp ? tp->t_pgrp->pg_id : 0);
2401 	db_printf("\tsession: %p", tp->t_session);
2402 	if (tp->t_session != NULL)
2403 	    db_printf(" count %u leader %p tty %p sid %d login %s",
2404 		tp->t_session->s_count, tp->t_session->s_leader,
2405 		tp->t_session->s_ttyp, tp->t_session->s_sid,
2406 		tp->t_session->s_login);
2407 	db_printf("\n");
2408 	db_printf("\tsessioncnt: %u\n", tp->t_sessioncnt);
2409 	db_printf("\tdevswsoftc: %p\n", tp->t_devswsoftc);
2410 	db_printf("\thooksoftc: %p\n", tp->t_hooksoftc);
2411 	db_printf("\tdev: %p\n", tp->t_dev);
2412 }
2413 
2414 /* DDB command to list TTYs. */
2415 DB_SHOW_ALL_COMMAND(ttys, db_show_all_ttys)
2416 {
2417 	struct tty *tp;
2418 	size_t isiz, osiz;
2419 	int i, j;
2420 
2421 	/* Make the output look like `pstat -t'. */
2422 	db_printf("PTR        ");
2423 #if defined(__LP64__)
2424 	db_printf("        ");
2425 #endif
2426 	db_printf("      LINE   INQ  CAN  LIN  LOW  OUTQ  USE  LOW   "
2427 	    "COL  SESS  PGID STATE\n");
2428 
2429 	TAILQ_FOREACH(tp, &tty_list, t_list) {
2430 		isiz = tp->t_inq.ti_nblocks * TTYINQ_DATASIZE;
2431 		osiz = tp->t_outq.to_nblocks * TTYOUTQ_DATASIZE;
2432 
2433 		db_printf("%p %10s %5zu %4u %4u %4zu %5zu %4u %4zu %5u %5d "
2434 		    "%5d ", tp, tty_devname(tp), isiz,
2435 		    tp->t_inq.ti_linestart - tp->t_inq.ti_begin,
2436 		    tp->t_inq.ti_end - tp->t_inq.ti_linestart,
2437 		    isiz - tp->t_inlow, osiz,
2438 		    tp->t_outq.to_end - tp->t_outq.to_begin,
2439 		    osiz - tp->t_outlow, MIN(tp->t_column, 99999),
2440 		    tp->t_session ? tp->t_session->s_sid : 0,
2441 		    tp->t_pgrp ? tp->t_pgrp->pg_id : 0);
2442 
2443 		/* Flag bits. */
2444 		for (i = j = 0; ttystates[i].flag; i++)
2445 			if (tp->t_flags & ttystates[i].flag) {
2446 				db_printf("%c", ttystates[i].val);
2447 				j++;
2448 			}
2449 		if (j == 0)
2450 			db_printf("-");
2451 		db_printf("\n");
2452 	}
2453 }
2454 #endif /* DDB */
2455