xref: /freebsd/sys/kern/tty.c (revision f2d48b5e2c3b45850585e4d7aee324fe148afbf2)
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 = td->td_proc;
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 	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 
478 		/*
479 		 * pg may no longer be our process group.
480 		 * Re-check after locking process group.
481 		 */
482 		PROC_LOCK(p);
483 		if (p->p_pgrp != pg) {
484 			PROC_UNLOCK(p);
485 			PGRP_UNLOCK(pg);
486 			continue;
487 		}
488 
489 		PROC_UNLOCK(p);
490 		pgsignal(pg, ksi.ksi_signo, 1, &ksi);
491 		PGRP_UNLOCK(pg);
492 
493 		error = tty_wait(tp, &tp->t_bgwait);
494 		if (error)
495 			return (error);
496 	}
497 }
498 
499 static int
500 ttydev_read(struct cdev *dev, struct uio *uio, int ioflag)
501 {
502 	struct tty *tp = dev->si_drv1;
503 	int error;
504 
505 	error = ttydev_enter(tp);
506 	if (error)
507 		goto done;
508 	error = ttydisc_read(tp, uio, ioflag);
509 	tty_unlock(tp);
510 
511 	/*
512 	 * The read() call should not throw an error when the device is
513 	 * being destroyed. Silently convert it to an EOF.
514 	 */
515 done:	if (error == ENXIO)
516 		error = 0;
517 	return (error);
518 }
519 
520 static int
521 ttydev_write(struct cdev *dev, struct uio *uio, int ioflag)
522 {
523 	struct tty *tp = dev->si_drv1;
524 	int error;
525 
526 	error = ttydev_enter(tp);
527 	if (error)
528 		return (error);
529 
530 	if (tp->t_termios.c_lflag & TOSTOP) {
531 		error = tty_wait_background(tp, curthread, SIGTTOU);
532 		if (error)
533 			goto done;
534 	}
535 
536 	if (ioflag & IO_NDELAY && tp->t_flags & TF_BUSY_OUT) {
537 		/* Allow non-blocking writes to bypass serialization. */
538 		error = ttydisc_write(tp, uio, ioflag);
539 	} else {
540 		/* Serialize write() calls. */
541 		while (tp->t_flags & TF_BUSY_OUT) {
542 			error = tty_wait(tp, &tp->t_outserwait);
543 			if (error)
544 				goto done;
545 		}
546 
547 		tp->t_flags |= TF_BUSY_OUT;
548 		error = ttydisc_write(tp, uio, ioflag);
549 		tp->t_flags &= ~TF_BUSY_OUT;
550 		cv_signal(&tp->t_outserwait);
551 	}
552 
553 done:	tty_unlock(tp);
554 	return (error);
555 }
556 
557 static int
558 ttydev_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int fflag,
559     struct thread *td)
560 {
561 	struct tty *tp = dev->si_drv1;
562 	int error;
563 
564 	error = ttydev_enter(tp);
565 	if (error)
566 		return (error);
567 
568 	switch (cmd) {
569 	case TIOCCBRK:
570 	case TIOCCONS:
571 	case TIOCDRAIN:
572 	case TIOCEXCL:
573 	case TIOCFLUSH:
574 	case TIOCNXCL:
575 	case TIOCSBRK:
576 	case TIOCSCTTY:
577 	case TIOCSETA:
578 	case TIOCSETAF:
579 	case TIOCSETAW:
580 	case TIOCSPGRP:
581 	case TIOCSTART:
582 	case TIOCSTAT:
583 	case TIOCSTI:
584 	case TIOCSTOP:
585 	case TIOCSWINSZ:
586 #if 0
587 	case TIOCSDRAINWAIT:
588 	case TIOCSETD:
589 #endif
590 #ifdef COMPAT_43TTY
591 	case  TIOCLBIC:
592 	case  TIOCLBIS:
593 	case  TIOCLSET:
594 	case  TIOCSETC:
595 	case OTIOCSETD:
596 	case  TIOCSETN:
597 	case  TIOCSETP:
598 	case  TIOCSLTC:
599 #endif /* COMPAT_43TTY */
600 		/*
601 		 * If the ioctl() causes the TTY to be modified, let it
602 		 * wait in the background.
603 		 */
604 		error = tty_wait_background(tp, curthread, SIGTTOU);
605 		if (error)
606 			goto done;
607 	}
608 
609 	if (cmd == TIOCSETA || cmd == TIOCSETAW || cmd == TIOCSETAF) {
610 		struct termios *old = &tp->t_termios;
611 		struct termios *new = (struct termios *)data;
612 		struct termios *lock = TTY_CALLOUT(tp, dev) ?
613 		    &tp->t_termios_lock_out : &tp->t_termios_lock_in;
614 		int cc;
615 
616 		/*
617 		 * Lock state devices.  Just overwrite the values of the
618 		 * commands that are currently in use.
619 		 */
620 		new->c_iflag = (old->c_iflag & lock->c_iflag) |
621 		    (new->c_iflag & ~lock->c_iflag);
622 		new->c_oflag = (old->c_oflag & lock->c_oflag) |
623 		    (new->c_oflag & ~lock->c_oflag);
624 		new->c_cflag = (old->c_cflag & lock->c_cflag) |
625 		    (new->c_cflag & ~lock->c_cflag);
626 		new->c_lflag = (old->c_lflag & lock->c_lflag) |
627 		    (new->c_lflag & ~lock->c_lflag);
628 		for (cc = 0; cc < NCCS; ++cc)
629 			if (lock->c_cc[cc])
630 				new->c_cc[cc] = old->c_cc[cc];
631 		if (lock->c_ispeed)
632 			new->c_ispeed = old->c_ispeed;
633 		if (lock->c_ospeed)
634 			new->c_ospeed = old->c_ospeed;
635 	}
636 
637 	error = tty_ioctl(tp, cmd, data, fflag, td);
638 done:	tty_unlock(tp);
639 
640 	return (error);
641 }
642 
643 static int
644 ttydev_poll(struct cdev *dev, int events, struct thread *td)
645 {
646 	struct tty *tp = dev->si_drv1;
647 	int error, revents = 0;
648 
649 	error = ttydev_enter(tp);
650 	if (error)
651 		return ((events & (POLLIN|POLLRDNORM)) | POLLHUP);
652 
653 	if (events & (POLLIN|POLLRDNORM)) {
654 		/* See if we can read something. */
655 		if (ttydisc_read_poll(tp) > 0)
656 			revents |= events & (POLLIN|POLLRDNORM);
657 	}
658 
659 	if (tp->t_flags & TF_ZOMBIE) {
660 		/* Hangup flag on zombie state. */
661 		revents |= POLLHUP;
662 	} else if (events & (POLLOUT|POLLWRNORM)) {
663 		/* See if we can write something. */
664 		if (ttydisc_write_poll(tp) > 0)
665 			revents |= events & (POLLOUT|POLLWRNORM);
666 	}
667 
668 	if (revents == 0) {
669 		if (events & (POLLIN|POLLRDNORM))
670 			selrecord(td, &tp->t_inpoll);
671 		if (events & (POLLOUT|POLLWRNORM))
672 			selrecord(td, &tp->t_outpoll);
673 	}
674 
675 	tty_unlock(tp);
676 
677 	return (revents);
678 }
679 
680 static int
681 ttydev_mmap(struct cdev *dev, vm_ooffset_t offset, vm_paddr_t *paddr,
682     int nprot, vm_memattr_t *memattr)
683 {
684 	struct tty *tp = dev->si_drv1;
685 	int error;
686 
687 	/* Handle mmap() through the driver. */
688 
689 	error = ttydev_enter(tp);
690 	if (error)
691 		return (-1);
692 	error = ttydevsw_mmap(tp, offset, paddr, nprot, memattr);
693 	tty_unlock(tp);
694 
695 	return (error);
696 }
697 
698 /*
699  * kqueue support.
700  */
701 
702 static void
703 tty_kqops_read_detach(struct knote *kn)
704 {
705 	struct tty *tp = kn->kn_hook;
706 
707 	knlist_remove(&tp->t_inpoll.si_note, kn, 0);
708 }
709 
710 static int
711 tty_kqops_read_event(struct knote *kn, long hint __unused)
712 {
713 	struct tty *tp = kn->kn_hook;
714 
715 	tty_assert_locked(tp);
716 
717 	if (tty_gone(tp) || tp->t_flags & TF_ZOMBIE) {
718 		kn->kn_flags |= EV_EOF;
719 		return (1);
720 	} else {
721 		kn->kn_data = ttydisc_read_poll(tp);
722 		return (kn->kn_data > 0);
723 	}
724 }
725 
726 static void
727 tty_kqops_write_detach(struct knote *kn)
728 {
729 	struct tty *tp = kn->kn_hook;
730 
731 	knlist_remove(&tp->t_outpoll.si_note, kn, 0);
732 }
733 
734 static int
735 tty_kqops_write_event(struct knote *kn, long hint __unused)
736 {
737 	struct tty *tp = kn->kn_hook;
738 
739 	tty_assert_locked(tp);
740 
741 	if (tty_gone(tp)) {
742 		kn->kn_flags |= EV_EOF;
743 		return (1);
744 	} else {
745 		kn->kn_data = ttydisc_write_poll(tp);
746 		return (kn->kn_data > 0);
747 	}
748 }
749 
750 static struct filterops tty_kqops_read = {
751 	.f_isfd = 1,
752 	.f_detach = tty_kqops_read_detach,
753 	.f_event = tty_kqops_read_event,
754 };
755 
756 static struct filterops tty_kqops_write = {
757 	.f_isfd = 1,
758 	.f_detach = tty_kqops_write_detach,
759 	.f_event = tty_kqops_write_event,
760 };
761 
762 static int
763 ttydev_kqfilter(struct cdev *dev, struct knote *kn)
764 {
765 	struct tty *tp = dev->si_drv1;
766 	int error;
767 
768 	error = ttydev_enter(tp);
769 	if (error)
770 		return (error);
771 
772 	switch (kn->kn_filter) {
773 	case EVFILT_READ:
774 		kn->kn_hook = tp;
775 		kn->kn_fop = &tty_kqops_read;
776 		knlist_add(&tp->t_inpoll.si_note, kn, 1);
777 		break;
778 	case EVFILT_WRITE:
779 		kn->kn_hook = tp;
780 		kn->kn_fop = &tty_kqops_write;
781 		knlist_add(&tp->t_outpoll.si_note, kn, 1);
782 		break;
783 	default:
784 		error = EINVAL;
785 		break;
786 	}
787 
788 	tty_unlock(tp);
789 	return (error);
790 }
791 
792 static struct cdevsw ttydev_cdevsw = {
793 	.d_version	= D_VERSION,
794 	.d_open		= ttydev_open,
795 	.d_close	= ttydev_close,
796 	.d_read		= ttydev_read,
797 	.d_write	= ttydev_write,
798 	.d_ioctl	= ttydev_ioctl,
799 	.d_kqfilter	= ttydev_kqfilter,
800 	.d_poll		= ttydev_poll,
801 	.d_mmap		= ttydev_mmap,
802 	.d_name		= "ttydev",
803 	.d_flags	= D_TTY,
804 };
805 
806 /*
807  * Init/lock-state devices
808  */
809 
810 static int
811 ttyil_open(struct cdev *dev, int oflags __unused, int devtype __unused,
812     struct thread *td)
813 {
814 	struct tty *tp;
815 	int error;
816 
817 	tp = dev->si_drv1;
818 	error = 0;
819 	tty_lock(tp);
820 	if (tty_gone(tp))
821 		error = ENODEV;
822 	tty_unlock(tp);
823 
824 	return (error);
825 }
826 
827 static int
828 ttyil_close(struct cdev *dev __unused, int flag __unused, int mode __unused,
829     struct thread *td __unused)
830 {
831 
832 	return (0);
833 }
834 
835 static int
836 ttyil_rdwr(struct cdev *dev __unused, struct uio *uio __unused,
837     int ioflag __unused)
838 {
839 
840 	return (ENODEV);
841 }
842 
843 static int
844 ttyil_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int fflag,
845     struct thread *td)
846 {
847 	struct tty *tp = dev->si_drv1;
848 	int error;
849 
850 	tty_lock(tp);
851 	if (tty_gone(tp)) {
852 		error = ENODEV;
853 		goto done;
854 	}
855 
856 	error = ttydevsw_cioctl(tp, dev2unit(dev), cmd, data, td);
857 	if (error != ENOIOCTL)
858 		goto done;
859 	error = 0;
860 
861 	switch (cmd) {
862 	case TIOCGETA:
863 		/* Obtain terminal flags through tcgetattr(). */
864 		*(struct termios*)data = *(struct termios*)dev->si_drv2;
865 		break;
866 	case TIOCSETA:
867 		/* Set terminal flags through tcsetattr(). */
868 		error = priv_check(td, PRIV_TTY_SETA);
869 		if (error)
870 			break;
871 		*(struct termios*)dev->si_drv2 = *(struct termios*)data;
872 		break;
873 	case TIOCGETD:
874 		*(int *)data = TTYDISC;
875 		break;
876 	case TIOCGWINSZ:
877 		bzero(data, sizeof(struct winsize));
878 		break;
879 	default:
880 		error = ENOTTY;
881 	}
882 
883 done:	tty_unlock(tp);
884 	return (error);
885 }
886 
887 static struct cdevsw ttyil_cdevsw = {
888 	.d_version	= D_VERSION,
889 	.d_open		= ttyil_open,
890 	.d_close	= ttyil_close,
891 	.d_read		= ttyil_rdwr,
892 	.d_write	= ttyil_rdwr,
893 	.d_ioctl	= ttyil_ioctl,
894 	.d_name		= "ttyil",
895 	.d_flags	= D_TTY,
896 };
897 
898 static void
899 tty_init_termios(struct tty *tp)
900 {
901 	struct termios *t = &tp->t_termios_init_in;
902 
903 	t->c_cflag = TTYDEF_CFLAG;
904 	t->c_iflag = TTYDEF_IFLAG;
905 	t->c_lflag = TTYDEF_LFLAG;
906 	t->c_oflag = TTYDEF_OFLAG;
907 	t->c_ispeed = TTYDEF_SPEED;
908 	t->c_ospeed = TTYDEF_SPEED;
909 	memcpy(&t->c_cc, ttydefchars, sizeof ttydefchars);
910 
911 	tp->t_termios_init_out = *t;
912 }
913 
914 void
915 tty_init_console(struct tty *tp, speed_t s)
916 {
917 	struct termios *ti = &tp->t_termios_init_in;
918 	struct termios *to = &tp->t_termios_init_out;
919 
920 	if (s != 0) {
921 		ti->c_ispeed = ti->c_ospeed = s;
922 		to->c_ispeed = to->c_ospeed = s;
923 	}
924 
925 	ti->c_cflag |= CLOCAL;
926 	to->c_cflag |= CLOCAL;
927 }
928 
929 /*
930  * Standard device routine implementations, mostly meant for
931  * pseudo-terminal device drivers. When a driver creates a new terminal
932  * device class, missing routines are patched.
933  */
934 
935 static int
936 ttydevsw_defopen(struct tty *tp __unused)
937 {
938 
939 	return (0);
940 }
941 
942 static void
943 ttydevsw_defclose(struct tty *tp __unused)
944 {
945 
946 }
947 
948 static void
949 ttydevsw_defoutwakeup(struct tty *tp __unused)
950 {
951 
952 	panic("Terminal device has output, while not implemented");
953 }
954 
955 static void
956 ttydevsw_definwakeup(struct tty *tp __unused)
957 {
958 
959 }
960 
961 static int
962 ttydevsw_defioctl(struct tty *tp __unused, u_long cmd __unused,
963     caddr_t data __unused, struct thread *td __unused)
964 {
965 
966 	return (ENOIOCTL);
967 }
968 
969 static int
970 ttydevsw_defcioctl(struct tty *tp __unused, int unit __unused,
971     u_long cmd __unused, caddr_t data __unused, struct thread *td __unused)
972 {
973 
974 	return (ENOIOCTL);
975 }
976 
977 static int
978 ttydevsw_defparam(struct tty *tp __unused, struct termios *t)
979 {
980 
981 	/*
982 	 * Allow the baud rate to be adjusted for pseudo-devices, but at
983 	 * least restrict it to 115200 to prevent excessive buffer
984 	 * usage.  Also disallow 0, to prevent foot shooting.
985 	 */
986 	if (t->c_ispeed < B50)
987 		t->c_ispeed = B50;
988 	else if (t->c_ispeed > B115200)
989 		t->c_ispeed = B115200;
990 	if (t->c_ospeed < B50)
991 		t->c_ospeed = B50;
992 	else if (t->c_ospeed > B115200)
993 		t->c_ospeed = B115200;
994 	t->c_cflag |= CREAD;
995 
996 	return (0);
997 }
998 
999 static int
1000 ttydevsw_defmodem(struct tty *tp __unused, int sigon __unused,
1001     int sigoff __unused)
1002 {
1003 
1004 	/* Simulate a carrier to make the TTY layer happy. */
1005 	return (SER_DCD);
1006 }
1007 
1008 static int
1009 ttydevsw_defmmap(struct tty *tp __unused, vm_ooffset_t offset __unused,
1010     vm_paddr_t *paddr __unused, int nprot __unused,
1011     vm_memattr_t *memattr __unused)
1012 {
1013 
1014 	return (-1);
1015 }
1016 
1017 static void
1018 ttydevsw_defpktnotify(struct tty *tp __unused, char event __unused)
1019 {
1020 
1021 }
1022 
1023 static void
1024 ttydevsw_deffree(void *softc __unused)
1025 {
1026 
1027 	panic("Terminal device freed without a free-handler");
1028 }
1029 
1030 static bool
1031 ttydevsw_defbusy(struct tty *tp __unused)
1032 {
1033 
1034 	return (FALSE);
1035 }
1036 
1037 /*
1038  * TTY allocation and deallocation. TTY devices can be deallocated when
1039  * the driver doesn't use it anymore, when the TTY isn't a session's
1040  * controlling TTY and when the device node isn't opened through devfs.
1041  */
1042 
1043 struct tty *
1044 tty_alloc(struct ttydevsw *tsw, void *sc)
1045 {
1046 
1047 	return (tty_alloc_mutex(tsw, sc, NULL));
1048 }
1049 
1050 struct tty *
1051 tty_alloc_mutex(struct ttydevsw *tsw, void *sc, struct mtx *mutex)
1052 {
1053 	struct tty *tp;
1054 
1055 	/* Make sure the driver defines all routines. */
1056 #define PATCH_FUNC(x) do {				\
1057 	if (tsw->tsw_ ## x == NULL)			\
1058 		tsw->tsw_ ## x = ttydevsw_def ## x;	\
1059 } while (0)
1060 	PATCH_FUNC(open);
1061 	PATCH_FUNC(close);
1062 	PATCH_FUNC(outwakeup);
1063 	PATCH_FUNC(inwakeup);
1064 	PATCH_FUNC(ioctl);
1065 	PATCH_FUNC(cioctl);
1066 	PATCH_FUNC(param);
1067 	PATCH_FUNC(modem);
1068 	PATCH_FUNC(mmap);
1069 	PATCH_FUNC(pktnotify);
1070 	PATCH_FUNC(free);
1071 	PATCH_FUNC(busy);
1072 #undef PATCH_FUNC
1073 
1074 	tp = malloc(sizeof(struct tty) + TTY_PRBUF_SIZE, M_TTY,
1075 	    M_WAITOK | M_ZERO);
1076 	tp->t_prbufsz = TTY_PRBUF_SIZE;
1077 	tp->t_devsw = tsw;
1078 	tp->t_devswsoftc = sc;
1079 	tp->t_flags = tsw->tsw_flags;
1080 	tp->t_drainwait = tty_drainwait;
1081 
1082 	tty_init_termios(tp);
1083 
1084 	cv_init(&tp->t_inwait, "ttyin");
1085 	cv_init(&tp->t_outwait, "ttyout");
1086 	cv_init(&tp->t_outserwait, "ttyosr");
1087 	cv_init(&tp->t_bgwait, "ttybg");
1088 	cv_init(&tp->t_dcdwait, "ttydcd");
1089 
1090 	/* Allow drivers to use a custom mutex to lock the TTY. */
1091 	if (mutex != NULL) {
1092 		tp->t_mtx = mutex;
1093 	} else {
1094 		tp->t_mtx = &tp->t_mtxobj;
1095 		mtx_init(&tp->t_mtxobj, "ttymtx", NULL, MTX_DEF);
1096 	}
1097 
1098 	knlist_init_mtx(&tp->t_inpoll.si_note, tp->t_mtx);
1099 	knlist_init_mtx(&tp->t_outpoll.si_note, tp->t_mtx);
1100 
1101 	return (tp);
1102 }
1103 
1104 static void
1105 tty_dealloc(void *arg)
1106 {
1107 	struct tty *tp = arg;
1108 
1109 	/*
1110 	 * ttyydev_leave() usually frees the i/o queues earlier, but it is
1111 	 * not always called between queue allocation and here.  The queues
1112 	 * may be allocated by ioctls on a pty control device without the
1113 	 * corresponding pty slave device ever being open, or after it is
1114 	 * closed.
1115 	 */
1116 	ttyinq_free(&tp->t_inq);
1117 	ttyoutq_free(&tp->t_outq);
1118 	seldrain(&tp->t_inpoll);
1119 	seldrain(&tp->t_outpoll);
1120 	knlist_destroy(&tp->t_inpoll.si_note);
1121 	knlist_destroy(&tp->t_outpoll.si_note);
1122 
1123 	cv_destroy(&tp->t_inwait);
1124 	cv_destroy(&tp->t_outwait);
1125 	cv_destroy(&tp->t_bgwait);
1126 	cv_destroy(&tp->t_dcdwait);
1127 	cv_destroy(&tp->t_outserwait);
1128 
1129 	if (tp->t_mtx == &tp->t_mtxobj)
1130 		mtx_destroy(&tp->t_mtxobj);
1131 	ttydevsw_free(tp);
1132 	free(tp, M_TTY);
1133 }
1134 
1135 static void
1136 tty_rel_free(struct tty *tp)
1137 {
1138 	struct cdev *dev;
1139 
1140 	tty_assert_locked(tp);
1141 
1142 #define	TF_ACTIVITY	(TF_GONE|TF_OPENED|TF_HOOK|TF_OPENCLOSE)
1143 	if (tp->t_sessioncnt != 0 || (tp->t_flags & TF_ACTIVITY) != TF_GONE) {
1144 		/* TTY is still in use. */
1145 		tty_unlock(tp);
1146 		return;
1147 	}
1148 
1149 	/* Stop asynchronous I/O. */
1150 	funsetown(&tp->t_sigio);
1151 
1152 	/* TTY can be deallocated. */
1153 	dev = tp->t_dev;
1154 	tp->t_dev = NULL;
1155 	tty_unlock(tp);
1156 
1157 	if (dev != NULL) {
1158 		sx_xlock(&tty_list_sx);
1159 		TAILQ_REMOVE(&tty_list, tp, t_list);
1160 		tty_list_count--;
1161 		sx_xunlock(&tty_list_sx);
1162 		destroy_dev_sched_cb(dev, tty_dealloc, tp);
1163 	}
1164 }
1165 
1166 void
1167 tty_rel_pgrp(struct tty *tp, struct pgrp *pg)
1168 {
1169 
1170 	MPASS(tp->t_sessioncnt > 0);
1171 	tty_assert_locked(tp);
1172 
1173 	if (tp->t_pgrp == pg)
1174 		tp->t_pgrp = NULL;
1175 
1176 	tty_unlock(tp);
1177 }
1178 
1179 void
1180 tty_rel_sess(struct tty *tp, struct session *sess)
1181 {
1182 
1183 	MPASS(tp->t_sessioncnt > 0);
1184 
1185 	/* Current session has left. */
1186 	if (tp->t_session == sess) {
1187 		tp->t_session = NULL;
1188 		MPASS(tp->t_pgrp == NULL);
1189 	}
1190 	tp->t_sessioncnt--;
1191 	tty_rel_free(tp);
1192 }
1193 
1194 void
1195 tty_rel_gone(struct tty *tp)
1196 {
1197 
1198 	tty_assert_locked(tp);
1199 	MPASS(!tty_gone(tp));
1200 
1201 	/* Simulate carrier removal. */
1202 	ttydisc_modem(tp, 0);
1203 
1204 	/* Wake up all blocked threads. */
1205 	tty_wakeup(tp, FREAD|FWRITE);
1206 	cv_broadcast(&tp->t_bgwait);
1207 	cv_broadcast(&tp->t_dcdwait);
1208 
1209 	tp->t_flags |= TF_GONE;
1210 	tty_rel_free(tp);
1211 }
1212 
1213 static int
1214 tty_drop_ctty(struct tty *tp, struct proc *p)
1215 {
1216 	struct session *session;
1217 	struct vnode *vp;
1218 
1219 	/*
1220 	 * This looks terrible, but it's generally safe as long as the tty
1221 	 * hasn't gone away while we had the lock dropped.  All of our sanity
1222 	 * checking that this operation is OK happens after we've picked it back
1223 	 * up, so other state changes are generally not fatal and the potential
1224 	 * for this particular operation to happen out-of-order in a
1225 	 * multithreaded scenario is likely a non-issue.
1226 	 */
1227 	tty_unlock(tp);
1228 	sx_xlock(&proctree_lock);
1229 	tty_lock(tp);
1230 	if (tty_gone(tp)) {
1231 		sx_xunlock(&proctree_lock);
1232 		return (ENODEV);
1233 	}
1234 
1235 	/*
1236 	 * If the session doesn't have a controlling TTY, or if we weren't
1237 	 * invoked on the controlling TTY, we'll return ENOIOCTL as we've
1238 	 * historically done.
1239 	 */
1240 	session = p->p_session;
1241 	if (session->s_ttyp == NULL || session->s_ttyp != tp) {
1242 		sx_xunlock(&proctree_lock);
1243 		return (ENOTTY);
1244 	}
1245 
1246 	if (!SESS_LEADER(p)) {
1247 		sx_xunlock(&proctree_lock);
1248 		return (EPERM);
1249 	}
1250 
1251 	PROC_LOCK(p);
1252 	SESS_LOCK(session);
1253 	vp = session->s_ttyvp;
1254 	session->s_ttyp = NULL;
1255 	session->s_ttyvp = NULL;
1256 	session->s_ttydp = NULL;
1257 	SESS_UNLOCK(session);
1258 
1259 	tp->t_sessioncnt--;
1260 	p->p_flag &= ~P_CONTROLT;
1261 	PROC_UNLOCK(p);
1262 	sx_xunlock(&proctree_lock);
1263 
1264 	/*
1265 	 * If we did have a vnode, release our reference.  Ordinarily we manage
1266 	 * these at the devfs layer, but we can't necessarily know that we were
1267 	 * invoked on the vnode referenced in the session (i.e. the vnode we
1268 	 * hold a reference to).  We explicitly don't check VBAD/VIRF_DOOMED here
1269 	 * to avoid a vnode leak -- in circumstances elsewhere where we'd hit a
1270 	 * VIRF_DOOMED vnode, release has been deferred until the controlling TTY
1271 	 * is either changed or released.
1272 	 */
1273 	if (vp != NULL)
1274 		devfs_ctty_unref(vp);
1275 	return (0);
1276 }
1277 
1278 /*
1279  * Exposing information about current TTY's through sysctl
1280  */
1281 
1282 static void
1283 tty_to_xtty(struct tty *tp, struct xtty *xt)
1284 {
1285 
1286 	tty_assert_locked(tp);
1287 
1288 	xt->xt_size = sizeof(struct xtty);
1289 	xt->xt_insize = ttyinq_getsize(&tp->t_inq);
1290 	xt->xt_incc = ttyinq_bytescanonicalized(&tp->t_inq);
1291 	xt->xt_inlc = ttyinq_bytesline(&tp->t_inq);
1292 	xt->xt_inlow = tp->t_inlow;
1293 	xt->xt_outsize = ttyoutq_getsize(&tp->t_outq);
1294 	xt->xt_outcc = ttyoutq_bytesused(&tp->t_outq);
1295 	xt->xt_outlow = tp->t_outlow;
1296 	xt->xt_column = tp->t_column;
1297 	xt->xt_pgid = tp->t_pgrp ? tp->t_pgrp->pg_id : 0;
1298 	xt->xt_sid = tp->t_session ? tp->t_session->s_sid : 0;
1299 	xt->xt_flags = tp->t_flags;
1300 	xt->xt_dev = tp->t_dev ? dev2udev(tp->t_dev) : (uint32_t)NODEV;
1301 }
1302 
1303 static int
1304 sysctl_kern_ttys(SYSCTL_HANDLER_ARGS)
1305 {
1306 	unsigned long lsize;
1307 	struct xtty *xtlist, *xt;
1308 	struct tty *tp;
1309 	int error;
1310 
1311 	sx_slock(&tty_list_sx);
1312 	lsize = tty_list_count * sizeof(struct xtty);
1313 	if (lsize == 0) {
1314 		sx_sunlock(&tty_list_sx);
1315 		return (0);
1316 	}
1317 
1318 	xtlist = xt = malloc(lsize, M_TTY, M_WAITOK);
1319 
1320 	TAILQ_FOREACH(tp, &tty_list, t_list) {
1321 		tty_lock(tp);
1322 		tty_to_xtty(tp, xt);
1323 		tty_unlock(tp);
1324 		xt++;
1325 	}
1326 	sx_sunlock(&tty_list_sx);
1327 
1328 	error = SYSCTL_OUT(req, xtlist, lsize);
1329 	free(xtlist, M_TTY);
1330 	return (error);
1331 }
1332 
1333 SYSCTL_PROC(_kern, OID_AUTO, ttys, CTLTYPE_OPAQUE|CTLFLAG_RD|CTLFLAG_MPSAFE,
1334 	0, 0, sysctl_kern_ttys, "S,xtty", "List of TTYs");
1335 
1336 /*
1337  * Device node creation. Device has been set up, now we can expose it to
1338  * the user.
1339  */
1340 
1341 int
1342 tty_makedevf(struct tty *tp, struct ucred *cred, int flags,
1343     const char *fmt, ...)
1344 {
1345 	va_list ap;
1346 	struct make_dev_args args;
1347 	struct cdev *dev, *init, *lock, *cua, *cinit, *clock;
1348 	const char *prefix = "tty";
1349 	char name[SPECNAMELEN - 3]; /* for "tty" and "cua". */
1350 	uid_t uid;
1351 	gid_t gid;
1352 	mode_t mode;
1353 	int error;
1354 
1355 	/* Remove "tty" prefix from devices like PTY's. */
1356 	if (tp->t_flags & TF_NOPREFIX)
1357 		prefix = "";
1358 
1359 	va_start(ap, fmt);
1360 	vsnrprintf(name, sizeof name, 32, fmt, ap);
1361 	va_end(ap);
1362 
1363 	if (cred == NULL) {
1364 		/* System device. */
1365 		uid = UID_ROOT;
1366 		gid = GID_WHEEL;
1367 		mode = S_IRUSR|S_IWUSR;
1368 	} else {
1369 		/* User device. */
1370 		uid = cred->cr_ruid;
1371 		gid = GID_TTY;
1372 		mode = S_IRUSR|S_IWUSR|S_IWGRP;
1373 	}
1374 
1375 	flags = flags & TTYMK_CLONING ? MAKEDEV_REF : 0;
1376 	flags |= MAKEDEV_CHECKNAME;
1377 
1378 	/* Master call-in device. */
1379 	make_dev_args_init(&args);
1380 	args.mda_flags = flags;
1381 	args.mda_devsw = &ttydev_cdevsw;
1382 	args.mda_cr = cred;
1383 	args.mda_uid = uid;
1384 	args.mda_gid = gid;
1385 	args.mda_mode = mode;
1386 	args.mda_si_drv1 = tp;
1387 	error = make_dev_s(&args, &dev, "%s%s", prefix, name);
1388 	if (error != 0)
1389 		return (error);
1390 	tp->t_dev = dev;
1391 
1392 	init = lock = cua = cinit = clock = NULL;
1393 
1394 	/* Slave call-in devices. */
1395 	if (tp->t_flags & TF_INITLOCK) {
1396 		args.mda_devsw = &ttyil_cdevsw;
1397 		args.mda_unit = TTYUNIT_INIT;
1398 		args.mda_si_drv1 = tp;
1399 		args.mda_si_drv2 = &tp->t_termios_init_in;
1400 		error = make_dev_s(&args, &init, "%s%s.init", prefix, name);
1401 		if (error != 0)
1402 			goto fail;
1403 		dev_depends(dev, init);
1404 
1405 		args.mda_unit = TTYUNIT_LOCK;
1406 		args.mda_si_drv2 = &tp->t_termios_lock_in;
1407 		error = make_dev_s(&args, &lock, "%s%s.lock", prefix, name);
1408 		if (error != 0)
1409 			goto fail;
1410 		dev_depends(dev, lock);
1411 	}
1412 
1413 	/* Call-out devices. */
1414 	if (tp->t_flags & TF_CALLOUT) {
1415 		make_dev_args_init(&args);
1416 		args.mda_flags = flags;
1417 		args.mda_devsw = &ttydev_cdevsw;
1418 		args.mda_cr = cred;
1419 		args.mda_uid = UID_UUCP;
1420 		args.mda_gid = GID_DIALER;
1421 		args.mda_mode = 0660;
1422 		args.mda_unit = TTYUNIT_CALLOUT;
1423 		args.mda_si_drv1 = tp;
1424 		error = make_dev_s(&args, &cua, "cua%s", name);
1425 		if (error != 0)
1426 			goto fail;
1427 		dev_depends(dev, cua);
1428 
1429 		/* Slave call-out devices. */
1430 		if (tp->t_flags & TF_INITLOCK) {
1431 			args.mda_devsw = &ttyil_cdevsw;
1432 			args.mda_unit = TTYUNIT_CALLOUT | TTYUNIT_INIT;
1433 			args.mda_si_drv2 = &tp->t_termios_init_out;
1434 			error = make_dev_s(&args, &cinit, "cua%s.init", name);
1435 			if (error != 0)
1436 				goto fail;
1437 			dev_depends(dev, cinit);
1438 
1439 			args.mda_unit = TTYUNIT_CALLOUT | TTYUNIT_LOCK;
1440 			args.mda_si_drv2 = &tp->t_termios_lock_out;
1441 			error = make_dev_s(&args, &clock, "cua%s.lock", name);
1442 			if (error != 0)
1443 				goto fail;
1444 			dev_depends(dev, clock);
1445 		}
1446 	}
1447 
1448 	sx_xlock(&tty_list_sx);
1449 	TAILQ_INSERT_TAIL(&tty_list, tp, t_list);
1450 	tty_list_count++;
1451 	sx_xunlock(&tty_list_sx);
1452 
1453 	return (0);
1454 
1455 fail:
1456 	destroy_dev(dev);
1457 	if (init)
1458 		destroy_dev(init);
1459 	if (lock)
1460 		destroy_dev(lock);
1461 	if (cinit)
1462 		destroy_dev(cinit);
1463 	if (clock)
1464 		destroy_dev(clock);
1465 
1466 	return (error);
1467 }
1468 
1469 /*
1470  * Signalling processes.
1471  */
1472 
1473 void
1474 tty_signal_sessleader(struct tty *tp, int sig)
1475 {
1476 	struct proc *p;
1477 	struct session *s;
1478 
1479 	tty_assert_locked(tp);
1480 	MPASS(sig >= 1 && sig < NSIG);
1481 
1482 	/* Make signals start output again. */
1483 	tp->t_flags &= ~TF_STOPPED;
1484 	tp->t_termios.c_lflag &= ~FLUSHO;
1485 
1486 	/*
1487 	 * Load s_leader exactly once to avoid race where s_leader is
1488 	 * set to NULL by a concurrent invocation of killjobc() by the
1489 	 * session leader.  Note that we are not holding t_session's
1490 	 * lock for the read.
1491 	 */
1492 	if ((s = tp->t_session) != NULL &&
1493 	    (p = atomic_load_ptr(&s->s_leader)) != NULL) {
1494 		PROC_LOCK(p);
1495 		kern_psignal(p, sig);
1496 		PROC_UNLOCK(p);
1497 	}
1498 }
1499 
1500 void
1501 tty_signal_pgrp(struct tty *tp, int sig)
1502 {
1503 	ksiginfo_t ksi;
1504 
1505 	tty_assert_locked(tp);
1506 	MPASS(sig >= 1 && sig < NSIG);
1507 
1508 	/* Make signals start output again. */
1509 	tp->t_flags &= ~TF_STOPPED;
1510 	tp->t_termios.c_lflag &= ~FLUSHO;
1511 
1512 	if (sig == SIGINFO && !(tp->t_termios.c_lflag & NOKERNINFO))
1513 		tty_info(tp);
1514 	if (tp->t_pgrp != NULL) {
1515 		ksiginfo_init(&ksi);
1516 		ksi.ksi_signo = sig;
1517 		ksi.ksi_code = SI_KERNEL;
1518 		PGRP_LOCK(tp->t_pgrp);
1519 		pgsignal(tp->t_pgrp, sig, 1, &ksi);
1520 		PGRP_UNLOCK(tp->t_pgrp);
1521 	}
1522 }
1523 
1524 void
1525 tty_wakeup(struct tty *tp, int flags)
1526 {
1527 
1528 	if (tp->t_flags & TF_ASYNC && tp->t_sigio != NULL)
1529 		pgsigio(&tp->t_sigio, SIGIO, (tp->t_session != NULL));
1530 
1531 	if (flags & FWRITE) {
1532 		cv_broadcast(&tp->t_outwait);
1533 		selwakeup(&tp->t_outpoll);
1534 		KNOTE_LOCKED(&tp->t_outpoll.si_note, 0);
1535 	}
1536 	if (flags & FREAD) {
1537 		cv_broadcast(&tp->t_inwait);
1538 		selwakeup(&tp->t_inpoll);
1539 		KNOTE_LOCKED(&tp->t_inpoll.si_note, 0);
1540 	}
1541 }
1542 
1543 int
1544 tty_wait(struct tty *tp, struct cv *cv)
1545 {
1546 	int error;
1547 	int revokecnt = tp->t_revokecnt;
1548 
1549 	tty_lock_assert(tp, MA_OWNED|MA_NOTRECURSED);
1550 	MPASS(!tty_gone(tp));
1551 
1552 	error = cv_wait_sig(cv, tp->t_mtx);
1553 
1554 	/* Bail out when the device slipped away. */
1555 	if (tty_gone(tp))
1556 		return (ENXIO);
1557 
1558 	/* Restart the system call when we may have been revoked. */
1559 	if (tp->t_revokecnt != revokecnt)
1560 		return (ERESTART);
1561 
1562 	return (error);
1563 }
1564 
1565 int
1566 tty_timedwait(struct tty *tp, struct cv *cv, int hz)
1567 {
1568 	int error;
1569 	int revokecnt = tp->t_revokecnt;
1570 
1571 	tty_lock_assert(tp, MA_OWNED|MA_NOTRECURSED);
1572 	MPASS(!tty_gone(tp));
1573 
1574 	error = cv_timedwait_sig(cv, tp->t_mtx, hz);
1575 
1576 	/* Bail out when the device slipped away. */
1577 	if (tty_gone(tp))
1578 		return (ENXIO);
1579 
1580 	/* Restart the system call when we may have been revoked. */
1581 	if (tp->t_revokecnt != revokecnt)
1582 		return (ERESTART);
1583 
1584 	return (error);
1585 }
1586 
1587 void
1588 tty_flush(struct tty *tp, int flags)
1589 {
1590 
1591 	if (flags & FWRITE) {
1592 		tp->t_flags &= ~TF_HIWAT_OUT;
1593 		ttyoutq_flush(&tp->t_outq);
1594 		tty_wakeup(tp, FWRITE);
1595 		if (!tty_gone(tp)) {
1596 			ttydevsw_outwakeup(tp);
1597 			ttydevsw_pktnotify(tp, TIOCPKT_FLUSHWRITE);
1598 		}
1599 	}
1600 	if (flags & FREAD) {
1601 		tty_hiwat_in_unblock(tp);
1602 		ttyinq_flush(&tp->t_inq);
1603 		tty_wakeup(tp, FREAD);
1604 		if (!tty_gone(tp)) {
1605 			ttydevsw_inwakeup(tp);
1606 			ttydevsw_pktnotify(tp, TIOCPKT_FLUSHREAD);
1607 		}
1608 	}
1609 }
1610 
1611 void
1612 tty_set_winsize(struct tty *tp, const struct winsize *wsz)
1613 {
1614 
1615 	if (memcmp(&tp->t_winsize, wsz, sizeof(*wsz)) == 0)
1616 		return;
1617 	tp->t_winsize = *wsz;
1618 	tty_signal_pgrp(tp, SIGWINCH);
1619 }
1620 
1621 static int
1622 tty_generic_ioctl(struct tty *tp, u_long cmd, void *data, int fflag,
1623     struct thread *td)
1624 {
1625 	int error;
1626 
1627 	switch (cmd) {
1628 	/*
1629 	 * Modem commands.
1630 	 * The SER_* and TIOCM_* flags are the same, but one bit
1631 	 * shifted. I don't know why.
1632 	 */
1633 	case TIOCSDTR:
1634 		ttydevsw_modem(tp, SER_DTR, 0);
1635 		return (0);
1636 	case TIOCCDTR:
1637 		ttydevsw_modem(tp, 0, SER_DTR);
1638 		return (0);
1639 	case TIOCMSET: {
1640 		int bits = *(int *)data;
1641 		ttydevsw_modem(tp,
1642 		    (bits & (TIOCM_DTR | TIOCM_RTS)) >> 1,
1643 		    ((~bits) & (TIOCM_DTR | TIOCM_RTS)) >> 1);
1644 		return (0);
1645 	}
1646 	case TIOCMBIS: {
1647 		int bits = *(int *)data;
1648 		ttydevsw_modem(tp, (bits & (TIOCM_DTR | TIOCM_RTS)) >> 1, 0);
1649 		return (0);
1650 	}
1651 	case TIOCMBIC: {
1652 		int bits = *(int *)data;
1653 		ttydevsw_modem(tp, 0, (bits & (TIOCM_DTR | TIOCM_RTS)) >> 1);
1654 		return (0);
1655 	}
1656 	case TIOCMGET:
1657 		*(int *)data = TIOCM_LE + (ttydevsw_modem(tp, 0, 0) << 1);
1658 		return (0);
1659 
1660 	case FIOASYNC:
1661 		if (*(int *)data)
1662 			tp->t_flags |= TF_ASYNC;
1663 		else
1664 			tp->t_flags &= ~TF_ASYNC;
1665 		return (0);
1666 	case FIONBIO:
1667 		/* This device supports non-blocking operation. */
1668 		return (0);
1669 	case FIONREAD:
1670 		*(int *)data = ttyinq_bytescanonicalized(&tp->t_inq);
1671 		return (0);
1672 	case FIONWRITE:
1673 	case TIOCOUTQ:
1674 		*(int *)data = ttyoutq_bytesused(&tp->t_outq);
1675 		return (0);
1676 	case FIOSETOWN:
1677 		if (tp->t_session != NULL && !tty_is_ctty(tp, td->td_proc))
1678 			/* Not allowed to set ownership. */
1679 			return (ENOTTY);
1680 
1681 		/* Temporarily unlock the TTY to set ownership. */
1682 		tty_unlock(tp);
1683 		error = fsetown(*(int *)data, &tp->t_sigio);
1684 		tty_lock(tp);
1685 		return (error);
1686 	case FIOGETOWN:
1687 		if (tp->t_session != NULL && !tty_is_ctty(tp, td->td_proc))
1688 			/* Not allowed to set ownership. */
1689 			return (ENOTTY);
1690 
1691 		/* Get ownership. */
1692 		*(int *)data = fgetown(&tp->t_sigio);
1693 		return (0);
1694 	case TIOCGETA:
1695 		/* Obtain terminal flags through tcgetattr(). */
1696 		*(struct termios*)data = tp->t_termios;
1697 		return (0);
1698 	case TIOCSETA:
1699 	case TIOCSETAW:
1700 	case TIOCSETAF: {
1701 		struct termios *t = data;
1702 
1703 		/*
1704 		 * Who makes up these funny rules? According to POSIX,
1705 		 * input baud rate is set equal to the output baud rate
1706 		 * when zero.
1707 		 */
1708 		if (t->c_ispeed == 0)
1709 			t->c_ispeed = t->c_ospeed;
1710 
1711 		/* Discard any unsupported bits. */
1712 		t->c_iflag &= TTYSUP_IFLAG;
1713 		t->c_oflag &= TTYSUP_OFLAG;
1714 		t->c_lflag &= TTYSUP_LFLAG;
1715 		t->c_cflag &= TTYSUP_CFLAG;
1716 
1717 		/* Set terminal flags through tcsetattr(). */
1718 		if (cmd == TIOCSETAW || cmd == TIOCSETAF) {
1719 			error = tty_drain(tp, 0);
1720 			if (error)
1721 				return (error);
1722 			if (cmd == TIOCSETAF)
1723 				tty_flush(tp, FREAD);
1724 		}
1725 
1726 		/*
1727 		 * Only call param() when the flags really change.
1728 		 */
1729 		if ((t->c_cflag & CIGNORE) == 0 &&
1730 		    (tp->t_termios.c_cflag != t->c_cflag ||
1731 		    ((tp->t_termios.c_iflag ^ t->c_iflag) &
1732 		    (IXON|IXOFF|IXANY)) ||
1733 		    tp->t_termios.c_ispeed != t->c_ispeed ||
1734 		    tp->t_termios.c_ospeed != t->c_ospeed)) {
1735 			error = ttydevsw_param(tp, t);
1736 			if (error)
1737 				return (error);
1738 
1739 			/* XXX: CLOCAL? */
1740 
1741 			tp->t_termios.c_cflag = t->c_cflag & ~CIGNORE;
1742 			tp->t_termios.c_ispeed = t->c_ispeed;
1743 			tp->t_termios.c_ospeed = t->c_ospeed;
1744 
1745 			/* Baud rate has changed - update watermarks. */
1746 			error = tty_watermarks(tp);
1747 			if (error)
1748 				return (error);
1749 		}
1750 
1751 		/* Copy new non-device driver parameters. */
1752 		tp->t_termios.c_iflag = t->c_iflag;
1753 		tp->t_termios.c_oflag = t->c_oflag;
1754 		tp->t_termios.c_lflag = t->c_lflag;
1755 		memcpy(&tp->t_termios.c_cc, t->c_cc, sizeof t->c_cc);
1756 
1757 		ttydisc_optimize(tp);
1758 
1759 		if ((t->c_lflag & ICANON) == 0) {
1760 			/*
1761 			 * When in non-canonical mode, wake up all
1762 			 * readers. Canonicalize any partial input. VMIN
1763 			 * and VTIME could also be adjusted.
1764 			 */
1765 			ttyinq_canonicalize(&tp->t_inq);
1766 			tty_wakeup(tp, FREAD);
1767 		}
1768 
1769 		/*
1770 		 * For packet mode: notify the PTY consumer that VSTOP
1771 		 * and VSTART may have been changed.
1772 		 */
1773 		if (tp->t_termios.c_iflag & IXON &&
1774 		    tp->t_termios.c_cc[VSTOP] == CTRL('S') &&
1775 		    tp->t_termios.c_cc[VSTART] == CTRL('Q'))
1776 			ttydevsw_pktnotify(tp, TIOCPKT_DOSTOP);
1777 		else
1778 			ttydevsw_pktnotify(tp, TIOCPKT_NOSTOP);
1779 		return (0);
1780 	}
1781 	case TIOCGETD:
1782 		/* For compatibility - we only support TTYDISC. */
1783 		*(int *)data = TTYDISC;
1784 		return (0);
1785 	case TIOCGPGRP:
1786 		if (!tty_is_ctty(tp, td->td_proc))
1787 			return (ENOTTY);
1788 
1789 		if (tp->t_pgrp != NULL)
1790 			*(int *)data = tp->t_pgrp->pg_id;
1791 		else
1792 			*(int *)data = NO_PID;
1793 		return (0);
1794 	case TIOCGSID:
1795 		if (!tty_is_ctty(tp, td->td_proc))
1796 			return (ENOTTY);
1797 
1798 		MPASS(tp->t_session);
1799 		*(int *)data = tp->t_session->s_sid;
1800 		return (0);
1801 	case TIOCNOTTY:
1802 		return (tty_drop_ctty(tp, td->td_proc));
1803 	case TIOCSCTTY: {
1804 		struct proc *p = td->td_proc;
1805 
1806 		/* XXX: This looks awful. */
1807 		tty_unlock(tp);
1808 		sx_xlock(&proctree_lock);
1809 		tty_lock(tp);
1810 
1811 		if (!SESS_LEADER(p)) {
1812 			/* Only the session leader may do this. */
1813 			sx_xunlock(&proctree_lock);
1814 			return (EPERM);
1815 		}
1816 
1817 		if (tp->t_session != NULL && tp->t_session == p->p_session) {
1818 			/* This is already our controlling TTY. */
1819 			sx_xunlock(&proctree_lock);
1820 			return (0);
1821 		}
1822 
1823 		if (p->p_session->s_ttyp != NULL ||
1824 		    (tp->t_session != NULL && tp->t_session->s_ttyvp != NULL &&
1825 		    tp->t_session->s_ttyvp->v_type != VBAD)) {
1826 			/*
1827 			 * There is already a relation between a TTY and
1828 			 * a session, or the caller is not the session
1829 			 * leader.
1830 			 *
1831 			 * Allow the TTY to be stolen when the vnode is
1832 			 * invalid, but the reference to the TTY is
1833 			 * still active.  This allows immediate reuse of
1834 			 * TTYs of which the session leader has been
1835 			 * killed or the TTY revoked.
1836 			 */
1837 			sx_xunlock(&proctree_lock);
1838 			return (EPERM);
1839 		}
1840 
1841 		/* Connect the session to the TTY. */
1842 		tp->t_session = p->p_session;
1843 		tp->t_session->s_ttyp = tp;
1844 		tp->t_sessioncnt++;
1845 
1846 		/* Assign foreground process group. */
1847 		tp->t_pgrp = p->p_pgrp;
1848 		PROC_LOCK(p);
1849 		p->p_flag |= P_CONTROLT;
1850 		PROC_UNLOCK(p);
1851 
1852 		sx_xunlock(&proctree_lock);
1853 		return (0);
1854 	}
1855 	case TIOCSPGRP: {
1856 		struct pgrp *pg;
1857 
1858 		/*
1859 		 * XXX: Temporarily unlock the TTY to locate the process
1860 		 * group. This code would be lot nicer if we would ever
1861 		 * decompose proctree_lock.
1862 		 */
1863 		tty_unlock(tp);
1864 		sx_slock(&proctree_lock);
1865 		pg = pgfind(*(int *)data);
1866 		if (pg != NULL)
1867 			PGRP_UNLOCK(pg);
1868 		if (pg == NULL || pg->pg_session != td->td_proc->p_session) {
1869 			sx_sunlock(&proctree_lock);
1870 			tty_lock(tp);
1871 			return (EPERM);
1872 		}
1873 		tty_lock(tp);
1874 
1875 		/*
1876 		 * Determine if this TTY is the controlling TTY after
1877 		 * relocking the TTY.
1878 		 */
1879 		if (!tty_is_ctty(tp, td->td_proc)) {
1880 			sx_sunlock(&proctree_lock);
1881 			return (ENOTTY);
1882 		}
1883 		tp->t_pgrp = pg;
1884 		sx_sunlock(&proctree_lock);
1885 
1886 		/* Wake up the background process groups. */
1887 		cv_broadcast(&tp->t_bgwait);
1888 		return (0);
1889 	}
1890 	case TIOCFLUSH: {
1891 		int flags = *(int *)data;
1892 
1893 		if (flags == 0)
1894 			flags = (FREAD|FWRITE);
1895 		else
1896 			flags &= (FREAD|FWRITE);
1897 		tty_flush(tp, flags);
1898 		return (0);
1899 	}
1900 	case TIOCDRAIN:
1901 		/* Drain TTY output. */
1902 		return tty_drain(tp, 0);
1903 	case TIOCGDRAINWAIT:
1904 		*(int *)data = tp->t_drainwait;
1905 		return (0);
1906 	case TIOCSDRAINWAIT:
1907 		error = priv_check(td, PRIV_TTY_DRAINWAIT);
1908 		if (error == 0)
1909 			tp->t_drainwait = *(int *)data;
1910 		return (error);
1911 	case TIOCCONS:
1912 		/* Set terminal as console TTY. */
1913 		if (*(int *)data) {
1914 			error = priv_check(td, PRIV_TTY_CONSOLE);
1915 			if (error)
1916 				return (error);
1917 
1918 			/*
1919 			 * XXX: constty should really need to be locked!
1920 			 * XXX: allow disconnected constty's to be stolen!
1921 			 */
1922 
1923 			if (constty == tp)
1924 				return (0);
1925 			if (constty != NULL)
1926 				return (EBUSY);
1927 
1928 			tty_unlock(tp);
1929 			constty_set(tp);
1930 			tty_lock(tp);
1931 		} else if (constty == tp) {
1932 			constty_clear();
1933 		}
1934 		return (0);
1935 	case TIOCGWINSZ:
1936 		/* Obtain window size. */
1937 		*(struct winsize*)data = tp->t_winsize;
1938 		return (0);
1939 	case TIOCSWINSZ:
1940 		/* Set window size. */
1941 		tty_set_winsize(tp, data);
1942 		return (0);
1943 	case TIOCEXCL:
1944 		tp->t_flags |= TF_EXCLUDE;
1945 		return (0);
1946 	case TIOCNXCL:
1947 		tp->t_flags &= ~TF_EXCLUDE;
1948 		return (0);
1949 	case TIOCSTOP:
1950 		tp->t_flags |= TF_STOPPED;
1951 		ttydevsw_pktnotify(tp, TIOCPKT_STOP);
1952 		return (0);
1953 	case TIOCSTART:
1954 		tp->t_flags &= ~TF_STOPPED;
1955 		tp->t_termios.c_lflag &= ~FLUSHO;
1956 		ttydevsw_outwakeup(tp);
1957 		ttydevsw_pktnotify(tp, TIOCPKT_START);
1958 		return (0);
1959 	case TIOCSTAT:
1960 		tty_info(tp);
1961 		return (0);
1962 	case TIOCSTI:
1963 		if ((fflag & FREAD) == 0 && priv_check(td, PRIV_TTY_STI))
1964 			return (EPERM);
1965 		if (!tty_is_ctty(tp, td->td_proc) &&
1966 		    priv_check(td, PRIV_TTY_STI))
1967 			return (EACCES);
1968 		ttydisc_rint(tp, *(char *)data, 0);
1969 		ttydisc_rint_done(tp);
1970 		return (0);
1971 	}
1972 
1973 #ifdef COMPAT_43TTY
1974 	return tty_ioctl_compat(tp, cmd, data, fflag, td);
1975 #else /* !COMPAT_43TTY */
1976 	return (ENOIOCTL);
1977 #endif /* COMPAT_43TTY */
1978 }
1979 
1980 int
1981 tty_ioctl(struct tty *tp, u_long cmd, void *data, int fflag, struct thread *td)
1982 {
1983 	int error;
1984 
1985 	tty_assert_locked(tp);
1986 
1987 	if (tty_gone(tp))
1988 		return (ENXIO);
1989 
1990 	error = ttydevsw_ioctl(tp, cmd, data, td);
1991 	if (error == ENOIOCTL)
1992 		error = tty_generic_ioctl(tp, cmd, data, fflag, td);
1993 
1994 	return (error);
1995 }
1996 
1997 dev_t
1998 tty_udev(struct tty *tp)
1999 {
2000 
2001 	if (tp->t_dev)
2002 		return (dev2udev(tp->t_dev));
2003 	else
2004 		return (NODEV);
2005 }
2006 
2007 int
2008 tty_checkoutq(struct tty *tp)
2009 {
2010 
2011 	/* 256 bytes should be enough to print a log message. */
2012 	return (ttyoutq_bytesleft(&tp->t_outq) >= 256);
2013 }
2014 
2015 void
2016 tty_hiwat_in_block(struct tty *tp)
2017 {
2018 
2019 	if ((tp->t_flags & TF_HIWAT_IN) == 0 &&
2020 	    tp->t_termios.c_iflag & IXOFF &&
2021 	    tp->t_termios.c_cc[VSTOP] != _POSIX_VDISABLE) {
2022 		/*
2023 		 * Input flow control. Only enter the high watermark when we
2024 		 * can successfully store the VSTOP character.
2025 		 */
2026 		if (ttyoutq_write_nofrag(&tp->t_outq,
2027 		    &tp->t_termios.c_cc[VSTOP], 1) == 0)
2028 			tp->t_flags |= TF_HIWAT_IN;
2029 	} else {
2030 		/* No input flow control. */
2031 		tp->t_flags |= TF_HIWAT_IN;
2032 	}
2033 }
2034 
2035 void
2036 tty_hiwat_in_unblock(struct tty *tp)
2037 {
2038 
2039 	if (tp->t_flags & TF_HIWAT_IN &&
2040 	    tp->t_termios.c_iflag & IXOFF &&
2041 	    tp->t_termios.c_cc[VSTART] != _POSIX_VDISABLE) {
2042 		/*
2043 		 * Input flow control. Only leave the high watermark when we
2044 		 * can successfully store the VSTART character.
2045 		 */
2046 		if (ttyoutq_write_nofrag(&tp->t_outq,
2047 		    &tp->t_termios.c_cc[VSTART], 1) == 0)
2048 			tp->t_flags &= ~TF_HIWAT_IN;
2049 	} else {
2050 		/* No input flow control. */
2051 		tp->t_flags &= ~TF_HIWAT_IN;
2052 	}
2053 
2054 	if (!tty_gone(tp))
2055 		ttydevsw_inwakeup(tp);
2056 }
2057 
2058 /*
2059  * TTY hooks interface.
2060  */
2061 
2062 static int
2063 ttyhook_defrint(struct tty *tp, char c, int flags)
2064 {
2065 
2066 	if (ttyhook_rint_bypass(tp, &c, 1) != 1)
2067 		return (-1);
2068 
2069 	return (0);
2070 }
2071 
2072 int
2073 ttyhook_register(struct tty **rtp, struct proc *p, int fd, struct ttyhook *th,
2074     void *softc)
2075 {
2076 	struct tty *tp;
2077 	struct file *fp;
2078 	struct cdev *dev;
2079 	struct cdevsw *cdp;
2080 	struct filedesc *fdp;
2081 	cap_rights_t rights;
2082 	int error, ref;
2083 
2084 	/* Validate the file descriptor. */
2085 	fdp = p->p_fd;
2086 	error = fget_unlocked(fdp, fd, cap_rights_init(&rights, CAP_TTYHOOK),
2087 	    &fp);
2088 	if (error != 0)
2089 		return (error);
2090 	if (fp->f_ops == &badfileops) {
2091 		error = EBADF;
2092 		goto done1;
2093 	}
2094 
2095 	/*
2096 	 * Make sure the vnode is bound to a character device.
2097 	 * Unlocked check for the vnode type is ok there, because we
2098 	 * only shall prevent calling devvn_refthread on the file that
2099 	 * never has been opened over a character device.
2100 	 */
2101 	if (fp->f_type != DTYPE_VNODE || fp->f_vnode->v_type != VCHR) {
2102 		error = EINVAL;
2103 		goto done1;
2104 	}
2105 
2106 	/* Make sure it is a TTY. */
2107 	cdp = devvn_refthread(fp->f_vnode, &dev, &ref);
2108 	if (cdp == NULL) {
2109 		error = ENXIO;
2110 		goto done1;
2111 	}
2112 	if (dev != fp->f_data) {
2113 		error = ENXIO;
2114 		goto done2;
2115 	}
2116 	if (cdp != &ttydev_cdevsw) {
2117 		error = ENOTTY;
2118 		goto done2;
2119 	}
2120 	tp = dev->si_drv1;
2121 
2122 	/* Try to attach the hook to the TTY. */
2123 	error = EBUSY;
2124 	tty_lock(tp);
2125 	MPASS((tp->t_hook == NULL) == ((tp->t_flags & TF_HOOK) == 0));
2126 	if (tp->t_flags & TF_HOOK)
2127 		goto done3;
2128 
2129 	tp->t_flags |= TF_HOOK;
2130 	tp->t_hook = th;
2131 	tp->t_hooksoftc = softc;
2132 	*rtp = tp;
2133 	error = 0;
2134 
2135 	/* Maybe we can switch into bypass mode now. */
2136 	ttydisc_optimize(tp);
2137 
2138 	/* Silently convert rint() calls to rint_bypass() when possible. */
2139 	if (!ttyhook_hashook(tp, rint) && ttyhook_hashook(tp, rint_bypass))
2140 		th->th_rint = ttyhook_defrint;
2141 
2142 done3:	tty_unlock(tp);
2143 done2:	dev_relthread(dev, ref);
2144 done1:	fdrop(fp, curthread);
2145 	return (error);
2146 }
2147 
2148 void
2149 ttyhook_unregister(struct tty *tp)
2150 {
2151 
2152 	tty_assert_locked(tp);
2153 	MPASS(tp->t_flags & TF_HOOK);
2154 
2155 	/* Disconnect the hook. */
2156 	tp->t_flags &= ~TF_HOOK;
2157 	tp->t_hook = NULL;
2158 
2159 	/* Maybe we need to leave bypass mode. */
2160 	ttydisc_optimize(tp);
2161 
2162 	/* Maybe deallocate the TTY as well. */
2163 	tty_rel_free(tp);
2164 }
2165 
2166 /*
2167  * /dev/console handling.
2168  */
2169 
2170 static int
2171 ttyconsdev_open(struct cdev *dev, int oflags, int devtype, struct thread *td)
2172 {
2173 	struct tty *tp;
2174 
2175 	/* System has no console device. */
2176 	if (dev_console_filename == NULL)
2177 		return (ENXIO);
2178 
2179 	/* Look up corresponding TTY by device name. */
2180 	sx_slock(&tty_list_sx);
2181 	TAILQ_FOREACH(tp, &tty_list, t_list) {
2182 		if (strcmp(dev_console_filename, tty_devname(tp)) == 0) {
2183 			dev_console->si_drv1 = tp;
2184 			break;
2185 		}
2186 	}
2187 	sx_sunlock(&tty_list_sx);
2188 
2189 	/* System console has no TTY associated. */
2190 	if (dev_console->si_drv1 == NULL)
2191 		return (ENXIO);
2192 
2193 	return (ttydev_open(dev, oflags, devtype, td));
2194 }
2195 
2196 static int
2197 ttyconsdev_write(struct cdev *dev, struct uio *uio, int ioflag)
2198 {
2199 
2200 	log_console(uio);
2201 
2202 	return (ttydev_write(dev, uio, ioflag));
2203 }
2204 
2205 /*
2206  * /dev/console is a little different than normal TTY's.  When opened,
2207  * it determines which TTY to use.  When data gets written to it, it
2208  * will be logged in the kernel message buffer.
2209  */
2210 static struct cdevsw ttyconsdev_cdevsw = {
2211 	.d_version	= D_VERSION,
2212 	.d_open		= ttyconsdev_open,
2213 	.d_close	= ttydev_close,
2214 	.d_read		= ttydev_read,
2215 	.d_write	= ttyconsdev_write,
2216 	.d_ioctl	= ttydev_ioctl,
2217 	.d_kqfilter	= ttydev_kqfilter,
2218 	.d_poll		= ttydev_poll,
2219 	.d_mmap		= ttydev_mmap,
2220 	.d_name		= "ttyconsdev",
2221 	.d_flags	= D_TTY,
2222 };
2223 
2224 static void
2225 ttyconsdev_init(void *unused __unused)
2226 {
2227 
2228 	dev_console = make_dev_credf(MAKEDEV_ETERNAL, &ttyconsdev_cdevsw, 0,
2229 	    NULL, UID_ROOT, GID_WHEEL, 0600, "console");
2230 }
2231 
2232 SYSINIT(tty, SI_SUB_DRIVERS, SI_ORDER_FIRST, ttyconsdev_init, NULL);
2233 
2234 void
2235 ttyconsdev_select(const char *name)
2236 {
2237 
2238 	dev_console_filename = name;
2239 }
2240 
2241 /*
2242  * Debugging routines.
2243  */
2244 
2245 #include "opt_ddb.h"
2246 #ifdef DDB
2247 #include <ddb/ddb.h>
2248 #include <ddb/db_sym.h>
2249 
2250 static const struct {
2251 	int flag;
2252 	char val;
2253 } ttystates[] = {
2254 #if 0
2255 	{ TF_NOPREFIX,		'N' },
2256 #endif
2257 	{ TF_INITLOCK,		'I' },
2258 	{ TF_CALLOUT,		'C' },
2259 
2260 	/* Keep these together -> 'Oi' and 'Oo'. */
2261 	{ TF_OPENED,		'O' },
2262 	{ TF_OPENED_IN,		'i' },
2263 	{ TF_OPENED_OUT,	'o' },
2264 	{ TF_OPENED_CONS,	'c' },
2265 
2266 	{ TF_GONE,		'G' },
2267 	{ TF_OPENCLOSE,		'B' },
2268 	{ TF_ASYNC,		'Y' },
2269 	{ TF_LITERAL,		'L' },
2270 
2271 	/* Keep these together -> 'Hi' and 'Ho'. */
2272 	{ TF_HIWAT,		'H' },
2273 	{ TF_HIWAT_IN,		'i' },
2274 	{ TF_HIWAT_OUT,		'o' },
2275 
2276 	{ TF_STOPPED,		'S' },
2277 	{ TF_EXCLUDE,		'X' },
2278 	{ TF_BYPASS,		'l' },
2279 	{ TF_ZOMBIE,		'Z' },
2280 	{ TF_HOOK,		's' },
2281 
2282 	/* Keep these together -> 'bi' and 'bo'. */
2283 	{ TF_BUSY,		'b' },
2284 	{ TF_BUSY_IN,		'i' },
2285 	{ TF_BUSY_OUT,		'o' },
2286 
2287 	{ 0,			'\0'},
2288 };
2289 
2290 #define	TTY_FLAG_BITS \
2291 	"\20\1NOPREFIX\2INITLOCK\3CALLOUT\4OPENED_IN" \
2292 	"\5OPENED_OUT\6OPENED_CONS\7GONE\10OPENCLOSE" \
2293 	"\11ASYNC\12LITERAL\13HIWAT_IN\14HIWAT_OUT" \
2294 	"\15STOPPED\16EXCLUDE\17BYPASS\20ZOMBIE" \
2295 	"\21HOOK\22BUSY_IN\23BUSY_OUT"
2296 
2297 #define DB_PRINTSYM(name, addr) \
2298 	db_printf("%s  " #name ": ", sep); \
2299 	db_printsym((db_addr_t) addr, DB_STGY_ANY); \
2300 	db_printf("\n");
2301 
2302 static void
2303 _db_show_devsw(const char *sep, const struct ttydevsw *tsw)
2304 {
2305 
2306 	db_printf("%sdevsw: ", sep);
2307 	db_printsym((db_addr_t)tsw, DB_STGY_ANY);
2308 	db_printf(" (%p)\n", tsw);
2309 	DB_PRINTSYM(open, tsw->tsw_open);
2310 	DB_PRINTSYM(close, tsw->tsw_close);
2311 	DB_PRINTSYM(outwakeup, tsw->tsw_outwakeup);
2312 	DB_PRINTSYM(inwakeup, tsw->tsw_inwakeup);
2313 	DB_PRINTSYM(ioctl, tsw->tsw_ioctl);
2314 	DB_PRINTSYM(param, tsw->tsw_param);
2315 	DB_PRINTSYM(modem, tsw->tsw_modem);
2316 	DB_PRINTSYM(mmap, tsw->tsw_mmap);
2317 	DB_PRINTSYM(pktnotify, tsw->tsw_pktnotify);
2318 	DB_PRINTSYM(free, tsw->tsw_free);
2319 }
2320 
2321 static void
2322 _db_show_hooks(const char *sep, const struct ttyhook *th)
2323 {
2324 
2325 	db_printf("%shook: ", sep);
2326 	db_printsym((db_addr_t)th, DB_STGY_ANY);
2327 	db_printf(" (%p)\n", th);
2328 	if (th == NULL)
2329 		return;
2330 	DB_PRINTSYM(rint, th->th_rint);
2331 	DB_PRINTSYM(rint_bypass, th->th_rint_bypass);
2332 	DB_PRINTSYM(rint_done, th->th_rint_done);
2333 	DB_PRINTSYM(rint_poll, th->th_rint_poll);
2334 	DB_PRINTSYM(getc_inject, th->th_getc_inject);
2335 	DB_PRINTSYM(getc_capture, th->th_getc_capture);
2336 	DB_PRINTSYM(getc_poll, th->th_getc_poll);
2337 	DB_PRINTSYM(close, th->th_close);
2338 }
2339 
2340 static void
2341 _db_show_termios(const char *name, const struct termios *t)
2342 {
2343 
2344 	db_printf("%s: iflag 0x%x oflag 0x%x cflag 0x%x "
2345 	    "lflag 0x%x ispeed %u ospeed %u\n", name,
2346 	    t->c_iflag, t->c_oflag, t->c_cflag, t->c_lflag,
2347 	    t->c_ispeed, t->c_ospeed);
2348 }
2349 
2350 /* DDB command to show TTY statistics. */
2351 DB_SHOW_COMMAND(tty, db_show_tty)
2352 {
2353 	struct tty *tp;
2354 
2355 	if (!have_addr) {
2356 		db_printf("usage: show tty <addr>\n");
2357 		return;
2358 	}
2359 	tp = (struct tty *)addr;
2360 
2361 	db_printf("%p: %s\n", tp, tty_devname(tp));
2362 	db_printf("\tmtx: %p\n", tp->t_mtx);
2363 	db_printf("\tflags: 0x%b\n", tp->t_flags, TTY_FLAG_BITS);
2364 	db_printf("\trevokecnt: %u\n", tp->t_revokecnt);
2365 
2366 	/* Buffering mechanisms. */
2367 	db_printf("\tinq: %p begin %u linestart %u reprint %u end %u "
2368 	    "nblocks %u quota %u\n", &tp->t_inq, tp->t_inq.ti_begin,
2369 	    tp->t_inq.ti_linestart, tp->t_inq.ti_reprint, tp->t_inq.ti_end,
2370 	    tp->t_inq.ti_nblocks, tp->t_inq.ti_quota);
2371 	db_printf("\toutq: %p begin %u end %u nblocks %u quota %u\n",
2372 	    &tp->t_outq, tp->t_outq.to_begin, tp->t_outq.to_end,
2373 	    tp->t_outq.to_nblocks, tp->t_outq.to_quota);
2374 	db_printf("\tinlow: %zu\n", tp->t_inlow);
2375 	db_printf("\toutlow: %zu\n", tp->t_outlow);
2376 	_db_show_termios("\ttermios", &tp->t_termios);
2377 	db_printf("\twinsize: row %u col %u xpixel %u ypixel %u\n",
2378 	    tp->t_winsize.ws_row, tp->t_winsize.ws_col,
2379 	    tp->t_winsize.ws_xpixel, tp->t_winsize.ws_ypixel);
2380 	db_printf("\tcolumn: %u\n", tp->t_column);
2381 	db_printf("\twritepos: %u\n", tp->t_writepos);
2382 	db_printf("\tcompatflags: 0x%x\n", tp->t_compatflags);
2383 
2384 	/* Init/lock-state devices. */
2385 	_db_show_termios("\ttermios_init_in", &tp->t_termios_init_in);
2386 	_db_show_termios("\ttermios_init_out", &tp->t_termios_init_out);
2387 	_db_show_termios("\ttermios_lock_in", &tp->t_termios_lock_in);
2388 	_db_show_termios("\ttermios_lock_out", &tp->t_termios_lock_out);
2389 
2390 	/* Hooks */
2391 	_db_show_devsw("\t", tp->t_devsw);
2392 	_db_show_hooks("\t", tp->t_hook);
2393 
2394 	/* Process info. */
2395 	db_printf("\tpgrp: %p gid %d jobc %d\n", tp->t_pgrp,
2396 	    tp->t_pgrp ? tp->t_pgrp->pg_id : 0,
2397 	    tp->t_pgrp ? tp->t_pgrp->pg_jobc : 0);
2398 	db_printf("\tsession: %p", tp->t_session);
2399 	if (tp->t_session != NULL)
2400 	    db_printf(" count %u leader %p tty %p sid %d login %s",
2401 		tp->t_session->s_count, tp->t_session->s_leader,
2402 		tp->t_session->s_ttyp, tp->t_session->s_sid,
2403 		tp->t_session->s_login);
2404 	db_printf("\n");
2405 	db_printf("\tsessioncnt: %u\n", tp->t_sessioncnt);
2406 	db_printf("\tdevswsoftc: %p\n", tp->t_devswsoftc);
2407 	db_printf("\thooksoftc: %p\n", tp->t_hooksoftc);
2408 	db_printf("\tdev: %p\n", tp->t_dev);
2409 }
2410 
2411 /* DDB command to list TTYs. */
2412 DB_SHOW_ALL_COMMAND(ttys, db_show_all_ttys)
2413 {
2414 	struct tty *tp;
2415 	size_t isiz, osiz;
2416 	int i, j;
2417 
2418 	/* Make the output look like `pstat -t'. */
2419 	db_printf("PTR        ");
2420 #if defined(__LP64__)
2421 	db_printf("        ");
2422 #endif
2423 	db_printf("      LINE   INQ  CAN  LIN  LOW  OUTQ  USE  LOW   "
2424 	    "COL  SESS  PGID STATE\n");
2425 
2426 	TAILQ_FOREACH(tp, &tty_list, t_list) {
2427 		isiz = tp->t_inq.ti_nblocks * TTYINQ_DATASIZE;
2428 		osiz = tp->t_outq.to_nblocks * TTYOUTQ_DATASIZE;
2429 
2430 		db_printf("%p %10s %5zu %4u %4u %4zu %5zu %4u %4zu %5u %5d "
2431 		    "%5d ", tp, tty_devname(tp), isiz,
2432 		    tp->t_inq.ti_linestart - tp->t_inq.ti_begin,
2433 		    tp->t_inq.ti_end - tp->t_inq.ti_linestart,
2434 		    isiz - tp->t_inlow, osiz,
2435 		    tp->t_outq.to_end - tp->t_outq.to_begin,
2436 		    osiz - tp->t_outlow, MIN(tp->t_column, 99999),
2437 		    tp->t_session ? tp->t_session->s_sid : 0,
2438 		    tp->t_pgrp ? tp->t_pgrp->pg_id : 0);
2439 
2440 		/* Flag bits. */
2441 		for (i = j = 0; ttystates[i].flag; i++)
2442 			if (tp->t_flags & ttystates[i].flag) {
2443 				db_printf("%c", ttystates[i].val);
2444 				j++;
2445 			}
2446 		if (j == 0)
2447 			db_printf("-");
2448 		db_printf("\n");
2449 	}
2450 }
2451 #endif /* DDB */
2452