xref: /freebsd/sys/kern/tty.c (revision 36138969847b231cd98f48272e2bdf88a8dc08dd)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
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 #include "opt_capsicum.h"
34 #include "opt_printf.h"
35 
36 #include <sys/param.h>
37 #include <sys/capsicum.h>
38 #include <sys/conf.h>
39 #include <sys/cons.h>
40 #include <sys/fcntl.h>
41 #include <sys/file.h>
42 #include <sys/filedesc.h>
43 #include <sys/filio.h>
44 #ifdef COMPAT_43TTY
45 #include <sys/ioctl_compat.h>
46 #endif /* COMPAT_43TTY */
47 #include <sys/jail.h>
48 #include <sys/kernel.h>
49 #include <sys/limits.h>
50 #include <sys/malloc.h>
51 #include <sys/mount.h>
52 #include <sys/poll.h>
53 #include <sys/priv.h>
54 #include <sys/proc.h>
55 #include <sys/serial.h>
56 #include <sys/signal.h>
57 #include <sys/stat.h>
58 #include <sys/stdarg.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 static MALLOC_DEFINE(M_TTY, "tty", "tty device");
73 
74 static void tty_rel_free(struct tty *tp);
75 
76 static TAILQ_HEAD(, tty) tty_list = TAILQ_HEAD_INITIALIZER(tty_list);
77 static struct sx tty_list_sx;
78 SX_SYSINIT(tty_list, &tty_list_sx, "tty list");
79 static unsigned int tty_list_count = 0;
80 
81 /* Character device of /dev/console. */
82 static struct cdev	*dev_console;
83 static const char	*dev_console_filename;
84 
85 /*
86  * Flags that are supported and stored by this implementation.
87  */
88 #define TTYSUP_IFLAG	(IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK|ISTRIP|INLCR|\
89 			IGNCR|ICRNL|IXON|IXOFF|IXANY|IMAXBEL|IUTF8)
90 #define TTYSUP_OFLAG	(OPOST|ONLCR|TAB3|ONOEOT|OCRNL|ONOCR|ONLRET)
91 #define TTYSUP_LFLAG	(ECHOKE|ECHOE|ECHOK|ECHO|ECHONL|ECHOPRT|\
92 			ECHOCTL|ISIG|ICANON|ALTWERASE|IEXTEN|TOSTOP|\
93 			FLUSHO|NOKERNINFO|NOFLSH)
94 #define TTYSUP_CFLAG	(CIGNORE|CSIZE|CSTOPB|CREAD|PARENB|PARODD|\
95 			HUPCL|CLOCAL|CCTS_OFLOW|CRTS_IFLOW|CDTR_IFLOW|\
96 			CDSR_OFLOW|CCAR_OFLOW|CNO_RTSDTR)
97 
98 #define	TTY_CALLOUT(tp,d) (dev2unit(d) & TTYUNIT_CALLOUT)
99 
100 static int  tty_drainwait = 5 * 60;
101 SYSCTL_INT(_kern, OID_AUTO, tty_drainwait, CTLFLAG_RWTUN,
102     &tty_drainwait, 0, "Default output drain timeout in seconds");
103 
104 /*
105  * Set TTY buffer sizes.
106  */
107 
108 #define	TTYBUF_MAX	65536
109 
110 #ifdef PRINTF_BUFR_SIZE
111 #define	TTY_PRBUF_SIZE	PRINTF_BUFR_SIZE
112 #else
113 #define	TTY_PRBUF_SIZE	256
114 #endif
115 
116 /*
117  * Allocate buffer space if necessary, and set low watermarks, based on speed.
118  * Note that the ttyxxxq_setsize() functions may drop and then reacquire the tty
119  * lock during memory allocation.  They will return ENXIO if the tty disappears
120  * while unlocked.
121  */
122 static int
tty_watermarks(struct tty * tp)123 tty_watermarks(struct tty *tp)
124 {
125 	size_t bs = 0;
126 	int error;
127 
128 	/* Provide an input buffer for 2 seconds of data. */
129 	if (tp->t_termios.c_cflag & CREAD)
130 		bs = MIN(tp->t_termios.c_ispeed / 5, TTYBUF_MAX);
131 	error = ttyinq_setsize(&tp->t_inq, tp, bs);
132 	if (error != 0)
133 		return (error);
134 
135 	/* Set low watermark at 10% (when 90% is available). */
136 	tp->t_inlow = (ttyinq_getallocatedsize(&tp->t_inq) * 9) / 10;
137 
138 	/* Provide an output buffer for 2 seconds of data. */
139 	bs = MIN(tp->t_termios.c_ospeed / 5, TTYBUF_MAX);
140 	error = ttyoutq_setsize(&tp->t_outq, tp, bs);
141 	if (error != 0)
142 		return (error);
143 
144 	/* Set low watermark at 10% (when 90% is available). */
145 	tp->t_outlow = (ttyoutq_getallocatedsize(&tp->t_outq) * 9) / 10;
146 
147 	return (0);
148 }
149 
150 static int
tty_drain(struct tty * tp,int leaving)151 tty_drain(struct tty *tp, int leaving)
152 {
153 	sbintime_t timeout_at;
154 	size_t bytes;
155 	int error;
156 
157 	if (ttyhook_hashook(tp, getc_inject))
158 		/* buffer is inaccessible */
159 		return (0);
160 
161 	/*
162 	 * For close(), use the recent historic timeout of "1 second without
163 	 * making progress".  For tcdrain(), use t_drainwait as the timeout,
164 	 * with zero meaning "no timeout" which gives POSIX behavior.
165 	 */
166 	if (leaving)
167 		timeout_at = getsbinuptime() + SBT_1S;
168 	else if (tp->t_drainwait != 0)
169 		timeout_at = getsbinuptime() + SBT_1S * tp->t_drainwait;
170 	else
171 		timeout_at = 0;
172 
173 	/*
174 	 * Poll the output buffer and the hardware for completion, at 10 Hz.
175 	 * Polling is required for devices which are not able to signal an
176 	 * interrupt when the transmitter becomes idle (most USB serial devs).
177 	 * The unusual structure of this loop ensures we check for busy one more
178 	 * time after tty_timedwait() returns EWOULDBLOCK, so that success has
179 	 * higher priority than timeout if the IO completed in the last 100mS.
180 	 */
181 	error = 0;
182 	bytes = ttyoutq_bytesused(&tp->t_outq);
183 	for (;;) {
184 		if (ttyoutq_bytesused(&tp->t_outq) == 0 && !ttydevsw_busy(tp))
185 			return (0);
186 		if (error != 0)
187 			return (error);
188 		ttydevsw_outwakeup(tp);
189 		error = tty_timedwait(tp, &tp->t_outwait, hz / 10);
190 		if (error != 0 && error != EWOULDBLOCK)
191 			return (error);
192 		else if (timeout_at == 0 || getsbinuptime() < timeout_at)
193 			error = 0;
194 		else if (leaving && ttyoutq_bytesused(&tp->t_outq) < bytes) {
195 			/* In close, making progress, grant an extra second. */
196 			error = 0;
197 			timeout_at += SBT_1S;
198 			bytes = ttyoutq_bytesused(&tp->t_outq);
199 		}
200 	}
201 }
202 
203 /*
204  * Though ttydev_enter() and ttydev_leave() seem to be related, they
205  * don't have to be used together. ttydev_enter() is used by the cdev
206  * operations to prevent an actual operation from being processed when
207  * the TTY has been abandoned. ttydev_leave() is used by ttydev_open()
208  * and ttydev_close() to determine whether per-TTY data should be
209  * deallocated.
210  */
211 
212 static __inline int
ttydev_enter(struct tty * tp)213 ttydev_enter(struct tty *tp)
214 {
215 
216 	tty_lock(tp);
217 
218 	if (tty_gone(tp) || !tty_opened(tp)) {
219 		/* Device is already gone. */
220 		tty_unlock(tp);
221 		return (ENXIO);
222 	}
223 
224 	return (0);
225 }
226 
227 static void
ttydev_leave(struct tty * tp)228 ttydev_leave(struct tty *tp)
229 {
230 
231 	tty_assert_locked(tp);
232 
233 	if (tty_opened(tp) || tp->t_flags & TF_OPENCLOSE) {
234 		/* Device is still opened somewhere. */
235 		tty_unlock(tp);
236 		return;
237 	}
238 
239 	tp->t_flags |= TF_OPENCLOSE;
240 
241 	/* Remove console TTY. */
242 	constty_clear(tp);
243 
244 	/* Drain any output. */
245 	if (!tty_gone(tp))
246 		tty_drain(tp, 1);
247 
248 	ttydisc_close(tp);
249 
250 	/* Free i/o queues now since they might be large. */
251 	ttyinq_free(&tp->t_inq);
252 	tp->t_inlow = 0;
253 	ttyoutq_free(&tp->t_outq);
254 	tp->t_outlow = 0;
255 
256 	if (!tty_gone(tp))
257 		ttydevsw_close(tp);
258 
259 	tp->t_flags &= ~TF_OPENCLOSE;
260 	cv_broadcast(&tp->t_dcdwait);
261 	tty_rel_free(tp);
262 }
263 
264 /*
265  * Operations that are exposed through the character device in /dev.
266  */
267 static int
ttydev_open(struct cdev * dev,int oflags,int devtype __unused,struct thread * td)268 ttydev_open(struct cdev *dev, int oflags, int devtype __unused,
269     struct thread *td)
270 {
271 	struct tty *tp;
272 	int error;
273 
274 	tp = dev->si_drv1;
275 	error = 0;
276 	tty_lock(tp);
277 	if (tty_gone(tp)) {
278 		/* Device is already gone. */
279 		tty_unlock(tp);
280 		return (ENXIO);
281 	}
282 
283 	/*
284 	 * Block when other processes are currently opening or closing
285 	 * the TTY.
286 	 */
287 	while (tp->t_flags & TF_OPENCLOSE) {
288 		error = tty_wait(tp, &tp->t_dcdwait);
289 		if (error != 0) {
290 			tty_unlock(tp);
291 			return (error);
292 		}
293 	}
294 	tp->t_flags |= TF_OPENCLOSE;
295 
296 	/*
297 	 * Make sure the "tty" and "cua" device cannot be opened at the
298 	 * same time.  The console is a "tty" device.
299 	 */
300 	if (TTY_CALLOUT(tp, dev)) {
301 		if (tp->t_flags & (TF_OPENED_CONS | TF_OPENED_IN)) {
302 			error = EBUSY;
303 			goto done;
304 		}
305 	} else {
306 		if (tp->t_flags & TF_OPENED_OUT) {
307 			error = EBUSY;
308 			goto done;
309 		}
310 	}
311 
312 	if (tp->t_flags & TF_EXCLUDE && priv_check(td, PRIV_TTY_EXCLUSIVE)) {
313 		error = EBUSY;
314 		goto done;
315 	}
316 
317 	if (!tty_opened(tp)) {
318 		/* Set proper termios flags. */
319 		if (TTY_CALLOUT(tp, dev))
320 			tp->t_termios = tp->t_termios_init_out;
321 		else
322 			tp->t_termios = tp->t_termios_init_in;
323 		ttydevsw_param(tp, &tp->t_termios);
324 		/* Prevent modem control on callout devices and /dev/console. */
325 		if (TTY_CALLOUT(tp, dev) || dev == dev_console)
326 			tp->t_termios.c_cflag |= CLOCAL;
327 
328 		if ((tp->t_termios.c_cflag & CNO_RTSDTR) == 0)
329 			ttydevsw_modem(tp, SER_DTR|SER_RTS, 0);
330 
331 		error = ttydevsw_open(tp);
332 		if (error != 0)
333 			goto done;
334 
335 		ttydisc_open(tp);
336 		error = tty_watermarks(tp);
337 		if (error != 0)
338 			goto done;
339 	}
340 
341 	/* Wait for Carrier Detect. */
342 	if ((oflags & O_NONBLOCK) == 0 &&
343 	    (tp->t_termios.c_cflag & CLOCAL) == 0) {
344 		while ((ttydevsw_modem(tp, 0, 0) & SER_DCD) == 0) {
345 			error = tty_wait(tp, &tp->t_dcdwait);
346 			if (error != 0)
347 				goto done;
348 		}
349 	}
350 
351 	if (dev == dev_console)
352 		tp->t_flags |= TF_OPENED_CONS;
353 	else if (TTY_CALLOUT(tp, dev))
354 		tp->t_flags |= TF_OPENED_OUT;
355 	else
356 		tp->t_flags |= TF_OPENED_IN;
357 	MPASS((tp->t_flags & (TF_OPENED_CONS | TF_OPENED_IN)) == 0 ||
358 	    (tp->t_flags & TF_OPENED_OUT) == 0);
359 
360 done:	tp->t_flags &= ~TF_OPENCLOSE;
361 	cv_broadcast(&tp->t_dcdwait);
362 	ttydev_leave(tp);
363 
364 	return (error);
365 }
366 
367 static int
ttydev_close(struct cdev * dev,int fflag,int devtype __unused,struct thread * td)368 ttydev_close(struct cdev *dev, int fflag, int devtype __unused,
369     struct thread *td)
370 {
371 	struct tty *tp = dev->si_drv1;
372 
373 	tty_lock(tp);
374 
375 	/*
376 	 * Don't actually close the device if it is being used as the
377 	 * console.
378 	 */
379 	MPASS((tp->t_flags & (TF_OPENED_CONS | TF_OPENED_IN)) == 0 ||
380 	    (tp->t_flags & TF_OPENED_OUT) == 0);
381 	if (dev == dev_console)
382 		tp->t_flags &= ~TF_OPENED_CONS;
383 	else
384 		tp->t_flags &= ~(TF_OPENED_IN|TF_OPENED_OUT);
385 
386 	if (tp->t_flags & TF_OPENED) {
387 		tty_unlock(tp);
388 		return (0);
389 	}
390 
391 	/* If revoking, flush output now to avoid draining it later. */
392 	if ((fflag & FREVOKE) != 0) {
393 		tty_flush(tp, FWRITE);
394 		knlist_delete(&tp->t_inpoll.si_note, td, 1);
395 		knlist_delete(&tp->t_outpoll.si_note, td, 1);
396 	}
397 
398 	tp->t_flags &= ~TF_EXCLUDE;
399 
400 	/* Properly wake up threads that are stuck - revoke(). */
401 	tp->t_revokecnt++;
402 	tty_wakeup(tp, FREAD|FWRITE);
403 	cv_broadcast(&tp->t_bgwait);
404 	cv_broadcast(&tp->t_dcdwait);
405 
406 	ttydev_leave(tp);
407 
408 	return (0);
409 }
410 
411 static __inline int
tty_is_ctty(struct tty * tp,struct proc * p)412 tty_is_ctty(struct tty *tp, struct proc *p)
413 {
414 
415 	tty_assert_locked(tp);
416 
417 	return (p->p_session == tp->t_session && p->p_flag & P_CONTROLT);
418 }
419 
420 int
tty_wait_background(struct tty * tp,struct thread * td,int sig)421 tty_wait_background(struct tty *tp, struct thread *td, int sig)
422 {
423 	struct proc *p;
424 	struct pgrp *pg;
425 	ksiginfo_t ksi;
426 	int error;
427 
428 	MPASS(sig == SIGTTIN || sig == SIGTTOU);
429 	tty_assert_locked(tp);
430 
431 	p = td->td_proc;
432 	for (;;) {
433 		pg = p->p_pgrp;
434 		PGRP_LOCK(pg);
435 		PROC_LOCK(p);
436 
437 		/*
438 		 * pg may no longer be our process group.
439 		 * Re-check after locking.
440 		 */
441 		if (p->p_pgrp != pg) {
442 			PROC_UNLOCK(p);
443 			PGRP_UNLOCK(pg);
444 			continue;
445 		}
446 
447 		/*
448 		 * The process should only sleep, when:
449 		 * - This terminal is the controlling terminal
450 		 * - Its process group is not the foreground process
451 		 *   group
452 		 * - The parent process isn't waiting for the child to
453 		 *   exit
454 		 * - the signal to send to the process isn't masked
455 		 */
456 		if (!tty_is_ctty(tp, p) || p->p_pgrp == tp->t_pgrp) {
457 			/* Allow the action to happen. */
458 			PROC_UNLOCK(p);
459 			PGRP_UNLOCK(pg);
460 			return (0);
461 		}
462 
463 		if (SIGISMEMBER(p->p_sigacts->ps_sigignore, sig) ||
464 		    SIGISMEMBER(td->td_sigmask, sig)) {
465 			/* Only allow them in write()/ioctl(). */
466 			PROC_UNLOCK(p);
467 			PGRP_UNLOCK(pg);
468 			return (sig == SIGTTOU ? 0 : EIO);
469 		}
470 
471 		if ((p->p_flag & P_PPWAIT) != 0 ||
472 		    (pg->pg_flags & PGRP_ORPHANED) != 0) {
473 			/* Don't allow the action to happen. */
474 			PROC_UNLOCK(p);
475 			PGRP_UNLOCK(pg);
476 			return (EIO);
477 		}
478 		PROC_UNLOCK(p);
479 
480 		/*
481 		 * Send the signal and sleep until we're the new
482 		 * foreground process group.
483 		 */
484 		if (sig != 0) {
485 			ksiginfo_init(&ksi);
486 			ksi.ksi_code = SI_KERNEL;
487 			ksi.ksi_signo = sig;
488 			sig = 0;
489 		}
490 
491 		pgsignal(pg, ksi.ksi_signo, 1, &ksi);
492 		PGRP_UNLOCK(pg);
493 
494 		error = tty_wait(tp, &tp->t_bgwait);
495 		if (error)
496 			return (error);
497 	}
498 }
499 
500 static int
ttydev_read(struct cdev * dev,struct uio * uio,int ioflag)501 ttydev_read(struct cdev *dev, struct uio *uio, int ioflag)
502 {
503 	struct tty *tp = dev->si_drv1;
504 	int error;
505 
506 	error = ttydev_enter(tp);
507 	if (error)
508 		goto done;
509 	error = ttydisc_read(tp, uio, ioflag);
510 	tty_unlock(tp);
511 
512 	/*
513 	 * The read() call should not throw an error when the device is
514 	 * being destroyed. Silently convert it to an EOF.
515 	 */
516 done:	if (error == ENXIO)
517 		error = 0;
518 	return (error);
519 }
520 
521 static int
ttydev_write(struct cdev * dev,struct uio * uio,int ioflag)522 ttydev_write(struct cdev *dev, struct uio *uio, int ioflag)
523 {
524 	struct tty *tp = dev->si_drv1;
525 	int defer, error;
526 
527 	error = ttydev_enter(tp);
528 	if (error)
529 		return (error);
530 
531 	if (tp->t_termios.c_lflag & TOSTOP) {
532 		error = tty_wait_background(tp, curthread, SIGTTOU);
533 		if (error)
534 			goto done;
535 	}
536 
537 	if (ioflag & IO_NDELAY && tp->t_flags & TF_BUSY_OUT) {
538 		/* Allow non-blocking writes to bypass serialization. */
539 		error = ttydisc_write(tp, uio, ioflag);
540 	} else {
541 		/* Serialize write() calls. */
542 		while (tp->t_flags & TF_BUSY_OUT) {
543 			error = tty_wait(tp, &tp->t_outserwait);
544 			if (error)
545 				goto done;
546 		}
547 
548 		tp->t_flags |= TF_BUSY_OUT;
549 		defer = sigdeferstop(SIGDEFERSTOP_ERESTART);
550 		error = ttydisc_write(tp, uio, ioflag);
551 		sigallowstop(defer);
552 		tp->t_flags &= ~TF_BUSY_OUT;
553 		cv_signal(&tp->t_outserwait);
554 	}
555 
556 done:	tty_unlock(tp);
557 	return (error);
558 }
559 
560 static int
ttydev_ioctl(struct cdev * dev,u_long cmd,caddr_t data,int fflag,struct thread * td)561 ttydev_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int fflag,
562     struct thread *td)
563 {
564 	struct tty *tp = dev->si_drv1;
565 	int error;
566 
567 	error = ttydev_enter(tp);
568 	if (error)
569 		return (error);
570 
571 	switch (cmd) {
572 	case TIOCCBRK:
573 	case TIOCCONS:
574 	case TIOCDRAIN:
575 	case TIOCEXCL:
576 	case TIOCFLUSH:
577 	case TIOCNXCL:
578 	case TIOCSBRK:
579 	case TIOCSCTTY:
580 	case TIOCSETA:
581 	case TIOCSETAF:
582 	case TIOCSETAW:
583 	case TIOCSPGRP:
584 	case TIOCSTART:
585 	case TIOCSTAT:
586 	case TIOCSTI:
587 	case TIOCSTOP:
588 	case TIOCSWINSZ:
589 #if 0
590 	case TIOCSDRAINWAIT:
591 	case TIOCSETD:
592 #endif
593 #ifdef COMPAT_43TTY
594 	case  TIOCLBIC:
595 	case  TIOCLBIS:
596 	case  TIOCLSET:
597 	case  TIOCSETC:
598 	case OTIOCSETD:
599 	case  TIOCSETN:
600 	case  TIOCSETP:
601 	case  TIOCSLTC:
602 #endif /* COMPAT_43TTY */
603 		/*
604 		 * If the ioctl() causes the TTY to be modified, let it
605 		 * wait in the background.
606 		 */
607 		error = tty_wait_background(tp, curthread, SIGTTOU);
608 		if (error)
609 			goto done;
610 	}
611 
612 	if (cmd == TIOCSETA || cmd == TIOCSETAW || cmd == TIOCSETAF) {
613 		struct termios *old = &tp->t_termios;
614 		struct termios *new = (struct termios *)data;
615 		struct termios *lock = TTY_CALLOUT(tp, dev) ?
616 		    &tp->t_termios_lock_out : &tp->t_termios_lock_in;
617 		int cc;
618 
619 		/*
620 		 * Lock state devices.  Just overwrite the values of the
621 		 * commands that are currently in use.
622 		 */
623 		new->c_iflag = (old->c_iflag & lock->c_iflag) |
624 		    (new->c_iflag & ~lock->c_iflag);
625 		new->c_oflag = (old->c_oflag & lock->c_oflag) |
626 		    (new->c_oflag & ~lock->c_oflag);
627 		new->c_cflag = (old->c_cflag & lock->c_cflag) |
628 		    (new->c_cflag & ~lock->c_cflag);
629 		new->c_lflag = (old->c_lflag & lock->c_lflag) |
630 		    (new->c_lflag & ~lock->c_lflag);
631 		for (cc = 0; cc < NCCS; ++cc)
632 			if (lock->c_cc[cc])
633 				new->c_cc[cc] = old->c_cc[cc];
634 		if (lock->c_ispeed)
635 			new->c_ispeed = old->c_ispeed;
636 		if (lock->c_ospeed)
637 			new->c_ospeed = old->c_ospeed;
638 	}
639 
640 	error = tty_ioctl(tp, cmd, data, fflag, td);
641 done:	tty_unlock(tp);
642 
643 	return (error);
644 }
645 
646 static int
ttydev_poll(struct cdev * dev,int events,struct thread * td)647 ttydev_poll(struct cdev *dev, int events, struct thread *td)
648 {
649 	struct tty *tp = dev->si_drv1;
650 	int error, revents = 0;
651 
652 	error = ttydev_enter(tp);
653 	if (error)
654 		return ((events & (POLLIN|POLLRDNORM)) | POLLHUP);
655 
656 	if (events & (POLLIN|POLLRDNORM)) {
657 		/* See if we can read something. */
658 		if (ttydisc_read_poll(tp) > 0)
659 			revents |= events & (POLLIN|POLLRDNORM);
660 	}
661 
662 	if (tp->t_flags & TF_ZOMBIE) {
663 		/* Hangup flag on zombie state. */
664 		revents |= POLLHUP;
665 	} else if (events & (POLLOUT|POLLWRNORM)) {
666 		/* See if we can write something. */
667 		if (ttydisc_write_poll(tp) > 0)
668 			revents |= events & (POLLOUT|POLLWRNORM);
669 	}
670 
671 	if (revents == 0) {
672 		if (events & (POLLIN|POLLRDNORM))
673 			selrecord(td, &tp->t_inpoll);
674 		if (events & (POLLOUT|POLLWRNORM))
675 			selrecord(td, &tp->t_outpoll);
676 	}
677 
678 	tty_unlock(tp);
679 
680 	return (revents);
681 }
682 
683 static int
ttydev_mmap(struct cdev * dev,vm_ooffset_t offset,vm_paddr_t * paddr,int nprot,vm_memattr_t * memattr)684 ttydev_mmap(struct cdev *dev, vm_ooffset_t offset, vm_paddr_t *paddr,
685     int nprot, vm_memattr_t *memattr)
686 {
687 	struct tty *tp = dev->si_drv1;
688 	int error;
689 
690 	/* Handle mmap() through the driver. */
691 
692 	error = ttydev_enter(tp);
693 	if (error)
694 		return (-1);
695 	error = ttydevsw_mmap(tp, offset, paddr, nprot, memattr);
696 	tty_unlock(tp);
697 
698 	return (error);
699 }
700 
701 /*
702  * kqueue support.
703  */
704 
705 static void
tty_kqops_read_detach(struct knote * kn)706 tty_kqops_read_detach(struct knote *kn)
707 {
708 	struct tty *tp = kn->kn_hook;
709 
710 	knlist_remove(&tp->t_inpoll.si_note, kn, 0);
711 }
712 
713 static int
tty_kqops_read_event(struct knote * kn,long hint __unused)714 tty_kqops_read_event(struct knote *kn, long hint __unused)
715 {
716 	struct tty *tp = kn->kn_hook;
717 
718 	tty_assert_locked(tp);
719 
720 	if (tty_gone(tp) || tp->t_flags & TF_ZOMBIE) {
721 		kn->kn_flags |= EV_EOF;
722 		return (1);
723 	} else {
724 		kn->kn_data = ttydisc_read_poll(tp);
725 		return (kn->kn_data > 0);
726 	}
727 }
728 
729 static void
tty_kqops_write_detach(struct knote * kn)730 tty_kqops_write_detach(struct knote *kn)
731 {
732 	struct tty *tp = kn->kn_hook;
733 
734 	knlist_remove(&tp->t_outpoll.si_note, kn, 0);
735 }
736 
737 static int
tty_kqops_write_event(struct knote * kn,long hint __unused)738 tty_kqops_write_event(struct knote *kn, long hint __unused)
739 {
740 	struct tty *tp = kn->kn_hook;
741 
742 	tty_assert_locked(tp);
743 
744 	if (tty_gone(tp)) {
745 		kn->kn_flags |= EV_EOF;
746 		return (1);
747 	} else {
748 		kn->kn_data = ttydisc_write_poll(tp);
749 		return (kn->kn_data > 0);
750 	}
751 }
752 
753 static const struct filterops tty_kqops_read = {
754 	.f_isfd = 1,
755 	.f_detach = tty_kqops_read_detach,
756 	.f_event = tty_kqops_read_event,
757 	.f_copy = knote_triv_copy,
758 };
759 
760 static const struct filterops tty_kqops_write = {
761 	.f_isfd = 1,
762 	.f_detach = tty_kqops_write_detach,
763 	.f_event = tty_kqops_write_event,
764 	.f_copy = knote_triv_copy,
765 };
766 
767 static int
ttydev_kqfilter(struct cdev * dev,struct knote * kn)768 ttydev_kqfilter(struct cdev *dev, struct knote *kn)
769 {
770 	struct tty *tp = dev->si_drv1;
771 	int error;
772 
773 	error = ttydev_enter(tp);
774 	if (error)
775 		return (error);
776 
777 	switch (kn->kn_filter) {
778 	case EVFILT_READ:
779 		kn->kn_hook = tp;
780 		kn->kn_fop = &tty_kqops_read;
781 		knlist_add(&tp->t_inpoll.si_note, kn, 1);
782 		break;
783 	case EVFILT_WRITE:
784 		kn->kn_hook = tp;
785 		kn->kn_fop = &tty_kqops_write;
786 		knlist_add(&tp->t_outpoll.si_note, kn, 1);
787 		break;
788 	default:
789 		error = EINVAL;
790 		break;
791 	}
792 
793 	tty_unlock(tp);
794 	return (error);
795 }
796 
797 static struct cdevsw ttydev_cdevsw = {
798 	.d_version	= D_VERSION,
799 	.d_open		= ttydev_open,
800 	.d_close	= ttydev_close,
801 	.d_read		= ttydev_read,
802 	.d_write	= ttydev_write,
803 	.d_ioctl	= ttydev_ioctl,
804 	.d_kqfilter	= ttydev_kqfilter,
805 	.d_poll		= ttydev_poll,
806 	.d_mmap		= ttydev_mmap,
807 	.d_name		= "ttydev",
808 	.d_flags	= D_TTY,
809 };
810 
811 /*
812  * Init/lock-state devices
813  */
814 
815 static int
ttyil_open(struct cdev * dev,int oflags __unused,int devtype __unused,struct thread * td)816 ttyil_open(struct cdev *dev, int oflags __unused, int devtype __unused,
817     struct thread *td)
818 {
819 	struct tty *tp;
820 	int error;
821 
822 	tp = dev->si_drv1;
823 	error = 0;
824 	tty_lock(tp);
825 	if (tty_gone(tp))
826 		error = ENODEV;
827 	tty_unlock(tp);
828 
829 	return (error);
830 }
831 
832 static int
ttyil_close(struct cdev * dev __unused,int flag __unused,int mode __unused,struct thread * td __unused)833 ttyil_close(struct cdev *dev __unused, int flag __unused, int mode __unused,
834     struct thread *td __unused)
835 {
836 
837 	return (0);
838 }
839 
840 static int
ttyil_rdwr(struct cdev * dev __unused,struct uio * uio __unused,int ioflag __unused)841 ttyil_rdwr(struct cdev *dev __unused, struct uio *uio __unused,
842     int ioflag __unused)
843 {
844 
845 	return (ENODEV);
846 }
847 
848 static int
ttyil_ioctl(struct cdev * dev,u_long cmd,caddr_t data,int fflag,struct thread * td)849 ttyil_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int fflag,
850     struct thread *td)
851 {
852 	struct tty *tp = dev->si_drv1;
853 	int error;
854 
855 	tty_lock(tp);
856 	if (tty_gone(tp)) {
857 		error = ENODEV;
858 		goto done;
859 	}
860 
861 	error = ttydevsw_cioctl(tp, dev2unit(dev), cmd, data, td);
862 	if (error != ENOIOCTL)
863 		goto done;
864 	error = 0;
865 
866 	switch (cmd) {
867 	case TIOCGETA:
868 		/* Obtain terminal flags through tcgetattr(). */
869 		*(struct termios*)data = *(struct termios*)dev->si_drv2;
870 		break;
871 	case TIOCSETA:
872 		/* Set terminal flags through tcsetattr(). */
873 		error = priv_check(td, PRIV_TTY_SETA);
874 		if (error)
875 			break;
876 		*(struct termios*)dev->si_drv2 = *(struct termios*)data;
877 		break;
878 	case TIOCGETD:
879 		*(int *)data = TTYDISC;
880 		break;
881 	case TIOCGWINSZ:
882 		bzero(data, sizeof(struct winsize));
883 		break;
884 	default:
885 		error = ENOTTY;
886 	}
887 
888 done:	tty_unlock(tp);
889 	return (error);
890 }
891 
892 static struct cdevsw ttyil_cdevsw = {
893 	.d_version	= D_VERSION,
894 	.d_open		= ttyil_open,
895 	.d_close	= ttyil_close,
896 	.d_read		= ttyil_rdwr,
897 	.d_write	= ttyil_rdwr,
898 	.d_ioctl	= ttyil_ioctl,
899 	.d_name		= "ttyil",
900 	.d_flags	= D_TTY,
901 };
902 
903 static void
tty_init_termios(struct tty * tp)904 tty_init_termios(struct tty *tp)
905 {
906 	struct termios *t = &tp->t_termios_init_in;
907 
908 	t->c_cflag = TTYDEF_CFLAG;
909 	t->c_iflag = TTYDEF_IFLAG;
910 	t->c_lflag = TTYDEF_LFLAG;
911 	t->c_oflag = TTYDEF_OFLAG;
912 	t->c_ispeed = TTYDEF_SPEED;
913 	t->c_ospeed = TTYDEF_SPEED;
914 	memcpy(&t->c_cc, ttydefchars, sizeof ttydefchars);
915 
916 	tp->t_termios_init_out = *t;
917 }
918 
919 void
tty_init_console(struct tty * tp,speed_t s)920 tty_init_console(struct tty *tp, speed_t s)
921 {
922 	struct termios *ti = &tp->t_termios_init_in;
923 	struct termios *to = &tp->t_termios_init_out;
924 
925 	if (s != 0) {
926 		ti->c_ispeed = ti->c_ospeed = s;
927 		to->c_ispeed = to->c_ospeed = s;
928 	}
929 
930 	ti->c_cflag |= CLOCAL;
931 	to->c_cflag |= CLOCAL;
932 }
933 
934 /*
935  * Standard device routine implementations, mostly meant for
936  * pseudo-terminal device drivers. When a driver creates a new terminal
937  * device class, missing routines are patched.
938  */
939 
940 static int
ttydevsw_defopen(struct tty * tp __unused)941 ttydevsw_defopen(struct tty *tp __unused)
942 {
943 
944 	return (0);
945 }
946 
947 static void
ttydevsw_defclose(struct tty * tp __unused)948 ttydevsw_defclose(struct tty *tp __unused)
949 {
950 
951 }
952 
953 static void
ttydevsw_defoutwakeup(struct tty * tp __unused)954 ttydevsw_defoutwakeup(struct tty *tp __unused)
955 {
956 
957 	panic("Terminal device has output, while not implemented");
958 }
959 
960 static void
ttydevsw_definwakeup(struct tty * tp __unused)961 ttydevsw_definwakeup(struct tty *tp __unused)
962 {
963 
964 }
965 
966 static int
ttydevsw_defioctl(struct tty * tp __unused,u_long cmd __unused,caddr_t data __unused,struct thread * td __unused)967 ttydevsw_defioctl(struct tty *tp __unused, u_long cmd __unused,
968     caddr_t data __unused, struct thread *td __unused)
969 {
970 
971 	return (ENOIOCTL);
972 }
973 
974 static int
ttydevsw_defcioctl(struct tty * tp __unused,int unit __unused,u_long cmd __unused,caddr_t data __unused,struct thread * td __unused)975 ttydevsw_defcioctl(struct tty *tp __unused, int unit __unused,
976     u_long cmd __unused, caddr_t data __unused, struct thread *td __unused)
977 {
978 
979 	return (ENOIOCTL);
980 }
981 
982 static int
ttydevsw_defparam(struct tty * tp __unused,struct termios * t)983 ttydevsw_defparam(struct tty *tp __unused, struct termios *t)
984 {
985 
986 	/*
987 	 * Allow the baud rate to be adjusted for pseudo-devices, but at
988 	 * least restrict it to 115200 to prevent excessive buffer
989 	 * usage.  Also disallow 0, to prevent foot shooting.
990 	 */
991 	if (t->c_ispeed < B50)
992 		t->c_ispeed = B50;
993 	else if (t->c_ispeed > B115200)
994 		t->c_ispeed = B115200;
995 	if (t->c_ospeed < B50)
996 		t->c_ospeed = B50;
997 	else if (t->c_ospeed > B115200)
998 		t->c_ospeed = B115200;
999 	t->c_cflag |= CREAD;
1000 
1001 	return (0);
1002 }
1003 
1004 static int
ttydevsw_defmodem(struct tty * tp __unused,int sigon __unused,int sigoff __unused)1005 ttydevsw_defmodem(struct tty *tp __unused, int sigon __unused,
1006     int sigoff __unused)
1007 {
1008 
1009 	/* Simulate a carrier to make the TTY layer happy. */
1010 	return (SER_DCD);
1011 }
1012 
1013 static int
ttydevsw_defmmap(struct tty * tp __unused,vm_ooffset_t offset __unused,vm_paddr_t * paddr __unused,int nprot __unused,vm_memattr_t * memattr __unused)1014 ttydevsw_defmmap(struct tty *tp __unused, vm_ooffset_t offset __unused,
1015     vm_paddr_t *paddr __unused, int nprot __unused,
1016     vm_memattr_t *memattr __unused)
1017 {
1018 
1019 	return (-1);
1020 }
1021 
1022 static void
ttydevsw_defpktnotify(struct tty * tp __unused,char event __unused)1023 ttydevsw_defpktnotify(struct tty *tp __unused, char event __unused)
1024 {
1025 
1026 }
1027 
1028 static void
ttydevsw_deffree(void * softc __unused)1029 ttydevsw_deffree(void *softc __unused)
1030 {
1031 
1032 	panic("Terminal device freed without a free-handler");
1033 }
1034 
1035 static bool
ttydevsw_defbusy(struct tty * tp __unused)1036 ttydevsw_defbusy(struct tty *tp __unused)
1037 {
1038 
1039 	return (FALSE);
1040 }
1041 
1042 /*
1043  * TTY allocation and deallocation. TTY devices can be deallocated when
1044  * the driver doesn't use it anymore, when the TTY isn't a session's
1045  * controlling TTY and when the device node isn't opened through devfs.
1046  */
1047 
1048 struct tty *
tty_alloc(struct ttydevsw * tsw,void * sc)1049 tty_alloc(struct ttydevsw *tsw, void *sc)
1050 {
1051 
1052 	return (tty_alloc_mutex(tsw, sc, NULL));
1053 }
1054 
1055 struct tty *
tty_alloc_mutex(struct ttydevsw * tsw,void * sc,struct mtx * mutex)1056 tty_alloc_mutex(struct ttydevsw *tsw, void *sc, struct mtx *mutex)
1057 {
1058 	struct tty *tp;
1059 
1060 	/* Make sure the driver defines all routines. */
1061 #define PATCH_FUNC(x) do {				\
1062 	if (tsw->tsw_ ## x == NULL)			\
1063 		tsw->tsw_ ## x = ttydevsw_def ## x;	\
1064 } while (0)
1065 	PATCH_FUNC(open);
1066 	PATCH_FUNC(close);
1067 	PATCH_FUNC(outwakeup);
1068 	PATCH_FUNC(inwakeup);
1069 	PATCH_FUNC(ioctl);
1070 	PATCH_FUNC(cioctl);
1071 	PATCH_FUNC(param);
1072 	PATCH_FUNC(modem);
1073 	PATCH_FUNC(mmap);
1074 	PATCH_FUNC(pktnotify);
1075 	PATCH_FUNC(free);
1076 	PATCH_FUNC(busy);
1077 #undef PATCH_FUNC
1078 
1079 	tp = malloc(sizeof(struct tty) + TTY_PRBUF_SIZE, M_TTY,
1080 	    M_WAITOK | M_ZERO);
1081 	tp->t_prbufsz = TTY_PRBUF_SIZE;
1082 	tp->t_devsw = tsw;
1083 	tp->t_devswsoftc = sc;
1084 	tp->t_flags = tsw->tsw_flags;
1085 	tp->t_drainwait = tty_drainwait;
1086 
1087 	tty_init_termios(tp);
1088 
1089 	cv_init(&tp->t_inwait, "ttyin");
1090 	cv_init(&tp->t_outwait, "ttyout");
1091 	cv_init(&tp->t_outserwait, "ttyosr");
1092 	cv_init(&tp->t_bgwait, "ttybg");
1093 	cv_init(&tp->t_dcdwait, "ttydcd");
1094 
1095 	/* Allow drivers to use a custom mutex to lock the TTY. */
1096 	if (mutex != NULL) {
1097 		tp->t_mtx = mutex;
1098 	} else {
1099 		tp->t_mtx = &tp->t_mtxobj;
1100 		mtx_init(&tp->t_mtxobj, "ttymtx", NULL, MTX_DEF);
1101 	}
1102 
1103 	knlist_init_mtx(&tp->t_inpoll.si_note, tp->t_mtx);
1104 	knlist_init_mtx(&tp->t_outpoll.si_note, tp->t_mtx);
1105 
1106 	return (tp);
1107 }
1108 
1109 static void
tty_dealloc(void * arg)1110 tty_dealloc(void *arg)
1111 {
1112 	struct tty *tp = arg;
1113 
1114 	/*
1115 	 * ttyydev_leave() usually frees the i/o queues earlier, but it is
1116 	 * not always called between queue allocation and here.  The queues
1117 	 * may be allocated by ioctls on a pty control device without the
1118 	 * corresponding pty slave device ever being open, or after it is
1119 	 * closed.
1120 	 */
1121 	ttyinq_free(&tp->t_inq);
1122 	ttyoutq_free(&tp->t_outq);
1123 	seldrain(&tp->t_inpoll);
1124 	seldrain(&tp->t_outpoll);
1125 	knlist_clear(&tp->t_inpoll.si_note, 0);
1126 	knlist_clear(&tp->t_outpoll.si_note, 0);
1127 	knlist_destroy(&tp->t_inpoll.si_note);
1128 	knlist_destroy(&tp->t_outpoll.si_note);
1129 
1130 	cv_destroy(&tp->t_inwait);
1131 	cv_destroy(&tp->t_outwait);
1132 	cv_destroy(&tp->t_bgwait);
1133 	cv_destroy(&tp->t_dcdwait);
1134 	cv_destroy(&tp->t_outserwait);
1135 
1136 	if (tp->t_mtx == &tp->t_mtxobj)
1137 		mtx_destroy(&tp->t_mtxobj);
1138 	ttydevsw_free(tp);
1139 	free(tp, M_TTY);
1140 }
1141 
1142 static void
tty_rel_free(struct tty * tp)1143 tty_rel_free(struct tty *tp)
1144 {
1145 	struct cdev *dev;
1146 
1147 	tty_assert_locked(tp);
1148 
1149 #define	TF_ACTIVITY	(TF_GONE|TF_OPENED|TF_HOOK|TF_OPENCLOSE)
1150 	if (tp->t_sessioncnt != 0 || (tp->t_flags & TF_ACTIVITY) != TF_GONE) {
1151 		/* TTY is still in use. */
1152 		tty_unlock(tp);
1153 		return;
1154 	}
1155 
1156 	/* Stop asynchronous I/O. */
1157 	funsetown(&tp->t_sigio);
1158 
1159 	/* TTY can be deallocated. */
1160 	dev = tp->t_dev;
1161 	tp->t_dev = NULL;
1162 	tty_unlock(tp);
1163 
1164 	if (dev != NULL) {
1165 		sx_xlock(&tty_list_sx);
1166 		TAILQ_REMOVE(&tty_list, tp, t_list);
1167 		tty_list_count--;
1168 		sx_xunlock(&tty_list_sx);
1169 		destroy_dev_sched_cb(dev, tty_dealloc, tp);
1170 	}
1171 }
1172 
1173 void
tty_rel_pgrp(struct tty * tp,struct pgrp * pg)1174 tty_rel_pgrp(struct tty *tp, struct pgrp *pg)
1175 {
1176 
1177 	MPASS(tp->t_sessioncnt > 0);
1178 	tty_assert_locked(tp);
1179 
1180 	if (tp->t_pgrp == pg)
1181 		tp->t_pgrp = NULL;
1182 
1183 	tty_unlock(tp);
1184 }
1185 
1186 void
tty_rel_sess(struct tty * tp,struct session * sess)1187 tty_rel_sess(struct tty *tp, struct session *sess)
1188 {
1189 
1190 	MPASS(tp->t_sessioncnt > 0);
1191 
1192 	/* Current session has left. */
1193 	if (tp->t_session == sess) {
1194 		tp->t_session = NULL;
1195 		MPASS(tp->t_pgrp == NULL);
1196 	}
1197 	tp->t_sessioncnt--;
1198 	tty_rel_free(tp);
1199 }
1200 
1201 void
tty_rel_gone(struct tty * tp)1202 tty_rel_gone(struct tty *tp)
1203 {
1204 
1205 	tty_assert_locked(tp);
1206 	MPASS(!tty_gone(tp));
1207 
1208 	/* Simulate carrier removal. */
1209 	ttydisc_modem(tp, 0);
1210 
1211 	/* Wake up all blocked threads. */
1212 	tty_wakeup(tp, FREAD|FWRITE);
1213 	cv_broadcast(&tp->t_bgwait);
1214 	cv_broadcast(&tp->t_dcdwait);
1215 
1216 	tp->t_flags |= TF_GONE;
1217 	tty_rel_free(tp);
1218 }
1219 
1220 static int
tty_drop_ctty(struct tty * tp,struct proc * p)1221 tty_drop_ctty(struct tty *tp, struct proc *p)
1222 {
1223 	struct session *session;
1224 	struct vnode *vp;
1225 
1226 	/*
1227 	 * This looks terrible, but it's generally safe as long as the tty
1228 	 * hasn't gone away while we had the lock dropped.  All of our sanity
1229 	 * checking that this operation is OK happens after we've picked it back
1230 	 * up, so other state changes are generally not fatal and the potential
1231 	 * for this particular operation to happen out-of-order in a
1232 	 * multithreaded scenario is likely a non-issue.
1233 	 */
1234 	tty_unlock(tp);
1235 	sx_xlock(&proctree_lock);
1236 	tty_lock(tp);
1237 	if (tty_gone(tp)) {
1238 		sx_xunlock(&proctree_lock);
1239 		return (ENODEV);
1240 	}
1241 
1242 	/*
1243 	 * If the session doesn't have a controlling TTY, or if we weren't
1244 	 * invoked on the controlling TTY, we'll return ENOIOCTL as we've
1245 	 * historically done.
1246 	 */
1247 	session = p->p_session;
1248 	if (session->s_ttyp == NULL || session->s_ttyp != tp) {
1249 		sx_xunlock(&proctree_lock);
1250 		return (ENOTTY);
1251 	}
1252 
1253 	if (!SESS_LEADER(p)) {
1254 		sx_xunlock(&proctree_lock);
1255 		return (EPERM);
1256 	}
1257 
1258 	PROC_LOCK(p);
1259 	SESS_LOCK(session);
1260 	vp = session->s_ttyvp;
1261 	session->s_ttyp = NULL;
1262 	session->s_ttyvp = NULL;
1263 	session->s_ttydp = NULL;
1264 	SESS_UNLOCK(session);
1265 
1266 	tp->t_sessioncnt--;
1267 	p->p_flag &= ~P_CONTROLT;
1268 	PROC_UNLOCK(p);
1269 	sx_xunlock(&proctree_lock);
1270 
1271 	/*
1272 	 * If we did have a vnode, release our reference.  Ordinarily we manage
1273 	 * these at the devfs layer, but we can't necessarily know that we were
1274 	 * invoked on the vnode referenced in the session (i.e. the vnode we
1275 	 * hold a reference to).  We explicitly don't check VBAD/VIRF_DOOMED here
1276 	 * to avoid a vnode leak -- in circumstances elsewhere where we'd hit a
1277 	 * VIRF_DOOMED vnode, release has been deferred until the controlling TTY
1278 	 * is either changed or released.
1279 	 */
1280 	if (vp != NULL)
1281 		devfs_ctty_unref(vp);
1282 	return (0);
1283 }
1284 
1285 /*
1286  * Exposing information about current TTY's through sysctl
1287  */
1288 
1289 static void
tty_to_xtty(struct tty * tp,struct xtty * xt)1290 tty_to_xtty(struct tty *tp, struct xtty *xt)
1291 {
1292 
1293 	tty_assert_locked(tp);
1294 
1295 	memset(xt, 0, sizeof(*xt));
1296 	xt->xt_size = sizeof(struct xtty);
1297 	xt->xt_insize = ttyinq_getsize(&tp->t_inq);
1298 	xt->xt_incc = ttyinq_bytescanonicalized(&tp->t_inq);
1299 	xt->xt_inlc = ttyinq_bytesline(&tp->t_inq);
1300 	xt->xt_inlow = tp->t_inlow;
1301 	xt->xt_outsize = ttyoutq_getsize(&tp->t_outq);
1302 	xt->xt_outcc = ttyoutq_bytesused(&tp->t_outq);
1303 	xt->xt_outlow = tp->t_outlow;
1304 	xt->xt_column = tp->t_column;
1305 	xt->xt_pgid = tp->t_pgrp ? tp->t_pgrp->pg_id : 0;
1306 	xt->xt_sid = tp->t_session ? tp->t_session->s_sid : 0;
1307 	xt->xt_flags = tp->t_flags;
1308 	xt->xt_dev = tp->t_dev ? dev2udev(tp->t_dev) : (uint32_t)NODEV;
1309 }
1310 
1311 static int
sysctl_kern_ttys(SYSCTL_HANDLER_ARGS)1312 sysctl_kern_ttys(SYSCTL_HANDLER_ARGS)
1313 {
1314 	unsigned long lsize;
1315 	struct thread *td = curthread;
1316 	struct xtty *xtlist, *xt;
1317 	struct tty *tp;
1318 	struct proc *p;
1319 	int error;
1320 	bool cansee;
1321 
1322 	sx_slock(&tty_list_sx);
1323 	lsize = tty_list_count * sizeof(struct xtty);
1324 	if (lsize == 0) {
1325 		sx_sunlock(&tty_list_sx);
1326 		return (0);
1327 	}
1328 
1329 	xtlist = xt = malloc(lsize, M_TTY, M_WAITOK);
1330 
1331 	TAILQ_FOREACH(tp, &tty_list, t_list) {
1332 		tty_lock(tp);
1333 		if (tp->t_session != NULL &&
1334 		    (p = atomic_load_ptr(&tp->t_session->s_leader)) != NULL) {
1335 			PROC_LOCK(p);
1336 			cansee = (p_cansee(td, p) == 0);
1337 			PROC_UNLOCK(p);
1338 		} else {
1339 			cansee = !jailed(td->td_ucred);
1340 		}
1341 		if (cansee) {
1342 			tty_to_xtty(tp, xt);
1343 			xt++;
1344 		}
1345 		tty_unlock(tp);
1346 	}
1347 	sx_sunlock(&tty_list_sx);
1348 
1349 	lsize = (xt - xtlist) * sizeof(struct xtty);
1350 	if (lsize > 0) {
1351 		error = SYSCTL_OUT(req, xtlist, lsize);
1352 	} else {
1353 		error = 0;
1354 	}
1355 	free(xtlist, M_TTY);
1356 	return (error);
1357 }
1358 
1359 SYSCTL_PROC(_kern, OID_AUTO, ttys, CTLTYPE_OPAQUE|CTLFLAG_RD|CTLFLAG_MPSAFE,
1360 	0, 0, sysctl_kern_ttys, "S,xtty", "List of TTYs");
1361 
1362 /*
1363  * Device node creation. Device has been set up, now we can expose it to
1364  * the user.
1365  */
1366 
1367 int
tty_makedevf(struct tty * tp,struct ucred * cred,int flags,const char * fmt,...)1368 tty_makedevf(struct tty *tp, struct ucred *cred, int flags,
1369     const char *fmt, ...)
1370 {
1371 	va_list ap;
1372 	struct make_dev_args args;
1373 	struct cdev *dev, *init, *lock, *cua, *cinit, *clock;
1374 	const char *prefix = "tty";
1375 	char name[SPECNAMELEN - 3]; /* for "tty" and "cua". */
1376 	uid_t uid;
1377 	gid_t gid;
1378 	mode_t mode;
1379 	int error;
1380 
1381 	/* Remove "tty" prefix from devices like PTY's. */
1382 	if (tp->t_flags & TF_NOPREFIX)
1383 		prefix = "";
1384 
1385 	va_start(ap, fmt);
1386 	vsnrprintf(name, sizeof name, 32, fmt, ap);
1387 	va_end(ap);
1388 
1389 	if (cred == NULL) {
1390 		/* System device. */
1391 		uid = UID_ROOT;
1392 		gid = GID_WHEEL;
1393 		mode = S_IRUSR|S_IWUSR;
1394 	} else {
1395 		/* User device. */
1396 		uid = cred->cr_ruid;
1397 		gid = GID_TTY;
1398 		mode = S_IRUSR|S_IWUSR|S_IWGRP;
1399 	}
1400 
1401 	flags = flags & TTYMK_CLONING ? MAKEDEV_REF : 0;
1402 	flags |= MAKEDEV_CHECKNAME;
1403 
1404 	/* Master call-in device. */
1405 	make_dev_args_init(&args);
1406 	args.mda_flags = flags;
1407 	args.mda_devsw = &ttydev_cdevsw;
1408 	args.mda_cr = cred;
1409 	args.mda_uid = uid;
1410 	args.mda_gid = gid;
1411 	args.mda_mode = mode;
1412 	args.mda_si_drv1 = tp;
1413 	error = make_dev_s(&args, &dev, "%s%s", prefix, name);
1414 	if (error != 0)
1415 		return (error);
1416 	tp->t_dev = dev;
1417 
1418 	init = lock = cua = cinit = clock = NULL;
1419 
1420 	/* Slave call-in devices. */
1421 	if (tp->t_flags & TF_INITLOCK) {
1422 		args.mda_devsw = &ttyil_cdevsw;
1423 		args.mda_unit = TTYUNIT_INIT;
1424 		args.mda_si_drv1 = tp;
1425 		args.mda_si_drv2 = &tp->t_termios_init_in;
1426 		error = make_dev_s(&args, &init, "%s%s.init", prefix, name);
1427 		if (error != 0)
1428 			goto fail;
1429 		dev_depends(dev, init);
1430 
1431 		args.mda_unit = TTYUNIT_LOCK;
1432 		args.mda_si_drv2 = &tp->t_termios_lock_in;
1433 		error = make_dev_s(&args, &lock, "%s%s.lock", prefix, name);
1434 		if (error != 0)
1435 			goto fail;
1436 		dev_depends(dev, lock);
1437 	}
1438 
1439 	/* Call-out devices. */
1440 	if (tp->t_flags & TF_CALLOUT) {
1441 		make_dev_args_init(&args);
1442 		args.mda_flags = flags;
1443 		args.mda_devsw = &ttydev_cdevsw;
1444 		args.mda_cr = cred;
1445 		args.mda_uid = UID_UUCP;
1446 		args.mda_gid = GID_DIALER;
1447 		args.mda_mode = 0660;
1448 		args.mda_unit = TTYUNIT_CALLOUT;
1449 		args.mda_si_drv1 = tp;
1450 		error = make_dev_s(&args, &cua, "cua%s", name);
1451 		if (error != 0)
1452 			goto fail;
1453 		dev_depends(dev, cua);
1454 
1455 		/* Slave call-out devices. */
1456 		if (tp->t_flags & TF_INITLOCK) {
1457 			args.mda_devsw = &ttyil_cdevsw;
1458 			args.mda_unit = TTYUNIT_CALLOUT | TTYUNIT_INIT;
1459 			args.mda_si_drv2 = &tp->t_termios_init_out;
1460 			error = make_dev_s(&args, &cinit, "cua%s.init", name);
1461 			if (error != 0)
1462 				goto fail;
1463 			dev_depends(dev, cinit);
1464 
1465 			args.mda_unit = TTYUNIT_CALLOUT | TTYUNIT_LOCK;
1466 			args.mda_si_drv2 = &tp->t_termios_lock_out;
1467 			error = make_dev_s(&args, &clock, "cua%s.lock", name);
1468 			if (error != 0)
1469 				goto fail;
1470 			dev_depends(dev, clock);
1471 		}
1472 	}
1473 
1474 	sx_xlock(&tty_list_sx);
1475 	TAILQ_INSERT_TAIL(&tty_list, tp, t_list);
1476 	tty_list_count++;
1477 	sx_xunlock(&tty_list_sx);
1478 
1479 	return (0);
1480 
1481 fail:
1482 	destroy_dev(dev);
1483 	if (init)
1484 		destroy_dev(init);
1485 	if (lock)
1486 		destroy_dev(lock);
1487 	if (cinit)
1488 		destroy_dev(cinit);
1489 	if (clock)
1490 		destroy_dev(clock);
1491 
1492 	return (error);
1493 }
1494 
1495 /*
1496  * Signalling processes.
1497  */
1498 
1499 void
tty_signal_sessleader(struct tty * tp,int sig)1500 tty_signal_sessleader(struct tty *tp, int sig)
1501 {
1502 	struct proc *p;
1503 	struct session *s;
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 	/*
1513 	 * Load s_leader exactly once to avoid race where s_leader is
1514 	 * set to NULL by a concurrent invocation of killjobc() by the
1515 	 * session leader.  Note that we are not holding t_session's
1516 	 * lock for the read.
1517 	 */
1518 	if ((s = tp->t_session) != NULL &&
1519 	    (p = atomic_load_ptr(&s->s_leader)) != NULL) {
1520 		PROC_LOCK(p);
1521 		kern_psignal(p, sig);
1522 		PROC_UNLOCK(p);
1523 	}
1524 }
1525 
1526 void
tty_signal_pgrp(struct tty * tp,int sig)1527 tty_signal_pgrp(struct tty *tp, int sig)
1528 {
1529 	ksiginfo_t ksi;
1530 
1531 	tty_assert_locked(tp);
1532 	MPASS(sig >= 1 && sig < NSIG);
1533 
1534 	/* Make signals start output again. */
1535 	tp->t_flags &= ~TF_STOPPED;
1536 	tp->t_termios.c_lflag &= ~FLUSHO;
1537 
1538 	if (sig == SIGINFO && !(tp->t_termios.c_lflag & NOKERNINFO))
1539 		tty_info(tp);
1540 	if (tp->t_pgrp != NULL) {
1541 		ksiginfo_init(&ksi);
1542 		ksi.ksi_signo = sig;
1543 		ksi.ksi_code = SI_KERNEL;
1544 		PGRP_LOCK(tp->t_pgrp);
1545 		pgsignal(tp->t_pgrp, sig, 1, &ksi);
1546 		PGRP_UNLOCK(tp->t_pgrp);
1547 	}
1548 }
1549 
1550 void
tty_wakeup(struct tty * tp,int flags)1551 tty_wakeup(struct tty *tp, int flags)
1552 {
1553 
1554 	if (tp->t_flags & TF_ASYNC && tp->t_sigio != NULL)
1555 		pgsigio(&tp->t_sigio, SIGIO, (tp->t_session != NULL));
1556 
1557 	if (flags & FWRITE) {
1558 		cv_broadcast(&tp->t_outwait);
1559 		selwakeup(&tp->t_outpoll);
1560 		KNOTE_LOCKED(&tp->t_outpoll.si_note, 0);
1561 	}
1562 	if (flags & FREAD) {
1563 		cv_broadcast(&tp->t_inwait);
1564 		selwakeup(&tp->t_inpoll);
1565 		KNOTE_LOCKED(&tp->t_inpoll.si_note, 0);
1566 	}
1567 }
1568 
1569 int
tty_wait(struct tty * tp,struct cv * cv)1570 tty_wait(struct tty *tp, struct cv *cv)
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_wait_sig(cv, tp->t_mtx);
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 int
tty_timedwait(struct tty * tp,struct cv * cv,int hz)1592 tty_timedwait(struct tty *tp, struct cv *cv, int hz)
1593 {
1594 	int error;
1595 	int revokecnt = tp->t_revokecnt;
1596 
1597 	tty_lock_assert(tp, MA_OWNED|MA_NOTRECURSED);
1598 	MPASS(!tty_gone(tp));
1599 
1600 	error = cv_timedwait_sig(cv, tp->t_mtx, hz);
1601 
1602 	/* Bail out when the device slipped away. */
1603 	if (tty_gone(tp))
1604 		return (ENXIO);
1605 
1606 	/* Restart the system call when we may have been revoked. */
1607 	if (tp->t_revokecnt != revokecnt)
1608 		return (ERESTART);
1609 
1610 	return (error);
1611 }
1612 
1613 void
tty_flush(struct tty * tp,int flags)1614 tty_flush(struct tty *tp, int flags)
1615 {
1616 
1617 	if (flags & FWRITE) {
1618 		tp->t_flags &= ~TF_HIWAT_OUT;
1619 		ttyoutq_flush(&tp->t_outq);
1620 		tty_wakeup(tp, FWRITE);
1621 		if (!tty_gone(tp)) {
1622 			ttydevsw_outwakeup(tp);
1623 			ttydevsw_pktnotify(tp, TIOCPKT_FLUSHWRITE);
1624 		}
1625 	}
1626 	if (flags & FREAD) {
1627 		tty_hiwat_in_unblock(tp);
1628 		ttyinq_flush(&tp->t_inq);
1629 		tty_wakeup(tp, FREAD);
1630 		if (!tty_gone(tp)) {
1631 			ttydevsw_inwakeup(tp);
1632 			ttydevsw_pktnotify(tp, TIOCPKT_FLUSHREAD);
1633 		}
1634 	}
1635 }
1636 
1637 void
tty_set_winsize(struct tty * tp,const struct winsize * wsz)1638 tty_set_winsize(struct tty *tp, const struct winsize *wsz)
1639 {
1640 
1641 	if (memcmp(&tp->t_winsize, wsz, sizeof(*wsz)) == 0)
1642 		return;
1643 	tp->t_winsize = *wsz;
1644 	tty_signal_pgrp(tp, SIGWINCH);
1645 }
1646 
1647 static int
tty_sti_check(struct tty * tp,int fflag,struct thread * td)1648 tty_sti_check(struct tty *tp, int fflag, struct thread *td)
1649 {
1650 	/* Root can bypass all of our constraints. */
1651 	if (priv_check(td, PRIV_TTY_STI) == 0)
1652 		return (0);
1653 
1654 	/* Unprivileged users must have it opened for read. */
1655 	if ((fflag & FREAD) == 0)
1656 		return (EPERM);
1657 
1658 	/* It must also be their controlling tty. */
1659 	if (!tty_is_ctty(tp, td->td_proc))
1660 		return (EACCES);
1661 
1662 	return (0);
1663 }
1664 
1665 static int
tty_generic_ioctl(struct tty * tp,u_long cmd,void * data,int fflag,struct thread * td)1666 tty_generic_ioctl(struct tty *tp, u_long cmd, void *data, int fflag,
1667     struct thread *td)
1668 {
1669 	int error;
1670 
1671 	switch (cmd) {
1672 	/*
1673 	 * Modem commands.
1674 	 * The SER_* and TIOCM_* flags are the same, but one bit
1675 	 * shifted. I don't know why.
1676 	 */
1677 	case TIOCSDTR:
1678 		ttydevsw_modem(tp, SER_DTR, 0);
1679 		return (0);
1680 	case TIOCCDTR:
1681 		ttydevsw_modem(tp, 0, SER_DTR);
1682 		return (0);
1683 	case TIOCMSET: {
1684 		int bits = *(int *)data;
1685 		ttydevsw_modem(tp,
1686 		    (bits & (TIOCM_DTR | TIOCM_RTS)) >> 1,
1687 		    ((~bits) & (TIOCM_DTR | TIOCM_RTS)) >> 1);
1688 		return (0);
1689 	}
1690 	case TIOCMBIS: {
1691 		int bits = *(int *)data;
1692 		ttydevsw_modem(tp, (bits & (TIOCM_DTR | TIOCM_RTS)) >> 1, 0);
1693 		return (0);
1694 	}
1695 	case TIOCMBIC: {
1696 		int bits = *(int *)data;
1697 		ttydevsw_modem(tp, 0, (bits & (TIOCM_DTR | TIOCM_RTS)) >> 1);
1698 		return (0);
1699 	}
1700 	case TIOCMGET:
1701 		*(int *)data = TIOCM_LE + (ttydevsw_modem(tp, 0, 0) << 1);
1702 		return (0);
1703 
1704 	case FIOASYNC:
1705 		if (*(int *)data)
1706 			tp->t_flags |= TF_ASYNC;
1707 		else
1708 			tp->t_flags &= ~TF_ASYNC;
1709 		return (0);
1710 	case FIONBIO:
1711 		/* This device supports non-blocking operation. */
1712 		return (0);
1713 	case FIONREAD:
1714 		*(int *)data = ttydisc_bytesavail(tp);
1715 		return (0);
1716 	case FIONWRITE:
1717 	case TIOCOUTQ:
1718 		*(int *)data = ttyoutq_bytesused(&tp->t_outq);
1719 		return (0);
1720 	case FIOSETOWN:
1721 		if (tp->t_session != NULL && !tty_is_ctty(tp, td->td_proc))
1722 			/* Not allowed to set ownership. */
1723 			return (ENOTTY);
1724 
1725 		/* Temporarily unlock the TTY to set ownership. */
1726 		tty_unlock(tp);
1727 		error = fsetown(*(int *)data, &tp->t_sigio);
1728 		tty_lock(tp);
1729 		return (error);
1730 	case FIOGETOWN:
1731 		if (tp->t_session != NULL && !tty_is_ctty(tp, td->td_proc))
1732 			/* Not allowed to set ownership. */
1733 			return (ENOTTY);
1734 
1735 		/* Get ownership. */
1736 		*(int *)data = fgetown(&tp->t_sigio);
1737 		return (0);
1738 	case TIOCGETA:
1739 		/* Obtain terminal flags through tcgetattr(). */
1740 		*(struct termios*)data = tp->t_termios;
1741 		return (0);
1742 	case TIOCSETA:
1743 	case TIOCSETAW:
1744 	case TIOCSETAF: {
1745 		struct termios *t = data;
1746 		bool canonicalize = false;
1747 
1748 		/*
1749 		 * Who makes up these funny rules? According to POSIX,
1750 		 * input baud rate is set equal to the output baud rate
1751 		 * when zero.
1752 		 */
1753 		if (t->c_ispeed == 0)
1754 			t->c_ispeed = t->c_ospeed;
1755 
1756 		/* Discard any unsupported bits. */
1757 		t->c_iflag &= TTYSUP_IFLAG;
1758 		t->c_oflag &= TTYSUP_OFLAG;
1759 		t->c_lflag &= TTYSUP_LFLAG;
1760 		t->c_cflag &= TTYSUP_CFLAG;
1761 
1762 		/* Set terminal flags through tcsetattr(). */
1763 		if (cmd == TIOCSETAW || cmd == TIOCSETAF) {
1764 			error = tty_drain(tp, 0);
1765 			if (error)
1766 				return (error);
1767 			if (cmd == TIOCSETAF)
1768 				tty_flush(tp, FREAD);
1769 		}
1770 
1771 		/*
1772 		 * Only call param() when the flags really change.
1773 		 */
1774 		if ((t->c_cflag & CIGNORE) == 0 &&
1775 		    (tp->t_termios.c_cflag != t->c_cflag ||
1776 		    ((tp->t_termios.c_iflag ^ t->c_iflag) &
1777 		    (IXON|IXOFF|IXANY)) ||
1778 		    tp->t_termios.c_ispeed != t->c_ispeed ||
1779 		    tp->t_termios.c_ospeed != t->c_ospeed)) {
1780 			error = ttydevsw_param(tp, t);
1781 			if (error)
1782 				return (error);
1783 
1784 			/* XXX: CLOCAL? */
1785 
1786 			tp->t_termios.c_cflag = t->c_cflag & ~CIGNORE;
1787 			tp->t_termios.c_ispeed = t->c_ispeed;
1788 			tp->t_termios.c_ospeed = t->c_ospeed;
1789 
1790 			/* Baud rate has changed - update watermarks. */
1791 			error = tty_watermarks(tp);
1792 			if (error)
1793 				return (error);
1794 		}
1795 
1796 		/*
1797 		 * We'll canonicalize any partial input if we're transitioning
1798 		 * ICANON one way or the other.  If we're going from -ICANON ->
1799 		 * ICANON, then in the worst case scenario we're in the middle
1800 		 * of a line but both ttydisc_read() and FIONREAD will search
1801 		 * for one of our line terminals.
1802 		 */
1803 		if ((t->c_lflag & ICANON) != (tp->t_termios.c_lflag & ICANON))
1804 			canonicalize = true;
1805 		else if (tp->t_termios.c_cc[VEOF] != t->c_cc[VEOF] ||
1806 		    tp->t_termios.c_cc[VEOL] != t->c_cc[VEOL])
1807 			canonicalize = true;
1808 
1809 		/* Copy new non-device driver parameters. */
1810 		tp->t_termios.c_iflag = t->c_iflag;
1811 		tp->t_termios.c_oflag = t->c_oflag;
1812 		tp->t_termios.c_lflag = t->c_lflag;
1813 		memcpy(&tp->t_termios.c_cc, t->c_cc, sizeof t->c_cc);
1814 
1815 		ttydisc_optimize(tp);
1816 
1817 		if (canonicalize)
1818 			ttydisc_canonicalize(tp);
1819 		if ((t->c_lflag & ICANON) == 0) {
1820 			/*
1821 			 * When in non-canonical mode, wake up all
1822 			 * readers. Any partial input has already been
1823 			 * canonicalized above if we were in canonical mode.
1824 			 * VMIN and VTIME could also be adjusted.
1825 			 */
1826 			tty_wakeup(tp, FREAD);
1827 		}
1828 
1829 		/*
1830 		 * For packet mode: notify the PTY consumer that VSTOP
1831 		 * and VSTART may have been changed.
1832 		 */
1833 		if (tp->t_termios.c_iflag & IXON &&
1834 		    tp->t_termios.c_cc[VSTOP] == CTRL('S') &&
1835 		    tp->t_termios.c_cc[VSTART] == CTRL('Q'))
1836 			ttydevsw_pktnotify(tp, TIOCPKT_DOSTOP);
1837 		else
1838 			ttydevsw_pktnotify(tp, TIOCPKT_NOSTOP);
1839 		return (0);
1840 	}
1841 	case TIOCGETD:
1842 		/* For compatibility - we only support TTYDISC. */
1843 		*(int *)data = TTYDISC;
1844 		return (0);
1845 	case TIOCGPGRP:
1846 		if (!tty_is_ctty(tp, td->td_proc))
1847 			return (ENOTTY);
1848 
1849 		if (tp->t_pgrp != NULL)
1850 			*(int *)data = tp->t_pgrp->pg_id;
1851 		else
1852 			*(int *)data = NO_PID;
1853 		return (0);
1854 	case TIOCGSID:
1855 		if (!tty_is_ctty(tp, td->td_proc))
1856 			return (ENOTTY);
1857 
1858 		MPASS(tp->t_session);
1859 		*(int *)data = tp->t_session->s_sid;
1860 		return (0);
1861 	case TIOCNOTTY:
1862 		return (tty_drop_ctty(tp, td->td_proc));
1863 	case TIOCSCTTY: {
1864 		struct proc *p = td->td_proc;
1865 
1866 		/* XXX: This looks awful. */
1867 		tty_unlock(tp);
1868 		sx_xlock(&proctree_lock);
1869 		tty_lock(tp);
1870 
1871 		if (!SESS_LEADER(p)) {
1872 			/* Only the session leader may do this. */
1873 			sx_xunlock(&proctree_lock);
1874 			return (EPERM);
1875 		}
1876 
1877 		if (tp->t_session != NULL && tp->t_session == p->p_session) {
1878 			/* This is already our controlling TTY. */
1879 			sx_xunlock(&proctree_lock);
1880 			return (0);
1881 		}
1882 
1883 		if (p->p_session->s_ttyp != NULL ||
1884 		    (tp->t_session != NULL && tp->t_session->s_ttyvp != NULL &&
1885 		    tp->t_session->s_ttyvp->v_type != VBAD)) {
1886 			/*
1887 			 * There is already a relation between a TTY and
1888 			 * a session, or the caller is not the session
1889 			 * leader.
1890 			 *
1891 			 * Allow the TTY to be stolen when the vnode is
1892 			 * invalid, but the reference to the TTY is
1893 			 * still active.  This allows immediate reuse of
1894 			 * TTYs of which the session leader has been
1895 			 * killed or the TTY revoked.
1896 			 */
1897 			sx_xunlock(&proctree_lock);
1898 			return (EPERM);
1899 		}
1900 
1901 		/* Connect the session to the TTY. */
1902 		tp->t_session = p->p_session;
1903 		tp->t_session->s_ttyp = tp;
1904 		tp->t_sessioncnt++;
1905 
1906 		/* Assign foreground process group. */
1907 		tp->t_pgrp = p->p_pgrp;
1908 		PROC_LOCK(p);
1909 		p->p_flag |= P_CONTROLT;
1910 		PROC_UNLOCK(p);
1911 
1912 		sx_xunlock(&proctree_lock);
1913 		return (0);
1914 	}
1915 	case TIOCSPGRP: {
1916 		struct pgrp *pg;
1917 
1918 		/*
1919 		 * XXX: Temporarily unlock the TTY to locate the process
1920 		 * group. This code would be lot nicer if we would ever
1921 		 * decompose proctree_lock.
1922 		 */
1923 		tty_unlock(tp);
1924 		sx_slock(&proctree_lock);
1925 		pg = pgfind(*(int *)data);
1926 		if (pg != NULL)
1927 			PGRP_UNLOCK(pg);
1928 		if (pg == NULL || pg->pg_session != td->td_proc->p_session) {
1929 			sx_sunlock(&proctree_lock);
1930 			tty_lock(tp);
1931 			return (EPERM);
1932 		}
1933 		tty_lock(tp);
1934 
1935 		/*
1936 		 * Determine if this TTY is the controlling TTY after
1937 		 * relocking the TTY.
1938 		 */
1939 		if (!tty_is_ctty(tp, td->td_proc)) {
1940 			sx_sunlock(&proctree_lock);
1941 			return (ENOTTY);
1942 		}
1943 		tp->t_pgrp = pg;
1944 		sx_sunlock(&proctree_lock);
1945 
1946 		/* Wake up the background process groups. */
1947 		cv_broadcast(&tp->t_bgwait);
1948 		return (0);
1949 	}
1950 	case TIOCFLUSH: {
1951 		int flags = *(int *)data;
1952 
1953 		if (flags == 0)
1954 			flags = (FREAD|FWRITE);
1955 		else
1956 			flags &= (FREAD|FWRITE);
1957 		tty_flush(tp, flags);
1958 		return (0);
1959 	}
1960 	case TIOCDRAIN:
1961 		/* Drain TTY output. */
1962 		return tty_drain(tp, 0);
1963 	case TIOCGDRAINWAIT:
1964 		*(int *)data = tp->t_drainwait;
1965 		return (0);
1966 	case TIOCSDRAINWAIT:
1967 		error = priv_check(td, PRIV_TTY_DRAINWAIT);
1968 		if (error == 0)
1969 			tp->t_drainwait = *(int *)data;
1970 		return (error);
1971 	case TIOCCONS:
1972 		/* Set terminal as console TTY. */
1973 		if (*(int *)data) {
1974 			error = priv_check(td, PRIV_TTY_CONSOLE);
1975 			if (error)
1976 				return (error);
1977 			error = constty_set(tp);
1978 		} else {
1979 			error = constty_clear(tp);
1980 		}
1981 		return (error);
1982 	case TIOCGWINSZ:
1983 		/* Obtain window size. */
1984 		*(struct winsize*)data = tp->t_winsize;
1985 		return (0);
1986 	case TIOCSWINSZ:
1987 		/* Set window size. */
1988 		tty_set_winsize(tp, data);
1989 		return (0);
1990 	case TIOCEXCL:
1991 		tp->t_flags |= TF_EXCLUDE;
1992 		return (0);
1993 	case TIOCNXCL:
1994 		tp->t_flags &= ~TF_EXCLUDE;
1995 		return (0);
1996 	case TIOCSTOP:
1997 		tp->t_flags |= TF_STOPPED;
1998 		ttydevsw_pktnotify(tp, TIOCPKT_STOP);
1999 		return (0);
2000 	case TIOCSTART:
2001 		tp->t_flags &= ~TF_STOPPED;
2002 		tp->t_termios.c_lflag &= ~FLUSHO;
2003 		ttydevsw_outwakeup(tp);
2004 		ttydevsw_pktnotify(tp, TIOCPKT_START);
2005 		return (0);
2006 	case TIOCSTAT:
2007 		tty_info(tp);
2008 		return (0);
2009 	case TIOCSTI:
2010 		error = tty_sti_check(tp, fflag, td);
2011 		if (error != 0)
2012 			return (error);
2013 		ttydisc_rint(tp, *(char *)data, 0);
2014 		ttydisc_rint_done(tp);
2015 		return (0);
2016 	}
2017 
2018 #ifdef COMPAT_43TTY
2019 	return tty_ioctl_compat(tp, cmd, data, fflag, td);
2020 #else /* !COMPAT_43TTY */
2021 	return (ENOIOCTL);
2022 #endif /* COMPAT_43TTY */
2023 }
2024 
2025 int
tty_ioctl(struct tty * tp,u_long cmd,void * data,int fflag,struct thread * td)2026 tty_ioctl(struct tty *tp, u_long cmd, void *data, int fflag, struct thread *td)
2027 {
2028 	int error;
2029 
2030 	tty_assert_locked(tp);
2031 
2032 	if (tty_gone(tp))
2033 		return (ENXIO);
2034 
2035 	error = ttydevsw_ioctl(tp, cmd, data, td);
2036 	if (error == ENOIOCTL)
2037 		error = tty_generic_ioctl(tp, cmd, data, fflag, td);
2038 
2039 	return (error);
2040 }
2041 
2042 dev_t
tty_udev(struct tty * tp)2043 tty_udev(struct tty *tp)
2044 {
2045 
2046 	if (tp->t_dev)
2047 		return (dev2udev(tp->t_dev));
2048 	else
2049 		return (NODEV);
2050 }
2051 
2052 int
tty_checkoutq(struct tty * tp)2053 tty_checkoutq(struct tty *tp)
2054 {
2055 
2056 	/* 256 bytes should be enough to print a log message. */
2057 	return (ttyoutq_bytesleft(&tp->t_outq) >= 256);
2058 }
2059 
2060 void
tty_hiwat_in_block(struct tty * tp)2061 tty_hiwat_in_block(struct tty *tp)
2062 {
2063 
2064 	if ((tp->t_flags & TF_HIWAT_IN) == 0 &&
2065 	    tp->t_termios.c_iflag & IXOFF &&
2066 	    tp->t_termios.c_cc[VSTOP] != _POSIX_VDISABLE) {
2067 		/*
2068 		 * Input flow control. Only enter the high watermark when we
2069 		 * can successfully store the VSTOP character.
2070 		 */
2071 		if (ttyoutq_write_nofrag(&tp->t_outq,
2072 		    &tp->t_termios.c_cc[VSTOP], 1) == 0)
2073 			tp->t_flags |= TF_HIWAT_IN;
2074 	} else {
2075 		/* No input flow control. */
2076 		tp->t_flags |= TF_HIWAT_IN;
2077 	}
2078 }
2079 
2080 void
tty_hiwat_in_unblock(struct tty * tp)2081 tty_hiwat_in_unblock(struct tty *tp)
2082 {
2083 
2084 	if (tp->t_flags & TF_HIWAT_IN &&
2085 	    tp->t_termios.c_iflag & IXOFF &&
2086 	    tp->t_termios.c_cc[VSTART] != _POSIX_VDISABLE) {
2087 		/*
2088 		 * Input flow control. Only leave the high watermark when we
2089 		 * can successfully store the VSTART character.
2090 		 */
2091 		if (ttyoutq_write_nofrag(&tp->t_outq,
2092 		    &tp->t_termios.c_cc[VSTART], 1) == 0)
2093 			tp->t_flags &= ~TF_HIWAT_IN;
2094 	} else {
2095 		/* No input flow control. */
2096 		tp->t_flags &= ~TF_HIWAT_IN;
2097 	}
2098 
2099 	if (!tty_gone(tp))
2100 		ttydevsw_inwakeup(tp);
2101 }
2102 
2103 /*
2104  * TTY hooks interface.
2105  */
2106 
2107 static int
ttyhook_defrint(struct tty * tp,char c,int flags)2108 ttyhook_defrint(struct tty *tp, char c, int flags)
2109 {
2110 
2111 	if (ttyhook_rint_bypass(tp, &c, 1) != 1)
2112 		return (-1);
2113 
2114 	return (0);
2115 }
2116 
2117 int
ttyhook_register(struct tty ** rtp,struct proc * p,int fd,struct ttyhook * th,void * softc)2118 ttyhook_register(struct tty **rtp, struct proc *p, int fd, struct ttyhook *th,
2119     void *softc)
2120 {
2121 	struct tty *tp;
2122 	struct file *fp;
2123 	struct cdev *dev;
2124 	struct cdevsw *cdp;
2125 	struct filedesc *fdp;
2126 	cap_rights_t rights;
2127 	int error, ref;
2128 
2129 	/* Validate the file descriptor. */
2130 	/*
2131 	 * XXX this code inspects a file descriptor from a different process,
2132 	 * but there is no dedicated routine to do it in fd code, making the
2133 	 * ordeal highly questionable.
2134 	 */
2135 	fdp = p->p_fd;
2136 	FILEDESC_SLOCK(fdp);
2137 	error = fget_cap_noref(fdp, fd, cap_rights_init_one(&rights, CAP_TTYHOOK),
2138 	    &fp, NULL);
2139 	if (error == 0 && !fhold(fp))
2140 		error = EBADF;
2141 	FILEDESC_SUNLOCK(fdp);
2142 	if (error != 0)
2143 		return (error);
2144 	if (fp->f_ops == &badfileops) {
2145 		error = EBADF;
2146 		goto done1;
2147 	}
2148 
2149 	/*
2150 	 * Make sure the vnode is bound to a character device.
2151 	 * Unlocked check for the vnode type is ok there, because we
2152 	 * only shall prevent calling devvn_refthread on the file that
2153 	 * never has been opened over a character device.
2154 	 */
2155 	if (fp->f_type != DTYPE_VNODE || fp->f_vnode->v_type != VCHR) {
2156 		error = EINVAL;
2157 		goto done1;
2158 	}
2159 
2160 	/* Make sure it is a TTY. */
2161 	cdp = devvn_refthread(fp->f_vnode, &dev, &ref);
2162 	if (cdp == NULL) {
2163 		error = ENXIO;
2164 		goto done1;
2165 	}
2166 	if (dev != fp->f_data) {
2167 		error = ENXIO;
2168 		goto done2;
2169 	}
2170 	if (cdp != &ttydev_cdevsw) {
2171 		error = ENOTTY;
2172 		goto done2;
2173 	}
2174 	tp = dev->si_drv1;
2175 
2176 	/* Try to attach the hook to the TTY. */
2177 	error = EBUSY;
2178 	tty_lock(tp);
2179 	MPASS((tp->t_hook == NULL) == ((tp->t_flags & TF_HOOK) == 0));
2180 	if (tp->t_flags & TF_HOOK)
2181 		goto done3;
2182 
2183 	tp->t_flags |= TF_HOOK;
2184 	tp->t_hook = th;
2185 	tp->t_hooksoftc = softc;
2186 	*rtp = tp;
2187 	error = 0;
2188 
2189 	/* Maybe we can switch into bypass mode now. */
2190 	ttydisc_optimize(tp);
2191 
2192 	/* Silently convert rint() calls to rint_bypass() when possible. */
2193 	if (!ttyhook_hashook(tp, rint) && ttyhook_hashook(tp, rint_bypass))
2194 		th->th_rint = ttyhook_defrint;
2195 
2196 done3:	tty_unlock(tp);
2197 done2:	dev_relthread(dev, ref);
2198 done1:	fdrop(fp, curthread);
2199 	return (error);
2200 }
2201 
2202 void
ttyhook_unregister(struct tty * tp)2203 ttyhook_unregister(struct tty *tp)
2204 {
2205 
2206 	tty_assert_locked(tp);
2207 	MPASS(tp->t_flags & TF_HOOK);
2208 
2209 	/* Disconnect the hook. */
2210 	tp->t_flags &= ~TF_HOOK;
2211 	tp->t_hook = NULL;
2212 
2213 	/* Maybe we need to leave bypass mode. */
2214 	ttydisc_optimize(tp);
2215 
2216 	/* Maybe deallocate the TTY as well. */
2217 	tty_rel_free(tp);
2218 }
2219 
2220 /*
2221  * /dev/console handling.
2222  */
2223 
2224 static int
ttyconsdev_open(struct cdev * dev,int oflags,int devtype,struct thread * td)2225 ttyconsdev_open(struct cdev *dev, int oflags, int devtype, struct thread *td)
2226 {
2227 	struct tty *tp;
2228 
2229 	/* System has no console device. */
2230 	if (dev_console_filename == NULL)
2231 		return (ENXIO);
2232 
2233 	/* Look up corresponding TTY by device name. */
2234 	sx_slock(&tty_list_sx);
2235 	TAILQ_FOREACH(tp, &tty_list, t_list) {
2236 		if (strcmp(dev_console_filename, tty_devname(tp)) == 0) {
2237 			dev_console->si_drv1 = tp;
2238 			break;
2239 		}
2240 	}
2241 	sx_sunlock(&tty_list_sx);
2242 
2243 	/* System console has no TTY associated. */
2244 	if (dev_console->si_drv1 == NULL)
2245 		return (ENXIO);
2246 
2247 	return (ttydev_open(dev, oflags, devtype, td));
2248 }
2249 
2250 static int
ttyconsdev_write(struct cdev * dev,struct uio * uio,int ioflag)2251 ttyconsdev_write(struct cdev *dev, struct uio *uio, int ioflag)
2252 {
2253 
2254 	log_console(uio);
2255 
2256 	return (ttydev_write(dev, uio, ioflag));
2257 }
2258 
2259 /*
2260  * /dev/console is a little different than normal TTY's.  When opened,
2261  * it determines which TTY to use.  When data gets written to it, it
2262  * will be logged in the kernel message buffer.
2263  */
2264 static struct cdevsw ttyconsdev_cdevsw = {
2265 	.d_version	= D_VERSION,
2266 	.d_open		= ttyconsdev_open,
2267 	.d_close	= ttydev_close,
2268 	.d_read		= ttydev_read,
2269 	.d_write	= ttyconsdev_write,
2270 	.d_ioctl	= ttydev_ioctl,
2271 	.d_kqfilter	= ttydev_kqfilter,
2272 	.d_poll		= ttydev_poll,
2273 	.d_mmap		= ttydev_mmap,
2274 	.d_name		= "ttyconsdev",
2275 	.d_flags	= D_TTY,
2276 };
2277 
2278 static void
ttyconsdev_init(void * unused __unused)2279 ttyconsdev_init(void *unused __unused)
2280 {
2281 
2282 	dev_console = make_dev_credf(MAKEDEV_ETERNAL, &ttyconsdev_cdevsw, 0,
2283 	    NULL, UID_ROOT, GID_WHEEL, 0600, "console");
2284 }
2285 
2286 SYSINIT(tty, SI_SUB_DRIVERS, SI_ORDER_FIRST, ttyconsdev_init, NULL);
2287 
2288 void
ttyconsdev_select(const char * name)2289 ttyconsdev_select(const char *name)
2290 {
2291 
2292 	dev_console_filename = name;
2293 }
2294 
2295 /*
2296  * Debugging routines.
2297  */
2298 
2299 #include "opt_ddb.h"
2300 #ifdef DDB
2301 #include <ddb/ddb.h>
2302 #include <ddb/db_sym.h>
2303 
2304 static const struct {
2305 	int flag;
2306 	char val;
2307 } ttystates[] = {
2308 #if 0
2309 	{ TF_NOPREFIX,		'N' },
2310 #endif
2311 	{ TF_INITLOCK,		'I' },
2312 	{ TF_CALLOUT,		'C' },
2313 
2314 	/* Keep these together -> 'Oi' and 'Oo'. */
2315 	{ TF_OPENED,		'O' },
2316 	{ TF_OPENED_IN,		'i' },
2317 	{ TF_OPENED_OUT,	'o' },
2318 	{ TF_OPENED_CONS,	'c' },
2319 
2320 	{ TF_GONE,		'G' },
2321 	{ TF_OPENCLOSE,		'B' },
2322 	{ TF_ASYNC,		'Y' },
2323 	{ TF_LITERAL,		'L' },
2324 
2325 	/* Keep these together -> 'Hi' and 'Ho'. */
2326 	{ TF_HIWAT,		'H' },
2327 	{ TF_HIWAT_IN,		'i' },
2328 	{ TF_HIWAT_OUT,		'o' },
2329 
2330 	{ TF_STOPPED,		'S' },
2331 	{ TF_EXCLUDE,		'X' },
2332 	{ TF_BYPASS,		'l' },
2333 	{ TF_ZOMBIE,		'Z' },
2334 	{ TF_HOOK,		's' },
2335 
2336 	/* Keep these together -> 'bi' and 'bo'. */
2337 	{ TF_BUSY,		'b' },
2338 	{ TF_BUSY_IN,		'i' },
2339 	{ TF_BUSY_OUT,		'o' },
2340 
2341 	{ 0,			'\0'},
2342 };
2343 
2344 #define	TTY_FLAG_BITS \
2345 	"\20\1NOPREFIX\2INITLOCK\3CALLOUT\4OPENED_IN" \
2346 	"\5OPENED_OUT\6OPENED_CONS\7GONE\10OPENCLOSE" \
2347 	"\11ASYNC\12LITERAL\13HIWAT_IN\14HIWAT_OUT" \
2348 	"\15STOPPED\16EXCLUDE\17BYPASS\20ZOMBIE" \
2349 	"\21HOOK\22BUSY_IN\23BUSY_OUT"
2350 
2351 #define DB_PRINTSYM(name, addr) \
2352 	db_printf("%s  " #name ": ", sep); \
2353 	db_printsym((db_addr_t) addr, DB_STGY_ANY); \
2354 	db_printf("\n");
2355 
2356 static void
_db_show_devsw(const char * sep,const struct ttydevsw * tsw)2357 _db_show_devsw(const char *sep, const struct ttydevsw *tsw)
2358 {
2359 
2360 	db_printf("%sdevsw: ", sep);
2361 	db_printsym((db_addr_t)tsw, DB_STGY_ANY);
2362 	db_printf(" (%p)\n", tsw);
2363 	DB_PRINTSYM(open, tsw->tsw_open);
2364 	DB_PRINTSYM(close, tsw->tsw_close);
2365 	DB_PRINTSYM(outwakeup, tsw->tsw_outwakeup);
2366 	DB_PRINTSYM(inwakeup, tsw->tsw_inwakeup);
2367 	DB_PRINTSYM(ioctl, tsw->tsw_ioctl);
2368 	DB_PRINTSYM(param, tsw->tsw_param);
2369 	DB_PRINTSYM(modem, tsw->tsw_modem);
2370 	DB_PRINTSYM(mmap, tsw->tsw_mmap);
2371 	DB_PRINTSYM(pktnotify, tsw->tsw_pktnotify);
2372 	DB_PRINTSYM(free, tsw->tsw_free);
2373 }
2374 
2375 static void
_db_show_hooks(const char * sep,const struct ttyhook * th)2376 _db_show_hooks(const char *sep, const struct ttyhook *th)
2377 {
2378 
2379 	db_printf("%shook: ", sep);
2380 	db_printsym((db_addr_t)th, DB_STGY_ANY);
2381 	db_printf(" (%p)\n", th);
2382 	if (th == NULL)
2383 		return;
2384 	DB_PRINTSYM(rint, th->th_rint);
2385 	DB_PRINTSYM(rint_bypass, th->th_rint_bypass);
2386 	DB_PRINTSYM(rint_done, th->th_rint_done);
2387 	DB_PRINTSYM(rint_poll, th->th_rint_poll);
2388 	DB_PRINTSYM(getc_inject, th->th_getc_inject);
2389 	DB_PRINTSYM(getc_capture, th->th_getc_capture);
2390 	DB_PRINTSYM(getc_poll, th->th_getc_poll);
2391 	DB_PRINTSYM(close, th->th_close);
2392 }
2393 
2394 static void
_db_show_termios(const char * name,const struct termios * t)2395 _db_show_termios(const char *name, const struct termios *t)
2396 {
2397 
2398 	db_printf("%s: iflag 0x%x oflag 0x%x cflag 0x%x "
2399 	    "lflag 0x%x ispeed %u ospeed %u\n", name,
2400 	    t->c_iflag, t->c_oflag, t->c_cflag, t->c_lflag,
2401 	    t->c_ispeed, t->c_ospeed);
2402 }
2403 
2404 /* DDB command to show TTY statistics. */
DB_SHOW_COMMAND(tty,db_show_tty)2405 DB_SHOW_COMMAND(tty, db_show_tty)
2406 {
2407 	struct tty *tp;
2408 
2409 	if (!have_addr) {
2410 		db_printf("usage: show tty <addr>\n");
2411 		return;
2412 	}
2413 	tp = (struct tty *)addr;
2414 
2415 	db_printf("%p: %s\n", tp, tty_devname(tp));
2416 	db_printf("\tmtx: %p\n", tp->t_mtx);
2417 	db_printf("\tflags: 0x%b\n", tp->t_flags, TTY_FLAG_BITS);
2418 	db_printf("\trevokecnt: %u\n", tp->t_revokecnt);
2419 
2420 	/* Buffering mechanisms. */
2421 	db_printf("\tinq: %p begin %u linestart %u reprint %u end %u "
2422 	    "nblocks %u quota %u\n", &tp->t_inq, tp->t_inq.ti_begin,
2423 	    tp->t_inq.ti_linestart, tp->t_inq.ti_reprint, tp->t_inq.ti_end,
2424 	    tp->t_inq.ti_nblocks, tp->t_inq.ti_quota);
2425 	db_printf("\toutq: %p begin %u end %u nblocks %u quota %u\n",
2426 	    &tp->t_outq, tp->t_outq.to_begin, tp->t_outq.to_end,
2427 	    tp->t_outq.to_nblocks, tp->t_outq.to_quota);
2428 	db_printf("\tinlow: %zu\n", tp->t_inlow);
2429 	db_printf("\toutlow: %zu\n", tp->t_outlow);
2430 	_db_show_termios("\ttermios", &tp->t_termios);
2431 	db_printf("\twinsize: row %u col %u xpixel %u ypixel %u\n",
2432 	    tp->t_winsize.ws_row, tp->t_winsize.ws_col,
2433 	    tp->t_winsize.ws_xpixel, tp->t_winsize.ws_ypixel);
2434 	db_printf("\tcolumn: %u\n", tp->t_column);
2435 	db_printf("\twritepos: %u\n", tp->t_writepos);
2436 	db_printf("\tcompatflags: 0x%x\n", tp->t_compatflags);
2437 
2438 	/* Init/lock-state devices. */
2439 	_db_show_termios("\ttermios_init_in", &tp->t_termios_init_in);
2440 	_db_show_termios("\ttermios_init_out", &tp->t_termios_init_out);
2441 	_db_show_termios("\ttermios_lock_in", &tp->t_termios_lock_in);
2442 	_db_show_termios("\ttermios_lock_out", &tp->t_termios_lock_out);
2443 
2444 	/* Hooks */
2445 	_db_show_devsw("\t", tp->t_devsw);
2446 	_db_show_hooks("\t", tp->t_hook);
2447 
2448 	/* Process info. */
2449 	db_printf("\tpgrp: %p gid %d\n", tp->t_pgrp,
2450 	    tp->t_pgrp ? tp->t_pgrp->pg_id : 0);
2451 	db_printf("\tsession: %p", tp->t_session);
2452 	if (tp->t_session != NULL)
2453 	    db_printf(" count %u leader %p tty %p sid %d login %s",
2454 		tp->t_session->s_count, tp->t_session->s_leader,
2455 		tp->t_session->s_ttyp, tp->t_session->s_sid,
2456 		tp->t_session->s_login);
2457 	db_printf("\n");
2458 	db_printf("\tsessioncnt: %u\n", tp->t_sessioncnt);
2459 	db_printf("\tdevswsoftc: %p\n", tp->t_devswsoftc);
2460 	db_printf("\thooksoftc: %p\n", tp->t_hooksoftc);
2461 	db_printf("\tdev: %p\n", tp->t_dev);
2462 }
2463 
2464 /* DDB command to list TTYs. */
DB_SHOW_ALL_COMMAND(ttys,db_show_all_ttys)2465 DB_SHOW_ALL_COMMAND(ttys, db_show_all_ttys)
2466 {
2467 	struct tty *tp;
2468 	size_t isiz, osiz;
2469 	int i, j;
2470 
2471 	/* Make the output look like `pstat -t'. */
2472 	db_printf("PTR        ");
2473 #if defined(__LP64__)
2474 	db_printf("        ");
2475 #endif
2476 	db_printf("      LINE   INQ  CAN  LIN  LOW  OUTQ  USE  LOW   "
2477 	    "COL  SESS  PGID STATE\n");
2478 
2479 	TAILQ_FOREACH(tp, &tty_list, t_list) {
2480 		isiz = tp->t_inq.ti_nblocks * TTYINQ_DATASIZE;
2481 		osiz = tp->t_outq.to_nblocks * TTYOUTQ_DATASIZE;
2482 
2483 		db_printf("%p %10s %5zu %4u %4u %4zu %5zu %4u %4zu %5u %5d "
2484 		    "%5d ", tp, tty_devname(tp), isiz,
2485 		    tp->t_inq.ti_linestart - tp->t_inq.ti_begin,
2486 		    tp->t_inq.ti_end - tp->t_inq.ti_linestart,
2487 		    isiz - tp->t_inlow, osiz,
2488 		    tp->t_outq.to_end - tp->t_outq.to_begin,
2489 		    osiz - tp->t_outlow, MIN(tp->t_column, 99999),
2490 		    tp->t_session ? tp->t_session->s_sid : 0,
2491 		    tp->t_pgrp ? tp->t_pgrp->pg_id : 0);
2492 
2493 		/* Flag bits. */
2494 		for (i = j = 0; ttystates[i].flag; i++)
2495 			if (tp->t_flags & ttystates[i].flag) {
2496 				db_printf("%c", ttystates[i].val);
2497 				j++;
2498 			}
2499 		if (j == 0)
2500 			db_printf("-");
2501 		db_printf("\n");
2502 	}
2503 }
2504 #endif /* DDB */
2505