tty.c revision 194771
1/*-
2 * Copyright (c) 2008 Ed Schouten <ed@FreeBSD.org>
3 * All rights reserved.
4 *
5 * Portions of this software were developed under sponsorship from Snow
6 * B.V., the Netherlands.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30#include <sys/cdefs.h>
31__FBSDID("$FreeBSD: head/sys/kern/tty.c 194771 2009-06-23 21:43:02Z ed $");
32
33#include "opt_compat.h"
34
35#include <sys/param.h>
36#include <sys/conf.h>
37#include <sys/cons.h>
38#include <sys/fcntl.h>
39#include <sys/file.h>
40#include <sys/filedesc.h>
41#include <sys/filio.h>
42#ifdef COMPAT_43TTY
43#include <sys/ioctl_compat.h>
44#endif /* COMPAT_43TTY */
45#include <sys/kernel.h>
46#include <sys/limits.h>
47#include <sys/malloc.h>
48#include <sys/mount.h>
49#include <sys/poll.h>
50#include <sys/priv.h>
51#include <sys/proc.h>
52#include <sys/serial.h>
53#include <sys/signal.h>
54#include <sys/stat.h>
55#include <sys/sx.h>
56#include <sys/sysctl.h>
57#include <sys/systm.h>
58#include <sys/tty.h>
59#include <sys/ttycom.h>
60#define TTYDEFCHARS
61#include <sys/ttydefaults.h>
62#undef TTYDEFCHARS
63#include <sys/ucred.h>
64#include <sys/vnode.h>
65
66#include <machine/stdarg.h>
67
68static MALLOC_DEFINE(M_TTY, "tty", "tty device");
69
70static void tty_rel_free(struct tty *tp);
71
72static TAILQ_HEAD(, tty) tty_list = TAILQ_HEAD_INITIALIZER(tty_list);
73static struct sx tty_list_sx;
74SX_SYSINIT(tty_list, &tty_list_sx, "tty list");
75static unsigned int tty_list_count = 0;
76
77/* Character device of /dev/console. */
78static struct cdev	*dev_console;
79static const char	*dev_console_filename;
80
81/*
82 * Flags that are supported and stored by this implementation.
83 */
84#define TTYSUP_IFLAG	(IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK|ISTRIP|\
85			INLCR|IGNCR|ICRNL|IXON|IXOFF|IXANY|IMAXBEL)
86#define TTYSUP_OFLAG	(OPOST|ONLCR|TAB3|ONOEOT|OCRNL|ONOCR|ONLRET)
87#define TTYSUP_LFLAG	(ECHOKE|ECHOE|ECHOK|ECHO|ECHONL|ECHOPRT|\
88			ECHOCTL|ISIG|ICANON|ALTWERASE|IEXTEN|TOSTOP|\
89			FLUSHO|NOKERNINFO|NOFLSH)
90#define TTYSUP_CFLAG	(CIGNORE|CSIZE|CSTOPB|CREAD|PARENB|PARODD|\
91			HUPCL|CLOCAL|CCTS_OFLOW|CRTS_IFLOW|CDTR_IFLOW|\
92			CDSR_OFLOW|CCAR_OFLOW)
93
94#define	TTY_CALLOUT(tp,d) ((d) != (tp)->t_dev && (d) != dev_console)
95
96/*
97 * Set TTY buffer sizes.
98 */
99
100#define	TTYBUF_MAX	65536
101
102static void
103tty_watermarks(struct tty *tp)
104{
105	size_t bs;
106
107	/* Provide an input buffer for 0.2 seconds of data. */
108	bs = MIN(tp->t_termios.c_ispeed / 5, TTYBUF_MAX);
109	ttyinq_setsize(&tp->t_inq, tp, bs);
110
111	/* Set low watermark at 10% (when 90% is available). */
112	tp->t_inlow = (ttyinq_getsize(&tp->t_inq) * 9) / 10;
113
114	/* Provide an ouput buffer for 0.2 seconds of data. */
115	bs = MIN(tp->t_termios.c_ospeed / 5, TTYBUF_MAX);
116	ttyoutq_setsize(&tp->t_outq, tp, bs);
117
118	/* Set low watermark at 10% (when 90% is available). */
119	tp->t_outlow = (ttyoutq_getsize(&tp->t_outq) * 9) / 10;
120}
121
122static int
123tty_drain(struct tty *tp)
124{
125	int error;
126
127	if (ttyhook_hashook(tp, getc_inject))
128		/* buffer is inaccessible */
129		return (0);
130
131	while (ttyoutq_bytesused(&tp->t_outq) > 0) {
132		ttydevsw_outwakeup(tp);
133		/* Could be handled synchronously. */
134		if (ttyoutq_bytesused(&tp->t_outq) == 0)
135			return (0);
136
137		/* Wait for data to be drained. */
138		error = tty_wait(tp, &tp->t_outwait);
139		if (error)
140			return (error);
141	}
142
143	return (0);
144}
145
146/*
147 * Though ttydev_enter() and ttydev_leave() seem to be related, they
148 * don't have to be used together. ttydev_enter() is used by the cdev
149 * operations to prevent an actual operation from being processed when
150 * the TTY has been abandoned. ttydev_leave() is used by ttydev_open()
151 * and ttydev_close() to determine whether per-TTY data should be
152 * deallocated.
153 */
154
155static __inline int
156ttydev_enter(struct tty *tp)
157{
158	tty_lock(tp);
159
160	if (tty_gone(tp) || !tty_opened(tp)) {
161		/* Device is already gone. */
162		tty_unlock(tp);
163		return (ENXIO);
164	}
165
166	return (0);
167}
168
169static void
170ttydev_leave(struct tty *tp)
171{
172	tty_lock_assert(tp, MA_OWNED);
173
174	if (tty_opened(tp) || tp->t_flags & TF_OPENCLOSE) {
175		/* Device is still opened somewhere. */
176		tty_unlock(tp);
177		return;
178	}
179
180	tp->t_flags |= TF_OPENCLOSE;
181
182	/* Stop asynchronous I/O. */
183	funsetown(&tp->t_sigio);
184
185	/* Remove console TTY. */
186	if (constty == tp)
187		constty_clear();
188
189	/* Drain any output. */
190	MPASS((tp->t_flags & TF_STOPPED) == 0);
191	if (!tty_gone(tp))
192		tty_drain(tp);
193
194	ttydisc_close(tp);
195
196	/* Destroy associated buffers already. */
197	ttyinq_free(&tp->t_inq);
198	tp->t_inlow = 0;
199	ttyoutq_free(&tp->t_outq);
200	tp->t_outlow = 0;
201
202	knlist_clear(&tp->t_inpoll.si_note, 1);
203	knlist_clear(&tp->t_outpoll.si_note, 1);
204
205	if (!tty_gone(tp))
206		ttydevsw_close(tp);
207
208	tp->t_flags &= ~TF_OPENCLOSE;
209	cv_broadcast(&tp->t_dcdwait);
210	tty_rel_free(tp);
211}
212
213/*
214 * Operations that are exposed through the character device in /dev.
215 */
216static int
217ttydev_open(struct cdev *dev, int oflags, int devtype, struct thread *td)
218{
219	struct tty *tp = dev->si_drv1;
220	int error = 0;
221
222	tty_lock(tp);
223	if (tty_gone(tp)) {
224		/* Device is already gone. */
225		tty_unlock(tp);
226		return (ENXIO);
227	}
228
229	/*
230	 * Block when other processes are currently opening or closing
231	 * the TTY.
232	 */
233	while (tp->t_flags & TF_OPENCLOSE) {
234		error = tty_wait(tp, &tp->t_dcdwait);
235		if (error != 0) {
236			tty_unlock(tp);
237			return (error);
238		}
239	}
240	tp->t_flags |= TF_OPENCLOSE;
241
242	/*
243	 * Make sure the "tty" and "cua" device cannot be opened at the
244	 * same time.
245	 */
246	if (TTY_CALLOUT(tp, dev)) {
247		if (tp->t_flags & TF_OPENED_IN) {
248			error = EBUSY;
249			goto done;
250		}
251	} else {
252		if (tp->t_flags & TF_OPENED_OUT) {
253			error = EBUSY;
254			goto done;
255		}
256	}
257
258	if (tp->t_flags & TF_EXCLUDE && priv_check(td, PRIV_TTY_EXCLUSIVE)) {
259		error = EBUSY;
260		goto done;
261	}
262
263	if (!tty_opened(tp)) {
264		/* Set proper termios flags. */
265		if (TTY_CALLOUT(tp, dev)) {
266			tp->t_termios = tp->t_termios_init_out;
267		} else {
268			tp->t_termios = tp->t_termios_init_in;
269		}
270		ttydevsw_param(tp, &tp->t_termios);
271
272		ttydevsw_modem(tp, SER_DTR|SER_RTS, 0);
273
274		error = ttydevsw_open(tp);
275		if (error != 0)
276			goto done;
277
278		ttydisc_open(tp);
279		tty_watermarks(tp);
280	}
281
282	/* Wait for Carrier Detect. */
283	if (!TTY_CALLOUT(tp, dev) && (oflags & O_NONBLOCK) == 0 &&
284	    (tp->t_termios.c_cflag & CLOCAL) == 0) {
285		while ((ttydevsw_modem(tp, 0, 0) & SER_DCD) == 0) {
286			error = tty_wait(tp, &tp->t_dcdwait);
287			if (error != 0)
288				goto done;
289		}
290	}
291
292	if (dev == dev_console)
293		tp->t_flags |= TF_OPENED_CONS;
294	else if (TTY_CALLOUT(tp, dev))
295		tp->t_flags |= TF_OPENED_OUT;
296	else
297		tp->t_flags |= TF_OPENED_IN;
298
299done:	tp->t_flags &= ~TF_OPENCLOSE;
300	cv_broadcast(&tp->t_dcdwait);
301	ttydev_leave(tp);
302
303	return (error);
304}
305
306static int
307ttydev_close(struct cdev *dev, int fflag, int devtype, struct thread *td)
308{
309	struct tty *tp = dev->si_drv1;
310
311	tty_lock(tp);
312
313	/*
314	 * Don't actually close the device if it is being used as the
315	 * console.
316	 */
317	MPASS((tp->t_flags & TF_OPENED) != TF_OPENED);
318	if (dev == dev_console)
319		tp->t_flags &= ~TF_OPENED_CONS;
320	else
321		tp->t_flags &= ~(TF_OPENED_IN|TF_OPENED_OUT);
322
323	if (tp->t_flags & TF_OPENED) {
324		tty_unlock(tp);
325		return (0);
326	}
327
328	/*
329	 * This can only be called once. The callin and the callout
330	 * devices cannot be opened at the same time.
331	 */
332	tp->t_flags &= ~(TF_EXCLUDE|TF_STOPPED);
333
334	/* Properly wake up threads that are stuck - revoke(). */
335	tp->t_revokecnt++;
336	tty_wakeup(tp, FREAD|FWRITE);
337	cv_broadcast(&tp->t_bgwait);
338	cv_broadcast(&tp->t_dcdwait);
339
340	ttydev_leave(tp);
341
342	return (0);
343}
344
345static __inline int
346tty_is_ctty(struct tty *tp, struct proc *p)
347{
348	tty_lock_assert(tp, MA_OWNED);
349
350	return (p->p_session == tp->t_session && p->p_flag & P_CONTROLT);
351}
352
353static int
354tty_wait_background(struct tty *tp, struct thread *td, int sig)
355{
356	struct proc *p = td->td_proc;
357	struct pgrp *pg;
358	int error;
359
360	MPASS(sig == SIGTTIN || sig == SIGTTOU);
361	tty_lock_assert(tp, MA_OWNED);
362
363	for (;;) {
364		PROC_LOCK(p);
365		/*
366		 * The process should only sleep, when:
367		 * - This terminal is the controling terminal
368		 * - Its process group is not the foreground process
369		 *   group
370		 * - The parent process isn't waiting for the child to
371		 *   exit
372		 * - the signal to send to the process isn't masked
373		 */
374		if (!tty_is_ctty(tp, p) || p->p_pgrp == tp->t_pgrp) {
375			/* Allow the action to happen. */
376			PROC_UNLOCK(p);
377			return (0);
378		}
379
380		if (SIGISMEMBER(p->p_sigacts->ps_sigignore, sig) ||
381		    SIGISMEMBER(td->td_sigmask, sig)) {
382			/* Only allow them in write()/ioctl(). */
383			PROC_UNLOCK(p);
384			return (sig == SIGTTOU ? 0 : EIO);
385		}
386
387		pg = p->p_pgrp;
388		if (p->p_flag & P_PPWAIT || pg->pg_jobc == 0) {
389			/* Don't allow the action to happen. */
390			PROC_UNLOCK(p);
391			return (EIO);
392		}
393		PROC_UNLOCK(p);
394
395		/*
396		 * Send the signal and sleep until we're the new
397		 * foreground process group.
398		 */
399		PGRP_LOCK(pg);
400		pgsignal(pg, sig, 1);
401		PGRP_UNLOCK(pg);
402
403		error = tty_wait(tp, &tp->t_bgwait);
404		if (error)
405			return (error);
406	}
407}
408
409static int
410ttydev_read(struct cdev *dev, struct uio *uio, int ioflag)
411{
412	struct tty *tp = dev->si_drv1;
413	int error;
414
415	error = ttydev_enter(tp);
416	if (error)
417		goto done;
418
419	error = tty_wait_background(tp, curthread, SIGTTIN);
420	if (error) {
421		tty_unlock(tp);
422		goto done;
423	}
424
425	error = ttydisc_read(tp, uio, ioflag);
426	tty_unlock(tp);
427
428	/*
429	 * The read() call should not throw an error when the device is
430	 * being destroyed. Silently convert it to an EOF.
431	 */
432done:	if (error == ENXIO)
433		error = 0;
434	return (error);
435}
436
437static int
438ttydev_write(struct cdev *dev, struct uio *uio, int ioflag)
439{
440	struct tty *tp = dev->si_drv1;
441	int error;
442
443	error = ttydev_enter(tp);
444	if (error)
445		return (error);
446
447	if (tp->t_termios.c_lflag & TOSTOP) {
448		error = tty_wait_background(tp, curthread, SIGTTOU);
449		if (error)
450			goto done;
451	}
452
453	if (ioflag & IO_NDELAY && tp->t_flags & TF_BUSY_OUT) {
454		/* Allow non-blocking writes to bypass serialization. */
455		error = ttydisc_write(tp, uio, ioflag);
456	} else {
457		/* Serialize write() calls. */
458		while (tp->t_flags & TF_BUSY_OUT) {
459			error = tty_wait(tp, &tp->t_outserwait);
460			if (error)
461				goto done;
462		}
463
464 		tp->t_flags |= TF_BUSY_OUT;
465		error = ttydisc_write(tp, uio, ioflag);
466 		tp->t_flags &= ~TF_BUSY_OUT;
467		cv_signal(&tp->t_outserwait);
468	}
469
470done:	tty_unlock(tp);
471	return (error);
472}
473
474static int
475ttydev_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int fflag,
476    struct thread *td)
477{
478	struct tty *tp = dev->si_drv1;
479	int error;
480
481	error = ttydev_enter(tp);
482	if (error)
483		return (error);
484
485	switch (cmd) {
486	case TIOCCBRK:
487	case TIOCCONS:
488	case TIOCDRAIN:
489	case TIOCEXCL:
490	case TIOCFLUSH:
491	case TIOCNXCL:
492	case TIOCSBRK:
493	case TIOCSCTTY:
494	case TIOCSETA:
495	case TIOCSETAF:
496	case TIOCSETAW:
497	case TIOCSPGRP:
498	case TIOCSTART:
499	case TIOCSTAT:
500	case TIOCSTOP:
501	case TIOCSWINSZ:
502#if 0
503	case TIOCSDRAINWAIT:
504	case TIOCSETD:
505	case TIOCSTI:
506#endif
507#ifdef COMPAT_43TTY
508	case  TIOCLBIC:
509	case  TIOCLBIS:
510	case  TIOCLSET:
511	case  TIOCSETC:
512	case OTIOCSETD:
513	case  TIOCSETN:
514	case  TIOCSETP:
515	case  TIOCSLTC:
516#endif /* COMPAT_43TTY */
517		/*
518		 * If the ioctl() causes the TTY to be modified, let it
519		 * wait in the background.
520		 */
521		error = tty_wait_background(tp, curthread, SIGTTOU);
522		if (error)
523			goto done;
524	}
525
526	error = tty_ioctl(tp, cmd, data, td);
527done:	tty_unlock(tp);
528
529	return (error);
530}
531
532static int
533ttydev_poll(struct cdev *dev, int events, struct thread *td)
534{
535	struct tty *tp = dev->si_drv1;
536	int error, revents = 0;
537
538	error = ttydev_enter(tp);
539	if (error) {
540		/* Don't return the error here, but the event mask. */
541		return (events &
542		    (POLLHUP|POLLIN|POLLRDNORM|POLLOUT|POLLWRNORM));
543	}
544
545	if (events & (POLLIN|POLLRDNORM)) {
546		/* See if we can read something. */
547		if (ttydisc_read_poll(tp) > 0)
548			revents |= events & (POLLIN|POLLRDNORM);
549	}
550	if (events & (POLLOUT|POLLWRNORM)) {
551		/* See if we can write something. */
552		if (ttydisc_write_poll(tp) > 0)
553			revents |= events & (POLLOUT|POLLWRNORM);
554	}
555	if (tp->t_flags & TF_ZOMBIE)
556		/* Hangup flag on zombie state. */
557		revents |= events & POLLHUP;
558
559	if (revents == 0) {
560		if (events & (POLLIN|POLLRDNORM))
561			selrecord(td, &tp->t_inpoll);
562		if (events & (POLLOUT|POLLWRNORM))
563			selrecord(td, &tp->t_outpoll);
564	}
565
566	tty_unlock(tp);
567
568	return (revents);
569}
570
571static int
572ttydev_mmap(struct cdev *dev, vm_offset_t offset, vm_paddr_t *paddr, int nprot)
573{
574	struct tty *tp = dev->si_drv1;
575	int error;
576
577	/* Handle mmap() through the driver. */
578
579	error = ttydev_enter(tp);
580	if (error)
581		return (-1);
582	error = ttydevsw_mmap(tp, offset, paddr, nprot);
583	tty_unlock(tp);
584
585	return (error);
586}
587
588/*
589 * kqueue support.
590 */
591
592static void
593tty_kqops_read_detach(struct knote *kn)
594{
595	struct tty *tp = kn->kn_hook;
596
597	knlist_remove(&tp->t_inpoll.si_note, kn, 0);
598}
599
600static int
601tty_kqops_read_event(struct knote *kn, long hint)
602{
603	struct tty *tp = kn->kn_hook;
604
605	tty_lock_assert(tp, MA_OWNED);
606
607	if (tty_gone(tp) || tp->t_flags & TF_ZOMBIE) {
608		kn->kn_flags |= EV_EOF;
609		return (1);
610	} else {
611		kn->kn_data = ttydisc_read_poll(tp);
612		return (kn->kn_data > 0);
613	}
614}
615
616static void
617tty_kqops_write_detach(struct knote *kn)
618{
619	struct tty *tp = kn->kn_hook;
620
621	knlist_remove(&tp->t_outpoll.si_note, kn, 0);
622}
623
624static int
625tty_kqops_write_event(struct knote *kn, long hint)
626{
627	struct tty *tp = kn->kn_hook;
628
629	tty_lock_assert(tp, MA_OWNED);
630
631	if (tty_gone(tp)) {
632		kn->kn_flags |= EV_EOF;
633		return (1);
634	} else {
635		kn->kn_data = ttydisc_write_poll(tp);
636		return (kn->kn_data > 0);
637	}
638}
639
640static struct filterops tty_kqops_read =
641    { 1, NULL, tty_kqops_read_detach, tty_kqops_read_event };
642static struct filterops tty_kqops_write =
643    { 1, NULL, tty_kqops_write_detach, tty_kqops_write_event };
644
645static int
646ttydev_kqfilter(struct cdev *dev, struct knote *kn)
647{
648	struct tty *tp = dev->si_drv1;
649	int error;
650
651	error = ttydev_enter(tp);
652	if (error)
653		return (error);
654
655	switch (kn->kn_filter) {
656	case EVFILT_READ:
657		kn->kn_hook = tp;
658		kn->kn_fop = &tty_kqops_read;
659		knlist_add(&tp->t_inpoll.si_note, kn, 1);
660		break;
661	case EVFILT_WRITE:
662		kn->kn_hook = tp;
663		kn->kn_fop = &tty_kqops_write;
664		knlist_add(&tp->t_outpoll.si_note, kn, 1);
665		break;
666	default:
667		error = EINVAL;
668		break;
669	}
670
671	tty_unlock(tp);
672	return (error);
673}
674
675static struct cdevsw ttydev_cdevsw = {
676	.d_version	= D_VERSION,
677	.d_open		= ttydev_open,
678	.d_close	= ttydev_close,
679	.d_read		= ttydev_read,
680	.d_write	= ttydev_write,
681	.d_ioctl	= ttydev_ioctl,
682	.d_kqfilter	= ttydev_kqfilter,
683	.d_poll		= ttydev_poll,
684	.d_mmap		= ttydev_mmap,
685	.d_name		= "ttydev",
686	.d_flags	= D_TTY,
687};
688
689/*
690 * Init/lock-state devices
691 */
692
693static int
694ttyil_open(struct cdev *dev, int oflags, int devtype, struct thread *td)
695{
696	struct tty *tp = dev->si_drv1;
697	int error = 0;
698
699	tty_lock(tp);
700	if (tty_gone(tp))
701		error = ENODEV;
702	tty_unlock(tp);
703
704	return (error);
705}
706
707static int
708ttyil_close(struct cdev *dev, int flag, int mode, struct thread *td)
709{
710	return (0);
711}
712
713static int
714ttyil_rdwr(struct cdev *dev, struct uio *uio, int ioflag)
715{
716	return (ENODEV);
717}
718
719static int
720ttyil_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int fflag,
721    struct thread *td)
722{
723	struct tty *tp = dev->si_drv1;
724	int error = 0;
725
726	tty_lock(tp);
727	if (tty_gone(tp)) {
728		error = ENODEV;
729		goto done;
730	}
731
732	switch (cmd) {
733	case TIOCGETA:
734		/* Obtain terminal flags through tcgetattr(). */
735		*(struct termios*)data = *(struct termios*)dev->si_drv2;
736		break;
737	case TIOCSETA:
738		/* Set terminal flags through tcsetattr(). */
739		error = priv_check(td, PRIV_TTY_SETA);
740		if (error)
741			break;
742		*(struct termios*)dev->si_drv2 = *(struct termios*)data;
743		break;
744	case TIOCGETD:
745		*(int *)data = TTYDISC;
746		break;
747	case TIOCGWINSZ:
748		bzero(data, sizeof(struct winsize));
749		break;
750	default:
751		error = ENOTTY;
752	}
753
754done:	tty_unlock(tp);
755	return (error);
756}
757
758static struct cdevsw ttyil_cdevsw = {
759	.d_version	= D_VERSION,
760	.d_open		= ttyil_open,
761	.d_close	= ttyil_close,
762	.d_read		= ttyil_rdwr,
763	.d_write	= ttyil_rdwr,
764	.d_ioctl	= ttyil_ioctl,
765	.d_name		= "ttyil",
766	.d_flags	= D_TTY,
767};
768
769static void
770tty_init_termios(struct tty *tp)
771{
772	struct termios *t = &tp->t_termios_init_in;
773
774	t->c_cflag = TTYDEF_CFLAG;
775	t->c_iflag = TTYDEF_IFLAG;
776	t->c_lflag = TTYDEF_LFLAG;
777	t->c_oflag = TTYDEF_OFLAG;
778	t->c_ispeed = TTYDEF_SPEED;
779	t->c_ospeed = TTYDEF_SPEED;
780	memcpy(&t->c_cc, ttydefchars, sizeof ttydefchars);
781
782	tp->t_termios_init_out = *t;
783}
784
785void
786tty_init_console(struct tty *tp, speed_t s)
787{
788	struct termios *ti = &tp->t_termios_init_in;
789	struct termios *to = &tp->t_termios_init_out;
790
791	if (s != 0) {
792		ti->c_ispeed = ti->c_ospeed = s;
793		to->c_ispeed = to->c_ospeed = s;
794	}
795
796	ti->c_cflag |= CLOCAL;
797	to->c_cflag |= CLOCAL;
798}
799
800/*
801 * Standard device routine implementations, mostly meant for
802 * pseudo-terminal device drivers. When a driver creates a new terminal
803 * device class, missing routines are patched.
804 */
805
806static int
807ttydevsw_defopen(struct tty *tp)
808{
809
810	return (0);
811}
812
813static void
814ttydevsw_defclose(struct tty *tp)
815{
816}
817
818static void
819ttydevsw_defoutwakeup(struct tty *tp)
820{
821
822	panic("Terminal device has output, while not implemented");
823}
824
825static void
826ttydevsw_definwakeup(struct tty *tp)
827{
828}
829
830static int
831ttydevsw_defioctl(struct tty *tp, u_long cmd, caddr_t data, struct thread *td)
832{
833
834	return (ENOIOCTL);
835}
836
837static int
838ttydevsw_defparam(struct tty *tp, struct termios *t)
839{
840
841	/* Use a fake baud rate, we're not a real device. */
842	t->c_ispeed = t->c_ospeed = TTYDEF_SPEED;
843
844	return (0);
845}
846
847static int
848ttydevsw_defmodem(struct tty *tp, int sigon, int sigoff)
849{
850
851	/* Simulate a carrier to make the TTY layer happy. */
852	return (SER_DCD);
853}
854
855static int
856ttydevsw_defmmap(struct tty *tp, vm_offset_t offset, vm_paddr_t *paddr,
857    int nprot)
858{
859
860	return (-1);
861}
862
863static void
864ttydevsw_defpktnotify(struct tty *tp, char event)
865{
866}
867
868static void
869ttydevsw_deffree(void *softc)
870{
871
872	panic("Terminal device freed without a free-handler");
873}
874
875/*
876 * TTY allocation and deallocation. TTY devices can be deallocated when
877 * the driver doesn't use it anymore, when the TTY isn't a session's
878 * controlling TTY and when the device node isn't opened through devfs.
879 */
880
881struct tty *
882tty_alloc(struct ttydevsw *tsw, void *sc)
883{
884
885	return (tty_alloc_mutex(tsw, sc, NULL));
886}
887
888struct tty *
889tty_alloc_mutex(struct ttydevsw *tsw, void *sc, struct mtx *mutex)
890{
891	struct tty *tp;
892
893	/* Make sure the driver defines all routines. */
894#define PATCH_FUNC(x) do {				\
895	if (tsw->tsw_ ## x == NULL)			\
896		tsw->tsw_ ## x = ttydevsw_def ## x;	\
897} while (0)
898	PATCH_FUNC(open);
899	PATCH_FUNC(close);
900	PATCH_FUNC(outwakeup);
901	PATCH_FUNC(inwakeup);
902	PATCH_FUNC(ioctl);
903	PATCH_FUNC(param);
904	PATCH_FUNC(modem);
905	PATCH_FUNC(mmap);
906	PATCH_FUNC(pktnotify);
907	PATCH_FUNC(free);
908#undef PATCH_FUNC
909
910	tp = malloc(sizeof(struct tty), M_TTY, M_WAITOK|M_ZERO);
911	tp->t_devsw = tsw;
912	tp->t_devswsoftc = sc;
913	tp->t_flags = tsw->tsw_flags;
914
915	tty_init_termios(tp);
916
917	cv_init(&tp->t_inwait, "ttyin");
918	cv_init(&tp->t_outwait, "ttyout");
919	cv_init(&tp->t_outserwait, "ttyosr");
920	cv_init(&tp->t_bgwait, "ttybg");
921	cv_init(&tp->t_dcdwait, "ttydcd");
922
923	/* Allow drivers to use a custom mutex to lock the TTY. */
924	if (mutex != NULL) {
925		tp->t_mtx = mutex;
926	} else {
927		tp->t_mtx = &tp->t_mtxobj;
928		mtx_init(&tp->t_mtxobj, "ttymtx", NULL, MTX_DEF);
929	}
930
931	knlist_init_mtx(&tp->t_inpoll.si_note, tp->t_mtx);
932	knlist_init_mtx(&tp->t_outpoll.si_note, tp->t_mtx);
933
934	sx_xlock(&tty_list_sx);
935	TAILQ_INSERT_TAIL(&tty_list, tp, t_list);
936	tty_list_count++;
937	sx_xunlock(&tty_list_sx);
938
939	return (tp);
940}
941
942static void
943tty_dealloc(void *arg)
944{
945	struct tty *tp = arg;
946
947	sx_xlock(&tty_list_sx);
948	TAILQ_REMOVE(&tty_list, tp, t_list);
949	tty_list_count--;
950	sx_xunlock(&tty_list_sx);
951
952	/* Make sure we haven't leaked buffers. */
953	MPASS(ttyinq_getsize(&tp->t_inq) == 0);
954	MPASS(ttyoutq_getsize(&tp->t_outq) == 0);
955
956	knlist_destroy(&tp->t_inpoll.si_note);
957	knlist_destroy(&tp->t_outpoll.si_note);
958
959	cv_destroy(&tp->t_inwait);
960	cv_destroy(&tp->t_outwait);
961	cv_destroy(&tp->t_bgwait);
962	cv_destroy(&tp->t_dcdwait);
963	cv_destroy(&tp->t_outserwait);
964
965	if (tp->t_mtx == &tp->t_mtxobj)
966		mtx_destroy(&tp->t_mtxobj);
967	ttydevsw_free(tp);
968	free(tp, M_TTY);
969}
970
971static void
972tty_rel_free(struct tty *tp)
973{
974	struct cdev *dev;
975
976	tty_lock_assert(tp, MA_OWNED);
977
978#define	TF_ACTIVITY	(TF_GONE|TF_OPENED|TF_HOOK|TF_OPENCLOSE)
979	if (tp->t_sessioncnt != 0 || (tp->t_flags & TF_ACTIVITY) != TF_GONE) {
980		/* TTY is still in use. */
981		tty_unlock(tp);
982		return;
983	}
984
985	/* TTY can be deallocated. */
986	dev = tp->t_dev;
987	tp->t_dev = NULL;
988	tty_unlock(tp);
989
990	destroy_dev_sched_cb(dev, tty_dealloc, tp);
991}
992
993void
994tty_rel_pgrp(struct tty *tp, struct pgrp *pg)
995{
996	MPASS(tp->t_sessioncnt > 0);
997	tty_lock_assert(tp, MA_OWNED);
998
999	if (tp->t_pgrp == pg)
1000		tp->t_pgrp = NULL;
1001
1002	tty_unlock(tp);
1003}
1004
1005void
1006tty_rel_sess(struct tty *tp, struct session *sess)
1007{
1008	MPASS(tp->t_sessioncnt > 0);
1009
1010	/* Current session has left. */
1011	if (tp->t_session == sess) {
1012		tp->t_session = NULL;
1013		MPASS(tp->t_pgrp == NULL);
1014	}
1015	tp->t_sessioncnt--;
1016	tty_rel_free(tp);
1017}
1018
1019void
1020tty_rel_gone(struct tty *tp)
1021{
1022	MPASS(!tty_gone(tp));
1023
1024	/* Simulate carrier removal. */
1025	ttydisc_modem(tp, 0);
1026
1027	/* Wake up all blocked threads. */
1028	tty_wakeup(tp, FREAD|FWRITE);
1029	cv_broadcast(&tp->t_bgwait);
1030	cv_broadcast(&tp->t_dcdwait);
1031
1032	tp->t_flags |= TF_GONE;
1033	tty_rel_free(tp);
1034}
1035
1036/*
1037 * Exposing information about current TTY's through sysctl
1038 */
1039
1040static void
1041tty_to_xtty(struct tty *tp, struct xtty *xt)
1042{
1043	tty_lock_assert(tp, MA_OWNED);
1044
1045	xt->xt_size = sizeof(struct xtty);
1046	xt->xt_insize = ttyinq_getsize(&tp->t_inq);
1047	xt->xt_incc = ttyinq_bytescanonicalized(&tp->t_inq);
1048	xt->xt_inlc = ttyinq_bytesline(&tp->t_inq);
1049	xt->xt_inlow = tp->t_inlow;
1050	xt->xt_outsize = ttyoutq_getsize(&tp->t_outq);
1051	xt->xt_outcc = ttyoutq_bytesused(&tp->t_outq);
1052	xt->xt_outlow = tp->t_outlow;
1053	xt->xt_column = tp->t_column;
1054	xt->xt_pgid = tp->t_pgrp ? tp->t_pgrp->pg_id : 0;
1055	xt->xt_sid = tp->t_session ? tp->t_session->s_sid : 0;
1056	xt->xt_flags = tp->t_flags;
1057	xt->xt_dev = tp->t_dev ? dev2udev(tp->t_dev) : NODEV;
1058}
1059
1060static int
1061sysctl_kern_ttys(SYSCTL_HANDLER_ARGS)
1062{
1063	unsigned long lsize;
1064	struct xtty *xtlist, *xt;
1065	struct tty *tp;
1066	int error;
1067
1068	sx_slock(&tty_list_sx);
1069	lsize = tty_list_count * sizeof(struct xtty);
1070	if (lsize == 0) {
1071		sx_sunlock(&tty_list_sx);
1072		return (0);
1073	}
1074
1075	xtlist = xt = malloc(lsize, M_TTY, M_WAITOK);
1076
1077	TAILQ_FOREACH(tp, &tty_list, t_list) {
1078		tty_lock(tp);
1079		tty_to_xtty(tp, xt);
1080		tty_unlock(tp);
1081		xt++;
1082	}
1083	sx_sunlock(&tty_list_sx);
1084
1085	error = SYSCTL_OUT(req, xtlist, lsize);
1086	free(xtlist, M_TTY);
1087	return (error);
1088}
1089
1090SYSCTL_PROC(_kern, OID_AUTO, ttys, CTLTYPE_OPAQUE|CTLFLAG_RD|CTLFLAG_MPSAFE,
1091	0, 0, sysctl_kern_ttys, "S,xtty", "List of TTYs");
1092
1093/*
1094 * Device node creation. Device has been set up, now we can expose it to
1095 * the user.
1096 */
1097
1098void
1099tty_makedev(struct tty *tp, struct ucred *cred, const char *fmt, ...)
1100{
1101	va_list ap;
1102	struct cdev *dev;
1103	const char *prefix = "tty";
1104	char name[SPECNAMELEN - 3]; /* for "tty" and "cua". */
1105	uid_t uid;
1106	gid_t gid;
1107	mode_t mode;
1108
1109	/* Remove "tty" prefix from devices like PTY's. */
1110	if (tp->t_flags & TF_NOPREFIX)
1111		prefix = "";
1112
1113	va_start(ap, fmt);
1114	vsnrprintf(name, sizeof name, 32, fmt, ap);
1115	va_end(ap);
1116
1117	if (cred == NULL) {
1118		/* System device. */
1119		uid = UID_ROOT;
1120		gid = GID_WHEEL;
1121		mode = S_IRUSR|S_IWUSR;
1122	} else {
1123		/* User device. */
1124		uid = cred->cr_ruid;
1125		gid = GID_TTY;
1126		mode = S_IRUSR|S_IWUSR|S_IWGRP;
1127	}
1128
1129	/* Master call-in device. */
1130	dev = make_dev_cred(&ttydev_cdevsw, 0, cred,
1131	    uid, gid, mode, "%s%s", prefix, name);
1132	dev->si_drv1 = tp;
1133	tp->t_dev = dev;
1134
1135	/* Slave call-in devices. */
1136	if (tp->t_flags & TF_INITLOCK) {
1137		dev = make_dev_cred(&ttyil_cdevsw, 0, cred,
1138		    uid, gid, mode, "%s%s.init", prefix, name);
1139		dev_depends(tp->t_dev, dev);
1140		dev->si_drv1 = tp;
1141		dev->si_drv2 = &tp->t_termios_init_in;
1142
1143		dev = make_dev_cred(&ttyil_cdevsw, 0, cred,
1144		    uid, gid, mode, "%s%s.lock", prefix, name);
1145		dev_depends(tp->t_dev, dev);
1146		dev->si_drv1 = tp;
1147		dev->si_drv2 = &tp->t_termios_lock_in;
1148	}
1149
1150	/* Call-out devices. */
1151	if (tp->t_flags & TF_CALLOUT) {
1152		dev = make_dev_cred(&ttydev_cdevsw, 0, cred,
1153		    UID_UUCP, GID_DIALER, 0660, "cua%s", name);
1154		dev_depends(tp->t_dev, dev);
1155		dev->si_drv1 = tp;
1156
1157		/* Slave call-out devices. */
1158		if (tp->t_flags & TF_INITLOCK) {
1159			dev = make_dev_cred(&ttyil_cdevsw, 0, cred,
1160			    UID_UUCP, GID_DIALER, 0660, "cua%s.init", name);
1161			dev_depends(tp->t_dev, dev);
1162			dev->si_drv1 = tp;
1163			dev->si_drv2 = &tp->t_termios_init_out;
1164
1165			dev = make_dev_cred(&ttyil_cdevsw, 0, cred,
1166			    UID_UUCP, GID_DIALER, 0660, "cua%s.lock", name);
1167			dev_depends(tp->t_dev, dev);
1168			dev->si_drv1 = tp;
1169			dev->si_drv2 = &tp->t_termios_lock_out;
1170		}
1171	}
1172}
1173
1174/*
1175 * Signalling processes.
1176 */
1177
1178void
1179tty_signal_sessleader(struct tty *tp, int sig)
1180{
1181	struct proc *p;
1182
1183	tty_lock_assert(tp, MA_OWNED);
1184	MPASS(sig >= 1 && sig < NSIG);
1185
1186	/* Make signals start output again. */
1187	tp->t_flags &= ~TF_STOPPED;
1188
1189	if (tp->t_session != NULL && tp->t_session->s_leader != NULL) {
1190		p = tp->t_session->s_leader;
1191		PROC_LOCK(p);
1192		psignal(p, sig);
1193		PROC_UNLOCK(p);
1194	}
1195}
1196
1197void
1198tty_signal_pgrp(struct tty *tp, int sig)
1199{
1200	tty_lock_assert(tp, MA_OWNED);
1201	MPASS(sig >= 1 && sig < NSIG);
1202
1203	/* Make signals start output again. */
1204	tp->t_flags &= ~TF_STOPPED;
1205
1206	if (sig == SIGINFO && !(tp->t_termios.c_lflag & NOKERNINFO))
1207		tty_info(tp);
1208	if (tp->t_pgrp != NULL) {
1209		PGRP_LOCK(tp->t_pgrp);
1210		pgsignal(tp->t_pgrp, sig, 1);
1211		PGRP_UNLOCK(tp->t_pgrp);
1212	}
1213}
1214
1215void
1216tty_wakeup(struct tty *tp, int flags)
1217{
1218	if (tp->t_flags & TF_ASYNC && tp->t_sigio != NULL)
1219		pgsigio(&tp->t_sigio, SIGIO, (tp->t_session != NULL));
1220
1221	if (flags & FWRITE) {
1222		cv_broadcast(&tp->t_outwait);
1223		selwakeup(&tp->t_outpoll);
1224		KNOTE_LOCKED(&tp->t_outpoll.si_note, 0);
1225	}
1226	if (flags & FREAD) {
1227		cv_broadcast(&tp->t_inwait);
1228		selwakeup(&tp->t_inpoll);
1229		KNOTE_LOCKED(&tp->t_inpoll.si_note, 0);
1230	}
1231}
1232
1233int
1234tty_wait(struct tty *tp, struct cv *cv)
1235{
1236	int error;
1237	int revokecnt = tp->t_revokecnt;
1238
1239	tty_lock_assert(tp, MA_OWNED|MA_NOTRECURSED);
1240	MPASS(!tty_gone(tp));
1241
1242	error = cv_wait_sig(cv, tp->t_mtx);
1243
1244	/* Restart the system call when we may have been revoked. */
1245	if (tp->t_revokecnt != revokecnt)
1246		return (ERESTART);
1247
1248	/* Bail out when the device slipped away. */
1249	if (tty_gone(tp))
1250		return (ENXIO);
1251
1252	return (error);
1253}
1254
1255int
1256tty_timedwait(struct tty *tp, struct cv *cv, int hz)
1257{
1258	int error;
1259	int revokecnt = tp->t_revokecnt;
1260
1261	tty_lock_assert(tp, MA_OWNED|MA_NOTRECURSED);
1262	MPASS(!tty_gone(tp));
1263
1264	error = cv_timedwait_sig(cv, tp->t_mtx, hz);
1265
1266	/* Restart the system call when we may have been revoked. */
1267	if (tp->t_revokecnt != revokecnt)
1268		return (ERESTART);
1269
1270	/* Bail out when the device slipped away. */
1271	if (tty_gone(tp))
1272		return (ENXIO);
1273
1274	return (error);
1275}
1276
1277void
1278tty_flush(struct tty *tp, int flags)
1279{
1280	if (flags & FWRITE) {
1281		tp->t_flags &= ~TF_HIWAT_OUT;
1282		ttyoutq_flush(&tp->t_outq);
1283		tty_wakeup(tp, FWRITE);
1284		ttydevsw_pktnotify(tp, TIOCPKT_FLUSHWRITE);
1285	}
1286	if (flags & FREAD) {
1287		tty_hiwat_in_unblock(tp);
1288		ttyinq_flush(&tp->t_inq);
1289		ttydevsw_inwakeup(tp);
1290		ttydevsw_pktnotify(tp, TIOCPKT_FLUSHREAD);
1291	}
1292}
1293
1294static int
1295tty_generic_ioctl(struct tty *tp, u_long cmd, void *data, struct thread *td)
1296{
1297	int error;
1298
1299	switch (cmd) {
1300	/*
1301	 * Modem commands.
1302	 * The SER_* and TIOCM_* flags are the same, but one bit
1303	 * shifted. I don't know why.
1304	 */
1305	case TIOCSDTR:
1306		ttydevsw_modem(tp, SER_DTR, 0);
1307		return (0);
1308	case TIOCCDTR:
1309		ttydevsw_modem(tp, 0, SER_DTR);
1310		return (0);
1311	case TIOCMSET: {
1312		int bits = *(int *)data;
1313		ttydevsw_modem(tp,
1314		    (bits & (TIOCM_DTR | TIOCM_RTS)) >> 1,
1315		    ((~bits) & (TIOCM_DTR | TIOCM_RTS)) >> 1);
1316		return (0);
1317	}
1318	case TIOCMBIS: {
1319		int bits = *(int *)data;
1320		ttydevsw_modem(tp, (bits & (TIOCM_DTR | TIOCM_RTS)) >> 1, 0);
1321		return (0);
1322	}
1323	case TIOCMBIC: {
1324		int bits = *(int *)data;
1325		ttydevsw_modem(tp, 0, (bits & (TIOCM_DTR | TIOCM_RTS)) >> 1);
1326		return (0);
1327	}
1328	case TIOCMGET:
1329		*(int *)data = TIOCM_LE + (ttydevsw_modem(tp, 0, 0) << 1);
1330		return (0);
1331
1332	case FIOASYNC:
1333		if (*(int *)data)
1334			tp->t_flags |= TF_ASYNC;
1335		else
1336			tp->t_flags &= ~TF_ASYNC;
1337		return (0);
1338	case FIONBIO:
1339		/* This device supports non-blocking operation. */
1340		return (0);
1341	case FIONREAD:
1342		*(int *)data = ttyinq_bytescanonicalized(&tp->t_inq);
1343		return (0);
1344	case FIOSETOWN:
1345		if (tp->t_session != NULL && !tty_is_ctty(tp, td->td_proc))
1346			/* Not allowed to set ownership. */
1347			return (ENOTTY);
1348
1349		/* Temporarily unlock the TTY to set ownership. */
1350		tty_unlock(tp);
1351		error = fsetown(*(int *)data, &tp->t_sigio);
1352		tty_lock(tp);
1353		return (error);
1354	case FIOGETOWN:
1355		if (tp->t_session != NULL && !tty_is_ctty(tp, td->td_proc))
1356			/* Not allowed to set ownership. */
1357			return (ENOTTY);
1358
1359		/* Get ownership. */
1360		*(int *)data = fgetown(&tp->t_sigio);
1361		return (0);
1362	case TIOCGETA:
1363		/* Obtain terminal flags through tcgetattr(). */
1364		*(struct termios*)data = tp->t_termios;
1365		return (0);
1366	case TIOCSETA:
1367	case TIOCSETAW:
1368	case TIOCSETAF: {
1369		struct termios *t = data;
1370
1371		/*
1372		 * Who makes up these funny rules? According to POSIX,
1373		 * input baud rate is set equal to the output baud rate
1374		 * when zero.
1375		 */
1376		if (t->c_ispeed == 0)
1377			t->c_ispeed = t->c_ospeed;
1378
1379		/* Discard any unsupported bits. */
1380		t->c_iflag &= TTYSUP_IFLAG;
1381		t->c_oflag &= TTYSUP_OFLAG;
1382		t->c_lflag &= TTYSUP_LFLAG;
1383		t->c_cflag &= TTYSUP_CFLAG;
1384
1385		/* Set terminal flags through tcsetattr(). */
1386		if (cmd == TIOCSETAW || cmd == TIOCSETAF) {
1387			error = tty_drain(tp);
1388			if (error)
1389				return (error);
1390			if (cmd == TIOCSETAF)
1391				tty_flush(tp, FREAD);
1392		}
1393
1394		/*
1395		 * Only call param() when the flags really change.
1396		 */
1397		if ((t->c_cflag & CIGNORE) == 0 &&
1398		    (tp->t_termios.c_cflag != t->c_cflag ||
1399		    tp->t_termios.c_ispeed != t->c_ispeed ||
1400		    tp->t_termios.c_ospeed != t->c_ospeed)) {
1401			error = ttydevsw_param(tp, t);
1402			if (error)
1403				return (error);
1404
1405			/* XXX: CLOCAL? */
1406
1407			tp->t_termios.c_cflag = t->c_cflag & ~CIGNORE;
1408			tp->t_termios.c_ispeed = t->c_ispeed;
1409			tp->t_termios.c_ospeed = t->c_ospeed;
1410
1411			/* Baud rate has changed - update watermarks. */
1412			tty_watermarks(tp);
1413		}
1414
1415		/* Copy new non-device driver parameters. */
1416		tp->t_termios.c_iflag = t->c_iflag;
1417		tp->t_termios.c_oflag = t->c_oflag;
1418		tp->t_termios.c_lflag = t->c_lflag;
1419		memcpy(&tp->t_termios.c_cc, t->c_cc, sizeof t->c_cc);
1420
1421		ttydisc_optimize(tp);
1422
1423		if ((t->c_lflag & ICANON) == 0) {
1424			/*
1425			 * When in non-canonical mode, wake up all
1426			 * readers. Canonicalize any partial input. VMIN
1427			 * and VTIME could also be adjusted.
1428			 */
1429			ttyinq_canonicalize(&tp->t_inq);
1430			tty_wakeup(tp, FREAD);
1431		}
1432
1433		/*
1434		 * For packet mode: notify the PTY consumer that VSTOP
1435		 * and VSTART may have been changed.
1436		 */
1437		if (tp->t_termios.c_iflag & IXON &&
1438		    tp->t_termios.c_cc[VSTOP] == CTRL('S') &&
1439		    tp->t_termios.c_cc[VSTART] == CTRL('Q'))
1440			ttydevsw_pktnotify(tp, TIOCPKT_DOSTOP);
1441		else
1442			ttydevsw_pktnotify(tp, TIOCPKT_NOSTOP);
1443		return (0);
1444	}
1445	case TIOCGETD:
1446		/* For compatibility - we only support TTYDISC. */
1447		*(int *)data = TTYDISC;
1448		return (0);
1449	case TIOCGPGRP:
1450		if (!tty_is_ctty(tp, td->td_proc))
1451			return (ENOTTY);
1452
1453		if (tp->t_pgrp != NULL)
1454			*(int *)data = tp->t_pgrp->pg_id;
1455		else
1456			*(int *)data = NO_PID;
1457		return (0);
1458	case TIOCGSID:
1459		if (!tty_is_ctty(tp, td->td_proc))
1460			return (ENOTTY);
1461
1462		MPASS(tp->t_session);
1463		*(int *)data = tp->t_session->s_sid;
1464		return (0);
1465	case TIOCSCTTY: {
1466		struct proc *p = td->td_proc;
1467
1468		/* XXX: This looks awful. */
1469		tty_unlock(tp);
1470		sx_xlock(&proctree_lock);
1471		tty_lock(tp);
1472
1473		if (!SESS_LEADER(p)) {
1474			/* Only the session leader may do this. */
1475			sx_xunlock(&proctree_lock);
1476			return (EPERM);
1477		}
1478
1479		if (tp->t_session != NULL && tp->t_session == p->p_session) {
1480			/* This is already our controlling TTY. */
1481			sx_xunlock(&proctree_lock);
1482			return (0);
1483		}
1484
1485		if (p->p_session->s_ttyp != NULL ||
1486		    (tp->t_session != NULL && tp->t_session->s_ttyvp != NULL &&
1487		    tp->t_session->s_ttyvp->v_type != VBAD)) {
1488			/*
1489			 * There is already a relation between a TTY and
1490			 * a session, or the caller is not the session
1491			 * leader.
1492			 *
1493			 * Allow the TTY to be stolen when the vnode is
1494			 * invalid, but the reference to the TTY is
1495			 * still active.  This allows immediate reuse of
1496			 * TTYs of which the session leader has been
1497			 * killed or the TTY revoked.
1498			 */
1499			sx_xunlock(&proctree_lock);
1500			return (EPERM);
1501		}
1502
1503		/* Connect the session to the TTY. */
1504		tp->t_session = p->p_session;
1505		tp->t_session->s_ttyp = tp;
1506		tp->t_sessioncnt++;
1507		sx_xunlock(&proctree_lock);
1508
1509		/* Assign foreground process group. */
1510		tp->t_pgrp = p->p_pgrp;
1511		PROC_LOCK(p);
1512		p->p_flag |= P_CONTROLT;
1513		PROC_UNLOCK(p);
1514
1515		return (0);
1516	}
1517	case TIOCSPGRP: {
1518		struct pgrp *pg;
1519
1520		/*
1521		 * XXX: Temporarily unlock the TTY to locate the process
1522		 * group. This code would be lot nicer if we would ever
1523		 * decompose proctree_lock.
1524		 */
1525		tty_unlock(tp);
1526		sx_slock(&proctree_lock);
1527		pg = pgfind(*(int *)data);
1528		if (pg != NULL)
1529			PGRP_UNLOCK(pg);
1530		if (pg == NULL || pg->pg_session != td->td_proc->p_session) {
1531			sx_sunlock(&proctree_lock);
1532			tty_lock(tp);
1533			return (EPERM);
1534		}
1535		tty_lock(tp);
1536
1537		/*
1538		 * Determine if this TTY is the controlling TTY after
1539		 * relocking the TTY.
1540		 */
1541		if (!tty_is_ctty(tp, td->td_proc)) {
1542			sx_sunlock(&proctree_lock);
1543			return (ENOTTY);
1544		}
1545		tp->t_pgrp = pg;
1546		sx_sunlock(&proctree_lock);
1547
1548		/* Wake up the background process groups. */
1549		cv_broadcast(&tp->t_bgwait);
1550		return (0);
1551	}
1552	case TIOCFLUSH: {
1553		int flags = *(int *)data;
1554
1555		if (flags == 0)
1556			flags = (FREAD|FWRITE);
1557		else
1558			flags &= (FREAD|FWRITE);
1559		tty_flush(tp, flags);
1560		return (0);
1561	}
1562	case TIOCDRAIN:
1563		/* Drain TTY output. */
1564		return tty_drain(tp);
1565	case TIOCCONS:
1566		/* Set terminal as console TTY. */
1567		if (*(int *)data) {
1568			error = priv_check(td, PRIV_TTY_CONSOLE);
1569			if (error)
1570				return (error);
1571
1572			/*
1573			 * XXX: constty should really need to be locked!
1574			 * XXX: allow disconnected constty's to be stolen!
1575			 */
1576
1577			if (constty == tp)
1578				return (0);
1579			if (constty != NULL)
1580				return (EBUSY);
1581
1582			tty_unlock(tp);
1583			constty_set(tp);
1584			tty_lock(tp);
1585		} else if (constty == tp) {
1586			constty_clear();
1587		}
1588		return (0);
1589	case TIOCGWINSZ:
1590		/* Obtain window size. */
1591		*(struct winsize*)data = tp->t_winsize;
1592		return (0);
1593	case TIOCSWINSZ:
1594		/* Set window size. */
1595		if (bcmp(&tp->t_winsize, data, sizeof(struct winsize)) == 0)
1596			return (0);
1597		tp->t_winsize = *(struct winsize*)data;
1598		tty_signal_pgrp(tp, SIGWINCH);
1599		return (0);
1600	case TIOCEXCL:
1601		tp->t_flags |= TF_EXCLUDE;
1602		return (0);
1603	case TIOCNXCL:
1604		tp->t_flags &= ~TF_EXCLUDE;
1605		return (0);
1606	case TIOCOUTQ:
1607		*(unsigned int *)data = ttyoutq_bytesused(&tp->t_outq);
1608		return (0);
1609	case TIOCSTOP:
1610		tp->t_flags |= TF_STOPPED;
1611		ttydevsw_pktnotify(tp, TIOCPKT_STOP);
1612		return (0);
1613	case TIOCSTART:
1614		tp->t_flags &= ~TF_STOPPED;
1615		ttydevsw_outwakeup(tp);
1616		ttydevsw_pktnotify(tp, TIOCPKT_START);
1617		return (0);
1618	case TIOCSTAT:
1619		tty_info(tp);
1620		return (0);
1621	}
1622
1623#ifdef COMPAT_43TTY
1624	return tty_ioctl_compat(tp, cmd, data, td);
1625#else /* !COMPAT_43TTY */
1626	return (ENOIOCTL);
1627#endif /* COMPAT_43TTY */
1628}
1629
1630int
1631tty_ioctl(struct tty *tp, u_long cmd, void *data, struct thread *td)
1632{
1633	int error;
1634
1635	tty_lock_assert(tp, MA_OWNED);
1636
1637	if (tty_gone(tp))
1638		return (ENXIO);
1639
1640	error = ttydevsw_ioctl(tp, cmd, data, td);
1641	if (error == ENOIOCTL)
1642		error = tty_generic_ioctl(tp, cmd, data, td);
1643
1644	return (error);
1645}
1646
1647dev_t
1648tty_udev(struct tty *tp)
1649{
1650	if (tp->t_dev)
1651		return dev2udev(tp->t_dev);
1652	else
1653		return NODEV;
1654}
1655
1656int
1657tty_checkoutq(struct tty *tp)
1658{
1659
1660	/* 256 bytes should be enough to print a log message. */
1661	return (ttyoutq_bytesleft(&tp->t_outq) >= 256);
1662}
1663
1664void
1665tty_hiwat_in_block(struct tty *tp)
1666{
1667
1668	if ((tp->t_flags & TF_HIWAT_IN) == 0 &&
1669	    tp->t_termios.c_iflag & IXOFF &&
1670	    tp->t_termios.c_cc[VSTOP] != _POSIX_VDISABLE) {
1671		/*
1672		 * Input flow control. Only enter the high watermark when we
1673		 * can successfully store the VSTOP character.
1674		 */
1675		if (ttyoutq_write_nofrag(&tp->t_outq,
1676		    &tp->t_termios.c_cc[VSTOP], 1) == 0)
1677			tp->t_flags |= TF_HIWAT_IN;
1678	} else {
1679		/* No input flow control. */
1680		tp->t_flags |= TF_HIWAT_IN;
1681	}
1682}
1683
1684void
1685tty_hiwat_in_unblock(struct tty *tp)
1686{
1687
1688	if (tp->t_flags & TF_HIWAT_IN &&
1689	    tp->t_termios.c_iflag & IXOFF &&
1690	    tp->t_termios.c_cc[VSTART] != _POSIX_VDISABLE) {
1691		/*
1692		 * Input flow control. Only leave the high watermark when we
1693		 * can successfully store the VSTART character.
1694		 */
1695		if (ttyoutq_write_nofrag(&tp->t_outq,
1696		    &tp->t_termios.c_cc[VSTART], 1) == 0)
1697			tp->t_flags &= ~TF_HIWAT_IN;
1698	} else {
1699		/* No input flow control. */
1700		tp->t_flags &= ~TF_HIWAT_IN;
1701	}
1702
1703	if (!tty_gone(tp))
1704		ttydevsw_inwakeup(tp);
1705}
1706
1707/*
1708 * TTY hooks interface.
1709 */
1710
1711static int
1712ttyhook_defrint(struct tty *tp, char c, int flags)
1713{
1714
1715	if (ttyhook_rint_bypass(tp, &c, 1) != 1)
1716		return (-1);
1717
1718	return (0);
1719}
1720
1721int
1722ttyhook_register(struct tty **rtp, struct proc *p, int fd,
1723    struct ttyhook *th, void *softc)
1724{
1725	struct tty *tp;
1726	struct file *fp;
1727	struct cdev *dev;
1728	struct cdevsw *cdp;
1729	struct filedesc *fdp;
1730	int error;
1731
1732	/* Validate the file descriptor. */
1733	if ((fdp = p->p_fd) == NULL)
1734		return (EBADF);
1735
1736	fp = fget_unlocked(fdp, fd);
1737	if (fp == NULL)
1738		return (EBADF);
1739	if (fp->f_ops == &badfileops) {
1740		error = EBADF;
1741		goto done1;
1742	}
1743
1744	/*
1745	 * Make sure the vnode is bound to a character device.
1746	 * Unlocked check for the vnode type is ok there, because we
1747	 * only shall prevent calling devvn_refthread on the file that
1748	 * never has been opened over a character device.
1749	 */
1750	if (fp->f_type != DTYPE_VNODE || fp->f_vnode->v_type != VCHR) {
1751		error = EINVAL;
1752		goto done1;
1753	}
1754
1755	/* Make sure it is a TTY. */
1756	cdp = devvn_refthread(fp->f_vnode, &dev);
1757	if (cdp == NULL) {
1758		error = ENXIO;
1759		goto done1;
1760	}
1761	if (dev != fp->f_data) {
1762		error = ENXIO;
1763		goto done2;
1764	}
1765	if (cdp != &ttydev_cdevsw) {
1766		error = ENOTTY;
1767		goto done2;
1768	}
1769	tp = dev->si_drv1;
1770
1771	/* Try to attach the hook to the TTY. */
1772	error = EBUSY;
1773	tty_lock(tp);
1774	MPASS((tp->t_hook == NULL) == ((tp->t_flags & TF_HOOK) == 0));
1775	if (tp->t_flags & TF_HOOK)
1776		goto done3;
1777
1778	tp->t_flags |= TF_HOOK;
1779	tp->t_hook = th;
1780	tp->t_hooksoftc = softc;
1781	*rtp = tp;
1782	error = 0;
1783
1784	/* Maybe we can switch into bypass mode now. */
1785	ttydisc_optimize(tp);
1786
1787	/* Silently convert rint() calls to rint_bypass() when possible. */
1788	if (!ttyhook_hashook(tp, rint) && ttyhook_hashook(tp, rint_bypass))
1789		th->th_rint = ttyhook_defrint;
1790
1791done3:	tty_unlock(tp);
1792done2:	dev_relthread(dev);
1793done1:	fdrop(fp, curthread);
1794	return (error);
1795}
1796
1797void
1798ttyhook_unregister(struct tty *tp)
1799{
1800
1801	tty_lock_assert(tp, MA_OWNED);
1802	MPASS(tp->t_flags & TF_HOOK);
1803
1804	/* Disconnect the hook. */
1805	tp->t_flags &= ~TF_HOOK;
1806	tp->t_hook = NULL;
1807
1808	/* Maybe we need to leave bypass mode. */
1809	ttydisc_optimize(tp);
1810
1811	/* Maybe deallocate the TTY as well. */
1812	tty_rel_free(tp);
1813}
1814
1815/*
1816 * /dev/console handling.
1817 */
1818
1819static int
1820ttyconsdev_open(struct cdev *dev, int oflags, int devtype, struct thread *td)
1821{
1822	struct tty *tp;
1823
1824	/* System has no console device. */
1825	if (dev_console_filename == NULL)
1826		return (ENXIO);
1827
1828	/* Look up corresponding TTY by device name. */
1829	sx_slock(&tty_list_sx);
1830	TAILQ_FOREACH(tp, &tty_list, t_list) {
1831		if (strcmp(dev_console_filename, tty_devname(tp)) == 0) {
1832			dev_console->si_drv1 = tp;
1833			break;
1834		}
1835	}
1836	sx_sunlock(&tty_list_sx);
1837
1838	/* System console has no TTY associated. */
1839	if (dev_console->si_drv1 == NULL)
1840		return (ENXIO);
1841
1842	return (ttydev_open(dev, oflags, devtype, td));
1843}
1844
1845static int
1846ttyconsdev_write(struct cdev *dev, struct uio *uio, int ioflag)
1847{
1848
1849	log_console(uio);
1850
1851	return (ttydev_write(dev, uio, ioflag));
1852}
1853
1854/*
1855 * /dev/console is a little different than normal TTY's.  When opened,
1856 * it determines which TTY to use.  When data gets written to it, it
1857 * will be logged in the kernel message buffer.
1858 */
1859static struct cdevsw ttyconsdev_cdevsw = {
1860	.d_version	= D_VERSION,
1861	.d_open		= ttyconsdev_open,
1862	.d_close	= ttydev_close,
1863	.d_read		= ttydev_read,
1864	.d_write	= ttyconsdev_write,
1865	.d_ioctl	= ttydev_ioctl,
1866	.d_kqfilter	= ttydev_kqfilter,
1867	.d_poll		= ttydev_poll,
1868	.d_mmap		= ttydev_mmap,
1869	.d_name		= "ttyconsdev",
1870	.d_flags	= D_TTY,
1871};
1872
1873static void
1874ttyconsdev_init(void *unused)
1875{
1876
1877	dev_console = make_dev(&ttyconsdev_cdevsw, 0, UID_ROOT, GID_WHEEL,
1878	    0600, "console");
1879}
1880
1881SYSINIT(tty, SI_SUB_DRIVERS, SI_ORDER_FIRST, ttyconsdev_init, NULL);
1882
1883void
1884ttyconsdev_select(const char *name)
1885{
1886
1887	dev_console_filename = name;
1888}
1889
1890/*
1891 * Debugging routines.
1892 */
1893
1894#include "opt_ddb.h"
1895#ifdef DDB
1896#include <ddb/ddb.h>
1897#include <ddb/db_sym.h>
1898
1899static struct {
1900	int flag;
1901	char val;
1902} ttystates[] = {
1903#if 0
1904	{ TF_NOPREFIX,		'N' },
1905#endif
1906	{ TF_INITLOCK,		'I' },
1907	{ TF_CALLOUT,		'C' },
1908
1909	/* Keep these together -> 'Oi' and 'Oo'. */
1910	{ TF_OPENED,		'O' },
1911	{ TF_OPENED_IN,		'i' },
1912	{ TF_OPENED_OUT,	'o' },
1913	{ TF_OPENED_CONS,	'c' },
1914
1915	{ TF_GONE,		'G' },
1916	{ TF_OPENCLOSE,		'B' },
1917	{ TF_ASYNC,		'Y' },
1918	{ TF_LITERAL,		'L' },
1919
1920	/* Keep these together -> 'Hi' and 'Ho'. */
1921	{ TF_HIWAT,		'H' },
1922	{ TF_HIWAT_IN,		'i' },
1923	{ TF_HIWAT_OUT,		'o' },
1924
1925	{ TF_STOPPED,		'S' },
1926	{ TF_EXCLUDE,		'X' },
1927	{ TF_BYPASS,		'l' },
1928	{ TF_ZOMBIE,		'Z' },
1929	{ TF_HOOK,		's' },
1930
1931	/* Keep these together -> 'bi' and 'bo'. */
1932	{ TF_BUSY,		'b' },
1933	{ TF_BUSY_IN,		'i' },
1934	{ TF_BUSY_OUT,		'o' },
1935
1936	{ 0,			'\0'},
1937};
1938
1939#define	TTY_FLAG_BITS \
1940	"\20\1NOPREFIX\2INITLOCK\3CALLOUT\4OPENED_IN\5OPENED_OUT\6GONE" \
1941	"\7OPENCLOSE\10ASYNC\11LITERAL\12HIWAT_IN\13HIWAT_OUT\14STOPPED" \
1942	"\15EXCLUDE\16BYPASS\17ZOMBIE\20HOOK"
1943
1944#define DB_PRINTSYM(name, addr) \
1945	db_printf("%s  " #name ": ", sep); \
1946	db_printsym((db_addr_t) addr, DB_STGY_ANY); \
1947	db_printf("\n");
1948
1949static void
1950_db_show_devsw(const char *sep, const struct ttydevsw *tsw)
1951{
1952	db_printf("%sdevsw: ", sep);
1953	db_printsym((db_addr_t)tsw, DB_STGY_ANY);
1954	db_printf(" (%p)\n", tsw);
1955	DB_PRINTSYM(open, tsw->tsw_open);
1956	DB_PRINTSYM(close, tsw->tsw_close);
1957	DB_PRINTSYM(outwakeup, tsw->tsw_outwakeup);
1958	DB_PRINTSYM(inwakeup, tsw->tsw_inwakeup);
1959	DB_PRINTSYM(ioctl, tsw->tsw_ioctl);
1960	DB_PRINTSYM(param, tsw->tsw_param);
1961	DB_PRINTSYM(modem, tsw->tsw_modem);
1962	DB_PRINTSYM(mmap, tsw->tsw_mmap);
1963	DB_PRINTSYM(pktnotify, tsw->tsw_pktnotify);
1964	DB_PRINTSYM(free, tsw->tsw_free);
1965}
1966static void
1967_db_show_hooks(const char *sep, const struct ttyhook *th)
1968{
1969	db_printf("%shook: ", sep);
1970	db_printsym((db_addr_t)th, DB_STGY_ANY);
1971	db_printf(" (%p)\n", th);
1972	if (th == NULL)
1973		return;
1974	DB_PRINTSYM(rint, th->th_rint);
1975	DB_PRINTSYM(rint_bypass, th->th_rint_bypass);
1976	DB_PRINTSYM(rint_done, th->th_rint_done);
1977	DB_PRINTSYM(rint_poll, th->th_rint_poll);
1978	DB_PRINTSYM(getc_inject, th->th_getc_inject);
1979	DB_PRINTSYM(getc_capture, th->th_getc_capture);
1980	DB_PRINTSYM(getc_poll, th->th_getc_poll);
1981	DB_PRINTSYM(close, th->th_close);
1982}
1983
1984static void
1985_db_show_termios(const char *name, const struct termios *t)
1986{
1987
1988	db_printf("%s: iflag 0x%x oflag 0x%x cflag 0x%x "
1989	    "lflag 0x%x ispeed %u ospeed %u\n", name,
1990	    t->c_iflag, t->c_oflag, t->c_cflag, t->c_lflag,
1991	    t->c_ispeed, t->c_ospeed);
1992}
1993
1994/* DDB command to show TTY statistics. */
1995DB_SHOW_COMMAND(tty, db_show_tty)
1996{
1997	struct tty *tp;
1998
1999	if (!have_addr) {
2000		db_printf("usage: show tty <addr>\n");
2001		return;
2002	}
2003	tp = (struct tty *)addr;
2004
2005	db_printf("0x%p: %s\n", tp, tty_devname(tp));
2006	db_printf("\tmtx: %p\n", tp->t_mtx);
2007	db_printf("\tflags: %b\n", tp->t_flags, TTY_FLAG_BITS);
2008	db_printf("\trevokecnt: %u\n", tp->t_revokecnt);
2009
2010	/* Buffering mechanisms. */
2011	db_printf("\tinq: %p begin %u linestart %u reprint %u end %u "
2012	    "nblocks %u quota %u\n", &tp->t_inq, tp->t_inq.ti_begin,
2013	    tp->t_inq.ti_linestart, tp->t_inq.ti_reprint, tp->t_inq.ti_end,
2014	    tp->t_inq.ti_nblocks, tp->t_inq.ti_quota);
2015	db_printf("\toutq: %p begin %u end %u nblocks %u quota %u\n",
2016	    &tp->t_outq, tp->t_outq.to_begin, tp->t_outq.to_end,
2017	    tp->t_outq.to_nblocks, tp->t_outq.to_quota);
2018	db_printf("\tinlow: %zu\n", tp->t_inlow);
2019	db_printf("\toutlow: %zu\n", tp->t_outlow);
2020	_db_show_termios("\ttermios", &tp->t_termios);
2021	db_printf("\twinsize: row %u col %u xpixel %u ypixel %u\n",
2022	    tp->t_winsize.ws_row, tp->t_winsize.ws_col,
2023	    tp->t_winsize.ws_xpixel, tp->t_winsize.ws_ypixel);
2024	db_printf("\tcolumn: %u\n", tp->t_column);
2025	db_printf("\twritepos: %u\n", tp->t_writepos);
2026	db_printf("\tcompatflags: 0x%x\n", tp->t_compatflags);
2027
2028	/* Init/lock-state devices. */
2029	_db_show_termios("\ttermios_init_in", &tp->t_termios_init_in);
2030	_db_show_termios("\ttermios_init_out", &tp->t_termios_init_out);
2031	_db_show_termios("\ttermios_lock_in", &tp->t_termios_lock_in);
2032	_db_show_termios("\ttermios_lock_out", &tp->t_termios_lock_out);
2033
2034	/* Hooks */
2035	_db_show_devsw("\t", tp->t_devsw);
2036	_db_show_hooks("\t", tp->t_hook);
2037
2038	/* Process info. */
2039	db_printf("\tpgrp: %p gid %d jobc %d\n", tp->t_pgrp,
2040	    tp->t_pgrp ? tp->t_pgrp->pg_id : 0,
2041	    tp->t_pgrp ? tp->t_pgrp->pg_jobc : 0);
2042	db_printf("\tsession: %p", tp->t_session);
2043	if (tp->t_session != NULL)
2044	    db_printf(" count %u leader %p tty %p sid %d login %s",
2045		tp->t_session->s_count, tp->t_session->s_leader,
2046		tp->t_session->s_ttyp, tp->t_session->s_sid,
2047		tp->t_session->s_login);
2048	db_printf("\n");
2049	db_printf("\tsessioncnt: %u\n", tp->t_sessioncnt);
2050	db_printf("\tdevswsoftc: %p\n", tp->t_devswsoftc);
2051	db_printf("\thooksoftc: %p\n", tp->t_hooksoftc);
2052	db_printf("\tdev: %p\n", tp->t_dev);
2053}
2054
2055/* DDB command to list TTYs. */
2056DB_SHOW_ALL_COMMAND(ttys, db_show_all_ttys)
2057{
2058	struct tty *tp;
2059	size_t isiz, osiz;
2060	int i, j;
2061
2062	/* Make the output look like `pstat -t'. */
2063	db_printf("PTR        ");
2064#if defined(__LP64__)
2065	db_printf("        ");
2066#endif
2067	db_printf("      LINE   INQ  CAN  LIN  LOW  OUTQ  USE  LOW   "
2068	    "COL  SESS  PGID STATE\n");
2069
2070	TAILQ_FOREACH(tp, &tty_list, t_list) {
2071		isiz = tp->t_inq.ti_nblocks * TTYINQ_DATASIZE;
2072		osiz = tp->t_outq.to_nblocks * TTYOUTQ_DATASIZE;
2073
2074		db_printf("%p %10s %5zu %4u %4u %4zu %5zu %4u %4zu %5u %5d %5d ",
2075		    tp,
2076		    tty_devname(tp),
2077		    isiz,
2078		    tp->t_inq.ti_linestart - tp->t_inq.ti_begin,
2079		    tp->t_inq.ti_end - tp->t_inq.ti_linestart,
2080		    isiz - tp->t_inlow,
2081		    osiz,
2082		    tp->t_outq.to_end - tp->t_outq.to_begin,
2083		    osiz - tp->t_outlow,
2084		    MIN(tp->t_column, 99999),
2085		    tp->t_session ? tp->t_session->s_sid : 0,
2086		    tp->t_pgrp ? tp->t_pgrp->pg_id : 0);
2087
2088		/* Flag bits. */
2089		for (i = j = 0; ttystates[i].flag; i++)
2090			if (tp->t_flags & ttystates[i].flag) {
2091				db_printf("%c", ttystates[i].val);
2092				j++;
2093			}
2094		if (j == 0)
2095			db_printf("-");
2096		db_printf("\n");
2097	}
2098}
2099#endif /* DDB */
2100