xref: /openbsd-src/sys/kern/tty_pty.c (revision db3296cf5c1dd9058ceecc3a29fe4aaa0bd26000)
1 /*	$OpenBSD: tty_pty.c,v 1.14 2003/07/22 01:03:12 mickey Exp $	*/
2 /*	$NetBSD: tty_pty.c,v 1.33.4.1 1996/06/02 09:08:11 mrg Exp $	*/
3 
4 /*
5  * Copyright (c) 1982, 1986, 1989, 1993
6  *	The Regents of the University of California.  All rights reserved.
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  * 3. Neither the name of the University nor the names of its contributors
17  *    may be used to endorse or promote products derived from this software
18  *    without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30  * SUCH DAMAGE.
31  *
32  *	@(#)tty_pty.c	8.4 (Berkeley) 2/20/95
33  */
34 
35 /*
36  * Pseudo-teletype Driver
37  * (Actually two drivers, requiring two entries in 'cdevsw')
38  */
39 
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/ioctl.h>
43 #include <sys/proc.h>
44 #include <sys/tty.h>
45 #include <sys/file.h>
46 #include <sys/uio.h>
47 #include <sys/kernel.h>
48 #include <sys/malloc.h>
49 #include <sys/vnode.h>
50 #include <sys/signalvar.h>
51 #include <sys/uio.h>
52 #include <sys/conf.h>
53 
54 #define BUFSIZ 100		/* Chunk size iomoved to/from user */
55 
56 /*
57  * pts == /dev/tty[pqrs]?
58  * ptc == /dev/pty[pqrs]?
59  */
60 struct	pt_softc {
61 	struct	tty *pt_tty;
62 	int	pt_flags;
63 	struct	selinfo pt_selr, pt_selw;
64 	u_char	pt_send;
65 	u_char	pt_ucntl;
66 } *pt_softc;
67 int	npty;
68 
69 #define	PF_PKT		0x08		/* packet mode */
70 #define	PF_STOPPED	0x10		/* user told stopped */
71 #define	PF_REMOTE	0x20		/* remote and flow controlled input */
72 #define	PF_NOSTOP	0x40
73 #define PF_UCNTL	0x80		/* user control mode */
74 
75 void	ptyattach(int);
76 void	ptcwakeup(struct tty *, int);
77 struct tty *ptytty(dev_t);
78 void	ptsstart(struct tty *);
79 
80 void	filt_ptcrdetach(struct knote *);
81 int	filt_ptcread(struct knote *, long);
82 void	filt_ptcwdetach(struct knote *);
83 int	filt_ptcwrite(struct knote *, long);
84 
85 /*
86  * Establish n (or default if n is 1) ptys in the system.
87  */
88 void
89 ptyattach(n)
90 	int n;
91 {
92 #define	DEFAULT_NPTY	32
93 
94 	/* maybe should allow 0 => none? */
95 	if (n <= 1)
96 		n = DEFAULT_NPTY;
97 	pt_softc = malloc(n * sizeof(struct pt_softc), M_DEVBUF, M_WAITOK);
98 	bzero(pt_softc, n * sizeof(struct pt_softc));
99 	npty = n;
100 }
101 
102 /*ARGSUSED*/
103 int
104 ptsopen(dev, flag, devtype, p)
105 	dev_t dev;
106 	int flag, devtype;
107 	struct proc *p;
108 {
109 	struct pt_softc *pti;
110 	register struct tty *tp;
111 	int error;
112 
113 	if (minor(dev) >= npty)
114 		return (ENXIO);
115 	pti = &pt_softc[minor(dev)];
116 	if (!pti->pt_tty) {
117 		tp = pti->pt_tty = ttymalloc();
118 		tty_attach(tp);
119 	}
120 	else
121 		tp = pti->pt_tty;
122 	if ((tp->t_state & TS_ISOPEN) == 0) {
123 		tp->t_state |= TS_WOPEN;
124 		ttychars(tp);		/* Set up default chars */
125 		tp->t_iflag = TTYDEF_IFLAG;
126 		tp->t_oflag = TTYDEF_OFLAG;
127 		tp->t_lflag = TTYDEF_LFLAG;
128 		tp->t_cflag = TTYDEF_CFLAG;
129 		tp->t_ispeed = tp->t_ospeed = TTYDEF_SPEED;
130 		ttsetwater(tp);		/* would be done in xxparam() */
131 	} else if (tp->t_state&TS_XCLUDE && p->p_ucred->cr_uid != 0)
132 		return (EBUSY);
133 	if (tp->t_oproc)			/* Ctrlr still around. */
134 		tp->t_state |= TS_CARR_ON;
135 	while ((tp->t_state & TS_CARR_ON) == 0) {
136 		tp->t_state |= TS_WOPEN;
137 		if (flag&FNONBLOCK)
138 			break;
139 		error = ttysleep(tp, &tp->t_rawq, TTIPRI | PCATCH,
140 				 ttopen, 0);
141 		if (error)
142 			return (error);
143 	}
144 	error = (*linesw[tp->t_line].l_open)(dev, tp);
145 	ptcwakeup(tp, FREAD|FWRITE);
146 	return (error);
147 }
148 
149 int
150 ptsclose(dev, flag, mode, p)
151 	dev_t dev;
152 	int flag, mode;
153 	struct proc *p;
154 {
155 	register struct pt_softc *pti = &pt_softc[minor(dev)];
156 	register struct tty *tp = pti->pt_tty;
157 	int error;
158 
159 	error = (*linesw[tp->t_line].l_close)(tp, flag);
160 	error |= ttyclose(tp);
161 	ptcwakeup(tp, FREAD|FWRITE);
162 	return (error);
163 }
164 
165 int
166 ptsread(dev, uio, flag)
167 	dev_t dev;
168 	struct uio *uio;
169 	int flag;
170 {
171 	struct proc *p = curproc;
172 	register struct pt_softc *pti = &pt_softc[minor(dev)];
173 	register struct tty *tp = pti->pt_tty;
174 	int error = 0;
175 
176 again:
177 	if (pti->pt_flags & PF_REMOTE) {
178 		while (isbackground(p, tp)) {
179 			if ((p->p_sigignore & sigmask(SIGTTIN)) ||
180 			    (p->p_sigmask & sigmask(SIGTTIN)) ||
181 			    p->p_pgrp->pg_jobc == 0 ||
182 			    p->p_flag & P_PPWAIT)
183 				return (EIO);
184 			pgsignal(p->p_pgrp, SIGTTIN, 1);
185 			error = ttysleep(tp, &lbolt,
186 					 TTIPRI | PCATCH, ttybg, 0);
187 			if (error)
188 				return (error);
189 		}
190 		if (tp->t_canq.c_cc == 0) {
191 			if (flag & IO_NDELAY)
192 				return (EWOULDBLOCK);
193 			error = ttysleep(tp, &tp->t_canq,
194 					 TTIPRI | PCATCH, ttyin, 0);
195 			if (error)
196 				return (error);
197 			goto again;
198 		}
199 		while (tp->t_canq.c_cc > 1 && uio->uio_resid > 0)
200 			if (ureadc(getc(&tp->t_canq), uio) < 0) {
201 				error = EFAULT;
202 				break;
203 			}
204 		if (tp->t_canq.c_cc == 1)
205 			(void) getc(&tp->t_canq);
206 		if (tp->t_canq.c_cc)
207 			return (error);
208 	} else
209 		if (tp->t_oproc)
210 			error = (*linesw[tp->t_line].l_read)(tp, uio, flag);
211 	ptcwakeup(tp, FWRITE);
212 	return (error);
213 }
214 
215 /*
216  * Write to pseudo-tty.
217  * Wakeups of controlling tty will happen
218  * indirectly, when tty driver calls ptsstart.
219  */
220 int
221 ptswrite(dev, uio, flag)
222 	dev_t dev;
223 	struct uio *uio;
224 	int flag;
225 {
226 	register struct pt_softc *pti = &pt_softc[minor(dev)];
227 	register struct tty *tp = pti->pt_tty;
228 
229 	if (tp->t_oproc == 0)
230 		return (EIO);
231 	return ((*linesw[tp->t_line].l_write)(tp, uio, flag));
232 }
233 
234 /*
235  * Start output on pseudo-tty.
236  * Wake up process selecting or sleeping for input from controlling tty.
237  */
238 void
239 ptsstart(tp)
240 	struct tty *tp;
241 {
242 	register struct pt_softc *pti = &pt_softc[minor(tp->t_dev)];
243 
244 	if (tp->t_state & TS_TTSTOP)
245 		return;
246 	if (pti->pt_flags & PF_STOPPED) {
247 		pti->pt_flags &= ~PF_STOPPED;
248 		pti->pt_send = TIOCPKT_START;
249 	}
250 	ptcwakeup(tp, FREAD);
251 }
252 
253 int
254 ptsstop(tp, flush)
255 	register struct tty *tp;
256 	int flush;
257 {
258 	struct pt_softc *pti = &pt_softc[minor(tp->t_dev)];
259 	int flag;
260 
261 	/* note: FLUSHREAD and FLUSHWRITE already ok */
262 	if (flush == 0) {
263 		flush = TIOCPKT_STOP;
264 		pti->pt_flags |= PF_STOPPED;
265 	} else
266 		pti->pt_flags &= ~PF_STOPPED;
267 	pti->pt_send |= flush;
268 	/* change of perspective */
269 	flag = 0;
270 	if (flush & FREAD)
271 		flag |= FWRITE;
272 	if (flush & FWRITE)
273 		flag |= FREAD;
274 	ptcwakeup(tp, flag);
275 	return 0;
276 }
277 
278 void
279 ptcwakeup(tp, flag)
280 	struct tty *tp;
281 	int flag;
282 {
283 	struct pt_softc *pti = &pt_softc[minor(tp->t_dev)];
284 
285 	if (flag & FREAD) {
286 		selwakeup(&pti->pt_selr);
287 		wakeup(&tp->t_outq.c_cf);
288 		KNOTE(&pti->pt_selr.si_note, 0);
289 	}
290 	if (flag & FWRITE) {
291 		selwakeup(&pti->pt_selw);
292 		wakeup(&tp->t_rawq.c_cf);
293 		KNOTE(&pti->pt_selw.si_note, 0);
294 	}
295 }
296 
297 int ptcopen(dev_t, int, int, struct proc *);
298 
299 /*ARGSUSED*/
300 int
301 ptcopen(dev, flag, devtype, p)
302 	dev_t dev;
303 	int flag, devtype;
304 	struct proc *p;
305 {
306 	struct pt_softc *pti;
307 	register struct tty *tp;
308 
309 	if (minor(dev) >= npty)
310 		return (ENXIO);
311 	pti = &pt_softc[minor(dev)];
312 	if (!pti->pt_tty) {
313 		tp = pti->pt_tty = ttymalloc();
314 		tty_attach(tp);
315 	}
316 	else
317 		tp = pti->pt_tty;
318 	if (tp->t_oproc)
319 		return (EIO);
320 	tp->t_oproc = ptsstart;
321 	(void)(*linesw[tp->t_line].l_modem)(tp, 1);
322 	tp->t_lflag &= ~EXTPROC;
323 	pti->pt_flags = 0;
324 	pti->pt_send = 0;
325 	pti->pt_ucntl = 0;
326 	return (0);
327 }
328 
329 /*ARGSUSED*/
330 int
331 ptcclose(dev, flag, devtype, p)
332 	dev_t dev;
333 	int flag, devtype;
334 	struct proc *p;
335 {
336 	register struct pt_softc *pti = &pt_softc[minor(dev)];
337 	register struct tty *tp = pti->pt_tty;
338 
339 	(void)(*linesw[tp->t_line].l_modem)(tp, 0);
340 	tp->t_state &= ~TS_CARR_ON;
341 	tp->t_oproc = 0;		/* mark closed */
342 	return (0);
343 }
344 
345 int
346 ptcread(dev, uio, flag)
347 	dev_t dev;
348 	struct uio *uio;
349 	int flag;
350 {
351 	register struct pt_softc *pti = &pt_softc[minor(dev)];
352 	register struct tty *tp = pti->pt_tty;
353 	char buf[BUFSIZ];
354 	int error = 0, cc;
355 
356 	/*
357 	 * We want to block until the slave
358 	 * is open, and there's something to read;
359 	 * but if we lost the slave or we're NBIO,
360 	 * then return the appropriate error instead.
361 	 */
362 	for (;;) {
363 		if (tp->t_state&TS_ISOPEN) {
364 			if (pti->pt_flags&PF_PKT && pti->pt_send) {
365 				error = ureadc((int)pti->pt_send, uio);
366 				if (error)
367 					return (error);
368 				if (pti->pt_send & TIOCPKT_IOCTL) {
369 					cc = min(uio->uio_resid,
370 						sizeof(tp->t_termios));
371 					uiomove(&tp->t_termios, cc, uio);
372 				}
373 				pti->pt_send = 0;
374 				return (0);
375 			}
376 			if (pti->pt_flags&PF_UCNTL && pti->pt_ucntl) {
377 				error = ureadc((int)pti->pt_ucntl, uio);
378 				if (error)
379 					return (error);
380 				pti->pt_ucntl = 0;
381 				return (0);
382 			}
383 			if (tp->t_outq.c_cc && (tp->t_state&TS_TTSTOP) == 0)
384 				break;
385 		}
386 		if ((tp->t_state&TS_CARR_ON) == 0)
387 			return (0);	/* EOF */
388 		if (flag & IO_NDELAY)
389 			return (EWOULDBLOCK);
390 		error = tsleep(&tp->t_outq.c_cf, TTIPRI | PCATCH,
391 			       ttyin, 0);
392 		if (error)
393 			return (error);
394 	}
395 	if (pti->pt_flags & (PF_PKT|PF_UCNTL))
396 		error = ureadc(0, uio);
397 	while (uio->uio_resid > 0 && error == 0) {
398 		cc = q_to_b(&tp->t_outq, buf, min(uio->uio_resid, BUFSIZ));
399 		if (cc <= 0)
400 			break;
401 		error = uiomove(buf, cc, uio);
402 	}
403 	if (tp->t_outq.c_cc <= tp->t_lowat) {
404 		if (tp->t_state&TS_ASLEEP) {
405 			tp->t_state &= ~TS_ASLEEP;
406 			wakeup(&tp->t_outq);
407 		}
408 		selwakeup(&tp->t_wsel);
409 	}
410 	return (error);
411 }
412 
413 
414 int
415 ptcwrite(dev, uio, flag)
416 	dev_t dev;
417 	register struct uio *uio;
418 	int flag;
419 {
420 	register struct pt_softc *pti = &pt_softc[minor(dev)];
421 	register struct tty *tp = pti->pt_tty;
422 	register u_char *cp = NULL;
423 	register int cc = 0;
424 	u_char locbuf[BUFSIZ];
425 	int cnt = 0;
426 	int error = 0;
427 
428 again:
429 	if ((tp->t_state&TS_ISOPEN) == 0)
430 		goto block;
431 	if (pti->pt_flags & PF_REMOTE) {
432 		if (tp->t_canq.c_cc)
433 			goto block;
434 		while (uio->uio_resid > 0 && tp->t_canq.c_cc < TTYHOG - 1) {
435 			if (cc == 0) {
436 				cc = min(uio->uio_resid, BUFSIZ);
437 				cc = min(cc, TTYHOG - 1 - tp->t_canq.c_cc);
438 				cp = locbuf;
439 				error = uiomove(cp, cc, uio);
440 				if (error)
441 					return (error);
442 				/* check again for safety */
443 				if ((tp->t_state&TS_ISOPEN) == 0)
444 					return (EIO);
445 			}
446 			if (cc)
447 				(void) b_to_q((char *)cp, cc, &tp->t_canq);
448 			cc = 0;
449 		}
450 		(void) putc(0, &tp->t_canq);
451 		ttwakeup(tp);
452 		wakeup(&tp->t_canq);
453 		return (0);
454 	}
455 	while (uio->uio_resid > 0) {
456 		if (cc == 0) {
457 			cc = min(uio->uio_resid, BUFSIZ);
458 			cp = locbuf;
459 			error = uiomove(cp, cc, uio);
460 			if (error)
461 				return (error);
462 			/* check again for safety */
463 			if ((tp->t_state&TS_ISOPEN) == 0)
464 				return (EIO);
465 		}
466 		while (cc > 0) {
467 			if ((tp->t_rawq.c_cc + tp->t_canq.c_cc) >= TTYHOG - 2 &&
468 			   (tp->t_canq.c_cc > 0 || !ISSET(tp->t_lflag, ICANON))) {
469 				wakeup(&tp->t_rawq);
470 				goto block;
471 			}
472 			(*linesw[tp->t_line].l_rint)(*cp++, tp);
473 			cnt++;
474 			cc--;
475 		}
476 		cc = 0;
477 	}
478 	return (0);
479 block:
480 	/*
481 	 * Come here to wait for slave to open, for space
482 	 * in outq, or space in rawq.
483 	 */
484 	if ((tp->t_state&TS_CARR_ON) == 0)
485 		return (EIO);
486 	if (flag & IO_NDELAY) {
487 		/* adjust for data copied in but not written */
488 		uio->uio_resid += cc;
489 		if (cnt == 0)
490 			return (EWOULDBLOCK);
491 		return (0);
492 	}
493 	error = tsleep(&tp->t_rawq.c_cf, TTOPRI | PCATCH,
494 		       ttyout, 0);
495 	if (error) {
496 		/* adjust for data copied in but not written */
497 		uio->uio_resid += cc;
498 		return (error);
499 	}
500 	goto again;
501 }
502 
503 int
504 ptcselect(dev, rw, p)
505 	dev_t dev;
506 	int rw;
507 	struct proc *p;
508 {
509 	register struct pt_softc *pti = &pt_softc[minor(dev)];
510 	register struct tty *tp = pti->pt_tty;
511 	int s;
512 
513 	if ((tp->t_state&TS_CARR_ON) == 0)
514 		return (1);
515 	switch (rw) {
516 
517 	case FREAD:
518 		/*
519 		 * Need to block timeouts (ttrstart).
520 		 */
521 		s = spltty();
522 		if ((tp->t_state&TS_ISOPEN) &&
523 		     tp->t_outq.c_cc && (tp->t_state&TS_TTSTOP) == 0) {
524 			splx(s);
525 			return (1);
526 		}
527 		splx(s);
528 		/* FALLTHROUGH */
529 
530 	case 0:					/* exceptional */
531 		if ((tp->t_state&TS_ISOPEN) &&
532 		    (((pti->pt_flags & PF_PKT) && pti->pt_send) ||
533 		     ((pti->pt_flags & PF_UCNTL) && pti->pt_ucntl)))
534 			return (1);
535 		selrecord(p, &pti->pt_selr);
536 		break;
537 
538 
539 	case FWRITE:
540 		if (tp->t_state&TS_ISOPEN) {
541 			if (pti->pt_flags & PF_REMOTE) {
542 			    if (tp->t_canq.c_cc == 0)
543 				return (1);
544 			} else {
545 			    if (tp->t_rawq.c_cc + tp->t_canq.c_cc < TTYHOG-2)
546 				    return (1);
547 			    if (tp->t_canq.c_cc == 0 && ISSET(tp->t_lflag, ICANON))
548 				    return (1);
549 			}
550 		}
551 		selrecord(p, &pti->pt_selw);
552 		break;
553 
554 	}
555 	return (0);
556 }
557 
558 void
559 filt_ptcrdetach(struct knote *kn)
560 {
561 	struct pt_softc *pti = (struct pt_softc *)kn->kn_hook;
562 	int s;
563 
564 	s = spltty();
565 	SLIST_REMOVE(&pti->pt_selr.si_note, kn, knote, kn_selnext);
566 	splx(s);
567 }
568 
569 int
570 filt_ptcread(struct knote *kn, long hint)
571 {
572 	struct pt_softc *pti = (struct pt_softc *)kn->kn_hook;
573 	struct tty *tp;
574 
575 	tp = pti->pt_tty;
576 	kn->kn_data = 0;
577 
578 	if (ISSET(tp->t_state, TS_ISOPEN)) {
579 		if (!ISSET(tp->t_state, TS_TTSTOP))
580 			kn->kn_data = tp->t_outq.c_cc;
581 		if (((pti->pt_flags & PF_PKT) && pti->pt_send) ||
582 		    ((pti->pt_flags & PF_UCNTL) && pti->pt_ucntl))
583 			kn->kn_data++;
584 	}
585 	return (kn->kn_data > 0);
586 }
587 
588 void
589 filt_ptcwdetach(struct knote *kn)
590 {
591 	struct pt_softc *pti = (struct pt_softc *)kn->kn_hook;
592 	int s;
593 
594 	s = spltty();
595 	SLIST_REMOVE(&pti->pt_selw.si_note, kn, knote, kn_selnext);
596 	splx(s);
597 }
598 
599 int
600 filt_ptcwrite(struct knote *kn, long hint)
601 {
602 	struct pt_softc *pti = (struct pt_softc *)kn->kn_hook;
603 	struct tty *tp;
604 
605 	tp = pti->pt_tty;
606 	kn->kn_data = 0;
607 
608 	if (ISSET(tp->t_state, TS_ISOPEN)) {
609 		if (ISSET(pti->pt_flags, PF_REMOTE)) {
610 			if (tp->t_canq.c_cc == 0)
611 				kn->kn_data = tp->t_canq.c_cn;
612 		} else if (tp->t_rawq.c_cc + tp->t_canq.c_cc < TTYHOG-2)
613 			kn->kn_data = tp->t_canq.c_cn -
614 			    (tp->t_rawq.c_cc + tp->t_canq.c_cc);
615 	}
616 
617 	return (kn->kn_data > 0);
618 }
619 
620 struct filterops ptcread_filtops =
621 	{ 1, NULL, filt_ptcrdetach, filt_ptcread };
622 struct filterops ptcwrite_filtops =
623 	{ 1, NULL, filt_ptcwdetach, filt_ptcwrite };
624 
625 int
626 ptckqfilter(dev_t dev, struct knote *kn)
627 {
628 	struct pt_softc *pti = &pt_softc[minor(dev)];
629 	struct klist *klist;
630 	int s;
631 
632 	switch (kn->kn_filter) {
633 	case EVFILT_READ:
634 		klist = &pti->pt_selr.si_note;
635 		kn->kn_fop = &ptcread_filtops;
636 		break;
637 	case EVFILT_WRITE:
638 		klist = &pti->pt_selw.si_note;
639 		kn->kn_fop = &ptcwrite_filtops;
640 		break;
641 	default:
642 		return (1);
643 	}
644 
645 	kn->kn_hook = (caddr_t)pti;
646 
647 	s = spltty();
648 	SLIST_INSERT_HEAD(klist, kn, kn_selnext);
649 	splx(s);
650 
651 	return (0);
652 }
653 
654 struct tty *
655 ptytty(dev)
656 	dev_t dev;
657 {
658 	register struct pt_softc *pti = &pt_softc[minor(dev)];
659 	register struct tty *tp = pti->pt_tty;
660 
661 	return (tp);
662 }
663 
664 /*ARGSUSED*/
665 int
666 ptyioctl(dev, cmd, data, flag, p)
667 	dev_t dev;
668 	u_long cmd;
669 	caddr_t data;
670 	int flag;
671 	struct proc *p;
672 {
673 	register struct pt_softc *pti = &pt_softc[minor(dev)];
674 	register struct tty *tp = pti->pt_tty;
675 	register u_char *cc = tp->t_cc;
676 	int stop, error;
677 
678 	/*
679 	 * IF CONTROLLER STTY THEN MUST FLUSH TO PREVENT A HANG.
680 	 * ttywflush(tp) will hang if there are characters in the outq.
681 	 */
682 	if (cmd == TIOCEXT) {
683 		/*
684 		 * When the EXTPROC bit is being toggled, we need
685 		 * to send an TIOCPKT_IOCTL if the packet driver
686 		 * is turned on.
687 		 */
688 		if (*(int *)data) {
689 			if (pti->pt_flags & PF_PKT) {
690 				pti->pt_send |= TIOCPKT_IOCTL;
691 				ptcwakeup(tp, FREAD);
692 			}
693 			tp->t_lflag |= EXTPROC;
694 		} else {
695 			if ((tp->t_lflag & EXTPROC) &&
696 			    (pti->pt_flags & PF_PKT)) {
697 				pti->pt_send |= TIOCPKT_IOCTL;
698 				ptcwakeup(tp, FREAD);
699 			}
700 			tp->t_lflag &= ~EXTPROC;
701 		}
702 		return(0);
703 	} else
704 	if (cdevsw[major(dev)].d_open == ptcopen)
705 		switch (cmd) {
706 
707 		case TIOCGPGRP:
708 #ifdef COMPAT_SUNOS
709 			{
710 			/*
711 			 * I'm not sure about SunOS TIOCGPGRP semantics
712 			 * on PTYs, but it's something like this:
713 			 */
714 			extern struct emul emul_sunos;
715 			if (p->p_emul == &emul_sunos && tp->t_pgrp == 0)
716 				return (EIO);
717 			*(int *)data = tp->t_pgrp->pg_id;
718 			return (0);
719 			}
720 #endif
721 			/*
722 			 * We aviod calling ttioctl on the controller since,
723 			 * in that case, tp must be the controlling terminal.
724 			 */
725 			*(int *)data = tp->t_pgrp ? tp->t_pgrp->pg_id : 0;
726 			return (0);
727 
728 		case TIOCPKT:
729 			if (*(int *)data) {
730 				if (pti->pt_flags & PF_UCNTL)
731 					return (EINVAL);
732 				pti->pt_flags |= PF_PKT;
733 			} else
734 				pti->pt_flags &= ~PF_PKT;
735 			return (0);
736 
737 		case TIOCUCNTL:
738 			if (*(int *)data) {
739 				if (pti->pt_flags & PF_PKT)
740 					return (EINVAL);
741 				pti->pt_flags |= PF_UCNTL;
742 			} else
743 				pti->pt_flags &= ~PF_UCNTL;
744 			return (0);
745 
746 		case TIOCREMOTE:
747 			if (*(int *)data)
748 				pti->pt_flags |= PF_REMOTE;
749 			else
750 				pti->pt_flags &= ~PF_REMOTE;
751 			ttyflush(tp, FREAD|FWRITE);
752 			return (0);
753 
754 #ifdef COMPAT_OLDTTY
755 		case TIOCSETP:
756 		case TIOCSETN:
757 #endif
758 		case TIOCSETD:
759 		case TIOCSETA:
760 		case TIOCSETAW:
761 		case TIOCSETAF:
762 			ndflush(&tp->t_outq, tp->t_outq.c_cc);
763 			break;
764 
765 		case TIOCSIG:
766 			if (*(unsigned int *)data >= NSIG)
767 				return(EINVAL);
768 			if ((tp->t_lflag&NOFLSH) == 0)
769 				ttyflush(tp, FREAD|FWRITE);
770 			pgsignal(tp->t_pgrp, *(unsigned int *)data, 1);
771 			if ((*(unsigned int *)data == SIGINFO) &&
772 			    ((tp->t_lflag&NOKERNINFO) == 0))
773 				ttyinfo(tp);
774 			return(0);
775 		}
776 	error = (*linesw[tp->t_line].l_ioctl)(tp, cmd, data, flag, p);
777 	if (error < 0)
778 		 error = ttioctl(tp, cmd, data, flag, p);
779 	if (error < 0) {
780 		if (pti->pt_flags & PF_UCNTL &&
781 		    (cmd & ~0xff) == UIOCCMD(0)) {
782 			if (cmd & 0xff) {
783 				pti->pt_ucntl = (u_char)cmd;
784 				ptcwakeup(tp, FREAD);
785 			}
786 			return (0);
787 		}
788 		error = ENOTTY;
789 	}
790 	/*
791 	 * If external processing and packet mode send ioctl packet.
792 	 */
793 	if ((tp->t_lflag&EXTPROC) && (pti->pt_flags & PF_PKT)) {
794 		switch(cmd) {
795 		case TIOCSETA:
796 		case TIOCSETAW:
797 		case TIOCSETAF:
798 #ifdef COMPAT_OLDTTY
799 		case TIOCSETP:
800 		case TIOCSETN:
801 		case TIOCSETC:
802 		case TIOCSLTC:
803 		case TIOCLBIS:
804 		case TIOCLBIC:
805 		case TIOCLSET:
806 #endif
807 			pti->pt_send |= TIOCPKT_IOCTL;
808 			ptcwakeup(tp, FREAD);
809 		default:
810 			break;
811 		}
812 	}
813 	stop = (tp->t_iflag & IXON) && CCEQ(cc[VSTOP], CTRL('s'))
814 		&& CCEQ(cc[VSTART], CTRL('q'));
815 	if (pti->pt_flags & PF_NOSTOP) {
816 		if (stop) {
817 			pti->pt_send &= ~TIOCPKT_NOSTOP;
818 			pti->pt_send |= TIOCPKT_DOSTOP;
819 			pti->pt_flags &= ~PF_NOSTOP;
820 			ptcwakeup(tp, FREAD);
821 		}
822 	} else {
823 		if (!stop) {
824 			pti->pt_send &= ~TIOCPKT_DOSTOP;
825 			pti->pt_send |= TIOCPKT_NOSTOP;
826 			pti->pt_flags |= PF_NOSTOP;
827 			ptcwakeup(tp, FREAD);
828 		}
829 	}
830 	return (error);
831 }
832