xref: /netbsd-src/sys/kern/tty_pty.c (revision ae1bfcddc410612bc8c58b807e1830becb69a24c) 
1 /*
2  * Copyright (c) 1982, 1986, 1989, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  *
33  *	from: @(#)tty_pty.c	8.2 (Berkeley) 9/23/93
34  *	$Id: tty_pty.c,v 1.22 1994/05/12 03:48:36 cgd Exp $
35  */
36 
37 /*
38  * Pseudo-teletype Driver
39  * (Actually two drivers, requiring two entries in 'cdevsw')
40  */
41 #include "pty.h"		/* XXX */
42 
43 #include <sys/param.h>
44 #include <sys/systm.h>
45 #include <sys/ioctl.h>
46 #include <sys/proc.h>
47 #include <sys/tty.h>
48 #include <sys/conf.h>
49 #include <sys/file.h>
50 #include <sys/uio.h>
51 #include <sys/kernel.h>
52 #include <sys/vnode.h>
53 
54 #if NPTY == 1
55 #undef NPTY
56 #define	NPTY	32		/* crude XXX */
57 #endif
58 
59 #define BUFSIZ 100		/* Chunk size iomoved to/from user */
60 
61 /*
62  * pts == /dev/tty[pqrs]?
63  * ptc == /dev/pty[pqrs]?
64  */
65 struct	tty *pt_tty[NPTY];	/* XXX */
66 struct	pt_ioctl {
67 	int	pt_flags;
68 	struct	selinfo pt_selr, pt_selw;
69 	u_char	pt_send;
70 	u_char	pt_ucntl;
71 } pt_ioctl[NPTY];		/* XXX */
72 int	npty = NPTY;		/* for pstat -t */
73 
74 #define	PF_PKT		0x08		/* packet mode */
75 #define	PF_STOPPED	0x10		/* user told stopped */
76 #define	PF_REMOTE	0x20		/* remote and flow controlled input */
77 #define	PF_NOSTOP	0x40
78 #define PF_UCNTL	0x80		/* user control mode */
79 
80 void	ptsstop __P((struct tty *, int));
81 
82 /*
83  * Establish n (or default if n is 1) ptys in the system.
84  *
85  * XXX cdevsw & pstat require the array `pty[]' to be an array
86  */
87 void
88 ptyattach(n)
89 	int n;
90 {
91 #ifdef notyet
92 	char *mem;
93 	register u_long ntb;
94 #define	DEFAULT_NPTY	32
95 
96 	/* maybe should allow 0 => none? */
97 	if (n <= 1)
98 		n = DEFAULT_NPTY;
99 	ntb = n * sizeof(struct tty);
100 	mem = malloc(ntb + ALIGNBYTES + n * sizeof(struct pt_ioctl),
101 	    M_DEVBUF, M_WAITOK);
102 	pt_tty = (struct tty *)mem;
103 	mem = (char *)ALIGN(mem + ntb);
104 	pt_ioctl = (struct pt_ioctl *)mem;
105 	npty = n;
106 #endif
107 }
108 
109 /*ARGSUSED*/
110 ptsopen(dev, flag, devtype, p)
111 	dev_t dev;
112 	int flag, devtype;
113 	struct proc *p;
114 {
115 	register struct tty *tp;
116 	int error;
117 
118 	if (minor(dev) >= npty)
119 		return (ENXIO);
120 	if (!pt_tty[minor(dev)]) {
121 		tp = pt_tty[minor(dev)] = ttymalloc();
122 	} else
123 		tp = pt_tty[minor(dev)];
124 	if ((tp->t_state & TS_ISOPEN) == 0) {
125 		tp->t_state |= TS_WOPEN;
126 		ttychars(tp);		/* Set up default chars */
127 		tp->t_iflag = TTYDEF_IFLAG;
128 		tp->t_oflag = TTYDEF_OFLAG;
129 		tp->t_lflag = TTYDEF_LFLAG;
130 		tp->t_cflag = TTYDEF_CFLAG;
131 		tp->t_ispeed = tp->t_ospeed = TTYDEF_SPEED;
132 		ttsetwater(tp);		/* would be done in xxparam() */
133 	} else if (tp->t_state&TS_XCLUDE && p->p_ucred->cr_uid != 0)
134 		return (EBUSY);
135 	if (tp->t_oproc)			/* Ctrlr still around. */
136 		tp->t_state |= TS_CARR_ON;
137 	while ((tp->t_state & TS_CARR_ON) == 0) {
138 		tp->t_state |= TS_WOPEN;
139 		if (flag&FNONBLOCK)
140 			break;
141 		if (error = ttysleep(tp, (caddr_t)&tp->t_rawq, TTIPRI | PCATCH,
142 		    ttopen, 0))
143 			return (error);
144 	}
145 	error = (*linesw[tp->t_line].l_open)(dev, tp);
146 	ptcwakeup(tp, FREAD|FWRITE);
147 	return (error);
148 }
149 
150 ptsclose(dev, flag, mode, p)
151 	dev_t dev;
152 	int flag, mode;
153 	struct proc *p;
154 {
155 	register struct tty *tp;
156 	int err;
157 
158 	tp = pt_tty[minor(dev)];
159 	err = (*linesw[tp->t_line].l_close)(tp, flag);
160 	err |= ttyclose(tp);
161 	ptcwakeup(tp, FREAD|FWRITE);
162 	return (err);
163 }
164 
165 ptsread(dev, uio, flag)
166 	dev_t dev;
167 	struct uio *uio;
168 	int flag;
169 {
170 	struct proc *p = curproc;
171 	register struct tty *tp = pt_tty[minor(dev)];
172 	register struct pt_ioctl *pti = &pt_ioctl[minor(dev)];
173 	int error = 0;
174 
175 again:
176 	if (pti->pt_flags & PF_REMOTE) {
177 		while (isbackground(p, tp)) {
178 			if ((p->p_sigignore & sigmask(SIGTTIN)) ||
179 			    (p->p_sigmask & sigmask(SIGTTIN)) ||
180 			    p->p_pgrp->pg_jobc == 0 ||
181 			    p->p_flag & P_PPWAIT)
182 				return (EIO);
183 			pgsignal(p->p_pgrp, SIGTTIN, 1);
184 			if (error = ttysleep(tp, (caddr_t)&lbolt,
185 			    TTIPRI | PCATCH, ttybg, 0))
186 				return (error);
187 		}
188 		if (tp->t_canq.c_cc == 0) {
189 			if (flag & IO_NDELAY)
190 				return (EWOULDBLOCK);
191 			if (error = ttysleep(tp, (caddr_t)&tp->t_canq,
192 			    TTIPRI | PCATCH, ttyin, 0))
193 				return (error);
194 			goto again;
195 		}
196 		while (tp->t_canq.c_cc > 1 && uio->uio_resid > 0)
197 			if (ureadc(getc(&tp->t_canq), uio) < 0) {
198 				error = EFAULT;
199 				break;
200 			}
201 		if (tp->t_canq.c_cc == 1)
202 			(void) getc(&tp->t_canq);
203 		if (tp->t_canq.c_cc)
204 			return (error);
205 	} else
206 		if (tp->t_oproc)
207 			error = (*linesw[tp->t_line].l_read)(tp, uio, flag);
208 	ptcwakeup(tp, FWRITE);
209 	return (error);
210 }
211 
212 /*
213  * Write to pseudo-tty.
214  * Wakeups of controlling tty will happen
215  * indirectly, when tty driver calls ptsstart.
216  */
217 ptswrite(dev, uio, flag)
218 	dev_t dev;
219 	struct uio *uio;
220 	int flag;
221 {
222 	register struct tty *tp;
223 
224 	tp = pt_tty[minor(dev)];
225 	if (tp->t_oproc == 0)
226 		return (EIO);
227 	return ((*linesw[tp->t_line].l_write)(tp, uio, flag));
228 }
229 
230 /*
231  * Start output on pseudo-tty.
232  * Wake up process selecting or sleeping for input from controlling tty.
233  */
234 void
235 ptsstart(tp)
236 	struct tty *tp;
237 {
238 	register struct pt_ioctl *pti = &pt_ioctl[minor(tp->t_dev)];
239 
240 	if (tp->t_state & TS_TTSTOP)
241 		return;
242 	if (pti->pt_flags & PF_STOPPED) {
243 		pti->pt_flags &= ~PF_STOPPED;
244 		pti->pt_send = TIOCPKT_START;
245 	}
246 	ptcwakeup(tp, FREAD);
247 }
248 
249 ptcwakeup(tp, flag)
250 	struct tty *tp;
251 	int flag;
252 {
253 	struct pt_ioctl *pti = &pt_ioctl[minor(tp->t_dev)];
254 
255 	if (flag & FREAD) {
256 		selwakeup(&pti->pt_selr);
257 		wakeup((caddr_t)&tp->t_outq.c_cf);
258 	}
259 	if (flag & FWRITE) {
260 		selwakeup(&pti->pt_selw);
261 		wakeup((caddr_t)&tp->t_rawq.c_cf);
262 	}
263 }
264 
265 /*ARGSUSED*/
266 #ifdef __STDC__
267 ptcopen(dev_t dev, int flag, int devtype, struct proc *p)
268 #else
269 ptcopen(dev, flag, devtype, p)
270 	dev_t dev;
271 	int flag, devtype;
272 	struct proc *p;
273 #endif
274 {
275 	register struct tty *tp;
276 	struct pt_ioctl *pti;
277 
278 	if (minor(dev) >= npty)
279 		return (ENXIO);
280 	if(!pt_tty[minor(dev)]) {
281 		tp = pt_tty[minor(dev)] = ttymalloc();
282 	} else
283 		tp = pt_tty[minor(dev)];
284 	if (tp->t_oproc)
285 		return (EIO);
286 	tp->t_oproc = ptsstart;
287 	(void)(*linesw[tp->t_line].l_modem)(tp, 1);
288 	tp->t_lflag &= ~EXTPROC;
289 	pti = &pt_ioctl[minor(dev)];
290 	pti->pt_flags = 0;
291 	pti->pt_send = 0;
292 	pti->pt_ucntl = 0;
293 	return (0);
294 }
295 
296 ptcclose(dev)
297 	dev_t dev;
298 {
299 	register struct tty *tp;
300 
301 	tp = pt_tty[minor(dev)];
302 	(void)(*linesw[tp->t_line].l_modem)(tp, 0);
303 	tp->t_state &= ~TS_CARR_ON;
304 	tp->t_oproc = 0;		/* mark closed */
305 	return (0);
306 }
307 
308 ptcread(dev, uio, flag)
309 	dev_t dev;
310 	struct uio *uio;
311 	int flag;
312 {
313 	register struct tty *tp = pt_tty[minor(dev)];
314 	struct pt_ioctl *pti = &pt_ioctl[minor(dev)];
315 	char buf[BUFSIZ];
316 	int error = 0, cc;
317 
318 	/*
319 	 * We want to block until the slave
320 	 * is open, and there's something to read;
321 	 * but if we lost the slave or we're NBIO,
322 	 * then return the appropriate error instead.
323 	 */
324 	for (;;) {
325 		if (tp->t_state&TS_ISOPEN) {
326 			if (pti->pt_flags&PF_PKT && pti->pt_send) {
327 				error = ureadc((int)pti->pt_send, uio);
328 				if (error)
329 					return (error);
330 				if (pti->pt_send & TIOCPKT_IOCTL) {
331 					cc = min(uio->uio_resid,
332 						sizeof(tp->t_termios));
333 					uiomove(&tp->t_termios, cc, uio);
334 				}
335 				pti->pt_send = 0;
336 				return (0);
337 			}
338 			if (pti->pt_flags&PF_UCNTL && pti->pt_ucntl) {
339 				error = ureadc((int)pti->pt_ucntl, uio);
340 				if (error)
341 					return (error);
342 				pti->pt_ucntl = 0;
343 				return (0);
344 			}
345 			if (tp->t_outq.c_cc && (tp->t_state&TS_TTSTOP) == 0)
346 				break;
347 		}
348 		if ((tp->t_state&TS_CARR_ON) == 0)
349 			return (0);	/* EOF */
350 		if (flag & IO_NDELAY)
351 			return (EWOULDBLOCK);
352 		if (error = tsleep((caddr_t)&tp->t_outq.c_cf, TTIPRI | PCATCH,
353 		    ttyin, 0))
354 			return (error);
355 	}
356 	if (pti->pt_flags & (PF_PKT|PF_UCNTL))
357 		error = ureadc(0, uio);
358 	while (uio->uio_resid > 0 && error == 0) {
359 		cc = q_to_b(&tp->t_outq, buf, min(uio->uio_resid, BUFSIZ));
360 		if (cc <= 0)
361 			break;
362 		error = uiomove(buf, cc, uio);
363 	}
364 	if (tp->t_outq.c_cc <= tp->t_lowat) {
365 		if (tp->t_state&TS_ASLEEP) {
366 			tp->t_state &= ~TS_ASLEEP;
367 			wakeup((caddr_t)&tp->t_outq);
368 		}
369 		selwakeup(&tp->t_wsel);
370 	}
371 	return (error);
372 }
373 
374 void
375 ptsstop(tp, flush)
376 	register struct tty *tp;
377 	int flush;
378 {
379 	struct pt_ioctl *pti = &pt_ioctl[minor(tp->t_dev)];
380 	int flag;
381 
382 	/* note: FLUSHREAD and FLUSHWRITE already ok */
383 	if (flush == 0) {
384 		flush = TIOCPKT_STOP;
385 		pti->pt_flags |= PF_STOPPED;
386 	} else
387 		pti->pt_flags &= ~PF_STOPPED;
388 	pti->pt_send |= flush;
389 	/* change of perspective */
390 	flag = 0;
391 	if (flush & FREAD)
392 		flag |= FWRITE;
393 	if (flush & FWRITE)
394 		flag |= FREAD;
395 	ptcwakeup(tp, flag);
396 }
397 
398 ptcselect(dev, rw, p)
399 	dev_t dev;
400 	int rw;
401 	struct proc *p;
402 {
403 	register struct tty *tp = pt_tty[minor(dev)];
404 	struct pt_ioctl *pti = &pt_ioctl[minor(dev)];
405 	int s;
406 
407 	if ((tp->t_state&TS_CARR_ON) == 0)
408 		return (1);
409 	switch (rw) {
410 
411 	case FREAD:
412 		/*
413 		 * Need to block timeouts (ttrstart).
414 		 */
415 		s = spltty();
416 		if ((tp->t_state&TS_ISOPEN) &&
417 		     tp->t_outq.c_cc && (tp->t_state&TS_TTSTOP) == 0) {
418 			splx(s);
419 			return (1);
420 		}
421 		splx(s);
422 		/* FALLTHROUGH */
423 
424 	case 0:					/* exceptional */
425 		if ((tp->t_state&TS_ISOPEN) &&
426 		    (pti->pt_flags&PF_PKT && pti->pt_send ||
427 		     pti->pt_flags&PF_UCNTL && pti->pt_ucntl))
428 			return (1);
429 		selrecord(p, &pti->pt_selr);
430 		break;
431 
432 
433 	case FWRITE:
434 		if (tp->t_state&TS_ISOPEN) {
435 			if (pti->pt_flags & PF_REMOTE) {
436 			    if (tp->t_canq.c_cc == 0)
437 				return (1);
438 			} else {
439 			    if (tp->t_rawq.c_cc + tp->t_canq.c_cc < TTYHOG-2)
440 				    return (1);
441 			    if (tp->t_canq.c_cc == 0 && (tp->t_iflag&ICANON))
442 				    return (1);
443 			}
444 		}
445 		selrecord(p, &pti->pt_selw);
446 		break;
447 
448 	}
449 	return (0);
450 }
451 
452 ptcwrite(dev, uio, flag)
453 	dev_t dev;
454 	register struct uio *uio;
455 	int flag;
456 {
457 	register struct tty *tp = pt_tty[minor(dev)];
458 	register u_char *cp;
459 	register int cc = 0;
460 	u_char locbuf[BUFSIZ];
461 	int cnt = 0;
462 	struct pt_ioctl *pti = &pt_ioctl[minor(dev)];
463 	int error = 0;
464 
465 again:
466 	if ((tp->t_state&TS_ISOPEN) == 0)
467 		goto block;
468 	if (pti->pt_flags & PF_REMOTE) {
469 		if (tp->t_canq.c_cc)
470 			goto block;
471 		while (uio->uio_resid > 0 && tp->t_canq.c_cc < TTYHOG - 1) {
472 			if (cc == 0) {
473 				cc = min(uio->uio_resid, BUFSIZ);
474 				cc = min(cc, TTYHOG - 1 - tp->t_canq.c_cc);
475 				cp = locbuf;
476 				error = uiomove((caddr_t)cp, cc, uio);
477 				if (error)
478 					return (error);
479 				/* check again for safety */
480 				if ((tp->t_state&TS_ISOPEN) == 0)
481 					return (EIO);
482 			}
483 			if (cc)
484 				(void) b_to_q((char *)cp, cc, &tp->t_canq);
485 			cc = 0;
486 		}
487 		(void) putc(0, &tp->t_canq);
488 		ttwakeup(tp);
489 		wakeup((caddr_t)&tp->t_canq);
490 		return (0);
491 	}
492 	while (uio->uio_resid > 0) {
493 		if (cc == 0) {
494 			cc = min(uio->uio_resid, BUFSIZ);
495 			cp = locbuf;
496 			error = uiomove((caddr_t)cp, cc, uio);
497 			if (error)
498 				return (error);
499 			/* check again for safety */
500 			if ((tp->t_state&TS_ISOPEN) == 0)
501 				return (EIO);
502 		}
503 		while (cc > 0) {
504 			if ((tp->t_rawq.c_cc + tp->t_canq.c_cc) >= TTYHOG - 2 &&
505 			   (tp->t_canq.c_cc > 0 || !(tp->t_iflag&ICANON))) {
506 				wakeup((caddr_t)&tp->t_rawq);
507 				goto block;
508 			}
509 			(*linesw[tp->t_line].l_rint)(*cp++, tp);
510 			cnt++;
511 			cc--;
512 		}
513 		cc = 0;
514 	}
515 	return (0);
516 block:
517 	/*
518 	 * Come here to wait for slave to open, for space
519 	 * in outq, or space in rawq.
520 	 */
521 	if ((tp->t_state&TS_CARR_ON) == 0)
522 		return (EIO);
523 	if (flag & IO_NDELAY) {
524 		/* adjust for data copied in but not written */
525 		uio->uio_resid += cc;
526 		if (cnt == 0)
527 			return (EWOULDBLOCK);
528 		return (0);
529 	}
530 	if (error = tsleep((caddr_t)&tp->t_rawq.c_cf, TTOPRI | PCATCH,
531 	    ttyout, 0)) {
532 		/* adjust for data copied in but not written */
533 		uio->uio_resid += cc;
534 		return (error);
535 	}
536 	goto again;
537 }
538 
539 /*ARGSUSED*/
540 ptyioctl(dev, cmd, data, flag, p)
541 	dev_t dev;
542 	int cmd;
543 	caddr_t data;
544 	int flag;
545 	struct proc *p;
546 {
547 	register struct tty *tp = pt_tty[minor(dev)];
548 	register struct pt_ioctl *pti = &pt_ioctl[minor(dev)];
549 	register u_char *cc = tp->t_cc;
550 	int stop, error;
551 
552 	/*
553 	 * IF CONTROLLER STTY THEN MUST FLUSH TO PREVENT A HANG.
554 	 * ttywflush(tp) will hang if there are characters in the outq.
555 	 */
556 	if (cmd == TIOCEXT) {
557 		/*
558 		 * When the EXTPROC bit is being toggled, we need
559 		 * to send an TIOCPKT_IOCTL if the packet driver
560 		 * is turned on.
561 		 */
562 		if (*(int *)data) {
563 			if (pti->pt_flags & PF_PKT) {
564 				pti->pt_send |= TIOCPKT_IOCTL;
565 				ptcwakeup(tp, FREAD);
566 			}
567 			tp->t_lflag |= EXTPROC;
568 		} else {
569 			if ((tp->t_state & EXTPROC) &&
570 			    (pti->pt_flags & PF_PKT)) {
571 				pti->pt_send |= TIOCPKT_IOCTL;
572 				ptcwakeup(tp, FREAD);
573 			}
574 			tp->t_lflag &= ~EXTPROC;
575 		}
576 		return(0);
577 	} else
578 	if (cdevsw[major(dev)].d_open == ptcopen)
579 		switch (cmd) {
580 
581 		case TIOCGPGRP:
582 			/*
583 			 * We aviod calling ttioctl on the controller since,
584 			 * in that case, tp must be the controlling terminal.
585 			 */
586 			*(int *)data = tp->t_pgrp ? tp->t_pgrp->pg_id : 0;
587 			return (0);
588 
589 		case TIOCPKT:
590 			if (*(int *)data) {
591 				if (pti->pt_flags & PF_UCNTL)
592 					return (EINVAL);
593 				pti->pt_flags |= PF_PKT;
594 			} else
595 				pti->pt_flags &= ~PF_PKT;
596 			return (0);
597 
598 		case TIOCUCNTL:
599 			if (*(int *)data) {
600 				if (pti->pt_flags & PF_PKT)
601 					return (EINVAL);
602 				pti->pt_flags |= PF_UCNTL;
603 			} else
604 				pti->pt_flags &= ~PF_UCNTL;
605 			return (0);
606 
607 		case TIOCREMOTE:
608 			if (*(int *)data)
609 				pti->pt_flags |= PF_REMOTE;
610 			else
611 				pti->pt_flags &= ~PF_REMOTE;
612 			ttyflush(tp, FREAD|FWRITE);
613 			return (0);
614 
615 #ifdef COMPAT_43
616 		case TIOCSETP:
617 		case TIOCSETN:
618 #endif
619 		case TIOCSETD:
620 		case TIOCSETA:
621 		case TIOCSETAW:
622 		case TIOCSETAF:
623 			ndflush(&tp->t_outq, tp->t_outq.c_cc);
624 			break;
625 
626 		case TIOCSIG:
627 			if (*(unsigned int *)data >= NSIG)
628 				return(EINVAL);
629 			if ((tp->t_lflag&NOFLSH) == 0)
630 				ttyflush(tp, FREAD|FWRITE);
631 			pgsignal(tp->t_pgrp, *(unsigned int *)data, 1);
632 			if ((*(unsigned int *)data == SIGINFO) &&
633 			    ((tp->t_lflag&NOKERNINFO) == 0))
634 				ttyinfo(tp);
635 			return(0);
636 		}
637 	error = (*linesw[tp->t_line].l_ioctl)(tp, cmd, data, flag, p);
638 	if (error < 0)
639 		 error = ttioctl(tp, cmd, data, flag, p);
640 	if (error < 0) {
641 		if (pti->pt_flags & PF_UCNTL &&
642 		    (cmd & ~0xff) == UIOCCMD(0)) {
643 			if (cmd & 0xff) {
644 				pti->pt_ucntl = (u_char)cmd;
645 				ptcwakeup(tp, FREAD);
646 			}
647 			return (0);
648 		}
649 		error = ENOTTY;
650 	}
651 	/*
652 	 * If external processing and packet mode send ioctl packet.
653 	 */
654 	if ((tp->t_lflag&EXTPROC) && (pti->pt_flags & PF_PKT)) {
655 		switch(cmd) {
656 		case TIOCSETA:
657 		case TIOCSETAW:
658 		case TIOCSETAF:
659 #ifdef COMPAT_43
660 		case TIOCSETP:
661 		case TIOCSETN:
662 #endif
663 #if defined(COMPAT_43) || defined(COMPAT_SUNOS)
664 		case TIOCSETC:
665 		case TIOCSLTC:
666 		case TIOCLBIS:
667 		case TIOCLBIC:
668 		case TIOCLSET:
669 #endif
670 			pti->pt_send |= TIOCPKT_IOCTL;
671 			ptcwakeup(tp, FREAD);
672 		default:
673 			break;
674 		}
675 	}
676 	stop = (tp->t_iflag & IXON) && CCEQ(cc[VSTOP], CTRL('s'))
677 		&& CCEQ(cc[VSTART], CTRL('q'));
678 	if (pti->pt_flags & PF_NOSTOP) {
679 		if (stop) {
680 			pti->pt_send &= ~TIOCPKT_NOSTOP;
681 			pti->pt_send |= TIOCPKT_DOSTOP;
682 			pti->pt_flags &= ~PF_NOSTOP;
683 			ptcwakeup(tp, FREAD);
684 		}
685 	} else {
686 		if (!stop) {
687 			pti->pt_send &= ~TIOCPKT_DOSTOP;
688 			pti->pt_send |= TIOCPKT_NOSTOP;
689 			pti->pt_flags |= PF_NOSTOP;
690 			ptcwakeup(tp, FREAD);
691 		}
692 	}
693 	return (error);
694 }
695