pty.c revision 9850 
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 *	@(#)tty_pty.c	8.2 (Berkeley) 9/23/93
34 * $Id: tty_pty.c,v 1.16 1995/07/31 21:01:25 bde 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#include <sys/signalvar.h>
54
55#if NPTY == 1
56#undef NPTY
57#define	NPTY	32		/* crude XXX */
58#endif
59
60#define BUFSIZ 100		/* Chunk size iomoved to/from user */
61
62/*
63 * pts == /dev/tty[pqrs]?
64 * ptc == /dev/pty[pqrs]?
65 */
66struct	tty pt_tty[NPTY];	/* XXX */
67struct	pt_ioctl {
68	int	pt_flags;
69	struct	selinfo pt_selr, pt_selw;
70	u_char	pt_send;
71	u_char	pt_ucntl;
72} pt_ioctl[NPTY];		/* XXX */
73int	npty = NPTY;		/* for pstat -t */
74
75#define	PF_PKT		0x08		/* packet mode */
76#define	PF_STOPPED	0x10		/* user told stopped */
77#define	PF_REMOTE	0x20		/* remote and flow controlled input */
78#define	PF_NOSTOP	0x40
79#define PF_UCNTL	0x80		/* user control mode */
80
81void	ptsstop		__P((struct tty *, int));
82void	ptcwakeup	__P((struct tty *, int));
83
84/*
85 * Establish n (or default if n is 1) ptys in the system.
86 *
87 * XXX cdevsw & pstat require the array `pty[]' to be an array
88 */
89void
90ptyattach(n)
91	int n;
92{
93#ifdef notyet
94	char *mem;
95	register u_long ntb;
96#define	DEFAULT_NPTY	32
97
98	/* maybe should allow 0 => none? */
99	if (n <= 1)
100		n = DEFAULT_NPTY;
101	ntb = n * sizeof(struct tty);
102	mem = malloc(ntb + ALIGNBYTES + n * sizeof(struct pt_ioctl),
103	    M_DEVBUF, M_WAITOK);
104	pt_tty = (struct tty *)mem;
105	mem = (char *)ALIGN(mem + ntb);
106	pt_ioctl = (struct pt_ioctl *)mem;
107	npty = n;
108#endif
109}
110
111/*ARGSUSED*/
112int
113ptsopen(dev, flag, devtype, p)
114	dev_t dev;
115	int flag, devtype;
116	struct proc *p;
117{
118	register struct tty *tp;
119	int error;
120
121	if (minor(dev) >= npty)
122		return (ENXIO);
123	tp = &pt_tty[minor(dev)];
124	if ((tp->t_state & TS_ISOPEN) == 0) {
125		ttychars(tp);		/* Set up default chars */
126		tp->t_iflag = TTYDEF_IFLAG;
127		tp->t_oflag = TTYDEF_OFLAG;
128		tp->t_lflag = TTYDEF_LFLAG;
129		tp->t_cflag = TTYDEF_CFLAG;
130		tp->t_ispeed = tp->t_ospeed = TTYDEF_SPEED;
131		ttsetwater(tp);		/* would be done in xxparam() */
132	} else if (tp->t_state&TS_XCLUDE && p->p_ucred->cr_uid != 0)
133		return (EBUSY);
134	if (tp->t_oproc)			/* Ctrlr still around. */
135		(void)(*linesw[tp->t_line].l_modem)(tp, 1);
136	while ((tp->t_state & TS_CARR_ON) == 0) {
137		if (flag&FNONBLOCK)
138			break;
139		error = ttysleep(tp, TSA_CARR_ON(tp), TTIPRI | PCATCH,
140				 "ptsopn", 0);
141		if (error)
142			return (error);
143	}
144	error = (*linesw[tp->t_line].l_open)(dev, tp);
145	if (error == 0)
146		ptcwakeup(tp, FREAD|FWRITE);
147	return (error);
148}
149
150int
151ptsclose(dev, flag, mode, p)
152	dev_t dev;
153	int flag, mode;
154	struct proc *p;
155{
156	register struct tty *tp;
157	int err;
158
159	tp = &pt_tty[minor(dev)];
160	err = (*linesw[tp->t_line].l_close)(tp, flag);
161	ptsstop(tp, FREAD|FWRITE);
162	(void) ttyclose(tp);
163	return (err);
164}
165
166int
167ptsread(dev, uio, flag)
168	dev_t dev;
169	struct uio *uio;
170	int flag;
171{
172	struct proc *p = curproc;
173	register struct tty *tp = &pt_tty[minor(dev)];
174	register struct pt_ioctl *pti = &pt_ioctl[minor(dev)];
175	int error = 0;
176
177again:
178	if (pti->pt_flags & PF_REMOTE) {
179		while (isbackground(p, tp)) {
180			if ((p->p_sigignore & sigmask(SIGTTIN)) ||
181			    (p->p_sigmask & sigmask(SIGTTIN)) ||
182			    p->p_pgrp->pg_jobc == 0 ||
183			    p->p_flag & P_PPWAIT)
184				return (EIO);
185			pgsignal(p->p_pgrp, SIGTTIN, 1);
186			error = ttysleep(tp, &lbolt, TTIPRI | PCATCH, "ptsbg",
187					 0);
188			if (error)
189				return (error);
190		}
191		if (tp->t_canq.c_cc == 0) {
192			if (flag & IO_NDELAY)
193				return (EWOULDBLOCK);
194			error = ttysleep(tp, TSA_PTS_READ(tp), TTIPRI | PCATCH,
195					 "ptsin", 0);
196			if (error)
197				return (error);
198			goto again;
199		}
200		while (tp->t_canq.c_cc > 1 && uio->uio_resid > 0)
201			if (ureadc(getc(&tp->t_canq), uio) < 0) {
202				error = EFAULT;
203				break;
204			}
205		if (tp->t_canq.c_cc == 1)
206			(void) getc(&tp->t_canq);
207		if (tp->t_canq.c_cc)
208			return (error);
209	} else
210		if (tp->t_oproc)
211			error = (*linesw[tp->t_line].l_read)(tp, uio, flag);
212	ptcwakeup(tp, FWRITE);
213	return (error);
214}
215
216/*
217 * Write to pseudo-tty.
218 * Wakeups of controlling tty will happen
219 * indirectly, when tty driver calls ptsstart.
220 */
221int
222ptswrite(dev, uio, flag)
223	dev_t dev;
224	struct uio *uio;
225	int flag;
226{
227	register struct tty *tp;
228
229	tp = &pt_tty[minor(dev)];
230	if (tp->t_oproc == 0)
231		return (EIO);
232	return ((*linesw[tp->t_line].l_write)(tp, uio, flag));
233}
234
235/*
236 * Start output on pseudo-tty.
237 * Wake up process selecting or sleeping for input from controlling tty.
238 */
239void
240ptsstart(tp)
241	struct tty *tp;
242{
243	register struct pt_ioctl *pti = &pt_ioctl[minor(tp->t_dev)];
244
245	if (tp->t_state & TS_TTSTOP)
246		return;
247	if (pti->pt_flags & PF_STOPPED) {
248		pti->pt_flags &= ~PF_STOPPED;
249		pti->pt_send = TIOCPKT_START;
250	}
251	ptcwakeup(tp, FREAD);
252}
253
254void
255ptcwakeup(tp, flag)
256	struct tty *tp;
257	int flag;
258{
259	struct pt_ioctl *pti = &pt_ioctl[minor(tp->t_dev)];
260
261	if (flag & FREAD) {
262		selwakeup(&pti->pt_selr);
263		wakeup(TSA_PTC_READ(tp));
264	}
265	if (flag & FWRITE) {
266		selwakeup(&pti->pt_selw);
267		wakeup(TSA_PTC_WRITE(tp));
268	}
269}
270
271int
272ptcopen(dev, flag, devtype, p)
273	dev_t dev;
274	int flag, devtype;
275	struct proc *p;
276{
277	register struct tty *tp;
278	struct pt_ioctl *pti;
279
280	if (minor(dev) >= npty)
281		return (ENXIO);
282	tp = &pt_tty[minor(dev)];
283	if (tp->t_oproc)
284		return (EIO);
285	tp->t_oproc = ptsstart;
286#ifdef sun4c
287	tp->t_stop = ptsstop;
288#endif
289	(void)(*linesw[tp->t_line].l_modem)(tp, 1);
290	tp->t_lflag &= ~EXTPROC;
291	pti = &pt_ioctl[minor(dev)];
292	pti->pt_flags = 0;
293	pti->pt_send = 0;
294	pti->pt_ucntl = 0;
295	return (0);
296}
297
298int
299ptcclose(dev)
300	dev_t dev;
301{
302	register struct tty *tp;
303
304	tp = &pt_tty[minor(dev)];
305	(void)(*linesw[tp->t_line].l_modem)(tp, 0);
306
307	/*
308	 * XXX MDMBUF makes no sense for ptys but would inhibit the above
309	 * l_modem().  CLOCAL makes sense but isn't supported.   Special
310	 * l_modem()s that ignore carrier drop make no sense for ptys but
311	 * may be in use because other parts of the line discipline make
312	 * sense for ptys.  Recover by doing everything that a normal
313	 * ttymodem() would have done except for sending a SIGHUP.
314	 */
315	if (tp->t_state & TS_ISOPEN) {
316		tp->t_state &= ~(TS_CARR_ON | TS_CONNECTED);
317		tp->t_state |= TS_ZOMBIE;
318		ttyflush(tp, FREAD | FWRITE);
319	}
320
321	tp->t_oproc = 0;		/* mark closed */
322	tp->t_session = 0;
323	return (0);
324}
325
326int
327ptcread(dev, uio, flag)
328	dev_t dev;
329	struct uio *uio;
330	int flag;
331{
332	register struct tty *tp = &pt_tty[minor(dev)];
333	struct pt_ioctl *pti = &pt_ioctl[minor(dev)];
334	char buf[BUFSIZ];
335	int error = 0, cc;
336
337	/*
338	 * We want to block until the slave
339	 * is open, and there's something to read;
340	 * but if we lost the slave or we're NBIO,
341	 * then return the appropriate error instead.
342	 */
343	for (;;) {
344		if (tp->t_state&TS_ISOPEN) {
345			if (pti->pt_flags&PF_PKT && pti->pt_send) {
346				error = ureadc((int)pti->pt_send, uio);
347				if (error)
348					return (error);
349				if (pti->pt_send & TIOCPKT_IOCTL) {
350					cc = min(uio->uio_resid,
351						sizeof(tp->t_termios));
352					uiomove((caddr_t)&tp->t_termios, cc,
353						uio);
354				}
355				pti->pt_send = 0;
356				return (0);
357			}
358			if (pti->pt_flags&PF_UCNTL && pti->pt_ucntl) {
359				error = ureadc((int)pti->pt_ucntl, uio);
360				if (error)
361					return (error);
362				pti->pt_ucntl = 0;
363				return (0);
364			}
365			if (tp->t_outq.c_cc && (tp->t_state&TS_TTSTOP) == 0)
366				break;
367		}
368		if ((tp->t_state & TS_CONNECTED) == 0)
369			return (0);	/* EOF */
370		if (flag & IO_NDELAY)
371			return (EWOULDBLOCK);
372		error = tsleep(TSA_PTC_READ(tp), TTIPRI | PCATCH, "ptcin", 0);
373		if (error)
374			return (error);
375	}
376	if (pti->pt_flags & (PF_PKT|PF_UCNTL))
377		error = ureadc(0, uio);
378	while (uio->uio_resid > 0 && error == 0) {
379		cc = q_to_b(&tp->t_outq, buf, min(uio->uio_resid, BUFSIZ));
380		if (cc <= 0)
381			break;
382		error = uiomove(buf, cc, uio);
383	}
384	ttwwakeup(tp);
385	return (error);
386}
387
388void
389ptsstop(tp, flush)
390	register struct tty *tp;
391	int flush;
392{
393	struct pt_ioctl *pti = &pt_ioctl[minor(tp->t_dev)];
394	int flag;
395
396	/* note: FLUSHREAD and FLUSHWRITE already ok */
397	if (flush == 0) {
398		flush = TIOCPKT_STOP;
399		pti->pt_flags |= PF_STOPPED;
400	} else
401		pti->pt_flags &= ~PF_STOPPED;
402	pti->pt_send |= flush;
403	/* change of perspective */
404	flag = 0;
405	if (flush & FREAD)
406		flag |= FWRITE;
407	if (flush & FWRITE)
408		flag |= FREAD;
409	ptcwakeup(tp, flag);
410}
411
412int
413ptcselect(dev, rw, p)
414	dev_t dev;
415	int rw;
416	struct proc *p;
417{
418	register struct tty *tp = &pt_tty[minor(dev)];
419	struct pt_ioctl *pti = &pt_ioctl[minor(dev)];
420	int s;
421
422	if ((tp->t_state & TS_CONNECTED) == 0)
423		return (1);
424	switch (rw) {
425
426	case FREAD:
427		/*
428		 * Need to block timeouts (ttrstart).
429		 */
430		s = spltty();
431		if ((tp->t_state&TS_ISOPEN) &&
432		     tp->t_outq.c_cc && (tp->t_state&TS_TTSTOP) == 0) {
433			splx(s);
434			return (1);
435		}
436		splx(s);
437		/* FALLTHROUGH */
438
439	case 0:					/* exceptional */
440		if ((tp->t_state&TS_ISOPEN) &&
441		    ((pti->pt_flags&PF_PKT && pti->pt_send) ||
442		     (pti->pt_flags&PF_UCNTL && pti->pt_ucntl)))
443			return (1);
444		selrecord(p, &pti->pt_selr);
445		break;
446
447
448	case FWRITE:
449		if (tp->t_state&TS_ISOPEN) {
450			if (pti->pt_flags & PF_REMOTE) {
451			    if (tp->t_canq.c_cc == 0)
452				return (1);
453			} else {
454			    if (tp->t_rawq.c_cc + tp->t_canq.c_cc < TTYHOG-2)
455				    return (1);
456			    if (tp->t_canq.c_cc == 0 && (tp->t_iflag&ICANON))
457				    return (1);
458			}
459		}
460		selrecord(p, &pti->pt_selw);
461		break;
462
463	}
464	return (0);
465}
466
467int
468ptcwrite(dev, uio, flag)
469	dev_t dev;
470	register struct uio *uio;
471	int flag;
472{
473	register struct tty *tp = &pt_tty[minor(dev)];
474	register u_char *cp = 0;
475	register int cc = 0;
476	u_char locbuf[BUFSIZ];
477	int cnt = 0;
478	struct pt_ioctl *pti = &pt_ioctl[minor(dev)];
479	int error = 0;
480
481again:
482	if ((tp->t_state&TS_ISOPEN) == 0)
483		goto block;
484	if (pti->pt_flags & PF_REMOTE) {
485		if (tp->t_canq.c_cc)
486			goto block;
487		while (uio->uio_resid > 0 && tp->t_canq.c_cc < TTYHOG - 1) {
488			if (cc == 0) {
489				cc = min(uio->uio_resid, BUFSIZ);
490				cc = min(cc, TTYHOG - 1 - tp->t_canq.c_cc);
491				cp = locbuf;
492				error = uiomove((caddr_t)cp, cc, uio);
493				if (error)
494					return (error);
495				/* check again for safety */
496				if ((tp->t_state&TS_ISOPEN) == 0)
497					return (EIO);
498			}
499			if (cc)
500				(void) b_to_q((char *)cp, cc, &tp->t_canq);
501			cc = 0;
502		}
503		(void) putc(0, &tp->t_canq);
504		ttwakeup(tp);
505		wakeup(TSA_PTS_READ(tp));
506		return (0);
507	}
508	while (uio->uio_resid > 0) {
509		if (cc == 0) {
510			cc = min(uio->uio_resid, BUFSIZ);
511			cp = locbuf;
512			error = uiomove((caddr_t)cp, cc, uio);
513			if (error)
514				return (error);
515			/* check again for safety */
516			if ((tp->t_state&TS_ISOPEN) == 0)
517				return (EIO);
518		}
519		while (cc > 0) {
520			if ((tp->t_rawq.c_cc + tp->t_canq.c_cc) >= TTYHOG - 2 &&
521			   (tp->t_canq.c_cc > 0 || !(tp->t_iflag&ICANON))) {
522				wakeup(TSA_HUP_OR_INPUT(tp));
523				goto block;
524			}
525			(*linesw[tp->t_line].l_rint)(*cp++, tp);
526			cnt++;
527			cc--;
528		}
529		cc = 0;
530	}
531	return (0);
532block:
533	/*
534	 * Come here to wait for slave to open, for space
535	 * in outq, or space in rawq.
536	 */
537	if ((tp->t_state & TS_CONNECTED) == 0)
538		return (EIO);
539	if (flag & IO_NDELAY) {
540		/* adjust for data copied in but not written */
541		uio->uio_resid += cc;
542		if (cnt == 0)
543			return (EWOULDBLOCK);
544		return (0);
545	}
546	error = tsleep(TSA_PTC_WRITE(tp), TTOPRI | PCATCH, "ptcout", 0);
547	if (error) {
548		/* adjust for data copied in but not written */
549		uio->uio_resid += cc;
550		return (error);
551	}
552	goto again;
553}
554
555struct tty *
556ptydevtotty(dev)
557	dev_t		dev;
558{
559	if (minor(dev) >= npty)
560		return (NULL);
561
562	return &pt_tty[minor(dev)];
563}
564
565/*ARGSUSED*/
566int
567ptyioctl(dev, cmd, data, flag, p)
568	dev_t dev;
569	int cmd;
570	caddr_t data;
571	int flag;
572	struct proc *p;
573{
574	register struct tty *tp = &pt_tty[minor(dev)];
575	register struct pt_ioctl *pti = &pt_ioctl[minor(dev)];
576	register u_char *cc = tp->t_cc;
577	int stop, error;
578
579	/*
580	 * IF CONTROLLER STTY THEN MUST FLUSH TO PREVENT A HANG.
581	 * ttywflush(tp) will hang if there are characters in the outq.
582	 */
583	if (cmd == TIOCEXT) {
584		/*
585		 * When the EXTPROC bit is being toggled, we need
586		 * to send an TIOCPKT_IOCTL if the packet driver
587		 * is turned on.
588		 */
589		if (*(int *)data) {
590			if (pti->pt_flags & PF_PKT) {
591				pti->pt_send |= TIOCPKT_IOCTL;
592				ptcwakeup(tp, FREAD);
593			}
594			tp->t_lflag |= EXTPROC;
595		} else {
596			if ((tp->t_state & EXTPROC) &&
597			    (pti->pt_flags & PF_PKT)) {
598				pti->pt_send |= TIOCPKT_IOCTL;
599				ptcwakeup(tp, FREAD);
600			}
601			tp->t_lflag &= ~EXTPROC;
602		}
603		return(0);
604	} else
605	if (cdevsw[major(dev)].d_open == ptcopen)
606		switch (cmd) {
607
608		case TIOCGPGRP:
609			/*
610			 * We aviod calling ttioctl on the controller since,
611			 * in that case, tp must be the controlling terminal.
612			 */
613			*(int *)data = tp->t_pgrp ? tp->t_pgrp->pg_id : 0;
614			return (0);
615
616		case TIOCPKT:
617			if (*(int *)data) {
618				if (pti->pt_flags & PF_UCNTL)
619					return (EINVAL);
620				pti->pt_flags |= PF_PKT;
621			} else
622				pti->pt_flags &= ~PF_PKT;
623			return (0);
624
625		case TIOCUCNTL:
626			if (*(int *)data) {
627				if (pti->pt_flags & PF_PKT)
628					return (EINVAL);
629				pti->pt_flags |= PF_UCNTL;
630			} else
631				pti->pt_flags &= ~PF_UCNTL;
632			return (0);
633
634		case TIOCREMOTE:
635			if (*(int *)data)
636				pti->pt_flags |= PF_REMOTE;
637			else
638				pti->pt_flags &= ~PF_REMOTE;
639			ttyflush(tp, FREAD|FWRITE);
640			return (0);
641
642#ifdef COMPAT_43
643		case TIOCSETP:
644		case TIOCSETN:
645#endif
646		case TIOCSETD:
647		case TIOCSETA:
648		case TIOCSETAW:
649		case TIOCSETAF:
650			ndflush(&tp->t_outq, tp->t_outq.c_cc);
651			break;
652
653		case TIOCSIG:
654			if (*(unsigned int *)data >= NSIG)
655				return(EINVAL);
656			if ((tp->t_lflag&NOFLSH) == 0)
657				ttyflush(tp, FREAD|FWRITE);
658			pgsignal(tp->t_pgrp, *(unsigned int *)data, 1);
659			if ((*(unsigned int *)data == SIGINFO) &&
660			    ((tp->t_lflag&NOKERNINFO) == 0))
661				ttyinfo(tp);
662			return(0);
663		}
664	error = (*linesw[tp->t_line].l_ioctl)(tp, cmd, data, flag, p);
665	if (error < 0)
666		 error = ttioctl(tp, cmd, data, flag);
667	if (error < 0) {
668		if (pti->pt_flags & PF_UCNTL &&
669		    (cmd & ~0xff) == UIOCCMD(0)) {
670			if (cmd & 0xff) {
671				pti->pt_ucntl = (u_char)cmd;
672				ptcwakeup(tp, FREAD);
673			}
674			return (0);
675		}
676		error = ENOTTY;
677	}
678	/*
679	 * If external processing and packet mode send ioctl packet.
680	 */
681	if ((tp->t_lflag&EXTPROC) && (pti->pt_flags & PF_PKT)) {
682		switch(cmd) {
683		case TIOCSETA:
684		case TIOCSETAW:
685		case TIOCSETAF:
686#ifdef COMPAT_43
687		case TIOCSETP:
688		case TIOCSETN:
689#endif
690#if defined(COMPAT_43) || defined(COMPAT_SUNOS)
691		case TIOCSETC:
692		case TIOCSLTC:
693		case TIOCLBIS:
694		case TIOCLBIC:
695		case TIOCLSET:
696#endif
697			pti->pt_send |= TIOCPKT_IOCTL;
698			ptcwakeup(tp, FREAD);
699		default:
700			break;
701		}
702	}
703	stop = (tp->t_iflag & IXON) && CCEQ(cc[VSTOP], CTRL('s'))
704		&& CCEQ(cc[VSTART], CTRL('q'));
705	if (pti->pt_flags & PF_NOSTOP) {
706		if (stop) {
707			pti->pt_send &= ~TIOCPKT_NOSTOP;
708			pti->pt_send |= TIOCPKT_DOSTOP;
709			pti->pt_flags &= ~PF_NOSTOP;
710			ptcwakeup(tp, FREAD);
711		}
712	} else {
713		if (!stop) {
714			pti->pt_send &= ~TIOCPKT_DOSTOP;
715			pti->pt_send |= TIOCPKT_NOSTOP;
716			pti->pt_flags |= PF_NOSTOP;
717			ptcwakeup(tp, FREAD);
718		}
719	}
720	return (error);
721}
722