xref: /netbsd/sys/kern/tty_pty.c (revision bf9ec67e)
1 /*	$NetBSD: tty_pty.c,v 1.62 2002/03/25 04:26:43 itohy Exp $	*/
2 
3 /*
4  * Copyright (c) 1982, 1986, 1989, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. All advertising materials mentioning features or use of this software
16  *    must display the following acknowledgement:
17  *	This product includes software developed by the University of
18  *	California, Berkeley and its contributors.
19  * 4. Neither the name of the University nor the names of its contributors
20  *    may be used to endorse or promote products derived from this software
21  *    without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  *
35  *	@(#)tty_pty.c	8.4 (Berkeley) 2/20/95
36  */
37 
38 /*
39  * Pseudo-teletype Driver
40  * (Actually two drivers, requiring two entries in 'cdevsw')
41  */
42 
43 #include <sys/cdefs.h>
44 __KERNEL_RCSID(0, "$NetBSD: tty_pty.c,v 1.62 2002/03/25 04:26:43 itohy Exp $");
45 
46 #include "opt_compat_sunos.h"
47 
48 #include <sys/param.h>
49 #include <sys/systm.h>
50 #include <sys/ioctl.h>
51 #include <sys/proc.h>
52 #include <sys/tty.h>
53 #include <sys/file.h>
54 #include <sys/uio.h>
55 #include <sys/kernel.h>
56 #include <sys/vnode.h>
57 #include <sys/signalvar.h>
58 #include <sys/uio.h>
59 #include <sys/conf.h>
60 #include <sys/poll.h>
61 #include <sys/malloc.h>
62 
63 #define	DEFAULT_NPTYS		16	/* default number of initial ptys */
64 #define DEFAULT_MAXPTYS		992	/* default maximum number of ptys */
65 
66 /* Macros to clear/set/test flags. */
67 #define	SET(t, f)	(t) |= (f)
68 #define	CLR(t, f)	(t) &= ~((unsigned)(f))
69 #define	ISSET(t, f)	((t) & (f))
70 
71 #define BUFSIZ 100		/* Chunk size iomoved to/from user */
72 
73 /*
74  * pts == /dev/tty[pqrs]?
75  * ptc == /dev/pty[pqrs]?
76  */
77 struct	pt_softc {
78 	struct	tty *pt_tty;
79 	int	pt_flags;
80 	struct	selinfo pt_selr, pt_selw;
81 	u_char	pt_send;
82 	u_char	pt_ucntl;
83 };
84 
85 static struct pt_softc **pt_softc = NULL;	/* pty array */
86 static int npty = 0;			/* for pstat -t */
87 static int maxptys = DEFAULT_MAXPTYS;	/* maximum number of ptys (sysctable) */
88 static struct simplelock pt_softc_mutex = SIMPLELOCK_INITIALIZER;
89 
90 #define	PF_PKT		0x08		/* packet mode */
91 #define	PF_STOPPED	0x10		/* user told stopped */
92 #define	PF_REMOTE	0x20		/* remote and flow controlled input */
93 #define	PF_NOSTOP	0x40
94 #define PF_UCNTL	0x80		/* user control mode */
95 
96 void	ptyattach __P((int));
97 void	ptcwakeup __P((struct tty *, int));
98 int	ptcopen __P((dev_t, int, int, struct proc *));
99 struct tty *ptytty __P((dev_t));
100 void	ptsstart __P((struct tty *));
101 int	pty_maxptys __P((int, int));
102 
103 static struct pt_softc **ptyarralloc __P((int));
104 static int check_pty __P((dev_t));
105 
106 /*
107  * Allocate and zero array of nelem elements.
108  */
109 static struct pt_softc **
110 ptyarralloc(nelem)
111 	int nelem;
112 {
113 	struct pt_softc **pt;
114 	nelem += 10;
115 	pt = malloc(nelem * sizeof(struct pt_softc *), M_DEVBUF, M_WAITOK);
116 	memset(pt, '\0', nelem * sizeof(struct pt_softc *));
117 	return pt;
118 }
119 
120 /*
121  * Check if the minor is correct and ensure necessary structures
122  * are properly allocated.
123  */
124 static int
125 check_pty(dev)
126 	dev_t dev;
127 {
128 	struct pt_softc *pti;
129 
130 	if (minor(dev) >= npty) {
131 		struct pt_softc **newpt;
132 		int newnpty;
133 
134 		/* check if the requested pty can be granted */
135 		if (minor(dev) >= maxptys) {
136 	    limit_reached:
137 			tablefull("pty", "increase kern.maxptys");
138 			return (ENXIO);
139 		}
140 
141 		/*
142 		 * Now grab the pty array mutex - we need to ensure
143 		 * that the pty array is consistent while copying it's
144 		 * content to newly allocated, larger space; we also
145 		 * need to be safe against pty_maxptys().
146 		 */
147 		simple_lock(&pt_softc_mutex);
148 
149 		do {
150 			for(newnpty = npty; newnpty <= minor(dev);
151 				newnpty *= 2);
152 
153 			if (newnpty > maxptys)
154 				newnpty = maxptys;
155 
156 			simple_unlock(&pt_softc_mutex);
157 			newpt = ptyarralloc(newnpty);
158 			simple_lock(&pt_softc_mutex);
159 
160 			if (maxptys == npty) {
161 				simple_unlock(&pt_softc_mutex);
162 				goto limit_reached;
163 			}
164 		} while(newnpty > maxptys);
165 
166 		/*
167 		 * If the pty array was not enlarged while we were waiting
168 		 * for mutex, copy current contents of pt_softc[] to newly
169 		 * allocated array and start using the new bigger array.
170 		 */
171 		if (minor(dev) >= npty) {
172 			memcpy(newpt, pt_softc, npty*sizeof(struct pt_softc *));
173 			free(pt_softc, M_DEVBUF);
174 
175 			pt_softc = newpt;
176 			npty = newnpty;
177 		} else {
178 			/* was enlarged when waited fot lock, free new space */
179 			free(newpt, M_DEVBUF);
180 		}
181 
182 		simple_unlock(&pt_softc_mutex);
183 	}
184 
185 	/*
186 	 * If the entry is not yet allocated, allocate one. The mutex is
187 	 * needed so that the state of pt_softc[] array is consistant
188 	 * in case it has been longened above.
189 	 */
190 	if (!pt_softc[minor(dev)]) {
191 		MALLOC(pti, struct pt_softc *, sizeof(struct pt_softc),
192 			M_DEVBUF, M_WAITOK);
193 
194 	 	pti->pt_tty = ttymalloc();
195 
196 		simple_lock(&pt_softc_mutex);
197 
198 		/*
199 		 * Check the entry again - it might have been
200 		 * added while we were waiting for mutex.
201 		 */
202 		if (!pt_softc[minor(dev)]) {
203 			tty_attach(pti->pt_tty);
204 			pt_softc[minor(dev)] = pti;
205 		} else {
206 			ttyfree(pti->pt_tty);
207 			FREE(pti, M_DEVBUF);
208 		}
209 
210 		simple_unlock(&pt_softc_mutex);
211 	}
212 
213 	return (0);
214 }
215 
216 /*
217  * Set maxpty in thread-safe way. Returns 0 in case of error, otherwise
218  * new value of maxptys.
219  */
220 int
221 pty_maxptys(newmax, set)
222 	int newmax, set;
223 {
224 	if (!set)
225 		return (maxptys);
226 
227 	/* the value cannot be set to value lower than current number of ptys */
228 	if (newmax < npty)
229 		return (0);
230 
231 	/* can proceed immediatelly if bigger than current maximum */
232 	if (newmax > maxptys) {
233 		maxptys = newmax;
234 		return (maxptys);
235 	}
236 
237 	/*
238 	 * We have to grab the pt_softc lock, so that we would pick correct
239 	 * value of npty (might be modified in check_pty()).
240 	 */
241 	simple_lock(&pt_softc_mutex);
242 
243 	if (newmax > npty)
244 		maxptys = newmax;
245 
246 	simple_unlock(&pt_softc_mutex);
247 
248 	return (maxptys);
249 }
250 
251 /*
252  * Establish n (or default if n is 1) ptys in the system.
253  */
254 void
255 ptyattach(n)
256 	int n;
257 {
258 	/* maybe should allow 0 => none? */
259 	if (n <= 1)
260 		n = DEFAULT_NPTYS;
261 	pt_softc = ptyarralloc(n);
262 	npty = n;
263 }
264 
265 /*ARGSUSED*/
266 int
267 ptsopen(dev, flag, devtype, p)
268 	dev_t dev;
269 	int flag, devtype;
270 	struct proc *p;
271 {
272 	struct pt_softc *pti;
273 	struct tty *tp;
274 	int error;
275 
276 	if ((error = check_pty(dev)))
277 		return (error);
278 
279 	pti = pt_softc[minor(dev)];
280 	tp = pti->pt_tty;
281 
282 	if (!ISSET(tp->t_state, TS_ISOPEN)) {
283 		ttychars(tp);		/* Set up default chars */
284 		tp->t_iflag = TTYDEF_IFLAG;
285 		tp->t_oflag = TTYDEF_OFLAG;
286 		tp->t_lflag = TTYDEF_LFLAG;
287 		tp->t_cflag = TTYDEF_CFLAG;
288 		tp->t_ispeed = tp->t_ospeed = TTYDEF_SPEED;
289 		ttsetwater(tp);		/* would be done in xxparam() */
290 	} else if (ISSET(tp->t_state, TS_XCLUDE) && p->p_ucred->cr_uid != 0)
291 		return (EBUSY);
292 	if (tp->t_oproc)			/* Ctrlr still around. */
293 		SET(tp->t_state, TS_CARR_ON);
294 	if (!ISSET(flag, O_NONBLOCK))
295 		while (!ISSET(tp->t_state, TS_CARR_ON)) {
296 			tp->t_wopen++;
297 			error = ttysleep(tp, &tp->t_rawq, TTIPRI | PCATCH,
298 			    ttopen, 0);
299 			tp->t_wopen--;
300 			if (error)
301 				return (error);
302 		}
303 	error = (*tp->t_linesw->l_open)(dev, tp);
304 	ptcwakeup(tp, FREAD|FWRITE);
305 	return (error);
306 }
307 
308 int
309 ptsclose(dev, flag, mode, p)
310 	dev_t dev;
311 	int flag, mode;
312 	struct proc *p;
313 {
314 	struct pt_softc *pti = pt_softc[minor(dev)];
315 	struct tty *tp = pti->pt_tty;
316 	int error;
317 
318 	error = (*tp->t_linesw->l_close)(tp, flag);
319 	error |= ttyclose(tp);
320 	ptcwakeup(tp, FREAD|FWRITE);
321 	return (error);
322 }
323 
324 int
325 ptsread(dev, uio, flag)
326 	dev_t dev;
327 	struct uio *uio;
328 	int flag;
329 {
330 	struct proc *p = curproc;
331 	struct pt_softc *pti = pt_softc[minor(dev)];
332 	struct tty *tp = pti->pt_tty;
333 	int error = 0;
334 
335 again:
336 	if (pti->pt_flags & PF_REMOTE) {
337 		while (isbackground(p, tp)) {
338 			if (sigismasked(p, SIGTTIN) ||
339 			    p->p_pgrp->pg_jobc == 0 ||
340 			    p->p_flag & P_PPWAIT)
341 				return (EIO);
342 			pgsignal(p->p_pgrp, SIGTTIN, 1);
343 			error = ttysleep(tp, (caddr_t)&lbolt,
344 					 TTIPRI | PCATCH, ttybg, 0);
345 			if (error)
346 				return (error);
347 		}
348 		if (tp->t_canq.c_cc == 0) {
349 			if (flag & IO_NDELAY)
350 				return (EWOULDBLOCK);
351 			error = ttysleep(tp, (caddr_t)&tp->t_canq,
352 					 TTIPRI | PCATCH, ttyin, 0);
353 			if (error)
354 				return (error);
355 			goto again;
356 		}
357 		while (tp->t_canq.c_cc > 1 && uio->uio_resid > 0)
358 			if (ureadc(getc(&tp->t_canq), uio) < 0) {
359 				error = EFAULT;
360 				break;
361 			}
362 		if (tp->t_canq.c_cc == 1)
363 			(void) getc(&tp->t_canq);
364 		if (tp->t_canq.c_cc)
365 			return (error);
366 	} else
367 		if (tp->t_oproc)
368 			error = (*tp->t_linesw->l_read)(tp, uio, flag);
369 	ptcwakeup(tp, FWRITE);
370 	return (error);
371 }
372 
373 /*
374  * Write to pseudo-tty.
375  * Wakeups of controlling tty will happen
376  * indirectly, when tty driver calls ptsstart.
377  */
378 int
379 ptswrite(dev, uio, flag)
380 	dev_t dev;
381 	struct uio *uio;
382 	int flag;
383 {
384 	struct pt_softc *pti = pt_softc[minor(dev)];
385 	struct tty *tp = pti->pt_tty;
386 
387 	if (tp->t_oproc == 0)
388 		return (EIO);
389 	return ((*tp->t_linesw->l_write)(tp, uio, flag));
390 }
391 
392 /*
393  * Poll pseudo-tty.
394  */
395 int
396 ptspoll(dev, events, p)
397 	dev_t dev;
398 	int events;
399 	struct proc *p;
400 {
401 	struct pt_softc *pti = pt_softc[minor(dev)];
402 	struct tty *tp = pti->pt_tty;
403 
404 	if (tp->t_oproc == 0)
405 		return (EIO);
406 
407 	return ((*tp->t_linesw->l_poll)(tp, events, p));
408 }
409 
410 /*
411  * Start output on pseudo-tty.
412  * Wake up process polling or sleeping for input from controlling tty.
413  */
414 void
415 ptsstart(tp)
416 	struct tty *tp;
417 {
418 	struct pt_softc *pti = pt_softc[minor(tp->t_dev)];
419 
420 	if (ISSET(tp->t_state, TS_TTSTOP))
421 		return;
422 	if (pti->pt_flags & PF_STOPPED) {
423 		pti->pt_flags &= ~PF_STOPPED;
424 		pti->pt_send = TIOCPKT_START;
425 	}
426 	ptcwakeup(tp, FREAD);
427 }
428 
429 void
430 ptsstop(tp, flush)
431 	struct tty *tp;
432 	int flush;
433 {
434 	struct pt_softc *pti = pt_softc[minor(tp->t_dev)];
435 	int flag;
436 
437 	/* note: FLUSHREAD and FLUSHWRITE already ok */
438 	if (flush == 0) {
439 		flush = TIOCPKT_STOP;
440 		pti->pt_flags |= PF_STOPPED;
441 	} else
442 		pti->pt_flags &= ~PF_STOPPED;
443 	pti->pt_send |= flush;
444 	/* change of perspective */
445 	flag = 0;
446 	if (flush & FREAD)
447 		flag |= FWRITE;
448 	if (flush & FWRITE)
449 		flag |= FREAD;
450 	ptcwakeup(tp, flag);
451 }
452 
453 void
454 ptcwakeup(tp, flag)
455 	struct tty *tp;
456 	int flag;
457 {
458 	struct pt_softc *pti = pt_softc[minor(tp->t_dev)];
459 
460 	if (flag & FREAD) {
461 		selwakeup(&pti->pt_selr);
462 		wakeup((caddr_t)&tp->t_outq.c_cf);
463 	}
464 	if (flag & FWRITE) {
465 		selwakeup(&pti->pt_selw);
466 		wakeup((caddr_t)&tp->t_rawq.c_cf);
467 	}
468 }
469 
470 /*ARGSUSED*/
471 int
472 ptcopen(dev, flag, devtype, p)
473 	dev_t dev;
474 	int flag, devtype;
475 	struct proc *p;
476 {
477 	struct pt_softc *pti;
478 	struct tty *tp;
479 	int error;
480 
481 	if ((error = check_pty(dev)))
482 		return (error);
483 
484 	pti = pt_softc[minor(dev)];
485 	tp = pti->pt_tty;
486 
487 	if (tp->t_oproc)
488 		return (EIO);
489 	tp->t_oproc = ptsstart;
490 	(void)(*tp->t_linesw->l_modem)(tp, 1);
491 	CLR(tp->t_lflag, EXTPROC);
492 	pti->pt_flags = 0;
493 	pti->pt_send = 0;
494 	pti->pt_ucntl = 0;
495 	return (0);
496 }
497 
498 /*ARGSUSED*/
499 int
500 ptcclose(dev, flag, devtype, p)
501 	dev_t dev;
502 	int flag, devtype;
503 	struct proc *p;
504 {
505 	struct pt_softc *pti = pt_softc[minor(dev)];
506 	struct tty *tp = pti->pt_tty;
507 
508 	(void)(*tp->t_linesw->l_modem)(tp, 0);
509 	CLR(tp->t_state, TS_CARR_ON);
510 	tp->t_oproc = 0;		/* mark closed */
511 	return (0);
512 }
513 
514 int
515 ptcread(dev, uio, flag)
516 	dev_t dev;
517 	struct uio *uio;
518 	int flag;
519 {
520 	struct pt_softc *pti = pt_softc[minor(dev)];
521 	struct tty *tp = pti->pt_tty;
522 	char buf[BUFSIZ];
523 	int error = 0, cc;
524 
525 	/*
526 	 * We want to block until the slave
527 	 * is open, and there's something to read;
528 	 * but if we lost the slave or we're NBIO,
529 	 * then return the appropriate error instead.
530 	 */
531 	for (;;) {
532 		if (ISSET(tp->t_state, TS_ISOPEN)) {
533 			if (pti->pt_flags&PF_PKT && pti->pt_send) {
534 				error = ureadc((int)pti->pt_send, uio);
535 				if (error)
536 					return (error);
537 				if (pti->pt_send & TIOCPKT_IOCTL) {
538 					cc = min(uio->uio_resid,
539 						sizeof(tp->t_termios));
540 					uiomove((caddr_t) &tp->t_termios,
541 						cc, uio);
542 				}
543 				pti->pt_send = 0;
544 				return (0);
545 			}
546 			if (pti->pt_flags&PF_UCNTL && pti->pt_ucntl) {
547 				error = ureadc((int)pti->pt_ucntl, uio);
548 				if (error)
549 					return (error);
550 				pti->pt_ucntl = 0;
551 				return (0);
552 			}
553 			if (tp->t_outq.c_cc && !ISSET(tp->t_state, TS_TTSTOP))
554 				break;
555 		}
556 		if (!ISSET(tp->t_state, TS_CARR_ON))
557 			return (0);	/* EOF */
558 		if (flag & IO_NDELAY)
559 			return (EWOULDBLOCK);
560 		error = tsleep((caddr_t)&tp->t_outq.c_cf, TTIPRI | PCATCH,
561 			       ttyin, 0);
562 		if (error)
563 			return (error);
564 	}
565 	if (pti->pt_flags & (PF_PKT|PF_UCNTL))
566 		error = ureadc(0, uio);
567 	while (uio->uio_resid > 0 && error == 0) {
568 		cc = q_to_b(&tp->t_outq, buf, min(uio->uio_resid, BUFSIZ));
569 		if (cc <= 0)
570 			break;
571 		error = uiomove(buf, cc, uio);
572 	}
573 	if (tp->t_outq.c_cc <= tp->t_lowat) {
574 		if (ISSET(tp->t_state, TS_ASLEEP)) {
575 			CLR(tp->t_state, TS_ASLEEP);
576 			wakeup((caddr_t)&tp->t_outq);
577 		}
578 		selwakeup(&tp->t_wsel);
579 	}
580 	return (error);
581 }
582 
583 
584 int
585 ptcwrite(dev, uio, flag)
586 	dev_t dev;
587 	struct uio *uio;
588 	int flag;
589 {
590 	struct pt_softc *pti = pt_softc[minor(dev)];
591 	struct tty *tp = pti->pt_tty;
592 	u_char *cp = NULL;
593 	int cc = 0;
594 	u_char locbuf[BUFSIZ];
595 	int cnt = 0;
596 	int error = 0;
597 
598 again:
599 	if (!ISSET(tp->t_state, TS_ISOPEN))
600 		goto block;
601 	if (pti->pt_flags & PF_REMOTE) {
602 		if (tp->t_canq.c_cc)
603 			goto block;
604 		while (uio->uio_resid > 0 && tp->t_canq.c_cc < TTYHOG - 1) {
605 			if (cc == 0) {
606 				cc = min(uio->uio_resid, BUFSIZ);
607 				cc = min(cc, TTYHOG - 1 - tp->t_canq.c_cc);
608 				cp = locbuf;
609 				error = uiomove((caddr_t)cp, cc, uio);
610 				if (error)
611 					return (error);
612 				/* check again for safety */
613 				if (!ISSET(tp->t_state, TS_ISOPEN))
614 					return (EIO);
615 			}
616 			if (cc)
617 				(void) b_to_q((char *)cp, cc, &tp->t_canq);
618 			cc = 0;
619 		}
620 		(void) putc(0, &tp->t_canq);
621 		ttwakeup(tp);
622 		wakeup((caddr_t)&tp->t_canq);
623 		return (0);
624 	}
625 	while (uio->uio_resid > 0) {
626 		if (cc == 0) {
627 			cc = min(uio->uio_resid, BUFSIZ);
628 			cp = locbuf;
629 			error = uiomove((caddr_t)cp, cc, uio);
630 			if (error)
631 				return (error);
632 			/* check again for safety */
633 			if (!ISSET(tp->t_state, TS_ISOPEN))
634 				return (EIO);
635 		}
636 		while (cc > 0) {
637 			if ((tp->t_rawq.c_cc + tp->t_canq.c_cc) >= TTYHOG - 2 &&
638 			   (tp->t_canq.c_cc > 0 || !ISSET(tp->t_lflag, ICANON))) {
639 				wakeup((caddr_t)&tp->t_rawq);
640 				goto block;
641 			}
642 			(*tp->t_linesw->l_rint)(*cp++, tp);
643 			cnt++;
644 			cc--;
645 		}
646 		cc = 0;
647 	}
648 	return (0);
649 block:
650 	/*
651 	 * Come here to wait for slave to open, for space
652 	 * in outq, or space in rawq.
653 	 */
654 	if (!ISSET(tp->t_state, TS_CARR_ON))
655 		return (EIO);
656 	if (flag & IO_NDELAY) {
657 		/* adjust for data copied in but not written */
658 		uio->uio_resid += cc;
659 		if (cnt == 0)
660 			return (EWOULDBLOCK);
661 		return (0);
662 	}
663 	error = tsleep((caddr_t)&tp->t_rawq.c_cf, TTOPRI | PCATCH,
664 		       ttyout, 0);
665 	if (error) {
666 		/* adjust for data copied in but not written */
667 		uio->uio_resid += cc;
668 		return (error);
669 	}
670 	goto again;
671 }
672 
673 int
674 ptcpoll(dev, events, p)
675 	dev_t dev;
676 	int events;
677 	struct proc *p;
678 {
679 	struct pt_softc *pti = pt_softc[minor(dev)];
680 	struct tty *tp = pti->pt_tty;
681 	int revents = 0;
682 	int s = splsoftclock();
683 
684 	if (events & (POLLIN | POLLRDNORM))
685 		if (ISSET(tp->t_state, TS_ISOPEN) &&
686 		    ((tp->t_outq.c_cc > 0 && !ISSET(tp->t_state, TS_TTSTOP)) ||
687 		     ((pti->pt_flags & PF_PKT) && pti->pt_send) ||
688 		     ((pti->pt_flags & PF_UCNTL) && pti->pt_ucntl)))
689 			revents |= events & (POLLIN | POLLRDNORM);
690 
691 	if (events & (POLLOUT | POLLWRNORM))
692 		if (ISSET(tp->t_state, TS_ISOPEN) &&
693 		    ((pti->pt_flags & PF_REMOTE) ?
694 		     (tp->t_canq.c_cc == 0) :
695 		     ((tp->t_rawq.c_cc + tp->t_canq.c_cc < TTYHOG-2) ||
696 		      (tp->t_canq.c_cc == 0 && ISSET(tp->t_lflag, ICANON)))))
697 			revents |= events & (POLLOUT | POLLWRNORM);
698 
699 	if (events & POLLHUP)
700 		if (!ISSET(tp->t_state, TS_CARR_ON))
701 			revents |= POLLHUP;
702 
703 	if (revents == 0) {
704 		if (events & (POLLIN | POLLHUP | POLLRDNORM))
705 			selrecord(p, &pti->pt_selr);
706 
707 		if (events & (POLLOUT | POLLWRNORM))
708 			selrecord(p, &pti->pt_selw);
709 	}
710 
711 	splx(s);
712 	return (revents);
713 }
714 
715 
716 struct tty *
717 ptytty(dev)
718 	dev_t dev;
719 {
720 	struct pt_softc *pti = pt_softc[minor(dev)];
721 	struct tty *tp = pti->pt_tty;
722 
723 	return (tp);
724 }
725 
726 /*ARGSUSED*/
727 int
728 ptyioctl(dev, cmd, data, flag, p)
729 	dev_t dev;
730 	u_long cmd;
731 	caddr_t data;
732 	int flag;
733 	struct proc *p;
734 {
735 	struct pt_softc *pti = pt_softc[minor(dev)];
736 	struct tty *tp = pti->pt_tty;
737 	u_char *cc = tp->t_cc;
738 	int stop, error, sig;
739 
740 	/*
741 	 * IF CONTROLLER STTY THEN MUST FLUSH TO PREVENT A HANG.
742 	 * ttywflush(tp) will hang if there are characters in the outq.
743 	 */
744 	if (cmd == TIOCEXT) {
745 		/*
746 		 * When the EXTPROC bit is being toggled, we need
747 		 * to send an TIOCPKT_IOCTL if the packet driver
748 		 * is turned on.
749 		 */
750 		if (*(int *)data) {
751 			if (pti->pt_flags & PF_PKT) {
752 				pti->pt_send |= TIOCPKT_IOCTL;
753 				ptcwakeup(tp, FREAD);
754 			}
755 			SET(tp->t_lflag, EXTPROC);
756 		} else {
757 			if (ISSET(tp->t_lflag, EXTPROC) &&
758 			    (pti->pt_flags & PF_PKT)) {
759 				pti->pt_send |= TIOCPKT_IOCTL;
760 				ptcwakeup(tp, FREAD);
761 			}
762 			CLR(tp->t_lflag, EXTPROC);
763 		}
764 		return(0);
765 	} else
766 	if (cdevsw[major(dev)].d_open == ptcopen)
767 		switch (cmd) {
768 
769 		case TIOCGPGRP:
770 			/*
771 			 * We avoid calling ttioctl on the controller since,
772 			 * in that case, tp must be the controlling terminal.
773 			 */
774 			*(int *)data = tp->t_pgrp ? tp->t_pgrp->pg_id : 0;
775 			return (0);
776 
777 		case TIOCPKT:
778 			if (*(int *)data) {
779 				if (pti->pt_flags & PF_UCNTL)
780 					return (EINVAL);
781 				pti->pt_flags |= PF_PKT;
782 			} else
783 				pti->pt_flags &= ~PF_PKT;
784 			return (0);
785 
786 		case TIOCUCNTL:
787 			if (*(int *)data) {
788 				if (pti->pt_flags & PF_PKT)
789 					return (EINVAL);
790 				pti->pt_flags |= PF_UCNTL;
791 			} else
792 				pti->pt_flags &= ~PF_UCNTL;
793 			return (0);
794 
795 		case TIOCREMOTE:
796 			if (*(int *)data)
797 				pti->pt_flags |= PF_REMOTE;
798 			else
799 				pti->pt_flags &= ~PF_REMOTE;
800 			ttyflush(tp, FREAD|FWRITE);
801 			return (0);
802 
803 #ifdef COMPAT_OLDTTY
804 		case TIOCSETP:
805 		case TIOCSETN:
806 #endif
807 		case TIOCSETD:
808 		case TIOCSETA:
809 		case TIOCSETAW:
810 		case TIOCSETAF:
811 			ndflush(&tp->t_outq, tp->t_outq.c_cc);
812 			break;
813 
814 		case TIOCSIG:
815 			sig = (int)(long)*(caddr_t *)data;
816 			if (sig <= 0 || sig >= NSIG)
817 				return (EINVAL);
818 			if (!ISSET(tp->t_lflag, NOFLSH))
819 				ttyflush(tp, FREAD|FWRITE);
820 			if ((sig == SIGINFO) &&
821 			    (!ISSET(tp->t_lflag, NOKERNINFO)))
822 				ttyinfo(tp);
823 			pgsignal(tp->t_pgrp, sig, 1);
824 			return(0);
825 		}
826 	error = (*tp->t_linesw->l_ioctl)(tp, cmd, data, flag, p);
827 	if (error == EPASSTHROUGH)
828 		 error = ttioctl(tp, cmd, data, flag, p);
829 	if (error == EPASSTHROUGH) {
830 		if (pti->pt_flags & PF_UCNTL &&
831 		    (cmd & ~0xff) == UIOCCMD(0)) {
832 			if (cmd & 0xff) {
833 				pti->pt_ucntl = (u_char)cmd;
834 				ptcwakeup(tp, FREAD);
835 			}
836 			return (0);
837 		}
838 	}
839 	/*
840 	 * If external processing and packet mode send ioctl packet.
841 	 */
842 	if (ISSET(tp->t_lflag, EXTPROC) && (pti->pt_flags & PF_PKT)) {
843 		switch(cmd) {
844 		case TIOCSETA:
845 		case TIOCSETAW:
846 		case TIOCSETAF:
847 #ifdef COMPAT_OLDTTY
848 		case TIOCSETP:
849 		case TIOCSETN:
850 		case TIOCSETC:
851 		case TIOCSLTC:
852 		case TIOCLBIS:
853 		case TIOCLBIC:
854 		case TIOCLSET:
855 #endif
856 			pti->pt_send |= TIOCPKT_IOCTL;
857 			ptcwakeup(tp, FREAD);
858 		default:
859 			break;
860 		}
861 	}
862 	stop = ISSET(tp->t_iflag, IXON) && CCEQ(cc[VSTOP], CTRL('s'))
863 		&& CCEQ(cc[VSTART], CTRL('q'));
864 	if (pti->pt_flags & PF_NOSTOP) {
865 		if (stop) {
866 			pti->pt_send &= ~TIOCPKT_NOSTOP;
867 			pti->pt_send |= TIOCPKT_DOSTOP;
868 			pti->pt_flags &= ~PF_NOSTOP;
869 			ptcwakeup(tp, FREAD);
870 		}
871 	} else {
872 		if (!stop) {
873 			pti->pt_send &= ~TIOCPKT_DOSTOP;
874 			pti->pt_send |= TIOCPKT_NOSTOP;
875 			pti->pt_flags |= PF_NOSTOP;
876 			ptcwakeup(tp, FREAD);
877 		}
878 	}
879 	return (error);
880 }
881