xref: /netbsd-src/sys/kern/tty_pty.c (revision 3b01aba77a7a698587faaae455bbfe740923c1f5)
1 /*	$NetBSD: tty_pty.c,v 1.56 2001/05/02 10:32:08 scw 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 "opt_compat_sunos.h"
44 
45 #include <sys/param.h>
46 #include <sys/systm.h>
47 #include <sys/ioctl.h>
48 #include <sys/proc.h>
49 #include <sys/tty.h>
50 #include <sys/file.h>
51 #include <sys/uio.h>
52 #include <sys/kernel.h>
53 #include <sys/vnode.h>
54 #include <sys/signalvar.h>
55 #include <sys/uio.h>
56 #include <sys/conf.h>
57 #include <sys/poll.h>
58 #include <sys/malloc.h>
59 
60 #define	DEFAULT_NPTYS		16	/* default number of initial ptys */
61 #define DEFAULT_MAXPTYS		256	/* default maximum number of ptys */
62 
63 /* Macros to clear/set/test flags. */
64 #define	SET(t, f)	(t) |= (f)
65 #define	CLR(t, f)	(t) &= ~((unsigned)(f))
66 #define	ISSET(t, f)	((t) & (f))
67 
68 #define BUFSIZ 100		/* Chunk size iomoved to/from user */
69 
70 /*
71  * pts == /dev/tty[pqrs]?
72  * ptc == /dev/pty[pqrs]?
73  */
74 struct	pt_softc {
75 	struct	tty *pt_tty;
76 	int	pt_flags;
77 	struct	selinfo pt_selr, pt_selw;
78 	u_char	pt_send;
79 	u_char	pt_ucntl;
80 };
81 
82 static struct pt_softc **pt_softc = NULL;	/* pty array */
83 static int npty = 0;			/* for pstat -t */
84 static int maxptys = DEFAULT_MAXPTYS;	/* maximum number of ptys (sysctable) */
85 static struct simplelock pt_softc_mutex = SIMPLELOCK_INITIALIZER;
86 
87 #define	PF_PKT		0x08		/* packet mode */
88 #define	PF_STOPPED	0x10		/* user told stopped */
89 #define	PF_REMOTE	0x20		/* remote and flow controlled input */
90 #define	PF_NOSTOP	0x40
91 #define PF_UCNTL	0x80		/* user control mode */
92 
93 void	ptyattach __P((int));
94 void	ptcwakeup __P((struct tty *, int));
95 int	ptcopen __P((dev_t, int, int, struct proc *));
96 struct tty *ptytty __P((dev_t));
97 void	ptsstart __P((struct tty *));
98 int	pty_maxptys __P((int, int));
99 
100 static struct pt_softc **ptyarralloc __P((int));
101 static int check_pty __P((dev_t));
102 
103 /*
104  * Allocate and zero array of nelem elements.
105  */
106 static struct pt_softc **
107 ptyarralloc(nelem)
108 	int nelem;
109 {
110 	struct pt_softc **pt;
111 	nelem += 10;
112 	pt = malloc(nelem * sizeof(struct pt_softc *), M_DEVBUF, M_WAITOK);
113 	memset(pt, '\0', nelem * sizeof(struct pt_softc *));
114 	return pt;
115 }
116 
117 /*
118  * Check if the minor is correct and ensure necessary structures
119  * are properly allocated.
120  */
121 static int
122 check_pty(dev)
123 	dev_t dev;
124 {
125 	struct pt_softc *pti;
126 
127 	if (minor(dev) >= npty) {
128 		struct pt_softc **newpt;
129 		int newnpty;
130 
131 		/* check if the requested pty can be granted */
132 		if (minor(dev) >= maxptys) {
133 	    limit_reached:
134 			tablefull("pty", "increase kern.maxptys");
135 			return (ENXIO);
136 		}
137 
138 		/*
139 		 * Now grab the pty array mutex - we need to ensure
140 		 * that the pty array is consistent while copying it's
141 		 * content to newly allocated, larger space; we also
142 		 * need to be safe against pty_maxptys().
143 		 */
144 		simple_lock(&pt_softc_mutex);
145 
146 		do {
147 			for(newnpty = npty; newnpty <= minor(dev);
148 				newnpty *= 2);
149 
150 			if (newnpty > maxptys)
151 				newnpty = maxptys;
152 
153 			simple_unlock(&pt_softc_mutex);
154 			newpt = ptyarralloc(newnpty);
155 			simple_lock(&pt_softc_mutex);
156 
157 			if (maxptys == npty) {
158 				simple_unlock(&pt_softc_mutex);
159 				goto limit_reached;
160 			}
161 		} while(newnpty > maxptys);
162 
163 		/*
164 		 * If the pty array was not enlarged while we were waiting
165 		 * for mutex, copy current contents of pt_softc[] to newly
166 		 * allocated array and start using the new bigger array.
167 		 */
168 		if (minor(dev) >= npty) {
169 			memcpy(newpt, pt_softc, npty*sizeof(struct pt_softc *));
170 			free(pt_softc, M_DEVBUF);
171 
172 			pt_softc = newpt;
173 			npty = newnpty;
174 		} else {
175 			/* was enlarged when waited fot lock, free new space */
176 			free(newpt, M_DEVBUF);
177 		}
178 
179 		simple_unlock(&pt_softc_mutex);
180 	}
181 
182 	/*
183 	 * If the entry is not yet allocated, allocate one. The mutex is
184 	 * needed so that the state of pt_softc[] array is consistant
185 	 * in case it has been longened above.
186 	 */
187 	if (!pt_softc[minor(dev)]) {
188 		MALLOC(pti, struct pt_softc *, sizeof(struct pt_softc),
189 			M_DEVBUF, M_WAITOK);
190 
191 	 	pti->pt_tty = ttymalloc();
192 
193 		simple_lock(&pt_softc_mutex);
194 
195 		/*
196 		 * Check the entry again - it might have been
197 		 * added while we were waiting for mutex.
198 		 */
199 		if (!pt_softc[minor(dev)]) {
200 			tty_attach(pti->pt_tty);
201 			pt_softc[minor(dev)] = pti;
202 		} else {
203 			ttyfree(pti->pt_tty);
204 			FREE(pti, M_DEVBUF);
205 		}
206 
207 		simple_unlock(&pt_softc_mutex);
208 	}
209 
210 	return (0);
211 }
212 
213 /*
214  * Set maxpty in thread-safe way. Returns 0 in case of error, otherwise
215  * new value of maxptys.
216  */
217 int
218 pty_maxptys(newmax, set)
219 	int newmax, set;
220 {
221 	if (!set)
222 		return (maxptys);
223 
224 	/* the value cannot be set to value lower than current number of ptys */
225 	if (newmax < npty)
226 		return (0);
227 
228 	/* can proceed immediatelly if bigger than current maximum */
229 	if (newmax > maxptys) {
230 		maxptys = newmax;
231 		return (maxptys);
232 	}
233 
234 	/*
235 	 * We have to grab the pt_softc lock, so that we would pick correct
236 	 * value of npty (might be modified in check_pty()).
237 	 */
238 	simple_lock(&pt_softc_mutex);
239 
240 	if (newmax > npty)
241 		maxptys = newmax;
242 
243 	simple_unlock(&pt_softc_mutex);
244 
245 	return (maxptys);
246 }
247 
248 /*
249  * Establish n (or default if n is 1) ptys in the system.
250  */
251 void
252 ptyattach(n)
253 	int n;
254 {
255 	/* maybe should allow 0 => none? */
256 	if (n <= 1)
257 		n = DEFAULT_NPTYS;
258 	pt_softc = ptyarralloc(n);
259 	npty = n;
260 }
261 
262 /*ARGSUSED*/
263 int
264 ptsopen(dev, flag, devtype, p)
265 	dev_t dev;
266 	int flag, devtype;
267 	struct proc *p;
268 {
269 	struct pt_softc *pti;
270 	struct tty *tp;
271 	int error;
272 
273 	if ((error = check_pty(dev)))
274 		return (error);
275 
276 	pti = pt_softc[minor(dev)];
277 	tp = pti->pt_tty;
278 
279 	if (!ISSET(tp->t_state, TS_ISOPEN)) {
280 		ttychars(tp);		/* Set up default chars */
281 		tp->t_iflag = TTYDEF_IFLAG;
282 		tp->t_oflag = TTYDEF_OFLAG;
283 		tp->t_lflag = TTYDEF_LFLAG;
284 		tp->t_cflag = TTYDEF_CFLAG;
285 		tp->t_ispeed = tp->t_ospeed = TTYDEF_SPEED;
286 		ttsetwater(tp);		/* would be done in xxparam() */
287 	} else if (ISSET(tp->t_state, TS_XCLUDE) && p->p_ucred->cr_uid != 0)
288 		return (EBUSY);
289 	if (tp->t_oproc)			/* Ctrlr still around. */
290 		SET(tp->t_state, TS_CARR_ON);
291 	if (!ISSET(flag, O_NONBLOCK))
292 		while (!ISSET(tp->t_state, TS_CARR_ON)) {
293 			tp->t_wopen++;
294 			error = ttysleep(tp, &tp->t_rawq, TTIPRI | PCATCH,
295 			    ttopen, 0);
296 			tp->t_wopen--;
297 			if (error)
298 				return (error);
299 		}
300 	error = (*tp->t_linesw->l_open)(dev, tp);
301 	ptcwakeup(tp, FREAD|FWRITE);
302 	return (error);
303 }
304 
305 int
306 ptsclose(dev, flag, mode, p)
307 	dev_t dev;
308 	int flag, mode;
309 	struct proc *p;
310 {
311 	struct pt_softc *pti = pt_softc[minor(dev)];
312 	struct tty *tp = pti->pt_tty;
313 	int error;
314 
315 	error = (*tp->t_linesw->l_close)(tp, flag);
316 	error |= ttyclose(tp);
317 	ptcwakeup(tp, FREAD|FWRITE);
318 	return (error);
319 }
320 
321 int
322 ptsread(dev, uio, flag)
323 	dev_t dev;
324 	struct uio *uio;
325 	int flag;
326 {
327 	struct proc *p = curproc;
328 	struct pt_softc *pti = pt_softc[minor(dev)];
329 	struct tty *tp = pti->pt_tty;
330 	int error = 0;
331 
332 again:
333 	if (pti->pt_flags & PF_REMOTE) {
334 		while (isbackground(p, tp)) {
335 			if (sigismasked(p, SIGTTIN) ||
336 			    p->p_pgrp->pg_jobc == 0 ||
337 			    p->p_flag & P_PPWAIT)
338 				return (EIO);
339 			pgsignal(p->p_pgrp, SIGTTIN, 1);
340 			error = ttysleep(tp, (caddr_t)&lbolt,
341 					 TTIPRI | PCATCH, ttybg, 0);
342 			if (error)
343 				return (error);
344 		}
345 		if (tp->t_canq.c_cc == 0) {
346 			if (flag & IO_NDELAY)
347 				return (EWOULDBLOCK);
348 			error = ttysleep(tp, (caddr_t)&tp->t_canq,
349 					 TTIPRI | PCATCH, ttyin, 0);
350 			if (error)
351 				return (error);
352 			goto again;
353 		}
354 		while (tp->t_canq.c_cc > 1 && uio->uio_resid > 0)
355 			if (ureadc(getc(&tp->t_canq), uio) < 0) {
356 				error = EFAULT;
357 				break;
358 			}
359 		if (tp->t_canq.c_cc == 1)
360 			(void) getc(&tp->t_canq);
361 		if (tp->t_canq.c_cc)
362 			return (error);
363 	} else
364 		if (tp->t_oproc)
365 			error = (*tp->t_linesw->l_read)(tp, uio, flag);
366 	ptcwakeup(tp, FWRITE);
367 	return (error);
368 }
369 
370 /*
371  * Write to pseudo-tty.
372  * Wakeups of controlling tty will happen
373  * indirectly, when tty driver calls ptsstart.
374  */
375 int
376 ptswrite(dev, uio, flag)
377 	dev_t dev;
378 	struct uio *uio;
379 	int flag;
380 {
381 	struct pt_softc *pti = pt_softc[minor(dev)];
382 	struct tty *tp = pti->pt_tty;
383 
384 	if (tp->t_oproc == 0)
385 		return (EIO);
386 	return ((*tp->t_linesw->l_write)(tp, uio, flag));
387 }
388 
389 /*
390  * Poll pseudo-tty.
391  */
392 int
393 ptspoll(dev, events, p)
394 	dev_t dev;
395 	int events;
396 	struct proc *p;
397 {
398 	struct pt_softc *pti = pt_softc[minor(dev)];
399 	struct tty *tp = pti->pt_tty;
400 
401 	if (tp->t_oproc == 0)
402 		return (EIO);
403 
404 	return ((*tp->t_linesw->l_poll)(tp, events, p));
405 }
406 
407 /*
408  * Start output on pseudo-tty.
409  * Wake up process polling or sleeping for input from controlling tty.
410  */
411 void
412 ptsstart(tp)
413 	struct tty *tp;
414 {
415 	struct pt_softc *pti = pt_softc[minor(tp->t_dev)];
416 
417 	if (ISSET(tp->t_state, TS_TTSTOP))
418 		return;
419 	if (pti->pt_flags & PF_STOPPED) {
420 		pti->pt_flags &= ~PF_STOPPED;
421 		pti->pt_send = TIOCPKT_START;
422 	}
423 	ptcwakeup(tp, FREAD);
424 }
425 
426 void
427 ptsstop(tp, flush)
428 	struct tty *tp;
429 	int flush;
430 {
431 	struct pt_softc *pti = pt_softc[minor(tp->t_dev)];
432 	int flag;
433 
434 	/* note: FLUSHREAD and FLUSHWRITE already ok */
435 	if (flush == 0) {
436 		flush = TIOCPKT_STOP;
437 		pti->pt_flags |= PF_STOPPED;
438 	} else
439 		pti->pt_flags &= ~PF_STOPPED;
440 	pti->pt_send |= flush;
441 	/* change of perspective */
442 	flag = 0;
443 	if (flush & FREAD)
444 		flag |= FWRITE;
445 	if (flush & FWRITE)
446 		flag |= FREAD;
447 	ptcwakeup(tp, flag);
448 }
449 
450 void
451 ptcwakeup(tp, flag)
452 	struct tty *tp;
453 	int flag;
454 {
455 	struct pt_softc *pti = pt_softc[minor(tp->t_dev)];
456 
457 	if (flag & FREAD) {
458 		selwakeup(&pti->pt_selr);
459 		wakeup((caddr_t)&tp->t_outq.c_cf);
460 	}
461 	if (flag & FWRITE) {
462 		selwakeup(&pti->pt_selw);
463 		wakeup((caddr_t)&tp->t_rawq.c_cf);
464 	}
465 }
466 
467 /*ARGSUSED*/
468 int
469 ptcopen(dev, flag, devtype, p)
470 	dev_t dev;
471 	int flag, devtype;
472 	struct proc *p;
473 {
474 	struct pt_softc *pti;
475 	struct tty *tp;
476 	int error;
477 
478 	if ((error = check_pty(dev)))
479 		return (error);
480 
481 	pti = pt_softc[minor(dev)];
482 	tp = pti->pt_tty;
483 
484 	if (tp->t_oproc)
485 		return (EIO);
486 	tp->t_oproc = ptsstart;
487 	(void)(*tp->t_linesw->l_modem)(tp, 1);
488 	CLR(tp->t_lflag, EXTPROC);
489 	pti->pt_flags = 0;
490 	pti->pt_send = 0;
491 	pti->pt_ucntl = 0;
492 	return (0);
493 }
494 
495 /*ARGSUSED*/
496 int
497 ptcclose(dev, flag, devtype, p)
498 	dev_t dev;
499 	int flag, devtype;
500 	struct proc *p;
501 {
502 	struct pt_softc *pti = pt_softc[minor(dev)];
503 	struct tty *tp = pti->pt_tty;
504 
505 	(void)(*tp->t_linesw->l_modem)(tp, 0);
506 	CLR(tp->t_state, TS_CARR_ON);
507 	tp->t_oproc = 0;		/* mark closed */
508 	return (0);
509 }
510 
511 int
512 ptcread(dev, uio, flag)
513 	dev_t dev;
514 	struct uio *uio;
515 	int flag;
516 {
517 	struct pt_softc *pti = pt_softc[minor(dev)];
518 	struct tty *tp = pti->pt_tty;
519 	char buf[BUFSIZ];
520 	int error = 0, cc;
521 
522 	/*
523 	 * We want to block until the slave
524 	 * is open, and there's something to read;
525 	 * but if we lost the slave or we're NBIO,
526 	 * then return the appropriate error instead.
527 	 */
528 	for (;;) {
529 		if (ISSET(tp->t_state, TS_ISOPEN)) {
530 			if (pti->pt_flags&PF_PKT && pti->pt_send) {
531 				error = ureadc((int)pti->pt_send, uio);
532 				if (error)
533 					return (error);
534 				if (pti->pt_send & TIOCPKT_IOCTL) {
535 					cc = min(uio->uio_resid,
536 						sizeof(tp->t_termios));
537 					uiomove((caddr_t) &tp->t_termios,
538 						cc, uio);
539 				}
540 				pti->pt_send = 0;
541 				return (0);
542 			}
543 			if (pti->pt_flags&PF_UCNTL && pti->pt_ucntl) {
544 				error = ureadc((int)pti->pt_ucntl, uio);
545 				if (error)
546 					return (error);
547 				pti->pt_ucntl = 0;
548 				return (0);
549 			}
550 			if (tp->t_outq.c_cc && !ISSET(tp->t_state, TS_TTSTOP))
551 				break;
552 		}
553 		if (!ISSET(tp->t_state, TS_CARR_ON))
554 			return (0);	/* EOF */
555 		if (flag & IO_NDELAY)
556 			return (EWOULDBLOCK);
557 		error = tsleep((caddr_t)&tp->t_outq.c_cf, TTIPRI | PCATCH,
558 			       ttyin, 0);
559 		if (error)
560 			return (error);
561 	}
562 	if (pti->pt_flags & (PF_PKT|PF_UCNTL))
563 		error = ureadc(0, uio);
564 	while (uio->uio_resid > 0 && error == 0) {
565 		cc = q_to_b(&tp->t_outq, buf, min(uio->uio_resid, BUFSIZ));
566 		if (cc <= 0)
567 			break;
568 		error = uiomove(buf, cc, uio);
569 	}
570 	if (tp->t_outq.c_cc <= tp->t_lowat) {
571 		if (ISSET(tp->t_state, TS_ASLEEP)) {
572 			CLR(tp->t_state, TS_ASLEEP);
573 			wakeup((caddr_t)&tp->t_outq);
574 		}
575 		selwakeup(&tp->t_wsel);
576 	}
577 	return (error);
578 }
579 
580 
581 int
582 ptcwrite(dev, uio, flag)
583 	dev_t dev;
584 	struct uio *uio;
585 	int flag;
586 {
587 	struct pt_softc *pti = pt_softc[minor(dev)];
588 	struct tty *tp = pti->pt_tty;
589 	u_char *cp = NULL;
590 	int cc = 0;
591 	u_char locbuf[BUFSIZ];
592 	int cnt = 0;
593 	int error = 0;
594 
595 again:
596 	if (!ISSET(tp->t_state, TS_ISOPEN))
597 		goto block;
598 	if (pti->pt_flags & PF_REMOTE) {
599 		if (tp->t_canq.c_cc)
600 			goto block;
601 		while (uio->uio_resid > 0 && tp->t_canq.c_cc < TTYHOG - 1) {
602 			if (cc == 0) {
603 				cc = min(uio->uio_resid, BUFSIZ);
604 				cc = min(cc, TTYHOG - 1 - tp->t_canq.c_cc);
605 				cp = locbuf;
606 				error = uiomove((caddr_t)cp, cc, uio);
607 				if (error)
608 					return (error);
609 				/* check again for safety */
610 				if (!ISSET(tp->t_state, TS_ISOPEN))
611 					return (EIO);
612 			}
613 			if (cc)
614 				(void) b_to_q((char *)cp, cc, &tp->t_canq);
615 			cc = 0;
616 		}
617 		(void) putc(0, &tp->t_canq);
618 		ttwakeup(tp);
619 		wakeup((caddr_t)&tp->t_canq);
620 		return (0);
621 	}
622 	while (uio->uio_resid > 0) {
623 		if (cc == 0) {
624 			cc = min(uio->uio_resid, BUFSIZ);
625 			cp = locbuf;
626 			error = uiomove((caddr_t)cp, cc, uio);
627 			if (error)
628 				return (error);
629 			/* check again for safety */
630 			if (!ISSET(tp->t_state, TS_ISOPEN))
631 				return (EIO);
632 		}
633 		while (cc > 0) {
634 			if ((tp->t_rawq.c_cc + tp->t_canq.c_cc) >= TTYHOG - 2 &&
635 			   (tp->t_canq.c_cc > 0 || !ISSET(tp->t_iflag, ICANON))) {
636 				wakeup((caddr_t)&tp->t_rawq);
637 				goto block;
638 			}
639 			(*tp->t_linesw->l_rint)(*cp++, tp);
640 			cnt++;
641 			cc--;
642 		}
643 		cc = 0;
644 	}
645 	return (0);
646 block:
647 	/*
648 	 * Come here to wait for slave to open, for space
649 	 * in outq, or space in rawq.
650 	 */
651 	if (!ISSET(tp->t_state, TS_CARR_ON))
652 		return (EIO);
653 	if (flag & IO_NDELAY) {
654 		/* adjust for data copied in but not written */
655 		uio->uio_resid += cc;
656 		if (cnt == 0)
657 			return (EWOULDBLOCK);
658 		return (0);
659 	}
660 	error = tsleep((caddr_t)&tp->t_rawq.c_cf, TTOPRI | PCATCH,
661 		       ttyout, 0);
662 	if (error) {
663 		/* adjust for data copied in but not written */
664 		uio->uio_resid += cc;
665 		return (error);
666 	}
667 	goto again;
668 }
669 
670 int
671 ptcpoll(dev, events, p)
672 	dev_t dev;
673 	int events;
674 	struct proc *p;
675 {
676 	struct pt_softc *pti = pt_softc[minor(dev)];
677 	struct tty *tp = pti->pt_tty;
678 	int revents = 0;
679 	int s = splsoftclock();
680 
681 	if (events & (POLLIN | POLLRDNORM))
682 		if (ISSET(tp->t_state, TS_ISOPEN) &&
683 		    ((tp->t_outq.c_cc > 0 && !ISSET(tp->t_state, TS_TTSTOP)) ||
684 		     ((pti->pt_flags & PF_PKT) && pti->pt_send) ||
685 		     ((pti->pt_flags & PF_UCNTL) && pti->pt_ucntl)))
686 			revents |= events & (POLLIN | POLLRDNORM);
687 
688 	if (events & (POLLOUT | POLLWRNORM))
689 		if (ISSET(tp->t_state, TS_ISOPEN) &&
690 		    ((pti->pt_flags & PF_REMOTE) ?
691 		     (tp->t_canq.c_cc == 0) :
692 		     ((tp->t_rawq.c_cc + tp->t_canq.c_cc < TTYHOG-2) ||
693 		      (tp->t_canq.c_cc == 0 && ISSET(tp->t_iflag, ICANON)))))
694 			revents |= events & (POLLOUT | POLLWRNORM);
695 
696 	if (events & POLLHUP)
697 		if (!ISSET(tp->t_state, TS_CARR_ON))
698 			revents |= POLLHUP;
699 
700 	if (revents == 0) {
701 		if (events & (POLLIN | POLLHUP | POLLRDNORM))
702 			selrecord(p, &pti->pt_selr);
703 
704 		if (events & (POLLOUT | POLLWRNORM))
705 			selrecord(p, &pti->pt_selw);
706 	}
707 
708 	splx(s);
709 	return (revents);
710 }
711 
712 
713 struct tty *
714 ptytty(dev)
715 	dev_t dev;
716 {
717 	struct pt_softc *pti = pt_softc[minor(dev)];
718 	struct tty *tp = pti->pt_tty;
719 
720 	return (tp);
721 }
722 
723 /*ARGSUSED*/
724 int
725 ptyioctl(dev, cmd, data, flag, p)
726 	dev_t dev;
727 	u_long cmd;
728 	caddr_t data;
729 	int flag;
730 	struct proc *p;
731 {
732 	struct pt_softc *pti = pt_softc[minor(dev)];
733 	struct tty *tp = pti->pt_tty;
734 	u_char *cc = tp->t_cc;
735 	int stop, error, sig;
736 
737 	/*
738 	 * IF CONTROLLER STTY THEN MUST FLUSH TO PREVENT A HANG.
739 	 * ttywflush(tp) will hang if there are characters in the outq.
740 	 */
741 	if (cmd == TIOCEXT) {
742 		/*
743 		 * When the EXTPROC bit is being toggled, we need
744 		 * to send an TIOCPKT_IOCTL if the packet driver
745 		 * is turned on.
746 		 */
747 		if (*(int *)data) {
748 			if (pti->pt_flags & PF_PKT) {
749 				pti->pt_send |= TIOCPKT_IOCTL;
750 				ptcwakeup(tp, FREAD);
751 			}
752 			SET(tp->t_lflag, EXTPROC);
753 		} else {
754 			if (ISSET(tp->t_lflag, EXTPROC) &&
755 			    (pti->pt_flags & PF_PKT)) {
756 				pti->pt_send |= TIOCPKT_IOCTL;
757 				ptcwakeup(tp, FREAD);
758 			}
759 			CLR(tp->t_lflag, EXTPROC);
760 		}
761 		return(0);
762 	} else
763 	if (cdevsw[major(dev)].d_open == ptcopen)
764 		switch (cmd) {
765 
766 		case TIOCGPGRP:
767 #ifdef COMPAT_SUNOS
768 			{
769 			/*
770 			 * I'm not sure about SunOS TIOCGPGRP semantics
771 			 * on PTYs, but it's something like this:
772 			 */
773 			extern struct emul emul_sunos;
774 			if (p->p_emul == &emul_sunos && tp->t_pgrp == 0)
775 				return (EIO);
776 			*(int *)data = tp->t_pgrp->pg_id;
777 			return (0);
778 			}
779 #endif
780 			/*
781 			 * We avoid calling ttioctl on the controller since,
782 			 * in that case, tp must be the controlling terminal.
783 			 */
784 			*(int *)data = tp->t_pgrp ? tp->t_pgrp->pg_id : 0;
785 			return (0);
786 
787 		case TIOCPKT:
788 			if (*(int *)data) {
789 				if (pti->pt_flags & PF_UCNTL)
790 					return (EINVAL);
791 				pti->pt_flags |= PF_PKT;
792 			} else
793 				pti->pt_flags &= ~PF_PKT;
794 			return (0);
795 
796 		case TIOCUCNTL:
797 			if (*(int *)data) {
798 				if (pti->pt_flags & PF_PKT)
799 					return (EINVAL);
800 				pti->pt_flags |= PF_UCNTL;
801 			} else
802 				pti->pt_flags &= ~PF_UCNTL;
803 			return (0);
804 
805 		case TIOCREMOTE:
806 			if (*(int *)data)
807 				pti->pt_flags |= PF_REMOTE;
808 			else
809 				pti->pt_flags &= ~PF_REMOTE;
810 			ttyflush(tp, FREAD|FWRITE);
811 			return (0);
812 
813 #ifdef COMPAT_OLDTTY
814 		case TIOCSETP:
815 		case TIOCSETN:
816 #endif
817 		case TIOCSETD:
818 		case TIOCSETA:
819 		case TIOCSETAW:
820 		case TIOCSETAF:
821 			ndflush(&tp->t_outq, tp->t_outq.c_cc);
822 			break;
823 
824 		case TIOCSIG:
825 			sig = (int)(long)*(caddr_t *)data;
826 			if (sig <= 0 || sig >= NSIG)
827 				return (EINVAL);
828 			if (!ISSET(tp->t_lflag, NOFLSH))
829 				ttyflush(tp, FREAD|FWRITE);
830 			pgsignal(tp->t_pgrp, sig, 1);
831 			if ((sig == SIGINFO) &&
832 			    (!ISSET(tp->t_lflag, NOKERNINFO)))
833 				ttyinfo(tp);
834 			return(0);
835 		}
836 	error = (*tp->t_linesw->l_ioctl)(tp, cmd, data, flag, p);
837 	if (error < 0)
838 		 error = ttioctl(tp, cmd, data, flag, p);
839 	if (error < 0) {
840 		if (pti->pt_flags & PF_UCNTL &&
841 		    (cmd & ~0xff) == UIOCCMD(0)) {
842 			if (cmd & 0xff) {
843 				pti->pt_ucntl = (u_char)cmd;
844 				ptcwakeup(tp, FREAD);
845 			}
846 			return (0);
847 		}
848 		error = ENOTTY;
849 	}
850 	/*
851 	 * If external processing and packet mode send ioctl packet.
852 	 */
853 	if (ISSET(tp->t_lflag, EXTPROC) && (pti->pt_flags & PF_PKT)) {
854 		switch(cmd) {
855 		case TIOCSETA:
856 		case TIOCSETAW:
857 		case TIOCSETAF:
858 #ifdef COMPAT_OLDTTY
859 		case TIOCSETP:
860 		case TIOCSETN:
861 		case TIOCSETC:
862 		case TIOCSLTC:
863 		case TIOCLBIS:
864 		case TIOCLBIC:
865 		case TIOCLSET:
866 #endif
867 			pti->pt_send |= TIOCPKT_IOCTL;
868 			ptcwakeup(tp, FREAD);
869 		default:
870 			break;
871 		}
872 	}
873 	stop = ISSET(tp->t_iflag, IXON) && CCEQ(cc[VSTOP], CTRL('s'))
874 		&& CCEQ(cc[VSTART], CTRL('q'));
875 	if (pti->pt_flags & PF_NOSTOP) {
876 		if (stop) {
877 			pti->pt_send &= ~TIOCPKT_NOSTOP;
878 			pti->pt_send |= TIOCPKT_DOSTOP;
879 			pti->pt_flags &= ~PF_NOSTOP;
880 			ptcwakeup(tp, FREAD);
881 		}
882 	} else {
883 		if (!stop) {
884 			pti->pt_send &= ~TIOCPKT_DOSTOP;
885 			pti->pt_send |= TIOCPKT_NOSTOP;
886 			pti->pt_flags |= PF_NOSTOP;
887 			ptcwakeup(tp, FREAD);
888 		}
889 	}
890 	return (error);
891 }
892