xref: /netbsd-src/sys/kern/tty_pty.c (revision 404fbe5fb94ca1e054339640cabb2801ce52dd30)
1 /*	$NetBSD: tty_pty.c,v 1.114 2008/11/15 05:58:33 mrg 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. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  *
31  *	@(#)tty_pty.c	8.4 (Berkeley) 2/20/95
32  */
33 
34 /*
35  * Pseudo-teletype Driver
36  * (Actually two drivers, requiring two entries in 'cdevsw')
37  */
38 
39 #include <sys/cdefs.h>
40 __KERNEL_RCSID(0, "$NetBSD: tty_pty.c,v 1.114 2008/11/15 05:58:33 mrg Exp $");
41 
42 #include "opt_ptm.h"
43 
44 #include <sys/param.h>
45 #include <sys/systm.h>
46 #include <sys/ioctl.h>
47 #include <sys/ioctl_compat.h>
48 #include <sys/proc.h>
49 #include <sys/tty.h>
50 #include <sys/stat.h>
51 #include <sys/file.h>
52 #include <sys/kernel.h>
53 #include <sys/vnode.h>
54 #include <sys/namei.h>
55 #include <sys/signalvar.h>
56 #include <sys/uio.h>
57 #include <sys/filedesc.h>
58 #include <sys/conf.h>
59 #include <sys/poll.h>
60 #include <sys/malloc.h>
61 #include <sys/pty.h>
62 #include <sys/kauth.h>
63 
64 #define	DEFAULT_NPTYS		16	/* default number of initial ptys */
65 #define DEFAULT_MAXPTYS		992	/* default maximum number of ptys */
66 
67 #define BUFSIZ 100		/* Chunk size iomoved to/from user */
68 
69 struct	pt_softc {
70 	struct	tty *pt_tty;
71 	int	pt_flags;
72 	struct	selinfo pt_selr, pt_selw;
73 	u_char	pt_send;
74 	u_char	pt_ucntl;
75 };
76 
77 static struct pt_softc **pt_softc = NULL;	/* pty array */
78 static int maxptys = DEFAULT_MAXPTYS;	/* maximum number of ptys (sysctable) */
79 kmutex_t pt_softc_mutex;
80 int npty = 0;			/* for pstat -t */
81 
82 #define	PF_PKT		0x08		/* packet mode */
83 #define	PF_STOPPED	0x10		/* user told stopped */
84 #define	PF_REMOTE	0x20		/* remote and flow controlled input */
85 #define	PF_NOSTOP	0x40
86 #define PF_UCNTL	0x80		/* user control mode */
87 
88 void	ptyattach(int);
89 void	ptcwakeup(struct tty *, int);
90 void	ptsstart(struct tty *);
91 int	pty_maxptys(int, int);
92 
93 static struct pt_softc **ptyarralloc(int);
94 
95 dev_type_open(ptcopen);
96 dev_type_close(ptcclose);
97 dev_type_read(ptcread);
98 dev_type_write(ptcwrite);
99 dev_type_poll(ptcpoll);
100 dev_type_kqfilter(ptckqfilter);
101 
102 dev_type_open(ptsopen);
103 dev_type_close(ptsclose);
104 dev_type_read(ptsread);
105 dev_type_write(ptswrite);
106 dev_type_stop(ptsstop);
107 dev_type_poll(ptspoll);
108 
109 dev_type_ioctl(ptyioctl);
110 dev_type_tty(ptytty);
111 
112 const struct cdevsw ptc_cdevsw = {
113 	ptcopen, ptcclose, ptcread, ptcwrite, ptyioctl,
114 	nullstop, ptytty, ptcpoll, nommap, ptckqfilter, D_TTY
115 };
116 
117 const struct cdevsw pts_cdevsw = {
118 	ptsopen, ptsclose, ptsread, ptswrite, ptyioctl,
119 	ptsstop, ptytty, ptspoll, nommap, ttykqfilter, D_TTY
120 };
121 
122 #if defined(pmax)
123 const struct cdevsw ptc_ultrix_cdevsw = {
124 	ptcopen, ptcclose, ptcread, ptcwrite, ptyioctl,
125 	nullstop, ptytty, ptcpoll, nommap, ptckqfilter, D_TTY
126 };
127 
128 const struct cdevsw pts_ultrix_cdevsw = {
129 	ptsopen, ptsclose, ptsread, ptswrite, ptyioctl,
130 	ptsstop, ptytty, ptspoll, nommap, ttykqfilter, D_TTY
131 };
132 #endif /* defined(pmax) */
133 
134 /*
135  * Check if a pty is free to use.
136  */
137 int
138 pty_isfree(int minor, int lock)
139 {
140 	struct pt_softc *pt = pt_softc[minor];
141 	if (lock)
142 		mutex_enter(&pt_softc_mutex);
143 	minor = pt == NULL || pt->pt_tty == NULL ||
144 	    pt->pt_tty->t_oproc == NULL;
145 	if (lock)
146 		mutex_exit(&pt_softc_mutex);
147 	return minor;
148 }
149 
150 /*
151  * Allocate and zero array of nelem elements.
152  */
153 static struct pt_softc **
154 ptyarralloc(nelem)
155 	int nelem;
156 {
157 	struct pt_softc **pt;
158 	nelem += 10;
159 	pt = malloc(nelem * sizeof *pt, M_DEVBUF, M_WAITOK | M_ZERO);
160 	return pt;
161 }
162 
163 /*
164  * Check if the minor is correct and ensure necessary structures
165  * are properly allocated.
166  */
167 int
168 pty_check(int ptn)
169 {
170 	struct pt_softc *pti;
171 
172 	if (ptn >= npty) {
173 		struct pt_softc **newpt, **oldpt;
174 		int newnpty;
175 
176 		/* check if the requested pty can be granted */
177 		if (ptn >= maxptys) {
178 	    limit_reached:
179 			tablefull("pty", "increase kern.maxptys");
180 			return (ENXIO);
181 		}
182 
183 		/* Allocate a larger pty array */
184 		for (newnpty = npty; newnpty <= ptn;)
185 			newnpty *= 2;
186 		if (newnpty > maxptys)
187 			newnpty = maxptys;
188 		newpt = ptyarralloc(newnpty);
189 
190 		/*
191 		 * Now grab the pty array mutex - we need to ensure
192 		 * that the pty array is consistent while copying it's
193 		 * content to newly allocated, larger space; we also
194 		 * need to be safe against pty_maxptys().
195 		 */
196 		mutex_enter(&pt_softc_mutex);
197 
198 		if (newnpty >= maxptys) {
199 			/* limit cut away beneath us... */
200 			newnpty = maxptys;
201 			if (ptn >= newnpty) {
202 				mutex_exit(&pt_softc_mutex);
203 				free(newpt, M_DEVBUF);
204 				goto limit_reached;
205 			}
206 		}
207 
208 		/*
209 		 * If the pty array was not enlarged while we were waiting
210 		 * for mutex, copy current contents of pt_softc[] to newly
211 		 * allocated array and start using the new bigger array.
212 		 */
213 		if (newnpty > npty) {
214 			memcpy(newpt, pt_softc, npty*sizeof(struct pt_softc *));
215 			oldpt = pt_softc;
216 			pt_softc = newpt;
217 			npty = newnpty;
218 		} else {
219 			/* was enlarged when waited for lock, free new space */
220 			oldpt = newpt;
221 		}
222 
223 		mutex_exit(&pt_softc_mutex);
224 		free(oldpt, M_DEVBUF);
225 	}
226 
227 	/*
228 	 * If the entry is not yet allocated, allocate one. The mutex is
229 	 * needed so that the state of pt_softc[] array is consistant
230 	 * in case it has been lengthened above.
231 	 */
232 	if (!pt_softc[ptn]) {
233 		pti = malloc(sizeof(struct pt_softc),
234 		    M_DEVBUF, M_WAITOK | M_ZERO);
235 
236 		selinit(&pti->pt_selr);
237 		selinit(&pti->pt_selw);
238 		pti->pt_tty = ttymalloc();
239 
240 		mutex_enter(&pt_softc_mutex);
241 
242 		/*
243 		 * Check the entry again - it might have been
244 		 * added while we were waiting for mutex.
245 		 */
246 		if (pt_softc[ptn]) {
247 			mutex_exit(&pt_softc_mutex);
248 			ttyfree(pti->pt_tty);
249 			seldestroy(&pti->pt_selr);
250 			seldestroy(&pti->pt_selw);
251 			free(pti, M_DEVBUF);
252 			return (0);
253 		}
254 		tty_attach(pti->pt_tty);
255 		pt_softc[ptn] = pti;
256 
257 		mutex_exit(&pt_softc_mutex);
258 	}
259 
260 	return (0);
261 }
262 
263 /*
264  * Set maxpty in thread-safe way. Returns 0 in case of error, otherwise
265  * new value of maxptys.
266  */
267 int
268 pty_maxptys(newmax, set)
269 	int newmax, set;
270 {
271 	if (!set)
272 		return (maxptys);
273 
274 	/*
275 	 * We have to grab the pt_softc lock, so that we would pick correct
276 	 * value of npty (might be modified in pty_check()).
277 	 */
278 	mutex_enter(&pt_softc_mutex);
279 
280 	/*
281 	 * The value cannot be set to value lower than the highest pty
282 	 * number ever allocated.
283 	 */
284 	if (newmax >= npty)
285 		maxptys = newmax;
286 	else
287 		newmax = 0;
288 
289 	mutex_exit(&pt_softc_mutex);
290 
291 	return newmax;
292 }
293 
294 /*
295  * Establish n (or default if n is 1) ptys in the system.
296  */
297 void
298 ptyattach(n)
299 	int n;
300 {
301 
302 	mutex_init(&pt_softc_mutex, MUTEX_DEFAULT, IPL_NONE);
303 
304 	/* maybe should allow 0 => none? */
305 	if (n <= 1)
306 		n = DEFAULT_NPTYS;
307 	pt_softc = ptyarralloc(n);
308 	npty = n;
309 #ifndef NO_DEV_PTM
310 	ptmattach(1);
311 #endif
312 }
313 
314 /*ARGSUSED*/
315 int
316 ptsopen(dev_t dev, int flag, int devtype, struct lwp *l)
317 {
318 	struct pt_softc *pti;
319 	struct tty *tp;
320 	int error;
321 	int ptn = minor(dev);
322 
323 	if ((error = pty_check(ptn)) != 0)
324 		return (error);
325 
326 	mutex_spin_enter(&tty_lock);
327 	pti = pt_softc[ptn];
328 	tp = pti->pt_tty;
329 	if (!ISSET(tp->t_state, TS_ISOPEN)) {
330 		ttychars(tp);		/* Set up default chars */
331 		tp->t_iflag = TTYDEF_IFLAG;
332 		tp->t_oflag = TTYDEF_OFLAG;
333 		tp->t_lflag = TTYDEF_LFLAG;
334 		tp->t_cflag = TTYDEF_CFLAG;
335 		tp->t_ispeed = tp->t_ospeed = TTYDEF_SPEED;
336 		ttsetwater(tp);		/* would be done in xxparam() */
337 	} else if (kauth_authorize_device_tty(l->l_cred, KAUTH_DEVICE_TTY_OPEN,
338 	    tp) != 0) {
339 		mutex_spin_exit(&tty_lock);
340 		return (EBUSY);
341 	}
342 	if (tp->t_oproc)			/* Ctrlr still around. */
343 		SET(tp->t_state, TS_CARR_ON);
344 	if (!ISSET(flag, O_NONBLOCK)) {
345 		while (!ISSET(tp->t_state, TS_CARR_ON)) {
346 			tp->t_wopen++;
347 			error = ttysleep(tp, &tp->t_rawcv, true, 0);
348 			tp->t_wopen--;
349 			if (error) {
350 				mutex_spin_exit(&tty_lock);
351 				return (error);
352 			}
353 		}
354 	}
355 	mutex_spin_exit(&tty_lock);
356 	error = (*tp->t_linesw->l_open)(dev, tp);
357 	ptcwakeup(tp, FREAD|FWRITE);
358 	return (error);
359 }
360 
361 int
362 ptsclose(dev_t dev, int flag, int mode, struct lwp *l)
363 {
364 	struct pt_softc *pti = pt_softc[minor(dev)];
365 	struct tty *tp = pti->pt_tty;
366 	int error;
367 
368 	error = (*tp->t_linesw->l_close)(tp, flag);
369 	error |= ttyclose(tp);
370 	ptcwakeup(tp, FREAD|FWRITE);
371 	return (error);
372 }
373 
374 int
375 ptsread(dev, uio, flag)
376 	dev_t dev;
377 	struct uio *uio;
378 	int flag;
379 {
380 	struct proc *p = curproc;
381 	struct pt_softc *pti = pt_softc[minor(dev)];
382 	struct tty *tp = pti->pt_tty;
383 	int error = 0;
384 	int cc, c;
385 
386 again:
387 	if (pti->pt_flags & PF_REMOTE) {
388 		mutex_spin_enter(&tty_lock);
389 		while (isbackground(p, tp)) {	/* XXXSMP */
390 			if (sigismasked(curlwp, SIGTTIN) ||
391 			    p->p_pgrp->pg_jobc == 0 ||
392 			    p->p_lflag & PL_PPWAIT) {
393 				mutex_spin_exit(&tty_lock);
394 				return (EIO);
395 			}
396 			ttysig(tp, TTYSIG_PG1, SIGTTIN);
397 			error = ttysleep(tp, &lbolt, true, 0);
398 			if (error) {
399 				mutex_spin_exit(&tty_lock);
400 				return (error);
401 			}
402 		}
403 		if (tp->t_canq.c_cc == 0) {
404 			if (flag & IO_NDELAY) {
405 				mutex_spin_exit(&tty_lock);
406 				return (EWOULDBLOCK);
407 			}
408 			error = ttysleep(tp, &tp->t_cancv, true, 0);
409 			mutex_spin_exit(&tty_lock);
410 			if (error)
411 				return (error);
412 			goto again;
413 		}
414 		while(error == 0 && tp->t_canq.c_cc > 1 && uio->uio_resid > 0) {
415 			c = getc(&tp->t_canq);
416 			mutex_spin_exit(&tty_lock);
417 			error = ureadc(c, uio);
418 			mutex_spin_enter(&tty_lock);
419 			/* Re-check terminal state here? */
420 		}
421 		if (tp->t_canq.c_cc == 1)
422 			(void) getc(&tp->t_canq);
423 		cc = tp->t_canq.c_cc;
424 		mutex_spin_exit(&tty_lock);
425 		if (cc)
426 			return (error);
427 	} else if (tp->t_oproc)
428 		error = (*tp->t_linesw->l_read)(tp, uio, flag);
429 	ptcwakeup(tp, FWRITE);
430 	return (error);
431 }
432 
433 /*
434  * Write to pseudo-tty.
435  * Wakeups of controlling tty will happen
436  * indirectly, when tty driver calls ptsstart.
437  */
438 int
439 ptswrite(dev, uio, flag)
440 	dev_t dev;
441 	struct uio *uio;
442 	int flag;
443 {
444 	struct pt_softc *pti = pt_softc[minor(dev)];
445 	struct tty *tp = pti->pt_tty;
446 
447 	if (tp->t_oproc == 0)
448 		return (EIO);
449 	return ((*tp->t_linesw->l_write)(tp, uio, flag));
450 }
451 
452 /*
453  * Poll pseudo-tty.
454  */
455 int
456 ptspoll(dev, events, l)
457 	dev_t dev;
458 	int events;
459 	struct lwp *l;
460 {
461 	struct pt_softc *pti = pt_softc[minor(dev)];
462 	struct tty *tp = pti->pt_tty;
463 
464 	if (tp->t_oproc == 0)
465 		return (POLLHUP);
466 
467 	return ((*tp->t_linesw->l_poll)(tp, events, l));
468 }
469 
470 /*
471  * Start output on pseudo-tty.
472  * Wake up process polling or sleeping for input from controlling tty.
473  */
474 void
475 ptsstart(tp)
476 	struct tty *tp;
477 {
478 	struct pt_softc *pti = pt_softc[minor(tp->t_dev)];
479 
480 	KASSERT(mutex_owned(&tty_lock));
481 
482 	if (ISSET(tp->t_state, TS_TTSTOP))
483 		return;
484 	if (pti->pt_flags & PF_STOPPED) {
485 		pti->pt_flags &= ~PF_STOPPED;
486 		pti->pt_send = TIOCPKT_START;
487 	}
488 
489 	selnotify(&pti->pt_selr, 0, NOTE_SUBMIT);
490 	cv_broadcast(&tp->t_outcvf);
491 }
492 
493 /*
494  * Stop output.
495  */
496 void
497 ptsstop(tp, flush)
498 	struct tty *tp;
499 	int flush;
500 {
501 	struct pt_softc *pti = pt_softc[minor(tp->t_dev)];
502 
503 	KASSERT(mutex_owned(&tty_lock));
504 
505 	/* note: FLUSHREAD and FLUSHWRITE already ok */
506 	if (flush == 0) {
507 		flush = TIOCPKT_STOP;
508 		pti->pt_flags |= PF_STOPPED;
509 	} else
510 		pti->pt_flags &= ~PF_STOPPED;
511 	pti->pt_send |= flush;
512 
513 	/* change of perspective */
514 	if (flush & FREAD) {
515 		selnotify(&pti->pt_selw, 0, NOTE_SUBMIT);
516 		cv_broadcast(&tp->t_rawcvf);
517 	}
518 	if (flush & FWRITE) {
519 		selnotify(&pti->pt_selr, 0, NOTE_SUBMIT);
520 		cv_broadcast(&tp->t_outcvf);
521 	}
522 }
523 
524 void
525 ptcwakeup(tp, flag)
526 	struct tty *tp;
527 	int flag;
528 {
529 	struct pt_softc *pti = pt_softc[minor(tp->t_dev)];
530 
531 	mutex_spin_enter(&tty_lock);
532 	if (flag & FREAD) {
533 		selnotify(&pti->pt_selr, 0, NOTE_SUBMIT);
534 		cv_broadcast(&tp->t_outcvf);
535 	}
536 	if (flag & FWRITE) {
537 		selnotify(&pti->pt_selw, 0, NOTE_SUBMIT);
538 		cv_broadcast(&tp->t_rawcvf);
539 	}
540 	mutex_spin_exit(&tty_lock);
541 }
542 
543 /*ARGSUSED*/
544 int
545 ptcopen(dev_t dev, int flag, int devtype, struct lwp *l)
546 {
547 	struct pt_softc *pti;
548 	struct tty *tp;
549 	int error;
550 	int ptn = minor(dev);
551 
552 	if ((error = pty_check(ptn)) != 0)
553 		return (error);
554 
555 	pti = pt_softc[ptn];
556 	tp = pti->pt_tty;
557 
558 	mutex_spin_enter(&tty_lock);
559 	if (tp->t_oproc) {
560 		mutex_spin_exit(&tty_lock);
561 		return (EIO);
562 	}
563 	tp->t_oproc = ptsstart;
564 	mutex_spin_exit(&tty_lock);
565 	(void)(*tp->t_linesw->l_modem)(tp, 1);
566 	CLR(tp->t_lflag, EXTPROC);
567 	pti->pt_flags = 0;
568 	pti->pt_send = 0;
569 	pti->pt_ucntl = 0;
570 	return (0);
571 }
572 
573 /*ARGSUSED*/
574 int
575 ptcclose(dev_t dev, int flag, int devtype, struct lwp *l)
576 {
577 	struct pt_softc *pti = pt_softc[minor(dev)];
578 	struct tty *tp = pti->pt_tty;
579 
580 	(void)(*tp->t_linesw->l_modem)(tp, 0);
581 	mutex_spin_enter(&tty_lock);
582 	CLR(tp->t_state, TS_CARR_ON);
583 	tp->t_oproc = 0;		/* mark closed */
584 	mutex_spin_exit(&tty_lock);
585 	return (0);
586 }
587 
588 int
589 ptcread(dev, uio, flag)
590 	dev_t dev;
591 	struct uio *uio;
592 	int flag;
593 {
594 	struct pt_softc *pti = pt_softc[minor(dev)];
595 	struct tty *tp = pti->pt_tty;
596 	u_char bf[BUFSIZ];
597 	int error = 0, cc;
598 
599 	/*
600 	 * We want to block until the slave
601 	 * is open, and there's something to read;
602 	 * but if we lost the slave or we're NBIO,
603 	 * then return the appropriate error instead.
604 	 */
605 	mutex_spin_enter(&tty_lock);
606 	for (;;) {
607 		if (ISSET(tp->t_state, TS_ISOPEN)) {
608 			if (pti->pt_flags & PF_PKT && pti->pt_send) {
609 				mutex_spin_exit(&tty_lock);
610 				error = ureadc((int)pti->pt_send, uio);
611 				if (error)
612 					return (error);
613 				/*
614 				 * Since we don't have the tty locked, there's
615 				 * a risk of messing up `t_termios'. This is
616 				 * relevant only if the tty got closed and then
617 				 * opened again while we were out uiomoving.
618 				 */
619 				if (pti->pt_send & TIOCPKT_IOCTL) {
620 					cc = min(uio->uio_resid,
621 						sizeof(tp->t_termios));
622 					uiomove((void *) &tp->t_termios,
623 						cc, uio);
624 				}
625 				pti->pt_send = 0;
626 				return (0);
627 			}
628 			if (pti->pt_flags & PF_UCNTL && pti->pt_ucntl) {
629 				mutex_spin_exit(&tty_lock);
630 				error = ureadc((int)pti->pt_ucntl, uio);
631 				if (error)
632 					return (error);
633 				pti->pt_ucntl = 0;
634 				return (0);
635 			}
636 			if (tp->t_outq.c_cc && !ISSET(tp->t_state, TS_TTSTOP))
637 				break;
638 		}
639 		if (!ISSET(tp->t_state, TS_CARR_ON)) {
640 			error = 0;	/* EOF */
641 			goto out;
642 		}
643 		if (flag & IO_NDELAY) {
644 			error = EWOULDBLOCK;
645 			goto out;
646 		}
647 		error = cv_wait_sig(&tp->t_outcvf, &tty_lock);
648 		if (error)
649 			goto out;
650 	}
651 
652 	if (pti->pt_flags & (PF_PKT|PF_UCNTL)) {
653 		mutex_spin_exit(&tty_lock);
654 		error = ureadc(0, uio);
655 		mutex_spin_enter(&tty_lock);
656 		if (error == 0 && !ISSET(tp->t_state, TS_ISOPEN))
657 			error = EIO;
658 	}
659 	while (uio->uio_resid > 0 && error == 0) {
660 		cc = q_to_b(&tp->t_outq, bf, min(uio->uio_resid, BUFSIZ));
661 		if (cc <= 0)
662 			break;
663 		mutex_spin_exit(&tty_lock);
664 		error = uiomove(bf, cc, uio);
665 		mutex_spin_enter(&tty_lock);
666 		if (error == 0 && !ISSET(tp->t_state, TS_ISOPEN))
667 			error = EIO;
668 	}
669 	ttypull(tp);
670 out:
671 	mutex_spin_exit(&tty_lock);
672 	return (error);
673 }
674 
675 
676 int
677 ptcwrite(dev, uio, flag)
678 	dev_t dev;
679 	struct uio *uio;
680 	int flag;
681 {
682 	struct pt_softc *pti = pt_softc[minor(dev)];
683 	struct tty *tp = pti->pt_tty;
684 	u_char *cp = NULL;
685 	int cc = 0;
686 	u_char locbuf[BUFSIZ];
687 	int cnt = 0;
688 	int error = 0;
689 
690 again:
691 	mutex_spin_enter(&tty_lock);
692 	if (!ISSET(tp->t_state, TS_ISOPEN))
693 		goto block;
694 	if (pti->pt_flags & PF_REMOTE) {
695 		if (tp->t_canq.c_cc)
696 			goto block;
697 		while (uio->uio_resid > 0 && tp->t_canq.c_cc < TTYHOG - 1) {
698 			if (cc == 0) {
699 				cc = min(uio->uio_resid, BUFSIZ);
700 				cc = min(cc, TTYHOG - 1 - tp->t_canq.c_cc);
701 				cp = locbuf;
702 				mutex_spin_exit(&tty_lock);
703 				error = uiomove((void *)cp, cc, uio);
704 				if (error)
705 					return (error);
706 				mutex_spin_enter(&tty_lock);
707 				/* check again for safety */
708 				if (!ISSET(tp->t_state, TS_ISOPEN)) {
709 					/*
710 					 * adjust for data copied in but not
711 					 * written
712 					 */
713 					uio->uio_resid += cc;
714 					error = EIO;
715 					goto out;
716 				}
717 			}
718 			if (cc)
719 				(void) b_to_q(cp, cc, &tp->t_canq);
720 			cc = 0;
721 		}
722 		(void) putc(0, &tp->t_canq);
723 		ttwakeup(tp);
724 		cv_broadcast(&tp->t_cancv);
725 		error = 0;
726 		goto out;
727 	}
728 	while (uio->uio_resid > 0) {
729 		if (cc == 0) {
730 			cc = min(uio->uio_resid, BUFSIZ);
731 			cp = locbuf;
732 			mutex_spin_exit(&tty_lock);
733 			error = uiomove((void *)cp, cc, uio);
734 			if (error)
735 				return (error);
736 			mutex_spin_enter(&tty_lock);
737 			/* check again for safety */
738 			if (!ISSET(tp->t_state, TS_ISOPEN)) {
739 				/* adjust for data copied in but not written */
740 				uio->uio_resid += cc;
741 				error = EIO;
742 				goto out;
743 			}
744 		}
745 		while (cc > 0) {
746 			if ((tp->t_rawq.c_cc + tp->t_canq.c_cc) >= TTYHOG - 2 &&
747 			   (tp->t_canq.c_cc > 0 || !ISSET(tp->t_lflag, ICANON))) {
748 				cv_broadcast(&tp->t_rawcv);
749 				goto block;
750 			}
751 			/* XXX - should change l_rint to be called with lock
752 			 *	 see also tty.c:ttyinput_wlock()
753 			 */
754 			mutex_spin_exit(&tty_lock);
755 			(*tp->t_linesw->l_rint)(*cp++, tp);
756 			mutex_spin_enter(&tty_lock);
757 			cnt++;
758 			cc--;
759 		}
760 		cc = 0;
761 	}
762 	error = 0;
763 	goto out;
764 
765 block:
766 	/*
767 	 * Come here to wait for slave to open, for space
768 	 * in outq, or space in rawq.
769 	 */
770 	if (!ISSET(tp->t_state, TS_CARR_ON)) {
771 		/* adjust for data copied in but not written */
772 		uio->uio_resid += cc;
773 		error = EIO;
774 		goto out;
775 	}
776 	if (flag & IO_NDELAY) {
777 		/* adjust for data copied in but not written */
778 		uio->uio_resid += cc;
779 		error = cnt == 0 ? EWOULDBLOCK : 0;
780 		goto out;
781 	}
782 	error = cv_wait_sig(&tp->t_rawcv, &tty_lock);
783 	mutex_spin_exit(&tty_lock);
784 	if (error) {
785 		/* adjust for data copied in but not written */
786 		uio->uio_resid += cc;
787 		return (error);
788 	}
789 	goto again;
790 
791 out:
792 	mutex_spin_exit(&tty_lock);
793 	return (error);
794 }
795 
796 int
797 ptcpoll(dev, events, l)
798 	dev_t dev;
799 	int events;
800 	struct lwp *l;
801 {
802 	struct pt_softc *pti = pt_softc[minor(dev)];
803 	struct tty *tp = pti->pt_tty;
804 	int revents = 0;
805 
806 	mutex_spin_enter(&tty_lock);
807 
808 	if (events & (POLLIN | POLLRDNORM))
809 		if (ISSET(tp->t_state, TS_ISOPEN) &&
810 		    ((tp->t_outq.c_cc > 0 && !ISSET(tp->t_state, TS_TTSTOP)) ||
811 		     ((pti->pt_flags & PF_PKT) && pti->pt_send) ||
812 		     ((pti->pt_flags & PF_UCNTL) && pti->pt_ucntl)))
813 			revents |= events & (POLLIN | POLLRDNORM);
814 
815 	if (events & (POLLOUT | POLLWRNORM))
816 		if (ISSET(tp->t_state, TS_ISOPEN) &&
817 		    ((pti->pt_flags & PF_REMOTE) ?
818 		     (tp->t_canq.c_cc == 0) :
819 		     ((tp->t_rawq.c_cc + tp->t_canq.c_cc < TTYHOG-2) ||
820 		      (tp->t_canq.c_cc == 0 && ISSET(tp->t_lflag, ICANON)))))
821 			revents |= events & (POLLOUT | POLLWRNORM);
822 
823 	if (events & POLLHUP)
824 		if (!ISSET(tp->t_state, TS_CARR_ON))
825 			revents |= POLLHUP;
826 
827 	if (revents == 0) {
828 		if (events & (POLLIN | POLLHUP | POLLRDNORM))
829 			selrecord(l, &pti->pt_selr);
830 
831 		if (events & (POLLOUT | POLLWRNORM))
832 			selrecord(l, &pti->pt_selw);
833 	}
834 
835 	mutex_spin_exit(&tty_lock);
836 
837 	return (revents);
838 }
839 
840 static void
841 filt_ptcrdetach(struct knote *kn)
842 {
843 	struct pt_softc *pti;
844 	struct tty	*tp;
845 
846 	pti = kn->kn_hook;
847 	tp = pti->pt_tty;
848 
849 	mutex_spin_enter(&tty_lock);
850 	SLIST_REMOVE(&pti->pt_selr.sel_klist, kn, knote, kn_selnext);
851 	mutex_spin_exit(&tty_lock);
852 }
853 
854 static int
855 filt_ptcread(struct knote *kn, long hint)
856 {
857 	struct pt_softc *pti;
858 	struct tty	*tp;
859 	int canread;
860 
861 	pti = kn->kn_hook;
862 	tp = pti->pt_tty;
863 
864 	if ((hint & NOTE_SUBMIT) == 0) {
865 		mutex_spin_enter(&tty_lock);
866 	}
867 
868 	canread = (ISSET(tp->t_state, TS_ISOPEN) &&
869 		    ((tp->t_outq.c_cc > 0 && !ISSET(tp->t_state, TS_TTSTOP)) ||
870 		     ((pti->pt_flags & PF_PKT) && pti->pt_send) ||
871 		     ((pti->pt_flags & PF_UCNTL) && pti->pt_ucntl)));
872 
873 	if (canread) {
874 		/*
875 		 * c_cc is number of characters after output post-processing;
876 		 * the amount of data actually read(2) depends on
877 		 * setting of input flags for the terminal.
878 		 */
879 		kn->kn_data = tp->t_outq.c_cc;
880 		if (((pti->pt_flags & PF_PKT) && pti->pt_send) ||
881 		    ((pti->pt_flags & PF_UCNTL) && pti->pt_ucntl))
882 			kn->kn_data++;
883 	}
884 
885 	if ((hint & NOTE_SUBMIT) == 0) {
886 		mutex_spin_exit(&tty_lock);
887 	}
888 
889 	return (canread);
890 }
891 
892 static void
893 filt_ptcwdetach(struct knote *kn)
894 {
895 	struct pt_softc *pti;
896 	struct tty	*tp;
897 
898 	pti = kn->kn_hook;
899 	tp = pti->pt_tty;
900 
901 	mutex_spin_enter(&tty_lock);
902 	SLIST_REMOVE(&pti->pt_selw.sel_klist, kn, knote, kn_selnext);
903 	mutex_spin_exit(&tty_lock);
904 }
905 
906 static int
907 filt_ptcwrite(struct knote *kn, long hint)
908 {
909 	struct pt_softc *pti;
910 	struct tty	*tp;
911 	int canwrite;
912 	int nwrite;
913 
914 	pti = kn->kn_hook;
915 	tp = pti->pt_tty;
916 
917 	if ((hint & NOTE_SUBMIT) == 0) {
918 		mutex_spin_enter(&tty_lock);
919 	}
920 
921 	canwrite = (ISSET(tp->t_state, TS_ISOPEN) &&
922 		    ((pti->pt_flags & PF_REMOTE) ?
923 		     (tp->t_canq.c_cc == 0) :
924 		     ((tp->t_rawq.c_cc + tp->t_canq.c_cc < TTYHOG-2) ||
925 		      (tp->t_canq.c_cc == 0 && ISSET(tp->t_lflag, ICANON)))));
926 
927 	if (canwrite) {
928 		if (pti->pt_flags & PF_REMOTE)
929 			nwrite = tp->t_canq.c_cn;
930 		else {
931 			/* this is guaranteed to be > 0 due to above check */
932 			nwrite = tp->t_canq.c_cn
933 				- (tp->t_rawq.c_cc + tp->t_canq.c_cc);
934 		}
935 		kn->kn_data = nwrite;
936 	}
937 
938 	if ((hint & NOTE_SUBMIT) == 0) {
939 		mutex_spin_exit(&tty_lock);
940 	}
941 
942 	return (canwrite);
943 }
944 
945 static const struct filterops ptcread_filtops =
946 	{ 1, NULL, filt_ptcrdetach, filt_ptcread };
947 static const struct filterops ptcwrite_filtops =
948 	{ 1, NULL, filt_ptcwdetach, filt_ptcwrite };
949 
950 int
951 ptckqfilter(dev_t dev, struct knote *kn)
952 {
953 	struct pt_softc *pti = pt_softc[minor(dev)];
954 	struct klist	*klist;
955 
956 	switch (kn->kn_filter) {
957 	case EVFILT_READ:
958 		klist = &pti->pt_selr.sel_klist;
959 		kn->kn_fop = &ptcread_filtops;
960 		break;
961 	case EVFILT_WRITE:
962 		klist = &pti->pt_selw.sel_klist;
963 		kn->kn_fop = &ptcwrite_filtops;
964 		break;
965 	default:
966 		return (EINVAL);
967 	}
968 
969 	kn->kn_hook = pti;
970 
971 	mutex_spin_enter(&tty_lock);
972 	SLIST_INSERT_HEAD(klist, kn, kn_selnext);
973 	mutex_spin_exit(&tty_lock);
974 
975 	return (0);
976 }
977 
978 struct tty *
979 ptytty(dev)
980 	dev_t dev;
981 {
982 	struct pt_softc *pti = pt_softc[minor(dev)];
983 	struct tty *tp = pti->pt_tty;
984 
985 	return (tp);
986 }
987 
988 /*ARGSUSED*/
989 int
990 ptyioctl(dev, cmd, data, flag, l)
991 	dev_t dev;
992 	u_long cmd;
993 	void *data;
994 	int flag;
995 	struct lwp *l;
996 {
997 	struct pt_softc *pti = pt_softc[minor(dev)];
998 	struct tty *tp = pti->pt_tty;
999 	const struct cdevsw *cdev;
1000 	u_char *cc = tp->t_cc;
1001 	int stop, error, sig;
1002 
1003 	/*
1004 	 * IF CONTROLLER STTY THEN MUST FLUSH TO PREVENT A HANG.
1005 	 * ttywflush(tp) will hang if there are characters in the outq.
1006 	 */
1007 	if (cmd == TIOCEXT) {
1008 		/*
1009 		 * When the EXTPROC bit is being toggled, we need
1010 		 * to send an TIOCPKT_IOCTL if the packet driver
1011 		 * is turned on.
1012 		 */
1013 		if (*(int *)data) {
1014 			if (pti->pt_flags & PF_PKT) {
1015 				pti->pt_send |= TIOCPKT_IOCTL;
1016 				ptcwakeup(tp, FREAD);
1017 			}
1018 			SET(tp->t_lflag, EXTPROC);
1019 		} else {
1020 			if (ISSET(tp->t_lflag, EXTPROC) &&
1021 			    (pti->pt_flags & PF_PKT)) {
1022 				pti->pt_send |= TIOCPKT_IOCTL;
1023 				ptcwakeup(tp, FREAD);
1024 			}
1025 			CLR(tp->t_lflag, EXTPROC);
1026 		}
1027 		return(0);
1028 	}
1029 
1030 #ifndef NO_DEV_PTM
1031 	/* Allow getting the name from either the master or the slave */
1032 	if (cmd == TIOCPTSNAME)
1033 		return pty_fill_ptmget(l, dev, -1, -1, data);
1034 #endif
1035 
1036 	cdev = cdevsw_lookup(dev);
1037 	if (cdev != NULL && cdev->d_open == ptcopen)
1038 		switch (cmd) {
1039 #ifndef NO_DEV_PTM
1040 		case TIOCGRANTPT:
1041 			return pty_grant_slave(l, dev);
1042 #endif
1043 
1044 		case TIOCGPGRP:
1045 			/*
1046 			 * We avoid calling ttioctl on the controller since,
1047 			 * in that case, tp must be the controlling terminal.
1048 			 */
1049 			*(int *)data = tp->t_pgrp ? tp->t_pgrp->pg_id : 0;
1050 			return (0);
1051 
1052 		case TIOCPKT:
1053 			if (*(int *)data) {
1054 				if (pti->pt_flags & PF_UCNTL)
1055 					return (EINVAL);
1056 				pti->pt_flags |= PF_PKT;
1057 			} else
1058 				pti->pt_flags &= ~PF_PKT;
1059 			return (0);
1060 
1061 		case TIOCUCNTL:
1062 			if (*(int *)data) {
1063 				if (pti->pt_flags & PF_PKT)
1064 					return (EINVAL);
1065 				pti->pt_flags |= PF_UCNTL;
1066 			} else
1067 				pti->pt_flags &= ~PF_UCNTL;
1068 			return (0);
1069 
1070 		case TIOCREMOTE:
1071 			if (*(int *)data)
1072 				pti->pt_flags |= PF_REMOTE;
1073 			else
1074 				pti->pt_flags &= ~PF_REMOTE;
1075 			mutex_spin_enter(&tty_lock);
1076 			ttyflush(tp, FREAD|FWRITE);
1077 			mutex_spin_exit(&tty_lock);
1078 			return (0);
1079 
1080 		case TIOCSETP:
1081 		case TIOCSETN:
1082 		case TIOCSETD:
1083 		case TIOCSETA:
1084 		case TIOCSETAW:
1085 		case TIOCSETAF:
1086 			mutex_spin_enter(&tty_lock);
1087 			ndflush(&tp->t_outq, tp->t_outq.c_cc);
1088 			mutex_spin_exit(&tty_lock);
1089 			break;
1090 
1091 		case TIOCSIG:
1092 			sig = (int)(long)*(void **)data;
1093 			if (sig <= 0 || sig >= NSIG)
1094 				return (EINVAL);
1095 			mutex_spin_enter(&tty_lock);
1096 			if (!ISSET(tp->t_lflag, NOFLSH))
1097 				ttyflush(tp, FREAD|FWRITE);
1098 			tp->t_state |= TS_SIGINFO;
1099 			ttysig(tp, TTYSIG_PG1, sig);
1100 			mutex_spin_exit(&tty_lock);
1101 			return (0);
1102 
1103 		case FIONREAD:
1104 			mutex_spin_enter(&tty_lock);
1105 			*(int *)data = tp->t_outq.c_cc;
1106 			mutex_spin_exit(&tty_lock);
1107 			return (0);
1108 		}
1109 
1110 	error = (*tp->t_linesw->l_ioctl)(tp, cmd, data, flag, l);
1111 	if (error == EPASSTHROUGH)
1112 		 error = ttioctl(tp, cmd, data, flag, l);
1113 	if (error == EPASSTHROUGH) {
1114 		if (pti->pt_flags & PF_UCNTL &&
1115 		    (cmd & ~0xff) == UIOCCMD(0)) {
1116 			if (cmd & 0xff) {
1117 				pti->pt_ucntl = (u_char)cmd;
1118 				ptcwakeup(tp, FREAD);
1119 			}
1120 			return (0);
1121 		}
1122 	}
1123 	/*
1124 	 * If external processing and packet mode send ioctl packet.
1125 	 */
1126 	if (ISSET(tp->t_lflag, EXTPROC) && (pti->pt_flags & PF_PKT)) {
1127 		switch(cmd) {
1128 		case TIOCSETA:
1129 		case TIOCSETAW:
1130 		case TIOCSETAF:
1131 		case TIOCSETP:
1132 		case TIOCSETN:
1133 		case TIOCSETC:
1134 		case TIOCSLTC:
1135 		case TIOCLBIS:
1136 		case TIOCLBIC:
1137 		case TIOCLSET:
1138 			pti->pt_send |= TIOCPKT_IOCTL;
1139 			ptcwakeup(tp, FREAD);
1140 		default:
1141 			break;
1142 		}
1143 	}
1144 	stop = ISSET(tp->t_iflag, IXON) && CCEQ(cc[VSTOP], CTRL('s'))
1145 		&& CCEQ(cc[VSTART], CTRL('q'));
1146 	if (pti->pt_flags & PF_NOSTOP) {
1147 		if (stop) {
1148 			pti->pt_send &= ~TIOCPKT_NOSTOP;
1149 			pti->pt_send |= TIOCPKT_DOSTOP;
1150 			pti->pt_flags &= ~PF_NOSTOP;
1151 			ptcwakeup(tp, FREAD);
1152 		}
1153 	} else {
1154 		if (!stop) {
1155 			pti->pt_send &= ~TIOCPKT_DOSTOP;
1156 			pti->pt_send |= TIOCPKT_NOSTOP;
1157 			pti->pt_flags |= PF_NOSTOP;
1158 			ptcwakeup(tp, FREAD);
1159 		}
1160 	}
1161 	return (error);
1162 }
1163