xref: /netbsd-src/sys/kern/tty_pty.c (revision 7fa608457b817eca6e0977b37f758ae064f3c99c)
1 /*	$NetBSD: tty_pty.c,v 1.102 2007/11/07 15:56:22 ad 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 1.102 2007/11/07 15:56:22 ad Exp $");
41 
42 #include "opt_compat_sunos.h"
43 #include "opt_ptm.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/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 		MALLOC(pti, struct pt_softc *, sizeof(struct pt_softc),
234 			M_DEVBUF, M_WAITOK);
235 		memset(pti, 0, sizeof(struct pt_softc));
236 
237 	 	pti->pt_tty = ttymalloc();
238 
239 		mutex_enter(&pt_softc_mutex);
240 
241 		/*
242 		 * Check the entry again - it might have been
243 		 * added while we were waiting for mutex.
244 		 */
245 		if (!pt_softc[ptn]) {
246 			tty_attach(pti->pt_tty);
247 			pt_softc[ptn] = pti;
248 		} else {
249 			ttyfree(pti->pt_tty);
250 			free(pti, M_DEVBUF);
251 		}
252 
253 		mutex_exit(&pt_softc_mutex);
254 	}
255 
256 	return (0);
257 }
258 
259 /*
260  * Set maxpty in thread-safe way. Returns 0 in case of error, otherwise
261  * new value of maxptys.
262  */
263 int
264 pty_maxptys(newmax, set)
265 	int newmax, set;
266 {
267 	if (!set)
268 		return (maxptys);
269 
270 	/*
271 	 * We have to grab the pt_softc lock, so that we would pick correct
272 	 * value of npty (might be modified in pty_check()).
273 	 */
274 	mutex_enter(&pt_softc_mutex);
275 
276 	/*
277 	 * The value cannot be set to value lower than the highest pty
278 	 * number ever allocated.
279 	 */
280 	if (newmax >= npty)
281 		maxptys = newmax;
282 	else
283 		newmax = 0;
284 
285 	mutex_exit(&pt_softc_mutex);
286 
287 	return newmax;
288 }
289 
290 /*
291  * Establish n (or default if n is 1) ptys in the system.
292  */
293 void
294 ptyattach(n)
295 	int n;
296 {
297 
298 	mutex_init(&pt_softc_mutex, MUTEX_DEFAULT, IPL_NONE);
299 
300 	/* maybe should allow 0 => none? */
301 	if (n <= 1)
302 		n = DEFAULT_NPTYS;
303 	pt_softc = ptyarralloc(n);
304 	npty = n;
305 #ifndef NO_DEV_PTM
306 	ptmattach(1);
307 #endif
308 }
309 
310 /*ARGSUSED*/
311 int
312 ptsopen(dev_t dev, int flag, int devtype, struct lwp *l)
313 {
314 	struct pt_softc *pti;
315 	struct tty *tp;
316 	int error;
317 	int ptn = minor(dev);
318 
319 	if ((error = pty_check(ptn)) != 0)
320 		return (error);
321 
322 	pti = pt_softc[ptn];
323 	tp = pti->pt_tty;
324 
325 	if (!ISSET(tp->t_state, TS_ISOPEN)) {
326 		ttychars(tp);		/* Set up default chars */
327 		tp->t_iflag = TTYDEF_IFLAG;
328 		tp->t_oflag = TTYDEF_OFLAG;
329 		tp->t_lflag = TTYDEF_LFLAG;
330 		tp->t_cflag = TTYDEF_CFLAG;
331 		tp->t_ispeed = tp->t_ospeed = TTYDEF_SPEED;
332 		ttsetwater(tp);		/* would be done in xxparam() */
333 	} else if (kauth_authorize_device_tty(l->l_cred, KAUTH_DEVICE_TTY_OPEN,
334 	    tp) != 0)
335 		return (EBUSY);
336 	if (tp->t_oproc)			/* Ctrlr still around. */
337 		SET(tp->t_state, TS_CARR_ON);
338 
339 	if (!ISSET(flag, O_NONBLOCK)) {
340 		mutex_spin_enter(&tty_lock);
341 		while (!ISSET(tp->t_state, TS_CARR_ON)) {
342 			tp->t_wopen++;
343 			error = ttysleep(tp, &tp->t_rawq.c_cv, true, 0);
344 			tp->t_wopen--;
345 			if (error) {
346 				mutex_spin_exit(&tty_lock);
347 				return (error);
348 			}
349 		}
350 		mutex_spin_exit(&tty_lock);
351 	}
352 	error = (*tp->t_linesw->l_open)(dev, tp);
353 	ptcwakeup(tp, FREAD|FWRITE);
354 	return (error);
355 }
356 
357 int
358 ptsclose(dev_t dev, int flag, int mode, struct lwp *l)
359 {
360 	struct pt_softc *pti = pt_softc[minor(dev)];
361 	struct tty *tp = pti->pt_tty;
362 	int error;
363 
364 	error = (*tp->t_linesw->l_close)(tp, flag);
365 	error |= ttyclose(tp);
366 	ptcwakeup(tp, FREAD|FWRITE);
367 	return (error);
368 }
369 
370 int
371 ptsread(dev, uio, flag)
372 	dev_t dev;
373 	struct uio *uio;
374 	int flag;
375 {
376 	struct proc *p = curproc;
377 	struct pt_softc *pti = pt_softc[minor(dev)];
378 	struct tty *tp = pti->pt_tty;
379 	int error = 0;
380 	int cc;
381 
382 again:
383 	if (pti->pt_flags & PF_REMOTE) {
384 		while (isbackground(p, tp)) {	/* XXXSMP */
385 			if (sigismasked(curlwp, SIGTTIN) ||
386 			    p->p_pgrp->pg_jobc == 0 ||
387 			    p->p_flag & PS_PPWAIT)
388 				return (EIO);
389 			mutex_spin_enter(&tty_lock);
390 			ttysig(tp, TTYSIG_PG1, SIGTTIN);
391 			error = ttysleep(tp, &lbolt, true, 0);
392 			mutex_spin_exit(&tty_lock);
393 			if (error)
394 				return (error);
395 		}
396 		mutex_spin_enter(&tty_lock);
397 		if (tp->t_canq.c_cc == 0) {
398 			if (flag & IO_NDELAY) {
399 				mutex_spin_exit(&tty_lock);
400 				return (EWOULDBLOCK);
401 			}
402 			error = ttysleep(tp, &tp->t_canq.c_cv, true, 0);
403 			mutex_spin_exit(&tty_lock);
404 			if (error)
405 				return (error);
406 			goto again;
407 		}
408 		while(error == 0 && tp->t_canq.c_cc > 1 && uio->uio_resid > 0) {
409 			mutex_spin_exit(&tty_lock);
410 			error = ureadc(getc(&tp->t_canq), uio);
411 			mutex_spin_enter(&tty_lock);
412 			/* Re-check terminal state here? */
413 		}
414 		if (tp->t_canq.c_cc == 1)
415 			(void) getc(&tp->t_canq);
416 		cc = tp->t_canq.c_cc;
417 		mutex_spin_exit(&tty_lock);
418 		if (cc)
419 			return (error);
420 	} else
421 		if (tp->t_oproc)
422 			error = (*tp->t_linesw->l_read)(tp, uio, flag);
423 	ptcwakeup(tp, FWRITE);
424 	return (error);
425 }
426 
427 /*
428  * Write to pseudo-tty.
429  * Wakeups of controlling tty will happen
430  * indirectly, when tty driver calls ptsstart.
431  */
432 int
433 ptswrite(dev, uio, flag)
434 	dev_t dev;
435 	struct uio *uio;
436 	int flag;
437 {
438 	struct pt_softc *pti = pt_softc[minor(dev)];
439 	struct tty *tp = pti->pt_tty;
440 
441 	if (tp->t_oproc == 0)
442 		return (EIO);
443 	return ((*tp->t_linesw->l_write)(tp, uio, flag));
444 }
445 
446 /*
447  * Poll pseudo-tty.
448  */
449 int
450 ptspoll(dev, events, l)
451 	dev_t dev;
452 	int events;
453 	struct lwp *l;
454 {
455 	struct pt_softc *pti = pt_softc[minor(dev)];
456 	struct tty *tp = pti->pt_tty;
457 
458 	if (tp->t_oproc == 0)
459 		return (POLLHUP);
460 
461 	return ((*tp->t_linesw->l_poll)(tp, events, l));
462 }
463 
464 /*
465  * Start output on pseudo-tty.
466  * Wake up process polling or sleeping for input from controlling tty.
467  * Called with tty lock held.
468  */
469 void
470 ptsstart(tp)
471 	struct tty *tp;
472 {
473 	struct pt_softc *pti = pt_softc[minor(tp->t_dev)];
474 
475 	if (ISSET(tp->t_state, TS_TTSTOP))
476 		return;
477 	if (pti->pt_flags & PF_STOPPED) {
478 		pti->pt_flags &= ~PF_STOPPED;
479 		pti->pt_send = TIOCPKT_START;
480 	}
481 
482 	selnotify(&pti->pt_selr, NOTE_SUBMIT);
483 	cv_broadcast(&tp->t_outq.c_cvf);
484 }
485 
486 /*
487  * Stop output.
488  * Called with tty lock held.
489  */
490 void
491 ptsstop(tp, flush)
492 	struct tty *tp;
493 	int flush;
494 {
495 	struct pt_softc *pti = pt_softc[minor(tp->t_dev)];
496 
497 	/* note: FLUSHREAD and FLUSHWRITE already ok */
498 	if (flush == 0) {
499 		flush = TIOCPKT_STOP;
500 		pti->pt_flags |= PF_STOPPED;
501 	} else
502 		pti->pt_flags &= ~PF_STOPPED;
503 	pti->pt_send |= flush;
504 
505 	/* change of perspective */
506 	if (flush & FREAD) {
507 		selnotify(&pti->pt_selw, NOTE_SUBMIT);
508 		cv_broadcast(&tp->t_rawq.c_cvf);
509 	}
510 	if (flush & FWRITE) {
511 		selnotify(&pti->pt_selr, NOTE_SUBMIT);
512 		cv_broadcast(&tp->t_outq.c_cvf);
513 	}
514 }
515 
516 void
517 ptcwakeup(tp, flag)
518 	struct tty *tp;
519 	int flag;
520 {
521 	struct pt_softc *pti = pt_softc[minor(tp->t_dev)];
522 
523 	mutex_spin_enter(&tty_lock);
524 	if (flag & FREAD) {
525 		selnotify(&pti->pt_selr, NOTE_SUBMIT);
526 		cv_broadcast(&tp->t_outq.c_cvf);
527 	}
528 	if (flag & FWRITE) {
529 		selnotify(&pti->pt_selw, NOTE_SUBMIT);
530 		cv_broadcast(&tp->t_rawq.c_cvf);
531 	}
532 	mutex_spin_exit(&tty_lock);
533 }
534 
535 /*ARGSUSED*/
536 int
537 ptcopen(dev_t dev, int flag, int devtype, struct lwp *l)
538 {
539 	struct pt_softc *pti;
540 	struct tty *tp;
541 	int error;
542 	int ptn = minor(dev);
543 
544 	if ((error = pty_check(ptn)) != 0)
545 		return (error);
546 
547 	pti = pt_softc[ptn];
548 	tp = pti->pt_tty;
549 
550 	mutex_spin_enter(&tty_lock);
551 	if (tp->t_oproc) {
552 		mutex_spin_exit(&tty_lock);
553 		return (EIO);
554 	}
555 	tp->t_oproc = ptsstart;
556 	mutex_spin_exit(&tty_lock);
557 	(void)(*tp->t_linesw->l_modem)(tp, 1);
558 	CLR(tp->t_lflag, EXTPROC);
559 	pti->pt_flags = 0;
560 	pti->pt_send = 0;
561 	pti->pt_ucntl = 0;
562 	return (0);
563 }
564 
565 /*ARGSUSED*/
566 int
567 ptcclose(dev_t dev, int flag, int devtype, struct lwp *l)
568 {
569 	struct pt_softc *pti = pt_softc[minor(dev)];
570 	struct tty *tp = pti->pt_tty;
571 
572 	(void)(*tp->t_linesw->l_modem)(tp, 0);
573 	CLR(tp->t_state, TS_CARR_ON);
574 	mutex_spin_enter(&tty_lock);
575 	tp->t_oproc = 0;		/* mark closed */
576 	mutex_spin_exit(&tty_lock);
577 	return (0);
578 }
579 
580 int
581 ptcread(dev, uio, flag)
582 	dev_t dev;
583 	struct uio *uio;
584 	int flag;
585 {
586 	struct pt_softc *pti = pt_softc[minor(dev)];
587 	struct tty *tp = pti->pt_tty;
588 	u_char bf[BUFSIZ];
589 	int error = 0, cc;
590 
591 	/*
592 	 * We want to block until the slave
593 	 * is open, and there's something to read;
594 	 * but if we lost the slave or we're NBIO,
595 	 * then return the appropriate error instead.
596 	 */
597 	mutex_spin_enter(&tty_lock);
598 	for (;;) {
599 		if (ISSET(tp->t_state, TS_ISOPEN)) {
600 			if (pti->pt_flags & PF_PKT && pti->pt_send) {
601 				mutex_spin_exit(&tty_lock);
602 				error = ureadc((int)pti->pt_send, uio);
603 				if (error)
604 					return (error);
605 				/*
606 				 * Since we don't have the tty locked, there's
607 				 * a risk of messing up `t_termios'. This is
608 				 * relevant only if the tty got closed and then
609 				 * opened again while we were out uiomoving.
610 				 */
611 				if (pti->pt_send & TIOCPKT_IOCTL) {
612 					cc = min(uio->uio_resid,
613 						sizeof(tp->t_termios));
614 					uiomove((void *) &tp->t_termios,
615 						cc, uio);
616 				}
617 				pti->pt_send = 0;
618 				return (0);
619 			}
620 			if (pti->pt_flags & PF_UCNTL && pti->pt_ucntl) {
621 				mutex_spin_exit(&tty_lock);
622 				error = ureadc((int)pti->pt_ucntl, uio);
623 				if (error)
624 					return (error);
625 				pti->pt_ucntl = 0;
626 				return (0);
627 			}
628 			if (tp->t_outq.c_cc && !ISSET(tp->t_state, TS_TTSTOP))
629 				break;
630 		}
631 		if (!ISSET(tp->t_state, TS_CARR_ON)) {
632 			error = 0;	/* EOF */
633 			goto out;
634 		}
635 		if (flag & IO_NDELAY) {
636 			error = EWOULDBLOCK;
637 			goto out;
638 		}
639 		error = cv_wait_sig(&tp->t_outq.c_cvf, &tty_lock);
640 		if (error)
641 			goto out;
642 	}
643 
644 	if (pti->pt_flags & (PF_PKT|PF_UCNTL)) {
645 		mutex_spin_exit(&tty_lock);
646 		error = ureadc(0, uio);
647 		mutex_spin_enter(&tty_lock);
648 		if (error == 0 && !ISSET(tp->t_state, TS_ISOPEN))
649 			error = EIO;
650 	}
651 	while (uio->uio_resid > 0 && error == 0) {
652 		cc = q_to_b(&tp->t_outq, bf, min(uio->uio_resid, BUFSIZ));
653 		if (cc <= 0)
654 			break;
655 		mutex_spin_exit(&tty_lock);
656 		error = uiomove(bf, cc, uio);
657 		mutex_spin_enter(&tty_lock);
658 		if (error == 0 && !ISSET(tp->t_state, TS_ISOPEN))
659 			error = EIO;
660 	}
661 
662 	if (tp->t_outq.c_cc <= tp->t_lowat) {
663 		if (ISSET(tp->t_state, TS_ASLEEP)) {
664 			CLR(tp->t_state, TS_ASLEEP);
665 			cv_broadcast(&tp->t_outq.c_cv);
666 		}
667 		selnotify(&tp->t_wsel, NOTE_SUBMIT);
668 	}
669 out:
670 	mutex_spin_exit(&tty_lock);
671 	return (error);
672 }
673 
674 
675 int
676 ptcwrite(dev, uio, flag)
677 	dev_t dev;
678 	struct uio *uio;
679 	int flag;
680 {
681 	struct pt_softc *pti = pt_softc[minor(dev)];
682 	struct tty *tp = pti->pt_tty;
683 	u_char *cp = NULL;
684 	int cc = 0;
685 	u_char locbuf[BUFSIZ];
686 	int cnt = 0;
687 	int error = 0;
688 
689 again:
690 	mutex_spin_enter(&tty_lock);
691 	if (!ISSET(tp->t_state, TS_ISOPEN))
692 		goto block;
693 	if (pti->pt_flags & PF_REMOTE) {
694 		if (tp->t_canq.c_cc)
695 			goto block;
696 		while (uio->uio_resid > 0 && tp->t_canq.c_cc < TTYHOG - 1) {
697 			if (cc == 0) {
698 				cc = min(uio->uio_resid, BUFSIZ);
699 				cc = min(cc, TTYHOG - 1 - tp->t_canq.c_cc);
700 				cp = locbuf;
701 				mutex_spin_exit(&tty_lock);
702 				error = uiomove((void *)cp, cc, uio);
703 				if (error)
704 					return (error);
705 				mutex_spin_enter(&tty_lock);
706 				/* check again for safety */
707 				if (!ISSET(tp->t_state, TS_ISOPEN)) {
708 					/*
709 					 * adjust for data copied in but not
710 					 * written
711 					 */
712 					uio->uio_resid += cc;
713 					error = EIO;
714 					goto out;
715 				}
716 			}
717 			if (cc)
718 				(void) b_to_q(cp, cc, &tp->t_canq);
719 			cc = 0;
720 		}
721 		(void) putc(0, &tp->t_canq);
722 		ttwakeup(tp);
723 		cv_broadcast(&tp->t_canq.c_cv);
724 		error = 0;
725 		goto out;
726 	}
727 	while (uio->uio_resid > 0) {
728 		if (cc == 0) {
729 			cc = min(uio->uio_resid, BUFSIZ);
730 			cp = locbuf;
731 			mutex_spin_exit(&tty_lock);
732 			error = uiomove((void *)cp, cc, uio);
733 			if (error)
734 				return (error);
735 			mutex_spin_enter(&tty_lock);
736 			/* check again for safety */
737 			if (!ISSET(tp->t_state, TS_ISOPEN)) {
738 				/* adjust for data copied in but not written */
739 				uio->uio_resid += cc;
740 				error = EIO;
741 				goto out;
742 			}
743 		}
744 		while (cc > 0) {
745 			if ((tp->t_rawq.c_cc + tp->t_canq.c_cc) >= TTYHOG - 2 &&
746 			   (tp->t_canq.c_cc > 0 || !ISSET(tp->t_lflag, ICANON))) {
747 				cv_broadcast(&tp->t_rawq.c_cv);
748 				goto block;
749 			}
750 			/* XXX - should change l_rint to be called with lock
751 			 *	 see also tty.c:ttyinput_wlock()
752 			 */
753 			mutex_spin_exit(&tty_lock);
754 			(*tp->t_linesw->l_rint)(*cp++, tp);
755 			mutex_spin_enter(&tty_lock);
756 			cnt++;
757 			cc--;
758 		}
759 		cc = 0;
760 	}
761 	error = 0;
762 	goto out;
763 
764 block:
765 	/*
766 	 * Come here to wait for slave to open, for space
767 	 * in outq, or space in rawq.
768 	 */
769 	if (!ISSET(tp->t_state, TS_CARR_ON)) {
770 		/* adjust for data copied in but not written */
771 		uio->uio_resid += cc;
772 		error = EIO;
773 		goto out;
774 	}
775 	if (flag & IO_NDELAY) {
776 		/* adjust for data copied in but not written */
777 		uio->uio_resid += cc;
778 		error = cnt == 0 ? EWOULDBLOCK : 0;
779 		goto out;
780 	}
781 	error = cv_wait_sig(&tp->t_rawq.c_cv, &tty_lock);
782 	mutex_spin_exit(&tty_lock);
783 	if (error) {
784 		/* adjust for data copied in but not written */
785 		uio->uio_resid += cc;
786 		return (error);
787 	}
788 	goto again;
789 
790 out:
791 	mutex_spin_exit(&tty_lock);
792 	return (error);
793 }
794 
795 int
796 ptcpoll(dev, events, l)
797 	dev_t dev;
798 	int events;
799 	struct lwp *l;
800 {
801 	struct pt_softc *pti = pt_softc[minor(dev)];
802 	struct tty *tp = pti->pt_tty;
803 	int revents = 0;
804 
805 	mutex_spin_enter(&tty_lock);
806 
807 	if (events & (POLLIN | POLLRDNORM))
808 		if (ISSET(tp->t_state, TS_ISOPEN) &&
809 		    ((tp->t_outq.c_cc > 0 && !ISSET(tp->t_state, TS_TTSTOP)) ||
810 		     ((pti->pt_flags & PF_PKT) && pti->pt_send) ||
811 		     ((pti->pt_flags & PF_UCNTL) && pti->pt_ucntl)))
812 			revents |= events & (POLLIN | POLLRDNORM);
813 
814 	if (events & (POLLOUT | POLLWRNORM))
815 		if (ISSET(tp->t_state, TS_ISOPEN) &&
816 		    ((pti->pt_flags & PF_REMOTE) ?
817 		     (tp->t_canq.c_cc == 0) :
818 		     ((tp->t_rawq.c_cc + tp->t_canq.c_cc < TTYHOG-2) ||
819 		      (tp->t_canq.c_cc == 0 && ISSET(tp->t_lflag, ICANON)))))
820 			revents |= events & (POLLOUT | POLLWRNORM);
821 
822 	if (events & POLLHUP)
823 		if (!ISSET(tp->t_state, TS_CARR_ON))
824 			revents |= POLLHUP;
825 
826 	if (revents == 0) {
827 		if (events & (POLLIN | POLLHUP | POLLRDNORM))
828 			selrecord(l, &pti->pt_selr);
829 
830 		if (events & (POLLOUT | POLLWRNORM))
831 			selrecord(l, &pti->pt_selw);
832 	}
833 
834 	mutex_spin_exit(&tty_lock);
835 
836 	return (revents);
837 }
838 
839 static void
840 filt_ptcrdetach(struct knote *kn)
841 {
842 	struct pt_softc *pti;
843 	struct tty	*tp;
844 
845 	pti = kn->kn_hook;
846 	tp = pti->pt_tty;
847 
848 	mutex_spin_enter(&tty_lock);
849 	SLIST_REMOVE(&pti->pt_selr.sel_klist, kn, knote, kn_selnext);
850 	mutex_spin_exit(&tty_lock);
851 }
852 
853 static int
854 filt_ptcread(struct knote *kn, long hint)
855 {
856 	struct pt_softc *pti;
857 	struct tty	*tp;
858 	int canread;
859 
860 	pti = kn->kn_hook;
861 	tp = pti->pt_tty;
862 
863 	mutex_spin_enter(&tty_lock);
864 
865 	canread = (ISSET(tp->t_state, TS_ISOPEN) &&
866 		    ((tp->t_outq.c_cc > 0 && !ISSET(tp->t_state, TS_TTSTOP)) ||
867 		     ((pti->pt_flags & PF_PKT) && pti->pt_send) ||
868 		     ((pti->pt_flags & PF_UCNTL) && pti->pt_ucntl)));
869 
870 	if (canread) {
871 		/*
872 		 * c_cc is number of characters after output post-processing;
873 		 * the amount of data actually read(2) depends on
874 		 * setting of input flags for the terminal.
875 		 */
876 		kn->kn_data = tp->t_outq.c_cc;
877 		if (((pti->pt_flags & PF_PKT) && pti->pt_send) ||
878 		    ((pti->pt_flags & PF_UCNTL) && pti->pt_ucntl))
879 			kn->kn_data++;
880 	}
881 
882 	mutex_spin_exit(&tty_lock);
883 
884 	return (canread);
885 }
886 
887 static void
888 filt_ptcwdetach(struct knote *kn)
889 {
890 	struct pt_softc *pti;
891 	struct tty	*tp;
892 
893 	pti = kn->kn_hook;
894 	tp = pti->pt_tty;
895 
896 	mutex_spin_enter(&tty_lock);
897 	SLIST_REMOVE(&pti->pt_selw.sel_klist, kn, knote, kn_selnext);
898 	mutex_spin_exit(&tty_lock);
899 }
900 
901 static int
902 filt_ptcwrite(struct knote *kn, long hint)
903 {
904 	struct pt_softc *pti;
905 	struct tty	*tp;
906 	int canwrite;
907 	int nwrite;
908 
909 	pti = kn->kn_hook;
910 	tp = pti->pt_tty;
911 
912 	mutex_spin_enter(&tty_lock);
913 
914 	canwrite = (ISSET(tp->t_state, TS_ISOPEN) &&
915 		    ((pti->pt_flags & PF_REMOTE) ?
916 		     (tp->t_canq.c_cc == 0) :
917 		     ((tp->t_rawq.c_cc + tp->t_canq.c_cc < TTYHOG-2) ||
918 		      (tp->t_canq.c_cc == 0 && ISSET(tp->t_lflag, ICANON)))));
919 
920 	if (canwrite) {
921 		if (pti->pt_flags & PF_REMOTE)
922 			nwrite = tp->t_canq.c_cn;
923 		else {
924 			/* this is guaranteed to be > 0 due to above check */
925 			nwrite = tp->t_canq.c_cn
926 				- (tp->t_rawq.c_cc + tp->t_canq.c_cc);
927 		}
928 		kn->kn_data = nwrite;
929 	}
930 
931 	mutex_spin_exit(&tty_lock);
932 
933 	return (canwrite);
934 }
935 
936 static const struct filterops ptcread_filtops =
937 	{ 1, NULL, filt_ptcrdetach, filt_ptcread };
938 static const struct filterops ptcwrite_filtops =
939 	{ 1, NULL, filt_ptcwdetach, filt_ptcwrite };
940 
941 int
942 ptckqfilter(dev_t dev, struct knote *kn)
943 {
944 	struct pt_softc *pti = pt_softc[minor(dev)];
945 	struct klist	*klist;
946 
947 	switch (kn->kn_filter) {
948 	case EVFILT_READ:
949 		klist = &pti->pt_selr.sel_klist;
950 		kn->kn_fop = &ptcread_filtops;
951 		break;
952 	case EVFILT_WRITE:
953 		klist = &pti->pt_selw.sel_klist;
954 		kn->kn_fop = &ptcwrite_filtops;
955 		break;
956 	default:
957 		return (1);
958 	}
959 
960 	kn->kn_hook = pti;
961 
962 	mutex_spin_enter(&tty_lock);
963 	SLIST_INSERT_HEAD(klist, kn, kn_selnext);
964 	mutex_spin_exit(&tty_lock);
965 
966 	return (0);
967 }
968 
969 struct tty *
970 ptytty(dev)
971 	dev_t dev;
972 {
973 	struct pt_softc *pti = pt_softc[minor(dev)];
974 	struct tty *tp = pti->pt_tty;
975 
976 	return (tp);
977 }
978 
979 /*ARGSUSED*/
980 int
981 ptyioctl(dev, cmd, data, flag, l)
982 	dev_t dev;
983 	u_long cmd;
984 	void *data;
985 	int flag;
986 	struct lwp *l;
987 {
988 	struct pt_softc *pti = pt_softc[minor(dev)];
989 	struct tty *tp = pti->pt_tty;
990 	const struct cdevsw *cdev;
991 	u_char *cc = tp->t_cc;
992 	int stop, error, sig;
993 
994 	/*
995 	 * IF CONTROLLER STTY THEN MUST FLUSH TO PREVENT A HANG.
996 	 * ttywflush(tp) will hang if there are characters in the outq.
997 	 */
998 	if (cmd == TIOCEXT) {
999 		/*
1000 		 * When the EXTPROC bit is being toggled, we need
1001 		 * to send an TIOCPKT_IOCTL if the packet driver
1002 		 * is turned on.
1003 		 */
1004 		if (*(int *)data) {
1005 			if (pti->pt_flags & PF_PKT) {
1006 				pti->pt_send |= TIOCPKT_IOCTL;
1007 				ptcwakeup(tp, FREAD);
1008 			}
1009 			SET(tp->t_lflag, EXTPROC);
1010 		} else {
1011 			if (ISSET(tp->t_lflag, EXTPROC) &&
1012 			    (pti->pt_flags & PF_PKT)) {
1013 				pti->pt_send |= TIOCPKT_IOCTL;
1014 				ptcwakeup(tp, FREAD);
1015 			}
1016 			CLR(tp->t_lflag, EXTPROC);
1017 		}
1018 		return(0);
1019 	}
1020 
1021 #ifndef NO_DEV_PTM
1022 	/* Allow getting the name from either the master or the slave */
1023 	if (cmd == TIOCPTSNAME)
1024 		return pty_fill_ptmget(l, dev, -1, -1, data);
1025 #endif
1026 
1027 	cdev = cdevsw_lookup(dev);
1028 	if (cdev != NULL && cdev->d_open == ptcopen)
1029 		switch (cmd) {
1030 #ifndef NO_DEV_PTM
1031 		case TIOCGRANTPT:
1032 			return pty_grant_slave(l, dev);
1033 #endif
1034 
1035 		case TIOCGPGRP:
1036 			/*
1037 			 * We avoid calling ttioctl on the controller since,
1038 			 * in that case, tp must be the controlling terminal.
1039 			 */
1040 			*(int *)data = tp->t_pgrp ? tp->t_pgrp->pg_id : 0;
1041 			return (0);
1042 
1043 		case TIOCPKT:
1044 			if (*(int *)data) {
1045 				if (pti->pt_flags & PF_UCNTL)
1046 					return (EINVAL);
1047 				pti->pt_flags |= PF_PKT;
1048 			} else
1049 				pti->pt_flags &= ~PF_PKT;
1050 			return (0);
1051 
1052 		case TIOCUCNTL:
1053 			if (*(int *)data) {
1054 				if (pti->pt_flags & PF_PKT)
1055 					return (EINVAL);
1056 				pti->pt_flags |= PF_UCNTL;
1057 			} else
1058 				pti->pt_flags &= ~PF_UCNTL;
1059 			return (0);
1060 
1061 		case TIOCREMOTE:
1062 			if (*(int *)data)
1063 				pti->pt_flags |= PF_REMOTE;
1064 			else
1065 				pti->pt_flags &= ~PF_REMOTE;
1066 			mutex_spin_enter(&tty_lock);
1067 			ttyflush(tp, FREAD|FWRITE);
1068 			mutex_spin_exit(&tty_lock);
1069 			return (0);
1070 
1071 #ifdef COMPAT_OLDTTY
1072 		case TIOCSETP:
1073 		case TIOCSETN:
1074 #endif
1075 		case TIOCSETD:
1076 		case TIOCSETA:
1077 		case TIOCSETAW:
1078 		case TIOCSETAF:
1079 			mutex_spin_enter(&tty_lock);
1080 			ndflush(&tp->t_outq, tp->t_outq.c_cc);
1081 			mutex_spin_exit(&tty_lock);
1082 			break;
1083 
1084 		case TIOCSIG:
1085 			sig = (int)(long)*(void **)data;
1086 			if (sig <= 0 || sig >= NSIG)
1087 				return (EINVAL);
1088 			mutex_spin_enter(&tty_lock);
1089 			if (!ISSET(tp->t_lflag, NOFLSH))
1090 				ttyflush(tp, FREAD|FWRITE);
1091 			if ((sig == SIGINFO) &&
1092 			    (!ISSET(tp->t_lflag, NOKERNINFO)))
1093 				ttyinfo(tp, 1);
1094 			ttysig(tp, TTYSIG_PG1, sig);
1095 			mutex_spin_exit(&tty_lock);
1096 			return(0);
1097 		}
1098 
1099 	error = (*tp->t_linesw->l_ioctl)(tp, cmd, data, flag, l);
1100 	if (error == EPASSTHROUGH)
1101 		 error = ttioctl(tp, cmd, data, flag, l);
1102 	if (error == EPASSTHROUGH) {
1103 		if (pti->pt_flags & PF_UCNTL &&
1104 		    (cmd & ~0xff) == UIOCCMD(0)) {
1105 			if (cmd & 0xff) {
1106 				pti->pt_ucntl = (u_char)cmd;
1107 				ptcwakeup(tp, FREAD);
1108 			}
1109 			return (0);
1110 		}
1111 	}
1112 	/*
1113 	 * If external processing and packet mode send ioctl packet.
1114 	 */
1115 	if (ISSET(tp->t_lflag, EXTPROC) && (pti->pt_flags & PF_PKT)) {
1116 		switch(cmd) {
1117 		case TIOCSETA:
1118 		case TIOCSETAW:
1119 		case TIOCSETAF:
1120 #ifdef COMPAT_OLDTTY
1121 		case TIOCSETP:
1122 		case TIOCSETN:
1123 		case TIOCSETC:
1124 		case TIOCSLTC:
1125 		case TIOCLBIS:
1126 		case TIOCLBIC:
1127 		case TIOCLSET:
1128 #endif
1129 			pti->pt_send |= TIOCPKT_IOCTL;
1130 			ptcwakeup(tp, FREAD);
1131 		default:
1132 			break;
1133 		}
1134 	}
1135 	stop = ISSET(tp->t_iflag, IXON) && CCEQ(cc[VSTOP], CTRL('s'))
1136 		&& CCEQ(cc[VSTART], CTRL('q'));
1137 	if (pti->pt_flags & PF_NOSTOP) {
1138 		if (stop) {
1139 			pti->pt_send &= ~TIOCPKT_NOSTOP;
1140 			pti->pt_send |= TIOCPKT_DOSTOP;
1141 			pti->pt_flags &= ~PF_NOSTOP;
1142 			ptcwakeup(tp, FREAD);
1143 		}
1144 	} else {
1145 		if (!stop) {
1146 			pti->pt_send &= ~TIOCPKT_DOSTOP;
1147 			pti->pt_send |= TIOCPKT_NOSTOP;
1148 			pti->pt_flags |= PF_NOSTOP;
1149 			ptcwakeup(tp, FREAD);
1150 		}
1151 	}
1152 	return (error);
1153 }
1154