xref: /netbsd-src/sys/kern/tty_pty.c (revision 8b0f9554ff8762542c4defc4f70e1eb76fb508fa)
1 /*	$NetBSD: tty_pty.c,v 1.105 2007/12/05 17:19:58 pooka 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 1.105 2007/12/05 17:19:58 pooka 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 	mutex_spin_enter(&tty_lock);
323 	pti = pt_softc[ptn];
324 	tp = pti->pt_tty;
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 		mutex_spin_exit(&tty_lock);
336 		return (EBUSY);
337 	}
338 	if (tp->t_oproc)			/* Ctrlr still around. */
339 		SET(tp->t_state, TS_CARR_ON);
340 	if (!ISSET(flag, O_NONBLOCK)) {
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 	}
351 	mutex_spin_exit(&tty_lock);
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, c;
381 
382 again:
383 	if (pti->pt_flags & PF_REMOTE) {
384 		mutex_spin_enter(&tty_lock);
385 		while (isbackground(p, tp)) {	/* XXXSMP */
386 			if (sigismasked(curlwp, SIGTTIN) ||
387 			    p->p_pgrp->pg_jobc == 0 ||
388 			    p->p_flag & PS_PPWAIT) {
389 				mutex_spin_exit(&tty_lock);
390 				return (EIO);
391 			}
392 			ttysig(tp, TTYSIG_PG1, SIGTTIN);
393 			error = ttysleep(tp, &lbolt, true, 0);
394 			if (error) {
395 				mutex_spin_exit(&tty_lock);
396 				return (error);
397 			}
398 		}
399 		if (tp->t_canq.c_cc == 0) {
400 			if (flag & IO_NDELAY) {
401 				mutex_spin_exit(&tty_lock);
402 				return (EWOULDBLOCK);
403 			}
404 			error = ttysleep(tp, &tp->t_canq.c_cv, true, 0);
405 			mutex_spin_exit(&tty_lock);
406 			if (error)
407 				return (error);
408 			goto again;
409 		}
410 		while(error == 0 && tp->t_canq.c_cc > 1 && uio->uio_resid > 0) {
411 			c = getc(&tp->t_canq);
412 			mutex_spin_exit(&tty_lock);
413 			error = ureadc(c, uio);
414 			mutex_spin_enter(&tty_lock);
415 			/* Re-check terminal state here? */
416 		}
417 		if (tp->t_canq.c_cc == 1)
418 			(void) getc(&tp->t_canq);
419 		cc = tp->t_canq.c_cc;
420 		mutex_spin_exit(&tty_lock);
421 		if (cc)
422 			return (error);
423 	} else if (tp->t_oproc)
424 		error = (*tp->t_linesw->l_read)(tp, uio, flag);
425 	ptcwakeup(tp, FWRITE);
426 	return (error);
427 }
428 
429 /*
430  * Write to pseudo-tty.
431  * Wakeups of controlling tty will happen
432  * indirectly, when tty driver calls ptsstart.
433  */
434 int
435 ptswrite(dev, uio, flag)
436 	dev_t dev;
437 	struct uio *uio;
438 	int flag;
439 {
440 	struct pt_softc *pti = pt_softc[minor(dev)];
441 	struct tty *tp = pti->pt_tty;
442 
443 	if (tp->t_oproc == 0)
444 		return (EIO);
445 	return ((*tp->t_linesw->l_write)(tp, uio, flag));
446 }
447 
448 /*
449  * Poll pseudo-tty.
450  */
451 int
452 ptspoll(dev, events, l)
453 	dev_t dev;
454 	int events;
455 	struct lwp *l;
456 {
457 	struct pt_softc *pti = pt_softc[minor(dev)];
458 	struct tty *tp = pti->pt_tty;
459 
460 	if (tp->t_oproc == 0)
461 		return (POLLHUP);
462 
463 	return ((*tp->t_linesw->l_poll)(tp, events, l));
464 }
465 
466 /*
467  * Start output on pseudo-tty.
468  * Wake up process polling or sleeping for input from controlling tty.
469  */
470 void
471 ptsstart(tp)
472 	struct tty *tp;
473 {
474 	struct pt_softc *pti = pt_softc[minor(tp->t_dev)];
475 
476 	KASSERT(mutex_owned(&tty_lock));
477 
478 	if (ISSET(tp->t_state, TS_TTSTOP))
479 		return;
480 	if (pti->pt_flags & PF_STOPPED) {
481 		pti->pt_flags &= ~PF_STOPPED;
482 		pti->pt_send = TIOCPKT_START;
483 	}
484 
485 	selnotify(&pti->pt_selr, NOTE_SUBMIT);
486 	clwakeup(&tp->t_outq);
487 }
488 
489 /*
490  * Stop output.
491  */
492 void
493 ptsstop(tp, flush)
494 	struct tty *tp;
495 	int flush;
496 {
497 	struct pt_softc *pti = pt_softc[minor(tp->t_dev)];
498 
499 	KASSERT(mutex_owned(&tty_lock));
500 
501 	/* note: FLUSHREAD and FLUSHWRITE already ok */
502 	if (flush == 0) {
503 		flush = TIOCPKT_STOP;
504 		pti->pt_flags |= PF_STOPPED;
505 	} else
506 		pti->pt_flags &= ~PF_STOPPED;
507 	pti->pt_send |= flush;
508 
509 	/* change of perspective */
510 	if (flush & FREAD) {
511 		selnotify(&pti->pt_selw, NOTE_SUBMIT);
512 		clwakeup(&tp->t_rawq);
513 	}
514 	if (flush & FWRITE) {
515 		selnotify(&pti->pt_selr, NOTE_SUBMIT);
516 		clwakeup(&tp->t_outq);
517 	}
518 }
519 
520 void
521 ptcwakeup(tp, flag)
522 	struct tty *tp;
523 	int flag;
524 {
525 	struct pt_softc *pti = pt_softc[minor(tp->t_dev)];
526 
527 	mutex_spin_enter(&tty_lock);
528 	if (flag & FREAD) {
529 		selnotify(&pti->pt_selr, NOTE_SUBMIT);
530 		clwakeup(&tp->t_outq);
531 	}
532 	if (flag & FWRITE) {
533 		selnotify(&pti->pt_selw, NOTE_SUBMIT);
534 		clwakeup(&tp->t_rawq);
535 	}
536 	mutex_spin_exit(&tty_lock);
537 }
538 
539 /*ARGSUSED*/
540 int
541 ptcopen(dev_t dev, int flag, int devtype, struct lwp *l)
542 {
543 	struct pt_softc *pti;
544 	struct tty *tp;
545 	int error;
546 	int ptn = minor(dev);
547 
548 	if ((error = pty_check(ptn)) != 0)
549 		return (error);
550 
551 	pti = pt_softc[ptn];
552 	tp = pti->pt_tty;
553 
554 	mutex_spin_enter(&tty_lock);
555 	if (tp->t_oproc) {
556 		mutex_spin_exit(&tty_lock);
557 		return (EIO);
558 	}
559 	tp->t_oproc = ptsstart;
560 	mutex_spin_exit(&tty_lock);
561 	(void)(*tp->t_linesw->l_modem)(tp, 1);
562 	CLR(tp->t_lflag, EXTPROC);
563 	pti->pt_flags = 0;
564 	pti->pt_send = 0;
565 	pti->pt_ucntl = 0;
566 	return (0);
567 }
568 
569 /*ARGSUSED*/
570 int
571 ptcclose(dev_t dev, int flag, int devtype, struct lwp *l)
572 {
573 	struct pt_softc *pti = pt_softc[minor(dev)];
574 	struct tty *tp = pti->pt_tty;
575 
576 	(void)(*tp->t_linesw->l_modem)(tp, 0);
577 	mutex_spin_enter(&tty_lock);
578 	CLR(tp->t_state, TS_CARR_ON);
579 	tp->t_oproc = 0;		/* mark closed */
580 	mutex_spin_exit(&tty_lock);
581 	return (0);
582 }
583 
584 int
585 ptcread(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 bf[BUFSIZ];
593 	int error = 0, cc;
594 
595 	/*
596 	 * We want to block until the slave
597 	 * is open, and there's something to read;
598 	 * but if we lost the slave or we're NBIO,
599 	 * then return the appropriate error instead.
600 	 */
601 	mutex_spin_enter(&tty_lock);
602 	for (;;) {
603 		if (ISSET(tp->t_state, TS_ISOPEN)) {
604 			if (pti->pt_flags & PF_PKT && pti->pt_send) {
605 				mutex_spin_exit(&tty_lock);
606 				error = ureadc((int)pti->pt_send, uio);
607 				if (error)
608 					return (error);
609 				/*
610 				 * Since we don't have the tty locked, there's
611 				 * a risk of messing up `t_termios'. This is
612 				 * relevant only if the tty got closed and then
613 				 * opened again while we were out uiomoving.
614 				 */
615 				if (pti->pt_send & TIOCPKT_IOCTL) {
616 					cc = min(uio->uio_resid,
617 						sizeof(tp->t_termios));
618 					uiomove((void *) &tp->t_termios,
619 						cc, uio);
620 				}
621 				pti->pt_send = 0;
622 				return (0);
623 			}
624 			if (pti->pt_flags & PF_UCNTL && pti->pt_ucntl) {
625 				mutex_spin_exit(&tty_lock);
626 				error = ureadc((int)pti->pt_ucntl, uio);
627 				if (error)
628 					return (error);
629 				pti->pt_ucntl = 0;
630 				return (0);
631 			}
632 			if (tp->t_outq.c_cc && !ISSET(tp->t_state, TS_TTSTOP))
633 				break;
634 		}
635 		if (!ISSET(tp->t_state, TS_CARR_ON)) {
636 			error = 0;	/* EOF */
637 			goto out;
638 		}
639 		if (flag & IO_NDELAY) {
640 			error = EWOULDBLOCK;
641 			goto out;
642 		}
643 		error = cv_wait_sig(&tp->t_outq.c_cv, &tty_lock);
644 		if (error)
645 			goto out;
646 	}
647 
648 	if (pti->pt_flags & (PF_PKT|PF_UCNTL)) {
649 		mutex_spin_exit(&tty_lock);
650 		error = ureadc(0, uio);
651 		mutex_spin_enter(&tty_lock);
652 		if (error == 0 && !ISSET(tp->t_state, TS_ISOPEN))
653 			error = EIO;
654 	}
655 	while (uio->uio_resid > 0 && error == 0) {
656 		cc = q_to_b(&tp->t_outq, bf, min(uio->uio_resid, BUFSIZ));
657 		if (cc <= 0)
658 			break;
659 		mutex_spin_exit(&tty_lock);
660 		error = uiomove(bf, cc, uio);
661 		mutex_spin_enter(&tty_lock);
662 		if (error == 0 && !ISSET(tp->t_state, TS_ISOPEN))
663 			error = EIO;
664 	}
665 	ttypull(tp);
666 out:
667 	mutex_spin_exit(&tty_lock);
668 	return (error);
669 }
670 
671 
672 int
673 ptcwrite(dev, uio, flag)
674 	dev_t dev;
675 	struct uio *uio;
676 	int flag;
677 {
678 	struct pt_softc *pti = pt_softc[minor(dev)];
679 	struct tty *tp = pti->pt_tty;
680 	u_char *cp = NULL;
681 	int cc = 0;
682 	u_char locbuf[BUFSIZ];
683 	int cnt = 0;
684 	int error = 0;
685 
686 again:
687 	mutex_spin_enter(&tty_lock);
688 	if (!ISSET(tp->t_state, TS_ISOPEN))
689 		goto block;
690 	if (pti->pt_flags & PF_REMOTE) {
691 		if (tp->t_canq.c_cc)
692 			goto block;
693 		while (uio->uio_resid > 0 && tp->t_canq.c_cc < TTYHOG - 1) {
694 			if (cc == 0) {
695 				cc = min(uio->uio_resid, BUFSIZ);
696 				cc = min(cc, TTYHOG - 1 - tp->t_canq.c_cc);
697 				cp = locbuf;
698 				mutex_spin_exit(&tty_lock);
699 				error = uiomove((void *)cp, cc, uio);
700 				if (error)
701 					return (error);
702 				mutex_spin_enter(&tty_lock);
703 				/* check again for safety */
704 				if (!ISSET(tp->t_state, TS_ISOPEN)) {
705 					/*
706 					 * adjust for data copied in but not
707 					 * written
708 					 */
709 					uio->uio_resid += cc;
710 					error = EIO;
711 					goto out;
712 				}
713 			}
714 			if (cc)
715 				(void) b_to_q(cp, cc, &tp->t_canq);
716 			cc = 0;
717 		}
718 		(void) putc(0, &tp->t_canq);
719 		ttwakeup(tp);
720 		clwakeup(&tp->t_canq);
721 		error = 0;
722 		goto out;
723 	}
724 	while (uio->uio_resid > 0) {
725 		if (cc == 0) {
726 			cc = min(uio->uio_resid, BUFSIZ);
727 			cp = locbuf;
728 			mutex_spin_exit(&tty_lock);
729 			error = uiomove((void *)cp, cc, uio);
730 			if (error)
731 				return (error);
732 			mutex_spin_enter(&tty_lock);
733 			/* check again for safety */
734 			if (!ISSET(tp->t_state, TS_ISOPEN)) {
735 				/* adjust for data copied in but not written */
736 				uio->uio_resid += cc;
737 				error = EIO;
738 				goto out;
739 			}
740 		}
741 		while (cc > 0) {
742 			if ((tp->t_rawq.c_cc + tp->t_canq.c_cc) >= TTYHOG - 2 &&
743 			   (tp->t_canq.c_cc > 0 || !ISSET(tp->t_lflag, ICANON))) {
744 				clwakeup(&tp->t_rawq);
745 				goto block;
746 			}
747 			/* XXX - should change l_rint to be called with lock
748 			 *	 see also tty.c:ttyinput_wlock()
749 			 */
750 			mutex_spin_exit(&tty_lock);
751 			(*tp->t_linesw->l_rint)(*cp++, tp);
752 			mutex_spin_enter(&tty_lock);
753 			cnt++;
754 			cc--;
755 		}
756 		cc = 0;
757 	}
758 	error = 0;
759 	goto out;
760 
761 block:
762 	/*
763 	 * Come here to wait for slave to open, for space
764 	 * in outq, or space in rawq.
765 	 */
766 	if (!ISSET(tp->t_state, TS_CARR_ON)) {
767 		/* adjust for data copied in but not written */
768 		uio->uio_resid += cc;
769 		error = EIO;
770 		goto out;
771 	}
772 	if (flag & IO_NDELAY) {
773 		/* adjust for data copied in but not written */
774 		uio->uio_resid += cc;
775 		error = cnt == 0 ? EWOULDBLOCK : 0;
776 		goto out;
777 	}
778 	error = cv_wait_sig(&tp->t_rawq.c_cv, &tty_lock);
779 	mutex_spin_exit(&tty_lock);
780 	if (error) {
781 		/* adjust for data copied in but not written */
782 		uio->uio_resid += cc;
783 		return (error);
784 	}
785 	goto again;
786 
787 out:
788 	mutex_spin_exit(&tty_lock);
789 	return (error);
790 }
791 
792 int
793 ptcpoll(dev, events, l)
794 	dev_t dev;
795 	int events;
796 	struct lwp *l;
797 {
798 	struct pt_softc *pti = pt_softc[minor(dev)];
799 	struct tty *tp = pti->pt_tty;
800 	int revents = 0;
801 
802 	mutex_spin_enter(&tty_lock);
803 
804 	if (events & (POLLIN | POLLRDNORM))
805 		if (ISSET(tp->t_state, TS_ISOPEN) &&
806 		    ((tp->t_outq.c_cc > 0 && !ISSET(tp->t_state, TS_TTSTOP)) ||
807 		     ((pti->pt_flags & PF_PKT) && pti->pt_send) ||
808 		     ((pti->pt_flags & PF_UCNTL) && pti->pt_ucntl)))
809 			revents |= events & (POLLIN | POLLRDNORM);
810 
811 	if (events & (POLLOUT | POLLWRNORM))
812 		if (ISSET(tp->t_state, TS_ISOPEN) &&
813 		    ((pti->pt_flags & PF_REMOTE) ?
814 		     (tp->t_canq.c_cc == 0) :
815 		     ((tp->t_rawq.c_cc + tp->t_canq.c_cc < TTYHOG-2) ||
816 		      (tp->t_canq.c_cc == 0 && ISSET(tp->t_lflag, ICANON)))))
817 			revents |= events & (POLLOUT | POLLWRNORM);
818 
819 	if (events & POLLHUP)
820 		if (!ISSET(tp->t_state, TS_CARR_ON))
821 			revents |= POLLHUP;
822 
823 	if (revents == 0) {
824 		if (events & (POLLIN | POLLHUP | POLLRDNORM))
825 			selrecord(l, &pti->pt_selr);
826 
827 		if (events & (POLLOUT | POLLWRNORM))
828 			selrecord(l, &pti->pt_selw);
829 	}
830 
831 	mutex_spin_exit(&tty_lock);
832 
833 	return (revents);
834 }
835 
836 static void
837 filt_ptcrdetach(struct knote *kn)
838 {
839 	struct pt_softc *pti;
840 	struct tty	*tp;
841 
842 	pti = kn->kn_hook;
843 	tp = pti->pt_tty;
844 
845 	mutex_spin_enter(&tty_lock);
846 	SLIST_REMOVE(&pti->pt_selr.sel_klist, kn, knote, kn_selnext);
847 	mutex_spin_exit(&tty_lock);
848 }
849 
850 static int
851 filt_ptcread(struct knote *kn, long hint)
852 {
853 	struct pt_softc *pti;
854 	struct tty	*tp;
855 	int canread;
856 
857 	pti = kn->kn_hook;
858 	tp = pti->pt_tty;
859 
860 	mutex_spin_enter(&tty_lock);
861 
862 	canread = (ISSET(tp->t_state, TS_ISOPEN) &&
863 		    ((tp->t_outq.c_cc > 0 && !ISSET(tp->t_state, TS_TTSTOP)) ||
864 		     ((pti->pt_flags & PF_PKT) && pti->pt_send) ||
865 		     ((pti->pt_flags & PF_UCNTL) && pti->pt_ucntl)));
866 
867 	if (canread) {
868 		/*
869 		 * c_cc is number of characters after output post-processing;
870 		 * the amount of data actually read(2) depends on
871 		 * setting of input flags for the terminal.
872 		 */
873 		kn->kn_data = tp->t_outq.c_cc;
874 		if (((pti->pt_flags & PF_PKT) && pti->pt_send) ||
875 		    ((pti->pt_flags & PF_UCNTL) && pti->pt_ucntl))
876 			kn->kn_data++;
877 	}
878 
879 	mutex_spin_exit(&tty_lock);
880 
881 	return (canread);
882 }
883 
884 static void
885 filt_ptcwdetach(struct knote *kn)
886 {
887 	struct pt_softc *pti;
888 	struct tty	*tp;
889 
890 	pti = kn->kn_hook;
891 	tp = pti->pt_tty;
892 
893 	mutex_spin_enter(&tty_lock);
894 	SLIST_REMOVE(&pti->pt_selw.sel_klist, kn, knote, kn_selnext);
895 	mutex_spin_exit(&tty_lock);
896 }
897 
898 static int
899 filt_ptcwrite(struct knote *kn, long hint)
900 {
901 	struct pt_softc *pti;
902 	struct tty	*tp;
903 	int canwrite;
904 	int nwrite;
905 
906 	pti = kn->kn_hook;
907 	tp = pti->pt_tty;
908 
909 	mutex_spin_enter(&tty_lock);
910 
911 	canwrite = (ISSET(tp->t_state, TS_ISOPEN) &&
912 		    ((pti->pt_flags & PF_REMOTE) ?
913 		     (tp->t_canq.c_cc == 0) :
914 		     ((tp->t_rawq.c_cc + tp->t_canq.c_cc < TTYHOG-2) ||
915 		      (tp->t_canq.c_cc == 0 && ISSET(tp->t_lflag, ICANON)))));
916 
917 	if (canwrite) {
918 		if (pti->pt_flags & PF_REMOTE)
919 			nwrite = tp->t_canq.c_cn;
920 		else {
921 			/* this is guaranteed to be > 0 due to above check */
922 			nwrite = tp->t_canq.c_cn
923 				- (tp->t_rawq.c_cc + tp->t_canq.c_cc);
924 		}
925 		kn->kn_data = nwrite;
926 	}
927 
928 	mutex_spin_exit(&tty_lock);
929 
930 	return (canwrite);
931 }
932 
933 static const struct filterops ptcread_filtops =
934 	{ 1, NULL, filt_ptcrdetach, filt_ptcread };
935 static const struct filterops ptcwrite_filtops =
936 	{ 1, NULL, filt_ptcwdetach, filt_ptcwrite };
937 
938 int
939 ptckqfilter(dev_t dev, struct knote *kn)
940 {
941 	struct pt_softc *pti = pt_softc[minor(dev)];
942 	struct klist	*klist;
943 
944 	switch (kn->kn_filter) {
945 	case EVFILT_READ:
946 		klist = &pti->pt_selr.sel_klist;
947 		kn->kn_fop = &ptcread_filtops;
948 		break;
949 	case EVFILT_WRITE:
950 		klist = &pti->pt_selw.sel_klist;
951 		kn->kn_fop = &ptcwrite_filtops;
952 		break;
953 	default:
954 		return (EINVAL);
955 	}
956 
957 	kn->kn_hook = pti;
958 
959 	mutex_spin_enter(&tty_lock);
960 	SLIST_INSERT_HEAD(klist, kn, kn_selnext);
961 	mutex_spin_exit(&tty_lock);
962 
963 	return (0);
964 }
965 
966 struct tty *
967 ptytty(dev)
968 	dev_t dev;
969 {
970 	struct pt_softc *pti = pt_softc[minor(dev)];
971 	struct tty *tp = pti->pt_tty;
972 
973 	return (tp);
974 }
975 
976 /*ARGSUSED*/
977 int
978 ptyioctl(dev, cmd, data, flag, l)
979 	dev_t dev;
980 	u_long cmd;
981 	void *data;
982 	int flag;
983 	struct lwp *l;
984 {
985 	struct pt_softc *pti = pt_softc[minor(dev)];
986 	struct tty *tp = pti->pt_tty;
987 	const struct cdevsw *cdev;
988 	u_char *cc = tp->t_cc;
989 	int stop, error, sig;
990 
991 	/*
992 	 * IF CONTROLLER STTY THEN MUST FLUSH TO PREVENT A HANG.
993 	 * ttywflush(tp) will hang if there are characters in the outq.
994 	 */
995 	if (cmd == TIOCEXT) {
996 		/*
997 		 * When the EXTPROC bit is being toggled, we need
998 		 * to send an TIOCPKT_IOCTL if the packet driver
999 		 * is turned on.
1000 		 */
1001 		if (*(int *)data) {
1002 			if (pti->pt_flags & PF_PKT) {
1003 				pti->pt_send |= TIOCPKT_IOCTL;
1004 				ptcwakeup(tp, FREAD);
1005 			}
1006 			SET(tp->t_lflag, EXTPROC);
1007 		} else {
1008 			if (ISSET(tp->t_lflag, EXTPROC) &&
1009 			    (pti->pt_flags & PF_PKT)) {
1010 				pti->pt_send |= TIOCPKT_IOCTL;
1011 				ptcwakeup(tp, FREAD);
1012 			}
1013 			CLR(tp->t_lflag, EXTPROC);
1014 		}
1015 		return(0);
1016 	}
1017 
1018 #ifndef NO_DEV_PTM
1019 	/* Allow getting the name from either the master or the slave */
1020 	if (cmd == TIOCPTSNAME)
1021 		return pty_fill_ptmget(l, dev, -1, -1, data);
1022 #endif
1023 
1024 	cdev = cdevsw_lookup(dev);
1025 	if (cdev != NULL && cdev->d_open == ptcopen)
1026 		switch (cmd) {
1027 #ifndef NO_DEV_PTM
1028 		case TIOCGRANTPT:
1029 			return pty_grant_slave(l, dev);
1030 #endif
1031 
1032 		case TIOCGPGRP:
1033 			/*
1034 			 * We avoid calling ttioctl on the controller since,
1035 			 * in that case, tp must be the controlling terminal.
1036 			 */
1037 			*(int *)data = tp->t_pgrp ? tp->t_pgrp->pg_id : 0;
1038 			return (0);
1039 
1040 		case TIOCPKT:
1041 			if (*(int *)data) {
1042 				if (pti->pt_flags & PF_UCNTL)
1043 					return (EINVAL);
1044 				pti->pt_flags |= PF_PKT;
1045 			} else
1046 				pti->pt_flags &= ~PF_PKT;
1047 			return (0);
1048 
1049 		case TIOCUCNTL:
1050 			if (*(int *)data) {
1051 				if (pti->pt_flags & PF_PKT)
1052 					return (EINVAL);
1053 				pti->pt_flags |= PF_UCNTL;
1054 			} else
1055 				pti->pt_flags &= ~PF_UCNTL;
1056 			return (0);
1057 
1058 		case TIOCREMOTE:
1059 			if (*(int *)data)
1060 				pti->pt_flags |= PF_REMOTE;
1061 			else
1062 				pti->pt_flags &= ~PF_REMOTE;
1063 			mutex_spin_enter(&tty_lock);
1064 			ttyflush(tp, FREAD|FWRITE);
1065 			mutex_spin_exit(&tty_lock);
1066 			return (0);
1067 
1068 #ifdef COMPAT_OLDTTY
1069 		case TIOCSETP:
1070 		case TIOCSETN:
1071 #endif
1072 		case TIOCSETD:
1073 		case TIOCSETA:
1074 		case TIOCSETAW:
1075 		case TIOCSETAF:
1076 			mutex_spin_enter(&tty_lock);
1077 			ndflush(&tp->t_outq, tp->t_outq.c_cc);
1078 			mutex_spin_exit(&tty_lock);
1079 			break;
1080 
1081 		case TIOCSIG:
1082 			sig = (int)(long)*(void **)data;
1083 			if (sig <= 0 || sig >= NSIG)
1084 				return (EINVAL);
1085 			mutex_spin_enter(&tty_lock);
1086 			if (!ISSET(tp->t_lflag, NOFLSH))
1087 				ttyflush(tp, FREAD|FWRITE);
1088 			if ((sig == SIGINFO) &&
1089 			    (!ISSET(tp->t_lflag, NOKERNINFO)))
1090 				ttyinfo(tp, 1);
1091 			ttysig(tp, TTYSIG_PG1, sig);
1092 			mutex_spin_exit(&tty_lock);
1093 			return(0);
1094 		}
1095 
1096 	error = (*tp->t_linesw->l_ioctl)(tp, cmd, data, flag, l);
1097 	if (error == EPASSTHROUGH)
1098 		 error = ttioctl(tp, cmd, data, flag, l);
1099 	if (error == EPASSTHROUGH) {
1100 		if (pti->pt_flags & PF_UCNTL &&
1101 		    (cmd & ~0xff) == UIOCCMD(0)) {
1102 			if (cmd & 0xff) {
1103 				pti->pt_ucntl = (u_char)cmd;
1104 				ptcwakeup(tp, FREAD);
1105 			}
1106 			return (0);
1107 		}
1108 	}
1109 	/*
1110 	 * If external processing and packet mode send ioctl packet.
1111 	 */
1112 	if (ISSET(tp->t_lflag, EXTPROC) && (pti->pt_flags & PF_PKT)) {
1113 		switch(cmd) {
1114 		case TIOCSETA:
1115 		case TIOCSETAW:
1116 		case TIOCSETAF:
1117 #ifdef COMPAT_OLDTTY
1118 		case TIOCSETP:
1119 		case TIOCSETN:
1120 		case TIOCSETC:
1121 		case TIOCSLTC:
1122 		case TIOCLBIS:
1123 		case TIOCLBIC:
1124 		case TIOCLSET:
1125 #endif
1126 			pti->pt_send |= TIOCPKT_IOCTL;
1127 			ptcwakeup(tp, FREAD);
1128 		default:
1129 			break;
1130 		}
1131 	}
1132 	stop = ISSET(tp->t_iflag, IXON) && CCEQ(cc[VSTOP], CTRL('s'))
1133 		&& CCEQ(cc[VSTART], CTRL('q'));
1134 	if (pti->pt_flags & PF_NOSTOP) {
1135 		if (stop) {
1136 			pti->pt_send &= ~TIOCPKT_NOSTOP;
1137 			pti->pt_send |= TIOCPKT_DOSTOP;
1138 			pti->pt_flags &= ~PF_NOSTOP;
1139 			ptcwakeup(tp, FREAD);
1140 		}
1141 	} else {
1142 		if (!stop) {
1143 			pti->pt_send &= ~TIOCPKT_DOSTOP;
1144 			pti->pt_send |= TIOCPKT_NOSTOP;
1145 			pti->pt_flags |= PF_NOSTOP;
1146 			ptcwakeup(tp, FREAD);
1147 		}
1148 	}
1149 	return (error);
1150 }
1151