pty.c revision 130585
1/*
2 * Copyright (c) 1982, 1986, 1989, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 4. Neither the name of the University nor the names of its contributors
14 *    may be used to endorse or promote products derived from this software
15 *    without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 *	@(#)tty_pty.c	8.4 (Berkeley) 2/20/95
30 */
31
32#include <sys/cdefs.h>
33__FBSDID("$FreeBSD: head/sys/kern/tty_pty.c 130585 2004-06-16 09:47:26Z phk $");
34
35/*
36 * Pseudo-teletype Driver
37 * (Actually two drivers, requiring two entries in 'cdevsw')
38 */
39#include "opt_compat.h"
40#include "opt_tty.h"
41#include <sys/param.h>
42#include <sys/systm.h>
43#include <sys/lock.h>
44#include <sys/mutex.h>
45#include <sys/sx.h>
46#if defined(COMPAT_43)
47#include <sys/ioctl_compat.h>
48#endif
49#include <sys/proc.h>
50#include <sys/tty.h>
51#include <sys/conf.h>
52#include <sys/fcntl.h>
53#include <sys/poll.h>
54#include <sys/kernel.h>
55#include <sys/vnode.h>
56#include <sys/signalvar.h>
57#include <sys/malloc.h>
58
59static MALLOC_DEFINE(M_PTY, "ptys", "pty data structures");
60
61static void ptsstart(struct tty *tp);
62static void ptsstop(struct tty *tp, int rw);
63static void ptcwakeup(struct tty *tp, int flag);
64static struct cdev *ptyinit(struct cdev *cdev);
65
66static	d_open_t	ptsopen;
67static	d_close_t	ptsclose;
68static	d_read_t	ptsread;
69static	d_write_t	ptswrite;
70static	d_ioctl_t	ptyioctl;
71static	d_open_t	ptcopen;
72static	d_close_t	ptcclose;
73static	d_read_t	ptcread;
74static	d_write_t	ptcwrite;
75static	d_poll_t	ptcpoll;
76
77#define	CDEV_MAJOR_S	5
78static struct cdevsw pts_cdevsw = {
79	.d_version =	D_VERSION,
80	.d_open =	ptsopen,
81	.d_close =	ptsclose,
82	.d_read =	ptsread,
83	.d_write =	ptswrite,
84	.d_ioctl =	ptyioctl,
85	.d_name =	"pts",
86	.d_maj =	CDEV_MAJOR_S,
87	.d_flags =	D_TTY | D_NEEDGIANT,
88};
89
90#define	CDEV_MAJOR_C	6
91static struct cdevsw ptc_cdevsw = {
92	.d_version =	D_VERSION,
93	.d_open =	ptcopen,
94	.d_close =	ptcclose,
95	.d_read =	ptcread,
96	.d_write =	ptcwrite,
97	.d_ioctl =	ptyioctl,
98	.d_poll =	ptcpoll,
99	.d_name =	"ptc",
100	.d_maj =	CDEV_MAJOR_C,
101	.d_flags =	D_TTY | D_NEEDGIANT,
102};
103
104#define BUFSIZ 100		/* Chunk size iomoved to/from user */
105
106struct	ptsc {
107	int	pt_flags;
108	struct	selinfo pt_selr, pt_selw;
109	u_char	pt_send;
110	u_char	pt_ucntl;
111	struct tty *pt_tty;
112	struct cdev *devs, *devc;
113	struct	prison *pt_prison;
114};
115
116#define	PF_PKT		0x08		/* packet mode */
117#define	PF_STOPPED	0x10		/* user told stopped */
118#define	PF_REMOTE	0x20		/* remote and flow controlled input */
119#define	PF_NOSTOP	0x40
120#define PF_UCNTL	0x80		/* user control mode */
121
122#define	TSA_PTC_READ(tp)	((void *)&(tp)->t_outq.c_cf)
123#define	TSA_PTC_WRITE(tp)	((void *)&(tp)->t_rawq.c_cl)
124#define	TSA_PTS_READ(tp)	((void *)&(tp)->t_canq)
125
126static char *names = "pqrsPQRS";
127/*
128 * This function creates and initializes a pts/ptc pair
129 *
130 * pts == /dev/tty[pqrsPQRS][0123456789abcdefghijklmnopqrstuv]
131 * ptc == /dev/pty[pqrsPQRS][0123456789abcdefghijklmnopqrstuv]
132 *
133 * XXX: define and add mapping of upper minor bits to allow more
134 *      than 256 ptys.
135 */
136static struct cdev *
137ptyinit(struct cdev *devc)
138{
139	struct cdev *devs;
140	struct ptsc *pt;
141	int n;
142
143	n = minor(devc);
144	/* For now we only map the lower 8 bits of the minor */
145	if (n & ~0xff)
146		return (NODEV);
147
148	devc->si_flags &= ~SI_CHEAPCLONE;
149
150	pt = malloc(sizeof(*pt), M_PTY, M_WAITOK | M_ZERO);
151	pt->devs = devs = make_dev(&pts_cdevsw, n,
152	    UID_ROOT, GID_WHEEL, 0666, "tty%c%r", names[n / 32], n % 32);
153	pt->devc = devc;
154
155	pt->pt_tty = ttymalloc(pt->pt_tty);
156	devs->si_drv1 = devc->si_drv1 = pt;
157	devs->si_tty = devc->si_tty = pt->pt_tty;
158	pt->pt_tty->t_dev = devs;
159	return (devc);
160}
161
162/*ARGSUSED*/
163static	int
164ptsopen(struct cdev *dev, int flag, int devtype, struct thread *td)
165{
166	struct tty *tp;
167	int error;
168	struct ptsc *pt;
169
170	if (!dev->si_drv1)
171		return(ENXIO);
172	pt = dev->si_drv1;
173	tp = dev->si_tty;
174	if ((tp->t_state & TS_ISOPEN) == 0) {
175		ttychars(tp);		/* Set up default chars */
176		tp->t_iflag = TTYDEF_IFLAG;
177		tp->t_oflag = TTYDEF_OFLAG;
178		tp->t_lflag = TTYDEF_LFLAG;
179		tp->t_cflag = TTYDEF_CFLAG;
180		tp->t_ispeed = tp->t_ospeed = TTYDEF_SPEED;
181	} else if (tp->t_state & TS_XCLUDE && suser(td))
182		return (EBUSY);
183	else if (pt->pt_prison != td->td_ucred->cr_prison)
184		return (EBUSY);
185	if (tp->t_oproc)			/* Ctrlr still around. */
186		(void)ttyld_modem(tp, 1);
187	while ((tp->t_state & TS_CARR_ON) == 0) {
188		if (flag&FNONBLOCK)
189			break;
190		error = ttysleep(tp, TSA_CARR_ON(tp), TTIPRI | PCATCH,
191				 "ptsopn", 0);
192		if (error)
193			return (error);
194	}
195	error = ttyld_open(tp, dev);
196	if (error == 0)
197		ptcwakeup(tp, FREAD|FWRITE);
198	return (error);
199}
200
201static	int
202ptsclose(struct cdev *dev, int flag, int mode, struct thread *td)
203{
204	struct tty *tp;
205	int err;
206
207	tp = dev->si_tty;
208	err = ttyld_close(tp, flag);
209	(void) ttyclose(tp);
210	return (err);
211}
212
213static	int
214ptsread(struct cdev *dev, struct uio *uio, int flag)
215{
216	struct thread *td = curthread;
217	struct proc *p = td->td_proc;
218	struct tty *tp = dev->si_tty;
219	struct ptsc *pt = dev->si_drv1;
220	struct pgrp *pg;
221	int error = 0;
222
223again:
224	if (pt->pt_flags & PF_REMOTE) {
225		while (isbackground(p, tp)) {
226			sx_slock(&proctree_lock);
227			PROC_LOCK(p);
228			if (SIGISMEMBER(p->p_sigacts->ps_sigignore, SIGTTIN) ||
229			    SIGISMEMBER(td->td_sigmask, SIGTTIN) ||
230			    p->p_pgrp->pg_jobc == 0 || p->p_flag & P_PPWAIT) {
231				PROC_UNLOCK(p);
232				sx_sunlock(&proctree_lock);
233				return (EIO);
234			}
235			pg = p->p_pgrp;
236			PROC_UNLOCK(p);
237			PGRP_LOCK(pg);
238			sx_sunlock(&proctree_lock);
239			pgsignal(pg, SIGTTIN, 1);
240			PGRP_UNLOCK(pg);
241			error = ttysleep(tp, &lbolt, TTIPRI | PCATCH, "ptsbg",
242					 0);
243			if (error)
244				return (error);
245		}
246		if (tp->t_canq.c_cc == 0) {
247			if (flag & IO_NDELAY)
248				return (EWOULDBLOCK);
249			error = ttysleep(tp, TSA_PTS_READ(tp), TTIPRI | PCATCH,
250					 "ptsin", 0);
251			if (error)
252				return (error);
253			goto again;
254		}
255		while (tp->t_canq.c_cc > 1 && uio->uio_resid > 0)
256			if (ureadc(getc(&tp->t_canq), uio) < 0) {
257				error = EFAULT;
258				break;
259			}
260		if (tp->t_canq.c_cc == 1)
261			(void) getc(&tp->t_canq);
262		if (tp->t_canq.c_cc)
263			return (error);
264	} else
265		if (tp->t_oproc)
266			error = ttyld_read(tp, uio, flag);
267	ptcwakeup(tp, FWRITE);
268	return (error);
269}
270
271/*
272 * Write to pseudo-tty.
273 * Wakeups of controlling tty will happen
274 * indirectly, when tty driver calls ptsstart.
275 */
276static	int
277ptswrite(struct cdev *dev, struct uio *uio, int flag)
278{
279	struct tty *tp;
280
281	tp = dev->si_tty;
282	if (tp->t_oproc == 0)
283		return (EIO);
284	return (ttyld_write(tp, uio, flag));
285}
286
287/*
288 * Start output on pseudo-tty.
289 * Wake up process selecting or sleeping for input from controlling tty.
290 */
291static void
292ptsstart(struct tty *tp)
293{
294	struct ptsc *pt = tp->t_dev->si_drv1;
295
296	if (tp->t_state & TS_TTSTOP)
297		return;
298	if (pt->pt_flags & PF_STOPPED) {
299		pt->pt_flags &= ~PF_STOPPED;
300		pt->pt_send = TIOCPKT_START;
301	}
302	ptcwakeup(tp, FREAD);
303}
304
305static void
306ptcwakeup(struct tty *tp, int flag)
307{
308	struct ptsc *pt = tp->t_dev->si_drv1;
309
310	if (flag & FREAD) {
311		selwakeuppri(&pt->pt_selr, TTIPRI);
312		wakeup(TSA_PTC_READ(tp));
313	}
314	if (flag & FWRITE) {
315		selwakeuppri(&pt->pt_selw, TTOPRI);
316		wakeup(TSA_PTC_WRITE(tp));
317	}
318}
319
320static	int
321ptcopen(struct cdev *dev, int flag, int devtype, struct thread *td)
322{
323	struct tty *tp;
324	struct ptsc *pt;
325
326	if (!dev->si_drv1)
327		ptyinit(dev);
328	if (!dev->si_drv1)
329		return(ENXIO);
330	tp = dev->si_tty;
331	if (tp->t_oproc)
332		return (EIO);
333	tp->t_timeout = -1;
334	tp->t_oproc = ptsstart;
335	tp->t_stop = ptsstop;
336	(void)ttyld_modem(tp, 1);
337	tp->t_lflag &= ~EXTPROC;
338	pt = dev->si_drv1;
339	pt->pt_prison = td->td_ucred->cr_prison;
340	pt->pt_flags = 0;
341	pt->pt_send = 0;
342	pt->pt_ucntl = 0;
343	return (0);
344}
345
346static	int
347ptcclose(struct cdev *dev, int flags, int fmt, struct thread *td)
348{
349	struct tty *tp;
350
351	tp = dev->si_tty;
352	(void)ttyld_modem(tp, 0);
353
354	/*
355	 * XXX MDMBUF makes no sense for ptys but would inhibit the above
356	 * l_modem().  CLOCAL makes sense but isn't supported.   Special
357	 * l_modem()s that ignore carrier drop make no sense for ptys but
358	 * may be in use because other parts of the line discipline make
359	 * sense for ptys.  Recover by doing everything that a normal
360	 * ttymodem() would have done except for sending a SIGHUP.
361	 */
362	if (tp->t_state & TS_ISOPEN) {
363		tp->t_state &= ~(TS_CARR_ON | TS_CONNECTED);
364		tp->t_state |= TS_ZOMBIE;
365		ttyflush(tp, FREAD | FWRITE);
366	}
367
368	tp->t_oproc = 0;		/* mark closed */
369	return (0);
370}
371
372static	int
373ptcread(struct cdev *dev, struct uio *uio, int flag)
374{
375	struct tty *tp = dev->si_tty;
376	struct ptsc *pt = dev->si_drv1;
377	char buf[BUFSIZ];
378	int error = 0, cc;
379
380	/*
381	 * We want to block until the slave
382	 * is open, and there's something to read;
383	 * but if we lost the slave or we're NBIO,
384	 * then return the appropriate error instead.
385	 */
386	for (;;) {
387		if (tp->t_state&TS_ISOPEN) {
388			if (pt->pt_flags&PF_PKT && pt->pt_send) {
389				error = ureadc((int)pt->pt_send, uio);
390				if (error)
391					return (error);
392				if (pt->pt_send & TIOCPKT_IOCTL) {
393					cc = min(uio->uio_resid,
394						sizeof(tp->t_termios));
395					uiomove(&tp->t_termios, cc, uio);
396				}
397				pt->pt_send = 0;
398				return (0);
399			}
400			if (pt->pt_flags&PF_UCNTL && pt->pt_ucntl) {
401				error = ureadc((int)pt->pt_ucntl, uio);
402				if (error)
403					return (error);
404				pt->pt_ucntl = 0;
405				return (0);
406			}
407			if (tp->t_outq.c_cc && (tp->t_state&TS_TTSTOP) == 0)
408				break;
409		}
410		if ((tp->t_state & TS_CONNECTED) == 0)
411			return (0);	/* EOF */
412		if (flag & IO_NDELAY)
413			return (EWOULDBLOCK);
414		error = tsleep(TSA_PTC_READ(tp), TTIPRI | PCATCH, "ptcin", 0);
415		if (error)
416			return (error);
417	}
418	if (pt->pt_flags & (PF_PKT|PF_UCNTL))
419		error = ureadc(0, uio);
420	while (uio->uio_resid > 0 && error == 0) {
421		cc = q_to_b(&tp->t_outq, buf, min(uio->uio_resid, BUFSIZ));
422		if (cc <= 0)
423			break;
424		error = uiomove(buf, cc, uio);
425	}
426	ttwwakeup(tp);
427	return (error);
428}
429
430static	void
431ptsstop(struct tty *tp, int flush)
432{
433	struct ptsc *pt = tp->t_dev->si_drv1;
434	int flag;
435
436	/* note: FLUSHREAD and FLUSHWRITE already ok */
437	if (flush == 0) {
438		flush = TIOCPKT_STOP;
439		pt->pt_flags |= PF_STOPPED;
440	} else
441		pt->pt_flags &= ~PF_STOPPED;
442	pt->pt_send |= flush;
443	/* change of perspective */
444	flag = 0;
445	if (flush & FREAD)
446		flag |= FWRITE;
447	if (flush & FWRITE)
448		flag |= FREAD;
449	ptcwakeup(tp, flag);
450}
451
452static	int
453ptcpoll(struct cdev *dev, int events, struct thread *td)
454{
455	struct tty *tp = dev->si_tty;
456	struct ptsc *pt = dev->si_drv1;
457	int revents = 0;
458	int s;
459
460	if ((tp->t_state & TS_CONNECTED) == 0)
461		return (events &
462		   (POLLHUP | POLLIN | POLLRDNORM | POLLOUT | POLLWRNORM));
463
464	/*
465	 * Need to block timeouts (ttrstart).
466	 */
467	s = spltty();
468
469	if (events & (POLLIN | POLLRDNORM))
470		if ((tp->t_state & TS_ISOPEN) &&
471		    ((tp->t_outq.c_cc && (tp->t_state & TS_TTSTOP) == 0) ||
472		     ((pt->pt_flags & PF_PKT) && pt->pt_send) ||
473		     ((pt->pt_flags & PF_UCNTL) && pt->pt_ucntl)))
474			revents |= events & (POLLIN | POLLRDNORM);
475
476	if (events & (POLLOUT | POLLWRNORM))
477		if (tp->t_state & TS_ISOPEN &&
478		    ((pt->pt_flags & PF_REMOTE) ?
479		     (tp->t_canq.c_cc == 0) :
480		     ((tp->t_rawq.c_cc + tp->t_canq.c_cc < TTYHOG - 2) ||
481		      (tp->t_canq.c_cc == 0 && (tp->t_lflag & ICANON)))))
482			revents |= events & (POLLOUT | POLLWRNORM);
483
484	if (events & POLLHUP)
485		if ((tp->t_state & TS_CARR_ON) == 0)
486			revents |= POLLHUP;
487
488	if (revents == 0) {
489		if (events & (POLLIN | POLLRDNORM))
490			selrecord(td, &pt->pt_selr);
491
492		if (events & (POLLOUT | POLLWRNORM))
493			selrecord(td, &pt->pt_selw);
494	}
495	splx(s);
496
497	return (revents);
498}
499
500static	int
501ptcwrite(struct cdev *dev, struct uio *uio, int flag)
502{
503	struct tty *tp = dev->si_tty;
504	u_char *cp = 0;
505	int cc = 0;
506	u_char locbuf[BUFSIZ];
507	int cnt = 0;
508	struct ptsc *pt = dev->si_drv1;
509	int error = 0;
510
511again:
512	if ((tp->t_state&TS_ISOPEN) == 0)
513		goto block;
514	if (pt->pt_flags & PF_REMOTE) {
515		if (tp->t_canq.c_cc)
516			goto block;
517		while ((uio->uio_resid > 0 || cc > 0) &&
518		       tp->t_canq.c_cc < TTYHOG - 1) {
519			if (cc == 0) {
520				cc = min(uio->uio_resid, BUFSIZ);
521				cc = min(cc, TTYHOG - 1 - tp->t_canq.c_cc);
522				cp = locbuf;
523				error = uiomove(cp, cc, uio);
524				if (error)
525					return (error);
526				/* check again for safety */
527				if ((tp->t_state & TS_ISOPEN) == 0) {
528					/* adjust as usual */
529					uio->uio_resid += cc;
530					return (EIO);
531				}
532			}
533			if (cc > 0) {
534				cc = b_to_q((char *)cp, cc, &tp->t_canq);
535				/*
536				 * XXX we don't guarantee that the canq size
537				 * is >= TTYHOG, so the above b_to_q() may
538				 * leave some bytes uncopied.  However, space
539				 * is guaranteed for the null terminator if
540				 * we don't fail here since (TTYHOG - 1) is
541				 * not a multiple of CBSIZE.
542				 */
543				if (cc > 0)
544					break;
545			}
546		}
547		/* adjust for data copied in but not written */
548		uio->uio_resid += cc;
549		(void) putc(0, &tp->t_canq);
550		ttwakeup(tp);
551		wakeup(TSA_PTS_READ(tp));
552		return (0);
553	}
554	while (uio->uio_resid > 0 || cc > 0) {
555		if (cc == 0) {
556			cc = min(uio->uio_resid, BUFSIZ);
557			cp = locbuf;
558			error = uiomove(cp, cc, uio);
559			if (error)
560				return (error);
561			/* check again for safety */
562			if ((tp->t_state & TS_ISOPEN) == 0) {
563				/* adjust for data copied in but not written */
564				uio->uio_resid += cc;
565				return (EIO);
566			}
567		}
568		while (cc > 0) {
569			if ((tp->t_rawq.c_cc + tp->t_canq.c_cc) >= TTYHOG - 2 &&
570			   (tp->t_canq.c_cc > 0 || !(tp->t_lflag&ICANON))) {
571				wakeup(TSA_HUP_OR_INPUT(tp));
572				goto block;
573			}
574			ttyld_rint(tp, *cp++);
575			cnt++;
576			cc--;
577		}
578		cc = 0;
579	}
580	return (0);
581block:
582	/*
583	 * Come here to wait for slave to open, for space
584	 * in outq, or space in rawq, or an empty canq.
585	 */
586	if ((tp->t_state & TS_CONNECTED) == 0) {
587		/* adjust for data copied in but not written */
588		uio->uio_resid += cc;
589		return (EIO);
590	}
591	if (flag & IO_NDELAY) {
592		/* adjust for data copied in but not written */
593		uio->uio_resid += cc;
594		if (cnt == 0)
595			return (EWOULDBLOCK);
596		return (0);
597	}
598	error = tsleep(TSA_PTC_WRITE(tp), TTOPRI | PCATCH, "ptcout", 0);
599	if (error) {
600		/* adjust for data copied in but not written */
601		uio->uio_resid += cc;
602		return (error);
603	}
604	goto again;
605}
606
607/*ARGSUSED*/
608static	int
609ptyioctl(struct cdev *dev, u_long cmd, caddr_t data, int flag, struct thread *td)
610{
611	struct tty *tp = dev->si_tty;
612	struct ptsc *pt = dev->si_drv1;
613	u_char *cc = tp->t_cc;
614	int stop, error;
615
616	if (devsw(dev)->d_open == ptcopen) {
617		switch (cmd) {
618
619		case TIOCGPGRP:
620			/*
621			 * We avoid calling ttioctl on the controller since,
622			 * in that case, tp must be the controlling terminal.
623			 */
624			*(int *)data = tp->t_pgrp ? tp->t_pgrp->pg_id : 0;
625			return (0);
626
627		case TIOCPKT:
628			if (*(int *)data) {
629				if (pt->pt_flags & PF_UCNTL)
630					return (EINVAL);
631				pt->pt_flags |= PF_PKT;
632			} else
633				pt->pt_flags &= ~PF_PKT;
634			return (0);
635
636		case TIOCUCNTL:
637			if (*(int *)data) {
638				if (pt->pt_flags & PF_PKT)
639					return (EINVAL);
640				pt->pt_flags |= PF_UCNTL;
641			} else
642				pt->pt_flags &= ~PF_UCNTL;
643			return (0);
644
645		case TIOCREMOTE:
646			if (*(int *)data)
647				pt->pt_flags |= PF_REMOTE;
648			else
649				pt->pt_flags &= ~PF_REMOTE;
650			ttyflush(tp, FREAD|FWRITE);
651			return (0);
652		}
653
654		/*
655		 * The rest of the ioctls shouldn't be called until
656		 * the slave is open.
657		 */
658		if ((tp->t_state & TS_ISOPEN) == 0)
659			return (EAGAIN);
660
661		switch (cmd) {
662#ifdef COMPAT_43
663		case TIOCSETP:
664		case TIOCSETN:
665#endif
666		case TIOCSETD:
667		case TIOCSETA:
668		case TIOCSETAW:
669		case TIOCSETAF:
670			/*
671			 * IF CONTROLLER STTY THEN MUST FLUSH TO PREVENT A HANG.
672			 * ttywflush(tp) will hang if there are characters in
673			 * the outq.
674			 */
675			ndflush(&tp->t_outq, tp->t_outq.c_cc);
676			break;
677
678		case TIOCSIG:
679			if (*(unsigned int *)data >= NSIG ||
680			    *(unsigned int *)data == 0)
681				return(EINVAL);
682			if ((tp->t_lflag&NOFLSH) == 0)
683				ttyflush(tp, FREAD|FWRITE);
684			if (tp->t_pgrp != NULL) {
685				PGRP_LOCK(tp->t_pgrp);
686				pgsignal(tp->t_pgrp, *(unsigned int *)data, 1);
687				PGRP_UNLOCK(tp->t_pgrp);
688			}
689			if ((*(unsigned int *)data == SIGINFO) &&
690			    ((tp->t_lflag&NOKERNINFO) == 0))
691				ttyinfo(tp);
692			return(0);
693		}
694	}
695	if (cmd == TIOCEXT) {
696		/*
697		 * When the EXTPROC bit is being toggled, we need
698		 * to send an TIOCPKT_IOCTL if the packet driver
699		 * is turned on.
700		 */
701		if (*(int *)data) {
702			if (pt->pt_flags & PF_PKT) {
703				pt->pt_send |= TIOCPKT_IOCTL;
704				ptcwakeup(tp, FREAD);
705			}
706			tp->t_lflag |= EXTPROC;
707		} else {
708			if ((tp->t_lflag & EXTPROC) &&
709			    (pt->pt_flags & PF_PKT)) {
710				pt->pt_send |= TIOCPKT_IOCTL;
711				ptcwakeup(tp, FREAD);
712			}
713			tp->t_lflag &= ~EXTPROC;
714		}
715		return(0);
716	}
717	error = ttyioctl(dev, cmd, data, flag, td);
718	if (error == ENOTTY) {
719		if (pt->pt_flags & PF_UCNTL &&
720		    (cmd & ~0xff) == UIOCCMD(0)) {
721			if (cmd & 0xff) {
722				pt->pt_ucntl = (u_char)cmd;
723				ptcwakeup(tp, FREAD);
724			}
725			return (0);
726		}
727		error = ENOTTY;
728	}
729	/*
730	 * If external processing and packet mode send ioctl packet.
731	 */
732	if ((tp->t_lflag&EXTPROC) && (pt->pt_flags & PF_PKT)) {
733		switch(cmd) {
734		case TIOCSETA:
735		case TIOCSETAW:
736		case TIOCSETAF:
737#ifdef COMPAT_43
738		case TIOCSETP:
739		case TIOCSETN:
740#endif
741#if defined(COMPAT_43)
742		case TIOCSETC:
743		case TIOCSLTC:
744		case TIOCLBIS:
745		case TIOCLBIC:
746		case TIOCLSET:
747#endif
748			pt->pt_send |= TIOCPKT_IOCTL;
749			ptcwakeup(tp, FREAD);
750			break;
751		default:
752			break;
753		}
754	}
755	stop = (tp->t_iflag & IXON) && CCEQ(cc[VSTOP], CTRL('s'))
756		&& CCEQ(cc[VSTART], CTRL('q'));
757	if (pt->pt_flags & PF_NOSTOP) {
758		if (stop) {
759			pt->pt_send &= ~TIOCPKT_NOSTOP;
760			pt->pt_send |= TIOCPKT_DOSTOP;
761			pt->pt_flags &= ~PF_NOSTOP;
762			ptcwakeup(tp, FREAD);
763		}
764	} else {
765		if (!stop) {
766			pt->pt_send &= ~TIOCPKT_DOSTOP;
767			pt->pt_send |= TIOCPKT_NOSTOP;
768			pt->pt_flags |= PF_NOSTOP;
769			ptcwakeup(tp, FREAD);
770		}
771	}
772	return (error);
773}
774
775static void
776pty_clone(void *arg, char *name, int namelen, struct cdev **dev)
777{
778	int u;
779
780	if (*dev != NODEV)
781		return;
782	if (bcmp(name, "pty", 3) != 0)
783		return;
784	if (name[5] != '\0')
785		return;
786	switch (name[3]) {
787	case 'p': u =   0; break;
788	case 'q': u =  32; break;
789	case 'r': u =  64; break;
790	case 's': u =  96; break;
791	case 'P': u = 128; break;
792	case 'Q': u = 160; break;
793	case 'R': u = 192; break;
794	case 'S': u = 224; break;
795	default: return;
796	}
797	if (name[4] >= '0' && name[4] <= '9')
798		u += name[4] - '0';
799	else if (name[4] >= 'a' && name[4] <= 'v')
800		u += name[4] - 'a' + 10;
801	else
802		return;
803	*dev = make_dev(&ptc_cdevsw, u,
804	    UID_ROOT, GID_WHEEL, 0666, "pty%c%r", names[u / 32], u % 32);
805	(*dev)->si_flags |= SI_CHEAPCLONE;
806	return;
807}
808
809static void
810ptc_drvinit(void *unused)
811{
812
813	EVENTHANDLER_REGISTER(dev_clone, pty_clone, 0, 1000);
814}
815
816SYSINIT(ptcdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR_C,ptc_drvinit,NULL)
817