nmdm.c revision 81508 
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 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by the University of
16 *	California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 * $FreeBSD: head/sys/dev/nmdm/nmdm.c 81508 2001-08-11 00:18:15Z mp $
34 */
35
36/*
37 * Pseudo-nulmodem Driver
38 */
39#include "opt_compat.h"
40#include <sys/param.h>
41#include <sys/systm.h>
42#if defined(COMPAT_43) || defined(COMPAT_SUNOS)
43#include <sys/ioctl_compat.h>
44#endif
45#include <sys/proc.h>
46#include <sys/tty.h>
47#include <sys/conf.h>
48#include <sys/fcntl.h>
49#include <sys/poll.h>
50#include <sys/kernel.h>
51#include <sys/vnode.h>
52#include <sys/signalvar.h>
53#include <sys/malloc.h>
54
55MALLOC_DEFINE(M_NLMDM, "nullmodem", "nullmodem data structures");
56
57static void nmdmstart __P((struct tty *tp));
58static void nmdmstop __P((struct tty *tp, int rw));
59static void wakeup_other __P((struct tty *tp, int flag));
60static void nmdminit __P((int n));
61
62static	d_open_t	nmdmopen;
63static	d_close_t	nmdmclose;
64static	d_read_t	nmdmread;
65static	d_write_t	nmdmwrite;
66static	d_ioctl_t	nmdmioctl;
67
68#define	CDEV_MAJOR	18
69static struct cdevsw nmdm_cdevsw = {
70	/* open */	nmdmopen,
71	/* close */	nmdmclose,
72	/* read */	nmdmread,
73	/* write */	nmdmwrite,
74	/* ioctl */	nmdmioctl,
75	/* poll */	ttypoll,
76	/* mmap */	nommap,
77	/* strategy */	nostrategy,
78	/* name */	"pts",
79	/* maj */	CDEV_MAJOR,
80	/* dump */	nodump,
81	/* psize */	nopsize,
82	/* flags */	D_TTY,
83};
84
85#define BUFSIZ 100		/* Chunk size iomoved to/from user */
86
87struct softpart {
88	struct tty nm_tty;
89	dev_t	dev;
90	int	modemsignals;	/* bits defined in sys/ttycom.h */
91	int	gotbreak;
92};
93
94struct	nm_softc {
95	int	pt_flags;
96	struct softpart part1, part2;
97	struct	prison *pt_prison;
98};
99
100#define	PF_STOPPED	0x10		/* user told stopped */
101
102static void
103nmdm_crossover(struct nm_softc *pti,
104		struct softpart *ourpart,
105		struct softpart *otherpart);
106
107#define GETPARTS(tp, ourpart, otherpart) \
108do {	\
109	struct nm_softc *pti = tp->t_dev->si_drv1; \
110	if (tp == &pti->part1.nm_tty) { \
111		ourpart = &pti->part1; \
112		otherpart = &pti->part2; \
113	} else { \
114		ourpart = &pti->part2; \
115		otherpart = &pti->part1; \
116	}  \
117} while (0)
118
119/*
120 * This function creates and initializes a pair of ttys.
121 */
122static void
123nmdminit(n)
124	int n;
125{
126	dev_t dev1, dev2;
127	struct nm_softc *pt;
128
129	/* For now we only map the lower 8 bits of the minor */
130	if (n & ~0xff)
131		return;
132
133	pt = malloc(sizeof(*pt), M_NLMDM, M_WAITOK);
134	bzero(pt, sizeof(*pt));
135	pt->part1.dev = dev1 = make_dev(&nmdm_cdevsw, n+n,
136	    0, 0, 0666, "nmdm%dA", n);
137	pt->part2.dev = dev2 = make_dev(&nmdm_cdevsw, n+n+1,
138	    0, 0, 0666, "nmdm%dB", n);
139
140	dev1->si_drv1 = dev2->si_drv1 = pt;
141	dev1->si_tty = &pt->part1.nm_tty;
142	dev2->si_tty = &pt->part2.nm_tty;
143	ttyregister(&pt->part1.nm_tty);
144	ttyregister(&pt->part2.nm_tty);
145	pt->part1.nm_tty.t_oproc = nmdmstart;
146	pt->part2.nm_tty.t_oproc = nmdmstart;
147	pt->part1.nm_tty.t_stop = nmdmstop;
148	pt->part2.nm_tty.t_dev = dev1;
149	pt->part1.nm_tty.t_dev = dev2;
150	pt->part2.nm_tty.t_stop = nmdmstop;
151}
152
153/*ARGSUSED*/
154static	int
155nmdmopen(dev, flag, devtype, p)
156	dev_t dev;
157	int flag, devtype;
158	struct proc *p;
159{
160	register struct tty *tp, *tp2;
161	int error;
162	int minr;
163	dev_t nextdev;
164	struct nm_softc *pti;
165	int is_b;
166	int	pair;
167	struct	softpart *ourpart, *otherpart;
168
169	/*
170	 * XXX: Gross hack for DEVFS:
171	 * If we openned this device, ensure we have the
172	 * next one too, so people can open it.
173	 */
174	minr = dev2unit(dev);
175	pair = minr >> 1;
176	is_b = minr & 1;
177
178	if (pair < 127) {
179		nextdev = makedev(major(dev), (pair+pair) + 1);
180		if (!nextdev->si_drv1) {
181			nmdminit(pair + 1);
182		}
183	}
184	if (!dev->si_drv1)
185		nmdminit(pair);
186
187	if (!dev->si_drv1)
188		return(ENXIO);
189
190	pti = dev->si_drv1;
191	if (is_b)
192		tp = &pti->part2.nm_tty;
193	else
194		tp = &pti->part1.nm_tty;
195	GETPARTS(tp, ourpart, otherpart);
196	tp2 = &otherpart->nm_tty;
197	ourpart->modemsignals |= TIOCM_LE;
198
199	if ((tp->t_state & TS_ISOPEN) == 0) {
200		ttychars(tp);		/* Set up default chars */
201		tp->t_iflag = TTYDEF_IFLAG;
202		tp->t_oflag = TTYDEF_OFLAG;
203		tp->t_lflag = TTYDEF_LFLAG;
204		tp->t_cflag = TTYDEF_CFLAG;
205		tp->t_ispeed = tp->t_ospeed = TTYDEF_SPEED;
206	} else if (tp->t_state & TS_XCLUDE && suser(p)) {
207		return (EBUSY);
208	} else if (pti->pt_prison != p->p_ucred->cr_prison) {
209		return (EBUSY);
210	}
211
212	/*
213	 * If the other side is open we have carrier
214	 */
215	if (tp2->t_state & TS_ISOPEN) {
216		(void)(*linesw[tp->t_line].l_modem)(tp, 1);
217	}
218
219	/*
220	 * And the other side gets carrier as we are now open.
221	 */
222	(void)(*linesw[tp2->t_line].l_modem)(tp2, 1);
223
224	/* External processing makes no sense here */
225	tp->t_lflag &= ~EXTPROC;
226
227	/*
228	 * Wait here if we don't have carrier.
229	 */
230#if 0
231	while ((tp->t_state & TS_CARR_ON) == 0) {
232		if (flag & FNONBLOCK)
233			break;
234		error = ttysleep(tp, TSA_CARR_ON(tp), TTIPRI | PCATCH,
235				 "nmdopn", 0);
236		if (error)
237			return (error);
238	}
239#endif
240
241	/*
242	 * Give the line disciplin a chance to set this end up.
243	 */
244	error = (*linesw[tp->t_line].l_open)(dev, tp);
245
246	/*
247	 * Wake up the other side.
248	 * Theoretically not needed.
249	 */
250	ourpart->modemsignals |= TIOCM_DTR;
251	nmdm_crossover(pti, ourpart, otherpart);
252	if (error == 0)
253		wakeup_other(tp, FREAD|FWRITE); /* XXX */
254	return (error);
255}
256
257static	int
258nmdmclose(dev, flag, mode, p)
259	dev_t dev;
260	int flag, mode;
261	struct proc *p;
262{
263	register struct tty *tp, *tp2;
264	int err;
265	struct softpart *ourpart, *otherpart;
266
267	/*
268	 * let the other end know that the game is up
269	 */
270	tp = dev->si_tty;
271	GETPARTS(tp, ourpart, otherpart);
272	tp2 = &otherpart->nm_tty;
273	(void)(*linesw[tp2->t_line].l_modem)(tp2, 0);
274
275	/*
276	 * XXX MDMBUF makes no sense for nmdms but would inhibit the above
277	 * l_modem().  CLOCAL makes sense but isn't supported.   Special
278	 * l_modem()s that ignore carrier drop make no sense for nmdms but
279	 * may be in use because other parts of the line discipline make
280	 * sense for nmdms.  Recover by doing everything that a normal
281	 * ttymodem() would have done except for sending a SIGHUP.
282	 */
283	if (tp2->t_state & TS_ISOPEN) {
284		tp2->t_state &= ~(TS_CARR_ON | TS_CONNECTED);
285		tp2->t_state |= TS_ZOMBIE;
286		ttyflush(tp2, FREAD | FWRITE);
287	}
288
289	err = (*linesw[tp->t_line].l_close)(tp, flag);
290	ourpart->modemsignals &= ~TIOCM_DTR;
291	nmdm_crossover(dev->si_drv1, ourpart, otherpart);
292	nmdmstop(tp, FREAD|FWRITE);
293	(void) ttyclose(tp);
294	return (err);
295}
296
297static	int
298nmdmread(dev, uio, flag)
299	dev_t dev;
300	struct uio *uio;
301	int flag;
302{
303	int error = 0;
304	struct tty *tp, *tp2;
305	struct softpart *ourpart, *otherpart;
306
307	tp = dev->si_tty;
308	GETPARTS(tp, ourpart, otherpart);
309	tp2 = &otherpart->nm_tty;
310
311#if 0
312	if (tp2->t_state & TS_ISOPEN) {
313		error = (*linesw[tp->t_line].l_read)(tp, uio, flag);
314		wakeup_other(tp, FWRITE);
315	} else {
316		if (flag & IO_NDELAY) {
317			return (EWOULDBLOCK);
318		}
319		error = tsleep(TSA_PTC_READ(tp),
320				TTIPRI | PCATCH, "nmdout", 0);
321		}
322	}
323#else
324	if ((error = (*linesw[tp->t_line].l_read)(tp, uio, flag)) == 0)
325		wakeup_other(tp, FWRITE);
326#endif
327	return (error);
328}
329
330/*
331 * Write to pseudo-tty.
332 * Wakeups of controlling tty will happen
333 * indirectly, when tty driver calls nmdmstart.
334 */
335static	int
336nmdmwrite(dev, uio, flag)
337	dev_t dev;
338	struct uio *uio;
339	int flag;
340{
341	register u_char *cp = 0;
342	register int cc = 0;
343	u_char locbuf[BUFSIZ];
344	int cnt = 0;
345	int error = 0;
346	struct tty *tp1, *tp;
347	struct softpart *ourpart, *otherpart;
348
349	tp1 = dev->si_tty;
350	/*
351	 * Get the other tty struct.
352	 * basically we are writing into the INPUT side of the other device.
353	 */
354	GETPARTS(tp1, ourpart, otherpart);
355	tp = &otherpart->nm_tty;
356
357again:
358	if ((tp->t_state & TS_ISOPEN) == 0)
359		return (EIO);
360	while (uio->uio_resid > 0 || cc > 0) {
361		/*
362		 * Fill up the buffer if it's empty
363		 */
364		if (cc == 0) {
365			cc = min(uio->uio_resid, BUFSIZ);
366			cp = locbuf;
367			error = uiomove((caddr_t)cp, cc, uio);
368			if (error)
369				return (error);
370			/* check again for safety */
371			if ((tp->t_state & TS_ISOPEN) == 0) {
372				/* adjust for data copied in but not written */
373				uio->uio_resid += cc;
374				return (EIO);
375			}
376		}
377		while (cc > 0) {
378			if (((tp->t_rawq.c_cc + tp->t_canq.c_cc) >= (TTYHOG-2))
379			&& ((tp->t_canq.c_cc > 0) || !(tp->t_iflag&ICANON))) {
380				/*
381	 			 * Come here to wait for space in outq,
382				 * or space in rawq, or an empty canq.
383	 			 */
384				wakeup(TSA_HUP_OR_INPUT(tp));
385				if ((tp->t_state & TS_CONNECTED) == 0) {
386					/*
387					 * Data piled up because not connected.
388					 * Adjust for data copied in but
389					 * not written.
390					 */
391					uio->uio_resid += cc;
392					return (EIO);
393				}
394				if (flag & IO_NDELAY) {
395					/*
396				         * Don't wait if asked not to.
397					 * Adjust for data copied in but
398					 * not written.
399					 */
400					uio->uio_resid += cc;
401					if (cnt == 0)
402						return (EWOULDBLOCK);
403					return (0);
404				}
405				error = tsleep(TSA_PTC_WRITE(tp),
406						TTOPRI | PCATCH, "nmdout", 0);
407				if (error) {
408					/*
409					 * Tsleep returned (signal?).
410					 * Go find out what the user wants.
411					 * adjust for data copied in but
412					 * not written
413					 */
414					uio->uio_resid += cc;
415					return (error);
416				}
417				goto again;
418			}
419			(*linesw[tp->t_line].l_rint)(*cp++, tp);
420			cnt++;
421			cc--;
422		}
423		cc = 0;
424	}
425	return (0);
426}
427
428/*
429 * Start output on pseudo-tty.
430 * Wake up process selecting or sleeping for input from controlling tty.
431 */
432static void
433nmdmstart(tp)
434	struct tty *tp;
435{
436	register struct nm_softc *pti = tp->t_dev->si_drv1;
437
438	if (tp->t_state & TS_TTSTOP)
439		return;
440	pti->pt_flags &= ~PF_STOPPED;
441	wakeup_other(tp, FREAD);
442}
443
444/* Wakes up the OTHER tty;*/
445static void
446wakeup_other(tp, flag)
447	struct tty *tp;
448	int flag;
449{
450	struct softpart *ourpart, *otherpart;
451
452	GETPARTS(tp, ourpart, otherpart);
453	if (flag & FREAD) {
454		selwakeup(&otherpart->nm_tty.t_rsel);
455		wakeup(TSA_PTC_READ((&otherpart->nm_tty)));
456	}
457	if (flag & FWRITE) {
458		selwakeup(&otherpart->nm_tty.t_wsel);
459		wakeup(TSA_PTC_WRITE((&otherpart->nm_tty)));
460	}
461}
462
463static	void
464nmdmstop(tp, flush)
465	register struct tty *tp;
466	int flush;
467{
468	struct nm_softc *pti = tp->t_dev->si_drv1;
469	int flag;
470
471	/* note: FLUSHREAD and FLUSHWRITE already ok */
472	if (flush == 0) {
473		flush = TIOCPKT_STOP;
474		pti->pt_flags |= PF_STOPPED;
475	} else
476		pti->pt_flags &= ~PF_STOPPED;
477	/* change of perspective */
478	flag = 0;
479	if (flush & FREAD)
480		flag |= FWRITE;
481	if (flush & FWRITE)
482		flag |= FREAD;
483	wakeup_other(tp, flag);
484}
485
486/*ARGSUSED*/
487static	int
488nmdmioctl(dev, cmd, data, flag, p)
489	dev_t dev;
490	u_long cmd;
491	caddr_t data;
492	int flag;
493	struct proc *p;
494{
495	register struct tty *tp = dev->si_tty;
496	struct nm_softc *pti = dev->si_drv1;
497	int error, s;
498	register struct tty *tp2;
499	struct softpart *ourpart, *otherpart;
500
501	s = spltty();
502	GETPARTS(tp, ourpart, otherpart);
503	tp2 = &otherpart->nm_tty;
504
505	error = (*linesw[tp->t_line].l_ioctl)(tp, cmd, data, flag, p);
506	if (error == ENOIOCTL)
507		 error = ttioctl(tp, cmd, data, flag);
508	if (error == ENOIOCTL) {
509		switch (cmd) {
510		case TIOCSBRK:
511			otherpart->gotbreak = 1;
512			break;
513		case TIOCCBRK:
514			break;
515		case TIOCSDTR:
516			ourpart->modemsignals |= TIOCM_DTR;
517			break;
518		case TIOCCDTR:
519			ourpart->modemsignals &= TIOCM_DTR;
520			break;
521		case TIOCMSET:
522			ourpart->modemsignals = *(int *)data;
523			otherpart->modemsignals = *(int *)data;
524			break;
525		case TIOCMBIS:
526			ourpart->modemsignals |= *(int *)data;
527			break;
528		case TIOCMBIC:
529			ourpart->modemsignals &= ~(*(int *)data);
530			otherpart->modemsignals &= ~(*(int *)data);
531			break;
532		case TIOCMGET:
533			*(int *)data = ourpart->modemsignals;
534			break;
535		case TIOCMSDTRWAIT:
536			break;
537		case TIOCMGDTRWAIT:
538			*(int *)data = 0;
539			break;
540		case TIOCTIMESTAMP:
541		case TIOCDCDTIMESTAMP:
542		default:
543			splx(s);
544			error = ENOTTY;
545			return (error);
546		}
547		error = 0;
548		nmdm_crossover(pti, ourpart, otherpart);
549	}
550	splx(s);
551	return (error);
552}
553
554static void
555nmdm_crossover(struct nm_softc *pti,
556		struct softpart *ourpart,
557		struct softpart *otherpart)
558{
559	otherpart->modemsignals &= ~(TIOCM_CTS|TIOCM_CAR);
560	if (ourpart->modemsignals & TIOCM_RTS)
561		otherpart->modemsignals |= TIOCM_CTS;
562	if (ourpart->modemsignals & TIOCM_DTR)
563		otherpart->modemsignals |= TIOCM_CAR;
564}
565
566
567
568static void nmdm_drvinit __P((void *unused));
569
570static void
571nmdm_drvinit(unused)
572	void *unused;
573{
574	cdevsw_add(&nmdm_cdevsw);
575	/* XXX: Gross hack for DEVFS */
576	nmdminit(0);
577}
578
579SYSINIT(nmdmdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,nmdm_drvinit,NULL)
580