xref: /dragonfly/sys/dev/misc/nmdm/nmdm.c (revision 6e285212) 
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: src/sys/dev/nmdm/nmdm.c,v 1.5.2.1 2001/08/11 00:54:14 mp Exp $
34  * $DragonFly: src/sys/dev/misc/nmdm/nmdm.c,v 1.2 2003/06/17 04:28:28 dillon Exp $
35  */
36 
37 /*
38  * Pseudo-nulmodem Driver
39  */
40 #include "opt_compat.h"
41 #include <sys/param.h>
42 #include <sys/systm.h>
43 #if defined(COMPAT_43) || defined(COMPAT_SUNOS)
44 #include <sys/ioctl_compat.h>
45 #endif
46 #include <sys/proc.h>
47 #include <sys/tty.h>
48 #include <sys/conf.h>
49 #include <sys/fcntl.h>
50 #include <sys/poll.h>
51 #include <sys/kernel.h>
52 #include <sys/vnode.h>
53 #include <sys/signalvar.h>
54 #include <sys/malloc.h>
55 
56 MALLOC_DEFINE(M_NLMDM, "nullmodem", "nullmodem data structures");
57 
58 static void nmdmstart __P((struct tty *tp));
59 static void nmdmstop __P((struct tty *tp, int rw));
60 static void wakeup_other __P((struct tty *tp, int flag));
61 static void nmdminit __P((int n));
62 
63 static	d_open_t	nmdmopen;
64 static	d_close_t	nmdmclose;
65 static	d_read_t	nmdmread;
66 static	d_write_t	nmdmwrite;
67 static	d_ioctl_t	nmdmioctl;
68 
69 #define	CDEV_MAJOR	18
70 static struct cdevsw nmdm_cdevsw = {
71 	/* open */	nmdmopen,
72 	/* close */	nmdmclose,
73 	/* read */	nmdmread,
74 	/* write */	nmdmwrite,
75 	/* ioctl */	nmdmioctl,
76 	/* poll */	ttypoll,
77 	/* mmap */	nommap,
78 	/* strategy */	nostrategy,
79 	/* name */	"pts",
80 	/* maj */	CDEV_MAJOR,
81 	/* dump */	nodump,
82 	/* psize */	nopsize,
83 	/* flags */	D_TTY,
84 	/* bmaj */	-1
85 };
86 
87 #define BUFSIZ 100		/* Chunk size iomoved to/from user */
88 
89 struct softpart {
90 	struct tty nm_tty;
91 	dev_t	dev;
92 	int	modemsignals;	/* bits defined in sys/ttycom.h */
93 	int	gotbreak;
94 };
95 
96 struct	nm_softc {
97 	int	pt_flags;
98 	struct softpart part1, part2;
99 	struct	prison *pt_prison;
100 };
101 
102 #define	PF_STOPPED	0x10		/* user told stopped */
103 
104 static void
105 nmdm_crossover(struct nm_softc *pti,
106 		struct softpart *ourpart,
107 		struct softpart *otherpart);
108 
109 #define GETPARTS(tp, ourpart, otherpart) \
110 do {	\
111 	struct nm_softc *pti = tp->t_dev->si_drv1; \
112 	if (tp == &pti->part1.nm_tty) { \
113 		ourpart = &pti->part1; \
114 		otherpart = &pti->part2; \
115 	} else { \
116 		ourpart = &pti->part2; \
117 		otherpart = &pti->part1; \
118 	}  \
119 } while (0)
120 
121 /*
122  * This function creates and initializes a pair of ttys.
123  */
124 static void
125 nmdminit(n)
126 	int n;
127 {
128 	dev_t dev1, dev2;
129 	struct nm_softc *pt;
130 
131 	/* For now we only map the lower 8 bits of the minor */
132 	if (n & ~0xff)
133 		return;
134 
135 	pt = malloc(sizeof(*pt), M_NLMDM, M_WAITOK);
136 	bzero(pt, sizeof(*pt));
137 	pt->part1.dev = dev1 = make_dev(&nmdm_cdevsw, n+n,
138 	    0, 0, 0666, "nmdm%dA", n);
139 	pt->part2.dev = dev2 = make_dev(&nmdm_cdevsw, n+n+1,
140 	    0, 0, 0666, "nmdm%dB", n);
141 
142 	dev1->si_drv1 = dev2->si_drv1 = pt;
143 	dev1->si_tty = &pt->part1.nm_tty;
144 	dev2->si_tty = &pt->part2.nm_tty;
145 	ttyregister(&pt->part1.nm_tty);
146 	ttyregister(&pt->part2.nm_tty);
147 	pt->part1.nm_tty.t_oproc = nmdmstart;
148 	pt->part2.nm_tty.t_oproc = nmdmstart;
149 	pt->part1.nm_tty.t_stop = nmdmstop;
150 	pt->part2.nm_tty.t_dev = dev1;
151 	pt->part1.nm_tty.t_dev = dev2;
152 	pt->part2.nm_tty.t_stop = nmdmstop;
153 }
154 
155 /*ARGSUSED*/
156 static	int
157 nmdmopen(dev, flag, devtype, p)
158 	dev_t dev;
159 	int flag, devtype;
160 	struct proc *p;
161 {
162 	register struct tty *tp, *tp2;
163 	int error;
164 	int minr;
165 	dev_t nextdev;
166 	struct nm_softc *pti;
167 	int is_b;
168 	int	pair;
169 	struct	softpart *ourpart, *otherpart;
170 
171 	/*
172 	 * XXX: Gross hack for DEVFS:
173 	 * If we openned this device, ensure we have the
174 	 * next one too, so people can open it.
175 	 */
176 	minr = lminor(dev);
177 	pair = minr >> 1;
178 	is_b = minr & 1;
179 
180 	if (pair < 127) {
181 		nextdev = makedev(major(dev), (pair+pair) + 1);
182 		if (!nextdev->si_drv1) {
183 			nmdminit(pair + 1);
184 		}
185 	}
186 	if (!dev->si_drv1)
187 		nmdminit(pair);
188 
189 	if (!dev->si_drv1)
190 		return(ENXIO);
191 
192 	pti = dev->si_drv1;
193 	if (is_b)
194 		tp = &pti->part2.nm_tty;
195 	else
196 		tp = &pti->part1.nm_tty;
197 	GETPARTS(tp, ourpart, otherpart);
198 	tp2 = &otherpart->nm_tty;
199 	ourpart->modemsignals |= TIOCM_LE;
200 
201 	if ((tp->t_state & TS_ISOPEN) == 0) {
202 		ttychars(tp);		/* Set up default chars */
203 		tp->t_iflag = TTYDEF_IFLAG;
204 		tp->t_oflag = TTYDEF_OFLAG;
205 		tp->t_lflag = TTYDEF_LFLAG;
206 		tp->t_cflag = TTYDEF_CFLAG;
207 		tp->t_ispeed = tp->t_ospeed = TTYDEF_SPEED;
208 	} else if (tp->t_state & TS_XCLUDE && suser(p)) {
209 		return (EBUSY);
210 	} else if (pti->pt_prison != p->p_prison) {
211 		return (EBUSY);
212 	}
213 
214 	/*
215 	 * If the other side is open we have carrier
216 	 */
217 	if (tp2->t_state & TS_ISOPEN) {
218 		(void)(*linesw[tp->t_line].l_modem)(tp, 1);
219 	}
220 
221 	/*
222 	 * And the other side gets carrier as we are now open.
223 	 */
224 	(void)(*linesw[tp2->t_line].l_modem)(tp2, 1);
225 
226 	/* External processing makes no sense here */
227 	tp->t_lflag &= ~EXTPROC;
228 
229 	/*
230 	 * Wait here if we don't have carrier.
231 	 */
232 #if 0
233 	while ((tp->t_state & TS_CARR_ON) == 0) {
234 		if (flag & FNONBLOCK)
235 			break;
236 		error = ttysleep(tp, TSA_CARR_ON(tp), TTIPRI | PCATCH,
237 				 "nmdopn", 0);
238 		if (error)
239 			return (error);
240 	}
241 #endif
242 
243 	/*
244 	 * Give the line disciplin a chance to set this end up.
245 	 */
246 	error = (*linesw[tp->t_line].l_open)(dev, tp);
247 
248 	/*
249 	 * Wake up the other side.
250 	 * Theoretically not needed.
251 	 */
252 	ourpart->modemsignals |= TIOCM_DTR;
253 	nmdm_crossover(pti, ourpart, otherpart);
254 	if (error == 0)
255 		wakeup_other(tp, FREAD|FWRITE); /* XXX */
256 	return (error);
257 }
258 
259 static	int
260 nmdmclose(dev, flag, mode, p)
261 	dev_t dev;
262 	int flag, mode;
263 	struct proc *p;
264 {
265 	register struct tty *tp, *tp2;
266 	int err;
267 	struct softpart *ourpart, *otherpart;
268 
269 	/*
270 	 * let the other end know that the game is up
271 	 */
272 	tp = dev->si_tty;
273 	GETPARTS(tp, ourpart, otherpart);
274 	tp2 = &otherpart->nm_tty;
275 	(void)(*linesw[tp2->t_line].l_modem)(tp2, 0);
276 
277 	/*
278 	 * XXX MDMBUF makes no sense for nmdms but would inhibit the above
279 	 * l_modem().  CLOCAL makes sense but isn't supported.   Special
280 	 * l_modem()s that ignore carrier drop make no sense for nmdms but
281 	 * may be in use because other parts of the line discipline make
282 	 * sense for nmdms.  Recover by doing everything that a normal
283 	 * ttymodem() would have done except for sending a SIGHUP.
284 	 */
285 	if (tp2->t_state & TS_ISOPEN) {
286 		tp2->t_state &= ~(TS_CARR_ON | TS_CONNECTED);
287 		tp2->t_state |= TS_ZOMBIE;
288 		ttyflush(tp2, FREAD | FWRITE);
289 	}
290 
291 	err = (*linesw[tp->t_line].l_close)(tp, flag);
292 	ourpart->modemsignals &= ~TIOCM_DTR;
293 	nmdm_crossover(dev->si_drv1, ourpart, otherpart);
294 	nmdmstop(tp, FREAD|FWRITE);
295 	(void) ttyclose(tp);
296 	return (err);
297 }
298 
299 static	int
300 nmdmread(dev, uio, flag)
301 	dev_t dev;
302 	struct uio *uio;
303 	int flag;
304 {
305 	int error = 0;
306 	struct tty *tp, *tp2;
307 	struct softpart *ourpart, *otherpart;
308 
309 	tp = dev->si_tty;
310 	GETPARTS(tp, ourpart, otherpart);
311 	tp2 = &otherpart->nm_tty;
312 
313 #if 0
314 	if (tp2->t_state & TS_ISOPEN) {
315 		error = (*linesw[tp->t_line].l_read)(tp, uio, flag);
316 		wakeup_other(tp, FWRITE);
317 	} else {
318 		if (flag & IO_NDELAY) {
319 			return (EWOULDBLOCK);
320 		}
321 		error = tsleep(TSA_PTC_READ(tp),
322 				TTIPRI | PCATCH, "nmdout", 0);
323 		}
324 	}
325 #else
326 	if ((error = (*linesw[tp->t_line].l_read)(tp, uio, flag)) == 0)
327 		wakeup_other(tp, FWRITE);
328 #endif
329 	return (error);
330 }
331 
332 /*
333  * Write to pseudo-tty.
334  * Wakeups of controlling tty will happen
335  * indirectly, when tty driver calls nmdmstart.
336  */
337 static	int
338 nmdmwrite(dev, uio, flag)
339 	dev_t dev;
340 	struct uio *uio;
341 	int flag;
342 {
343 	register u_char *cp = 0;
344 	register int cc = 0;
345 	u_char locbuf[BUFSIZ];
346 	int cnt = 0;
347 	int error = 0;
348 	struct tty *tp1, *tp;
349 	struct softpart *ourpart, *otherpart;
350 
351 	tp1 = dev->si_tty;
352 	/*
353 	 * Get the other tty struct.
354 	 * basically we are writing into the INPUT side of the other device.
355 	 */
356 	GETPARTS(tp1, ourpart, otherpart);
357 	tp = &otherpart->nm_tty;
358 
359 again:
360 	if ((tp->t_state & TS_ISOPEN) == 0)
361 		return (EIO);
362 	while (uio->uio_resid > 0 || cc > 0) {
363 		/*
364 		 * Fill up the buffer if it's empty
365 		 */
366 		if (cc == 0) {
367 			cc = min(uio->uio_resid, BUFSIZ);
368 			cp = locbuf;
369 			error = uiomove((caddr_t)cp, cc, uio);
370 			if (error)
371 				return (error);
372 			/* check again for safety */
373 			if ((tp->t_state & TS_ISOPEN) == 0) {
374 				/* adjust for data copied in but not written */
375 				uio->uio_resid += cc;
376 				return (EIO);
377 			}
378 		}
379 		while (cc > 0) {
380 			if (((tp->t_rawq.c_cc + tp->t_canq.c_cc) >= (TTYHOG-2))
381 			&& ((tp->t_canq.c_cc > 0) || !(tp->t_iflag&ICANON))) {
382 				/*
383 	 			 * Come here to wait for space in outq,
384 				 * or space in rawq, or an empty canq.
385 	 			 */
386 				wakeup(TSA_HUP_OR_INPUT(tp));
387 				if ((tp->t_state & TS_CONNECTED) == 0) {
388 					/*
389 					 * Data piled up because not connected.
390 					 * Adjust for data copied in but
391 					 * not written.
392 					 */
393 					uio->uio_resid += cc;
394 					return (EIO);
395 				}
396 				if (flag & IO_NDELAY) {
397 					/*
398 				         * Don't wait if asked not to.
399 					 * Adjust for data copied in but
400 					 * not written.
401 					 */
402 					uio->uio_resid += cc;
403 					if (cnt == 0)
404 						return (EWOULDBLOCK);
405 					return (0);
406 				}
407 				error = tsleep(TSA_PTC_WRITE(tp),
408 						TTOPRI | PCATCH, "nmdout", 0);
409 				if (error) {
410 					/*
411 					 * Tsleep returned (signal?).
412 					 * Go find out what the user wants.
413 					 * adjust for data copied in but
414 					 * not written
415 					 */
416 					uio->uio_resid += cc;
417 					return (error);
418 				}
419 				goto again;
420 			}
421 			(*linesw[tp->t_line].l_rint)(*cp++, tp);
422 			cnt++;
423 			cc--;
424 		}
425 		cc = 0;
426 	}
427 	return (0);
428 }
429 
430 /*
431  * Start output on pseudo-tty.
432  * Wake up process selecting or sleeping for input from controlling tty.
433  */
434 static void
435 nmdmstart(tp)
436 	struct tty *tp;
437 {
438 	register struct nm_softc *pti = tp->t_dev->si_drv1;
439 
440 	if (tp->t_state & TS_TTSTOP)
441 		return;
442 	pti->pt_flags &= ~PF_STOPPED;
443 	wakeup_other(tp, FREAD);
444 }
445 
446 /* Wakes up the OTHER tty;*/
447 static void
448 wakeup_other(tp, flag)
449 	struct tty *tp;
450 	int flag;
451 {
452 	struct softpart *ourpart, *otherpart;
453 
454 	GETPARTS(tp, ourpart, otherpart);
455 	if (flag & FREAD) {
456 		selwakeup(&otherpart->nm_tty.t_rsel);
457 		wakeup(TSA_PTC_READ((&otherpart->nm_tty)));
458 	}
459 	if (flag & FWRITE) {
460 		selwakeup(&otherpart->nm_tty.t_wsel);
461 		wakeup(TSA_PTC_WRITE((&otherpart->nm_tty)));
462 	}
463 }
464 
465 static	void
466 nmdmstop(tp, flush)
467 	register struct tty *tp;
468 	int flush;
469 {
470 	struct nm_softc *pti = tp->t_dev->si_drv1;
471 	int flag;
472 
473 	/* note: FLUSHREAD and FLUSHWRITE already ok */
474 	if (flush == 0) {
475 		flush = TIOCPKT_STOP;
476 		pti->pt_flags |= PF_STOPPED;
477 	} else
478 		pti->pt_flags &= ~PF_STOPPED;
479 	/* change of perspective */
480 	flag = 0;
481 	if (flush & FREAD)
482 		flag |= FWRITE;
483 	if (flush & FWRITE)
484 		flag |= FREAD;
485 	wakeup_other(tp, flag);
486 }
487 
488 /*ARGSUSED*/
489 static	int
490 nmdmioctl(dev, cmd, data, flag, p)
491 	dev_t dev;
492 	u_long cmd;
493 	caddr_t data;
494 	int flag;
495 	struct proc *p;
496 {
497 	register struct tty *tp = dev->si_tty;
498 	struct nm_softc *pti = dev->si_drv1;
499 	int error, s;
500 	register struct tty *tp2;
501 	struct softpart *ourpart, *otherpart;
502 
503 	s = spltty();
504 	GETPARTS(tp, ourpart, otherpart);
505 	tp2 = &otherpart->nm_tty;
506 
507 	error = (*linesw[tp->t_line].l_ioctl)(tp, cmd, data, flag, p);
508 	if (error == ENOIOCTL)
509 		 error = ttioctl(tp, cmd, data, flag);
510 	if (error == ENOIOCTL) {
511 		switch (cmd) {
512 		case TIOCSBRK:
513 			otherpart->gotbreak = 1;
514 			break;
515 		case TIOCCBRK:
516 			break;
517 		case TIOCSDTR:
518 			ourpart->modemsignals |= TIOCM_DTR;
519 			break;
520 		case TIOCCDTR:
521 			ourpart->modemsignals &= TIOCM_DTR;
522 			break;
523 		case TIOCMSET:
524 			ourpart->modemsignals = *(int *)data;
525 			otherpart->modemsignals = *(int *)data;
526 			break;
527 		case TIOCMBIS:
528 			ourpart->modemsignals |= *(int *)data;
529 			break;
530 		case TIOCMBIC:
531 			ourpart->modemsignals &= ~(*(int *)data);
532 			otherpart->modemsignals &= ~(*(int *)data);
533 			break;
534 		case TIOCMGET:
535 			*(int *)data = ourpart->modemsignals;
536 			break;
537 		case TIOCMSDTRWAIT:
538 			break;
539 		case TIOCMGDTRWAIT:
540 			*(int *)data = 0;
541 			break;
542 		case TIOCTIMESTAMP:
543 		case TIOCDCDTIMESTAMP:
544 		default:
545 			splx(s);
546 			error = ENOTTY;
547 			return (error);
548 		}
549 		error = 0;
550 		nmdm_crossover(pti, ourpart, otherpart);
551 	}
552 	splx(s);
553 	return (error);
554 }
555 
556 static void
557 nmdm_crossover(struct nm_softc *pti,
558 		struct softpart *ourpart,
559 		struct softpart *otherpart)
560 {
561 	otherpart->modemsignals &= ~(TIOCM_CTS|TIOCM_CAR);
562 	if (ourpart->modemsignals & TIOCM_RTS)
563 		otherpart->modemsignals |= TIOCM_CTS;
564 	if (ourpart->modemsignals & TIOCM_DTR)
565 		otherpart->modemsignals |= TIOCM_CAR;
566 }
567 
568 
569 
570 static void nmdm_drvinit __P((void *unused));
571 
572 static void
573 nmdm_drvinit(unused)
574 	void *unused;
575 {
576 	cdevsw_add(&nmdm_cdevsw);
577 	/* XXX: Gross hack for DEVFS */
578 	nmdminit(0);
579 }
580 
581 SYSINIT(nmdmdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,nmdm_drvinit,NULL)
582