xref: /dragonfly/sys/dev/misc/nmdm/nmdm.c (revision 4e7eb5cc) 
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 1.8 2003/08/27 10:35:17 rob 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 (struct tty *tp);
59 static void nmdmstop (struct tty *tp, int rw);
60 static void wakeup_other (struct tty *tp, int flag);
61 static void nmdminit (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 	/* name */	"pts",
72 	/* maj */	CDEV_MAJOR,
73 	/* flags */	D_TTY,
74 	/* port */	NULL,
75 	/* autoq */	0,
76 
77 	/* open */	nmdmopen,
78 	/* close */	nmdmclose,
79 	/* read */	nmdmread,
80 	/* write */	nmdmwrite,
81 	/* ioctl */	nmdmioctl,
82 	/* poll */	ttypoll,
83 	/* mmap */	nommap,
84 	/* strategy */	nostrategy,
85 	/* dump */	nodump,
86 	/* psize */	nopsize
87 };
88 
89 #define BUFSIZ 100		/* Chunk size iomoved to/from user */
90 
91 struct softpart {
92 	struct tty nm_tty;
93 	dev_t	dev;
94 	int	modemsignals;	/* bits defined in sys/ttycom.h */
95 	int	gotbreak;
96 };
97 
98 struct	nm_softc {
99 	int	pt_flags;
100 	struct softpart part1, part2;
101 	struct	prison *pt_prison;
102 };
103 
104 #define	PF_STOPPED	0x10		/* user told stopped */
105 
106 static void
107 nmdm_crossover(struct nm_softc *pti,
108 		struct softpart *ourpart,
109 		struct softpart *otherpart);
110 
111 #define GETPARTS(tp, ourpart, otherpart) \
112 do {	\
113 	struct nm_softc *pti = tp->t_dev->si_drv1; \
114 	if (tp == &pti->part1.nm_tty) { \
115 		ourpart = &pti->part1; \
116 		otherpart = &pti->part2; \
117 	} else { \
118 		ourpart = &pti->part2; \
119 		otherpart = &pti->part1; \
120 	}  \
121 } while (0)
122 
123 /*
124  * This function creates and initializes a pair of ttys.
125  */
126 static void
127 nmdminit(n)
128 	int n;
129 {
130 	dev_t dev1, dev2;
131 	struct nm_softc *pt;
132 
133 	/* For now we only map the lower 8 bits of the minor */
134 	if (n & ~0xff)
135 		return;
136 
137 	pt = malloc(sizeof(*pt), M_NLMDM, M_WAITOK);
138 	bzero(pt, sizeof(*pt));
139 	pt->part1.dev = dev1 = make_dev(&nmdm_cdevsw, n+n,
140 	    0, 0, 0666, "nmdm%dA", n);
141 	pt->part2.dev = dev2 = make_dev(&nmdm_cdevsw, n+n+1,
142 	    0, 0, 0666, "nmdm%dB", n);
143 
144 	dev1->si_drv1 = dev2->si_drv1 = pt;
145 	dev1->si_tty = &pt->part1.nm_tty;
146 	dev2->si_tty = &pt->part2.nm_tty;
147 	ttyregister(&pt->part1.nm_tty);
148 	ttyregister(&pt->part2.nm_tty);
149 	pt->part1.nm_tty.t_oproc = nmdmstart;
150 	pt->part2.nm_tty.t_oproc = nmdmstart;
151 	pt->part1.nm_tty.t_stop = nmdmstop;
152 	pt->part2.nm_tty.t_dev = dev1;
153 	pt->part1.nm_tty.t_dev = dev2;
154 	pt->part2.nm_tty.t_stop = nmdmstop;
155 }
156 
157 /*ARGSUSED*/
158 static	int
159 nmdmopen(dev_t dev, int flag, int devtype, struct thread *td)
160 {
161 	struct proc *p = td->td_proc;
162 	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 	KKASSERT(p != NULL);
172 
173 	/*
174 	 * XXX: Gross hack for DEVFS:
175 	 * If we openned this device, ensure we have the
176 	 * next one too, so people can open it.
177 	 */
178 	minr = lminor(dev);
179 	pair = minr >> 1;
180 	is_b = minr & 1;
181 
182 	if (pair < 127) {
183 		nextdev = makedev(major(dev), (pair+pair) + 1);
184 		if (!nextdev->si_drv1) {
185 			nmdminit(pair + 1);
186 		}
187 	}
188 	if (!dev->si_drv1)
189 		nmdminit(pair);
190 
191 	if (!dev->si_drv1)
192 		return(ENXIO);
193 
194 	pti = dev->si_drv1;
195 	if (is_b)
196 		tp = &pti->part2.nm_tty;
197 	else
198 		tp = &pti->part1.nm_tty;
199 	GETPARTS(tp, ourpart, otherpart);
200 	tp2 = &otherpart->nm_tty;
201 	ourpart->modemsignals |= TIOCM_LE;
202 
203 	if ((tp->t_state & TS_ISOPEN) == 0) {
204 		ttychars(tp);		/* Set up default chars */
205 		tp->t_iflag = TTYDEF_IFLAG;
206 		tp->t_oflag = TTYDEF_OFLAG;
207 		tp->t_lflag = TTYDEF_LFLAG;
208 		tp->t_cflag = TTYDEF_CFLAG;
209 		tp->t_ispeed = tp->t_ospeed = TTYDEF_SPEED;
210 	} else if (tp->t_state & TS_XCLUDE && suser(td)) {
211 		return (EBUSY);
212 	} else if (pti->pt_prison != p->p_ucred->cr_prison) {
213 		return (EBUSY);
214 	}
215 
216 	/*
217 	 * If the other side is open we have carrier
218 	 */
219 	if (tp2->t_state & TS_ISOPEN) {
220 		(void)(*linesw[tp->t_line].l_modem)(tp, 1);
221 	}
222 
223 	/*
224 	 * And the other side gets carrier as we are now open.
225 	 */
226 	(void)(*linesw[tp2->t_line].l_modem)(tp2, 1);
227 
228 	/* External processing makes no sense here */
229 	tp->t_lflag &= ~EXTPROC;
230 
231 	/*
232 	 * Wait here if we don't have carrier.
233 	 */
234 #if 0
235 	while ((tp->t_state & TS_CARR_ON) == 0) {
236 		if (flag & FNONBLOCK)
237 			break;
238 		error = ttysleep(tp, TSA_CARR_ON(tp), PCATCH, "nmdopn", 0);
239 		if (error)
240 			return (error);
241 	}
242 #endif
243 
244 	/*
245 	 * Give the line disciplin a chance to set this end up.
246 	 */
247 	error = (*linesw[tp->t_line].l_open)(dev, tp);
248 
249 	/*
250 	 * Wake up the other side.
251 	 * Theoretically not needed.
252 	 */
253 	ourpart->modemsignals |= TIOCM_DTR;
254 	nmdm_crossover(pti, ourpart, otherpart);
255 	if (error == 0)
256 		wakeup_other(tp, FREAD|FWRITE); /* XXX */
257 	return (error);
258 }
259 
260 static	int
261 nmdmclose(dev_t dev, int flag, int mode, struct thread *td)
262 {
263 	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 
297 static	int
298 nmdmread(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), PCATCH, "nmdout", 0);
320 		}
321 	}
322 #else
323 	if ((error = (*linesw[tp->t_line].l_read)(tp, uio, flag)) == 0)
324 		wakeup_other(tp, FWRITE);
325 #endif
326 	return (error);
327 }
328 
329 /*
330  * Write to pseudo-tty.
331  * Wakeups of controlling tty will happen
332  * indirectly, when tty driver calls nmdmstart.
333  */
334 static	int
335 nmdmwrite(dev, uio, flag)
336 	dev_t dev;
337 	struct uio *uio;
338 	int flag;
339 {
340 	u_char *cp = 0;
341 	int cc = 0;
342 	u_char locbuf[BUFSIZ];
343 	int cnt = 0;
344 	int error = 0;
345 	struct tty *tp1, *tp;
346 	struct softpart *ourpart, *otherpart;
347 
348 	tp1 = dev->si_tty;
349 	/*
350 	 * Get the other tty struct.
351 	 * basically we are writing into the INPUT side of the other device.
352 	 */
353 	GETPARTS(tp1, ourpart, otherpart);
354 	tp = &otherpart->nm_tty;
355 
356 again:
357 	if ((tp->t_state & TS_ISOPEN) == 0)
358 		return (EIO);
359 	while (uio->uio_resid > 0 || cc > 0) {
360 		/*
361 		 * Fill up the buffer if it's empty
362 		 */
363 		if (cc == 0) {
364 			cc = min(uio->uio_resid, BUFSIZ);
365 			cp = locbuf;
366 			error = uiomove((caddr_t)cp, cc, uio);
367 			if (error)
368 				return (error);
369 			/* check again for safety */
370 			if ((tp->t_state & TS_ISOPEN) == 0) {
371 				/* adjust for data copied in but not written */
372 				uio->uio_resid += cc;
373 				return (EIO);
374 			}
375 		}
376 		while (cc > 0) {
377 			if (((tp->t_rawq.c_cc + tp->t_canq.c_cc) >= (TTYHOG-2))
378 			&& ((tp->t_canq.c_cc > 0) || !(tp->t_iflag&ICANON))) {
379 				/*
380 	 			 * Come here to wait for space in outq,
381 				 * or space in rawq, or an empty canq.
382 	 			 */
383 				wakeup(TSA_HUP_OR_INPUT(tp));
384 				if ((tp->t_state & TS_CONNECTED) == 0) {
385 					/*
386 					 * Data piled up because not connected.
387 					 * Adjust for data copied in but
388 					 * not written.
389 					 */
390 					uio->uio_resid += cc;
391 					return (EIO);
392 				}
393 				if (flag & IO_NDELAY) {
394 					/*
395 				         * Don't wait if asked not to.
396 					 * Adjust for data copied in but
397 					 * not written.
398 					 */
399 					uio->uio_resid += cc;
400 					if (cnt == 0)
401 						return (EWOULDBLOCK);
402 					return (0);
403 				}
404 				error = tsleep(TSA_PTC_WRITE(tp),
405 						PCATCH, "nmdout", 0);
406 				if (error) {
407 					/*
408 					 * Tsleep returned (signal?).
409 					 * Go find out what the user wants.
410 					 * adjust for data copied in but
411 					 * not written
412 					 */
413 					uio->uio_resid += cc;
414 					return (error);
415 				}
416 				goto again;
417 			}
418 			(*linesw[tp->t_line].l_rint)(*cp++, tp);
419 			cnt++;
420 			cc--;
421 		}
422 		cc = 0;
423 	}
424 	return (0);
425 }
426 
427 /*
428  * Start output on pseudo-tty.
429  * Wake up process selecting or sleeping for input from controlling tty.
430  */
431 static void
432 nmdmstart(tp)
433 	struct tty *tp;
434 {
435 	struct nm_softc *pti = tp->t_dev->si_drv1;
436 
437 	if (tp->t_state & TS_TTSTOP)
438 		return;
439 	pti->pt_flags &= ~PF_STOPPED;
440 	wakeup_other(tp, FREAD);
441 }
442 
443 /* Wakes up the OTHER tty;*/
444 static void
445 wakeup_other(tp, flag)
446 	struct tty *tp;
447 	int flag;
448 {
449 	struct softpart *ourpart, *otherpart;
450 
451 	GETPARTS(tp, ourpart, otherpart);
452 	if (flag & FREAD) {
453 		selwakeup(&otherpart->nm_tty.t_rsel);
454 		wakeup(TSA_PTC_READ((&otherpart->nm_tty)));
455 	}
456 	if (flag & FWRITE) {
457 		selwakeup(&otherpart->nm_tty.t_wsel);
458 		wakeup(TSA_PTC_WRITE((&otherpart->nm_tty)));
459 	}
460 }
461 
462 static	void
463 nmdmstop(tp, flush)
464 	struct tty *tp;
465 	int flush;
466 {
467 	struct nm_softc *pti = tp->t_dev->si_drv1;
468 	int flag;
469 
470 	/* note: FLUSHREAD and FLUSHWRITE already ok */
471 	if (flush == 0) {
472 		flush = TIOCPKT_STOP;
473 		pti->pt_flags |= PF_STOPPED;
474 	} else
475 		pti->pt_flags &= ~PF_STOPPED;
476 	/* change of perspective */
477 	flag = 0;
478 	if (flush & FREAD)
479 		flag |= FWRITE;
480 	if (flush & FWRITE)
481 		flag |= FREAD;
482 	wakeup_other(tp, flag);
483 }
484 
485 /*ARGSUSED*/
486 static	int
487 nmdmioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct thread *td)
488 {
489 	struct tty *tp = dev->si_tty;
490 	struct nm_softc *pti = dev->si_drv1;
491 	int error, s;
492 	struct tty *tp2;
493 	struct softpart *ourpart, *otherpart;
494 
495 	s = spltty();
496 	GETPARTS(tp, ourpart, otherpart);
497 	tp2 = &otherpart->nm_tty;
498 
499 	error = (*linesw[tp->t_line].l_ioctl)(tp, cmd, data, flag, td);
500 	if (error == ENOIOCTL)
501 		 error = ttioctl(tp, cmd, data, flag);
502 	if (error == ENOIOCTL) {
503 		switch (cmd) {
504 		case TIOCSBRK:
505 			otherpart->gotbreak = 1;
506 			break;
507 		case TIOCCBRK:
508 			break;
509 		case TIOCSDTR:
510 			ourpart->modemsignals |= TIOCM_DTR;
511 			break;
512 		case TIOCCDTR:
513 			ourpart->modemsignals &= TIOCM_DTR;
514 			break;
515 		case TIOCMSET:
516 			ourpart->modemsignals = *(int *)data;
517 			otherpart->modemsignals = *(int *)data;
518 			break;
519 		case TIOCMBIS:
520 			ourpart->modemsignals |= *(int *)data;
521 			break;
522 		case TIOCMBIC:
523 			ourpart->modemsignals &= ~(*(int *)data);
524 			otherpart->modemsignals &= ~(*(int *)data);
525 			break;
526 		case TIOCMGET:
527 			*(int *)data = ourpart->modemsignals;
528 			break;
529 		case TIOCMSDTRWAIT:
530 			break;
531 		case TIOCMGDTRWAIT:
532 			*(int *)data = 0;
533 			break;
534 		case TIOCTIMESTAMP:
535 		case TIOCDCDTIMESTAMP:
536 		default:
537 			splx(s);
538 			error = ENOTTY;
539 			return (error);
540 		}
541 		error = 0;
542 		nmdm_crossover(pti, ourpart, otherpart);
543 	}
544 	splx(s);
545 	return (error);
546 }
547 
548 static void
549 nmdm_crossover(struct nm_softc *pti,
550 		struct softpart *ourpart,
551 		struct softpart *otherpart)
552 {
553 	otherpart->modemsignals &= ~(TIOCM_CTS|TIOCM_CAR);
554 	if (ourpart->modemsignals & TIOCM_RTS)
555 		otherpart->modemsignals |= TIOCM_CTS;
556 	if (ourpart->modemsignals & TIOCM_DTR)
557 		otherpart->modemsignals |= TIOCM_CAR;
558 }
559 
560 
561 
562 static void nmdm_drvinit (void *unused);
563 
564 static void
565 nmdm_drvinit(unused)
566 	void *unused;
567 {
568 	cdevsw_add(&nmdm_cdevsw);
569 	/* XXX: Gross hack for DEVFS */
570 	nmdminit(0);
571 }
572 
573 SYSINIT(nmdmdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,nmdm_drvinit,NULL)
574