xref: /dragonfly/sys/dev/misc/nmdm/nmdm.c (revision 27f48495) 
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 1.10 2004/05/19 22:52:43 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 (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 	/* clone */	NULL,
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 	/*
134 	 * Simplified unit number, use low 8 bits of minor number
135 	 * (remember, the minor number mask is 0xffff00ff).
136 	 */
137 	if (n & ~0x7f)
138 		return;
139 
140 	pt = malloc(sizeof(*pt), M_NLMDM, M_WAITOK);
141 	bzero(pt, sizeof(*pt));
142 	cdevsw_add(&nmdm_cdevsw, ~1, n << 1);
143 	pt->part1.dev = dev1 = make_dev(&nmdm_cdevsw, n << 1,
144 	    0, 0, 0666, "nmdm%dA", n);
145 	pt->part2.dev = dev2 = make_dev(&nmdm_cdevsw, (n << 1) + 1,
146 	    0, 0, 0666, "nmdm%dB", n);
147 
148 	dev1->si_drv1 = dev2->si_drv1 = pt;
149 	dev1->si_tty = &pt->part1.nm_tty;
150 	dev2->si_tty = &pt->part2.nm_tty;
151 	ttyregister(&pt->part1.nm_tty);
152 	ttyregister(&pt->part2.nm_tty);
153 	pt->part1.nm_tty.t_oproc = nmdmstart;
154 	pt->part2.nm_tty.t_oproc = nmdmstart;
155 	pt->part1.nm_tty.t_stop = nmdmstop;
156 	pt->part2.nm_tty.t_dev = dev1;
157 	pt->part1.nm_tty.t_dev = dev2;
158 	pt->part2.nm_tty.t_stop = nmdmstop;
159 }
160 
161 /*ARGSUSED*/
162 static	int
163 nmdmopen(dev_t dev, int flag, int devtype, struct thread *td)
164 {
165 	struct proc *p = td->td_proc;
166 	struct tty *tp, *tp2;
167 	int error;
168 	int minr;
169 #if 0
170 	dev_t nextdev;
171 #endif
172 	struct nm_softc *pti;
173 	int is_b;
174 	int	pair;
175 	struct	softpart *ourpart, *otherpart;
176 
177 	KKASSERT(p != NULL);
178 
179 	minr = lminor(dev);
180 	pair = minr >> 1;
181 	is_b = minr & 1;
182 
183 #if 0
184 	/*
185 	 * XXX: Gross hack for DEVFS:
186 	 * If we openned this device, ensure we have the
187 	 * next one too, so people can open it.
188 	 */
189 	if (pair < 127) {
190 		nextdev = makedev(major(dev), (pair+pair) + 1);
191 		if (!nextdev->si_drv1) {
192 			nmdminit(pair + 1);
193 		}
194 	}
195 #endif
196 	if (!dev->si_drv1)
197 		nmdminit(pair);
198 
199 	if (!dev->si_drv1)
200 		return(ENXIO);
201 
202 	pti = dev->si_drv1;
203 	if (is_b)
204 		tp = &pti->part2.nm_tty;
205 	else
206 		tp = &pti->part1.nm_tty;
207 	GETPARTS(tp, ourpart, otherpart);
208 	tp2 = &otherpart->nm_tty;
209 	ourpart->modemsignals |= TIOCM_LE;
210 
211 	if ((tp->t_state & TS_ISOPEN) == 0) {
212 		ttychars(tp);		/* Set up default chars */
213 		tp->t_iflag = TTYDEF_IFLAG;
214 		tp->t_oflag = TTYDEF_OFLAG;
215 		tp->t_lflag = TTYDEF_LFLAG;
216 		tp->t_cflag = TTYDEF_CFLAG;
217 		tp->t_ispeed = tp->t_ospeed = TTYDEF_SPEED;
218 	} else if (tp->t_state & TS_XCLUDE && suser(td)) {
219 		return (EBUSY);
220 	} else if (pti->pt_prison != p->p_ucred->cr_prison) {
221 		return (EBUSY);
222 	}
223 
224 	/*
225 	 * If the other side is open we have carrier
226 	 */
227 	if (tp2->t_state & TS_ISOPEN) {
228 		(void)(*linesw[tp->t_line].l_modem)(tp, 1);
229 	}
230 
231 	/*
232 	 * And the other side gets carrier as we are now open.
233 	 */
234 	(void)(*linesw[tp2->t_line].l_modem)(tp2, 1);
235 
236 	/* External processing makes no sense here */
237 	tp->t_lflag &= ~EXTPROC;
238 
239 	/*
240 	 * Wait here if we don't have carrier.
241 	 */
242 #if 0
243 	while ((tp->t_state & TS_CARR_ON) == 0) {
244 		if (flag & FNONBLOCK)
245 			break;
246 		error = ttysleep(tp, TSA_CARR_ON(tp), PCATCH, "nmdopn", 0);
247 		if (error)
248 			return (error);
249 	}
250 #endif
251 
252 	/*
253 	 * Give the line disciplin a chance to set this end up.
254 	 */
255 	error = (*linesw[tp->t_line].l_open)(dev, tp);
256 
257 	/*
258 	 * Wake up the other side.
259 	 * Theoretically not needed.
260 	 */
261 	ourpart->modemsignals |= TIOCM_DTR;
262 	nmdm_crossover(pti, ourpart, otherpart);
263 	if (error == 0)
264 		wakeup_other(tp, FREAD|FWRITE); /* XXX */
265 	return (error);
266 }
267 
268 static	int
269 nmdmclose(dev_t dev, int flag, int mode, struct thread *td)
270 {
271 	struct tty *tp, *tp2;
272 	int err;
273 	struct softpart *ourpart, *otherpart;
274 
275 	/*
276 	 * let the other end know that the game is up
277 	 */
278 	tp = dev->si_tty;
279 	GETPARTS(tp, ourpart, otherpart);
280 	tp2 = &otherpart->nm_tty;
281 	(void)(*linesw[tp2->t_line].l_modem)(tp2, 0);
282 
283 	/*
284 	 * XXX MDMBUF makes no sense for nmdms but would inhibit the above
285 	 * l_modem().  CLOCAL makes sense but isn't supported.   Special
286 	 * l_modem()s that ignore carrier drop make no sense for nmdms but
287 	 * may be in use because other parts of the line discipline make
288 	 * sense for nmdms.  Recover by doing everything that a normal
289 	 * ttymodem() would have done except for sending a SIGHUP.
290 	 */
291 	if (tp2->t_state & TS_ISOPEN) {
292 		tp2->t_state &= ~(TS_CARR_ON | TS_CONNECTED);
293 		tp2->t_state |= TS_ZOMBIE;
294 		ttyflush(tp2, FREAD | FWRITE);
295 	}
296 
297 	err = (*linesw[tp->t_line].l_close)(tp, flag);
298 	ourpart->modemsignals &= ~TIOCM_DTR;
299 	nmdm_crossover(dev->si_drv1, ourpart, otherpart);
300 	nmdmstop(tp, FREAD|FWRITE);
301 	(void) ttyclose(tp);
302 	return (err);
303 }
304 
305 static	int
306 nmdmread(dev, uio, flag)
307 	dev_t dev;
308 	struct uio *uio;
309 	int flag;
310 {
311 	int error = 0;
312 	struct tty *tp, *tp2;
313 	struct softpart *ourpart, *otherpart;
314 
315 	tp = dev->si_tty;
316 	GETPARTS(tp, ourpart, otherpart);
317 	tp2 = &otherpart->nm_tty;
318 
319 #if 0
320 	if (tp2->t_state & TS_ISOPEN) {
321 		error = (*linesw[tp->t_line].l_read)(tp, uio, flag);
322 		wakeup_other(tp, FWRITE);
323 	} else {
324 		if (flag & IO_NDELAY) {
325 			return (EWOULDBLOCK);
326 		}
327 		error = tsleep(TSA_PTC_READ(tp), PCATCH, "nmdout", 0);
328 		}
329 	}
330 #else
331 	if ((error = (*linesw[tp->t_line].l_read)(tp, uio, flag)) == 0)
332 		wakeup_other(tp, FWRITE);
333 #endif
334 	return (error);
335 }
336 
337 /*
338  * Write to pseudo-tty.
339  * Wakeups of controlling tty will happen
340  * indirectly, when tty driver calls nmdmstart.
341  */
342 static	int
343 nmdmwrite(dev, uio, flag)
344 	dev_t dev;
345 	struct uio *uio;
346 	int flag;
347 {
348 	u_char *cp = 0;
349 	int cc = 0;
350 	u_char locbuf[BUFSIZ];
351 	int cnt = 0;
352 	int error = 0;
353 	struct tty *tp1, *tp;
354 	struct softpart *ourpart, *otherpart;
355 
356 	tp1 = dev->si_tty;
357 	/*
358 	 * Get the other tty struct.
359 	 * basically we are writing into the INPUT side of the other device.
360 	 */
361 	GETPARTS(tp1, ourpart, otherpart);
362 	tp = &otherpart->nm_tty;
363 
364 again:
365 	if ((tp->t_state & TS_ISOPEN) == 0)
366 		return (EIO);
367 	while (uio->uio_resid > 0 || cc > 0) {
368 		/*
369 		 * Fill up the buffer if it's empty
370 		 */
371 		if (cc == 0) {
372 			cc = min(uio->uio_resid, BUFSIZ);
373 			cp = locbuf;
374 			error = uiomove((caddr_t)cp, cc, uio);
375 			if (error)
376 				return (error);
377 			/* check again for safety */
378 			if ((tp->t_state & TS_ISOPEN) == 0) {
379 				/* adjust for data copied in but not written */
380 				uio->uio_resid += cc;
381 				return (EIO);
382 			}
383 		}
384 		while (cc > 0) {
385 			if (((tp->t_rawq.c_cc + tp->t_canq.c_cc) >= (TTYHOG-2))
386 			&& ((tp->t_canq.c_cc > 0) || !(tp->t_iflag&ICANON))) {
387 				/*
388 	 			 * Come here to wait for space in outq,
389 				 * or space in rawq, or an empty canq.
390 	 			 */
391 				wakeup(TSA_HUP_OR_INPUT(tp));
392 				if ((tp->t_state & TS_CONNECTED) == 0) {
393 					/*
394 					 * Data piled up because not connected.
395 					 * Adjust for data copied in but
396 					 * not written.
397 					 */
398 					uio->uio_resid += cc;
399 					return (EIO);
400 				}
401 				if (flag & IO_NDELAY) {
402 					/*
403 				         * Don't wait if asked not to.
404 					 * Adjust for data copied in but
405 					 * not written.
406 					 */
407 					uio->uio_resid += cc;
408 					if (cnt == 0)
409 						return (EWOULDBLOCK);
410 					return (0);
411 				}
412 				error = tsleep(TSA_PTC_WRITE(tp),
413 						PCATCH, "nmdout", 0);
414 				if (error) {
415 					/*
416 					 * Tsleep returned (signal?).
417 					 * Go find out what the user wants.
418 					 * adjust for data copied in but
419 					 * not written
420 					 */
421 					uio->uio_resid += cc;
422 					return (error);
423 				}
424 				goto again;
425 			}
426 			(*linesw[tp->t_line].l_rint)(*cp++, tp);
427 			cnt++;
428 			cc--;
429 		}
430 		cc = 0;
431 	}
432 	return (0);
433 }
434 
435 /*
436  * Start output on pseudo-tty.
437  * Wake up process selecting or sleeping for input from controlling tty.
438  */
439 static void
440 nmdmstart(tp)
441 	struct tty *tp;
442 {
443 	struct nm_softc *pti = tp->t_dev->si_drv1;
444 
445 	if (tp->t_state & TS_TTSTOP)
446 		return;
447 	pti->pt_flags &= ~PF_STOPPED;
448 	wakeup_other(tp, FREAD);
449 }
450 
451 /* Wakes up the OTHER tty;*/
452 static void
453 wakeup_other(tp, flag)
454 	struct tty *tp;
455 	int flag;
456 {
457 	struct softpart *ourpart, *otherpart;
458 
459 	GETPARTS(tp, ourpart, otherpart);
460 	if (flag & FREAD) {
461 		selwakeup(&otherpart->nm_tty.t_rsel);
462 		wakeup(TSA_PTC_READ((&otherpart->nm_tty)));
463 	}
464 	if (flag & FWRITE) {
465 		selwakeup(&otherpart->nm_tty.t_wsel);
466 		wakeup(TSA_PTC_WRITE((&otherpart->nm_tty)));
467 	}
468 }
469 
470 static	void
471 nmdmstop(tp, flush)
472 	struct tty *tp;
473 	int flush;
474 {
475 	struct nm_softc *pti = tp->t_dev->si_drv1;
476 	int flag;
477 
478 	/* note: FLUSHREAD and FLUSHWRITE already ok */
479 	if (flush == 0) {
480 		flush = TIOCPKT_STOP;
481 		pti->pt_flags |= PF_STOPPED;
482 	} else
483 		pti->pt_flags &= ~PF_STOPPED;
484 	/* change of perspective */
485 	flag = 0;
486 	if (flush & FREAD)
487 		flag |= FWRITE;
488 	if (flush & FWRITE)
489 		flag |= FREAD;
490 	wakeup_other(tp, flag);
491 }
492 
493 /*ARGSUSED*/
494 static	int
495 nmdmioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct thread *td)
496 {
497 	struct tty *tp = dev->si_tty;
498 	struct nm_softc *pti = dev->si_drv1;
499 	int error, s;
500 	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, td);
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 (void *unused);
571 
572 static void
573 nmdm_drvinit(unused)
574 	void *unused;
575 {
576 	/* XXX: Gross hack for DEVFS */
577 	nmdminit(0);
578 }
579 
580 SYSINIT(nmdmdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,nmdm_drvinit,NULL)
581