xref: /dragonfly/sys/dev/misc/nmdm/nmdm.c (revision 1b722dce) 
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 1.16 2008/01/05 14:02:37 swildner 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/priv.h>
48 #include <sys/thread2.h>
49 #include <sys/tty.h>
50 #include <sys/conf.h>
51 #include <sys/fcntl.h>
52 #include <sys/poll.h>
53 #include <sys/kernel.h>
54 #include <sys/vnode.h>
55 #include <sys/signalvar.h>
56 #include <sys/malloc.h>
57 
58 MALLOC_DEFINE(M_NLMDM, "nullmodem", "nullmodem data structures");
59 
60 static void nmdmstart (struct tty *tp);
61 static void nmdmstop (struct tty *tp, int rw);
62 static void wakeup_other (struct tty *tp, int flag);
63 static void nmdminit (int n);
64 
65 static	d_open_t	nmdmopen;
66 static	d_close_t	nmdmclose;
67 static	d_read_t	nmdmread;
68 static	d_write_t	nmdmwrite;
69 static	d_ioctl_t	nmdmioctl;
70 
71 #define	CDEV_MAJOR	18
72 static struct dev_ops nmdm_ops = {
73 	{ "pts", CDEV_MAJOR, D_TTY },
74 	.d_open =	nmdmopen,
75 	.d_close =	nmdmclose,
76 	.d_read =	nmdmread,
77 	.d_write =	nmdmwrite,
78 	.d_ioctl =	nmdmioctl,
79 	.d_poll =	ttypoll,
80 	.d_revoke =	ttyrevoke
81 };
82 
83 #define BUFSIZ 100		/* Chunk size iomoved to/from user */
84 
85 struct softpart {
86 	struct tty nm_tty;
87 	cdev_t	dev;
88 	int	modemsignals;	/* bits defined in sys/ttycom.h */
89 	int	gotbreak;
90 };
91 
92 struct	nm_softc {
93 	int	pt_flags;
94 	struct softpart part1, part2;
95 	struct	prison *pt_prison;
96 };
97 
98 #define	PF_STOPPED	0x10		/* user told stopped */
99 
100 static void
101 nmdm_crossover(struct nm_softc *pti,
102 		struct softpart *ourpart,
103 		struct softpart *otherpart);
104 
105 #define GETPARTS(tp, ourpart, otherpart) \
106 do {	\
107 	struct nm_softc *pti = tp->t_dev->si_drv1; \
108 	if (tp == &pti->part1.nm_tty) { \
109 		ourpart = &pti->part1; \
110 		otherpart = &pti->part2; \
111 	} else { \
112 		ourpart = &pti->part2; \
113 		otherpart = &pti->part1; \
114 	}  \
115 } while (0)
116 
117 /*
118  * This function creates and initializes a pair of ttys.
119  */
120 static void
121 nmdminit(int n)
122 {
123 	cdev_t dev1, dev2;
124 	struct nm_softc *pt;
125 
126 	/*
127 	 * Simplified unit number, use low 8 bits of minor number
128 	 * (remember, the minor number mask is 0xffff00ff).
129 	 */
130 	if (n & ~0x7f)
131 		return;
132 
133 	pt = kmalloc(sizeof(*pt), M_NLMDM, M_WAITOK | M_ZERO);
134 	pt->part1.dev = dev1 = make_dev(&nmdm_ops, n << 1,
135 					0, 0, 0666, "nmdm%dA", n);
136 	pt->part2.dev = dev2 = make_dev(&nmdm_ops, (n << 1) + 1,
137 					0, 0, 0666, "nmdm%dB", n);
138 
139 	dev1->si_drv1 = dev2->si_drv1 = pt;
140 	dev1->si_tty = &pt->part1.nm_tty;
141 	dev2->si_tty = &pt->part2.nm_tty;
142 	ttyregister(&pt->part1.nm_tty);
143 	ttyregister(&pt->part2.nm_tty);
144 	pt->part1.nm_tty.t_oproc = nmdmstart;
145 	pt->part2.nm_tty.t_oproc = nmdmstart;
146 	pt->part1.nm_tty.t_stop = nmdmstop;
147 	pt->part2.nm_tty.t_dev = dev1;
148 	pt->part1.nm_tty.t_dev = dev2;
149 	pt->part2.nm_tty.t_stop = nmdmstop;
150 }
151 
152 /*ARGSUSED*/
153 static	int
154 nmdmopen(struct dev_open_args *ap)
155 {
156 	cdev_t dev = ap->a_head.a_dev;
157 	struct tty *tp, *tp2;
158 	int error;
159 	int minr;
160 #if 0
161 	cdev_t nextdev;
162 #endif
163 	struct nm_softc *pti;
164 	int is_b;
165 	int	pair;
166 	struct	softpart *ourpart, *otherpart;
167 
168 	minr = lminor(dev);
169 	pair = minr >> 1;
170 	is_b = minr & 1;
171 
172 #if 0
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 	if (pair < 127) {
179 		nextdev = makedev(major(dev), (pair+pair) + 1);
180 		if (!nextdev->si_drv1) {
181 			nmdminit(pair + 1);
182 		}
183 	}
184 #endif
185 	if (!dev->si_drv1)
186 		nmdminit(pair);
187 
188 	if (!dev->si_drv1)
189 		return(ENXIO);
190 
191 	pti = dev->si_drv1;
192 	if (is_b)
193 		tp = &pti->part2.nm_tty;
194 	else
195 		tp = &pti->part1.nm_tty;
196 	GETPARTS(tp, ourpart, otherpart);
197 	tp2 = &otherpart->nm_tty;
198 	ourpart->modemsignals |= TIOCM_LE;
199 
200 	if ((tp->t_state & TS_ISOPEN) == 0) {
201 		ttychars(tp);		/* Set up default chars */
202 		tp->t_iflag = TTYDEF_IFLAG;
203 		tp->t_oflag = TTYDEF_OFLAG;
204 		tp->t_lflag = TTYDEF_LFLAG;
205 		tp->t_cflag = TTYDEF_CFLAG;
206 		tp->t_ispeed = tp->t_ospeed = TTYDEF_SPEED;
207 	} else if (tp->t_state & TS_XCLUDE && priv_check_cred(ap->a_cred, PRIV_ROOT, 0)) {
208 		return (EBUSY);
209 	} else if (pti->pt_prison != ap->a_cred->cr_prison) {
210 		return (EBUSY);
211 	}
212 
213 	/*
214 	 * If the other side is open we have carrier
215 	 */
216 	if (tp2->t_state & TS_ISOPEN) {
217 		(void)(*linesw[tp->t_line].l_modem)(tp, 1);
218 	}
219 
220 	/*
221 	 * And the other side gets carrier as we are now open.
222 	 */
223 	(void)(*linesw[tp2->t_line].l_modem)(tp2, 1);
224 
225 	/* External processing makes no sense here */
226 	tp->t_lflag &= ~EXTPROC;
227 
228 	/*
229 	 * Wait here if we don't have carrier.
230 	 */
231 #if 0
232 	while ((tp->t_state & TS_CARR_ON) == 0) {
233 		if (flag & FNONBLOCK)
234 			break;
235 		error = ttysleep(tp, TSA_CARR_ON(tp), PCATCH, "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 
257 static int
258 nmdmclose(struct dev_close_args *ap)
259 {
260 	cdev_t dev = ap->a_head.a_dev;
261 	struct tty *tp, *tp2;
262 	int err;
263 	struct softpart *ourpart, *otherpart;
264 
265 	/*
266 	 * let the other end know that the game is up
267 	 */
268 	tp = dev->si_tty;
269 	GETPARTS(tp, ourpart, otherpart);
270 	tp2 = &otherpart->nm_tty;
271 	(void)(*linesw[tp2->t_line].l_modem)(tp2, 0);
272 
273 	/*
274 	 * XXX MDMBUF makes no sense for nmdms but would inhibit the above
275 	 * l_modem().  CLOCAL makes sense but isn't supported.   Special
276 	 * l_modem()s that ignore carrier drop make no sense for nmdms but
277 	 * may be in use because other parts of the line discipline make
278 	 * sense for nmdms.  Recover by doing everything that a normal
279 	 * ttymodem() would have done except for sending a SIGHUP.
280 	 */
281 	if (tp2->t_state & TS_ISOPEN) {
282 		tp2->t_state &= ~(TS_CARR_ON | TS_CONNECTED);
283 		tp2->t_state |= TS_ZOMBIE;
284 		ttyflush(tp2, FREAD | FWRITE);
285 	}
286 
287 	err = (*linesw[tp->t_line].l_close)(tp, ap->a_fflag);
288 	ourpart->modemsignals &= ~TIOCM_DTR;
289 	nmdm_crossover(dev->si_drv1, ourpart, otherpart);
290 	nmdmstop(tp, FREAD|FWRITE);
291 	(void) ttyclose(tp);
292 	return (err);
293 }
294 
295 static int
296 nmdmread(struct dev_read_args *ap)
297 {
298 	cdev_t dev = ap->a_head.a_dev;
299 	int error = 0;
300 	struct tty *tp, *tp2;
301 	struct softpart *ourpart, *otherpart;
302 
303 	tp = dev->si_tty;
304 	GETPARTS(tp, ourpart, otherpart);
305 	tp2 = &otherpart->nm_tty;
306 
307 #if 0
308 	if (tp2->t_state & TS_ISOPEN) {
309 		error = (*linesw[tp->t_line].l_read)(tp, ap->a_uio, flag);
310 		wakeup_other(tp, FWRITE);
311 	} else {
312 		if (flag & IO_NDELAY) {
313 			return (EWOULDBLOCK);
314 		}
315 		error = tsleep(TSA_PTC_READ(tp), PCATCH, "nmdout", 0);
316 		}
317 	}
318 #else
319 	if ((error = (*linesw[tp->t_line].l_read)(tp, ap->a_uio, ap->a_ioflag)) == 0)
320 		wakeup_other(tp, FWRITE);
321 #endif
322 	return (error);
323 }
324 
325 /*
326  * Write to pseudo-tty.
327  * Wakeups of controlling tty will happen
328  * indirectly, when tty driver calls nmdmstart.
329  */
330 static	int
331 nmdmwrite(struct dev_write_args *ap)
332 {
333 	cdev_t dev = ap->a_head.a_dev;
334 	struct uio *uio = ap->a_uio;
335 	u_char *cp = 0;
336 	size_t cc = 0;
337 	u_char locbuf[BUFSIZ];
338 	int cnt = 0;
339 	int error = 0;
340 	struct tty *tp1, *tp;
341 	struct softpart *ourpart, *otherpart;
342 
343 	tp1 = dev->si_tty;
344 	/*
345 	 * Get the other tty struct.
346 	 * basically we are writing into the INPUT side of the other device.
347 	 */
348 	GETPARTS(tp1, ourpart, otherpart);
349 	tp = &otherpart->nm_tty;
350 
351 again:
352 	if ((tp->t_state & TS_ISOPEN) == 0)
353 		return (EIO);
354 	while (uio->uio_resid > 0 || cc > 0) {
355 		/*
356 		 * Fill up the buffer if it's empty
357 		 */
358 		if (cc == 0) {
359 			cc = szmin(uio->uio_resid, BUFSIZ);
360 			cp = locbuf;
361 			error = uiomove((caddr_t)cp, cc, uio);
362 			if (error)
363 				return (error);
364 			/* check again for safety */
365 			if ((tp->t_state & TS_ISOPEN) == 0) {
366 				/* adjust for data copied in but not written */
367 				uio->uio_resid += cc;
368 				return (EIO);
369 			}
370 		}
371 		while (cc > 0) {
372 			if (((tp->t_rawq.c_cc + tp->t_canq.c_cc) >= (TTYHOG-2))
373 			&& ((tp->t_canq.c_cc > 0) || !(tp->t_iflag&ICANON))) {
374 				/*
375 	 			 * Come here to wait for space in outq,
376 				 * or space in rawq, or an empty canq.
377 	 			 */
378 				wakeup(TSA_HUP_OR_INPUT(tp));
379 				if ((tp->t_state & TS_CONNECTED) == 0) {
380 					/*
381 					 * Data piled up because not connected.
382 					 * Adjust for data copied in but
383 					 * not written.
384 					 */
385 					uio->uio_resid += cc;
386 					return (EIO);
387 				}
388 				if (ap->a_ioflag & IO_NDELAY) {
389 					/*
390 				         * Don't wait if asked not to.
391 					 * Adjust for data copied in but
392 					 * not written.
393 					 */
394 					uio->uio_resid += cc;
395 					if (cnt == 0)
396 						return (EWOULDBLOCK);
397 					return (0);
398 				}
399 				error = tsleep(TSA_PTC_WRITE(tp),
400 						PCATCH, "nmdout", 0);
401 				if (error) {
402 					/*
403 					 * Tsleep returned (signal?).
404 					 * Go find out what the user wants.
405 					 * adjust for data copied in but
406 					 * not written
407 					 */
408 					uio->uio_resid += cc;
409 					return (error);
410 				}
411 				goto again;
412 			}
413 			(*linesw[tp->t_line].l_rint)(*cp++, tp);
414 			cnt++;
415 			cc--;
416 		}
417 		cc = 0;
418 	}
419 	return (0);
420 }
421 
422 /*
423  * Start output on pseudo-tty.
424  * Wake up process selecting or sleeping for input from controlling tty.
425  */
426 static void
427 nmdmstart(struct tty *tp)
428 {
429 	struct nm_softc *pti = tp->t_dev->si_drv1;
430 
431 	if (tp->t_state & TS_TTSTOP)
432 		return;
433 	pti->pt_flags &= ~PF_STOPPED;
434 	wakeup_other(tp, FREAD);
435 }
436 
437 /* Wakes up the OTHER tty;*/
438 static void
439 wakeup_other(struct tty *tp, int flag)
440 {
441 	struct softpart *ourpart, *otherpart;
442 
443 	GETPARTS(tp, ourpart, otherpart);
444 	if (flag & FREAD) {
445 		selwakeup(&otherpart->nm_tty.t_rsel);
446 		wakeup(TSA_PTC_READ((&otherpart->nm_tty)));
447 	}
448 	if (flag & FWRITE) {
449 		selwakeup(&otherpart->nm_tty.t_wsel);
450 		wakeup(TSA_PTC_WRITE((&otherpart->nm_tty)));
451 	}
452 }
453 
454 static	void
455 nmdmstop(struct tty *tp, int flush)
456 {
457 	struct nm_softc *pti = tp->t_dev->si_drv1;
458 	int flag;
459 
460 	/* note: FLUSHREAD and FLUSHWRITE already ok */
461 	if (flush == 0) {
462 		flush = TIOCPKT_STOP;
463 		pti->pt_flags |= PF_STOPPED;
464 	} else
465 		pti->pt_flags &= ~PF_STOPPED;
466 	/* change of perspective */
467 	flag = 0;
468 	if (flush & FREAD)
469 		flag |= FWRITE;
470 	if (flush & FWRITE)
471 		flag |= FREAD;
472 	wakeup_other(tp, flag);
473 }
474 
475 /*ARGSUSED*/
476 static	int
477 nmdmioctl(struct dev_ioctl_args *ap)
478 {
479 	cdev_t dev = ap->a_head.a_dev;
480 	struct tty *tp = dev->si_tty;
481 	struct nm_softc *pti = dev->si_drv1;
482 	int error;
483 	struct tty *tp2;
484 	struct softpart *ourpart, *otherpart;
485 
486 	crit_enter();
487 	GETPARTS(tp, ourpart, otherpart);
488 	tp2 = &otherpart->nm_tty;
489 
490 	error = (*linesw[tp->t_line].l_ioctl)(tp, ap->a_cmd, ap->a_data,
491 					      ap->a_fflag, ap->a_cred);
492 	if (error == ENOIOCTL)
493 		 error = ttioctl(tp, ap->a_cmd, ap->a_data, ap->a_fflag);
494 	if (error == ENOIOCTL) {
495 		switch (ap->a_cmd) {
496 		case TIOCSBRK:
497 			otherpart->gotbreak = 1;
498 			break;
499 		case TIOCCBRK:
500 			break;
501 		case TIOCSDTR:
502 			ourpart->modemsignals |= TIOCM_DTR;
503 			break;
504 		case TIOCCDTR:
505 			ourpart->modemsignals &= TIOCM_DTR;
506 			break;
507 		case TIOCMSET:
508 			ourpart->modemsignals = *(int *)ap->a_data;
509 			otherpart->modemsignals = *(int *)ap->a_data;
510 			break;
511 		case TIOCMBIS:
512 			ourpart->modemsignals |= *(int *)ap->a_data;
513 			break;
514 		case TIOCMBIC:
515 			ourpart->modemsignals &= ~(*(int *)ap->a_data);
516 			otherpart->modemsignals &= ~(*(int *)ap->a_data);
517 			break;
518 		case TIOCMGET:
519 			*(int *)ap->a_data = ourpart->modemsignals;
520 			break;
521 		case TIOCMSDTRWAIT:
522 			break;
523 		case TIOCMGDTRWAIT:
524 			*(int *)ap->a_data = 0;
525 			break;
526 		case TIOCTIMESTAMP:
527 		case TIOCDCDTIMESTAMP:
528 		default:
529 			crit_exit();
530 			error = ENOTTY;
531 			return (error);
532 		}
533 		error = 0;
534 		nmdm_crossover(pti, ourpart, otherpart);
535 	}
536 	crit_exit();
537 	return (error);
538 }
539 
540 static void
541 nmdm_crossover(struct nm_softc *pti,
542 		struct softpart *ourpart,
543 		struct softpart *otherpart)
544 {
545 	otherpart->modemsignals &= ~(TIOCM_CTS|TIOCM_CAR);
546 	if (ourpart->modemsignals & TIOCM_RTS)
547 		otherpart->modemsignals |= TIOCM_CTS;
548 	if (ourpart->modemsignals & TIOCM_DTR)
549 		otherpart->modemsignals |= TIOCM_CAR;
550 }
551 
552 
553 
554 static void nmdm_drvinit (void *unused);
555 
556 static void
557 nmdm_drvinit(void *unused)
558 {
559 	/* XXX: Gross hack for DEVFS */
560 	nmdminit(0);
561 }
562 
563 SYSINIT(nmdmdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,nmdm_drvinit,NULL)
564