xref: /dflybsd-src/sys/dev/misc/nmdm/nmdm.c (revision 6b7a5535fa94823cd77e8a3a626a4ebd0e4a1345) 
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 	dev_ops_add(&nmdm_ops, ~1, n << 1);
135 	pt->part1.dev = dev1 = make_dev(&nmdm_ops, n << 1,
136 	    0, 0, 0666, "nmdm%dA", n);
137 	pt->part2.dev = dev2 = make_dev(&nmdm_ops, (n << 1) + 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*/
154 static	int
155 nmdmopen(struct dev_open_args *ap)
156 {
157 	cdev_t dev = ap->a_head.a_dev;
158 	struct tty *tp, *tp2;
159 	int error;
160 	int minr;
161 #if 0
162 	cdev_t nextdev;
163 #endif
164 	struct nm_softc *pti;
165 	int is_b;
166 	int	pair;
167 	struct	softpart *ourpart, *otherpart;
168 
169 	minr = lminor(dev);
170 	pair = minr >> 1;
171 	is_b = minr & 1;
172 
173 #if 0
174 	/*
175 	 * XXX: Gross hack for DEVFS:
176 	 * If we openned this device, ensure we have the
177 	 * next one too, so people can open it.
178 	 */
179 	if (pair < 127) {
180 		nextdev = makedev(major(dev), (pair+pair) + 1);
181 		if (!nextdev->si_drv1) {
182 			nmdminit(pair + 1);
183 		}
184 	}
185 #endif
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 && priv_check_cred(ap->a_cred, PRIV_ROOT, 0)) {
209 		return (EBUSY);
210 	} else if (pti->pt_prison != ap->a_cred->cr_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), PCATCH, "nmdopn", 0);
237 		if (error)
238 			return (error);
239 	}
240 #endif
241 
242 	/*
243 	 * Give the line disciplin a chance to set this end up.
244 	 */
245 	error = (*linesw[tp->t_line].l_open)(dev, tp);
246 
247 	/*
248 	 * Wake up the other side.
249 	 * Theoretically not needed.
250 	 */
251 	ourpart->modemsignals |= TIOCM_DTR;
252 	nmdm_crossover(pti, ourpart, otherpart);
253 	if (error == 0)
254 		wakeup_other(tp, FREAD|FWRITE); /* XXX */
255 	return (error);
256 }
257 
258 static int
259 nmdmclose(struct dev_close_args *ap)
260 {
261 	cdev_t dev = ap->a_head.a_dev;
262 	struct tty *tp, *tp2;
263 	int err;
264 	struct softpart *ourpart, *otherpart;
265 
266 	/*
267 	 * let the other end know that the game is up
268 	 */
269 	tp = dev->si_tty;
270 	GETPARTS(tp, ourpart, otherpart);
271 	tp2 = &otherpart->nm_tty;
272 	(void)(*linesw[tp2->t_line].l_modem)(tp2, 0);
273 
274 	/*
275 	 * XXX MDMBUF makes no sense for nmdms but would inhibit the above
276 	 * l_modem().  CLOCAL makes sense but isn't supported.   Special
277 	 * l_modem()s that ignore carrier drop make no sense for nmdms but
278 	 * may be in use because other parts of the line discipline make
279 	 * sense for nmdms.  Recover by doing everything that a normal
280 	 * ttymodem() would have done except for sending a SIGHUP.
281 	 */
282 	if (tp2->t_state & TS_ISOPEN) {
283 		tp2->t_state &= ~(TS_CARR_ON | TS_CONNECTED);
284 		tp2->t_state |= TS_ZOMBIE;
285 		ttyflush(tp2, FREAD | FWRITE);
286 	}
287 
288 	err = (*linesw[tp->t_line].l_close)(tp, ap->a_fflag);
289 	ourpart->modemsignals &= ~TIOCM_DTR;
290 	nmdm_crossover(dev->si_drv1, ourpart, otherpart);
291 	nmdmstop(tp, FREAD|FWRITE);
292 	(void) ttyclose(tp);
293 	return (err);
294 }
295 
296 static int
297 nmdmread(struct dev_read_args *ap)
298 {
299 	cdev_t dev = ap->a_head.a_dev;
300 	int error = 0;
301 	struct tty *tp, *tp2;
302 	struct softpart *ourpart, *otherpart;
303 
304 	tp = dev->si_tty;
305 	GETPARTS(tp, ourpart, otherpart);
306 	tp2 = &otherpart->nm_tty;
307 
308 #if 0
309 	if (tp2->t_state & TS_ISOPEN) {
310 		error = (*linesw[tp->t_line].l_read)(tp, ap->a_uio, flag);
311 		wakeup_other(tp, FWRITE);
312 	} else {
313 		if (flag & IO_NDELAY) {
314 			return (EWOULDBLOCK);
315 		}
316 		error = tsleep(TSA_PTC_READ(tp), PCATCH, "nmdout", 0);
317 		}
318 	}
319 #else
320 	if ((error = (*linesw[tp->t_line].l_read)(tp, ap->a_uio, ap->a_ioflag)) == 0)
321 		wakeup_other(tp, FWRITE);
322 #endif
323 	return (error);
324 }
325 
326 /*
327  * Write to pseudo-tty.
328  * Wakeups of controlling tty will happen
329  * indirectly, when tty driver calls nmdmstart.
330  */
331 static	int
332 nmdmwrite(struct dev_write_args *ap)
333 {
334 	cdev_t dev = ap->a_head.a_dev;
335 	struct uio *uio = ap->a_uio;
336 	u_char *cp = 0;
337 	int cc = 0;
338 	u_char locbuf[BUFSIZ];
339 	int cnt = 0;
340 	int error = 0;
341 	struct tty *tp1, *tp;
342 	struct softpart *ourpart, *otherpart;
343 
344 	tp1 = dev->si_tty;
345 	/*
346 	 * Get the other tty struct.
347 	 * basically we are writing into the INPUT side of the other device.
348 	 */
349 	GETPARTS(tp1, ourpart, otherpart);
350 	tp = &otherpart->nm_tty;
351 
352 again:
353 	if ((tp->t_state & TS_ISOPEN) == 0)
354 		return (EIO);
355 	while (uio->uio_resid > 0 || cc > 0) {
356 		/*
357 		 * Fill up the buffer if it's empty
358 		 */
359 		if (cc == 0) {
360 			cc = min(uio->uio_resid, BUFSIZ);
361 			cp = locbuf;
362 			error = uiomove((caddr_t)cp, cc, uio);
363 			if (error)
364 				return (error);
365 			/* check again for safety */
366 			if ((tp->t_state & TS_ISOPEN) == 0) {
367 				/* adjust for data copied in but not written */
368 				uio->uio_resid += cc;
369 				return (EIO);
370 			}
371 		}
372 		while (cc > 0) {
373 			if (((tp->t_rawq.c_cc + tp->t_canq.c_cc) >= (TTYHOG-2))
374 			&& ((tp->t_canq.c_cc > 0) || !(tp->t_iflag&ICANON))) {
375 				/*
376 	 			 * Come here to wait for space in outq,
377 				 * or space in rawq, or an empty canq.
378 	 			 */
379 				wakeup(TSA_HUP_OR_INPUT(tp));
380 				if ((tp->t_state & TS_CONNECTED) == 0) {
381 					/*
382 					 * Data piled up because not connected.
383 					 * Adjust for data copied in but
384 					 * not written.
385 					 */
386 					uio->uio_resid += cc;
387 					return (EIO);
388 				}
389 				if (ap->a_ioflag & IO_NDELAY) {
390 					/*
391 				         * Don't wait if asked not to.
392 					 * Adjust for data copied in but
393 					 * not written.
394 					 */
395 					uio->uio_resid += cc;
396 					if (cnt == 0)
397 						return (EWOULDBLOCK);
398 					return (0);
399 				}
400 				error = tsleep(TSA_PTC_WRITE(tp),
401 						PCATCH, "nmdout", 0);
402 				if (error) {
403 					/*
404 					 * Tsleep returned (signal?).
405 					 * Go find out what the user wants.
406 					 * adjust for data copied in but
407 					 * not written
408 					 */
409 					uio->uio_resid += cc;
410 					return (error);
411 				}
412 				goto again;
413 			}
414 			(*linesw[tp->t_line].l_rint)(*cp++, tp);
415 			cnt++;
416 			cc--;
417 		}
418 		cc = 0;
419 	}
420 	return (0);
421 }
422 
423 /*
424  * Start output on pseudo-tty.
425  * Wake up process selecting or sleeping for input from controlling tty.
426  */
427 static void
428 nmdmstart(struct tty *tp)
429 {
430 	struct nm_softc *pti = tp->t_dev->si_drv1;
431 
432 	if (tp->t_state & TS_TTSTOP)
433 		return;
434 	pti->pt_flags &= ~PF_STOPPED;
435 	wakeup_other(tp, FREAD);
436 }
437 
438 /* Wakes up the OTHER tty;*/
439 static void
440 wakeup_other(struct tty *tp, int flag)
441 {
442 	struct softpart *ourpart, *otherpart;
443 
444 	GETPARTS(tp, ourpart, otherpart);
445 	if (flag & FREAD) {
446 		selwakeup(&otherpart->nm_tty.t_rsel);
447 		wakeup(TSA_PTC_READ((&otherpart->nm_tty)));
448 	}
449 	if (flag & FWRITE) {
450 		selwakeup(&otherpart->nm_tty.t_wsel);
451 		wakeup(TSA_PTC_WRITE((&otherpart->nm_tty)));
452 	}
453 }
454 
455 static	void
456 nmdmstop(struct tty *tp, int flush)
457 {
458 	struct nm_softc *pti = tp->t_dev->si_drv1;
459 	int flag;
460 
461 	/* note: FLUSHREAD and FLUSHWRITE already ok */
462 	if (flush == 0) {
463 		flush = TIOCPKT_STOP;
464 		pti->pt_flags |= PF_STOPPED;
465 	} else
466 		pti->pt_flags &= ~PF_STOPPED;
467 	/* change of perspective */
468 	flag = 0;
469 	if (flush & FREAD)
470 		flag |= FWRITE;
471 	if (flush & FWRITE)
472 		flag |= FREAD;
473 	wakeup_other(tp, flag);
474 }
475 
476 /*ARGSUSED*/
477 static	int
478 nmdmioctl(struct dev_ioctl_args *ap)
479 {
480 	cdev_t dev = ap->a_head.a_dev;
481 	struct tty *tp = dev->si_tty;
482 	struct nm_softc *pti = dev->si_drv1;
483 	int error;
484 	struct tty *tp2;
485 	struct softpart *ourpart, *otherpart;
486 
487 	crit_enter();
488 	GETPARTS(tp, ourpart, otherpart);
489 	tp2 = &otherpart->nm_tty;
490 
491 	error = (*linesw[tp->t_line].l_ioctl)(tp, ap->a_cmd, ap->a_data,
492 					      ap->a_fflag, ap->a_cred);
493 	if (error == ENOIOCTL)
494 		 error = ttioctl(tp, ap->a_cmd, ap->a_data, ap->a_fflag);
495 	if (error == ENOIOCTL) {
496 		switch (ap->a_cmd) {
497 		case TIOCSBRK:
498 			otherpart->gotbreak = 1;
499 			break;
500 		case TIOCCBRK:
501 			break;
502 		case TIOCSDTR:
503 			ourpart->modemsignals |= TIOCM_DTR;
504 			break;
505 		case TIOCCDTR:
506 			ourpart->modemsignals &= TIOCM_DTR;
507 			break;
508 		case TIOCMSET:
509 			ourpart->modemsignals = *(int *)ap->a_data;
510 			otherpart->modemsignals = *(int *)ap->a_data;
511 			break;
512 		case TIOCMBIS:
513 			ourpart->modemsignals |= *(int *)ap->a_data;
514 			break;
515 		case TIOCMBIC:
516 			ourpart->modemsignals &= ~(*(int *)ap->a_data);
517 			otherpart->modemsignals &= ~(*(int *)ap->a_data);
518 			break;
519 		case TIOCMGET:
520 			*(int *)ap->a_data = ourpart->modemsignals;
521 			break;
522 		case TIOCMSDTRWAIT:
523 			break;
524 		case TIOCMGDTRWAIT:
525 			*(int *)ap->a_data = 0;
526 			break;
527 		case TIOCTIMESTAMP:
528 		case TIOCDCDTIMESTAMP:
529 		default:
530 			crit_exit();
531 			error = ENOTTY;
532 			return (error);
533 		}
534 		error = 0;
535 		nmdm_crossover(pti, ourpart, otherpart);
536 	}
537 	crit_exit();
538 	return (error);
539 }
540 
541 static void
542 nmdm_crossover(struct nm_softc *pti,
543 		struct softpart *ourpart,
544 		struct softpart *otherpart)
545 {
546 	otherpart->modemsignals &= ~(TIOCM_CTS|TIOCM_CAR);
547 	if (ourpart->modemsignals & TIOCM_RTS)
548 		otherpart->modemsignals |= TIOCM_CTS;
549 	if (ourpart->modemsignals & TIOCM_DTR)
550 		otherpart->modemsignals |= TIOCM_CAR;
551 }
552 
553 
554 
555 static void nmdm_drvinit (void *unused);
556 
557 static void
558 nmdm_drvinit(void *unused)
559 {
560 	/* XXX: Gross hack for DEVFS */
561 	nmdminit(0);
562 }
563 
564 SYSINIT(nmdmdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,nmdm_drvinit,NULL)
565