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: head/sys/dev/nmdm/nmdm.c 111815 2003-03-03 12:15:54Z phk $
34 */
35
36/*
37 * Pseudo-nulmodem driver
38 * Mighty handy for use with serial console in Vmware
39 */
40
41#include "opt_compat.h"
42#include <sys/param.h>
43#include <sys/systm.h>
44#if defined(COMPAT_43) || defined(COMPAT_SUNOS)
45#include <sys/ioctl_compat.h>
46#endif
47#include <sys/proc.h>
48#include <sys/tty.h>
49#include <sys/conf.h>
50#include <sys/fcntl.h>
51#include <sys/poll.h>
52#include <sys/kernel.h>
53#include <sys/vnode.h>
54#include <sys/signalvar.h>
55#include <sys/malloc.h>
56
57MALLOC_DEFINE(M_NLMDM, "nullmodem", "nullmodem data structures");
58
59static void nmdmstart(struct tty *tp);
60static void nmdmstop(struct tty *tp, int rw);
61static void wakeup_other(struct tty *tp, int flag);
62static void nmdminit(int);
63static int nmdmshutdown(void);
64
65static d_open_t nmdmopen;
66static d_close_t nmdmclose;
67static d_read_t nmdmread;
68static d_write_t nmdmwrite;
69static d_ioctl_t nmdmioctl;
70
71#define CDEV_MAJOR 18
72static struct cdevsw nmdm_cdevsw = {
73 .d_open = nmdmopen,
74 .d_close = nmdmclose,
75 .d_read = nmdmread,
76 .d_write = nmdmwrite,
77 .d_ioctl = nmdmioctl,
78 .d_poll = ttypoll,
79 .d_name = "pts",
80 .d_maj = CDEV_MAJOR,
81 .d_flags = D_TTY,
82};
83
84#define BUFSIZ 100 /* Chunk size iomoved to/from user */
85#define NMDM_MAX_NUM 128 /* Artificially limit # devices. */
86#define PF_STOPPED 0x10 /* user told stopped */
87
88struct softpart {
89 struct tty nm_tty;
90 dev_t dev;
91 int modemsignals; /* bits defined in sys/ttycom.h */
92 int gotbreak;
93};
94
95struct nm_softc {
96 int pt_flags;
97 struct softpart part1, part2;
98 struct prison *pt_prison;
99};
100
101static void
102nmdm_crossover(struct nm_softc *pti,
103 struct softpart *ourpart,
104 struct softpart *otherpart);
105
106#define GETPARTS(tp, ourpart, otherpart) \
107do { \
108 struct nm_softc *pti = tp->t_dev->si_drv1; \
109 if (tp == &pti->part1.nm_tty) { \
110 ourpart = &pti->part1; \
111 otherpart = &pti->part2; \
112 } else { \
113 ourpart = &pti->part2; \
114 otherpart = &pti->part1; \
115 } \
116} while (0)
117
118/*
119 * This function creates and initializes a pair of ttys.
120 */
121static void
122nmdminit(n)
123 int n;
124{
125 dev_t dev1, dev2;
126 struct nm_softc *pt;
127
128 /* For now we only map the lower 8 bits of the minor */
129 if (n & ~0xff)
130 return;
131
132 pt = malloc(sizeof(*pt), M_NLMDM, M_WAITOK);
133 bzero(pt, sizeof(*pt));
134 pt->part1.dev = dev1 = make_dev(&nmdm_cdevsw, n+n,
135 0, 0, 0666, "nmdm%dA", n);
136 pt->part2.dev = dev2 = make_dev(&nmdm_cdevsw, n+n+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/*
153 * Device opened from userland
154 */
155static int
156nmdmopen(dev_t dev, int flag, int devtype, struct thread *td)
157{
158 register struct tty *tp, *tp2;
159 int error;
160 int minr;
161 dev_t nextdev;
162 struct nm_softc *pti;
163 int is_b;
164 int pair;
165 struct softpart *ourpart, *otherpart;
166
167 /*
168 * XXX: Gross hack for DEVFS:
169 * If we openned this device, ensure we have the
170 * next one too, so people can open it.
171 */
172 minr = dev2unit(dev);
173 pair = minr >> 1;
174 is_b = minr & 1;
175
176 if (pair < (NMDM_MAX_NUM - 1)) {
177 nextdev = makedev(major(dev), minr + 2);
178 if (!nextdev->si_drv1) {
179 nmdminit(pair + 1);
180 }
181 } else { /* Limit ourselves to 128 of them for now */
182 if (pair > (NMDM_MAX_NUM - 1))
183 return (ENXIO);
184 }
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
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(td)) {
209 return (EBUSY);
210 } else if (pti->pt_prison != td->td_ucred->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), 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/*
260 * Device closed again
261 */
262static int
263nmdmclose(dev_t dev, int flag, int mode, struct thread *td)
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/*
300 * handle read(2) request from userland
301 */
302static int
303nmdmread(dev_t dev, struct uio *uio, 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 */
337static int
338nmdmwrite(dev_t dev, struct uio *uio, int flag)
339{
340 register u_char *cp = 0;
341 register 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
356again:
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 TTOPRI | 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 */
431static void
432nmdmstart(struct tty *tp)
433{
434 register struct nm_softc *pti = tp->t_dev->si_drv1;
435
436 if (tp->t_state & TS_TTSTOP)
437 return;
438 pti->pt_flags &= ~PF_STOPPED;
439 wakeup_other(tp, FREAD);
440}
441
442/* Wakes up the OTHER tty;*/
443static void
444wakeup_other(struct tty *tp, int flag)
445{
446 struct softpart *ourpart, *otherpart;
447
448 GETPARTS(tp, ourpart, otherpart);
449 if (flag & FREAD) {
450 selwakeup(&otherpart->nm_tty.t_rsel);
451 wakeup(TSA_PTC_READ((&otherpart->nm_tty)));
452 }
453 if (flag & FWRITE) {
454 selwakeup(&otherpart->nm_tty.t_wsel);
455 wakeup(TSA_PTC_WRITE((&otherpart->nm_tty)));
456 }
457}
458
459/*
460 * stopped output on tty, called when device is closed
461 */
462static void
463nmdmstop(register struct tty *tp, int flush)
464{
465 struct nm_softc *pti = tp->t_dev->si_drv1;
466 int flag;
467
468 /* note: FLUSHREAD and FLUSHWRITE already ok */
469 if (flush == 0) {
470 flush = TIOCPKT_STOP;
471 pti->pt_flags |= PF_STOPPED;
472 } else
473 pti->pt_flags &= ~PF_STOPPED;
474 /* change of perspective */
475 flag = 0;
476 if (flush & FREAD)
477 flag |= FWRITE;
478 if (flush & FWRITE)
479 flag |= FREAD;
480 wakeup_other(tp, flag);
481}
482
483/*
484 * handle ioctl(2) request from userland
485 */
486static int
487nmdmioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct thread *td)
488{
489 register struct tty *tp = dev->si_tty;
490 struct nm_softc *pti = dev->si_drv1;
491 int error, s;
492 register 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 /* FALLTHROUGH */
536 case TIOCDCDTIMESTAMP:
537 default:
538 splx(s);
539 error = ENOTTY;
540 return (error);
541 }
542 error = 0;
543 nmdm_crossover(pti, ourpart, otherpart);
544 }
545 splx(s);
546 return (error);
547}
548
549static void
550nmdm_crossover(struct nm_softc *pti, 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 * Module handling
562 */
563static int
564nmdm_modevent(module_t mod, int type, void *data)
565{
566 int error = 0;
567
568 switch(type) {
569 case MOD_LOAD: /* start with 4 of them */
570 nmdminit(0);
571 nmdminit(1);
572 nmdminit(2);
573 nmdminit(3);
574 break;
575
576 case MOD_SHUTDOWN:
577 /* FALLTHROUGH */
578 case MOD_UNLOAD:
579 nmdmshutdown();
580 break;
581 default:
582 error = EOPNOTSUPP;
583 }
584 return (error);
585}
586
587/*
588 * Handle teardown of device
589 */
590static int
591nmdmshutdown(void)
592{
593 int i;
594 dev_t nextdev1;
595 dev_t nextdev2;
596 void * ptr1;
597
598 for(i = 0;( i < NMDM_MAX_NUM) ;i++) {
599 nextdev1 = makedev(CDEV_MAJOR, (i+i) );
600 nextdev2 = makedev(CDEV_MAJOR, (i+i) + 1);
601 ptr1 = nextdev1->si_drv1;
602 if (ptr1) {
603 revoke_and_destroy_dev(nextdev1);
604 revoke_and_destroy_dev(nextdev2);
605 free(ptr1, M_NLMDM);
606 } else {
607 freedev(nextdev1);
608 freedev(nextdev2);
609 }
610 }
611 return(0);
612}
613
614DEV_MODULE(nmdm, nmdm_modevent, NULL);