nmdm.c revision 111815 
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);
615