nmdm.c revision 132226 
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 * 4. Neither the name of the University nor the names of its contributors
14 *    may be used to endorse or promote products derived from this software
15 *    without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 */
30
31#include <sys/cdefs.h>
32__FBSDID("$FreeBSD: head/sys/dev/nmdm/nmdm.c 132226 2004-07-15 20:47:41Z phk $");
33
34/*
35 * Pseudo-nulmodem driver
36 * Mighty handy for use with serial console in Vmware
37 */
38
39#include "opt_compat.h"
40#include "opt_tty.h"
41
42#include <sys/param.h>
43#include <sys/systm.h>
44#include <sys/proc.h>
45#include <sys/tty.h>
46#include <sys/conf.h>
47#include <sys/fcntl.h>
48#include <sys/poll.h>
49#include <sys/kernel.h>
50#include <sys/module.h>
51#include <sys/serial.h>
52#include <sys/vnode.h>
53#include <sys/signalvar.h>
54#include <sys/malloc.h>
55#include <sys/taskqueue.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 	nmdminit(struct cdev *dev);
62static t_modem_t	nmdmmodem;
63
64static d_open_t		nmdmopen;
65static d_close_t	nmdmclose;
66
67static struct cdevsw nmdm_cdevsw = {
68	.d_version =	D_VERSION,
69	.d_open =	nmdmopen,
70	.d_close =	nmdmclose,
71	.d_name =	"nmdn",
72	.d_flags =	D_TTY | D_PSEUDO | D_NEEDGIANT,
73};
74
75#define BUFSIZ 		100		/* Chunk size iomoved to/from user */
76#define NMDM_MAX_NUM	128		/* Artificially limit # devices. */
77#define	PF_STOPPED	0x10		/* user told stopped */
78#define BFLAG		CLONE_FLAG0
79
80struct softpart {
81	struct tty		*nm_tty;
82	struct cdev 		*dev;
83	int			nm_dcd;
84	struct task		pt_task;
85	struct softpart		*other;
86};
87
88struct	nm_softc {
89	TAILQ_ENTRY(nm_softc)	pt_list;
90	int			pt_flags;
91	struct softpart 	part1, part2;
92	struct	prison 		*pt_prison;
93};
94
95static struct clonedevs *nmdmclones;
96static TAILQ_HEAD(,nm_softc) nmdmhead = TAILQ_HEAD_INITIALIZER(nmdmhead);
97
98static void
99nmdm_clone(void *arg, char *name, int nameen, struct cdev **dev)
100{
101	int i, unit;
102	char *p;
103	struct cdev *d1, *d2;
104
105	if (*dev != NULL)
106		return;
107	if (strcmp(name, "nmdm") == 0) {
108		p = NULL;
109		unit = -1;
110	} else {
111		i = dev_stdclone(name, &p, "nmdm", &unit);
112		if (i == 0)
113			return;
114		if (p[0] != '\0' && p[0] != 'A' && p[0] != 'B')
115			return;
116		else if (p[0] != '\0' && p[1] != '\0')
117			return;
118	}
119	i = clone_create(&nmdmclones, &nmdm_cdevsw, &unit, &d1, 0);
120	if (i) {
121		d1 = make_dev(&nmdm_cdevsw, unit2minor(unit),
122		     0, 0, 0666, "nmdm%dA", unit);
123		if (d1 == NULL)
124			return;
125		d2 = make_dev(&nmdm_cdevsw, unit2minor(unit) | BFLAG,
126		     0, 0, 0666, "nmdm%dB", unit);
127		if (d2 == NULL) {
128			destroy_dev(d1);
129			return;
130		}
131		d2->si_drv2 = d1;
132		d1->si_drv2 = d2;
133		dev_depends(d1, d2);
134		dev_depends(d2, d1);
135		d1->si_flags |= SI_CHEAPCLONE;
136		d2->si_flags |= SI_CHEAPCLONE;
137	}
138	if (p != NULL && p[0] == 'B')
139		*dev = d1->si_drv2;
140	else
141		*dev = d1;
142}
143
144static void
145nmdm_task_tty(void *arg, int pending __unused)
146{
147	struct tty *tp, *otp;
148	struct softpart *sp;
149	int c;
150
151	tp = arg;
152	sp = tp->t_sc;
153	otp = sp->other->nm_tty;
154	KASSERT(otp != NULL, ("NULL otp in nmdmstart"));
155	KASSERT(otp != tp, ("NULL otp == tp nmdmstart"));
156	if (sp->other->nm_dcd) {
157		if (!(tp->t_state & TS_ISOPEN)) {
158			sp->other->nm_dcd = 0;
159			(void)ttyld_modem(otp, 0);
160		}
161	} else {
162		if (tp->t_state & TS_ISOPEN) {
163			sp->other->nm_dcd = 1;
164			(void)ttyld_modem(otp, 1);
165		}
166	}
167	if (tp->t_state & TS_TTSTOP)
168		return;
169	while (tp->t_outq.c_cc != 0) {
170		if (otp->t_state & TS_TBLOCK)
171			return;
172		c = getc(&tp->t_outq);
173		if (otp->t_state & TS_ISOPEN)
174			ttyld_rint(otp, c);
175	}
176	if (tp->t_outq.c_cc == 0)
177		ttwwakeup(tp);
178}
179
180/*
181 * This function creates and initializes a pair of ttys.
182 */
183static void
184nmdminit(struct cdev *dev1)
185{
186	struct cdev *dev2;
187	struct nm_softc *pt;
188
189	dev2 = dev1->si_drv2;
190
191	dev1->si_flags &= ~SI_CHEAPCLONE;
192	dev2->si_flags &= ~SI_CHEAPCLONE;
193
194	pt = malloc(sizeof(*pt), M_NLMDM, M_WAITOK | M_ZERO);
195	TAILQ_INSERT_TAIL(&nmdmhead, pt, pt_list);
196
197	dev1->si_drv1 = dev2->si_drv1 = pt;
198
199	pt->part1.dev = dev1;
200	pt->part2.dev = dev2;
201
202	pt->part1.nm_tty = ttymalloc(pt->part1.nm_tty);
203	pt->part1.nm_tty->t_oproc = nmdmstart;
204	pt->part1.nm_tty->t_stop = nmdmstop;
205	pt->part1.nm_tty->t_modem = nmdmmodem;
206	pt->part1.nm_tty->t_dev = dev1;
207	pt->part1.nm_tty->t_sc = &pt->part1;
208	TASK_INIT(&pt->part1.pt_task, 0, nmdm_task_tty, pt->part1.nm_tty);
209
210	pt->part2.nm_tty = ttymalloc(pt->part2.nm_tty);
211	pt->part2.nm_tty->t_oproc = nmdmstart;
212	pt->part2.nm_tty->t_stop = nmdmstop;
213	pt->part2.nm_tty->t_modem = nmdmmodem;
214	pt->part2.nm_tty->t_dev = dev2;
215	pt->part2.nm_tty->t_sc = &pt->part2;
216	TASK_INIT(&pt->part2.pt_task, 0, nmdm_task_tty, pt->part2.nm_tty);
217
218	pt->part1.other = &pt->part2;
219	pt->part2.other = &pt->part1;
220
221	dev1->si_tty = pt->part1.nm_tty;
222	dev1->si_drv1 = pt;
223
224	dev2->si_tty = pt->part2.nm_tty;
225	dev2->si_drv1 = pt;
226}
227
228/*
229 * Device opened from userland
230 */
231static	int
232nmdmopen(struct cdev *dev, int flag, int devtype, struct thread *td)
233{
234	struct tty *tp, *tp2;
235	int error;
236	struct nm_softc *pti;
237	struct softpart *sp;
238
239	if (dev->si_drv1 == NULL)
240		nmdminit(dev);
241	pti = dev->si_drv1;
242	if (pti->pt_prison != td->td_ucred->cr_prison)
243		return (EBUSY);
244
245	tp = dev->si_tty;
246	sp = tp->t_sc;
247	tp2 = sp->other->nm_tty;
248
249	if ((tp->t_state & TS_ISOPEN) == 0) {
250		ttychars(tp);		/* Set up default chars */
251		tp->t_iflag = TTYDEF_IFLAG;
252		tp->t_oflag = TTYDEF_OFLAG;
253		tp->t_lflag = TTYDEF_LFLAG;
254		tp->t_lflag = 0;
255		tp->t_cflag = TTYDEF_CFLAG;
256		tp->t_ispeed = tp->t_ospeed = TTYDEF_SPEED;
257		ttsetwater(tp); /* XXX ? */
258	} else if (tp->t_state & TS_XCLUDE && suser(td)) {
259		return (EBUSY);
260	}
261
262	error = ttyld_open(tp, dev);
263	return (error);
264}
265
266static int
267nmdmmodem(struct tty *tp, int sigon, int sigoff)
268{
269	struct softpart *sp;
270	int i;
271
272	sp = tp->t_sc;
273	if (sigon || sigoff) {
274		if (sigon & SER_DTR) {
275			sp->other->nm_dcd = 1;
276			ttyld_modem(sp->other->nm_tty, sp->other->nm_dcd);
277		}
278		if (sigoff & SER_DTR) {
279			sp->other->nm_dcd = 0;
280			ttyld_modem(sp->other->nm_tty, sp->other->nm_dcd);
281		}
282		return (0);
283	} else {
284		i = 0;
285		if (sp->nm_dcd)
286			i |= SER_DCD;
287		if (sp->other->nm_dcd)
288			i |= SER_DTR;
289		return (i);
290	}
291}
292
293static int
294nmdmclose(struct cdev *dev, int flag, int mode, struct thread *td)
295{
296
297	return (tty_close(dev->si_tty));
298}
299
300static void
301nmdmstart(struct tty *tp)
302{
303	struct softpart *pt;
304
305	pt = tp->t_sc;
306	taskqueue_enqueue(taskqueue_swi_giant, &pt->pt_task);
307}
308
309static void
310nmdmstop(struct tty *tp, int flush)
311{
312	struct softpart *pt;
313
314	pt = tp->t_sc;
315	taskqueue_enqueue(taskqueue_swi_giant, &pt->pt_task);
316}
317
318/*
319 * Module handling
320 */
321static int
322nmdm_modevent(module_t mod, int type, void *data)
323{
324	static eventhandler_tag tag;
325	struct nm_softc *pt, *tpt;
326        int error = 0;
327
328        switch(type) {
329        case MOD_LOAD:
330		clone_setup(&nmdmclones);
331		tag = EVENTHANDLER_REGISTER(dev_clone, nmdm_clone, 0, 1000);
332		if (tag == NULL)
333			return (ENOMEM);
334		break;
335
336	case MOD_SHUTDOWN:
337		/* FALLTHROUGH */
338	case MOD_UNLOAD:
339		EVENTHANDLER_DEREGISTER(dev_clone, tag);
340		TAILQ_FOREACH_SAFE(pt, &nmdmhead, pt_list, tpt) {
341			destroy_dev(pt->part1.dev);
342			TAILQ_REMOVE(&nmdmhead, pt, pt_list);
343			free(pt, M_NLMDM);
344		}
345		clone_cleanup(&nmdmclones);
346		break;
347	default:
348		error = EOPNOTSUPP;
349	}
350	return (error);
351}
352
353DEV_MODULE(nmdm, nmdm_modevent, NULL);
354