nmdm.c revision 130640 
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 130640 2004-06-17 17:16:53Z 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/vnode.h>
52#include <sys/signalvar.h>
53#include <sys/malloc.h>
54#include <sys/taskqueue.h>
55
56MALLOC_DEFINE(M_NLMDM, "nullmodem", "nullmodem data structures");
57
58static void 	nmdmstart(struct tty *tp);
59static void 	nmdmstop(struct tty *tp, int rw);
60static void 	nmdminit(struct cdev *dev);
61
62static d_open_t		nmdmopen;
63static d_close_t	nmdmclose;
64
65static struct cdevsw nmdm_cdevsw = {
66	.d_version =	D_VERSION,
67	.d_open =	nmdmopen,
68	.d_close =	nmdmclose,
69	.d_name =	"nmdn",
70	.d_flags =	D_TTY | D_PSEUDO | D_NEEDGIANT,
71};
72
73#define BUFSIZ 		100		/* Chunk size iomoved to/from user */
74#define NMDM_MAX_NUM	128		/* Artificially limit # devices. */
75#define	PF_STOPPED	0x10		/* user told stopped */
76#define BFLAG		CLONE_FLAG0
77
78struct softpart {
79	struct tty	*nm_tty;
80	struct cdev *dev;
81	int	dcd;
82	struct task		pt_task;
83	struct softpart		*other;
84};
85
86struct	nm_softc {
87	TAILQ_ENTRY(nm_softc)	pt_list;
88	int			pt_flags;
89	struct softpart 	part1, part2;
90	struct	prison 		*pt_prison;
91};
92
93static struct clonedevs *nmdmclones;
94static TAILQ_HEAD(,nm_softc) nmdmhead = TAILQ_HEAD_INITIALIZER(nmdmhead);
95
96static void
97nmdm_clone(void *arg, char *name, int nameen, struct cdev **dev)
98{
99	int i, unit;
100	char *p;
101	struct cdev *d1, *d2;
102
103	if (*dev != NULL)
104		return;
105	if (strcmp(name, "nmdm") == 0) {
106		p = NULL;
107		unit = -1;
108	} else {
109		i = dev_stdclone(name, &p, "nmdm", &unit);
110		if (i == 0)
111			return;
112		if (p[0] != '\0' && p[0] != 'A' && p[0] != 'B')
113			return;
114		else if (p[0] != '\0' && p[1] != '\0')
115			return;
116	}
117	i = clone_create(&nmdmclones, &nmdm_cdevsw, &unit, &d1, 0);
118	if (i) {
119		d1 = make_dev(&nmdm_cdevsw, unit2minor(unit),
120		     0, 0, 0666, "nmdm%dA", unit);
121		if (d1 == NULL)
122			return;
123		d2 = make_dev(&nmdm_cdevsw, unit2minor(unit) | BFLAG,
124		     0, 0, 0666, "nmdm%dB", unit);
125		if (d2 == NULL) {
126			destroy_dev(d1);
127			return;
128		}
129		d2->si_drv2 = d1;
130		d1->si_drv2 = d2;
131		dev_depends(d1, d2);
132		dev_depends(d2, d1);
133		d1->si_flags |= SI_CHEAPCLONE;
134		d2->si_flags |= SI_CHEAPCLONE;
135	}
136	if (p != NULL && p[0] == 'B')
137		*dev = d1->si_drv2;
138	else
139		*dev = d1;
140}
141
142static void
143nmdm_task_tty(void *arg, int pending __unused)
144{
145	struct tty *tp, *otp;
146	struct softpart *sp;
147	int c;
148
149	tp = arg;
150	sp = tp->t_sc;
151	otp = sp->other->nm_tty;
152	KASSERT(otp != NULL, ("NULL otp in nmdmstart"));
153	KASSERT(otp != tp, ("NULL otp == tp nmdmstart"));
154	if (sp->other->dcd) {
155		if (!(tp->t_state & TS_ISOPEN)) {
156			sp->other->dcd = 0;
157			(void)ttyld_modem(otp, 0);
158		}
159	} else {
160		if (tp->t_state & TS_ISOPEN) {
161			sp->other->dcd = 1;
162			(void)ttyld_modem(otp, 1);
163		}
164	}
165	if (tp->t_state & TS_TTSTOP)
166		return;
167	while (tp->t_outq.c_cc != 0) {
168		if (otp->t_state & TS_TBLOCK)
169			return;
170		c = getc(&tp->t_outq);
171		if (otp->t_state & TS_ISOPEN)
172			ttyld_rint(otp, c);
173	}
174	if (tp->t_outq.c_cc == 0)
175		ttwwakeup(tp);
176}
177
178/*
179 * This function creates and initializes a pair of ttys.
180 */
181static void
182nmdminit(struct cdev *dev1)
183{
184	struct cdev *dev2;
185	struct nm_softc *pt;
186
187	dev2 = dev1->si_drv2;
188
189	dev1->si_flags &= ~SI_CHEAPCLONE;
190	dev2->si_flags &= ~SI_CHEAPCLONE;
191
192	pt = malloc(sizeof(*pt), M_NLMDM, M_WAITOK | M_ZERO);
193	TAILQ_INSERT_TAIL(&nmdmhead, pt, pt_list);
194
195	dev1->si_drv1 = dev2->si_drv1 = pt;
196
197	pt->part1.dev = dev1;
198	pt->part2.dev = dev2;
199
200	pt->part1.nm_tty = ttymalloc(pt->part1.nm_tty);
201	pt->part1.nm_tty->t_oproc = nmdmstart;
202	pt->part1.nm_tty->t_stop = nmdmstop;
203	pt->part1.nm_tty->t_dev = dev1;
204	pt->part1.nm_tty->t_sc = &pt->part1;
205	TASK_INIT(&pt->part1.pt_task, 0, nmdm_task_tty, pt->part1.nm_tty);
206
207	pt->part2.nm_tty = ttymalloc(pt->part2.nm_tty);
208	pt->part2.nm_tty->t_oproc = nmdmstart;
209	pt->part2.nm_tty->t_stop = nmdmstop;
210	pt->part2.nm_tty->t_dev = dev2;
211	pt->part2.nm_tty->t_sc = &pt->part2;
212	TASK_INIT(&pt->part2.pt_task, 0, nmdm_task_tty, pt->part2.nm_tty);
213
214	pt->part1.other = &pt->part2;
215	pt->part2.other = &pt->part1;
216
217	dev1->si_tty = pt->part1.nm_tty;
218	dev1->si_drv1 = pt;
219
220	dev2->si_tty = pt->part2.nm_tty;
221	dev2->si_drv1 = pt;
222}
223
224/*
225 * Device opened from userland
226 */
227static	int
228nmdmopen(struct cdev *dev, int flag, int devtype, struct thread *td)
229{
230	struct tty *tp, *tp2;
231	int error;
232	struct nm_softc *pti;
233	struct softpart *sp;
234
235	if (dev->si_drv1 == NULL)
236		nmdminit(dev);
237	pti = dev->si_drv1;
238	if (pti->pt_prison != td->td_ucred->cr_prison)
239		return (EBUSY);
240
241	tp = dev->si_tty;
242	sp = tp->t_sc;
243	tp2 = sp->other->nm_tty;
244
245	if ((tp->t_state & TS_ISOPEN) == 0) {
246		ttychars(tp);		/* Set up default chars */
247		tp->t_iflag = TTYDEF_IFLAG;
248		tp->t_oflag = TTYDEF_OFLAG;
249		tp->t_lflag = TTYDEF_LFLAG;
250		tp->t_lflag = 0;
251		tp->t_cflag = TTYDEF_CFLAG;
252		tp->t_ispeed = tp->t_ospeed = TTYDEF_SPEED;
253		ttsetwater(tp); /* XXX ? */
254	} else if (tp->t_state & TS_XCLUDE && suser(td)) {
255		return (EBUSY);
256	}
257
258	error = ttyld_open(tp, dev);
259	return (error);
260}
261
262static int
263nmdmclose(struct cdev *dev, int flag, int mode, struct thread *td)
264{
265
266	return (ttyclose(dev->si_tty));
267}
268
269static void
270nmdmstart(struct tty *tp)
271{
272	struct softpart *pt;
273
274	pt = tp->t_sc;
275	taskqueue_enqueue(taskqueue_swi_giant, &pt->pt_task);
276}
277
278static void
279nmdmstop(struct tty *tp, int flush)
280{
281	struct softpart *pt;
282
283	pt = tp->t_sc;
284	taskqueue_enqueue(taskqueue_swi_giant, &pt->pt_task);
285}
286
287/*
288 * Module handling
289 */
290static int
291nmdm_modevent(module_t mod, int type, void *data)
292{
293	static eventhandler_tag tag;
294	struct nm_softc *pt, *tpt;
295        int error = 0;
296
297        switch(type) {
298        case MOD_LOAD:
299		clone_setup(&nmdmclones);
300		tag = EVENTHANDLER_REGISTER(dev_clone, nmdm_clone, 0, 1000);
301		if (tag == NULL)
302			return (ENOMEM);
303		break;
304
305	case MOD_SHUTDOWN:
306		/* FALLTHROUGH */
307	case MOD_UNLOAD:
308		EVENTHANDLER_DEREGISTER(dev_clone, tag);
309		TAILQ_FOREACH_SAFE(pt, &nmdmhead, pt_list, tpt) {
310			destroy_dev(pt->part1.dev);
311			TAILQ_REMOVE(&nmdmhead, pt, pt_list);
312			free(pt, M_NLMDM);
313		}
314		clone_cleanup(&nmdmclones);
315		break;
316	default:
317		error = EOPNOTSUPP;
318	}
319	return (error);
320}
321
322DEV_MODULE(nmdm, nmdm_modevent, NULL);
323