kern_conf.c revision 49535 
1/*-
2 * Parts Copyright (c) 1995 Terrence R. Lambert
3 * Copyright (c) 1995 Julian R. Elischer
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 * 3. All advertising materials mentioning features or use of this software
15 *    must display the following acknowledgement:
16 *      This product includes software developed by Terrence R. Lambert.
17 * 4. The name Terrence R. Lambert may not be used to endorse or promote
18 *    products derived from this software without specific prior written
19 *    permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY Julian R. Elischer ``AS IS'' AND ANY
22 * 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 TERRENCE R. LAMBERT 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 * $Id: kern_conf.c,v 1.54 1999/08/08 00:34:00 grog Exp $
34 */
35
36#include <sys/param.h>
37#include <sys/kernel.h>
38#include <sys/systm.h>
39#include <sys/module.h>
40#include <sys/malloc.h>
41#include <sys/conf.h>
42#include <sys/vnode.h>
43#include <sys/queue.h>
44#include <machine/stdarg.h>
45
46#define cdevsw_ALLOCSTART	(NUMCDEVSW/2)
47
48struct cdevsw 	*cdevsw[NUMCDEVSW];
49
50static int	bmaj2cmaj[NUMCDEVSW];
51
52MALLOC_DEFINE(M_DEVT, "dev_t", "dev_t storage");
53
54#define DEVT_HASH 83
55#define DEVT_STASH 50
56
57static struct specinfo devt_stash[DEVT_STASH];
58
59static SLIST_HEAD(devt_hash_head, specinfo) dev_hash[DEVT_HASH];
60
61/*
62 * Routine to convert from character to block device number.
63 *
64 * A minimal stub routine can always return NODEV.
65 */
66dev_t
67chrtoblk(dev_t dev)
68{
69	struct cdevsw *cd;
70
71	if((cd = devsw(dev)) != NULL) {
72          if (cd->d_bmaj != -1)
73	    return(makebdev(cd->d_bmaj,minor(dev)));
74	}
75	return(NODEV);
76}
77
78struct cdevsw *
79devsw(dev_t dev)
80{
81        return(cdevsw[major(dev)]);
82}
83
84struct cdevsw *
85bdevsw(dev_t dev)
86{
87        return(cdevsw[major(dev)]);
88}
89
90/*
91 *  Add a cdevsw entry
92 */
93
94int
95cdevsw_add(struct cdevsw *newentry)
96{
97	int i;
98	static int setup;
99
100	if (!setup) {
101		for (i = 0; i < NUMCDEVSW; i++)
102			if (!bmaj2cmaj[i])
103				bmaj2cmaj[i] = 254;
104		setup++;
105	}
106
107	if (newentry->d_maj < 0 || newentry->d_maj >= NUMCDEVSW) {
108		printf("%s: ERROR: driver has bogus cdevsw->d_maj = %d\n",
109		    newentry->d_name, newentry->d_maj);
110		return EINVAL;
111	}
112
113	if (cdevsw[newentry->d_maj]) {
114		printf("WARNING: \"%s\" is usurping \"%s\"'s cdevsw[]\n",
115		    newentry->d_name, cdevsw[newentry->d_maj]->d_name);
116	}
117	cdevsw[newentry->d_maj] = newentry;
118
119	if (newentry->d_bmaj >= 0 && newentry->d_bmaj < NUMCDEVSW) {
120		if (bmaj2cmaj[newentry->d_bmaj] != 254) {
121			printf("WARNING: \"%s\" is usurping \"%s\"'s bmaj\n",
122			    newentry->d_name,
123			    cdevsw[bmaj2cmaj[newentry->d_bmaj]]->d_name);
124		}
125		bmaj2cmaj[newentry->d_bmaj] = newentry->d_maj;
126	}
127
128	return 0;
129}
130
131/*
132 *  Remove a cdevsw entry
133 */
134
135int
136cdevsw_remove(struct cdevsw *oldentry)
137{
138	if (oldentry->d_maj < 0 || oldentry->d_maj >= NUMCDEVSW) {
139		printf("%s: ERROR: driver has bogus cdevsw->d_maj = %d\n",
140		    oldentry->d_name, oldentry->d_maj);
141		return EINVAL;
142	}
143
144	cdevsw[oldentry->d_maj] = NULL;
145
146	if (oldentry->d_bmaj >= 0 && oldentry->d_bmaj < NUMCDEVSW)
147		bmaj2cmaj[oldentry->d_bmaj] = 254;
148
149	return 0;
150}
151
152int
153devsw_module_handler(module_t mod, int what, void* arg)
154{
155	struct devsw_module_data* data = (struct devsw_module_data*) arg;
156	int error = 0;
157
158	switch (what) {
159	case MOD_LOAD:
160		error = cdevsw_add(data->cdevsw);
161		if (!error && data->chainevh)
162			error = data->chainevh(mod, what, data->chainarg);
163		return error;
164
165	case MOD_UNLOAD:
166		if (data->chainevh) {
167			error = data->chainevh(mod, what, data->chainarg);
168			if (error)
169				return error;
170		}
171		cdevsw_remove(data->cdevsw);
172		return error;
173	}
174
175	if (data->chainevh)
176		return data->chainevh(mod, what, data->chainarg);
177	else
178		return 0;
179}
180
181/*
182 * dev_t and u_dev_t primitives
183 */
184
185int
186major(dev_t x)
187{
188	if (x == NODEV)
189		return NOUDEV;
190	return((x->si_udev >> 8) & 0xff);
191}
192
193int
194minor(dev_t x)
195{
196	if (x == NODEV)
197		return NOUDEV;
198	return(x->si_udev & 0xffff00ff);
199}
200
201dev_t
202makebdev(int x, int y)
203{
204	return (makedev(bmaj2cmaj[x], y));
205}
206
207dev_t
208makedev(int x, int y)
209{
210	struct specinfo *si;
211	udev_t	udev;
212	int hash;
213	static int stashed;
214
215	udev = (x << 8) | y;
216	hash = udev % DEVT_HASH;
217	SLIST_FOREACH(si, &dev_hash[hash], si_hash) {
218		if (si->si_udev == udev)
219			return (si);
220	}
221	if (stashed >= DEVT_STASH) {
222		MALLOC(si, struct specinfo *, sizeof(*si), M_DEVT,
223		    M_USE_RESERVE);
224	} else {
225		si = devt_stash + stashed++;
226	}
227	bzero(si, sizeof(*si));
228	si->si_udev = udev;
229	si->si_bsize_phys = DEV_BSIZE;
230	si->si_bsize_best = BLKDEV_IOSIZE;
231	si->si_bsize_max = MAXBSIZE;
232	if (y > 256)
233		sprintf(si->si_name, "#%d/0x%x", x, y);
234	else
235		sprintf(si->si_name, "#%d/%d", x, y);
236	SLIST_INSERT_HEAD(&dev_hash[hash], si, si_hash);
237        return (si);
238}
239
240udev_t
241dev2udev(dev_t x)
242{
243	if (x == NODEV)
244		return NOUDEV;
245	return (x->si_udev);
246}
247
248udev_t
249dev2budev(dev_t x)
250{
251	if (x == NODEV)
252		return NOUDEV;
253	else
254		return makeudev(devsw(x)->d_bmaj, minor(x));
255}
256
257dev_t
258udev2dev(udev_t x, int b)
259{
260	switch (b) {
261		case 0:
262			return makedev(umajor(x), uminor(x));
263		case 1:
264			return makebdev(umajor(x), uminor(x));
265		default:
266			Debugger("udev2dev(...,X)");
267			return NODEV;
268	}
269}
270
271int
272uminor(udev_t dev)
273{
274	return(dev & 0xffff00ff);
275}
276
277int
278umajor(udev_t dev)
279{
280	return((dev & 0xff00) >> 8);
281}
282
283udev_t
284makeudev(int x, int y)
285{
286        return ((x << 8) | y);
287}
288
289dev_t
290make_dev(struct cdevsw *devsw, int minor, uid_t uid, gid_t gid, int perms, char *fmt, ...)
291{
292	dev_t	dev;
293	va_list ap;
294	int i;
295
296	dev = makedev(devsw->d_maj, minor);
297	va_start(ap, fmt);
298	i = kvprintf(fmt, NULL, dev->si_name, 32, ap);
299	dev->si_name[i] = '\0';
300	va_end(ap);
301	dev->si_devsw = devsw;
302	return (dev);
303}
304
305