kern_conf.c revision 68063 
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 * $FreeBSD: head/sys/kern/kern_conf.c 68063 2000-10-31 10:58:14Z phk $
34 */
35
36#include <sys/param.h>
37#include <sys/kernel.h>
38#include <sys/sysctl.h>
39#include <sys/systm.h>
40#include <sys/module.h>
41#include <sys/malloc.h>
42#include <sys/conf.h>
43#include <sys/vnode.h>
44#include <sys/queue.h>
45#include <sys/ctype.h>
46#include <machine/stdarg.h>
47
48#define cdevsw_ALLOCSTART	(NUMCDEVSW/2)
49
50struct cdevsw 	*cdevsw[NUMCDEVSW];
51
52MALLOC_DEFINE(M_DEVT, "dev_t", "dev_t storage");
53
54/*
55 * This is the number of hash-buckets.  Experiements with 'real-life'
56 * udev_t's show that a prime halfway between two powers of two works
57 * best.
58 */
59#define DEVT_HASH 83
60
61/* The number of dev_t's we can create before malloc(9) kick in.  */
62#define DEVT_STASH 50
63
64static struct specinfo devt_stash[DEVT_STASH];
65
66static LIST_HEAD(, specinfo) dev_hash[DEVT_HASH];
67
68static LIST_HEAD(, specinfo) dev_free;
69
70devfs_create_t *devfs_create_hook;
71devfs_destroy_t *devfs_destroy_hook;
72int devfs_present;
73
74static int free_devt;
75SYSCTL_INT(_debug, OID_AUTO, free_devt, CTLFLAG_RW, &free_devt, 0, "");
76
77struct cdevsw *
78devsw(dev_t dev)
79{
80	if (dev->si_devsw)
81		return (dev->si_devsw);
82        return(cdevsw[major(dev)]);
83}
84
85/*
86 *  Add a cdevsw entry
87 */
88
89int
90cdevsw_add(struct cdevsw *newentry)
91{
92	int i;
93	static int setup;
94
95	if (newentry->d_maj < 0 || newentry->d_maj >= NUMCDEVSW) {
96		printf("%s: ERROR: driver has bogus cdevsw->d_maj = %d\n",
97		    newentry->d_name, newentry->d_maj);
98		return (EINVAL);
99	}
100
101	if (cdevsw[newentry->d_maj]) {
102		printf("WARNING: \"%s\" is usurping \"%s\"'s cdevsw[]\n",
103		    newentry->d_name, cdevsw[newentry->d_maj]->d_name);
104	}
105
106	cdevsw[newentry->d_maj] = newentry;
107
108	return (0);
109}
110
111/*
112 *  Remove a cdevsw entry
113 */
114
115int
116cdevsw_remove(struct cdevsw *oldentry)
117{
118	if (oldentry->d_maj < 0 || oldentry->d_maj >= NUMCDEVSW) {
119		printf("%s: ERROR: driver has bogus cdevsw->d_maj = %d\n",
120		    oldentry->d_name, oldentry->d_maj);
121		return EINVAL;
122	}
123
124	cdevsw[oldentry->d_maj] = NULL;
125
126	return 0;
127}
128
129/*
130 * dev_t and u_dev_t primitives
131 */
132
133int
134major(dev_t x)
135{
136	if (x == NODEV)
137		return NOUDEV;
138	return((x->si_udev >> 8) & 0xff);
139}
140
141int
142minor(dev_t x)
143{
144	if (x == NODEV)
145		return NOUDEV;
146	return(x->si_udev & 0xffff00ff);
147}
148
149int
150dev2unit(dev_t x)
151{
152	int i;
153
154	if (x == NODEV)
155		return NOUDEV;
156	i = minor(x);
157	return ((i & 0xff) | (i >> 8));
158}
159
160int
161unit2minor(int unit)
162{
163
164	return ((unit & 0xff) | ((unit << 8) & ~0xffff));
165}
166
167static dev_t
168allocdev(void)
169{
170	static int stashed;
171	struct specinfo *si;
172
173	if (stashed >= DEVT_STASH) {
174		MALLOC(si, struct specinfo *, sizeof(*si), M_DEVT,
175		    M_USE_RESERVE);
176		bzero(si, sizeof(*si));
177	} else if (LIST_FIRST(&dev_free)) {
178		si = LIST_FIRST(&dev_free);
179		LIST_REMOVE(si, si_hash);
180	} else {
181		si = devt_stash + stashed++;
182		si->si_flags |= SI_STASHED;
183	}
184	LIST_INIT(&si->si_names);
185	return (si);
186}
187
188dev_t
189makedev(int x, int y)
190{
191	struct specinfo *si;
192	udev_t	udev;
193	int hash;
194
195	if (x == umajor(NOUDEV) && y == uminor(NOUDEV))
196		Debugger("makedev of NOUDEV");
197	udev = (x << 8) | y;
198	hash = udev % DEVT_HASH;
199	LIST_FOREACH(si, &dev_hash[hash], si_hash) {
200		if (si->si_udev == udev)
201			return (si);
202	}
203	si = allocdev();
204	si->si_udev = udev;
205	LIST_INSERT_HEAD(&dev_hash[hash], si, si_hash);
206        return (si);
207}
208
209void
210freedev(dev_t dev)
211{
212	dev_t adev;
213
214	if (!free_devt)
215		return;
216	if (SLIST_FIRST(&dev->si_hlist))
217		return;
218	if (dev->si_devsw || dev->si_drv1 || dev->si_drv2)
219		return;
220	while (!LIST_EMPTY(&dev->si_names)) {
221		adev = LIST_FIRST(&dev->si_names);
222		adev->si_drv1 = NULL;
223		freedev(adev);
224	}
225	LIST_REMOVE(dev, si_hash);
226	if (dev->si_flags & SI_STASHED) {
227		bzero(dev, sizeof(*dev));
228		LIST_INSERT_HEAD(&dev_free, dev, si_hash);
229	} else {
230		FREE(dev, M_DEVT);
231	}
232}
233
234udev_t
235dev2udev(dev_t x)
236{
237	if (x == NODEV)
238		return NOUDEV;
239	return (x->si_udev);
240}
241
242dev_t
243udev2dev(udev_t x, int b)
244{
245
246	if (x == NOUDEV)
247		return (NODEV);
248	switch (b) {
249		case 0:
250			return makedev(umajor(x), uminor(x));
251		case 1:
252			return (NODEV);
253		default:
254			Debugger("udev2dev(...,X)");
255			return NODEV;
256	}
257}
258
259int
260uminor(udev_t dev)
261{
262	return(dev & 0xffff00ff);
263}
264
265int
266umajor(udev_t dev)
267{
268	return((dev & 0xff00) >> 8);
269}
270
271udev_t
272makeudev(int x, int y)
273{
274        return ((x << 8) | y);
275}
276
277dev_t
278make_dev(struct cdevsw *devsw, int minor, uid_t uid, gid_t gid, int perms, char *fmt, ...)
279{
280	dev_t	dev;
281	va_list ap;
282	int i;
283
284	dev = makedev(devsw->d_maj, minor);
285	if (dev->si_flags & SI_NAMED) {
286		printf( "WARNING: Driver mistake: repeat make_dev(\"%s\")\n",
287		    dev->si_name);
288		return (dev);
289	}
290	va_start(ap, fmt);
291	i = kvprintf(fmt, NULL, dev->si_name, 32, ap);
292	dev->si_name[i] = '\0';
293	va_end(ap);
294	dev->si_devsw = devsw;
295	dev->si_uid = uid;
296	dev->si_gid = gid;
297	dev->si_mode = perms;
298	dev->si_flags |= SI_NAMED;
299
300	if (devfs_create_hook)
301		devfs_create_hook(dev);
302	return (dev);
303}
304
305dev_t
306make_dev_alias(dev_t pdev, char *fmt, ...)
307{
308	dev_t	dev;
309	va_list ap;
310	int i;
311
312	dev = allocdev();
313	dev->si_flags |= SI_ALIAS;
314	dev->si_flags |= SI_NAMED;
315	dev->si_drv1 = pdev;
316	LIST_INSERT_HEAD(&pdev->si_names, dev, si_hash);
317
318	va_start(ap, fmt);
319	i = kvprintf(fmt, NULL, dev->si_name, 32, ap);
320	dev->si_name[i] = '\0';
321	va_end(ap);
322
323	if (devfs_create_hook)
324		devfs_create_hook(dev);
325	return (dev);
326}
327
328void
329destroy_dev(dev_t dev)
330{
331
332	if (!(dev->si_flags & SI_NAMED)) {
333		printf( "WARNING: Driver mistake: destroy_dev on %d/%d\n",
334		    major(dev), minor(dev));
335		return;
336	}
337
338	if (devfs_destroy_hook)
339		devfs_destroy_hook(dev);
340	dev->si_drv1 = 0;
341	dev->si_drv2 = 0;
342	dev->si_devsw = 0;
343	dev->si_flags &= ~SI_NAMED;
344	dev->si_flags &= ~SI_ALIAS;
345	freedev(dev);
346}
347
348const char *
349devtoname(dev_t dev)
350{
351	char *p;
352	int mynor;
353
354	if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') {
355		p = dev->si_name;
356		if (devsw(dev))
357			sprintf(p, "#%s/", devsw(dev)->d_name);
358		else
359			sprintf(p, "#%d/", major(dev));
360		p += strlen(p);
361		mynor = minor(dev);
362		if (mynor < 0 || mynor > 255)
363			sprintf(p, "%#x", (u_int)mynor);
364		else
365			sprintf(p, "%d", mynor);
366	}
367	return (dev->si_name);
368}
369
370int
371dev_stdclone(char *name, char **namep, char *stem, int *unit)
372{
373	int u, i;
374
375	if (bcmp(stem, name, strlen(stem)) != 0)
376		return (0);
377	i = strlen(stem);
378	if (!isdigit(name[i]))
379		return (0);
380	u = 0;
381	while (isdigit(name[i])) {
382		u *= 10;
383		u += name[i++] - '0';
384	}
385	*unit = u;
386	if (namep)
387		*namep = &name[i];
388	if (name[i])
389		return (2);
390	return (1);
391}
392
393/*
394 * Helper sysctl for devname(3).  We're given a {u}dev_t and return
395 * the name, if any, registered by the device driver.
396 */
397static int
398sysctl_devname(SYSCTL_HANDLER_ARGS)
399{
400	int error;
401	udev_t ud;
402	dev_t dev;
403
404	error = SYSCTL_IN(req, &ud, sizeof (ud));
405	if (error)
406		return (error);
407	dev = makedev(umajor(ud), uminor(ud));
408	if (dev->si_name[0] == '\0')
409		error = ENOENT;
410	else
411		error = SYSCTL_OUT(req, dev->si_name, strlen(dev->si_name) + 1);
412	freedev(dev);
413	return (error);
414}
415
416SYSCTL_PROC(_kern, OID_AUTO, devname, CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_ANYBODY,
417	NULL, 0, sysctl_devname, "", "devname(3) handler");
418
419