kern_conf.c revision 90736 
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 90736 2002-02-16 17:35:05Z green $
34 */
35
36#include <sys/param.h>
37#include <sys/kernel.h>
38#include <sys/systm.h>
39#include <sys/sysctl.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
50static struct cdevsw 	*cdevsw[NUMCDEVSW];
51
52static MALLOC_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 ready_for_devs;
75
76static int free_devt;
77SYSCTL_INT(_debug, OID_AUTO, free_devt, CTLFLAG_RW, &free_devt, 0, "");
78
79/* XXX: This is a hack */
80void disk_dev_synth(dev_t dev);
81
82struct cdevsw *
83devsw(dev_t dev)
84{
85	if (dev->si_devsw)
86		return (dev->si_devsw);
87	/* XXX: Hack around our backwards disk code */
88	disk_dev_synth(dev);
89	if (dev->si_devsw)
90		return (dev->si_devsw);
91	if (devfs_present)
92		return (NULL);
93        return(cdevsw[major(dev)]);
94}
95
96/*
97 *  Add a cdevsw entry
98 */
99
100int
101cdevsw_add(struct cdevsw *newentry)
102{
103
104	if (newentry->d_maj < 0 || newentry->d_maj >= NUMCDEVSW) {
105		printf("%s: ERROR: driver has bogus cdevsw->d_maj = %d\n",
106		    newentry->d_name, newentry->d_maj);
107		return (EINVAL);
108	}
109
110	if (cdevsw[newentry->d_maj]) {
111		printf("WARNING: \"%s\" is usurping \"%s\"'s cdevsw[]\n",
112		    newentry->d_name, cdevsw[newentry->d_maj]->d_name);
113	}
114
115	cdevsw[newentry->d_maj] = newentry;
116
117	return (0);
118}
119
120/*
121 *  Remove a cdevsw entry
122 */
123
124int
125cdevsw_remove(struct cdevsw *oldentry)
126{
127	if (oldentry->d_maj < 0 || oldentry->d_maj >= NUMCDEVSW) {
128		printf("%s: ERROR: driver has bogus cdevsw->d_maj = %d\n",
129		    oldentry->d_name, oldentry->d_maj);
130		return EINVAL;
131	}
132
133	cdevsw[oldentry->d_maj] = NULL;
134
135	return 0;
136}
137
138/*
139 * dev_t and u_dev_t primitives
140 */
141
142int
143major(dev_t x)
144{
145	if (x == NODEV)
146		return NOUDEV;
147	return((x->si_udev >> 8) & 0xff);
148}
149
150int
151minor(dev_t x)
152{
153	if (x == NODEV)
154		return NOUDEV;
155	return(x->si_udev & 0xffff00ff);
156}
157
158int
159dev2unit(dev_t x)
160{
161	int i;
162
163	if (x == NODEV)
164		return NOUDEV;
165	i = minor(x);
166	return ((i & 0xff) | (i >> 8));
167}
168
169int
170unit2minor(int unit)
171{
172
173	KASSERT(unit <= 0xffffff, ("Invalid unit (%d) in unit2minor", unit));
174	return ((unit & 0xff) | ((unit << 8) & ~0xffff));
175}
176
177static dev_t
178allocdev(void)
179{
180	static int stashed;
181	struct specinfo *si;
182
183	if (stashed >= DEVT_STASH) {
184		MALLOC(si, struct specinfo *, sizeof(*si), M_DEVT,
185		    M_USE_RESERVE | M_ZERO);
186	} else if (LIST_FIRST(&dev_free)) {
187		si = LIST_FIRST(&dev_free);
188		LIST_REMOVE(si, si_hash);
189	} else {
190		si = devt_stash + stashed++;
191		bzero(si, sizeof *si);
192	si->si_flags |= SI_STASHED;
193	}
194	LIST_INIT(&si->si_children);
195	TAILQ_INIT(&si->si_snapshots);
196	return (si);
197}
198
199dev_t
200makedev(int x, int y)
201{
202	struct specinfo *si;
203	udev_t	udev;
204	int hash;
205
206	if (x == umajor(NOUDEV) && y == uminor(NOUDEV))
207		panic("makedev of NOUDEV");
208	udev = (x << 8) | y;
209	hash = udev % DEVT_HASH;
210	LIST_FOREACH(si, &dev_hash[hash], si_hash) {
211		if (si->si_udev == udev)
212			return (si);
213	}
214	si = allocdev();
215	si->si_udev = udev;
216	LIST_INSERT_HEAD(&dev_hash[hash], si, si_hash);
217        return (si);
218}
219
220void
221freedev(dev_t dev)
222{
223
224	if (!free_devt)
225		return;
226	if (SLIST_FIRST(&dev->si_hlist))
227		return;
228	if (dev->si_devsw || dev->si_drv1 || dev->si_drv2)
229		return;
230	LIST_REMOVE(dev, si_hash);
231	if (dev->si_flags & SI_STASHED) {
232		bzero(dev, sizeof(*dev));
233		dev->si_flags |= SI_STASHED;
234		LIST_INSERT_HEAD(&dev_free, dev, si_hash);
235	} else {
236		FREE(dev, M_DEVT);
237	}
238}
239
240udev_t
241dev2udev(dev_t x)
242{
243	if (x == NODEV)
244		return NOUDEV;
245	return (x->si_udev);
246}
247
248dev_t
249udev2dev(udev_t x, int b)
250{
251
252	if (x == NOUDEV)
253		return (NODEV);
254	switch (b) {
255		case 0:
256			return makedev(umajor(x), uminor(x));
257		case 1:
258			return (NODEV);
259		default:
260			Debugger("udev2dev(...,X)");
261			return NODEV;
262	}
263}
264
265int
266uminor(udev_t dev)
267{
268	return(dev & 0xffff00ff);
269}
270
271int
272umajor(udev_t dev)
273{
274	return((dev & 0xff00) >> 8);
275}
276
277udev_t
278makeudev(int x, int y)
279{
280        return ((x << 8) | y);
281}
282
283dev_t
284make_dev(struct cdevsw *devsw, int minor, uid_t uid, gid_t gid, int perms, const char *fmt, ...)
285{
286	dev_t	dev;
287	va_list ap;
288	int i;
289
290	KASSERT(umajor(makeudev(devsw->d_maj, minor)) == devsw->d_maj,
291	    ("Invalid minor (%d) in make_dev", minor));
292
293	if (!ready_for_devs) {
294		printf("WARNING: Driver mistake: make_dev(%s) called before SI_SUB_DRIVERS\n",
295		       fmt);
296		/* XXX panic here once drivers are cleaned up */
297	}
298
299	dev = makedev(devsw->d_maj, minor);
300	if (dev->si_flags & SI_NAMED) {
301		printf( "WARNING: Driver mistake: repeat make_dev(\"%s\")\n",
302		    dev->si_name);
303		panic("don't do that");
304		return (dev);
305	}
306	va_start(ap, fmt);
307	i = kvprintf(fmt, NULL, dev->si_name, 32, ap);
308	dev->si_name[i] = '\0';
309	va_end(ap);
310	dev->si_devsw = devsw;
311	dev->si_uid = uid;
312	dev->si_gid = gid;
313	dev->si_mode = perms;
314	dev->si_flags |= SI_NAMED;
315
316	if (devfs_create_hook)
317		devfs_create_hook(dev);
318	return (dev);
319}
320
321int
322dev_named(dev_t pdev, const char *name)
323{
324	dev_t cdev;
325
326	if (strcmp(devtoname(pdev), name) == 0)
327		return (1);
328	LIST_FOREACH(cdev, &pdev->si_children, si_siblings)
329		if (strcmp(devtoname(cdev), name) == 0)
330			return (1);
331	return (0);
332}
333
334void
335dev_depends(dev_t pdev, dev_t cdev)
336{
337
338	cdev->si_parent = pdev;
339	cdev->si_flags |= SI_CHILD;
340	LIST_INSERT_HEAD(&pdev->si_children, cdev, si_siblings);
341}
342
343dev_t
344make_dev_alias(dev_t pdev, const char *fmt, ...)
345{
346	dev_t	dev;
347	va_list ap;
348	int i;
349
350	dev = allocdev();
351	dev->si_flags |= SI_ALIAS;
352	dev->si_flags |= SI_NAMED;
353	dev_depends(pdev, dev);
354	va_start(ap, fmt);
355	i = kvprintf(fmt, NULL, dev->si_name, 32, ap);
356	dev->si_name[i] = '\0';
357	va_end(ap);
358
359	if (devfs_create_hook)
360		devfs_create_hook(dev);
361	return (dev);
362}
363
364void
365revoke_and_destroy_dev(dev_t dev)
366{
367	struct vnode *vp;
368
369	GIANT_REQUIRED;
370
371	vp = SLIST_FIRST(&dev->si_hlist);
372	if (vp != NULL)
373		VOP_REVOKE(vp, REVOKEALL);
374	destroy_dev(dev);
375}
376
377void
378destroy_dev(dev_t dev)
379{
380
381	if (!(dev->si_flags & SI_NAMED)) {
382		printf( "WARNING: Driver mistake: destroy_dev on %d/%d\n",
383		    major(dev), minor(dev));
384		panic("don't do that");
385		return;
386	}
387
388	if (devfs_destroy_hook)
389		devfs_destroy_hook(dev);
390	if (dev->si_flags & SI_CHILD) {
391		LIST_REMOVE(dev, si_siblings);
392		dev->si_flags &= ~SI_CHILD;
393	}
394	while (!LIST_EMPTY(&dev->si_children))
395		destroy_dev(LIST_FIRST(&dev->si_children));
396	dev->si_drv1 = 0;
397	dev->si_drv2 = 0;
398	dev->si_devsw = 0;
399	dev->si_flags &= ~SI_NAMED;
400	dev->si_flags &= ~SI_ALIAS;
401	freedev(dev);
402}
403
404const char *
405devtoname(dev_t dev)
406{
407	char *p;
408	int mynor;
409
410	if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') {
411		p = dev->si_name;
412		if (devsw(dev))
413			sprintf(p, "#%s/", devsw(dev)->d_name);
414		else
415			sprintf(p, "#%d/", major(dev));
416		p += strlen(p);
417		mynor = minor(dev);
418		if (mynor < 0 || mynor > 255)
419			sprintf(p, "%#x", (u_int)mynor);
420		else
421			sprintf(p, "%d", mynor);
422	}
423	return (dev->si_name);
424}
425
426int
427dev_stdclone(char *name, char **namep, char *stem, int *unit)
428{
429	int u, i;
430
431	i = strlen(stem);
432	if (bcmp(stem, name, i) != 0)
433		return (0);
434	if (!isdigit(name[i]))
435		return (0);
436	u = 0;
437	if (name[i] == '0' && isdigit(name[i+1]))
438		return (0);
439	while (isdigit(name[i])) {
440		u *= 10;
441		u += name[i++] - '0';
442	}
443	*unit = u;
444	if (namep)
445		*namep = &name[i];
446	if (name[i])
447		return (2);
448	return (1);
449}
450
451/*
452 * Helper sysctl for devname(3).  We're given a {u}dev_t and return
453 * the name, if any, registered by the device driver.
454 */
455static int
456sysctl_devname(SYSCTL_HANDLER_ARGS)
457{
458	int error;
459	udev_t ud;
460	dev_t dev;
461
462	error = SYSCTL_IN(req, &ud, sizeof (ud));
463	if (error)
464		return (error);
465	if (ud == NOUDEV)
466		return(EINVAL);
467	dev = makedev(umajor(ud), uminor(ud));
468	if (dev->si_name[0] == '\0')
469		error = ENOENT;
470	else
471		error = SYSCTL_OUT(req, dev->si_name, strlen(dev->si_name) + 1);
472	freedev(dev);
473	return (error);
474}
475
476SYSCTL_PROC(_kern, OID_AUTO, devname, CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_ANYBODY,
477	NULL, 0, sysctl_devname, "", "devname(3) handler");
478
479/*
480 * Set ready_for_devs; prior to this point, device creation is not allowed.
481 */
482static void
483dev_set_ready(void *junk)
484{
485	ready_for_devs = 1;
486}
487
488SYSINIT(dev_ready, SI_SUB_DEVFS, SI_ORDER_FIRST, dev_set_ready, NULL);
489