FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_conf.c
1 /*-
2 * Copyright (c) 1999-2002 Poul-Henning Kamp
3 * 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 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD: releng/5.1/sys/kern/kern_conf.c 113441 2003-04-13 15:27:49Z phk $
27 */
28
29 #include <sys/param.h>
30 #include <sys/kernel.h>
31 #include <sys/systm.h>
32 #include <sys/bio.h>
33 #include <sys/lock.h>
34 #include <sys/mutex.h>
35 #include <sys/sysctl.h>
36 #include <sys/module.h>
37 #include <sys/malloc.h>
38 #include <sys/conf.h>
39 #include <sys/vnode.h>
40 #include <sys/queue.h>
41 #include <sys/ctype.h>
42 #include <machine/stdarg.h>
43
44 static MALLOC_DEFINE(M_DEVT, "dev_t", "dev_t storage");
45
46 /* Built at compile time from sys/conf/majors */
47 extern unsigned char reserved_majors[256];
48
49 /*
50 * This is the number of hash-buckets. Experiements with 'real-life'
51 * udev_t's show that a prime halfway between two powers of two works
52 * best.
53 */
54 #define DEVT_HASH 83
55
56 /* The number of dev_t's we can create before malloc(9) kick in. */
57 #define DEVT_STASH 50
58
59 static struct cdev devt_stash[DEVT_STASH];
60
61 static LIST_HEAD(, cdev) dev_hash[DEVT_HASH];
62
63 static LIST_HEAD(, cdev) dev_free;
64
65 static int ready_for_devs;
66
67 static int free_devt;
68 SYSCTL_INT(_debug, OID_AUTO, free_devt, CTLFLAG_RW, &free_devt, 0, "");
69
70 /* Define a dead_cdevsw for use when devices leave unexpectedly. */
71
72 static int
73 enxio(void)
74 {
75 return (ENXIO);
76 }
77
78 #define dead_open (d_open_t *)enxio
79 #define dead_close (d_close_t *)enxio
80 #define dead_read (d_read_t *)enxio
81 #define dead_write (d_write_t *)enxio
82 #define dead_ioctl (d_ioctl_t *)enxio
83 #define dead_poll nopoll
84 #define dead_mmap nommap
85
86 static void
87 dead_strategy(struct bio *bp)
88 {
89
90 biofinish(bp, NULL, ENXIO);
91 }
92
93 #define dead_dump (dumper_t *)enxio
94
95 #define dead_kqfilter (d_kqfilter_t *)enxio
96
97 static struct cdevsw dead_cdevsw = {
98 .d_open = dead_open,
99 .d_close = dead_close,
100 .d_read = dead_read,
101 .d_write = dead_write,
102 .d_ioctl = dead_ioctl,
103 .d_poll = dead_poll,
104 .d_mmap = dead_mmap,
105 .d_strategy = dead_strategy,
106 .d_name = "dead",
107 .d_maj = 255,
108 .d_dump = dead_dump,
109 .d_kqfilter = dead_kqfilter
110 };
111
112
113 struct cdevsw *
114 devsw(dev_t dev)
115 {
116 if (dev->si_devsw)
117 return (dev->si_devsw);
118 return (&dead_cdevsw);
119 }
120
121 /*
122 * dev_t and u_dev_t primitives
123 */
124
125 int
126 major(dev_t x)
127 {
128 if (x == NODEV)
129 return NOUDEV;
130 return((x->si_udev >> 8) & 0xff);
131 }
132
133 int
134 minor(dev_t x)
135 {
136 if (x == NODEV)
137 return NOUDEV;
138 return(x->si_udev & 0xffff00ff);
139 }
140
141 int
142 dev2unit(dev_t x)
143 {
144 int i;
145
146 if (x == NODEV)
147 return NOUDEV;
148 i = minor(x);
149 return ((i & 0xff) | (i >> 8));
150 }
151
152 int
153 unit2minor(int unit)
154 {
155
156 KASSERT(unit <= 0xffffff, ("Invalid unit (%d) in unit2minor", unit));
157 return ((unit & 0xff) | ((unit << 8) & ~0xffff));
158 }
159
160 static dev_t
161 allocdev(void)
162 {
163 static int stashed;
164 struct cdev *si;
165
166 if (LIST_FIRST(&dev_free)) {
167 si = LIST_FIRST(&dev_free);
168 LIST_REMOVE(si, si_hash);
169 } else if (stashed >= DEVT_STASH) {
170 MALLOC(si, struct cdev *, sizeof(*si), M_DEVT,
171 M_USE_RESERVE | M_ZERO | M_WAITOK);
172 } else {
173 si = devt_stash + stashed++;
174 bzero(si, sizeof *si);
175 si->si_flags |= SI_STASHED;
176 }
177 si->__si_namebuf[0] = '\0';
178 si->si_name = si->__si_namebuf;
179 LIST_INIT(&si->si_children);
180 TAILQ_INIT(&si->si_snapshots);
181 return (si);
182 }
183
184 dev_t
185 makedev(int x, int y)
186 {
187 struct cdev *si;
188 udev_t udev;
189 int hash;
190
191 if (x == umajor(NOUDEV) && y == uminor(NOUDEV))
192 panic("makedev of NOUDEV");
193 udev = (x << 8) | y;
194 hash = udev % DEVT_HASH;
195 LIST_FOREACH(si, &dev_hash[hash], si_hash) {
196 if (si->si_udev == udev)
197 return (si);
198 }
199 si = allocdev();
200 si->si_udev = udev;
201 LIST_INSERT_HEAD(&dev_hash[hash], si, si_hash);
202 return (si);
203 }
204
205 void
206 freedev(dev_t dev)
207 {
208
209 if (!free_devt)
210 return;
211 if (SLIST_FIRST(&dev->si_hlist))
212 return;
213 if (dev->si_devsw || dev->si_drv1 || dev->si_drv2)
214 return;
215 LIST_REMOVE(dev, si_hash);
216 if (dev->si_flags & SI_STASHED) {
217 bzero(dev, sizeof(*dev));
218 dev->si_flags |= SI_STASHED;
219 LIST_INSERT_HEAD(&dev_free, dev, si_hash);
220 } else {
221 FREE(dev, M_DEVT);
222 }
223 }
224
225 udev_t
226 dev2udev(dev_t x)
227 {
228 if (x == NODEV)
229 return NOUDEV;
230 return (x->si_udev);
231 }
232
233 dev_t
234 udev2dev(udev_t x, int b)
235 {
236
237 if (x == NOUDEV)
238 return (NODEV);
239 switch (b) {
240 case 0:
241 return makedev(umajor(x), uminor(x));
242 case 1:
243 return (NODEV);
244 default:
245 Debugger("udev2dev(...,X)");
246 return NODEV;
247 }
248 }
249
250 int
251 uminor(udev_t dev)
252 {
253 return(dev & 0xffff00ff);
254 }
255
256 int
257 umajor(udev_t dev)
258 {
259 return((dev & 0xff00) >> 8);
260 }
261
262 udev_t
263 makeudev(int x, int y)
264 {
265 return ((x << 8) | y);
266 }
267
268 dev_t
269 make_dev(struct cdevsw *devsw, int minor, uid_t uid, gid_t gid, int perms, const char *fmt, ...)
270 {
271 dev_t dev;
272 va_list ap;
273 int i;
274
275 KASSERT((minor & ~0xffff00ff) == 0,
276 ("Invalid minor (0x%x) in make_dev", minor));
277
278 if (devsw->d_open == NULL) devsw->d_open = noopen;
279 if (devsw->d_close == NULL) devsw->d_close = noclose;
280 if (devsw->d_read == NULL) devsw->d_read = noread;
281 if (devsw->d_write == NULL) devsw->d_write = nowrite;
282 if (devsw->d_ioctl == NULL) devsw->d_ioctl = noioctl;
283 if (devsw->d_poll == NULL) devsw->d_poll = nopoll;
284 if (devsw->d_mmap == NULL) devsw->d_mmap = nommap;
285 if (devsw->d_strategy == NULL) devsw->d_strategy = nostrategy;
286 if (devsw->d_dump == NULL) devsw->d_dump = nodump;
287 if (devsw->d_kqfilter == NULL) devsw->d_kqfilter = nokqfilter;
288
289 if (devsw->d_maj == MAJOR_AUTO) {
290 for (i = NUMCDEVSW - 1; i > 0; i--)
291 if (reserved_majors[i] != i)
292 break;
293 KASSERT(i > 0, ("Out of major numbers (%s)", devsw->d_name));
294 devsw->d_maj = i;
295 reserved_majors[i] = i;
296 } else {
297 if (devsw->d_maj == 256) /* XXX: tty_cons.c is magic */
298 devsw->d_maj = 0;
299 KASSERT(devsw->d_maj >= 0 && devsw->d_maj < 256,
300 ("Invalid major (%d) in make_dev", devsw->d_maj));
301 if (reserved_majors[devsw->d_maj] != devsw->d_maj) {
302 printf("WARNING: driver \"%s\" used %s %d\n",
303 devsw->d_name, "unreserved major device number",
304 devsw->d_maj);
305 reserved_majors[devsw->d_maj] = devsw->d_maj;
306 }
307 }
308
309 if (!ready_for_devs) {
310 printf("WARNING: Driver mistake: make_dev(%s) called before SI_SUB_DRIVERS\n",
311 fmt);
312 /* XXX panic here once drivers are cleaned up */
313 }
314
315 dev = makedev(devsw->d_maj, minor);
316 if (dev->si_flags & SI_NAMED) {
317 printf( "WARNING: Driver mistake: repeat make_dev(\"%s\")\n",
318 dev->si_name);
319 panic("don't do that");
320 return (dev);
321 }
322 va_start(ap, fmt);
323 i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap);
324 if (i > (sizeof dev->__si_namebuf - 1)) {
325 printf("WARNING: Device name truncated! (%s)",
326 dev->__si_namebuf);
327 }
328 va_end(ap);
329 dev->si_devsw = devsw;
330 dev->si_uid = uid;
331 dev->si_gid = gid;
332 dev->si_mode = perms;
333 dev->si_flags |= SI_NAMED;
334
335 devfs_create(dev);
336 return (dev);
337 }
338
339 int
340 dev_named(dev_t pdev, const char *name)
341 {
342 dev_t cdev;
343
344 if (strcmp(devtoname(pdev), name) == 0)
345 return (1);
346 LIST_FOREACH(cdev, &pdev->si_children, si_siblings)
347 if (strcmp(devtoname(cdev), name) == 0)
348 return (1);
349 return (0);
350 }
351
352 void
353 dev_depends(dev_t pdev, dev_t cdev)
354 {
355
356 cdev->si_parent = pdev;
357 cdev->si_flags |= SI_CHILD;
358 LIST_INSERT_HEAD(&pdev->si_children, cdev, si_siblings);
359 }
360
361 dev_t
362 make_dev_alias(dev_t pdev, const char *fmt, ...)
363 {
364 dev_t dev;
365 va_list ap;
366 int i;
367
368 dev = allocdev();
369 dev->si_flags |= SI_ALIAS;
370 dev->si_flags |= SI_NAMED;
371 dev_depends(pdev, dev);
372 va_start(ap, fmt);
373 i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap);
374 if (i > (sizeof dev->__si_namebuf - 1)) {
375 printf("WARNING: Device name truncated! (%s)",
376 dev->__si_namebuf);
377 }
378 va_end(ap);
379
380 devfs_create(dev);
381 return (dev);
382 }
383
384 void
385 revoke_and_destroy_dev(dev_t dev)
386 {
387 struct vnode *vp;
388
389 GIANT_REQUIRED;
390
391 vp = SLIST_FIRST(&dev->si_hlist);
392 if (vp != NULL)
393 VOP_REVOKE(vp, REVOKEALL);
394 destroy_dev(dev);
395 }
396
397 void
398 destroy_dev(dev_t dev)
399 {
400
401 if (!(dev->si_flags & SI_NAMED)) {
402 printf( "WARNING: Driver mistake: destroy_dev on %d/%d\n",
403 major(dev), minor(dev));
404 panic("don't do that");
405 return;
406 }
407
408 devfs_destroy(dev);
409 if (dev->si_flags & SI_CHILD) {
410 LIST_REMOVE(dev, si_siblings);
411 dev->si_flags &= ~SI_CHILD;
412 }
413 while (!LIST_EMPTY(&dev->si_children))
414 destroy_dev(LIST_FIRST(&dev->si_children));
415 dev->si_drv1 = 0;
416 dev->si_drv2 = 0;
417 dev->si_devsw = 0;
418 bzero(&dev->__si_u, sizeof(dev->__si_u));
419 dev->si_flags &= ~SI_NAMED;
420 dev->si_flags &= ~SI_ALIAS;
421 freedev(dev);
422 }
423
424 const char *
425 devtoname(dev_t dev)
426 {
427 char *p;
428 int mynor;
429
430 if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') {
431 p = dev->si_name;
432 if (devsw(dev))
433 sprintf(p, "#%s/", devsw(dev)->d_name);
434 else
435 sprintf(p, "#%d/", major(dev));
436 p += strlen(p);
437 mynor = minor(dev);
438 if (mynor < 0 || mynor > 255)
439 sprintf(p, "%#x", (u_int)mynor);
440 else
441 sprintf(p, "%d", mynor);
442 }
443 return (dev->si_name);
444 }
445
446 int
447 dev_stdclone(char *name, char **namep, const char *stem, int *unit)
448 {
449 int u, i;
450
451 i = strlen(stem);
452 if (bcmp(stem, name, i) != 0)
453 return (0);
454 if (!isdigit(name[i]))
455 return (0);
456 u = 0;
457 if (name[i] == '' && isdigit(name[i+1]))
458 return (0);
459 while (isdigit(name[i])) {
460 u *= 10;
461 u += name[i++] - '';
462 }
463 if (u > 0xffffff)
464 return (0);
465 *unit = u;
466 if (namep)
467 *namep = &name[i];
468 if (name[i])
469 return (2);
470 return (1);
471 }
472
473 /*
474 * Helper sysctl for devname(3). We're given a {u}dev_t and return
475 * the name, if any, registered by the device driver.
476 */
477 static int
478 sysctl_devname(SYSCTL_HANDLER_ARGS)
479 {
480 int error;
481 udev_t ud;
482 dev_t dev;
483
484 error = SYSCTL_IN(req, &ud, sizeof (ud));
485 if (error)
486 return (error);
487 if (ud == NOUDEV)
488 return(EINVAL);
489 dev = makedev(umajor(ud), uminor(ud));
490 if (dev->si_name[0] == '\0')
491 error = ENOENT;
492 else
493 error = SYSCTL_OUT(req, dev->si_name, strlen(dev->si_name) + 1);
494 freedev(dev);
495 return (error);
496 }
497
498 SYSCTL_PROC(_kern, OID_AUTO, devname, CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_ANYBODY,
499 NULL, 0, sysctl_devname, "", "devname(3) handler");
500
501 /*
502 * Set ready_for_devs; prior to this point, device creation is not allowed.
503 */
504 static void
505 dev_set_ready(void *junk)
506 {
507 ready_for_devs = 1;
508 }
509
510 SYSINIT(dev_ready, SI_SUB_DEVFS, SI_ORDER_FIRST, dev_set_ready, NULL);
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