FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_conf.c
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: src/sys/kern/kern_conf.c,v 1.73.2.3 2003/03/10 02:18:25 imp Exp $
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/conf.h>
42 #include <sys/vnode.h>
43 #include <sys/queue.h>
44 #include <sys/device.h>
45 #include <sys/disk.h>
46 #include <machine/stdarg.h>
47
48 #include <sys/sysref2.h>
49
50 #include <sys/devfs.h>
51
52 int dev_ref_debug = 0;
53 SYSCTL_INT(_debug, OID_AUTO, dev_refs, CTLFLAG_RW, &dev_ref_debug, 0,
54 "Toggle device reference debug output");
55
56 /*
57 * cdev_t and u_dev_t primitives. Note that the major number is always
58 * extracted from si_umajor, not from si_devsw, because si_devsw is replaced
59 * when a device is destroyed.
60 */
61 int
62 major(cdev_t dev)
63 {
64 if (dev == NULL)
65 return NOUDEV;
66 return(dev->si_umajor);
67 }
68
69 int
70 minor(cdev_t dev)
71 {
72 if (dev == NULL)
73 return NOUDEV;
74 return(dev->si_uminor);
75 }
76
77 /*
78 * Compatibility function with old udev_t format to convert the
79 * non-consecutive minor space into a consecutive minor space.
80 */
81 int
82 lminor(cdev_t dev)
83 {
84 int y;
85
86 if (dev == NULL)
87 return NOUDEV;
88 y = dev->si_uminor;
89 if (y & 0x0000ff00)
90 return NOUDEV;
91 return ((y & 0xff) | (y >> 8));
92 }
93
94 /*
95 * Convert a device pointer to an old style device number. Return NOUDEV
96 * if the device is invalid or if the device (maj,min) cannot be converted
97 * to an old style udev_t.
98 */
99 udev_t
100 dev2udev(cdev_t dev)
101 {
102 if (dev == NULL)
103 return NOUDEV;
104
105 return (udev_t)dev->si_inode;
106 }
107
108 /*
109 * Convert a device number to a device pointer. The device is referenced
110 * ad-hoc, meaning that the caller should call reference_dev() if it wishes
111 * to keep ahold of the returned structure long term.
112 *
113 * The returned device is associated with the currently installed cdevsw
114 * for the requested major number. NULL is returned if the major number
115 * has not been registered.
116 */
117 cdev_t
118 udev2dev(udev_t x, int b)
119 {
120 if (x == NOUDEV || b != 0)
121 return(NULL);
122
123 return devfs_find_device_by_udev(x);
124 }
125
126 int
127 dev_is_good(cdev_t dev)
128 {
129 if (dev != NULL && dev->si_ops != &dead_dev_ops)
130 return(1);
131 return(0);
132 }
133
134 /*
135 * Various user device number extraction and conversion routines
136 */
137 int
138 uminor(udev_t dev)
139 {
140 if (dev == NOUDEV)
141 return(-1);
142 return(dev & 0xffff00ff);
143 }
144
145 int
146 umajor(udev_t dev)
147 {
148 if (dev == NOUDEV)
149 return(-1);
150 return((dev & 0xff00) >> 8);
151 }
152
153 udev_t
154 makeudev(int x, int y)
155 {
156 if ((x & 0xffffff00) || (y & 0x0000ff00))
157 return NOUDEV;
158 return ((x << 8) | y);
159 }
160
161 /*
162 * Create an internal or external device.
163 *
164 * This routine creates and returns an unreferenced ad-hoc entry for the
165 * device which will remain intact until the device is destroyed. If the
166 * caller intends to store the device pointer it must call reference_dev()
167 * to retain a real reference to the device.
168 *
169 * If an entry already exists, this function will set (or override)
170 * its cred requirements and name (XXX DEVFS interface).
171 */
172 cdev_t
173 make_dev(struct dev_ops *ops, int minor, uid_t uid, gid_t gid,
174 int perms, const char *fmt, ...)
175 {
176 cdev_t devfs_dev;
177 __va_list ap;
178
179 /*
180 * compile the cdevsw and install the device
181 */
182 compile_dev_ops(ops);
183
184 devfs_dev = devfs_new_cdev(ops, minor, NULL);
185 __va_start(ap, fmt);
186 kvsnrprintf(devfs_dev->si_name, sizeof(devfs_dev->si_name),
187 32, fmt, ap);
188 __va_end(ap);
189
190 devfs_debug(DEVFS_DEBUG_INFO,
191 "make_dev called for %s\n",
192 devfs_dev->si_name);
193 devfs_create_dev(devfs_dev, uid, gid, perms);
194
195 return (devfs_dev);
196 }
197
198 /*
199 * make_dev_covering has equivalent functionality to make_dev, except that it
200 * also takes the dev_ops of the underlying device. Hence this function should
201 * only be used by systems and drivers which create devices covering others
202 */
203 cdev_t
204 make_dev_covering(struct dev_ops *ops, struct dev_ops *bops, int minor,
205 uid_t uid, gid_t gid, int perms, const char *fmt, ...)
206 {
207 cdev_t devfs_dev;
208 __va_list ap;
209
210 /*
211 * compile the cdevsw and install the device
212 */
213 compile_dev_ops(ops);
214
215 devfs_dev = devfs_new_cdev(ops, minor, bops);
216 __va_start(ap, fmt);
217 kvsnrprintf(devfs_dev->si_name, sizeof(devfs_dev->si_name),
218 32, fmt, ap);
219 __va_end(ap);
220
221 devfs_debug(DEVFS_DEBUG_INFO,
222 "make_dev called for %s\n",
223 devfs_dev->si_name);
224 devfs_create_dev(devfs_dev, uid, gid, perms);
225
226 return (devfs_dev);
227 }
228
229
230
231 cdev_t
232 make_only_devfs_dev(struct dev_ops *ops, int minor, uid_t uid, gid_t gid,
233 int perms, const char *fmt, ...)
234 {
235 cdev_t devfs_dev;
236 __va_list ap;
237
238 /*
239 * compile the cdevsw and install the device
240 */
241 compile_dev_ops(ops);
242 devfs_dev = devfs_new_cdev(ops, minor, NULL);
243
244 /*
245 * Set additional fields (XXX DEVFS interface goes here)
246 */
247 __va_start(ap, fmt);
248 kvsnrprintf(devfs_dev->si_name, sizeof(devfs_dev->si_name),
249 32, fmt, ap);
250 __va_end(ap);
251
252 devfs_create_dev(devfs_dev, uid, gid, perms);
253
254 return (devfs_dev);
255 }
256
257 cdev_t
258 make_only_dev(struct dev_ops *ops, int minor, uid_t uid, gid_t gid,
259 int perms, const char *fmt, ...)
260 {
261 cdev_t devfs_dev;
262 __va_list ap;
263
264 /*
265 * compile the cdevsw and install the device
266 */
267 compile_dev_ops(ops);
268 devfs_dev = devfs_new_cdev(ops, minor, NULL);
269 devfs_dev->si_perms = perms;
270 devfs_dev->si_uid = uid;
271 devfs_dev->si_gid = gid;
272
273 /*
274 * Set additional fields (XXX DEVFS interface goes here)
275 */
276 __va_start(ap, fmt);
277 kvsnrprintf(devfs_dev->si_name, sizeof(devfs_dev->si_name),
278 32, fmt, ap);
279 __va_end(ap);
280
281 reference_dev(devfs_dev);
282
283 return (devfs_dev);
284 }
285
286 cdev_t
287 make_only_dev_covering(struct dev_ops *ops, struct dev_ops *bops, int minor,
288 uid_t uid, gid_t gid, int perms, const char *fmt, ...)
289 {
290 cdev_t devfs_dev;
291 __va_list ap;
292
293 /*
294 * compile the cdevsw and install the device
295 */
296 compile_dev_ops(ops);
297 devfs_dev = devfs_new_cdev(ops, minor, bops);
298 devfs_dev->si_perms = perms;
299 devfs_dev->si_uid = uid;
300 devfs_dev->si_gid = gid;
301
302 /*
303 * Set additional fields (XXX DEVFS interface goes here)
304 */
305 __va_start(ap, fmt);
306 kvsnrprintf(devfs_dev->si_name, sizeof(devfs_dev->si_name),
307 32, fmt, ap);
308 __va_end(ap);
309
310 reference_dev(devfs_dev);
311
312 return (devfs_dev);
313 }
314
315 void
316 destroy_only_dev(cdev_t dev)
317 {
318 release_dev(dev);
319 release_dev(dev);
320 release_dev(dev);
321 }
322
323 /*
324 * destroy_dev() removes the adhoc association for a device and revectors
325 * its ops to &dead_dev_ops.
326 *
327 * This routine releases the reference count associated with the ADHOC
328 * entry, plus releases the reference count held by the caller. What this
329 * means is that you should not call destroy_dev(make_dev(...)), because
330 * make_dev() does not bump the reference count (beyond what it needs to
331 * create the ad-hoc association). Any procedure that intends to destroy
332 * a device must have its own reference to it first.
333 */
334 void
335 destroy_dev(cdev_t dev)
336 {
337 if (dev) {
338 devfs_debug(DEVFS_DEBUG_DEBUG,
339 "destroy_dev called for %s\n",
340 dev->si_name);
341 devfs_destroy_dev(dev);
342 }
343 }
344
345 /*
346 * Make sure all asynchronous disk and devfs related operations have
347 * completed.
348 *
349 * Typically called prior to mountroot to ensure that all disks have
350 * been completely probed and on module unload to ensure that ops
351 * structures have been dereferenced.
352 */
353 void
354 sync_devs(void)
355 {
356 disk_config(NULL);
357 devfs_config();
358 disk_config(NULL);
359 devfs_config();
360 }
361
362 int
363 make_dev_alias(cdev_t target, const char *fmt, ...)
364 {
365 __va_list ap;
366 char *name;
367
368 __va_start(ap, fmt);
369 kvasnrprintf(&name, PATH_MAX, 32, fmt, ap);
370 __va_end(ap);
371
372 devfs_make_alias(name, target);
373 kvasfree(&name);
374
375 return 0;
376 }
377
378 int
379 destroy_dev_alias(cdev_t target, const char *fmt, ...)
380 {
381 __va_list ap;
382 char *name;
383
384 __va_start(ap, fmt);
385 kvasnrprintf(&name, PATH_MAX, 32, fmt, ap);
386 __va_end(ap);
387
388 devfs_destroy_alias(name, target);
389 kvasfree(&name);
390
391 return 0;
392 }
393
394 extern struct dev_ops default_dev_ops;
395
396 cdev_t
397 make_autoclone_dev(struct dev_ops *ops, struct devfs_bitmap *bitmap,
398 d_clone_t *nhandler, uid_t uid, gid_t gid, int perms, const char *fmt, ...)
399 {
400 __va_list ap;
401 cdev_t dev;
402 char *name;
403
404 __va_start(ap, fmt);
405 kvasnrprintf(&name, PATH_MAX, 32, fmt, ap);
406 __va_end(ap);
407
408 if (bitmap != NULL)
409 devfs_clone_bitmap_init(bitmap);
410
411 devfs_clone_handler_add(name, nhandler);
412 dev = make_dev_covering(&default_dev_ops, ops, 0xffff00ff,
413 uid, gid, perms, "%s", name);
414 kvasfree(&name);
415 return dev;
416 }
417
418 void
419 destroy_autoclone_dev(cdev_t dev, struct devfs_bitmap *bitmap)
420 {
421 if (dev == NULL)
422 return;
423
424 devfs_clone_handler_del(dev->si_name);
425
426 if (bitmap != NULL)
427 devfs_clone_bitmap_uninit(bitmap);
428
429 destroy_dev(dev);
430 }
431
432
433 /*
434 * Add a reference to a device. Callers generally add their own references
435 * when they are going to store a device node in a variable for long periods
436 * of time, to prevent a disassociation from free()ing the node.
437 *
438 * Also note that a caller that intends to call destroy_dev() must first
439 * obtain a reference on the device. The ad-hoc reference you get with
440 * make_dev() and friends is NOT sufficient to be able to call destroy_dev().
441 */
442 cdev_t
443 reference_dev(cdev_t dev)
444 {
445 //kprintf("reference_dev\n");
446
447 if (dev != NULL) {
448 sysref_get(&dev->si_sysref);
449 if (dev_ref_debug & 2) {
450 kprintf("reference dev %p %s(minor=%08x) refs=%d\n",
451 dev, devtoname(dev), dev->si_uminor,
452 dev->si_sysref.refcnt);
453 }
454 }
455 return(dev);
456 }
457
458 /*
459 * release a reference on a device. The device will be terminated when the
460 * last reference has been released.
461 *
462 * NOTE: we must use si_umajor to figure out the original major number,
463 * because si_ops could already be pointing at dead_dev_ops.
464 */
465 void
466 release_dev(cdev_t dev)
467 {
468 //kprintf("release_dev\n");
469
470 if (dev == NULL)
471 return;
472 sysref_put(&dev->si_sysref);
473 }
474
475 const char *
476 devtoname(cdev_t dev)
477 {
478 int mynor;
479 int len;
480 char *p;
481 const char *dname;
482
483 if (dev == NULL)
484 return("#nodev");
485 if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') {
486 p = dev->si_name;
487 len = sizeof(dev->si_name);
488 if ((dname = dev_dname(dev)) != NULL)
489 ksnprintf(p, len, "#%s/", dname);
490 else
491 ksnprintf(p, len, "#%d/", major(dev));
492 len -= strlen(p);
493 p += strlen(p);
494 mynor = minor(dev);
495 if (mynor < 0 || mynor > 255)
496 ksnprintf(p, len, "%#x", (u_int)mynor);
497 else
498 ksnprintf(p, len, "%d", mynor);
499 }
500 return (dev->si_name);
501 }
502
Cache object: 97a16c0cdc7cd304d19e989d6462fdfc
|