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1da177e4 LT |
1 | /* |
2 | * kobject.c - library routines for handling generic kernel objects | |
3 | * | |
4 | * Copyright (c) 2002-2003 Patrick Mochel <mochel@osdl.org> | |
5 | * | |
6 | * This file is released under the GPLv2. | |
7 | * | |
8 | * | |
9 | * Please see the file Documentation/kobject.txt for critical information | |
10 | * about using the kobject interface. | |
11 | */ | |
12 | ||
13 | #include <linux/kobject.h> | |
14 | #include <linux/string.h> | |
15 | #include <linux/module.h> | |
16 | #include <linux/stat.h> | |
4e57b681 | 17 | #include <linux/slab.h> |
1da177e4 LT |
18 | |
19 | /** | |
20 | * populate_dir - populate directory with attributes. | |
21 | * @kobj: object we're working on. | |
22 | * | |
23 | * Most subsystems have a set of default attributes that | |
24 | * are associated with an object that registers with them. | |
25 | * This is a helper called during object registration that | |
26 | * loops through the default attributes of the subsystem | |
27 | * and creates attributes files for them in sysfs. | |
28 | * | |
29 | */ | |
30 | ||
31 | static int populate_dir(struct kobject * kobj) | |
32 | { | |
33 | struct kobj_type * t = get_ktype(kobj); | |
34 | struct attribute * attr; | |
35 | int error = 0; | |
36 | int i; | |
37 | ||
38 | if (t && t->default_attrs) { | |
39 | for (i = 0; (attr = t->default_attrs[i]) != NULL; i++) { | |
40 | if ((error = sysfs_create_file(kobj,attr))) | |
41 | break; | |
42 | } | |
43 | } | |
44 | return error; | |
45 | } | |
46 | ||
47 | static int create_dir(struct kobject * kobj) | |
48 | { | |
49 | int error = 0; | |
50 | if (kobject_name(kobj)) { | |
51 | error = sysfs_create_dir(kobj); | |
52 | if (!error) { | |
53 | if ((error = populate_dir(kobj))) | |
54 | sysfs_remove_dir(kobj); | |
55 | } | |
56 | } | |
57 | return error; | |
58 | } | |
59 | ||
60 | static inline struct kobject * to_kobj(struct list_head * entry) | |
61 | { | |
62 | return container_of(entry,struct kobject,entry); | |
63 | } | |
64 | ||
65 | static int get_kobj_path_length(struct kobject *kobj) | |
66 | { | |
67 | int length = 1; | |
68 | struct kobject * parent = kobj; | |
69 | ||
70 | /* walk up the ancestors until we hit the one pointing to the | |
71 | * root. | |
72 | * Add 1 to strlen for leading '/' of each level. | |
73 | */ | |
74 | do { | |
b365b3da CE |
75 | if (kobject_name(parent) == NULL) |
76 | return 0; | |
1da177e4 LT |
77 | length += strlen(kobject_name(parent)) + 1; |
78 | parent = parent->parent; | |
79 | } while (parent); | |
80 | return length; | |
81 | } | |
82 | ||
83 | static void fill_kobj_path(struct kobject *kobj, char *path, int length) | |
84 | { | |
85 | struct kobject * parent; | |
86 | ||
87 | --length; | |
88 | for (parent = kobj; parent; parent = parent->parent) { | |
89 | int cur = strlen(kobject_name(parent)); | |
90 | /* back up enough to print this name with '/' */ | |
91 | length -= cur; | |
92 | strncpy (path + length, kobject_name(parent), cur); | |
93 | *(path + --length) = '/'; | |
94 | } | |
95 | ||
96 | pr_debug("%s: path = '%s'\n",__FUNCTION__,path); | |
97 | } | |
98 | ||
99 | /** | |
100 | * kobject_get_path - generate and return the path associated with a given kobj | |
101 | * and kset pair. The result must be freed by the caller with kfree(). | |
102 | * | |
103 | * @kobj: kobject in question, with which to build the path | |
104 | * @gfp_mask: the allocation type used to allocate the path | |
105 | */ | |
fd4f2df2 | 106 | char *kobject_get_path(struct kobject *kobj, gfp_t gfp_mask) |
1da177e4 LT |
107 | { |
108 | char *path; | |
109 | int len; | |
110 | ||
111 | len = get_kobj_path_length(kobj); | |
b365b3da CE |
112 | if (len == 0) |
113 | return NULL; | |
1da177e4 LT |
114 | path = kmalloc(len, gfp_mask); |
115 | if (!path) | |
116 | return NULL; | |
117 | memset(path, 0x00, len); | |
118 | fill_kobj_path(kobj, path, len); | |
119 | ||
120 | return path; | |
121 | } | |
122 | ||
123 | /** | |
124 | * kobject_init - initialize object. | |
125 | * @kobj: object in question. | |
126 | */ | |
127 | void kobject_init(struct kobject * kobj) | |
128 | { | |
129 | kref_init(&kobj->kref); | |
130 | INIT_LIST_HEAD(&kobj->entry); | |
4508a7a7 | 131 | init_waitqueue_head(&kobj->poll); |
1da177e4 LT |
132 | kobj->kset = kset_get(kobj->kset); |
133 | } | |
134 | ||
135 | ||
136 | /** | |
137 | * unlink - remove kobject from kset list. | |
138 | * @kobj: kobject. | |
139 | * | |
140 | * Remove the kobject from the kset list and decrement | |
141 | * its parent's refcount. | |
142 | * This is separated out, so we can use it in both | |
143 | * kobject_del() and kobject_add() on error. | |
144 | */ | |
145 | ||
146 | static void unlink(struct kobject * kobj) | |
147 | { | |
148 | if (kobj->kset) { | |
149 | spin_lock(&kobj->kset->list_lock); | |
150 | list_del_init(&kobj->entry); | |
151 | spin_unlock(&kobj->kset->list_lock); | |
152 | } | |
153 | kobject_put(kobj); | |
154 | } | |
155 | ||
156 | /** | |
157 | * kobject_add - add an object to the hierarchy. | |
158 | * @kobj: object. | |
159 | */ | |
160 | ||
161 | int kobject_add(struct kobject * kobj) | |
162 | { | |
163 | int error = 0; | |
164 | struct kobject * parent; | |
165 | ||
166 | if (!(kobj = kobject_get(kobj))) | |
167 | return -ENOENT; | |
168 | if (!kobj->k_name) | |
169 | kobj->k_name = kobj->name; | |
c171fef5 GKH |
170 | if (!kobj->k_name) { |
171 | pr_debug("kobject attempted to be registered with no name!\n"); | |
172 | WARN_ON(1); | |
173 | return -EINVAL; | |
174 | } | |
1da177e4 LT |
175 | parent = kobject_get(kobj->parent); |
176 | ||
177 | pr_debug("kobject %s: registering. parent: %s, set: %s\n", | |
178 | kobject_name(kobj), parent ? kobject_name(parent) : "<NULL>", | |
179 | kobj->kset ? kobj->kset->kobj.name : "<NULL>" ); | |
180 | ||
181 | if (kobj->kset) { | |
182 | spin_lock(&kobj->kset->list_lock); | |
183 | ||
184 | if (!parent) | |
185 | parent = kobject_get(&kobj->kset->kobj); | |
186 | ||
187 | list_add_tail(&kobj->entry,&kobj->kset->list); | |
188 | spin_unlock(&kobj->kset->list_lock); | |
189 | } | |
190 | kobj->parent = parent; | |
191 | ||
192 | error = create_dir(kobj); | |
193 | if (error) { | |
194 | /* unlink does the kobject_put() for us */ | |
195 | unlink(kobj); | |
196 | if (parent) | |
197 | kobject_put(parent); | |
dcd0da00 GKH |
198 | |
199 | /* be noisy on error issues */ | |
200 | if (error == -EEXIST) | |
183bd5b3 | 201 | printk("kobject_add failed for %s with -EEXIST, " |
dcd0da00 GKH |
202 | "don't try to register things with the " |
203 | "same name in the same directory.\n", | |
204 | kobject_name(kobj)); | |
205 | else | |
183bd5b3 | 206 | printk("kobject_add failed for %s (%d)\n", |
dcd0da00 | 207 | kobject_name(kobj), error); |
183bd5b3 | 208 | dump_stack(); |
1da177e4 LT |
209 | } |
210 | ||
211 | return error; | |
212 | } | |
213 | ||
214 | ||
215 | /** | |
216 | * kobject_register - initialize and add an object. | |
217 | * @kobj: object in question. | |
218 | */ | |
219 | ||
220 | int kobject_register(struct kobject * kobj) | |
221 | { | |
dcd0da00 | 222 | int error = -EINVAL; |
1da177e4 LT |
223 | if (kobj) { |
224 | kobject_init(kobj); | |
225 | error = kobject_add(kobj); | |
dcd0da00 | 226 | if (!error) |
312c004d | 227 | kobject_uevent(kobj, KOBJ_ADD); |
dcd0da00 | 228 | } |
1da177e4 LT |
229 | return error; |
230 | } | |
231 | ||
232 | ||
233 | /** | |
234 | * kobject_set_name - Set the name of an object | |
235 | * @kobj: object. | |
67be2dd1 | 236 | * @fmt: format string used to build the name |
1da177e4 LT |
237 | * |
238 | * If strlen(name) >= KOBJ_NAME_LEN, then use a dynamically allocated | |
239 | * string that @kobj->k_name points to. Otherwise, use the static | |
240 | * @kobj->name array. | |
241 | */ | |
1da177e4 LT |
242 | int kobject_set_name(struct kobject * kobj, const char * fmt, ...) |
243 | { | |
244 | int error = 0; | |
245 | int limit = KOBJ_NAME_LEN; | |
246 | int need; | |
247 | va_list args; | |
248 | char * name; | |
249 | ||
250 | /* | |
251 | * First, try the static array | |
252 | */ | |
253 | va_start(args,fmt); | |
254 | need = vsnprintf(kobj->name,limit,fmt,args); | |
255 | va_end(args); | |
256 | if (need < limit) | |
257 | name = kobj->name; | |
258 | else { | |
259 | /* | |
260 | * Need more space? Allocate it and try again | |
261 | */ | |
262 | limit = need + 1; | |
263 | name = kmalloc(limit,GFP_KERNEL); | |
264 | if (!name) { | |
265 | error = -ENOMEM; | |
266 | goto Done; | |
267 | } | |
268 | va_start(args,fmt); | |
269 | need = vsnprintf(name,limit,fmt,args); | |
270 | va_end(args); | |
271 | ||
272 | /* Still? Give up. */ | |
273 | if (need >= limit) { | |
274 | kfree(name); | |
275 | error = -EFAULT; | |
276 | goto Done; | |
277 | } | |
278 | } | |
279 | ||
280 | /* Free the old name, if necessary. */ | |
281 | if (kobj->k_name && kobj->k_name != kobj->name) | |
282 | kfree(kobj->k_name); | |
283 | ||
284 | /* Now, set the new name */ | |
285 | kobj->k_name = name; | |
286 | Done: | |
287 | return error; | |
288 | } | |
289 | ||
290 | EXPORT_SYMBOL(kobject_set_name); | |
291 | ||
292 | ||
293 | /** | |
294 | * kobject_rename - change the name of an object | |
295 | * @kobj: object in question. | |
296 | * @new_name: object's new name | |
297 | */ | |
298 | ||
f3b4f3c6 | 299 | int kobject_rename(struct kobject * kobj, const char *new_name) |
1da177e4 LT |
300 | { |
301 | int error = 0; | |
302 | ||
303 | kobj = kobject_get(kobj); | |
304 | if (!kobj) | |
305 | return -EINVAL; | |
306 | error = sysfs_rename_dir(kobj, new_name); | |
307 | kobject_put(kobj); | |
308 | ||
309 | return error; | |
310 | } | |
311 | ||
312 | /** | |
313 | * kobject_del - unlink kobject from hierarchy. | |
314 | * @kobj: object. | |
315 | */ | |
316 | ||
317 | void kobject_del(struct kobject * kobj) | |
318 | { | |
1da177e4 LT |
319 | sysfs_remove_dir(kobj); |
320 | unlink(kobj); | |
321 | } | |
322 | ||
323 | /** | |
324 | * kobject_unregister - remove object from hierarchy and decrement refcount. | |
325 | * @kobj: object going away. | |
326 | */ | |
327 | ||
328 | void kobject_unregister(struct kobject * kobj) | |
329 | { | |
330 | pr_debug("kobject %s: unregistering\n",kobject_name(kobj)); | |
312c004d | 331 | kobject_uevent(kobj, KOBJ_REMOVE); |
1da177e4 LT |
332 | kobject_del(kobj); |
333 | kobject_put(kobj); | |
334 | } | |
335 | ||
336 | /** | |
337 | * kobject_get - increment refcount for object. | |
338 | * @kobj: object. | |
339 | */ | |
340 | ||
341 | struct kobject * kobject_get(struct kobject * kobj) | |
342 | { | |
343 | if (kobj) | |
344 | kref_get(&kobj->kref); | |
345 | return kobj; | |
346 | } | |
347 | ||
348 | /** | |
349 | * kobject_cleanup - free kobject resources. | |
350 | * @kobj: object. | |
351 | */ | |
352 | ||
353 | void kobject_cleanup(struct kobject * kobj) | |
354 | { | |
355 | struct kobj_type * t = get_ktype(kobj); | |
356 | struct kset * s = kobj->kset; | |
357 | struct kobject * parent = kobj->parent; | |
358 | ||
359 | pr_debug("kobject %s: cleaning up\n",kobject_name(kobj)); | |
360 | if (kobj->k_name != kobj->name) | |
361 | kfree(kobj->k_name); | |
362 | kobj->k_name = NULL; | |
363 | if (t && t->release) | |
364 | t->release(kobj); | |
365 | if (s) | |
366 | kset_put(s); | |
367 | if (parent) | |
368 | kobject_put(parent); | |
369 | } | |
370 | ||
371 | static void kobject_release(struct kref *kref) | |
372 | { | |
373 | kobject_cleanup(container_of(kref, struct kobject, kref)); | |
374 | } | |
375 | ||
376 | /** | |
377 | * kobject_put - decrement refcount for object. | |
378 | * @kobj: object. | |
379 | * | |
380 | * Decrement the refcount, and if 0, call kobject_cleanup(). | |
381 | */ | |
382 | void kobject_put(struct kobject * kobj) | |
383 | { | |
384 | if (kobj) | |
385 | kref_put(&kobj->kref, kobject_release); | |
386 | } | |
387 | ||
388 | ||
7423172a JN |
389 | static void dir_release(struct kobject *kobj) |
390 | { | |
391 | kfree(kobj); | |
392 | } | |
393 | ||
394 | static struct kobj_type dir_ktype = { | |
395 | .release = dir_release, | |
396 | .sysfs_ops = NULL, | |
397 | .default_attrs = NULL, | |
398 | }; | |
399 | ||
400 | /** | |
401 | * kobject_add_dir - add sub directory of object. | |
402 | * @parent: object in which a directory is created. | |
403 | * @name: directory name. | |
404 | * | |
405 | * Add a plain directory object as child of given object. | |
406 | */ | |
407 | struct kobject *kobject_add_dir(struct kobject *parent, const char *name) | |
408 | { | |
409 | struct kobject *k; | |
410 | ||
411 | if (!parent) | |
412 | return NULL; | |
413 | ||
414 | k = kzalloc(sizeof(*k), GFP_KERNEL); | |
415 | if (!k) | |
416 | return NULL; | |
417 | ||
418 | k->parent = parent; | |
419 | k->ktype = &dir_ktype; | |
420 | kobject_set_name(k, name); | |
421 | kobject_register(k); | |
422 | ||
423 | return k; | |
424 | } | |
7423172a | 425 | |
1da177e4 LT |
426 | /** |
427 | * kset_init - initialize a kset for use | |
428 | * @k: kset | |
429 | */ | |
430 | ||
431 | void kset_init(struct kset * k) | |
432 | { | |
433 | kobject_init(&k->kobj); | |
434 | INIT_LIST_HEAD(&k->list); | |
435 | spin_lock_init(&k->list_lock); | |
436 | } | |
437 | ||
438 | ||
439 | /** | |
440 | * kset_add - add a kset object to the hierarchy. | |
441 | * @k: kset. | |
442 | * | |
443 | * Simply, this adds the kset's embedded kobject to the | |
444 | * hierarchy. | |
445 | * We also try to make sure that the kset's embedded kobject | |
446 | * has a parent before it is added. We only care if the embedded | |
447 | * kobject is not part of a kset itself, since kobject_add() | |
448 | * assigns a parent in that case. | |
449 | * If that is the case, and the kset has a controlling subsystem, | |
450 | * then we set the kset's parent to be said subsystem. | |
451 | */ | |
452 | ||
453 | int kset_add(struct kset * k) | |
454 | { | |
455 | if (!k->kobj.parent && !k->kobj.kset && k->subsys) | |
456 | k->kobj.parent = &k->subsys->kset.kobj; | |
457 | ||
458 | return kobject_add(&k->kobj); | |
459 | } | |
460 | ||
461 | ||
462 | /** | |
463 | * kset_register - initialize and add a kset. | |
464 | * @k: kset. | |
465 | */ | |
466 | ||
467 | int kset_register(struct kset * k) | |
468 | { | |
469 | kset_init(k); | |
470 | return kset_add(k); | |
471 | } | |
472 | ||
473 | ||
474 | /** | |
475 | * kset_unregister - remove a kset. | |
476 | * @k: kset. | |
477 | */ | |
478 | ||
479 | void kset_unregister(struct kset * k) | |
480 | { | |
481 | kobject_unregister(&k->kobj); | |
482 | } | |
483 | ||
484 | ||
485 | /** | |
486 | * kset_find_obj - search for object in kset. | |
487 | * @kset: kset we're looking in. | |
488 | * @name: object's name. | |
489 | * | |
490 | * Lock kset via @kset->subsys, and iterate over @kset->list, | |
491 | * looking for a matching kobject. If matching object is found | |
492 | * take a reference and return the object. | |
493 | */ | |
494 | ||
495 | struct kobject * kset_find_obj(struct kset * kset, const char * name) | |
496 | { | |
497 | struct list_head * entry; | |
498 | struct kobject * ret = NULL; | |
499 | ||
500 | spin_lock(&kset->list_lock); | |
501 | list_for_each(entry,&kset->list) { | |
502 | struct kobject * k = to_kobj(entry); | |
503 | if (kobject_name(k) && !strcmp(kobject_name(k),name)) { | |
504 | ret = kobject_get(k); | |
505 | break; | |
506 | } | |
507 | } | |
508 | spin_unlock(&kset->list_lock); | |
509 | return ret; | |
510 | } | |
511 | ||
512 | ||
513 | void subsystem_init(struct subsystem * s) | |
514 | { | |
515 | init_rwsem(&s->rwsem); | |
516 | kset_init(&s->kset); | |
517 | } | |
518 | ||
519 | /** | |
520 | * subsystem_register - register a subsystem. | |
521 | * @s: the subsystem we're registering. | |
522 | * | |
523 | * Once we register the subsystem, we want to make sure that | |
524 | * the kset points back to this subsystem for correct usage of | |
525 | * the rwsem. | |
526 | */ | |
527 | ||
528 | int subsystem_register(struct subsystem * s) | |
529 | { | |
530 | int error; | |
531 | ||
532 | subsystem_init(s); | |
533 | pr_debug("subsystem %s: registering\n",s->kset.kobj.name); | |
534 | ||
535 | if (!(error = kset_add(&s->kset))) { | |
536 | if (!s->kset.subsys) | |
537 | s->kset.subsys = s; | |
538 | } | |
539 | return error; | |
540 | } | |
541 | ||
542 | void subsystem_unregister(struct subsystem * s) | |
543 | { | |
544 | pr_debug("subsystem %s: unregistering\n",s->kset.kobj.name); | |
545 | kset_unregister(&s->kset); | |
546 | } | |
547 | ||
548 | ||
549 | /** | |
550 | * subsystem_create_file - export sysfs attribute file. | |
551 | * @s: subsystem. | |
552 | * @a: subsystem attribute descriptor. | |
553 | */ | |
554 | ||
555 | int subsys_create_file(struct subsystem * s, struct subsys_attribute * a) | |
556 | { | |
557 | int error = 0; | |
558 | if (subsys_get(s)) { | |
559 | error = sysfs_create_file(&s->kset.kobj,&a->attr); | |
560 | subsys_put(s); | |
561 | } | |
562 | return error; | |
563 | } | |
564 | ||
565 | ||
566 | /** | |
567 | * subsystem_remove_file - remove sysfs attribute file. | |
568 | * @s: subsystem. | |
569 | * @a: attribute desciptor. | |
570 | */ | |
5b3ef14e | 571 | #if 0 |
1da177e4 LT |
572 | void subsys_remove_file(struct subsystem * s, struct subsys_attribute * a) |
573 | { | |
574 | if (subsys_get(s)) { | |
575 | sysfs_remove_file(&s->kset.kobj,&a->attr); | |
576 | subsys_put(s); | |
577 | } | |
578 | } | |
5b3ef14e | 579 | #endif /* 0 */ |
1da177e4 LT |
580 | |
581 | EXPORT_SYMBOL(kobject_init); | |
582 | EXPORT_SYMBOL(kobject_register); | |
583 | EXPORT_SYMBOL(kobject_unregister); | |
584 | EXPORT_SYMBOL(kobject_get); | |
585 | EXPORT_SYMBOL(kobject_put); | |
586 | EXPORT_SYMBOL(kobject_add); | |
587 | EXPORT_SYMBOL(kobject_del); | |
588 | ||
589 | EXPORT_SYMBOL(kset_register); | |
590 | EXPORT_SYMBOL(kset_unregister); | |
1da177e4 | 591 | |
1da177e4 LT |
592 | EXPORT_SYMBOL(subsystem_register); |
593 | EXPORT_SYMBOL(subsystem_unregister); | |
594 | EXPORT_SYMBOL(subsys_create_file); |