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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 | } | |
80fc9f53 | 122 | EXPORT_SYMBOL_GPL(kobject_get_path); |
1da177e4 LT |
123 | |
124 | /** | |
125 | * kobject_init - initialize object. | |
126 | * @kobj: object in question. | |
127 | */ | |
128 | void kobject_init(struct kobject * kobj) | |
129 | { | |
130 | kref_init(&kobj->kref); | |
131 | INIT_LIST_HEAD(&kobj->entry); | |
4508a7a7 | 132 | init_waitqueue_head(&kobj->poll); |
1da177e4 LT |
133 | kobj->kset = kset_get(kobj->kset); |
134 | } | |
135 | ||
136 | ||
137 | /** | |
138 | * unlink - remove kobject from kset list. | |
139 | * @kobj: kobject. | |
140 | * | |
141 | * Remove the kobject from the kset list and decrement | |
142 | * its parent's refcount. | |
143 | * This is separated out, so we can use it in both | |
144 | * kobject_del() and kobject_add() on error. | |
145 | */ | |
146 | ||
147 | static void unlink(struct kobject * kobj) | |
148 | { | |
149 | if (kobj->kset) { | |
150 | spin_lock(&kobj->kset->list_lock); | |
151 | list_del_init(&kobj->entry); | |
152 | spin_unlock(&kobj->kset->list_lock); | |
153 | } | |
154 | kobject_put(kobj); | |
155 | } | |
156 | ||
157 | /** | |
158 | * kobject_add - add an object to the hierarchy. | |
159 | * @kobj: object. | |
160 | */ | |
161 | ||
162 | int kobject_add(struct kobject * kobj) | |
163 | { | |
164 | int error = 0; | |
165 | struct kobject * parent; | |
166 | ||
167 | if (!(kobj = kobject_get(kobj))) | |
168 | return -ENOENT; | |
169 | if (!kobj->k_name) | |
170 | kobj->k_name = kobj->name; | |
c171fef5 GKH |
171 | if (!kobj->k_name) { |
172 | pr_debug("kobject attempted to be registered with no name!\n"); | |
173 | WARN_ON(1); | |
174 | return -EINVAL; | |
175 | } | |
1da177e4 LT |
176 | parent = kobject_get(kobj->parent); |
177 | ||
178 | pr_debug("kobject %s: registering. parent: %s, set: %s\n", | |
179 | kobject_name(kobj), parent ? kobject_name(parent) : "<NULL>", | |
180 | kobj->kset ? kobj->kset->kobj.name : "<NULL>" ); | |
181 | ||
182 | if (kobj->kset) { | |
183 | spin_lock(&kobj->kset->list_lock); | |
184 | ||
185 | if (!parent) | |
186 | parent = kobject_get(&kobj->kset->kobj); | |
187 | ||
188 | list_add_tail(&kobj->entry,&kobj->kset->list); | |
189 | spin_unlock(&kobj->kset->list_lock); | |
190 | } | |
191 | kobj->parent = parent; | |
192 | ||
193 | error = create_dir(kobj); | |
194 | if (error) { | |
195 | /* unlink does the kobject_put() for us */ | |
196 | unlink(kobj); | |
197 | if (parent) | |
198 | kobject_put(parent); | |
dcd0da00 GKH |
199 | |
200 | /* be noisy on error issues */ | |
201 | if (error == -EEXIST) | |
183bd5b3 | 202 | printk("kobject_add failed for %s with -EEXIST, " |
dcd0da00 GKH |
203 | "don't try to register things with the " |
204 | "same name in the same directory.\n", | |
205 | kobject_name(kobj)); | |
206 | else | |
183bd5b3 | 207 | printk("kobject_add failed for %s (%d)\n", |
dcd0da00 | 208 | kobject_name(kobj), error); |
183bd5b3 | 209 | dump_stack(); |
1da177e4 LT |
210 | } |
211 | ||
212 | return error; | |
213 | } | |
214 | ||
215 | ||
216 | /** | |
217 | * kobject_register - initialize and add an object. | |
218 | * @kobj: object in question. | |
219 | */ | |
220 | ||
221 | int kobject_register(struct kobject * kobj) | |
222 | { | |
dcd0da00 | 223 | int error = -EINVAL; |
1da177e4 LT |
224 | if (kobj) { |
225 | kobject_init(kobj); | |
226 | error = kobject_add(kobj); | |
dcd0da00 | 227 | if (!error) |
312c004d | 228 | kobject_uevent(kobj, KOBJ_ADD); |
dcd0da00 | 229 | } |
1da177e4 LT |
230 | return error; |
231 | } | |
232 | ||
233 | ||
234 | /** | |
235 | * kobject_set_name - Set the name of an object | |
236 | * @kobj: object. | |
67be2dd1 | 237 | * @fmt: format string used to build the name |
1da177e4 LT |
238 | * |
239 | * If strlen(name) >= KOBJ_NAME_LEN, then use a dynamically allocated | |
240 | * string that @kobj->k_name points to. Otherwise, use the static | |
241 | * @kobj->name array. | |
242 | */ | |
1da177e4 LT |
243 | int kobject_set_name(struct kobject * kobj, const char * fmt, ...) |
244 | { | |
245 | int error = 0; | |
246 | int limit = KOBJ_NAME_LEN; | |
247 | int need; | |
248 | va_list args; | |
249 | char * name; | |
250 | ||
251 | /* | |
252 | * First, try the static array | |
253 | */ | |
254 | va_start(args,fmt); | |
255 | need = vsnprintf(kobj->name,limit,fmt,args); | |
256 | va_end(args); | |
257 | if (need < limit) | |
258 | name = kobj->name; | |
259 | else { | |
260 | /* | |
261 | * Need more space? Allocate it and try again | |
262 | */ | |
263 | limit = need + 1; | |
264 | name = kmalloc(limit,GFP_KERNEL); | |
265 | if (!name) { | |
266 | error = -ENOMEM; | |
267 | goto Done; | |
268 | } | |
269 | va_start(args,fmt); | |
270 | need = vsnprintf(name,limit,fmt,args); | |
271 | va_end(args); | |
272 | ||
273 | /* Still? Give up. */ | |
274 | if (need >= limit) { | |
275 | kfree(name); | |
276 | error = -EFAULT; | |
277 | goto Done; | |
278 | } | |
279 | } | |
280 | ||
281 | /* Free the old name, if necessary. */ | |
282 | if (kobj->k_name && kobj->k_name != kobj->name) | |
283 | kfree(kobj->k_name); | |
284 | ||
285 | /* Now, set the new name */ | |
286 | kobj->k_name = name; | |
287 | Done: | |
288 | return error; | |
289 | } | |
290 | ||
291 | EXPORT_SYMBOL(kobject_set_name); | |
292 | ||
293 | ||
294 | /** | |
295 | * kobject_rename - change the name of an object | |
296 | * @kobj: object in question. | |
297 | * @new_name: object's new name | |
298 | */ | |
299 | ||
f3b4f3c6 | 300 | int kobject_rename(struct kobject * kobj, const char *new_name) |
1da177e4 LT |
301 | { |
302 | int error = 0; | |
303 | ||
304 | kobj = kobject_get(kobj); | |
305 | if (!kobj) | |
306 | return -EINVAL; | |
307 | error = sysfs_rename_dir(kobj, new_name); | |
308 | kobject_put(kobj); | |
309 | ||
310 | return error; | |
311 | } | |
312 | ||
8a82472f CH |
313 | /** |
314 | * kobject_move - move object to another parent | |
315 | * @kobj: object in question. | |
316 | * @new_parent: object's new parent | |
317 | */ | |
318 | ||
319 | int kobject_move(struct kobject *kobj, struct kobject *new_parent) | |
320 | { | |
321 | int error; | |
322 | struct kobject *old_parent; | |
323 | const char *devpath = NULL; | |
324 | char *devpath_string = NULL; | |
325 | char *envp[2]; | |
326 | ||
327 | kobj = kobject_get(kobj); | |
328 | if (!kobj) | |
329 | return -EINVAL; | |
330 | new_parent = kobject_get(new_parent); | |
331 | if (!new_parent) { | |
332 | error = -EINVAL; | |
333 | goto out; | |
334 | } | |
335 | /* old object path */ | |
336 | devpath = kobject_get_path(kobj, GFP_KERNEL); | |
337 | if (!devpath) { | |
338 | error = -ENOMEM; | |
339 | goto out; | |
340 | } | |
341 | devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL); | |
342 | if (!devpath_string) { | |
343 | error = -ENOMEM; | |
344 | goto out; | |
345 | } | |
346 | sprintf(devpath_string, "DEVPATH_OLD=%s", devpath); | |
347 | envp[0] = devpath_string; | |
348 | envp[1] = NULL; | |
349 | error = sysfs_move_dir(kobj, new_parent); | |
350 | if (error) | |
351 | goto out; | |
352 | old_parent = kobj->parent; | |
353 | kobj->parent = new_parent; | |
354 | kobject_put(old_parent); | |
355 | kobject_uevent_env(kobj, KOBJ_MOVE, envp); | |
356 | out: | |
357 | kobject_put(kobj); | |
358 | kfree(devpath_string); | |
359 | kfree(devpath); | |
360 | return error; | |
361 | } | |
362 | ||
1da177e4 LT |
363 | /** |
364 | * kobject_del - unlink kobject from hierarchy. | |
365 | * @kobj: object. | |
366 | */ | |
367 | ||
368 | void kobject_del(struct kobject * kobj) | |
369 | { | |
1da177e4 LT |
370 | sysfs_remove_dir(kobj); |
371 | unlink(kobj); | |
372 | } | |
373 | ||
374 | /** | |
375 | * kobject_unregister - remove object from hierarchy and decrement refcount. | |
376 | * @kobj: object going away. | |
377 | */ | |
378 | ||
379 | void kobject_unregister(struct kobject * kobj) | |
380 | { | |
381 | pr_debug("kobject %s: unregistering\n",kobject_name(kobj)); | |
312c004d | 382 | kobject_uevent(kobj, KOBJ_REMOVE); |
1da177e4 LT |
383 | kobject_del(kobj); |
384 | kobject_put(kobj); | |
385 | } | |
386 | ||
387 | /** | |
388 | * kobject_get - increment refcount for object. | |
389 | * @kobj: object. | |
390 | */ | |
391 | ||
392 | struct kobject * kobject_get(struct kobject * kobj) | |
393 | { | |
394 | if (kobj) | |
395 | kref_get(&kobj->kref); | |
396 | return kobj; | |
397 | } | |
398 | ||
399 | /** | |
400 | * kobject_cleanup - free kobject resources. | |
401 | * @kobj: object. | |
402 | */ | |
403 | ||
404 | void kobject_cleanup(struct kobject * kobj) | |
405 | { | |
406 | struct kobj_type * t = get_ktype(kobj); | |
407 | struct kset * s = kobj->kset; | |
408 | struct kobject * parent = kobj->parent; | |
409 | ||
410 | pr_debug("kobject %s: cleaning up\n",kobject_name(kobj)); | |
411 | if (kobj->k_name != kobj->name) | |
412 | kfree(kobj->k_name); | |
413 | kobj->k_name = NULL; | |
414 | if (t && t->release) | |
415 | t->release(kobj); | |
416 | if (s) | |
417 | kset_put(s); | |
418 | if (parent) | |
419 | kobject_put(parent); | |
420 | } | |
421 | ||
422 | static void kobject_release(struct kref *kref) | |
423 | { | |
424 | kobject_cleanup(container_of(kref, struct kobject, kref)); | |
425 | } | |
426 | ||
427 | /** | |
428 | * kobject_put - decrement refcount for object. | |
429 | * @kobj: object. | |
430 | * | |
431 | * Decrement the refcount, and if 0, call kobject_cleanup(). | |
432 | */ | |
433 | void kobject_put(struct kobject * kobj) | |
434 | { | |
435 | if (kobj) | |
436 | kref_put(&kobj->kref, kobject_release); | |
437 | } | |
438 | ||
439 | ||
7423172a JN |
440 | static void dir_release(struct kobject *kobj) |
441 | { | |
442 | kfree(kobj); | |
443 | } | |
444 | ||
445 | static struct kobj_type dir_ktype = { | |
446 | .release = dir_release, | |
447 | .sysfs_ops = NULL, | |
448 | .default_attrs = NULL, | |
449 | }; | |
450 | ||
451 | /** | |
452 | * kobject_add_dir - add sub directory of object. | |
453 | * @parent: object in which a directory is created. | |
454 | * @name: directory name. | |
455 | * | |
456 | * Add a plain directory object as child of given object. | |
457 | */ | |
458 | struct kobject *kobject_add_dir(struct kobject *parent, const char *name) | |
459 | { | |
460 | struct kobject *k; | |
10188012 | 461 | int ret; |
7423172a JN |
462 | |
463 | if (!parent) | |
464 | return NULL; | |
465 | ||
466 | k = kzalloc(sizeof(*k), GFP_KERNEL); | |
467 | if (!k) | |
468 | return NULL; | |
469 | ||
470 | k->parent = parent; | |
471 | k->ktype = &dir_ktype; | |
472 | kobject_set_name(k, name); | |
10188012 RD |
473 | ret = kobject_register(k); |
474 | if (ret < 0) { | |
475 | printk(KERN_WARNING "kobject_add_dir: " | |
476 | "kobject_register error: %d\n", ret); | |
477 | kobject_del(k); | |
478 | return NULL; | |
479 | } | |
7423172a JN |
480 | |
481 | return k; | |
482 | } | |
7423172a | 483 | |
1da177e4 LT |
484 | /** |
485 | * kset_init - initialize a kset for use | |
486 | * @k: kset | |
487 | */ | |
488 | ||
489 | void kset_init(struct kset * k) | |
490 | { | |
491 | kobject_init(&k->kobj); | |
492 | INIT_LIST_HEAD(&k->list); | |
493 | spin_lock_init(&k->list_lock); | |
494 | } | |
495 | ||
496 | ||
497 | /** | |
498 | * kset_add - add a kset object to the hierarchy. | |
499 | * @k: kset. | |
500 | * | |
501 | * Simply, this adds the kset's embedded kobject to the | |
502 | * hierarchy. | |
503 | * We also try to make sure that the kset's embedded kobject | |
504 | * has a parent before it is added. We only care if the embedded | |
505 | * kobject is not part of a kset itself, since kobject_add() | |
506 | * assigns a parent in that case. | |
507 | * If that is the case, and the kset has a controlling subsystem, | |
508 | * then we set the kset's parent to be said subsystem. | |
509 | */ | |
510 | ||
511 | int kset_add(struct kset * k) | |
512 | { | |
513 | if (!k->kobj.parent && !k->kobj.kset && k->subsys) | |
514 | k->kobj.parent = &k->subsys->kset.kobj; | |
515 | ||
516 | return kobject_add(&k->kobj); | |
517 | } | |
518 | ||
519 | ||
520 | /** | |
521 | * kset_register - initialize and add a kset. | |
522 | * @k: kset. | |
523 | */ | |
524 | ||
525 | int kset_register(struct kset * k) | |
526 | { | |
527 | kset_init(k); | |
528 | return kset_add(k); | |
529 | } | |
530 | ||
531 | ||
532 | /** | |
533 | * kset_unregister - remove a kset. | |
534 | * @k: kset. | |
535 | */ | |
536 | ||
537 | void kset_unregister(struct kset * k) | |
538 | { | |
539 | kobject_unregister(&k->kobj); | |
540 | } | |
541 | ||
542 | ||
543 | /** | |
544 | * kset_find_obj - search for object in kset. | |
545 | * @kset: kset we're looking in. | |
546 | * @name: object's name. | |
547 | * | |
548 | * Lock kset via @kset->subsys, and iterate over @kset->list, | |
549 | * looking for a matching kobject. If matching object is found | |
550 | * take a reference and return the object. | |
551 | */ | |
552 | ||
553 | struct kobject * kset_find_obj(struct kset * kset, const char * name) | |
554 | { | |
555 | struct list_head * entry; | |
556 | struct kobject * ret = NULL; | |
557 | ||
558 | spin_lock(&kset->list_lock); | |
559 | list_for_each(entry,&kset->list) { | |
560 | struct kobject * k = to_kobj(entry); | |
561 | if (kobject_name(k) && !strcmp(kobject_name(k),name)) { | |
562 | ret = kobject_get(k); | |
563 | break; | |
564 | } | |
565 | } | |
566 | spin_unlock(&kset->list_lock); | |
567 | return ret; | |
568 | } | |
569 | ||
570 | ||
571 | void subsystem_init(struct subsystem * s) | |
572 | { | |
573 | init_rwsem(&s->rwsem); | |
574 | kset_init(&s->kset); | |
575 | } | |
576 | ||
577 | /** | |
578 | * subsystem_register - register a subsystem. | |
579 | * @s: the subsystem we're registering. | |
580 | * | |
581 | * Once we register the subsystem, we want to make sure that | |
582 | * the kset points back to this subsystem for correct usage of | |
583 | * the rwsem. | |
584 | */ | |
585 | ||
586 | int subsystem_register(struct subsystem * s) | |
587 | { | |
588 | int error; | |
589 | ||
590 | subsystem_init(s); | |
591 | pr_debug("subsystem %s: registering\n",s->kset.kobj.name); | |
592 | ||
593 | if (!(error = kset_add(&s->kset))) { | |
594 | if (!s->kset.subsys) | |
595 | s->kset.subsys = s; | |
596 | } | |
597 | return error; | |
598 | } | |
599 | ||
600 | void subsystem_unregister(struct subsystem * s) | |
601 | { | |
602 | pr_debug("subsystem %s: unregistering\n",s->kset.kobj.name); | |
603 | kset_unregister(&s->kset); | |
604 | } | |
605 | ||
606 | ||
607 | /** | |
608 | * subsystem_create_file - export sysfs attribute file. | |
609 | * @s: subsystem. | |
610 | * @a: subsystem attribute descriptor. | |
611 | */ | |
612 | ||
613 | int subsys_create_file(struct subsystem * s, struct subsys_attribute * a) | |
614 | { | |
615 | int error = 0; | |
616 | if (subsys_get(s)) { | |
617 | error = sysfs_create_file(&s->kset.kobj,&a->attr); | |
618 | subsys_put(s); | |
619 | } | |
620 | return error; | |
621 | } | |
622 | ||
623 | ||
624 | /** | |
625 | * subsystem_remove_file - remove sysfs attribute file. | |
626 | * @s: subsystem. | |
627 | * @a: attribute desciptor. | |
628 | */ | |
5b3ef14e | 629 | #if 0 |
1da177e4 LT |
630 | void subsys_remove_file(struct subsystem * s, struct subsys_attribute * a) |
631 | { | |
632 | if (subsys_get(s)) { | |
633 | sysfs_remove_file(&s->kset.kobj,&a->attr); | |
634 | subsys_put(s); | |
635 | } | |
636 | } | |
5b3ef14e | 637 | #endif /* 0 */ |
1da177e4 LT |
638 | |
639 | EXPORT_SYMBOL(kobject_init); | |
640 | EXPORT_SYMBOL(kobject_register); | |
641 | EXPORT_SYMBOL(kobject_unregister); | |
642 | EXPORT_SYMBOL(kobject_get); | |
643 | EXPORT_SYMBOL(kobject_put); | |
644 | EXPORT_SYMBOL(kobject_add); | |
645 | EXPORT_SYMBOL(kobject_del); | |
646 | ||
647 | EXPORT_SYMBOL(kset_register); | |
648 | EXPORT_SYMBOL(kset_unregister); | |
1da177e4 | 649 | |
1da177e4 LT |
650 | EXPORT_SYMBOL(subsystem_register); |
651 | EXPORT_SYMBOL(subsystem_unregister); | |
652 | EXPORT_SYMBOL(subsys_create_file); |