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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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>
Tim Schmielau4e57b682005-10-30 15:03:48 -080017#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070018
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
31static 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
47static 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
60static inline struct kobject * to_kobj(struct list_head * entry)
61{
62 return container_of(entry,struct kobject,entry);
63}
64
65static 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 {
Chuck Ebbertb365b3d2006-01-12 20:02:00 -050075 if (kobject_name(parent) == NULL)
76 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -070077 length += strlen(kobject_name(parent)) + 1;
78 parent = parent->parent;
79 } while (parent);
80 return length;
81}
82
83static 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 */
Al Virofd4f2df2005-10-21 03:18:50 -0400106char *kobject_get_path(struct kobject *kobj, gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107{
108 char *path;
109 int len;
110
111 len = get_kobj_path_length(kobj);
Chuck Ebbertb365b3d2006-01-12 20:02:00 -0500112 if (len == 0)
113 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114 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 */
127void kobject_init(struct kobject * kobj)
128{
129 kref_init(&kobj->kref);
130 INIT_LIST_HEAD(&kobj->entry);
NeilBrown4508a7a2006-03-20 17:53:53 +1100131 init_waitqueue_head(&kobj->poll);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132 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
146static 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
161int 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;
Greg Kroah-Hartmanc171fef2006-01-20 14:08:59 -0800170 if (!kobj->k_name) {
171 pr_debug("kobject attempted to be registered with no name!\n");
172 WARN_ON(1);
173 return -EINVAL;
174 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175 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);
Greg Kroah-Hartmandcd0da02006-03-20 13:17:13 -0800198
199 /* be noisy on error issues */
200 if (error == -EEXIST)
201 printk("kobject_add failed for %s with -EEXIST, "
202 "don't try to register things with the "
203 "same name in the same directory.\n",
204 kobject_name(kobj));
205 else
206 printk("kobject_add failed for %s (%d)\n",
207 kobject_name(kobj), error);
208 dump_stack();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209 }
210
211 return error;
212}
213
214
215/**
216 * kobject_register - initialize and add an object.
217 * @kobj: object in question.
218 */
219
220int kobject_register(struct kobject * kobj)
221{
Greg Kroah-Hartmandcd0da02006-03-20 13:17:13 -0800222 int error = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223 if (kobj) {
224 kobject_init(kobj);
225 error = kobject_add(kobj);
Greg Kroah-Hartmandcd0da02006-03-20 13:17:13 -0800226 if (!error)
Kay Sievers312c0042005-11-16 09:00:00 +0100227 kobject_uevent(kobj, KOBJ_ADD);
Greg Kroah-Hartmandcd0da02006-03-20 13:17:13 -0800228 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229 return error;
230}
231
232
233/**
234 * kobject_set_name - Set the name of an object
235 * @kobj: object.
Martin Waitz67be2dd2005-05-01 08:59:26 -0700236 * @fmt: format string used to build the name
Linus Torvalds1da177e2005-04-16 15:20:36 -0700237 *
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 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700242int 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
290EXPORT_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
Dmitry Torokhovf3b4f3c2005-04-26 02:32:00 -0500299int kobject_rename(struct kobject * kobj, const char *new_name)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700300{
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
317void kobject_del(struct kobject * kobj)
318{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700319 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
328void kobject_unregister(struct kobject * kobj)
329{
330 pr_debug("kobject %s: unregistering\n",kobject_name(kobj));
Kay Sievers312c0042005-11-16 09:00:00 +0100331 kobject_uevent(kobj, KOBJ_REMOVE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700332 kobject_del(kobj);
333 kobject_put(kobj);
334}
335
336/**
337 * kobject_get - increment refcount for object.
338 * @kobj: object.
339 */
340
341struct 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
353void 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
371static 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 */
382void kobject_put(struct kobject * kobj)
383{
384 if (kobj)
385 kref_put(&kobj->kref, kobject_release);
386}
387
388
Jun'ichi Nomura74231722006-03-13 17:14:25 -0500389static void dir_release(struct kobject *kobj)
390{
391 kfree(kobj);
392}
393
394static 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 */
407struct 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}
425EXPORT_SYMBOL_GPL(kobject_add_dir);
426
Linus Torvalds1da177e2005-04-16 15:20:36 -0700427/**
428 * kset_init - initialize a kset for use
429 * @k: kset
430 */
431
432void kset_init(struct kset * k)
433{
434 kobject_init(&k->kobj);
435 INIT_LIST_HEAD(&k->list);
436 spin_lock_init(&k->list_lock);
437}
438
439
440/**
441 * kset_add - add a kset object to the hierarchy.
442 * @k: kset.
443 *
444 * Simply, this adds the kset's embedded kobject to the
445 * hierarchy.
446 * We also try to make sure that the kset's embedded kobject
447 * has a parent before it is added. We only care if the embedded
448 * kobject is not part of a kset itself, since kobject_add()
449 * assigns a parent in that case.
450 * If that is the case, and the kset has a controlling subsystem,
451 * then we set the kset's parent to be said subsystem.
452 */
453
454int kset_add(struct kset * k)
455{
456 if (!k->kobj.parent && !k->kobj.kset && k->subsys)
457 k->kobj.parent = &k->subsys->kset.kobj;
458
459 return kobject_add(&k->kobj);
460}
461
462
463/**
464 * kset_register - initialize and add a kset.
465 * @k: kset.
466 */
467
468int kset_register(struct kset * k)
469{
470 kset_init(k);
471 return kset_add(k);
472}
473
474
475/**
476 * kset_unregister - remove a kset.
477 * @k: kset.
478 */
479
480void kset_unregister(struct kset * k)
481{
482 kobject_unregister(&k->kobj);
483}
484
485
486/**
487 * kset_find_obj - search for object in kset.
488 * @kset: kset we're looking in.
489 * @name: object's name.
490 *
491 * Lock kset via @kset->subsys, and iterate over @kset->list,
492 * looking for a matching kobject. If matching object is found
493 * take a reference and return the object.
494 */
495
496struct kobject * kset_find_obj(struct kset * kset, const char * name)
497{
498 struct list_head * entry;
499 struct kobject * ret = NULL;
500
501 spin_lock(&kset->list_lock);
502 list_for_each(entry,&kset->list) {
503 struct kobject * k = to_kobj(entry);
504 if (kobject_name(k) && !strcmp(kobject_name(k),name)) {
505 ret = kobject_get(k);
506 break;
507 }
508 }
509 spin_unlock(&kset->list_lock);
510 return ret;
511}
512
513
514void subsystem_init(struct subsystem * s)
515{
516 init_rwsem(&s->rwsem);
517 kset_init(&s->kset);
518}
519
520/**
521 * subsystem_register - register a subsystem.
522 * @s: the subsystem we're registering.
523 *
524 * Once we register the subsystem, we want to make sure that
525 * the kset points back to this subsystem for correct usage of
526 * the rwsem.
527 */
528
529int subsystem_register(struct subsystem * s)
530{
531 int error;
532
533 subsystem_init(s);
534 pr_debug("subsystem %s: registering\n",s->kset.kobj.name);
535
536 if (!(error = kset_add(&s->kset))) {
537 if (!s->kset.subsys)
538 s->kset.subsys = s;
539 }
540 return error;
541}
542
543void subsystem_unregister(struct subsystem * s)
544{
545 pr_debug("subsystem %s: unregistering\n",s->kset.kobj.name);
546 kset_unregister(&s->kset);
547}
548
549
550/**
551 * subsystem_create_file - export sysfs attribute file.
552 * @s: subsystem.
553 * @a: subsystem attribute descriptor.
554 */
555
556int subsys_create_file(struct subsystem * s, struct subsys_attribute * a)
557{
558 int error = 0;
559 if (subsys_get(s)) {
560 error = sysfs_create_file(&s->kset.kobj,&a->attr);
561 subsys_put(s);
562 }
563 return error;
564}
565
566
567/**
568 * subsystem_remove_file - remove sysfs attribute file.
569 * @s: subsystem.
570 * @a: attribute desciptor.
571 */
572
573void subsys_remove_file(struct subsystem * s, struct subsys_attribute * a)
574{
575 if (subsys_get(s)) {
576 sysfs_remove_file(&s->kset.kobj,&a->attr);
577 subsys_put(s);
578 }
579}
580
581EXPORT_SYMBOL(kobject_init);
582EXPORT_SYMBOL(kobject_register);
583EXPORT_SYMBOL(kobject_unregister);
584EXPORT_SYMBOL(kobject_get);
585EXPORT_SYMBOL(kobject_put);
586EXPORT_SYMBOL(kobject_add);
587EXPORT_SYMBOL(kobject_del);
588
589EXPORT_SYMBOL(kset_register);
590EXPORT_SYMBOL(kset_unregister);
591EXPORT_SYMBOL(kset_find_obj);
592
593EXPORT_SYMBOL(subsystem_init);
594EXPORT_SYMBOL(subsystem_register);
595EXPORT_SYMBOL(subsystem_unregister);
596EXPORT_SYMBOL(subsys_create_file);
597EXPORT_SYMBOL(subsys_remove_file);