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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;
Burman Yan4668edc2006-12-06 20:38:51 -0800114 path = kzalloc(len, gfp_mask);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115 if (!path)
116 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700117 fill_kobj_path(kobj, path, len);
118
119 return path;
120}
Dmitry Torokhov80fc9f52006-10-11 01:43:58 -0400121EXPORT_SYMBOL_GPL(kobject_get_path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700122
123/**
124 * kobject_init - initialize object.
125 * @kobj: object in question.
126 */
127void kobject_init(struct kobject * kobj)
128{
Greg Kroah-Hartman31b9025a2007-01-18 12:23:51 -0800129 if (!kobj)
130 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131 kref_init(&kobj->kref);
132 INIT_LIST_HEAD(&kobj->entry);
NeilBrown4508a7a2006-03-20 17:53:53 +1100133 init_waitqueue_head(&kobj->poll);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700134 kobj->kset = kset_get(kobj->kset);
135}
136
137
138/**
139 * unlink - remove kobject from kset list.
140 * @kobj: kobject.
141 *
142 * Remove the kobject from the kset list and decrement
143 * its parent's refcount.
144 * This is separated out, so we can use it in both
145 * kobject_del() and kobject_add() on error.
146 */
147
148static void unlink(struct kobject * kobj)
149{
150 if (kobj->kset) {
151 spin_lock(&kobj->kset->list_lock);
152 list_del_init(&kobj->entry);
153 spin_unlock(&kobj->kset->list_lock);
154 }
155 kobject_put(kobj);
156}
157
158/**
159 * kobject_add - add an object to the hierarchy.
160 * @kobj: object.
161 */
162
163int kobject_add(struct kobject * kobj)
164{
165 int error = 0;
166 struct kobject * parent;
167
168 if (!(kobj = kobject_get(kobj)))
169 return -ENOENT;
170 if (!kobj->k_name)
171 kobj->k_name = kobj->name;
Greg Kroah-Hartmanc171fef2006-01-20 14:08:59 -0800172 if (!kobj->k_name) {
173 pr_debug("kobject attempted to be registered with no name!\n");
174 WARN_ON(1);
175 return -EINVAL;
176 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700177 parent = kobject_get(kobj->parent);
178
179 pr_debug("kobject %s: registering. parent: %s, set: %s\n",
180 kobject_name(kobj), parent ? kobject_name(parent) : "<NULL>",
181 kobj->kset ? kobj->kset->kobj.name : "<NULL>" );
182
183 if (kobj->kset) {
184 spin_lock(&kobj->kset->list_lock);
185
186 if (!parent)
187 parent = kobject_get(&kobj->kset->kobj);
188
189 list_add_tail(&kobj->entry,&kobj->kset->list);
190 spin_unlock(&kobj->kset->list_lock);
191 }
192 kobj->parent = parent;
193
194 error = create_dir(kobj);
195 if (error) {
196 /* unlink does the kobject_put() for us */
197 unlink(kobj);
198 if (parent)
199 kobject_put(parent);
Greg Kroah-Hartmandcd0da02006-03-20 13:17:13 -0800200
201 /* be noisy on error issues */
202 if (error == -EEXIST)
Greg Kroah-Hartman183bd5b2006-05-18 10:39:21 -0700203 printk("kobject_add failed for %s with -EEXIST, "
Greg Kroah-Hartmandcd0da02006-03-20 13:17:13 -0800204 "don't try to register things with the "
205 "same name in the same directory.\n",
206 kobject_name(kobj));
207 else
Greg Kroah-Hartman183bd5b2006-05-18 10:39:21 -0700208 printk("kobject_add failed for %s (%d)\n",
Greg Kroah-Hartmandcd0da02006-03-20 13:17:13 -0800209 kobject_name(kobj), error);
Greg Kroah-Hartman183bd5b2006-05-18 10:39:21 -0700210 dump_stack();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211 }
212
213 return error;
214}
215
216
217/**
218 * kobject_register - initialize and add an object.
219 * @kobj: object in question.
220 */
221
222int kobject_register(struct kobject * kobj)
223{
Greg Kroah-Hartmandcd0da02006-03-20 13:17:13 -0800224 int error = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700225 if (kobj) {
226 kobject_init(kobj);
227 error = kobject_add(kobj);
Greg Kroah-Hartmandcd0da02006-03-20 13:17:13 -0800228 if (!error)
Kay Sievers312c0042005-11-16 09:00:00 +0100229 kobject_uevent(kobj, KOBJ_ADD);
Greg Kroah-Hartmandcd0da02006-03-20 13:17:13 -0800230 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231 return error;
232}
233
234
235/**
236 * kobject_set_name - Set the name of an object
237 * @kobj: object.
Martin Waitz67be2dd2005-05-01 08:59:26 -0700238 * @fmt: format string used to build the name
Linus Torvalds1da177e2005-04-16 15:20:36 -0700239 *
240 * If strlen(name) >= KOBJ_NAME_LEN, then use a dynamically allocated
241 * string that @kobj->k_name points to. Otherwise, use the static
242 * @kobj->name array.
243 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244int kobject_set_name(struct kobject * kobj, const char * fmt, ...)
245{
246 int error = 0;
247 int limit = KOBJ_NAME_LEN;
248 int need;
249 va_list args;
250 char * name;
251
252 /*
253 * First, try the static array
254 */
255 va_start(args,fmt);
256 need = vsnprintf(kobj->name,limit,fmt,args);
257 va_end(args);
258 if (need < limit)
259 name = kobj->name;
260 else {
261 /*
262 * Need more space? Allocate it and try again
263 */
264 limit = need + 1;
265 name = kmalloc(limit,GFP_KERNEL);
266 if (!name) {
267 error = -ENOMEM;
268 goto Done;
269 }
270 va_start(args,fmt);
271 need = vsnprintf(name,limit,fmt,args);
272 va_end(args);
273
274 /* Still? Give up. */
275 if (need >= limit) {
276 kfree(name);
277 error = -EFAULT;
278 goto Done;
279 }
280 }
281
282 /* Free the old name, if necessary. */
283 if (kobj->k_name && kobj->k_name != kobj->name)
284 kfree(kobj->k_name);
285
286 /* Now, set the new name */
287 kobj->k_name = name;
288 Done:
289 return error;
290}
291
292EXPORT_SYMBOL(kobject_set_name);
293
294
295/**
296 * kobject_rename - change the name of an object
297 * @kobj: object in question.
298 * @new_name: object's new name
299 */
300
Dmitry Torokhovf3b4f3c2005-04-26 02:32:00 -0500301int kobject_rename(struct kobject * kobj, const char *new_name)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700302{
303 int error = 0;
304
305 kobj = kobject_get(kobj);
306 if (!kobj)
307 return -EINVAL;
308 error = sysfs_rename_dir(kobj, new_name);
309 kobject_put(kobj);
310
311 return error;
312}
313
314/**
Cornelia Huck8a824722006-11-20 17:07:51 +0100315 * kobject_move - move object to another parent
316 * @kobj: object in question.
317 * @new_parent: object's new parent
318 */
319
320int kobject_move(struct kobject *kobj, struct kobject *new_parent)
321{
322 int error;
323 struct kobject *old_parent;
324 const char *devpath = NULL;
325 char *devpath_string = NULL;
326 char *envp[2];
327
328 kobj = kobject_get(kobj);
329 if (!kobj)
330 return -EINVAL;
331 new_parent = kobject_get(new_parent);
332 if (!new_parent) {
333 error = -EINVAL;
334 goto out;
335 }
336 /* old object path */
337 devpath = kobject_get_path(kobj, GFP_KERNEL);
338 if (!devpath) {
339 error = -ENOMEM;
340 goto out;
341 }
342 devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
343 if (!devpath_string) {
344 error = -ENOMEM;
345 goto out;
346 }
347 sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
348 envp[0] = devpath_string;
349 envp[1] = NULL;
350 error = sysfs_move_dir(kobj, new_parent);
351 if (error)
352 goto out;
353 old_parent = kobj->parent;
354 kobj->parent = new_parent;
355 kobject_put(old_parent);
356 kobject_uevent_env(kobj, KOBJ_MOVE, envp);
357out:
358 kobject_put(kobj);
359 kfree(devpath_string);
360 kfree(devpath);
361 return error;
362}
363
364/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700365 * kobject_del - unlink kobject from hierarchy.
366 * @kobj: object.
367 */
368
369void kobject_del(struct kobject * kobj)
370{
Greg Kroah-Hartman31b9025a2007-01-18 12:23:51 -0800371 if (!kobj)
372 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700373 sysfs_remove_dir(kobj);
374 unlink(kobj);
375}
376
377/**
378 * kobject_unregister - remove object from hierarchy and decrement refcount.
379 * @kobj: object going away.
380 */
381
382void kobject_unregister(struct kobject * kobj)
383{
Greg Kroah-Hartman31b9025a2007-01-18 12:23:51 -0800384 if (!kobj)
385 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700386 pr_debug("kobject %s: unregistering\n",kobject_name(kobj));
Kay Sievers312c0042005-11-16 09:00:00 +0100387 kobject_uevent(kobj, KOBJ_REMOVE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700388 kobject_del(kobj);
389 kobject_put(kobj);
390}
391
392/**
393 * kobject_get - increment refcount for object.
394 * @kobj: object.
395 */
396
397struct kobject * kobject_get(struct kobject * kobj)
398{
399 if (kobj)
400 kref_get(&kobj->kref);
401 return kobj;
402}
403
404/**
405 * kobject_cleanup - free kobject resources.
406 * @kobj: object.
407 */
408
409void kobject_cleanup(struct kobject * kobj)
410{
411 struct kobj_type * t = get_ktype(kobj);
412 struct kset * s = kobj->kset;
413 struct kobject * parent = kobj->parent;
414
415 pr_debug("kobject %s: cleaning up\n",kobject_name(kobj));
416 if (kobj->k_name != kobj->name)
417 kfree(kobj->k_name);
418 kobj->k_name = NULL;
419 if (t && t->release)
420 t->release(kobj);
421 if (s)
422 kset_put(s);
423 if (parent)
424 kobject_put(parent);
425}
426
427static void kobject_release(struct kref *kref)
428{
429 kobject_cleanup(container_of(kref, struct kobject, kref));
430}
431
432/**
433 * kobject_put - decrement refcount for object.
434 * @kobj: object.
435 *
436 * Decrement the refcount, and if 0, call kobject_cleanup().
437 */
438void kobject_put(struct kobject * kobj)
439{
440 if (kobj)
441 kref_put(&kobj->kref, kobject_release);
442}
443
444
Jun'ichi Nomura74231722006-03-13 17:14:25 -0500445static void dir_release(struct kobject *kobj)
446{
447 kfree(kobj);
448}
449
450static struct kobj_type dir_ktype = {
451 .release = dir_release,
452 .sysfs_ops = NULL,
453 .default_attrs = NULL,
454};
455
456/**
457 * kobject_add_dir - add sub directory of object.
458 * @parent: object in which a directory is created.
459 * @name: directory name.
460 *
461 * Add a plain directory object as child of given object.
462 */
463struct kobject *kobject_add_dir(struct kobject *parent, const char *name)
464{
465 struct kobject *k;
Randy Dunlap10188012006-07-11 20:49:41 -0700466 int ret;
Jun'ichi Nomura74231722006-03-13 17:14:25 -0500467
468 if (!parent)
469 return NULL;
470
471 k = kzalloc(sizeof(*k), GFP_KERNEL);
472 if (!k)
473 return NULL;
474
475 k->parent = parent;
476 k->ktype = &dir_ktype;
477 kobject_set_name(k, name);
Randy Dunlap10188012006-07-11 20:49:41 -0700478 ret = kobject_register(k);
479 if (ret < 0) {
480 printk(KERN_WARNING "kobject_add_dir: "
481 "kobject_register error: %d\n", ret);
482 kobject_del(k);
483 return NULL;
484 }
Jun'ichi Nomura74231722006-03-13 17:14:25 -0500485
486 return k;
487}
Jun'ichi Nomura74231722006-03-13 17:14:25 -0500488
Linus Torvalds1da177e2005-04-16 15:20:36 -0700489/**
490 * kset_init - initialize a kset for use
491 * @k: kset
492 */
493
494void kset_init(struct kset * k)
495{
496 kobject_init(&k->kobj);
497 INIT_LIST_HEAD(&k->list);
498 spin_lock_init(&k->list_lock);
499}
500
501
502/**
503 * kset_add - add a kset object to the hierarchy.
504 * @k: kset.
505 *
506 * Simply, this adds the kset's embedded kobject to the
507 * hierarchy.
508 * We also try to make sure that the kset's embedded kobject
509 * has a parent before it is added. We only care if the embedded
510 * kobject is not part of a kset itself, since kobject_add()
511 * assigns a parent in that case.
512 * If that is the case, and the kset has a controlling subsystem,
513 * then we set the kset's parent to be said subsystem.
514 */
515
516int kset_add(struct kset * k)
517{
518 if (!k->kobj.parent && !k->kobj.kset && k->subsys)
519 k->kobj.parent = &k->subsys->kset.kobj;
520
521 return kobject_add(&k->kobj);
522}
523
524
525/**
526 * kset_register - initialize and add a kset.
527 * @k: kset.
528 */
529
530int kset_register(struct kset * k)
531{
Greg Kroah-Hartman31b9025a2007-01-18 12:23:51 -0800532 if (!k)
533 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700534 kset_init(k);
535 return kset_add(k);
536}
537
538
539/**
540 * kset_unregister - remove a kset.
541 * @k: kset.
542 */
543
544void kset_unregister(struct kset * k)
545{
Greg Kroah-Hartman31b9025a2007-01-18 12:23:51 -0800546 if (!k)
547 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700548 kobject_unregister(&k->kobj);
549}
550
551
552/**
553 * kset_find_obj - search for object in kset.
554 * @kset: kset we're looking in.
555 * @name: object's name.
556 *
557 * Lock kset via @kset->subsys, and iterate over @kset->list,
558 * looking for a matching kobject. If matching object is found
559 * take a reference and return the object.
560 */
561
562struct kobject * kset_find_obj(struct kset * kset, const char * name)
563{
564 struct list_head * entry;
565 struct kobject * ret = NULL;
566
567 spin_lock(&kset->list_lock);
568 list_for_each(entry,&kset->list) {
569 struct kobject * k = to_kobj(entry);
570 if (kobject_name(k) && !strcmp(kobject_name(k),name)) {
571 ret = kobject_get(k);
572 break;
573 }
574 }
575 spin_unlock(&kset->list_lock);
576 return ret;
577}
578
579
580void subsystem_init(struct subsystem * s)
581{
582 init_rwsem(&s->rwsem);
583 kset_init(&s->kset);
584}
585
586/**
587 * subsystem_register - register a subsystem.
588 * @s: the subsystem we're registering.
589 *
590 * Once we register the subsystem, we want to make sure that
591 * the kset points back to this subsystem for correct usage of
592 * the rwsem.
593 */
594
595int subsystem_register(struct subsystem * s)
596{
597 int error;
598
Greg Kroah-Hartman31b9025a2007-01-18 12:23:51 -0800599 if (!s)
600 return -EINVAL;
601
Linus Torvalds1da177e2005-04-16 15:20:36 -0700602 subsystem_init(s);
603 pr_debug("subsystem %s: registering\n",s->kset.kobj.name);
604
605 if (!(error = kset_add(&s->kset))) {
606 if (!s->kset.subsys)
607 s->kset.subsys = s;
608 }
609 return error;
610}
611
612void subsystem_unregister(struct subsystem * s)
613{
Greg Kroah-Hartman31b9025a2007-01-18 12:23:51 -0800614 if (!s)
615 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700616 pr_debug("subsystem %s: unregistering\n",s->kset.kobj.name);
617 kset_unregister(&s->kset);
618}
619
620
621/**
622 * subsystem_create_file - export sysfs attribute file.
623 * @s: subsystem.
624 * @a: subsystem attribute descriptor.
625 */
626
627int subsys_create_file(struct subsystem * s, struct subsys_attribute * a)
628{
629 int error = 0;
Greg Kroah-Hartman31b9025a2007-01-18 12:23:51 -0800630
631 if (!s || !a)
632 return -EINVAL;
633
Linus Torvalds1da177e2005-04-16 15:20:36 -0700634 if (subsys_get(s)) {
635 error = sysfs_create_file(&s->kset.kobj,&a->attr);
636 subsys_put(s);
637 }
638 return error;
639}
640
641
642/**
643 * subsystem_remove_file - remove sysfs attribute file.
644 * @s: subsystem.
645 * @a: attribute desciptor.
646 */
Adrian Bunk5b3ef142006-04-22 12:14:44 +0200647#if 0
Linus Torvalds1da177e2005-04-16 15:20:36 -0700648void subsys_remove_file(struct subsystem * s, struct subsys_attribute * a)
649{
650 if (subsys_get(s)) {
651 sysfs_remove_file(&s->kset.kobj,&a->attr);
652 subsys_put(s);
653 }
654}
Adrian Bunk5b3ef142006-04-22 12:14:44 +0200655#endif /* 0 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700656
657EXPORT_SYMBOL(kobject_init);
658EXPORT_SYMBOL(kobject_register);
659EXPORT_SYMBOL(kobject_unregister);
660EXPORT_SYMBOL(kobject_get);
661EXPORT_SYMBOL(kobject_put);
662EXPORT_SYMBOL(kobject_add);
663EXPORT_SYMBOL(kobject_del);
664
665EXPORT_SYMBOL(kset_register);
666EXPORT_SYMBOL(kset_unregister);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700667
Linus Torvalds1da177e2005-04-16 15:20:36 -0700668EXPORT_SYMBOL(subsystem_register);
669EXPORT_SYMBOL(subsystem_unregister);
670EXPORT_SYMBOL(subsys_create_file);