2 * kobject.c - library routines for handling generic kernel objects
4 * Copyright (c) 2002-2003 Patrick Mochel <mochel@osdl.org>
6 * This file is released under the GPLv2.
9 * Please see the file Documentation/kobject.txt for critical information
10 * about using the kobject interface.
13 #include <linux/kobject.h>
14 #include <linux/string.h>
15 #include <linux/module.h>
16 #include <linux/stat.h>
17 #include <linux/slab.h>
20 * populate_dir - populate directory with attributes.
21 * @kobj: object we're working on.
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.
31 static int populate_dir(struct kobject * kobj)
33 struct kobj_type * t = get_ktype(kobj);
34 struct attribute * attr;
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)))
47 static int create_dir(struct kobject * kobj)
50 if (kobject_name(kobj)) {
51 error = sysfs_create_dir(kobj);
53 if ((error = populate_dir(kobj)))
54 sysfs_remove_dir(kobj);
60 static inline struct kobject * to_kobj(struct list_head * entry)
62 return container_of(entry,struct kobject,entry);
65 static int get_kobj_path_length(struct kobject *kobj)
68 struct kobject * parent = kobj;
70 /* walk up the ancestors until we hit the one pointing to the
72 * Add 1 to strlen for leading '/' of each level.
75 length += strlen(kobject_name(parent)) + 1;
76 parent = parent->parent;
81 static void fill_kobj_path(struct kobject *kobj, char *path, int length)
83 struct kobject * parent;
86 for (parent = kobj; parent; parent = parent->parent) {
87 int cur = strlen(kobject_name(parent));
88 /* back up enough to print this name with '/' */
90 strncpy (path + length, kobject_name(parent), cur);
91 *(path + --length) = '/';
94 pr_debug("%s: path = '%s'\n",__FUNCTION__,path);
98 * kobject_get_path - generate and return the path associated with a given kobj
99 * and kset pair. The result must be freed by the caller with kfree().
101 * @kobj: kobject in question, with which to build the path
102 * @gfp_mask: the allocation type used to allocate the path
104 char *kobject_get_path(struct kobject *kobj, gfp_t gfp_mask)
109 len = get_kobj_path_length(kobj);
110 path = kmalloc(len, gfp_mask);
113 memset(path, 0x00, len);
114 fill_kobj_path(kobj, path, len);
120 * kobject_init - initialize object.
121 * @kobj: object in question.
123 void kobject_init(struct kobject * kobj)
125 kref_init(&kobj->kref);
126 INIT_LIST_HEAD(&kobj->entry);
127 kobj->kset = kset_get(kobj->kset);
132 * unlink - remove kobject from kset list.
135 * Remove the kobject from the kset list and decrement
136 * its parent's refcount.
137 * This is separated out, so we can use it in both
138 * kobject_del() and kobject_add() on error.
141 static void unlink(struct kobject * kobj)
144 spin_lock(&kobj->kset->list_lock);
145 list_del_init(&kobj->entry);
146 spin_unlock(&kobj->kset->list_lock);
152 * kobject_add - add an object to the hierarchy.
156 int kobject_add(struct kobject * kobj)
159 struct kobject * parent;
161 if (!(kobj = kobject_get(kobj)))
164 kobj->k_name = kobj->name;
166 pr_debug("kobject attempted to be registered with no name!\n");
170 parent = kobject_get(kobj->parent);
172 pr_debug("kobject %s: registering. parent: %s, set: %s\n",
173 kobject_name(kobj), parent ? kobject_name(parent) : "<NULL>",
174 kobj->kset ? kobj->kset->kobj.name : "<NULL>" );
177 spin_lock(&kobj->kset->list_lock);
180 parent = kobject_get(&kobj->kset->kobj);
182 list_add_tail(&kobj->entry,&kobj->kset->list);
183 spin_unlock(&kobj->kset->list_lock);
185 kobj->parent = parent;
187 error = create_dir(kobj);
189 /* unlink does the kobject_put() for us */
200 * kobject_register - initialize and add an object.
201 * @kobj: object in question.
204 int kobject_register(struct kobject * kobj)
209 error = kobject_add(kobj);
211 printk("kobject_register failed for %s (%d)\n",
212 kobject_name(kobj),error);
215 kobject_uevent(kobj, KOBJ_ADD);
223 * kobject_set_name - Set the name of an object
225 * @fmt: format string used to build the name
227 * If strlen(name) >= KOBJ_NAME_LEN, then use a dynamically allocated
228 * string that @kobj->k_name points to. Otherwise, use the static
231 int kobject_set_name(struct kobject * kobj, const char * fmt, ...)
234 int limit = KOBJ_NAME_LEN;
240 * First, try the static array
243 need = vsnprintf(kobj->name,limit,fmt,args);
249 * Need more space? Allocate it and try again
252 name = kmalloc(limit,GFP_KERNEL);
258 need = vsnprintf(name,limit,fmt,args);
261 /* Still? Give up. */
269 /* Free the old name, if necessary. */
270 if (kobj->k_name && kobj->k_name != kobj->name)
273 /* Now, set the new name */
279 EXPORT_SYMBOL(kobject_set_name);
283 * kobject_rename - change the name of an object
284 * @kobj: object in question.
285 * @new_name: object's new name
288 int kobject_rename(struct kobject * kobj, const char *new_name)
292 kobj = kobject_get(kobj);
295 error = sysfs_rename_dir(kobj, new_name);
302 * kobject_del - unlink kobject from hierarchy.
306 void kobject_del(struct kobject * kobj)
308 sysfs_remove_dir(kobj);
313 * kobject_unregister - remove object from hierarchy and decrement refcount.
314 * @kobj: object going away.
317 void kobject_unregister(struct kobject * kobj)
319 pr_debug("kobject %s: unregistering\n",kobject_name(kobj));
320 kobject_uevent(kobj, KOBJ_REMOVE);
326 * kobject_get - increment refcount for object.
330 struct kobject * kobject_get(struct kobject * kobj)
333 kref_get(&kobj->kref);
338 * kobject_cleanup - free kobject resources.
342 void kobject_cleanup(struct kobject * kobj)
344 struct kobj_type * t = get_ktype(kobj);
345 struct kset * s = kobj->kset;
346 struct kobject * parent = kobj->parent;
348 pr_debug("kobject %s: cleaning up\n",kobject_name(kobj));
349 if (kobj->k_name != kobj->name)
360 static void kobject_release(struct kref *kref)
362 kobject_cleanup(container_of(kref, struct kobject, kref));
366 * kobject_put - decrement refcount for object.
369 * Decrement the refcount, and if 0, call kobject_cleanup().
371 void kobject_put(struct kobject * kobj)
374 kref_put(&kobj->kref, kobject_release);
379 * kset_init - initialize a kset for use
383 void kset_init(struct kset * k)
385 kobject_init(&k->kobj);
386 INIT_LIST_HEAD(&k->list);
387 spin_lock_init(&k->list_lock);
392 * kset_add - add a kset object to the hierarchy.
395 * Simply, this adds the kset's embedded kobject to the
397 * We also try to make sure that the kset's embedded kobject
398 * has a parent before it is added. We only care if the embedded
399 * kobject is not part of a kset itself, since kobject_add()
400 * assigns a parent in that case.
401 * If that is the case, and the kset has a controlling subsystem,
402 * then we set the kset's parent to be said subsystem.
405 int kset_add(struct kset * k)
407 if (!k->kobj.parent && !k->kobj.kset && k->subsys)
408 k->kobj.parent = &k->subsys->kset.kobj;
410 return kobject_add(&k->kobj);
415 * kset_register - initialize and add a kset.
419 int kset_register(struct kset * k)
427 * kset_unregister - remove a kset.
431 void kset_unregister(struct kset * k)
433 kobject_unregister(&k->kobj);
438 * kset_find_obj - search for object in kset.
439 * @kset: kset we're looking in.
440 * @name: object's name.
442 * Lock kset via @kset->subsys, and iterate over @kset->list,
443 * looking for a matching kobject. If matching object is found
444 * take a reference and return the object.
447 struct kobject * kset_find_obj(struct kset * kset, const char * name)
449 struct list_head * entry;
450 struct kobject * ret = NULL;
452 spin_lock(&kset->list_lock);
453 list_for_each(entry,&kset->list) {
454 struct kobject * k = to_kobj(entry);
455 if (kobject_name(k) && !strcmp(kobject_name(k),name)) {
456 ret = kobject_get(k);
460 spin_unlock(&kset->list_lock);
465 void subsystem_init(struct subsystem * s)
467 init_rwsem(&s->rwsem);
472 * subsystem_register - register a subsystem.
473 * @s: the subsystem we're registering.
475 * Once we register the subsystem, we want to make sure that
476 * the kset points back to this subsystem for correct usage of
480 int subsystem_register(struct subsystem * s)
485 pr_debug("subsystem %s: registering\n",s->kset.kobj.name);
487 if (!(error = kset_add(&s->kset))) {
494 void subsystem_unregister(struct subsystem * s)
496 pr_debug("subsystem %s: unregistering\n",s->kset.kobj.name);
497 kset_unregister(&s->kset);
502 * subsystem_create_file - export sysfs attribute file.
504 * @a: subsystem attribute descriptor.
507 int subsys_create_file(struct subsystem * s, struct subsys_attribute * a)
511 error = sysfs_create_file(&s->kset.kobj,&a->attr);
519 * subsystem_remove_file - remove sysfs attribute file.
521 * @a: attribute desciptor.
524 void subsys_remove_file(struct subsystem * s, struct subsys_attribute * a)
527 sysfs_remove_file(&s->kset.kobj,&a->attr);
532 EXPORT_SYMBOL(kobject_init);
533 EXPORT_SYMBOL(kobject_register);
534 EXPORT_SYMBOL(kobject_unregister);
535 EXPORT_SYMBOL(kobject_get);
536 EXPORT_SYMBOL(kobject_put);
537 EXPORT_SYMBOL(kobject_add);
538 EXPORT_SYMBOL(kobject_del);
540 EXPORT_SYMBOL(kset_register);
541 EXPORT_SYMBOL(kset_unregister);
542 EXPORT_SYMBOL(kset_find_obj);
544 EXPORT_SYMBOL(subsystem_init);
545 EXPORT_SYMBOL(subsystem_register);
546 EXPORT_SYMBOL(subsystem_unregister);
547 EXPORT_SYMBOL(subsys_create_file);
548 EXPORT_SYMBOL(subsys_remove_file);