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>
19 * populate_dir - populate directory with attributes.
20 * @kobj: object we're working on.
22 * Most subsystems have a set of default attributes that
23 * are associated with an object that registers with them.
24 * This is a helper called during object registration that
25 * loops through the default attributes of the subsystem
26 * and creates attributes files for them in sysfs.
30 static int populate_dir(struct kobject * kobj)
32 struct kobj_type * t = get_ktype(kobj);
33 struct attribute * attr;
37 if (t && t->default_attrs) {
38 for (i = 0; (attr = t->default_attrs[i]) != NULL; i++) {
39 if ((error = sysfs_create_file(kobj,attr)))
46 static int create_dir(struct kobject * kobj)
49 if (kobject_name(kobj)) {
50 error = sysfs_create_dir(kobj);
52 if ((error = populate_dir(kobj)))
53 sysfs_remove_dir(kobj);
59 static inline struct kobject * to_kobj(struct list_head * entry)
61 return container_of(entry,struct kobject,entry);
64 static int get_kobj_path_length(struct kobject *kobj)
67 struct kobject * parent = kobj;
69 /* walk up the ancestors until we hit the one pointing to the
71 * Add 1 to strlen for leading '/' of each level.
74 length += strlen(kobject_name(parent)) + 1;
75 parent = parent->parent;
80 static void fill_kobj_path(struct kobject *kobj, char *path, int length)
82 struct kobject * parent;
85 for (parent = kobj; parent; parent = parent->parent) {
86 int cur = strlen(kobject_name(parent));
87 /* back up enough to print this name with '/' */
89 strncpy (path + length, kobject_name(parent), cur);
90 *(path + --length) = '/';
93 pr_debug("%s: path = '%s'\n",__FUNCTION__,path);
97 * kobject_get_path - generate and return the path associated with a given kobj
98 * and kset pair. The result must be freed by the caller with kfree().
100 * @kobj: kobject in question, with which to build the path
101 * @gfp_mask: the allocation type used to allocate the path
103 char *kobject_get_path(struct kobject *kobj, int gfp_mask)
108 len = get_kobj_path_length(kobj);
109 path = kmalloc(len, gfp_mask);
112 memset(path, 0x00, len);
113 fill_kobj_path(kobj, path, len);
119 * kobject_init - initialize object.
120 * @kobj: object in question.
122 void kobject_init(struct kobject * kobj)
124 kref_init(&kobj->kref);
125 INIT_LIST_HEAD(&kobj->entry);
126 kobj->kset = kset_get(kobj->kset);
131 * unlink - remove kobject from kset list.
134 * Remove the kobject from the kset list and decrement
135 * its parent's refcount.
136 * This is separated out, so we can use it in both
137 * kobject_del() and kobject_add() on error.
140 static void unlink(struct kobject * kobj)
143 spin_lock(&kobj->kset->list_lock);
144 list_del_init(&kobj->entry);
145 spin_unlock(&kobj->kset->list_lock);
151 * kobject_add - add an object to the hierarchy.
155 int kobject_add(struct kobject * kobj)
158 struct kobject * parent;
160 if (!(kobj = kobject_get(kobj)))
163 kobj->k_name = kobj->name;
164 parent = kobject_get(kobj->parent);
166 pr_debug("kobject %s: registering. parent: %s, set: %s\n",
167 kobject_name(kobj), parent ? kobject_name(parent) : "<NULL>",
168 kobj->kset ? kobj->kset->kobj.name : "<NULL>" );
171 spin_lock(&kobj->kset->list_lock);
174 parent = kobject_get(&kobj->kset->kobj);
176 list_add_tail(&kobj->entry,&kobj->kset->list);
177 spin_unlock(&kobj->kset->list_lock);
179 kobj->parent = parent;
181 error = create_dir(kobj);
183 /* unlink does the kobject_put() for us */
194 * kobject_register - initialize and add an object.
195 * @kobj: object in question.
198 int kobject_register(struct kobject * kobj)
203 error = kobject_add(kobj);
205 printk("kobject_register failed for %s (%d)\n",
206 kobject_name(kobj),error);
209 kobject_hotplug(kobj, KOBJ_ADD);
217 * kobject_set_name - Set the name of an object
219 * @fmt: format string used to build the name
221 * If strlen(name) >= KOBJ_NAME_LEN, then use a dynamically allocated
222 * string that @kobj->k_name points to. Otherwise, use the static
225 int kobject_set_name(struct kobject * kobj, const char * fmt, ...)
228 int limit = KOBJ_NAME_LEN;
234 * First, try the static array
237 need = vsnprintf(kobj->name,limit,fmt,args);
243 * Need more space? Allocate it and try again
246 name = kmalloc(limit,GFP_KERNEL);
252 need = vsnprintf(name,limit,fmt,args);
255 /* Still? Give up. */
263 /* Free the old name, if necessary. */
264 if (kobj->k_name && kobj->k_name != kobj->name)
267 /* Now, set the new name */
273 EXPORT_SYMBOL(kobject_set_name);
277 * kobject_rename - change the name of an object
278 * @kobj: object in question.
279 * @new_name: object's new name
282 int kobject_rename(struct kobject * kobj, const char *new_name)
286 kobj = kobject_get(kobj);
289 error = sysfs_rename_dir(kobj, new_name);
296 * kobject_del - unlink kobject from hierarchy.
300 void kobject_del(struct kobject * kobj)
302 sysfs_remove_dir(kobj);
307 * kobject_unregister - remove object from hierarchy and decrement refcount.
308 * @kobj: object going away.
311 void kobject_unregister(struct kobject * kobj)
313 pr_debug("kobject %s: unregistering\n",kobject_name(kobj));
314 kobject_hotplug(kobj, KOBJ_REMOVE);
320 * kobject_get - increment refcount for object.
324 struct kobject * kobject_get(struct kobject * kobj)
327 kref_get(&kobj->kref);
332 * kobject_cleanup - free kobject resources.
336 void kobject_cleanup(struct kobject * kobj)
338 struct kobj_type * t = get_ktype(kobj);
339 struct kset * s = kobj->kset;
340 struct kobject * parent = kobj->parent;
342 pr_debug("kobject %s: cleaning up\n",kobject_name(kobj));
343 if (kobj->k_name != kobj->name)
354 static void kobject_release(struct kref *kref)
356 kobject_cleanup(container_of(kref, struct kobject, kref));
360 * kobject_put - decrement refcount for object.
363 * Decrement the refcount, and if 0, call kobject_cleanup().
365 void kobject_put(struct kobject * kobj)
368 kref_put(&kobj->kref, kobject_release);
373 * kset_init - initialize a kset for use
377 void kset_init(struct kset * k)
379 kobject_init(&k->kobj);
380 INIT_LIST_HEAD(&k->list);
381 spin_lock_init(&k->list_lock);
386 * kset_add - add a kset object to the hierarchy.
389 * Simply, this adds the kset's embedded kobject to the
391 * We also try to make sure that the kset's embedded kobject
392 * has a parent before it is added. We only care if the embedded
393 * kobject is not part of a kset itself, since kobject_add()
394 * assigns a parent in that case.
395 * If that is the case, and the kset has a controlling subsystem,
396 * then we set the kset's parent to be said subsystem.
399 int kset_add(struct kset * k)
401 if (!k->kobj.parent && !k->kobj.kset && k->subsys)
402 k->kobj.parent = &k->subsys->kset.kobj;
404 return kobject_add(&k->kobj);
409 * kset_register - initialize and add a kset.
413 int kset_register(struct kset * k)
421 * kset_unregister - remove a kset.
425 void kset_unregister(struct kset * k)
427 kobject_unregister(&k->kobj);
432 * kset_find_obj - search for object in kset.
433 * @kset: kset we're looking in.
434 * @name: object's name.
436 * Lock kset via @kset->subsys, and iterate over @kset->list,
437 * looking for a matching kobject. If matching object is found
438 * take a reference and return the object.
441 struct kobject * kset_find_obj(struct kset * kset, const char * name)
443 struct list_head * entry;
444 struct kobject * ret = NULL;
446 spin_lock(&kset->list_lock);
447 list_for_each(entry,&kset->list) {
448 struct kobject * k = to_kobj(entry);
449 if (kobject_name(k) && !strcmp(kobject_name(k),name)) {
450 ret = kobject_get(k);
454 spin_unlock(&kset->list_lock);
459 void subsystem_init(struct subsystem * s)
461 init_rwsem(&s->rwsem);
466 * subsystem_register - register a subsystem.
467 * @s: the subsystem we're registering.
469 * Once we register the subsystem, we want to make sure that
470 * the kset points back to this subsystem for correct usage of
474 int subsystem_register(struct subsystem * s)
479 pr_debug("subsystem %s: registering\n",s->kset.kobj.name);
481 if (!(error = kset_add(&s->kset))) {
488 void subsystem_unregister(struct subsystem * s)
490 pr_debug("subsystem %s: unregistering\n",s->kset.kobj.name);
491 kset_unregister(&s->kset);
496 * subsystem_create_file - export sysfs attribute file.
498 * @a: subsystem attribute descriptor.
501 int subsys_create_file(struct subsystem * s, struct subsys_attribute * a)
505 error = sysfs_create_file(&s->kset.kobj,&a->attr);
513 * subsystem_remove_file - remove sysfs attribute file.
515 * @a: attribute desciptor.
518 void subsys_remove_file(struct subsystem * s, struct subsys_attribute * a)
521 sysfs_remove_file(&s->kset.kobj,&a->attr);
526 EXPORT_SYMBOL(kobject_init);
527 EXPORT_SYMBOL(kobject_register);
528 EXPORT_SYMBOL(kobject_unregister);
529 EXPORT_SYMBOL(kobject_get);
530 EXPORT_SYMBOL(kobject_put);
531 EXPORT_SYMBOL(kobject_add);
532 EXPORT_SYMBOL(kobject_del);
534 EXPORT_SYMBOL(kset_register);
535 EXPORT_SYMBOL(kset_unregister);
536 EXPORT_SYMBOL(kset_find_obj);
538 EXPORT_SYMBOL(subsystem_init);
539 EXPORT_SYMBOL(subsystem_register);
540 EXPORT_SYMBOL(subsystem_unregister);
541 EXPORT_SYMBOL(subsys_create_file);
542 EXPORT_SYMBOL(subsys_remove_file);