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, struct dentry *shadow_parent)
50 if (kobject_name(kobj)) {
51 error = sysfs_create_dir(kobj, shadow_parent);
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 if (kobject_name(parent) == NULL)
77 length += strlen(kobject_name(parent)) + 1;
78 parent = parent->parent;
83 static void fill_kobj_path(struct kobject *kobj, char *path, int length)
85 struct kobject * parent;
88 for (parent = kobj; parent; parent = parent->parent) {
89 int cur = strlen(kobject_name(parent));
90 /* back up enough to print this name with '/' */
92 strncpy (path + length, kobject_name(parent), cur);
93 *(path + --length) = '/';
96 pr_debug("%s: path = '%s'\n",__FUNCTION__,path);
100 * kobject_get_path - generate and return the path associated with a given kobj and kset pair.
102 * @kobj: kobject in question, with which to build the path
103 * @gfp_mask: the allocation type used to allocate the path
105 * The result must be freed by the caller with kfree().
107 char *kobject_get_path(struct kobject *kobj, gfp_t gfp_mask)
112 len = get_kobj_path_length(kobj);
115 path = kzalloc(len, gfp_mask);
118 fill_kobj_path(kobj, path, len);
122 EXPORT_SYMBOL_GPL(kobject_get_path);
125 * kobject_init - initialize object.
126 * @kobj: object in question.
128 void kobject_init(struct kobject * kobj)
132 kref_init(&kobj->kref);
133 INIT_LIST_HEAD(&kobj->entry);
134 init_waitqueue_head(&kobj->poll);
135 kobj->kset = kset_get(kobj->kset);
140 * unlink - remove kobject from kset list.
143 * Remove the kobject from the kset list and decrement
144 * its parent's refcount.
145 * This is separated out, so we can use it in both
146 * kobject_del() and kobject_add() on error.
149 static void unlink(struct kobject * kobj)
152 spin_lock(&kobj->kset->list_lock);
153 list_del_init(&kobj->entry);
154 spin_unlock(&kobj->kset->list_lock);
160 * kobject_shadow_add - add an object to the hierarchy.
162 * @shadow_parent: sysfs directory to add to.
165 int kobject_shadow_add(struct kobject * kobj, struct dentry *shadow_parent)
168 struct kobject * parent;
170 if (!(kobj = kobject_get(kobj)))
173 kobj->k_name = kobj->name;
174 if (!*kobj->k_name) {
175 pr_debug("kobject attempted to be registered with no name!\n");
179 parent = kobject_get(kobj->parent);
181 pr_debug("kobject %s: registering. parent: %s, set: %s\n",
182 kobject_name(kobj), parent ? kobject_name(parent) : "<NULL>",
183 kobj->kset ? kobj->kset->kobj.name : "<NULL>" );
186 spin_lock(&kobj->kset->list_lock);
189 parent = kobject_get(&kobj->kset->kobj);
191 list_add_tail(&kobj->entry,&kobj->kset->list);
192 spin_unlock(&kobj->kset->list_lock);
193 kobj->parent = parent;
196 error = create_dir(kobj, shadow_parent);
198 /* unlink does the kobject_put() for us */
202 /* be noisy on error issues */
203 if (error == -EEXIST)
204 printk("kobject_add failed for %s with -EEXIST, "
205 "don't try to register things with the "
206 "same name in the same directory.\n",
209 printk("kobject_add failed for %s (%d)\n",
210 kobject_name(kobj), error);
218 * kobject_add - add an object to the hierarchy.
221 int kobject_add(struct kobject * kobj)
223 return kobject_shadow_add(kobj, NULL);
228 * kobject_register - initialize and add an object.
229 * @kobj: object in question.
232 int kobject_register(struct kobject * kobj)
237 error = kobject_add(kobj);
239 kobject_uevent(kobj, KOBJ_ADD);
246 * kobject_set_name - Set the name of an object
248 * @fmt: format string used to build the name
250 * If strlen(name) >= KOBJ_NAME_LEN, then use a dynamically allocated
251 * string that @kobj->k_name points to. Otherwise, use the static
254 int kobject_set_name(struct kobject * kobj, const char * fmt, ...)
257 int limit = KOBJ_NAME_LEN;
263 * First, try the static array
266 need = vsnprintf(kobj->name,limit,fmt,args);
272 * Need more space? Allocate it and try again
275 name = kmalloc(limit,GFP_KERNEL);
281 need = vsnprintf(name,limit,fmt,args);
284 /* Still? Give up. */
292 /* Free the old name, if necessary. */
293 if (kobj->k_name && kobj->k_name != kobj->name)
296 /* Now, set the new name */
302 EXPORT_SYMBOL(kobject_set_name);
306 * kobject_rename - change the name of an object
307 * @kobj: object in question.
308 * @new_name: object's new name
311 int kobject_rename(struct kobject * kobj, const char *new_name)
314 const char *devpath = NULL;
315 char *devpath_string = NULL;
318 kobj = kobject_get(kobj);
324 devpath = kobject_get_path(kobj, GFP_KERNEL);
329 devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
330 if (!devpath_string) {
334 sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
335 envp[0] = devpath_string;
337 /* Note : if we want to send the new name alone, not the full path,
338 * we could probably use kobject_name(kobj); */
340 error = sysfs_rename_dir(kobj, kobj->parent->dentry, new_name);
342 /* This function is mostly/only used for network interface.
343 * Some hotplug package track interfaces by their name and
344 * therefore want to know when the name is changed by the user. */
346 kobject_uevent_env(kobj, KOBJ_MOVE, envp);
349 kfree(devpath_string);
357 * kobject_rename - change the name of an object
358 * @kobj: object in question.
359 * @new_parent: object's new parent
360 * @new_name: object's new name
363 int kobject_shadow_rename(struct kobject * kobj, struct dentry *new_parent,
364 const char *new_name)
368 kobj = kobject_get(kobj);
371 error = sysfs_rename_dir(kobj, new_parent, new_name);
378 * kobject_move - move object to another parent
379 * @kobj: object in question.
380 * @new_parent: object's new parent (can be NULL)
383 int kobject_move(struct kobject *kobj, struct kobject *new_parent)
386 struct kobject *old_parent;
387 const char *devpath = NULL;
388 char *devpath_string = NULL;
391 kobj = kobject_get(kobj);
394 new_parent = kobject_get(new_parent);
397 new_parent = kobject_get(&kobj->kset->kobj);
399 /* old object path */
400 devpath = kobject_get_path(kobj, GFP_KERNEL);
405 devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
406 if (!devpath_string) {
410 sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
411 envp[0] = devpath_string;
413 error = sysfs_move_dir(kobj, new_parent);
416 old_parent = kobj->parent;
417 kobj->parent = new_parent;
419 kobject_put(old_parent);
420 kobject_uevent_env(kobj, KOBJ_MOVE, envp);
422 kobject_put(new_parent);
424 kfree(devpath_string);
430 * kobject_del - unlink kobject from hierarchy.
434 void kobject_del(struct kobject * kobj)
438 sysfs_remove_dir(kobj);
443 * kobject_unregister - remove object from hierarchy and decrement refcount.
444 * @kobj: object going away.
447 void kobject_unregister(struct kobject * kobj)
451 pr_debug("kobject %s: unregistering\n",kobject_name(kobj));
452 kobject_uevent(kobj, KOBJ_REMOVE);
458 * kobject_get - increment refcount for object.
462 struct kobject * kobject_get(struct kobject * kobj)
465 kref_get(&kobj->kref);
470 * kobject_cleanup - free kobject resources.
474 void kobject_cleanup(struct kobject * kobj)
476 struct kobj_type * t = get_ktype(kobj);
477 struct kset * s = kobj->kset;
478 struct kobject * parent = kobj->parent;
480 pr_debug("kobject %s: cleaning up\n",kobject_name(kobj));
481 if (kobj->k_name != kobj->name)
491 static void kobject_release(struct kref *kref)
493 kobject_cleanup(container_of(kref, struct kobject, kref));
497 * kobject_put - decrement refcount for object.
500 * Decrement the refcount, and if 0, call kobject_cleanup().
502 void kobject_put(struct kobject * kobj)
505 kref_put(&kobj->kref, kobject_release);
509 static void dir_release(struct kobject *kobj)
514 static struct kobj_type dir_ktype = {
515 .release = dir_release,
517 .default_attrs = NULL,
521 * kobject__kset_add_dir - add sub directory of object.
522 * @kset: kset the directory is belongs to.
523 * @parent: object in which a directory is created.
524 * @name: directory name.
526 * Add a plain directory object as child of given object.
528 struct kobject *kobject_kset_add_dir(struct kset *kset,
529 struct kobject *parent, const char *name)
537 k = kzalloc(sizeof(*k), GFP_KERNEL);
543 k->ktype = &dir_ktype;
544 kobject_set_name(k, name);
545 ret = kobject_register(k);
547 printk(KERN_WARNING "kobject_add_dir: "
548 "kobject_register error: %d\n", ret);
556 struct kobject *kobject_add_dir(struct kobject *parent, const char *name)
558 return kobject_kset_add_dir(NULL, parent, name);
562 * kset_init - initialize a kset for use
566 void kset_init(struct kset * k)
568 kobject_init(&k->kobj);
569 INIT_LIST_HEAD(&k->list);
570 spin_lock_init(&k->list_lock);
575 * kset_add - add a kset object to the hierarchy.
578 * Simply, this adds the kset's embedded kobject to the
580 * We also try to make sure that the kset's embedded kobject
581 * has a parent before it is added. We only care if the embedded
582 * kobject is not part of a kset itself, since kobject_add()
583 * assigns a parent in that case.
584 * If that is the case, and the kset has a controlling subsystem,
585 * then we set the kset's parent to be said subsystem.
588 int kset_add(struct kset * k)
590 if (!k->kobj.parent && !k->kobj.kset && k->subsys)
591 k->kobj.parent = &k->subsys->kset.kobj;
593 return kobject_add(&k->kobj);
598 * kset_register - initialize and add a kset.
602 int kset_register(struct kset * k)
612 * kset_unregister - remove a kset.
616 void kset_unregister(struct kset * k)
620 kobject_unregister(&k->kobj);
625 * kset_find_obj - search for object in kset.
626 * @kset: kset we're looking in.
627 * @name: object's name.
629 * Lock kset via @kset->subsys, and iterate over @kset->list,
630 * looking for a matching kobject. If matching object is found
631 * take a reference and return the object.
634 struct kobject * kset_find_obj(struct kset * kset, const char * name)
636 struct list_head * entry;
637 struct kobject * ret = NULL;
639 spin_lock(&kset->list_lock);
640 list_for_each(entry,&kset->list) {
641 struct kobject * k = to_kobj(entry);
642 if (kobject_name(k) && !strcmp(kobject_name(k),name)) {
643 ret = kobject_get(k);
647 spin_unlock(&kset->list_lock);
652 void subsystem_init(struct subsystem * s)
654 init_rwsem(&s->rwsem);
659 * subsystem_register - register a subsystem.
660 * @s: the subsystem we're registering.
662 * Once we register the subsystem, we want to make sure that
663 * the kset points back to this subsystem for correct usage of
667 int subsystem_register(struct subsystem * s)
675 pr_debug("subsystem %s: registering\n",s->kset.kobj.name);
677 if (!(error = kset_add(&s->kset))) {
684 void subsystem_unregister(struct subsystem * s)
688 pr_debug("subsystem %s: unregistering\n",s->kset.kobj.name);
689 kset_unregister(&s->kset);
694 * subsystem_create_file - export sysfs attribute file.
696 * @a: subsystem attribute descriptor.
699 int subsys_create_file(struct subsystem * s, struct subsys_attribute * a)
707 error = sysfs_create_file(&s->kset.kobj,&a->attr);
715 * subsystem_remove_file - remove sysfs attribute file.
717 * @a: attribute desciptor.
720 void subsys_remove_file(struct subsystem * s, struct subsys_attribute * a)
723 sysfs_remove_file(&s->kset.kobj,&a->attr);
729 EXPORT_SYMBOL(kobject_init);
730 EXPORT_SYMBOL(kobject_register);
731 EXPORT_SYMBOL(kobject_unregister);
732 EXPORT_SYMBOL(kobject_get);
733 EXPORT_SYMBOL(kobject_put);
734 EXPORT_SYMBOL(kobject_add);
735 EXPORT_SYMBOL(kobject_del);
737 EXPORT_SYMBOL(kset_register);
738 EXPORT_SYMBOL(kset_unregister);
740 EXPORT_SYMBOL(subsystem_register);
741 EXPORT_SYMBOL(subsystem_unregister);
742 EXPORT_SYMBOL(subsys_create_file);