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 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_add - add an object to the hierarchy.
164 int kobject_add(struct kobject * kobj)
167 struct kobject * parent;
169 if (!(kobj = kobject_get(kobj)))
172 kobject_set_name(kobj, "NO_NAME");
173 if (!*kobj->k_name) {
174 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 ? kobject_name(&kobj->kset->kobj) : "<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);
198 /* unlink does the kobject_put() for us */
202 /* be noisy on error issues */
203 if (error == -EEXIST)
204 printk(KERN_ERR "kobject_add failed for %s with "
205 "-EEXIST, don't try to register things with "
206 "the same name in the same directory.\n",
209 printk(KERN_ERR "kobject_add failed for %s (%d)\n",
210 kobject_name(kobj), error);
218 * kobject_register - initialize and add an object.
219 * @kobj: object in question.
222 int kobject_register(struct kobject * kobj)
227 error = kobject_add(kobj);
229 kobject_uevent(kobj, KOBJ_ADD);
236 * kobject_set_name - Set the name of an object
238 * @fmt: format string used to build the name
240 * If strlen(name) >= KOBJ_NAME_LEN, then use a dynamically allocated
241 * string that @kobj->k_name points to. Otherwise, use the static
244 int kobject_set_name(struct kobject * kobj, const char * fmt, ...)
252 /* find out how big a buffer we need */
253 name = kmalloc(1024, GFP_KERNEL);
259 need = vsnprintf(name, 1024, fmt, args);
263 /* Allocate the new space and copy the string in */
265 name = kmalloc(limit, GFP_KERNEL);
271 need = vsnprintf(name, limit, fmt, args);
274 /* something wrong with the string we copied? */
281 /* Free the old name, if necessary. */
284 /* Now, set the new name */
289 EXPORT_SYMBOL(kobject_set_name);
292 * kobject_rename - change the name of an object
293 * @kobj: object in question.
294 * @new_name: object's new name
297 int kobject_rename(struct kobject * kobj, const char *new_name)
300 const char *devpath = NULL;
301 char *devpath_string = NULL;
304 kobj = kobject_get(kobj);
310 devpath = kobject_get_path(kobj, GFP_KERNEL);
315 devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
316 if (!devpath_string) {
320 sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
321 envp[0] = devpath_string;
323 /* Note : if we want to send the new name alone, not the full path,
324 * we could probably use kobject_name(kobj); */
326 error = sysfs_rename_dir(kobj, new_name);
328 /* This function is mostly/only used for network interface.
329 * Some hotplug package track interfaces by their name and
330 * therefore want to know when the name is changed by the user. */
332 kobject_uevent_env(kobj, KOBJ_MOVE, envp);
335 kfree(devpath_string);
343 * kobject_move - move object to another parent
344 * @kobj: object in question.
345 * @new_parent: object's new parent (can be NULL)
348 int kobject_move(struct kobject *kobj, struct kobject *new_parent)
351 struct kobject *old_parent;
352 const char *devpath = NULL;
353 char *devpath_string = NULL;
356 kobj = kobject_get(kobj);
359 new_parent = kobject_get(new_parent);
362 new_parent = kobject_get(&kobj->kset->kobj);
364 /* old object path */
365 devpath = kobject_get_path(kobj, GFP_KERNEL);
370 devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
371 if (!devpath_string) {
375 sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
376 envp[0] = devpath_string;
378 error = sysfs_move_dir(kobj, new_parent);
381 old_parent = kobj->parent;
382 kobj->parent = new_parent;
384 kobject_put(old_parent);
385 kobject_uevent_env(kobj, KOBJ_MOVE, envp);
387 kobject_put(new_parent);
389 kfree(devpath_string);
395 * kobject_del - unlink kobject from hierarchy.
399 void kobject_del(struct kobject * kobj)
403 sysfs_remove_dir(kobj);
408 * kobject_unregister - remove object from hierarchy and decrement refcount.
409 * @kobj: object going away.
412 void kobject_unregister(struct kobject * kobj)
416 pr_debug("kobject %s: unregistering\n",kobject_name(kobj));
417 kobject_uevent(kobj, KOBJ_REMOVE);
423 * kobject_get - increment refcount for object.
427 struct kobject * kobject_get(struct kobject * kobj)
430 kref_get(&kobj->kref);
435 * kobject_cleanup - free kobject resources.
439 void kobject_cleanup(struct kobject * kobj)
441 struct kobj_type * t = get_ktype(kobj);
442 struct kset * s = kobj->kset;
443 struct kobject * parent = kobj->parent;
444 const char *name = kobj->k_name;
446 pr_debug("kobject %s: cleaning up\n",kobject_name(kobj));
447 if (t && t->release) {
449 /* If we have a release function, we can guess that this was
450 * not a statically allocated kobject, so we should be safe to
459 static void kobject_release(struct kref *kref)
461 kobject_cleanup(container_of(kref, struct kobject, kref));
465 * kobject_put - decrement refcount for object.
468 * Decrement the refcount, and if 0, call kobject_cleanup().
470 void kobject_put(struct kobject * kobj)
473 kref_put(&kobj->kref, kobject_release);
477 static void dir_release(struct kobject *kobj)
482 static struct kobj_type dir_ktype = {
483 .release = dir_release,
485 .default_attrs = NULL,
489 * kobject_kset_add_dir - add sub directory of object.
490 * @kset: kset the directory is belongs to.
491 * @parent: object in which a directory is created.
492 * @name: directory name.
494 * Add a plain directory object as child of given object.
496 struct kobject *kobject_kset_add_dir(struct kset *kset,
497 struct kobject *parent, const char *name)
505 k = kzalloc(sizeof(*k), GFP_KERNEL);
511 k->ktype = &dir_ktype;
512 kobject_set_name(k, name);
513 ret = kobject_register(k);
515 printk(KERN_WARNING "%s: kobject_register error: %d\n",
525 * kobject_add_dir - add sub directory of object.
526 * @parent: object in which a directory is created.
527 * @name: directory name.
529 * Add a plain directory object as child of given object.
531 struct kobject *kobject_add_dir(struct kobject *parent, const char *name)
533 return kobject_kset_add_dir(NULL, parent, name);
537 * kset_init - initialize a kset for use
541 void kset_init(struct kset * k)
543 kobject_init(&k->kobj);
544 INIT_LIST_HEAD(&k->list);
545 spin_lock_init(&k->list_lock);
550 * kset_add - add a kset object to the hierarchy.
554 int kset_add(struct kset * k)
556 return kobject_add(&k->kobj);
561 * kset_register - initialize and add a kset.
565 int kset_register(struct kset * k)
576 kobject_uevent(&k->kobj, KOBJ_ADD);
582 * kset_unregister - remove a kset.
586 void kset_unregister(struct kset * k)
590 kobject_unregister(&k->kobj);
595 * kset_find_obj - search for object in kset.
596 * @kset: kset we're looking in.
597 * @name: object's name.
599 * Lock kset via @kset->subsys, and iterate over @kset->list,
600 * looking for a matching kobject. If matching object is found
601 * take a reference and return the object.
604 struct kobject * kset_find_obj(struct kset * kset, const char * name)
606 struct list_head * entry;
607 struct kobject * ret = NULL;
609 spin_lock(&kset->list_lock);
610 list_for_each(entry,&kset->list) {
611 struct kobject * k = to_kobj(entry);
612 if (kobject_name(k) && !strcmp(kobject_name(k),name)) {
613 ret = kobject_get(k);
617 spin_unlock(&kset->list_lock);
621 void subsystem_init(struct kset *s)
626 int subsystem_register(struct kset *s)
628 return kset_register(s);
631 void subsystem_unregister(struct kset *s)
637 * subsystem_create_file - export sysfs attribute file.
639 * @a: subsystem attribute descriptor.
642 int subsys_create_file(struct kset *s, struct subsys_attribute *a)
650 error = sysfs_create_file(&s->kobj, &a->attr);
656 EXPORT_SYMBOL(kobject_init);
657 EXPORT_SYMBOL(kobject_register);
658 EXPORT_SYMBOL(kobject_unregister);
659 EXPORT_SYMBOL(kobject_get);
660 EXPORT_SYMBOL(kobject_put);
661 EXPORT_SYMBOL(kobject_add);
662 EXPORT_SYMBOL(kobject_del);
664 EXPORT_SYMBOL(kset_register);
665 EXPORT_SYMBOL(kset_unregister);
667 EXPORT_SYMBOL(subsystem_register);
668 EXPORT_SYMBOL(subsystem_unregister);
669 EXPORT_SYMBOL(subsys_create_file);