2 * kobject.c - library routines for handling generic kernel objects
4 * Copyright (c) 2002-2003 Patrick Mochel <mochel@osdl.org>
5 * Copyright (c) 2006-2007 Greg Kroah-Hartman <greg@kroah.com>
6 * Copyright (c) 2006-2007 Novell Inc.
8 * This file is released under the GPLv2.
11 * Please see the file Documentation/kobject.txt for critical information
12 * about using the kobject interface.
15 #include <linux/kobject.h>
16 #include <linux/string.h>
17 #include <linux/module.h>
18 #include <linux/stat.h>
19 #include <linux/slab.h>
22 * populate_dir - populate directory with attributes.
23 * @kobj: object we're working on.
25 * Most subsystems have a set of default attributes that
26 * are associated with an object that registers with them.
27 * This is a helper called during object registration that
28 * loops through the default attributes of the subsystem
29 * and creates attributes files for them in sysfs.
33 static int populate_dir(struct kobject * kobj)
35 struct kobj_type * t = get_ktype(kobj);
36 struct attribute * attr;
40 if (t && t->default_attrs) {
41 for (i = 0; (attr = t->default_attrs[i]) != NULL; i++) {
42 if ((error = sysfs_create_file(kobj,attr)))
49 static int create_dir(struct kobject * kobj)
52 if (kobject_name(kobj)) {
53 error = sysfs_create_dir(kobj);
55 if ((error = populate_dir(kobj)))
56 sysfs_remove_dir(kobj);
62 static inline struct kobject * to_kobj(struct list_head * entry)
64 return container_of(entry,struct kobject,entry);
67 static int get_kobj_path_length(struct kobject *kobj)
70 struct kobject * parent = kobj;
72 /* walk up the ancestors until we hit the one pointing to the
74 * Add 1 to strlen for leading '/' of each level.
77 if (kobject_name(parent) == NULL)
79 length += strlen(kobject_name(parent)) + 1;
80 parent = parent->parent;
85 static void fill_kobj_path(struct kobject *kobj, char *path, int length)
87 struct kobject * parent;
90 for (parent = kobj; parent; parent = parent->parent) {
91 int cur = strlen(kobject_name(parent));
92 /* back up enough to print this name with '/' */
94 strncpy (path + length, kobject_name(parent), cur);
95 *(path + --length) = '/';
98 pr_debug("kobject: '%s' (%p): %s: path = '%s'\n", kobject_name(kobj),
99 kobj, __FUNCTION__,path);
103 * kobject_get_path - generate and return the path associated with a given kobj and kset pair.
105 * @kobj: kobject in question, with which to build the path
106 * @gfp_mask: the allocation type used to allocate the path
108 * The result must be freed by the caller with kfree().
110 char *kobject_get_path(struct kobject *kobj, gfp_t gfp_mask)
115 len = get_kobj_path_length(kobj);
118 path = kzalloc(len, gfp_mask);
121 fill_kobj_path(kobj, path, len);
125 EXPORT_SYMBOL_GPL(kobject_get_path);
128 * kobject_init - initialize object.
129 * @kobj: object in question.
131 void kobject_init(struct kobject * kobj)
135 kref_init(&kobj->kref);
136 INIT_LIST_HEAD(&kobj->entry);
141 * unlink - remove kobject from kset list.
144 * Remove the kobject from the kset list and decrement
145 * its parent's refcount.
146 * This is separated out, so we can use it in both
147 * kobject_del() and kobject_add_internal() on error.
150 static void unlink(struct kobject * kobj)
152 struct kobject *parent = kobj->parent;
155 spin_lock(&kobj->kset->list_lock);
156 list_del_init(&kobj->entry);
157 spin_unlock(&kobj->kset->list_lock);
164 static int kobject_add_internal(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 (%p) attempted to be registered with no "
180 parent = kobject_get(kobj->parent);
182 pr_debug("kobject: '%s' (%p): %s: parent: '%s', set: '%s'\n",
183 kobject_name(kobj), kobj, __FUNCTION__,
184 parent ? kobject_name(parent) : "<NULL>",
185 kobj->kset ? kobject_name(&kobj->kset->kobj) : "<NULL>" );
188 kobj->kset = kset_get(kobj->kset);
191 parent = kobject_get(&kobj->kset->kobj);
193 * If the kset is our parent, get a second
194 * reference, we drop both the kset and the
195 * parent ref on cleanup
200 spin_lock(&kobj->kset->list_lock);
201 list_add_tail(&kobj->entry, &kobj->kset->list);
202 spin_unlock(&kobj->kset->list_lock);
203 kobj->parent = parent;
206 error = create_dir(kobj);
208 /* unlink does the kobject_put() for us */
211 /* be noisy on error issues */
212 if (error == -EEXIST)
213 printk(KERN_ERR "%s failed for %s with "
214 "-EEXIST, don't try to register things with "
215 "the same name in the same directory.\n",
216 __FUNCTION__, kobject_name(kobj));
218 printk(KERN_ERR "%s failed for %s (%d)\n",
219 __FUNCTION__, kobject_name(kobj), error);
227 * kobject_register - initialize and add an object.
228 * @kobj: object in question.
231 int kobject_register(struct kobject * kobj)
236 error = kobject_add(kobj);
238 kobject_uevent(kobj, KOBJ_ADD);
244 * kobject_set_name_vargs - Set the name of an kobject
245 * @kobj: struct kobject to set the name of
246 * @fmt: format string used to build the name
247 * @vargs: vargs to format the string.
249 static int kobject_set_name_vargs(struct kobject *kobj, const char *fmt,
256 name = kvasprintf(GFP_KERNEL, fmt, vargs);
262 /* Free the old name, if necessary. */
265 /* Now, set the new name */
272 * kobject_set_name - Set the name of a kobject
273 * @kobj: struct kobject to set the name of
274 * @fmt: format string used to build the name
276 * This sets the name of the kobject. If you have already added the
277 * kobject to the system, you must call kobject_rename() in order to
278 * change the name of the kobject.
280 int kobject_set_name(struct kobject *kobj, const char *fmt, ...)
286 retval = kobject_set_name_vargs(kobj, fmt, args);
291 EXPORT_SYMBOL(kobject_set_name);
294 * kobject_init_ng - initialize a kobject structure
295 * @kobj: pointer to the kobject to initialize
296 * @ktype: pointer to the ktype for this kobject.
298 * This function will properly initialize a kobject such that it can then
299 * be passed to the kobject_add() call.
301 * After this function is called, the kobject MUST be cleaned up by a call
302 * to kobject_put(), not by a call to kfree directly to ensure that all of
303 * the memory is cleaned up properly.
305 void kobject_init_ng(struct kobject *kobj, struct kobj_type *ktype)
310 err_str = "invalid kobject pointer!";
314 err_str = "must have a ktype to be initialized properly!\n";
317 if (atomic_read(&kobj->kref.refcount)) {
318 /* do not error out as sometimes we can recover */
319 printk(KERN_ERR "kobject: reference count is already set, "
320 "something is seriously wrong.\n");
324 kref_init(&kobj->kref);
325 INIT_LIST_HEAD(&kobj->entry);
330 printk(KERN_ERR "kobject: %s\n", err_str);
333 EXPORT_SYMBOL(kobject_init_ng);
335 static int kobject_add_varg(struct kobject *kobj, struct kobject *parent,
336 const char *fmt, va_list vargs)
342 retval = kobject_set_name_vargs(kobj, fmt, aq);
345 printk(KERN_ERR "kobject: can not set name properly!\n");
348 kobj->parent = parent;
349 return kobject_add_internal(kobj);
353 * kobject_add - the main kobject add function
354 * @kobj: the kobject to add
355 * @parent: pointer to the parent of the kobject.
356 * @fmt: format to name the kobject with.
358 * The kobject name is set and added to the kobject hierarchy in this
361 * If @parent is set, then the parent of the @kobj will be set to it.
362 * If @parent is NULL, then the parent of the @kobj will be set to the
363 * kobject associted with the kset assigned to this kobject. If no kset
364 * is assigned to the kobject, then the kobject will be located in the
365 * root of the sysfs tree.
367 * If this function returns an error, kobject_put() must be called to
368 * properly clean up the memory associated with the object.
370 * If the function is successful, the only way to properly clean up the
371 * memory is with a call to kobject_del(), in which case, a call to
372 * kobject_put() is not necessary (kobject_del() does the final
373 * kobject_put() to call the release function in the ktype's release
376 * Under no instance should the kobject that is passed to this function
377 * be directly freed with a call to kfree(), that can leak memory.
379 * Note, no uevent will be created with this call, the caller should set
380 * up all of the necessary sysfs files for the object and then call
381 * kobject_uevent() with the UEVENT_ADD parameter to ensure that
382 * userspace is properly notified of this kobject's creation.
384 int kobject_add(struct kobject *kobj, struct kobject *parent,
385 const char *fmt, ...)
394 retval = kobject_add_varg(kobj, parent, fmt, args);
399 EXPORT_SYMBOL(kobject_add);
402 * kobject_init_and_add - initialize a kobject structure and add it to the kobject hierarchy
403 * @kobj: pointer to the kobject to initialize
404 * @ktype: pointer to the ktype for this kobject.
405 * @parent: pointer to the parent of this kobject.
406 * @fmt: the name of the kobject.
408 * This function combines the call to kobject_init_ng() and
409 * kobject_add(). The same type of error handling after a call to
410 * kobject_add() and kobject lifetime rules are the same here.
412 int kobject_init_and_add(struct kobject *kobj, struct kobj_type *ktype,
413 struct kobject *parent, const char *fmt, ...)
418 kobject_init_ng(kobj, ktype);
421 retval = kobject_add_varg(kobj, parent, fmt, args);
426 EXPORT_SYMBOL_GPL(kobject_init_and_add);
429 * kobject_rename - change the name of an object
430 * @kobj: object in question.
431 * @new_name: object's new name
434 int kobject_rename(struct kobject * kobj, const char *new_name)
437 const char *devpath = NULL;
438 char *devpath_string = NULL;
441 kobj = kobject_get(kobj);
447 /* see if this name is already in use */
449 struct kobject *temp_kobj;
450 temp_kobj = kset_find_obj(kobj->kset, new_name);
452 printk(KERN_WARNING "kobject '%s' cannot be renamed "
453 "to '%s' as '%s' is already in existence.\n",
454 kobject_name(kobj), new_name, new_name);
455 kobject_put(temp_kobj);
460 devpath = kobject_get_path(kobj, GFP_KERNEL);
465 devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
466 if (!devpath_string) {
470 sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
471 envp[0] = devpath_string;
474 error = sysfs_rename_dir(kobj, new_name);
476 /* This function is mostly/only used for network interface.
477 * Some hotplug package track interfaces by their name and
478 * therefore want to know when the name is changed by the user. */
480 kobject_uevent_env(kobj, KOBJ_MOVE, envp);
483 kfree(devpath_string);
491 * kobject_move - move object to another parent
492 * @kobj: object in question.
493 * @new_parent: object's new parent (can be NULL)
496 int kobject_move(struct kobject *kobj, struct kobject *new_parent)
499 struct kobject *old_parent;
500 const char *devpath = NULL;
501 char *devpath_string = NULL;
504 kobj = kobject_get(kobj);
507 new_parent = kobject_get(new_parent);
510 new_parent = kobject_get(&kobj->kset->kobj);
512 /* old object path */
513 devpath = kobject_get_path(kobj, GFP_KERNEL);
518 devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
519 if (!devpath_string) {
523 sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
524 envp[0] = devpath_string;
526 error = sysfs_move_dir(kobj, new_parent);
529 old_parent = kobj->parent;
530 kobj->parent = new_parent;
532 kobject_put(old_parent);
533 kobject_uevent_env(kobj, KOBJ_MOVE, envp);
535 kobject_put(new_parent);
537 kfree(devpath_string);
543 * kobject_del - unlink kobject from hierarchy.
547 void kobject_del(struct kobject * kobj)
551 sysfs_remove_dir(kobj);
556 * kobject_unregister - remove object from hierarchy and decrement refcount.
557 * @kobj: object going away.
560 void kobject_unregister(struct kobject * kobj)
564 pr_debug("kobject: '%s' (%p): %s\n",
565 kobject_name(kobj), kobj, __FUNCTION__);
566 kobject_uevent(kobj, KOBJ_REMOVE);
572 * kobject_get - increment refcount for object.
576 struct kobject * kobject_get(struct kobject * kobj)
579 kref_get(&kobj->kref);
584 * kobject_cleanup - free kobject resources.
585 * @kobj: object to cleanup
587 static void kobject_cleanup(struct kobject *kobj)
589 struct kobj_type * t = get_ktype(kobj);
590 struct kset * s = kobj->kset;
591 const char *name = kobj->k_name;
593 pr_debug("kobject: '%s' (%p): %s\n",
594 kobject_name(kobj), kobj, __FUNCTION__);
595 if (t && t->release) {
597 /* If we have a release function, we can guess that this was
598 * not a statically allocated kobject, so we should be safe to
606 static void kobject_release(struct kref *kref)
608 kobject_cleanup(container_of(kref, struct kobject, kref));
612 * kobject_put - decrement refcount for object.
615 * Decrement the refcount, and if 0, call kobject_cleanup().
617 void kobject_put(struct kobject * kobj)
620 kref_put(&kobj->kref, kobject_release);
623 static void dynamic_kobj_release(struct kobject *kobj)
625 pr_debug("kobject: '%s' (%p): %s\n",
626 kobject_name(kobj), kobj, __FUNCTION__);
630 static struct kobj_type dynamic_kobj_ktype = {
631 .release = dynamic_kobj_release,
632 .sysfs_ops = &kobj_sysfs_ops,
636 * kobject_create - create a struct kobject dynamically
638 * This function creates a kobject structure dynamically and sets it up
639 * to be a "dynamic" kobject with a default release function set up.
641 * If the kobject was not able to be created, NULL will be returned.
642 * The kobject structure returned from here must be cleaned up with a
643 * call to kobject_put() and not kfree(), as kobject_init_ng() has
644 * already been called on this structure.
646 struct kobject *kobject_create(void)
648 struct kobject *kobj;
650 kobj = kzalloc(sizeof(*kobj), GFP_KERNEL);
654 kobject_init_ng(kobj, &dynamic_kobj_ktype);
659 * kobject_create_and_add - create a struct kobject dynamically and register it with sysfs
661 * @name: the name for the kset
662 * @parent: the parent kobject of this kobject, if any.
664 * This function creates a kset structure dynamically and registers it
665 * with sysfs. When you are finished with this structure, call
666 * kobject_unregister() and the structure will be dynamically freed when
667 * it is no longer being used.
669 * If the kobject was not able to be created, NULL will be returned.
671 struct kobject *kobject_create_and_add(const char *name, struct kobject *parent)
673 struct kobject *kobj;
676 kobj = kobject_create();
680 retval = kobject_add(kobj, parent, "%s", name);
682 printk(KERN_WARNING "%s: kobject_add error: %d\n",
683 __FUNCTION__, retval);
689 EXPORT_SYMBOL_GPL(kobject_create_and_add);
692 * kset_init - initialize a kset for use
696 void kset_init(struct kset * k)
698 kobject_init(&k->kobj);
699 INIT_LIST_HEAD(&k->list);
700 spin_lock_init(&k->list_lock);
703 /* default kobject attribute operations */
704 static ssize_t kobj_attr_show(struct kobject *kobj, struct attribute *attr,
707 struct kobj_attribute *kattr;
710 kattr = container_of(attr, struct kobj_attribute, attr);
712 ret = kattr->show(kobj, kattr, buf);
716 static ssize_t kobj_attr_store(struct kobject *kobj, struct attribute *attr,
717 const char *buf, size_t count)
719 struct kobj_attribute *kattr;
722 kattr = container_of(attr, struct kobj_attribute, attr);
724 ret = kattr->store(kobj, kattr, buf, count);
728 struct sysfs_ops kobj_sysfs_ops = {
729 .show = kobj_attr_show,
730 .store = kobj_attr_store,
734 * kset_add - add a kset object to the hierarchy.
738 int kset_add(struct kset * k)
740 return kobject_add_internal(&k->kobj);
745 * kset_register - initialize and add a kset.
749 int kset_register(struct kset * k)
760 kobject_uevent(&k->kobj, KOBJ_ADD);
766 * kset_unregister - remove a kset.
770 void kset_unregister(struct kset * k)
774 kobject_unregister(&k->kobj);
779 * kset_find_obj - search for object in kset.
780 * @kset: kset we're looking in.
781 * @name: object's name.
783 * Lock kset via @kset->subsys, and iterate over @kset->list,
784 * looking for a matching kobject. If matching object is found
785 * take a reference and return the object.
788 struct kobject * kset_find_obj(struct kset * kset, const char * name)
790 struct list_head * entry;
791 struct kobject * ret = NULL;
793 spin_lock(&kset->list_lock);
794 list_for_each(entry,&kset->list) {
795 struct kobject * k = to_kobj(entry);
796 if (kobject_name(k) && !strcmp(kobject_name(k),name)) {
797 ret = kobject_get(k);
801 spin_unlock(&kset->list_lock);
805 static void kset_release(struct kobject *kobj)
807 struct kset *kset = container_of(kobj, struct kset, kobj);
808 pr_debug("kobject: '%s' (%p): %s\n",
809 kobject_name(kobj), kobj, __FUNCTION__);
813 static struct kobj_type kset_ktype = {
814 .sysfs_ops = &kobj_sysfs_ops,
815 .release = kset_release,
819 * kset_create - create a struct kset dynamically
821 * @name: the name for the kset
822 * @uevent_ops: a struct kset_uevent_ops for the kset
823 * @parent_kobj: the parent kobject of this kset, if any.
825 * This function creates a kset structure dynamically. This structure can
826 * then be registered with the system and show up in sysfs with a call to
827 * kset_register(). When you are finished with this structure, if
828 * kset_register() has been called, call kset_unregister() and the
829 * structure will be dynamically freed when it is no longer being used.
831 * If the kset was not able to be created, NULL will be returned.
833 static struct kset *kset_create(const char *name,
834 struct kset_uevent_ops *uevent_ops,
835 struct kobject *parent_kobj)
839 kset = kzalloc(sizeof(*kset), GFP_KERNEL);
842 kobject_set_name(&kset->kobj, name);
843 kset->uevent_ops = uevent_ops;
844 kset->kobj.parent = parent_kobj;
847 * The kobject of this kset will have a type of kset_ktype and belong to
848 * no kset itself. That way we can properly free it when it is
849 * finished being used.
851 kset->kobj.ktype = &kset_ktype;
852 kset->kobj.kset = NULL;
858 * kset_create_and_add - create a struct kset dynamically and add it to sysfs
860 * @name: the name for the kset
861 * @uevent_ops: a struct kset_uevent_ops for the kset
862 * @parent_kobj: the parent kobject of this kset, if any.
864 * This function creates a kset structure dynamically and registers it
865 * with sysfs. When you are finished with this structure, call
866 * kset_unregister() and the structure will be dynamically freed when it
867 * is no longer being used.
869 * If the kset was not able to be created, NULL will be returned.
871 struct kset *kset_create_and_add(const char *name,
872 struct kset_uevent_ops *uevent_ops,
873 struct kobject *parent_kobj)
878 kset = kset_create(name, uevent_ops, parent_kobj);
881 error = kset_register(kset);
888 EXPORT_SYMBOL_GPL(kset_create_and_add);
890 EXPORT_SYMBOL(kobject_init);
891 EXPORT_SYMBOL(kobject_register);
892 EXPORT_SYMBOL(kobject_unregister);
893 EXPORT_SYMBOL(kobject_get);
894 EXPORT_SYMBOL(kobject_put);
895 EXPORT_SYMBOL(kobject_del);
897 EXPORT_SYMBOL(kset_register);
898 EXPORT_SYMBOL(kset_unregister);