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);
127 /* add the kobject to its kset's list */
128 static void kobj_kset_join(struct kobject *kobj)
133 kset_get(kobj->kset);
134 spin_lock(&kobj->kset->list_lock);
135 list_add_tail(&kobj->entry, &kobj->kset->list);
136 spin_unlock(&kobj->kset->list_lock);
139 /* remove the kobject from its kset's list */
140 static void kobj_kset_leave(struct kobject *kobj)
145 spin_lock(&kobj->kset->list_lock);
146 list_del_init(&kobj->entry);
147 spin_unlock(&kobj->kset->list_lock);
148 kset_put(kobj->kset);
151 static void kobject_init_internal(struct kobject * kobj)
155 kref_init(&kobj->kref);
156 INIT_LIST_HEAD(&kobj->entry);
160 static int kobject_add_internal(struct kobject *kobj)
163 struct kobject * parent;
168 if (!kobj->k_name || !kobj->k_name[0]) {
169 pr_debug("kobject: (%p): attempted to be registered with empty "
175 parent = kobject_get(kobj->parent);
177 /* join kset if set, use it as parent if we do not already have one */
180 parent = kobject_get(&kobj->kset->kobj);
181 kobj_kset_join(kobj);
182 kobj->parent = parent;
185 pr_debug("kobject: '%s' (%p): %s: parent: '%s', set: '%s'\n",
186 kobject_name(kobj), kobj, __FUNCTION__,
187 parent ? kobject_name(parent) : "<NULL>",
188 kobj->kset ? kobject_name(&kobj->kset->kobj) : "<NULL>" );
190 error = create_dir(kobj);
192 kobj_kset_leave(kobj);
196 /* be noisy on error issues */
197 if (error == -EEXIST)
198 printk(KERN_ERR "%s failed for %s with "
199 "-EEXIST, don't try to register things with "
200 "the same name in the same directory.\n",
201 __FUNCTION__, kobject_name(kobj));
203 printk(KERN_ERR "%s failed for %s (%d)\n",
204 __FUNCTION__, kobject_name(kobj), error);
207 kobj->state_in_sysfs = 1;
213 * kobject_set_name_vargs - Set the name of an kobject
214 * @kobj: struct kobject to set the name of
215 * @fmt: format string used to build the name
216 * @vargs: vargs to format the string.
218 static int kobject_set_name_vargs(struct kobject *kobj, const char *fmt,
225 name = kvasprintf(GFP_KERNEL, fmt, vargs);
232 /* Free the old name, if necessary. */
235 /* Now, set the new name */
237 kobj->state_name_set = 1;
243 * kobject_set_name - Set the name of a kobject
244 * @kobj: struct kobject to set the name of
245 * @fmt: format string used to build the name
247 * This sets the name of the kobject. If you have already added the
248 * kobject to the system, you must call kobject_rename() in order to
249 * change the name of the kobject.
251 int kobject_set_name(struct kobject *kobj, const char *fmt, ...)
257 retval = kobject_set_name_vargs(kobj, fmt, args);
262 EXPORT_SYMBOL(kobject_set_name);
265 * kobject_init - initialize a kobject structure
266 * @kobj: pointer to the kobject to initialize
267 * @ktype: pointer to the ktype for this kobject.
269 * This function will properly initialize a kobject such that it can then
270 * be passed to the kobject_add() call.
272 * After this function is called, the kobject MUST be cleaned up by a call
273 * to kobject_put(), not by a call to kfree directly to ensure that all of
274 * the memory is cleaned up properly.
276 void kobject_init(struct kobject *kobj, struct kobj_type *ktype)
281 err_str = "invalid kobject pointer!";
285 err_str = "must have a ktype to be initialized properly!\n";
288 if (kobj->state_initialized) {
289 /* do not error out as sometimes we can recover */
290 printk(KERN_ERR "kobject (%p): tried to init an initialized "
291 "object, something is seriously wrong.\n", kobj);
295 kref_init(&kobj->kref);
296 INIT_LIST_HEAD(&kobj->entry);
298 kobj->state_name_set = 0;
299 kobj->state_in_sysfs = 0;
300 kobj->state_add_uevent_sent = 0;
301 kobj->state_remove_uevent_sent = 0;
302 kobj->state_initialized = 1;
306 printk(KERN_ERR "kobject (%p): %s\n", kobj, err_str);
309 EXPORT_SYMBOL(kobject_init);
311 static int kobject_add_varg(struct kobject *kobj, struct kobject *parent,
312 const char *fmt, va_list vargs)
318 retval = kobject_set_name_vargs(kobj, fmt, aq);
321 printk(KERN_ERR "kobject: can not set name properly!\n");
324 kobj->parent = parent;
325 return kobject_add_internal(kobj);
329 * kobject_add - the main kobject add function
330 * @kobj: the kobject to add
331 * @parent: pointer to the parent of the kobject.
332 * @fmt: format to name the kobject with.
334 * The kobject name is set and added to the kobject hierarchy in this
337 * If @parent is set, then the parent of the @kobj will be set to it.
338 * If @parent is NULL, then the parent of the @kobj will be set to the
339 * kobject associted with the kset assigned to this kobject. If no kset
340 * is assigned to the kobject, then the kobject will be located in the
341 * root of the sysfs tree.
343 * If this function returns an error, kobject_put() must be called to
344 * properly clean up the memory associated with the object.
345 * Under no instance should the kobject that is passed to this function
346 * be directly freed with a call to kfree(), that can leak memory.
348 * Note, no "add" uevent will be created with this call, the caller should set
349 * up all of the necessary sysfs files for the object and then call
350 * kobject_uevent() with the UEVENT_ADD parameter to ensure that
351 * userspace is properly notified of this kobject's creation.
353 int kobject_add(struct kobject *kobj, struct kobject *parent,
354 const char *fmt, ...)
362 if (!kobj->state_initialized) {
363 printk(KERN_ERR "kobject '%s' (%p): tried to add an "
364 "uninitialized object, something is seriously wrong.\n",
365 kobject_name(kobj), kobj);
370 retval = kobject_add_varg(kobj, parent, fmt, args);
375 EXPORT_SYMBOL(kobject_add);
378 * kobject_init_and_add - initialize a kobject structure and add it to the kobject hierarchy
379 * @kobj: pointer to the kobject to initialize
380 * @ktype: pointer to the ktype for this kobject.
381 * @parent: pointer to the parent of this kobject.
382 * @fmt: the name of the kobject.
384 * This function combines the call to kobject_init() and
385 * kobject_add(). The same type of error handling after a call to
386 * kobject_add() and kobject lifetime rules are the same here.
388 int kobject_init_and_add(struct kobject *kobj, struct kobj_type *ktype,
389 struct kobject *parent, const char *fmt, ...)
394 kobject_init(kobj, ktype);
397 retval = kobject_add_varg(kobj, parent, fmt, args);
402 EXPORT_SYMBOL_GPL(kobject_init_and_add);
405 * kobject_rename - change the name of an object
406 * @kobj: object in question.
407 * @new_name: object's new name
410 int kobject_rename(struct kobject * kobj, const char *new_name)
413 const char *devpath = NULL;
414 char *devpath_string = NULL;
417 kobj = kobject_get(kobj);
423 /* see if this name is already in use */
425 struct kobject *temp_kobj;
426 temp_kobj = kset_find_obj(kobj->kset, new_name);
428 printk(KERN_WARNING "kobject '%s' cannot be renamed "
429 "to '%s' as '%s' is already in existence.\n",
430 kobject_name(kobj), new_name, new_name);
431 kobject_put(temp_kobj);
436 devpath = kobject_get_path(kobj, GFP_KERNEL);
441 devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
442 if (!devpath_string) {
446 sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
447 envp[0] = devpath_string;
450 error = sysfs_rename_dir(kobj, new_name);
452 /* This function is mostly/only used for network interface.
453 * Some hotplug package track interfaces by their name and
454 * therefore want to know when the name is changed by the user. */
456 kobject_uevent_env(kobj, KOBJ_MOVE, envp);
459 kfree(devpath_string);
467 * kobject_move - move object to another parent
468 * @kobj: object in question.
469 * @new_parent: object's new parent (can be NULL)
472 int kobject_move(struct kobject *kobj, struct kobject *new_parent)
475 struct kobject *old_parent;
476 const char *devpath = NULL;
477 char *devpath_string = NULL;
480 kobj = kobject_get(kobj);
483 new_parent = kobject_get(new_parent);
486 new_parent = kobject_get(&kobj->kset->kobj);
488 /* old object path */
489 devpath = kobject_get_path(kobj, GFP_KERNEL);
494 devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
495 if (!devpath_string) {
499 sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
500 envp[0] = devpath_string;
502 error = sysfs_move_dir(kobj, new_parent);
505 old_parent = kobj->parent;
506 kobj->parent = new_parent;
508 kobject_put(old_parent);
509 kobject_uevent_env(kobj, KOBJ_MOVE, envp);
511 kobject_put(new_parent);
513 kfree(devpath_string);
519 * kobject_del - unlink kobject from hierarchy.
523 void kobject_del(struct kobject * kobj)
528 sysfs_remove_dir(kobj);
529 kobj->state_in_sysfs = 0;
530 kobj_kset_leave(kobj);
531 kobject_put(kobj->parent);
536 * kobject_unregister - remove object from hierarchy and decrement refcount.
537 * @kobj: object going away.
540 void kobject_unregister(struct kobject * kobj)
544 pr_debug("kobject: '%s' (%p): %s\n",
545 kobject_name(kobj), kobj, __FUNCTION__);
546 kobject_uevent(kobj, KOBJ_REMOVE);
552 * kobject_get - increment refcount for object.
556 struct kobject * kobject_get(struct kobject * kobj)
559 kref_get(&kobj->kref);
564 * kobject_cleanup - free kobject resources.
565 * @kobj: object to cleanup
567 static void kobject_cleanup(struct kobject *kobj)
569 struct kobj_type *t = get_ktype(kobj);
570 const char *name = kobj->k_name;
571 int name_set = kobj->state_name_set;
573 pr_debug("kobject: '%s' (%p): %s\n",
574 kobject_name(kobj), kobj, __FUNCTION__);
576 if (t && !t->release)
577 pr_debug("kobject: '%s' (%p): does not have a release() "
578 "function, it is broken and must be fixed.\n",
579 kobject_name(kobj), kobj);
581 /* send "remove" if the caller did not do it but sent "add" */
582 if (kobj->state_add_uevent_sent && !kobj->state_remove_uevent_sent) {
583 pr_debug("kobject: '%s' (%p): auto cleanup 'remove' event\n",
584 kobject_name(kobj), kobj);
585 kobject_uevent(kobj, KOBJ_REMOVE);
588 /* remove from sysfs if the caller did not do it */
589 if (kobj->state_in_sysfs) {
590 pr_debug("kobject: '%s' (%p): auto cleanup kobject_del\n",
591 kobject_name(kobj), kobj);
595 if (t && t->release) {
596 pr_debug("kobject: '%s' (%p): calling ktype release\n",
597 kobject_name(kobj), kobj);
601 /* free name if we allocated it */
602 if (name_set && name) {
603 pr_debug("kobject: '%s': free name\n", name);
608 static void kobject_release(struct kref *kref)
610 kobject_cleanup(container_of(kref, struct kobject, kref));
614 * kobject_put - decrement refcount for object.
617 * Decrement the refcount, and if 0, call kobject_cleanup().
619 void kobject_put(struct kobject * kobj)
622 kref_put(&kobj->kref, kobject_release);
625 static void dynamic_kobj_release(struct kobject *kobj)
627 pr_debug("kobject: (%p): %s\n", kobj, __FUNCTION__);
631 static struct kobj_type dynamic_kobj_ktype = {
632 .release = dynamic_kobj_release,
633 .sysfs_ops = &kobj_sysfs_ops,
637 * kobject_create - create a struct kobject dynamically
639 * This function creates a kobject structure dynamically and sets it up
640 * to be a "dynamic" kobject with a default release function set up.
642 * If the kobject was not able to be created, NULL will be returned.
643 * The kobject structure returned from here must be cleaned up with a
644 * call to kobject_put() and not kfree(), as kobject_init() has
645 * already been called on this structure.
647 struct kobject *kobject_create(void)
649 struct kobject *kobj;
651 kobj = kzalloc(sizeof(*kobj), GFP_KERNEL);
655 kobject_init(kobj, &dynamic_kobj_ktype);
660 * kobject_create_and_add - create a struct kobject dynamically and register it with sysfs
662 * @name: the name for the kset
663 * @parent: the parent kobject of this kobject, if any.
665 * This function creates a kset structure dynamically and registers it
666 * with sysfs. When you are finished with this structure, call
667 * kobject_unregister() and the structure will be dynamically freed when
668 * it is no longer being used.
670 * If the kobject was not able to be created, NULL will be returned.
672 struct kobject *kobject_create_and_add(const char *name, struct kobject *parent)
674 struct kobject *kobj;
677 kobj = kobject_create();
681 retval = kobject_add(kobj, parent, "%s", name);
683 printk(KERN_WARNING "%s: kobject_add error: %d\n",
684 __FUNCTION__, retval);
690 EXPORT_SYMBOL_GPL(kobject_create_and_add);
693 * kset_init - initialize a kset for use
697 void kset_init(struct kset * k)
699 kobject_init_internal(&k->kobj);
700 INIT_LIST_HEAD(&k->list);
701 spin_lock_init(&k->list_lock);
704 /* default kobject attribute operations */
705 static ssize_t kobj_attr_show(struct kobject *kobj, struct attribute *attr,
708 struct kobj_attribute *kattr;
711 kattr = container_of(attr, struct kobj_attribute, attr);
713 ret = kattr->show(kobj, kattr, buf);
717 static ssize_t kobj_attr_store(struct kobject *kobj, struct attribute *attr,
718 const char *buf, size_t count)
720 struct kobj_attribute *kattr;
723 kattr = container_of(attr, struct kobj_attribute, attr);
725 ret = kattr->store(kobj, kattr, buf, count);
729 struct sysfs_ops kobj_sysfs_ops = {
730 .show = kobj_attr_show,
731 .store = kobj_attr_store,
735 * kset_register - initialize and add a kset.
739 int kset_register(struct kset * k)
747 err = kobject_add_internal(&k->kobj);
750 kobject_uevent(&k->kobj, KOBJ_ADD);
756 * kset_unregister - remove a kset.
760 void kset_unregister(struct kset * k)
764 kobject_unregister(&k->kobj);
769 * kset_find_obj - search for object in kset.
770 * @kset: kset we're looking in.
771 * @name: object's name.
773 * Lock kset via @kset->subsys, and iterate over @kset->list,
774 * looking for a matching kobject. If matching object is found
775 * take a reference and return the object.
778 struct kobject * kset_find_obj(struct kset * kset, const char * name)
780 struct list_head * entry;
781 struct kobject * ret = NULL;
783 spin_lock(&kset->list_lock);
784 list_for_each(entry,&kset->list) {
785 struct kobject * k = to_kobj(entry);
786 if (kobject_name(k) && !strcmp(kobject_name(k),name)) {
787 ret = kobject_get(k);
791 spin_unlock(&kset->list_lock);
795 static void kset_release(struct kobject *kobj)
797 struct kset *kset = container_of(kobj, struct kset, kobj);
798 pr_debug("kobject: '%s' (%p): %s\n",
799 kobject_name(kobj), kobj, __FUNCTION__);
803 static struct kobj_type kset_ktype = {
804 .sysfs_ops = &kobj_sysfs_ops,
805 .release = kset_release,
809 * kset_create - create a struct kset dynamically
811 * @name: the name for the kset
812 * @uevent_ops: a struct kset_uevent_ops for the kset
813 * @parent_kobj: the parent kobject of this kset, if any.
815 * This function creates a kset structure dynamically. This structure can
816 * then be registered with the system and show up in sysfs with a call to
817 * kset_register(). When you are finished with this structure, if
818 * kset_register() has been called, call kset_unregister() and the
819 * structure will be dynamically freed when it is no longer being used.
821 * If the kset was not able to be created, NULL will be returned.
823 static struct kset *kset_create(const char *name,
824 struct kset_uevent_ops *uevent_ops,
825 struct kobject *parent_kobj)
829 kset = kzalloc(sizeof(*kset), GFP_KERNEL);
832 kobject_set_name(&kset->kobj, name);
833 kset->uevent_ops = uevent_ops;
834 kset->kobj.parent = parent_kobj;
837 * The kobject of this kset will have a type of kset_ktype and belong to
838 * no kset itself. That way we can properly free it when it is
839 * finished being used.
841 kset->kobj.ktype = &kset_ktype;
842 kset->kobj.kset = NULL;
848 * kset_create_and_add - create a struct kset dynamically and add it to sysfs
850 * @name: the name for the kset
851 * @uevent_ops: a struct kset_uevent_ops for the kset
852 * @parent_kobj: the parent kobject of this kset, if any.
854 * This function creates a kset structure dynamically and registers it
855 * with sysfs. When you are finished with this structure, call
856 * kset_unregister() and the structure will be dynamically freed when it
857 * is no longer being used.
859 * If the kset was not able to be created, NULL will be returned.
861 struct kset *kset_create_and_add(const char *name,
862 struct kset_uevent_ops *uevent_ops,
863 struct kobject *parent_kobj)
868 kset = kset_create(name, uevent_ops, parent_kobj);
871 error = kset_register(kset);
878 EXPORT_SYMBOL_GPL(kset_create_and_add);
880 EXPORT_SYMBOL(kobject_unregister);
881 EXPORT_SYMBOL(kobject_get);
882 EXPORT_SYMBOL(kobject_put);
883 EXPORT_SYMBOL(kobject_del);
885 EXPORT_SYMBOL(kset_register);
886 EXPORT_SYMBOL(kset_unregister);