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("%s: path = '%s'\n",__FUNCTION__,path);
102 * kobject_get_path - generate and return the path associated with a given kobj and kset pair.
104 * @kobj: kobject in question, with which to build the path
105 * @gfp_mask: the allocation type used to allocate the path
107 * The result must be freed by the caller with kfree().
109 char *kobject_get_path(struct kobject *kobj, gfp_t gfp_mask)
114 len = get_kobj_path_length(kobj);
117 path = kzalloc(len, gfp_mask);
120 fill_kobj_path(kobj, path, len);
124 EXPORT_SYMBOL_GPL(kobject_get_path);
127 * kobject_init - initialize object.
128 * @kobj: object in question.
130 void kobject_init(struct kobject * kobj)
134 kref_init(&kobj->kref);
135 INIT_LIST_HEAD(&kobj->entry);
136 kobj->kset = kset_get(kobj->kset);
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() on error.
150 static void unlink(struct kobject * kobj)
153 spin_lock(&kobj->kset->list_lock);
154 list_del_init(&kobj->entry);
155 spin_unlock(&kobj->kset->list_lock);
161 * kobject_add - add an object to the hierarchy.
165 int kobject_add(struct kobject * kobj)
168 struct kobject * parent;
170 if (!(kobj = kobject_get(kobj)))
173 kobject_set_name(kobj, "NO_NAME");
174 if (!*kobj->k_name) {
175 pr_debug("kobject attempted to be registered with no name!\n");
180 parent = kobject_get(kobj->parent);
182 pr_debug("kobject %s: registering. parent: %s, set: %s\n",
183 kobject_name(kobj), parent ? kobject_name(parent) : "<NULL>",
184 kobj->kset ? kobject_name(&kobj->kset->kobj) : "<NULL>" );
187 spin_lock(&kobj->kset->list_lock);
190 parent = kobject_get(&kobj->kset->kobj);
192 * If the kset is our parent, get a second
193 * reference, we drop both the kset and the
194 * parent ref on cleanup
199 list_add_tail(&kobj->entry,&kobj->kset->list);
200 spin_unlock(&kobj->kset->list_lock);
201 kobj->parent = parent;
204 error = create_dir(kobj);
206 /* unlink does the kobject_put() for us */
210 /* be noisy on error issues */
211 if (error == -EEXIST)
212 printk(KERN_ERR "kobject_add failed for %s with "
213 "-EEXIST, don't try to register things with "
214 "the same name in the same directory.\n",
217 printk(KERN_ERR "kobject_add failed for %s (%d)\n",
218 kobject_name(kobj), error);
226 * kobject_register - initialize and add an object.
227 * @kobj: object in question.
230 int kobject_register(struct kobject * kobj)
235 error = kobject_add(kobj);
237 kobject_uevent(kobj, KOBJ_ADD);
243 * kobject_set_name_vargs - Set the name of an kobject
244 * @kobj: struct kobject to set the name of
245 * @fmt: format string used to build the name
246 * @vargs: vargs to format the string.
248 static int kobject_set_name_vargs(struct kobject *kobj, const char *fmt,
255 name = kvasprintf(GFP_KERNEL, fmt, vargs);
261 /* Free the old name, if necessary. */
264 /* Now, set the new name */
271 * kobject_set_name - Set the name of a kobject
272 * @kobj: struct kobject to set the name of
273 * @fmt: format string used to build the name
275 * This sets the name of the kobject. If you have already added the
276 * kobject to the system, you must call kobject_rename() in order to
277 * change the name of the kobject.
279 int kobject_set_name(struct kobject *kobj, const char *fmt, ...)
285 retval = kobject_set_name_vargs(kobj, fmt, args);
290 EXPORT_SYMBOL(kobject_set_name);
293 * kobject_init_ng - initialize a kobject structure
294 * @kobj: pointer to the kobject to initialize
295 * @ktype: pointer to the ktype for this kobject.
297 * This function will properly initialize a kobject such that it can then
298 * be passed to the kobject_add() call.
300 * After this function is called, the kobject MUST be cleaned up by a call
301 * to kobject_put(), not by a call to kfree directly to ensure that all of
302 * the memory is cleaned up properly.
304 void kobject_init_ng(struct kobject *kobj, struct kobj_type *ktype)
309 err_str = "invalid kobject pointer!";
313 err_str = "must have a ktype to be initialized properly!\n";
316 if (atomic_read(&kobj->kref.refcount)) {
317 /* do not error out as sometimes we can recover */
318 printk(KERN_ERR "kobject: reference count is already set, "
319 "something is seriously wrong.\n");
323 kref_init(&kobj->kref);
324 INIT_LIST_HEAD(&kobj->entry);
329 printk(KERN_ERR "kobject: %s\n", err_str);
332 EXPORT_SYMBOL(kobject_init_ng);
334 static int kobject_add_varg(struct kobject *kobj, struct kobject *parent,
335 const char *fmt, va_list vargs)
341 retval = kobject_set_name_vargs(kobj, fmt, aq);
344 printk(KERN_ERR "kobject: can not set name properly!\n");
347 kobj->parent = parent;
348 return kobject_add(kobj);
352 * kobject_add_ng - the main kobject add function
353 * @kobj: the kobject to add
354 * @parent: pointer to the parent of the kobject.
355 * @fmt: format to name the kobject with.
357 * The kobject name is set and added to the kobject hierarchy in this
360 * If @parent is set, then the parent of the @kobj will be set to it.
361 * If @parent is NULL, then the parent of the @kobj will be set to the
362 * kobject associted with the kset assigned to this kobject. If no kset
363 * is assigned to the kobject, then the kobject will be located in the
364 * root of the sysfs tree.
366 * If this function returns an error, kobject_put() must be called to
367 * properly clean up the memory associated with the object.
369 * If the function is successful, the only way to properly clean up the
370 * memory is with a call to kobject_del(), in which case, a call to
371 * kobject_put() is not necessary (kobject_del() does the final
372 * kobject_put() to call the release function in the ktype's release
375 * Under no instance should the kobject that is passed to this function
376 * be directly freed with a call to kfree(), that can leak memory.
378 * Note, no uevent will be created with this call, the caller should set
379 * up all of the necessary sysfs files for the object and then call
380 * kobject_uevent() with the UEVENT_ADD parameter to ensure that
381 * userspace is properly notified of this kobject's creation.
383 int kobject_add_ng(struct kobject *kobj, struct kobject *parent,
384 const char *fmt, ...)
393 retval = kobject_add_varg(kobj, parent, fmt, args);
398 EXPORT_SYMBOL(kobject_add_ng);
401 * kobject_init_and_add - initialize a kobject structure and add it to the kobject hierarchy
402 * @kobj: pointer to the kobject to initialize
403 * @ktype: pointer to the ktype for this kobject.
404 * @parent: pointer to the parent of this kobject.
405 * @fmt: the name of the kobject.
407 * This function combines the call to kobject_init_ng() and
408 * kobject_add_ng(). The same type of error handling after a call to
409 * kobject_add_ng() and kobject lifetime rules are the same here.
411 int kobject_init_and_add(struct kobject *kobj, struct kobj_type *ktype,
412 struct kobject *parent, const char *fmt, ...)
417 kobject_init_ng(kobj, ktype);
420 retval = kobject_add_varg(kobj, parent, fmt, args);
425 EXPORT_SYMBOL_GPL(kobject_init_and_add);
428 * kobject_rename - change the name of an object
429 * @kobj: object in question.
430 * @new_name: object's new name
433 int kobject_rename(struct kobject * kobj, const char *new_name)
436 const char *devpath = NULL;
437 char *devpath_string = NULL;
440 kobj = kobject_get(kobj);
446 /* see if this name is already in use */
448 struct kobject *temp_kobj;
449 temp_kobj = kset_find_obj(kobj->kset, new_name);
451 printk(KERN_WARNING "kobject '%s' cannot be renamed "
452 "to '%s' as '%s' is already in existence.\n",
453 kobject_name(kobj), new_name, new_name);
454 kobject_put(temp_kobj);
459 devpath = kobject_get_path(kobj, GFP_KERNEL);
464 devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
465 if (!devpath_string) {
469 sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
470 envp[0] = devpath_string;
473 error = sysfs_rename_dir(kobj, new_name);
475 /* This function is mostly/only used for network interface.
476 * Some hotplug package track interfaces by their name and
477 * therefore want to know when the name is changed by the user. */
479 kobject_uevent_env(kobj, KOBJ_MOVE, envp);
482 kfree(devpath_string);
490 * kobject_move - move object to another parent
491 * @kobj: object in question.
492 * @new_parent: object's new parent (can be NULL)
495 int kobject_move(struct kobject *kobj, struct kobject *new_parent)
498 struct kobject *old_parent;
499 const char *devpath = NULL;
500 char *devpath_string = NULL;
503 kobj = kobject_get(kobj);
506 new_parent = kobject_get(new_parent);
509 new_parent = kobject_get(&kobj->kset->kobj);
511 /* old object path */
512 devpath = kobject_get_path(kobj, GFP_KERNEL);
517 devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
518 if (!devpath_string) {
522 sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
523 envp[0] = devpath_string;
525 error = sysfs_move_dir(kobj, new_parent);
528 old_parent = kobj->parent;
529 kobj->parent = new_parent;
531 kobject_put(old_parent);
532 kobject_uevent_env(kobj, KOBJ_MOVE, envp);
534 kobject_put(new_parent);
536 kfree(devpath_string);
542 * kobject_del - unlink kobject from hierarchy.
546 void kobject_del(struct kobject * kobj)
550 sysfs_remove_dir(kobj);
555 * kobject_unregister - remove object from hierarchy and decrement refcount.
556 * @kobj: object going away.
559 void kobject_unregister(struct kobject * kobj)
563 pr_debug("kobject %s: unregistering\n",kobject_name(kobj));
564 kobject_uevent(kobj, KOBJ_REMOVE);
570 * kobject_get - increment refcount for object.
574 struct kobject * kobject_get(struct kobject * kobj)
577 kref_get(&kobj->kref);
582 * kobject_cleanup - free kobject resources.
583 * @kobj: object to cleanup
585 static void kobject_cleanup(struct kobject *kobj)
587 struct kobj_type * t = get_ktype(kobj);
588 struct kset * s = kobj->kset;
589 struct kobject * parent = kobj->parent;
590 const char *name = kobj->k_name;
592 pr_debug("kobject %s: cleaning up\n",kobject_name(kobj));
593 if (t && t->release) {
595 /* If we have a release function, we can guess that this was
596 * not a statically allocated kobject, so we should be safe to
605 static void kobject_release(struct kref *kref)
607 kobject_cleanup(container_of(kref, struct kobject, kref));
611 * kobject_put - decrement refcount for object.
614 * Decrement the refcount, and if 0, call kobject_cleanup().
616 void kobject_put(struct kobject * kobj)
619 kref_put(&kobj->kref, kobject_release);
622 static void dynamic_kobj_release(struct kobject *kobj)
624 pr_debug("%s: freeing %s\n", __FUNCTION__, kobject_name(kobj));
628 static struct kobj_type dynamic_kobj_ktype = {
629 .release = dynamic_kobj_release,
633 * kobject_create - create a struct kobject dynamically
635 * This function creates a kobject structure dynamically and sets it up
636 * to be a "dynamic" kobject with a default release function set up.
638 * If the kobject was not able to be created, NULL will be returned.
639 * The kobject structure returned from here must be cleaned up with a
640 * call to kobject_put() and not kfree(), as kobject_init_ng() has
641 * already been called on this structure.
643 struct kobject *kobject_create(void)
645 struct kobject *kobj;
647 kobj = kzalloc(sizeof(*kobj), GFP_KERNEL);
651 kobject_init_ng(kobj, &dynamic_kobj_ktype);
656 * kobject_create_and_add - create a struct kobject dynamically and register it with sysfs
658 * @name: the name for the kset
659 * @parent: the parent kobject of this kobject, if any.
661 * This function creates a kset structure dynamically and registers it
662 * with sysfs. When you are finished with this structure, call
663 * kobject_unregister() and the structure will be dynamically freed when
664 * it is no longer being used.
666 * If the kobject was not able to be created, NULL will be returned.
668 struct kobject *kobject_create_and_add(const char *name, struct kobject *parent)
670 struct kobject *kobj;
673 kobj = kobject_create();
677 retval = kobject_add_ng(kobj, parent, "%s", name);
679 printk(KERN_WARNING "%s: kobject_add error: %d\n",
680 __FUNCTION__, retval);
686 EXPORT_SYMBOL_GPL(kobject_create_and_add);
689 * kset_init - initialize a kset for use
693 void kset_init(struct kset * k)
695 kobject_init(&k->kobj);
696 INIT_LIST_HEAD(&k->list);
697 spin_lock_init(&k->list_lock);
700 /* default kobject attribute operations */
701 static ssize_t kobj_attr_show(struct kobject *kobj, struct attribute *attr,
704 struct kobj_attribute *kattr;
707 kattr = container_of(attr, struct kobj_attribute, attr);
709 ret = kattr->show(kobj, kattr, buf);
713 static ssize_t kobj_attr_store(struct kobject *kobj, struct attribute *attr,
714 const char *buf, size_t count)
716 struct kobj_attribute *kattr;
719 kattr = container_of(attr, struct kobj_attribute, attr);
721 ret = kattr->store(kobj, kattr, buf, count);
725 struct sysfs_ops kobj_sysfs_ops = {
726 .show = kobj_attr_show,
727 .store = kobj_attr_store,
731 * kset_add - add a kset object to the hierarchy.
735 int kset_add(struct kset * k)
737 return kobject_add(&k->kobj);
742 * kset_register - initialize and add a kset.
746 int kset_register(struct kset * k)
757 kobject_uevent(&k->kobj, KOBJ_ADD);
763 * kset_unregister - remove a kset.
767 void kset_unregister(struct kset * k)
771 kobject_unregister(&k->kobj);
776 * kset_find_obj - search for object in kset.
777 * @kset: kset we're looking in.
778 * @name: object's name.
780 * Lock kset via @kset->subsys, and iterate over @kset->list,
781 * looking for a matching kobject. If matching object is found
782 * take a reference and return the object.
785 struct kobject * kset_find_obj(struct kset * kset, const char * name)
787 struct list_head * entry;
788 struct kobject * ret = NULL;
790 spin_lock(&kset->list_lock);
791 list_for_each(entry,&kset->list) {
792 struct kobject * k = to_kobj(entry);
793 if (kobject_name(k) && !strcmp(kobject_name(k),name)) {
794 ret = kobject_get(k);
798 spin_unlock(&kset->list_lock);
802 int subsystem_register(struct kset *s)
804 return kset_register(s);
807 void subsystem_unregister(struct kset *s)
813 * subsystem_create_file - export sysfs attribute file.
815 * @a: subsystem attribute descriptor.
818 int subsys_create_file(struct kset *s, struct subsys_attribute *a)
826 error = sysfs_create_file(&s->kobj, &a->attr);
832 static void kset_release(struct kobject *kobj)
834 struct kset *kset = container_of(kobj, struct kset, kobj);
835 pr_debug("kset %s: now freed\n", kobject_name(kobj));
839 static struct kobj_type kset_type = {
840 .release = kset_release,
844 * kset_create - create a struct kset dynamically
846 * @name: the name for the kset
847 * @uevent_ops: a struct kset_uevent_ops for the kset
848 * @parent_kobj: the parent kobject of this kset, if any.
850 * This function creates a kset structure dynamically. This structure can
851 * then be registered with the system and show up in sysfs with a call to
852 * kset_register(). When you are finished with this structure, if
853 * kset_register() has been called, call kset_unregister() and the
854 * structure will be dynamically freed when it is no longer being used.
856 * If the kset was not able to be created, NULL will be returned.
858 static struct kset *kset_create(const char *name,
859 struct kset_uevent_ops *uevent_ops,
860 struct kobject *parent_kobj)
864 kset = kzalloc(sizeof(*kset), GFP_KERNEL);
867 kobject_set_name(&kset->kobj, name);
868 kset->uevent_ops = uevent_ops;
869 kset->kobj.parent = parent_kobj;
872 * The kobject of this kset will have a type of kset_type and belong to
873 * no kset itself. That way we can properly free it when it is
874 * finished being used.
876 kset->kobj.ktype = &kset_type;
877 kset->kobj.kset = NULL;
883 * kset_create_and_add - create a struct kset dynamically and add it to sysfs
885 * @name: the name for the kset
886 * @uevent_ops: a struct kset_uevent_ops for the kset
887 * @parent_kobj: the parent kobject of this kset, if any.
889 * This function creates a kset structure dynamically and registers it
890 * with sysfs. When you are finished with this structure, call
891 * kset_unregister() and the structure will be dynamically freed when it
892 * is no longer being used.
894 * If the kset was not able to be created, NULL will be returned.
896 struct kset *kset_create_and_add(const char *name,
897 struct kset_uevent_ops *uevent_ops,
898 struct kobject *parent_kobj)
903 kset = kset_create(name, uevent_ops, parent_kobj);
906 error = kset_register(kset);
913 EXPORT_SYMBOL_GPL(kset_create_and_add);
915 EXPORT_SYMBOL(kobject_init);
916 EXPORT_SYMBOL(kobject_register);
917 EXPORT_SYMBOL(kobject_unregister);
918 EXPORT_SYMBOL(kobject_get);
919 EXPORT_SYMBOL(kobject_put);
920 EXPORT_SYMBOL(kobject_add);
921 EXPORT_SYMBOL(kobject_del);
923 EXPORT_SYMBOL(kset_register);
924 EXPORT_SYMBOL(kset_unregister);
926 EXPORT_SYMBOL(subsystem_register);
927 EXPORT_SYMBOL(subsystem_unregister);
928 EXPORT_SYMBOL(subsys_create_file);