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() 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);
165 * kobject_add - add an object to the hierarchy.
169 int kobject_add(struct kobject * kobj)
172 struct kobject * parent;
174 if (!(kobj = kobject_get(kobj)))
177 kobject_set_name(kobj, "NO_NAME");
178 if (!*kobj->k_name) {
179 pr_debug("kobject (%p) attempted to be registered with no "
185 parent = kobject_get(kobj->parent);
187 pr_debug("kobject: '%s' (%p): %s: parent: '%s', set: '%s'\n",
188 kobject_name(kobj), kobj, __FUNCTION__,
189 parent ? kobject_name(parent) : "<NULL>",
190 kobj->kset ? kobject_name(&kobj->kset->kobj) : "<NULL>" );
193 kobj->kset = kset_get(kobj->kset);
196 parent = kobject_get(&kobj->kset->kobj);
198 * If the kset is our parent, get a second
199 * reference, we drop both the kset and the
200 * parent ref on cleanup
205 spin_lock(&kobj->kset->list_lock);
206 list_add_tail(&kobj->entry, &kobj->kset->list);
207 spin_unlock(&kobj->kset->list_lock);
208 kobj->parent = parent;
211 error = create_dir(kobj);
213 /* unlink does the kobject_put() for us */
216 /* be noisy on error issues */
217 if (error == -EEXIST)
218 printk(KERN_ERR "kobject_add failed for %s with "
219 "-EEXIST, don't try to register things with "
220 "the same name in the same directory.\n",
223 printk(KERN_ERR "kobject_add failed for %s (%d)\n",
224 kobject_name(kobj), error);
232 * kobject_register - initialize and add an object.
233 * @kobj: object in question.
236 int kobject_register(struct kobject * kobj)
241 error = kobject_add(kobj);
243 kobject_uevent(kobj, KOBJ_ADD);
249 * kobject_set_name_vargs - Set the name of an kobject
250 * @kobj: struct kobject to set the name of
251 * @fmt: format string used to build the name
252 * @vargs: vargs to format the string.
254 static int kobject_set_name_vargs(struct kobject *kobj, const char *fmt,
261 name = kvasprintf(GFP_KERNEL, fmt, vargs);
267 /* Free the old name, if necessary. */
270 /* Now, set the new name */
277 * kobject_set_name - Set the name of a kobject
278 * @kobj: struct kobject to set the name of
279 * @fmt: format string used to build the name
281 * This sets the name of the kobject. If you have already added the
282 * kobject to the system, you must call kobject_rename() in order to
283 * change the name of the kobject.
285 int kobject_set_name(struct kobject *kobj, const char *fmt, ...)
291 retval = kobject_set_name_vargs(kobj, fmt, args);
296 EXPORT_SYMBOL(kobject_set_name);
299 * kobject_init_ng - initialize a kobject structure
300 * @kobj: pointer to the kobject to initialize
301 * @ktype: pointer to the ktype for this kobject.
303 * This function will properly initialize a kobject such that it can then
304 * be passed to the kobject_add() call.
306 * After this function is called, the kobject MUST be cleaned up by a call
307 * to kobject_put(), not by a call to kfree directly to ensure that all of
308 * the memory is cleaned up properly.
310 void kobject_init_ng(struct kobject *kobj, struct kobj_type *ktype)
315 err_str = "invalid kobject pointer!";
319 err_str = "must have a ktype to be initialized properly!\n";
322 if (atomic_read(&kobj->kref.refcount)) {
323 /* do not error out as sometimes we can recover */
324 printk(KERN_ERR "kobject: reference count is already set, "
325 "something is seriously wrong.\n");
329 kref_init(&kobj->kref);
330 INIT_LIST_HEAD(&kobj->entry);
335 printk(KERN_ERR "kobject: %s\n", err_str);
338 EXPORT_SYMBOL(kobject_init_ng);
340 static int kobject_add_varg(struct kobject *kobj, struct kobject *parent,
341 const char *fmt, va_list vargs)
347 retval = kobject_set_name_vargs(kobj, fmt, aq);
350 printk(KERN_ERR "kobject: can not set name properly!\n");
353 kobj->parent = parent;
354 return kobject_add(kobj);
358 * kobject_add_ng - the main kobject add function
359 * @kobj: the kobject to add
360 * @parent: pointer to the parent of the kobject.
361 * @fmt: format to name the kobject with.
363 * The kobject name is set and added to the kobject hierarchy in this
366 * If @parent is set, then the parent of the @kobj will be set to it.
367 * If @parent is NULL, then the parent of the @kobj will be set to the
368 * kobject associted with the kset assigned to this kobject. If no kset
369 * is assigned to the kobject, then the kobject will be located in the
370 * root of the sysfs tree.
372 * If this function returns an error, kobject_put() must be called to
373 * properly clean up the memory associated with the object.
375 * If the function is successful, the only way to properly clean up the
376 * memory is with a call to kobject_del(), in which case, a call to
377 * kobject_put() is not necessary (kobject_del() does the final
378 * kobject_put() to call the release function in the ktype's release
381 * Under no instance should the kobject that is passed to this function
382 * be directly freed with a call to kfree(), that can leak memory.
384 * Note, no uevent will be created with this call, the caller should set
385 * up all of the necessary sysfs files for the object and then call
386 * kobject_uevent() with the UEVENT_ADD parameter to ensure that
387 * userspace is properly notified of this kobject's creation.
389 int kobject_add_ng(struct kobject *kobj, struct kobject *parent,
390 const char *fmt, ...)
399 retval = kobject_add_varg(kobj, parent, fmt, args);
404 EXPORT_SYMBOL(kobject_add_ng);
407 * kobject_init_and_add - initialize a kobject structure and add it to the kobject hierarchy
408 * @kobj: pointer to the kobject to initialize
409 * @ktype: pointer to the ktype for this kobject.
410 * @parent: pointer to the parent of this kobject.
411 * @fmt: the name of the kobject.
413 * This function combines the call to kobject_init_ng() and
414 * kobject_add_ng(). The same type of error handling after a call to
415 * kobject_add_ng() and kobject lifetime rules are the same here.
417 int kobject_init_and_add(struct kobject *kobj, struct kobj_type *ktype,
418 struct kobject *parent, const char *fmt, ...)
423 kobject_init_ng(kobj, ktype);
426 retval = kobject_add_varg(kobj, parent, fmt, args);
431 EXPORT_SYMBOL_GPL(kobject_init_and_add);
434 * kobject_rename - change the name of an object
435 * @kobj: object in question.
436 * @new_name: object's new name
439 int kobject_rename(struct kobject * kobj, const char *new_name)
442 const char *devpath = NULL;
443 char *devpath_string = NULL;
446 kobj = kobject_get(kobj);
452 /* see if this name is already in use */
454 struct kobject *temp_kobj;
455 temp_kobj = kset_find_obj(kobj->kset, new_name);
457 printk(KERN_WARNING "kobject '%s' cannot be renamed "
458 "to '%s' as '%s' is already in existence.\n",
459 kobject_name(kobj), new_name, new_name);
460 kobject_put(temp_kobj);
465 devpath = kobject_get_path(kobj, GFP_KERNEL);
470 devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
471 if (!devpath_string) {
475 sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
476 envp[0] = devpath_string;
479 error = sysfs_rename_dir(kobj, new_name);
481 /* This function is mostly/only used for network interface.
482 * Some hotplug package track interfaces by their name and
483 * therefore want to know when the name is changed by the user. */
485 kobject_uevent_env(kobj, KOBJ_MOVE, envp);
488 kfree(devpath_string);
496 * kobject_move - move object to another parent
497 * @kobj: object in question.
498 * @new_parent: object's new parent (can be NULL)
501 int kobject_move(struct kobject *kobj, struct kobject *new_parent)
504 struct kobject *old_parent;
505 const char *devpath = NULL;
506 char *devpath_string = NULL;
509 kobj = kobject_get(kobj);
512 new_parent = kobject_get(new_parent);
515 new_parent = kobject_get(&kobj->kset->kobj);
517 /* old object path */
518 devpath = kobject_get_path(kobj, GFP_KERNEL);
523 devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
524 if (!devpath_string) {
528 sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
529 envp[0] = devpath_string;
531 error = sysfs_move_dir(kobj, new_parent);
534 old_parent = kobj->parent;
535 kobj->parent = new_parent;
537 kobject_put(old_parent);
538 kobject_uevent_env(kobj, KOBJ_MOVE, envp);
540 kobject_put(new_parent);
542 kfree(devpath_string);
548 * kobject_del - unlink kobject from hierarchy.
552 void kobject_del(struct kobject * kobj)
556 sysfs_remove_dir(kobj);
561 * kobject_unregister - remove object from hierarchy and decrement refcount.
562 * @kobj: object going away.
565 void kobject_unregister(struct kobject * kobj)
569 pr_debug("kobject: '%s' (%p): %s\n",
570 kobject_name(kobj), kobj, __FUNCTION__);
571 kobject_uevent(kobj, KOBJ_REMOVE);
577 * kobject_get - increment refcount for object.
581 struct kobject * kobject_get(struct kobject * kobj)
584 kref_get(&kobj->kref);
589 * kobject_cleanup - free kobject resources.
590 * @kobj: object to cleanup
592 static void kobject_cleanup(struct kobject *kobj)
594 struct kobj_type * t = get_ktype(kobj);
595 struct kset * s = kobj->kset;
596 const char *name = kobj->k_name;
598 pr_debug("kobject: '%s' (%p): %s\n",
599 kobject_name(kobj), kobj, __FUNCTION__);
600 if (t && t->release) {
602 /* If we have a release function, we can guess that this was
603 * not a statically allocated kobject, so we should be safe to
611 static void kobject_release(struct kref *kref)
613 kobject_cleanup(container_of(kref, struct kobject, kref));
617 * kobject_put - decrement refcount for object.
620 * Decrement the refcount, and if 0, call kobject_cleanup().
622 void kobject_put(struct kobject * kobj)
625 kref_put(&kobj->kref, kobject_release);
628 static void dynamic_kobj_release(struct kobject *kobj)
630 pr_debug("kobject: '%s' (%p): %s\n",
631 kobject_name(kobj), kobj, __FUNCTION__);
635 static struct kobj_type dynamic_kobj_ktype = {
636 .release = dynamic_kobj_release,
637 .sysfs_ops = &kobj_sysfs_ops,
641 * kobject_create - create a struct kobject dynamically
643 * This function creates a kobject structure dynamically and sets it up
644 * to be a "dynamic" kobject with a default release function set up.
646 * If the kobject was not able to be created, NULL will be returned.
647 * The kobject structure returned from here must be cleaned up with a
648 * call to kobject_put() and not kfree(), as kobject_init_ng() has
649 * already been called on this structure.
651 struct kobject *kobject_create(void)
653 struct kobject *kobj;
655 kobj = kzalloc(sizeof(*kobj), GFP_KERNEL);
659 kobject_init_ng(kobj, &dynamic_kobj_ktype);
664 * kobject_create_and_add - create a struct kobject dynamically and register it with sysfs
666 * @name: the name for the kset
667 * @parent: the parent kobject of this kobject, if any.
669 * This function creates a kset structure dynamically and registers it
670 * with sysfs. When you are finished with this structure, call
671 * kobject_unregister() and the structure will be dynamically freed when
672 * it is no longer being used.
674 * If the kobject was not able to be created, NULL will be returned.
676 struct kobject *kobject_create_and_add(const char *name, struct kobject *parent)
678 struct kobject *kobj;
681 kobj = kobject_create();
685 retval = kobject_add_ng(kobj, parent, "%s", name);
687 printk(KERN_WARNING "%s: kobject_add error: %d\n",
688 __FUNCTION__, retval);
694 EXPORT_SYMBOL_GPL(kobject_create_and_add);
697 * kset_init - initialize a kset for use
701 void kset_init(struct kset * k)
703 kobject_init(&k->kobj);
704 INIT_LIST_HEAD(&k->list);
705 spin_lock_init(&k->list_lock);
708 /* default kobject attribute operations */
709 static ssize_t kobj_attr_show(struct kobject *kobj, struct attribute *attr,
712 struct kobj_attribute *kattr;
715 kattr = container_of(attr, struct kobj_attribute, attr);
717 ret = kattr->show(kobj, kattr, buf);
721 static ssize_t kobj_attr_store(struct kobject *kobj, struct attribute *attr,
722 const char *buf, size_t count)
724 struct kobj_attribute *kattr;
727 kattr = container_of(attr, struct kobj_attribute, attr);
729 ret = kattr->store(kobj, kattr, buf, count);
733 struct sysfs_ops kobj_sysfs_ops = {
734 .show = kobj_attr_show,
735 .store = kobj_attr_store,
739 * kset_add - add a kset object to the hierarchy.
743 int kset_add(struct kset * k)
745 return kobject_add(&k->kobj);
750 * kset_register - initialize and add a kset.
754 int kset_register(struct kset * k)
765 kobject_uevent(&k->kobj, KOBJ_ADD);
771 * kset_unregister - remove a kset.
775 void kset_unregister(struct kset * k)
779 kobject_unregister(&k->kobj);
784 * kset_find_obj - search for object in kset.
785 * @kset: kset we're looking in.
786 * @name: object's name.
788 * Lock kset via @kset->subsys, and iterate over @kset->list,
789 * looking for a matching kobject. If matching object is found
790 * take a reference and return the object.
793 struct kobject * kset_find_obj(struct kset * kset, const char * name)
795 struct list_head * entry;
796 struct kobject * ret = NULL;
798 spin_lock(&kset->list_lock);
799 list_for_each(entry,&kset->list) {
800 struct kobject * k = to_kobj(entry);
801 if (kobject_name(k) && !strcmp(kobject_name(k),name)) {
802 ret = kobject_get(k);
806 spin_unlock(&kset->list_lock);
810 static void kset_release(struct kobject *kobj)
812 struct kset *kset = container_of(kobj, struct kset, kobj);
813 pr_debug("kobject: '%s' (%p): %s\n",
814 kobject_name(kobj), kobj, __FUNCTION__);
818 static struct kobj_type kset_ktype = {
819 .sysfs_ops = &kobj_sysfs_ops,
820 .release = kset_release,
824 * kset_create - create a struct kset dynamically
826 * @name: the name for the kset
827 * @uevent_ops: a struct kset_uevent_ops for the kset
828 * @parent_kobj: the parent kobject of this kset, if any.
830 * This function creates a kset structure dynamically. This structure can
831 * then be registered with the system and show up in sysfs with a call to
832 * kset_register(). When you are finished with this structure, if
833 * kset_register() has been called, call kset_unregister() and the
834 * structure will be dynamically freed when it is no longer being used.
836 * If the kset was not able to be created, NULL will be returned.
838 static struct kset *kset_create(const char *name,
839 struct kset_uevent_ops *uevent_ops,
840 struct kobject *parent_kobj)
844 kset = kzalloc(sizeof(*kset), GFP_KERNEL);
847 kobject_set_name(&kset->kobj, name);
848 kset->uevent_ops = uevent_ops;
849 kset->kobj.parent = parent_kobj;
852 * The kobject of this kset will have a type of kset_ktype and belong to
853 * no kset itself. That way we can properly free it when it is
854 * finished being used.
856 kset->kobj.ktype = &kset_ktype;
857 kset->kobj.kset = NULL;
863 * kset_create_and_add - create a struct kset dynamically and add it to sysfs
865 * @name: the name for the kset
866 * @uevent_ops: a struct kset_uevent_ops for the kset
867 * @parent_kobj: the parent kobject of this kset, if any.
869 * This function creates a kset structure dynamically and registers it
870 * with sysfs. When you are finished with this structure, call
871 * kset_unregister() and the structure will be dynamically freed when it
872 * is no longer being used.
874 * If the kset was not able to be created, NULL will be returned.
876 struct kset *kset_create_and_add(const char *name,
877 struct kset_uevent_ops *uevent_ops,
878 struct kobject *parent_kobj)
883 kset = kset_create(name, uevent_ops, parent_kobj);
886 error = kset_register(kset);
893 EXPORT_SYMBOL_GPL(kset_create_and_add);
895 EXPORT_SYMBOL(kobject_init);
896 EXPORT_SYMBOL(kobject_register);
897 EXPORT_SYMBOL(kobject_unregister);
898 EXPORT_SYMBOL(kobject_get);
899 EXPORT_SYMBOL(kobject_put);
900 EXPORT_SYMBOL(kobject_add);
901 EXPORT_SYMBOL(kobject_del);
903 EXPORT_SYMBOL(kset_register);
904 EXPORT_SYMBOL(kset_unregister);