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 are associated
26 * with an object that registers with them. This is a helper called during
27 * object registration that loops through the default attributes of the
28 * subsystem and creates attributes files for them in sysfs.
30 static int populate_dir(struct kobject *kobj)
32 struct kobj_type *t = get_ktype(kobj);
33 struct attribute *attr;
37 if (t && t->default_attrs) {
38 for (i = 0; (attr = t->default_attrs[i]) != NULL; i++) {
39 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 error = populate_dir(kobj);
55 sysfs_remove_dir(kobj);
61 static int get_kobj_path_length(struct kobject *kobj)
64 struct kobject *parent = kobj;
66 /* walk up the ancestors until we hit the one pointing to the
68 * Add 1 to strlen for leading '/' of each level.
71 if (kobject_name(parent) == NULL)
73 length += strlen(kobject_name(parent)) + 1;
74 parent = parent->parent;
79 static void fill_kobj_path(struct kobject *kobj, char *path, int length)
81 struct kobject *parent;
84 for (parent = kobj; parent; parent = parent->parent) {
85 int cur = strlen(kobject_name(parent));
86 /* back up enough to print this name with '/' */
88 strncpy(path + length, kobject_name(parent), cur);
89 *(path + --length) = '/';
92 pr_debug("kobject: '%s' (%p): %s: path = '%s'\n", kobject_name(kobj),
93 kobj, __func__, path);
97 * kobject_get_path - generate and return the path associated with a given kobj and kset pair.
99 * @kobj: kobject in question, with which to build the path
100 * @gfp_mask: the allocation type used to allocate the path
102 * The result must be freed by the caller with kfree().
104 char *kobject_get_path(struct kobject *kobj, gfp_t gfp_mask)
109 len = get_kobj_path_length(kobj);
112 path = kzalloc(len, gfp_mask);
115 fill_kobj_path(kobj, path, len);
119 EXPORT_SYMBOL_GPL(kobject_get_path);
121 /* add the kobject to its kset's list */
122 static void kobj_kset_join(struct kobject *kobj)
127 kset_get(kobj->kset);
128 spin_lock(&kobj->kset->list_lock);
129 list_add_tail(&kobj->entry, &kobj->kset->list);
130 spin_unlock(&kobj->kset->list_lock);
133 /* remove the kobject from its kset's list */
134 static void kobj_kset_leave(struct kobject *kobj)
139 spin_lock(&kobj->kset->list_lock);
140 list_del_init(&kobj->entry);
141 spin_unlock(&kobj->kset->list_lock);
142 kset_put(kobj->kset);
145 static void kobject_init_internal(struct kobject *kobj)
149 kref_init(&kobj->kref);
150 INIT_LIST_HEAD(&kobj->entry);
151 kobj->state_in_sysfs = 0;
152 kobj->state_add_uevent_sent = 0;
153 kobj->state_remove_uevent_sent = 0;
154 kobj->state_initialized = 1;
158 static int kobject_add_internal(struct kobject *kobj)
161 struct kobject *parent;
166 if (!kobj->name || !kobj->name[0]) {
167 WARN(1, "kobject: (%p): attempted to be registered with empty "
172 parent = kobject_get(kobj->parent);
174 /* join kset if set, use it as parent if we do not already have one */
177 parent = kobject_get(&kobj->kset->kobj);
178 kobj_kset_join(kobj);
179 kobj->parent = parent;
182 pr_debug("kobject: '%s' (%p): %s: parent: '%s', set: '%s'\n",
183 kobject_name(kobj), kobj, __func__,
184 parent ? kobject_name(parent) : "<NULL>",
185 kobj->kset ? kobject_name(&kobj->kset->kobj) : "<NULL>");
187 error = create_dir(kobj);
189 kobj_kset_leave(kobj);
193 /* be noisy on error issues */
194 if (error == -EEXIST)
195 printk(KERN_ERR "%s failed for %s with "
196 "-EEXIST, don't try to register things with "
197 "the same name in the same directory.\n",
198 __func__, kobject_name(kobj));
200 printk(KERN_ERR "%s failed for %s (%d)\n",
201 __func__, kobject_name(kobj), error);
204 kobj->state_in_sysfs = 1;
210 * kobject_set_name_vargs - Set the name of an kobject
211 * @kobj: struct kobject to set the name of
212 * @fmt: format string used to build the name
213 * @vargs: vargs to format the string.
215 static int kobject_set_name_vargs(struct kobject *kobj, const char *fmt,
218 const char *old_name = kobj->name;
221 kobj->name = kvasprintf(GFP_KERNEL, fmt, vargs);
225 /* ewww... some of these buggers have '/' in the name ... */
226 while ((s = strchr(kobj->name, '/')))
234 * kobject_set_name - Set the name of a kobject
235 * @kobj: struct kobject to set the name of
236 * @fmt: format string used to build the name
238 * This sets the name of the kobject. If you have already added the
239 * kobject to the system, you must call kobject_rename() in order to
240 * change the name of the kobject.
242 int kobject_set_name(struct kobject *kobj, const char *fmt, ...)
247 va_start(vargs, fmt);
248 retval = kobject_set_name_vargs(kobj, fmt, vargs);
253 EXPORT_SYMBOL(kobject_set_name);
256 * kobject_init - initialize a kobject structure
257 * @kobj: pointer to the kobject to initialize
258 * @ktype: pointer to the ktype for this kobject.
260 * This function will properly initialize a kobject such that it can then
261 * be passed to the kobject_add() call.
263 * After this function is called, the kobject MUST be cleaned up by a call
264 * to kobject_put(), not by a call to kfree directly to ensure that all of
265 * the memory is cleaned up properly.
267 void kobject_init(struct kobject *kobj, struct kobj_type *ktype)
272 err_str = "invalid kobject pointer!";
276 err_str = "must have a ktype to be initialized properly!\n";
279 if (kobj->state_initialized) {
280 /* do not error out as sometimes we can recover */
281 printk(KERN_ERR "kobject (%p): tried to init an initialized "
282 "object, something is seriously wrong.\n", kobj);
286 kobject_init_internal(kobj);
291 printk(KERN_ERR "kobject (%p): %s\n", kobj, err_str);
294 EXPORT_SYMBOL(kobject_init);
296 static int kobject_add_varg(struct kobject *kobj, struct kobject *parent,
297 const char *fmt, va_list vargs)
301 retval = kobject_set_name_vargs(kobj, fmt, vargs);
303 printk(KERN_ERR "kobject: can not set name properly!\n");
306 kobj->parent = parent;
307 return kobject_add_internal(kobj);
311 * kobject_add - the main kobject add function
312 * @kobj: the kobject to add
313 * @parent: pointer to the parent of the kobject.
314 * @fmt: format to name the kobject with.
316 * The kobject name is set and added to the kobject hierarchy in this
319 * If @parent is set, then the parent of the @kobj will be set to it.
320 * If @parent is NULL, then the parent of the @kobj will be set to the
321 * kobject associted with the kset assigned to this kobject. If no kset
322 * is assigned to the kobject, then the kobject will be located in the
323 * root of the sysfs tree.
325 * If this function returns an error, kobject_put() must be called to
326 * properly clean up the memory associated with the object.
327 * Under no instance should the kobject that is passed to this function
328 * be directly freed with a call to kfree(), that can leak memory.
330 * Note, no "add" uevent will be created with this call, the caller should set
331 * up all of the necessary sysfs files for the object and then call
332 * kobject_uevent() with the UEVENT_ADD parameter to ensure that
333 * userspace is properly notified of this kobject's creation.
335 int kobject_add(struct kobject *kobj, struct kobject *parent,
336 const char *fmt, ...)
344 if (!kobj->state_initialized) {
345 printk(KERN_ERR "kobject '%s' (%p): tried to add an "
346 "uninitialized object, something is seriously wrong.\n",
347 kobject_name(kobj), kobj);
352 retval = kobject_add_varg(kobj, parent, fmt, args);
357 EXPORT_SYMBOL(kobject_add);
360 * kobject_init_and_add - initialize a kobject structure and add it to the kobject hierarchy
361 * @kobj: pointer to the kobject to initialize
362 * @ktype: pointer to the ktype for this kobject.
363 * @parent: pointer to the parent of this kobject.
364 * @fmt: the name of the kobject.
366 * This function combines the call to kobject_init() and
367 * kobject_add(). The same type of error handling after a call to
368 * kobject_add() and kobject lifetime rules are the same here.
370 int kobject_init_and_add(struct kobject *kobj, struct kobj_type *ktype,
371 struct kobject *parent, const char *fmt, ...)
376 kobject_init(kobj, ktype);
379 retval = kobject_add_varg(kobj, parent, fmt, args);
384 EXPORT_SYMBOL_GPL(kobject_init_and_add);
387 * kobject_rename - change the name of an object
388 * @kobj: object in question.
389 * @new_name: object's new name
391 * It is the responsibility of the caller to provide mutual
392 * exclusion between two different calls of kobject_rename
393 * on the same kobject and to ensure that new_name is valid and
394 * won't conflict with other kobjects.
396 int kobject_rename(struct kobject *kobj, const char *new_name)
399 const char *devpath = NULL;
400 char *devpath_string = NULL;
403 kobj = kobject_get(kobj);
409 devpath = kobject_get_path(kobj, GFP_KERNEL);
414 devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
415 if (!devpath_string) {
419 sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
420 envp[0] = devpath_string;
423 error = sysfs_rename_dir(kobj, new_name);
425 /* This function is mostly/only used for network interface.
426 * Some hotplug package track interfaces by their name and
427 * therefore want to know when the name is changed by the user. */
429 kobject_uevent_env(kobj, KOBJ_MOVE, envp);
432 kfree(devpath_string);
438 EXPORT_SYMBOL_GPL(kobject_rename);
441 * kobject_move - move object to another parent
442 * @kobj: object in question.
443 * @new_parent: object's new parent (can be NULL)
445 int kobject_move(struct kobject *kobj, struct kobject *new_parent)
448 struct kobject *old_parent;
449 const char *devpath = NULL;
450 char *devpath_string = NULL;
453 kobj = kobject_get(kobj);
456 new_parent = kobject_get(new_parent);
459 new_parent = kobject_get(&kobj->kset->kobj);
461 /* old object path */
462 devpath = kobject_get_path(kobj, GFP_KERNEL);
467 devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
468 if (!devpath_string) {
472 sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
473 envp[0] = devpath_string;
475 error = sysfs_move_dir(kobj, new_parent);
478 old_parent = kobj->parent;
479 kobj->parent = new_parent;
481 kobject_put(old_parent);
482 kobject_uevent_env(kobj, KOBJ_MOVE, envp);
484 kobject_put(new_parent);
486 kfree(devpath_string);
492 * kobject_del - unlink kobject from hierarchy.
495 void kobject_del(struct kobject *kobj)
500 sysfs_remove_dir(kobj);
501 kobj->state_in_sysfs = 0;
502 kobj_kset_leave(kobj);
503 kobject_put(kobj->parent);
508 * kobject_get - increment refcount for object.
511 struct kobject *kobject_get(struct kobject *kobj)
514 kref_get(&kobj->kref);
519 * kobject_cleanup - free kobject resources.
520 * @kobj: object to cleanup
522 static void kobject_cleanup(struct kobject *kobj)
524 struct kobj_type *t = get_ktype(kobj);
525 const char *name = kobj->name;
527 pr_debug("kobject: '%s' (%p): %s\n",
528 kobject_name(kobj), kobj, __func__);
530 if (t && !t->release)
531 pr_debug("kobject: '%s' (%p): does not have a release() "
532 "function, it is broken and must be fixed.\n",
533 kobject_name(kobj), kobj);
535 /* send "remove" if the caller did not do it but sent "add" */
536 if (kobj->state_add_uevent_sent && !kobj->state_remove_uevent_sent) {
537 pr_debug("kobject: '%s' (%p): auto cleanup 'remove' event\n",
538 kobject_name(kobj), kobj);
539 kobject_uevent(kobj, KOBJ_REMOVE);
542 /* remove from sysfs if the caller did not do it */
543 if (kobj->state_in_sysfs) {
544 pr_debug("kobject: '%s' (%p): auto cleanup kobject_del\n",
545 kobject_name(kobj), kobj);
549 if (t && t->release) {
550 pr_debug("kobject: '%s' (%p): calling ktype release\n",
551 kobject_name(kobj), kobj);
555 /* free name if we allocated it */
557 pr_debug("kobject: '%s': free name\n", name);
562 static void kobject_release(struct kref *kref)
564 kobject_cleanup(container_of(kref, struct kobject, kref));
568 * kobject_put - decrement refcount for object.
571 * Decrement the refcount, and if 0, call kobject_cleanup().
573 void kobject_put(struct kobject *kobj)
576 if (!kobj->state_initialized)
577 WARN(1, KERN_WARNING "kobject: '%s' (%p): is not "
578 "initialized, yet kobject_put() is being "
579 "called.\n", kobject_name(kobj), kobj);
580 kref_put(&kobj->kref, kobject_release);
584 static void dynamic_kobj_release(struct kobject *kobj)
586 pr_debug("kobject: (%p): %s\n", kobj, __func__);
590 static struct kobj_type dynamic_kobj_ktype = {
591 .release = dynamic_kobj_release,
592 .sysfs_ops = &kobj_sysfs_ops,
596 * kobject_create - create a struct kobject dynamically
598 * This function creates a kobject structure dynamically and sets it up
599 * to be a "dynamic" kobject with a default release function set up.
601 * If the kobject was not able to be created, NULL will be returned.
602 * The kobject structure returned from here must be cleaned up with a
603 * call to kobject_put() and not kfree(), as kobject_init() has
604 * already been called on this structure.
606 struct kobject *kobject_create(void)
608 struct kobject *kobj;
610 kobj = kzalloc(sizeof(*kobj), GFP_KERNEL);
614 kobject_init(kobj, &dynamic_kobj_ktype);
619 * kobject_create_and_add - create a struct kobject dynamically and register it with sysfs
621 * @name: the name for the kset
622 * @parent: the parent kobject of this kobject, if any.
624 * This function creates a kobject structure dynamically and registers it
625 * with sysfs. When you are finished with this structure, call
626 * kobject_put() and the structure will be dynamically freed when
627 * it is no longer being used.
629 * If the kobject was not able to be created, NULL will be returned.
631 struct kobject *kobject_create_and_add(const char *name, struct kobject *parent)
633 struct kobject *kobj;
636 kobj = kobject_create();
640 retval = kobject_add(kobj, parent, "%s", name);
642 printk(KERN_WARNING "%s: kobject_add error: %d\n",
649 EXPORT_SYMBOL_GPL(kobject_create_and_add);
652 * kset_init - initialize a kset for use
655 void kset_init(struct kset *k)
657 kobject_init_internal(&k->kobj);
658 INIT_LIST_HEAD(&k->list);
659 spin_lock_init(&k->list_lock);
662 /* default kobject attribute operations */
663 static ssize_t kobj_attr_show(struct kobject *kobj, struct attribute *attr,
666 struct kobj_attribute *kattr;
669 kattr = container_of(attr, struct kobj_attribute, attr);
671 ret = kattr->show(kobj, kattr, buf);
675 static ssize_t kobj_attr_store(struct kobject *kobj, struct attribute *attr,
676 const char *buf, size_t count)
678 struct kobj_attribute *kattr;
681 kattr = container_of(attr, struct kobj_attribute, attr);
683 ret = kattr->store(kobj, kattr, buf, count);
687 struct sysfs_ops kobj_sysfs_ops = {
688 .show = kobj_attr_show,
689 .store = kobj_attr_store,
693 * kset_register - initialize and add a kset.
696 int kset_register(struct kset *k)
704 err = kobject_add_internal(&k->kobj);
707 kobject_uevent(&k->kobj, KOBJ_ADD);
712 * kset_unregister - remove a kset.
715 void kset_unregister(struct kset *k)
719 kobject_put(&k->kobj);
723 * kset_find_obj - search for object in kset.
724 * @kset: kset we're looking in.
725 * @name: object's name.
727 * Lock kset via @kset->subsys, and iterate over @kset->list,
728 * looking for a matching kobject. If matching object is found
729 * take a reference and return the object.
731 struct kobject *kset_find_obj(struct kset *kset, const char *name)
734 struct kobject *ret = NULL;
736 spin_lock(&kset->list_lock);
737 list_for_each_entry(k, &kset->list, entry) {
738 if (kobject_name(k) && !strcmp(kobject_name(k), name)) {
739 ret = kobject_get(k);
743 spin_unlock(&kset->list_lock);
747 static void kset_release(struct kobject *kobj)
749 struct kset *kset = container_of(kobj, struct kset, kobj);
750 pr_debug("kobject: '%s' (%p): %s\n",
751 kobject_name(kobj), kobj, __func__);
755 static struct kobj_type kset_ktype = {
756 .sysfs_ops = &kobj_sysfs_ops,
757 .release = kset_release,
761 * kset_create - create a struct kset dynamically
763 * @name: the name for the kset
764 * @uevent_ops: a struct kset_uevent_ops for the kset
765 * @parent_kobj: the parent kobject of this kset, if any.
767 * This function creates a kset structure dynamically. This structure can
768 * then be registered with the system and show up in sysfs with a call to
769 * kset_register(). When you are finished with this structure, if
770 * kset_register() has been called, call kset_unregister() and the
771 * structure will be dynamically freed when it is no longer being used.
773 * If the kset was not able to be created, NULL will be returned.
775 static struct kset *kset_create(const char *name,
776 struct kset_uevent_ops *uevent_ops,
777 struct kobject *parent_kobj)
781 kset = kzalloc(sizeof(*kset), GFP_KERNEL);
784 kobject_set_name(&kset->kobj, name);
785 kset->uevent_ops = uevent_ops;
786 kset->kobj.parent = parent_kobj;
789 * The kobject of this kset will have a type of kset_ktype and belong to
790 * no kset itself. That way we can properly free it when it is
791 * finished being used.
793 kset->kobj.ktype = &kset_ktype;
794 kset->kobj.kset = NULL;
800 * kset_create_and_add - create a struct kset dynamically and add it to sysfs
802 * @name: the name for the kset
803 * @uevent_ops: a struct kset_uevent_ops for the kset
804 * @parent_kobj: the parent kobject of this kset, if any.
806 * This function creates a kset structure dynamically and registers it
807 * with sysfs. When you are finished with this structure, call
808 * kset_unregister() and the structure will be dynamically freed when it
809 * is no longer being used.
811 * If the kset was not able to be created, NULL will be returned.
813 struct kset *kset_create_and_add(const char *name,
814 struct kset_uevent_ops *uevent_ops,
815 struct kobject *parent_kobj)
820 kset = kset_create(name, uevent_ops, parent_kobj);
823 error = kset_register(kset);
830 EXPORT_SYMBOL_GPL(kset_create_and_add);
832 EXPORT_SYMBOL(kobject_get);
833 EXPORT_SYMBOL(kobject_put);
834 EXPORT_SYMBOL(kobject_del);
836 EXPORT_SYMBOL(kset_register);
837 EXPORT_SYMBOL(kset_unregister);