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 pr_debug("kobject: (%p): attempted to be registered with empty "
173 parent = kobject_get(kobj->parent);
175 /* join kset if set, use it as parent if we do not already have one */
178 parent = kobject_get(&kobj->kset->kobj);
179 kobj_kset_join(kobj);
180 kobj->parent = parent;
183 pr_debug("kobject: '%s' (%p): %s: parent: '%s', set: '%s'\n",
184 kobject_name(kobj), kobj, __func__,
185 parent ? kobject_name(parent) : "<NULL>",
186 kobj->kset ? kobject_name(&kobj->kset->kobj) : "<NULL>");
188 error = create_dir(kobj);
190 kobj_kset_leave(kobj);
194 /* be noisy on error issues */
195 if (error == -EEXIST)
196 printk(KERN_ERR "%s failed for %s with "
197 "-EEXIST, don't try to register things with "
198 "the same name in the same directory.\n",
199 __func__, kobject_name(kobj));
201 printk(KERN_ERR "%s failed for %s (%d)\n",
202 __func__, kobject_name(kobj), error);
205 kobj->state_in_sysfs = 1;
211 * kobject_set_name_vargs - Set the name of an kobject
212 * @kobj: struct kobject to set the name of
213 * @fmt: format string used to build the name
214 * @vargs: vargs to format the string.
216 static int kobject_set_name_vargs(struct kobject *kobj, const char *fmt,
219 /* Free the old name, if necessary. */
222 kobj->name = kvasprintf(GFP_KERNEL, fmt, vargs);
230 * kobject_set_name - Set the name of a kobject
231 * @kobj: struct kobject to set the name of
232 * @fmt: format string used to build the name
234 * This sets the name of the kobject. If you have already added the
235 * kobject to the system, you must call kobject_rename() in order to
236 * change the name of the kobject.
238 int kobject_set_name(struct kobject *kobj, const char *fmt, ...)
243 va_start(vargs, fmt);
244 retval = kobject_set_name_vargs(kobj, fmt, vargs);
249 EXPORT_SYMBOL(kobject_set_name);
252 * kobject_init - initialize a kobject structure
253 * @kobj: pointer to the kobject to initialize
254 * @ktype: pointer to the ktype for this kobject.
256 * This function will properly initialize a kobject such that it can then
257 * be passed to the kobject_add() call.
259 * After this function is called, the kobject MUST be cleaned up by a call
260 * to kobject_put(), not by a call to kfree directly to ensure that all of
261 * the memory is cleaned up properly.
263 void kobject_init(struct kobject *kobj, struct kobj_type *ktype)
268 err_str = "invalid kobject pointer!";
272 err_str = "must have a ktype to be initialized properly!\n";
275 if (kobj->state_initialized) {
276 /* do not error out as sometimes we can recover */
277 printk(KERN_ERR "kobject (%p): tried to init an initialized "
278 "object, something is seriously wrong.\n", kobj);
282 kobject_init_internal(kobj);
287 printk(KERN_ERR "kobject (%p): %s\n", kobj, err_str);
290 EXPORT_SYMBOL(kobject_init);
292 static int kobject_add_varg(struct kobject *kobj, struct kobject *parent,
293 const char *fmt, va_list vargs)
297 retval = kobject_set_name_vargs(kobj, fmt, vargs);
299 printk(KERN_ERR "kobject: can not set name properly!\n");
302 kobj->parent = parent;
303 return kobject_add_internal(kobj);
307 * kobject_add - the main kobject add function
308 * @kobj: the kobject to add
309 * @parent: pointer to the parent of the kobject.
310 * @fmt: format to name the kobject with.
312 * The kobject name is set and added to the kobject hierarchy in this
315 * If @parent is set, then the parent of the @kobj will be set to it.
316 * If @parent is NULL, then the parent of the @kobj will be set to the
317 * kobject associted with the kset assigned to this kobject. If no kset
318 * is assigned to the kobject, then the kobject will be located in the
319 * root of the sysfs tree.
321 * If this function returns an error, kobject_put() must be called to
322 * properly clean up the memory associated with the object.
323 * Under no instance should the kobject that is passed to this function
324 * be directly freed with a call to kfree(), that can leak memory.
326 * Note, no "add" uevent will be created with this call, the caller should set
327 * up all of the necessary sysfs files for the object and then call
328 * kobject_uevent() with the UEVENT_ADD parameter to ensure that
329 * userspace is properly notified of this kobject's creation.
331 int kobject_add(struct kobject *kobj, struct kobject *parent,
332 const char *fmt, ...)
340 if (!kobj->state_initialized) {
341 printk(KERN_ERR "kobject '%s' (%p): tried to add an "
342 "uninitialized object, something is seriously wrong.\n",
343 kobject_name(kobj), kobj);
348 retval = kobject_add_varg(kobj, parent, fmt, args);
353 EXPORT_SYMBOL(kobject_add);
356 * kobject_init_and_add - initialize a kobject structure and add it to the kobject hierarchy
357 * @kobj: pointer to the kobject to initialize
358 * @ktype: pointer to the ktype for this kobject.
359 * @parent: pointer to the parent of this kobject.
360 * @fmt: the name of the kobject.
362 * This function combines the call to kobject_init() and
363 * kobject_add(). The same type of error handling after a call to
364 * kobject_add() and kobject lifetime rules are the same here.
366 int kobject_init_and_add(struct kobject *kobj, struct kobj_type *ktype,
367 struct kobject *parent, const char *fmt, ...)
372 kobject_init(kobj, ktype);
375 retval = kobject_add_varg(kobj, parent, fmt, args);
380 EXPORT_SYMBOL_GPL(kobject_init_and_add);
383 * kobject_rename - change the name of an object
384 * @kobj: object in question.
385 * @new_name: object's new name
387 int kobject_rename(struct kobject *kobj, const char *new_name)
390 const char *devpath = NULL;
391 char *devpath_string = NULL;
394 kobj = kobject_get(kobj);
400 /* see if this name is already in use */
402 struct kobject *temp_kobj;
403 temp_kobj = kset_find_obj(kobj->kset, new_name);
405 printk(KERN_WARNING "kobject '%s' cannot be renamed "
406 "to '%s' as '%s' is already in existence.\n",
407 kobject_name(kobj), new_name, new_name);
408 kobject_put(temp_kobj);
413 devpath = kobject_get_path(kobj, GFP_KERNEL);
418 devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
419 if (!devpath_string) {
423 sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
424 envp[0] = devpath_string;
427 error = sysfs_rename_dir(kobj, new_name);
429 /* This function is mostly/only used for network interface.
430 * Some hotplug package track interfaces by their name and
431 * therefore want to know when the name is changed by the user. */
433 kobject_uevent_env(kobj, KOBJ_MOVE, envp);
436 kfree(devpath_string);
442 EXPORT_SYMBOL_GPL(kobject_rename);
445 * kobject_move - move object to another parent
446 * @kobj: object in question.
447 * @new_parent: object's new parent (can be NULL)
449 int kobject_move(struct kobject *kobj, struct kobject *new_parent)
452 struct kobject *old_parent;
453 const char *devpath = NULL;
454 char *devpath_string = NULL;
457 kobj = kobject_get(kobj);
460 new_parent = kobject_get(new_parent);
463 new_parent = kobject_get(&kobj->kset->kobj);
465 /* old object path */
466 devpath = kobject_get_path(kobj, GFP_KERNEL);
471 devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
472 if (!devpath_string) {
476 sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
477 envp[0] = devpath_string;
479 error = sysfs_move_dir(kobj, new_parent);
482 old_parent = kobj->parent;
483 kobj->parent = new_parent;
485 kobject_put(old_parent);
486 kobject_uevent_env(kobj, KOBJ_MOVE, envp);
488 kobject_put(new_parent);
490 kfree(devpath_string);
496 * kobject_del - unlink kobject from hierarchy.
499 void kobject_del(struct kobject *kobj)
504 sysfs_remove_dir(kobj);
505 kobj->state_in_sysfs = 0;
506 kobj_kset_leave(kobj);
507 kobject_put(kobj->parent);
512 * kobject_get - increment refcount for object.
515 struct kobject *kobject_get(struct kobject *kobj)
518 kref_get(&kobj->kref);
523 * kobject_cleanup - free kobject resources.
524 * @kobj: object to cleanup
526 static void kobject_cleanup(struct kobject *kobj)
528 struct kobj_type *t = get_ktype(kobj);
529 const char *name = kobj->name;
531 pr_debug("kobject: '%s' (%p): %s\n",
532 kobject_name(kobj), kobj, __func__);
534 if (t && !t->release)
535 pr_debug("kobject: '%s' (%p): does not have a release() "
536 "function, it is broken and must be fixed.\n",
537 kobject_name(kobj), kobj);
539 /* send "remove" if the caller did not do it but sent "add" */
540 if (kobj->state_add_uevent_sent && !kobj->state_remove_uevent_sent) {
541 pr_debug("kobject: '%s' (%p): auto cleanup 'remove' event\n",
542 kobject_name(kobj), kobj);
543 kobject_uevent(kobj, KOBJ_REMOVE);
546 /* remove from sysfs if the caller did not do it */
547 if (kobj->state_in_sysfs) {
548 pr_debug("kobject: '%s' (%p): auto cleanup kobject_del\n",
549 kobject_name(kobj), kobj);
553 if (t && t->release) {
554 pr_debug("kobject: '%s' (%p): calling ktype release\n",
555 kobject_name(kobj), kobj);
559 /* free name if we allocated it */
561 pr_debug("kobject: '%s': free name\n", name);
566 static void kobject_release(struct kref *kref)
568 kobject_cleanup(container_of(kref, struct kobject, kref));
572 * kobject_put - decrement refcount for object.
575 * Decrement the refcount, and if 0, call kobject_cleanup().
577 void kobject_put(struct kobject *kobj)
580 if (!kobj->state_initialized) {
581 printk(KERN_WARNING "kobject: '%s' (%p): is not "
582 "initialized, yet kobject_put() is being "
583 "called.\n", kobject_name(kobj), kobj);
586 kref_put(&kobj->kref, kobject_release);
590 static void dynamic_kobj_release(struct kobject *kobj)
592 pr_debug("kobject: (%p): %s\n", kobj, __func__);
596 static struct kobj_type dynamic_kobj_ktype = {
597 .release = dynamic_kobj_release,
598 .sysfs_ops = &kobj_sysfs_ops,
602 * kobject_create - create a struct kobject dynamically
604 * This function creates a kobject structure dynamically and sets it up
605 * to be a "dynamic" kobject with a default release function set up.
607 * If the kobject was not able to be created, NULL will be returned.
608 * The kobject structure returned from here must be cleaned up with a
609 * call to kobject_put() and not kfree(), as kobject_init() has
610 * already been called on this structure.
612 struct kobject *kobject_create(void)
614 struct kobject *kobj;
616 kobj = kzalloc(sizeof(*kobj), GFP_KERNEL);
620 kobject_init(kobj, &dynamic_kobj_ktype);
625 * kobject_create_and_add - create a struct kobject dynamically and register it with sysfs
627 * @name: the name for the kset
628 * @parent: the parent kobject of this kobject, if any.
630 * This function creates a kobject structure dynamically and registers it
631 * with sysfs. When you are finished with this structure, call
632 * kobject_put() and the structure will be dynamically freed when
633 * it is no longer being used.
635 * If the kobject was not able to be created, NULL will be returned.
637 struct kobject *kobject_create_and_add(const char *name, struct kobject *parent)
639 struct kobject *kobj;
642 kobj = kobject_create();
646 retval = kobject_add(kobj, parent, "%s", name);
648 printk(KERN_WARNING "%s: kobject_add error: %d\n",
655 EXPORT_SYMBOL_GPL(kobject_create_and_add);
658 * kset_init - initialize a kset for use
661 void kset_init(struct kset *k)
663 kobject_init_internal(&k->kobj);
664 INIT_LIST_HEAD(&k->list);
665 spin_lock_init(&k->list_lock);
668 /* default kobject attribute operations */
669 static ssize_t kobj_attr_show(struct kobject *kobj, struct attribute *attr,
672 struct kobj_attribute *kattr;
675 kattr = container_of(attr, struct kobj_attribute, attr);
677 ret = kattr->show(kobj, kattr, buf);
681 static ssize_t kobj_attr_store(struct kobject *kobj, struct attribute *attr,
682 const char *buf, size_t count)
684 struct kobj_attribute *kattr;
687 kattr = container_of(attr, struct kobj_attribute, attr);
689 ret = kattr->store(kobj, kattr, buf, count);
693 struct sysfs_ops kobj_sysfs_ops = {
694 .show = kobj_attr_show,
695 .store = kobj_attr_store,
699 * kset_register - initialize and add a kset.
702 int kset_register(struct kset *k)
710 err = kobject_add_internal(&k->kobj);
713 kobject_uevent(&k->kobj, KOBJ_ADD);
718 * kset_unregister - remove a kset.
721 void kset_unregister(struct kset *k)
725 kobject_put(&k->kobj);
729 * kset_find_obj - search for object in kset.
730 * @kset: kset we're looking in.
731 * @name: object's name.
733 * Lock kset via @kset->subsys, and iterate over @kset->list,
734 * looking for a matching kobject. If matching object is found
735 * take a reference and return the object.
737 struct kobject *kset_find_obj(struct kset *kset, const char *name)
740 struct kobject *ret = NULL;
742 spin_lock(&kset->list_lock);
743 list_for_each_entry(k, &kset->list, entry) {
744 if (kobject_name(k) && !strcmp(kobject_name(k), name)) {
745 ret = kobject_get(k);
749 spin_unlock(&kset->list_lock);
753 static void kset_release(struct kobject *kobj)
755 struct kset *kset = container_of(kobj, struct kset, kobj);
756 pr_debug("kobject: '%s' (%p): %s\n",
757 kobject_name(kobj), kobj, __func__);
761 static struct kobj_type kset_ktype = {
762 .sysfs_ops = &kobj_sysfs_ops,
763 .release = kset_release,
767 * kset_create - create a struct kset dynamically
769 * @name: the name for the kset
770 * @uevent_ops: a struct kset_uevent_ops for the kset
771 * @parent_kobj: the parent kobject of this kset, if any.
773 * This function creates a kset structure dynamically. This structure can
774 * then be registered with the system and show up in sysfs with a call to
775 * kset_register(). When you are finished with this structure, if
776 * kset_register() has been called, call kset_unregister() and the
777 * structure will be dynamically freed when it is no longer being used.
779 * If the kset was not able to be created, NULL will be returned.
781 static struct kset *kset_create(const char *name,
782 struct kset_uevent_ops *uevent_ops,
783 struct kobject *parent_kobj)
787 kset = kzalloc(sizeof(*kset), GFP_KERNEL);
790 kobject_set_name(&kset->kobj, name);
791 kset->uevent_ops = uevent_ops;
792 kset->kobj.parent = parent_kobj;
795 * The kobject of this kset will have a type of kset_ktype and belong to
796 * no kset itself. That way we can properly free it when it is
797 * finished being used.
799 kset->kobj.ktype = &kset_ktype;
800 kset->kobj.kset = NULL;
806 * kset_create_and_add - create a struct kset dynamically and add it to sysfs
808 * @name: the name for the kset
809 * @uevent_ops: a struct kset_uevent_ops for the kset
810 * @parent_kobj: the parent kobject of this kset, if any.
812 * This function creates a kset structure dynamically and registers it
813 * with sysfs. When you are finished with this structure, call
814 * kset_unregister() and the structure will be dynamically freed when it
815 * is no longer being used.
817 * If the kset was not able to be created, NULL will be returned.
819 struct kset *kset_create_and_add(const char *name,
820 struct kset_uevent_ops *uevent_ops,
821 struct kobject *parent_kobj)
826 kset = kset_create(name, uevent_ops, parent_kobj);
829 error = kset_register(kset);
836 EXPORT_SYMBOL_GPL(kset_create_and_add);
838 EXPORT_SYMBOL(kobject_get);
839 EXPORT_SYMBOL(kobject_put);
840 EXPORT_SYMBOL(kobject_del);
842 EXPORT_SYMBOL(kset_register);
843 EXPORT_SYMBOL(kset_unregister);