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 int kobject_set_name_vargs(struct kobject *kobj, const char *fmt,
218 const char *old_name = kobj->name;
221 if (kobj->name && !fmt)
224 kobj->name = kvasprintf(GFP_KERNEL, fmt, vargs);
228 /* ewww... some of these buggers have '/' in the name ... */
229 while ((s = strchr(kobj->name, '/')))
237 * kobject_set_name - Set the name of a kobject
238 * @kobj: struct kobject to set the name of
239 * @fmt: format string used to build the name
241 * This sets the name of the kobject. If you have already added the
242 * kobject to the system, you must call kobject_rename() in order to
243 * change the name of the kobject.
245 int kobject_set_name(struct kobject *kobj, const char *fmt, ...)
250 va_start(vargs, fmt);
251 retval = kobject_set_name_vargs(kobj, fmt, vargs);
256 EXPORT_SYMBOL(kobject_set_name);
259 * kobject_init - initialize a kobject structure
260 * @kobj: pointer to the kobject to initialize
261 * @ktype: pointer to the ktype for this kobject.
263 * This function will properly initialize a kobject such that it can then
264 * be passed to the kobject_add() call.
266 * After this function is called, the kobject MUST be cleaned up by a call
267 * to kobject_put(), not by a call to kfree directly to ensure that all of
268 * the memory is cleaned up properly.
270 void kobject_init(struct kobject *kobj, struct kobj_type *ktype)
275 err_str = "invalid kobject pointer!";
279 err_str = "must have a ktype to be initialized properly!\n";
282 if (kobj->state_initialized) {
283 /* do not error out as sometimes we can recover */
284 printk(KERN_ERR "kobject (%p): tried to init an initialized "
285 "object, something is seriously wrong.\n", kobj);
289 kobject_init_internal(kobj);
294 printk(KERN_ERR "kobject (%p): %s\n", kobj, err_str);
297 EXPORT_SYMBOL(kobject_init);
299 static int kobject_add_varg(struct kobject *kobj, struct kobject *parent,
300 const char *fmt, va_list vargs)
304 retval = kobject_set_name_vargs(kobj, fmt, vargs);
306 printk(KERN_ERR "kobject: can not set name properly!\n");
309 kobj->parent = parent;
310 return kobject_add_internal(kobj);
314 * kobject_add - the main kobject add function
315 * @kobj: the kobject to add
316 * @parent: pointer to the parent of the kobject.
317 * @fmt: format to name the kobject with.
319 * The kobject name is set and added to the kobject hierarchy in this
322 * If @parent is set, then the parent of the @kobj will be set to it.
323 * If @parent is NULL, then the parent of the @kobj will be set to the
324 * kobject associted with the kset assigned to this kobject. If no kset
325 * is assigned to the kobject, then the kobject will be located in the
326 * root of the sysfs tree.
328 * If this function returns an error, kobject_put() must be called to
329 * properly clean up the memory associated with the object.
330 * Under no instance should the kobject that is passed to this function
331 * be directly freed with a call to kfree(), that can leak memory.
333 * Note, no "add" uevent will be created with this call, the caller should set
334 * up all of the necessary sysfs files for the object and then call
335 * kobject_uevent() with the UEVENT_ADD parameter to ensure that
336 * userspace is properly notified of this kobject's creation.
338 int kobject_add(struct kobject *kobj, struct kobject *parent,
339 const char *fmt, ...)
347 if (!kobj->state_initialized) {
348 printk(KERN_ERR "kobject '%s' (%p): tried to add an "
349 "uninitialized object, something is seriously wrong.\n",
350 kobject_name(kobj), kobj);
355 retval = kobject_add_varg(kobj, parent, fmt, args);
360 EXPORT_SYMBOL(kobject_add);
363 * kobject_init_and_add - initialize a kobject structure and add it to the kobject hierarchy
364 * @kobj: pointer to the kobject to initialize
365 * @ktype: pointer to the ktype for this kobject.
366 * @parent: pointer to the parent of this kobject.
367 * @fmt: the name of the kobject.
369 * This function combines the call to kobject_init() and
370 * kobject_add(). The same type of error handling after a call to
371 * kobject_add() and kobject lifetime rules are the same here.
373 int kobject_init_and_add(struct kobject *kobj, struct kobj_type *ktype,
374 struct kobject *parent, const char *fmt, ...)
379 kobject_init(kobj, ktype);
382 retval = kobject_add_varg(kobj, parent, fmt, args);
387 EXPORT_SYMBOL_GPL(kobject_init_and_add);
390 * kobject_rename - change the name of an object
391 * @kobj: object in question.
392 * @new_name: object's new name
394 * It is the responsibility of the caller to provide mutual
395 * exclusion between two different calls of kobject_rename
396 * on the same kobject and to ensure that new_name is valid and
397 * won't conflict with other kobjects.
399 int kobject_rename(struct kobject *kobj, const char *new_name)
402 const char *devpath = NULL;
403 const char *dup_name = NULL, *name;
404 char *devpath_string = NULL;
407 kobj = kobject_get(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 name = dup_name = kstrdup(new_name, GFP_KERNEL);
433 error = sysfs_rename_dir(kobj, new_name);
437 /* Install the new kobject name */
438 dup_name = kobj->name;
441 /* This function is mostly/only used for network interface.
442 * Some hotplug package track interfaces by their name and
443 * therefore want to know when the name is changed by the user. */
444 kobject_uevent_env(kobj, KOBJ_MOVE, envp);
448 kfree(devpath_string);
454 EXPORT_SYMBOL_GPL(kobject_rename);
457 * kobject_move - move object to another parent
458 * @kobj: object in question.
459 * @new_parent: object's new parent (can be NULL)
461 int kobject_move(struct kobject *kobj, struct kobject *new_parent)
464 struct kobject *old_parent;
465 const char *devpath = NULL;
466 char *devpath_string = NULL;
469 kobj = kobject_get(kobj);
472 new_parent = kobject_get(new_parent);
475 new_parent = kobject_get(&kobj->kset->kobj);
477 /* old object path */
478 devpath = kobject_get_path(kobj, GFP_KERNEL);
483 devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
484 if (!devpath_string) {
488 sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
489 envp[0] = devpath_string;
491 error = sysfs_move_dir(kobj, new_parent);
494 old_parent = kobj->parent;
495 kobj->parent = new_parent;
497 kobject_put(old_parent);
498 kobject_uevent_env(kobj, KOBJ_MOVE, envp);
500 kobject_put(new_parent);
502 kfree(devpath_string);
508 * kobject_del - unlink kobject from hierarchy.
511 void kobject_del(struct kobject *kobj)
516 sysfs_remove_dir(kobj);
517 kobj->state_in_sysfs = 0;
518 kobj_kset_leave(kobj);
519 kobject_put(kobj->parent);
524 * kobject_get - increment refcount for object.
527 struct kobject *kobject_get(struct kobject *kobj)
530 kref_get(&kobj->kref);
535 * kobject_cleanup - free kobject resources.
536 * @kobj: object to cleanup
538 static void kobject_cleanup(struct kobject *kobj)
540 struct kobj_type *t = get_ktype(kobj);
541 const char *name = kobj->name;
543 pr_debug("kobject: '%s' (%p): %s\n",
544 kobject_name(kobj), kobj, __func__);
546 if (t && !t->release)
547 pr_debug("kobject: '%s' (%p): does not have a release() "
548 "function, it is broken and must be fixed.\n",
549 kobject_name(kobj), kobj);
551 /* send "remove" if the caller did not do it but sent "add" */
552 if (kobj->state_add_uevent_sent && !kobj->state_remove_uevent_sent) {
553 pr_debug("kobject: '%s' (%p): auto cleanup 'remove' event\n",
554 kobject_name(kobj), kobj);
555 kobject_uevent(kobj, KOBJ_REMOVE);
558 /* remove from sysfs if the caller did not do it */
559 if (kobj->state_in_sysfs) {
560 pr_debug("kobject: '%s' (%p): auto cleanup kobject_del\n",
561 kobject_name(kobj), kobj);
565 if (t && t->release) {
566 pr_debug("kobject: '%s' (%p): calling ktype release\n",
567 kobject_name(kobj), kobj);
571 /* free name if we allocated it */
573 pr_debug("kobject: '%s': free name\n", name);
578 static void kobject_release(struct kref *kref)
580 kobject_cleanup(container_of(kref, struct kobject, kref));
584 * kobject_put - decrement refcount for object.
587 * Decrement the refcount, and if 0, call kobject_cleanup().
589 void kobject_put(struct kobject *kobj)
592 if (!kobj->state_initialized)
593 WARN(1, KERN_WARNING "kobject: '%s' (%p): is not "
594 "initialized, yet kobject_put() is being "
595 "called.\n", kobject_name(kobj), kobj);
596 kref_put(&kobj->kref, kobject_release);
600 static void dynamic_kobj_release(struct kobject *kobj)
602 pr_debug("kobject: (%p): %s\n", kobj, __func__);
606 static struct kobj_type dynamic_kobj_ktype = {
607 .release = dynamic_kobj_release,
608 .sysfs_ops = &kobj_sysfs_ops,
612 * kobject_create - create a struct kobject dynamically
614 * This function creates a kobject structure dynamically and sets it up
615 * to be a "dynamic" kobject with a default release function set up.
617 * If the kobject was not able to be created, NULL will be returned.
618 * The kobject structure returned from here must be cleaned up with a
619 * call to kobject_put() and not kfree(), as kobject_init() has
620 * already been called on this structure.
622 struct kobject *kobject_create(void)
624 struct kobject *kobj;
626 kobj = kzalloc(sizeof(*kobj), GFP_KERNEL);
630 kobject_init(kobj, &dynamic_kobj_ktype);
635 * kobject_create_and_add - create a struct kobject dynamically and register it with sysfs
637 * @name: the name for the kset
638 * @parent: the parent kobject of this kobject, if any.
640 * This function creates a kobject structure dynamically and registers it
641 * with sysfs. When you are finished with this structure, call
642 * kobject_put() and the structure will be dynamically freed when
643 * it is no longer being used.
645 * If the kobject was not able to be created, NULL will be returned.
647 struct kobject *kobject_create_and_add(const char *name, struct kobject *parent)
649 struct kobject *kobj;
652 kobj = kobject_create();
656 retval = kobject_add(kobj, parent, "%s", name);
658 printk(KERN_WARNING "%s: kobject_add error: %d\n",
665 EXPORT_SYMBOL_GPL(kobject_create_and_add);
668 * kset_init - initialize a kset for use
671 void kset_init(struct kset *k)
673 kobject_init_internal(&k->kobj);
674 INIT_LIST_HEAD(&k->list);
675 spin_lock_init(&k->list_lock);
678 /* default kobject attribute operations */
679 static ssize_t kobj_attr_show(struct kobject *kobj, struct attribute *attr,
682 struct kobj_attribute *kattr;
685 kattr = container_of(attr, struct kobj_attribute, attr);
687 ret = kattr->show(kobj, kattr, buf);
691 static ssize_t kobj_attr_store(struct kobject *kobj, struct attribute *attr,
692 const char *buf, size_t count)
694 struct kobj_attribute *kattr;
697 kattr = container_of(attr, struct kobj_attribute, attr);
699 ret = kattr->store(kobj, kattr, buf, count);
703 const struct sysfs_ops kobj_sysfs_ops = {
704 .show = kobj_attr_show,
705 .store = kobj_attr_store,
709 * kset_register - initialize and add a kset.
712 int kset_register(struct kset *k)
720 err = kobject_add_internal(&k->kobj);
723 kobject_uevent(&k->kobj, KOBJ_ADD);
728 * kset_unregister - remove a kset.
731 void kset_unregister(struct kset *k)
735 kobject_put(&k->kobj);
739 * kset_find_obj - search for object in kset.
740 * @kset: kset we're looking in.
741 * @name: object's name.
743 * Lock kset via @kset->subsys, and iterate over @kset->list,
744 * looking for a matching kobject. If matching object is found
745 * take a reference and return the object.
747 struct kobject *kset_find_obj(struct kset *kset, const char *name)
750 struct kobject *ret = NULL;
752 spin_lock(&kset->list_lock);
753 list_for_each_entry(k, &kset->list, entry) {
754 if (kobject_name(k) && !strcmp(kobject_name(k), name)) {
755 ret = kobject_get(k);
759 spin_unlock(&kset->list_lock);
763 static void kset_release(struct kobject *kobj)
765 struct kset *kset = container_of(kobj, struct kset, kobj);
766 pr_debug("kobject: '%s' (%p): %s\n",
767 kobject_name(kobj), kobj, __func__);
771 static struct kobj_type kset_ktype = {
772 .sysfs_ops = &kobj_sysfs_ops,
773 .release = kset_release,
777 * kset_create - create a struct kset dynamically
779 * @name: the name for the kset
780 * @uevent_ops: a struct kset_uevent_ops for the kset
781 * @parent_kobj: the parent kobject of this kset, if any.
783 * This function creates a kset structure dynamically. This structure can
784 * then be registered with the system and show up in sysfs with a call to
785 * kset_register(). When you are finished with this structure, if
786 * kset_register() has been called, call kset_unregister() and the
787 * structure will be dynamically freed when it is no longer being used.
789 * If the kset was not able to be created, NULL will be returned.
791 static struct kset *kset_create(const char *name,
792 const struct kset_uevent_ops *uevent_ops,
793 struct kobject *parent_kobj)
798 kset = kzalloc(sizeof(*kset), GFP_KERNEL);
801 retval = kobject_set_name(&kset->kobj, name);
806 kset->uevent_ops = uevent_ops;
807 kset->kobj.parent = parent_kobj;
810 * The kobject of this kset will have a type of kset_ktype and belong to
811 * no kset itself. That way we can properly free it when it is
812 * finished being used.
814 kset->kobj.ktype = &kset_ktype;
815 kset->kobj.kset = NULL;
821 * kset_create_and_add - create a struct kset dynamically and add it to sysfs
823 * @name: the name for the kset
824 * @uevent_ops: a struct kset_uevent_ops for the kset
825 * @parent_kobj: the parent kobject of this kset, if any.
827 * This function creates a kset structure dynamically and registers it
828 * with sysfs. When you are finished with this structure, call
829 * kset_unregister() and the structure will be dynamically freed when it
830 * is no longer being used.
832 * If the kset was not able to be created, NULL will be returned.
834 struct kset *kset_create_and_add(const char *name,
835 const struct kset_uevent_ops *uevent_ops,
836 struct kobject *parent_kobj)
841 kset = kset_create(name, uevent_ops, parent_kobj);
844 error = kset_register(kset);
851 EXPORT_SYMBOL_GPL(kset_create_and_add);
854 static DEFINE_SPINLOCK(kobj_ns_type_lock);
855 static const struct kobj_ns_type_operations *kobj_ns_ops_tbl[KOBJ_NS_TYPES];
857 int kobj_ns_type_register(const struct kobj_ns_type_operations *ops)
859 enum kobj_ns_type type = ops->type;
862 spin_lock(&kobj_ns_type_lock);
865 if (type >= KOBJ_NS_TYPES)
869 if (type <= KOBJ_NS_TYPE_NONE)
873 if (kobj_ns_ops_tbl[type])
877 kobj_ns_ops_tbl[type] = ops;
880 spin_unlock(&kobj_ns_type_lock);
884 int kobj_ns_type_registered(enum kobj_ns_type type)
888 spin_lock(&kobj_ns_type_lock);
889 if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES))
890 registered = kobj_ns_ops_tbl[type] != NULL;
891 spin_unlock(&kobj_ns_type_lock);
896 const struct kobj_ns_type_operations *kobj_child_ns_ops(struct kobject *parent)
898 const struct kobj_ns_type_operations *ops = NULL;
900 if (parent && parent->ktype->child_ns_type)
901 ops = parent->ktype->child_ns_type(parent);
906 const struct kobj_ns_type_operations *kobj_ns_ops(struct kobject *kobj)
908 return kobj_child_ns_ops(kobj->parent);
912 const void *kobj_ns_current(enum kobj_ns_type type)
914 const void *ns = NULL;
916 spin_lock(&kobj_ns_type_lock);
917 if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
918 kobj_ns_ops_tbl[type])
919 ns = kobj_ns_ops_tbl[type]->current_ns();
920 spin_unlock(&kobj_ns_type_lock);
925 const void *kobj_ns_netlink(enum kobj_ns_type type, struct sock *sk)
927 const void *ns = NULL;
929 spin_lock(&kobj_ns_type_lock);
930 if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
931 kobj_ns_ops_tbl[type])
932 ns = kobj_ns_ops_tbl[type]->netlink_ns(sk);
933 spin_unlock(&kobj_ns_type_lock);
938 const void *kobj_ns_initial(enum kobj_ns_type type)
940 const void *ns = NULL;
942 spin_lock(&kobj_ns_type_lock);
943 if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
944 kobj_ns_ops_tbl[type])
945 ns = kobj_ns_ops_tbl[type]->initial_ns();
946 spin_unlock(&kobj_ns_type_lock);
952 * kobj_ns_exit - invalidate a namespace tag
954 * @type: the namespace type (i.e. KOBJ_NS_TYPE_NET)
955 * @ns: the actual namespace being invalidated
957 * This is called when a tag is no longer valid. For instance,
958 * when a network namespace exits, it uses this helper to
959 * make sure no sb's sysfs_info points to the now-invalidated
962 void kobj_ns_exit(enum kobj_ns_type type, const void *ns)
964 sysfs_exit_ns(type, ns);
968 EXPORT_SYMBOL(kobject_get);
969 EXPORT_SYMBOL(kobject_put);
970 EXPORT_SYMBOL(kobject_del);
972 EXPORT_SYMBOL(kset_register);
973 EXPORT_SYMBOL(kset_unregister);