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
)
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 (%p) attempted to be registered with no "
181 parent
= kobject_get(kobj
->parent
);
183 pr_debug("kobject: '%s' (%p): %s: parent: '%s', set: '%s'\n",
184 kobject_name(kobj
), kobj
, __FUNCTION__
,
185 parent
? kobject_name(parent
) : "<NULL>",
186 kobj
->kset
? kobject_name(&kobj
->kset
->kobj
) : "<NULL>" );
189 kobj
->kset
= kset_get(kobj
->kset
);
192 parent
= kobject_get(&kobj
->kset
->kobj
);
194 * If the kset is our parent, get a second
195 * reference, we drop both the kset and the
196 * parent ref on cleanup
201 spin_lock(&kobj
->kset
->list_lock
);
202 list_add_tail(&kobj
->entry
, &kobj
->kset
->list
);
203 spin_unlock(&kobj
->kset
->list_lock
);
204 kobj
->parent
= parent
;
207 error
= create_dir(kobj
);
209 /* unlink does the kobject_put() for us */
213 /* be noisy on error issues */
214 if (error
== -EEXIST
)
215 printk(KERN_ERR
"kobject_add failed for %s with "
216 "-EEXIST, don't try to register things with "
217 "the same name in the same directory.\n",
220 printk(KERN_ERR
"kobject_add failed for %s (%d)\n",
221 kobject_name(kobj
), error
);
229 * kobject_register - initialize and add an object.
230 * @kobj: object in question.
233 int kobject_register(struct kobject
* kobj
)
238 error
= kobject_add(kobj
);
240 kobject_uevent(kobj
, KOBJ_ADD
);
246 * kobject_set_name_vargs - Set the name of an kobject
247 * @kobj: struct kobject to set the name of
248 * @fmt: format string used to build the name
249 * @vargs: vargs to format the string.
251 static int kobject_set_name_vargs(struct kobject
*kobj
, const char *fmt
,
258 name
= kvasprintf(GFP_KERNEL
, fmt
, vargs
);
264 /* Free the old name, if necessary. */
267 /* Now, set the new name */
274 * kobject_set_name - Set the name of a kobject
275 * @kobj: struct kobject to set the name of
276 * @fmt: format string used to build the name
278 * This sets the name of the kobject. If you have already added the
279 * kobject to the system, you must call kobject_rename() in order to
280 * change the name of the kobject.
282 int kobject_set_name(struct kobject
*kobj
, const char *fmt
, ...)
288 retval
= kobject_set_name_vargs(kobj
, fmt
, args
);
293 EXPORT_SYMBOL(kobject_set_name
);
296 * kobject_init_ng - initialize a kobject structure
297 * @kobj: pointer to the kobject to initialize
298 * @ktype: pointer to the ktype for this kobject.
300 * This function will properly initialize a kobject such that it can then
301 * be passed to the kobject_add() call.
303 * After this function is called, the kobject MUST be cleaned up by a call
304 * to kobject_put(), not by a call to kfree directly to ensure that all of
305 * the memory is cleaned up properly.
307 void kobject_init_ng(struct kobject
*kobj
, struct kobj_type
*ktype
)
312 err_str
= "invalid kobject pointer!";
316 err_str
= "must have a ktype to be initialized properly!\n";
319 if (atomic_read(&kobj
->kref
.refcount
)) {
320 /* do not error out as sometimes we can recover */
321 printk(KERN_ERR
"kobject: reference count is already set, "
322 "something is seriously wrong.\n");
326 kref_init(&kobj
->kref
);
327 INIT_LIST_HEAD(&kobj
->entry
);
332 printk(KERN_ERR
"kobject: %s\n", err_str
);
335 EXPORT_SYMBOL(kobject_init_ng
);
337 static int kobject_add_varg(struct kobject
*kobj
, struct kobject
*parent
,
338 const char *fmt
, va_list vargs
)
344 retval
= kobject_set_name_vargs(kobj
, fmt
, aq
);
347 printk(KERN_ERR
"kobject: can not set name properly!\n");
350 kobj
->parent
= parent
;
351 return kobject_add(kobj
);
355 * kobject_add_ng - the main kobject add function
356 * @kobj: the kobject to add
357 * @parent: pointer to the parent of the kobject.
358 * @fmt: format to name the kobject with.
360 * The kobject name is set and added to the kobject hierarchy in this
363 * If @parent is set, then the parent of the @kobj will be set to it.
364 * If @parent is NULL, then the parent of the @kobj will be set to the
365 * kobject associted with the kset assigned to this kobject. If no kset
366 * is assigned to the kobject, then the kobject will be located in the
367 * root of the sysfs tree.
369 * If this function returns an error, kobject_put() must be called to
370 * properly clean up the memory associated with the object.
372 * If the function is successful, the only way to properly clean up the
373 * memory is with a call to kobject_del(), in which case, a call to
374 * kobject_put() is not necessary (kobject_del() does the final
375 * kobject_put() to call the release function in the ktype's release
378 * Under no instance should the kobject that is passed to this function
379 * be directly freed with a call to kfree(), that can leak memory.
381 * Note, no uevent will be created with this call, the caller should set
382 * up all of the necessary sysfs files for the object and then call
383 * kobject_uevent() with the UEVENT_ADD parameter to ensure that
384 * userspace is properly notified of this kobject's creation.
386 int kobject_add_ng(struct kobject
*kobj
, struct kobject
*parent
,
387 const char *fmt
, ...)
396 retval
= kobject_add_varg(kobj
, parent
, fmt
, args
);
401 EXPORT_SYMBOL(kobject_add_ng
);
404 * kobject_init_and_add - initialize a kobject structure and add it to the kobject hierarchy
405 * @kobj: pointer to the kobject to initialize
406 * @ktype: pointer to the ktype for this kobject.
407 * @parent: pointer to the parent of this kobject.
408 * @fmt: the name of the kobject.
410 * This function combines the call to kobject_init_ng() and
411 * kobject_add_ng(). The same type of error handling after a call to
412 * kobject_add_ng() and kobject lifetime rules are the same here.
414 int kobject_init_and_add(struct kobject
*kobj
, struct kobj_type
*ktype
,
415 struct kobject
*parent
, const char *fmt
, ...)
420 kobject_init_ng(kobj
, ktype
);
423 retval
= kobject_add_varg(kobj
, parent
, fmt
, args
);
428 EXPORT_SYMBOL_GPL(kobject_init_and_add
);
431 * kobject_rename - change the name of an object
432 * @kobj: object in question.
433 * @new_name: object's new name
436 int kobject_rename(struct kobject
* kobj
, const char *new_name
)
439 const char *devpath
= NULL
;
440 char *devpath_string
= NULL
;
443 kobj
= kobject_get(kobj
);
449 /* see if this name is already in use */
451 struct kobject
*temp_kobj
;
452 temp_kobj
= kset_find_obj(kobj
->kset
, new_name
);
454 printk(KERN_WARNING
"kobject '%s' cannot be renamed "
455 "to '%s' as '%s' is already in existence.\n",
456 kobject_name(kobj
), new_name
, new_name
);
457 kobject_put(temp_kobj
);
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
;
476 error
= sysfs_rename_dir(kobj
, new_name
);
478 /* This function is mostly/only used for network interface.
479 * Some hotplug package track interfaces by their name and
480 * therefore want to know when the name is changed by the user. */
482 kobject_uevent_env(kobj
, KOBJ_MOVE
, envp
);
485 kfree(devpath_string
);
493 * kobject_move - move object to another parent
494 * @kobj: object in question.
495 * @new_parent: object's new parent (can be NULL)
498 int kobject_move(struct kobject
*kobj
, struct kobject
*new_parent
)
501 struct kobject
*old_parent
;
502 const char *devpath
= NULL
;
503 char *devpath_string
= NULL
;
506 kobj
= kobject_get(kobj
);
509 new_parent
= kobject_get(new_parent
);
512 new_parent
= kobject_get(&kobj
->kset
->kobj
);
514 /* old object path */
515 devpath
= kobject_get_path(kobj
, GFP_KERNEL
);
520 devpath_string
= kmalloc(strlen(devpath
) + 15, GFP_KERNEL
);
521 if (!devpath_string
) {
525 sprintf(devpath_string
, "DEVPATH_OLD=%s", devpath
);
526 envp
[0] = devpath_string
;
528 error
= sysfs_move_dir(kobj
, new_parent
);
531 old_parent
= kobj
->parent
;
532 kobj
->parent
= new_parent
;
534 kobject_put(old_parent
);
535 kobject_uevent_env(kobj
, KOBJ_MOVE
, envp
);
537 kobject_put(new_parent
);
539 kfree(devpath_string
);
545 * kobject_del - unlink kobject from hierarchy.
549 void kobject_del(struct kobject
* kobj
)
553 sysfs_remove_dir(kobj
);
558 * kobject_unregister - remove object from hierarchy and decrement refcount.
559 * @kobj: object going away.
562 void kobject_unregister(struct kobject
* kobj
)
566 pr_debug("kobject: '%s' (%p): %s\n",
567 kobject_name(kobj
), kobj
, __FUNCTION__
);
568 kobject_uevent(kobj
, KOBJ_REMOVE
);
574 * kobject_get - increment refcount for object.
578 struct kobject
* kobject_get(struct kobject
* kobj
)
581 kref_get(&kobj
->kref
);
586 * kobject_cleanup - free kobject resources.
587 * @kobj: object to cleanup
589 static void kobject_cleanup(struct kobject
*kobj
)
591 struct kobj_type
* t
= get_ktype(kobj
);
592 struct kset
* s
= kobj
->kset
;
593 struct kobject
* parent
= kobj
->parent
;
594 const char *name
= kobj
->k_name
;
596 pr_debug("kobject: '%s' (%p): %s\n",
597 kobject_name(kobj
), kobj
, __FUNCTION__
);
598 if (t
&& t
->release
) {
600 /* If we have a release function, we can guess that this was
601 * not a statically allocated kobject, so we should be safe to
610 static void kobject_release(struct kref
*kref
)
612 kobject_cleanup(container_of(kref
, struct kobject
, kref
));
616 * kobject_put - decrement refcount for object.
619 * Decrement the refcount, and if 0, call kobject_cleanup().
621 void kobject_put(struct kobject
* kobj
)
624 kref_put(&kobj
->kref
, kobject_release
);
627 static void dynamic_kobj_release(struct kobject
*kobj
)
629 pr_debug("kobject: '%s' (%p): %s\n",
630 kobject_name(kobj
), kobj
, __FUNCTION__
);
634 static struct kobj_type dynamic_kobj_ktype
= {
635 .release
= dynamic_kobj_release
,
636 .sysfs_ops
= &kobj_sysfs_ops
,
640 * kobject_create - create a struct kobject dynamically
642 * This function creates a kobject structure dynamically and sets it up
643 * to be a "dynamic" kobject with a default release function set up.
645 * If the kobject was not able to be created, NULL will be returned.
646 * The kobject structure returned from here must be cleaned up with a
647 * call to kobject_put() and not kfree(), as kobject_init_ng() has
648 * already been called on this structure.
650 struct kobject
*kobject_create(void)
652 struct kobject
*kobj
;
654 kobj
= kzalloc(sizeof(*kobj
), GFP_KERNEL
);
658 kobject_init_ng(kobj
, &dynamic_kobj_ktype
);
663 * kobject_create_and_add - create a struct kobject dynamically and register it with sysfs
665 * @name: the name for the kset
666 * @parent: the parent kobject of this kobject, if any.
668 * This function creates a kset structure dynamically and registers it
669 * with sysfs. When you are finished with this structure, call
670 * kobject_unregister() and the structure will be dynamically freed when
671 * it is no longer being used.
673 * If the kobject was not able to be created, NULL will be returned.
675 struct kobject
*kobject_create_and_add(const char *name
, struct kobject
*parent
)
677 struct kobject
*kobj
;
680 kobj
= kobject_create();
684 retval
= kobject_add_ng(kobj
, parent
, "%s", name
);
686 printk(KERN_WARNING
"%s: kobject_add error: %d\n",
687 __FUNCTION__
, retval
);
693 EXPORT_SYMBOL_GPL(kobject_create_and_add
);
696 * kset_init - initialize a kset for use
700 void kset_init(struct kset
* k
)
702 kobject_init(&k
->kobj
);
703 INIT_LIST_HEAD(&k
->list
);
704 spin_lock_init(&k
->list_lock
);
707 /* default kobject attribute operations */
708 static ssize_t
kobj_attr_show(struct kobject
*kobj
, struct attribute
*attr
,
711 struct kobj_attribute
*kattr
;
714 kattr
= container_of(attr
, struct kobj_attribute
, attr
);
716 ret
= kattr
->show(kobj
, kattr
, buf
);
720 static ssize_t
kobj_attr_store(struct kobject
*kobj
, struct attribute
*attr
,
721 const char *buf
, size_t count
)
723 struct kobj_attribute
*kattr
;
726 kattr
= container_of(attr
, struct kobj_attribute
, attr
);
728 ret
= kattr
->store(kobj
, kattr
, buf
, count
);
732 struct sysfs_ops kobj_sysfs_ops
= {
733 .show
= kobj_attr_show
,
734 .store
= kobj_attr_store
,
738 * kset_add - add a kset object to the hierarchy.
742 int kset_add(struct kset
* k
)
744 return kobject_add(&k
->kobj
);
749 * kset_register - initialize and add a kset.
753 int kset_register(struct kset
* k
)
764 kobject_uevent(&k
->kobj
, KOBJ_ADD
);
770 * kset_unregister - remove a kset.
774 void kset_unregister(struct kset
* k
)
778 kobject_unregister(&k
->kobj
);
783 * kset_find_obj - search for object in kset.
784 * @kset: kset we're looking in.
785 * @name: object's name.
787 * Lock kset via @kset->subsys, and iterate over @kset->list,
788 * looking for a matching kobject. If matching object is found
789 * take a reference and return the object.
792 struct kobject
* kset_find_obj(struct kset
* kset
, const char * name
)
794 struct list_head
* entry
;
795 struct kobject
* ret
= NULL
;
797 spin_lock(&kset
->list_lock
);
798 list_for_each(entry
,&kset
->list
) {
799 struct kobject
* k
= to_kobj(entry
);
800 if (kobject_name(k
) && !strcmp(kobject_name(k
),name
)) {
801 ret
= kobject_get(k
);
805 spin_unlock(&kset
->list_lock
);
809 static void kset_release(struct kobject
*kobj
)
811 struct kset
*kset
= container_of(kobj
, struct kset
, kobj
);
812 pr_debug("kobject: '%s' (%p): %s\n",
813 kobject_name(kobj
), kobj
, __FUNCTION__
);
817 static struct kobj_type kset_ktype
= {
818 .sysfs_ops
= &kobj_sysfs_ops
,
819 .release
= kset_release
,
823 * kset_create - create a struct kset dynamically
825 * @name: the name for the kset
826 * @uevent_ops: a struct kset_uevent_ops for the kset
827 * @parent_kobj: the parent kobject of this kset, if any.
829 * This function creates a kset structure dynamically. This structure can
830 * then be registered with the system and show up in sysfs with a call to
831 * kset_register(). When you are finished with this structure, if
832 * kset_register() has been called, call kset_unregister() and the
833 * structure will be dynamically freed when it is no longer being used.
835 * If the kset was not able to be created, NULL will be returned.
837 static struct kset
*kset_create(const char *name
,
838 struct kset_uevent_ops
*uevent_ops
,
839 struct kobject
*parent_kobj
)
843 kset
= kzalloc(sizeof(*kset
), GFP_KERNEL
);
846 kobject_set_name(&kset
->kobj
, name
);
847 kset
->uevent_ops
= uevent_ops
;
848 kset
->kobj
.parent
= parent_kobj
;
851 * The kobject of this kset will have a type of kset_ktype and belong to
852 * no kset itself. That way we can properly free it when it is
853 * finished being used.
855 kset
->kobj
.ktype
= &kset_ktype
;
856 kset
->kobj
.kset
= NULL
;
862 * kset_create_and_add - create a struct kset dynamically and add it to sysfs
864 * @name: the name for the kset
865 * @uevent_ops: a struct kset_uevent_ops for the kset
866 * @parent_kobj: the parent kobject of this kset, if any.
868 * This function creates a kset structure dynamically and registers it
869 * with sysfs. When you are finished with this structure, call
870 * kset_unregister() and the structure will be dynamically freed when it
871 * is no longer being used.
873 * If the kset was not able to be created, NULL will be returned.
875 struct kset
*kset_create_and_add(const char *name
,
876 struct kset_uevent_ops
*uevent_ops
,
877 struct kobject
*parent_kobj
)
882 kset
= kset_create(name
, uevent_ops
, parent_kobj
);
885 error
= kset_register(kset
);
892 EXPORT_SYMBOL_GPL(kset_create_and_add
);
894 EXPORT_SYMBOL(kobject_init
);
895 EXPORT_SYMBOL(kobject_register
);
896 EXPORT_SYMBOL(kobject_unregister
);
897 EXPORT_SYMBOL(kobject_get
);
898 EXPORT_SYMBOL(kobject_put
);
899 EXPORT_SYMBOL(kobject_add
);
900 EXPORT_SYMBOL(kobject_del
);
902 EXPORT_SYMBOL(kset_register
);
903 EXPORT_SYMBOL(kset_unregister
);