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_internal() 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
);
164 static int kobject_add_internal(struct kobject
*kobj
)
167 struct kobject
* parent
;
169 if (!(kobj
= kobject_get(kobj
)))
172 kobject_set_name(kobj
, "NO_NAME");
173 if (!*kobj
->k_name
) {
174 pr_debug("kobject (%p) attempted to be registered with no "
180 parent
= kobject_get(kobj
->parent
);
182 pr_debug("kobject: '%s' (%p): %s: parent: '%s', set: '%s'\n",
183 kobject_name(kobj
), kobj
, __FUNCTION__
,
184 parent
? kobject_name(parent
) : "<NULL>",
185 kobj
->kset
? kobject_name(&kobj
->kset
->kobj
) : "<NULL>" );
188 kobj
->kset
= kset_get(kobj
->kset
);
191 parent
= kobject_get(&kobj
->kset
->kobj
);
193 * If the kset is our parent, get a second
194 * reference, we drop both the kset and the
195 * parent ref on cleanup
200 spin_lock(&kobj
->kset
->list_lock
);
201 list_add_tail(&kobj
->entry
, &kobj
->kset
->list
);
202 spin_unlock(&kobj
->kset
->list_lock
);
203 kobj
->parent
= parent
;
206 error
= create_dir(kobj
);
208 /* unlink does the kobject_put() for us */
211 /* be noisy on error issues */
212 if (error
== -EEXIST
)
213 printk(KERN_ERR
"%s failed for %s with "
214 "-EEXIST, don't try to register things with "
215 "the same name in the same directory.\n",
216 __FUNCTION__
, kobject_name(kobj
));
218 printk(KERN_ERR
"%s failed for %s (%d)\n",
219 __FUNCTION__
, kobject_name(kobj
), error
);
227 * kobject_register - initialize and add an object.
228 * @kobj: object in question.
231 int kobject_register(struct kobject
* kobj
)
236 error
= kobject_add(kobj
);
238 kobject_uevent(kobj
, KOBJ_ADD
);
244 * kobject_set_name_vargs - Set the name of an kobject
245 * @kobj: struct kobject to set the name of
246 * @fmt: format string used to build the name
247 * @vargs: vargs to format the string.
249 static int kobject_set_name_vargs(struct kobject
*kobj
, const char *fmt
,
256 name
= kvasprintf(GFP_KERNEL
, fmt
, vargs
);
262 /* Free the old name, if necessary. */
265 /* Now, set the new name */
272 * kobject_set_name - Set the name of a kobject
273 * @kobj: struct kobject to set the name of
274 * @fmt: format string used to build the name
276 * This sets the name of the kobject. If you have already added the
277 * kobject to the system, you must call kobject_rename() in order to
278 * change the name of the kobject.
280 int kobject_set_name(struct kobject
*kobj
, const char *fmt
, ...)
286 retval
= kobject_set_name_vargs(kobj
, fmt
, args
);
291 EXPORT_SYMBOL(kobject_set_name
);
294 * kobject_init_ng - initialize a kobject structure
295 * @kobj: pointer to the kobject to initialize
296 * @ktype: pointer to the ktype for this kobject.
298 * This function will properly initialize a kobject such that it can then
299 * be passed to the kobject_add() call.
301 * After this function is called, the kobject MUST be cleaned up by a call
302 * to kobject_put(), not by a call to kfree directly to ensure that all of
303 * the memory is cleaned up properly.
305 void kobject_init_ng(struct kobject
*kobj
, struct kobj_type
*ktype
)
310 err_str
= "invalid kobject pointer!";
314 err_str
= "must have a ktype to be initialized properly!\n";
317 if (atomic_read(&kobj
->kref
.refcount
)) {
318 /* do not error out as sometimes we can recover */
319 printk(KERN_ERR
"kobject: reference count is already set, "
320 "something is seriously wrong.\n");
324 kref_init(&kobj
->kref
);
325 INIT_LIST_HEAD(&kobj
->entry
);
330 printk(KERN_ERR
"kobject: %s\n", err_str
);
333 EXPORT_SYMBOL(kobject_init_ng
);
335 static int kobject_add_varg(struct kobject
*kobj
, struct kobject
*parent
,
336 const char *fmt
, va_list vargs
)
342 retval
= kobject_set_name_vargs(kobj
, fmt
, aq
);
345 printk(KERN_ERR
"kobject: can not set name properly!\n");
348 kobj
->parent
= parent
;
349 return kobject_add_internal(kobj
);
353 * kobject_add - the main kobject add function
354 * @kobj: the kobject to add
355 * @parent: pointer to the parent of the kobject.
356 * @fmt: format to name the kobject with.
358 * The kobject name is set and added to the kobject hierarchy in this
361 * If @parent is set, then the parent of the @kobj will be set to it.
362 * If @parent is NULL, then the parent of the @kobj will be set to the
363 * kobject associted with the kset assigned to this kobject. If no kset
364 * is assigned to the kobject, then the kobject will be located in the
365 * root of the sysfs tree.
367 * If this function returns an error, kobject_put() must be called to
368 * properly clean up the memory associated with the object.
370 * If the function is successful, the only way to properly clean up the
371 * memory is with a call to kobject_del(), in which case, a call to
372 * kobject_put() is not necessary (kobject_del() does the final
373 * kobject_put() to call the release function in the ktype's release
376 * Under no instance should the kobject that is passed to this function
377 * be directly freed with a call to kfree(), that can leak memory.
379 * Note, no uevent will be created with this call, the caller should set
380 * up all of the necessary sysfs files for the object and then call
381 * kobject_uevent() with the UEVENT_ADD parameter to ensure that
382 * userspace is properly notified of this kobject's creation.
384 int kobject_add(struct kobject
*kobj
, struct kobject
*parent
,
385 const char *fmt
, ...)
394 retval
= kobject_add_varg(kobj
, parent
, fmt
, args
);
399 EXPORT_SYMBOL(kobject_add
);
402 * kobject_init_and_add - initialize a kobject structure and add it to the kobject hierarchy
403 * @kobj: pointer to the kobject to initialize
404 * @ktype: pointer to the ktype for this kobject.
405 * @parent: pointer to the parent of this kobject.
406 * @fmt: the name of the kobject.
408 * This function combines the call to kobject_init_ng() and
409 * kobject_add(). The same type of error handling after a call to
410 * kobject_add() and kobject lifetime rules are the same here.
412 int kobject_init_and_add(struct kobject
*kobj
, struct kobj_type
*ktype
,
413 struct kobject
*parent
, const char *fmt
, ...)
418 kobject_init_ng(kobj
, ktype
);
421 retval
= kobject_add_varg(kobj
, parent
, fmt
, args
);
426 EXPORT_SYMBOL_GPL(kobject_init_and_add
);
429 * kobject_rename - change the name of an object
430 * @kobj: object in question.
431 * @new_name: object's new name
434 int kobject_rename(struct kobject
* kobj
, const char *new_name
)
437 const char *devpath
= NULL
;
438 char *devpath_string
= NULL
;
441 kobj
= kobject_get(kobj
);
447 /* see if this name is already in use */
449 struct kobject
*temp_kobj
;
450 temp_kobj
= kset_find_obj(kobj
->kset
, new_name
);
452 printk(KERN_WARNING
"kobject '%s' cannot be renamed "
453 "to '%s' as '%s' is already in existence.\n",
454 kobject_name(kobj
), new_name
, new_name
);
455 kobject_put(temp_kobj
);
460 devpath
= kobject_get_path(kobj
, GFP_KERNEL
);
465 devpath_string
= kmalloc(strlen(devpath
) + 15, GFP_KERNEL
);
466 if (!devpath_string
) {
470 sprintf(devpath_string
, "DEVPATH_OLD=%s", devpath
);
471 envp
[0] = devpath_string
;
474 error
= sysfs_rename_dir(kobj
, new_name
);
476 /* This function is mostly/only used for network interface.
477 * Some hotplug package track interfaces by their name and
478 * therefore want to know when the name is changed by the user. */
480 kobject_uevent_env(kobj
, KOBJ_MOVE
, envp
);
483 kfree(devpath_string
);
491 * kobject_move - move object to another parent
492 * @kobj: object in question.
493 * @new_parent: object's new parent (can be NULL)
496 int kobject_move(struct kobject
*kobj
, struct kobject
*new_parent
)
499 struct kobject
*old_parent
;
500 const char *devpath
= NULL
;
501 char *devpath_string
= NULL
;
504 kobj
= kobject_get(kobj
);
507 new_parent
= kobject_get(new_parent
);
510 new_parent
= kobject_get(&kobj
->kset
->kobj
);
512 /* old object path */
513 devpath
= kobject_get_path(kobj
, GFP_KERNEL
);
518 devpath_string
= kmalloc(strlen(devpath
) + 15, GFP_KERNEL
);
519 if (!devpath_string
) {
523 sprintf(devpath_string
, "DEVPATH_OLD=%s", devpath
);
524 envp
[0] = devpath_string
;
526 error
= sysfs_move_dir(kobj
, new_parent
);
529 old_parent
= kobj
->parent
;
530 kobj
->parent
= new_parent
;
532 kobject_put(old_parent
);
533 kobject_uevent_env(kobj
, KOBJ_MOVE
, envp
);
535 kobject_put(new_parent
);
537 kfree(devpath_string
);
543 * kobject_del - unlink kobject from hierarchy.
547 void kobject_del(struct kobject
* kobj
)
551 sysfs_remove_dir(kobj
);
556 * kobject_unregister - remove object from hierarchy and decrement refcount.
557 * @kobj: object going away.
560 void kobject_unregister(struct kobject
* kobj
)
564 pr_debug("kobject: '%s' (%p): %s\n",
565 kobject_name(kobj
), kobj
, __FUNCTION__
);
566 kobject_uevent(kobj
, KOBJ_REMOVE
);
572 * kobject_get - increment refcount for object.
576 struct kobject
* kobject_get(struct kobject
* kobj
)
579 kref_get(&kobj
->kref
);
584 * kobject_cleanup - free kobject resources.
585 * @kobj: object to cleanup
587 static void kobject_cleanup(struct kobject
*kobj
)
589 struct kobj_type
* t
= get_ktype(kobj
);
590 struct kset
* s
= kobj
->kset
;
591 const char *name
= kobj
->k_name
;
593 pr_debug("kobject: '%s' (%p): %s\n",
594 kobject_name(kobj
), kobj
, __FUNCTION__
);
595 if (t
&& t
->release
) {
597 /* If we have a release function, we can guess that this was
598 * not a statically allocated kobject, so we should be safe to
606 static void kobject_release(struct kref
*kref
)
608 kobject_cleanup(container_of(kref
, struct kobject
, kref
));
612 * kobject_put - decrement refcount for object.
615 * Decrement the refcount, and if 0, call kobject_cleanup().
617 void kobject_put(struct kobject
* kobj
)
620 kref_put(&kobj
->kref
, kobject_release
);
623 static void dynamic_kobj_release(struct kobject
*kobj
)
625 pr_debug("kobject: '%s' (%p): %s\n",
626 kobject_name(kobj
), kobj
, __FUNCTION__
);
630 static struct kobj_type dynamic_kobj_ktype
= {
631 .release
= dynamic_kobj_release
,
632 .sysfs_ops
= &kobj_sysfs_ops
,
636 * kobject_create - create a struct kobject dynamically
638 * This function creates a kobject structure dynamically and sets it up
639 * to be a "dynamic" kobject with a default release function set up.
641 * If the kobject was not able to be created, NULL will be returned.
642 * The kobject structure returned from here must be cleaned up with a
643 * call to kobject_put() and not kfree(), as kobject_init_ng() has
644 * already been called on this structure.
646 struct kobject
*kobject_create(void)
648 struct kobject
*kobj
;
650 kobj
= kzalloc(sizeof(*kobj
), GFP_KERNEL
);
654 kobject_init_ng(kobj
, &dynamic_kobj_ktype
);
659 * kobject_create_and_add - create a struct kobject dynamically and register it with sysfs
661 * @name: the name for the kset
662 * @parent: the parent kobject of this kobject, if any.
664 * This function creates a kset structure dynamically and registers it
665 * with sysfs. When you are finished with this structure, call
666 * kobject_unregister() and the structure will be dynamically freed when
667 * it is no longer being used.
669 * If the kobject was not able to be created, NULL will be returned.
671 struct kobject
*kobject_create_and_add(const char *name
, struct kobject
*parent
)
673 struct kobject
*kobj
;
676 kobj
= kobject_create();
680 retval
= kobject_add(kobj
, parent
, "%s", name
);
682 printk(KERN_WARNING
"%s: kobject_add error: %d\n",
683 __FUNCTION__
, retval
);
689 EXPORT_SYMBOL_GPL(kobject_create_and_add
);
692 * kset_init - initialize a kset for use
696 void kset_init(struct kset
* k
)
698 kobject_init(&k
->kobj
);
699 INIT_LIST_HEAD(&k
->list
);
700 spin_lock_init(&k
->list_lock
);
703 /* default kobject attribute operations */
704 static ssize_t
kobj_attr_show(struct kobject
*kobj
, struct attribute
*attr
,
707 struct kobj_attribute
*kattr
;
710 kattr
= container_of(attr
, struct kobj_attribute
, attr
);
712 ret
= kattr
->show(kobj
, kattr
, buf
);
716 static ssize_t
kobj_attr_store(struct kobject
*kobj
, struct attribute
*attr
,
717 const char *buf
, size_t count
)
719 struct kobj_attribute
*kattr
;
722 kattr
= container_of(attr
, struct kobj_attribute
, attr
);
724 ret
= kattr
->store(kobj
, kattr
, buf
, count
);
728 struct sysfs_ops kobj_sysfs_ops
= {
729 .show
= kobj_attr_show
,
730 .store
= kobj_attr_store
,
734 * kset_add - add a kset object to the hierarchy.
738 int kset_add(struct kset
* k
)
740 return kobject_add_internal(&k
->kobj
);
745 * kset_register - initialize and add a kset.
749 int kset_register(struct kset
* k
)
760 kobject_uevent(&k
->kobj
, KOBJ_ADD
);
766 * kset_unregister - remove a kset.
770 void kset_unregister(struct kset
* k
)
774 kobject_unregister(&k
->kobj
);
779 * kset_find_obj - search for object in kset.
780 * @kset: kset we're looking in.
781 * @name: object's name.
783 * Lock kset via @kset->subsys, and iterate over @kset->list,
784 * looking for a matching kobject. If matching object is found
785 * take a reference and return the object.
788 struct kobject
* kset_find_obj(struct kset
* kset
, const char * name
)
790 struct list_head
* entry
;
791 struct kobject
* ret
= NULL
;
793 spin_lock(&kset
->list_lock
);
794 list_for_each(entry
,&kset
->list
) {
795 struct kobject
* k
= to_kobj(entry
);
796 if (kobject_name(k
) && !strcmp(kobject_name(k
),name
)) {
797 ret
= kobject_get(k
);
801 spin_unlock(&kset
->list_lock
);
805 static void kset_release(struct kobject
*kobj
)
807 struct kset
*kset
= container_of(kobj
, struct kset
, kobj
);
808 pr_debug("kobject: '%s' (%p): %s\n",
809 kobject_name(kobj
), kobj
, __FUNCTION__
);
813 static struct kobj_type kset_ktype
= {
814 .sysfs_ops
= &kobj_sysfs_ops
,
815 .release
= kset_release
,
819 * kset_create - create a struct kset dynamically
821 * @name: the name for the kset
822 * @uevent_ops: a struct kset_uevent_ops for the kset
823 * @parent_kobj: the parent kobject of this kset, if any.
825 * This function creates a kset structure dynamically. This structure can
826 * then be registered with the system and show up in sysfs with a call to
827 * kset_register(). When you are finished with this structure, if
828 * kset_register() has been called, call kset_unregister() and the
829 * structure will be dynamically freed when it is no longer being used.
831 * If the kset was not able to be created, NULL will be returned.
833 static struct kset
*kset_create(const char *name
,
834 struct kset_uevent_ops
*uevent_ops
,
835 struct kobject
*parent_kobj
)
839 kset
= kzalloc(sizeof(*kset
), GFP_KERNEL
);
842 kobject_set_name(&kset
->kobj
, name
);
843 kset
->uevent_ops
= uevent_ops
;
844 kset
->kobj
.parent
= parent_kobj
;
847 * The kobject of this kset will have a type of kset_ktype and belong to
848 * no kset itself. That way we can properly free it when it is
849 * finished being used.
851 kset
->kobj
.ktype
= &kset_ktype
;
852 kset
->kobj
.kset
= NULL
;
858 * kset_create_and_add - create a struct kset dynamically and add it to sysfs
860 * @name: the name for the kset
861 * @uevent_ops: a struct kset_uevent_ops for the kset
862 * @parent_kobj: the parent kobject of this kset, if any.
864 * This function creates a kset structure dynamically and registers it
865 * with sysfs. When you are finished with this structure, call
866 * kset_unregister() and the structure will be dynamically freed when it
867 * is no longer being used.
869 * If the kset was not able to be created, NULL will be returned.
871 struct kset
*kset_create_and_add(const char *name
,
872 struct kset_uevent_ops
*uevent_ops
,
873 struct kobject
*parent_kobj
)
878 kset
= kset_create(name
, uevent_ops
, parent_kobj
);
881 error
= kset_register(kset
);
888 EXPORT_SYMBOL_GPL(kset_create_and_add
);
890 EXPORT_SYMBOL(kobject_init
);
891 EXPORT_SYMBOL(kobject_register
);
892 EXPORT_SYMBOL(kobject_unregister
);
893 EXPORT_SYMBOL(kobject_get
);
894 EXPORT_SYMBOL(kobject_put
);
895 EXPORT_SYMBOL(kobject_del
);
897 EXPORT_SYMBOL(kset_register
);
898 EXPORT_SYMBOL(kset_unregister
);