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("%s: path = '%s'\n",__FUNCTION__
,path
);
102 * kobject_get_path - generate and return the path associated with a given kobj and kset pair.
104 * @kobj: kobject in question, with which to build the path
105 * @gfp_mask: the allocation type used to allocate the path
107 * The result must be freed by the caller with kfree().
109 char *kobject_get_path(struct kobject
*kobj
, gfp_t gfp_mask
)
114 len
= get_kobj_path_length(kobj
);
117 path
= kzalloc(len
, gfp_mask
);
120 fill_kobj_path(kobj
, path
, len
);
124 EXPORT_SYMBOL_GPL(kobject_get_path
);
127 * kobject_init - initialize object.
128 * @kobj: object in question.
130 void kobject_init(struct kobject
* kobj
)
134 kref_init(&kobj
->kref
);
135 INIT_LIST_HEAD(&kobj
->entry
);
136 kobj
->kset
= kset_get(kobj
->kset
);
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 attempted to be registered with no name!\n");
180 parent
= kobject_get(kobj
->parent
);
182 pr_debug("kobject %s: registering. parent: %s, set: %s\n",
183 kobject_name(kobj
), parent
? kobject_name(parent
) : "<NULL>",
184 kobj
->kset
? kobject_name(&kobj
->kset
->kobj
) : "<NULL>" );
187 spin_lock(&kobj
->kset
->list_lock
);
190 parent
= kobject_get(&kobj
->kset
->kobj
);
192 * If the kset is our parent, get a second
193 * reference, we drop both the kset and the
194 * parent ref on cleanup
199 list_add_tail(&kobj
->entry
,&kobj
->kset
->list
);
200 spin_unlock(&kobj
->kset
->list_lock
);
201 kobj
->parent
= parent
;
204 error
= create_dir(kobj
);
206 /* unlink does the kobject_put() for us */
210 /* be noisy on error issues */
211 if (error
== -EEXIST
)
212 printk(KERN_ERR
"kobject_add failed for %s with "
213 "-EEXIST, don't try to register things with "
214 "the same name in the same directory.\n",
217 printk(KERN_ERR
"kobject_add failed for %s (%d)\n",
218 kobject_name(kobj
), error
);
226 * kobject_register - initialize and add an object.
227 * @kobj: object in question.
230 int kobject_register(struct kobject
* kobj
)
235 error
= kobject_add(kobj
);
237 kobject_uevent(kobj
, KOBJ_ADD
);
243 * kobject_set_name_vargs - Set the name of an kobject
244 * @kobj: struct kobject to set the name of
245 * @fmt: format string used to build the name
246 * @vargs: vargs to format the string.
248 static int kobject_set_name_vargs(struct kobject
*kobj
, const char *fmt
,
255 name
= kvasprintf(GFP_KERNEL
, fmt
, vargs
);
261 /* Free the old name, if necessary. */
264 /* Now, set the new name */
271 * kobject_set_name - Set the name of a kobject
272 * @kobj: struct kobject to set the name of
273 * @fmt: format string used to build the name
275 * This sets the name of the kobject. If you have already added the
276 * kobject to the system, you must call kobject_rename() in order to
277 * change the name of the kobject.
279 int kobject_set_name(struct kobject
*kobj
, const char *fmt
, ...)
285 retval
= kobject_set_name_vargs(kobj
, fmt
, args
);
290 EXPORT_SYMBOL(kobject_set_name
);
293 * kobject_init_ng - initialize a kobject structure
294 * @kobj: pointer to the kobject to initialize
295 * @ktype: pointer to the ktype for this kobject.
297 * This function will properly initialize a kobject such that it can then
298 * be passed to the kobject_add() call.
300 * After this function is called, the kobject MUST be cleaned up by a call
301 * to kobject_put(), not by a call to kfree directly to ensure that all of
302 * the memory is cleaned up properly.
304 void kobject_init_ng(struct kobject
*kobj
, struct kobj_type
*ktype
)
309 err_str
= "invalid kobject pointer!";
313 err_str
= "must have a ktype to be initialized properly!\n";
316 if (atomic_read(&kobj
->kref
.refcount
)) {
317 /* do not error out as sometimes we can recover */
318 printk(KERN_ERR
"kobject: reference count is already set, "
319 "something is seriously wrong.\n");
323 kref_init(&kobj
->kref
);
324 INIT_LIST_HEAD(&kobj
->entry
);
329 printk(KERN_ERR
"kobject: %s\n", err_str
);
332 EXPORT_SYMBOL(kobject_init_ng
);
334 static int kobject_add_varg(struct kobject
*kobj
, struct kobject
*parent
,
335 const char *fmt
, va_list vargs
)
341 retval
= kobject_set_name_vargs(kobj
, fmt
, aq
);
344 printk(KERN_ERR
"kobject: can not set name properly!\n");
347 kobj
->parent
= parent
;
348 return kobject_add(kobj
);
352 * kobject_add_ng - the main kobject add function
353 * @kobj: the kobject to add
354 * @parent: pointer to the parent of the kobject.
355 * @fmt: format to name the kobject with.
357 * The kobject name is set and added to the kobject hierarchy in this
360 * If @parent is set, then the parent of the @kobj will be set to it.
361 * If @parent is NULL, then the parent of the @kobj will be set to the
362 * kobject associted with the kset assigned to this kobject. If no kset
363 * is assigned to the kobject, then the kobject will be located in the
364 * root of the sysfs tree.
366 * If this function returns an error, kobject_put() must be called to
367 * properly clean up the memory associated with the object.
369 * If the function is successful, the only way to properly clean up the
370 * memory is with a call to kobject_del(), in which case, a call to
371 * kobject_put() is not necessary (kobject_del() does the final
372 * kobject_put() to call the release function in the ktype's release
375 * Under no instance should the kobject that is passed to this function
376 * be directly freed with a call to kfree(), that can leak memory.
378 * Note, no uevent will be created with this call, the caller should set
379 * up all of the necessary sysfs files for the object and then call
380 * kobject_uevent() with the UEVENT_ADD parameter to ensure that
381 * userspace is properly notified of this kobject's creation.
383 int kobject_add_ng(struct kobject
*kobj
, struct kobject
*parent
,
384 const char *fmt
, ...)
393 retval
= kobject_add_varg(kobj
, parent
, fmt
, args
);
398 EXPORT_SYMBOL(kobject_add_ng
);
401 * kobject_init_and_add - initialize a kobject structure and add it to the kobject hierarchy
402 * @kobj: pointer to the kobject to initialize
403 * @ktype: pointer to the ktype for this kobject.
404 * @parent: pointer to the parent of this kobject.
405 * @fmt: the name of the kobject.
407 * This function combines the call to kobject_init_ng() and
408 * kobject_add_ng(). The same type of error handling after a call to
409 * kobject_add_ng() and kobject lifetime rules are the same here.
411 int kobject_init_and_add(struct kobject
*kobj
, struct kobj_type
*ktype
,
412 struct kobject
*parent
, const char *fmt
, ...)
417 kobject_init_ng(kobj
, ktype
);
420 retval
= kobject_add_varg(kobj
, parent
, fmt
, args
);
425 EXPORT_SYMBOL_GPL(kobject_init_and_add
);
428 * kobject_rename - change the name of an object
429 * @kobj: object in question.
430 * @new_name: object's new name
433 int kobject_rename(struct kobject
* kobj
, const char *new_name
)
436 const char *devpath
= NULL
;
437 char *devpath_string
= NULL
;
440 kobj
= kobject_get(kobj
);
446 /* see if this name is already in use */
448 struct kobject
*temp_kobj
;
449 temp_kobj
= kset_find_obj(kobj
->kset
, new_name
);
451 printk(KERN_WARNING
"kobject '%s' cannot be renamed "
452 "to '%s' as '%s' is already in existence.\n",
453 kobject_name(kobj
), new_name
, new_name
);
454 kobject_put(temp_kobj
);
459 devpath
= kobject_get_path(kobj
, GFP_KERNEL
);
464 devpath_string
= kmalloc(strlen(devpath
) + 15, GFP_KERNEL
);
465 if (!devpath_string
) {
469 sprintf(devpath_string
, "DEVPATH_OLD=%s", devpath
);
470 envp
[0] = devpath_string
;
473 error
= sysfs_rename_dir(kobj
, new_name
);
475 /* This function is mostly/only used for network interface.
476 * Some hotplug package track interfaces by their name and
477 * therefore want to know when the name is changed by the user. */
479 kobject_uevent_env(kobj
, KOBJ_MOVE
, envp
);
482 kfree(devpath_string
);
490 * kobject_move - move object to another parent
491 * @kobj: object in question.
492 * @new_parent: object's new parent (can be NULL)
495 int kobject_move(struct kobject
*kobj
, struct kobject
*new_parent
)
498 struct kobject
*old_parent
;
499 const char *devpath
= NULL
;
500 char *devpath_string
= NULL
;
503 kobj
= kobject_get(kobj
);
506 new_parent
= kobject_get(new_parent
);
509 new_parent
= kobject_get(&kobj
->kset
->kobj
);
511 /* old object path */
512 devpath
= kobject_get_path(kobj
, GFP_KERNEL
);
517 devpath_string
= kmalloc(strlen(devpath
) + 15, GFP_KERNEL
);
518 if (!devpath_string
) {
522 sprintf(devpath_string
, "DEVPATH_OLD=%s", devpath
);
523 envp
[0] = devpath_string
;
525 error
= sysfs_move_dir(kobj
, new_parent
);
528 old_parent
= kobj
->parent
;
529 kobj
->parent
= new_parent
;
531 kobject_put(old_parent
);
532 kobject_uevent_env(kobj
, KOBJ_MOVE
, envp
);
534 kobject_put(new_parent
);
536 kfree(devpath_string
);
542 * kobject_del - unlink kobject from hierarchy.
546 void kobject_del(struct kobject
* kobj
)
550 sysfs_remove_dir(kobj
);
555 * kobject_unregister - remove object from hierarchy and decrement refcount.
556 * @kobj: object going away.
559 void kobject_unregister(struct kobject
* kobj
)
563 pr_debug("kobject %s: unregistering\n",kobject_name(kobj
));
564 kobject_uevent(kobj
, KOBJ_REMOVE
);
570 * kobject_get - increment refcount for object.
574 struct kobject
* kobject_get(struct kobject
* kobj
)
577 kref_get(&kobj
->kref
);
582 * kobject_cleanup - free kobject resources.
583 * @kobj: object to cleanup
585 static void kobject_cleanup(struct kobject
*kobj
)
587 struct kobj_type
* t
= get_ktype(kobj
);
588 struct kset
* s
= kobj
->kset
;
589 struct kobject
* parent
= kobj
->parent
;
590 const char *name
= kobj
->k_name
;
592 pr_debug("kobject %s: cleaning up\n",kobject_name(kobj
));
593 if (t
&& t
->release
) {
595 /* If we have a release function, we can guess that this was
596 * not a statically allocated kobject, so we should be safe to
605 static void kobject_release(struct kref
*kref
)
607 kobject_cleanup(container_of(kref
, struct kobject
, kref
));
611 * kobject_put - decrement refcount for object.
614 * Decrement the refcount, and if 0, call kobject_cleanup().
616 void kobject_put(struct kobject
* kobj
)
619 kref_put(&kobj
->kref
, kobject_release
);
622 static void dynamic_kobj_release(struct kobject
*kobj
)
624 pr_debug("%s: freeing %s\n", __FUNCTION__
, kobject_name(kobj
));
628 static struct kobj_type dynamic_kobj_ktype
= {
629 .release
= dynamic_kobj_release
,
630 .sysfs_ops
= &kobj_sysfs_ops
,
634 * kobject_create - create a struct kobject dynamically
636 * This function creates a kobject structure dynamically and sets it up
637 * to be a "dynamic" kobject with a default release function set up.
639 * If the kobject was not able to be created, NULL will be returned.
640 * The kobject structure returned from here must be cleaned up with a
641 * call to kobject_put() and not kfree(), as kobject_init_ng() has
642 * already been called on this structure.
644 struct kobject
*kobject_create(void)
646 struct kobject
*kobj
;
648 kobj
= kzalloc(sizeof(*kobj
), GFP_KERNEL
);
652 kobject_init_ng(kobj
, &dynamic_kobj_ktype
);
657 * kobject_create_and_add - create a struct kobject dynamically and register it with sysfs
659 * @name: the name for the kset
660 * @parent: the parent kobject of this kobject, if any.
662 * This function creates a kset structure dynamically and registers it
663 * with sysfs. When you are finished with this structure, call
664 * kobject_unregister() and the structure will be dynamically freed when
665 * it is no longer being used.
667 * If the kobject was not able to be created, NULL will be returned.
669 struct kobject
*kobject_create_and_add(const char *name
, struct kobject
*parent
)
671 struct kobject
*kobj
;
674 kobj
= kobject_create();
678 retval
= kobject_add_ng(kobj
, parent
, "%s", name
);
680 printk(KERN_WARNING
"%s: kobject_add error: %d\n",
681 __FUNCTION__
, retval
);
687 EXPORT_SYMBOL_GPL(kobject_create_and_add
);
690 * kset_init - initialize a kset for use
694 void kset_init(struct kset
* k
)
696 kobject_init(&k
->kobj
);
697 INIT_LIST_HEAD(&k
->list
);
698 spin_lock_init(&k
->list_lock
);
701 /* default kobject attribute operations */
702 static ssize_t
kobj_attr_show(struct kobject
*kobj
, struct attribute
*attr
,
705 struct kobj_attribute
*kattr
;
708 kattr
= container_of(attr
, struct kobj_attribute
, attr
);
710 ret
= kattr
->show(kobj
, kattr
, buf
);
714 static ssize_t
kobj_attr_store(struct kobject
*kobj
, struct attribute
*attr
,
715 const char *buf
, size_t count
)
717 struct kobj_attribute
*kattr
;
720 kattr
= container_of(attr
, struct kobj_attribute
, attr
);
722 ret
= kattr
->store(kobj
, kattr
, buf
, count
);
726 struct sysfs_ops kobj_sysfs_ops
= {
727 .show
= kobj_attr_show
,
728 .store
= kobj_attr_store
,
732 * kset_add - add a kset object to the hierarchy.
736 int kset_add(struct kset
* k
)
738 return kobject_add(&k
->kobj
);
743 * kset_register - initialize and add a kset.
747 int kset_register(struct kset
* k
)
758 kobject_uevent(&k
->kobj
, KOBJ_ADD
);
764 * kset_unregister - remove a kset.
768 void kset_unregister(struct kset
* k
)
772 kobject_unregister(&k
->kobj
);
777 * kset_find_obj - search for object in kset.
778 * @kset: kset we're looking in.
779 * @name: object's name.
781 * Lock kset via @kset->subsys, and iterate over @kset->list,
782 * looking for a matching kobject. If matching object is found
783 * take a reference and return the object.
786 struct kobject
* kset_find_obj(struct kset
* kset
, const char * name
)
788 struct list_head
* entry
;
789 struct kobject
* ret
= NULL
;
791 spin_lock(&kset
->list_lock
);
792 list_for_each(entry
,&kset
->list
) {
793 struct kobject
* k
= to_kobj(entry
);
794 if (kobject_name(k
) && !strcmp(kobject_name(k
),name
)) {
795 ret
= kobject_get(k
);
799 spin_unlock(&kset
->list_lock
);
803 int subsystem_register(struct kset
*s
)
805 return kset_register(s
);
808 void subsystem_unregister(struct kset
*s
)
813 static void kset_release(struct kobject
*kobj
)
815 struct kset
*kset
= container_of(kobj
, struct kset
, kobj
);
816 pr_debug("kset %s: now freed\n", kobject_name(kobj
));
820 static struct kobj_type kset_ktype
= {
821 .sysfs_ops
= &kobj_sysfs_ops
,
822 .release
= kset_release
,
826 * kset_create - create a struct kset dynamically
828 * @name: the name for the kset
829 * @uevent_ops: a struct kset_uevent_ops for the kset
830 * @parent_kobj: the parent kobject of this kset, if any.
832 * This function creates a kset structure dynamically. This structure can
833 * then be registered with the system and show up in sysfs with a call to
834 * kset_register(). When you are finished with this structure, if
835 * kset_register() has been called, call kset_unregister() and the
836 * structure will be dynamically freed when it is no longer being used.
838 * If the kset was not able to be created, NULL will be returned.
840 static struct kset
*kset_create(const char *name
,
841 struct kset_uevent_ops
*uevent_ops
,
842 struct kobject
*parent_kobj
)
846 kset
= kzalloc(sizeof(*kset
), GFP_KERNEL
);
849 kobject_set_name(&kset
->kobj
, name
);
850 kset
->uevent_ops
= uevent_ops
;
851 kset
->kobj
.parent
= parent_kobj
;
854 * The kobject of this kset will have a type of kset_ktype and belong to
855 * no kset itself. That way we can properly free it when it is
856 * finished being used.
858 kset
->kobj
.ktype
= &kset_ktype
;
859 kset
->kobj
.kset
= NULL
;
865 * kset_create_and_add - create a struct kset dynamically and add it to sysfs
867 * @name: the name for the kset
868 * @uevent_ops: a struct kset_uevent_ops for the kset
869 * @parent_kobj: the parent kobject of this kset, if any.
871 * This function creates a kset structure dynamically and registers it
872 * with sysfs. When you are finished with this structure, call
873 * kset_unregister() and the structure will be dynamically freed when it
874 * is no longer being used.
876 * If the kset was not able to be created, NULL will be returned.
878 struct kset
*kset_create_and_add(const char *name
,
879 struct kset_uevent_ops
*uevent_ops
,
880 struct kobject
*parent_kobj
)
885 kset
= kset_create(name
, uevent_ops
, parent_kobj
);
888 error
= kset_register(kset
);
895 EXPORT_SYMBOL_GPL(kset_create_and_add
);
897 EXPORT_SYMBOL(kobject_init
);
898 EXPORT_SYMBOL(kobject_register
);
899 EXPORT_SYMBOL(kobject_unregister
);
900 EXPORT_SYMBOL(kobject_get
);
901 EXPORT_SYMBOL(kobject_put
);
902 EXPORT_SYMBOL(kobject_add
);
903 EXPORT_SYMBOL(kobject_del
);
905 EXPORT_SYMBOL(kset_register
);
906 EXPORT_SYMBOL(kset_unregister
);
908 EXPORT_SYMBOL(subsystem_register
);
909 EXPORT_SYMBOL(subsystem_unregister
);