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 list_add_tail(&kobj
->entry
,&kobj
->kset
->list
);
193 spin_unlock(&kobj
->kset
->list_lock
);
194 kobj
->parent
= parent
;
197 error
= create_dir(kobj
);
199 /* unlink does the kobject_put() for us */
203 /* be noisy on error issues */
204 if (error
== -EEXIST
)
205 printk(KERN_ERR
"kobject_add failed for %s with "
206 "-EEXIST, don't try to register things with "
207 "the same name in the same directory.\n",
210 printk(KERN_ERR
"kobject_add failed for %s (%d)\n",
211 kobject_name(kobj
), error
);
219 * kobject_register - initialize and add an object.
220 * @kobj: object in question.
223 int kobject_register(struct kobject
* kobj
)
228 error
= kobject_add(kobj
);
230 kobject_uevent(kobj
, KOBJ_ADD
);
236 * kobject_set_name_vargs - Set the name of an kobject
237 * @kobj: struct kobject to set the name of
238 * @fmt: format string used to build the name
239 * @vargs: vargs to format the string.
241 static int kobject_set_name_vargs(struct kobject
*kobj
, const char *fmt
,
248 name
= kvasprintf(GFP_KERNEL
, fmt
, vargs
);
254 /* Free the old name, if necessary. */
257 /* Now, set the new name */
264 * kobject_set_name - Set the name of a kobject
265 * @kobj: struct kobject to set the name of
266 * @fmt: format string used to build the name
268 * This sets the name of the kobject. If you have already added the
269 * kobject to the system, you must call kobject_rename() in order to
270 * change the name of the kobject.
272 int kobject_set_name(struct kobject
*kobj
, const char *fmt
, ...)
278 retval
= kobject_set_name_vargs(kobj
, fmt
, args
);
283 EXPORT_SYMBOL(kobject_set_name
);
286 * kobject_init_ng - initialize a kobject structure
287 * @kobj: pointer to the kobject to initialize
288 * @ktype: pointer to the ktype for this kobject.
290 * This function will properly initialize a kobject such that it can then
291 * be passed to the kobject_add() call.
293 * After this function is called, the kobject MUST be cleaned up by a call
294 * to kobject_put(), not by a call to kfree directly to ensure that all of
295 * the memory is cleaned up properly.
297 void kobject_init_ng(struct kobject
*kobj
, struct kobj_type
*ktype
)
302 err_str
= "invalid kobject pointer!";
306 err_str
= "must have a ktype to be initialized properly!\n";
309 if (atomic_read(&kobj
->kref
.refcount
)) {
310 /* do not error out as sometimes we can recover */
311 printk(KERN_ERR
"kobject: reference count is already set, "
312 "something is seriously wrong.\n");
316 kref_init(&kobj
->kref
);
317 INIT_LIST_HEAD(&kobj
->entry
);
322 printk(KERN_ERR
"kobject: %s\n", err_str
);
325 EXPORT_SYMBOL(kobject_init_ng
);
327 static int kobject_add_varg(struct kobject
*kobj
, struct kobject
*parent
,
328 const char *fmt
, va_list vargs
)
334 retval
= kobject_set_name_vargs(kobj
, fmt
, aq
);
337 printk(KERN_ERR
"kobject: can not set name properly!\n");
340 kobj
->parent
= parent
;
341 return kobject_add(kobj
);
345 * kobject_add_ng - the main kobject add function
346 * @kobj: the kobject to add
347 * @parent: pointer to the parent of the kobject.
348 * @fmt: format to name the kobject with.
350 * The kobject name is set and added to the kobject hierarchy in this
353 * If @parent is set, then the parent of the @kobj will be set to it.
354 * If @parent is NULL, then the parent of the @kobj will be set to the
355 * kobject associted with the kset assigned to this kobject. If no kset
356 * is assigned to the kobject, then the kobject will be located in the
357 * root of the sysfs tree.
359 * If this function returns an error, kobject_put() must be called to
360 * properly clean up the memory associated with the object.
362 * If the function is successful, the only way to properly clean up the
363 * memory is with a call to kobject_del(), in which case, a call to
364 * kobject_put() is not necessary (kobject_del() does the final
365 * kobject_put() to call the release function in the ktype's release
368 * Under no instance should the kobject that is passed to this function
369 * be directly freed with a call to kfree(), that can leak memory.
371 * Note, no uevent will be created with this call, the caller should set
372 * up all of the necessary sysfs files for the object and then call
373 * kobject_uevent() with the UEVENT_ADD parameter to ensure that
374 * userspace is properly notified of this kobject's creation.
376 int kobject_add_ng(struct kobject
*kobj
, struct kobject
*parent
,
377 const char *fmt
, ...)
386 retval
= kobject_add_varg(kobj
, parent
, fmt
, args
);
391 EXPORT_SYMBOL(kobject_add_ng
);
394 * kobject_init_and_add - initialize a kobject structure and add it to the kobject hierarchy
395 * @kobj: pointer to the kobject to initialize
396 * @ktype: pointer to the ktype for this kobject.
397 * @parent: pointer to the parent of this kobject.
398 * @fmt: the name of the kobject.
400 * This function combines the call to kobject_init_ng() and
401 * kobject_add_ng(). The same type of error handling after a call to
402 * kobject_add_ng() and kobject lifetime rules are the same here.
404 int kobject_init_and_add(struct kobject
*kobj
, struct kobj_type
*ktype
,
405 struct kobject
*parent
, const char *fmt
, ...)
410 kobject_init_ng(kobj
, ktype
);
413 retval
= kobject_add_varg(kobj
, parent
, fmt
, args
);
418 EXPORT_SYMBOL_GPL(kobject_init_and_add
);
421 * kobject_rename - change the name of an object
422 * @kobj: object in question.
423 * @new_name: object's new name
426 int kobject_rename(struct kobject
* kobj
, const char *new_name
)
429 const char *devpath
= NULL
;
430 char *devpath_string
= NULL
;
433 kobj
= kobject_get(kobj
);
439 /* see if this name is already in use */
441 struct kobject
*temp_kobj
;
442 temp_kobj
= kset_find_obj(kobj
->kset
, new_name
);
444 printk(KERN_WARNING
"kobject '%s' cannot be renamed "
445 "to '%s' as '%s' is already in existence.\n",
446 kobject_name(kobj
), new_name
, new_name
);
447 kobject_put(temp_kobj
);
452 devpath
= kobject_get_path(kobj
, GFP_KERNEL
);
457 devpath_string
= kmalloc(strlen(devpath
) + 15, GFP_KERNEL
);
458 if (!devpath_string
) {
462 sprintf(devpath_string
, "DEVPATH_OLD=%s", devpath
);
463 envp
[0] = devpath_string
;
466 error
= sysfs_rename_dir(kobj
, new_name
);
468 /* This function is mostly/only used for network interface.
469 * Some hotplug package track interfaces by their name and
470 * therefore want to know when the name is changed by the user. */
472 kobject_uevent_env(kobj
, KOBJ_MOVE
, envp
);
475 kfree(devpath_string
);
483 * kobject_move - move object to another parent
484 * @kobj: object in question.
485 * @new_parent: object's new parent (can be NULL)
488 int kobject_move(struct kobject
*kobj
, struct kobject
*new_parent
)
491 struct kobject
*old_parent
;
492 const char *devpath
= NULL
;
493 char *devpath_string
= NULL
;
496 kobj
= kobject_get(kobj
);
499 new_parent
= kobject_get(new_parent
);
502 new_parent
= kobject_get(&kobj
->kset
->kobj
);
504 /* old object path */
505 devpath
= kobject_get_path(kobj
, GFP_KERNEL
);
510 devpath_string
= kmalloc(strlen(devpath
) + 15, GFP_KERNEL
);
511 if (!devpath_string
) {
515 sprintf(devpath_string
, "DEVPATH_OLD=%s", devpath
);
516 envp
[0] = devpath_string
;
518 error
= sysfs_move_dir(kobj
, new_parent
);
521 old_parent
= kobj
->parent
;
522 kobj
->parent
= new_parent
;
524 kobject_put(old_parent
);
525 kobject_uevent_env(kobj
, KOBJ_MOVE
, envp
);
527 kobject_put(new_parent
);
529 kfree(devpath_string
);
535 * kobject_del - unlink kobject from hierarchy.
539 void kobject_del(struct kobject
* kobj
)
543 sysfs_remove_dir(kobj
);
548 * kobject_unregister - remove object from hierarchy and decrement refcount.
549 * @kobj: object going away.
552 void kobject_unregister(struct kobject
* kobj
)
556 pr_debug("kobject %s: unregistering\n",kobject_name(kobj
));
557 kobject_uevent(kobj
, KOBJ_REMOVE
);
563 * kobject_get - increment refcount for object.
567 struct kobject
* kobject_get(struct kobject
* kobj
)
570 kref_get(&kobj
->kref
);
575 * kobject_cleanup - free kobject resources.
576 * @kobj: object to cleanup
578 static void kobject_cleanup(struct kobject
*kobj
)
580 struct kobj_type
* t
= get_ktype(kobj
);
581 struct kset
* s
= kobj
->kset
;
582 struct kobject
* parent
= kobj
->parent
;
583 const char *name
= kobj
->k_name
;
585 pr_debug("kobject %s: cleaning up\n",kobject_name(kobj
));
586 if (t
&& t
->release
) {
588 /* If we have a release function, we can guess that this was
589 * not a statically allocated kobject, so we should be safe to
598 static void kobject_release(struct kref
*kref
)
600 kobject_cleanup(container_of(kref
, struct kobject
, kref
));
604 * kobject_put - decrement refcount for object.
607 * Decrement the refcount, and if 0, call kobject_cleanup().
609 void kobject_put(struct kobject
* kobj
)
612 kref_put(&kobj
->kref
, kobject_release
);
616 static void dir_release(struct kobject
*kobj
)
621 static struct kobj_type dir_ktype
= {
622 .release
= dir_release
,
624 .default_attrs
= NULL
,
628 * kobject_kset_add_dir - add sub directory of object.
629 * @kset: kset the directory is belongs to.
630 * @parent: object in which a directory is created.
631 * @name: directory name.
633 * Add a plain directory object as child of given object.
635 struct kobject
*kobject_kset_add_dir(struct kset
*kset
,
636 struct kobject
*parent
, const char *name
)
644 k
= kzalloc(sizeof(*k
), GFP_KERNEL
);
650 k
->ktype
= &dir_ktype
;
651 kobject_set_name(k
, name
);
652 ret
= kobject_register(k
);
654 printk(KERN_WARNING
"%s: kobject_register error: %d\n",
664 * kobject_add_dir - add sub directory of object.
665 * @parent: object in which a directory is created.
666 * @name: directory name.
668 * Add a plain directory object as child of given object.
670 struct kobject
*kobject_add_dir(struct kobject
*parent
, const char *name
)
672 return kobject_kset_add_dir(NULL
, parent
, name
);
676 * kset_init - initialize a kset for use
680 void kset_init(struct kset
* k
)
682 kobject_init(&k
->kobj
);
683 INIT_LIST_HEAD(&k
->list
);
684 spin_lock_init(&k
->list_lock
);
689 * kset_add - add a kset object to the hierarchy.
693 int kset_add(struct kset
* k
)
695 return kobject_add(&k
->kobj
);
700 * kset_register - initialize and add a kset.
704 int kset_register(struct kset
* k
)
715 kobject_uevent(&k
->kobj
, KOBJ_ADD
);
721 * kset_unregister - remove a kset.
725 void kset_unregister(struct kset
* k
)
729 kobject_unregister(&k
->kobj
);
734 * kset_find_obj - search for object in kset.
735 * @kset: kset we're looking in.
736 * @name: object's name.
738 * Lock kset via @kset->subsys, and iterate over @kset->list,
739 * looking for a matching kobject. If matching object is found
740 * take a reference and return the object.
743 struct kobject
* kset_find_obj(struct kset
* kset
, const char * name
)
745 struct list_head
* entry
;
746 struct kobject
* ret
= NULL
;
748 spin_lock(&kset
->list_lock
);
749 list_for_each(entry
,&kset
->list
) {
750 struct kobject
* k
= to_kobj(entry
);
751 if (kobject_name(k
) && !strcmp(kobject_name(k
),name
)) {
752 ret
= kobject_get(k
);
756 spin_unlock(&kset
->list_lock
);
760 int subsystem_register(struct kset
*s
)
762 return kset_register(s
);
765 void subsystem_unregister(struct kset
*s
)
771 * subsystem_create_file - export sysfs attribute file.
773 * @a: subsystem attribute descriptor.
776 int subsys_create_file(struct kset
*s
, struct subsys_attribute
*a
)
784 error
= sysfs_create_file(&s
->kobj
, &a
->attr
);
790 EXPORT_SYMBOL(kobject_init
);
791 EXPORT_SYMBOL(kobject_register
);
792 EXPORT_SYMBOL(kobject_unregister
);
793 EXPORT_SYMBOL(kobject_get
);
794 EXPORT_SYMBOL(kobject_put
);
795 EXPORT_SYMBOL(kobject_add
);
796 EXPORT_SYMBOL(kobject_del
);
798 EXPORT_SYMBOL(kset_register
);
799 EXPORT_SYMBOL(kset_unregister
);
801 EXPORT_SYMBOL(subsystem_register
);
802 EXPORT_SYMBOL(subsystem_unregister
);
803 EXPORT_SYMBOL(subsys_create_file
);
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