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git.proxmox.com Git - mirror_ubuntu-zesty-kernel.git/blob - lib/kobject.c
2 * kobject.c - library routines for handling generic kernel objects
4 * Copyright (c) 2002-2003 Patrick Mochel <mochel@osdl.org>
6 * This file is released under the GPLv2.
9 * Please see the file Documentation/kobject.txt for critical information
10 * about using the kobject interface.
13 #include <linux/kobject.h>
14 #include <linux/string.h>
15 #include <linux/module.h>
16 #include <linux/stat.h>
17 #include <linux/slab.h>
20 * populate_dir - populate directory with attributes.
21 * @kobj: object we're working on.
23 * Most subsystems have a set of default attributes that
24 * are associated with an object that registers with them.
25 * This is a helper called during object registration that
26 * loops through the default attributes of the subsystem
27 * and creates attributes files for them in sysfs.
31 static int populate_dir(struct kobject
* kobj
)
33 struct kobj_type
* t
= get_ktype(kobj
);
34 struct attribute
* attr
;
38 if (t
&& t
->default_attrs
) {
39 for (i
= 0; (attr
= t
->default_attrs
[i
]) != NULL
; i
++) {
40 if ((error
= sysfs_create_file(kobj
,attr
)))
47 static int create_dir(struct kobject
* kobj
, struct dentry
*shadow_parent
)
50 if (kobject_name(kobj
)) {
51 error
= sysfs_create_dir(kobj
, shadow_parent
);
53 if ((error
= populate_dir(kobj
)))
54 sysfs_remove_dir(kobj
);
60 static inline struct kobject
* to_kobj(struct list_head
* entry
)
62 return container_of(entry
,struct kobject
,entry
);
65 static int get_kobj_path_length(struct kobject
*kobj
)
68 struct kobject
* parent
= kobj
;
70 /* walk up the ancestors until we hit the one pointing to the
72 * Add 1 to strlen for leading '/' of each level.
75 if (kobject_name(parent
) == NULL
)
77 length
+= strlen(kobject_name(parent
)) + 1;
78 parent
= parent
->parent
;
83 static void fill_kobj_path(struct kobject
*kobj
, char *path
, int length
)
85 struct kobject
* parent
;
88 for (parent
= kobj
; parent
; parent
= parent
->parent
) {
89 int cur
= strlen(kobject_name(parent
));
90 /* back up enough to print this name with '/' */
92 strncpy (path
+ length
, kobject_name(parent
), cur
);
93 *(path
+ --length
) = '/';
96 pr_debug("%s: path = '%s'\n",__FUNCTION__
,path
);
100 * kobject_get_path - generate and return the path associated with a given kobj and kset pair.
102 * @kobj: kobject in question, with which to build the path
103 * @gfp_mask: the allocation type used to allocate the path
105 * The result must be freed by the caller with kfree().
107 char *kobject_get_path(struct kobject
*kobj
, gfp_t gfp_mask
)
112 len
= get_kobj_path_length(kobj
);
115 path
= kzalloc(len
, gfp_mask
);
118 fill_kobj_path(kobj
, path
, len
);
122 EXPORT_SYMBOL_GPL(kobject_get_path
);
125 * kobject_init - initialize object.
126 * @kobj: object in question.
128 void kobject_init(struct kobject
* kobj
)
132 kref_init(&kobj
->kref
);
133 INIT_LIST_HEAD(&kobj
->entry
);
134 init_waitqueue_head(&kobj
->poll
);
135 kobj
->kset
= kset_get(kobj
->kset
);
140 * unlink - remove kobject from kset list.
143 * Remove the kobject from the kset list and decrement
144 * its parent's refcount.
145 * This is separated out, so we can use it in both
146 * kobject_del() and kobject_add() on error.
149 static void unlink(struct kobject
* kobj
)
152 spin_lock(&kobj
->kset
->list_lock
);
153 list_del_init(&kobj
->entry
);
154 spin_unlock(&kobj
->kset
->list_lock
);
160 * kobject_shadow_add - add an object to the hierarchy.
162 * @shadow_parent: sysfs directory to add to.
165 int kobject_shadow_add(struct kobject
* kobj
, struct dentry
*shadow_parent
)
168 struct kobject
* parent
;
170 if (!(kobj
= kobject_get(kobj
)))
173 kobj
->k_name
= kobj
->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
? kobj
->kset
->kobj
.name
: "<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
, shadow_parent
);
199 /* unlink does the kobject_put() for us */
203 /* be noisy on error issues */
204 if (error
== -EEXIST
)
205 printk("kobject_add failed for %s with -EEXIST, "
206 "don't try to register things with the "
207 "same name in the same directory.\n",
210 printk("kobject_add failed for %s (%d)\n",
211 kobject_name(kobj
), error
);
219 * kobject_add - add an object to the hierarchy.
222 int kobject_add(struct kobject
* kobj
)
224 return kobject_shadow_add(kobj
, NULL
);
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
);
247 * kobject_set_name - Set the name of an object
249 * @fmt: format string used to build the name
251 * If strlen(name) >= KOBJ_NAME_LEN, then use a dynamically allocated
252 * string that @kobj->k_name points to. Otherwise, use the static
255 int kobject_set_name(struct kobject
* kobj
, const char * fmt
, ...)
258 int limit
= KOBJ_NAME_LEN
;
264 * First, try the static array
267 need
= vsnprintf(kobj
->name
,limit
,fmt
,args
);
273 * Need more space? Allocate it and try again
276 name
= kmalloc(limit
,GFP_KERNEL
);
282 need
= vsnprintf(name
,limit
,fmt
,args
);
285 /* Still? Give up. */
293 /* Free the old name, if necessary. */
294 if (kobj
->k_name
&& kobj
->k_name
!= kobj
->name
)
297 /* Now, set the new name */
303 EXPORT_SYMBOL(kobject_set_name
);
307 * kobject_rename - change the name of an object
308 * @kobj: object in question.
309 * @new_name: object's new name
312 int kobject_rename(struct kobject
* kobj
, const char *new_name
)
315 const char *devpath
= NULL
;
316 char *devpath_string
= NULL
;
319 kobj
= kobject_get(kobj
);
325 devpath
= kobject_get_path(kobj
, GFP_KERNEL
);
330 devpath_string
= kmalloc(strlen(devpath
) + 15, GFP_KERNEL
);
331 if (!devpath_string
) {
335 sprintf(devpath_string
, "DEVPATH_OLD=%s", devpath
);
336 envp
[0] = devpath_string
;
338 /* Note : if we want to send the new name alone, not the full path,
339 * we could probably use kobject_name(kobj); */
341 error
= sysfs_rename_dir(kobj
, kobj
->parent
->dentry
, new_name
);
343 /* This function is mostly/only used for network interface.
344 * Some hotplug package track interfaces by their name and
345 * therefore want to know when the name is changed by the user. */
347 kobject_uevent_env(kobj
, KOBJ_MOVE
, envp
);
350 kfree(devpath_string
);
358 * kobject_rename - change the name of an object
359 * @kobj: object in question.
360 * @new_parent: object's new parent
361 * @new_name: object's new name
364 int kobject_shadow_rename(struct kobject
* kobj
, struct dentry
*new_parent
,
365 const char *new_name
)
369 kobj
= kobject_get(kobj
);
372 error
= sysfs_rename_dir(kobj
, new_parent
, new_name
);
379 * kobject_move - move object to another parent
380 * @kobj: object in question.
381 * @new_parent: object's new parent (can be NULL)
384 int kobject_move(struct kobject
*kobj
, struct kobject
*new_parent
)
387 struct kobject
*old_parent
;
388 const char *devpath
= NULL
;
389 char *devpath_string
= NULL
;
392 kobj
= kobject_get(kobj
);
395 new_parent
= kobject_get(new_parent
);
398 new_parent
= kobject_get(&kobj
->kset
->kobj
);
400 /* old object path */
401 devpath
= kobject_get_path(kobj
, GFP_KERNEL
);
406 devpath_string
= kmalloc(strlen(devpath
) + 15, GFP_KERNEL
);
407 if (!devpath_string
) {
411 sprintf(devpath_string
, "DEVPATH_OLD=%s", devpath
);
412 envp
[0] = devpath_string
;
414 error
= sysfs_move_dir(kobj
, new_parent
);
417 old_parent
= kobj
->parent
;
418 kobj
->parent
= new_parent
;
420 kobject_put(old_parent
);
421 kobject_uevent_env(kobj
, KOBJ_MOVE
, envp
);
423 kobject_put(new_parent
);
425 kfree(devpath_string
);
431 * kobject_del - unlink kobject from hierarchy.
435 void kobject_del(struct kobject
* kobj
)
439 sysfs_remove_dir(kobj
);
444 * kobject_unregister - remove object from hierarchy and decrement refcount.
445 * @kobj: object going away.
448 void kobject_unregister(struct kobject
* kobj
)
452 pr_debug("kobject %s: unregistering\n",kobject_name(kobj
));
453 kobject_uevent(kobj
, KOBJ_REMOVE
);
459 * kobject_get - increment refcount for object.
463 struct kobject
* kobject_get(struct kobject
* kobj
)
466 kref_get(&kobj
->kref
);
471 * kobject_cleanup - free kobject resources.
475 void kobject_cleanup(struct kobject
* kobj
)
477 struct kobj_type
* t
= get_ktype(kobj
);
478 struct kset
* s
= kobj
->kset
;
479 struct kobject
* parent
= kobj
->parent
;
481 pr_debug("kobject %s: cleaning up\n",kobject_name(kobj
));
482 if (kobj
->k_name
!= kobj
->name
)
492 static void kobject_release(struct kref
*kref
)
494 kobject_cleanup(container_of(kref
, struct kobject
, kref
));
498 * kobject_put - decrement refcount for object.
501 * Decrement the refcount, and if 0, call kobject_cleanup().
503 void kobject_put(struct kobject
* kobj
)
506 kref_put(&kobj
->kref
, kobject_release
);
510 static void dir_release(struct kobject
*kobj
)
515 static struct kobj_type dir_ktype
= {
516 .release
= dir_release
,
518 .default_attrs
= NULL
,
522 * kobject_kset_add_dir - add sub directory of object.
523 * @kset: kset the directory is belongs to.
524 * @parent: object in which a directory is created.
525 * @name: directory name.
527 * Add a plain directory object as child of given object.
529 struct kobject
*kobject_kset_add_dir(struct kset
*kset
,
530 struct kobject
*parent
, const char *name
)
538 k
= kzalloc(sizeof(*k
), GFP_KERNEL
);
544 k
->ktype
= &dir_ktype
;
545 kobject_set_name(k
, name
);
546 ret
= kobject_register(k
);
548 printk(KERN_WARNING
"%s: kobject_register error: %d\n",
558 * kobject_add_dir - add sub directory of object.
559 * @parent: object in which a directory is created.
560 * @name: directory name.
562 * Add a plain directory object as child of given object.
564 struct kobject
*kobject_add_dir(struct kobject
*parent
, const char *name
)
566 return kobject_kset_add_dir(NULL
, parent
, name
);
570 * kset_init - initialize a kset for use
574 void kset_init(struct kset
* k
)
576 kobject_init(&k
->kobj
);
577 INIT_LIST_HEAD(&k
->list
);
578 spin_lock_init(&k
->list_lock
);
583 * kset_add - add a kset object to the hierarchy.
587 int kset_add(struct kset
* k
)
589 return kobject_add(&k
->kobj
);
594 * kset_register - initialize and add a kset.
598 int kset_register(struct kset
* k
)
608 * kset_unregister - remove a kset.
612 void kset_unregister(struct kset
* k
)
616 kobject_unregister(&k
->kobj
);
621 * kset_find_obj - search for object in kset.
622 * @kset: kset we're looking in.
623 * @name: object's name.
625 * Lock kset via @kset->subsys, and iterate over @kset->list,
626 * looking for a matching kobject. If matching object is found
627 * take a reference and return the object.
630 struct kobject
* kset_find_obj(struct kset
* kset
, const char * name
)
632 struct list_head
* entry
;
633 struct kobject
* ret
= NULL
;
635 spin_lock(&kset
->list_lock
);
636 list_for_each(entry
,&kset
->list
) {
637 struct kobject
* k
= to_kobj(entry
);
638 if (kobject_name(k
) && !strcmp(kobject_name(k
),name
)) {
639 ret
= kobject_get(k
);
643 spin_unlock(&kset
->list_lock
);
647 void subsystem_init(struct kset
*s
)
652 int subsystem_register(struct kset
*s
)
654 return kset_register(s
);
657 void subsystem_unregister(struct kset
*s
)
663 * subsystem_create_file - export sysfs attribute file.
665 * @a: subsystem attribute descriptor.
668 int subsys_create_file(struct kset
*s
, struct subsys_attribute
*a
)
676 error
= sysfs_create_file(&s
->kobj
, &a
->attr
);
682 EXPORT_SYMBOL(kobject_init
);
683 EXPORT_SYMBOL(kobject_register
);
684 EXPORT_SYMBOL(kobject_unregister
);
685 EXPORT_SYMBOL(kobject_get
);
686 EXPORT_SYMBOL(kobject_put
);
687 EXPORT_SYMBOL(kobject_add
);
688 EXPORT_SYMBOL(kobject_del
);
690 EXPORT_SYMBOL(kset_register
);
691 EXPORT_SYMBOL(kset_unregister
);
693 EXPORT_SYMBOL(subsystem_register
);
694 EXPORT_SYMBOL(subsystem_unregister
);
695 EXPORT_SYMBOL(subsys_create_file
);