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git.proxmox.com Git - mirror_ubuntu-bionic-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>
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_rename - change the name of an object
287 * @kobj: object in question.
288 * @new_name: object's new name
291 int kobject_rename(struct kobject
* kobj
, const char *new_name
)
294 const char *devpath
= NULL
;
295 char *devpath_string
= NULL
;
298 kobj
= kobject_get(kobj
);
304 /* see if this name is already in use */
306 struct kobject
*temp_kobj
;
307 temp_kobj
= kset_find_obj(kobj
->kset
, new_name
);
309 printk(KERN_WARNING
"kobject '%s' cannot be renamed "
310 "to '%s' as '%s' is already in existence.\n",
311 kobject_name(kobj
), new_name
, new_name
);
312 kobject_put(temp_kobj
);
317 devpath
= kobject_get_path(kobj
, GFP_KERNEL
);
322 devpath_string
= kmalloc(strlen(devpath
) + 15, GFP_KERNEL
);
323 if (!devpath_string
) {
327 sprintf(devpath_string
, "DEVPATH_OLD=%s", devpath
);
328 envp
[0] = devpath_string
;
331 error
= sysfs_rename_dir(kobj
, new_name
);
333 /* This function is mostly/only used for network interface.
334 * Some hotplug package track interfaces by their name and
335 * therefore want to know when the name is changed by the user. */
337 kobject_uevent_env(kobj
, KOBJ_MOVE
, envp
);
340 kfree(devpath_string
);
348 * kobject_move - move object to another parent
349 * @kobj: object in question.
350 * @new_parent: object's new parent (can be NULL)
353 int kobject_move(struct kobject
*kobj
, struct kobject
*new_parent
)
356 struct kobject
*old_parent
;
357 const char *devpath
= NULL
;
358 char *devpath_string
= NULL
;
361 kobj
= kobject_get(kobj
);
364 new_parent
= kobject_get(new_parent
);
367 new_parent
= kobject_get(&kobj
->kset
->kobj
);
369 /* old object path */
370 devpath
= kobject_get_path(kobj
, GFP_KERNEL
);
375 devpath_string
= kmalloc(strlen(devpath
) + 15, GFP_KERNEL
);
376 if (!devpath_string
) {
380 sprintf(devpath_string
, "DEVPATH_OLD=%s", devpath
);
381 envp
[0] = devpath_string
;
383 error
= sysfs_move_dir(kobj
, new_parent
);
386 old_parent
= kobj
->parent
;
387 kobj
->parent
= new_parent
;
389 kobject_put(old_parent
);
390 kobject_uevent_env(kobj
, KOBJ_MOVE
, envp
);
392 kobject_put(new_parent
);
394 kfree(devpath_string
);
400 * kobject_del - unlink kobject from hierarchy.
404 void kobject_del(struct kobject
* kobj
)
408 sysfs_remove_dir(kobj
);
413 * kobject_unregister - remove object from hierarchy and decrement refcount.
414 * @kobj: object going away.
417 void kobject_unregister(struct kobject
* kobj
)
421 pr_debug("kobject %s: unregistering\n",kobject_name(kobj
));
422 kobject_uevent(kobj
, KOBJ_REMOVE
);
428 * kobject_get - increment refcount for object.
432 struct kobject
* kobject_get(struct kobject
* kobj
)
435 kref_get(&kobj
->kref
);
440 * kobject_cleanup - free kobject resources.
441 * @kobj: object to cleanup
443 static void kobject_cleanup(struct kobject
*kobj
)
445 struct kobj_type
* t
= get_ktype(kobj
);
446 struct kset
* s
= kobj
->kset
;
447 struct kobject
* parent
= kobj
->parent
;
448 const char *name
= kobj
->k_name
;
450 pr_debug("kobject %s: cleaning up\n",kobject_name(kobj
));
451 if (t
&& t
->release
) {
453 /* If we have a release function, we can guess that this was
454 * not a statically allocated kobject, so we should be safe to
463 static void kobject_release(struct kref
*kref
)
465 kobject_cleanup(container_of(kref
, struct kobject
, kref
));
469 * kobject_put - decrement refcount for object.
472 * Decrement the refcount, and if 0, call kobject_cleanup().
474 void kobject_put(struct kobject
* kobj
)
477 kref_put(&kobj
->kref
, kobject_release
);
481 static void dir_release(struct kobject
*kobj
)
486 static struct kobj_type dir_ktype
= {
487 .release
= dir_release
,
489 .default_attrs
= NULL
,
493 * kobject_kset_add_dir - add sub directory of object.
494 * @kset: kset the directory is belongs to.
495 * @parent: object in which a directory is created.
496 * @name: directory name.
498 * Add a plain directory object as child of given object.
500 struct kobject
*kobject_kset_add_dir(struct kset
*kset
,
501 struct kobject
*parent
, const char *name
)
509 k
= kzalloc(sizeof(*k
), GFP_KERNEL
);
515 k
->ktype
= &dir_ktype
;
516 kobject_set_name(k
, name
);
517 ret
= kobject_register(k
);
519 printk(KERN_WARNING
"%s: kobject_register error: %d\n",
529 * kobject_add_dir - add sub directory of object.
530 * @parent: object in which a directory is created.
531 * @name: directory name.
533 * Add a plain directory object as child of given object.
535 struct kobject
*kobject_add_dir(struct kobject
*parent
, const char *name
)
537 return kobject_kset_add_dir(NULL
, parent
, name
);
541 * kset_init - initialize a kset for use
545 void kset_init(struct kset
* k
)
547 kobject_init(&k
->kobj
);
548 INIT_LIST_HEAD(&k
->list
);
549 spin_lock_init(&k
->list_lock
);
554 * kset_add - add a kset object to the hierarchy.
558 int kset_add(struct kset
* k
)
560 return kobject_add(&k
->kobj
);
565 * kset_register - initialize and add a kset.
569 int kset_register(struct kset
* k
)
580 kobject_uevent(&k
->kobj
, KOBJ_ADD
);
586 * kset_unregister - remove a kset.
590 void kset_unregister(struct kset
* k
)
594 kobject_unregister(&k
->kobj
);
599 * kset_find_obj - search for object in kset.
600 * @kset: kset we're looking in.
601 * @name: object's name.
603 * Lock kset via @kset->subsys, and iterate over @kset->list,
604 * looking for a matching kobject. If matching object is found
605 * take a reference and return the object.
608 struct kobject
* kset_find_obj(struct kset
* kset
, const char * name
)
610 struct list_head
* entry
;
611 struct kobject
* ret
= NULL
;
613 spin_lock(&kset
->list_lock
);
614 list_for_each(entry
,&kset
->list
) {
615 struct kobject
* k
= to_kobj(entry
);
616 if (kobject_name(k
) && !strcmp(kobject_name(k
),name
)) {
617 ret
= kobject_get(k
);
621 spin_unlock(&kset
->list_lock
);
625 int subsystem_register(struct kset
*s
)
627 return kset_register(s
);
630 void subsystem_unregister(struct kset
*s
)
636 * subsystem_create_file - export sysfs attribute file.
638 * @a: subsystem attribute descriptor.
641 int subsys_create_file(struct kset
*s
, struct subsys_attribute
*a
)
649 error
= sysfs_create_file(&s
->kobj
, &a
->attr
);
655 EXPORT_SYMBOL(kobject_init
);
656 EXPORT_SYMBOL(kobject_register
);
657 EXPORT_SYMBOL(kobject_unregister
);
658 EXPORT_SYMBOL(kobject_get
);
659 EXPORT_SYMBOL(kobject_put
);
660 EXPORT_SYMBOL(kobject_add
);
661 EXPORT_SYMBOL(kobject_del
);
663 EXPORT_SYMBOL(kset_register
);
664 EXPORT_SYMBOL(kset_unregister
);
666 EXPORT_SYMBOL(subsystem_register
);
667 EXPORT_SYMBOL(subsystem_unregister
);
668 EXPORT_SYMBOL(subsys_create_file
);