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.
15 #include <linux/kobject.h>
16 #include <linux/string.h>
17 #include <linux/module.h>
18 #include <linux/stat.h>
21 * populate_dir - populate directory with attributes.
22 * @kobj: object we're working on.
24 * Most subsystems have a set of default attributes that
25 * are associated with an object that registers with them.
26 * This is a helper called during object registration that
27 * loops through the default attributes of the subsystem
28 * and creates attributes files for them in sysfs.
32 static int populate_dir(struct kobject
* kobj
)
34 struct kobj_type
* t
= get_ktype(kobj
);
35 struct attribute
* attr
;
39 if (t
&& t
->default_attrs
) {
40 for (i
= 0; (attr
= t
->default_attrs
[i
]) != NULL
; i
++) {
41 if ((error
= sysfs_create_file(kobj
,attr
)))
48 static int create_dir(struct kobject
* kobj
)
51 if (kobject_name(kobj
)) {
52 error
= sysfs_create_dir(kobj
);
54 if ((error
= populate_dir(kobj
)))
55 sysfs_remove_dir(kobj
);
61 static inline struct kobject
* to_kobj(struct list_head
* entry
)
63 return container_of(entry
,struct kobject
,entry
);
66 static int get_kobj_path_length(struct kobject
*kobj
)
69 struct kobject
* parent
= kobj
;
71 /* walk up the ancestors until we hit the one pointing to the
73 * Add 1 to strlen for leading '/' of each level.
76 length
+= strlen(kobject_name(parent
)) + 1;
77 parent
= parent
->parent
;
82 static void fill_kobj_path(struct kobject
*kobj
, char *path
, int length
)
84 struct kobject
* parent
;
87 for (parent
= kobj
; parent
; parent
= parent
->parent
) {
88 int cur
= strlen(kobject_name(parent
));
89 /* back up enough to print this name with '/' */
91 strncpy (path
+ length
, kobject_name(parent
), cur
);
92 *(path
+ --length
) = '/';
95 pr_debug("%s: path = '%s'\n",__FUNCTION__
,path
);
99 * kobject_get_path - generate and return the path associated with a given kobj
100 * and kset pair. The result must be freed by the caller with kfree().
102 * @kobj: kobject in question, with which to build the path
103 * @gfp_mask: the allocation type used to allocate the path
105 char *kobject_get_path(struct kobject
*kobj
, int gfp_mask
)
110 len
= get_kobj_path_length(kobj
);
111 path
= kmalloc(len
, gfp_mask
);
114 memset(path
, 0x00, len
);
115 fill_kobj_path(kobj
, path
, len
);
121 * kobject_init - initialize object.
122 * @kobj: object in question.
124 void kobject_init(struct kobject
* kobj
)
126 kref_init(&kobj
->kref
);
127 INIT_LIST_HEAD(&kobj
->entry
);
128 kobj
->kset
= kset_get(kobj
->kset
);
133 * unlink - remove kobject from kset list.
136 * Remove the kobject from the kset list and decrement
137 * its parent's refcount.
138 * This is separated out, so we can use it in both
139 * kobject_del() and kobject_add() on error.
142 static void unlink(struct kobject
* kobj
)
145 down_write(&kobj
->kset
->subsys
->rwsem
);
146 list_del_init(&kobj
->entry
);
147 up_write(&kobj
->kset
->subsys
->rwsem
);
153 * kobject_add - add an object to the hierarchy.
157 int kobject_add(struct kobject
* kobj
)
160 struct kobject
* parent
;
162 if (!(kobj
= kobject_get(kobj
)))
165 kobj
->k_name
= kobj
->name
;
166 parent
= kobject_get(kobj
->parent
);
168 pr_debug("kobject %s: registering. parent: %s, set: %s\n",
169 kobject_name(kobj
), parent
? kobject_name(parent
) : "<NULL>",
170 kobj
->kset
? kobj
->kset
->kobj
.name
: "<NULL>" );
173 down_write(&kobj
->kset
->subsys
->rwsem
);
176 parent
= kobject_get(&kobj
->kset
->kobj
);
178 list_add_tail(&kobj
->entry
,&kobj
->kset
->list
);
179 up_write(&kobj
->kset
->subsys
->rwsem
);
181 kobj
->parent
= parent
;
183 error
= create_dir(kobj
);
189 kobject_hotplug(kobj
, KOBJ_ADD
);
197 * kobject_register - initialize and add an object.
198 * @kobj: object in question.
201 int kobject_register(struct kobject
* kobj
)
206 error
= kobject_add(kobj
);
208 printk("kobject_register failed for %s (%d)\n",
209 kobject_name(kobj
),error
);
219 * kobject_set_name - Set the name of an object
223 * If strlen(name) >= KOBJ_NAME_LEN, then use a dynamically allocated
224 * string that @kobj->k_name points to. Otherwise, use the static
228 int kobject_set_name(struct kobject
* kobj
, const char * fmt
, ...)
231 int limit
= KOBJ_NAME_LEN
;
238 * First, try the static array
240 need
= vsnprintf(kobj
->name
,limit
,fmt
,args
);
245 * Need more space? Allocate it and try again
248 name
= kmalloc(limit
,GFP_KERNEL
);
253 need
= vsnprintf(name
,limit
,fmt
,args
);
255 /* Still? Give up. */
263 /* Free the old name, if necessary. */
264 if (kobj
->k_name
&& kobj
->k_name
!= kobj
->name
)
267 /* Now, set the new name */
274 EXPORT_SYMBOL(kobject_set_name
);
278 * kobject_rename - change the name of an object
279 * @kobj: object in question.
280 * @new_name: object's new name
283 int kobject_rename(struct kobject
* kobj
, char *new_name
)
287 kobj
= kobject_get(kobj
);
290 error
= sysfs_rename_dir(kobj
, new_name
);
297 * kobject_del - unlink kobject from hierarchy.
301 void kobject_del(struct kobject
* kobj
)
303 kobject_hotplug(kobj
, KOBJ_REMOVE
);
304 sysfs_remove_dir(kobj
);
309 * kobject_unregister - remove object from hierarchy and decrement refcount.
310 * @kobj: object going away.
313 void kobject_unregister(struct kobject
* kobj
)
315 pr_debug("kobject %s: unregistering\n",kobject_name(kobj
));
321 * kobject_get - increment refcount for object.
325 struct kobject
* kobject_get(struct kobject
* kobj
)
328 kref_get(&kobj
->kref
);
333 * kobject_cleanup - free kobject resources.
337 void kobject_cleanup(struct kobject
* kobj
)
339 struct kobj_type
* t
= get_ktype(kobj
);
340 struct kset
* s
= kobj
->kset
;
341 struct kobject
* parent
= kobj
->parent
;
343 pr_debug("kobject %s: cleaning up\n",kobject_name(kobj
));
344 if (kobj
->k_name
!= kobj
->name
)
355 static void kobject_release(struct kref
*kref
)
357 kobject_cleanup(container_of(kref
, struct kobject
, kref
));
361 * kobject_put - decrement refcount for object.
364 * Decrement the refcount, and if 0, call kobject_cleanup().
366 void kobject_put(struct kobject
* kobj
)
369 kref_put(&kobj
->kref
, kobject_release
);
374 * kset_init - initialize a kset for use
378 void kset_init(struct kset
* k
)
380 kobject_init(&k
->kobj
);
381 INIT_LIST_HEAD(&k
->list
);
386 * kset_add - add a kset object to the hierarchy.
389 * Simply, this adds the kset's embedded kobject to the
391 * We also try to make sure that the kset's embedded kobject
392 * has a parent before it is added. We only care if the embedded
393 * kobject is not part of a kset itself, since kobject_add()
394 * assigns a parent in that case.
395 * If that is the case, and the kset has a controlling subsystem,
396 * then we set the kset's parent to be said subsystem.
399 int kset_add(struct kset
* k
)
401 if (!k
->kobj
.parent
&& !k
->kobj
.kset
&& k
->subsys
)
402 k
->kobj
.parent
= &k
->subsys
->kset
.kobj
;
404 return kobject_add(&k
->kobj
);
409 * kset_register - initialize and add a kset.
413 int kset_register(struct kset
* k
)
421 * kset_unregister - remove a kset.
425 void kset_unregister(struct kset
* k
)
427 kobject_unregister(&k
->kobj
);
432 * kset_find_obj - search for object in kset.
433 * @kset: kset we're looking in.
434 * @name: object's name.
436 * Lock kset via @kset->subsys, and iterate over @kset->list,
437 * looking for a matching kobject. If matching object is found
438 * take a reference and return the object.
441 struct kobject
* kset_find_obj(struct kset
* kset
, const char * name
)
443 struct list_head
* entry
;
444 struct kobject
* ret
= NULL
;
446 down_read(&kset
->subsys
->rwsem
);
447 list_for_each(entry
,&kset
->list
) {
448 struct kobject
* k
= to_kobj(entry
);
449 if (kobject_name(k
) && !strcmp(kobject_name(k
),name
)) {
450 ret
= kobject_get(k
);
454 up_read(&kset
->subsys
->rwsem
);
459 void subsystem_init(struct subsystem
* s
)
461 init_rwsem(&s
->rwsem
);
466 * subsystem_register - register a subsystem.
467 * @s: the subsystem we're registering.
469 * Once we register the subsystem, we want to make sure that
470 * the kset points back to this subsystem for correct usage of
474 int subsystem_register(struct subsystem
* s
)
479 pr_debug("subsystem %s: registering\n",s
->kset
.kobj
.name
);
481 if (!(error
= kset_add(&s
->kset
))) {
488 void subsystem_unregister(struct subsystem
* s
)
490 pr_debug("subsystem %s: unregistering\n",s
->kset
.kobj
.name
);
491 kset_unregister(&s
->kset
);
496 * subsystem_create_file - export sysfs attribute file.
498 * @a: subsystem attribute descriptor.
501 int subsys_create_file(struct subsystem
* s
, struct subsys_attribute
* a
)
505 error
= sysfs_create_file(&s
->kset
.kobj
,&a
->attr
);
513 * subsystem_remove_file - remove sysfs attribute file.
515 * @a: attribute desciptor.
518 void subsys_remove_file(struct subsystem
* s
, struct subsys_attribute
* a
)
521 sysfs_remove_file(&s
->kset
.kobj
,&a
->attr
);
526 EXPORT_SYMBOL(kobject_get_path
);
527 EXPORT_SYMBOL(kobject_init
);
528 EXPORT_SYMBOL(kobject_register
);
529 EXPORT_SYMBOL(kobject_unregister
);
530 EXPORT_SYMBOL(kobject_get
);
531 EXPORT_SYMBOL(kobject_put
);
532 EXPORT_SYMBOL(kobject_add
);
533 EXPORT_SYMBOL(kobject_del
);
534 EXPORT_SYMBOL(kobject_rename
);
536 EXPORT_SYMBOL(kset_register
);
537 EXPORT_SYMBOL(kset_unregister
);
538 EXPORT_SYMBOL(kset_find_obj
);
540 EXPORT_SYMBOL(subsystem_init
);
541 EXPORT_SYMBOL(subsystem_register
);
542 EXPORT_SYMBOL(subsystem_unregister
);
543 EXPORT_SYMBOL(subsys_create_file
);
544 EXPORT_SYMBOL(subsys_remove_file
);