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);
328 * kobject_rename - change the name of an object
329 * @kobj: object in question.
330 * @new_name: object's new name
333 int kobject_rename(struct kobject * kobj, const char *new_name)
336 const char *devpath = NULL;
337 char *devpath_string = NULL;
340 kobj = kobject_get(kobj);
346 /* see if this name is already in use */
348 struct kobject *temp_kobj;
349 temp_kobj = kset_find_obj(kobj->kset, new_name);
351 printk(KERN_WARNING "kobject '%s' cannot be renamed "
352 "to '%s' as '%s' is already in existence.\n",
353 kobject_name(kobj), new_name, new_name);
354 kobject_put(temp_kobj);
359 devpath = kobject_get_path(kobj, GFP_KERNEL);
364 devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
365 if (!devpath_string) {
369 sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
370 envp[0] = devpath_string;
373 error = sysfs_rename_dir(kobj, new_name);
375 /* This function is mostly/only used for network interface.
376 * Some hotplug package track interfaces by their name and
377 * therefore want to know when the name is changed by the user. */
379 kobject_uevent_env(kobj, KOBJ_MOVE, envp);
382 kfree(devpath_string);
390 * kobject_move - move object to another parent
391 * @kobj: object in question.
392 * @new_parent: object's new parent (can be NULL)
395 int kobject_move(struct kobject *kobj, struct kobject *new_parent)
398 struct kobject *old_parent;
399 const char *devpath = NULL;
400 char *devpath_string = NULL;
403 kobj = kobject_get(kobj);
406 new_parent = kobject_get(new_parent);
409 new_parent = kobject_get(&kobj->kset->kobj);
411 /* old object path */
412 devpath = kobject_get_path(kobj, GFP_KERNEL);
417 devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
418 if (!devpath_string) {
422 sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
423 envp[0] = devpath_string;
425 error = sysfs_move_dir(kobj, new_parent);
428 old_parent = kobj->parent;
429 kobj->parent = new_parent;
431 kobject_put(old_parent);
432 kobject_uevent_env(kobj, KOBJ_MOVE, envp);
434 kobject_put(new_parent);
436 kfree(devpath_string);
442 * kobject_del - unlink kobject from hierarchy.
446 void kobject_del(struct kobject * kobj)
450 sysfs_remove_dir(kobj);
455 * kobject_unregister - remove object from hierarchy and decrement refcount.
456 * @kobj: object going away.
459 void kobject_unregister(struct kobject * kobj)
463 pr_debug("kobject %s: unregistering\n",kobject_name(kobj));
464 kobject_uevent(kobj, KOBJ_REMOVE);
470 * kobject_get - increment refcount for object.
474 struct kobject * kobject_get(struct kobject * kobj)
477 kref_get(&kobj->kref);
482 * kobject_cleanup - free kobject resources.
483 * @kobj: object to cleanup
485 static void kobject_cleanup(struct kobject *kobj)
487 struct kobj_type * t = get_ktype(kobj);
488 struct kset * s = kobj->kset;
489 struct kobject * parent = kobj->parent;
490 const char *name = kobj->k_name;
492 pr_debug("kobject %s: cleaning up\n",kobject_name(kobj));
493 if (t && t->release) {
495 /* If we have a release function, we can guess that this was
496 * not a statically allocated kobject, so we should be safe to
505 static void kobject_release(struct kref *kref)
507 kobject_cleanup(container_of(kref, struct kobject, kref));
511 * kobject_put - decrement refcount for object.
514 * Decrement the refcount, and if 0, call kobject_cleanup().
516 void kobject_put(struct kobject * kobj)
519 kref_put(&kobj->kref, kobject_release);
523 static void dir_release(struct kobject *kobj)
528 static struct kobj_type dir_ktype = {
529 .release = dir_release,
531 .default_attrs = NULL,
535 * kobject_kset_add_dir - add sub directory of object.
536 * @kset: kset the directory is belongs to.
537 * @parent: object in which a directory is created.
538 * @name: directory name.
540 * Add a plain directory object as child of given object.
542 struct kobject *kobject_kset_add_dir(struct kset *kset,
543 struct kobject *parent, const char *name)
551 k = kzalloc(sizeof(*k), GFP_KERNEL);
557 k->ktype = &dir_ktype;
558 kobject_set_name(k, name);
559 ret = kobject_register(k);
561 printk(KERN_WARNING "%s: kobject_register error: %d\n",
571 * kobject_add_dir - add sub directory of object.
572 * @parent: object in which a directory is created.
573 * @name: directory name.
575 * Add a plain directory object as child of given object.
577 struct kobject *kobject_add_dir(struct kobject *parent, const char *name)
579 return kobject_kset_add_dir(NULL, parent, name);
583 * kset_init - initialize a kset for use
587 void kset_init(struct kset * k)
589 kobject_init(&k->kobj);
590 INIT_LIST_HEAD(&k->list);
591 spin_lock_init(&k->list_lock);
596 * kset_add - add a kset object to the hierarchy.
600 int kset_add(struct kset * k)
602 return kobject_add(&k->kobj);
607 * kset_register - initialize and add a kset.
611 int kset_register(struct kset * k)
622 kobject_uevent(&k->kobj, KOBJ_ADD);
628 * kset_unregister - remove a kset.
632 void kset_unregister(struct kset * k)
636 kobject_unregister(&k->kobj);
641 * kset_find_obj - search for object in kset.
642 * @kset: kset we're looking in.
643 * @name: object's name.
645 * Lock kset via @kset->subsys, and iterate over @kset->list,
646 * looking for a matching kobject. If matching object is found
647 * take a reference and return the object.
650 struct kobject * kset_find_obj(struct kset * kset, const char * name)
652 struct list_head * entry;
653 struct kobject * ret = NULL;
655 spin_lock(&kset->list_lock);
656 list_for_each(entry,&kset->list) {
657 struct kobject * k = to_kobj(entry);
658 if (kobject_name(k) && !strcmp(kobject_name(k),name)) {
659 ret = kobject_get(k);
663 spin_unlock(&kset->list_lock);
667 int subsystem_register(struct kset *s)
669 return kset_register(s);
672 void subsystem_unregister(struct kset *s)
678 * subsystem_create_file - export sysfs attribute file.
680 * @a: subsystem attribute descriptor.
683 int subsys_create_file(struct kset *s, struct subsys_attribute *a)
691 error = sysfs_create_file(&s->kobj, &a->attr);
697 EXPORT_SYMBOL(kobject_init);
698 EXPORT_SYMBOL(kobject_register);
699 EXPORT_SYMBOL(kobject_unregister);
700 EXPORT_SYMBOL(kobject_get);
701 EXPORT_SYMBOL(kobject_put);
702 EXPORT_SYMBOL(kobject_add);
703 EXPORT_SYMBOL(kobject_del);
705 EXPORT_SYMBOL(kset_register);
706 EXPORT_SYMBOL(kset_unregister);
708 EXPORT_SYMBOL(subsystem_register);
709 EXPORT_SYMBOL(subsystem_unregister);
710 EXPORT_SYMBOL(subsys_create_file);