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);
237 * kobject_set_name - Set the name of a kobject
238 * @kobj: kobject to name
239 * @fmt: format string used to build the name
241 * This sets the name of the kobject. If you have already added the
242 * kobject to the system, you must call kobject_rename() in order to
243 * change the name of the kobject.
245 int kobject_set_name(struct kobject * kobj, const char * fmt, ...)
253 /* find out how big a buffer we need */
254 name = kmalloc(1024, GFP_KERNEL);
260 need = vsnprintf(name, 1024, fmt, args);
264 /* Allocate the new space and copy the string in */
266 name = kmalloc(limit, GFP_KERNEL);
272 need = vsnprintf(name, limit, fmt, args);
275 /* something wrong with the string we copied? */
282 /* Free the old name, if necessary. */
285 /* Now, set the new name */
290 EXPORT_SYMBOL(kobject_set_name);
293 * kobject_rename - change the name of an object
294 * @kobj: object in question.
295 * @new_name: object's new name
298 int kobject_rename(struct kobject * kobj, const char *new_name)
301 const char *devpath = NULL;
302 char *devpath_string = NULL;
305 kobj = kobject_get(kobj);
311 /* see if this name is already in use */
313 struct kobject *temp_kobj;
314 temp_kobj = kset_find_obj(kobj->kset, new_name);
316 printk(KERN_WARNING "kobject '%s' cannot be renamed "
317 "to '%s' as '%s' is already in existence.\n",
318 kobject_name(kobj), new_name, new_name);
319 kobject_put(temp_kobj);
324 devpath = kobject_get_path(kobj, GFP_KERNEL);
329 devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
330 if (!devpath_string) {
334 sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
335 envp[0] = devpath_string;
338 error = sysfs_rename_dir(kobj, new_name);
340 /* This function is mostly/only used for network interface.
341 * Some hotplug package track interfaces by their name and
342 * therefore want to know when the name is changed by the user. */
344 kobject_uevent_env(kobj, KOBJ_MOVE, envp);
347 kfree(devpath_string);
355 * kobject_move - move object to another parent
356 * @kobj: object in question.
357 * @new_parent: object's new parent (can be NULL)
360 int kobject_move(struct kobject *kobj, struct kobject *new_parent)
363 struct kobject *old_parent;
364 const char *devpath = NULL;
365 char *devpath_string = NULL;
368 kobj = kobject_get(kobj);
371 new_parent = kobject_get(new_parent);
374 new_parent = kobject_get(&kobj->kset->kobj);
376 /* old object path */
377 devpath = kobject_get_path(kobj, GFP_KERNEL);
382 devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
383 if (!devpath_string) {
387 sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
388 envp[0] = devpath_string;
390 error = sysfs_move_dir(kobj, new_parent);
393 old_parent = kobj->parent;
394 kobj->parent = new_parent;
396 kobject_put(old_parent);
397 kobject_uevent_env(kobj, KOBJ_MOVE, envp);
399 kobject_put(new_parent);
401 kfree(devpath_string);
407 * kobject_del - unlink kobject from hierarchy.
411 void kobject_del(struct kobject * kobj)
415 sysfs_remove_dir(kobj);
420 * kobject_unregister - remove object from hierarchy and decrement refcount.
421 * @kobj: object going away.
424 void kobject_unregister(struct kobject * kobj)
428 pr_debug("kobject %s: unregistering\n",kobject_name(kobj));
429 kobject_uevent(kobj, KOBJ_REMOVE);
435 * kobject_get - increment refcount for object.
439 struct kobject * kobject_get(struct kobject * kobj)
442 kref_get(&kobj->kref);
447 * kobject_cleanup - free kobject resources.
451 void kobject_cleanup(struct kobject * kobj)
453 struct kobj_type * t = get_ktype(kobj);
454 struct kset * s = kobj->kset;
455 struct kobject * parent = kobj->parent;
456 const char *name = kobj->k_name;
458 pr_debug("kobject %s: cleaning up\n",kobject_name(kobj));
459 if (t && t->release) {
461 /* If we have a release function, we can guess that this was
462 * not a statically allocated kobject, so we should be safe to
471 static void kobject_release(struct kref *kref)
473 kobject_cleanup(container_of(kref, struct kobject, kref));
477 * kobject_put - decrement refcount for object.
480 * Decrement the refcount, and if 0, call kobject_cleanup().
482 void kobject_put(struct kobject * kobj)
485 kref_put(&kobj->kref, kobject_release);
489 static void dir_release(struct kobject *kobj)
494 static struct kobj_type dir_ktype = {
495 .release = dir_release,
497 .default_attrs = NULL,
501 * kobject_kset_add_dir - add sub directory of object.
502 * @kset: kset the directory is belongs to.
503 * @parent: object in which a directory is created.
504 * @name: directory name.
506 * Add a plain directory object as child of given object.
508 struct kobject *kobject_kset_add_dir(struct kset *kset,
509 struct kobject *parent, const char *name)
517 k = kzalloc(sizeof(*k), GFP_KERNEL);
523 k->ktype = &dir_ktype;
524 kobject_set_name(k, name);
525 ret = kobject_register(k);
527 printk(KERN_WARNING "%s: kobject_register error: %d\n",
537 * kobject_add_dir - add sub directory of object.
538 * @parent: object in which a directory is created.
539 * @name: directory name.
541 * Add a plain directory object as child of given object.
543 struct kobject *kobject_add_dir(struct kobject *parent, const char *name)
545 return kobject_kset_add_dir(NULL, parent, name);
549 * kset_init - initialize a kset for use
553 void kset_init(struct kset * k)
555 kobject_init(&k->kobj);
556 INIT_LIST_HEAD(&k->list);
557 spin_lock_init(&k->list_lock);
562 * kset_add - add a kset object to the hierarchy.
566 int kset_add(struct kset * k)
568 return kobject_add(&k->kobj);
573 * kset_register - initialize and add a kset.
577 int kset_register(struct kset * k)
588 kobject_uevent(&k->kobj, KOBJ_ADD);
594 * kset_unregister - remove a kset.
598 void kset_unregister(struct kset * k)
602 kobject_unregister(&k->kobj);
607 * kset_find_obj - search for object in kset.
608 * @kset: kset we're looking in.
609 * @name: object's name.
611 * Lock kset via @kset->subsys, and iterate over @kset->list,
612 * looking for a matching kobject. If matching object is found
613 * take a reference and return the object.
616 struct kobject * kset_find_obj(struct kset * kset, const char * name)
618 struct list_head * entry;
619 struct kobject * ret = NULL;
621 spin_lock(&kset->list_lock);
622 list_for_each(entry,&kset->list) {
623 struct kobject * k = to_kobj(entry);
624 if (kobject_name(k) && !strcmp(kobject_name(k),name)) {
625 ret = kobject_get(k);
629 spin_unlock(&kset->list_lock);
633 int subsystem_register(struct kset *s)
635 return kset_register(s);
638 void subsystem_unregister(struct kset *s)
644 * subsystem_create_file - export sysfs attribute file.
646 * @a: subsystem attribute descriptor.
649 int subsys_create_file(struct kset *s, struct subsys_attribute *a)
657 error = sysfs_create_file(&s->kobj, &a->attr);
663 EXPORT_SYMBOL(kobject_init);
664 EXPORT_SYMBOL(kobject_register);
665 EXPORT_SYMBOL(kobject_unregister);
666 EXPORT_SYMBOL(kobject_get);
667 EXPORT_SYMBOL(kobject_put);
668 EXPORT_SYMBOL(kobject_add);
669 EXPORT_SYMBOL(kobject_del);
671 EXPORT_SYMBOL(kset_register);
672 EXPORT_SYMBOL(kset_unregister);
674 EXPORT_SYMBOL(subsystem_register);
675 EXPORT_SYMBOL(subsystem_unregister);
676 EXPORT_SYMBOL(subsys_create_file);