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);
327 static int kobject_add_varg(struct kobject *kobj, struct kobject *parent,
328 const char *fmt, va_list vargs)
334 retval = kobject_set_name_vargs(kobj, fmt, aq);
337 printk(KERN_ERR "kobject: can not set name properly!\n");
340 kobj->parent = parent;
341 return kobject_add(kobj);
345 * kobject_add_ng - the main kobject add function
346 * @kobj: the kobject to add
347 * @parent: pointer to the parent of the kobject.
348 * @fmt: format to name the kobject with.
350 * The kobject name is set and added to the kobject hierarchy in this
353 * If @parent is set, then the parent of the @kobj will be set to it.
354 * If @parent is NULL, then the parent of the @kobj will be set to the
355 * kobject associted with the kset assigned to this kobject. If no kset
356 * is assigned to the kobject, then the kobject will be located in the
357 * root of the sysfs tree.
359 * If this function returns an error, kobject_put() must be called to
360 * properly clean up the memory associated with the object.
362 * If the function is successful, the only way to properly clean up the
363 * memory is with a call to kobject_del(), in which case, a call to
364 * kobject_put() is not necessary (kobject_del() does the final
365 * kobject_put() to call the release function in the ktype's release
368 * Under no instance should the kobject that is passed to this function
369 * be directly freed with a call to kfree(), that can leak memory.
371 * Note, no uevent will be created with this call, the caller should set
372 * up all of the necessary sysfs files for the object and then call
373 * kobject_uevent() with the UEVENT_ADD parameter to ensure that
374 * userspace is properly notified of this kobject's creation.
376 int kobject_add_ng(struct kobject *kobj, struct kobject *parent,
377 const char *fmt, ...)
386 retval = kobject_add_varg(kobj, parent, fmt, args);
391 EXPORT_SYMBOL(kobject_add_ng);
394 * kobject_init_and_add - initialize a kobject structure and add it to the kobject hierarchy
395 * @kobj: pointer to the kobject to initialize
396 * @ktype: pointer to the ktype for this kobject.
397 * @parent: pointer to the parent of this kobject.
398 * @fmt: the name of the kobject.
400 * This function combines the call to kobject_init_ng() and
401 * kobject_add_ng(). The same type of error handling after a call to
402 * kobject_add_ng() and kobject lifetime rules are the same here.
404 int kobject_init_and_add(struct kobject *kobj, struct kobj_type *ktype,
405 struct kobject *parent, const char *fmt, ...)
410 kobject_init_ng(kobj, ktype);
413 retval = kobject_add_varg(kobj, parent, fmt, args);
418 EXPORT_SYMBOL_GPL(kobject_init_and_add);
421 * kobject_rename - change the name of an object
422 * @kobj: object in question.
423 * @new_name: object's new name
426 int kobject_rename(struct kobject * kobj, const char *new_name)
429 const char *devpath = NULL;
430 char *devpath_string = NULL;
433 kobj = kobject_get(kobj);
439 /* see if this name is already in use */
441 struct kobject *temp_kobj;
442 temp_kobj = kset_find_obj(kobj->kset, new_name);
444 printk(KERN_WARNING "kobject '%s' cannot be renamed "
445 "to '%s' as '%s' is already in existence.\n",
446 kobject_name(kobj), new_name, new_name);
447 kobject_put(temp_kobj);
452 devpath = kobject_get_path(kobj, GFP_KERNEL);
457 devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
458 if (!devpath_string) {
462 sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
463 envp[0] = devpath_string;
466 error = sysfs_rename_dir(kobj, new_name);
468 /* This function is mostly/only used for network interface.
469 * Some hotplug package track interfaces by their name and
470 * therefore want to know when the name is changed by the user. */
472 kobject_uevent_env(kobj, KOBJ_MOVE, envp);
475 kfree(devpath_string);
483 * kobject_move - move object to another parent
484 * @kobj: object in question.
485 * @new_parent: object's new parent (can be NULL)
488 int kobject_move(struct kobject *kobj, struct kobject *new_parent)
491 struct kobject *old_parent;
492 const char *devpath = NULL;
493 char *devpath_string = NULL;
496 kobj = kobject_get(kobj);
499 new_parent = kobject_get(new_parent);
502 new_parent = kobject_get(&kobj->kset->kobj);
504 /* old object path */
505 devpath = kobject_get_path(kobj, GFP_KERNEL);
510 devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
511 if (!devpath_string) {
515 sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
516 envp[0] = devpath_string;
518 error = sysfs_move_dir(kobj, new_parent);
521 old_parent = kobj->parent;
522 kobj->parent = new_parent;
524 kobject_put(old_parent);
525 kobject_uevent_env(kobj, KOBJ_MOVE, envp);
527 kobject_put(new_parent);
529 kfree(devpath_string);
535 * kobject_del - unlink kobject from hierarchy.
539 void kobject_del(struct kobject * kobj)
543 sysfs_remove_dir(kobj);
548 * kobject_unregister - remove object from hierarchy and decrement refcount.
549 * @kobj: object going away.
552 void kobject_unregister(struct kobject * kobj)
556 pr_debug("kobject %s: unregistering\n",kobject_name(kobj));
557 kobject_uevent(kobj, KOBJ_REMOVE);
563 * kobject_get - increment refcount for object.
567 struct kobject * kobject_get(struct kobject * kobj)
570 kref_get(&kobj->kref);
575 * kobject_cleanup - free kobject resources.
576 * @kobj: object to cleanup
578 static void kobject_cleanup(struct kobject *kobj)
580 struct kobj_type * t = get_ktype(kobj);
581 struct kset * s = kobj->kset;
582 struct kobject * parent = kobj->parent;
583 const char *name = kobj->k_name;
585 pr_debug("kobject %s: cleaning up\n",kobject_name(kobj));
586 if (t && t->release) {
588 /* If we have a release function, we can guess that this was
589 * not a statically allocated kobject, so we should be safe to
598 static void kobject_release(struct kref *kref)
600 kobject_cleanup(container_of(kref, struct kobject, kref));
604 * kobject_put - decrement refcount for object.
607 * Decrement the refcount, and if 0, call kobject_cleanup().
609 void kobject_put(struct kobject * kobj)
612 kref_put(&kobj->kref, kobject_release);
616 static void dir_release(struct kobject *kobj)
621 static struct kobj_type dir_ktype = {
622 .release = dir_release,
624 .default_attrs = NULL,
628 * kobject_kset_add_dir - add sub directory of object.
629 * @kset: kset the directory is belongs to.
630 * @parent: object in which a directory is created.
631 * @name: directory name.
633 * Add a plain directory object as child of given object.
635 struct kobject *kobject_kset_add_dir(struct kset *kset,
636 struct kobject *parent, const char *name)
644 k = kzalloc(sizeof(*k), GFP_KERNEL);
650 k->ktype = &dir_ktype;
651 kobject_set_name(k, name);
652 ret = kobject_register(k);
654 printk(KERN_WARNING "%s: kobject_register error: %d\n",
664 * kobject_add_dir - add sub directory of object.
665 * @parent: object in which a directory is created.
666 * @name: directory name.
668 * Add a plain directory object as child of given object.
670 struct kobject *kobject_add_dir(struct kobject *parent, const char *name)
672 return kobject_kset_add_dir(NULL, parent, name);
676 * kset_init - initialize a kset for use
680 void kset_init(struct kset * k)
682 kobject_init(&k->kobj);
683 INIT_LIST_HEAD(&k->list);
684 spin_lock_init(&k->list_lock);
689 * kset_add - add a kset object to the hierarchy.
693 int kset_add(struct kset * k)
695 return kobject_add(&k->kobj);
700 * kset_register - initialize and add a kset.
704 int kset_register(struct kset * k)
715 kobject_uevent(&k->kobj, KOBJ_ADD);
721 * kset_unregister - remove a kset.
725 void kset_unregister(struct kset * k)
729 kobject_unregister(&k->kobj);
734 * kset_find_obj - search for object in kset.
735 * @kset: kset we're looking in.
736 * @name: object's name.
738 * Lock kset via @kset->subsys, and iterate over @kset->list,
739 * looking for a matching kobject. If matching object is found
740 * take a reference and return the object.
743 struct kobject * kset_find_obj(struct kset * kset, const char * name)
745 struct list_head * entry;
746 struct kobject * ret = NULL;
748 spin_lock(&kset->list_lock);
749 list_for_each(entry,&kset->list) {
750 struct kobject * k = to_kobj(entry);
751 if (kobject_name(k) && !strcmp(kobject_name(k),name)) {
752 ret = kobject_get(k);
756 spin_unlock(&kset->list_lock);
760 int subsystem_register(struct kset *s)
762 return kset_register(s);
765 void subsystem_unregister(struct kset *s)
771 * subsystem_create_file - export sysfs attribute file.
773 * @a: subsystem attribute descriptor.
776 int subsys_create_file(struct kset *s, struct subsys_attribute *a)
784 error = sysfs_create_file(&s->kobj, &a->attr);
790 EXPORT_SYMBOL(kobject_init);
791 EXPORT_SYMBOL(kobject_register);
792 EXPORT_SYMBOL(kobject_unregister);
793 EXPORT_SYMBOL(kobject_get);
794 EXPORT_SYMBOL(kobject_put);
795 EXPORT_SYMBOL(kobject_add);
796 EXPORT_SYMBOL(kobject_del);
798 EXPORT_SYMBOL(kset_register);
799 EXPORT_SYMBOL(kset_unregister);
801 EXPORT_SYMBOL(subsystem_register);
802 EXPORT_SYMBOL(subsystem_unregister);
803 EXPORT_SYMBOL(subsys_create_file);