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.
13 #include <linux/kobject.h>
14 #include <linux/string.h>
15 #include <linux/module.h>
16 #include <linux/stat.h>
17 #include <linux/slab.h>
20 * populate_dir - populate directory with attributes.
21 * @kobj: object we're working on.
23 * Most subsystems have a set of default attributes that
24 * are associated with an object that registers with them.
25 * This is a helper called during object registration that
26 * loops through the default attributes of the subsystem
27 * and creates attributes files for them in sysfs.
31 static int populate_dir(struct kobject * kobj)
33 struct kobj_type * t = get_ktype(kobj);
34 struct attribute * attr;
38 if (t && t->default_attrs) {
39 for (i = 0; (attr = t->default_attrs[i]) != NULL; i++) {
40 if ((error = sysfs_create_file(kobj,attr)))
47 static int create_dir(struct kobject * kobj)
50 if (kobject_name(kobj)) {
51 error = sysfs_create_dir(kobj);
53 if ((error = populate_dir(kobj)))
54 sysfs_remove_dir(kobj);
60 static inline struct kobject * to_kobj(struct list_head * entry)
62 return container_of(entry,struct kobject,entry);
65 static int get_kobj_path_length(struct kobject *kobj)
68 struct kobject * parent = kobj;
70 /* walk up the ancestors until we hit the one pointing to the
72 * Add 1 to strlen for leading '/' of each level.
75 if (kobject_name(parent) == NULL)
77 length += strlen(kobject_name(parent)) + 1;
78 parent = parent->parent;
83 static void fill_kobj_path(struct kobject *kobj, char *path, int length)
85 struct kobject * parent;
88 for (parent = kobj; parent; parent = parent->parent) {
89 int cur = strlen(kobject_name(parent));
90 /* back up enough to print this name with '/' */
92 strncpy (path + length, kobject_name(parent), cur);
93 *(path + --length) = '/';
96 pr_debug("%s: path = '%s'\n",__FUNCTION__,path);
100 * kobject_get_path - generate and return the path associated with a given kobj
101 * and kset pair. The result must be freed by the caller with kfree().
103 * @kobj: kobject in question, with which to build the path
104 * @gfp_mask: the allocation type used to allocate the path
106 char *kobject_get_path(struct kobject *kobj, gfp_t gfp_mask)
111 len = get_kobj_path_length(kobj);
114 path = kzalloc(len, gfp_mask);
117 fill_kobj_path(kobj, path, len);
121 EXPORT_SYMBOL_GPL(kobject_get_path);
124 * kobject_init - initialize object.
125 * @kobj: object in question.
127 void kobject_init(struct kobject * kobj)
131 kref_init(&kobj->kref);
132 INIT_LIST_HEAD(&kobj->entry);
133 init_waitqueue_head(&kobj->poll);
134 kobj->kset = kset_get(kobj->kset);
139 * unlink - remove kobject from kset list.
142 * Remove the kobject from the kset list and decrement
143 * its parent's refcount.
144 * This is separated out, so we can use it in both
145 * kobject_del() and kobject_add() on error.
148 static void unlink(struct kobject * kobj)
151 spin_lock(&kobj->kset->list_lock);
152 list_del_init(&kobj->entry);
153 spin_unlock(&kobj->kset->list_lock);
159 * kobject_add - add an object to the hierarchy.
163 int kobject_add(struct kobject * kobj)
166 struct kobject * parent;
168 if (!(kobj = kobject_get(kobj)))
171 kobj->k_name = kobj->name;
173 pr_debug("kobject attempted to be registered with no name!\n");
177 parent = kobject_get(kobj->parent);
179 pr_debug("kobject %s: registering. parent: %s, set: %s\n",
180 kobject_name(kobj), parent ? kobject_name(parent) : "<NULL>",
181 kobj->kset ? kobj->kset->kobj.name : "<NULL>" );
184 spin_lock(&kobj->kset->list_lock);
187 parent = kobject_get(&kobj->kset->kobj);
189 list_add_tail(&kobj->entry,&kobj->kset->list);
190 spin_unlock(&kobj->kset->list_lock);
192 kobj->parent = parent;
194 error = create_dir(kobj);
196 /* unlink does the kobject_put() for us */
201 /* be noisy on error issues */
202 if (error == -EEXIST)
203 printk("kobject_add failed for %s with -EEXIST, "
204 "don't try to register things with the "
205 "same name in the same directory.\n",
208 printk("kobject_add failed for %s (%d)\n",
209 kobject_name(kobj), error);
218 * kobject_register - initialize and add an object.
219 * @kobj: object in question.
222 int kobject_register(struct kobject * kobj)
227 error = kobject_add(kobj);
229 kobject_uevent(kobj, KOBJ_ADD);
236 * kobject_set_name - Set the name of an object
238 * @fmt: format string used to build the name
240 * If strlen(name) >= KOBJ_NAME_LEN, then use a dynamically allocated
241 * string that @kobj->k_name points to. Otherwise, use the static
244 int kobject_set_name(struct kobject * kobj, const char * fmt, ...)
247 int limit = KOBJ_NAME_LEN;
253 * First, try the static array
256 need = vsnprintf(kobj->name,limit,fmt,args);
262 * Need more space? Allocate it and try again
265 name = kmalloc(limit,GFP_KERNEL);
271 need = vsnprintf(name,limit,fmt,args);
274 /* Still? Give up. */
282 /* Free the old name, if necessary. */
283 if (kobj->k_name && kobj->k_name != kobj->name)
286 /* Now, set the new name */
292 EXPORT_SYMBOL(kobject_set_name);
296 * kobject_rename - change the name of an object
297 * @kobj: object in question.
298 * @new_name: object's new name
301 int kobject_rename(struct kobject * kobj, const char *new_name)
305 kobj = kobject_get(kobj);
308 error = sysfs_rename_dir(kobj, new_name);
315 * kobject_move - move object to another parent
316 * @kobj: object in question.
317 * @new_parent: object's new parent (can be NULL)
320 int kobject_move(struct kobject *kobj, struct kobject *new_parent)
323 struct kobject *old_parent;
324 const char *devpath = NULL;
325 char *devpath_string = NULL;
328 kobj = kobject_get(kobj);
331 new_parent = kobject_get(new_parent);
334 new_parent = kobject_get(&kobj->kset->kobj);
336 /* old object path */
337 devpath = kobject_get_path(kobj, GFP_KERNEL);
342 devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
343 if (!devpath_string) {
347 sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
348 envp[0] = devpath_string;
350 error = sysfs_move_dir(kobj, new_parent);
353 old_parent = kobj->parent;
354 kobj->parent = new_parent;
355 kobject_put(old_parent);
356 kobject_uevent_env(kobj, KOBJ_MOVE, envp);
359 kfree(devpath_string);
365 * kobject_del - unlink kobject from hierarchy.
369 void kobject_del(struct kobject * kobj)
373 sysfs_remove_dir(kobj);
378 * kobject_unregister - remove object from hierarchy and decrement refcount.
379 * @kobj: object going away.
382 void kobject_unregister(struct kobject * kobj)
386 pr_debug("kobject %s: unregistering\n",kobject_name(kobj));
387 kobject_uevent(kobj, KOBJ_REMOVE);
393 * kobject_get - increment refcount for object.
397 struct kobject * kobject_get(struct kobject * kobj)
400 kref_get(&kobj->kref);
405 * kobject_cleanup - free kobject resources.
409 void kobject_cleanup(struct kobject * kobj)
411 struct kobj_type * t = get_ktype(kobj);
412 struct kset * s = kobj->kset;
413 struct kobject * parent = kobj->parent;
415 pr_debug("kobject %s: cleaning up\n",kobject_name(kobj));
416 if (kobj->k_name != kobj->name)
427 static void kobject_release(struct kref *kref)
429 kobject_cleanup(container_of(kref, struct kobject, kref));
433 * kobject_put - decrement refcount for object.
436 * Decrement the refcount, and if 0, call kobject_cleanup().
438 void kobject_put(struct kobject * kobj)
441 kref_put(&kobj->kref, kobject_release);
445 static void dir_release(struct kobject *kobj)
450 static struct kobj_type dir_ktype = {
451 .release = dir_release,
453 .default_attrs = NULL,
457 * kobject_add_dir - add sub directory of object.
458 * @parent: object in which a directory is created.
459 * @name: directory name.
461 * Add a plain directory object as child of given object.
463 struct kobject *kobject_add_dir(struct kobject *parent, const char *name)
471 k = kzalloc(sizeof(*k), GFP_KERNEL);
476 k->ktype = &dir_ktype;
477 kobject_set_name(k, name);
478 ret = kobject_register(k);
480 printk(KERN_WARNING "kobject_add_dir: "
481 "kobject_register error: %d\n", ret);
490 * kset_init - initialize a kset for use
494 void kset_init(struct kset * k)
496 kobject_init(&k->kobj);
497 INIT_LIST_HEAD(&k->list);
498 spin_lock_init(&k->list_lock);
503 * kset_add - add a kset object to the hierarchy.
506 * Simply, this adds the kset's embedded kobject to the
508 * We also try to make sure that the kset's embedded kobject
509 * has a parent before it is added. We only care if the embedded
510 * kobject is not part of a kset itself, since kobject_add()
511 * assigns a parent in that case.
512 * If that is the case, and the kset has a controlling subsystem,
513 * then we set the kset's parent to be said subsystem.
516 int kset_add(struct kset * k)
518 if (!k->kobj.parent && !k->kobj.kset && k->subsys)
519 k->kobj.parent = &k->subsys->kset.kobj;
521 return kobject_add(&k->kobj);
526 * kset_register - initialize and add a kset.
530 int kset_register(struct kset * k)
540 * kset_unregister - remove a kset.
544 void kset_unregister(struct kset * k)
548 kobject_unregister(&k->kobj);
553 * kset_find_obj - search for object in kset.
554 * @kset: kset we're looking in.
555 * @name: object's name.
557 * Lock kset via @kset->subsys, and iterate over @kset->list,
558 * looking for a matching kobject. If matching object is found
559 * take a reference and return the object.
562 struct kobject * kset_find_obj(struct kset * kset, const char * name)
564 struct list_head * entry;
565 struct kobject * ret = NULL;
567 spin_lock(&kset->list_lock);
568 list_for_each(entry,&kset->list) {
569 struct kobject * k = to_kobj(entry);
570 if (kobject_name(k) && !strcmp(kobject_name(k),name)) {
571 ret = kobject_get(k);
575 spin_unlock(&kset->list_lock);
580 void subsystem_init(struct subsystem * s)
582 init_rwsem(&s->rwsem);
587 * subsystem_register - register a subsystem.
588 * @s: the subsystem we're registering.
590 * Once we register the subsystem, we want to make sure that
591 * the kset points back to this subsystem for correct usage of
595 int subsystem_register(struct subsystem * s)
603 pr_debug("subsystem %s: registering\n",s->kset.kobj.name);
605 if (!(error = kset_add(&s->kset))) {
612 void subsystem_unregister(struct subsystem * s)
616 pr_debug("subsystem %s: unregistering\n",s->kset.kobj.name);
617 kset_unregister(&s->kset);
622 * subsystem_create_file - export sysfs attribute file.
624 * @a: subsystem attribute descriptor.
627 int subsys_create_file(struct subsystem * s, struct subsys_attribute * a)
635 error = sysfs_create_file(&s->kset.kobj,&a->attr);
643 * subsystem_remove_file - remove sysfs attribute file.
645 * @a: attribute desciptor.
648 void subsys_remove_file(struct subsystem * s, struct subsys_attribute * a)
651 sysfs_remove_file(&s->kset.kobj,&a->attr);
657 EXPORT_SYMBOL(kobject_init);
658 EXPORT_SYMBOL(kobject_register);
659 EXPORT_SYMBOL(kobject_unregister);
660 EXPORT_SYMBOL(kobject_get);
661 EXPORT_SYMBOL(kobject_put);
662 EXPORT_SYMBOL(kobject_add);
663 EXPORT_SYMBOL(kobject_del);
665 EXPORT_SYMBOL(kset_register);
666 EXPORT_SYMBOL(kset_unregister);
668 EXPORT_SYMBOL(subsystem_register);
669 EXPORT_SYMBOL(subsystem_unregister);
670 EXPORT_SYMBOL(subsys_create_file);