696 lines
14 KiB
C
696 lines
14 KiB
C
/*
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* kobject.c - library routines for handling generic kernel objects
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*
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* Copyright (c) 2002-2003 Patrick Mochel <mochel@osdl.org>
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*
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* This file is released under the GPLv2.
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*
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*
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* Please see the file Documentation/kobject.txt for critical information
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* about using the kobject interface.
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*/
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#include <linux/kobject.h>
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#include <linux/string.h>
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#include <linux/module.h>
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#include <linux/stat.h>
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#include <linux/slab.h>
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/**
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* populate_dir - populate directory with attributes.
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* @kobj: object we're working on.
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*
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* Most subsystems have a set of default attributes that
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* are associated with an object that registers with them.
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* This is a helper called during object registration that
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* loops through the default attributes of the subsystem
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* and creates attributes files for them in sysfs.
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*
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*/
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static int populate_dir(struct kobject * kobj)
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{
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struct kobj_type * t = get_ktype(kobj);
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struct attribute * attr;
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int error = 0;
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int i;
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if (t && t->default_attrs) {
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for (i = 0; (attr = t->default_attrs[i]) != NULL; i++) {
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if ((error = sysfs_create_file(kobj,attr)))
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break;
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}
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}
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return error;
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}
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static int create_dir(struct kobject * kobj, struct dentry *shadow_parent)
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{
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int error = 0;
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if (kobject_name(kobj)) {
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error = sysfs_create_dir(kobj, shadow_parent);
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if (!error) {
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if ((error = populate_dir(kobj)))
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sysfs_remove_dir(kobj);
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}
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}
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return error;
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}
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static inline struct kobject * to_kobj(struct list_head * entry)
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{
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return container_of(entry,struct kobject,entry);
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}
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static int get_kobj_path_length(struct kobject *kobj)
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{
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int length = 1;
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struct kobject * parent = kobj;
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/* walk up the ancestors until we hit the one pointing to the
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* root.
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* Add 1 to strlen for leading '/' of each level.
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*/
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do {
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if (kobject_name(parent) == NULL)
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return 0;
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length += strlen(kobject_name(parent)) + 1;
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parent = parent->parent;
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} while (parent);
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return length;
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}
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static void fill_kobj_path(struct kobject *kobj, char *path, int length)
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{
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struct kobject * parent;
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--length;
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for (parent = kobj; parent; parent = parent->parent) {
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int cur = strlen(kobject_name(parent));
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/* back up enough to print this name with '/' */
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length -= cur;
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strncpy (path + length, kobject_name(parent), cur);
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*(path + --length) = '/';
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}
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pr_debug("%s: path = '%s'\n",__FUNCTION__,path);
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}
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/**
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* kobject_get_path - generate and return the path associated with a given kobj and kset pair.
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*
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* @kobj: kobject in question, with which to build the path
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* @gfp_mask: the allocation type used to allocate the path
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*
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* The result must be freed by the caller with kfree().
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*/
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char *kobject_get_path(struct kobject *kobj, gfp_t gfp_mask)
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{
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char *path;
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int len;
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len = get_kobj_path_length(kobj);
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if (len == 0)
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return NULL;
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path = kzalloc(len, gfp_mask);
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if (!path)
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return NULL;
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fill_kobj_path(kobj, path, len);
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return path;
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}
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EXPORT_SYMBOL_GPL(kobject_get_path);
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/**
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* kobject_init - initialize object.
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* @kobj: object in question.
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*/
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void kobject_init(struct kobject * kobj)
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{
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if (!kobj)
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return;
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kref_init(&kobj->kref);
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INIT_LIST_HEAD(&kobj->entry);
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init_waitqueue_head(&kobj->poll);
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kobj->kset = kset_get(kobj->kset);
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}
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/**
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* unlink - remove kobject from kset list.
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* @kobj: kobject.
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*
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* Remove the kobject from the kset list and decrement
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* its parent's refcount.
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* This is separated out, so we can use it in both
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* kobject_del() and kobject_add() on error.
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*/
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static void unlink(struct kobject * kobj)
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{
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if (kobj->kset) {
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spin_lock(&kobj->kset->list_lock);
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list_del_init(&kobj->entry);
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spin_unlock(&kobj->kset->list_lock);
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}
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kobject_put(kobj);
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}
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/**
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* kobject_shadow_add - add an object to the hierarchy.
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* @kobj: object.
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* @shadow_parent: sysfs directory to add to.
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*/
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int kobject_shadow_add(struct kobject * kobj, struct dentry *shadow_parent)
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{
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int error = 0;
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struct kobject * parent;
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if (!(kobj = kobject_get(kobj)))
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return -ENOENT;
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if (!kobj->k_name)
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kobj->k_name = kobj->name;
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if (!*kobj->k_name) {
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pr_debug("kobject attempted to be registered with no name!\n");
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WARN_ON(1);
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kobject_put(kobj);
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return -EINVAL;
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}
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parent = kobject_get(kobj->parent);
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pr_debug("kobject %s: registering. parent: %s, set: %s\n",
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kobject_name(kobj), parent ? kobject_name(parent) : "<NULL>",
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kobj->kset ? kobj->kset->kobj.name : "<NULL>" );
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if (kobj->kset) {
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spin_lock(&kobj->kset->list_lock);
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if (!parent)
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parent = kobject_get(&kobj->kset->kobj);
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list_add_tail(&kobj->entry,&kobj->kset->list);
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spin_unlock(&kobj->kset->list_lock);
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kobj->parent = parent;
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}
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error = create_dir(kobj, shadow_parent);
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if (error) {
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/* unlink does the kobject_put() for us */
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unlink(kobj);
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kobject_put(parent);
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/* be noisy on error issues */
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if (error == -EEXIST)
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printk("kobject_add failed for %s with -EEXIST, "
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"don't try to register things with the "
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"same name in the same directory.\n",
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kobject_name(kobj));
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else
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printk("kobject_add failed for %s (%d)\n",
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kobject_name(kobj), error);
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dump_stack();
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}
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return error;
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}
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/**
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* kobject_add - add an object to the hierarchy.
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* @kobj: object.
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*/
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int kobject_add(struct kobject * kobj)
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{
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return kobject_shadow_add(kobj, NULL);
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}
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/**
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* kobject_register - initialize and add an object.
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* @kobj: object in question.
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*/
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int kobject_register(struct kobject * kobj)
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{
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int error = -EINVAL;
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if (kobj) {
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kobject_init(kobj);
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error = kobject_add(kobj);
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if (!error)
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kobject_uevent(kobj, KOBJ_ADD);
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}
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return error;
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}
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/**
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* kobject_set_name - Set the name of an object
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* @kobj: object.
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* @fmt: format string used to build the name
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*
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* If strlen(name) >= KOBJ_NAME_LEN, then use a dynamically allocated
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* string that @kobj->k_name points to. Otherwise, use the static
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* @kobj->name array.
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*/
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int kobject_set_name(struct kobject * kobj, const char * fmt, ...)
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{
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int error = 0;
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int limit = KOBJ_NAME_LEN;
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int need;
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va_list args;
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char * name;
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/*
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* First, try the static array
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*/
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va_start(args,fmt);
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need = vsnprintf(kobj->name,limit,fmt,args);
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va_end(args);
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if (need < limit)
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name = kobj->name;
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else {
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/*
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* Need more space? Allocate it and try again
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*/
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limit = need + 1;
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name = kmalloc(limit,GFP_KERNEL);
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if (!name) {
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error = -ENOMEM;
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goto Done;
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}
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va_start(args,fmt);
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need = vsnprintf(name,limit,fmt,args);
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va_end(args);
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/* Still? Give up. */
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if (need >= limit) {
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kfree(name);
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error = -EFAULT;
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goto Done;
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}
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}
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/* Free the old name, if necessary. */
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if (kobj->k_name && kobj->k_name != kobj->name)
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kfree(kobj->k_name);
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/* Now, set the new name */
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kobj->k_name = name;
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Done:
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return error;
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}
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EXPORT_SYMBOL(kobject_set_name);
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/**
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* kobject_rename - change the name of an object
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* @kobj: object in question.
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* @new_name: object's new name
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*/
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int kobject_rename(struct kobject * kobj, const char *new_name)
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{
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int error = 0;
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const char *devpath = NULL;
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char *devpath_string = NULL;
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char *envp[2];
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kobj = kobject_get(kobj);
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if (!kobj)
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return -EINVAL;
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if (!kobj->parent)
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return -EINVAL;
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devpath = kobject_get_path(kobj, GFP_KERNEL);
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if (!devpath) {
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error = -ENOMEM;
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goto out;
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}
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devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
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if (!devpath_string) {
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error = -ENOMEM;
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goto out;
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}
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sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
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envp[0] = devpath_string;
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envp[1] = NULL;
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/* Note : if we want to send the new name alone, not the full path,
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* we could probably use kobject_name(kobj); */
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error = sysfs_rename_dir(kobj, kobj->parent->dentry, new_name);
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/* This function is mostly/only used for network interface.
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* Some hotplug package track interfaces by their name and
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* therefore want to know when the name is changed by the user. */
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if (!error)
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kobject_uevent_env(kobj, KOBJ_MOVE, envp);
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out:
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kfree(devpath_string);
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kfree(devpath);
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kobject_put(kobj);
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return error;
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}
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/**
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* kobject_rename - change the name of an object
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* @kobj: object in question.
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* @new_parent: object's new parent
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* @new_name: object's new name
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*/
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int kobject_shadow_rename(struct kobject * kobj, struct dentry *new_parent,
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const char *new_name)
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{
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int error = 0;
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kobj = kobject_get(kobj);
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if (!kobj)
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return -EINVAL;
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error = sysfs_rename_dir(kobj, new_parent, new_name);
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kobject_put(kobj);
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return error;
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}
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/**
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* kobject_move - move object to another parent
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* @kobj: object in question.
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* @new_parent: object's new parent (can be NULL)
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*/
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int kobject_move(struct kobject *kobj, struct kobject *new_parent)
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{
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int error;
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struct kobject *old_parent;
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const char *devpath = NULL;
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char *devpath_string = NULL;
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char *envp[2];
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kobj = kobject_get(kobj);
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if (!kobj)
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return -EINVAL;
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new_parent = kobject_get(new_parent);
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if (!new_parent) {
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if (kobj->kset)
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new_parent = kobject_get(&kobj->kset->kobj);
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}
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/* old object path */
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devpath = kobject_get_path(kobj, GFP_KERNEL);
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if (!devpath) {
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error = -ENOMEM;
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goto out;
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}
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devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
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if (!devpath_string) {
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error = -ENOMEM;
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goto out;
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}
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sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
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envp[0] = devpath_string;
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envp[1] = NULL;
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error = sysfs_move_dir(kobj, new_parent);
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if (error)
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goto out;
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old_parent = kobj->parent;
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kobj->parent = new_parent;
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new_parent = NULL;
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kobject_put(old_parent);
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kobject_uevent_env(kobj, KOBJ_MOVE, envp);
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out:
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kobject_put(new_parent);
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kobject_put(kobj);
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kfree(devpath_string);
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kfree(devpath);
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return error;
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}
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/**
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* kobject_del - unlink kobject from hierarchy.
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* @kobj: object.
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*/
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void kobject_del(struct kobject * kobj)
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{
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if (!kobj)
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return;
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sysfs_remove_dir(kobj);
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unlink(kobj);
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}
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/**
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* kobject_unregister - remove object from hierarchy and decrement refcount.
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* @kobj: object going away.
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*/
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void kobject_unregister(struct kobject * kobj)
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{
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if (!kobj)
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return;
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pr_debug("kobject %s: unregistering\n",kobject_name(kobj));
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kobject_uevent(kobj, KOBJ_REMOVE);
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kobject_del(kobj);
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kobject_put(kobj);
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}
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/**
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* kobject_get - increment refcount for object.
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* @kobj: object.
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*/
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struct kobject * kobject_get(struct kobject * kobj)
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{
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if (kobj)
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kref_get(&kobj->kref);
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return kobj;
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}
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/**
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* kobject_cleanup - free kobject resources.
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* @kobj: object.
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*/
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void kobject_cleanup(struct kobject * kobj)
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{
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struct kobj_type * t = get_ktype(kobj);
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struct kset * s = kobj->kset;
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struct kobject * parent = kobj->parent;
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pr_debug("kobject %s: cleaning up\n",kobject_name(kobj));
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if (kobj->k_name != kobj->name)
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kfree(kobj->k_name);
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kobj->k_name = NULL;
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if (t && t->release)
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t->release(kobj);
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if (s)
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kset_put(s);
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kobject_put(parent);
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}
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static void kobject_release(struct kref *kref)
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{
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kobject_cleanup(container_of(kref, struct kobject, kref));
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}
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/**
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* kobject_put - decrement refcount for object.
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* @kobj: object.
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*
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* Decrement the refcount, and if 0, call kobject_cleanup().
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*/
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void kobject_put(struct kobject * kobj)
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{
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if (kobj)
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kref_put(&kobj->kref, kobject_release);
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}
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static void dir_release(struct kobject *kobj)
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{
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kfree(kobj);
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}
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static struct kobj_type dir_ktype = {
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.release = dir_release,
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.sysfs_ops = NULL,
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.default_attrs = NULL,
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};
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/**
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* kobject_kset_add_dir - add sub directory of object.
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* @kset: kset the directory is belongs to.
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* @parent: object in which a directory is created.
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* @name: directory name.
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*
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* Add a plain directory object as child of given object.
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*/
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struct kobject *kobject_kset_add_dir(struct kset *kset,
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struct kobject *parent, const char *name)
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{
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struct kobject *k;
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int ret;
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if (!parent)
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return NULL;
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k = kzalloc(sizeof(*k), GFP_KERNEL);
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if (!k)
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return NULL;
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k->kset = kset;
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k->parent = parent;
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k->ktype = &dir_ktype;
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kobject_set_name(k, name);
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ret = kobject_register(k);
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if (ret < 0) {
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printk(KERN_WARNING "%s: kobject_register error: %d\n",
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__func__, ret);
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kobject_del(k);
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return NULL;
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}
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return k;
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}
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/**
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* kobject_add_dir - add sub directory of object.
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* @parent: object in which a directory is created.
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* @name: directory name.
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*
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* Add a plain directory object as child of given object.
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*/
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struct kobject *kobject_add_dir(struct kobject *parent, const char *name)
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{
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return kobject_kset_add_dir(NULL, parent, name);
|
|
}
|
|
|
|
/**
|
|
* kset_init - initialize a kset for use
|
|
* @k: kset
|
|
*/
|
|
|
|
void kset_init(struct kset * k)
|
|
{
|
|
kobject_init(&k->kobj);
|
|
INIT_LIST_HEAD(&k->list);
|
|
spin_lock_init(&k->list_lock);
|
|
}
|
|
|
|
|
|
/**
|
|
* kset_add - add a kset object to the hierarchy.
|
|
* @k: kset.
|
|
*/
|
|
|
|
int kset_add(struct kset * k)
|
|
{
|
|
return kobject_add(&k->kobj);
|
|
}
|
|
|
|
|
|
/**
|
|
* kset_register - initialize and add a kset.
|
|
* @k: kset.
|
|
*/
|
|
|
|
int kset_register(struct kset * k)
|
|
{
|
|
if (!k)
|
|
return -EINVAL;
|
|
kset_init(k);
|
|
return kset_add(k);
|
|
}
|
|
|
|
|
|
/**
|
|
* kset_unregister - remove a kset.
|
|
* @k: kset.
|
|
*/
|
|
|
|
void kset_unregister(struct kset * k)
|
|
{
|
|
if (!k)
|
|
return;
|
|
kobject_unregister(&k->kobj);
|
|
}
|
|
|
|
|
|
/**
|
|
* kset_find_obj - search for object in kset.
|
|
* @kset: kset we're looking in.
|
|
* @name: object's name.
|
|
*
|
|
* Lock kset via @kset->subsys, and iterate over @kset->list,
|
|
* looking for a matching kobject. If matching object is found
|
|
* take a reference and return the object.
|
|
*/
|
|
|
|
struct kobject * kset_find_obj(struct kset * kset, const char * name)
|
|
{
|
|
struct list_head * entry;
|
|
struct kobject * ret = NULL;
|
|
|
|
spin_lock(&kset->list_lock);
|
|
list_for_each(entry,&kset->list) {
|
|
struct kobject * k = to_kobj(entry);
|
|
if (kobject_name(k) && !strcmp(kobject_name(k),name)) {
|
|
ret = kobject_get(k);
|
|
break;
|
|
}
|
|
}
|
|
spin_unlock(&kset->list_lock);
|
|
return ret;
|
|
}
|
|
|
|
void subsystem_init(struct kset *s)
|
|
{
|
|
kset_init(s);
|
|
}
|
|
|
|
int subsystem_register(struct kset *s)
|
|
{
|
|
return kset_register(s);
|
|
}
|
|
|
|
void subsystem_unregister(struct kset *s)
|
|
{
|
|
kset_unregister(s);
|
|
}
|
|
|
|
/**
|
|
* subsystem_create_file - export sysfs attribute file.
|
|
* @s: subsystem.
|
|
* @a: subsystem attribute descriptor.
|
|
*/
|
|
|
|
int subsys_create_file(struct kset *s, struct subsys_attribute *a)
|
|
{
|
|
int error = 0;
|
|
|
|
if (!s || !a)
|
|
return -EINVAL;
|
|
|
|
if (subsys_get(s)) {
|
|
error = sysfs_create_file(&s->kobj, &a->attr);
|
|
subsys_put(s);
|
|
}
|
|
return error;
|
|
}
|
|
|
|
EXPORT_SYMBOL(kobject_init);
|
|
EXPORT_SYMBOL(kobject_register);
|
|
EXPORT_SYMBOL(kobject_unregister);
|
|
EXPORT_SYMBOL(kobject_get);
|
|
EXPORT_SYMBOL(kobject_put);
|
|
EXPORT_SYMBOL(kobject_add);
|
|
EXPORT_SYMBOL(kobject_del);
|
|
|
|
EXPORT_SYMBOL(kset_register);
|
|
EXPORT_SYMBOL(kset_unregister);
|
|
|
|
EXPORT_SYMBOL(subsystem_register);
|
|
EXPORT_SYMBOL(subsystem_unregister);
|
|
EXPORT_SYMBOL(subsys_create_file);
|