kobject.c

Lib files of linux kernel

		error = -ENOMEM;
		goto out;
	}
	sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
	envp[0] = devpath_string;
	envp[1] = NULL;

	error = sysfs_rename_dir(kobj, new_name);

	/* This function is mostly/only used for network interface.
	 * Some hotplug package track interfaces by their name and
	 * therefore want to know when the name is changed by the user. */
	if (!error)
		kobject_uevent_env(kobj, KOBJ_MOVE, envp);

out:
	kfree(devpath_string);
	kfree(devpath);
	kobject_put(kobj);

	return error;
}
EXPORT_SYMBOL_GPL(kobject_rename);

/**
 * kobject_move - move object to another parent
 * @kobj: object in question.
 * @new_parent: object's new parent (can be NULL)
 */
int kobject_move(struct kobject *kobj, struct kobject *new_parent)
{
	int error;
	struct kobject *old_parent;
	const char *devpath = NULL;
	char *devpath_string = NULL;
	char *envp[2];

	kobj = kobject_get(kobj);
	if (!kobj)
		return -EINVAL;
	new_parent = kobject_get(new_parent);
	if (!new_parent) {
		if (kobj->kset)
			new_parent = kobject_get(&kobj->kset->kobj);
	}
	/* old object path */
	devpath = kobject_get_path(kobj, GFP_KERNEL);
	if (!devpath) {
		error = -ENOMEM;
		goto out;
	}
	devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
	if (!devpath_string) {
		error = -ENOMEM;
		goto out;
	}
	sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
	envp[0] = devpath_string;
	envp[1] = NULL;
	error = sysfs_move_dir(kobj, new_parent);
	if (error)
		goto out;
	old_parent = kobj->parent;
	kobj->parent = new_parent;
	new_parent = NULL;
	kobject_put(old_parent);
	kobject_uevent_env(kobj, KOBJ_MOVE, envp);
out:
	kobject_put(new_parent);
	kobject_put(kobj);
	kfree(devpath_string);
	kfree(devpath);
	return error;
}

/**
 * kobject_del - unlink kobject from hierarchy.
 * @kobj: object.
 */
void kobject_del(struct kobject *kobj)
{
	if (!kobj)
		return;

	sysfs_remove_dir(kobj);
	kobj->state_in_sysfs = 0;
	kobj_kset_leave(kobj);
	kobject_put(kobj->parent);
	kobj->parent = NULL;
}

/**
 * kobject_get - increment refcount for object.
 * @kobj: object.
 */
struct kobject *kobject_get(struct kobject *kobj)
{
	if (kobj)
		kref_get(&kobj->kref);
	return kobj;
}

/*
 * kobject_cleanup - free kobject resources.
 * @kobj: object to cleanup
 */
static void kobject_cleanup(struct kobject *kobj)
{
	struct kobj_type *t = get_ktype(kobj);
	const char *name = kobj->name;

	pr_debug("kobject: '%s' (%p): %s\n",
		 kobject_name(kobj), kobj, __func__);

	if (t && !t->release)
		pr_debug("kobject: '%s' (%p): does not have a release() "
			 "function, it is broken and must be fixed.\n",
			 kobject_name(kobj), kobj);

	/* send "remove" if the caller did not do it but sent "add" */
	if (kobj->state_add_uevent_sent && !kobj->state_remove_uevent_sent) {
		pr_debug("kobject: '%s' (%p): auto cleanup 'remove' event\n",
			 kobject_name(kobj), kobj);
		kobject_uevent(kobj, KOBJ_REMOVE);
	}

	/* remove from sysfs if the caller did not do it */
	if (kobj->state_in_sysfs) {
		pr_debug("kobject: '%s' (%p): auto cleanup kobject_del\n",
			 kobject_name(kobj), kobj);
		kobject_del(kobj);
	}

	if (t && t->release) {
		pr_debug("kobject: '%s' (%p): calling ktype release\n",
			 kobject_name(kobj), kobj);
		t->release(kobj);
	}

	/* free name if we allocated it */
	if (name) {
		pr_debug("kobject: '%s': free name\n", name);
		kfree(name);
	}
}

static void kobject_release(struct kref *kref)
{
	kobject_cleanup(container_of(kref, struct kobject, kref));
}

/**
 * kobject_put - decrement refcount for object.
 * @kobj: object.
 *
 * Decrement the refcount, and if 0, call kobject_cleanup().
 */
void kobject_put(struct kobject *kobj)
{
	if (kobj) {
		if (!kobj->state_initialized)
			WARN(1, KERN_WARNING "kobject: '%s' (%p): is not "
			       "initialized, yet kobject_put() is being "
			       "called.\n", kobject_name(kobj), kobj);
		kref_put(&kobj->kref, kobject_release);
	}
}

static void dynamic_kobj_release(struct kobject *kobj)
{
	pr_debug("kobject: (%p): %s\n", kobj, __func__);
	kfree(kobj);
}

static struct kobj_type dynamic_kobj_ktype = {
	.release	= dynamic_kobj_release,
	.sysfs_ops	= &kobj_sysfs_ops,
};

/**
 * kobject_create - create a struct kobject dynamically
 *
 * This function creates a kobject structure dynamically and sets it up
 * to be a "dynamic" kobject with a default release function set up.
 *
 * If the kobject was not able to be created, NULL will be returned.
 * The kobject structure returned from here must be cleaned up with a
 * call to kobject_put() and not kfree(), as kobject_init() has
 * already been called on this structure.
 */
struct kobject *kobject_create(void)
{
	struct kobject *kobj;

	kobj = kzalloc(sizeof(*kobj), GFP_KERNEL);
	if (!kobj)
		return NULL;

	kobject_init(kobj, &dynamic_kobj_ktype);
	return kobj;
}

/**
 * kobject_create_and_add - create a struct kobject dynamically and register it with sysfs
 *
 * @name: the name for the kset
 * @parent: the parent kobject of this kobject, if any.
 *
 * This function creates a kobject structure dynamically and registers it
 * with sysfs.  When you are finished with this structure, call
 * kobject_put() and the structure will be dynamically freed when
 * it is no longer being used.
 *
 * If the kobject was not able to be created, NULL will be returned.
 */
struct kobject *kobject_create_and_add(const char *name, struct kobject *parent)
{
	struct kobject *kobj;
	int retval;

	kobj = kobject_create();
	if (!kobj)
		return NULL;

	retval = kobject_add(kobj, parent, "%s", name);
	if (retval) {
		printk(KERN_WARNING "%s: kobject_add error: %d\n",
		       __func__, retval);
		kobject_put(kobj);
		kobj = NULL;
	}
	return kobj;
}
EXPORT_SYMBOL_GPL(kobject_create_and_add);

/**
 * kset_init - initialize a kset for use
 * @k: kset
 */
void kset_init(struct kset *k)
{
	kobject_init_internal(&k->kobj);
	INIT_LIST_HEAD(&k->list);
	spin_lock_init(&k->list_lock);
}

/* default kobject attribute operations */
static ssize_t kobj_attr_show(struct kobject *kobj, struct attribute *attr,
			      char *buf)
{
	struct kobj_attribute *kattr;
	ssize_t ret = -EIO;

	kattr = container_of(attr, struct kobj_attribute, attr);
	if (kattr->show)
		ret = kattr->show(kobj, kattr, buf);
	return ret;
}

static ssize_t kobj_attr_store(struct kobject *kobj, struct attribute *attr,
			       const char *buf, size_t count)
{
	struct kobj_attribute *kattr;
	ssize_t ret = -EIO;

	kattr = container_of(attr, struct kobj_attribute, attr);
	if (kattr->store)
		ret = kattr->store(kobj, kattr, buf, count);
	return ret;
}

struct sysfs_ops kobj_sysfs_ops = {
	.show	= kobj_attr_show,
	.store	= kobj_attr_store,
};

/**
 * kset_register - initialize and add a kset.
 * @k: kset.
 */
int kset_register(struct kset *k)
{
	int err;

	if (!k)
		return -EINVAL;

	kset_init(k);
	err = kobject_add_internal(&k->kobj);
	if (err)
		return err;
	kobject_uevent(&k->kobj, KOBJ_ADD);
	return 0;
}

/**
 * kset_unregister - remove a kset.
 * @k: kset.
 */
void kset_unregister(struct kset *k)
{
	if (!k)
		return;
	kobject_put(&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 kobject *k;
	struct kobject *ret = NULL;

	spin_lock(&kset->list_lock);
	list_for_each_entry(k, &kset->list, entry) {
		if (kobject_name(k) && !strcmp(kobject_name(k), name)) {
			ret = kobject_get(k);
			break;
		}
	}
	spin_unlock(&kset->list_lock);
	return ret;
}

static void kset_release(struct kobject *kobj)
{
	struct kset *kset = container_of(kobj, struct kset, kobj);
	pr_debug("kobject: '%s' (%p): %s\n",
		 kobject_name(kobj), kobj, __func__);
	kfree(kset);
}

static struct kobj_type kset_ktype = {
	.sysfs_ops	= &kobj_sysfs_ops,
	.release = kset_release,
};

/**
 * kset_create - create a struct kset dynamically
 *
 * @name: the name for the kset
 * @uevent_ops: a struct kset_uevent_ops for the kset
 * @parent_kobj: the parent kobject of this kset, if any.
 *
 * This function creates a kset structure dynamically.  This structure can
 * then be registered with the system and show up in sysfs with a call to
 * kset_register().  When you are finished with this structure, if
 * kset_register() has been called, call kset_unregister() and the
 * structure will be dynamically freed when it is no longer being used.
 *
 * If the kset was not able to be created, NULL will be returned.
 */
static struct kset *kset_create(const char *name,
				struct kset_uevent_ops *uevent_ops,
				struct kobject *parent_kobj)
{
	struct kset *kset;

	kset = kzalloc(sizeof(*kset), GFP_KERNEL);
	if (!kset)
		return NULL;
	kobject_set_name(&kset->kobj, name);
	kset->uevent_ops = uevent_ops;
	kset->kobj.parent = parent_kobj;

	/*
	 * The kobject of this kset will have a type of kset_ktype and belong to
	 * no kset itself.  That way we can properly free it when it is
	 * finished being used.
	 */
	kset->kobj.ktype = &kset_ktype;
	kset->kobj.kset = NULL;

	return kset;
}

/**
 * kset_create_and_add - create a struct kset dynamically and add it to sysfs
 *
 * @name: the name for the kset
 * @uevent_ops: a struct kset_uevent_ops for the kset
 * @parent_kobj: the parent kobject of this kset, if any.
 *
 * This function creates a kset structure dynamically and registers it
 * with sysfs.  When you are finished with this structure, call
 * kset_unregister() and the structure will be dynamically freed when it
 * is no longer being used.
 *
 * If the kset was not able to be created, NULL will be returned.
 */
struct kset *kset_create_and_add(const char *name,
				 struct kset_uevent_ops *uevent_ops,
				 struct kobject *parent_kobj)
{
	struct kset *kset;
	int error;

	kset = kset_create(name, uevent_ops, parent_kobj);
	if (!kset)
		return NULL;
	error = kset_register(kset);
	if (error) {
		kfree(kset);
		return NULL;
	}
	return kset;
}
EXPORT_SYMBOL_GPL(kset_create_and_add);

EXPORT_SYMBOL(kobject_get);
EXPORT_SYMBOL(kobject_put);
EXPORT_SYMBOL(kobject_del);

EXPORT_SYMBOL(kset_register);
EXPORT_SYMBOL(kset_unregister);