/*
* kobject.c - library routines for handling generic kernel objects
*
* Copyright (c) 2002-2003 Patrick Mochel <mochel@osdl.org>
* Copyright (c) 2006-2007 Greg Kroah-Hartman <greg@kroah.com>
* Copyright (c) 2006-2007 Novell Inc.
*
* This file is released under the GPLv2.
*
*
* Please see the file Documentation/kobject.txt for critical information
* about using the kobject interface.
*/
#include <linux/kobject.h>
#include <linux/string.h>
#include <linux/module.h>
#include <linux/stat.h>
#include <linux/slab.h>
/**
* populate_dir - populate directory with attributes.
* @kobj: object we're working on.
*
* Most subsystems have a set of default attributes that
* are associated with an object that registers with them.
* This is a helper called during object registration that
* loops through the default attributes of the subsystem
* and creates attributes files for them in sysfs.
*
*/
static int populate_dir(struct kobject * kobj)
{
struct kobj_type * t = get_ktype(kobj);
struct attribute * attr;
int error = 0;
int i;
if (t && t->default_attrs) {
for (i = 0; (attr = t->default_attrs[i]) != NULL; i++) {
if ((error = sysfs_create_file(kobj,attr)))
break;
}
}
return error;
}
static int create_dir(struct kobject * kobj)
{
int error = 0;
if (kobject_name(kobj)) {
error = sysfs_create_dir(kobj);
if (!error) {
if ((error = populate_dir(kobj)))
sysfs_remove_dir(kobj);
}
}
return error;
}
static inline struct kobject * to_kobj(struct list_head * entry)
{
return container_of(entry,struct kobject,entry);
}
static int get_kobj_path_length(struct kobject *kobj)
{
int length = 1;
struct kobject * parent = kobj;
/* walk up the ancestors until we hit the one pointing to the
* root.
* Add 1 to strlen for leading '/' of each level.
*/
do {
if (kobject_name(parent) == NULL)
return 0;
length += strlen(kobject_name(parent)) + 1;
parent = parent->parent;
} while (parent);
return length;
}
static void fill_kobj_path(struct kobject *kobj, char *path, int length)
{
struct kobject * parent;
--length;
for (parent = kobj; parent; parent = parent->parent) {
int cur = strlen(kobject_name(parent));
/* back up enough to print this name with '/' */
length -= cur;
strncpy (path + length, kobject_name(parent), cur);
*(path + --length) = '/';
}
pr_debug("%s: path = '%s'\n",__FUNCTION__,path);
}
/**
* kobject_get_path - generate and return the path associated with a given kobj and kset pair.
*
* @kobj: kobject in question, with which to build the path
* @gfp_mask: the allocation type used to allocate the path
*
* The result must be freed by the caller with kfree().
*/
char *kobject_get_path(struct kobject *kobj, gfp_t gfp_mask)
{
char *path;
int len;
len = get_kobj_path_length(kobj);
if (len == 0)
return NULL;
path = kzalloc(len, gfp_mask);
if (!path)
return NULL;
fill_kobj_path(kobj, path, len);
return path;
}
EXPORT_SYMBOL_GPL(kobject_get_path);
/**
* kobject_init - initialize object.
* @kobj: object in question.
*/
void kobject_init(struct kobject * kobj)
{
if (!kobj)
return;
kref_init(&kobj->kref);
INIT_LIST_HEAD(&kobj->entry);
}
/**
* unlink - remove kobject from kset list.
* @kobj: kobject.
*
* Remove the kobject from the kset list and decrement
* its parent's refcount.
* This is separated out, so we can use it in both
* kobject_del() and kobject_add() on error.
*/
static void unlink(struct kobject * kobj)
{
if (kobj->kset) {
spin_lock(&kobj->kset->list_lock);
list_del_init(&kobj->entry);
spin_unlock(&kobj->kset->list_lock);
}
kobject_put(kobj);
}
/**
* kobject_add - add an object to the hierarchy.
* @kobj: object.
*/
int kobject_add(struct kobject * kobj)
{
int error = 0;
struct kobject * parent;
if (!(kobj = kobject_get(kobj)))
return -ENOENT;
if (!kobj->k_name)
kobject_set_name(kobj, "NO_NAME");
if (!*kobj->k_name) {
pr_debug("kobject attempted to be registered with no name!\n");
WARN_ON(1);
kobject_put(kobj);
return -EINVAL;
}
parent = kobject_get(kobj->parent);
pr_debug("kobject %s: registering. parent: %s, set: %s\n",
kobject_name(kobj), parent ? kobject_name(parent) : "<NULL>",
kobj->kset ? kobject_name(&kobj->kset->kobj) : "<NULL>" );
if (kobj->kset) {
kobj->kset = kset_get(kobj->kset);
if (!parent) {
parent = kobject_get(&kobj->kset->kobj);
/*
* If the kset is our parent, get a second
* reference, we drop both the kset and the
* parent ref on cleanup
*/
kobject_get(parent);
}
spin_lock(&kobj->kset->list_lock);
list_add_tail(&kobj->entry, &kobj->kset->list);
spin_unlock(&kobj->kset->list_lock);
kobj->parent = parent;
}
error = create_dir(kobj);
if (error) {
/* unlink does the kobject_put() for us */
unlink(kobj);
kobject_put(parent);
/* be noisy on error issues */
if (error == -EEXIST)
printk(KERN_ERR "kobject_add failed for %s with "
"-EEXIST, don't try to register things with "
"the same name in the same directory.\n",
kobject_name(kobj));
else
printk(KERN_ERR "kobject_add failed for %s (%d)\n",
kobject_name(kobj), error);
dump_stack();
}
return error;
}
/**
* kobject_register - initialize and add an object.
* @kobj: object in question.
*/
int kobject_register(struct kobject * kobj)
{
int error = -EINVAL;
if (kobj) {
kobject_init(kobj);
error = kobject_add(kobj);
if (!error)
kobject_uevent(kobj, KOBJ_ADD);
}
return error;
}
/**
* kobject_set_name_vargs - Set the name of an kobject
* @kobj: struct kobject to set the name of
* @fmt: format string used to build the name
* @vargs: vargs to format the string.
*/
static int kobject_set_name_vargs(struct kobject *kobj, const char *fmt,
va_list vargs)
{
va_list aq;
char *name;
va_copy(aq, vargs);
name = kvasprintf(GFP_KERNEL, fmt, vargs);
va_end(aq);
if (!name)
return -ENOMEM;
/* Free the old name, if necessary. */
kfree(kobj->k_name);
/* Now, set the new name */
kobj->k_name = name;
return 0;
}
/**
* kobject_set_name - Set the name of a kobject
* @kobj: struct kobject to set the name of
* @fmt: format string used to build the name
*
* This sets the name of the kobject. If you have already added the
* kobject to the system, you must call kobject_rename() in order to
* change the name of the kobject.
*/
int kobject_set_name(struct kobject *kobj, const char *fmt, ...)
{
va_list args;
int retval;
va_start(args, fmt);
retval = kobject_set_name_vargs(kobj, fmt, args);
va_end(args);
return retval;
}
EXPORT_SYMBOL(kobject_set_name);
/**
* kobject_init_ng - initialize a kobject structure
* @kobj: pointer to the kobject to initialize
* @ktype: pointer to the ktype for this kobject.
*
* This function will properly initialize a kobject such that it can then
* be passed to the kobject_add() call.
*
* After this function is called, the kobject MUST be cleaned up by a call
* to kobject_put(), not by a call to kfree directly to ensure that all of
* the memory is cleaned up properly.
*/
void kobject_init_ng(struct kobject *kobj, struct kobj_type *ktype)
{
char *err_str;
if (!kobj) {
err_str = "invalid kobject pointer!";
goto error;
}
if (!ktype) {
err_str = "must have a ktype to be initialized properly!\n";
goto error;
}
if (atomic_read(&kobj->kref.refcount)) {
/* do not error out as sometimes we can recover */
printk(KERN_ERR "kobject: reference count is already set, "
"something is seriously wrong.\n");
dump_stack();
}
kref_init(&kobj->kref);
INIT_LIST_HEAD(&kobj->entry);
kobj->ktype = ktype;
return;
error:
printk(KERN_ERR "kobject: %s\n", err_str);
dump_stack();
}
EXPORT_SYMBOL(kobject_init_ng);
static int kobject_add_varg(struct kobject *kobj, struct kobject *parent,
const char *fmt, va_list vargs)
{
va_list aq;
int retval;
va_copy(aq, vargs);
retval = kobject_set_name_vargs(kobj, fmt, aq);
va_end(aq);
if (retval) {
printk(KERN_ERR "kobject: can not set name properly!\n");
return retval;
}
kobj->parent = parent;
return kobject_add(kobj);
}
/**
* kobject_add_ng - the main kobject add function
* @kobj: the kobject to add
* @parent: pointer to the parent of the kobject.
* @fmt: format to name the kobject with.
*
* The kobject name is set and added to the kobject hierarchy in this
* function.
*
* If @parent is set, then the parent of the @kobj will be set to it.
* If @parent is NULL, then the parent of the @kobj will be set to the
* kobject associted with the kset assigned to this kobject. If no kset
* is assigned to the kobject, then the kobject will be located in the
* root of the sysfs tree.
*
* If this function returns an error, kobject_put() must be called to
* properly clean up the memory associated with the object.
*
* If the function is successful, the only way to properly clean up the
* memory is with a call to kobject_del(), in which case, a call to
* kobject_put() is not necessary (kobject_del() does the final
* kobject_put() to call the release function in the ktype's release
* pointer.)
*
* Under no instance should the kobject that is passed to this function
* be directly freed with a call to kfree(), that can leak memory.
*
* Note, no uevent will be created with this call, the caller should set
* up all of the necessary sysfs files for the object and then call
* kobject_uevent() with the UEVENT_ADD parameter to ensure that
* userspace is properly notified of this kobject's creation.
*/
int kobject_add_ng(struct kobject *kobj, struct kobject *parent,
const char *fmt, ...)
{
va_list args;
int retval;
if (!kobj)
return -EINVAL;
va_start(args, fmt);
retval = kobject_add_varg(kobj, parent, fmt, args);
va_end(args);
return retval;
}
EXPORT_SYMBOL(kobject_add_ng);
/**
* kobject_init_and_add - initialize a kobject structure and add it to the kobject hierarchy
* @kobj: pointer to the kobject to initialize
* @ktype: pointer to the ktype for this kobject.
* @parent: pointer to the parent of this kobject.
* @fmt: the name of the kobject.
*
* This function combines the call to kobject_init_ng() and
* kobject_add_ng(). The same type of error handling after a call to
* kobject_add_ng() and kobject lifetime rules are the same here.
*/
int kobject_init_and_add(struct kobject *kobj, struct kobj_type *ktype,
struct kobject *parent, const char *fmt, ...)
{
va_list args;
int retval;
kobject_init_ng(kobj, ktype);
va_start(args, fmt);
retval = kobject_add_varg(kobj, parent, fmt, args);
va_end(args);
return retval;
}
EXPORT_SYMBOL_GPL(kobject_init_and_add);
/**
* kobject_rename - change the name of an object
* @kobj: object in question.
* @new_name: object's new name
*/
int kobject_rename(struct kobject * kobj, const char *new_name)
{
int error = 0;
const char *devpath = NULL;
char *devpath_string = NULL;
char *envp[2];
kobj = kobject_get(kobj);
if (!kobj)
return -EINVAL;
if (!kobj->parent)
return -EINVAL;
/* see if this name is already in use */
if (kobj->kset) {
struct kobject *temp_kobj;
temp_kobj = kset_find_obj(kobj->kset, new_name);
if (temp_kobj) {
printk(KERN_WARNING "kobject '%s' cannot be renamed "
"to '%s' as '%s' is already in existence.\n",
kobject_name(kobj), new_name, new_name);
kobject_put(temp_kobj);
return -EINVAL;
}
}
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_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;
}
/**
* 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);
unlink(kobj);
}
/**
* kobject_unregister - remove object from hierarchy and decrement refcount.
* @kobj: object going away.
*/
void kobject_unregister(struct kobject * kobj)
{
if (!kobj)
return;
pr_debug("kobject %s: unregistering\n",kobject_name(kobj));
kobject_uevent(kobj, KOBJ_REMOVE);
kobject_del(kobj);
kobject_put(kobj);
}
/**
* 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);
struct kset * s = kobj->kset;
struct kobject * parent = kobj->parent;
const char *name = kobj->k_name;
pr_debug("kobject %s: cleaning up\n",kobject_name(kobj));
if (t && t->release) {
t->release(kobj);
/* If we have a release function, we can guess that this was
* not a statically allocated kobject, so we should be safe to
* free the name */
kfree(name);
}
if (s)
kset_put(s);
kobject_put(parent);
}
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)
kref_put(&kobj->kref, kobject_release);
}
static void dynamic_kobj_release(struct kobject *kobj)
{
pr_debug("%s: freeing %s\n", __FUNCTION__, kobject_name(kobj));
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_ng() 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_ng(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 kset structure dynamically and registers it
* with sysfs. When you are finished with this structure, call
* kobject_unregister() 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_ng(kobj, parent, "%s", name);
if (retval) {
printk(KERN_WARNING "%s: kobject_add error: %d\n",
__FUNCTION__, 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(&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_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)
{
int err;
if (!k)
return -EINVAL;
kset_init(k);
err = kset_add(k);
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_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;
}
static void kset_release(struct kobject *kobj)
{
struct kset *kset = container_of(kobj, struct kset, kobj);
pr_debug("kset %s: now freed\n", kobject_name(kobj));
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_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);
