kernel_optimize_test/lib/kobject.c
Eric W. Biederman 030c1d2bfc kobject: Fix kobject_rename and !CONFIG_SYSFS
When looking at kobject_rename I found two bugs with
that exist when sysfs support is disabled in the kernel.

kobject_rename does not change the name on the kobject when
sysfs support is not compiled in.

kobject_rename without locking attempts to check the
validity of a rename operation, which the kobject layer
simply does not have the infrastructure to do.

This patch documents the previously unstated requirement of
kobject_rename that is the responsibility of the caller to
provide mutual exclusion and to be certain that the new_name
for the kobject is valid.

This patch modifies sysfs_rename_dir in !CONFIG_SYSFS case
to call kobject_set_name to actually change the kobject_name.

This patch removes the bogus and misleading check in kobject_rename
that attempts to see if a rename is valid.  The check is bogus
because we do not have the proper locking.  The check is misleading
because it looks like we can and do perform checking at the kobject
level that we don't.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-10-16 09:24:52 -07:00

838 lines
20 KiB
C

/*
* 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++) {
error = sysfs_create_file(kobj, attr);
if (error)
break;
}
}
return error;
}
static int create_dir(struct kobject *kobj)
{
int error = 0;
if (kobject_name(kobj)) {
error = sysfs_create_dir(kobj);
if (!error) {
error = populate_dir(kobj);
if (error)
sysfs_remove_dir(kobj);
}
}
return error;
}
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("kobject: '%s' (%p): %s: path = '%s'\n", kobject_name(kobj),
kobj, __func__, 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);
/* add the kobject to its kset's list */
static void kobj_kset_join(struct kobject *kobj)
{
if (!kobj->kset)
return;
kset_get(kobj->kset);
spin_lock(&kobj->kset->list_lock);
list_add_tail(&kobj->entry, &kobj->kset->list);
spin_unlock(&kobj->kset->list_lock);
}
/* remove the kobject from its kset's list */
static void kobj_kset_leave(struct kobject *kobj)
{
if (!kobj->kset)
return;
spin_lock(&kobj->kset->list_lock);
list_del_init(&kobj->entry);
spin_unlock(&kobj->kset->list_lock);
kset_put(kobj->kset);
}
static void kobject_init_internal(struct kobject *kobj)
{
if (!kobj)
return;
kref_init(&kobj->kref);
INIT_LIST_HEAD(&kobj->entry);
kobj->state_in_sysfs = 0;
kobj->state_add_uevent_sent = 0;
kobj->state_remove_uevent_sent = 0;
kobj->state_initialized = 1;
}
static int kobject_add_internal(struct kobject *kobj)
{
int error = 0;
struct kobject *parent;
if (!kobj)
return -ENOENT;
if (!kobj->name || !kobj->name[0]) {
WARN(1, "kobject: (%p): attempted to be registered with empty "
"name!\n", kobj);
return -EINVAL;
}
parent = kobject_get(kobj->parent);
/* join kset if set, use it as parent if we do not already have one */
if (kobj->kset) {
if (!parent)
parent = kobject_get(&kobj->kset->kobj);
kobj_kset_join(kobj);
kobj->parent = parent;
}
pr_debug("kobject: '%s' (%p): %s: parent: '%s', set: '%s'\n",
kobject_name(kobj), kobj, __func__,
parent ? kobject_name(parent) : "<NULL>",
kobj->kset ? kobject_name(&kobj->kset->kobj) : "<NULL>");
error = create_dir(kobj);
if (error) {
kobj_kset_leave(kobj);
kobject_put(parent);
kobj->parent = NULL;
/* be noisy on error issues */
if (error == -EEXIST)
printk(KERN_ERR "%s failed for %s with "
"-EEXIST, don't try to register things with "
"the same name in the same directory.\n",
__func__, kobject_name(kobj));
else
printk(KERN_ERR "%s failed for %s (%d)\n",
__func__, kobject_name(kobj), error);
dump_stack();
} else
kobj->state_in_sysfs = 1;
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)
{
const char *old_name = kobj->name;
char *s;
kobj->name = kvasprintf(GFP_KERNEL, fmt, vargs);
if (!kobj->name)
return -ENOMEM;
/* ewww... some of these buggers have '/' in the name ... */
while ((s = strchr(kobj->name, '/')))
s[0] = '!';
kfree(old_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 vargs;
int retval;
va_start(vargs, fmt);
retval = kobject_set_name_vargs(kobj, fmt, vargs);
va_end(vargs);
return retval;
}
EXPORT_SYMBOL(kobject_set_name);
/**
* kobject_init - 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(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 (kobj->state_initialized) {
/* do not error out as sometimes we can recover */
printk(KERN_ERR "kobject (%p): tried to init an initialized "
"object, something is seriously wrong.\n", kobj);
dump_stack();
}
kobject_init_internal(kobj);
kobj->ktype = ktype;
return;
error:
printk(KERN_ERR "kobject (%p): %s\n", kobj, err_str);
dump_stack();
}
EXPORT_SYMBOL(kobject_init);
static int kobject_add_varg(struct kobject *kobj, struct kobject *parent,
const char *fmt, va_list vargs)
{
int retval;
retval = kobject_set_name_vargs(kobj, fmt, vargs);
if (retval) {
printk(KERN_ERR "kobject: can not set name properly!\n");
return retval;
}
kobj->parent = parent;
return kobject_add_internal(kobj);
}
/**
* kobject_add - 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.
* 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 "add" 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(struct kobject *kobj, struct kobject *parent,
const char *fmt, ...)
{
va_list args;
int retval;
if (!kobj)
return -EINVAL;
if (!kobj->state_initialized) {
printk(KERN_ERR "kobject '%s' (%p): tried to add an "
"uninitialized object, something is seriously wrong.\n",
kobject_name(kobj), kobj);
dump_stack();
return -EINVAL;
}
va_start(args, fmt);
retval = kobject_add_varg(kobj, parent, fmt, args);
va_end(args);
return retval;
}
EXPORT_SYMBOL(kobject_add);
/**
* 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() and
* kobject_add(). The same type of error handling after a call to
* kobject_add() 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(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
*
* It is the responsibility of the caller to provide mutual
* exclusion between two different calls of kobject_rename
* on the same kobject and to ensure that new_name is valid and
* won't conflict with other kobjects.
*/
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;
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;
}
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);