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/*
* fs/sysfs/dir.c - sysfs core and dir operation implementation
*
* Copyright (c) 2001-3 Patrick Mochel
* Copyright (c) 2007 SUSE Linux Products GmbH
* Copyright (c) 2007 Tejun Heo <teheo@suse.de>
*
* This file is released under the GPLv2.
*
* Please see Documentation/filesystems/sysfs.txt for more information.
*/
#undef DEBUG
#include <linux/fs.h>
#include <linux/kobject.h>
#include <linux/slab.h>
#include "sysfs.h"
DEFINE_SPINLOCK(sysfs_symlink_target_lock);
/**
* sysfs_pathname - return full path to sysfs dirent
* @sd: sysfs_dirent whose path we want
* @path: caller allocated buffer of size PATH_MAX
*
* Gives the name "/" to the sysfs_root entry; any path returned
* is relative to wherever sysfs is mounted.
*/
static char *sysfs_pathname(struct sysfs_dirent *sd, char *path)
{
if (sd->s_parent) {
sysfs_pathname(sd->s_parent, path);
strlcat(path, "/", PATH_MAX);
}
strlcat(path, sd->s_name, PATH_MAX);
return path;
}
void sysfs_warn_dup(struct sysfs_dirent *parent, const char *name)
{
char *path;
path = kzalloc(PATH_MAX, GFP_KERNEL);
if (path) {
sysfs_pathname(parent, path);
strlcat(path, "/", PATH_MAX);
strlcat(path, name, PATH_MAX);
}
WARN(1, KERN_WARNING "sysfs: cannot create duplicate filename '%s'\n",
path ? path : name);
kfree(path);
}
/**
* sysfs_create_dir_ns - create a directory for an object with a namespace tag
* @kobj: object we're creating directory for
* @ns: the namespace tag to use
*/
int sysfs_create_dir_ns(struct kobject *kobj, const void *ns)
{
struct sysfs_dirent *parent_sd, *sd;
BUG_ON(!kobj);
if (kobj->parent)
parent_sd = kobj->parent->sd;
else
parent_sd = sysfs_root_sd;
if (!parent_sd)
return -ENOENT;
sd = kernfs_create_dir_ns(parent_sd, kobject_name(kobj), kobj, ns);
if (IS_ERR(sd)) {
if (PTR_ERR(sd) == -EEXIST)
sysfs_warn_dup(parent_sd, kobject_name(kobj));
return PTR_ERR(sd);
}
kobj->sd = sd;
return 0;
}
/**
* sysfs_remove_dir - remove an object's directory.
* @kobj: object.
*
* The only thing special about this is that we remove any files in
* the directory before we remove the directory, and we've inlined
* what used to be sysfs_rmdir() below, instead of calling separately.
*/
void sysfs_remove_dir(struct kobject *kobj)
{
struct sysfs_dirent *sd = kobj->sd;
/*
* In general, kboject owner is responsible for ensuring removal
* doesn't race with other operations and sysfs doesn't provide any
* protection; however, when @kobj is used as a symlink target, the
* symlinking entity usually doesn't own @kobj and thus has no
* control over removal. @kobj->sd may be removed anytime and
* symlink code may end up dereferencing an already freed sd.
*
* sysfs_symlink_target_lock synchronizes @kobj->sd disassociation
* against symlink operations so that symlink code can safely
* dereference @kobj->sd.
*/
spin_lock(&sysfs_symlink_target_lock);
kobj->sd = NULL;
spin_unlock(&sysfs_symlink_target_lock);
if (sd) {
WARN_ON_ONCE(sysfs_type(sd) != SYSFS_DIR);
kernfs_remove(sd);
}
}
int sysfs_rename_dir_ns(struct kobject *kobj, const char *new_name,
const void *new_ns)
{
struct sysfs_dirent *parent_sd = kobj->sd->s_parent;
return kernfs_rename_ns(kobj->sd, parent_sd, new_name, new_ns);
}
int sysfs_move_dir_ns(struct kobject *kobj, struct kobject *new_parent_kobj,
const void *new_ns)
{
struct sysfs_dirent *sd = kobj->sd;
struct sysfs_dirent *new_parent_sd;
BUG_ON(!sd->s_parent);
new_parent_sd = new_parent_kobj && new_parent_kobj->sd ?
new_parent_kobj->sd : sysfs_root_sd;
return kernfs_rename_ns(sd, new_parent_sd, sd->s_name, new_ns);
}
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