/*
* 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/mount.h>
#include <linux/module.h>
#include <linux/kobject.h>
#include <linux/namei.h>
#include <linux/idr.h>
#include <linux/completion.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/security.h>
#include <linux/hash.h>
#include "sysfs.h"
DEFINE_MUTEX(sysfs_mutex);
DEFINE_SPINLOCK(sysfs_assoc_lock);
#define to_sysfs_dirent(X) rb_entry((X), struct sysfs_dirent, s_rb);
static DEFINE_SPINLOCK(sysfs_ino_lock);
static DEFINE_IDA(sysfs_ino_ida);
/**
* sysfs_name_hash
* @ns: Namespace tag to hash
* @name: Null terminated string to hash
*
* Returns 31 bit hash of ns + name (so it fits in an off_t )
*/
static unsigned int sysfs_name_hash(const void *ns, const char *name)
{
unsigned long hash = init_name_hash();
unsigned int len = strlen(name);
while (len--)
hash = partial_name_hash(*name++, hash);
hash = ( end_name_hash(hash) ^ hash_ptr( (void *)ns, 31 ) );
hash &= 0x7fffffffU;
/* Reserve hash numbers 0, 1 and INT_MAX for magic directory entries */
if (hash < 1)
hash += 2;
if (hash >= INT_MAX)
hash = INT_MAX - 1;
return hash;
}
static int sysfs_name_compare(unsigned int hash, const void *ns,
const char *name, const struct sysfs_dirent *sd)
{
if (hash != sd->s_hash)
return hash - sd->s_hash;
if (ns != sd->s_ns)
return ns - sd->s_ns;
return strcmp(name, sd->s_name);
}
static int sysfs_sd_compare(const struct sysfs_dirent *left,
const struct sysfs_dirent *right)
{
return sysfs_name_compare(left->s_hash, left->s_ns, left->s_name,
right);
}
/**
* sysfs_link_subling - link sysfs_dirent into sibling rbtree
* @sd: sysfs_dirent of interest
*
* Link @sd into its sibling rbtree which starts from
* sd->s_parent->s_dir.children.
*
* Locking:
* mutex_lock(sysfs_mutex)
*
* RETURNS:
* 0 on susccess -EEXIST on failure.
*/
static int sysfs_link_sibling(struct sysfs_dirent *sd)
{
struct rb_node **node = &sd->s_parent->s_dir.children.rb_node;
struct rb_node *parent = NULL;
if (sysfs_type(sd) == SYSFS_DIR)
sd->s_parent->s_dir.subdirs++;
while (*node) {
struct sysfs_dirent *pos;
int result;
pos = to_sysfs_dirent(*node);
parent = *node;
result = sysfs_sd_compare(sd, pos);
if (result < 0)
node = &pos->s_rb.rb_left;
else if (result > 0)
node = &pos->s_rb.rb_right;
else
return -EEXIST;
}
/* add new node and rebalance the tree */
rb_link_node(&sd->s_rb, parent, node);
rb_insert_color(&sd->s_rb, &sd->s_parent->s_dir.children);
return 0;
}
/**
* sysfs_unlink_sibling - unlink sysfs_dirent from sibling rbtree
* @sd: sysfs_dirent of interest
*
* Unlink @sd from its sibling rbtree which starts from
* sd->s_parent->s_dir.children.
*
* Locking:
* mutex_lock(sysfs_mutex)
*/
static void sysfs_unlink_sibling(struct sysfs_dirent *sd)
{
if (sysfs_type(sd) == SYSFS_DIR)
sd->s_parent->s_dir.subdirs--;
rb_erase(&sd->s_rb, &sd->s_parent->s_dir.children);
}
/**
* sysfs_get_active - get an active reference to sysfs_dirent
* @sd: sysfs_dirent to get an active reference to
*
* Get an active reference of @sd. This function is noop if @sd
* is NULL.
*
* RETURNS:
* Pointer to @sd on success, NULL on failure.
*/
struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd)
{
if (unlikely(!sd))
return NULL;
while (1) {
int v, t;
v = atomic_read(&sd->s_active);
if (unlikely(v < 0))
return NULL;
t = atomic_cmpxchg(&sd->s_active, v, v + 1);
if (likely(t == v)) {
rwsem_acquire_read(&sd->dep_map, 0, 1, _RET_IP_);
return sd;
}
if (t < 0)
return NULL;
cpu_relax();
}
}
/**
* sysfs_put_active - put an active reference to sysfs_dirent
* @sd: sysfs_dirent to put an active reference to
*
* Put an active reference to @sd. This function is noop if @sd
* is NULL.
*/
void sysfs_put_active(struct sysfs_dirent *sd)
{
int v;
if (unlikely(!sd))
return;
rwsem_release(&sd->dep_map, 1, _RET_IP_);
v = atomic_dec_return(&sd->s_active);
if (likely(v != SD_DEACTIVATED_BIAS))
return;
/* atomic_dec_return() is a mb(), we'll always see the updated
* sd->u.completion.
*/
complete(sd->u.completion);
}
/**
* sysfs_deactivate - deactivate sysfs_dirent
* @sd: sysfs_dirent to deactivate
*
* Deny new active references and drain existing ones.
*/
static void sysfs_deactivate(struct sysfs_dirent *sd)
{
DECLARE_COMPLETION_ONSTACK(wait);
int v;
BUG_ON(!(sd->s_flags & SYSFS_FLAG_REMOVED));
if (!(sysfs_type(sd) & SYSFS_ACTIVE_REF))
return;
sd->u.completion = (void *)&wait;
rwsem_acquire(&sd->dep_map, 0, 0, _RET_IP_);
/* atomic_add_return() is a mb(), put_active() will always see
* the updated sd->u.completion.
*/
v = atomic_add_return(SD_DEACTIVATED_BIAS, &sd->s_active);
if (v != SD_DEACTIVATED_BIAS) {
lock_contended(&sd->dep_map, _RET_IP_);
wait_for_completion(&wait);
}
lock_acquired(&sd->dep_map, _RET_IP_);
rwsem_release(&sd->dep_map, 1, _RET_IP_);
}
static int sysfs_alloc_ino(ino_t *pino)
{
int ino, rc;
retry:
spin_lock(&sysfs_ino_lock);
rc = ida_get_new_above(&sysfs_ino_ida, 2, &ino);
spin_unlock(&sysfs_ino_lock);
if (rc == -EAGAIN) {
if (ida_pre_get(&sysfs_ino_ida, GFP_KERNEL))
goto retry;
rc = -ENOMEM;
}
*pino = ino;
return rc;
}
static void sysfs_free_ino(ino_t ino)
{
spin_lock(&sysfs_ino_lock);
ida_remove(&sysfs_ino_ida, ino);
spin_unlock(&sysfs_ino_lock);
}
void release_sysfs_dirent(struct sysfs_dirent * sd)
{
struct sysfs_dirent *parent_sd;
repeat:
/* Moving/renaming is always done while holding reference.
* sd->s_parent won't change beneath us.
*/
parent_sd = sd->s_parent;
if (sysfs_type(sd) == SYSFS_KOBJ_LINK)
sysfs_put(sd->s_symlink.target_sd);
if (sysfs_type(sd) & SYSFS_COPY_NAME)
kfree(sd->s_name);
if (sd->s_iattr && sd->s_iattr->ia_secdata)
security_release_secctx(sd->s_iattr->ia_secdata,
sd->s_iattr->ia_secdata_len);
kfree(sd->s_iattr);
sysfs_free_ino(sd->s_ino);
kmem_cache_free(sysfs_dir_cachep, sd);
sd = parent_sd;
if (sd && atomic_dec_and_test(&sd->s_count))
goto repeat;
}
static int sysfs_dentry_delete(const struct dentry *dentry)
{
struct sysfs_dirent *sd = dentry->d_fsdata;
return !!(sd->s_flags & SYSFS_FLAG_REMOVED);
}
static int sysfs_dentry_revalidate(struct dentry *dentry, struct nameidata *nd)
{
struct sysfs_dirent *sd;
int is_dir;
if (nd->flags & LOOKUP_RCU)
return -ECHILD;
sd = dentry->d_fsdata;
mutex_lock(&sysfs_mutex);
/* The sysfs dirent has been deleted */
if (sd->s_flags & SYSFS_FLAG_REMOVED)
goto out_bad;
/* The sysfs dirent has been moved? */
if (dentry->d_parent->d_fsdata != sd->s_parent)
goto out_bad;
/* The sysfs dirent has been renamed */
if (strcmp(dentry->d_name.name, sd->s_name) != 0)
goto out_bad;
mutex_unlock(&sysfs_mutex);
out_valid:
return 1;
out_bad:
/* Remove the dentry from the dcache hashes.
* If this is a deleted dentry we use d_drop instead of d_delete
* so sysfs doesn't need to cope with negative dentries.
*
* If this is a dentry that has simply been renamed we
* use d_drop to remove it from the dcache lookup on its
* old parent. If this dentry persists later when a lookup
* is performed at its new name the dentry will be readded
* to the dcache hashes.
*/
is_dir = (sysfs_type(sd) == SYSFS_DIR);
mutex_unlock(&sysfs_mutex);
if (is_dir) {
/* If we have submounts we must allow the vfs caches
* to lie about the state of the filesystem to prevent
* leaks and other nasty things.
*/
if (have_submounts(dentry))
goto out_valid;
shrink_dcache_parent(dentry);
}
d_drop(dentry);
return 0;
}
static void sysfs_dentry_iput(struct dentry *dentry, struct inode *inode)
{
struct sysfs_dirent * sd = dentry->d_fsdata;
sysfs_put(sd);
iput(inode);
}
static const struct dentry_operations sysfs_dentry_ops = {
.d_revalidate = sysfs_dentry_revalidate,
.d_delete = sysfs_dentry_delete,
.d_iput = sysfs_dentry_iput,
};
struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type)
{
char *dup_name = NULL;
struct sysfs_dirent *sd;
if (type & SYSFS_COPY_NAME) {
name = dup_name = kstrdup(name, GFP_KERNEL);
if (!name)
return NULL;
}
sd = kmem_cache_zalloc(sysfs_dir_cachep, GFP_KERNEL);
if (!sd)
goto err_out1;
if (sysfs_alloc_ino(&sd->s_ino))
goto err_out2;
atomic_set(&sd->s_count, 1);
atomic_set(&sd->s_active, 0);
sd->s_name = name;
sd->s_mode = mode;
sd->s_flags = type;
return sd;
err_out2:
kmem_cache_free(sysfs_dir_cachep, sd);
err_out1:
kfree(dup_name);
return NULL;
}
/**
* sysfs_addrm_start - prepare for sysfs_dirent add/remove
* @acxt: pointer to sysfs_addrm_cxt to be used
* @parent_sd: parent sysfs_dirent
*
* This function is called when the caller is about to add or
* remove sysfs_dirent under @parent_sd. This function acquires
* sysfs_mutex. @acxt is used to keep and pass context to
* other addrm functions.
*
* LOCKING:
* Kernel thread context (may sleep). sysfs_mutex is locked on
* return.
*/
void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt,
struct sysfs_dirent *parent_sd)
{
memset(acxt, 0, sizeof(*acxt));
acxt->parent_sd = parent_sd;
mutex_lock(&sysfs_mutex);
}
/**
* __sysfs_add_one - add sysfs_dirent to parent without warning
* @acxt: addrm context to use
* @sd: sysfs_dirent to be added
*
* Get @acxt->parent_sd and set sd->s_parent to it and increment
* nlink of parent inode if @sd is a directory and link into the
* children list of the parent.
*
* This function should be called between calls to
* sysfs_addrm_start() and sysfs_addrm_finish() and should be
* passed the same @acxt as passed to sysfs_addrm_start().
*
* LOCKING:
* Determined by sysfs_addrm_start().
*
* RETURNS:
* 0 on success, -EEXIST if entry with the given name already
* exists.
*/
int __sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
{
struct sysfs_inode_attrs *ps_iattr;
int ret;
if (!!sysfs_ns_type(acxt->parent_sd) != !!sd->s_ns) {
WARN(1, KERN_WARNING "sysfs: ns %s in '%s' for '%s'\n",
sysfs_ns_type(acxt->parent_sd)? "required": "invalid",
acxt->parent_sd->s_name, sd->s_name);
return -EINVAL;
}
sd->s_hash = sysfs_name_hash(sd->s_ns, sd->s_name);
sd->s_parent = sysfs_get(acxt->parent_sd);
ret = sysfs_link_sibling(sd);
if (ret)
return ret;
/* Update timestamps on the parent */
ps_iattr = acxt->parent_sd->s_iattr;
if (ps_iattr) {
struct iattr *ps_iattrs = &ps_iattr->ia_iattr;
ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME;
}
return 0;
}
/**
* sysfs_pathname - return full path to sysfs dirent
* @sd: sysfs_dirent whose path we want
* @path: caller allocated buffer
*
* Gives the name "/" to the sysfs_root entry; any path returned
* is relative to wherever sysfs is mounted.
*
* XXX: does no error checking on @path size
*/
static char *sysfs_pathname(struct sysfs_dirent *sd, char *path)
{
if (sd->s_parent) {
sysfs_pathname(sd->s_parent, path);
strcat(path, "/");
}
strcat(path, sd->s_name);
return path;
}
/**
* sysfs_add_one - add sysfs_dirent to parent
* @acxt: addrm context to use
* @sd: sysfs_dirent to be added
*
* Get @acxt->parent_sd and set sd->s_parent to it and increment
* nlink of parent inode if @sd is a directory and link into the
* children list of the parent.
*
* This function should be called between calls to
* sysfs_addrm_start() and sysfs_addrm_finish() and should be
* passed the same @acxt as passed to sysfs_addrm_start().
*
* LOCKING:
* Determined by sysfs_addrm_start().
*
* RETURNS:
* 0 on success, -EEXIST if entry with the given name already
* exists.
*/
int sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
{
int ret;
ret = __sysfs_add_one(acxt, sd);
if (ret == -EEXIST) {
char *path = kzalloc(PATH_MAX, GFP_KERNEL);
WARN(1, KERN_WARNING
"sysfs: cannot create duplicate filename '%s'\n",
(path == NULL) ? sd->s_name :
strcat(strcat(sysfs_pathname(acxt->parent_sd, path), "/"),
sd->s_name));
kfree(path);
}
return ret;
}
/**
* sysfs_remove_one - remove sysfs_dirent from parent
* @acxt: addrm context to use
* @sd: sysfs_dirent to be removed
*
* Mark @sd removed and drop nlink of parent inode if @sd is a
* directory. @sd is unlinked from the children list.
*
* This function should be called between calls to
* sysfs_addrm_start() and sysfs_addrm_finish() and should be
* passed the same @acxt as passed to sysfs_addrm_start().
*
* LOCKING:
* Determined by sysfs_addrm_start().
*/
void sysfs_remove_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
{
struct sysfs_inode_attrs *ps_iattr;
BUG_ON(sd->s_flags & SYSFS_FLAG_REMOVED);
sysfs_unlink_sibling(sd);
/* Update timestamps on the parent */
ps_iattr = acxt->parent_sd->s_iattr;
if (ps_iattr) {
struct iattr *ps_iattrs = &ps_iattr->ia_iattr;
ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME;
}
sd->s_flags |= SYSFS_FLAG_REMOVED;
sd->u.removed_list = acxt->removed;
acxt->removed = sd;
}
/**
* sysfs_addrm_finish - finish up sysfs_dirent add/remove
* @acxt: addrm context to finish up
*
* Finish up sysfs_dirent add/remove. Resources acquired by
* sysfs_addrm_start() are released and removed sysfs_dirents are
* cleaned up.
*
* LOCKING:
* sysfs_mutex is released.
*/
void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt)
{
/* release resources acquired by sysfs_addrm_start() */
mutex_unlock(&sysfs_mutex);
/* kill removed sysfs_dirents */
while (acxt->removed) {
struct sysfs_dirent *sd = acxt->removed;
acxt->removed = sd->u.removed_list;
sysfs_deactivate(sd);
unmap_bin_file(sd);
sysfs_put(sd);
}
}
/**
* sysfs_find_dirent - find sysfs_dirent with the given name
* @parent_sd: sysfs_dirent to search under
* @name: name to look for
*
* Look for sysfs_dirent with name @name under @parent_sd.
*
* LOCKING:
* mutex_lock(sysfs_mutex)
*
* RETURNS:
* Pointer to sysfs_dirent if found, NULL if not.
*/
struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd,
const void *ns,
const unsigned char *name)
{
struct rb_node *node = parent_sd->s_dir.children.rb_node;
unsigned int hash;
if (!!sysfs_ns_type(parent_sd) != !!ns) {
WARN(1, KERN_WARNING "sysfs: ns %s in '%s' for '%s'\n",
sysfs_ns_type(parent_sd)? "required": "invalid",
parent_sd->s_name, name);
return NULL;
}
hash = sysfs_name_hash(ns, name);
while (node) {
struct sysfs_dirent *sd;
int result;
sd = to_sysfs_dirent(node);
result = sysfs_name_compare(hash, ns, name, sd);
if (result < 0)
node = node->rb_left;
else if (result > 0)
node = node->rb_right;
else
return sd;
}
return NULL;
}
/**
* sysfs_get_dirent - find and get sysfs_dirent with the given name
* @parent_sd: sysfs_dirent to search under
* @name: name to look for
*
* Look for sysfs_dirent with name @name under @parent_sd and get
* it if found.
*
* LOCKING:
* Kernel thread context (may sleep). Grabs sysfs_mutex.
*
* RETURNS:
* Pointer to sysfs_dirent if found, NULL if not.
*/
struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd,
const void *ns,
const unsigned char *name)
{
struct sysfs_dirent *sd;
mutex_lock(&sysfs_mutex);
sd = sysfs_find_dirent(parent_sd, ns, name);
sysfs_get(sd);
mutex_unlock(&sysfs_mutex);
return sd;
}
EXPORT_SYMBOL_GPL(sysfs_get_dirent);
static int create_dir(struct kobject *kobj, struct sysfs_dirent *parent_sd,
enum kobj_ns_type type, const void *ns, const char *name,
struct sysfs_dirent **p_sd)
{
umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO;
struct sysfs_addrm_cxt acxt;
struct sysfs_dirent *sd;
int rc;
/* allocate */
sd = sysfs_new_dirent(name, mode, SYSFS_DIR);
if (!sd)
return -ENOMEM;
sd->s_flags |= (type << SYSFS_NS_TYPE_SHIFT);
sd->s_ns = ns;
sd->s_dir.kobj = kobj;
/* link in */
sysfs_addrm_start(&acxt, parent_sd);
rc = sysfs_add_one(&acxt, sd);
sysfs_addrm_finish(&acxt);
if (rc == 0)
*p_sd = sd;
else
sysfs_put(sd);
return rc;
}
int sysfs_create_subdir(struct kobject *kobj, const char *name,
struct sysfs_dirent **p_sd)
{
return create_dir(kobj, kobj->sd,
KOBJ_NS_TYPE_NONE, NULL, name, p_sd);
}
/**
* sysfs_read_ns_type: return associated ns_type
* @kobj: the kobject being queried
*
* Each kobject can be tagged with exactly one namespace type
* (i.e. network or user). Return the ns_type associated with
* this object if any
*/
static enum kobj_ns_type sysfs_read_ns_type(struct kobject *kobj)
{
const struct kobj_ns_type_operations *ops;
enum kobj_ns_type type;
ops = kobj_child_ns_ops(kobj);
if (!ops)
return KOBJ_NS_TYPE_NONE;
type = ops->type;
BUG_ON(type <= KOBJ_NS_TYPE_NONE);
BUG_ON(type >= KOBJ_NS_TYPES);
BUG_ON(!kobj_ns_type_registered(type));
return type;
}
/**
* sysfs_create_dir - create a directory for an object.
* @kobj: object we're creating directory for.
*/
int sysfs_create_dir(struct kobject * kobj)
{
enum kobj_ns_type type;
struct sysfs_dirent *parent_sd, *sd;
const void *ns = NULL;
int error = 0;
BUG_ON(!kobj);
if (kobj->parent)
parent_sd = kobj->parent->sd;
else
parent_sd = &sysfs_root;
if (sysfs_ns_type(parent_sd))
ns = kobj->ktype->namespace(kobj);
type = sysfs_read_ns_type(kobj);
error = create_dir(kobj, parent_sd, type, ns, kobject_name(kobj), &sd);
if (!error)
kobj->sd = sd;
return error;
}
static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry,
struct nameidata *nd)
{
struct dentry *ret = NULL;
struct dentry *parent = dentry->d_parent;
struct sysfs_dirent *parent_sd = parent->d_fsdata;
struct sysfs_dirent *sd;
struct inode *inode;
enum kobj_ns_type type;
const void *ns;
mutex_lock(&sysfs_mutex);
type = sysfs_ns_type(parent_sd);
ns = sysfs_info(dir->i_sb)->ns[type];
sd = sysfs_find_dirent(parent_sd, ns, dentry->d_name.name);
/* no such entry */
if (!sd) {
ret = ERR_PTR(-ENOENT);
goto out_unlock;
}
/* attach dentry and inode */
inode = sysfs_get_inode(dir->i_sb, sd);
if (!inode) {
ret = ERR_PTR(-ENOMEM);
goto out_unlock;
}
/* instantiate and hash dentry */
ret = d_find_alias(inode);
if (!ret) {
d_set_d_op(dentry, &sysfs_dentry_ops);
dentry->d_fsdata = sysfs_get(sd);
d_add(dentry, inode);
} else {
d_move(ret, dentry);
iput(inode);
}
out_unlock:
mutex_unlock(&sysfs_mutex);
return ret;
}
const struct inode_operations sysfs_dir_inode_operations = {
.lookup = sysfs_lookup,
.permission = sysfs_permission,
.setattr = sysfs_setattr,
.getattr = sysfs_getattr,
.setxattr = sysfs_setxattr,
};
static void remove_dir(struct sysfs_dirent *sd)
{
struct sysfs_addrm_cxt acxt;
sysfs_addrm_start(&acxt, sd->s_parent);
sysfs_remove_one(&acxt, sd);
sysfs_addrm_finish(&acxt);
}
void sysfs_remove_subdir(struct sysfs_dirent *sd)
{
remove_dir(sd);
}
static void __sysfs_remove_dir(struct sysfs_dirent *dir_sd)
{
struct sysfs_addrm_cxt acxt;
struct rb_node *pos;
if (!dir_sd)
return;
pr_debug("sysfs %s: removing dir\n", dir_sd->s_name);
sysfs_addrm_start(&acxt, dir_sd);
pos = rb_first(&dir_sd->s_dir.children);
while (pos) {
struct sysfs_dirent *sd = to_sysfs_dirent(pos);
pos = rb_next(pos);
if (sysfs_type(sd) != SYSFS_DIR)
sysfs_remove_one(&acxt, sd);
}
sysfs_addrm_finish(&acxt);
remove_dir(dir_sd);
}
/**
* 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;
spin_lock(&sysfs_assoc_lock);
kobj->sd = NULL;
spin_unlock(&sysfs_assoc_lock);
__sysfs_remove_dir(sd);
}
int sysfs_rename(struct sysfs_dirent *sd,
struct sysfs_dirent *new_parent_sd, const void *new_ns,
const char *new_name)
{
const char *dup_name = NULL;
int error;
mutex_lock(&sysfs_mutex);
error = 0;
if ((sd->s_parent == new_parent_sd) && (sd->s_ns == new_ns) &&
(strcmp(sd->s_name, new_name) == 0))
goto out; /* nothing to rename */
error = -EEXIST;
if (sysfs_find_dirent(new_parent_sd, new_ns, new_name))
goto out;
/* rename sysfs_dirent */
if (strcmp(sd->s_name, new_name) != 0) {
error = -ENOMEM;
new_name = dup_name = kstrdup(new_name, GFP_KERNEL);
if (!new_name)
goto out;
dup_name = sd->s_name;
sd->s_name = new_name;
}
/* Move to the appropriate place in the appropriate directories rbtree. */
sysfs_unlink_sibling(sd);
sysfs_get(new_parent_sd);
sysfs_put(sd->s_parent);
sd->s_ns = new_ns;
sd->s_parent = new_parent_sd;
sysfs_link_sibling(sd);
error = 0;
out:
mutex_unlock(&sysfs_mutex);
kfree(dup_name);
return error;
}
int sysfs_rename_dir(struct kobject *kobj, const char *new_name)
{
struct sysfs_dirent *parent_sd = kobj->sd->s_parent;
const void *new_ns = NULL;
if (sysfs_ns_type(parent_sd))
new_ns = kobj->ktype->namespace(kobj);
return sysfs_rename(kobj->sd, parent_sd, new_ns, new_name);
}
int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent_kobj)
{
struct sysfs_dirent *sd = kobj->sd;
struct sysfs_dirent *new_parent_sd;
const void *new_ns = NULL;
BUG_ON(!sd->s_parent);
if (sysfs_ns_type(sd->s_parent))
new_ns = kobj->ktype->namespace(kobj);
new_parent_sd = new_parent_kobj && new_parent_kobj->sd ?
new_parent_kobj->sd : &sysfs_root;
return sysfs_rename(sd, new_parent_sd, new_ns, sd->s_name);
}
/* Relationship between s_mode and the DT_xxx types */
static inline unsigned char dt_type(struct sysfs_dirent *sd)
{
return (sd->s_mode >> 12) & 15;
}
static int sysfs_dir_release(struct inode *inode, struct file *filp)
{
sysfs_put(filp->private_data);
return 0;
}
static struct sysfs_dirent *sysfs_dir_pos(const void *ns,
struct sysfs_dirent *parent_sd, loff_t hash, struct sysfs_dirent *pos)
{
if (pos) {
int valid = !(pos->s_flags & SYSFS_FLAG_REMOVED) &&
pos->s_parent == parent_sd &&
hash == pos->s_hash;
sysfs_put(pos);
if (!valid)
pos = NULL;
}
if (!pos && (hash > 1) && (hash < INT_MAX)) {
struct rb_node *node = parent_sd->s_dir.children.rb_node;
while (node) {
pos = to_sysfs_dirent(node);
if (hash < pos->s_hash)
node = node->rb_left;
else if (hash > pos->s_hash)
node = node->rb_right;
else
break;
}
}
/* Skip over entries in the wrong namespace */
while (pos && pos->s_ns != ns) {
struct rb_node *node = rb_next(&pos->s_rb);
if (!node)
pos = NULL;
else
pos = to_sysfs_dirent(node);
}
return pos;
}
static struct sysfs_dirent *sysfs_dir_next_pos(const void *ns,
struct sysfs_dirent *parent_sd, ino_t ino, struct sysfs_dirent *pos)
{
pos = sysfs_dir_pos(ns, parent_sd, ino, pos);
if (pos) do {
struct rb_node *node = rb_next(&pos->s_rb);
if (!node)
pos = NULL;
else
pos = to_sysfs_dirent(node);
} while (pos && pos->s_ns != ns);
return pos;
}
static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
{
struct dentry *dentry = filp->f_path.dentry;
struct sysfs_dirent * parent_sd = dentry->d_fsdata;
struct sysfs_dirent *pos = filp->private_data;
enum kobj_ns_type type;
const void *ns;
ino_t ino;
type = sysfs_ns_type(parent_sd);
ns = sysfs_info(dentry->d_sb)->ns[type];
if (filp->f_pos == 0) {
ino = parent_sd->s_ino;
if (filldir(dirent, ".", 1, filp->f_pos, ino, DT_DIR) == 0)
filp->f_pos++;
}
if (filp->f_pos == 1) {
if (parent_sd->s_parent)
ino = parent_sd->s_parent->s_ino;
else
ino = parent_sd->s_ino;
if (filldir(dirent, "..", 2, filp->f_pos, ino, DT_DIR) == 0)
filp->f_pos++;
}
mutex_lock(&sysfs_mutex);
for (pos = sysfs_dir_pos(ns, parent_sd, filp->f_pos, pos);
pos;
pos = sysfs_dir_next_pos(ns, parent_sd, filp->f_pos, pos)) {
const char * name;
unsigned int type;
int len, ret;
name = pos->s_name;
len = strlen(name);
ino = pos->s_ino;
type = dt_type(pos);
filp->f_pos = pos->s_hash;
filp->private_data = sysfs_get(pos);
mutex_unlock(&sysfs_mutex);
ret = filldir(dirent, name, len, filp->f_pos, ino, type);
mutex_lock(&sysfs_mutex);
if (ret < 0)
break;
}
mutex_unlock(&sysfs_mutex);
if ((filp->f_pos > 1) && !pos) { /* EOF */
filp->f_pos = INT_MAX;
filp->private_data = NULL;
}
return 0;
}
const struct file_operations sysfs_dir_operations = {
.read = generic_read_dir,
.readdir = sysfs_readdir,
.release = sysfs_dir_release,
.llseek = generic_file_llseek,
};
