mirror of
https://github.com/FEX-Emu/linux.git
synced 2024-12-25 19:07:46 +00:00
2322392b02
kernfs inherited "security.*" xattr support from sysfs. This patch extends xattr support to "trusted.*" using simple_xattr_*(). As trusted xattrs are restricted to CAP_SYS_ADMIN, simple_xattr_*() which uses kernel memory for storage shouldn't be problematic. Note that the existing "security.*" support doesn't implement get/remove/list and the this patch only implements those ops for "trusted.*". We probably want to extend those ops to include support for "security.*". This patch will allow using kernfs from cgroup which requires "trusted.*" xattr support. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: David P. Quigley <dpquigl@tycho.nsa.gov> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1021 lines
24 KiB
C
1021 lines
24 KiB
C
/*
|
|
* fs/kernfs/dir.c - kernfs directory implementation
|
|
*
|
|
* Copyright (c) 2001-3 Patrick Mochel
|
|
* Copyright (c) 2007 SUSE Linux Products GmbH
|
|
* Copyright (c) 2007, 2013 Tejun Heo <tj@kernel.org>
|
|
*
|
|
* This file is released under the GPLv2.
|
|
*/
|
|
|
|
#include <linux/fs.h>
|
|
#include <linux/namei.h>
|
|
#include <linux/idr.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/security.h>
|
|
#include <linux/hash.h>
|
|
|
|
#include "kernfs-internal.h"
|
|
|
|
DEFINE_MUTEX(sysfs_mutex);
|
|
|
|
#define to_sysfs_dirent(X) rb_entry((X), struct sysfs_dirent, s_rb)
|
|
|
|
/**
|
|
* sysfs_name_hash
|
|
* @name: Null terminated string to hash
|
|
* @ns: Namespace tag to hash
|
|
*
|
|
* Returns 31 bit hash of ns + name (so it fits in an off_t )
|
|
*/
|
|
static unsigned int sysfs_name_hash(const char *name, const void *ns)
|
|
{
|
|
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 char *name,
|
|
const void *ns, 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_name, left->s_ns,
|
|
right);
|
|
}
|
|
|
|
/**
|
|
* sysfs_link_sibling - 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;
|
|
|
|
if (!atomic_inc_unless_negative(&sd->s_active))
|
|
return NULL;
|
|
|
|
if (sd->s_flags & SYSFS_FLAG_LOCKDEP)
|
|
rwsem_acquire_read(&sd->dep_map, 0, 1, _RET_IP_);
|
|
return sd;
|
|
}
|
|
|
|
/**
|
|
* 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;
|
|
|
|
if (sd->s_flags & SYSFS_FLAG_LOCKDEP)
|
|
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_);
|
|
}
|
|
|
|
/**
|
|
* kernfs_get - get a reference count on a sysfs_dirent
|
|
* @sd: the target sysfs_dirent
|
|
*/
|
|
void kernfs_get(struct sysfs_dirent *sd)
|
|
{
|
|
if (sd) {
|
|
WARN_ON(!atomic_read(&sd->s_count));
|
|
atomic_inc(&sd->s_count);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(kernfs_get);
|
|
|
|
/**
|
|
* kernfs_put - put a reference count on a sysfs_dirent
|
|
* @sd: the target sysfs_dirent
|
|
*
|
|
* Put a reference count of @sd and destroy it if it reached zero.
|
|
*/
|
|
void kernfs_put(struct sysfs_dirent *sd)
|
|
{
|
|
struct sysfs_dirent *parent_sd;
|
|
struct kernfs_root *root;
|
|
|
|
if (!sd || !atomic_dec_and_test(&sd->s_count))
|
|
return;
|
|
root = kernfs_root(sd);
|
|
repeat:
|
|
/* Moving/renaming is always done while holding reference.
|
|
* sd->s_parent won't change beneath us.
|
|
*/
|
|
parent_sd = sd->s_parent;
|
|
|
|
WARN(!(sd->s_flags & SYSFS_FLAG_REMOVED),
|
|
"sysfs: free using entry: %s/%s\n",
|
|
parent_sd ? parent_sd->s_name : "", sd->s_name);
|
|
|
|
if (sysfs_type(sd) == SYSFS_KOBJ_LINK)
|
|
kernfs_put(sd->s_symlink.target_sd);
|
|
if (sysfs_type(sd) & SYSFS_COPY_NAME)
|
|
kfree(sd->s_name);
|
|
if (sd->s_iattr) {
|
|
if (sd->s_iattr->ia_secdata)
|
|
security_release_secctx(sd->s_iattr->ia_secdata,
|
|
sd->s_iattr->ia_secdata_len);
|
|
simple_xattrs_free(&sd->s_iattr->xattrs);
|
|
}
|
|
kfree(sd->s_iattr);
|
|
ida_simple_remove(&root->ino_ida, sd->s_ino);
|
|
kmem_cache_free(sysfs_dir_cachep, sd);
|
|
|
|
sd = parent_sd;
|
|
if (sd) {
|
|
if (atomic_dec_and_test(&sd->s_count))
|
|
goto repeat;
|
|
} else {
|
|
/* just released the root sd, free @root too */
|
|
ida_destroy(&root->ino_ida);
|
|
kfree(root);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(kernfs_put);
|
|
|
|
static int sysfs_dentry_delete(const struct dentry *dentry)
|
|
{
|
|
struct sysfs_dirent *sd = dentry->d_fsdata;
|
|
return !(sd && !(sd->s_flags & SYSFS_FLAG_REMOVED));
|
|
}
|
|
|
|
static int sysfs_dentry_revalidate(struct dentry *dentry, unsigned int flags)
|
|
{
|
|
struct sysfs_dirent *sd;
|
|
|
|
if (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;
|
|
|
|
/* The sysfs dirent has been moved to a different namespace */
|
|
if (sd->s_parent && kernfs_ns_enabled(sd->s_parent) &&
|
|
sysfs_info(dentry->d_sb)->ns != sd->s_ns)
|
|
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.
|
|
*/
|
|
mutex_unlock(&sysfs_mutex);
|
|
|
|
/* 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 (check_submounts_and_drop(dentry) != 0)
|
|
goto out_valid;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void sysfs_dentry_release(struct dentry *dentry)
|
|
{
|
|
kernfs_put(dentry->d_fsdata);
|
|
}
|
|
|
|
const struct dentry_operations sysfs_dentry_ops = {
|
|
.d_revalidate = sysfs_dentry_revalidate,
|
|
.d_delete = sysfs_dentry_delete,
|
|
.d_release = sysfs_dentry_release,
|
|
};
|
|
|
|
struct sysfs_dirent *sysfs_new_dirent(struct kernfs_root *root,
|
|
const char *name, umode_t mode, int type)
|
|
{
|
|
char *dup_name = NULL;
|
|
struct sysfs_dirent *sd;
|
|
int ret;
|
|
|
|
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;
|
|
|
|
ret = ida_simple_get(&root->ino_ida, 1, 0, GFP_KERNEL);
|
|
if (ret < 0)
|
|
goto err_out2;
|
|
sd->s_ino = ret;
|
|
|
|
atomic_set(&sd->s_count, 1);
|
|
atomic_set(&sd->s_active, 0);
|
|
|
|
sd->s_name = name;
|
|
sd->s_mode = mode;
|
|
sd->s_flags = type | SYSFS_FLAG_REMOVED;
|
|
|
|
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
|
|
*
|
|
* This function is called when the caller is about to add or remove
|
|
* sysfs_dirent. 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)
|
|
__acquires(sysfs_mutex)
|
|
{
|
|
memset(acxt, 0, sizeof(*acxt));
|
|
|
|
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
|
|
* @parent_sd: the parent sysfs_dirent to add @sd to
|
|
*
|
|
* Get @parent_sd and set @sd->s_parent to it and increment nlink of
|
|
* the 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_dirent *parent_sd)
|
|
{
|
|
bool has_ns = kernfs_ns_enabled(parent_sd);
|
|
struct sysfs_inode_attrs *ps_iattr;
|
|
int ret;
|
|
|
|
if (has_ns != (bool)sd->s_ns) {
|
|
WARN(1, KERN_WARNING "sysfs: ns %s in '%s' for '%s'\n",
|
|
has_ns ? "required" : "invalid",
|
|
parent_sd->s_name, sd->s_name);
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (sysfs_type(parent_sd) != SYSFS_DIR)
|
|
return -EINVAL;
|
|
|
|
sd->s_hash = sysfs_name_hash(sd->s_name, sd->s_ns);
|
|
sd->s_parent = parent_sd;
|
|
kernfs_get(parent_sd);
|
|
|
|
ret = sysfs_link_sibling(sd);
|
|
if (ret)
|
|
return ret;
|
|
|
|
/* Update timestamps on the parent */
|
|
ps_iattr = 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;
|
|
}
|
|
|
|
/* Mark the entry added into directory tree */
|
|
sd->s_flags &= ~SYSFS_FLAG_REMOVED;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* 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().
|
|
*/
|
|
static void sysfs_remove_one(struct sysfs_addrm_cxt *acxt,
|
|
struct sysfs_dirent *sd)
|
|
{
|
|
struct sysfs_inode_attrs *ps_iattr;
|
|
|
|
/*
|
|
* Removal can be called multiple times on the same node. Only the
|
|
* first invocation is effective and puts the base ref.
|
|
*/
|
|
if (sd->s_flags & SYSFS_FLAG_REMOVED)
|
|
return;
|
|
|
|
if (sd->s_parent) {
|
|
sysfs_unlink_sibling(sd);
|
|
|
|
/* Update timestamps on the parent */
|
|
ps_iattr = sd->s_parent->s_iattr;
|
|
if (ps_iattr) {
|
|
ps_iattr->ia_iattr.ia_ctime = CURRENT_TIME;
|
|
ps_iattr->ia_iattr.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)
|
|
__releases(sysfs_mutex)
|
|
{
|
|
/* 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);
|
|
sysfs_unmap_bin_file(sd);
|
|
kernfs_put(sd);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* kernfs_find_ns - find sysfs_dirent with the given name
|
|
* @parent: sysfs_dirent to search under
|
|
* @name: name to look for
|
|
* @ns: the namespace tag to use
|
|
*
|
|
* Look for sysfs_dirent with name @name under @parent. Returns pointer to
|
|
* the found sysfs_dirent on success, %NULL on failure.
|
|
*/
|
|
static struct sysfs_dirent *kernfs_find_ns(struct sysfs_dirent *parent,
|
|
const unsigned char *name,
|
|
const void *ns)
|
|
{
|
|
struct rb_node *node = parent->s_dir.children.rb_node;
|
|
bool has_ns = kernfs_ns_enabled(parent);
|
|
unsigned int hash;
|
|
|
|
lockdep_assert_held(&sysfs_mutex);
|
|
|
|
if (has_ns != (bool)ns) {
|
|
WARN(1, KERN_WARNING "sysfs: ns %s in '%s' for '%s'\n",
|
|
has_ns ? "required" : "invalid",
|
|
parent->s_name, name);
|
|
return NULL;
|
|
}
|
|
|
|
hash = sysfs_name_hash(name, ns);
|
|
while (node) {
|
|
struct sysfs_dirent *sd;
|
|
int result;
|
|
|
|
sd = to_sysfs_dirent(node);
|
|
result = sysfs_name_compare(hash, name, ns, sd);
|
|
if (result < 0)
|
|
node = node->rb_left;
|
|
else if (result > 0)
|
|
node = node->rb_right;
|
|
else
|
|
return sd;
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
/**
|
|
* kernfs_find_and_get_ns - find and get sysfs_dirent with the given name
|
|
* @parent: sysfs_dirent to search under
|
|
* @name: name to look for
|
|
* @ns: the namespace tag to use
|
|
*
|
|
* Look for sysfs_dirent with name @name under @parent and get a reference
|
|
* if found. This function may sleep and returns pointer to the found
|
|
* sysfs_dirent on success, %NULL on failure.
|
|
*/
|
|
struct sysfs_dirent *kernfs_find_and_get_ns(struct sysfs_dirent *parent,
|
|
const char *name, const void *ns)
|
|
{
|
|
struct sysfs_dirent *sd;
|
|
|
|
mutex_lock(&sysfs_mutex);
|
|
sd = kernfs_find_ns(parent, name, ns);
|
|
kernfs_get(sd);
|
|
mutex_unlock(&sysfs_mutex);
|
|
|
|
return sd;
|
|
}
|
|
EXPORT_SYMBOL_GPL(kernfs_find_and_get_ns);
|
|
|
|
/**
|
|
* kernfs_create_root - create a new kernfs hierarchy
|
|
* @priv: opaque data associated with the new directory
|
|
*
|
|
* Returns the root of the new hierarchy on success, ERR_PTR() value on
|
|
* failure.
|
|
*/
|
|
struct kernfs_root *kernfs_create_root(void *priv)
|
|
{
|
|
struct kernfs_root *root;
|
|
struct sysfs_dirent *sd;
|
|
|
|
root = kzalloc(sizeof(*root), GFP_KERNEL);
|
|
if (!root)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
ida_init(&root->ino_ida);
|
|
|
|
sd = sysfs_new_dirent(root, "", S_IFDIR | S_IRUGO | S_IXUGO, SYSFS_DIR);
|
|
if (!sd) {
|
|
ida_destroy(&root->ino_ida);
|
|
kfree(root);
|
|
return ERR_PTR(-ENOMEM);
|
|
}
|
|
|
|
sd->s_flags &= ~SYSFS_FLAG_REMOVED;
|
|
sd->priv = priv;
|
|
sd->s_dir.root = root;
|
|
|
|
root->sd = sd;
|
|
|
|
return root;
|
|
}
|
|
|
|
/**
|
|
* kernfs_destroy_root - destroy a kernfs hierarchy
|
|
* @root: root of the hierarchy to destroy
|
|
*
|
|
* Destroy the hierarchy anchored at @root by removing all existing
|
|
* directories and destroying @root.
|
|
*/
|
|
void kernfs_destroy_root(struct kernfs_root *root)
|
|
{
|
|
kernfs_remove(root->sd); /* will also free @root */
|
|
}
|
|
|
|
/**
|
|
* kernfs_create_dir_ns - create a directory
|
|
* @parent: parent in which to create a new directory
|
|
* @name: name of the new directory
|
|
* @priv: opaque data associated with the new directory
|
|
* @ns: optional namespace tag of the directory
|
|
*
|
|
* Returns the created node on success, ERR_PTR() value on failure.
|
|
*/
|
|
struct sysfs_dirent *kernfs_create_dir_ns(struct sysfs_dirent *parent,
|
|
const char *name, void *priv,
|
|
const void *ns)
|
|
{
|
|
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(kernfs_root(parent), name, mode, SYSFS_DIR);
|
|
if (!sd)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
sd->s_dir.root = parent->s_dir.root;
|
|
sd->s_ns = ns;
|
|
sd->priv = priv;
|
|
|
|
/* link in */
|
|
sysfs_addrm_start(&acxt);
|
|
rc = sysfs_add_one(&acxt, sd, parent);
|
|
sysfs_addrm_finish(&acxt);
|
|
|
|
if (!rc)
|
|
return sd;
|
|
|
|
kernfs_put(sd);
|
|
return ERR_PTR(rc);
|
|
}
|
|
|
|
static struct dentry *sysfs_lookup(struct inode *dir, struct dentry *dentry,
|
|
unsigned int flags)
|
|
{
|
|
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;
|
|
const void *ns = NULL;
|
|
|
|
mutex_lock(&sysfs_mutex);
|
|
|
|
if (kernfs_ns_enabled(parent_sd))
|
|
ns = sysfs_info(dir->i_sb)->ns;
|
|
|
|
sd = kernfs_find_ns(parent_sd, dentry->d_name.name, ns);
|
|
|
|
/* no such entry */
|
|
if (!sd) {
|
|
ret = ERR_PTR(-ENOENT);
|
|
goto out_unlock;
|
|
}
|
|
kernfs_get(sd);
|
|
dentry->d_fsdata = sd;
|
|
|
|
/* 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_materialise_unique(dentry, 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,
|
|
.removexattr = sysfs_removexattr,
|
|
.getxattr = sysfs_getxattr,
|
|
.listxattr = sysfs_listxattr,
|
|
};
|
|
|
|
static struct sysfs_dirent *sysfs_leftmost_descendant(struct sysfs_dirent *pos)
|
|
{
|
|
struct sysfs_dirent *last;
|
|
|
|
while (true) {
|
|
struct rb_node *rbn;
|
|
|
|
last = pos;
|
|
|
|
if (sysfs_type(pos) != SYSFS_DIR)
|
|
break;
|
|
|
|
rbn = rb_first(&pos->s_dir.children);
|
|
if (!rbn)
|
|
break;
|
|
|
|
pos = to_sysfs_dirent(rbn);
|
|
}
|
|
|
|
return last;
|
|
}
|
|
|
|
/**
|
|
* sysfs_next_descendant_post - find the next descendant for post-order walk
|
|
* @pos: the current position (%NULL to initiate traversal)
|
|
* @root: sysfs_dirent whose descendants to walk
|
|
*
|
|
* Find the next descendant to visit for post-order traversal of @root's
|
|
* descendants. @root is included in the iteration and the last node to be
|
|
* visited.
|
|
*/
|
|
static struct sysfs_dirent *sysfs_next_descendant_post(struct sysfs_dirent *pos,
|
|
struct sysfs_dirent *root)
|
|
{
|
|
struct rb_node *rbn;
|
|
|
|
lockdep_assert_held(&sysfs_mutex);
|
|
|
|
/* if first iteration, visit leftmost descendant which may be root */
|
|
if (!pos)
|
|
return sysfs_leftmost_descendant(root);
|
|
|
|
/* if we visited @root, we're done */
|
|
if (pos == root)
|
|
return NULL;
|
|
|
|
/* if there's an unvisited sibling, visit its leftmost descendant */
|
|
rbn = rb_next(&pos->s_rb);
|
|
if (rbn)
|
|
return sysfs_leftmost_descendant(to_sysfs_dirent(rbn));
|
|
|
|
/* no sibling left, visit parent */
|
|
return pos->s_parent;
|
|
}
|
|
|
|
static void __kernfs_remove(struct sysfs_addrm_cxt *acxt,
|
|
struct sysfs_dirent *sd)
|
|
{
|
|
struct sysfs_dirent *pos, *next;
|
|
|
|
if (!sd)
|
|
return;
|
|
|
|
pr_debug("sysfs %s: removing\n", sd->s_name);
|
|
|
|
next = NULL;
|
|
do {
|
|
pos = next;
|
|
next = sysfs_next_descendant_post(pos, sd);
|
|
if (pos)
|
|
sysfs_remove_one(acxt, pos);
|
|
} while (next);
|
|
}
|
|
|
|
/**
|
|
* kernfs_remove - remove a sysfs_dirent recursively
|
|
* @sd: the sysfs_dirent to remove
|
|
*
|
|
* Remove @sd along with all its subdirectories and files.
|
|
*/
|
|
void kernfs_remove(struct sysfs_dirent *sd)
|
|
{
|
|
struct sysfs_addrm_cxt acxt;
|
|
|
|
sysfs_addrm_start(&acxt);
|
|
__kernfs_remove(&acxt, sd);
|
|
sysfs_addrm_finish(&acxt);
|
|
}
|
|
|
|
/**
|
|
* kernfs_remove_by_name_ns - find a sysfs_dirent by name and remove it
|
|
* @dir_sd: parent of the target
|
|
* @name: name of the sysfs_dirent to remove
|
|
* @ns: namespace tag of the sysfs_dirent to remove
|
|
*
|
|
* Look for the sysfs_dirent with @name and @ns under @dir_sd and remove
|
|
* it. Returns 0 on success, -ENOENT if such entry doesn't exist.
|
|
*/
|
|
int kernfs_remove_by_name_ns(struct sysfs_dirent *dir_sd, const char *name,
|
|
const void *ns)
|
|
{
|
|
struct sysfs_addrm_cxt acxt;
|
|
struct sysfs_dirent *sd;
|
|
|
|
if (!dir_sd) {
|
|
WARN(1, KERN_WARNING "sysfs: can not remove '%s', no directory\n",
|
|
name);
|
|
return -ENOENT;
|
|
}
|
|
|
|
sysfs_addrm_start(&acxt);
|
|
|
|
sd = kernfs_find_ns(dir_sd, name, ns);
|
|
if (sd)
|
|
__kernfs_remove(&acxt, sd);
|
|
|
|
sysfs_addrm_finish(&acxt);
|
|
|
|
if (sd)
|
|
return 0;
|
|
else
|
|
return -ENOENT;
|
|
}
|
|
|
|
/**
|
|
* kernfs_rename_ns - move and rename a kernfs_node
|
|
* @sd: target node
|
|
* @new_parent: new parent to put @sd under
|
|
* @new_name: new name
|
|
* @new_ns: new namespace tag
|
|
*/
|
|
int kernfs_rename_ns(struct sysfs_dirent *sd, struct sysfs_dirent *new_parent,
|
|
const char *new_name, const void *new_ns)
|
|
{
|
|
int error;
|
|
|
|
mutex_lock(&sysfs_mutex);
|
|
|
|
error = 0;
|
|
if ((sd->s_parent == new_parent) && (sd->s_ns == new_ns) &&
|
|
(strcmp(sd->s_name, new_name) == 0))
|
|
goto out; /* nothing to rename */
|
|
|
|
error = -EEXIST;
|
|
if (kernfs_find_ns(new_parent, new_name, new_ns))
|
|
goto out;
|
|
|
|
/* rename sysfs_dirent */
|
|
if (strcmp(sd->s_name, new_name) != 0) {
|
|
error = -ENOMEM;
|
|
new_name = kstrdup(new_name, GFP_KERNEL);
|
|
if (!new_name)
|
|
goto out;
|
|
|
|
kfree(sd->s_name);
|
|
sd->s_name = new_name;
|
|
}
|
|
|
|
/*
|
|
* Move to the appropriate place in the appropriate directories rbtree.
|
|
*/
|
|
sysfs_unlink_sibling(sd);
|
|
kernfs_get(new_parent);
|
|
kernfs_put(sd->s_parent);
|
|
sd->s_ns = new_ns;
|
|
sd->s_hash = sysfs_name_hash(sd->s_name, sd->s_ns);
|
|
sd->s_parent = new_parent;
|
|
sysfs_link_sibling(sd);
|
|
|
|
error = 0;
|
|
out:
|
|
mutex_unlock(&sysfs_mutex);
|
|
return error;
|
|
}
|
|
|
|
/* 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)
|
|
{
|
|
kernfs_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;
|
|
kernfs_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 *file, struct dir_context *ctx)
|
|
{
|
|
struct dentry *dentry = file->f_path.dentry;
|
|
struct sysfs_dirent *parent_sd = dentry->d_fsdata;
|
|
struct sysfs_dirent *pos = file->private_data;
|
|
const void *ns = NULL;
|
|
|
|
if (!dir_emit_dots(file, ctx))
|
|
return 0;
|
|
mutex_lock(&sysfs_mutex);
|
|
|
|
if (kernfs_ns_enabled(parent_sd))
|
|
ns = sysfs_info(dentry->d_sb)->ns;
|
|
|
|
for (pos = sysfs_dir_pos(ns, parent_sd, ctx->pos, pos);
|
|
pos;
|
|
pos = sysfs_dir_next_pos(ns, parent_sd, ctx->pos, pos)) {
|
|
const char *name = pos->s_name;
|
|
unsigned int type = dt_type(pos);
|
|
int len = strlen(name);
|
|
ino_t ino = pos->s_ino;
|
|
|
|
ctx->pos = pos->s_hash;
|
|
file->private_data = pos;
|
|
kernfs_get(pos);
|
|
|
|
mutex_unlock(&sysfs_mutex);
|
|
if (!dir_emit(ctx, name, len, ino, type))
|
|
return 0;
|
|
mutex_lock(&sysfs_mutex);
|
|
}
|
|
mutex_unlock(&sysfs_mutex);
|
|
file->private_data = NULL;
|
|
ctx->pos = INT_MAX;
|
|
return 0;
|
|
}
|
|
|
|
static loff_t sysfs_dir_llseek(struct file *file, loff_t offset, int whence)
|
|
{
|
|
struct inode *inode = file_inode(file);
|
|
loff_t ret;
|
|
|
|
mutex_lock(&inode->i_mutex);
|
|
ret = generic_file_llseek(file, offset, whence);
|
|
mutex_unlock(&inode->i_mutex);
|
|
|
|
return ret;
|
|
}
|
|
|
|
const struct file_operations sysfs_dir_operations = {
|
|
.read = generic_read_dir,
|
|
.iterate = sysfs_readdir,
|
|
.release = sysfs_dir_release,
|
|
.llseek = sysfs_dir_llseek,
|
|
};
|