/*
* Copyright (C) 2007 Red Hat. All rights reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License v2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public
* License along with this program; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 021110-1307, USA.
*/
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/rwsem.h>
#include <linux/xattr.h>
#include "ctree.h"
#include "btrfs_inode.h"
#include "transaction.h"
#include "xattr.h"
#include "disk-io.h"
static struct xattr_handler *btrfs_xattr_handler_map[] = {
[BTRFS_XATTR_INDEX_USER] = &btrfs_xattr_user_handler,
[BTRFS_XATTR_INDEX_POSIX_ACL_ACCESS] = &btrfs_xattr_acl_access_handler,
[BTRFS_XATTR_INDEX_POSIX_ACL_DEFAULT] = &btrfs_xattr_acl_default_handler,
[BTRFS_XATTR_INDEX_TRUSTED] = &btrfs_xattr_trusted_handler,
[BTRFS_XATTR_INDEX_SECURITY] = &btrfs_xattr_security_handler,
[BTRFS_XATTR_INDEX_SYSTEM] = &btrfs_xattr_system_handler,
};
struct xattr_handler *btrfs_xattr_handlers[] = {
&btrfs_xattr_user_handler,
&btrfs_xattr_acl_access_handler,
&btrfs_xattr_acl_default_handler,
&btrfs_xattr_trusted_handler,
&btrfs_xattr_security_handler,
&btrfs_xattr_system_handler,
NULL,
};
/*
* @param name - the xattr name
* @return - the xattr_handler for the xattr, NULL if its not found
*
* use this with listxattr where we don't already know the type of xattr we
* have
*/
static struct xattr_handler *find_btrfs_xattr_handler(struct extent_buffer *l,
unsigned long name_ptr,
u16 name_len)
{
struct xattr_handler *handler = NULL;
int i = 0;
for (handler = btrfs_xattr_handlers[i]; handler != NULL; i++,
handler = btrfs_xattr_handlers[i]) {
u16 prefix_len = strlen(handler->prefix);
if (name_len < prefix_len)
continue;
if (memcmp_extent_buffer(l, handler->prefix, name_ptr,
prefix_len) == 0)
break;
}
return handler;
}
/*
* @param name_index - the index for the xattr handler
* @return the xattr_handler if we found it, NULL otherwise
*
* use this if we know the type of the xattr already
*/
static struct xattr_handler *btrfs_xattr_handler(int name_index)
{
struct xattr_handler *handler = NULL;
if (name_index >= 0 &&
name_index < ARRAY_SIZE(btrfs_xattr_handler_map))
handler = btrfs_xattr_handler_map[name_index];
return handler;
}
static inline char *get_name(const char *name, int name_index)
{
char *ret = NULL;
struct xattr_handler *handler = btrfs_xattr_handler(name_index);
int prefix_len;
if (!handler)
return ret;
prefix_len = strlen(handler->prefix);
ret = kmalloc(strlen(name) + prefix_len + 1, GFP_KERNEL);
if (!ret)
return ret;
memcpy(ret, handler->prefix, prefix_len);
memcpy(ret+prefix_len, name, strlen(name));
ret[prefix_len + strlen(name)] = '\0';
return ret;
}
size_t btrfs_xattr_generic_list(struct inode *inode, char *list,
size_t list_size, const char *name,
size_t name_len)
{
if (list && (name_len+1) <= list_size) {
memcpy(list, name, name_len);
list[name_len] = '\0';
} else
return -ERANGE;
return name_len+1;
}
ssize_t btrfs_xattr_get(struct inode *inode, int name_index,
const char *attr_name, void *buffer, size_t size)
{
struct btrfs_dir_item *di;
struct btrfs_root *root = BTRFS_I(inode)->root;
struct btrfs_path *path;
struct extent_buffer *leaf;
struct xattr_handler *handler = btrfs_xattr_handler(name_index);
int ret = 0;
unsigned long data_ptr;
char *name;
if (!handler)
return -EOPNOTSUPP;
/* just in case... */
if (*attr_name == '\0')
return -EINVAL;
name = get_name(attr_name, name_index);
if (!name)
return -ENOMEM;
path = btrfs_alloc_path();
if (!path) {
kfree(name);
return -ENOMEM;
}
mutex_lock(&root->fs_info->fs_mutex);
/* lookup the xattr by name */
di = btrfs_lookup_xattr(NULL, root, path, inode->i_ino, name,
strlen(name), 0);
if (!di || IS_ERR(di)) {
ret = -ENODATA;
goto out;
}
leaf = path->nodes[0];
/* if size is 0, that means we want the size of the attr */
if (!size) {
ret = btrfs_dir_data_len(leaf, di);
goto out;
}
/* now get the data out of our dir_item */
if (btrfs_dir_data_len(leaf, di) > size) {
ret = -ERANGE;
goto out;
}
data_ptr = (unsigned long)((char *)(di + 1) +
btrfs_dir_name_len(leaf, di));
read_extent_buffer(leaf, buffer, data_ptr,
btrfs_dir_name_len(leaf, di));
ret = btrfs_dir_data_len(leaf, di);
out:
mutex_unlock(&root->fs_info->fs_mutex);
kfree(name);
btrfs_free_path(path);
return ret;
}
int btrfs_xattr_set(struct inode *inode, int name_index,
const char *attr_name, const void *value, size_t size,
int flags)
{
struct btrfs_dir_item *di;
struct btrfs_root *root = BTRFS_I(inode)->root;
struct btrfs_trans_handle *trans;
struct btrfs_path *path;
struct xattr_handler *handler = btrfs_xattr_handler(name_index);
char *name;
int ret = 0, mod = 0;
if (!handler)
return -EOPNOTSUPP;
/* just in case... */
if (*attr_name == '\0')
return -EINVAL;
name = get_name(attr_name, name_index);
if (!name)
return -ENOMEM;
path = btrfs_alloc_path();
if (!path) {
kfree(name);
return -ENOMEM;
}
mutex_lock(&root->fs_info->fs_mutex);
trans = btrfs_start_transaction(root, 1);
btrfs_set_trans_block_group(trans, inode);
/* first lets see if we already have this xattr */
di = btrfs_lookup_xattr(trans, root, path, inode->i_ino, name,
strlen(name), -1);
if (IS_ERR(di)) {
ret = PTR_ERR(di);
goto out;
}
/* ok we already have this xattr, lets remove it */
if (di) {
/* if we want create only exit */
if (flags & XATTR_CREATE) {
ret = -EEXIST;
goto out;
}
ret = btrfs_delete_one_dir_name(trans, root, path, di);
if (ret)
goto out;
btrfs_release_path(root, path);
/* if we don't have a value then we are removing the xattr */
if (!value) {
mod = 1;
goto out;
}
} else if (flags & XATTR_REPLACE) {
/* we couldn't find the attr to replace, so error out */
ret = -ENODATA;
goto out;
}
/* ok we have to create a completely new xattr */
ret = btrfs_insert_xattr_item(trans, root, name, strlen(name),
value, size, inode->i_ino);
if (ret)
goto out;
mod = 1;
out:
if (mod) {
inode->i_ctime = CURRENT_TIME;
ret = btrfs_update_inode(trans, root, inode);
}
btrfs_end_transaction(trans, root);
mutex_unlock(&root->fs_info->fs_mutex);
kfree(name);
btrfs_free_path(path);
return ret;
}
ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size)
{
struct btrfs_key key, found_key;
struct inode *inode = dentry->d_inode;
struct btrfs_root *root = BTRFS_I(inode)->root;
struct btrfs_path *path;
struct btrfs_item *item;
struct extent_buffer *leaf;
struct btrfs_dir_item *di;
struct xattr_handler *handler;
int ret = 0, slot, advance;
size_t total_size = 0, size_left = size, written;
unsigned long name_ptr;
char *name;
u32 nritems;
/*
* ok we want all objects associated with this id.
* NOTE: we set key.offset = 0; because we want to start with the
* first xattr that we find and walk forward
*/
key.objectid = inode->i_ino;
btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY);
key.offset = 0;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
path->reada = 2;
mutex_lock(&root->fs_info->fs_mutex);
/* search for our xattrs */
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret < 0)
goto err;
ret = 0;
advance = 0;
while (1) {
leaf = path->nodes[0];
nritems = btrfs_header_nritems(leaf);
slot = path->slots[0];
/* this is where we start walking through the path */
if (advance || slot >= nritems) {
/*
* if we've reached the last slot in this leaf we need
* to go to the next leaf and reset everything
*/
if (slot >= nritems-1) {
ret = btrfs_next_leaf(root, path);
if (ret)
break;
leaf = path->nodes[0];
nritems = btrfs_header_nritems(leaf);
slot = path->slots[0];
} else {
/*
* just walking through the slots on this leaf
*/
slot++;
path->slots[0]++;
}
}
advance = 1;
item = btrfs_item_nr(leaf, slot);
btrfs_item_key_to_cpu(leaf, &found_key, slot);
/* check to make sure this item is what we want */
if (found_key.objectid != key.objectid)
break;
if (btrfs_key_type(&found_key) != BTRFS_XATTR_ITEM_KEY)
break;
di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
total_size += btrfs_dir_name_len(leaf, di)+1;
/* we are just looking for how big our buffer needs to be */
if (!size)
continue;
/* find our handler for this xattr */
name_ptr = (unsigned long)(di + 1);
handler = find_btrfs_xattr_handler(leaf, name_ptr,
btrfs_dir_name_len(leaf, di));
if (!handler) {
printk(KERN_ERR "btrfs: unsupported xattr found\n");
continue;
}
name = kmalloc(btrfs_dir_name_len(leaf, di), GFP_KERNEL);
read_extent_buffer(leaf, name, name_ptr,
btrfs_dir_name_len(leaf, di));
/* call the list function associated with this xattr */
written = handler->list(inode, buffer, size_left, name,
btrfs_dir_name_len(leaf, di));
kfree(name);
if (written < 0) {
ret = -ERANGE;
break;
}
size_left -= written;
buffer += written;
}
ret = total_size;
err:
mutex_unlock(&root->fs_info->fs_mutex);
btrfs_free_path(path);
return ret;
}
/*
* delete all the xattrs associated with the inode. fs_mutex should be
* held when we come into here
*/
int btrfs_delete_xattrs(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct inode *inode)
{
struct btrfs_path *path;
struct btrfs_key key, found_key;
struct btrfs_item *item;
struct extent_buffer *leaf;
int ret;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
path->reada = -1;
key.objectid = inode->i_ino;
btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY);
key.offset = (u64)-1;
while(1) {
/* look for our next xattr */
ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
if (ret < 0)
goto out;
BUG_ON(ret == 0);
if (path->slots[0] == 0)
break;
path->slots[0]--;
leaf = path->nodes[0];
item = btrfs_item_nr(leaf, path->slots[0]);
btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
if (found_key.objectid != key.objectid)
break;
if (btrfs_key_type(&found_key) != BTRFS_XATTR_ITEM_KEY)
break;
ret = btrfs_del_item(trans, root, path);
BUG_ON(ret);
btrfs_release_path(root, path);
}
ret = 0;
out:
btrfs_free_path(path);
return ret;
}
/*
* Handler functions
*/
#define BTRFS_XATTR_SETGET_FUNCS(name, index) \
static int btrfs_xattr_##name##_get(struct inode *inode, \
const char *name, void *value, \
size_t size) \
{ \
return btrfs_xattr_get(inode, index, name, value, size); \
} \
static int btrfs_xattr_##name##_set(struct inode *inode, \
const char *name, const void *value,\
size_t size, int flags) \
{ \
return btrfs_xattr_set(inode, index, name, value, size, flags); \
} \
BTRFS_XATTR_SETGET_FUNCS(security, BTRFS_XATTR_INDEX_SECURITY);
BTRFS_XATTR_SETGET_FUNCS(system, BTRFS_XATTR_INDEX_SYSTEM);
BTRFS_XATTR_SETGET_FUNCS(user, BTRFS_XATTR_INDEX_USER);
BTRFS_XATTR_SETGET_FUNCS(trusted, BTRFS_XATTR_INDEX_TRUSTED);
struct xattr_handler btrfs_xattr_security_handler = {
.prefix = XATTR_SECURITY_PREFIX,
.list = btrfs_xattr_generic_list,
.get = btrfs_xattr_security_get,
.set = btrfs_xattr_security_set,
};
struct xattr_handler btrfs_xattr_system_handler = {
.prefix = XATTR_SYSTEM_PREFIX,
.list = btrfs_xattr_generic_list,
.get = btrfs_xattr_system_get,
.set = btrfs_xattr_system_set,
};
struct xattr_handler btrfs_xattr_user_handler = {
.prefix = XATTR_USER_PREFIX,
.list = btrfs_xattr_generic_list,
.get = btrfs_xattr_user_get,
.set = btrfs_xattr_user_set,
};
struct xattr_handler btrfs_xattr_trusted_handler = {
.prefix = XATTR_USER_PREFIX,
.list = btrfs_xattr_generic_list,
.get = btrfs_xattr_trusted_get,
.set = btrfs_xattr_trusted_set,
};
