2 * Copyright (C) 2007 Red Hat. All rights reserved.
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
19 #include <linux/init.h>
21 #include <linux/slab.h>
22 #include <linux/rwsem.h>
23 #include <linux/xattr.h>
24 #include <linux/security.h>
26 #include "btrfs_inode.h"
27 #include "transaction.h"
32 ssize_t
__btrfs_getxattr(struct inode
*inode
, const char *name
,
33 void *buffer
, size_t size
)
35 struct btrfs_dir_item
*di
;
36 struct btrfs_root
*root
= BTRFS_I(inode
)->root
;
37 struct btrfs_path
*path
;
38 struct extent_buffer
*leaf
;
40 unsigned long data_ptr
;
42 path
= btrfs_alloc_path();
46 /* lookup the xattr by name */
47 di
= btrfs_lookup_xattr(NULL
, root
, path
, inode
->i_ino
, name
,
52 } else if (IS_ERR(di
)) {
57 leaf
= path
->nodes
[0];
58 /* if size is 0, that means we want the size of the attr */
60 ret
= btrfs_dir_data_len(leaf
, di
);
64 /* now get the data out of our dir_item */
65 if (btrfs_dir_data_len(leaf
, di
) > size
) {
71 * The way things are packed into the leaf is like this
72 * |struct btrfs_dir_item|name|data|
73 * where name is the xattr name, so security.foo, and data is the
74 * content of the xattr. data_ptr points to the location in memory
75 * where the data starts in the in memory leaf
77 data_ptr
= (unsigned long)((char *)(di
+ 1) +
78 btrfs_dir_name_len(leaf
, di
));
79 read_extent_buffer(leaf
, buffer
, data_ptr
,
80 btrfs_dir_data_len(leaf
, di
));
81 ret
= btrfs_dir_data_len(leaf
, di
);
84 btrfs_free_path(path
);
88 int __btrfs_setxattr(struct inode
*inode
, const char *name
,
89 const void *value
, size_t size
, int flags
)
91 struct btrfs_dir_item
*di
;
92 struct btrfs_root
*root
= BTRFS_I(inode
)->root
;
93 struct btrfs_trans_handle
*trans
;
94 struct btrfs_path
*path
;
97 path
= btrfs_alloc_path();
101 trans
= btrfs_join_transaction(root
, 1);
102 btrfs_set_trans_block_group(trans
, inode
);
104 /* first lets see if we already have this xattr */
105 di
= btrfs_lookup_xattr(trans
, root
, path
, inode
->i_ino
, name
,
112 /* ok we already have this xattr, lets remove it */
114 /* if we want create only exit */
115 if (flags
& XATTR_CREATE
) {
120 ret
= btrfs_delete_one_dir_name(trans
, root
, path
, di
);
123 btrfs_release_path(root
, path
);
125 /* if we don't have a value then we are removing the xattr */
131 btrfs_release_path(root
, path
);
133 if (flags
& XATTR_REPLACE
) {
134 /* we couldn't find the attr to replace */
140 /* ok we have to create a completely new xattr */
141 ret
= btrfs_insert_xattr_item(trans
, root
, name
, strlen(name
),
142 value
, size
, inode
->i_ino
);
149 inode
->i_ctime
= CURRENT_TIME
;
150 ret
= btrfs_update_inode(trans
, root
, inode
);
153 btrfs_end_transaction(trans
, root
);
154 btrfs_free_path(path
);
158 ssize_t
btrfs_listxattr(struct dentry
*dentry
, char *buffer
, size_t size
)
160 struct btrfs_key key
, found_key
;
161 struct inode
*inode
= dentry
->d_inode
;
162 struct btrfs_root
*root
= BTRFS_I(inode
)->root
;
163 struct btrfs_path
*path
;
164 struct btrfs_item
*item
;
165 struct extent_buffer
*leaf
;
166 struct btrfs_dir_item
*di
;
167 int ret
= 0, slot
, advance
;
168 size_t total_size
= 0, size_left
= size
;
169 unsigned long name_ptr
;
174 * ok we want all objects associated with this id.
175 * NOTE: we set key.offset = 0; because we want to start with the
176 * first xattr that we find and walk forward
178 key
.objectid
= inode
->i_ino
;
179 btrfs_set_key_type(&key
, BTRFS_XATTR_ITEM_KEY
);
182 path
= btrfs_alloc_path();
187 /* search for our xattrs */
188 ret
= btrfs_search_slot(NULL
, root
, &key
, path
, 0, 0);
193 leaf
= path
->nodes
[0];
194 nritems
= btrfs_header_nritems(leaf
);
195 slot
= path
->slots
[0];
197 /* this is where we start walking through the path */
198 if (advance
|| slot
>= nritems
) {
200 * if we've reached the last slot in this leaf we need
201 * to go to the next leaf and reset everything
203 if (slot
>= nritems
-1) {
204 ret
= btrfs_next_leaf(root
, path
);
207 leaf
= path
->nodes
[0];
208 nritems
= btrfs_header_nritems(leaf
);
209 slot
= path
->slots
[0];
212 * just walking through the slots on this leaf
220 item
= btrfs_item_nr(leaf
, slot
);
221 btrfs_item_key_to_cpu(leaf
, &found_key
, slot
);
223 /* check to make sure this item is what we want */
224 if (found_key
.objectid
!= key
.objectid
)
226 if (btrfs_key_type(&found_key
) != BTRFS_XATTR_ITEM_KEY
)
229 di
= btrfs_item_ptr(leaf
, slot
, struct btrfs_dir_item
);
231 name_len
= btrfs_dir_name_len(leaf
, di
);
232 total_size
+= name_len
+ 1;
234 /* we are just looking for how big our buffer needs to be */
238 if (!buffer
|| (name_len
+ 1) > size_left
) {
243 name_ptr
= (unsigned long)(di
+ 1);
244 read_extent_buffer(leaf
, buffer
, name_ptr
, name_len
);
245 buffer
[name_len
] = '\0';
247 size_left
-= name_len
+ 1;
248 buffer
+= name_len
+ 1;
253 btrfs_free_path(path
);
259 * List of handlers for synthetic system.* attributes. All real ondisk
260 * attributes are handled directly.
262 struct xattr_handler
*btrfs_xattr_handlers
[] = {
263 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
264 &btrfs_xattr_acl_access_handler
,
265 &btrfs_xattr_acl_default_handler
,
271 * Check if the attribute is in a supported namespace.
273 * This applied after the check for the synthetic attributes in the system
276 static bool btrfs_is_valid_xattr(const char *name
)
278 return !strncmp(name
, XATTR_SECURITY_PREFIX
,
279 XATTR_SECURITY_PREFIX_LEN
) ||
280 !strncmp(name
, XATTR_SYSTEM_PREFIX
, XATTR_SYSTEM_PREFIX_LEN
) ||
281 !strncmp(name
, XATTR_TRUSTED_PREFIX
, XATTR_TRUSTED_PREFIX_LEN
) ||
282 !strncmp(name
, XATTR_USER_PREFIX
, XATTR_USER_PREFIX_LEN
);
285 ssize_t
btrfs_getxattr(struct dentry
*dentry
, const char *name
,
286 void *buffer
, size_t size
)
289 * If this is a request for a synthetic attribute in the system.*
290 * namespace use the generic infrastructure to resolve a handler
291 * for it via sb->s_xattr.
293 if (!strncmp(name
, XATTR_SYSTEM_PREFIX
, XATTR_SYSTEM_PREFIX_LEN
))
294 return generic_getxattr(dentry
, name
, buffer
, size
);
296 if (!btrfs_is_valid_xattr(name
))
298 return __btrfs_getxattr(dentry
->d_inode
, name
, buffer
, size
);
301 int btrfs_setxattr(struct dentry
*dentry
, const char *name
, const void *value
,
302 size_t size
, int flags
)
305 * If this is a request for a synthetic attribute in the system.*
306 * namespace use the generic infrastructure to resolve a handler
307 * for it via sb->s_xattr.
309 if (!strncmp(name
, XATTR_SYSTEM_PREFIX
, XATTR_SYSTEM_PREFIX_LEN
))
310 return generic_setxattr(dentry
, name
, value
, size
, flags
);
312 if (!btrfs_is_valid_xattr(name
))
316 value
= ""; /* empty EA, do not remove */
317 return __btrfs_setxattr(dentry
->d_inode
, name
, value
, size
, flags
);
320 int btrfs_removexattr(struct dentry
*dentry
, const char *name
)
323 * If this is a request for a synthetic attribute in the system.*
324 * namespace use the generic infrastructure to resolve a handler
325 * for it via sb->s_xattr.
327 if (!strncmp(name
, XATTR_SYSTEM_PREFIX
, XATTR_SYSTEM_PREFIX_LEN
))
328 return generic_removexattr(dentry
, name
);
330 if (!btrfs_is_valid_xattr(name
))
332 return __btrfs_setxattr(dentry
->d_inode
, name
, NULL
, 0, XATTR_REPLACE
);
335 int btrfs_xattr_security_init(struct inode
*inode
, struct inode
*dir
)
343 err
= security_inode_init_security(inode
, dir
, &suffix
, &value
, &len
);
345 if (err
== -EOPNOTSUPP
)
350 name
= kmalloc(XATTR_SECURITY_PREFIX_LEN
+ strlen(suffix
) + 1,
355 strcpy(name
, XATTR_SECURITY_PREFIX
);
356 strcpy(name
+ XATTR_SECURITY_PREFIX_LEN
, suffix
);
357 err
= __btrfs_setxattr(inode
, name
, value
, len
, 0);