2 * Copyright (c) 2008, Christoph Hellwig
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License as
7 * published by the Free Software Foundation.
9 * This program is distributed in the hope that it would be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
21 #include "xfs_bmap_btree.h"
22 #include "xfs_inode.h"
23 #include "xfs_vnodeops.h"
24 #include <linux/xattr.h>
25 #include <linux/posix_acl_xattr.h>
30 * - all ACL updates are protected by inode->i_mutex, which is taken before
31 * calling into this file.
34 STATIC struct posix_acl *
35 xfs_acl_from_disk(struct xfs_acl *aclp)
37 struct posix_acl_entry *acl_e;
38 struct posix_acl *acl;
39 struct xfs_acl_entry *ace;
42 count = be32_to_cpu(aclp->acl_cnt);
44 acl = posix_acl_alloc(count, GFP_KERNEL);
46 return ERR_PTR(-ENOMEM);
48 for (i = 0; i < count; i++) {
49 acl_e = &acl->a_entries[i];
50 ace = &aclp->acl_entry[i];
53 * The tag is 32 bits on disk and 16 bits in core.
55 * Because every access to it goes through the core
56 * format first this is not a problem.
58 acl_e->e_tag = be32_to_cpu(ace->ae_tag);
59 acl_e->e_perm = be16_to_cpu(ace->ae_perm);
61 switch (acl_e->e_tag) {
64 acl_e->e_id = be32_to_cpu(ace->ae_id);
70 acl_e->e_id = ACL_UNDEFINED_ID;
79 posix_acl_release(acl);
80 return ERR_PTR(-EINVAL);
84 xfs_acl_to_disk(struct xfs_acl *aclp, const struct posix_acl *acl)
86 const struct posix_acl_entry *acl_e;
87 struct xfs_acl_entry *ace;
90 aclp->acl_cnt = cpu_to_be32(acl->a_count);
91 for (i = 0; i < acl->a_count; i++) {
92 ace = &aclp->acl_entry[i];
93 acl_e = &acl->a_entries[i];
95 ace->ae_tag = cpu_to_be32(acl_e->e_tag);
96 ace->ae_id = cpu_to_be32(acl_e->e_id);
97 ace->ae_perm = cpu_to_be16(acl_e->e_perm);
102 xfs_get_acl(struct inode *inode, int type)
104 struct xfs_inode *ip = XFS_I(inode);
105 struct posix_acl *acl;
106 struct xfs_acl *xfs_acl;
107 int len = sizeof(struct xfs_acl);
111 acl = get_cached_acl(inode, type);
112 if (acl != ACL_NOT_CACHED)
116 case ACL_TYPE_ACCESS:
117 ea_name = SGI_ACL_FILE;
119 case ACL_TYPE_DEFAULT:
120 ea_name = SGI_ACL_DEFAULT;
127 * If we have a cached ACLs value just return it, not need to
128 * go out to the disk.
131 xfs_acl = kzalloc(sizeof(struct xfs_acl), GFP_KERNEL);
133 return ERR_PTR(-ENOMEM);
135 error = -xfs_attr_get(ip, ea_name, (char *)xfs_acl, &len, ATTR_ROOT);
138 * If the attribute doesn't exist make sure we have a negative
139 * cache entry, for any other error assume it is transient and
140 * leave the cache entry as ACL_NOT_CACHED.
142 if (error == -ENOATTR) {
144 goto out_update_cache;
149 acl = xfs_acl_from_disk(xfs_acl);
154 set_cached_acl(inode, type, acl);
161 xfs_set_acl(struct inode *inode, int type, struct posix_acl *acl)
163 struct xfs_inode *ip = XFS_I(inode);
167 if (S_ISLNK(inode->i_mode))
171 case ACL_TYPE_ACCESS:
172 ea_name = SGI_ACL_FILE;
174 case ACL_TYPE_DEFAULT:
175 if (!S_ISDIR(inode->i_mode))
176 return acl ? -EACCES : 0;
177 ea_name = SGI_ACL_DEFAULT;
184 struct xfs_acl *xfs_acl;
187 xfs_acl = kzalloc(sizeof(struct xfs_acl), GFP_KERNEL);
191 xfs_acl_to_disk(xfs_acl, acl);
192 len = sizeof(struct xfs_acl) -
193 (sizeof(struct xfs_acl_entry) *
194 (XFS_ACL_MAX_ENTRIES - acl->a_count));
196 error = -xfs_attr_set(ip, ea_name, (char *)xfs_acl,
202 * A NULL ACL argument means we want to remove the ACL.
204 error = -xfs_attr_remove(ip, ea_name, ATTR_ROOT);
207 * If the attribute didn't exist to start with that's fine.
209 if (error == -ENOATTR)
214 set_cached_acl(inode, type, acl);
219 xfs_check_acl(struct inode *inode, int mask)
221 struct xfs_inode *ip = XFS_I(inode);
222 struct posix_acl *acl;
225 xfs_itrace_entry(ip);
228 * If there is no attribute fork no ACL exists on this inode and
229 * we can skip the whole exercise.
231 if (!XFS_IFORK_Q(ip))
234 acl = xfs_get_acl(inode, ACL_TYPE_ACCESS);
238 error = posix_acl_permission(inode, acl, mask);
239 posix_acl_release(acl);
246 xfs_set_mode(struct inode *inode, mode_t mode)
250 if (mode != inode->i_mode) {
253 iattr.ia_valid = ATTR_MODE;
254 iattr.ia_mode = mode;
256 error = -xfs_setattr(XFS_I(inode), &iattr, XFS_ATTR_NOACL);
263 xfs_acl_exists(struct inode *inode, char *name)
265 int len = sizeof(struct xfs_acl);
267 return (xfs_attr_get(XFS_I(inode), name, NULL, &len,
268 ATTR_ROOT|ATTR_KERNOVAL) == 0);
272 posix_acl_access_exists(struct inode *inode)
274 return xfs_acl_exists(inode, SGI_ACL_FILE);
278 posix_acl_default_exists(struct inode *inode)
280 if (!S_ISDIR(inode->i_mode))
282 return xfs_acl_exists(inode, SGI_ACL_DEFAULT);
286 * No need for i_mutex because the inode is not yet exposed to the VFS.
289 xfs_inherit_acl(struct inode *inode, struct posix_acl *default_acl)
291 struct posix_acl *clone;
293 int error = 0, inherit = 0;
295 if (S_ISDIR(inode->i_mode)) {
296 error = xfs_set_acl(inode, ACL_TYPE_DEFAULT, default_acl);
301 clone = posix_acl_clone(default_acl, GFP_KERNEL);
305 mode = inode->i_mode;
306 error = posix_acl_create_masq(clone, &mode);
308 goto out_release_clone;
311 * If posix_acl_create_masq returns a positive value we need to
312 * inherit a permission that can't be represented using the Unix
313 * mode bits and we actually need to set an ACL.
318 error = xfs_set_mode(inode, mode);
320 goto out_release_clone;
323 error = xfs_set_acl(inode, ACL_TYPE_ACCESS, clone);
326 posix_acl_release(clone);
331 xfs_acl_chmod(struct inode *inode)
333 struct posix_acl *acl, *clone;
336 if (S_ISLNK(inode->i_mode))
339 acl = xfs_get_acl(inode, ACL_TYPE_ACCESS);
340 if (IS_ERR(acl) || !acl)
343 clone = posix_acl_clone(acl, GFP_KERNEL);
344 posix_acl_release(acl);
348 error = posix_acl_chmod_masq(clone, inode->i_mode);
350 error = xfs_set_acl(inode, ACL_TYPE_ACCESS, clone);
352 posix_acl_release(clone);
357 * System xattr handlers.
359 * Currently Posix ACLs are the only system namespace extended attribute
360 * handlers supported by XFS, so we just implement the handlers here.
361 * If we ever support other system extended attributes this will need
366 xfs_decode_acl(const char *name)
368 if (strcmp(name, "posix_acl_access") == 0)
369 return ACL_TYPE_ACCESS;
370 else if (strcmp(name, "posix_acl_default") == 0)
371 return ACL_TYPE_DEFAULT;
376 xfs_xattr_system_get(struct inode *inode, const char *name,
377 void *value, size_t size)
379 struct posix_acl *acl;
382 type = xfs_decode_acl(name);
386 acl = xfs_get_acl(inode, type);
392 error = posix_acl_to_xattr(acl, value, size);
393 posix_acl_release(acl);
399 xfs_xattr_system_set(struct inode *inode, const char *name,
400 const void *value, size_t size, int flags)
402 struct posix_acl *acl = NULL;
405 type = xfs_decode_acl(name);
408 if (flags & XATTR_CREATE)
410 if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode))
411 return value ? -EACCES : 0;
412 if ((current_fsuid() != inode->i_uid) && !capable(CAP_FOWNER))
418 acl = posix_acl_from_xattr(value, size);
421 * acl_set_file(3) may request that we set default ACLs with
422 * zero length -- defend (gracefully) against that here.
427 error = PTR_ERR(acl);
431 error = posix_acl_valid(acl);
436 if (acl->a_count > XFS_ACL_MAX_ENTRIES)
439 if (type == ACL_TYPE_ACCESS) {
440 mode_t mode = inode->i_mode;
441 error = posix_acl_equiv_mode(acl, &mode);
444 posix_acl_release(acl);
451 error = xfs_set_mode(inode, mode);
457 error = xfs_set_acl(inode, type, acl);
459 posix_acl_release(acl);
464 struct xattr_handler xfs_xattr_system_handler = {
465 .prefix = XATTR_SYSTEM_PREFIX,
466 .get = xfs_xattr_system_get,
467 .set = xfs_xattr_system_set,