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 "xfs_trace.h"
25 #include <linux/slab.h>
26 #include <linux/xattr.h>
27 #include <linux/posix_acl_xattr.h>
32 * - all ACL updates are protected by inode->i_mutex, which is taken before
33 * calling into this file.
36 STATIC struct posix_acl *
37 xfs_acl_from_disk(struct xfs_acl *aclp)
39 struct posix_acl_entry *acl_e;
40 struct posix_acl *acl;
41 struct xfs_acl_entry *ace;
44 count = be32_to_cpu(aclp->acl_cnt);
46 acl = posix_acl_alloc(count, GFP_KERNEL);
48 return ERR_PTR(-ENOMEM);
50 for (i = 0; i < count; i++) {
51 acl_e = &acl->a_entries[i];
52 ace = &aclp->acl_entry[i];
55 * The tag is 32 bits on disk and 16 bits in core.
57 * Because every access to it goes through the core
58 * format first this is not a problem.
60 acl_e->e_tag = be32_to_cpu(ace->ae_tag);
61 acl_e->e_perm = be16_to_cpu(ace->ae_perm);
63 switch (acl_e->e_tag) {
66 acl_e->e_id = be32_to_cpu(ace->ae_id);
72 acl_e->e_id = ACL_UNDEFINED_ID;
81 posix_acl_release(acl);
82 return ERR_PTR(-EINVAL);
86 xfs_acl_to_disk(struct xfs_acl *aclp, const struct posix_acl *acl)
88 const struct posix_acl_entry *acl_e;
89 struct xfs_acl_entry *ace;
92 aclp->acl_cnt = cpu_to_be32(acl->a_count);
93 for (i = 0; i < acl->a_count; i++) {
94 ace = &aclp->acl_entry[i];
95 acl_e = &acl->a_entries[i];
97 ace->ae_tag = cpu_to_be32(acl_e->e_tag);
98 ace->ae_id = cpu_to_be32(acl_e->e_id);
99 ace->ae_perm = cpu_to_be16(acl_e->e_perm);
104 xfs_get_acl(struct inode *inode, int type)
106 struct xfs_inode *ip = XFS_I(inode);
107 struct posix_acl *acl;
108 struct xfs_acl *xfs_acl;
109 int len = sizeof(struct xfs_acl);
110 unsigned char *ea_name;
113 acl = get_cached_acl(inode, type);
114 if (acl != ACL_NOT_CACHED)
118 case ACL_TYPE_ACCESS:
119 ea_name = SGI_ACL_FILE;
121 case ACL_TYPE_DEFAULT:
122 ea_name = SGI_ACL_DEFAULT;
129 * If we have a cached ACLs value just return it, not need to
130 * go out to the disk.
133 xfs_acl = kzalloc(sizeof(struct xfs_acl), GFP_KERNEL);
135 return ERR_PTR(-ENOMEM);
137 error = -xfs_attr_get(ip, ea_name, (unsigned char *)xfs_acl,
141 * If the attribute doesn't exist make sure we have a negative
142 * cache entry, for any other error assume it is transient and
143 * leave the cache entry as ACL_NOT_CACHED.
145 if (error == -ENOATTR) {
147 goto out_update_cache;
152 acl = xfs_acl_from_disk(xfs_acl);
157 set_cached_acl(inode, type, acl);
164 xfs_set_acl(struct inode *inode, int type, struct posix_acl *acl)
166 struct xfs_inode *ip = XFS_I(inode);
167 unsigned char *ea_name;
170 if (S_ISLNK(inode->i_mode))
174 case ACL_TYPE_ACCESS:
175 ea_name = SGI_ACL_FILE;
177 case ACL_TYPE_DEFAULT:
178 if (!S_ISDIR(inode->i_mode))
179 return acl ? -EACCES : 0;
180 ea_name = SGI_ACL_DEFAULT;
187 struct xfs_acl *xfs_acl;
190 xfs_acl = kzalloc(sizeof(struct xfs_acl), GFP_KERNEL);
194 xfs_acl_to_disk(xfs_acl, acl);
195 len = sizeof(struct xfs_acl) -
196 (sizeof(struct xfs_acl_entry) *
197 (XFS_ACL_MAX_ENTRIES - acl->a_count));
199 error = -xfs_attr_set(ip, ea_name, (unsigned char *)xfs_acl,
205 * A NULL ACL argument means we want to remove the ACL.
207 error = -xfs_attr_remove(ip, ea_name, ATTR_ROOT);
210 * If the attribute didn't exist to start with that's fine.
212 if (error == -ENOATTR)
217 set_cached_acl(inode, type, acl);
222 xfs_check_acl(struct inode *inode, int mask)
224 struct xfs_inode *ip = XFS_I(inode);
225 struct posix_acl *acl;
228 xfs_itrace_entry(ip);
231 * If there is no attribute fork no ACL exists on this inode and
232 * we can skip the whole exercise.
234 if (!XFS_IFORK_Q(ip))
237 acl = xfs_get_acl(inode, ACL_TYPE_ACCESS);
241 error = posix_acl_permission(inode, acl, mask);
242 posix_acl_release(acl);
249 xfs_set_mode(struct inode *inode, mode_t mode)
253 if (mode != inode->i_mode) {
256 iattr.ia_valid = ATTR_MODE | ATTR_CTIME;
257 iattr.ia_mode = mode;
258 iattr.ia_ctime = current_fs_time(inode->i_sb);
260 error = -xfs_setattr(XFS_I(inode), &iattr, XFS_ATTR_NOACL);
267 xfs_acl_exists(struct inode *inode, unsigned char *name)
269 int len = sizeof(struct xfs_acl);
271 return (xfs_attr_get(XFS_I(inode), name, NULL, &len,
272 ATTR_ROOT|ATTR_KERNOVAL) == 0);
276 posix_acl_access_exists(struct inode *inode)
278 return xfs_acl_exists(inode, SGI_ACL_FILE);
282 posix_acl_default_exists(struct inode *inode)
284 if (!S_ISDIR(inode->i_mode))
286 return xfs_acl_exists(inode, SGI_ACL_DEFAULT);
290 * No need for i_mutex because the inode is not yet exposed to the VFS.
293 xfs_inherit_acl(struct inode *inode, struct posix_acl *default_acl)
295 struct posix_acl *clone;
297 int error = 0, inherit = 0;
299 if (S_ISDIR(inode->i_mode)) {
300 error = xfs_set_acl(inode, ACL_TYPE_DEFAULT, default_acl);
305 clone = posix_acl_clone(default_acl, GFP_KERNEL);
309 mode = inode->i_mode;
310 error = posix_acl_create_masq(clone, &mode);
312 goto out_release_clone;
315 * If posix_acl_create_masq returns a positive value we need to
316 * inherit a permission that can't be represented using the Unix
317 * mode bits and we actually need to set an ACL.
322 error = xfs_set_mode(inode, mode);
324 goto out_release_clone;
327 error = xfs_set_acl(inode, ACL_TYPE_ACCESS, clone);
330 posix_acl_release(clone);
335 xfs_acl_chmod(struct inode *inode)
337 struct posix_acl *acl, *clone;
340 if (S_ISLNK(inode->i_mode))
343 acl = xfs_get_acl(inode, ACL_TYPE_ACCESS);
344 if (IS_ERR(acl) || !acl)
347 clone = posix_acl_clone(acl, GFP_KERNEL);
348 posix_acl_release(acl);
352 error = posix_acl_chmod_masq(clone, inode->i_mode);
354 error = xfs_set_acl(inode, ACL_TYPE_ACCESS, clone);
356 posix_acl_release(clone);
361 xfs_xattr_acl_get(struct dentry *dentry, const char *name,
362 void *value, size_t size, int type)
364 struct posix_acl *acl;
367 acl = xfs_get_acl(dentry->d_inode, type);
373 error = posix_acl_to_xattr(acl, value, size);
374 posix_acl_release(acl);
380 xfs_xattr_acl_set(struct dentry *dentry, const char *name,
381 const void *value, size_t size, int flags, int type)
383 struct inode *inode = dentry->d_inode;
384 struct posix_acl *acl = NULL;
387 if (flags & XATTR_CREATE)
389 if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode))
390 return value ? -EACCES : 0;
391 if ((current_fsuid() != inode->i_uid) && !capable(CAP_FOWNER))
397 acl = posix_acl_from_xattr(value, size);
400 * acl_set_file(3) may request that we set default ACLs with
401 * zero length -- defend (gracefully) against that here.
406 error = PTR_ERR(acl);
410 error = posix_acl_valid(acl);
415 if (acl->a_count > XFS_ACL_MAX_ENTRIES)
418 if (type == ACL_TYPE_ACCESS) {
419 mode_t mode = inode->i_mode;
420 error = posix_acl_equiv_mode(acl, &mode);
423 posix_acl_release(acl);
430 error = xfs_set_mode(inode, mode);
436 error = xfs_set_acl(inode, type, acl);
438 posix_acl_release(acl);
443 struct xattr_handler xfs_xattr_acl_access_handler = {
444 .prefix = POSIX_ACL_XATTR_ACCESS,
445 .flags = ACL_TYPE_ACCESS,
446 .get = xfs_xattr_acl_get,
447 .set = xfs_xattr_acl_set,
450 struct xattr_handler xfs_xattr_acl_default_handler = {
451 .prefix = POSIX_ACL_XATTR_DEFAULT,
452 .flags = ACL_TYPE_DEFAULT,
453 .get = xfs_xattr_acl_get,
454 .set = xfs_xattr_acl_set,