6e53c34035cd5b77c7c3e86878a00a3b1861070e
[linux-3.10.git] / include / linux / posix_acl_xattr.h
1 /*
2   File: linux/posix_acl_xattr.h
3
4   Extended attribute system call representation of Access Control Lists.
5
6   Copyright (C) 2000 by Andreas Gruenbacher <a.gruenbacher@computer.org>
7   Copyright (C) 2002 SGI - Silicon Graphics, Inc <linux-xfs@oss.sgi.com>
8  */
9 #ifndef _POSIX_ACL_XATTR_H
10 #define _POSIX_ACL_XATTR_H
11
12 #include <linux/posix_acl.h>
13
14 /* Extended attribute names */
15 #define POSIX_ACL_XATTR_ACCESS  "system.posix_acl_access"
16 #define POSIX_ACL_XATTR_DEFAULT "system.posix_acl_default"
17
18 /* Supported ACL a_version fields */
19 #define POSIX_ACL_XATTR_VERSION 0x0002
20
21
22 /* An undefined entry e_id value */
23 #define ACL_UNDEFINED_ID        (-1)
24
25 typedef struct {
26         __le16                  e_tag;
27         __le16                  e_perm;
28         __le32                  e_id;
29 } posix_acl_xattr_entry;
30
31 typedef struct {
32         __le32                  a_version;
33         posix_acl_xattr_entry   a_entries[0];
34 } posix_acl_xattr_header;
35
36
37 static inline size_t
38 posix_acl_xattr_size(int count)
39 {
40         return (sizeof(posix_acl_xattr_header) +
41                 (count * sizeof(posix_acl_xattr_entry)));
42 }
43
44 static inline int
45 posix_acl_xattr_count(size_t size)
46 {
47         if (size < sizeof(posix_acl_xattr_header))
48                 return -1;
49         size -= sizeof(posix_acl_xattr_header);
50         if (size % sizeof(posix_acl_xattr_entry))
51                 return -1;
52         return size / sizeof(posix_acl_xattr_entry);
53 }
54
55 struct posix_acl *posix_acl_from_xattr(const void *value, size_t size);
56 int posix_acl_to_xattr(const struct posix_acl *acl, void *buffer, size_t size);
57
58 #endif  /* _POSIX_ACL_XATTR_H */