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 #ifdef CONFIG_FS_POSIX_ACL
  56 void posix_acl_fix_xattr_from_user(void *value, size_t size);
  57 void posix_acl_fix_xattr_to_user(void *value, size_t size);
  58 #else
  59 static inline void posix_acl_fix_xattr_from_user(void *value, size_t size)
  60 {
  61 }
  62 static inline void posix_acl_fix_xattr_to_user(void *value, size_t size)
  63 {
  64 }
  65 #endif
  66
  67 struct posix_acl *posix_acl_from_xattr(struct user_namespace *user_ns,
  68                                        const void *value, size_t size);
  69 int posix_acl_to_xattr(struct user_namespace *user_ns,
  70                        const struct posix_acl *acl, void *buffer, size_t size);
  71
  72 #endif  /* _POSIX_ACL_XATTR_H */