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 <uapi/linux/xattr.h>
  13 #include <linux/posix_acl.h>
  14
  15 /* Supported ACL a_version fields */
  16 #define POSIX_ACL_XATTR_VERSION 0x0002
  17
  18 /* An undefined entry e_id value */
  19 #define ACL_UNDEFINED_ID        (-1)
  20
  21 typedef struct {
  22         __le16                  e_tag;
  23         __le16                  e_perm;
  24         __le32                  e_id;
  25 } posix_acl_xattr_entry;
  26
  27 typedef struct {
  28         __le32                  a_version;
  29         posix_acl_xattr_entry   a_entries[0];
  30 } posix_acl_xattr_header;
  31
  32
  33 static inline size_t
  34 posix_acl_xattr_size(int count)
  35 {
  36         return (sizeof(posix_acl_xattr_header) +
  37                 (count * sizeof(posix_acl_xattr_entry)));
  38 }
  39
  40 static inline int
  41 posix_acl_xattr_count(size_t size)
  42 {
  43         if (size < sizeof(posix_acl_xattr_header))
  44                 return -1;
  45         size -= sizeof(posix_acl_xattr_header);
  46         if (size % sizeof(posix_acl_xattr_entry))
  47                 return -1;
  48         return size / sizeof(posix_acl_xattr_entry);
  49 }
  50
  51 #ifdef CONFIG_FS_POSIX_ACL
  52 void posix_acl_fix_xattr_from_user(void *value, size_t size);
  53 void posix_acl_fix_xattr_to_user(void *value, size_t size);
  54 #else
  55 static inline void posix_acl_fix_xattr_from_user(void *value, size_t size)
  56 {
  57 }
  58 static inline void posix_acl_fix_xattr_to_user(void *value, size_t size)
  59 {
  60 }
  61 #endif
  62
  63 struct posix_acl *posix_acl_from_xattr(struct user_namespace *user_ns,
  64                                        const void *value, size_t size);
  65 int posix_acl_to_xattr(struct user_namespace *user_ns,
  66                        const struct posix_acl *acl, void *buffer, size_t size);
  67
  68 extern const struct xattr_handler posix_acl_access_xattr_handler;
  69 extern const struct xattr_handler posix_acl_default_xattr_handler;
  70
  71 #endif  /* _POSIX_ACL_XATTR_H */