include/linux/posix_acl_xattr.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3   File: linux/posix_acl_xattr.h
   4
   5   Extended attribute system call representation of Access Control Lists.
   6
   7   Copyright (C) 2000 by Andreas Gruenbacher <a.gruenbacher@computer.org>
   8   Copyright (C) 2002 SGI - Silicon Graphics, Inc <linux-xfs@oss.sgi.com>
   9  */
  10 #ifndef _POSIX_ACL_XATTR_H
  11 #define _POSIX_ACL_XATTR_H
  12
  13 #include <uapi/linux/xattr.h>
  14 #include <uapi/linux/posix_acl_xattr.h>
  15 #include <linux/posix_acl.h>
  16
  17 static inline size_t
  18 posix_acl_xattr_size(int count)
  19 {
  20         return (sizeof(struct posix_acl_xattr_header) +
  21                 (count * sizeof(struct posix_acl_xattr_entry)));
  22 }
  23
  24 static inline int
  25 posix_acl_xattr_count(size_t size)
  26 {
  27         if (size < sizeof(struct posix_acl_xattr_header))
  28                 return -1;
  29         size -= sizeof(struct posix_acl_xattr_header);
  30         if (size % sizeof(struct posix_acl_xattr_entry))
  31                 return -1;
  32         return size / sizeof(struct posix_acl_xattr_entry);
  33 }
  34
  35 #ifdef CONFIG_FS_POSIX_ACL
  36 struct posix_acl *posix_acl_from_xattr(struct user_namespace *user_ns,
  37                                        const void *value, size_t size);
  38 #else
  39 static inline struct posix_acl *
  40 posix_acl_from_xattr(struct user_namespace *user_ns, const void *value,
  41                      size_t size)
  42 {
  43         return ERR_PTR(-EOPNOTSUPP);
  44 }
  45 #endif
  46
  47 int posix_acl_to_xattr(struct user_namespace *user_ns,
  48                        const struct posix_acl *acl, void *buffer, size_t size);
  49 static inline const char *posix_acl_xattr_name(int type)
  50 {
  51         switch (type) {
  52         case ACL_TYPE_ACCESS:
  53                 return XATTR_NAME_POSIX_ACL_ACCESS;
  54         case ACL_TYPE_DEFAULT:
  55                 return XATTR_NAME_POSIX_ACL_DEFAULT;
  56         }
  57
  58         return "";
  59 }
  60
  61 static inline int posix_acl_type(const char *name)
  62 {
  63         if (strcmp(name, XATTR_NAME_POSIX_ACL_ACCESS) == 0)
  64                 return ACL_TYPE_ACCESS;
  65         else if (strcmp(name, XATTR_NAME_POSIX_ACL_DEFAULT) == 0)
  66                 return ACL_TYPE_DEFAULT;
  67
  68         return -1;
  69 }
  70
  71 /* These are legacy handlers. Don't use them for new code. */
  72 extern const struct xattr_handler nop_posix_acl_access;
  73 extern const struct xattr_handler nop_posix_acl_default;
  74
  75 #endif  /* _POSIX_ACL_XATTR_H */