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 <[email protected]>
8   Copyright (C) 2002 SGI - Silicon Graphics, Inc <[email protected]>
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 void posix_acl_fix_xattr_from_user(void *value, size_t size);
37 void posix_acl_fix_xattr_to_user(void *value, size_t size);
38 void posix_acl_getxattr_idmapped_mnt(struct user_namespace *mnt_userns,
39 				     const struct inode *inode,
40 				     void *value, size_t size);
41 #else
42 static inline void posix_acl_fix_xattr_from_user(void *value, size_t size)
43 {
44 }
45 static inline void posix_acl_fix_xattr_to_user(void *value, size_t size)
46 {
47 }
48 static inline void
49 posix_acl_getxattr_idmapped_mnt(struct user_namespace *mnt_userns,
50 				const struct inode *inode, void *value,
51 				size_t size)
52 {
53 }
54 #endif
55 
56 struct posix_acl *posix_acl_from_xattr(struct user_namespace *user_ns,
57 				       const void *value, size_t size);
58 int posix_acl_to_xattr(struct user_namespace *user_ns,
59 		       const struct posix_acl *acl, void *buffer, size_t size);
60 struct posix_acl *vfs_set_acl_prepare(struct user_namespace *mnt_userns,
61 				      struct user_namespace *fs_userns,
62 				      const void *value, size_t size);
63 
64 extern const struct xattr_handler posix_acl_access_xattr_handler;
65 extern const struct xattr_handler posix_acl_default_xattr_handler;
66 
67 #endif	/* _POSIX_ACL_XATTR_H */
68