1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 File: linux/xattr.h
4
5 Extended attributes handling.
6
7 Copyright (C) 2001 by Andreas Gruenbacher <a.gruenbacher@computer.org>
8 Copyright (c) 2001-2002 Silicon Graphics, Inc. All Rights Reserved.
9 Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com>
10 */
11 #ifndef _LINUX_XATTR_H
12 #define _LINUX_XATTR_H
13
14
15 #include <linux/slab.h>
16 #include <linux/types.h>
17 #include <linux/spinlock.h>
18 #include <linux/mm.h>
19 #include <uapi/linux/xattr.h>
20
21 struct inode;
22 struct dentry;
23
24 /*
25 * struct xattr_handler: When @name is set, match attributes with exactly that
26 * name. When @prefix is set instead, match attributes with that prefix and
27 * with a non-empty suffix.
28 */
29 struct xattr_handler {
30 const char *name;
31 const char *prefix;
32 int flags; /* fs private flags */
33 bool (*list)(struct dentry *dentry);
34 int (*get)(const struct xattr_handler *, struct dentry *dentry,
35 struct inode *inode, const char *name, void *buffer,
36 size_t size);
37 int (*set)(const struct xattr_handler *, struct dentry *dentry,
38 struct inode *inode, const char *name, const void *buffer,
39 size_t size, int flags);
40 };
41
42 const char *xattr_full_name(const struct xattr_handler *, const char *);
43
44 struct xattr {
45 const char *name;
46 void *value;
47 size_t value_len;
48 };
49
50 ssize_t __vfs_getxattr(struct dentry *, struct inode *, const char *, void *, size_t);
51 ssize_t vfs_getxattr(struct dentry *, const char *, void *, size_t);
52 ssize_t vfs_listxattr(struct dentry *d, char *list, size_t size);
53 int __vfs_setxattr(struct dentry *, struct inode *, const char *, const void *, size_t, int);
54 int __vfs_setxattr_noperm(struct dentry *, const char *, const void *, size_t, int);
55 int __vfs_setxattr_locked(struct dentry *, const char *, const void *, size_t, int, struct inode **);
56 int vfs_setxattr(struct dentry *, const char *, const void *, size_t, int);
57 int __vfs_removexattr(struct dentry *, const char *);
58 int __vfs_removexattr_locked(struct dentry *, const char *, struct inode **);
59 int vfs_removexattr(struct dentry *, const char *);
60
61 ssize_t generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size);
62 ssize_t vfs_getxattr_alloc(struct dentry *dentry, const char *name,
63 char **xattr_value, size_t size, gfp_t flags);
64
65 int xattr_supported_namespace(struct inode *inode, const char *prefix);
66
xattr_prefix(const struct xattr_handler * handler)67 static inline const char *xattr_prefix(const struct xattr_handler *handler)
68 {
69 return handler->prefix ?: handler->name;
70 }
71
72 struct simple_xattrs {
73 struct list_head head;
74 spinlock_t lock;
75 };
76
77 struct simple_xattr {
78 struct list_head list;
79 char *name;
80 size_t size;
81 char value[];
82 };
83
84 /*
85 * initialize the simple_xattrs structure
86 */
simple_xattrs_init(struct simple_xattrs * xattrs)87 static inline void simple_xattrs_init(struct simple_xattrs *xattrs)
88 {
89 INIT_LIST_HEAD(&xattrs->head);
90 spin_lock_init(&xattrs->lock);
91 }
92
93 /*
94 * free all the xattrs
95 */
simple_xattrs_free(struct simple_xattrs * xattrs)96 static inline void simple_xattrs_free(struct simple_xattrs *xattrs)
97 {
98 struct simple_xattr *xattr, *node;
99
100 list_for_each_entry_safe(xattr, node, &xattrs->head, list) {
101 kfree(xattr->name);
102 kvfree(xattr);
103 }
104 }
105
106 struct simple_xattr *simple_xattr_alloc(const void *value, size_t size);
107 int simple_xattr_get(struct simple_xattrs *xattrs, const char *name,
108 void *buffer, size_t size);
109 int simple_xattr_set(struct simple_xattrs *xattrs, const char *name,
110 const void *value, size_t size, int flags,
111 ssize_t *removed_size);
112 ssize_t simple_xattr_list(struct inode *inode, struct simple_xattrs *xattrs, char *buffer,
113 size_t size);
114 void simple_xattr_list_add(struct simple_xattrs *xattrs,
115 struct simple_xattr *new_xattr);
116
117 #endif /* _LINUX_XATTR_H */
118
