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 <uapi/linux/xattr.h>
19
20 struct inode;
21 struct dentry;
22
23 /*
24 * struct xattr_handler: When @name is set, match attributes with exactly that
25 * name. When @prefix is set instead, match attributes with that prefix and
26 * with a non-empty suffix.
27 */
28 struct xattr_handler {
29 const char *name;
30 const char *prefix;
31 int flags; /* fs private flags */
32 bool (*list)(struct dentry *dentry);
33 int (*get)(const struct xattr_handler *, struct dentry *dentry,
34 struct inode *inode, const char *name, void *buffer,
35 size_t size);
36 int (*set)(const struct xattr_handler *, struct dentry *dentry,
37 struct inode *inode, const char *name, const void *buffer,
38 size_t size, int flags);
39 };
40
41 const char *xattr_full_name(const struct xattr_handler *, const char *);
42
43 struct xattr {
44 const char *name;
45 void *value;
46 size_t value_len;
47 };
48
49 ssize_t __vfs_getxattr(struct dentry *, struct inode *, const char *, void *, size_t);
50 ssize_t vfs_getxattr(struct dentry *, const char *, void *, size_t);
51 ssize_t vfs_listxattr(struct dentry *d, char *list, size_t size);
52 int __vfs_setxattr(struct dentry *, struct inode *, const char *, const void *, size_t, int);
53 int __vfs_setxattr_noperm(struct dentry *, const char *, const void *, size_t, int);
54 int __vfs_setxattr_locked(struct dentry *, const char *, const void *, size_t, int, struct inode **);
55 int vfs_setxattr(struct dentry *, const char *, const void *, size_t, int);
56 int __vfs_removexattr(struct dentry *, const char *);
57 int __vfs_removexattr_locked(struct dentry *, const char *, struct inode **);
58 int vfs_removexattr(struct dentry *, const char *);
59
60 ssize_t generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size);
61 ssize_t vfs_getxattr_alloc(struct dentry *dentry, const char *name,
62 char **xattr_value, size_t size, gfp_t flags);
63
xattr_prefix(const struct xattr_handler * handler)64 static inline const char *xattr_prefix(const struct xattr_handler *handler)
65 {
66 return handler->prefix ?: handler->name;
67 }
68
69 struct simple_xattrs {
70 struct list_head head;
71 spinlock_t lock;
72 };
73
74 struct simple_xattr {
75 struct list_head list;
76 char *name;
77 size_t size;
78 char value[0];
79 };
80
81 /*
82 * initialize the simple_xattrs structure
83 */
simple_xattrs_init(struct simple_xattrs * xattrs)84 static inline void simple_xattrs_init(struct simple_xattrs *xattrs)
85 {
86 INIT_LIST_HEAD(&xattrs->head);
87 spin_lock_init(&xattrs->lock);
88 }
89
90 /*
91 * free all the xattrs
92 */
simple_xattrs_free(struct simple_xattrs * xattrs)93 static inline void simple_xattrs_free(struct simple_xattrs *xattrs)
94 {
95 struct simple_xattr *xattr, *node;
96
97 list_for_each_entry_safe(xattr, node, &xattrs->head, list) {
98 kfree(xattr->name);
99 kfree(xattr);
100 }
101 }
102
103 struct simple_xattr *simple_xattr_alloc(const void *value, size_t size);
104 int simple_xattr_get(struct simple_xattrs *xattrs, const char *name,
105 void *buffer, size_t size);
106 int simple_xattr_set(struct simple_xattrs *xattrs, const char *name,
107 const void *value, size_t size, int flags);
108 ssize_t simple_xattr_list(struct inode *inode, struct simple_xattrs *xattrs, char *buffer,
109 size_t size);
110 void simple_xattr_list_add(struct simple_xattrs *xattrs,
111 struct simple_xattr *new_xattr);
112
113 #endif /* _LINUX_XATTR_H */
114