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 *handler, struct dentry *dentry,
35 struct inode *inode, const char *name, void *buffer,
36 size_t size, int flags);
37 int (*set)(const struct xattr_handler *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 *dentry, struct inode *inode,
51 const char *name, void *buffer, size_t size, int flags);
52 ssize_t vfs_getxattr(struct dentry *, const char *, void *, size_t);
53 ssize_t vfs_listxattr(struct dentry *d, char *list, size_t size);
54 int __vfs_setxattr(struct dentry *, struct inode *, const char *, const void *, size_t, int);
55 int __vfs_setxattr_noperm(struct dentry *, const char *, const void *, size_t, int);
56 int __vfs_setxattr_locked(struct dentry *, const char *, const void *, size_t, int, struct inode **);
57 int vfs_setxattr(struct dentry *, const char *, const void *, size_t, int);
58 int __vfs_removexattr(struct dentry *, const char *);
59 int __vfs_removexattr_locked(struct dentry *, const char *, struct inode **);
60 int vfs_removexattr(struct dentry *, const char *);
61
62 ssize_t generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size);
63 ssize_t vfs_getxattr_alloc(struct dentry *dentry, const char *name,
64 char **xattr_value, size_t size, gfp_t flags);
65
66 int xattr_supported_namespace(struct inode *inode, const char *prefix);
67
xattr_prefix(const struct xattr_handler * handler)68 static inline const char *xattr_prefix(const struct xattr_handler *handler)
69 {
70 return handler->prefix ?: handler->name;
71 }
72
73 struct simple_xattrs {
74 struct list_head head;
75 spinlock_t lock;
76 };
77
78 struct simple_xattr {
79 struct list_head list;
80 char *name;
81 size_t size;
82 char value[];
83 };
84
85 /*
86 * initialize the simple_xattrs structure
87 */
simple_xattrs_init(struct simple_xattrs * xattrs)88 static inline void simple_xattrs_init(struct simple_xattrs *xattrs)
89 {
90 INIT_LIST_HEAD(&xattrs->head);
91 spin_lock_init(&xattrs->lock);
92 }
93
94 /*
95 * free all the xattrs
96 */
simple_xattrs_free(struct simple_xattrs * xattrs)97 static inline void simple_xattrs_free(struct simple_xattrs *xattrs)
98 {
99 struct simple_xattr *xattr, *node;
100
101 list_for_each_entry_safe(xattr, node, &xattrs->head, list) {
102 kfree(xattr->name);
103 kvfree(xattr);
104 }
105 }
106
107 struct simple_xattr *simple_xattr_alloc(const void *value, size_t size);
108 int simple_xattr_get(struct simple_xattrs *xattrs, const char *name,
109 void *buffer, size_t size);
110 int simple_xattr_set(struct simple_xattrs *xattrs, const char *name,
111 const void *value, size_t size, int flags,
112 ssize_t *removed_size);
113 ssize_t simple_xattr_list(struct inode *inode, struct simple_xattrs *xattrs, char *buffer,
114 size_t size);
115 void simple_xattr_list_add(struct simple_xattrs *xattrs,
116 struct simple_xattr *new_xattr);
117
118 #endif /* _LINUX_XATTR_H */
119