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 *handler, struct dentry *dentry,
34 struct inode *inode, const char *name, void *buffer,
35 size_t size, int flags);
36 int (*set)(const struct xattr_handler *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 *dentry, struct inode *inode,
50 const char *name, void *buffer, size_t size, int flags);
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(struct dentry *, const char *, const void *, size_t, int);
56 int __vfs_removexattr(struct dentry *, const char *);
57 int vfs_removexattr(struct dentry *, const char *);
58
59 ssize_t generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size);
60 ssize_t vfs_getxattr_alloc(struct dentry *dentry, const char *name,
61 char **xattr_value, size_t size, gfp_t flags);
62
xattr_prefix(const struct xattr_handler * handler)63 static inline const char *xattr_prefix(const struct xattr_handler *handler)
64 {
65 return handler->prefix ?: handler->name;
66 }
67
68 struct simple_xattrs {
69 struct list_head head;
70 spinlock_t lock;
71 };
72
73 struct simple_xattr {
74 struct list_head list;
75 char *name;
76 size_t size;
77 char value[0];
78 };
79
80 /*
81 * initialize the simple_xattrs structure
82 */
simple_xattrs_init(struct simple_xattrs * xattrs)83 static inline void simple_xattrs_init(struct simple_xattrs *xattrs)
84 {
85 INIT_LIST_HEAD(&xattrs->head);
86 spin_lock_init(&xattrs->lock);
87 }
88
89 /*
90 * free all the xattrs
91 */
simple_xattrs_free(struct simple_xattrs * xattrs)92 static inline void simple_xattrs_free(struct simple_xattrs *xattrs)
93 {
94 struct simple_xattr *xattr, *node;
95
96 list_for_each_entry_safe(xattr, node, &xattrs->head, list) {
97 kfree(xattr->name);
98 kfree(xattr);
99 }
100 }
101
102 struct simple_xattr *simple_xattr_alloc(const void *value, size_t size);
103 int simple_xattr_get(struct simple_xattrs *xattrs, const char *name,
104 void *buffer, size_t size);
105 int simple_xattr_set(struct simple_xattrs *xattrs, const char *name,
106 const void *value, size_t size, int flags);
107 ssize_t simple_xattr_list(struct inode *inode, struct simple_xattrs *xattrs, char *buffer,
108 size_t size);
109 void simple_xattr_list_add(struct simple_xattrs *xattrs,
110 struct simple_xattr *new_xattr);
111
112 #endif /* _LINUX_XATTR_H */
113