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 <linux/user_namespace.h>
20 #include <uapi/linux/xattr.h>
21
22 struct inode;
23 struct dentry;
24
25 /*
26 * struct xattr_handler: When @name is set, match attributes with exactly that
27 * name. When @prefix is set instead, match attributes with that prefix and
28 * with a non-empty suffix.
29 */
30 struct xattr_handler {
31 const char *name;
32 const char *prefix;
33 int flags; /* fs private flags */
34 bool (*list)(struct dentry *dentry);
35 int (*get)(const struct xattr_handler *, struct dentry *dentry,
36 struct inode *inode, const char *name, void *buffer,
37 size_t size);
38 int (*set)(const struct xattr_handler *,
39 struct user_namespace *mnt_userns, struct dentry *dentry,
40 struct inode *inode, const char *name, const void *buffer,
41 size_t size, int flags);
42 };
43
44 const char *xattr_full_name(const struct xattr_handler *, const char *);
45
46 struct xattr {
47 const char *name;
48 void *value;
49 size_t value_len;
50 };
51
52 ssize_t __vfs_getxattr(struct dentry *, struct inode *, const char *, void *, size_t);
53 ssize_t vfs_getxattr(struct user_namespace *, struct dentry *, const char *,
54 void *, size_t);
55 ssize_t vfs_listxattr(struct dentry *d, char *list, size_t size);
56 int __vfs_setxattr(struct user_namespace *, struct dentry *, struct inode *,
57 const char *, const void *, size_t, int);
58 int __vfs_setxattr_noperm(struct user_namespace *, struct dentry *,
59 const char *, const void *, size_t, int);
60 int __vfs_setxattr_locked(struct user_namespace *, struct dentry *,
61 const char *, const void *, size_t, int,
62 struct inode **);
63 int vfs_setxattr(struct user_namespace *, struct dentry *, const char *,
64 const void *, size_t, int);
65 int __vfs_removexattr(struct user_namespace *, struct dentry *, const char *);
66 int __vfs_removexattr_locked(struct user_namespace *, struct dentry *,
67 const char *, struct inode **);
68 int vfs_removexattr(struct user_namespace *, struct dentry *, const char *);
69
70 ssize_t generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size);
71 ssize_t vfs_getxattr_alloc(struct user_namespace *mnt_userns,
72 struct dentry *dentry, const char *name,
73 char **xattr_value, size_t size, gfp_t flags);
74
75 int xattr_supported_namespace(struct inode *inode, const char *prefix);
76
xattr_prefix(const struct xattr_handler * handler)77 static inline const char *xattr_prefix(const struct xattr_handler *handler)
78 {
79 return handler->prefix ?: handler->name;
80 }
81
82 struct simple_xattrs {
83 struct list_head head;
84 spinlock_t lock;
85 };
86
87 struct simple_xattr {
88 struct list_head list;
89 char *name;
90 size_t size;
91 char value[];
92 };
93
94 /*
95 * initialize the simple_xattrs structure
96 */
simple_xattrs_init(struct simple_xattrs * xattrs)97 static inline void simple_xattrs_init(struct simple_xattrs *xattrs)
98 {
99 INIT_LIST_HEAD(&xattrs->head);
100 spin_lock_init(&xattrs->lock);
101 }
102
103 /*
104 * free all the xattrs
105 */
simple_xattrs_free(struct simple_xattrs * xattrs)106 static inline void simple_xattrs_free(struct simple_xattrs *xattrs)
107 {
108 struct simple_xattr *xattr, *node;
109
110 list_for_each_entry_safe(xattr, node, &xattrs->head, list) {
111 kfree(xattr->name);
112 kvfree(xattr);
113 }
114 }
115
116 struct simple_xattr *simple_xattr_alloc(const void *value, size_t size);
117 int simple_xattr_get(struct simple_xattrs *xattrs, const char *name,
118 void *buffer, size_t size);
119 int simple_xattr_set(struct simple_xattrs *xattrs, const char *name,
120 const void *value, size_t size, int flags,
121 ssize_t *removed_size);
122 ssize_t simple_xattr_list(struct inode *inode, struct simple_xattrs *xattrs, char *buffer,
123 size_t size);
124 void simple_xattr_list_add(struct simple_xattrs *xattrs,
125 struct simple_xattr *new_xattr);
126
127 #endif /* _LINUX_XATTR_H */
128