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
is_posix_acl_xattr(const char * name)25 static inline bool is_posix_acl_xattr(const char *name)
26 {
27 return (strcmp(name, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
28 (strcmp(name, XATTR_NAME_POSIX_ACL_DEFAULT) == 0);
29 }
30
31 /*
32 * struct xattr_handler: When @name is set, match attributes with exactly that
33 * name. When @prefix is set instead, match attributes with that prefix and
34 * with a non-empty suffix.
35 */
36 struct xattr_handler {
37 const char *name;
38 const char *prefix;
39 int flags; /* fs private flags */
40 bool (*list)(struct dentry *dentry);
41 int (*get)(const struct xattr_handler *, struct dentry *dentry,
42 struct inode *inode, const char *name, void *buffer,
43 size_t size);
44 int (*set)(const struct xattr_handler *,
45 struct mnt_idmap *idmap, struct dentry *dentry,
46 struct inode *inode, const char *name, const void *buffer,
47 size_t size, int flags);
48 };
49
50 /**
51 * xattr_handler_can_list - check whether xattr can be listed
52 * @handler: handler for this type of xattr
53 * @dentry: dentry whose inode xattr to list
54 *
55 * Determine whether the xattr associated with @dentry can be listed given
56 * @handler.
57 *
58 * Return: true if xattr can be listed, false if not.
59 */
xattr_handler_can_list(const struct xattr_handler * handler,struct dentry * dentry)60 static inline bool xattr_handler_can_list(const struct xattr_handler *handler,
61 struct dentry *dentry)
62 {
63 return handler && (!handler->list || handler->list(dentry));
64 }
65
66 const char *xattr_full_name(const struct xattr_handler *, const char *);
67
68 struct xattr {
69 const char *name;
70 void *value;
71 size_t value_len;
72 };
73
74 ssize_t __vfs_getxattr(struct dentry *, struct inode *, const char *, void *, size_t);
75 ssize_t vfs_getxattr(struct mnt_idmap *, struct dentry *, const char *,
76 void *, size_t);
77 ssize_t vfs_listxattr(struct dentry *d, char *list, size_t size);
78 int __vfs_setxattr(struct mnt_idmap *, struct dentry *, struct inode *,
79 const char *, const void *, size_t, int);
80 int __vfs_setxattr_noperm(struct mnt_idmap *, struct dentry *,
81 const char *, const void *, size_t, int);
82 int __vfs_setxattr_locked(struct mnt_idmap *, struct dentry *,
83 const char *, const void *, size_t, int,
84 struct inode **);
85 int vfs_setxattr(struct mnt_idmap *, struct dentry *, const char *,
86 const void *, size_t, int);
87 int __vfs_removexattr(struct mnt_idmap *, struct dentry *, const char *);
88 int __vfs_removexattr_locked(struct mnt_idmap *, struct dentry *,
89 const char *, struct inode **);
90 int vfs_removexattr(struct mnt_idmap *, struct dentry *, const char *);
91
92 ssize_t generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size);
93 int vfs_getxattr_alloc(struct mnt_idmap *idmap,
94 struct dentry *dentry, const char *name,
95 char **xattr_value, size_t size, gfp_t flags);
96
97 int xattr_supports_user_prefix(struct inode *inode);
98
xattr_prefix(const struct xattr_handler * handler)99 static inline const char *xattr_prefix(const struct xattr_handler *handler)
100 {
101 return handler->prefix ?: handler->name;
102 }
103
104 struct simple_xattrs {
105 struct rb_root rb_root;
106 rwlock_t lock;
107 };
108
109 struct simple_xattr {
110 struct rb_node rb_node;
111 char *name;
112 size_t size;
113 char value[];
114 };
115
116 void simple_xattrs_init(struct simple_xattrs *xattrs);
117 void simple_xattrs_free(struct simple_xattrs *xattrs, size_t *freed_space);
118 size_t simple_xattr_space(const char *name, size_t size);
119 struct simple_xattr *simple_xattr_alloc(const void *value, size_t size);
120 void simple_xattr_free(struct simple_xattr *xattr);
121 int simple_xattr_get(struct simple_xattrs *xattrs, const char *name,
122 void *buffer, size_t size);
123 struct simple_xattr *simple_xattr_set(struct simple_xattrs *xattrs,
124 const char *name, const void *value,
125 size_t size, int flags);
126 ssize_t simple_xattr_list(struct inode *inode, struct simple_xattrs *xattrs,
127 char *buffer, size_t size);
128 void simple_xattr_add(struct simple_xattrs *xattrs,
129 struct simple_xattr *new_xattr);
130 int xattr_list_one(char **buffer, ssize_t *remaining_size, const char *name);
131
132 #endif /* _LINUX_XATTR_H */
133