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/* List of all open_how "versions". */
23#define XATTR_ARGS_SIZE_VER0 16 /* sizeof first published struct */
24#define XATTR_ARGS_SIZE_LATEST XATTR_ARGS_SIZE_VER0
25
26struct inode;
27struct dentry;
28
29static inline bool is_posix_acl_xattr(const char *name)
30{
31 return (strcmp(name, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
32 (strcmp(name, XATTR_NAME_POSIX_ACL_DEFAULT) == 0);
33}
34
35/*
36 * struct xattr_handler: When @name is set, match attributes with exactly that
37 * name. When @prefix is set instead, match attributes with that prefix and
38 * with a non-empty suffix.
39 */
40struct xattr_handler {
41 const char *name;
42 const char *prefix;
43 int flags; /* fs private flags */
44 bool (*list)(struct dentry *dentry);
45 int (*get)(const struct xattr_handler *, struct dentry *dentry,
46 struct inode *inode, const char *name, void *buffer,
47 size_t size);
48 int (*set)(const struct xattr_handler *,
49 struct mnt_idmap *idmap, struct dentry *dentry,
50 struct inode *inode, const char *name, const void *buffer,
51 size_t size, int flags);
52};
53
54/**
55 * xattr_handler_can_list - check whether xattr can be listed
56 * @handler: handler for this type of xattr
57 * @dentry: dentry whose inode xattr to list
58 *
59 * Determine whether the xattr associated with @dentry can be listed given
60 * @handler.
61 *
62 * Return: true if xattr can be listed, false if not.
63 */
64static inline bool xattr_handler_can_list(const struct xattr_handler *handler,
65 struct dentry *dentry)
66{
67 return handler && (!handler->list || handler->list(dentry));
68}
69
70const char *xattr_full_name(const struct xattr_handler *, const char *);
71
72struct xattr {
73 const char *name;
74 void *value;
75 size_t value_len;
76};
77
78ssize_t __vfs_getxattr(struct dentry *, struct inode *, const char *, void *, size_t);
79ssize_t vfs_getxattr(struct mnt_idmap *, struct dentry *, const char *,
80 void *, size_t);
81ssize_t vfs_listxattr(struct dentry *d, char *list, size_t size);
82int __vfs_setxattr(struct mnt_idmap *, struct dentry *, struct inode *,
83 const char *, const void *, size_t, int);
84int __vfs_setxattr_noperm(struct mnt_idmap *, struct dentry *,
85 const char *, const void *, size_t, int);
86int __vfs_setxattr_locked(struct mnt_idmap *, struct dentry *,
87 const char *, const void *, size_t, int,
88 struct inode **);
89int vfs_setxattr(struct mnt_idmap *, struct dentry *, const char *,
90 const void *, size_t, int);
91int __vfs_removexattr(struct mnt_idmap *, struct dentry *, const char *);
92int __vfs_removexattr_locked(struct mnt_idmap *, struct dentry *,
93 const char *, struct inode **);
94int vfs_removexattr(struct mnt_idmap *, struct dentry *, const char *);
95
96ssize_t generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size);
97int vfs_getxattr_alloc(struct mnt_idmap *idmap,
98 struct dentry *dentry, const char *name,
99 char **xattr_value, size_t size, gfp_t flags);
100
101int xattr_supports_user_prefix(struct inode *inode);
102
103static inline const char *xattr_prefix(const struct xattr_handler *handler)
104{
105 return handler->prefix ?: handler->name;
106}
107
108struct simple_xattrs {
109 struct rb_root rb_root;
110 rwlock_t lock;
111};
112
113struct simple_xattr {
114 struct rb_node rb_node;
115 char *name;
116 size_t size;
117 char value[];
118};
119
120void simple_xattrs_init(struct simple_xattrs *xattrs);
121void simple_xattrs_free(struct simple_xattrs *xattrs, size_t *freed_space);
122size_t simple_xattr_space(const char *name, size_t size);
123struct simple_xattr *simple_xattr_alloc(const void *value, size_t size);
124void simple_xattr_free(struct simple_xattr *xattr);
125int simple_xattr_get(struct simple_xattrs *xattrs, const char *name,
126 void *buffer, size_t size);
127struct simple_xattr *simple_xattr_set(struct simple_xattrs *xattrs,
128 const char *name, const void *value,
129 size_t size, int flags);
130ssize_t simple_xattr_list(struct inode *inode, struct simple_xattrs *xattrs,
131 char *buffer, size_t size);
132void simple_xattr_add(struct simple_xattrs *xattrs,
133 struct simple_xattr *new_xattr);
134int xattr_list_one(char **buffer, ssize_t *remaining_size, const char *name);
135
136#endif /* _LINUX_XATTR_H */
137

source code of linux/include/linux/xattr.h

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