1 /* -*- Mode: C++; tab-width: 4; c-basic-offset: 4; indent-tabs-mode: nil -*- */
2 /*
3  *     Copyright 2016 Couchbase, Inc.
4  *
5  *   Licensed under the Apache License, Version 2.0 (the "License");
6  *   you may not use this file except in compliance with the License.
7  *   You may obtain a copy of the License at
8  *
9  *       http://www.apache.org/licenses/LICENSE-2.0
10  *
11  *   Unless required by applicable law or agreed to in writing, software
12  *   distributed under the License is distributed on an "AS IS" BASIS,
13  *   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14  *   See the License for the specific language governing permissions and
15  *   limitations under the License.
16  */
17 #pragma once
18 
19 #include <platform/sized_buffer.h>
20 #include <xattr/visibility.h>
21 
22 /**
23  * Validate that a key is legal according to the XATTR spec
24  *
25  * The XATTR key limitations:
26  * <ul>
27  *   <li>An XATTR consists of a key/value pair.</li>
28  *   <li>The XATTR key (X-Key) is a Modified UTF-8 string up to 16 bytes in
29  *       length.</li>
30  *   <li>X-Keys starting with the following characters are reserved and
31  *       cannot be used:
32  *       <ul>
33  *          <li>ispunct(), excluding underscore</li>
34  *          <li>iscntrl()</li>
35  *       </ul>
36  *   <li>X-Keys starting with a leading underscore ('_', 0x5F) are considered
37  *       system XATTRs and can only be accessed if the client holds the
38  *       SYSTEM_XATTR read / write privilege.</li>
39  *   <li>X-keys starting with a leading dollar sign ('$', 0x25) are considered
40  *       virtual xattrs</li>
41  * </ul>
42  *
43  * @param path The path to check
44  * @param key_length The length of the key component (out)
45  * @return true if the key part of the provided path meets the spec
46  */
47 XATTR_PUBLIC_API
48 bool is_valid_xattr_key(cb::const_char_buffer path, size_t& key_length);
49 
50 // Wrapper function if you couldn't care less about the key length
is_valid_xattr_key(cb::const_char_buffer path)51 inline bool is_valid_xattr_key(cb::const_char_buffer path) {
52     size_t len;
53     return is_valid_xattr_key(path, len);
54 }
55