1/*
2 * Copyright (C) 2011 Google Inc.
3 * Copyright (C) 2017 Yusuke Suzuki <[email protected]>
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY GOOGLE, INC. ``AS IS'' AND ANY
15 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
17 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
18 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
19 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
20 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
21 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
22 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
24 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27#pragma once
28
29#include <wtf/Noncopyable.h>
30#include <wtf/StdLibExtras.h>
31
32namespace WTF {
33
34class RandomDevice {
35 WTF_MAKE_NONCOPYABLE(RandomDevice);
36public:
37#if OS(DARWIN) || OS(FUCHSIA) || OS(WINDOWS)
38 RandomDevice() = default;
39#else
40 RandomDevice();
41 ~RandomDevice();
42#endif
43
44 // This function attempts to fill buffer with randomness from the operating
45 // system. Rather than calling this function directly, consider calling
46 // cryptographicallyRandomNumber or cryptographicallyRandomValues.
47 void cryptographicallyRandomValues(unsigned char* buffer, size_t length);
48
49private:
50#if OS(DARWIN) || OS(FUCHSIA) || OS(WINDOWS)
51#elif OS(UNIX)
52 int m_fd { -1 };
53#else
54#error "This configuration doesn't have a strong source of randomness."
55// WARNING: When adding new sources of OS randomness, the randomness must
56// be of cryptographic quality!
57#endif
58};
59
60}
61