1//===-------------------------- random.cpp --------------------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is dual licensed under the MIT and the University of Illinois Open
6// Source Licenses. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9
10#if defined(_WIN32)
11// Must be defined before including stdlib.h to enable rand_s().
12#define _CRT_RAND_S
13#include <stdio.h>
14#endif // defined(_WIN32)
15
16#include "random"
17#include "system_error"
18
19#if defined(__sun__)
20#define rename solaris_headers_are_broken
21#endif // defined(__sun__)
22#if !defined(_WIN32)
23#include <fcntl.h>
24#include <unistd.h>
25#endif // !defined(_WIN32)
26#include <errno.h>
27#if defined(_LIBCPP_USING_NACL_RANDOM)
28#include <nacl/nacl_random.h>
29#endif // defined(_LIBCPP_USING_NACL_RANDOM)
30
31_LIBCPP_BEGIN_NAMESPACE_STD
32
33#if defined(_WIN32)
34
35random_device::random_device(const string&)
36{
37}
38
39random_device::~random_device()
40{
41}
42
43unsigned
44random_device::operator()()
45{
46    unsigned r;
47    errno_t err = rand_s(&r);
48    if (err)
49        __throw_system_error(err, "random_device rand_s failed.");
50    return r;
51}
52
53#elif defined(_LIBCPP_USING_NACL_RANDOM)
54
55random_device::random_device(const string& __token)
56{
57    if (__token != "/dev/urandom")
58        __throw_system_error(ENOENT, ("random device not supported " + __token).c_str());
59    int error = nacl_secure_random_init();
60    if (error)
61        __throw_system_error(error, ("random device failed to open " + __token).c_str());
62}
63
64random_device::~random_device()
65{
66}
67
68unsigned
69random_device::operator()()
70{
71    unsigned r;
72    size_t n = sizeof(r);
73    char* p = reinterpret_cast<char*>(&r);
74    size_t bytes_written;
75    int error = nacl_secure_random(&r, n, &bytes_written);
76    if (error != 0)
77        __throw_system_error(error, "random_device failed getting bytes");
78    else if (bytes_written != n)
79        __throw_runtime_error("random_device failed to obtain enough bytes");
80    return r;
81}
82
83#else // !defined(_WIN32) && !defined(_LIBCPP_USING_NACL_RANDOM)
84
85random_device::random_device(const string& __token)
86    : __f_(open(__token.c_str(), O_RDONLY))
87{
88    if (__f_ < 0)
89        __throw_system_error(errno, ("random_device failed to open " + __token).c_str());
90}
91
92random_device::~random_device()
93{
94    close(__f_);
95}
96
97unsigned
98random_device::operator()()
99{
100    unsigned r;
101    size_t n = sizeof(r);
102    char* p = reinterpret_cast<char*>(&r);
103    while (n > 0)
104    {
105        ssize_t s = read(__f_, p, n);
106        if (s == 0)
107            __throw_system_error(ENODATA, "random_device got EOF");
108        if (s == -1)
109        {
110            if (errno != EINTR)
111                __throw_system_error(errno, "random_device got an unexpected error");
112            continue;
113        }
114        n -= static_cast<size_t>(s);
115        p += static_cast<size_t>(s);
116    }
117    return r;
118}
119
120#endif // defined(_WIN32) || defined(_LIBCPP_USING_NACL_RANDOM)
121
122double
123random_device::entropy() const _NOEXCEPT
124{
125    return 0;
126}
127
128_LIBCPP_END_NAMESPACE_STD
129