1//===-------------------------- random.cpp --------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#include <__config>
10
11#if defined(_LIBCPP_USING_WIN32_RANDOM)
12// Must be defined before including stdlib.h to enable rand_s().
13#define _CRT_RAND_S
14#endif // defined(_LIBCPP_USING_WIN32_RANDOM)
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
23#include <errno.h>
24#include <stdio.h>
25#include <stdlib.h>
26
27#if defined(_LIBCPP_USING_GETENTROPY)
28#include <sys/random.h>
29#elif defined(_LIBCPP_USING_DEV_RANDOM)
30#include <fcntl.h>
31#include <unistd.h>
32#elif defined(_LIBCPP_USING_NACL_RANDOM)
33#include <nacl/nacl_random.h>
34#endif
35
36
37_LIBCPP_BEGIN_NAMESPACE_STD
38
39#if defined(_LIBCPP_USING_GETENTROPY)
40
41random_device::random_device(const string& __token)
42{
43 if (__token != "/dev/urandom")
44 __throw_system_error(ENOENT, ("random device not supported " + __token).c_str());
45}
46
47random_device::~random_device()
48{
49}
50
51unsigned
52random_device::operator()()
53{
54 unsigned r;
55 size_t n = sizeof(r);
56 int err = getentropy(&r, n);
57 if (err)
58 __throw_system_error(errno, "random_device getentropy failed");
59 return r;
60}
61
62#elif defined(_LIBCPP_USING_ARC4_RANDOM)
63
64random_device::random_device(const string& __token)
65{
66 if (__token != "/dev/urandom")
67 __throw_system_error(ENOENT, ("random device not supported " + __token).c_str());
68}
69
70random_device::~random_device()
71{
72}
73
74unsigned
75random_device::operator()()
76{
77 return arc4random();
78}
79
80#elif defined(_LIBCPP_USING_DEV_RANDOM)
81
82random_device::random_device(const string& __token)
83 : __f_(open(__token.c_str(), O_RDONLY))
84{
85 if (__f_ < 0)
86 __throw_system_error(errno, ("random_device failed to open " + __token).c_str());
87}
88
89random_device::~random_device()
90{
91 close(__f_);
92}
93
94unsigned
95random_device::operator()()
96{
97 unsigned r;
98 size_t n = sizeof(r);
99 char* p = reinterpret_cast<char*>(&r);
100 while (n > 0)
101 {
102 ssize_t s = read(__f_, p, n);
103 if (s == 0)
104 __throw_system_error(ENODATA, "random_device got EOF");
105 if (s == -1)
106 {
107 if (errno != EINTR)
108 __throw_system_error(errno, "random_device got an unexpected error");
109 continue;
110 }
111 n -= static_cast<size_t>(s);
112 p += static_cast<size_t>(s);
113 }
114 return r;
115}
116
117#elif defined(_LIBCPP_USING_NACL_RANDOM)
118
119random_device::random_device(const string& __token)
120{
121 if (__token != "/dev/urandom")
122 __throw_system_error(ENOENT, ("random device not supported " + __token).c_str());
123 int error = nacl_secure_random_init();
124 if (error)
125 __throw_system_error(error, ("random device failed to open " + __token).c_str());
126}
127
128random_device::~random_device()
129{
130}
131
132unsigned
133random_device::operator()()
134{
135 unsigned r;
136 size_t n = sizeof(r);
137 size_t bytes_written;
138 int error = nacl_secure_random(&r, n, &bytes_written);
139 if (error != 0)
140 __throw_system_error(error, "random_device failed getting bytes");
141 else if (bytes_written != n)
142 __throw_runtime_error("random_device failed to obtain enough bytes");
143 return r;
144}
145
146#elif defined(_LIBCPP_USING_WIN32_RANDOM)
147
148random_device::random_device(const string& __token)
149{
150 if (__token != "/dev/urandom")
151 __throw_system_error(ENOENT, ("random device not supported " + __token).c_str());
152}
153
154random_device::~random_device()
155{
156}
157
158unsigned
159random_device::operator()()
160{
161 unsigned r;
162 errno_t err = rand_s(&r);
163 if (err)
164 __throw_system_error(err, "random_device rand_s failed.");
165 return r;
166}
167
168#else
169#error "Random device not implemented for this architecture"
170#endif
171
172double
173random_device::entropy() const _NOEXCEPT
174{
175 return 0;
176}
177
178_LIBCPP_END_NAMESPACE_STD
179