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
random_device(const string & __token)41 random_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
~random_device()47 random_device::~random_device()
48 {
49 }
50
51 unsigned
operator ()()52 random_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
64 random_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
70 random_device::~random_device()
71 {
72 }
73
74 unsigned
75 random_device::operator()()
76 {
77 return arc4random();
78 }
79
80 #elif defined(_LIBCPP_USING_DEV_RANDOM)
81
82 random_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
89 random_device::~random_device()
90 {
91 close(__f_);
92 }
93
94 unsigned
95 random_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
119 random_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
128 random_device::~random_device()
129 {
130 }
131
132 unsigned
133 random_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
148 random_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
154 random_device::~random_device()
155 {
156 }
157
158 unsigned
159 random_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
172 double
entropy() const173 random_device::entropy() const _NOEXCEPT
174 {
175 return 0;
176 }
177
178 _LIBCPP_END_NAMESPACE_STD
179