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 
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 
47 random_device::~random_device()
48 {
49 }
50 
51 unsigned
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
173 random_device::entropy() const _NOEXCEPT
174 {
175     return 0;
176 }
177 
178 _LIBCPP_END_NAMESPACE_STD
179