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 #include <__config>
11
12 #if defined(_LIBCPP_USING_WIN32_RANDOM)
13 // Must be defined before including stdlib.h to enable rand_s().
14 #define _CRT_RAND_S
15 #endif // defined(_LIBCPP_USING_WIN32_RANDOM)
16
17 #include "random"
18 #include "system_error"
19
20 #if defined(__sun__)
21 #define rename solaris_headers_are_broken
22 #endif // defined(__sun__)
23
24 #include <errno.h>
25 #include <stdio.h>
26 #include <stdlib.h>
27
28 #if defined(_LIBCPP_USING_DEV_RANDOM)
29 #include <fcntl.h>
30 #include <unistd.h>
31 #elif defined(_LIBCPP_USING_NACL_RANDOM)
32 #include <nacl/nacl_random.h>
33 #endif
34
35
36 _LIBCPP_BEGIN_NAMESPACE_STD
37
38 #if defined(_LIBCPP_USING_ARC4_RANDOM)
39
random_device(const string & __token)40 random_device::random_device(const string& __token)
41 {
42 if (__token != "/dev/urandom")
43 __throw_system_error(ENOENT, ("random device not supported " + __token).c_str());
44 }
45
~random_device()46 random_device::~random_device()
47 {
48 }
49
50 unsigned
operator ()()51 random_device::operator()()
52 {
53 return arc4random();
54 }
55
56 #elif defined(_LIBCPP_USING_DEV_RANDOM)
57
58 random_device::random_device(const string& __token)
59 : __f_(open(__token.c_str(), O_RDONLY))
60 {
61 if (__f_ < 0)
62 __throw_system_error(errno, ("random_device failed to open " + __token).c_str());
63 }
64
65 random_device::~random_device()
66 {
67 close(__f_);
68 }
69
70 unsigned
71 random_device::operator()()
72 {
73 unsigned r;
74 size_t n = sizeof(r);
75 char* p = reinterpret_cast<char*>(&r);
76 while (n > 0)
77 {
78 ssize_t s = read(__f_, p, n);
79 if (s == 0)
80 __throw_system_error(ENODATA, "random_device got EOF");
81 if (s == -1)
82 {
83 if (errno != EINTR)
84 __throw_system_error(errno, "random_device got an unexpected error");
85 continue;
86 }
87 n -= static_cast<size_t>(s);
88 p += static_cast<size_t>(s);
89 }
90 return r;
91 }
92
93 #elif defined(_LIBCPP_USING_NACL_RANDOM)
94
95 random_device::random_device(const string& __token)
96 {
97 if (__token != "/dev/urandom")
98 __throw_system_error(ENOENT, ("random device not supported " + __token).c_str());
99 int error = nacl_secure_random_init();
100 if (error)
101 __throw_system_error(error, ("random device failed to open " + __token).c_str());
102 }
103
104 random_device::~random_device()
105 {
106 }
107
108 unsigned
109 random_device::operator()()
110 {
111 unsigned r;
112 size_t n = sizeof(r);
113 size_t bytes_written;
114 int error = nacl_secure_random(&r, n, &bytes_written);
115 if (error != 0)
116 __throw_system_error(error, "random_device failed getting bytes");
117 else if (bytes_written != n)
118 __throw_runtime_error("random_device failed to obtain enough bytes");
119 return r;
120 }
121
122 #elif defined(_LIBCPP_USING_WIN32_RANDOM)
123
124 random_device::random_device(const string& __token)
125 {
126 if (__token != "/dev/urandom")
127 __throw_system_error(ENOENT, ("random device not supported " + __token).c_str());
128 }
129
130 random_device::~random_device()
131 {
132 }
133
134 unsigned
135 random_device::operator()()
136 {
137 unsigned r;
138 errno_t err = rand_s(&r);
139 if (err)
140 __throw_system_error(err, "random_device rand_s failed.");
141 return r;
142 }
143
144 #else
145 #error "Random device not implemented for this architecture"
146 #endif
147
148 double
entropy() const149 random_device::entropy() const _NOEXCEPT
150 {
151 return 0;
152 }
153
154 _LIBCPP_END_NAMESPACE_STD
155