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(_LIBCPP_USING_WIN32_RANDOM)
11 // Must be defined before including stdlib.h to enable rand_s().
12 #define _CRT_RAND_S
13 #endif // defined(_LIBCPP_USING_WIN32_RANDOM)
14
15 #include "random"
16 #include "system_error"
17
18 #if defined(__sun__)
19 #define rename solaris_headers_are_broken
20 #endif // defined(__sun__)
21
22 #include <errno.h>
23 #include <stdio.h>
24 #include <stdlib.h>
25
26 #if defined(_LIBCPP_USING_DEV_RANDOM)
27 #include <fcntl.h>
28 #include <unistd.h>
29 #elif defined(_LIBCPP_USING_NACL_RANDOM)
30 #include <nacl/nacl_random.h>
31 #endif
32
33
34 _LIBCPP_BEGIN_NAMESPACE_STD
35
36 #if defined(_LIBCPP_USING_ARC4_RANDOM)
37
random_device(const string & __token)38 random_device::random_device(const string& __token)
39 {
40 if (__token != "/dev/urandom")
41 __throw_system_error(ENOENT, ("random device not supported " + __token).c_str());
42 }
43
~random_device()44 random_device::~random_device()
45 {
46 }
47
48 unsigned
operator ()()49 random_device::operator()()
50 {
51 return arc4random();
52 }
53
54 #elif defined(_LIBCPP_USING_DEV_RANDOM)
55
56 random_device::random_device(const string& __token)
57 : __f_(open(__token.c_str(), O_RDONLY))
58 {
59 if (__f_ < 0)
60 __throw_system_error(errno, ("random_device failed to open " + __token).c_str());
61 }
62
63 random_device::~random_device()
64 {
65 close(__f_);
66 }
67
68 unsigned
69 random_device::operator()()
70 {
71 unsigned r;
72 size_t n = sizeof(r);
73 char* p = reinterpret_cast<char*>(&r);
74 while (n > 0)
75 {
76 ssize_t s = read(__f_, p, n);
77 if (s == 0)
78 __throw_system_error(ENODATA, "random_device got EOF");
79 if (s == -1)
80 {
81 if (errno != EINTR)
82 __throw_system_error(errno, "random_device got an unexpected error");
83 continue;
84 }
85 n -= static_cast<size_t>(s);
86 p += static_cast<size_t>(s);
87 }
88 return r;
89 }
90
91 #elif defined(_LIBCPP_USING_NACL_RANDOM)
92
93 random_device::random_device(const string& __token)
94 {
95 if (__token != "/dev/urandom")
96 __throw_system_error(ENOENT, ("random device not supported " + __token).c_str());
97 int error = nacl_secure_random_init();
98 if (error)
99 __throw_system_error(error, ("random device failed to open " + __token).c_str());
100 }
101
102 random_device::~random_device()
103 {
104 }
105
106 unsigned
107 random_device::operator()()
108 {
109 unsigned r;
110 size_t n = sizeof(r);
111 size_t bytes_written;
112 int error = nacl_secure_random(&r, n, &bytes_written);
113 if (error != 0)
114 __throw_system_error(error, "random_device failed getting bytes");
115 else if (bytes_written != n)
116 __throw_runtime_error("random_device failed to obtain enough bytes");
117 return r;
118 }
119
120 #elif defined(_LIBCPP_USING_WIN32_RANDOM)
121
122 random_device::random_device(const string& __token)
123 {
124 if (__token != "/dev/urandom")
125 __throw_system_error(ENOENT, ("random device not supported " + __token).c_str());
126 }
127
128 random_device::~random_device()
129 {
130 }
131
132 unsigned
133 random_device::operator()()
134 {
135 unsigned r;
136 errno_t err = rand_s(&r);
137 if (err)
138 __throw_system_error(err, "random_device rand_s failed.");
139 return r;
140 }
141
142 #else
143 #error "Random device not implemented for this architecture"
144 #endif
145
146 double
entropy() const147 random_device::entropy() const _NOEXCEPT
148 {
149 return 0;
150 }
151
152 _LIBCPP_END_NAMESPACE_STD
153