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 
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 
44 random_device::~random_device()
45 {
46 }
47 
48 unsigned
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
147 random_device::entropy() const _NOEXCEPT
148 {
149     return 0;
150 }
151 
152 _LIBCPP_END_NAMESPACE_STD
153