external/bsd/libc++/dist/libcxx/src/random.cpp

   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