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      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_GETENTROPY)
     29 #include <sys/random.h>
     30 #elif defined(_LIBCPP_USING_DEV_RANDOM)
     31 #include <fcntl.h>
     32 #include <unistd.h>
     33 #elif defined(_LIBCPP_USING_NACL_RANDOM)
     34 #include <nacl/nacl_random.h>
     35 #endif
     36 
     37 
     38 _LIBCPP_BEGIN_NAMESPACE_STD
     39 
     40 #if defined(_LIBCPP_USING_GETENTROPY)
     41 
     42 random_device::random_device(const string& __token)
     43 {
     44     if (__token != "/dev/urandom")
     45         __throw_system_error(ENOENT, ("random device not supported " + __token).c_str());
     46 }
     47 
     48 random_device::~random_device()
     49 {
     50 }
     51 
     52 unsigned
     53 random_device::operator()()
     54 {
     55     unsigned r;
     56     size_t n = sizeof(r);
     57     int err = getentropy(&r, n);
     58     if (err)
     59         __throw_system_error(errno, "random_device getentropy failed");
     60     return r;
     61 }
     62 
     63 #elif defined(_LIBCPP_USING_ARC4_RANDOM)
     64 
     65 random_device::random_device(const string& __token)
     66 {
     67     if (__token != "/dev/urandom")
     68         __throw_system_error(ENOENT, ("random device not supported " + __token).c_str());
     69 }
     70 
     71 random_device::~random_device()
     72 {
     73 }
     74 
     75 unsigned
     76 random_device::operator()()
     77 {
     78     return arc4random();
     79 }
     80 
     81 #elif defined(_LIBCPP_USING_DEV_RANDOM)
     82 
     83 random_device::random_device(const string& __token)
     84     : __f_(open(__token.c_str(), O_RDONLY))
     85 {
     86     if (__f_ < 0)
     87         __throw_system_error(errno, ("random_device failed to open " + __token).c_str());
     88 }
     89 
     90 random_device::~random_device()
     91 {
     92     close(__f_);
     93 }
     94 
     95 unsigned
     96 random_device::operator()()
     97 {
     98     unsigned r;
     99     size_t n = sizeof(r);
    100     char* p = reinterpret_cast<char*>(&r);
    101     while (n > 0)
    102     {
    103         ssize_t s = read(__f_, p, n);
    104         if (s == 0)
    105             __throw_system_error(ENODATA, "random_device got EOF");
    106         if (s == -1)
    107         {
    108             if (errno != EINTR)
    109                 __throw_system_error(errno, "random_device got an unexpected error");
    110             continue;
    111         }
    112         n -= static_cast<size_t>(s);
    113         p += static_cast<size_t>(s);
    114     }
    115     return r;
    116 }
    117 
    118 #elif defined(_LIBCPP_USING_NACL_RANDOM)
    119 
    120 random_device::random_device(const string& __token)
    121 {
    122     if (__token != "/dev/urandom")
    123         __throw_system_error(ENOENT, ("random device not supported " + __token).c_str());
    124     int error = nacl_secure_random_init();
    125     if (error)
    126         __throw_system_error(error, ("random device failed to open " + __token).c_str());
    127 }
    128 
    129 random_device::~random_device()
    130 {
    131 }
    132 
    133 unsigned
    134 random_device::operator()()
    135 {
    136     unsigned r;
    137     size_t n = sizeof(r);
    138     size_t bytes_written;
    139     int error = nacl_secure_random(&r, n, &bytes_written);
    140     if (error != 0)
    141         __throw_system_error(error, "random_device failed getting bytes");
    142     else if (bytes_written != n)
    143         __throw_runtime_error("random_device failed to obtain enough bytes");
    144     return r;
    145 }
    146 
    147 #elif defined(_LIBCPP_USING_WIN32_RANDOM)
    148 
    149 random_device::random_device(const string& __token)
    150 {
    151     if (__token != "/dev/urandom")
    152         __throw_system_error(ENOENT, ("random device not supported " + __token).c_str());
    153 }
    154 
    155 random_device::~random_device()
    156 {
    157 }
    158 
    159 unsigned
    160 random_device::operator()()
    161 {
    162     unsigned r;
    163     errno_t err = rand_s(&r);
    164     if (err)
    165         __throw_system_error(err, "random_device rand_s failed.");
    166     return r;
    167 }
    168 
    169 #else
    170 #error "Random device not implemented for this architecture"
    171 #endif
    172 
    173 double
    174 random_device::entropy() const _NOEXCEPT
    175 {
    176     return 0;
    177 }
    178 
    179 _LIBCPP_END_NAMESPACE_STD
    180