1 // random -*- C++ -*- 2 3 // Copyright (C) 2012-2016 Free Software Foundation, Inc. 4 // 5 // This file is part of the GNU ISO C++ Library. This library is free 6 // software; you can redistribute it and/or modify it under the 7 // terms of the GNU General Public License as published by the 8 // Free Software Foundation; either version 3, or (at your option) 9 // any later version. 10 11 // This library is distributed in the hope that it will be useful, 12 // but WITHOUT ANY WARRANTY; without even the implied warranty of 13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 // GNU General Public License for more details. 15 16 // Under Section 7 of GPL version 3, you are granted additional 17 // permissions described in the GCC Runtime Library Exception, version 18 // 3.1, as published by the Free Software Foundation. 19 20 // You should have received a copy of the GNU General Public License and 21 // a copy of the GCC Runtime Library Exception along with this program; 22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 23 // <http://www.gnu.org/licenses/>. 24 25 #define _GLIBCXX_USE_CXX11_ABI 1 26 #include <random> 27 28 #ifdef _GLIBCXX_USE_C99_STDINT_TR1 29 30 #if defined __i386__ || defined __x86_64__ 31 # include <cpuid.h> 32 #endif 33 34 #include <cerrno> 35 #include <cstdio> 36 37 #ifdef _GLIBCXX_HAVE_UNISTD_H 38 # include <unistd.h> 39 #endif 40 41 namespace std _GLIBCXX_VISIBILITY(default) 42 { 43 namespace 44 { 45 static unsigned long _M_strtoul(const std::string & __str)46 _M_strtoul(const std::string& __str) 47 { 48 unsigned long __ret = 5489UL; 49 if (__str != "mt19937") 50 { 51 const char* __nptr = __str.c_str(); 52 char* __endptr; 53 __ret = std::strtoul(__nptr, &__endptr, 0); 54 if (*__nptr == '\0' || *__endptr != '\0') 55 std::__throw_runtime_error(__N("random_device::_M_strtoul" 56 "(const std::string&)")); 57 } 58 return __ret; 59 } 60 61 #if (defined __i386__ || defined __x86_64__) && defined _GLIBCXX_X86_RDRAND 62 unsigned int 63 __attribute__ ((target("rdrnd"))) __x86_rdrand(void)64 __x86_rdrand(void) 65 { 66 unsigned int retries = 100; 67 unsigned int val; 68 69 while (__builtin_ia32_rdrand32_step(&val) == 0) 70 if (--retries == 0) 71 std::__throw_runtime_error(__N("random_device::__x86_rdrand(void)")); 72 73 return val; 74 } 75 #endif 76 } 77 78 void _M_init(const std::string & token)79 random_device::_M_init(const std::string& token) 80 { 81 const char *fname = token.c_str(); 82 83 if (token == "default") 84 { 85 #if (defined __i386__ || defined __x86_64__) && defined _GLIBCXX_X86_RDRAND 86 unsigned int eax, ebx, ecx, edx; 87 // Check availability of cpuid and, for now at least, also the 88 // CPU signature for Intel's 89 if (__get_cpuid_max(0, &ebx) > 0 && ebx == signature_INTEL_ebx) 90 { 91 __cpuid(1, eax, ebx, ecx, edx); 92 if (ecx & bit_RDRND) 93 { 94 _M_file = nullptr; 95 return; 96 } 97 } 98 #endif 99 100 fname = "/dev/urandom"; 101 } 102 else if (token != "/dev/urandom" && token != "/dev/random") 103 fail: 104 std::__throw_runtime_error(__N("random_device::" 105 "random_device(const std::string&)")); 106 107 _M_file = static_cast<void*>(std::fopen(fname, "rb")); 108 if (!_M_file) 109 goto fail; 110 } 111 112 void _M_init_pretr1(const std::string & token)113 random_device::_M_init_pretr1(const std::string& token) 114 { 115 _M_mt.seed(_M_strtoul(token)); 116 } 117 118 void _M_fini()119 random_device::_M_fini() 120 { 121 if (_M_file) 122 std::fclose(static_cast<FILE*>(_M_file)); 123 } 124 125 random_device::result_type _M_getval()126 random_device::_M_getval() 127 { 128 #if (defined __i386__ || defined __x86_64__) && defined _GLIBCXX_X86_RDRAND 129 if (!_M_file) 130 return __x86_rdrand(); 131 #endif 132 133 result_type __ret; 134 void* p = &__ret; 135 size_t n = sizeof(result_type); 136 #ifdef _GLIBCXX_HAVE_UNISTD_H 137 do 138 { 139 const int e = read(fileno(static_cast<FILE*>(_M_file)), p, n); 140 if (e > 0) 141 { 142 n -= e; 143 p = static_cast<char*>(p) + e; 144 } 145 else if (e != -1 || errno != EINTR) 146 __throw_runtime_error(__N("random_device could not be read")); 147 } 148 while (n > 0); 149 #else 150 const size_t e = std::fread(p, n, 1, static_cast<FILE*>(_M_file)); 151 if (e != 1) 152 __throw_runtime_error(__N("random_device could not be read")); 153 #endif 154 155 return __ret; 156 } 157 158 random_device::result_type _M_getval_pretr1()159 random_device::_M_getval_pretr1() 160 { 161 return _M_mt(); 162 } 163 164 template class mersenne_twister_engine< 165 uint_fast32_t, 166 32, 624, 397, 31, 167 0x9908b0dfUL, 11, 168 0xffffffffUL, 7, 169 0x9d2c5680UL, 15, 170 0xefc60000UL, 18, 1812433253UL>; 171 } 172 #endif 173