1 // random -*- C++ -*- 2 3 // Copyright (C) 2012-2013 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 #include <random> 26 27 #ifdef _GLIBCXX_USE_C99_STDINT_TR1 28 29 #if defined __i386__ || defined __x86_64__ 30 # include <cpuid.h> 31 #endif 32 33 34 namespace std _GLIBCXX_VISIBILITY(default) 35 { 36 37 namespace 38 { 39 static unsigned long 40 _M_strtoul(const std::string& __str) 41 { 42 unsigned long __ret = 5489UL; 43 if (__str != "mt19937") 44 { 45 const char* __nptr = __str.c_str(); 46 char* __endptr; 47 __ret = std::strtoul(__nptr, &__endptr, 0); 48 if (*__nptr == '\0' || *__endptr != '\0') 49 std::__throw_runtime_error(__N("random_device::_M_strtoul" 50 "(const std::string&)")); 51 } 52 return __ret; 53 } 54 55 #if (defined __i386__ || defined __x86_64__) && defined _GLIBCXX_X86_RDRAND 56 unsigned int 57 __attribute__ ((noinline)) 58 # ifndef __clang__ 59 __attribute__ ((target("rdrnd"))) 60 # endif 61 __x86_rdrand(void) 62 { 63 unsigned int retries = 100; 64 unsigned int val; 65 66 while (__builtin_ia32_rdrand32_step(&val) == 0) 67 if (--retries == 0) 68 std::__throw_runtime_error(__N("random_device::__x86_rdrand(void)")); 69 70 return val; 71 } 72 #endif 73 } 74 75 76 void 77 random_device::_M_init(const std::string& token) 78 { 79 const char *fname = token.c_str(); 80 81 if (token == "default") 82 { 83 #if (defined __i386__ || defined __x86_64__) && defined _GLIBCXX_X86_RDRAND 84 unsigned int eax, ebx, ecx, edx; 85 // Check availability of cpuid and, for now at least, also the 86 // CPU signature for Intel's 87 if (__get_cpuid_max(0, &ebx) > 0 && ebx == signature_INTEL_ebx) 88 { 89 __cpuid(1, eax, ebx, ecx, edx); 90 if (ecx & bit_RDRND) 91 { 92 _M_file = nullptr; 93 return; 94 } 95 } 96 #endif 97 98 fname = "/dev/urandom"; 99 } 100 else if (token != "/dev/urandom" && token != "/dev/random") 101 fail: 102 std::__throw_runtime_error(__N("random_device::" 103 "random_device(const std::string&)")); 104 105 _M_file = std::fopen(fname, "rb"); 106 if (! _M_file) 107 goto fail; 108 } 109 110 void 111 random_device::_M_init_pretr1(const std::string& token) 112 { 113 _M_mt.seed(_M_strtoul(token)); 114 } 115 116 void 117 random_device::_M_fini() 118 { 119 if (_M_file) 120 std::fclose(_M_file); 121 } 122 123 random_device::result_type 124 random_device::_M_getval() 125 { 126 #if (defined __i386__ || defined __x86_64__) && defined _GLIBCXX_X86_RDRAND 127 if (! _M_file) 128 return __x86_rdrand(); 129 #endif 130 131 result_type __ret; 132 std::fread(reinterpret_cast<void*>(&__ret), sizeof(result_type), 133 1, _M_file); 134 return __ret; 135 } 136 137 random_device::result_type 138 random_device::_M_getval_pretr1() 139 { 140 return _M_mt(); 141 } 142 143 template class mersenne_twister_engine< 144 uint_fast32_t, 145 32, 624, 397, 31, 146 0x9908b0dfUL, 11, 147 0xffffffffUL, 7, 148 0x9d2c5680UL, 15, 149 0xefc60000UL, 18, 1812433253UL>; 150 } 151 #endif 152