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 _M_strtoul(const std::string & __str)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__ ((target("rdrnd"))) __x86_rdrand(void)58 __x86_rdrand(void) 59 { 60 unsigned int retries = 100; 61 unsigned int val; 62 63 while (__builtin_ia32_rdrand32_step(&val) == 0) 64 if (--retries == 0) 65 std::__throw_runtime_error(__N("random_device::__x86_rdrand(void)")); 66 67 return val; 68 } 69 #endif 70 } 71 72 73 void _M_init(const std::string & token)74 random_device::_M_init(const std::string& token) 75 { 76 const char *fname = token.c_str(); 77 78 if (token == "default") 79 { 80 #if (defined __i386__ || defined __x86_64__) && defined _GLIBCXX_X86_RDRAND 81 unsigned int eax, ebx, ecx, edx; 82 // Check availability of cpuid and, for now at least, also the 83 // CPU signature for Intel's 84 if (__get_cpuid_max(0, &ebx) > 0 && ebx == signature_INTEL_ebx) 85 { 86 __cpuid(1, eax, ebx, ecx, edx); 87 if (ecx & bit_RDRND) 88 { 89 _M_file = nullptr; 90 return; 91 } 92 } 93 #endif 94 95 fname = "/dev/urandom"; 96 } 97 else if (token != "/dev/urandom" && token != "/dev/random") 98 fail: 99 std::__throw_runtime_error(__N("random_device::" 100 "random_device(const std::string&)")); 101 102 _M_file = std::fopen(fname, "rb"); 103 if (! _M_file) 104 goto fail; 105 } 106 107 void _M_init_pretr1(const std::string & token)108 random_device::_M_init_pretr1(const std::string& token) 109 { 110 _M_mt.seed(_M_strtoul(token)); 111 } 112 113 void _M_fini()114 random_device::_M_fini() 115 { 116 if (_M_file) 117 std::fclose(_M_file); 118 } 119 120 random_device::result_type _M_getval()121 random_device::_M_getval() 122 { 123 #if (defined __i386__ || defined __x86_64__) && defined _GLIBCXX_X86_RDRAND 124 if (! _M_file) 125 return __x86_rdrand(); 126 #endif 127 128 result_type __ret; 129 std::fread(reinterpret_cast<void*>(&__ret), sizeof(result_type), 130 1, _M_file); 131 return __ret; 132 } 133 134 random_device::result_type _M_getval_pretr1()135 random_device::_M_getval_pretr1() 136 { 137 return _M_mt(); 138 } 139 140 template class mersenne_twister_engine< 141 uint_fast32_t, 142 32, 624, 397, 31, 143 0x9908b0dfUL, 11, 144 0xffffffffUL, 7, 145 0x9d2c5680UL, 15, 146 0xefc60000UL, 18, 1812433253UL>; 147 } 148 #endif 149