1 //===-- Windows implementation of getentropy ------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #include "src/unistd/getentropy.h" 10 #include "hdr/errno_macros.h" 11 #include "src/__support/common.h" 12 #include "src/errno/libc_errno.h" 13 14 #define WIN32_LEAN_AND_MEAN 15 #include <Windows.h> 16 #include <bcrypt.h> 17 #include <ntstatus.h> 18 #pragma comment(lib, "bcrypt.lib") 19 20 namespace LIBC_NAMESPACE_DECL { 21 22 LLVM_LIBC_FUNCTION(int, getentropy, (void *buffer, size_t length)) { 23 __try { 24 // check the length limit 25 if (length > 256) 26 __leave; 27 28 NTSTATUS result = ::BCryptGenRandom(nullptr, static_cast<PUCHAR>(buffer), 29 static_cast<ULONG>(length), 30 BCRYPT_USE_SYSTEM_PREFERRED_RNG); 31 32 if (result == STATUS_SUCCESS) 33 return 0; 34 35 } __except (EXCEPTION_EXECUTE_HANDLER) { 36 // no need to handle exceptions specially 37 } 38 39 libc_errno = EIO; 40 return -1; 41 } 42 } // namespace LIBC_NAMESPACE_DECL 43