Implement getRandomBytes() function
This function allows getting arbitrary sized block of random bytes.
Primary motivation is support for --build-id=uuid in lld.
Differential revision: https://reviews.llvm.org/D23671
llvm-svn: 279807
diff --git a/llvm/lib/Support/RandomNumberGenerator.cpp b/llvm/lib/Support/RandomNumberGenerator.cpp
index 81d0411..087c671 100644
--- a/llvm/lib/Support/RandomNumberGenerator.cpp
+++ b/llvm/lib/Support/RandomNumberGenerator.cpp
@@ -17,6 +17,11 @@
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
+#ifdef LLVM_ON_WIN32
+#include "Windows/WindowsSupport.h"
+#else
+#include "Unix/Unix.h"
+#endif
using namespace llvm;
@@ -55,3 +60,32 @@
uint_fast64_t RandomNumberGenerator::operator()() {
return Generator();
}
+
+// Get random vector of specified size
+std::error_code llvm::getRandomBytes(void *Buffer, size_t Size) {
+#ifdef LLVM_ON_WIN32
+ HCRYPTPROV hProvider;
+ if (CryptAcquireContext(&hProvider, 0, 0, PROV_RSA_FULL,
+ CRYPT_VERIFYCONTEXT | CRYPT_SILENT)) {
+ ScopedCryptContext ScopedHandle(hProvider);
+ if (CryptGenRandom(hProvider, Size, static_cast<BYTE *>(Buffer)))
+ return std::error_code();
+ }
+ return std::error_code(GetLastError(), std::system_category());
+#else
+ int Fd = open("/dev/urandom", O_RDONLY);
+ if (Fd != -1) {
+ std::error_code Ret;
+ ssize_t BytesRead = read(Fd, Buffer, Size);
+ if (BytesRead == -1)
+ Ret = std::error_code(errno, std::system_category());
+ else if (BytesRead != static_cast<ssize_t>(Size))
+ Ret = std::error_code(EIO, std::system_category());
+ if (close(Fd) == -1)
+ Ret = std::error_code(errno, std::system_category());
+
+ return Ret;
+ }
+ return std::error_code(errno, std::system_category());
+#endif
+}