[PATCH] D23671: libLLVMSupport: Generate random block of arbitrary size

[Eugene Leviant via llvm-commits]

evgeny777 removed rL LLVM as the repository for this revision.
evgeny777 updated this revision to Diff 68707.
evgeny777 added a comment.

Added additional error checking


https://reviews.llvm.org/D23671

Files:
  RandomNumberGenerator.cpp
  Unix/Unix.h

Index: Unix/Unix.h
===================================================================
--- Unix/Unix.h
+++ Unix/Unix.h
@@ -48,6 +48,10 @@
 # include <dlfcn.h>
 #endif
 
+#ifdef HAVE_FCNTL_H
+#include <fcntl.h>
+#endif
+
 /// This function builds an error message into \p ErrMsg using the \p prefix
 /// string and the Unix error number given by \p errnum. If errnum is -1, the
 /// default then the value of errno is used.
Index: RandomNumberGenerator.cpp
===================================================================
--- RandomNumberGenerator.cpp
+++ 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 getRandomBytes(void *Buffer, size_t Size) {
+#ifdef LLVM_ON_WIN32
+  HCRYPTPROV hProvider;
+  if (CryptAcquireContextW(&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
+}


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