Use binary write mode in WriteToFile function to avoid appended \r characters on Windows

Summary:
When using libfuzzer on Windows, in the contents of a crash sample, bytes that can be mistaken for a \n are replaced by a \r\n sequence. As a consequence, crashes are not reproducible. This patch will open files in binary mode to fix this issue. The patch does not affect POSIX systems.

Patch by tuktuk

Reviewers: kcc, vitalybuka

Reviewed By: vitalybuka

Subscribers: dexonsmith, jdoerfert, llvm-commits, #sanitizers

Tags: #llvm, #sanitizers

Differential Revision: https://reviews.llvm.org/D60008

llvm-svn: 357807

1 files changed, 24 insertions, 0 deletions

diff --git a/compiler-rt/test/fuzzer/ReloadTest.cpp b/compiler-rt/test/fuzzer/ReloadTest.cpp
new file mode 100644
index 00000000000..fb1fef97a30
--- /dev/null
+++ b/compiler-rt/test/fuzzer/ReloadTest.cpp
@@ -0,0 +1,24 @@
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+// Test that fuzzer we can reload artifacts with any bytes inside.
+#include <algorithm>
+#include <cstdint>
+#include <numeric>
+#include <set>
+#include <stdio.h>
+
+extern "C" size_t LLVMFuzzerCustomMutator(uint8_t *Data, size_t Size,
+                                          size_t MaxSize, unsigned int Seed) {
+  std::srand(Seed);
+  std::generate(Data, Data + MaxSize, std::rand);
+  return MaxSize;
+}
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  if (Size > 5000 && std::set<uint8_t>(Data, Data + Size).size() > 255 &&
+      (uint8_t)std::accumulate(Data, Data + Size, uint8_t(Size)) == 0)
+    __builtin_trap();
+  return 0;
+}