add libfuzzer custom mutator, minor enhancements and fixes

custom_mutators/libfuzzer/FuzzerIO.cpp

@@ -0,0 +1,248 @@
+//===- FuzzerIO.cpp - IO utils. -------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+// IO functions.
+//===----------------------------------------------------------------------===//
+
+#include "FuzzerDefs.h"
+#include "FuzzerExtFunctions.h"
+#include "FuzzerIO.h"
+#include "FuzzerUtil.h"
+#include <algorithm>
+#include <cstdarg>
+#include <fstream>
+#include <iterator>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+namespace fuzzer {
+
+static FILE *OutputFile = stderr;
+
+long GetEpoch(const std::string &Path) {
+
+  struct stat St;
+  if (stat(Path.c_str(), &St)) return 0;  // Can't stat, be conservative.
+  return St.st_mtime;
+
+}
+
+Unit FileToVector(const std::string &Path, size_t MaxSize, bool ExitOnError) {
+
+  std::ifstream T(Path, std::ios::binary);
+  if (ExitOnError && !T) {
+
+    Printf("No such directory: %s; exiting\n", Path.c_str());
+    exit(1);
+
+  }
+
+  T.seekg(0, T.end);
+  auto EndPos = T.tellg();
+  if (EndPos < 0) return {};
+  size_t FileLen = EndPos;
+  if (MaxSize) FileLen = std::min(FileLen, MaxSize);
+
+  T.seekg(0, T.beg);
+  Unit Res(FileLen);
+  T.read(reinterpret_cast<char *>(Res.data()), FileLen);
+  return Res;
+
+}
+
+std::string FileToString(const std::string &Path) {
+
+  std::ifstream T(Path, std::ios::binary);
+  return std::string((std::istreambuf_iterator<char>(T)),
+                     std::istreambuf_iterator<char>());
+
+}
+
+void CopyFileToErr(const std::string &Path) {
+
+  Printf("%s", FileToString(Path).c_str());
+
+}
+
+void WriteToFile(const Unit &U, const std::string &Path) {
+
+  WriteToFile(U.data(), U.size(), Path);
+
+}
+
+void WriteToFile(const std::string &Data, const std::string &Path) {
+
+  WriteToFile(reinterpret_cast<const uint8_t *>(Data.c_str()), Data.size(),
+              Path);
+
+}
+
+void WriteToFile(const uint8_t *Data, size_t Size, const std::string &Path) {
+
+  // Use raw C interface because this function may be called from a sig handler.
+  FILE *Out = fopen(Path.c_str(), "wb");
+  if (!Out) return;
+  fwrite(Data, sizeof(Data[0]), Size, Out);
+  fclose(Out);
+
+}
+
+void AppendToFile(const std::string &Data, const std::string &Path) {
+
+  AppendToFile(reinterpret_cast<const uint8_t *>(Data.data()), Data.size(),
+               Path);
+
+}
+
+void AppendToFile(const uint8_t *Data, size_t Size, const std::string &Path) {
+
+  FILE *Out = fopen(Path.c_str(), "a");
+  if (!Out) return;
+  fwrite(Data, sizeof(Data[0]), Size, Out);
+  fclose(Out);
+
+}
+
+void ReadDirToVectorOfUnits(const char *Path, Vector<Unit> *V, long *Epoch,
+                            size_t MaxSize, bool ExitOnError) {
+
+  long                E = Epoch ? *Epoch : 0;
+  Vector<std::string> Files;
+  ListFilesInDirRecursive(Path, Epoch, &Files, /*TopDir*/ true);
+  size_t NumLoaded = 0;
+  for (size_t i = 0; i < Files.size(); i++) {
+
+    auto &X = Files[i];
+    if (Epoch && GetEpoch(X) < E) continue;
+    NumLoaded++;
+    if ((NumLoaded & (NumLoaded - 1)) == 0 && NumLoaded >= 1024)
+      Printf("Loaded %zd/%zd files from %s\n", NumLoaded, Files.size(), Path);
+    auto S = FileToVector(X, MaxSize, ExitOnError);
+    if (!S.empty()) V->push_back(S);
+
+  }
+
+}
+
+void GetSizedFilesFromDir(const std::string &Dir, Vector<SizedFile> *V) {
+
+  Vector<std::string> Files;
+  ListFilesInDirRecursive(Dir, 0, &Files, /*TopDir*/ true);
+  for (auto &File : Files)
+    if (size_t Size = FileSize(File)) V->push_back({File, Size});
+
+}
+
+std::string DirPlusFile(const std::string &DirPath,
+                        const std::string &FileName) {
+
+  return DirPath + GetSeparator() + FileName;
+
+}
+
+void DupAndCloseStderr() {
+
+  int OutputFd = DuplicateFile(2);
+  if (OutputFd >= 0) {
+
+    FILE *NewOutputFile = OpenFile(OutputFd, "w");
+    if (NewOutputFile) {
+
+      OutputFile = NewOutputFile;
+      if (EF->__sanitizer_set_report_fd)
+        EF->__sanitizer_set_report_fd(
+            reinterpret_cast<void *>(GetHandleFromFd(OutputFd)));
+      DiscardOutput(2);
+
+    }
+
+  }
+
+}
+
+void CloseStdout() {
+
+  DiscardOutput(1);
+
+}
+
+void Printf(const char *Fmt, ...) {
+
+  va_list ap;
+  va_start(ap, Fmt);
+  vfprintf(OutputFile, Fmt, ap);
+  va_end(ap);
+  fflush(OutputFile);
+
+}
+
+void VPrintf(bool Verbose, const char *Fmt, ...) {
+
+  if (!Verbose) return;
+  va_list ap;
+  va_start(ap, Fmt);
+  vfprintf(OutputFile, Fmt, ap);
+  va_end(ap);
+  fflush(OutputFile);
+
+}
+
+static bool MkDirRecursiveInner(const std::string &Leaf) {
+
+  // Prevent chance of potential infinite recursion
+  if (Leaf == ".") return true;
+
+  const std::string &Dir = DirName(Leaf);
+
+  if (IsDirectory(Dir)) {
+
+    MkDir(Leaf);
+    return IsDirectory(Leaf);
+
+  }
+
+  bool ret = MkDirRecursiveInner(Dir);
+  if (!ret) {
+
+    // Give up early if a previous MkDir failed
+    return ret;
+
+  }
+
+  MkDir(Leaf);
+  return IsDirectory(Leaf);
+
+}
+
+bool MkDirRecursive(const std::string &Dir) {
+
+  if (Dir.empty()) return false;
+
+  if (IsDirectory(Dir)) return true;
+
+  return MkDirRecursiveInner(Dir);
+
+}
+
+void RmDirRecursive(const std::string &Dir) {
+
+  IterateDirRecursive(
+      Dir, [](const std::string &Path) {},
+      [](const std::string &Path) { RmDir(Path); },
+      [](const std::string &Path) { RemoveFile(Path); });
+
+}
+
+std::string TempPath(const char *Prefix, const char *Extension) {
+
+  return DirPlusFile(TmpDir(), std::string("libFuzzerTemp.") + Prefix +
+                                   std::to_string(GetPid()) + Extension);
+
+}
+
+}  // namespace fuzzer
+