Adding upstream version 1:115.7.0.upstream/1%115.7.0upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 888 insertions, 0 deletions

diff --git a/tools/fuzzing/libfuzzer/FuzzerDriver.cpp b/tools/fuzzing/libfuzzer/FuzzerDriver.cpp
new file mode 100644
index 0000000000..bedad16efa
--- /dev/null
+++ b/tools/fuzzing/libfuzzer/FuzzerDriver.cpp
@@ -0,0 +1,888 @@
+//===- FuzzerDriver.cpp - FuzzerDriver function and flags -----------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+// FuzzerDriver and flag parsing.
+//===----------------------------------------------------------------------===//
+
+#include "FuzzerCommand.h"
+#include "FuzzerCorpus.h"
+#include "FuzzerFork.h"
+#include "FuzzerIO.h"
+#include "FuzzerInterface.h"
+#include "FuzzerInternal.h"
+#include "FuzzerMerge.h"
+#include "FuzzerMutate.h"
+#include "FuzzerPlatform.h"
+#include "FuzzerRandom.h"
+#include "FuzzerTracePC.h"
+#include <algorithm>
+#include <atomic>
+#include <chrono>
+#include <cstdlib>
+#include <cstring>
+#include <mutex>
+#include <string>
+#include <thread>
+#include <fstream>
+
+// This function should be present in the libFuzzer so that the client
+// binary can test for its existence.
+#if LIBFUZZER_MSVC
+extern "C" void __libfuzzer_is_present() {}
+#if defined(_M_IX86) || defined(__i386__)
+#pragma comment(linker, "/include:___libfuzzer_is_present")
+#else
+#pragma comment(linker, "/include:__libfuzzer_is_present")
+#endif
+#else
+extern "C" __attribute__((used)) void __libfuzzer_is_present() {}
+#endif  // LIBFUZZER_MSVC
+
+namespace fuzzer {
+
+// Program arguments.
+struct FlagDescription {
+  const char *Name;
+  const char *Description;
+  int   Default;
+  int   *IntFlag;
+  const char **StrFlag;
+  unsigned int *UIntFlag;
+};
+
+struct {
+#define FUZZER_DEPRECATED_FLAG(Name)
+#define FUZZER_FLAG_INT(Name, Default, Description) int Name;
+#define FUZZER_FLAG_UNSIGNED(Name, Default, Description) unsigned int Name;
+#define FUZZER_FLAG_STRING(Name, Description) const char *Name;
+#include "FuzzerFlags.def"
+#undef FUZZER_DEPRECATED_FLAG
+#undef FUZZER_FLAG_INT
+#undef FUZZER_FLAG_UNSIGNED
+#undef FUZZER_FLAG_STRING
+} Flags;
+
+static const FlagDescription FlagDescriptions [] {
+#define FUZZER_DEPRECATED_FLAG(Name)                                           \
+  {#Name, "Deprecated; don't use", 0, nullptr, nullptr, nullptr},
+#define FUZZER_FLAG_INT(Name, Default, Description)                            \
+  {#Name, Description, Default, &Flags.Name, nullptr, nullptr},
+#define FUZZER_FLAG_UNSIGNED(Name, Default, Description)                       \
+  {#Name,   Description, static_cast<int>(Default),                            \
+   nullptr, nullptr, &Flags.Name},
+#define FUZZER_FLAG_STRING(Name, Description)                                  \
+  {#Name, Description, 0, nullptr, &Flags.Name, nullptr},
+#include "FuzzerFlags.def"
+#undef FUZZER_DEPRECATED_FLAG
+#undef FUZZER_FLAG_INT
+#undef FUZZER_FLAG_UNSIGNED
+#undef FUZZER_FLAG_STRING
+};
+
+static const size_t kNumFlags =
+    sizeof(FlagDescriptions) / sizeof(FlagDescriptions[0]);
+
+static Vector<std::string> *Inputs;
+static std::string *ProgName;
+
+static void PrintHelp() {
+  Printf("Usage:\n");
+  auto Prog = ProgName->c_str();
+  Printf("\nTo run fuzzing pass 0 or more directories.\n");
+  Printf("%s [-flag1=val1 [-flag2=val2 ...] ] [dir1 [dir2 ...] ]\n", Prog);
+
+  Printf("\nTo run individual tests without fuzzing pass 1 or more files:\n");
+  Printf("%s [-flag1=val1 [-flag2=val2 ...] ] file1 [file2 ...]\n", Prog);
+
+  Printf("\nFlags: (strictly in form -flag=value)\n");
+  size_t MaxFlagLen = 0;
+  for (size_t F = 0; F < kNumFlags; F++)
+    MaxFlagLen = std::max(strlen(FlagDescriptions[F].Name), MaxFlagLen);
+
+  for (size_t F = 0; F < kNumFlags; F++) {
+    const auto &D = FlagDescriptions[F];
+    if (strstr(D.Description, "internal flag") == D.Description) continue;
+    Printf(" %s", D.Name);
+    for (size_t i = 0, n = MaxFlagLen - strlen(D.Name); i < n; i++)
+      Printf(" ");
+    Printf("\t");
+    Printf("%d\t%s\n", D.Default, D.Description);
+  }
+  Printf("\nFlags starting with '--' will be ignored and "
+            "will be passed verbatim to subprocesses.\n");
+}
+
+static const char *FlagValue(const char *Param, const char *Name) {
+  size_t Len = strlen(Name);
+  if (Param[0] == '-' && strstr(Param + 1, Name) == Param + 1 &&
+      Param[Len + 1] == '=')
+      return &Param[Len + 2];
+  return nullptr;
+}
+
+// Avoid calling stol as it triggers a bug in clang/glibc build.
+static long MyStol(const char *Str) {
+  long Res = 0;
+  long Sign = 1;
+  if (*Str == '-') {
+    Str++;
+    Sign = -1;
+  }
+  for (size_t i = 0; Str[i]; i++) {
+    char Ch = Str[i];
+    if (Ch < '0' || Ch > '9')
+      return Res;
+    Res = Res * 10 + (Ch - '0');
+  }
+  return Res * Sign;
+}
+
+static bool ParseOneFlag(const char *Param) {
+  if (Param[0] != '-') return false;
+  if (Param[1] == '-') {
+    static bool PrintedWarning = false;
+    if (!PrintedWarning) {
+      PrintedWarning = true;
+      Printf("INFO: libFuzzer ignores flags that start with '--'\n");
+    }
+    for (size_t F = 0; F < kNumFlags; F++)
+      if (FlagValue(Param + 1, FlagDescriptions[F].Name))
+        Printf("WARNING: did you mean '%s' (single dash)?\n", Param + 1);
+    return true;
+  }
+  for (size_t F = 0; F < kNumFlags; F++) {
+    const char *Name = FlagDescriptions[F].Name;
+    const char *Str = FlagValue(Param, Name);
+    if (Str)  {
+      if (FlagDescriptions[F].IntFlag) {
+        int Val = MyStol(Str);
+        *FlagDescriptions[F].IntFlag = Val;
+        if (Flags.verbosity >= 2)
+          Printf("Flag: %s %d\n", Name, Val);
+        return true;
+      } else if (FlagDescriptions[F].UIntFlag) {
+        unsigned int Val = std::stoul(Str);
+        *FlagDescriptions[F].UIntFlag = Val;
+        if (Flags.verbosity >= 2)
+          Printf("Flag: %s %u\n", Name, Val);
+        return true;
+      } else if (FlagDescriptions[F].StrFlag) {
+        *FlagDescriptions[F].StrFlag = Str;
+        if (Flags.verbosity >= 2)
+          Printf("Flag: %s %s\n", Name, Str);
+        return true;
+      } else {  // Deprecated flag.
+        Printf("Flag: %s: deprecated, don't use\n", Name);
+        return true;
+      }
+    }
+  }
+  Printf("\n\nWARNING: unrecognized flag '%s'; "
+         "use -help=1 to list all flags\n\n", Param);
+  return true;
+}
+
+// We don't use any library to minimize dependencies.
+static void ParseFlags(const Vector<std::string> &Args,
+                       const ExternalFunctions *EF) {
+  for (size_t F = 0; F < kNumFlags; F++) {
+    if (FlagDescriptions[F].IntFlag)
+      *FlagDescriptions[F].IntFlag = FlagDescriptions[F].Default;
+    if (FlagDescriptions[F].UIntFlag)
+      *FlagDescriptions[F].UIntFlag =
+          static_cast<unsigned int>(FlagDescriptions[F].Default);
+    if (FlagDescriptions[F].StrFlag)
+      *FlagDescriptions[F].StrFlag = nullptr;
+  }
+
+  // Disable len_control by default, if LLVMFuzzerCustomMutator is used.
+  if (EF->LLVMFuzzerCustomMutator) {
+    Flags.len_control = 0;
+    Printf("INFO: found LLVMFuzzerCustomMutator (%p). "
+           "Disabling -len_control by default.\n", EF->LLVMFuzzerCustomMutator);
+  }
+
+  Inputs = new Vector<std::string>;
+  for (size_t A = 1; A < Args.size(); A++) {
+    if (ParseOneFlag(Args[A].c_str())) {
+      if (Flags.ignore_remaining_args)
+        break;
+      continue;
+    }
+    Inputs->push_back(Args[A]);
+  }
+}
+
+static std::mutex Mu;
+
+static void PulseThread() {
+  while (true) {
+    SleepSeconds(600);
+    std::lock_guard<std::mutex> Lock(Mu);
+    Printf("pulse...\n");
+  }
+}
+
+static void WorkerThread(const Command &BaseCmd, std::atomic<unsigned> *Counter,
+                         unsigned NumJobs, std::atomic<bool> *HasErrors) {
+  while (true) {
+    unsigned C = (*Counter)++;
+    if (C >= NumJobs) break;
+    std::string Log = "fuzz-" + std::to_string(C) + ".log";
+    Command Cmd(BaseCmd);
+    Cmd.setOutputFile(Log);
+    Cmd.combineOutAndErr();
+    if (Flags.verbosity) {
+      std::string CommandLine = Cmd.toString();
+      Printf("%s\n", CommandLine.c_str());
+    }
+    int ExitCode = ExecuteCommand(Cmd);
+    if (ExitCode != 0)
+      *HasErrors = true;
+    std::lock_guard<std::mutex> Lock(Mu);
+    Printf("================== Job %u exited with exit code %d ============\n",
+           C, ExitCode);
+    fuzzer::CopyFileToErr(Log);
+  }
+}
+
+std::string CloneArgsWithoutX(const Vector<std::string> &Args,
+                              const char *X1, const char *X2) {
+  std::string Cmd;
+  for (auto &S : Args) {
+    if (FlagValue(S.c_str(), X1) || FlagValue(S.c_str(), X2))
+      continue;
+    Cmd += S + " ";
+  }
+  return Cmd;
+}
+
+static int RunInMultipleProcesses(const Vector<std::string> &Args,
+                                  unsigned NumWorkers, unsigned NumJobs) {
+  std::atomic<unsigned> Counter(0);
+  std::atomic<bool> HasErrors(false);
+  Command Cmd(Args);
+  Cmd.removeFlag("jobs");
+  Cmd.removeFlag("workers");
+  Vector<std::thread> V;
+  std::thread Pulse(PulseThread);
+  Pulse.detach();
+  for (unsigned i = 0; i < NumWorkers; i++)
+    V.push_back(std::thread(WorkerThread, std::ref(Cmd), &Counter, NumJobs, &HasErrors));
+  for (auto &T : V)
+    T.join();
+  return HasErrors ? 1 : 0;
+}
+
+static void RssThread(Fuzzer *F, size_t RssLimitMb) {
+  while (true) {
+    SleepSeconds(1);
+    size_t Peak = GetPeakRSSMb();
+    if (Peak > RssLimitMb)
+      F->RssLimitCallback();
+  }
+}
+
+static void StartRssThread(Fuzzer *F, size_t RssLimitMb) {
+  if (!RssLimitMb)
+    return;
+  std::thread T(RssThread, F, RssLimitMb);
+  T.detach();
+}
+
+int RunOneTest(Fuzzer *F, const char *InputFilePath, size_t MaxLen) {
+  Unit U = FileToVector(InputFilePath);
+  if (MaxLen && MaxLen < U.size())
+    U.resize(MaxLen);
+  F->ExecuteCallback(U.data(), U.size());
+  F->TryDetectingAMemoryLeak(U.data(), U.size(), true);
+  return 0;
+}
+
+static bool AllInputsAreFiles() {
+  if (Inputs->empty()) return false;
+  for (auto &Path : *Inputs)
+    if (!IsFile(Path))
+      return false;
+  return true;
+}
+
+static std::string GetDedupTokenFromCmdOutput(const std::string &S) {
+  auto Beg = S.find("DEDUP_TOKEN:");
+  if (Beg == std::string::npos)
+    return "";
+  auto End = S.find('\n', Beg);
+  if (End == std::string::npos)
+    return "";
+  return S.substr(Beg, End - Beg);
+}
+
+int CleanseCrashInput(const Vector<std::string> &Args,
+                       const FuzzingOptions &Options) {
+  if (Inputs->size() != 1 || !Flags.exact_artifact_path) {
+    Printf("ERROR: -cleanse_crash should be given one input file and"
+          " -exact_artifact_path\n");
+    return 1;
+  }
+  std::string InputFilePath = Inputs->at(0);
+  std::string OutputFilePath = Flags.exact_artifact_path;
+  Command Cmd(Args);
+  Cmd.removeFlag("cleanse_crash");
+
+  assert(Cmd.hasArgument(InputFilePath));
+  Cmd.removeArgument(InputFilePath);
+
+  auto TmpFilePath = TempPath("CleanseCrashInput", ".repro");
+  Cmd.addArgument(TmpFilePath);
+  Cmd.setOutputFile(getDevNull());
+  Cmd.combineOutAndErr();
+
+  std::string CurrentFilePath = InputFilePath;
+  auto U = FileToVector(CurrentFilePath);
+  size_t Size = U.size();
+
+  const Vector<uint8_t> ReplacementBytes = {' ', 0xff};
+  for (int NumAttempts = 0; NumAttempts < 5; NumAttempts++) {
+    bool Changed = false;
+    for (size_t Idx = 0; Idx < Size; Idx++) {
+      Printf("CLEANSE[%d]: Trying to replace byte %zd of %zd\n", NumAttempts,
+             Idx, Size);
+      uint8_t OriginalByte = U[Idx];
+      if (ReplacementBytes.end() != std::find(ReplacementBytes.begin(),
+                                              ReplacementBytes.end(),
+                                              OriginalByte))
+        continue;
+      for (auto NewByte : ReplacementBytes) {
+        U[Idx] = NewByte;
+        WriteToFile(U, TmpFilePath);
+        auto ExitCode = ExecuteCommand(Cmd);
+        RemoveFile(TmpFilePath);
+        if (!ExitCode) {
+          U[Idx] = OriginalByte;
+        } else {
+          Changed = true;
+          Printf("CLEANSE: Replaced byte %zd with 0x%x\n", Idx, NewByte);
+          WriteToFile(U, OutputFilePath);
+          break;
+        }
+      }
+    }
+    if (!Changed) break;
+  }
+  return 0;
+}
+
+int MinimizeCrashInput(const Vector<std::string> &Args,
+                       const FuzzingOptions &Options) {
+  if (Inputs->size() != 1) {
+    Printf("ERROR: -minimize_crash should be given one input file\n");
+    return 1;
+  }
+  std::string InputFilePath = Inputs->at(0);
+  Command BaseCmd(Args);
+  BaseCmd.removeFlag("minimize_crash");
+  BaseCmd.removeFlag("exact_artifact_path");
+  assert(BaseCmd.hasArgument(InputFilePath));
+  BaseCmd.removeArgument(InputFilePath);
+  if (Flags.runs <= 0 && Flags.max_total_time == 0) {
+    Printf("INFO: you need to specify -runs=N or "
+           "-max_total_time=N with -minimize_crash=1\n"
+           "INFO: defaulting to -max_total_time=600\n");
+    BaseCmd.addFlag("max_total_time", "600");
+  }
+
+  BaseCmd.combineOutAndErr();
+
+  std::string CurrentFilePath = InputFilePath;
+  while (true) {
+    Unit U = FileToVector(CurrentFilePath);
+    Printf("CRASH_MIN: minimizing crash input: '%s' (%zd bytes)\n",
+           CurrentFilePath.c_str(), U.size());
+
+    Command Cmd(BaseCmd);
+    Cmd.addArgument(CurrentFilePath);
+
+    Printf("CRASH_MIN: executing: %s\n", Cmd.toString().c_str());
+    std::string CmdOutput;
+    bool Success = ExecuteCommand(Cmd, &CmdOutput);
+    if (Success) {
+      Printf("ERROR: the input %s did not crash\n", CurrentFilePath.c_str());
+      return 1;
+    }
+    Printf("CRASH_MIN: '%s' (%zd bytes) caused a crash. Will try to minimize "
+           "it further\n",
+           CurrentFilePath.c_str(), U.size());
+    auto DedupToken1 = GetDedupTokenFromCmdOutput(CmdOutput);
+    if (!DedupToken1.empty())
+      Printf("CRASH_MIN: DedupToken1: %s\n", DedupToken1.c_str());
+
+    std::string ArtifactPath =
+        Flags.exact_artifact_path
+            ? Flags.exact_artifact_path
+            : Options.ArtifactPrefix + "minimized-from-" + Hash(U);
+    Cmd.addFlag("minimize_crash_internal_step", "1");
+    Cmd.addFlag("exact_artifact_path", ArtifactPath);
+    Printf("CRASH_MIN: executing: %s\n", Cmd.toString().c_str());
+    CmdOutput.clear();
+    Success = ExecuteCommand(Cmd, &CmdOutput);
+    Printf("%s", CmdOutput.c_str());
+    if (Success) {
+      if (Flags.exact_artifact_path) {
+        CurrentFilePath = Flags.exact_artifact_path;
+        WriteToFile(U, CurrentFilePath);
+      }
+      Printf("CRASH_MIN: failed to minimize beyond %s (%d bytes), exiting\n",
+             CurrentFilePath.c_str(), U.size());
+      break;
+    }
+    auto DedupToken2 = GetDedupTokenFromCmdOutput(CmdOutput);
+    if (!DedupToken2.empty())
+      Printf("CRASH_MIN: DedupToken2: %s\n", DedupToken2.c_str());
+
+    if (DedupToken1 != DedupToken2) {
+      if (Flags.exact_artifact_path) {
+        CurrentFilePath = Flags.exact_artifact_path;
+        WriteToFile(U, CurrentFilePath);
+      }
+      Printf("CRASH_MIN: mismatch in dedup tokens"
+             " (looks like a different bug). Won't minimize further\n");
+      break;
+    }
+
+    CurrentFilePath = ArtifactPath;
+    Printf("*********************************\n");
+  }
+  return 0;
+}
+
+int MinimizeCrashInputInternalStep(Fuzzer *F, InputCorpus *Corpus) {
+  assert(Inputs->size() == 1);
+  std::string InputFilePath = Inputs->at(0);
+  Unit U = FileToVector(InputFilePath);
+  Printf("INFO: Starting MinimizeCrashInputInternalStep: %zd\n", U.size());
+  if (U.size() < 2) {
+    Printf("INFO: The input is small enough, exiting\n");
+    return 0;
+  }
+  F->SetMaxInputLen(U.size());
+  F->SetMaxMutationLen(U.size() - 1);
+  F->MinimizeCrashLoop(U);
+  Printf("INFO: Done MinimizeCrashInputInternalStep, no crashes found\n");
+  return 0;
+}
+
+int Merge(Fuzzer *F, FuzzingOptions &Options, const Vector<std::string> &Args,
+           const Vector<std::string> &Corpora, const char *CFPathOrNull) {
+  if (Corpora.size() < 2) {
+    Printf("INFO: Merge requires two or more corpus dirs\n");
+    return 0;
+  }
+
+  Vector<SizedFile> OldCorpus, NewCorpus;
+  int Res = GetSizedFilesFromDir(Corpora[0], &OldCorpus);
+  if (Res != 0)
+    return Res;
+  for (size_t i = 1; i < Corpora.size(); i++) {
+    Res = GetSizedFilesFromDir(Corpora[i], &NewCorpus);
+    if (Res != 0)
+      return Res;
+  }
+  std::sort(OldCorpus.begin(), OldCorpus.end());
+  std::sort(NewCorpus.begin(), NewCorpus.end());
+
+  std::string CFPath = CFPathOrNull ? CFPathOrNull : TempPath("Merge", ".txt");
+  Vector<std::string> NewFiles;
+  Set<uint32_t> NewFeatures, NewCov;
+  Res = CrashResistantMerge(Args, OldCorpus, NewCorpus, &NewFiles, {}, &NewFeatures,
+                      {}, &NewCov, CFPath, true);
+  if (Res != 0)
+    return Res;
+
+  if (F->isGracefulExitRequested())
+    return 0;
+  for (auto &Path : NewFiles)
+    F->WriteToOutputCorpus(FileToVector(Path, Options.MaxLen));
+  // We are done, delete the control file if it was a temporary one.
+  if (!Flags.merge_control_file)
+    RemoveFile(CFPath);
+
+  return 0;
+}
+
+int AnalyzeDictionary(Fuzzer *F, const Vector<Unit>& Dict,
+                      UnitVector& Corpus) {
+  Printf("Started dictionary minimization (up to %d tests)\n",
+         Dict.size() * Corpus.size() * 2);
+
+  // Scores and usage count for each dictionary unit.
+  Vector<int> Scores(Dict.size());
+  Vector<int> Usages(Dict.size());
+
+  Vector<size_t> InitialFeatures;
+  Vector<size_t> ModifiedFeatures;
+  for (auto &C : Corpus) {
+    // Get coverage for the testcase without modifications.
+    F->ExecuteCallback(C.data(), C.size());
+    InitialFeatures.clear();
+    TPC.CollectFeatures([&](size_t Feature) {
+      InitialFeatures.push_back(Feature);
+    });
+
+    for (size_t i = 0; i < Dict.size(); ++i) {
+      Vector<uint8_t> Data = C;
+      auto StartPos = std::search(Data.begin(), Data.end(),
+                                  Dict[i].begin(), Dict[i].end());
+      // Skip dictionary unit, if the testcase does not contain it.
+      if (StartPos == Data.end())
+        continue;
+
+      ++Usages[i];
+      while (StartPos != Data.end()) {
+        // Replace all occurrences of dictionary unit in the testcase.
+        auto EndPos = StartPos + Dict[i].size();
+        for (auto It = StartPos; It != EndPos; ++It)
+          *It ^= 0xFF;
+
+        StartPos = std::search(EndPos, Data.end(),
+                               Dict[i].begin(), Dict[i].end());
+      }
+
+      // Get coverage for testcase with masked occurrences of dictionary unit.
+      F->ExecuteCallback(Data.data(), Data.size());
+      ModifiedFeatures.clear();
+      TPC.CollectFeatures([&](size_t Feature) {
+        ModifiedFeatures.push_back(Feature);
+      });
+
+      if (InitialFeatures == ModifiedFeatures)
+        --Scores[i];
+      else
+        Scores[i] += 2;
+    }
+  }
+
+  Printf("###### Useless dictionary elements. ######\n");
+  for (size_t i = 0; i < Dict.size(); ++i) {
+    // Dictionary units with positive score are treated as useful ones.
+    if (Scores[i] > 0)
+       continue;
+
+    Printf("\"");
+    PrintASCII(Dict[i].data(), Dict[i].size(), "\"");
+    Printf(" # Score: %d, Used: %d\n", Scores[i], Usages[i]);
+  }
+  Printf("###### End of useless dictionary elements. ######\n");
+  return 0;
+}
+
+int ParseSeedInuts(const char *seed_inputs, Vector<std::string> &Files) {
+  // Parse -seed_inputs=file1,file2,... or -seed_inputs=@seed_inputs_file
+  if (!seed_inputs) return 0;
+  std::string SeedInputs;
+  if (Flags.seed_inputs[0] == '@')
+    SeedInputs = FileToString(Flags.seed_inputs + 1); // File contains list.
+  else
+    SeedInputs = Flags.seed_inputs; // seed_inputs contains the list.
+  if (SeedInputs.empty()) {
+    Printf("seed_inputs is empty or @file does not exist.\n");
+    return 1;
+  }
+  // Parse SeedInputs.
+  size_t comma_pos = 0;
+  while ((comma_pos = SeedInputs.find_last_of(',')) != std::string::npos) {
+    Files.push_back(SeedInputs.substr(comma_pos + 1));
+    SeedInputs = SeedInputs.substr(0, comma_pos);
+  }
+  Files.push_back(SeedInputs);
+  return 0;
+}
+
+static Vector<SizedFile> ReadCorpora(const Vector<std::string> &CorpusDirs,
+    const Vector<std::string> &ExtraSeedFiles) {
+  Vector<SizedFile> SizedFiles;
+  size_t LastNumFiles = 0;
+  for (auto &Dir : CorpusDirs) {
+    GetSizedFilesFromDir(Dir, &SizedFiles);
+    Printf("INFO: % 8zd files found in %s\n", SizedFiles.size() - LastNumFiles,
+           Dir.c_str());
+    LastNumFiles = SizedFiles.size();
+  }
+  for (auto &File : ExtraSeedFiles)
+    if (auto Size = FileSize(File))
+      SizedFiles.push_back({File, Size});
+  return SizedFiles;
+}
+
+int FuzzerDriver(int *argc, char ***argv, UserCallback Callback) {
+  using namespace fuzzer;
+  assert(argc && argv && "Argument pointers cannot be nullptr");
+  std::string Argv0((*argv)[0]);
+  if (!EF)
+    EF = new ExternalFunctions();
+  if (EF->LLVMFuzzerInitialize)
+    EF->LLVMFuzzerInitialize(argc, argv);
+  if (EF->__msan_scoped_disable_interceptor_checks)
+    EF->__msan_scoped_disable_interceptor_checks();
+  const Vector<std::string> Args(*argv, *argv + *argc);
+  assert(!Args.empty());
+  ProgName = new std::string(Args[0]);
+  if (Argv0 != *ProgName) {
+    Printf("ERROR: argv[0] has been modified in LLVMFuzzerInitialize\n");
+    return 1;
+  }
+  ParseFlags(Args, EF);
+  if (Flags.help) {
+    PrintHelp();
+    return 0;
+  }
+
+  if (Flags.close_fd_mask & 2)
+    DupAndCloseStderr();
+  if (Flags.close_fd_mask & 1)
+    CloseStdout();
+
+  if (Flags.jobs > 0 && Flags.workers == 0) {
+    Flags.workers = std::min(NumberOfCpuCores() / 2, Flags.jobs);
+    if (Flags.workers > 1)
+      Printf("Running %u workers\n", Flags.workers);
+  }
+
+  if (Flags.workers > 0 && Flags.jobs > 0)
+    return RunInMultipleProcesses(Args, Flags.workers, Flags.jobs);
+
+  FuzzingOptions Options;
+  Options.Verbosity = Flags.verbosity;
+  Options.MaxLen = Flags.max_len;
+  Options.LenControl = Flags.len_control;
+  Options.UnitTimeoutSec = Flags.timeout;
+  Options.ErrorExitCode = Flags.error_exitcode;
+  Options.TimeoutExitCode = Flags.timeout_exitcode;
+  Options.IgnoreTimeouts = Flags.ignore_timeouts;
+  Options.IgnoreOOMs = Flags.ignore_ooms;
+  Options.IgnoreCrashes = Flags.ignore_crashes;
+  Options.MaxTotalTimeSec = Flags.max_total_time;
+  Options.DoCrossOver = Flags.cross_over;
+  Options.MutateDepth = Flags.mutate_depth;
+  Options.ReduceDepth = Flags.reduce_depth;
+  Options.UseCounters = Flags.use_counters;
+  Options.UseMemmem = Flags.use_memmem;
+  Options.UseCmp = Flags.use_cmp;
+  Options.UseValueProfile = Flags.use_value_profile;
+  Options.Shrink = Flags.shrink;
+  Options.ReduceInputs = Flags.reduce_inputs;
+  Options.ShuffleAtStartUp = Flags.shuffle;
+  Options.PreferSmall = Flags.prefer_small;
+  Options.ReloadIntervalSec = Flags.reload;
+  Options.OnlyASCII = Flags.only_ascii;
+  Options.DetectLeaks = Flags.detect_leaks;
+  Options.PurgeAllocatorIntervalSec = Flags.purge_allocator_interval;
+  Options.TraceMalloc = Flags.trace_malloc;
+  Options.RssLimitMb = Flags.rss_limit_mb;
+  Options.MallocLimitMb = Flags.malloc_limit_mb;
+  if (!Options.MallocLimitMb)
+    Options.MallocLimitMb = Options.RssLimitMb;
+  if (Flags.runs >= 0)
+    Options.MaxNumberOfRuns = Flags.runs;
+  if (!Inputs->empty() && !Flags.minimize_crash_internal_step)
+    Options.OutputCorpus = (*Inputs)[0];
+  Options.ReportSlowUnits = Flags.report_slow_units;
+  if (Flags.artifact_prefix)
+    Options.ArtifactPrefix = Flags.artifact_prefix;
+  if (Flags.exact_artifact_path)
+    Options.ExactArtifactPath = Flags.exact_artifact_path;
+  Vector<Unit> Dictionary;
+  if (Flags.dict)
+    if (!ParseDictionaryFile(FileToString(Flags.dict), &Dictionary))
+      return 1;
+  if (Flags.verbosity > 0 && !Dictionary.empty())
+    Printf("Dictionary: %zd entries\n", Dictionary.size());
+  bool RunIndividualFiles = AllInputsAreFiles();
+  Options.SaveArtifacts =
+      !RunIndividualFiles || Flags.minimize_crash_internal_step;
+  Options.PrintNewCovPcs = Flags.print_pcs;
+  Options.PrintNewCovFuncs = Flags.print_funcs;
+  Options.PrintFinalStats = Flags.print_final_stats;
+  Options.PrintCorpusStats = Flags.print_corpus_stats;
+  Options.PrintCoverage = Flags.print_coverage;
+  if (Flags.exit_on_src_pos)
+    Options.ExitOnSrcPos = Flags.exit_on_src_pos;
+  if (Flags.exit_on_item)
+    Options.ExitOnItem = Flags.exit_on_item;
+  if (Flags.focus_function)
+    Options.FocusFunction = Flags.focus_function;
+  if (Flags.data_flow_trace)
+    Options.DataFlowTrace = Flags.data_flow_trace;
+  if (Flags.features_dir)
+    Options.FeaturesDir = Flags.features_dir;
+  if (Flags.collect_data_flow)
+    Options.CollectDataFlow = Flags.collect_data_flow;
+  if (Flags.stop_file)
+    Options.StopFile = Flags.stop_file;
+  Options.Entropic = Flags.entropic;
+  Options.EntropicFeatureFrequencyThreshold =
+      (size_t)Flags.entropic_feature_frequency_threshold;
+  Options.EntropicNumberOfRarestFeatures =
+      (size_t)Flags.entropic_number_of_rarest_features;
+  if (Options.Entropic) {
+    if (!Options.FocusFunction.empty()) {
+      Printf("ERROR: The parameters `--entropic` and `--focus_function` cannot "
+             "be used together.\n");
+      return 1;
+    }
+    Printf("INFO: Running with entropic power schedule (0x%X, %d).\n",
+           Options.EntropicFeatureFrequencyThreshold,
+           Options.EntropicNumberOfRarestFeatures);
+  }
+  struct EntropicOptions Entropic;
+  Entropic.Enabled = Options.Entropic;
+  Entropic.FeatureFrequencyThreshold =
+      Options.EntropicFeatureFrequencyThreshold;
+  Entropic.NumberOfRarestFeatures = Options.EntropicNumberOfRarestFeatures;
+
+  unsigned Seed = Flags.seed;
+  // Initialize Seed.
+  if (Seed == 0)
+    Seed =
+        std::chrono::system_clock::now().time_since_epoch().count() + GetPid();
+  if (Flags.verbosity)
+    Printf("INFO: Seed: %u\n", Seed);
+
+  if (Flags.collect_data_flow && !Flags.fork && !Flags.merge) {
+    if (RunIndividualFiles)
+      return CollectDataFlow(Flags.collect_data_flow, Flags.data_flow_trace,
+                        ReadCorpora({}, *Inputs));
+    else
+      return CollectDataFlow(Flags.collect_data_flow, Flags.data_flow_trace,
+                        ReadCorpora(*Inputs, {}));
+  }
+
+  Random Rand(Seed);
+  auto *MD = new MutationDispatcher(Rand, Options);
+  auto *Corpus = new InputCorpus(Options.OutputCorpus, Entropic);
+  auto *F = new Fuzzer(Callback, *Corpus, *MD, Options);
+
+  for (auto &U: Dictionary)
+    if (U.size() <= Word::GetMaxSize())
+      MD->AddWordToManualDictionary(Word(U.data(), U.size()));
+
+      // Threads are only supported by Chrome. Don't use them with emscripten
+      // for now.
+#if !LIBFUZZER_EMSCRIPTEN
+  StartRssThread(F, Flags.rss_limit_mb);
+#endif // LIBFUZZER_EMSCRIPTEN
+
+  Options.HandleAbrt = Flags.handle_abrt;
+  Options.HandleBus = Flags.handle_bus;
+  Options.HandleFpe = Flags.handle_fpe;
+  Options.HandleIll = Flags.handle_ill;
+  Options.HandleInt = Flags.handle_int;
+  Options.HandleSegv = Flags.handle_segv;
+  Options.HandleTerm = Flags.handle_term;
+  Options.HandleXfsz = Flags.handle_xfsz;
+  Options.HandleUsr1 = Flags.handle_usr1;
+  Options.HandleUsr2 = Flags.handle_usr2;
+  SetSignalHandler(Options);
+
+  std::atexit(Fuzzer::StaticExitCallback);
+
+  if (Flags.minimize_crash)
+    return MinimizeCrashInput(Args, Options);
+
+  if (Flags.minimize_crash_internal_step)
+    return MinimizeCrashInputInternalStep(F, Corpus);
+
+  if (Flags.cleanse_crash)
+    return CleanseCrashInput(Args, Options);
+
+  if (RunIndividualFiles) {
+    Options.SaveArtifacts = false;
+    int Runs = std::max(1, Flags.runs);
+    Printf("%s: Running %zd inputs %d time(s) each.\n", ProgName->c_str(),
+           Inputs->size(), Runs);
+    for (auto &Path : *Inputs) {
+      auto StartTime = system_clock::now();
+      Printf("Running: %s\n", Path.c_str());
+      for (int Iter = 0; Iter < Runs; Iter++)
+        RunOneTest(F, Path.c_str(), Options.MaxLen);
+      auto StopTime = system_clock::now();
+      auto MS = duration_cast<milliseconds>(StopTime - StartTime).count();
+      Printf("Executed %s in %zd ms\n", Path.c_str(), (long)MS);
+    }
+    Printf("***\n"
+           "*** NOTE: fuzzing was not performed, you have only\n"
+           "***       executed the target code on a fixed set of inputs.\n"
+           "***\n");
+    F->PrintFinalStats();
+    return 0;
+  }
+
+  if (Flags.fork)
+    return FuzzWithFork(F->GetMD().GetRand(), Options, Args, *Inputs, Flags.fork);
+
+  if (Flags.merge)
+    return Merge(F, Options, Args, *Inputs, Flags.merge_control_file);
+
+  if (Flags.merge_inner) {
+    const size_t kDefaultMaxMergeLen = 1 << 20;
+    if (Options.MaxLen == 0)
+      F->SetMaxInputLen(kDefaultMaxMergeLen);
+    assert(Flags.merge_control_file);
+    return F->CrashResistantMergeInternalStep(Flags.merge_control_file);
+  }
+
+  if (Flags.analyze_dict) {
+    size_t MaxLen = INT_MAX;  // Large max length.
+    UnitVector InitialCorpus;
+    for (auto &Inp : *Inputs) {
+      Printf("Loading corpus dir: %s\n", Inp.c_str());
+      ReadDirToVectorOfUnits(Inp.c_str(), &InitialCorpus, nullptr,
+                             MaxLen, /*ExitOnError=*/false);
+    }
+
+    if (Dictionary.empty() || Inputs->empty()) {
+      Printf("ERROR: can't analyze dict without dict and corpus provided\n");
+      return 1;
+    }
+    if (AnalyzeDictionary(F, Dictionary, InitialCorpus)) {
+      Printf("Dictionary analysis failed\n");
+      return 1;
+    }
+    Printf("Dictionary analysis succeeded\n");
+    return 0;
+  }
+
+  {
+    Vector<std::string> Files;
+    int Res = ParseSeedInuts(Flags.seed_inputs, Files);
+    if (Res != 0)
+      return Res;
+    auto CorporaFiles = ReadCorpora(*Inputs, Files);
+    Res = F->Loop(CorporaFiles);
+    if (Res != 0)
+      return Res;
+    if (F->isGracefulExitRequested())
+      return 0;
+  }
+
+  if (Flags.verbosity)
+    Printf("Done %zd runs in %zd second(s)\n", F->getTotalNumberOfRuns(),
+           F->secondsSinceProcessStartUp());
+  F->PrintFinalStats();
+
+  return 0;  // Don't let F destroy itself.
+}
+
+extern "C" ATTRIBUTE_INTERFACE int
+LLVMFuzzerRunDriver(int *argc, char ***argv,
+                    int (*UserCb)(const uint8_t *Data, size_t Size)) {
+  return FuzzerDriver(argc, argv, UserCb);
+}
+
+// Storage for global ExternalFunctions object.
+ExternalFunctions *EF = nullptr;
+
+}  // namespace fuzzer