1 files changed, 339 insertions, 0 deletions
diff --git a/lib/Fuzzer/FuzzerLoop.cpp b/lib/Fuzzer/FuzzerLoop.cpp
new file mode 100644
index 0000000000000..4c8b247a72ed6
--- /dev/null
+++ b/lib/Fuzzer/FuzzerLoop.cpp
@@ -0,0 +1,339 @@
+//===- FuzzerLoop.cpp - Fuzzer's main loop --------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// Fuzzer's main loop.
+//===----------------------------------------------------------------------===//
+
+#include "FuzzerInternal.h"
+#include <sanitizer/coverage_interface.h>
+#include <algorithm>
+
+namespace fuzzer {
+
+// Only one Fuzzer per process.
+static Fuzzer *F;
+
+Fuzzer::Fuzzer(UserSuppliedFuzzer &USF, FuzzingOptions Options)
+    : USF(USF), Options(Options) {
+  SetDeathCallback();
+  InitializeTraceState();
+  assert(!F);
+  F = this;
+}
+
+void Fuzzer::SetDeathCallback() {
+  __sanitizer_set_death_callback(StaticDeathCallback);
+}
+
+void Fuzzer::PrintUnitInASCIIOrTokens(const Unit &U, const char *PrintAfter) {
+  if (Options.Tokens.empty()) {
+    PrintASCII(U, PrintAfter);
+  } else {
+    auto T = SubstituteTokens(U);
+    T.push_back(0);
+    Printf("%s%s", T.data(), PrintAfter);
+  }
+}
+
+void Fuzzer::StaticDeathCallback() {
+  assert(F);
+  F->DeathCallback();
+}
+
+void Fuzzer::DeathCallback() {
+  Printf("DEATH:\n");
+  Print(CurrentUnit, "\n");
+  PrintUnitInASCIIOrTokens(CurrentUnit, "\n");
+  WriteToCrash(CurrentUnit, "crash-");
+}
+
+void Fuzzer::StaticAlarmCallback() {
+  assert(F);
+  F->AlarmCallback();
+}
+
+void Fuzzer::AlarmCallback() {
+  assert(Options.UnitTimeoutSec > 0);
+  size_t Seconds =
+      duration_cast<seconds>(system_clock::now() - UnitStartTime).count();
+  if (Seconds == 0) return;
+  if (Options.Verbosity >= 2)
+    Printf("AlarmCallback %zd\n", Seconds);
+  if (Seconds >= (size_t)Options.UnitTimeoutSec) {
+    Printf("ALARM: working on the last Unit for %zd seconds\n", Seconds);
+    Printf("       and the timeout value is %d (use -timeout=N to change)\n",
+           Options.UnitTimeoutSec);
+    Print(CurrentUnit, "\n");
+    PrintUnitInASCIIOrTokens(CurrentUnit, "\n");
+    WriteToCrash(CurrentUnit, "timeout-");
+    exit(1);
+  }
+}
+
+void Fuzzer::PrintStats(const char *Where, size_t Cov, const char *End) {
+  if (!Options.Verbosity) return;
+  size_t Seconds = secondsSinceProcessStartUp();
+  size_t ExecPerSec = (Seconds ? TotalNumberOfRuns / Seconds : 0);
+  Printf("#%zd\t%s cov %zd bits %zd units %zd exec/s %zd %s", TotalNumberOfRuns,
+         Where, Cov, TotalBits(), Corpus.size(), ExecPerSec, End);
+}
+
+void Fuzzer::RereadOutputCorpus() {
+  if (Options.OutputCorpus.empty()) return;
+  std::vector<Unit> AdditionalCorpus;
+  ReadDirToVectorOfUnits(Options.OutputCorpus.c_str(), &AdditionalCorpus,
+                         &EpochOfLastReadOfOutputCorpus);
+  if (Corpus.empty()) {
+    Corpus = AdditionalCorpus;
+    return;
+  }
+  if (!Options.Reload) return;
+  if (Options.Verbosity >= 2)
+    Printf("Reload: read %zd new units.\n",  AdditionalCorpus.size());
+  for (auto &X : AdditionalCorpus) {
+    if (X.size() > (size_t)Options.MaxLen)
+      X.resize(Options.MaxLen);
+    if (UnitHashesAddedToCorpus.insert(Hash(X)).second) {
+      CurrentUnit.clear();
+      CurrentUnit.insert(CurrentUnit.begin(), X.begin(), X.end());
+      size_t NewCoverage = RunOne(CurrentUnit);
+      if (NewCoverage) {
+        Corpus.push_back(X);
+        if (Options.Verbosity >= 1)
+          PrintStats("RELOAD", NewCoverage);
+      }
+    }
+  }
+}
+
+void Fuzzer::ShuffleAndMinimize() {
+  size_t MaxCov = 0;
+  bool PreferSmall =
+      (Options.PreferSmallDuringInitialShuffle == 1 ||
+       (Options.PreferSmallDuringInitialShuffle == -1 && rand() % 2));
+  if (Options.Verbosity)
+    Printf("PreferSmall: %d\n", PreferSmall);
+  PrintStats("READ  ", 0);
+  std::vector<Unit> NewCorpus;
+  std::random_shuffle(Corpus.begin(), Corpus.end());
+  if (PreferSmall)
+    std::stable_sort(
+        Corpus.begin(), Corpus.end(),
+        [](const Unit &A, const Unit &B) { return A.size() < B.size(); });
+  Unit &U = CurrentUnit;
+  for (const auto &C : Corpus) {
+    for (size_t First = 0; First < 1; First++) {
+      U.clear();
+      size_t Last = std::min(First + Options.MaxLen, C.size());
+      U.insert(U.begin(), C.begin() + First, C.begin() + Last);
+      size_t NewCoverage = RunOne(U);
+      if (NewCoverage) {
+        MaxCov = NewCoverage;
+        NewCorpus.push_back(U);
+        if (Options.Verbosity >= 2)
+          Printf("NEW0: %zd L %zd\n", NewCoverage, U.size());
+      }
+    }
+  }
+  Corpus = NewCorpus;
+  for (auto &X : Corpus)
+    UnitHashesAddedToCorpus.insert(Hash(X));
+  PrintStats("INITED", MaxCov);
+}
+
+size_t Fuzzer::RunOne(const Unit &U) {
+  UnitStartTime = system_clock::now();
+  TotalNumberOfRuns++;
+  size_t Res = 0;
+  if (Options.UseFullCoverageSet)
+    Res = RunOneMaximizeFullCoverageSet(U);
+  else
+    Res = RunOneMaximizeTotalCoverage(U);
+  auto UnitStopTime = system_clock::now();
+  auto TimeOfUnit =
+      duration_cast<seconds>(UnitStopTime - UnitStartTime).count();
+  if (TimeOfUnit > TimeOfLongestUnitInSeconds) {
+    TimeOfLongestUnitInSeconds = TimeOfUnit;
+    Printf("Longest unit: %zd s:\n", TimeOfLongestUnitInSeconds);
+    Print(U, "\n");
+  }
+  return Res;
+}
+
+void Fuzzer::RunOneAndUpdateCorpus(const Unit &U) {
+  if (TotalNumberOfRuns >= Options.MaxNumberOfRuns)
+    return;
+  ReportNewCoverage(RunOne(U), U);
+}
+
+static uintptr_t HashOfArrayOfPCs(uintptr_t *PCs, uintptr_t NumPCs) {
+  uintptr_t Res = 0;
+  for (uintptr_t i = 0; i < NumPCs; i++) {
+    Res = (Res + PCs[i]) * 7;
+  }
+  return Res;
+}
+
+Unit Fuzzer::SubstituteTokens(const Unit &U) const {
+  Unit Res;
+  for (auto Idx : U) {
+    if (Idx < Options.Tokens.size()) {
+      std::string Token = Options.Tokens[Idx];
+      Res.insert(Res.end(), Token.begin(), Token.end());
+    } else {
+      Res.push_back(' ');
+    }
+  }
+  // FIXME: Apply DFSan labels.
+  return Res;
+}
+
+void Fuzzer::ExecuteCallback(const Unit &U) {
+  if (Options.Tokens.empty()) {
+    USF.TargetFunction(U.data(), U.size());
+  } else {
+    auto T = SubstituteTokens(U);
+    USF.TargetFunction(T.data(), T.size());
+  }
+}
+
+// Experimental.
+// Fuly reset the current coverage state, run a single unit,
+// compute a hash function from the full coverage set,
+// return non-zero if the hash value is new.
+// This produces tons of new units and as is it's only suitable for small tests,
+// e.g. test/FullCoverageSetTest.cpp. FIXME: make it scale.
+size_t Fuzzer::RunOneMaximizeFullCoverageSet(const Unit &U) {
+  __sanitizer_reset_coverage();
+  ExecuteCallback(U);
+  uintptr_t *PCs;
+  uintptr_t NumPCs =__sanitizer_get_coverage_guards(&PCs);
+  if (FullCoverageSets.insert(HashOfArrayOfPCs(PCs, NumPCs)).second)
+    return FullCoverageSets.size();
+  return 0;
+}
+
+size_t Fuzzer::RunOneMaximizeTotalCoverage(const Unit &U) {
+  size_t NumCounters = __sanitizer_get_number_of_counters();
+  if (Options.UseCounters) {
+    CounterBitmap.resize(NumCounters);
+    __sanitizer_update_counter_bitset_and_clear_counters(0);
+  }
+  size_t OldCoverage = __sanitizer_get_total_unique_coverage();
+  ExecuteCallback(U);
+  size_t NewCoverage = __sanitizer_get_total_unique_coverage();
+  size_t NumNewBits = 0;
+  if (Options.UseCounters)
+    NumNewBits = __sanitizer_update_counter_bitset_and_clear_counters(
+        CounterBitmap.data());
+
+  if (!(TotalNumberOfRuns & (TotalNumberOfRuns - 1)) && Options.Verbosity)
+    PrintStats("pulse ", NewCoverage);
+
+  if (NewCoverage > OldCoverage || NumNewBits)
+    return NewCoverage;
+  return 0;
+}
+
+void Fuzzer::WriteToOutputCorpus(const Unit &U) {
+  if (Options.OutputCorpus.empty()) return;
+  std::string Path = DirPlusFile(Options.OutputCorpus, Hash(U));
+  WriteToFile(U, Path);
+  if (Options.Verbosity >= 2)
+    Printf("Written to %s\n", Path.c_str());
+}
+
+void Fuzzer::WriteToCrash(const Unit &U, const char *Prefix) {
+  std::string Path = Prefix + Hash(U);
+  WriteToFile(U, Path);
+  Printf("CRASHED; file written to %s\nBase64: ", Path.c_str());
+  PrintFileAsBase64(Path);
+}
+
+void Fuzzer::SaveCorpus() {
+  if (Options.OutputCorpus.empty()) return;
+  for (const auto &U : Corpus)
+    WriteToFile(U, DirPlusFile(Options.OutputCorpus, Hash(U)));
+  if (Options.Verbosity)
+    Printf("Written corpus of %zd files to %s\n", Corpus.size(),
+           Options.OutputCorpus.c_str());
+}
+
+void Fuzzer::ReportNewCoverage(size_t NewCoverage, const Unit &U) {
+  if (!NewCoverage) return;
+  Corpus.push_back(U);
+  UnitHashesAddedToCorpus.insert(Hash(U));
+  PrintStats("NEW   ", NewCoverage, "");
+  if (Options.Verbosity) {
+    Printf(" L: %zd", U.size());
+    if (U.size() < 30) {
+      Printf(" ");
+      PrintUnitInASCIIOrTokens(U, "\t");
+      Print(U);
+    }
+    Printf("\n");
+  }
+  WriteToOutputCorpus(U);
+  if (Options.ExitOnFirst)
+    exit(0);
+}
+
+void Fuzzer::MutateAndTestOne(Unit *U) {
+  for (int i = 0; i < Options.MutateDepth; i++) {
+    StartTraceRecording();
+    size_t Size = U->size();
+    U->resize(Options.MaxLen);
+    size_t NewSize = USF.Mutate(U->data(), Size, U->size());
+    assert(NewSize > 0 && NewSize <= (size_t)Options.MaxLen);
+    U->resize(NewSize);
+    RunOneAndUpdateCorpus(*U);
+    size_t NumTraceBasedMutations = StopTraceRecording();
+    for (size_t j = 0; j < NumTraceBasedMutations; j++) {
+      ApplyTraceBasedMutation(j, U);
+      RunOneAndUpdateCorpus(*U);
+    }
+  }
+}
+
+void Fuzzer::Loop(size_t NumIterations) {
+  for (size_t i = 1; i <= NumIterations; i++) {
+    for (size_t J1 = 0; J1 < Corpus.size(); J1++) {
+      SyncCorpus();
+      RereadOutputCorpus();
+      if (TotalNumberOfRuns >= Options.MaxNumberOfRuns)
+        return;
+      // First, simply mutate the unit w/o doing crosses.
+      CurrentUnit = Corpus[J1];
+      MutateAndTestOne(&CurrentUnit);
+      // Now, cross with others.
+      if (Options.DoCrossOver && !Corpus[J1].empty()) {
+        for (size_t J2 = 0; J2 < Corpus.size(); J2++) {
+          CurrentUnit.resize(Options.MaxLen);
+          size_t NewSize = USF.CrossOver(
+              Corpus[J1].data(), Corpus[J1].size(), Corpus[J2].data(),
+              Corpus[J2].size(), CurrentUnit.data(), CurrentUnit.size());
+          assert(NewSize > 0 && NewSize <= (size_t)Options.MaxLen);
+          CurrentUnit.resize(NewSize);
+          MutateAndTestOne(&CurrentUnit);
+        }
+      }
+    }
+  }
+}
+
+void Fuzzer::SyncCorpus() {
+  if (Options.SyncCommand.empty() || Options.OutputCorpus.empty()) return;
+  auto Now = system_clock::now();
+  if (duration_cast<seconds>(Now - LastExternalSync).count() <
+      Options.SyncTimeout)
+    return;
+  LastExternalSync = Now;
+  ExecuteCommand(Options.SyncCommand + " " + Options.OutputCorpus);
+}
+
+}  // namespace fuzzer