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//===- FuzzerInternal.h - Internal header for the Fuzzer --------*- C++ -* ===//
// The LLVM Compiler Infrastructure
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
// Define the main class fuzzer::Fuzzer and most functions.
#include <cassert>
#include <climits>
#include <chrono>
#include <cstddef>
#include <cstdlib>
#include <string>
#include <vector>
#include <unordered_set>
#include "FuzzerInterface.h"
namespace fuzzer {
using namespace std::chrono;
std::string FileToString(const std::string &Path);
Unit FileToVector(const std::string &Path);
void ReadDirToVectorOfUnits(const char *Path, std::vector<Unit> *V,
long *Epoch);
void WriteToFile(const Unit &U, const std::string &Path);
void CopyFileToErr(const std::string &Path);
// Returns "Dir/FileName" or equivalent for the current OS.
std::string DirPlusFile(const std::string &DirPath,
const std::string &FileName);
void Printf(const char *Fmt, ...);
void Print(const Unit &U, const char *PrintAfter = "");
void PrintASCII(const uint8_t *Data, size_t Size, const char *PrintAfter = "");
void PrintASCII(const Unit &U, const char *PrintAfter = "");
std::string Hash(const Unit &U);
void SetTimer(int Seconds);
std::string Base64(const Unit &U);
int ExecuteCommand(const std::string &Command);
// Private copy of SHA1 implementation.
static const int kSHA1NumBytes = 20;
// Computes SHA1 hash of 'Len' bytes in 'Data', writes kSHA1NumBytes to 'Out'.
void ComputeSHA1(const uint8_t *Data, size_t Len, uint8_t *Out);
// Changes U to contain only ASCII (isprint+isspace) characters.
// Returns true iff U has been changed.
bool ToASCII(Unit &U);
bool IsASCII(const Unit &U);
int NumberOfCpuCores();
int GetPid();
// Dictionary.
// Parses one dictionary entry.
// If successfull, write the enty to Unit and returns true,
// otherwise returns false.
bool ParseOneDictionaryEntry(const std::string &Str, Unit *U);
// Parses the dictionary file, fills Units, returns true iff all lines
// were parsed succesfully.
bool ParseDictionaryFile(const std::string &Text, std::vector<Unit> *Units);
class Fuzzer {
struct FuzzingOptions {
int Verbosity = 1;
int MaxLen = 0;
int UnitTimeoutSec = 300;
int MaxTotalTimeSec = 0;
bool DoCrossOver = true;
int MutateDepth = 5;
bool ExitOnFirst = false;
bool UseCounters = false;
bool UseIndirCalls = true;
bool UseTraces = false;
bool UseFullCoverageSet = false;
bool Reload = true;
bool ShuffleAtStartUp = true;
int PreferSmallDuringInitialShuffle = -1;
size_t MaxNumberOfRuns = ULONG_MAX;
int SyncTimeout = 600;
int ReportSlowUnits = 10;
bool OnlyASCII = false;
std::string OutputCorpus;
std::string SyncCommand;
std::string ArtifactPrefix = "./";
std::string ExactArtifactPath;
bool SaveArtifacts = true;
bool PrintNEW = true; // Print a status line when new units are found;
bool OutputCSV = false;
bool PrintNewCovPcs = false;
Fuzzer(UserSuppliedFuzzer &USF, FuzzingOptions Options);
void AddToCorpus(const Unit &U) { Corpus.push_back(U); }
size_t ChooseUnitIdxToMutate();
const Unit &ChooseUnitToMutate() { return Corpus[ChooseUnitIdxToMutate()]; };
void Loop();
void Drill();
void ShuffleAndMinimize();
void InitializeTraceState();
size_t CorpusSize() const { return Corpus.size(); }
void ReadDir(const std::string &Path, long *Epoch) {
Printf("Loading corpus: %s\n", Path.c_str());
ReadDirToVectorOfUnits(Path.c_str(), &Corpus, Epoch);
void RereadOutputCorpus();
// Save the current corpus to OutputCorpus.
void SaveCorpus();
size_t secondsSinceProcessStartUp() {
return duration_cast<seconds>(system_clock::now() - ProcessStartTime)
size_t getTotalNumberOfRuns() { return TotalNumberOfRuns; }
static void StaticAlarmCallback();
void ExecuteCallback(const Unit &U);
// Merge Corpora[1:] into Corpora[0].
void Merge(const std::vector<std::string> &Corpora);
void AlarmCallback();
void MutateAndTestOne();
void ReportNewCoverage(const Unit &U);
bool RunOne(const Unit &U);
void RunOneAndUpdateCorpus(Unit &U);
void WriteToOutputCorpus(const Unit &U);
void WriteUnitToFileWithPrefix(const Unit &U, const char *Prefix);
void PrintStats(const char *Where, const char *End = "\n");
void PrintStatusForNewUnit(const Unit &U);
void PrintUnitInASCII(const Unit &U, const char *PrintAfter = "");
void SyncCorpus();
size_t RecordBlockCoverage();
size_t RecordCallerCalleeCoverage();
void PrepareCoverageBeforeRun();
bool CheckCoverageAfterRun();
// Trace-based fuzzing: we run a unit with some kind of tracing
// enabled and record potentially useful mutations. Then
// We apply these mutations one by one to the unit and run it again.
// Start tracing; forget all previously proposed mutations.
void StartTraceRecording();
// Stop tracing.
void StopTraceRecording();
void SetDeathCallback();
static void StaticDeathCallback();
void DeathCallback();
Unit CurrentUnit;
size_t TotalNumberOfRuns = 0;
size_t TotalNumberOfExecutedTraceBasedMutations = 0;
std::vector<Unit> Corpus;
std::unordered_set<std::string> UnitHashesAddedToCorpus;
// For UseCounters
std::vector<uint8_t> CounterBitmap;
size_t TotalBits() { // Slow. Call it only for printing stats.
size_t Res = 0;
for (auto x : CounterBitmap) Res += __builtin_popcount(x);
return Res;
UserSuppliedFuzzer &USF;
FuzzingOptions Options;
system_clock::time_point ProcessStartTime = system_clock::now();
system_clock::time_point LastExternalSync = system_clock::now();
system_clock::time_point UnitStartTime;
long TimeOfLongestUnitInSeconds = 0;
long EpochOfLastReadOfOutputCorpus = 0;
size_t LastRecordedBlockCoverage = 0;
size_t LastRecordedCallerCalleeCoverage = 0;
size_t LastCoveragePcBufferLen = 0;
class SimpleUserSuppliedFuzzer: public UserSuppliedFuzzer {
SimpleUserSuppliedFuzzer(FuzzerRandomBase *Rand, UserCallback Callback)
: UserSuppliedFuzzer(Rand), Callback(Callback) {}
virtual int TargetFunction(const uint8_t *Data, size_t Size) override {
return Callback(Data, Size);
UserCallback Callback = nullptr;
}; // namespace fuzzer