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llvm-project/llvm/lib/Fuzzer/FuzzerLoop.cpp

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//===- 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 <algorithm>
#include <cstring>
#include <memory>
#if defined(__has_include)
#if __has_include(<sanitizer / coverage_interface.h>)
#include <sanitizer/coverage_interface.h>
#endif
#if __has_include(<sanitizer / lsan_interface.h>)
#include <sanitizer/lsan_interface.h>
#endif
#endif
#define NO_SANITIZE_MEMORY
#if defined(__has_feature)
#if __has_feature(memory_sanitizer)
#undef NO_SANITIZE_MEMORY
#define NO_SANITIZE_MEMORY __attribute__((no_sanitize_memory))
#endif
#endif
extern "C" {
// Re-declare some of the sanitizer functions as "weak" so that
// libFuzzer can be linked w/o the sanitizers and sanitizer-coverage
// (in which case it will complain at start-up time).
__attribute__((weak)) void __sanitizer_print_stack_trace();
__attribute__((weak)) void __sanitizer_reset_coverage();
__attribute__((weak)) size_t __sanitizer_get_total_unique_caller_callee_pairs();
__attribute__((weak)) size_t __sanitizer_get_total_unique_coverage();
__attribute__((weak)) void
__sanitizer_set_death_callback(void (*callback)(void));
__attribute__((weak)) size_t __sanitizer_get_number_of_counters();
__attribute__((weak)) uintptr_t
__sanitizer_update_counter_bitset_and_clear_counters(uint8_t *bitset);
__attribute__((weak)) uintptr_t
__sanitizer_get_coverage_pc_buffer(uintptr_t **data);
__attribute__((weak)) size_t LLVMFuzzerCustomMutator(uint8_t *Data, size_t Size,
size_t MaxSize,
unsigned int Seed);
__attribute__((weak)) void __sanitizer_malloc_hook(void *ptr, size_t size);
__attribute__((weak)) void __sanitizer_free_hook(void *ptr);
__attribute__((weak)) void __lsan_enable();
__attribute__((weak)) void __lsan_disable();
__attribute__((weak)) int __lsan_do_recoverable_leak_check();
}
namespace fuzzer {
static const size_t kMaxUnitSizeToPrint = 256;
static void MissingWeakApiFunction(const char *FnName) {
Printf("ERROR: %s is not defined. Exiting.\n"
"Did you use -fsanitize-coverage=... to build your code?\n",
FnName);
exit(1);
}
#define CHECK_WEAK_API_FUNCTION(fn) \
do { \
if (!fn) \
MissingWeakApiFunction(#fn); \
} while (false)
// Only one Fuzzer per process.
static Fuzzer *F;
size_t Mutate(uint8_t *Data, size_t Size, size_t MaxSize) {
assert(F);
return F->GetMD().Mutate(Data, Size, MaxSize);
}
Fuzzer::Fuzzer(UserCallback CB, MutationDispatcher &MD, FuzzingOptions Options)
: CB(CB), MD(MD), Options(Options) {
SetDeathCallback();
InitializeTraceState();
assert(!F);
F = this;
}
void Fuzzer::SetDeathCallback() {
CHECK_WEAK_API_FUNCTION(__sanitizer_set_death_callback);
__sanitizer_set_death_callback(StaticDeathCallback);
}
void Fuzzer::StaticDeathCallback() {
assert(F);
F->DeathCallback();
}
void Fuzzer::DumpCurrentUnit(const char *Prefix) {
if (CurrentUnitSize <= kMaxUnitSizeToPrint) {
PrintHexArray(CurrentUnitData, CurrentUnitSize, "\n");
PrintASCII(CurrentUnitData, CurrentUnitSize, "\n");
}
WriteUnitToFileWithPrefix(
{CurrentUnitData, CurrentUnitData + CurrentUnitSize}, Prefix);
}
NO_SANITIZE_MEMORY
void Fuzzer::DeathCallback() {
if (!CurrentUnitSize) return;
Printf("DEATH:\n");
DumpCurrentUnit("crash-");
PrintFinalStats();
}
void Fuzzer::StaticAlarmCallback() {
assert(F);
F->AlarmCallback();
}
void Fuzzer::StaticCrashSignalCallback() {
assert(F);
F->CrashCallback();
}
void Fuzzer::StaticInterruptCallback() {
assert(F);
F->InterruptCallback();
}
void Fuzzer::CrashCallback() {
Printf("==%d== ERROR: libFuzzer: deadly signal\n", GetPid());
if (__sanitizer_print_stack_trace)
__sanitizer_print_stack_trace();
Printf("NOTE: libFuzzer has rudimentary signal handlers.\n"
" Combine libFuzzer with AddressSanitizer or similar for better "
"crash reports.\n");
Printf("SUMMARY: libFuzzer: deadly signal\n");
DumpCurrentUnit("crash-");
PrintFinalStats();
exit(Options.ErrorExitCode);
}
void Fuzzer::InterruptCallback() {
Printf("==%d== libFuzzer: run interrupted; exiting\n", GetPid());
PrintFinalStats();
_Exit(0); // Stop right now, don't perform any at-exit actions.
}
NO_SANITIZE_MEMORY
void Fuzzer::AlarmCallback() {
assert(Options.UnitTimeoutSec > 0);
if (InOOMState) {
Printf("==%d== ERROR: libFuzzer: out-of-memory (used: %zdMb; limit: %zdMb)\n",
GetPid(), GetPeakRSSMb(), Options.RssLimitMb);
Printf(" To change the out-of-memory limit use -rss_limit_mb=<N>\n");
if (CurrentUnitSize && CurrentUnitData) {
DumpCurrentUnit("oom-");
if (__sanitizer_print_stack_trace)
__sanitizer_print_stack_trace();
}
Printf("SUMMARY: libFuzzer: out-of-memory\n");
PrintFinalStats();
_Exit(Options.ErrorExitCode); // Stop right now.
}
if (!CurrentUnitSize)
return; // We have not started running units yet.
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);
DumpCurrentUnit("timeout-");
Printf("==%d== ERROR: libFuzzer: timeout after %d seconds\n", GetPid(),
Seconds);
if (__sanitizer_print_stack_trace)
__sanitizer_print_stack_trace();
Printf("SUMMARY: libFuzzer: timeout\n");
PrintFinalStats();
_Exit(Options.TimeoutExitCode); // Stop right now.
}
}
void Fuzzer::RssLimitCallback() {
InOOMState = true;
SignalToMainThread();
SleepSeconds(5);
Printf("Signal to main thread failed (non-linux?). Exiting.\n");
_Exit(Options.ErrorExitCode);
return;
}
void Fuzzer::PrintStats(const char *Where, const char *End) {
size_t ExecPerSec = execPerSec();
if (Options.OutputCSV) {
static bool csvHeaderPrinted = false;
if (!csvHeaderPrinted) {
csvHeaderPrinted = true;
Printf("runs,block_cov,bits,cc_cov,corpus,execs_per_sec,tbms,reason\n");
}
Printf("%zd,%zd,%zd,%zd,%zd,%zd,%s\n", TotalNumberOfRuns,
LastRecordedBlockCoverage, TotalBits(),
LastRecordedCallerCalleeCoverage, Corpus.size(), ExecPerSec,
Where);
}
if (!Options.Verbosity)
return;
Printf("#%zd\t%s", TotalNumberOfRuns, Where);
if (LastRecordedBlockCoverage)
Printf(" cov: %zd", LastRecordedBlockCoverage);
if (LastRecordedPcMapSize)
Printf(" path: %zd", LastRecordedPcMapSize);
if (auto TB = TotalBits())
Printf(" bits: %zd", TB);
if (LastRecordedCallerCalleeCoverage)
Printf(" indir: %zd", LastRecordedCallerCalleeCoverage);
Printf(" units: %zd exec/s: %zd", Corpus.size(), ExecPerSec);
Printf("%s", End);
}
void Fuzzer::PrintFinalStats() {
if (!Options.PrintFinalStats) return;
size_t ExecPerSec = execPerSec();
Printf("stat::number_of_executed_units: %zd\n", TotalNumberOfRuns);
Printf("stat::average_exec_per_sec: %zd\n", ExecPerSec);
Printf("stat::new_units_added: %zd\n", NumberOfNewUnitsAdded);
Printf("stat::slowest_unit_time_sec: %zd\n", TimeOfLongestUnitInSeconds);
Printf("stat::peak_rss_mb: %zd\n", GetPeakRSSMb());
}
size_t Fuzzer::MaxUnitSizeInCorpus() const {
size_t Res = 0;
for (auto &X : Corpus)
Res = std::max(Res, X.size());
return Res;
}
void Fuzzer::SetMaxLen(size_t MaxLen) {
assert(Options.MaxLen == 0); // Can only reset MaxLen from 0 to non-0.
assert(MaxLen);
Options.MaxLen = MaxLen;
Printf("INFO: -max_len is not provided, using %zd\n", Options.MaxLen);
}
void Fuzzer::RereadOutputCorpus(size_t MaxSize) {
if (Options.OutputCorpus.empty())
return;
std::vector<Unit> AdditionalCorpus;
ReadDirToVectorOfUnits(Options.OutputCorpus.c_str(), &AdditionalCorpus,
&EpochOfLastReadOfOutputCorpus, MaxSize);
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() > MaxSize)
X.resize(MaxSize);
if (UnitHashesAddedToCorpus.insert(Hash(X)).second) {
if (RunOne(X)) {
Corpus.push_back(X);
UpdateCorpusDistribution();
PrintStats("RELOAD");
}
}
}
}
void Fuzzer::ShuffleCorpus(UnitVector *V) {
std::random_shuffle(V->begin(), V->end(), MD.GetRand());
if (Options.PreferSmall)
std::stable_sort(V->begin(), V->end(), [](const Unit &A, const Unit &B) {
return A.size() < B.size();
});
}
void Fuzzer::ShuffleAndMinimize() {
PrintStats("READ ");
std::vector<Unit> NewCorpus;
if (Options.ShuffleAtStartUp)
ShuffleCorpus(&Corpus);
for (const auto &U : Corpus) {
if (RunOne(U)) {
NewCorpus.push_back(U);
if (Options.Verbosity >= 2)
Printf("NEW0: %zd L %zd\n", LastRecordedBlockCoverage, U.size());
}
}
Corpus = NewCorpus;
UpdateCorpusDistribution();
for (auto &X : Corpus)
UnitHashesAddedToCorpus.insert(Hash(X));
PrintStats("INITED");
CheckForMemoryLeaks();
}
bool Fuzzer::RunOne(const uint8_t *Data, size_t Size) {
TotalNumberOfRuns++;
PrepareCoverageBeforeRun();
ExecuteCallback(Data, Size);
bool Res = CheckCoverageAfterRun();
auto UnitStopTime = system_clock::now();
auto TimeOfUnit =
duration_cast<seconds>(UnitStopTime - UnitStartTime).count();
if (!(TotalNumberOfRuns & (TotalNumberOfRuns - 1)) &&
secondsSinceProcessStartUp() >= 2)
PrintStats("pulse ");
if (TimeOfUnit > TimeOfLongestUnitInSeconds &&
TimeOfUnit >= Options.ReportSlowUnits) {
TimeOfLongestUnitInSeconds = TimeOfUnit;
Printf("Slowest unit: %zd s:\n", TimeOfLongestUnitInSeconds);
WriteUnitToFileWithPrefix({Data, Data + Size}, "slow-unit-");
}
return Res;
}
void Fuzzer::RunOneAndUpdateCorpus(uint8_t *Data, size_t Size) {
if (TotalNumberOfRuns >= Options.MaxNumberOfRuns)
return;
if (Options.OnlyASCII)
ToASCII(Data, Size);
if (RunOne(Data, Size))
ReportNewCoverage({Data, Data + Size});
}
// Leak detection is expensive, so we first check if there were more mallocs
// than frees (using the sanitizer malloc hooks) and only then try to call lsan.
struct MallocFreeTracer {
void Start() {
Mallocs = 0;
Frees = 0;
}
// Returns true if there were more mallocs than frees.
bool Stop() { return Mallocs > Frees; }
size_t Mallocs;
size_t Frees;
};
static thread_local MallocFreeTracer AllocTracer;
extern "C" {
void __sanitizer_malloc_hook(void *ptr, size_t size) { AllocTracer.Mallocs++; }
void __sanitizer_free_hook(void *ptr) { AllocTracer.Frees++; }
} // extern "C"
void Fuzzer::ExecuteCallback(const uint8_t *Data, size_t Size) {
UnitStartTime = system_clock::now();
// We copy the contents of Unit into a separate heap buffer
// so that we reliably find buffer overflows in it.
std::unique_ptr<uint8_t[]> DataCopy(new uint8_t[Size]);
memcpy(DataCopy.get(), Data, Size);
AssignTaintLabels(DataCopy.get(), Size);
CurrentUnitData = DataCopy.get();
CurrentUnitSize = Size;
AllocTracer.Start();
int Res = CB(DataCopy.get(), Size);
(void)Res;
HasMoreMallocsThanFrees = AllocTracer.Stop();
CurrentUnitSize = 0;
CurrentUnitData = nullptr;
assert(Res == 0);
}
size_t Fuzzer::RecordBlockCoverage() {
CHECK_WEAK_API_FUNCTION(__sanitizer_get_total_unique_coverage);
uintptr_t PrevCoverage = LastRecordedBlockCoverage;
LastRecordedBlockCoverage = __sanitizer_get_total_unique_coverage();
if (PrevCoverage == LastRecordedBlockCoverage || !Options.PrintNewCovPcs)
return LastRecordedBlockCoverage;
uintptr_t PrevBufferLen = LastCoveragePcBufferLen;
uintptr_t *CoverageBuf;
LastCoveragePcBufferLen = __sanitizer_get_coverage_pc_buffer(&CoverageBuf);
assert(CoverageBuf);
for (size_t i = PrevBufferLen; i < LastCoveragePcBufferLen; ++i) {
Printf("%p\n", CoverageBuf[i]);
}
return LastRecordedBlockCoverage;
}
size_t Fuzzer::RecordCallerCalleeCoverage() {
if (!Options.UseIndirCalls)
return 0;
if (!__sanitizer_get_total_unique_caller_callee_pairs)
return 0;
return LastRecordedCallerCalleeCoverage =
__sanitizer_get_total_unique_caller_callee_pairs();
}
void Fuzzer::PrepareCoverageBeforeRun() {
if (Options.UseCounters) {
size_t NumCounters = __sanitizer_get_number_of_counters();
CounterBitmap.resize(NumCounters);
__sanitizer_update_counter_bitset_and_clear_counters(0);
}
RecordBlockCoverage();
RecordCallerCalleeCoverage();
}
bool Fuzzer::CheckCoverageAfterRun() {
size_t OldCoverage = LastRecordedBlockCoverage;
size_t NewCoverage = RecordBlockCoverage();
size_t OldCallerCalleeCoverage = LastRecordedCallerCalleeCoverage;
size_t NewCallerCalleeCoverage = RecordCallerCalleeCoverage();
size_t NumNewBits = 0;
size_t OldPcMapSize = LastRecordedPcMapSize;
PcMapMergeCurrentToCombined();
size_t NewPcMapSize = PcMapCombinedSize();
LastRecordedPcMapSize = NewPcMapSize;
if (NewPcMapSize > OldPcMapSize)
return true;
if (Options.UseCounters)
NumNewBits = __sanitizer_update_counter_bitset_and_clear_counters(
CounterBitmap.data());
return NewCoverage > OldCoverage ||
NewCallerCalleeCoverage > OldCallerCalleeCoverage || NumNewBits;
}
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());
assert(!Options.OnlyASCII || IsASCII(U));
}
void Fuzzer::WriteUnitToFileWithPrefix(const Unit &U, const char *Prefix) {
if (!Options.SaveArtifacts)
return;
std::string Path = Options.ArtifactPrefix + Prefix + Hash(U);
if (!Options.ExactArtifactPath.empty())
Path = Options.ExactArtifactPath; // Overrides ArtifactPrefix.
WriteToFile(U, Path);
Printf("artifact_prefix='%s'; Test unit written to %s\n",
Options.ArtifactPrefix.c_str(), Path.c_str());
if (U.size() <= kMaxUnitSizeToPrint)
Printf("Base64: %s\n", Base64(U).c_str());
}
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::PrintStatusForNewUnit(const Unit &U) {
if (!Options.PrintNEW)
return;
PrintStats("NEW ", "");
if (Options.Verbosity) {
Printf(" L: %zd ", U.size());
MD.PrintMutationSequence();
Printf("\n");
}
}
void Fuzzer::ReportNewCoverage(const Unit &U) {
Corpus.push_back(U);
UpdateCorpusDistribution();
UnitHashesAddedToCorpus.insert(Hash(U));
MD.RecordSuccessfulMutationSequence();
PrintStatusForNewUnit(U);
WriteToOutputCorpus(U);
NumberOfNewUnitsAdded++;
}
// Finds minimal number of units in 'Extra' that add coverage to 'Initial'.
// We do it by actually executing the units, sometimes more than once,
// because we may be using different coverage-like signals and the only
// common thing between them is that we can say "this unit found new stuff".
UnitVector Fuzzer::FindExtraUnits(const UnitVector &Initial,
const UnitVector &Extra) {
UnitVector Res = Extra;
size_t OldSize = Res.size();
for (int Iter = 0; Iter < 10; Iter++) {
ShuffleCorpus(&Res);
ResetCoverage();
for (auto &U : Initial)
RunOne(U);
Corpus.clear();
for (auto &U : Res)
if (RunOne(U))
Corpus.push_back(U);
char Stat[7] = "MIN ";
Stat[3] = '0' + Iter;
PrintStats(Stat);
size_t NewSize = Corpus.size();
Res.swap(Corpus);
if (NewSize == OldSize)
break;
OldSize = NewSize;
}
return Res;
}
void Fuzzer::Merge(const std::vector<std::string> &Corpora) {
if (Corpora.size() <= 1) {
Printf("Merge requires two or more corpus dirs\n");
return;
}
std::vector<std::string> ExtraCorpora(Corpora.begin() + 1, Corpora.end());
assert(Options.MaxLen > 0);
UnitVector Initial, Extra;
ReadDirToVectorOfUnits(Corpora[0].c_str(), &Initial, nullptr, Options.MaxLen);
for (auto &C : ExtraCorpora)
ReadDirToVectorOfUnits(C.c_str(), &Extra, nullptr, Options.MaxLen);
if (!Initial.empty()) {
Printf("=== Minimizing the initial corpus of %zd units\n", Initial.size());
Initial = FindExtraUnits({}, Initial);
}
Printf("=== Merging extra %zd units\n", Extra.size());
auto Res = FindExtraUnits(Initial, Extra);
for (auto &U: Res)
WriteToOutputCorpus(U);
Printf("=== Merge: written %zd units\n", Res.size());
}
// Tries to call lsan, and if there are leaks exits. We call this right after
// the initial corpus was read because if there are leaky inputs in the corpus
// further fuzzing will likely hit OOMs.
void Fuzzer::CheckForMemoryLeaks() {
if (!Options.DetectLeaks) return;
if (!__lsan_do_recoverable_leak_check)
return;
if (__lsan_do_recoverable_leak_check()) {
Printf("==%d== ERROR: libFuzzer: initial corpus triggers memory leaks.\n"
"Exiting now. Use -detect_leaks=0 to disable leak detection here.\n"
"LeakSanitizer will still check for leaks at the process exit.\n",
GetPid());
PrintFinalStats();
_Exit(Options.ErrorExitCode);
}
}
// Tries detecting a memory leak on the particular input that we have just
// executed before calling this function.
void Fuzzer::TryDetectingAMemoryLeak(uint8_t *Data, size_t Size) {
if (!HasMoreMallocsThanFrees) return; // mallocs==frees, a leak is unlikely.
if (!Options.DetectLeaks) return;
if (!&__lsan_enable || !&__lsan_disable || !__lsan_do_recoverable_leak_check)
return; // No lsan.
// Run the target once again, but with lsan disabled so that if there is
// a real leak we do not report it twice.
__lsan_disable();
RunOneAndUpdateCorpus(Data, Size);
__lsan_enable();
if (!HasMoreMallocsThanFrees) return; // a leak is unlikely.
if (NumberOfLeakDetectionAttempts++ > 1000) {
Options.DetectLeaks = false;
Printf("INFO: libFuzzer disabled leak detection after every mutation.\n"
" Most likely the target function accumulates allocated\n"
" memory in a global state w/o actually leaking it.\n"
" If LeakSanitizer is enabled in this process it will still\n"
" run on the process shutdown.\n");
return;
}
// Now perform the actual lsan pass. This is expensive and we must ensure
// we don't call it too often.
if (__lsan_do_recoverable_leak_check()) { // Leak is found, report it.
CurrentUnitData = Data;
CurrentUnitSize = Size;
DumpCurrentUnit("leak-");
PrintFinalStats();
_Exit(Options.ErrorExitCode); // not exit() to disable lsan further on.
}
}
void Fuzzer::MutateAndTestOne() {
MD.StartMutationSequence();
auto &U = ChooseUnitToMutate();
MutateInPlaceHere.resize(Options.MaxLen);
size_t Size = U.size();
assert(Size <= Options.MaxLen && "Oversized Unit");
memcpy(MutateInPlaceHere.data(), U.data(), Size);
for (int i = 0; i < Options.MutateDepth; i++) {
size_t NewSize = 0;
if (LLVMFuzzerCustomMutator)
NewSize = LLVMFuzzerCustomMutator(MutateInPlaceHere.data(), Size,
Options.MaxLen, MD.GetRand().Rand());
else
NewSize = MD.Mutate(MutateInPlaceHere.data(), Size, Options.MaxLen);
assert(NewSize > 0 && "Mutator returned empty unit");
assert(NewSize <= Options.MaxLen &&
"Mutator return overisized unit");
Size = NewSize;
if (i == 0)
StartTraceRecording();
RunOneAndUpdateCorpus(MutateInPlaceHere.data(), Size);
StopTraceRecording();
TryDetectingAMemoryLeak(MutateInPlaceHere.data(), Size);
}
}
// Returns an index of random unit from the corpus to mutate.
// Hypothesis: units added to the corpus last are more likely to be interesting.
// This function gives more weight to the more recent units.
size_t Fuzzer::ChooseUnitIdxToMutate() {
size_t Idx =
static_cast<size_t>(CorpusDistribution(MD.GetRand().Get_mt19937()));
assert(Idx < Corpus.size());
return Idx;
}
void Fuzzer::ResetCoverage() {
CHECK_WEAK_API_FUNCTION(__sanitizer_reset_coverage);
__sanitizer_reset_coverage();
CounterBitmap.clear();
}
// Experimental search heuristic: drilling.
// - Read, shuffle, execute and minimize the corpus.
// - Choose one random unit.
// - Reset the coverage.
// - Start fuzzing as if the chosen unit was the only element of the corpus.
// - When done, reset the coverage again.
// - Merge the newly created corpus into the original one.
void Fuzzer::Drill() {
// The corpus is already read, shuffled, and minimized.
assert(!Corpus.empty());
Options.PrintNEW = false; // Don't print NEW status lines when drilling.
Unit U = ChooseUnitToMutate();
ResetCoverage();
std::vector<Unit> SavedCorpus;
SavedCorpus.swap(Corpus);
Corpus.push_back(U);
UpdateCorpusDistribution();
assert(Corpus.size() == 1);
RunOne(U);
PrintStats("DRILL ");
std::string SavedOutputCorpusPath; // Don't write new units while drilling.
SavedOutputCorpusPath.swap(Options.OutputCorpus);
Loop();
ResetCoverage();
PrintStats("REINIT");
SavedOutputCorpusPath.swap(Options.OutputCorpus);
for (auto &U : SavedCorpus)
RunOne(U);
PrintStats("MERGE ");
Options.PrintNEW = true;
size_t NumMerged = 0;
for (auto &U : Corpus) {
if (RunOne(U)) {
PrintStatusForNewUnit(U);
NumMerged++;
WriteToOutputCorpus(U);
}
}
PrintStats("MERGED");
if (NumMerged && Options.Verbosity)
Printf("Drilling discovered %zd new units\n", NumMerged);
}
void Fuzzer::Loop() {
system_clock::time_point LastCorpusReload = system_clock::now();
if (Options.DoCrossOver)
MD.SetCorpus(&Corpus);
while (true) {
auto Now = system_clock::now();
if (duration_cast<seconds>(Now - LastCorpusReload).count()) {
RereadOutputCorpus(Options.MaxLen);
LastCorpusReload = Now;
}
if (TotalNumberOfRuns >= Options.MaxNumberOfRuns)
break;
if (Options.MaxTotalTimeSec > 0 &&
secondsSinceProcessStartUp() >
static_cast<size_t>(Options.MaxTotalTimeSec))
break;
// Perform several mutations and runs.
MutateAndTestOne();
}
PrintStats("DONE ", "\n");
MD.PrintRecommendedDictionary();
}
void Fuzzer::UpdateCorpusDistribution() {
size_t N = Corpus.size();
std::vector<double> Intervals(N + 1);
std::vector<double> Weights(N);
std::iota(Intervals.begin(), Intervals.end(), 0);
std::iota(Weights.begin(), Weights.end(), 1);
CorpusDistribution = std::piecewise_constant_distribution<double>(
Intervals.begin(), Intervals.end(), Weights.begin());
}
} // namespace fuzzer
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