1 //===- FuzzerLoop.cpp - Fuzzer's main loop --------------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 //===----------------------------------------------------------------------===//
12 #include "FuzzerInternal.h"
13 #include <sanitizer/coverage_interface.h>
17 __attribute__((weak)) void __sanitizer_print_stack_trace();
21 static const size_t kMaxUnitSizeToPrint = 256;
23 // Only one Fuzzer per process.
26 Fuzzer::Fuzzer(UserSuppliedFuzzer &USF, FuzzingOptions Options)
27 : USF(USF), Options(Options) {
29 InitializeTraceState();
34 void Fuzzer::SetDeathCallback() {
35 __sanitizer_set_death_callback(StaticDeathCallback);
38 void Fuzzer::PrintUnitInASCII(const Unit &U, const char *PrintAfter) {
39 PrintASCII(U, PrintAfter);
42 void Fuzzer::StaticDeathCallback() {
47 void Fuzzer::DeathCallback() {
49 if (CurrentUnit.size() <= kMaxUnitSizeToPrint) {
50 Print(CurrentUnit, "\n");
51 PrintUnitInASCII(CurrentUnit, "\n");
53 WriteUnitToFileWithPrefix(CurrentUnit, "crash-");
56 void Fuzzer::StaticAlarmCallback() {
61 void Fuzzer::AlarmCallback() {
62 assert(Options.UnitTimeoutSec > 0);
64 duration_cast<seconds>(system_clock::now() - UnitStartTime).count();
65 if (Seconds == 0) return;
66 if (Options.Verbosity >= 2)
67 Printf("AlarmCallback %zd\n", Seconds);
68 if (Seconds >= (size_t)Options.UnitTimeoutSec) {
69 Printf("ALARM: working on the last Unit for %zd seconds\n", Seconds);
70 Printf(" and the timeout value is %d (use -timeout=N to change)\n",
71 Options.UnitTimeoutSec);
72 if (CurrentUnit.size() <= kMaxUnitSizeToPrint) {
73 Print(CurrentUnit, "\n");
74 PrintUnitInASCII(CurrentUnit, "\n");
76 WriteUnitToFileWithPrefix(CurrentUnit, "timeout-");
77 Printf("==%d== ERROR: libFuzzer: timeout after %d seconds\n", GetPid(),
79 if (__sanitizer_print_stack_trace)
80 __sanitizer_print_stack_trace();
81 Printf("SUMMARY: libFuzzer: timeout\n");
86 void Fuzzer::PrintStats(const char *Where, size_t Cov, const char *End) {
87 if (!Options.Verbosity) return;
88 size_t Seconds = secondsSinceProcessStartUp();
89 size_t ExecPerSec = (Seconds ? TotalNumberOfRuns / Seconds : 0);
90 Printf("#%zd\t%s cov: %zd bits: %zd units: %zd exec/s: %zd",
91 TotalNumberOfRuns, Where, Cov, TotalBits(), Corpus.size(), ExecPerSec);
92 if (TotalNumberOfExecutedTraceBasedMutations)
93 Printf(" tbm: %zd", TotalNumberOfExecutedTraceBasedMutations);
97 void Fuzzer::RereadOutputCorpus() {
98 if (Options.OutputCorpus.empty()) return;
99 std::vector<Unit> AdditionalCorpus;
100 ReadDirToVectorOfUnits(Options.OutputCorpus.c_str(), &AdditionalCorpus,
101 &EpochOfLastReadOfOutputCorpus);
102 if (Corpus.empty()) {
103 Corpus = AdditionalCorpus;
106 if (!Options.Reload) return;
107 if (Options.Verbosity >= 2)
108 Printf("Reload: read %zd new units.\n", AdditionalCorpus.size());
109 for (auto &X : AdditionalCorpus) {
110 if (X.size() > (size_t)Options.MaxLen)
111 X.resize(Options.MaxLen);
112 if (UnitHashesAddedToCorpus.insert(Hash(X)).second) {
114 CurrentUnit.insert(CurrentUnit.begin(), X.begin(), X.end());
115 size_t NewCoverage = RunOne(CurrentUnit);
118 if (Options.Verbosity >= 1)
119 PrintStats("RELOAD", NewCoverage);
125 void Fuzzer::ShuffleAndMinimize() {
127 bool PreferSmall = (Options.PreferSmallDuringInitialShuffle == 1 ||
128 (Options.PreferSmallDuringInitialShuffle == -1 &&
129 USF.GetRand().RandBool()));
130 if (Options.Verbosity)
131 Printf("PreferSmall: %d\n", PreferSmall);
132 PrintStats("READ ", 0);
133 std::vector<Unit> NewCorpus;
134 if (Options.ShuffleAtStartUp) {
135 std::random_shuffle(Corpus.begin(), Corpus.end(), USF.GetRand());
138 Corpus.begin(), Corpus.end(),
139 [](const Unit &A, const Unit &B) { return A.size() < B.size(); });
141 Unit &U = CurrentUnit;
142 for (const auto &C : Corpus) {
143 for (size_t First = 0; First < 1; First++) {
145 size_t Last = std::min(First + Options.MaxLen, C.size());
146 U.insert(U.begin(), C.begin() + First, C.begin() + Last);
147 if (Options.OnlyASCII)
149 size_t NewCoverage = RunOne(U);
151 MaxCov = NewCoverage;
152 NewCorpus.push_back(U);
153 if (Options.Verbosity >= 2)
154 Printf("NEW0: %zd L %zd\n", NewCoverage, U.size());
159 for (auto &X : Corpus)
160 UnitHashesAddedToCorpus.insert(Hash(X));
161 PrintStats("INITED", MaxCov);
164 size_t Fuzzer::RunOne(const Unit &U) {
165 UnitStartTime = system_clock::now();
167 size_t Res = RunOneMaximizeTotalCoverage(U);
168 auto UnitStopTime = system_clock::now();
170 duration_cast<seconds>(UnitStopTime - UnitStartTime).count();
171 if (TimeOfUnit > TimeOfLongestUnitInSeconds &&
172 TimeOfUnit >= Options.ReportSlowUnits) {
173 TimeOfLongestUnitInSeconds = TimeOfUnit;
174 Printf("Slowest unit: %zd s:\n", TimeOfLongestUnitInSeconds);
175 WriteUnitToFileWithPrefix(U, "slow-unit-");
180 void Fuzzer::RunOneAndUpdateCorpus(Unit &U) {
181 if (TotalNumberOfRuns >= Options.MaxNumberOfRuns)
183 if (Options.OnlyASCII)
185 ReportNewCoverage(RunOne(U), U);
188 void Fuzzer::ExecuteCallback(const Unit &U) {
189 int Res = USF.TargetFunction(U.data(), U.size());
194 size_t Fuzzer::RunOneMaximizeTotalCoverage(const Unit &U) {
195 size_t NumCounters = __sanitizer_get_number_of_counters();
196 if (Options.UseCounters) {
197 CounterBitmap.resize(NumCounters);
198 __sanitizer_update_counter_bitset_and_clear_counters(0);
200 size_t OldCoverage = __sanitizer_get_total_unique_coverage();
202 size_t NewCoverage = __sanitizer_get_total_unique_coverage();
203 size_t NumNewBits = 0;
204 if (Options.UseCounters)
205 NumNewBits = __sanitizer_update_counter_bitset_and_clear_counters(
206 CounterBitmap.data());
208 if (!(TotalNumberOfRuns & (TotalNumberOfRuns - 1)) && Options.Verbosity)
209 PrintStats("pulse ", NewCoverage);
211 if (NewCoverage > OldCoverage || NumNewBits)
216 void Fuzzer::WriteToOutputCorpus(const Unit &U) {
217 if (Options.OutputCorpus.empty()) return;
218 std::string Path = DirPlusFile(Options.OutputCorpus, Hash(U));
219 WriteToFile(U, Path);
220 if (Options.Verbosity >= 2)
221 Printf("Written to %s\n", Path.c_str());
222 assert(!Options.OnlyASCII || IsASCII(U));
225 void Fuzzer::WriteUnitToFileWithPrefix(const Unit &U, const char *Prefix) {
226 if (!Options.SaveArtifacts)
228 std::string Path = Options.ArtifactPrefix + Prefix + Hash(U);
229 WriteToFile(U, Path);
230 Printf("artifact_prefix='%s'; Test unit written to %s\n",
231 Options.ArtifactPrefix.c_str(), Path.c_str());
232 if (U.size() <= kMaxUnitSizeToPrint) {
234 PrintFileAsBase64(Path);
238 void Fuzzer::SaveCorpus() {
239 if (Options.OutputCorpus.empty()) return;
240 for (const auto &U : Corpus)
241 WriteToFile(U, DirPlusFile(Options.OutputCorpus, Hash(U)));
242 if (Options.Verbosity)
243 Printf("Written corpus of %zd files to %s\n", Corpus.size(),
244 Options.OutputCorpus.c_str());
247 void Fuzzer::ReportNewCoverage(size_t NewCoverage, const Unit &U) {
248 if (!NewCoverage) return;
250 UnitHashesAddedToCorpus.insert(Hash(U));
251 PrintStats("NEW ", NewCoverage, "");
252 if (Options.Verbosity) {
253 Printf(" L: %zd", U.size());
256 PrintUnitInASCII(U, "\t");
261 WriteToOutputCorpus(U);
262 if (Options.ExitOnFirst)
266 void Fuzzer::MutateAndTestOne(Unit *U) {
267 for (int i = 0; i < Options.MutateDepth; i++) {
268 StartTraceRecording();
269 size_t Size = U->size();
270 U->resize(Options.MaxLen);
271 size_t NewSize = USF.Mutate(U->data(), Size, U->size());
272 assert(NewSize > 0 && "Mutator returned empty unit");
273 assert(NewSize <= (size_t)Options.MaxLen &&
274 "Mutator return overisized unit");
276 RunOneAndUpdateCorpus(*U);
277 size_t NumTraceBasedMutations = StopTraceRecording();
279 std::min((size_t)Options.TBMWidth, NumTraceBasedMutations);
281 std::min((size_t)Options.TBMDepth, NumTraceBasedMutations);
283 for (size_t w = 0; w < TBMWidth; w++) {
285 for (size_t d = 0; d < TBMDepth; d++) {
286 TotalNumberOfExecutedTraceBasedMutations++;
287 ApplyTraceBasedMutation(USF.GetRand()(NumTraceBasedMutations), U);
288 RunOneAndUpdateCorpus(*U);
294 void Fuzzer::Loop() {
295 for (auto &U: Options.Dictionary)
296 USF.GetMD().AddWordToDictionary(U.data(), U.size());
299 for (size_t J1 = 0; J1 < Corpus.size(); J1++) {
301 RereadOutputCorpus();
302 if (TotalNumberOfRuns >= Options.MaxNumberOfRuns)
304 if (Options.MaxTotalTimeSec > 0 &&
305 secondsSinceProcessStartUp() >
306 static_cast<size_t>(Options.MaxTotalTimeSec))
308 CurrentUnit = Corpus[J1];
309 // Optionally, cross with another unit.
310 if (Options.DoCrossOver && USF.GetRand().RandBool()) {
311 size_t J2 = USF.GetRand()(Corpus.size());
312 if (!Corpus[J1].empty() && !Corpus[J2].empty()) {
313 assert(!Corpus[J2].empty());
314 CurrentUnit.resize(Options.MaxLen);
315 size_t NewSize = USF.CrossOver(
316 Corpus[J1].data(), Corpus[J1].size(), Corpus[J2].data(),
317 Corpus[J2].size(), CurrentUnit.data(), CurrentUnit.size());
318 assert(NewSize > 0 && "CrossOver returned empty unit");
319 assert(NewSize <= (size_t)Options.MaxLen &&
320 "CrossOver returned overisized unit");
321 CurrentUnit.resize(NewSize);
324 // Perform several mutations and runs.
325 MutateAndTestOne(&CurrentUnit);
330 void Fuzzer::SyncCorpus() {
331 if (Options.SyncCommand.empty() || Options.OutputCorpus.empty()) return;
332 auto Now = system_clock::now();
333 if (duration_cast<seconds>(Now - LastExternalSync).count() <
336 LastExternalSync = Now;
337 ExecuteCommand(Options.SyncCommand + " " + Options.OutputCorpus);
340 } // namespace fuzzer