forked from OSchip/llvm-project
510 lines
16 KiB
C++
510 lines
16 KiB
C++
//===- FuzzerLoop.cpp - Fuzzer's main loop --------------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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// Fuzzer's main loop.
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//===----------------------------------------------------------------------===//
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#include "FuzzerInternal.h"
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#include <algorithm>
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#if defined(__has_include)
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# if __has_include(<sanitizer/coverage_interface.h>)
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# include <sanitizer/coverage_interface.h>
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# endif
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#endif
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extern "C" {
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// Re-declare some of the sanitizer functions as "weak" so that
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// libFuzzer can be linked w/o the sanitizers and sanitizer-coverage
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// (in which case it will complain at start-up time).
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__attribute__((weak)) void __sanitizer_print_stack_trace();
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__attribute__((weak)) void __sanitizer_reset_coverage();
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__attribute__((weak)) size_t __sanitizer_get_total_unique_caller_callee_pairs();
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__attribute__((weak)) size_t __sanitizer_get_total_unique_coverage();
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__attribute__((weak))
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void __sanitizer_set_death_callback(void (*callback)(void));
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__attribute__((weak)) size_t __sanitizer_get_number_of_counters();
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__attribute__((weak))
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uintptr_t __sanitizer_update_counter_bitset_and_clear_counters(uint8_t *bitset);
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__attribute__((weak)) uintptr_t
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__sanitizer_get_coverage_pc_buffer(uintptr_t **data);
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}
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namespace fuzzer {
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static const size_t kMaxUnitSizeToPrint = 256;
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static void MissingWeakApiFunction(const char *FnName) {
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Printf("ERROR: %s is not defined. Exiting.\n"
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"Did you use -fsanitize-coverage=... to build your code?\n", FnName);
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exit(1);
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}
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#define CHECK_WEAK_API_FUNCTION(fn) \
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do { \
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if (!fn) \
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MissingWeakApiFunction(#fn); \
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} while (false)
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// Only one Fuzzer per process.
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static Fuzzer *F;
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Fuzzer::Fuzzer(UserSuppliedFuzzer &USF, FuzzingOptions Options)
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: USF(USF), Options(Options) {
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SetDeathCallback();
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InitializeTraceState();
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assert(!F);
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F = this;
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}
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void Fuzzer::SetDeathCallback() {
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CHECK_WEAK_API_FUNCTION(__sanitizer_set_death_callback);
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__sanitizer_set_death_callback(StaticDeathCallback);
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}
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void Fuzzer::PrintUnitInASCII(const Unit &U, const char *PrintAfter) {
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PrintASCII(U, PrintAfter);
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}
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void Fuzzer::StaticDeathCallback() {
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assert(F);
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F->DeathCallback();
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}
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void Fuzzer::DeathCallback() {
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Printf("DEATH:\n");
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if (CurrentUnit.size() <= kMaxUnitSizeToPrint) {
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Print(CurrentUnit, "\n");
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PrintUnitInASCII(CurrentUnit, "\n");
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}
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WriteUnitToFileWithPrefix(CurrentUnit, "crash-");
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}
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void Fuzzer::StaticAlarmCallback() {
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assert(F);
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F->AlarmCallback();
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}
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void Fuzzer::AlarmCallback() {
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assert(Options.UnitTimeoutSec > 0);
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size_t Seconds =
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duration_cast<seconds>(system_clock::now() - UnitStartTime).count();
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if (Seconds == 0) return;
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if (Options.Verbosity >= 2)
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Printf("AlarmCallback %zd\n", Seconds);
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if (Seconds >= (size_t)Options.UnitTimeoutSec) {
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Printf("ALARM: working on the last Unit for %zd seconds\n", Seconds);
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Printf(" and the timeout value is %d (use -timeout=N to change)\n",
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Options.UnitTimeoutSec);
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if (CurrentUnit.size() <= kMaxUnitSizeToPrint) {
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Print(CurrentUnit, "\n");
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PrintUnitInASCII(CurrentUnit, "\n");
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}
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WriteUnitToFileWithPrefix(CurrentUnit, "timeout-");
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Printf("==%d== ERROR: libFuzzer: timeout after %d seconds\n", GetPid(),
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Seconds);
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if (__sanitizer_print_stack_trace)
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__sanitizer_print_stack_trace();
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Printf("SUMMARY: libFuzzer: timeout\n");
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exit(1);
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}
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}
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void Fuzzer::PrintStats(const char *Where, const char *End) {
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size_t Seconds = secondsSinceProcessStartUp();
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size_t ExecPerSec = (Seconds ? TotalNumberOfRuns / Seconds : 0);
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if (Options.OutputCSV) {
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static bool csvHeaderPrinted = false;
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if (!csvHeaderPrinted) {
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csvHeaderPrinted = true;
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Printf("runs,block_cov,bits,cc_cov,corpus,execs_per_sec,tbms,reason\n");
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}
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Printf("%zd,%zd,%zd,%zd,%zd,%zd,%zd,%s\n", TotalNumberOfRuns,
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LastRecordedBlockCoverage, TotalBits(),
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LastRecordedCallerCalleeCoverage, Corpus.size(), ExecPerSec,
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TotalNumberOfExecutedTraceBasedMutations, Where);
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}
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if (!Options.Verbosity)
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return;
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Printf("#%zd\t%s", TotalNumberOfRuns, Where);
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if (LastRecordedBlockCoverage)
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Printf(" cov: %zd", LastRecordedBlockCoverage);
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if (auto TB = TotalBits())
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Printf(" bits: %zd", TB);
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if (LastRecordedCallerCalleeCoverage)
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Printf(" indir: %zd", LastRecordedCallerCalleeCoverage);
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Printf(" units: %zd exec/s: %zd", Corpus.size(), ExecPerSec);
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if (TotalNumberOfExecutedTraceBasedMutations)
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Printf(" tbm: %zd", TotalNumberOfExecutedTraceBasedMutations);
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Printf("%s", End);
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}
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void Fuzzer::RereadOutputCorpus() {
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if (Options.OutputCorpus.empty()) return;
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std::vector<Unit> AdditionalCorpus;
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ReadDirToVectorOfUnits(Options.OutputCorpus.c_str(), &AdditionalCorpus,
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&EpochOfLastReadOfOutputCorpus);
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if (Corpus.empty()) {
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Corpus = AdditionalCorpus;
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return;
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}
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if (!Options.Reload) return;
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if (Options.Verbosity >= 2)
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Printf("Reload: read %zd new units.\n", AdditionalCorpus.size());
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for (auto &X : AdditionalCorpus) {
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if (X.size() > (size_t)Options.MaxLen)
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X.resize(Options.MaxLen);
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if (UnitHashesAddedToCorpus.insert(Hash(X)).second) {
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CurrentUnit.clear();
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CurrentUnit.insert(CurrentUnit.begin(), X.begin(), X.end());
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if (RunOne(CurrentUnit)) {
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Corpus.push_back(X);
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PrintStats("RELOAD");
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}
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}
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}
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}
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void Fuzzer::ShuffleAndMinimize() {
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bool PreferSmall = (Options.PreferSmallDuringInitialShuffle == 1 ||
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(Options.PreferSmallDuringInitialShuffle == -1 &&
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USF.GetRand().RandBool()));
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if (Options.Verbosity)
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Printf("PreferSmall: %d\n", PreferSmall);
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PrintStats("READ ");
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std::vector<Unit> NewCorpus;
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if (Options.ShuffleAtStartUp) {
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std::random_shuffle(Corpus.begin(), Corpus.end(), USF.GetRand());
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if (PreferSmall)
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std::stable_sort(
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Corpus.begin(), Corpus.end(),
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[](const Unit &A, const Unit &B) { return A.size() < B.size(); });
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}
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Unit &U = CurrentUnit;
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for (const auto &C : Corpus) {
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for (size_t First = 0; First < 1; First++) {
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U.clear();
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size_t Last = std::min(First + Options.MaxLen, C.size());
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U.insert(U.begin(), C.begin() + First, C.begin() + Last);
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if (Options.OnlyASCII)
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ToASCII(U);
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if (RunOne(U)) {
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NewCorpus.push_back(U);
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if (Options.Verbosity >= 2)
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Printf("NEW0: %zd L %zd\n", LastRecordedBlockCoverage, U.size());
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}
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}
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}
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Corpus = NewCorpus;
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for (auto &X : Corpus)
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UnitHashesAddedToCorpus.insert(Hash(X));
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PrintStats("INITED");
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}
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bool Fuzzer::RunOne(const Unit &U) {
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UnitStartTime = system_clock::now();
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TotalNumberOfRuns++;
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PrepareCoverageBeforeRun();
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ExecuteCallback(U);
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bool Res = CheckCoverageAfterRun();
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auto UnitStopTime = system_clock::now();
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auto TimeOfUnit =
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duration_cast<seconds>(UnitStopTime - UnitStartTime).count();
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if (!(TotalNumberOfRuns & (TotalNumberOfRuns - 1)) &&
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secondsSinceProcessStartUp() >= 2)
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PrintStats("pulse ");
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if (TimeOfUnit > TimeOfLongestUnitInSeconds &&
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TimeOfUnit >= Options.ReportSlowUnits) {
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TimeOfLongestUnitInSeconds = TimeOfUnit;
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Printf("Slowest unit: %zd s:\n", TimeOfLongestUnitInSeconds);
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WriteUnitToFileWithPrefix(U, "slow-unit-");
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}
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return Res;
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}
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void Fuzzer::RunOneAndUpdateCorpus(Unit &U) {
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if (TotalNumberOfRuns >= Options.MaxNumberOfRuns)
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return;
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if (Options.OnlyASCII)
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ToASCII(U);
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if (RunOne(U))
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ReportNewCoverage(U);
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}
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void Fuzzer::ExecuteCallback(const Unit &U) {
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const uint8_t *Data = U.data();
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uint8_t EmptyData;
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if (!Data)
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Data = &EmptyData;
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int Res = USF.TargetFunction(Data, U.size());
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(void)Res;
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assert(Res == 0);
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}
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size_t Fuzzer::RecordBlockCoverage() {
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CHECK_WEAK_API_FUNCTION(__sanitizer_get_total_unique_coverage);
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uintptr_t PrevCoverage = LastRecordedBlockCoverage;
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LastRecordedBlockCoverage = __sanitizer_get_total_unique_coverage();
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if (PrevCoverage == LastRecordedBlockCoverage || !Options.PrintNewCovPcs)
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return LastRecordedBlockCoverage;
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uintptr_t PrevBufferLen = LastCoveragePcBufferLen;
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uintptr_t *CoverageBuf;
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LastCoveragePcBufferLen = __sanitizer_get_coverage_pc_buffer(&CoverageBuf);
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assert(CoverageBuf);
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for (size_t i = PrevBufferLen; i < LastCoveragePcBufferLen; ++i) {
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Printf("0x%x\n", CoverageBuf[i]);
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}
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return LastRecordedBlockCoverage;
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}
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size_t Fuzzer::RecordCallerCalleeCoverage() {
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if (!Options.UseIndirCalls)
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return 0;
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if (!__sanitizer_get_total_unique_caller_callee_pairs)
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return 0;
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return LastRecordedCallerCalleeCoverage =
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__sanitizer_get_total_unique_caller_callee_pairs();
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}
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void Fuzzer::PrepareCoverageBeforeRun() {
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if (Options.UseCounters) {
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size_t NumCounters = __sanitizer_get_number_of_counters();
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CounterBitmap.resize(NumCounters);
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__sanitizer_update_counter_bitset_and_clear_counters(0);
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}
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RecordBlockCoverage();
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RecordCallerCalleeCoverage();
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}
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bool Fuzzer::CheckCoverageAfterRun() {
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size_t OldCoverage = LastRecordedBlockCoverage;
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size_t NewCoverage = RecordBlockCoverage();
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size_t OldCallerCalleeCoverage = LastRecordedCallerCalleeCoverage;
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size_t NewCallerCalleeCoverage = RecordCallerCalleeCoverage();
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size_t NumNewBits = 0;
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if (Options.UseCounters)
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NumNewBits = __sanitizer_update_counter_bitset_and_clear_counters(
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CounterBitmap.data());
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return NewCoverage > OldCoverage ||
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NewCallerCalleeCoverage > OldCallerCalleeCoverage || NumNewBits;
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}
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void Fuzzer::WriteToOutputCorpus(const Unit &U) {
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if (Options.OutputCorpus.empty()) return;
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std::string Path = DirPlusFile(Options.OutputCorpus, Hash(U));
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WriteToFile(U, Path);
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if (Options.Verbosity >= 2)
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Printf("Written to %s\n", Path.c_str());
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assert(!Options.OnlyASCII || IsASCII(U));
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}
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void Fuzzer::WriteUnitToFileWithPrefix(const Unit &U, const char *Prefix) {
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if (!Options.SaveArtifacts)
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return;
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std::string Path = Options.ArtifactPrefix + Prefix + Hash(U);
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if (!Options.ExactArtifactPath.empty())
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Path = Options.ExactArtifactPath; // Overrides ArtifactPrefix.
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WriteToFile(U, Path);
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Printf("artifact_prefix='%s'; Test unit written to %s\n",
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Options.ArtifactPrefix.c_str(), Path.c_str());
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if (U.size() <= kMaxUnitSizeToPrint)
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Printf("Base64: %s\n", Base64(U).c_str());
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}
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void Fuzzer::SaveCorpus() {
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if (Options.OutputCorpus.empty()) return;
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for (const auto &U : Corpus)
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WriteToFile(U, DirPlusFile(Options.OutputCorpus, Hash(U)));
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if (Options.Verbosity)
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Printf("Written corpus of %zd files to %s\n", Corpus.size(),
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Options.OutputCorpus.c_str());
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}
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void Fuzzer::PrintStatusForNewUnit(const Unit &U) {
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if (!Options.PrintNEW)
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return;
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PrintStats("NEW ", "");
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if (Options.Verbosity) {
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Printf(" L: %zd ", U.size());
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USF.PrintMutationSequence();
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Printf("\n");
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}
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}
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void Fuzzer::ReportNewCoverage(const Unit &U) {
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Corpus.push_back(U);
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UnitHashesAddedToCorpus.insert(Hash(U));
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PrintStatusForNewUnit(U);
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WriteToOutputCorpus(U);
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if (Options.ExitOnFirst)
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exit(0);
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}
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void Fuzzer::Merge(const std::vector<std::string> &Corpora) {
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if (Corpora.size() <= 1) {
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Printf("Merge requires two or more corpus dirs\n");
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return;
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}
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auto InitialCorpusDir = Corpora[0];
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ReadDir(InitialCorpusDir, nullptr);
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Printf("Merge: running the initial corpus '%s' of %d units\n",
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InitialCorpusDir.c_str(), Corpus.size());
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for (auto &U : Corpus)
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RunOne(U);
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std::vector<std::string> ExtraCorpora(Corpora.begin() + 1, Corpora.end());
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size_t NumTried = 0;
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size_t NumMerged = 0;
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for (auto &C : ExtraCorpora) {
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Corpus.clear();
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ReadDir(C, nullptr);
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Printf("Merge: merging the extra corpus '%s' of %zd units\n", C.c_str(),
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Corpus.size());
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for (auto &U : Corpus) {
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NumTried++;
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if (RunOne(U)) {
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WriteToOutputCorpus(U);
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NumMerged++;
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}
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}
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}
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Printf("Merge: written %zd out of %zd units\n", NumMerged, NumTried);
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}
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void Fuzzer::MutateAndTestOne() {
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auto &U = CurrentUnit;
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USF.StartMutationSequence();
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U = ChooseUnitToMutate();
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for (int i = 0; i < Options.MutateDepth; i++) {
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size_t Size = U.size();
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U.resize(Options.MaxLen);
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size_t NewSize = USF.Mutate(U.data(), Size, U.size());
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assert(NewSize > 0 && "Mutator returned empty unit");
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assert(NewSize <= (size_t)Options.MaxLen &&
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"Mutator return overisized unit");
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U.resize(NewSize);
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if (i == 0)
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StartTraceRecording();
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RunOneAndUpdateCorpus(U);
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StopTraceRecording();
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}
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}
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// Returns an index of random unit from the corpus to mutate.
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// Hypothesis: units added to the corpus last are more likely to be interesting.
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// This function gives more wieght to the more recent units.
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size_t Fuzzer::ChooseUnitIdxToMutate() {
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size_t N = Corpus.size();
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size_t Total = (N + 1) * N / 2;
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size_t R = USF.GetRand()(Total);
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size_t IdxBeg = 0, IdxEnd = N;
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// Binary search.
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while (IdxEnd - IdxBeg >= 2) {
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size_t Idx = IdxBeg + (IdxEnd - IdxBeg) / 2;
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if (R > (Idx + 1) * Idx / 2)
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IdxBeg = Idx;
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else
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IdxEnd = Idx;
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}
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assert(IdxBeg < N);
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return IdxBeg;
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}
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// Experimental search heuristic: drilling.
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// - Read, shuffle, execute and minimize the corpus.
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// - Choose one random unit.
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// - Reset the coverage.
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// - Start fuzzing as if the chosen unit was the only element of the corpus.
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// - When done, reset the coverage again.
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// - Merge the newly created corpus into the original one.
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void Fuzzer::Drill() {
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// The corpus is already read, shuffled, and minimized.
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assert(!Corpus.empty());
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Options.PrintNEW = false; // Don't print NEW status lines when drilling.
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Unit U = ChooseUnitToMutate();
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CHECK_WEAK_API_FUNCTION(__sanitizer_reset_coverage);
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__sanitizer_reset_coverage();
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std::vector<Unit> SavedCorpus;
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SavedCorpus.swap(Corpus);
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Corpus.push_back(U);
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assert(Corpus.size() == 1);
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RunOne(U);
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PrintStats("DRILL ");
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std::string SavedOutputCorpusPath; // Don't write new units while drilling.
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SavedOutputCorpusPath.swap(Options.OutputCorpus);
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Loop();
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__sanitizer_reset_coverage();
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PrintStats("REINIT");
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SavedOutputCorpusPath.swap(Options.OutputCorpus);
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for (auto &U : SavedCorpus)
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RunOne(U);
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PrintStats("MERGE ");
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Options.PrintNEW = true;
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size_t NumMerged = 0;
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for (auto &U : Corpus) {
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if (RunOne(U)) {
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PrintStatusForNewUnit(U);
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NumMerged++;
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WriteToOutputCorpus(U);
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}
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}
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PrintStats("MERGED");
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if (NumMerged && Options.Verbosity)
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Printf("Drilling discovered %zd new units\n", NumMerged);
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}
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void Fuzzer::Loop() {
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system_clock::time_point LastCorpusReload = system_clock::now();
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if (Options.DoCrossOver)
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USF.SetCorpus(&Corpus);
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while (true) {
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SyncCorpus();
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auto Now = system_clock::now();
|
|
if (duration_cast<seconds>(Now - LastCorpusReload).count()) {
|
|
RereadOutputCorpus();
|
|
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");
|
|
}
|
|
|
|
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
|