339 lines
		
	
	
		
			11 KiB
		
	
	
	
		
			C++
		
	
	
	
			
		
		
	
	
			339 lines
		
	
	
		
			11 KiB
		
	
	
	
		
			C++
		
	
	
	
//===- FuzzerMerge.cpp - merging corpora ----------------------------------===//
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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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// Merging corpora.
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//===----------------------------------------------------------------------===//
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#include "FuzzerInternal.h"
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#include "FuzzerIO.h"
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#include "FuzzerMerge.h"
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#include "FuzzerTracePC.h"
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#include "FuzzerUtil.h"
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#include <fstream>
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#include <iterator>
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#include <set>
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#include <sstream>
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namespace fuzzer {
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bool Merger::Parse(const std::string &Str, bool ParseCoverage) {
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  std::istringstream SS(Str);
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  return Parse(SS, ParseCoverage);
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}
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void Merger::ParseOrExit(std::istream &IS, bool ParseCoverage) {
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  if (!Parse(IS, ParseCoverage)) {
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    Printf("MERGE: failed to parse the control file (unexpected error)\n");
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    exit(1);
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  }
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}
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// The control file example:
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//
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// 3 # The number of inputs
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// 1 # The number of inputs in the first corpus, <= the previous number
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// file0
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// file1
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// file2  # One file name per line.
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// STARTED 0 123  # FileID, file size
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// DONE 0 1 4 6 8  # FileID COV1 COV2 ...
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// STARTED 1 456  # If DONE is missing, the input crashed while processing.
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// STARTED 2 567
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// DONE 2 8 9
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bool Merger::Parse(std::istream &IS, bool ParseCoverage) {
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  LastFailure.clear();
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  std::string Line;
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  // Parse NumFiles.
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  if (!std::getline(IS, Line, '\n')) return false;
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  std::istringstream L1(Line);
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  size_t NumFiles = 0;
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  L1 >> NumFiles;
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  if (NumFiles == 0 || NumFiles > 10000000) return false;
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  // Parse NumFilesInFirstCorpus.
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  if (!std::getline(IS, Line, '\n')) return false;
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  std::istringstream L2(Line);
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  NumFilesInFirstCorpus = NumFiles + 1;
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  L2 >> NumFilesInFirstCorpus;
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  if (NumFilesInFirstCorpus > NumFiles) return false;
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  // Parse file names.
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  Files.resize(NumFiles);
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  for (size_t i = 0; i < NumFiles; i++)
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    if (!std::getline(IS, Files[i].Name, '\n'))
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      return false;
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  // Parse STARTED and DONE lines.
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  size_t ExpectedStartMarker = 0;
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  const size_t kInvalidStartMarker = -1;
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  size_t LastSeenStartMarker = kInvalidStartMarker;
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  std::vector<uint32_t> TmpFeatures;
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  while (std::getline(IS, Line, '\n')) {
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    std::istringstream ISS1(Line);
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    std::string Marker;
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    size_t N;
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    ISS1 >> Marker;
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    ISS1 >> N;
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    if (Marker == "STARTED") {
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      // STARTED FILE_ID FILE_SIZE
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      if (ExpectedStartMarker != N)
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        return false;
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      ISS1 >> Files[ExpectedStartMarker].Size;
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      LastSeenStartMarker = ExpectedStartMarker;
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      assert(ExpectedStartMarker < Files.size());
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      ExpectedStartMarker++;
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    } else if (Marker == "DONE") {
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      // DONE FILE_ID COV1 COV2 COV3 ...
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      size_t CurrentFileIdx = N;
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      if (CurrentFileIdx != LastSeenStartMarker)
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        return false;
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      LastSeenStartMarker = kInvalidStartMarker;
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      if (ParseCoverage) {
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        TmpFeatures.clear();  // use a vector from outer scope to avoid resizes.
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        while (ISS1 >> std::hex >> N)
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          TmpFeatures.push_back(N);
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        std::sort(TmpFeatures.begin(), TmpFeatures.end());
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        Files[CurrentFileIdx].Features = TmpFeatures;
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      }
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    } else {
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      return false;
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    }
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  }
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  if (LastSeenStartMarker != kInvalidStartMarker)
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    LastFailure = Files[LastSeenStartMarker].Name;
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  FirstNotProcessedFile = ExpectedStartMarker;
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  return true;
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}
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size_t Merger::ApproximateMemoryConsumption() const  {
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  size_t Res = 0;
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  for (const auto &F: Files)
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    Res += sizeof(F) + F.Features.size() * sizeof(F.Features[0]);
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  return Res;
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}
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// Decides which files need to be merged (add thost to NewFiles).
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// Returns the number of new features added.
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size_t Merger::Merge(const std::set<uint32_t> &InitialFeatures,
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                     std::vector<std::string> *NewFiles) {
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  NewFiles->clear();
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  assert(NumFilesInFirstCorpus <= Files.size());
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  std::set<uint32_t> AllFeatures(InitialFeatures);
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  // What features are in the initial corpus?
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  for (size_t i = 0; i < NumFilesInFirstCorpus; i++) {
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    auto &Cur = Files[i].Features;
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    AllFeatures.insert(Cur.begin(), Cur.end());
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  }
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  size_t InitialNumFeatures = AllFeatures.size();
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  // Remove all features that we already know from all other inputs.
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  for (size_t i = NumFilesInFirstCorpus; i < Files.size(); i++) {
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    auto &Cur = Files[i].Features;
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    std::vector<uint32_t> Tmp;
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    std::set_difference(Cur.begin(), Cur.end(), AllFeatures.begin(),
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                        AllFeatures.end(), std::inserter(Tmp, Tmp.begin()));
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    Cur.swap(Tmp);
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  }
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  // Sort. Give preference to
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  //   * smaller files
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  //   * files with more features.
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  std::sort(Files.begin() + NumFilesInFirstCorpus, Files.end(),
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            [&](const MergeFileInfo &a, const MergeFileInfo &b) -> bool {
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              if (a.Size != b.Size)
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                return a.Size < b.Size;
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              return a.Features.size() > b.Features.size();
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            });
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  // One greedy pass: add the file's features to AllFeatures.
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  // If new features were added, add this file to NewFiles.
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  for (size_t i = NumFilesInFirstCorpus; i < Files.size(); i++) {
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    auto &Cur = Files[i].Features;
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    // Printf("%s -> sz %zd ft %zd\n", Files[i].Name.c_str(),
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    //       Files[i].Size, Cur.size());
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    size_t OldSize = AllFeatures.size();
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    AllFeatures.insert(Cur.begin(), Cur.end());
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    if (AllFeatures.size() > OldSize)
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      NewFiles->push_back(Files[i].Name);
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  }
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  return AllFeatures.size() - InitialNumFeatures;
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}
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void Merger::PrintSummary(std::ostream &OS) {
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  for (auto &File : Files) {
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    OS << std::hex;
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    OS << File.Name << " size: " << File.Size << " features: ";
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    for (auto Feature : File.Features)
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      OS << " " << Feature;
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    OS << "\n";
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  }
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}
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std::set<uint32_t> Merger::AllFeatures() const {
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  std::set<uint32_t> S;
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  for (auto &File : Files)
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    S.insert(File.Features.begin(), File.Features.end());
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  return S;
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}
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std::set<uint32_t> Merger::ParseSummary(std::istream &IS) {
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  std::string Line, Tmp;
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  std::set<uint32_t> Res;
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  while (std::getline(IS, Line, '\n')) {
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    size_t N;
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    std::istringstream ISS1(Line);
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    ISS1 >> Tmp;  // Name
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    ISS1 >> Tmp;  // size:
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    assert(Tmp == "size:" && "Corrupt summary file");
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    ISS1 >> std::hex;
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    ISS1 >> N;    // File Size
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    ISS1 >> Tmp;  // features:
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    assert(Tmp == "features:" && "Corrupt summary file");
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    while (ISS1 >> std::hex >> N)
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      Res.insert(N);
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  }
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  return Res;
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}
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// Inner process. May crash if the target crashes.
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void Fuzzer::CrashResistantMergeInternalStep(const std::string &CFPath) {
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  Printf("MERGE-INNER: using the control file '%s'\n", CFPath.c_str());
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  Merger M;
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  std::ifstream IF(CFPath);
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  M.ParseOrExit(IF, false);
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  IF.close();
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  if (!M.LastFailure.empty())
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    Printf("MERGE-INNER: '%s' caused a failure at the previous merge step\n",
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           M.LastFailure.c_str());
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  Printf("MERGE-INNER: %zd total files;"
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         " %zd processed earlier; will process %zd files now\n",
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         M.Files.size(), M.FirstNotProcessedFile,
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         M.Files.size() - M.FirstNotProcessedFile);
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  std::ofstream OF(CFPath, std::ofstream::out | std::ofstream::app);
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  for (size_t i = M.FirstNotProcessedFile; i < M.Files.size(); i++) {
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    auto U = FileToVector(M.Files[i].Name);
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    if (U.size() > MaxInputLen) {
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      U.resize(MaxInputLen);
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      U.shrink_to_fit();
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    }
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    std::ostringstream StartedLine;
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    // Write the pre-run marker.
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    OF << "STARTED " << std::dec << i << " " << U.size() << "\n";
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    OF.flush();  // Flush is important since ExecuteCommand may crash.
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    // Run.
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    TPC.ResetMaps();
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    ExecuteCallback(U.data(), U.size());
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    // Collect coverage.
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    std::set<size_t> Features;
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    TPC.CollectFeatures([&](size_t Feature) -> bool {
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      Features.insert(Feature);
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      return true;
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    });
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    // Show stats.
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    TotalNumberOfRuns++;
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    if (!(TotalNumberOfRuns & (TotalNumberOfRuns - 1)))
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      PrintStats("pulse ");
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    // Write the post-run marker and the coverage.
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    OF << "DONE " << i;
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    for (size_t F : Features)
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      OF << " " << std::hex << F;
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    OF << "\n";
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  }
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}
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// Outer process. Does not call the target code and thus sohuld not fail.
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void Fuzzer::CrashResistantMerge(const std::vector<std::string> &Args,
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                                 const std::vector<std::string> &Corpora,
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                                 const char *CoverageSummaryInputPathOrNull,
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                                 const char *CoverageSummaryOutputPathOrNull) {
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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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  std::vector<std::string> AllFiles;
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  ListFilesInDirRecursive(Corpora[0], nullptr, &AllFiles, /*TopDir*/true);
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  size_t NumFilesInFirstCorpus = AllFiles.size();
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  for (size_t i = 1; i < Corpora.size(); i++)
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    ListFilesInDirRecursive(Corpora[i], nullptr, &AllFiles, /*TopDir*/true);
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  Printf("MERGE-OUTER: %zd files, %zd in the initial corpus\n",
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         AllFiles.size(), NumFilesInFirstCorpus);
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  auto CFPath = DirPlusFile(TmpDir(),
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                       "libFuzzerTemp." + std::to_string(GetPid()) + ".txt");
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  // Write the control file.
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  RemoveFile(CFPath);
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  std::ofstream ControlFile(CFPath);
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  ControlFile << AllFiles.size() << "\n";
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  ControlFile << NumFilesInFirstCorpus << "\n";
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  for (auto &Path: AllFiles)
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    ControlFile << Path << "\n";
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  if (!ControlFile) {
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    Printf("MERGE-OUTER: failed to write to the control file: %s\n",
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           CFPath.c_str());
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    exit(1);
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  }
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  ControlFile.close();
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  // Execute the inner process untill it passes.
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  // Every inner process should execute at least one input.
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  std::string BaseCmd = CloneArgsWithoutX(Args, "keep-all-flags");
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  bool Success = false;
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  for (size_t i = 1; i <= AllFiles.size(); i++) {
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    Printf("MERGE-OUTER: attempt %zd\n", i);
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    auto ExitCode =
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        ExecuteCommand(BaseCmd + " -merge_control_file=" + CFPath);
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    if (!ExitCode) {
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      Printf("MERGE-OUTER: succesfull in %zd attempt(s)\n", i);
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      Success = true;
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      break;
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    }
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  }
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  if (!Success) {
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    Printf("MERGE-OUTER: zero succesfull attempts, exiting\n");
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    exit(1);
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  }
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  // Read the control file and do the merge.
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  Merger M;
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  std::ifstream IF(CFPath);
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  IF.seekg(0, IF.end);
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  Printf("MERGE-OUTER: the control file has %zd bytes\n", (size_t)IF.tellg());
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  IF.seekg(0, IF.beg);
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  M.ParseOrExit(IF, true);
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  IF.close();
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  Printf("MERGE-OUTER: consumed %zdMb (%zdMb rss) to parse the control file\n",
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         M.ApproximateMemoryConsumption() >> 20, GetPeakRSSMb());
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  if (CoverageSummaryOutputPathOrNull) {
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    Printf("MERGE-OUTER: writing coverage summary for %zd files to %s\n",
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           M.Files.size(), CoverageSummaryOutputPathOrNull);
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    std::ofstream SummaryOut(CoverageSummaryOutputPathOrNull);
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    M.PrintSummary(SummaryOut);
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  }
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  std::vector<std::string> NewFiles;
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  std::set<uint32_t> InitialFeatures;
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  if (CoverageSummaryInputPathOrNull) {
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    std::ifstream SummaryIn(CoverageSummaryInputPathOrNull);
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    InitialFeatures = M.ParseSummary(SummaryIn);
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    Printf("MERGE-OUTER: coverage summary loaded from %s, %zd features found\n",
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           CoverageSummaryInputPathOrNull, InitialFeatures.size());
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  }
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  size_t NumNewFeatures = M.Merge(InitialFeatures, &NewFiles);
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  Printf("MERGE-OUTER: %zd new files with %zd new features added\n",
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         NewFiles.size(), NumNewFeatures);
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  for (auto &F: NewFiles)
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    WriteToOutputCorpus(FileToVector(F));
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  // We are done, delete the control file.
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  RemoveFile(CFPath);
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}
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} // namespace fuzzer
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