1//===- FuzzerDriver.cpp - FuzzerDriver function and flags -----------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8// FuzzerDriver and flag parsing.
9//===----------------------------------------------------------------------===//
10
11#include "FuzzerCommand.h"
12#include "FuzzerCorpus.h"
13#include "FuzzerFork.h"
14#include "FuzzerIO.h"
15#include "FuzzerInterface.h"
16#include "FuzzerInternal.h"
17#include "FuzzerMerge.h"
18#include "FuzzerMutate.h"
19#include "FuzzerPlatform.h"
20#include "FuzzerRandom.h"
21#include "FuzzerTracePC.h"
22#include <algorithm>
23#include <atomic>
24#include <chrono>
25#include <cstdlib>
26#include <cstring>
27#include <mutex>
28#include <string>
29#include <thread>
30#include <fstream>
31
32// This function should be present in the libFuzzer so that the client
33// binary can test for its existence.
34#if LIBFUZZER_MSVC
35extern "C" void __libfuzzer_is_present() {}
36#pragma comment(linker, "/include:__libfuzzer_is_present")
37#else
38extern "C" __attribute__((used)) void __libfuzzer_is_present() {}
39#endif  // LIBFUZZER_MSVC
40
41namespace fuzzer {
42
43// Program arguments.
44struct FlagDescription {
45  const char *Name;
46  const char *Description;
47  int   Default;
48  int   *IntFlag;
49  const char **StrFlag;
50  unsigned int *UIntFlag;
51};
52
53struct {
54#define FUZZER_DEPRECATED_FLAG(Name)
55#define FUZZER_FLAG_INT(Name, Default, Description) int Name;
56#define FUZZER_FLAG_UNSIGNED(Name, Default, Description) unsigned int Name;
57#define FUZZER_FLAG_STRING(Name, Description) const char *Name;
58#include "FuzzerFlags.def"
59#undef FUZZER_DEPRECATED_FLAG
60#undef FUZZER_FLAG_INT
61#undef FUZZER_FLAG_UNSIGNED
62#undef FUZZER_FLAG_STRING
63} Flags;
64
65static const FlagDescription FlagDescriptions [] {
66#define FUZZER_DEPRECATED_FLAG(Name)                                           \
67  {#Name, "Deprecated; don't use", 0, nullptr, nullptr, nullptr},
68#define FUZZER_FLAG_INT(Name, Default, Description)                            \
69  {#Name, Description, Default, &Flags.Name, nullptr, nullptr},
70#define FUZZER_FLAG_UNSIGNED(Name, Default, Description)                       \
71  {#Name,   Description, static_cast<int>(Default),                            \
72   nullptr, nullptr, &Flags.Name},
73#define FUZZER_FLAG_STRING(Name, Description)                                  \
74  {#Name, Description, 0, nullptr, &Flags.Name, nullptr},
75#include "FuzzerFlags.def"
76#undef FUZZER_DEPRECATED_FLAG
77#undef FUZZER_FLAG_INT
78#undef FUZZER_FLAG_UNSIGNED
79#undef FUZZER_FLAG_STRING
80};
81
82static const size_t kNumFlags =
83    sizeof(FlagDescriptions) / sizeof(FlagDescriptions[0]);
84
85static Vector<std::string> *Inputs;
86static std::string *ProgName;
87
88static void PrintHelp() {
89  Printf("Usage:\n");
90  auto Prog = ProgName->c_str();
91  Printf("\nTo run fuzzing pass 0 or more directories.\n");
92  Printf("%s [-flag1=val1 [-flag2=val2 ...] ] [dir1 [dir2 ...] ]\n", Prog);
93
94  Printf("\nTo run individual tests without fuzzing pass 1 or more files:\n");
95  Printf("%s [-flag1=val1 [-flag2=val2 ...] ] file1 [file2 ...]\n", Prog);
96
97  Printf("\nFlags: (strictly in form -flag=value)\n");
98  size_t MaxFlagLen = 0;
99  for (size_t F = 0; F < kNumFlags; F++)
100    MaxFlagLen = std::max(strlen(FlagDescriptions[F].Name), MaxFlagLen);
101
102  for (size_t F = 0; F < kNumFlags; F++) {
103    const auto &D = FlagDescriptions[F];
104    if (strstr(D.Description, "internal flag") == D.Description) continue;
105    Printf(" %s", D.Name);
106    for (size_t i = 0, n = MaxFlagLen - strlen(D.Name); i < n; i++)
107      Printf(" ");
108    Printf("\t");
109    Printf("%d\t%s\n", D.Default, D.Description);
110  }
111  Printf("\nFlags starting with '--' will be ignored and "
112            "will be passed verbatim to subprocesses.\n");
113}
114
115static const char *FlagValue(const char *Param, const char *Name) {
116  size_t Len = strlen(Name);
117  if (Param[0] == '-' && strstr(Param + 1, Name) == Param + 1 &&
118      Param[Len + 1] == '=')
119      return &Param[Len + 2];
120  return nullptr;
121}
122
123// Avoid calling stol as it triggers a bug in clang/glibc build.
124static long MyStol(const char *Str) {
125  long Res = 0;
126  long Sign = 1;
127  if (*Str == '-') {
128    Str++;
129    Sign = -1;
130  }
131  for (size_t i = 0; Str[i]; i++) {
132    char Ch = Str[i];
133    if (Ch < '0' || Ch > '9')
134      return Res;
135    Res = Res * 10 + (Ch - '0');
136  }
137  return Res * Sign;
138}
139
140static bool ParseOneFlag(const char *Param) {
141  if (Param[0] != '-') return false;
142  if (Param[1] == '-') {
143    static bool PrintedWarning = false;
144    if (!PrintedWarning) {
145      PrintedWarning = true;
146      Printf("INFO: libFuzzer ignores flags that start with '--'\n");
147    }
148    for (size_t F = 0; F < kNumFlags; F++)
149      if (FlagValue(Param + 1, FlagDescriptions[F].Name))
150        Printf("WARNING: did you mean '%s' (single dash)?\n", Param + 1);
151    return true;
152  }
153  for (size_t F = 0; F < kNumFlags; F++) {
154    const char *Name = FlagDescriptions[F].Name;
155    const char *Str = FlagValue(Param, Name);
156    if (Str)  {
157      if (FlagDescriptions[F].IntFlag) {
158        int Val = MyStol(Str);
159        *FlagDescriptions[F].IntFlag = Val;
160        if (Flags.verbosity >= 2)
161          Printf("Flag: %s %d\n", Name, Val);
162        return true;
163      } else if (FlagDescriptions[F].UIntFlag) {
164        unsigned int Val = std::stoul(Str);
165        *FlagDescriptions[F].UIntFlag = Val;
166        if (Flags.verbosity >= 2)
167          Printf("Flag: %s %u\n", Name, Val);
168        return true;
169      } else if (FlagDescriptions[F].StrFlag) {
170        *FlagDescriptions[F].StrFlag = Str;
171        if (Flags.verbosity >= 2)
172          Printf("Flag: %s %s\n", Name, Str);
173        return true;
174      } else {  // Deprecated flag.
175        Printf("Flag: %s: deprecated, don't use\n", Name);
176        return true;
177      }
178    }
179  }
180  Printf("\n\nWARNING: unrecognized flag '%s'; "
181         "use -help=1 to list all flags\n\n", Param);
182  return true;
183}
184
185// We don't use any library to minimize dependencies.
186static void ParseFlags(const Vector<std::string> &Args,
187                       const ExternalFunctions *EF) {
188  for (size_t F = 0; F < kNumFlags; F++) {
189    if (FlagDescriptions[F].IntFlag)
190      *FlagDescriptions[F].IntFlag = FlagDescriptions[F].Default;
191    if (FlagDescriptions[F].UIntFlag)
192      *FlagDescriptions[F].UIntFlag =
193          static_cast<unsigned int>(FlagDescriptions[F].Default);
194    if (FlagDescriptions[F].StrFlag)
195      *FlagDescriptions[F].StrFlag = nullptr;
196  }
197
198  // Disable len_control by default, if LLVMFuzzerCustomMutator is used.
199  if (EF->LLVMFuzzerCustomMutator) {
200    Flags.len_control = 0;
201    Printf("INFO: found LLVMFuzzerCustomMutator (%p). "
202           "Disabling -len_control by default.\n", EF->LLVMFuzzerCustomMutator);
203  }
204
205  Inputs = new Vector<std::string>;
206  for (size_t A = 1; A < Args.size(); A++) {
207    if (ParseOneFlag(Args[A].c_str())) {
208      if (Flags.ignore_remaining_args)
209        break;
210      continue;
211    }
212    Inputs->push_back(Args[A]);
213  }
214}
215
216static std::mutex Mu;
217
218static void PulseThread() {
219  while (true) {
220    SleepSeconds(600);
221    std::lock_guard<std::mutex> Lock(Mu);
222    Printf("pulse...\n");
223  }
224}
225
226static void WorkerThread(const Command &BaseCmd, std::atomic<unsigned> *Counter,
227                         unsigned NumJobs, std::atomic<bool> *HasErrors) {
228  while (true) {
229    unsigned C = (*Counter)++;
230    if (C >= NumJobs) break;
231    std::string Log = "fuzz-" + std::to_string(C) + ".log";
232    Command Cmd(BaseCmd);
233    Cmd.setOutputFile(Log);
234    Cmd.combineOutAndErr();
235    if (Flags.verbosity) {
236      std::string CommandLine = Cmd.toString();
237      Printf("%s\n", CommandLine.c_str());
238    }
239    int ExitCode = ExecuteCommand(Cmd);
240    if (ExitCode != 0)
241      *HasErrors = true;
242    std::lock_guard<std::mutex> Lock(Mu);
243    Printf("================== Job %u exited with exit code %d ============\n",
244           C, ExitCode);
245    fuzzer::CopyFileToErr(Log);
246  }
247}
248
249std::string CloneArgsWithoutX(const Vector<std::string> &Args,
250                              const char *X1, const char *X2) {
251  std::string Cmd;
252  for (auto &S : Args) {
253    if (FlagValue(S.c_str(), X1) || FlagValue(S.c_str(), X2))
254      continue;
255    Cmd += S + " ";
256  }
257  return Cmd;
258}
259
260static int RunInMultipleProcesses(const Vector<std::string> &Args,
261                                  unsigned NumWorkers, unsigned NumJobs) {
262  std::atomic<unsigned> Counter(0);
263  std::atomic<bool> HasErrors(false);
264  Command Cmd(Args);
265  Cmd.removeFlag("jobs");
266  Cmd.removeFlag("workers");
267  Vector<std::thread> V;
268  std::thread Pulse(PulseThread);
269  Pulse.detach();
270  for (unsigned i = 0; i < NumWorkers; i++)
271    V.push_back(std::thread(WorkerThread, std::ref(Cmd), &Counter, NumJobs, &HasErrors));
272  for (auto &T : V)
273    T.join();
274  return HasErrors ? 1 : 0;
275}
276
277static void RssThread(Fuzzer *F, size_t RssLimitMb) {
278  while (true) {
279    SleepSeconds(1);
280    size_t Peak = GetPeakRSSMb();
281    if (Peak > RssLimitMb)
282      F->RssLimitCallback();
283  }
284}
285
286static void StartRssThread(Fuzzer *F, size_t RssLimitMb) {
287  if (!RssLimitMb)
288    return;
289  std::thread T(RssThread, F, RssLimitMb);
290  T.detach();
291}
292
293int RunOneTest(Fuzzer *F, const char *InputFilePath, size_t MaxLen) {
294  Unit U = FileToVector(InputFilePath);
295  if (MaxLen && MaxLen < U.size())
296    U.resize(MaxLen);
297  F->ExecuteCallback(U.data(), U.size());
298  F->TryDetectingAMemoryLeak(U.data(), U.size(), true);
299  return 0;
300}
301
302static bool AllInputsAreFiles() {
303  if (Inputs->empty()) return false;
304  for (auto &Path : *Inputs)
305    if (!IsFile(Path))
306      return false;
307  return true;
308}
309
310static std::string GetDedupTokenFromCmdOutput(const std::string &S) {
311  auto Beg = S.find("DEDUP_TOKEN:");
312  if (Beg == std::string::npos)
313    return "";
314  auto End = S.find('\n', Beg);
315  if (End == std::string::npos)
316    return "";
317  return S.substr(Beg, End - Beg);
318}
319
320int CleanseCrashInput(const Vector<std::string> &Args,
321                       const FuzzingOptions &Options) {
322  if (Inputs->size() != 1 || !Flags.exact_artifact_path) {
323    Printf("ERROR: -cleanse_crash should be given one input file and"
324          " -exact_artifact_path\n");
325    exit(1);
326  }
327  std::string InputFilePath = Inputs->at(0);
328  std::string OutputFilePath = Flags.exact_artifact_path;
329  Command Cmd(Args);
330  Cmd.removeFlag("cleanse_crash");
331
332  assert(Cmd.hasArgument(InputFilePath));
333  Cmd.removeArgument(InputFilePath);
334
335  auto TmpFilePath = TempPath("CleanseCrashInput", ".repro");
336  Cmd.addArgument(TmpFilePath);
337  Cmd.setOutputFile(getDevNull());
338  Cmd.combineOutAndErr();
339
340  std::string CurrentFilePath = InputFilePath;
341  auto U = FileToVector(CurrentFilePath);
342  size_t Size = U.size();
343
344  const Vector<uint8_t> ReplacementBytes = {' ', 0xff};
345  for (int NumAttempts = 0; NumAttempts < 5; NumAttempts++) {
346    bool Changed = false;
347    for (size_t Idx = 0; Idx < Size; Idx++) {
348      Printf("CLEANSE[%d]: Trying to replace byte %zd of %zd\n", NumAttempts,
349             Idx, Size);
350      uint8_t OriginalByte = U[Idx];
351      if (ReplacementBytes.end() != std::find(ReplacementBytes.begin(),
352                                              ReplacementBytes.end(),
353                                              OriginalByte))
354        continue;
355      for (auto NewByte : ReplacementBytes) {
356        U[Idx] = NewByte;
357        WriteToFile(U, TmpFilePath);
358        auto ExitCode = ExecuteCommand(Cmd);
359        RemoveFile(TmpFilePath);
360        if (!ExitCode) {
361          U[Idx] = OriginalByte;
362        } else {
363          Changed = true;
364          Printf("CLEANSE: Replaced byte %zd with 0x%x\n", Idx, NewByte);
365          WriteToFile(U, OutputFilePath);
366          break;
367        }
368      }
369    }
370    if (!Changed) break;
371  }
372  return 0;
373}
374
375int MinimizeCrashInput(const Vector<std::string> &Args,
376                       const FuzzingOptions &Options) {
377  if (Inputs->size() != 1) {
378    Printf("ERROR: -minimize_crash should be given one input file\n");
379    exit(1);
380  }
381  std::string InputFilePath = Inputs->at(0);
382  Command BaseCmd(Args);
383  BaseCmd.removeFlag("minimize_crash");
384  BaseCmd.removeFlag("exact_artifact_path");
385  assert(BaseCmd.hasArgument(InputFilePath));
386  BaseCmd.removeArgument(InputFilePath);
387  if (Flags.runs <= 0 && Flags.max_total_time == 0) {
388    Printf("INFO: you need to specify -runs=N or "
389           "-max_total_time=N with -minimize_crash=1\n"
390           "INFO: defaulting to -max_total_time=600\n");
391    BaseCmd.addFlag("max_total_time", "600");
392  }
393
394  BaseCmd.combineOutAndErr();
395
396  std::string CurrentFilePath = InputFilePath;
397  while (true) {
398    Unit U = FileToVector(CurrentFilePath);
399    Printf("CRASH_MIN: minimizing crash input: '%s' (%zd bytes)\n",
400           CurrentFilePath.c_str(), U.size());
401
402    Command Cmd(BaseCmd);
403    Cmd.addArgument(CurrentFilePath);
404
405    Printf("CRASH_MIN: executing: %s\n", Cmd.toString().c_str());
406    std::string CmdOutput;
407    bool Success = ExecuteCommand(Cmd, &CmdOutput);
408    if (Success) {
409      Printf("ERROR: the input %s did not crash\n", CurrentFilePath.c_str());
410      exit(1);
411    }
412    Printf("CRASH_MIN: '%s' (%zd bytes) caused a crash. Will try to minimize "
413           "it further\n",
414           CurrentFilePath.c_str(), U.size());
415    auto DedupToken1 = GetDedupTokenFromCmdOutput(CmdOutput);
416    if (!DedupToken1.empty())
417      Printf("CRASH_MIN: DedupToken1: %s\n", DedupToken1.c_str());
418
419    std::string ArtifactPath =
420        Flags.exact_artifact_path
421            ? Flags.exact_artifact_path
422            : Options.ArtifactPrefix + "minimized-from-" + Hash(U);
423    Cmd.addFlag("minimize_crash_internal_step", "1");
424    Cmd.addFlag("exact_artifact_path", ArtifactPath);
425    Printf("CRASH_MIN: executing: %s\n", Cmd.toString().c_str());
426    CmdOutput.clear();
427    Success = ExecuteCommand(Cmd, &CmdOutput);
428    Printf("%s", CmdOutput.c_str());
429    if (Success) {
430      if (Flags.exact_artifact_path) {
431        CurrentFilePath = Flags.exact_artifact_path;
432        WriteToFile(U, CurrentFilePath);
433      }
434      Printf("CRASH_MIN: failed to minimize beyond %s (%d bytes), exiting\n",
435             CurrentFilePath.c_str(), U.size());
436      break;
437    }
438    auto DedupToken2 = GetDedupTokenFromCmdOutput(CmdOutput);
439    if (!DedupToken2.empty())
440      Printf("CRASH_MIN: DedupToken2: %s\n", DedupToken2.c_str());
441
442    if (DedupToken1 != DedupToken2) {
443      if (Flags.exact_artifact_path) {
444        CurrentFilePath = Flags.exact_artifact_path;
445        WriteToFile(U, CurrentFilePath);
446      }
447      Printf("CRASH_MIN: mismatch in dedup tokens"
448             " (looks like a different bug). Won't minimize further\n");
449      break;
450    }
451
452    CurrentFilePath = ArtifactPath;
453    Printf("*********************************\n");
454  }
455  return 0;
456}
457
458int MinimizeCrashInputInternalStep(Fuzzer *F, InputCorpus *Corpus) {
459  assert(Inputs->size() == 1);
460  std::string InputFilePath = Inputs->at(0);
461  Unit U = FileToVector(InputFilePath);
462  Printf("INFO: Starting MinimizeCrashInputInternalStep: %zd\n", U.size());
463  if (U.size() < 2) {
464    Printf("INFO: The input is small enough, exiting\n");
465    exit(0);
466  }
467  F->SetMaxInputLen(U.size());
468  F->SetMaxMutationLen(U.size() - 1);
469  F->MinimizeCrashLoop(U);
470  Printf("INFO: Done MinimizeCrashInputInternalStep, no crashes found\n");
471  exit(0);
472  return 0;
473}
474
475void Merge(Fuzzer *F, FuzzingOptions &Options, const Vector<std::string> &Args,
476           const Vector<std::string> &Corpora, const char *CFPathOrNull) {
477  if (Corpora.size() < 2) {
478    Printf("INFO: Merge requires two or more corpus dirs\n");
479    exit(0);
480  }
481
482  Vector<SizedFile> OldCorpus, NewCorpus;
483  GetSizedFilesFromDir(Corpora[0], &OldCorpus);
484  for (size_t i = 1; i < Corpora.size(); i++)
485    GetSizedFilesFromDir(Corpora[i], &NewCorpus);
486  std::sort(OldCorpus.begin(), OldCorpus.end());
487  std::sort(NewCorpus.begin(), NewCorpus.end());
488
489  std::string CFPath = CFPathOrNull ? CFPathOrNull : TempPath("Merge", ".txt");
490  Vector<std::string> NewFiles;
491  Set<uint32_t> NewFeatures, NewCov;
492  CrashResistantMerge(Args, OldCorpus, NewCorpus, &NewFiles, {}, &NewFeatures,
493                      {}, &NewCov, CFPath, true);
494  for (auto &Path : NewFiles)
495    F->WriteToOutputCorpus(FileToVector(Path, Options.MaxLen));
496  // We are done, delete the control file if it was a temporary one.
497  if (!Flags.merge_control_file)
498    RemoveFile(CFPath);
499
500  exit(0);
501}
502
503int AnalyzeDictionary(Fuzzer *F, const Vector<Unit>& Dict,
504                      UnitVector& Corpus) {
505  Printf("Started dictionary minimization (up to %d tests)\n",
506         Dict.size() * Corpus.size() * 2);
507
508  // Scores and usage count for each dictionary unit.
509  Vector<int> Scores(Dict.size());
510  Vector<int> Usages(Dict.size());
511
512  Vector<size_t> InitialFeatures;
513  Vector<size_t> ModifiedFeatures;
514  for (auto &C : Corpus) {
515    // Get coverage for the testcase without modifications.
516    F->ExecuteCallback(C.data(), C.size());
517    InitialFeatures.clear();
518    TPC.CollectFeatures([&](size_t Feature) {
519      InitialFeatures.push_back(Feature);
520    });
521
522    for (size_t i = 0; i < Dict.size(); ++i) {
523      Vector<uint8_t> Data = C;
524      auto StartPos = std::search(Data.begin(), Data.end(),
525                                  Dict[i].begin(), Dict[i].end());
526      // Skip dictionary unit, if the testcase does not contain it.
527      if (StartPos == Data.end())
528        continue;
529
530      ++Usages[i];
531      while (StartPos != Data.end()) {
532        // Replace all occurrences of dictionary unit in the testcase.
533        auto EndPos = StartPos + Dict[i].size();
534        for (auto It = StartPos; It != EndPos; ++It)
535          *It ^= 0xFF;
536
537        StartPos = std::search(EndPos, Data.end(),
538                               Dict[i].begin(), Dict[i].end());
539      }
540
541      // Get coverage for testcase with masked occurrences of dictionary unit.
542      F->ExecuteCallback(Data.data(), Data.size());
543      ModifiedFeatures.clear();
544      TPC.CollectFeatures([&](size_t Feature) {
545        ModifiedFeatures.push_back(Feature);
546      });
547
548      if (InitialFeatures == ModifiedFeatures)
549        --Scores[i];
550      else
551        Scores[i] += 2;
552    }
553  }
554
555  Printf("###### Useless dictionary elements. ######\n");
556  for (size_t i = 0; i < Dict.size(); ++i) {
557    // Dictionary units with positive score are treated as useful ones.
558    if (Scores[i] > 0)
559       continue;
560
561    Printf("\"");
562    PrintASCII(Dict[i].data(), Dict[i].size(), "\"");
563    Printf(" # Score: %d, Used: %d\n", Scores[i], Usages[i]);
564  }
565  Printf("###### End of useless dictionary elements. ######\n");
566  return 0;
567}
568
569Vector<std::string> ParseSeedInuts(const char *seed_inputs) {
570  // Parse -seed_inputs=file1,file2,... or -seed_inputs=@seed_inputs_file
571  Vector<std::string> Files;
572  if (!seed_inputs) return Files;
573  std::string SeedInputs;
574  if (Flags.seed_inputs[0] == '@')
575    SeedInputs = FileToString(Flags.seed_inputs + 1); // File contains list.
576  else
577    SeedInputs = Flags.seed_inputs; // seed_inputs contains the list.
578  if (SeedInputs.empty()) {
579    Printf("seed_inputs is empty or @file does not exist.\n");
580    exit(1);
581  }
582  // Parse SeedInputs.
583  size_t comma_pos = 0;
584  while ((comma_pos = SeedInputs.find_last_of(',')) != std::string::npos) {
585    Files.push_back(SeedInputs.substr(comma_pos + 1));
586    SeedInputs = SeedInputs.substr(0, comma_pos);
587  }
588  Files.push_back(SeedInputs);
589  return Files;
590}
591
592static Vector<SizedFile> ReadCorpora(const Vector<std::string> &CorpusDirs,
593    const Vector<std::string> &ExtraSeedFiles) {
594  Vector<SizedFile> SizedFiles;
595  size_t LastNumFiles = 0;
596  for (auto &Dir : CorpusDirs) {
597    GetSizedFilesFromDir(Dir, &SizedFiles);
598    Printf("INFO: % 8zd files found in %s\n", SizedFiles.size() - LastNumFiles,
599           Dir.c_str());
600    LastNumFiles = SizedFiles.size();
601  }
602  for (auto &File : ExtraSeedFiles)
603    if (auto Size = FileSize(File))
604      SizedFiles.push_back({File, Size});
605  return SizedFiles;
606}
607
608int FuzzerDriver(int *argc, char ***argv, UserCallback Callback) {
609  using namespace fuzzer;
610  assert(argc && argv && "Argument pointers cannot be nullptr");
611  std::string Argv0((*argv)[0]);
612  EF = new ExternalFunctions();
613  if (EF->LLVMFuzzerInitialize)
614    EF->LLVMFuzzerInitialize(argc, argv);
615  if (EF->__msan_scoped_disable_interceptor_checks)
616    EF->__msan_scoped_disable_interceptor_checks();
617  const Vector<std::string> Args(*argv, *argv + *argc);
618  assert(!Args.empty());
619  ProgName = new std::string(Args[0]);
620  if (Argv0 != *ProgName) {
621    Printf("ERROR: argv[0] has been modified in LLVMFuzzerInitialize\n");
622    exit(1);
623  }
624  ParseFlags(Args, EF);
625  if (Flags.help) {
626    PrintHelp();
627    return 0;
628  }
629
630  if (Flags.close_fd_mask & 2)
631    DupAndCloseStderr();
632  if (Flags.close_fd_mask & 1)
633    CloseStdout();
634
635  if (Flags.jobs > 0 && Flags.workers == 0) {
636    Flags.workers = std::min(NumberOfCpuCores() / 2, Flags.jobs);
637    if (Flags.workers > 1)
638      Printf("Running %u workers\n", Flags.workers);
639  }
640
641  if (Flags.workers > 0 && Flags.jobs > 0)
642    return RunInMultipleProcesses(Args, Flags.workers, Flags.jobs);
643
644  FuzzingOptions Options;
645  Options.Verbosity = Flags.verbosity;
646  Options.MaxLen = Flags.max_len;
647  Options.LenControl = Flags.len_control;
648  Options.UnitTimeoutSec = Flags.timeout;
649  Options.ErrorExitCode = Flags.error_exitcode;
650  Options.TimeoutExitCode = Flags.timeout_exitcode;
651  Options.IgnoreTimeouts = Flags.ignore_timeouts;
652  Options.IgnoreOOMs = Flags.ignore_ooms;
653  Options.IgnoreCrashes = Flags.ignore_crashes;
654  Options.MaxTotalTimeSec = Flags.max_total_time;
655  Options.DoCrossOver = Flags.cross_over;
656  Options.MutateDepth = Flags.mutate_depth;
657  Options.ReduceDepth = Flags.reduce_depth;
658  Options.UseCounters = Flags.use_counters;
659  Options.UseMemmem = Flags.use_memmem;
660  Options.UseCmp = Flags.use_cmp;
661  Options.UseValueProfile = Flags.use_value_profile;
662  Options.Shrink = Flags.shrink;
663  Options.ReduceInputs = Flags.reduce_inputs;
664  Options.ShuffleAtStartUp = Flags.shuffle;
665  Options.PreferSmall = Flags.prefer_small;
666  Options.ReloadIntervalSec = Flags.reload;
667  Options.OnlyASCII = Flags.only_ascii;
668  Options.DetectLeaks = Flags.detect_leaks;
669  Options.PurgeAllocatorIntervalSec = Flags.purge_allocator_interval;
670  Options.TraceMalloc = Flags.trace_malloc;
671  Options.RssLimitMb = Flags.rss_limit_mb;
672  Options.MallocLimitMb = Flags.malloc_limit_mb;
673  if (!Options.MallocLimitMb)
674    Options.MallocLimitMb = Options.RssLimitMb;
675  if (Flags.runs >= 0)
676    Options.MaxNumberOfRuns = Flags.runs;
677  if (!Inputs->empty() && !Flags.minimize_crash_internal_step)
678    Options.OutputCorpus = (*Inputs)[0];
679  Options.ReportSlowUnits = Flags.report_slow_units;
680  if (Flags.artifact_prefix)
681    Options.ArtifactPrefix = Flags.artifact_prefix;
682  if (Flags.exact_artifact_path)
683    Options.ExactArtifactPath = Flags.exact_artifact_path;
684  Vector<Unit> Dictionary;
685  if (Flags.dict)
686    if (!ParseDictionaryFile(FileToString(Flags.dict), &Dictionary))
687      return 1;
688  if (Flags.verbosity > 0 && !Dictionary.empty())
689    Printf("Dictionary: %zd entries\n", Dictionary.size());
690  bool RunIndividualFiles = AllInputsAreFiles();
691  Options.SaveArtifacts =
692      !RunIndividualFiles || Flags.minimize_crash_internal_step;
693  Options.PrintNewCovPcs = Flags.print_pcs;
694  Options.PrintNewCovFuncs = Flags.print_funcs;
695  Options.PrintFinalStats = Flags.print_final_stats;
696  Options.PrintCorpusStats = Flags.print_corpus_stats;
697  Options.PrintCoverage = Flags.print_coverage;
698  if (Flags.exit_on_src_pos)
699    Options.ExitOnSrcPos = Flags.exit_on_src_pos;
700  if (Flags.exit_on_item)
701    Options.ExitOnItem = Flags.exit_on_item;
702  if (Flags.focus_function)
703    Options.FocusFunction = Flags.focus_function;
704  if (Flags.data_flow_trace)
705    Options.DataFlowTrace = Flags.data_flow_trace;
706  if (Flags.features_dir)
707    Options.FeaturesDir = Flags.features_dir;
708  if (Flags.collect_data_flow)
709    Options.CollectDataFlow = Flags.collect_data_flow;
710  if (Flags.stop_file)
711    Options.StopFile = Flags.stop_file;
712  Options.Entropic = Flags.entropic;
713  Options.EntropicFeatureFrequencyThreshold =
714      (size_t)Flags.entropic_feature_frequency_threshold;
715  Options.EntropicNumberOfRarestFeatures =
716      (size_t)Flags.entropic_number_of_rarest_features;
717  if (Options.Entropic) {
718    if (!Options.FocusFunction.empty()) {
719      Printf("ERROR: The parameters `--entropic` and `--focus_function` cannot "
720             "be used together.\n");
721      exit(1);
722    }
723    Printf("INFO: Running with entropic power schedule (0x%X, %d).\n",
724           Options.EntropicFeatureFrequencyThreshold,
725           Options.EntropicNumberOfRarestFeatures);
726  }
727  struct EntropicOptions Entropic;
728  Entropic.Enabled = Options.Entropic;
729  Entropic.FeatureFrequencyThreshold =
730      Options.EntropicFeatureFrequencyThreshold;
731  Entropic.NumberOfRarestFeatures = Options.EntropicNumberOfRarestFeatures;
732
733  unsigned Seed = Flags.seed;
734  // Initialize Seed.
735  if (Seed == 0)
736    Seed =
737        std::chrono::system_clock::now().time_since_epoch().count() + GetPid();
738  if (Flags.verbosity)
739    Printf("INFO: Seed: %u\n", Seed);
740
741  if (Flags.collect_data_flow && !Flags.fork && !Flags.merge) {
742    if (RunIndividualFiles)
743      return CollectDataFlow(Flags.collect_data_flow, Flags.data_flow_trace,
744                        ReadCorpora({}, *Inputs));
745    else
746      return CollectDataFlow(Flags.collect_data_flow, Flags.data_flow_trace,
747                        ReadCorpora(*Inputs, {}));
748  }
749
750  Random Rand(Seed);
751  auto *MD = new MutationDispatcher(Rand, Options);
752  auto *Corpus = new InputCorpus(Options.OutputCorpus, Entropic);
753  auto *F = new Fuzzer(Callback, *Corpus, *MD, Options);
754
755  for (auto &U: Dictionary)
756    if (U.size() <= Word::GetMaxSize())
757      MD->AddWordToManualDictionary(Word(U.data(), U.size()));
758
759      // Threads are only supported by Chrome. Don't use them with emscripten
760      // for now.
761#if !LIBFUZZER_EMSCRIPTEN
762  StartRssThread(F, Flags.rss_limit_mb);
763#endif // LIBFUZZER_EMSCRIPTEN
764
765  Options.HandleAbrt = Flags.handle_abrt;
766  Options.HandleBus = Flags.handle_bus;
767  Options.HandleFpe = Flags.handle_fpe;
768  Options.HandleIll = Flags.handle_ill;
769  Options.HandleInt = Flags.handle_int;
770  Options.HandleSegv = Flags.handle_segv;
771  Options.HandleTerm = Flags.handle_term;
772  Options.HandleXfsz = Flags.handle_xfsz;
773  Options.HandleUsr1 = Flags.handle_usr1;
774  Options.HandleUsr2 = Flags.handle_usr2;
775  SetSignalHandler(Options);
776
777  std::atexit(Fuzzer::StaticExitCallback);
778
779  if (Flags.minimize_crash)
780    return MinimizeCrashInput(Args, Options);
781
782  if (Flags.minimize_crash_internal_step)
783    return MinimizeCrashInputInternalStep(F, Corpus);
784
785  if (Flags.cleanse_crash)
786    return CleanseCrashInput(Args, Options);
787
788  if (RunIndividualFiles) {
789    Options.SaveArtifacts = false;
790    int Runs = std::max(1, Flags.runs);
791    Printf("%s: Running %zd inputs %d time(s) each.\n", ProgName->c_str(),
792           Inputs->size(), Runs);
793    for (auto &Path : *Inputs) {
794      auto StartTime = system_clock::now();
795      Printf("Running: %s\n", Path.c_str());
796      for (int Iter = 0; Iter < Runs; Iter++)
797        RunOneTest(F, Path.c_str(), Options.MaxLen);
798      auto StopTime = system_clock::now();
799      auto MS = duration_cast<milliseconds>(StopTime - StartTime).count();
800      Printf("Executed %s in %zd ms\n", Path.c_str(), (long)MS);
801    }
802    Printf("***\n"
803           "*** NOTE: fuzzing was not performed, you have only\n"
804           "***       executed the target code on a fixed set of inputs.\n"
805           "***\n");
806    F->PrintFinalStats();
807    exit(0);
808  }
809
810  if (Flags.fork)
811    FuzzWithFork(F->GetMD().GetRand(), Options, Args, *Inputs, Flags.fork);
812
813  if (Flags.merge)
814    Merge(F, Options, Args, *Inputs, Flags.merge_control_file);
815
816  if (Flags.merge_inner) {
817    const size_t kDefaultMaxMergeLen = 1 << 20;
818    if (Options.MaxLen == 0)
819      F->SetMaxInputLen(kDefaultMaxMergeLen);
820    assert(Flags.merge_control_file);
821    F->CrashResistantMergeInternalStep(Flags.merge_control_file);
822    exit(0);
823  }
824
825  if (Flags.analyze_dict) {
826    size_t MaxLen = INT_MAX;  // Large max length.
827    UnitVector InitialCorpus;
828    for (auto &Inp : *Inputs) {
829      Printf("Loading corpus dir: %s\n", Inp.c_str());
830      ReadDirToVectorOfUnits(Inp.c_str(), &InitialCorpus, nullptr,
831                             MaxLen, /*ExitOnError=*/false);
832    }
833
834    if (Dictionary.empty() || Inputs->empty()) {
835      Printf("ERROR: can't analyze dict without dict and corpus provided\n");
836      return 1;
837    }
838    if (AnalyzeDictionary(F, Dictionary, InitialCorpus)) {
839      Printf("Dictionary analysis failed\n");
840      exit(1);
841    }
842    Printf("Dictionary analysis succeeded\n");
843    exit(0);
844  }
845
846  auto CorporaFiles = ReadCorpora(*Inputs, ParseSeedInuts(Flags.seed_inputs));
847  F->Loop(CorporaFiles);
848
849  if (Flags.verbosity)
850    Printf("Done %zd runs in %zd second(s)\n", F->getTotalNumberOfRuns(),
851           F->secondsSinceProcessStartUp());
852  F->PrintFinalStats();
853
854  exit(0);  // Don't let F destroy itself.
855}
856
857// Storage for global ExternalFunctions object.
858ExternalFunctions *EF = nullptr;
859
860}  // namespace fuzzer
861