compiler-rt/lib/fuzzer/FuzzerDriver.cpp

   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
  35 extern "C" void __libfuzzer_is_present() {}
  36 #if defined(_M_IX86) || defined(__i386__)
  37 #pragma comment(linker, "/include:___libfuzzer_is_present")
  38 #else
  39 #pragma comment(linker, "/include:__libfuzzer_is_present")
  40 #endif
  41 #else
  42 extern "C" __attribute__((used)) void __libfuzzer_is_present() {}
  43 #endif  // LIBFUZZER_MSVC
  44
  45 namespace fuzzer {
  46
  47 // Program arguments.
  48 struct FlagDescription {
  49   const char *Name;
  50   const char *Description;
  51   int   Default;
  52   int   *IntFlag;
  53   const char **StrFlag;
  54   unsigned int *UIntFlag;
  55 };
  56
  57 struct {
  58 #define FUZZER_DEPRECATED_FLAG(Name)
  59 #define FUZZER_FLAG_INT(Name, Default, Description) int Name;
  60 #define FUZZER_FLAG_UNSIGNED(Name, Default, Description) unsigned int Name;
  61 #define FUZZER_FLAG_STRING(Name, Description) const char *Name;
  62 #include "FuzzerFlags.def"
  63 #undef FUZZER_DEPRECATED_FLAG
  64 #undef FUZZER_FLAG_INT
  65 #undef FUZZER_FLAG_UNSIGNED
  66 #undef FUZZER_FLAG_STRING
  67 } Flags;
  68
  69 static const FlagDescription FlagDescriptions [] {
  70 #define FUZZER_DEPRECATED_FLAG(Name)                                           \
  71   {#Name, "Deprecated; don't use", 0, nullptr, nullptr, nullptr},
  72 #define FUZZER_FLAG_INT(Name, Default, Description)                            \
  73   {#Name, Description, Default, &Flags.Name, nullptr, nullptr},
  74 #define FUZZER_FLAG_UNSIGNED(Name, Default, Description)                       \
  75   {#Name,   Description, static_cast<int>(Default),                            \
  76    nullptr, nullptr, &Flags.Name},
  77 #define FUZZER_FLAG_STRING(Name, Description)                                  \
  78   {#Name, Description, 0, nullptr, &Flags.Name, nullptr},
  79 #include "FuzzerFlags.def"
  80 #undef FUZZER_DEPRECATED_FLAG
  81 #undef FUZZER_FLAG_INT
  82 #undef FUZZER_FLAG_UNSIGNED
  83 #undef FUZZER_FLAG_STRING
  84 };
  85
  86 static const size_t kNumFlags =
  87     sizeof(FlagDescriptions) / sizeof(FlagDescriptions[0]);
  88
  89 static std::vector<std::string> *Inputs;
  90 static std::string *ProgName;
  91
  92 static void PrintHelp() {
  93   Printf("Usage:\n");
  94   auto Prog = ProgName->c_str();
  95   Printf("\nTo run fuzzing pass 0 or more directories.\n");
  96   Printf("%s [-flag1=val1 [-flag2=val2 ...] ] [dir1 [dir2 ...] ]\n", Prog);
  97
  98   Printf("\nTo run individual tests without fuzzing pass 1 or more files:\n");
  99   Printf("%s [-flag1=val1 [-flag2=val2 ...] ] file1 [file2 ...]\n", Prog);
 100
 101   Printf("\nFlags: (strictly in form -flag=value)\n");
 102   size_t MaxFlagLen = 0;
 103   for (size_t F = 0; F < kNumFlags; F++)
 104     MaxFlagLen = std::max(strlen(FlagDescriptions[F].Name), MaxFlagLen);
 105
 106   for (size_t F = 0; F < kNumFlags; F++) {
 107     const auto &D = FlagDescriptions[F];
 108     if (strstr(D.Description, "internal flag") == D.Description) continue;
 109     Printf(" %s", D.Name);
 110     for (size_t i = 0, n = MaxFlagLen - strlen(D.Name); i < n; i++)
 111       Printf(" ");
 112     Printf("\t");
 113     Printf("%d\t%s\n", D.Default, D.Description);
 114   }
 115   Printf("\nFlags starting with '--' will be ignored and "
 116             "will be passed verbatim to subprocesses.\n");
 117 }
 118
 119 static const char *FlagValue(const char *Param, const char *Name) {
 120   size_t Len = strlen(Name);
 121   if (Param[0] == '-' && strstr(Param + 1, Name) == Param + 1 &&
 122       Param[Len + 1] == '=')
 123       return &Param[Len + 2];
 124   return nullptr;
 125 }
 126
 127 // Avoid calling stol as it triggers a bug in clang/glibc build.
 128 static long MyStol(const char *Str) {
 129   long Res = 0;
 130   long Sign = 1;
 131   if (*Str == '-') {
 132     Str++;
 133     Sign = -1;
 134   }
 135   for (size_t i = 0; Str[i]; i++) {
 136     char Ch = Str[i];
 137     if (Ch < '0' || Ch > '9')
 138       return Res;
 139     Res = Res * 10 + (Ch - '0');
 140   }
 141   return Res * Sign;
 142 }
 143
 144 static bool ParseOneFlag(const char *Param) {
 145   if (Param[0] != '-') return false;
 146   if (Param[1] == '-') {
 147     static bool PrintedWarning = false;
 148     if (!PrintedWarning) {
 149       PrintedWarning = true;
 150       Printf("INFO: libFuzzer ignores flags that start with '--'\n");
 151     }
 152     for (size_t F = 0; F < kNumFlags; F++)
 153       if (FlagValue(Param + 1, FlagDescriptions[F].Name))
 154         Printf("WARNING: did you mean '%s' (single dash)?\n", Param + 1);
 155     return true;
 156   }
 157   for (size_t F = 0; F < kNumFlags; F++) {
 158     const char *Name = FlagDescriptions[F].Name;
 159     const char *Str = FlagValue(Param, Name);
 160     if (Str)  {
 161       if (FlagDescriptions[F].IntFlag) {
 162         auto Val = MyStol(Str);
 163         *FlagDescriptions[F].IntFlag = static_cast<int>(Val);
 164         if (Flags.verbosity >= 2)
 165           Printf("Flag: %s %d\n", Name, Val);
 166         return true;
 167       } else if (FlagDescriptions[F].UIntFlag) {
 168         auto Val = std::stoul(Str);
 169         *FlagDescriptions[F].UIntFlag = static_cast<unsigned int>(Val);
 170         if (Flags.verbosity >= 2)
 171           Printf("Flag: %s %u\n", Name, Val);
 172         return true;
 173       } else if (FlagDescriptions[F].StrFlag) {
 174         *FlagDescriptions[F].StrFlag = Str;
 175         if (Flags.verbosity >= 2)
 176           Printf("Flag: %s %s\n", Name, Str);
 177         return true;
 178       } else {  // Deprecated flag.
 179         Printf("Flag: %s: deprecated, don't use\n", Name);
 180         return true;
 181       }
 182     }
 183   }
 184   Printf("\n\nWARNING: unrecognized flag '%s'; "
 185          "use -help=1 to list all flags\n\n", Param);
 186   return true;
 187 }
 188
 189 // We don't use any library to minimize dependencies.
 190 static void ParseFlags(const std::vector<std::string> &Args,
 191                        const ExternalFunctions *EF) {
 192   for (size_t F = 0; F < kNumFlags; F++) {
 193     if (FlagDescriptions[F].IntFlag)
 194       *FlagDescriptions[F].IntFlag = FlagDescriptions[F].Default;
 195     if (FlagDescriptions[F].UIntFlag)
 196       *FlagDescriptions[F].UIntFlag =
 197           static_cast<unsigned int>(FlagDescriptions[F].Default);
 198     if (FlagDescriptions[F].StrFlag)
 199       *FlagDescriptions[F].StrFlag = nullptr;
 200   }
 201
 202   // Disable len_control by default, if LLVMFuzzerCustomMutator is used.
 203   if (EF->LLVMFuzzerCustomMutator) {
 204     Flags.len_control = 0;
 205     Printf("INFO: found LLVMFuzzerCustomMutator (%p). "
 206            "Disabling -len_control by default.\n", EF->LLVMFuzzerCustomMutator);
 207   }
 208
 209   Inputs = new std::vector<std::string>;
 210   for (size_t A = 1; A < Args.size(); A++) {
 211     if (ParseOneFlag(Args[A].c_str())) {
 212       if (Flags.ignore_remaining_args)
 213         break;
 214       continue;
 215     }
 216     Inputs->push_back(Args[A]);
 217   }
 218 }
 219
 220 static std::mutex Mu;
 221
 222 static void PulseThread() {
 223   while (true) {
 224     SleepSeconds(600);
 225     std::lock_guard<std::mutex> Lock(Mu);
 226     Printf("pulse...\n");
 227   }
 228 }
 229
 230 static void WorkerThread(const Command &BaseCmd, std::atomic<unsigned> *Counter,
 231                          unsigned NumJobs, std::atomic<bool> *HasErrors) {
 232   ScopedDisableMsanInterceptorChecks S;
 233   while (true) {
 234     unsigned C = (*Counter)++;
 235     if (C >= NumJobs) break;
 236     std::string Log = "fuzz-" + std::to_string(C) + ".log";
 237     Command Cmd(BaseCmd);
 238     Cmd.setOutputFile(Log);
 239     Cmd.combineOutAndErr();
 240     if (Flags.verbosity) {
 241       std::string CommandLine = Cmd.toString();
 242       Printf("%s\n", CommandLine.c_str());
 243     }
 244     int ExitCode = ExecuteCommand(Cmd);
 245     if (ExitCode != 0)
 246       *HasErrors = true;
 247     std::lock_guard<std::mutex> Lock(Mu);
 248     Printf("================== Job %u exited with exit code %d ============\n",
 249            C, ExitCode);
 250     fuzzer::CopyFileToErr(Log);
 251   }
 252 }
 253
 254 static void ValidateDirectoryExists(const std::string &Path,
 255                                     bool CreateDirectory) {
 256   if (Path.empty()) {
 257     Printf("ERROR: Provided directory path is an empty string\n");
 258     exit(1);
 259   }
 260
 261   if (IsDirectory(Path))
 262     return;
 263
 264   if (CreateDirectory) {
 265     if (!MkDirRecursive(Path)) {
 266       Printf("ERROR: Failed to create directory \"%s\"\n", Path.c_str());
 267       exit(1);
 268     }
 269     return;
 270   }
 271
 272   Printf("ERROR: The required directory \"%s\" does not exist\n", Path.c_str());
 273   exit(1);
 274 }
 275
 276 std::string CloneArgsWithoutX(const std::vector<std::string> &Args,
 277                               const char *X1, const char *X2) {
 278   std::string Cmd;
 279   for (auto &S : Args) {
 280     if (FlagValue(S.c_str(), X1) || FlagValue(S.c_str(), X2))
 281       continue;
 282     Cmd += S + " ";
 283   }
 284   return Cmd;
 285 }
 286
 287 static int RunInMultipleProcesses(const std::vector<std::string> &Args,
 288                                   unsigned NumWorkers, unsigned NumJobs) {
 289   std::atomic<unsigned> Counter(0);
 290   std::atomic<bool> HasErrors(false);
 291   Command Cmd(Args);
 292   Cmd.removeFlag("jobs");
 293   Cmd.removeFlag("workers");
 294   std::vector<std::thread> V;
 295   std::thread Pulse(PulseThread);
 296   Pulse.detach();
 297   V.resize(NumWorkers);
 298   for (unsigned i = 0; i < NumWorkers; i++) {
 299     V[i] = std::thread(WorkerThread, std::ref(Cmd), &Counter, NumJobs,
 300                             &HasErrors);
 301     SetThreadName(V[i], "FuzzerWorker");
 302   }
 303   for (auto &T : V)
 304     T.join();
 305   return HasErrors ? 1 : 0;
 306 }
 307
 308 static void RssThread(Fuzzer *F, size_t RssLimitMb) {
 309   while (true) {
 310     SleepSeconds(1);
 311     size_t Peak = GetPeakRSSMb();
 312     if (Peak > RssLimitMb)
 313       F->RssLimitCallback();
 314   }
 315 }
 316
 317 static void StartRssThread(Fuzzer *F, size_t RssLimitMb) {
 318   if (!RssLimitMb)
 319     return;
 320   std::thread T(RssThread, F, RssLimitMb);
 321   T.detach();
 322 }
 323
 324 int RunOneTest(Fuzzer *F, const char *InputFilePath, size_t MaxLen) {
 325   Unit U = FileToVector(InputFilePath);
 326   if (MaxLen && MaxLen < U.size())
 327     U.resize(MaxLen);
 328   F->ExecuteCallback(U.data(), U.size());
 329   if (Flags.print_full_coverage) {
 330     // Leak detection is not needed when collecting full coverage data.
 331     F->TPCUpdateObservedPCs();
 332   } else {
 333     F->TryDetectingAMemoryLeak(U.data(), U.size(), true);
 334   }
 335   return 0;
 336 }
 337
 338 static bool AllInputsAreFiles() {
 339   if (Inputs->empty()) return false;
 340   for (auto &Path : *Inputs)
 341     if (!IsFile(Path))
 342       return false;
 343   return true;
 344 }
 345
 346 static std::string GetDedupTokenFromCmdOutput(const std::string &S) {
 347   auto Beg = S.find("DEDUP_TOKEN:");
 348   if (Beg == std::string::npos)
 349     return "";
 350   auto End = S.find('\n', Beg);
 351   if (End == std::string::npos)
 352     return "";
 353   return S.substr(Beg, End - Beg);
 354 }
 355
 356 int CleanseCrashInput(const std::vector<std::string> &Args,
 357                       const FuzzingOptions &Options) {
 358   if (Inputs->size() != 1 || !Flags.exact_artifact_path) {
 359     Printf("ERROR: -cleanse_crash should be given one input file and"
 360           " -exact_artifact_path\n");
 361     exit(1);
 362   }
 363   std::string InputFilePath = Inputs->at(0);
 364   std::string OutputFilePath = Flags.exact_artifact_path;
 365   Command Cmd(Args);
 366   Cmd.removeFlag("cleanse_crash");
 367
 368   assert(Cmd.hasArgument(InputFilePath));
 369   Cmd.removeArgument(InputFilePath);
 370
 371   auto TmpFilePath = TempPath("CleanseCrashInput", ".repro");
 372   Cmd.addArgument(TmpFilePath);
 373   Cmd.setOutputFile(getDevNull());
 374   Cmd.combineOutAndErr();
 375
 376   std::string CurrentFilePath = InputFilePath;
 377   auto U = FileToVector(CurrentFilePath);
 378   size_t Size = U.size();
 379
 380   const std::vector<uint8_t> ReplacementBytes = {' ', 0xff};
 381   for (int NumAttempts = 0; NumAttempts < 5; NumAttempts++) {
 382     bool Changed = false;
 383     for (size_t Idx = 0; Idx < Size; Idx++) {
 384       Printf("CLEANSE[%d]: Trying to replace byte %zd of %zd\n", NumAttempts,
 385              Idx, Size);
 386       uint8_t OriginalByte = U[Idx];
 387       if (ReplacementBytes.end() != std::find(ReplacementBytes.begin(),
 388                                               ReplacementBytes.end(),
 389                                               OriginalByte))
 390         continue;
 391       for (auto NewByte : ReplacementBytes) {
 392         U[Idx] = NewByte;
 393         WriteToFile(U, TmpFilePath);
 394         auto ExitCode = ExecuteCommand(Cmd);
 395         RemoveFile(TmpFilePath);
 396         if (!ExitCode) {
 397           U[Idx] = OriginalByte;
 398         } else {
 399           Changed = true;
 400           Printf("CLEANSE: Replaced byte %zd with 0x%x\n", Idx, NewByte);
 401           WriteToFile(U, OutputFilePath);
 402           break;
 403         }
 404       }
 405     }
 406     if (!Changed) break;
 407   }
 408   return 0;
 409 }
 410
 411 int MinimizeCrashInput(const std::vector<std::string> &Args,
 412                        const FuzzingOptions &Options) {
 413   if (Inputs->size() != 1) {
 414     Printf("ERROR: -minimize_crash should be given one input file\n");
 415     exit(1);
 416   }
 417   std::string InputFilePath = Inputs->at(0);
 418   Command BaseCmd(Args);
 419   BaseCmd.removeFlag("minimize_crash");
 420   BaseCmd.removeFlag("exact_artifact_path");
 421   assert(BaseCmd.hasArgument(InputFilePath));
 422   BaseCmd.removeArgument(InputFilePath);
 423   if (Flags.runs <= 0 && Flags.max_total_time == 0) {
 424     Printf("INFO: you need to specify -runs=N or "
 425            "-max_total_time=N with -minimize_crash=1\n"
 426            "INFO: defaulting to -max_total_time=600\n");
 427     BaseCmd.addFlag("max_total_time", "600");
 428   }
 429
 430   BaseCmd.combineOutAndErr();
 431
 432   std::string CurrentFilePath = InputFilePath;
 433   while (true) {
 434     Unit U = FileToVector(CurrentFilePath);
 435     Printf("CRASH_MIN: minimizing crash input: '%s' (%zd bytes)\n",
 436            CurrentFilePath.c_str(), U.size());
 437
 438     Command Cmd(BaseCmd);
 439     Cmd.addArgument(CurrentFilePath);
 440
 441     Printf("CRASH_MIN: executing: %s\n", Cmd.toString().c_str());
 442     std::string CmdOutput;
 443     bool Success = ExecuteCommand(Cmd, &CmdOutput);
 444     if (Success) {
 445       Printf("ERROR: the input %s did not crash\n", CurrentFilePath.c_str());
 446       exit(1);
 447     }
 448     Printf("CRASH_MIN: '%s' (%zd bytes) caused a crash. Will try to minimize "
 449            "it further\n",
 450            CurrentFilePath.c_str(), U.size());
 451     auto DedupToken1 = GetDedupTokenFromCmdOutput(CmdOutput);
 452     if (!DedupToken1.empty())
 453       Printf("CRASH_MIN: DedupToken1: %s\n", DedupToken1.c_str());
 454
 455     std::string ArtifactPath =
 456         Flags.exact_artifact_path
 457             ? Flags.exact_artifact_path
 458             : Options.ArtifactPrefix + "minimized-from-" + Hash(U);
 459     Cmd.addFlag("minimize_crash_internal_step", "1");
 460     Cmd.addFlag("exact_artifact_path", ArtifactPath);
 461     Printf("CRASH_MIN: executing: %s\n", Cmd.toString().c_str());
 462     CmdOutput.clear();
 463     Success = ExecuteCommand(Cmd, &CmdOutput);
 464     Printf("%s", CmdOutput.c_str());
 465     if (Success) {
 466       if (Flags.exact_artifact_path) {
 467         CurrentFilePath = Flags.exact_artifact_path;
 468         WriteToFile(U, CurrentFilePath);
 469       }
 470       Printf("CRASH_MIN: failed to minimize beyond %s (%zu bytes), exiting\n",
 471              CurrentFilePath.c_str(), U.size());
 472       break;
 473     }
 474     auto DedupToken2 = GetDedupTokenFromCmdOutput(CmdOutput);
 475     if (!DedupToken2.empty())
 476       Printf("CRASH_MIN: DedupToken2: %s\n", DedupToken2.c_str());
 477
 478     if (DedupToken1 != DedupToken2) {
 479       if (Flags.exact_artifact_path) {
 480         CurrentFilePath = Flags.exact_artifact_path;
 481         WriteToFile(U, CurrentFilePath);
 482       }
 483       Printf("CRASH_MIN: mismatch in dedup tokens"
 484              " (looks like a different bug). Won't minimize further\n");
 485       break;
 486     }
 487
 488     CurrentFilePath = ArtifactPath;
 489     Printf("*********************************\n");
 490   }
 491   return 0;
 492 }
 493
 494 int MinimizeCrashInputInternalStep(Fuzzer *F, InputCorpus *Corpus) {
 495   assert(Inputs->size() == 1);
 496   std::string InputFilePath = Inputs->at(0);
 497   Unit U = FileToVector(InputFilePath);
 498   Printf("INFO: Starting MinimizeCrashInputInternalStep: %zd\n", U.size());
 499   if (U.size() < 2) {
 500     Printf("INFO: The input is small enough, exiting\n");
 501     exit(0);
 502   }
 503   F->SetMaxInputLen(U.size());
 504   F->SetMaxMutationLen(U.size() - 1);
 505   F->MinimizeCrashLoop(U);
 506   Printf("INFO: Done MinimizeCrashInputInternalStep, no crashes found\n");
 507   exit(0);
 508 }
 509
 510 void Merge(Fuzzer *F, FuzzingOptions &Options,
 511            const std::vector<std::string> &Args,
 512            const std::vector<std::string> &Corpora, const char *CFPathOrNull) {
 513   if (Corpora.size() < 2) {
 514     Printf("INFO: Merge requires two or more corpus dirs\n");
 515     exit(0);
 516   }
 517
 518   std::vector<SizedFile> OldCorpus, NewCorpus;
 519   GetSizedFilesFromDir(Corpora[0], &OldCorpus);
 520   for (size_t i = 1; i < Corpora.size(); i++)
 521     GetSizedFilesFromDir(Corpora[i], &NewCorpus);
 522   std::sort(OldCorpus.begin(), OldCorpus.end());
 523   std::sort(NewCorpus.begin(), NewCorpus.end());
 524
 525   std::string CFPath = CFPathOrNull ? CFPathOrNull : TempPath("Merge", ".txt");
 526   std::vector<std::string> NewFiles;
 527   std::set<uint32_t> NewFeatures, NewCov;
 528   CrashResistantMerge(Args, OldCorpus, NewCorpus, &NewFiles, {}, &NewFeatures,
 529                       {}, &NewCov, CFPath, true, Flags.set_cover_merge);
 530   for (auto &Path : NewFiles)
 531     F->WriteToOutputCorpus(FileToVector(Path, Options.MaxLen));
 532   // We are done, delete the control file if it was a temporary one.
 533   if (!Flags.merge_control_file)
 534     RemoveFile(CFPath);
 535
 536   exit(0);
 537 }
 538
 539 int AnalyzeDictionary(Fuzzer *F, const std::vector<Unit> &Dict,
 540                       UnitVector &Corpus) {
 541   Printf("Started dictionary minimization (up to %zu tests)\n",
 542          Dict.size() * Corpus.size() * 2);
 543
 544   // Scores and usage count for each dictionary unit.
 545   std::vector<int> Scores(Dict.size());
 546   std::vector<int> Usages(Dict.size());
 547
 548   std::vector<size_t> InitialFeatures;
 549   std::vector<size_t> ModifiedFeatures;
 550   for (auto &C : Corpus) {
 551     // Get coverage for the testcase without modifications.
 552     F->ExecuteCallback(C.data(), C.size());
 553     InitialFeatures.clear();
 554     TPC.CollectFeatures([&](size_t Feature) {
 555       InitialFeatures.push_back(Feature);
 556     });
 557
 558     for (size_t i = 0; i < Dict.size(); ++i) {
 559       std::vector<uint8_t> Data = C;
 560       auto StartPos = std::search(Data.begin(), Data.end(),
 561                                   Dict[i].begin(), Dict[i].end());
 562       // Skip dictionary unit, if the testcase does not contain it.
 563       if (StartPos == Data.end())
 564         continue;
 565
 566       ++Usages[i];
 567       while (StartPos != Data.end()) {
 568         // Replace all occurrences of dictionary unit in the testcase.
 569         auto EndPos = StartPos + Dict[i].size();
 570         for (auto It = StartPos; It != EndPos; ++It)
 571           *It ^= 0xFF;
 572
 573         StartPos = std::search(EndPos, Data.end(),
 574                                Dict[i].begin(), Dict[i].end());
 575       }
 576
 577       // Get coverage for testcase with masked occurrences of dictionary unit.
 578       F->ExecuteCallback(Data.data(), Data.size());
 579       ModifiedFeatures.clear();
 580       TPC.CollectFeatures([&](size_t Feature) {
 581         ModifiedFeatures.push_back(Feature);
 582       });
 583
 584       if (InitialFeatures == ModifiedFeatures)
 585         --Scores[i];
 586       else
 587         Scores[i] += 2;
 588     }
 589   }
 590
 591   Printf("###### Useless dictionary elements. ######\n");
 592   for (size_t i = 0; i < Dict.size(); ++i) {
 593     // Dictionary units with positive score are treated as useful ones.
 594     if (Scores[i] > 0)
 595        continue;
 596
 597     Printf("\"");
 598     PrintASCII(Dict[i].data(), Dict[i].size(), "\"");
 599     Printf(" # Score: %d, Used: %d\n", Scores[i], Usages[i]);
 600   }
 601   Printf("###### End of useless dictionary elements. ######\n");
 602   return 0;
 603 }
 604
 605 std::vector<std::string> ParseSeedInuts(const char *seed_inputs) {
 606   // Parse -seed_inputs=file1,file2,... or -seed_inputs=@seed_inputs_file
 607   std::vector<std::string> Files;
 608   if (!seed_inputs) return Files;
 609   std::string SeedInputs;
 610   if (Flags.seed_inputs[0] == '@')
 611     SeedInputs = FileToString(Flags.seed_inputs + 1); // File contains list.
 612   else
 613     SeedInputs = Flags.seed_inputs; // seed_inputs contains the list.
 614   if (SeedInputs.empty()) {
 615     Printf("seed_inputs is empty or @file does not exist.\n");
 616     exit(1);
 617   }
 618   // Parse SeedInputs.
 619   size_t comma_pos = 0;
 620   while ((comma_pos = SeedInputs.find_last_of(',')) != std::string::npos) {
 621     Files.push_back(SeedInputs.substr(comma_pos + 1));
 622     SeedInputs = SeedInputs.substr(0, comma_pos);
 623   }
 624   Files.push_back(SeedInputs);
 625   return Files;
 626 }
 627
 628 static std::vector<SizedFile>
 629 ReadCorpora(const std::vector<std::string> &CorpusDirs,
 630             const std::vector<std::string> &ExtraSeedFiles) {
 631   std::vector<SizedFile> SizedFiles;
 632   size_t LastNumFiles = 0;
 633   for (auto &Dir : CorpusDirs) {
 634     GetSizedFilesFromDir(Dir, &SizedFiles);
 635     Printf("INFO: % 8zd files found in %s\n", SizedFiles.size() - LastNumFiles,
 636            Dir.c_str());
 637     LastNumFiles = SizedFiles.size();
 638   }
 639   for (auto &File : ExtraSeedFiles)
 640     if (auto Size = FileSize(File))
 641       SizedFiles.push_back({File, Size});
 642   return SizedFiles;
 643 }
 644
 645 int FuzzerDriver(int *argc, char ***argv, UserCallback Callback) {
 646   using namespace fuzzer;
 647   assert(argc && argv && "Argument pointers cannot be nullptr");
 648   std::string Argv0((*argv)[0]);
 649   EF = new ExternalFunctions();
 650   if (EF->LLVMFuzzerInitialize)
 651     EF->LLVMFuzzerInitialize(argc, argv);
 652   if (EF->__msan_scoped_disable_interceptor_checks)
 653     EF->__msan_scoped_disable_interceptor_checks();
 654   const std::vector<std::string> Args(*argv, *argv + *argc);
 655   assert(!Args.empty());
 656   ProgName = new std::string(Args[0]);
 657   if (Argv0 != *ProgName) {
 658     Printf("ERROR: argv[0] has been modified in LLVMFuzzerInitialize\n");
 659     exit(1);
 660   }
 661   ParseFlags(Args, EF);
 662   if (Flags.help) {
 663     PrintHelp();
 664     return 0;
 665   }
 666
 667   if (Flags.close_fd_mask & 2)
 668     DupAndCloseStderr();
 669   if (Flags.close_fd_mask & 1)
 670     CloseStdout();
 671
 672   if (Flags.jobs > 0 && Flags.workers == 0) {
 673     Flags.workers = std::min(NumberOfCpuCores() / 2, Flags.jobs);
 674     if (Flags.workers > 1)
 675       Printf("Running %u workers\n", Flags.workers);
 676   }
 677
 678   if (Flags.workers > 0 && Flags.jobs > 0)
 679     return RunInMultipleProcesses(Args, Flags.workers, Flags.jobs);
 680
 681   FuzzingOptions Options;
 682   Options.Verbosity = Flags.verbosity;
 683   Options.MaxLen = Flags.max_len;
 684   Options.LenControl = Flags.len_control;
 685   Options.KeepSeed = Flags.keep_seed;
 686   Options.UnitTimeoutSec = Flags.timeout;
 687   Options.ErrorExitCode = Flags.error_exitcode;
 688   Options.TimeoutExitCode = Flags.timeout_exitcode;
 689   Options.IgnoreTimeouts = Flags.ignore_timeouts;
 690   Options.IgnoreOOMs = Flags.ignore_ooms;
 691   Options.IgnoreCrashes = Flags.ignore_crashes;
 692   Options.MaxTotalTimeSec = Flags.max_total_time;
 693   Options.DoCrossOver = Flags.cross_over;
 694   Options.CrossOverUniformDist = Flags.cross_over_uniform_dist;
 695   Options.MutateDepth = Flags.mutate_depth;
 696   Options.ReduceDepth = Flags.reduce_depth;
 697   Options.UseCounters = Flags.use_counters;
 698   Options.UseMemmem = Flags.use_memmem;
 699   Options.UseCmp = Flags.use_cmp;
 700   Options.UseValueProfile = Flags.use_value_profile;
 701   Options.Shrink = Flags.shrink;
 702   Options.ReduceInputs = Flags.reduce_inputs;
 703   Options.ShuffleAtStartUp = Flags.shuffle;
 704   Options.PreferSmall = Flags.prefer_small;
 705   Options.ReloadIntervalSec = Flags.reload;
 706   Options.OnlyASCII = Flags.only_ascii;
 707   Options.DetectLeaks = Flags.detect_leaks;
 708   Options.PurgeAllocatorIntervalSec = Flags.purge_allocator_interval;
 709   Options.TraceMalloc = Flags.trace_malloc;
 710   Options.RssLimitMb = Flags.rss_limit_mb;
 711   Options.MallocLimitMb = Flags.malloc_limit_mb;
 712   if (!Options.MallocLimitMb)
 713     Options.MallocLimitMb = Options.RssLimitMb;
 714   if (Flags.runs >= 0)
 715     Options.MaxNumberOfRuns = Flags.runs;
 716   if (!Inputs->empty() && !Flags.minimize_crash_internal_step) {
 717     // Ensure output corpus assumed to be the first arbitrary argument input
 718     // is not a path to an existing file.
 719     std::string OutputCorpusDir = (*Inputs)[0];
 720     if (!IsFile(OutputCorpusDir)) {
 721       Options.OutputCorpus = OutputCorpusDir;
 722       ValidateDirectoryExists(Options.OutputCorpus, Flags.create_missing_dirs);
 723     }
 724   }
 725   Options.ReportSlowUnits = Flags.report_slow_units;
 726   if (Flags.artifact_prefix) {
 727     Options.ArtifactPrefix = Flags.artifact_prefix;
 728
 729     // Since the prefix could be a full path to a file name prefix, assume
 730     // that if the path ends with the platform's separator that a directory
 731     // is desired
 732     std::string ArtifactPathDir = Options.ArtifactPrefix;
 733     if (!IsSeparator(ArtifactPathDir[ArtifactPathDir.length() - 1])) {
 734       ArtifactPathDir = DirName(ArtifactPathDir);
 735     }
 736     ValidateDirectoryExists(ArtifactPathDir, Flags.create_missing_dirs);
 737   }
 738   if (Flags.exact_artifact_path) {
 739     Options.ExactArtifactPath = Flags.exact_artifact_path;
 740     ValidateDirectoryExists(DirName(Options.ExactArtifactPath),
 741                             Flags.create_missing_dirs);
 742   }
 743   std::vector<Unit> Dictionary;
 744   if (Flags.dict)
 745     if (!ParseDictionaryFile(FileToString(Flags.dict), &Dictionary))
 746       return 1;
 747   if (Flags.verbosity > 0 && !Dictionary.empty())
 748     Printf("Dictionary: %zd entries\n", Dictionary.size());
 749   bool RunIndividualFiles = AllInputsAreFiles();
 750   Options.SaveArtifacts =
 751       !RunIndividualFiles || Flags.minimize_crash_internal_step;
 752   Options.PrintNewCovPcs = Flags.print_pcs;
 753   Options.PrintNewCovFuncs = Flags.print_funcs;
 754   Options.PrintFinalStats = Flags.print_final_stats;
 755   Options.PrintCorpusStats = Flags.print_corpus_stats;
 756   Options.PrintCoverage = Flags.print_coverage;
 757   Options.PrintFullCoverage = Flags.print_full_coverage;
 758   if (Flags.exit_on_src_pos)
 759     Options.ExitOnSrcPos = Flags.exit_on_src_pos;
 760   if (Flags.exit_on_item)
 761     Options.ExitOnItem = Flags.exit_on_item;
 762   if (Flags.focus_function)
 763     Options.FocusFunction = Flags.focus_function;
 764   if (Flags.data_flow_trace)
 765     Options.DataFlowTrace = Flags.data_flow_trace;
 766   if (Flags.features_dir) {
 767     Options.FeaturesDir = Flags.features_dir;
 768     ValidateDirectoryExists(Options.FeaturesDir, Flags.create_missing_dirs);
 769   }
 770   if (Flags.mutation_graph_file)
 771     Options.MutationGraphFile = Flags.mutation_graph_file;
 772   if (Flags.collect_data_flow)
 773     Options.CollectDataFlow = Flags.collect_data_flow;
 774   if (Flags.stop_file)
 775     Options.StopFile = Flags.stop_file;
 776   Options.Entropic = Flags.entropic;
 777   Options.EntropicFeatureFrequencyThreshold =
 778       (size_t)Flags.entropic_feature_frequency_threshold;
 779   Options.EntropicNumberOfRarestFeatures =
 780       (size_t)Flags.entropic_number_of_rarest_features;
 781   Options.EntropicScalePerExecTime = Flags.entropic_scale_per_exec_time;
 782   if (!Options.FocusFunction.empty())
 783     Options.Entropic = false; // FocusFunction overrides entropic scheduling.
 784   if (Options.Entropic)
 785     Printf("INFO: Running with entropic power schedule (0x%zX, %zu).\n",
 786            Options.EntropicFeatureFrequencyThreshold,
 787            Options.EntropicNumberOfRarestFeatures);
 788   struct EntropicOptions Entropic;
 789   Entropic.Enabled = Options.Entropic;
 790   Entropic.FeatureFrequencyThreshold =
 791       Options.EntropicFeatureFrequencyThreshold;
 792   Entropic.NumberOfRarestFeatures = Options.EntropicNumberOfRarestFeatures;
 793   Entropic.ScalePerExecTime = Options.EntropicScalePerExecTime;
 794
 795   unsigned Seed = Flags.seed;
 796   // Initialize Seed.
 797   if (Seed == 0)
 798     Seed = static_cast<unsigned>(
 799         std::chrono::system_clock::now().time_since_epoch().count() + GetPid());
 800   if (Flags.verbosity)
 801     Printf("INFO: Seed: %u\n", Seed);
 802
 803   if (Flags.collect_data_flow && Flags.data_flow_trace && !Flags.fork &&
 804       !(Flags.merge || Flags.set_cover_merge)) {
 805     if (RunIndividualFiles)
 806       return CollectDataFlow(Flags.collect_data_flow, Flags.data_flow_trace,
 807                         ReadCorpora({}, *Inputs));
 808     else
 809       return CollectDataFlow(Flags.collect_data_flow, Flags.data_flow_trace,
 810                         ReadCorpora(*Inputs, {}));
 811   }
 812
 813   Random Rand(Seed);
 814   auto *MD = new MutationDispatcher(Rand, Options);
 815   auto *Corpus = new InputCorpus(Options.OutputCorpus, Entropic);
 816   auto *F = new Fuzzer(Callback, *Corpus, *MD, Options);
 817
 818   for (auto &U: Dictionary)
 819     if (U.size() <= Word::GetMaxSize())
 820       MD->AddWordToManualDictionary(Word(U.data(), U.size()));
 821
 822       // Threads are only supported by Chrome. Don't use them with emscripten
 823       // for now.
 824 #if !LIBFUZZER_EMSCRIPTEN
 825   StartRssThread(F, Flags.rss_limit_mb);
 826 #endif // LIBFUZZER_EMSCRIPTEN
 827
 828   Options.HandleAbrt = Flags.handle_abrt;
 829   Options.HandleAlrm = !Flags.minimize_crash;
 830   Options.HandleBus = Flags.handle_bus;
 831   Options.HandleFpe = Flags.handle_fpe;
 832   Options.HandleIll = Flags.handle_ill;
 833   Options.HandleInt = Flags.handle_int;
 834   Options.HandleSegv = Flags.handle_segv;
 835   Options.HandleTerm = Flags.handle_term;
 836   Options.HandleXfsz = Flags.handle_xfsz;
 837   Options.HandleUsr1 = Flags.handle_usr1;
 838   Options.HandleUsr2 = Flags.handle_usr2;
 839   Options.HandleWinExcept = Flags.handle_winexcept;
 840
 841   SetSignalHandler(Options);
 842
 843   std::atexit(Fuzzer::StaticExitCallback);
 844
 845   if (Flags.minimize_crash)
 846     return MinimizeCrashInput(Args, Options);
 847
 848   if (Flags.minimize_crash_internal_step)
 849     return MinimizeCrashInputInternalStep(F, Corpus);
 850
 851   if (Flags.cleanse_crash)
 852     return CleanseCrashInput(Args, Options);
 853
 854   if (RunIndividualFiles) {
 855     Options.SaveArtifacts = false;
 856     int Runs = std::max(1, Flags.runs);
 857     Printf("%s: Running %zd inputs %d time(s) each.\n", ProgName->c_str(),
 858            Inputs->size(), Runs);
 859     for (auto &Path : *Inputs) {
 860       auto StartTime = system_clock::now();
 861       Printf("Running: %s\n", Path.c_str());
 862       for (int Iter = 0; Iter < Runs; Iter++)
 863         RunOneTest(F, Path.c_str(), Options.MaxLen);
 864       auto StopTime = system_clock::now();
 865       auto MS = duration_cast<milliseconds>(StopTime - StartTime).count();
 866       Printf("Executed %s in %ld ms\n", Path.c_str(), (long)MS);
 867     }
 868     Printf("***\n"
 869            "*** NOTE: fuzzing was not performed, you have only\n"
 870            "***       executed the target code on a fixed set of inputs.\n"
 871            "***\n");
 872     F->PrintFinalStats();
 873     exit(0);
 874   }
 875
 876   Options.ForkCorpusGroups = Flags.fork_corpus_groups;
 877   if (Flags.fork)
 878     FuzzWithFork(F->GetMD().GetRand(), Options, Args, *Inputs, Flags.fork);
 879
 880   if (Flags.merge || Flags.set_cover_merge)
 881     Merge(F, Options, Args, *Inputs, Flags.merge_control_file);
 882
 883   if (Flags.merge_inner) {
 884     const size_t kDefaultMaxMergeLen = 1 << 20;
 885     if (Options.MaxLen == 0)
 886       F->SetMaxInputLen(kDefaultMaxMergeLen);
 887     assert(Flags.merge_control_file);
 888     F->CrashResistantMergeInternalStep(Flags.merge_control_file,
 889                                        !strncmp(Flags.merge_inner, "2", 1));
 890     exit(0);
 891   }
 892
 893   if (Flags.analyze_dict) {
 894     size_t MaxLen = INT_MAX;  // Large max length.
 895     UnitVector InitialCorpus;
 896     for (auto &Inp : *Inputs) {
 897       Printf("Loading corpus dir: %s\n", Inp.c_str());
 898       ReadDirToVectorOfUnits(Inp.c_str(), &InitialCorpus, nullptr,
 899                              MaxLen, /*ExitOnError=*/false);
 900     }
 901
 902     if (Dictionary.empty() || Inputs->empty()) {
 903       Printf("ERROR: can't analyze dict without dict and corpus provided\n");
 904       return 1;
 905     }
 906     if (AnalyzeDictionary(F, Dictionary, InitialCorpus)) {
 907       Printf("Dictionary analysis failed\n");
 908       exit(1);
 909     }
 910     Printf("Dictionary analysis succeeded\n");
 911     exit(0);
 912   }
 913
 914   auto CorporaFiles = ReadCorpora(*Inputs, ParseSeedInuts(Flags.seed_inputs));
 915   F->Loop(CorporaFiles);
 916
 917   if (Flags.verbosity)
 918     Printf("Done %zd runs in %zd second(s)\n", F->getTotalNumberOfRuns(),
 919            F->secondsSinceProcessStartUp());
 920   F->PrintFinalStats();
 921
 922   exit(0);  // Don't let F destroy itself.
 923 }
 924
 925 extern "C" ATTRIBUTE_INTERFACE int
 926 LLVMFuzzerRunDriver(int *argc, char ***argv,
 927                     int (*UserCb)(const uint8_t *Data, size_t Size)) {
 928   return FuzzerDriver(argc, argv, UserCb);
 929 }
 930
 931 // Storage for global ExternalFunctions object.
 932 ExternalFunctions *EF = nullptr;
 933
 934 }  // namespace fuzzer