1 //===- FuzzerDriver.cpp - FuzzerDriver function and flags -----------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 // FuzzerDriver and flag parsing.
10 //===----------------------------------------------------------------------===//
11
12 #include "FuzzerInterface.h"
13 #include "FuzzerInternal.h"
14
15 #include <algorithm>
16 #include <atomic>
17 #include <chrono>
18 #include <cstring>
19 #include <mutex>
20 #include <string>
21 #include <thread>
22 #include <unistd.h>
23
24 // This function should be present in the libFuzzer so that the client
25 // binary can test for its existence.
__libfuzzer_is_present()26 extern "C" __attribute__((used)) void __libfuzzer_is_present() {}
27
28 namespace fuzzer {
29
30 // Program arguments.
31 struct FlagDescription {
32 const char *Name;
33 const char *Description;
34 int Default;
35 int *IntFlag;
36 const char **StrFlag;
37 unsigned int *UIntFlag;
38 };
39
40 struct {
41 #define FUZZER_DEPRECATED_FLAG(Name)
42 #define FUZZER_FLAG_INT(Name, Default, Description) int Name;
43 #define FUZZER_FLAG_UNSIGNED(Name, Default, Description) unsigned int Name;
44 #define FUZZER_FLAG_STRING(Name, Description) const char *Name;
45 #include "FuzzerFlags.def"
46 #undef FUZZER_DEPRECATED_FLAG
47 #undef FUZZER_FLAG_INT
48 #undef FUZZER_FLAG_UNSIGNED
49 #undef FUZZER_FLAG_STRING
50 } Flags;
51
52 static const FlagDescription FlagDescriptions [] {
53 #define FUZZER_DEPRECATED_FLAG(Name) \
54 {#Name, "Deprecated; don't use", 0, nullptr, nullptr, nullptr},
55 #define FUZZER_FLAG_INT(Name, Default, Description) \
56 {#Name, Description, Default, &Flags.Name, nullptr, nullptr},
57 #define FUZZER_FLAG_UNSIGNED(Name, Default, Description) \
58 {#Name, Description, static_cast<int>(Default), \
59 nullptr, nullptr, &Flags.Name},
60 #define FUZZER_FLAG_STRING(Name, Description) \
61 {#Name, Description, 0, nullptr, &Flags.Name, nullptr},
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 };
68
69 static const size_t kNumFlags =
70 sizeof(FlagDescriptions) / sizeof(FlagDescriptions[0]);
71
72 static std::vector<std::string> *Inputs;
73 static std::string *ProgName;
74
PrintHelp()75 static void PrintHelp() {
76 Printf("Usage:\n");
77 auto Prog = ProgName->c_str();
78 Printf("\nTo run fuzzing pass 0 or more directories.\n");
79 Printf("%s [-flag1=val1 [-flag2=val2 ...] ] [dir1 [dir2 ...] ]\n", Prog);
80
81 Printf("\nTo run individual tests without fuzzing pass 1 or more files:\n");
82 Printf("%s [-flag1=val1 [-flag2=val2 ...] ] file1 [file2 ...]\n", Prog);
83
84 Printf("\nFlags: (strictly in form -flag=value)\n");
85 size_t MaxFlagLen = 0;
86 for (size_t F = 0; F < kNumFlags; F++)
87 MaxFlagLen = std::max(strlen(FlagDescriptions[F].Name), MaxFlagLen);
88
89 for (size_t F = 0; F < kNumFlags; F++) {
90 const auto &D = FlagDescriptions[F];
91 Printf(" %s", D.Name);
92 for (size_t i = 0, n = MaxFlagLen - strlen(D.Name); i < n; i++)
93 Printf(" ");
94 Printf("\t");
95 Printf("%d\t%s\n", D.Default, D.Description);
96 }
97 Printf("\nFlags starting with '--' will be ignored and "
98 "will be passed verbatim to subprocesses.\n");
99 }
100
FlagValue(const char * Param,const char * Name)101 static const char *FlagValue(const char *Param, const char *Name) {
102 size_t Len = strlen(Name);
103 if (Param[0] == '-' && strstr(Param + 1, Name) == Param + 1 &&
104 Param[Len + 1] == '=')
105 return &Param[Len + 2];
106 return nullptr;
107 }
108
109 // Avoid calling stol as it triggers a bug in clang/glibc build.
MyStol(const char * Str)110 static long MyStol(const char *Str) {
111 long Res = 0;
112 long Sign = 1;
113 if (*Str == '-') {
114 Str++;
115 Sign = -1;
116 }
117 for (size_t i = 0; Str[i]; i++) {
118 char Ch = Str[i];
119 if (Ch < '0' || Ch > '9')
120 return Res;
121 Res = Res * 10 + (Ch - '0');
122 }
123 return Res * Sign;
124 }
125
ParseOneFlag(const char * Param)126 static bool ParseOneFlag(const char *Param) {
127 if (Param[0] != '-') return false;
128 if (Param[1] == '-') {
129 static bool PrintedWarning = false;
130 if (!PrintedWarning) {
131 PrintedWarning = true;
132 Printf("INFO: libFuzzer ignores flags that start with '--'\n");
133 }
134 for (size_t F = 0; F < kNumFlags; F++)
135 if (FlagValue(Param + 1, FlagDescriptions[F].Name))
136 Printf("WARNING: did you mean '%s' (single dash)?\n", Param + 1);
137 return true;
138 }
139 for (size_t F = 0; F < kNumFlags; F++) {
140 const char *Name = FlagDescriptions[F].Name;
141 const char *Str = FlagValue(Param, Name);
142 if (Str) {
143 if (FlagDescriptions[F].IntFlag) {
144 int Val = MyStol(Str);
145 *FlagDescriptions[F].IntFlag = Val;
146 if (Flags.verbosity >= 2)
147 Printf("Flag: %s %d\n", Name, Val);;
148 return true;
149 } else if (FlagDescriptions[F].UIntFlag) {
150 unsigned int Val = std::stoul(Str);
151 *FlagDescriptions[F].UIntFlag = Val;
152 if (Flags.verbosity >= 2)
153 Printf("Flag: %s %u\n", Name, Val);
154 return true;
155 } else if (FlagDescriptions[F].StrFlag) {
156 *FlagDescriptions[F].StrFlag = Str;
157 if (Flags.verbosity >= 2)
158 Printf("Flag: %s %s\n", Name, Str);
159 return true;
160 } else { // Deprecated flag.
161 Printf("Flag: %s: deprecated, don't use\n", Name);
162 return true;
163 }
164 }
165 }
166 Printf("\n\nWARNING: unrecognized flag '%s'; "
167 "use -help=1 to list all flags\n\n", Param);
168 return true;
169 }
170
171 // We don't use any library to minimize dependencies.
ParseFlags(const std::vector<std::string> & Args)172 static void ParseFlags(const std::vector<std::string> &Args) {
173 for (size_t F = 0; F < kNumFlags; F++) {
174 if (FlagDescriptions[F].IntFlag)
175 *FlagDescriptions[F].IntFlag = FlagDescriptions[F].Default;
176 if (FlagDescriptions[F].UIntFlag)
177 *FlagDescriptions[F].UIntFlag =
178 static_cast<unsigned int>(FlagDescriptions[F].Default);
179 if (FlagDescriptions[F].StrFlag)
180 *FlagDescriptions[F].StrFlag = nullptr;
181 }
182 Inputs = new std::vector<std::string>;
183 for (size_t A = 1; A < Args.size(); A++) {
184 if (ParseOneFlag(Args[A].c_str())) continue;
185 Inputs->push_back(Args[A]);
186 }
187 }
188
189 static std::mutex Mu;
190
PulseThread()191 static void PulseThread() {
192 while (true) {
193 SleepSeconds(600);
194 std::lock_guard<std::mutex> Lock(Mu);
195 Printf("pulse...\n");
196 }
197 }
198
WorkerThread(const std::string & Cmd,std::atomic<int> * Counter,int NumJobs,std::atomic<bool> * HasErrors)199 static void WorkerThread(const std::string &Cmd, std::atomic<int> *Counter,
200 int NumJobs, std::atomic<bool> *HasErrors) {
201 while (true) {
202 int C = (*Counter)++;
203 if (C >= NumJobs) break;
204 std::string Log = "fuzz-" + std::to_string(C) + ".log";
205 std::string ToRun = Cmd + " > " + Log + " 2>&1\n";
206 if (Flags.verbosity)
207 Printf("%s", ToRun.c_str());
208 int ExitCode = ExecuteCommand(ToRun);
209 if (ExitCode != 0)
210 *HasErrors = true;
211 std::lock_guard<std::mutex> Lock(Mu);
212 Printf("================== Job %d exited with exit code %d ============\n",
213 C, ExitCode);
214 fuzzer::CopyFileToErr(Log);
215 }
216 }
217
RunInMultipleProcesses(const std::vector<std::string> & Args,int NumWorkers,int NumJobs)218 static int RunInMultipleProcesses(const std::vector<std::string> &Args,
219 int NumWorkers, int NumJobs) {
220 std::atomic<int> Counter(0);
221 std::atomic<bool> HasErrors(false);
222 std::string Cmd;
223 for (auto &S : Args) {
224 if (FlagValue(S.c_str(), "jobs") || FlagValue(S.c_str(), "workers"))
225 continue;
226 Cmd += S + " ";
227 }
228 std::vector<std::thread> V;
229 std::thread Pulse(PulseThread);
230 Pulse.detach();
231 for (int i = 0; i < NumWorkers; i++)
232 V.push_back(std::thread(WorkerThread, Cmd, &Counter, NumJobs, &HasErrors));
233 for (auto &T : V)
234 T.join();
235 return HasErrors ? 1 : 0;
236 }
237
RssThread(Fuzzer * F,size_t RssLimitMb)238 static void RssThread(Fuzzer *F, size_t RssLimitMb) {
239 while (true) {
240 SleepSeconds(1);
241 size_t Peak = GetPeakRSSMb();
242 if (Peak > RssLimitMb)
243 F->RssLimitCallback();
244 }
245 }
246
StartRssThread(Fuzzer * F,size_t RssLimitMb)247 static void StartRssThread(Fuzzer *F, size_t RssLimitMb) {
248 if (!RssLimitMb) return;
249 std::thread T(RssThread, F, RssLimitMb);
250 T.detach();
251 }
252
RunOneTest(Fuzzer * F,const char * InputFilePath)253 int RunOneTest(Fuzzer *F, const char *InputFilePath) {
254 Unit U = FileToVector(InputFilePath);
255 Unit PreciseSizedU(U);
256 assert(PreciseSizedU.size() == PreciseSizedU.capacity());
257 F->RunOne(PreciseSizedU.data(), PreciseSizedU.size());
258 return 0;
259 }
260
AllInputsAreFiles()261 static bool AllInputsAreFiles() {
262 if (Inputs->empty()) return false;
263 for (auto &Path : *Inputs)
264 if (!IsFile(Path))
265 return false;
266 return true;
267 }
268
FuzzerDriver(int * argc,char *** argv,UserCallback Callback)269 int FuzzerDriver(int *argc, char ***argv, UserCallback Callback) {
270 using namespace fuzzer;
271 assert(argc && argv && "Argument pointers cannot be nullptr");
272 EF = new ExternalFunctions();
273 if (EF->LLVMFuzzerInitialize)
274 EF->LLVMFuzzerInitialize(argc, argv);
275 const std::vector<std::string> Args(*argv, *argv + *argc);
276 assert(!Args.empty());
277 ProgName = new std::string(Args[0]);
278 ParseFlags(Args);
279 if (Flags.help) {
280 PrintHelp();
281 return 0;
282 }
283
284 if (Flags.close_fd_mask & 2)
285 DupAndCloseStderr();
286 if (Flags.close_fd_mask & 1)
287 CloseStdout();
288
289 if (Flags.jobs > 0 && Flags.workers == 0) {
290 Flags.workers = std::min(NumberOfCpuCores() / 2, Flags.jobs);
291 if (Flags.workers > 1)
292 Printf("Running %d workers\n", Flags.workers);
293 }
294
295 if (Flags.workers > 0 && Flags.jobs > 0)
296 return RunInMultipleProcesses(Args, Flags.workers, Flags.jobs);
297
298 const size_t kMaxSaneLen = 1 << 20;
299 const size_t kMinDefaultLen = 64;
300 FuzzingOptions Options;
301 Options.Verbosity = Flags.verbosity;
302 Options.MaxLen = Flags.max_len;
303 Options.UnitTimeoutSec = Flags.timeout;
304 Options.TimeoutExitCode = Flags.timeout_exitcode;
305 Options.MaxTotalTimeSec = Flags.max_total_time;
306 Options.DoCrossOver = Flags.cross_over;
307 Options.MutateDepth = Flags.mutate_depth;
308 Options.UseCounters = Flags.use_counters;
309 Options.UseIndirCalls = Flags.use_indir_calls;
310 Options.UseTraces = Flags.use_traces;
311 Options.UseMemcmp = Flags.use_memcmp;
312 Options.ShuffleAtStartUp = Flags.shuffle;
313 Options.PreferSmall = Flags.prefer_small;
314 Options.Reload = Flags.reload;
315 Options.OnlyASCII = Flags.only_ascii;
316 Options.OutputCSV = Flags.output_csv;
317 Options.DetectLeaks = Flags.detect_leaks;
318 Options.RssLimitMb = Flags.rss_limit_mb;
319 if (Flags.runs >= 0)
320 Options.MaxNumberOfRuns = Flags.runs;
321 if (!Inputs->empty())
322 Options.OutputCorpus = (*Inputs)[0];
323 Options.ReportSlowUnits = Flags.report_slow_units;
324 if (Flags.artifact_prefix)
325 Options.ArtifactPrefix = Flags.artifact_prefix;
326 if (Flags.exact_artifact_path)
327 Options.ExactArtifactPath = Flags.exact_artifact_path;
328 std::vector<Unit> Dictionary;
329 if (Flags.dict)
330 if (!ParseDictionaryFile(FileToString(Flags.dict), &Dictionary))
331 return 1;
332 if (Flags.verbosity > 0 && !Dictionary.empty())
333 Printf("Dictionary: %zd entries\n", Dictionary.size());
334 bool DoPlainRun = AllInputsAreFiles();
335 Options.SaveArtifacts = !DoPlainRun;
336 Options.PrintNewCovPcs = Flags.print_new_cov_pcs;
337 Options.PrintFinalStats = Flags.print_final_stats;
338 Options.TruncateUnits = Flags.truncate_units;
339 Options.PruneCorpus = Flags.prune_corpus;
340
341 unsigned Seed = Flags.seed;
342 // Initialize Seed.
343 if (Seed == 0)
344 Seed = (std::chrono::system_clock::now().time_since_epoch().count() << 10) +
345 getpid();
346 if (Flags.verbosity)
347 Printf("INFO: Seed: %u\n", Seed);
348
349 Random Rand(Seed);
350 MutationDispatcher MD(Rand, Options);
351 Fuzzer F(Callback, MD, Options);
352
353 for (auto &U: Dictionary)
354 if (U.size() <= Word::GetMaxSize())
355 MD.AddWordToManualDictionary(Word(U.data(), U.size()));
356
357 StartRssThread(&F, Flags.rss_limit_mb);
358
359 // Timer
360 if (Flags.timeout > 0)
361 SetTimer(Flags.timeout / 2 + 1);
362 if (Flags.handle_segv) SetSigSegvHandler();
363 if (Flags.handle_bus) SetSigBusHandler();
364 if (Flags.handle_abrt) SetSigAbrtHandler();
365 if (Flags.handle_ill) SetSigIllHandler();
366 if (Flags.handle_fpe) SetSigFpeHandler();
367 if (Flags.handle_int) SetSigIntHandler();
368 if (Flags.handle_term) SetSigTermHandler();
369
370 if (DoPlainRun) {
371 Options.SaveArtifacts = false;
372 int Runs = std::max(1, Flags.runs);
373 Printf("%s: Running %zd inputs %d time(s) each.\n", ProgName->c_str(),
374 Inputs->size(), Runs);
375 for (auto &Path : *Inputs) {
376 auto StartTime = system_clock::now();
377 Printf("Running: %s\n", Path.c_str());
378 for (int Iter = 0; Iter < Runs; Iter++)
379 RunOneTest(&F, Path.c_str());
380 auto StopTime = system_clock::now();
381 auto MS = duration_cast<milliseconds>(StopTime - StartTime).count();
382 Printf("Executed %s in %zd ms\n", Path.c_str(), (long)MS);
383 }
384 F.PrintFinalStats();
385 exit(0);
386 }
387
388
389 if (Flags.merge) {
390 if (Options.MaxLen == 0)
391 F.SetMaxLen(kMaxSaneLen);
392 F.Merge(*Inputs);
393 exit(0);
394 }
395
396 size_t TemporaryMaxLen = Options.MaxLen ? Options.MaxLen : kMaxSaneLen;
397
398 F.RereadOutputCorpus(TemporaryMaxLen);
399 for (auto &inp : *Inputs)
400 if (inp != Options.OutputCorpus)
401 F.ReadDir(inp, nullptr, TemporaryMaxLen);
402
403 if (Options.MaxLen == 0)
404 F.SetMaxLen(
405 std::min(std::max(kMinDefaultLen, F.MaxUnitSizeInCorpus()), kMaxSaneLen));
406
407 if (F.CorpusSize() == 0) {
408 F.AddToCorpus(Unit()); // Can't fuzz empty corpus, so add an empty input.
409 if (Options.Verbosity)
410 Printf("INFO: A corpus is not provided, starting from an empty corpus\n");
411 }
412 F.ShuffleAndMinimize();
413 if (Flags.drill)
414 F.Drill();
415 else
416 F.Loop();
417
418 if (Flags.verbosity)
419 Printf("Done %d runs in %zd second(s)\n", F.getTotalNumberOfRuns(),
420 F.secondsSinceProcessStartUp());
421 F.PrintFinalStats();
422
423 exit(0); // Don't let F destroy itself.
424 }
425
426 // Storage for global ExternalFunctions object.
427 ExternalFunctions *EF = nullptr;
428
429 } // namespace fuzzer
430