tools/fuzzing/libfuzzer/FuzzerUtilPosix.cpp

   1 //===- FuzzerUtilPosix.cpp - Misc utils for Posix. ------------------------===//
   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 // Misc utils implementation using Posix API.
   9 //===----------------------------------------------------------------------===//
  10 #include "FuzzerPlatform.h"
  11 #if LIBFUZZER_POSIX
  12 #include "FuzzerIO.h"
  13 #include "FuzzerInternal.h"
  14 #include "FuzzerTracePC.h"
  15 #include <cassert>
  16 #include <chrono>
  17 #include <cstring>
  18 #include <errno.h>
  19 #include <iomanip>
  20 #include <signal.h>
  21 #include <stdio.h>
  22 #include <sys/mman.h>
  23 #include <sys/resource.h>
  24 #include <sys/syscall.h>
  25 #include <sys/time.h>
  26 #include <sys/types.h>
  27 #include <thread>
  28 #include <unistd.h>
  29
  30 namespace fuzzer {
  31
  32 static void AlarmHandler(int, siginfo_t *, void *) {
  33   Fuzzer::StaticAlarmCallback();
  34 }
  35
  36 static void (*upstream_segv_handler)(int, siginfo_t *, void *);
  37
  38 static void SegvHandler(int sig, siginfo_t *si, void *ucontext) {
  39   assert(si->si_signo == SIGSEGV);
  40   if (upstream_segv_handler)
  41     return upstream_segv_handler(sig, si, ucontext);
  42   Fuzzer::StaticCrashSignalCallback();
  43 }
  44
  45 static void CrashHandler(int, siginfo_t *, void *) {
  46   Fuzzer::StaticCrashSignalCallback();
  47 }
  48
  49 static void InterruptHandler(int, siginfo_t *, void *) {
  50   Fuzzer::StaticInterruptCallback();
  51 }
  52
  53 static void GracefulExitHandler(int, siginfo_t *, void *) {
  54   Fuzzer::StaticGracefulExitCallback();
  55 }
  56
  57 static void FileSizeExceedHandler(int, siginfo_t *, void *) {
  58   Fuzzer::StaticFileSizeExceedCallback();
  59 }
  60
  61 static void SetSigaction(int signum,
  62                          void (*callback)(int, siginfo_t *, void *)) {
  63   struct sigaction sigact = {};
  64   if (sigaction(signum, nullptr, &sigact)) {
  65     Printf("libFuzzer: sigaction failed with %d\n", errno);
  66     exit(1);
  67   }
  68   if (sigact.sa_flags & SA_SIGINFO) {
  69     if (sigact.sa_sigaction) {
  70       if (signum != SIGSEGV)
  71         return;
  72       upstream_segv_handler = sigact.sa_sigaction;
  73     }
  74   } else {
  75     if (sigact.sa_handler != SIG_DFL && sigact.sa_handler != SIG_IGN &&
  76         sigact.sa_handler != SIG_ERR)
  77       return;
  78   }
  79
  80   sigact = {};
  81   sigact.sa_flags = SA_SIGINFO;
  82   sigact.sa_sigaction = callback;
  83   if (sigaction(signum, &sigact, 0)) {
  84     Printf("libFuzzer: sigaction failed with %d\n", errno);
  85     exit(1);
  86   }
  87 }
  88
  89 // Return true on success, false otherwise.
  90 bool ExecuteCommand(const Command &Cmd, std::string *CmdOutput) {
  91   FILE *Pipe = popen(Cmd.toString().c_str(), "r");
  92   if (!Pipe)
  93     return false;
  94
  95   if (CmdOutput) {
  96     char TmpBuffer[128];
  97     while (fgets(TmpBuffer, sizeof(TmpBuffer), Pipe))
  98       CmdOutput->append(TmpBuffer);
  99   }
 100   return pclose(Pipe) == 0;
 101 }
 102
 103 void SetTimer(int Seconds) {
 104   struct itimerval T {
 105     {Seconds, 0}, { Seconds, 0 }
 106   };
 107   if (setitimer(ITIMER_REAL, &T, nullptr)) {
 108     Printf("libFuzzer: setitimer failed with %d\n", errno);
 109     exit(1);
 110   }
 111   SetSigaction(SIGALRM, AlarmHandler);
 112 }
 113
 114 void SetSignalHandler(const FuzzingOptions& Options) {
 115   // setitimer is not implemented in emscripten.
 116   if (Options.UnitTimeoutSec > 0 && !LIBFUZZER_EMSCRIPTEN)
 117     SetTimer(Options.UnitTimeoutSec / 2 + 1);
 118   if (Options.HandleInt)
 119     SetSigaction(SIGINT, InterruptHandler);
 120   if (Options.HandleTerm)
 121     SetSigaction(SIGTERM, InterruptHandler);
 122   if (Options.HandleSegv)
 123     SetSigaction(SIGSEGV, SegvHandler);
 124   if (Options.HandleBus)
 125     SetSigaction(SIGBUS, CrashHandler);
 126   if (Options.HandleAbrt)
 127     SetSigaction(SIGABRT, CrashHandler);
 128   if (Options.HandleIll)
 129     SetSigaction(SIGILL, CrashHandler);
 130   if (Options.HandleFpe)
 131     SetSigaction(SIGFPE, CrashHandler);
 132   if (Options.HandleXfsz)
 133     SetSigaction(SIGXFSZ, FileSizeExceedHandler);
 134   if (Options.HandleUsr1)
 135     SetSigaction(SIGUSR1, GracefulExitHandler);
 136   if (Options.HandleUsr2)
 137     SetSigaction(SIGUSR2, GracefulExitHandler);
 138 }
 139
 140 void SleepSeconds(int Seconds) {
 141   sleep(Seconds); // Use C API to avoid coverage from instrumented libc++.
 142 }
 143
 144 unsigned long GetPid() { return (unsigned long)getpid(); }
 145
 146 size_t GetPeakRSSMb() {
 147   struct rusage usage;
 148   if (getrusage(RUSAGE_SELF, &usage))
 149     return 0;
 150   if (LIBFUZZER_LINUX || LIBFUZZER_FREEBSD || LIBFUZZER_NETBSD ||
 151       LIBFUZZER_OPENBSD || LIBFUZZER_EMSCRIPTEN) {
 152     // ru_maxrss is in KiB
 153     return usage.ru_maxrss >> 10;
 154   } else if (LIBFUZZER_APPLE) {
 155     // ru_maxrss is in bytes
 156     return usage.ru_maxrss >> 20;
 157   }
 158   assert(0 && "GetPeakRSSMb() is not implemented for your platform");
 159   return 0;
 160 }
 161
 162 FILE *OpenProcessPipe(const char *Command, const char *Mode) {
 163   return popen(Command, Mode);
 164 }
 165
 166 int CloseProcessPipe(FILE *F) {
 167   return pclose(F);
 168 }
 169
 170 const void *SearchMemory(const void *Data, size_t DataLen, const void *Patt,
 171                          size_t PattLen) {
 172   return memmem(Data, DataLen, Patt, PattLen);
 173 }
 174
 175 std::string DisassembleCmd(const std::string &FileName) {
 176   return "objdump -d " + FileName;
 177 }
 178
 179 std::string SearchRegexCmd(const std::string &Regex) {
 180   return "grep '" + Regex + "'";
 181 }
 182
 183 }  // namespace fuzzer
 184
 185 #endif // LIBFUZZER_POSIX