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//===- FuzzerUtilPosix.cpp - Misc utils for Posix. ------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
// Misc utils implementation using Posix API.
//===----------------------------------------------------------------------===//
#include "FuzzerPlatform.h"
#if LIBFUZZER_POSIX
#include "FuzzerIO.h"
#include "FuzzerInternal.h"
#include "FuzzerTracePC.h"
#include <cassert>
#include <chrono>
#include <cstring>
#include <errno.h>
#include <iomanip>
#include <signal.h>
#include <stdio.h>
#include <sys/mman.h>
#include <sys/resource.h>
#include <sys/syscall.h>
#include <sys/time.h>
#include <sys/types.h>
#include <thread>
#include <unistd.h>
namespace fuzzer {
static void AlarmHandler(int, siginfo_t *, void *) {
Fuzzer::StaticAlarmCallback();
}
static void (*upstream_segv_handler)(int, siginfo_t *, void *);
static void SegvHandler(int sig, siginfo_t *si, void *ucontext) {
assert(si->si_signo == SIGSEGV);
if (upstream_segv_handler)
return upstream_segv_handler(sig, si, ucontext);
Fuzzer::StaticCrashSignalCallback();
}
static void CrashHandler(int, siginfo_t *, void *) {
Fuzzer::StaticCrashSignalCallback();
}
static void InterruptHandler(int, siginfo_t *, void *) {
Fuzzer::StaticInterruptCallback();
}
static void GracefulExitHandler(int, siginfo_t *, void *) {
Fuzzer::StaticGracefulExitCallback();
}
static void FileSizeExceedHandler(int, siginfo_t *, void *) {
Fuzzer::StaticFileSizeExceedCallback();
}
static void SetSigaction(int signum,
void (*callback)(int, siginfo_t *, void *)) {
struct sigaction sigact = {};
if (sigaction(signum, nullptr, &sigact)) {
Printf("libFuzzer: sigaction failed with %d\n", errno);
exit(1);
}
if (sigact.sa_flags & SA_SIGINFO) {
if (sigact.sa_sigaction) {
if (signum != SIGSEGV)
return;
upstream_segv_handler = sigact.sa_sigaction;
}
} else {
if (sigact.sa_handler != SIG_DFL && sigact.sa_handler != SIG_IGN &&
sigact.sa_handler != SIG_ERR)
return;
}
struct sigaction new_sigact = {};
// Address sanitizer needs SA_ONSTACK (causing the signal handler to run on a
// dedicated stack) in order to be able to detect stack overflows; keep the
// flag if it's set.
new_sigact.sa_flags = SA_SIGINFO | (sigact.sa_flags & SA_ONSTACK);
new_sigact.sa_sigaction = callback;
if (sigaction(signum, &new_sigact, nullptr)) {
Printf("libFuzzer: sigaction failed with %d\n", errno);
exit(1);
}
}
// Return true on success, false otherwise.
bool ExecuteCommand(const Command &Cmd, std::string *CmdOutput) {
FILE *Pipe = popen(Cmd.toString().c_str(), "r");
if (!Pipe)
return false;
if (CmdOutput) {
char TmpBuffer[128];
while (fgets(TmpBuffer, sizeof(TmpBuffer), Pipe))
CmdOutput->append(TmpBuffer);
}
return pclose(Pipe) == 0;
}
void SetTimer(int Seconds) {
struct itimerval T {
{Seconds, 0}, { Seconds, 0 }
};
if (setitimer(ITIMER_REAL, &T, nullptr)) {
Printf("libFuzzer: setitimer failed with %d\n", errno);
exit(1);
}
SetSigaction(SIGALRM, AlarmHandler);
}
void SetSignalHandler(const FuzzingOptions& Options) {
// setitimer is not implemented in emscripten.
if (Options.HandleAlrm && Options.UnitTimeoutSec > 0 && !LIBFUZZER_EMSCRIPTEN)
SetTimer(Options.UnitTimeoutSec / 2 + 1);
if (Options.HandleInt)
SetSigaction(SIGINT, InterruptHandler);
if (Options.HandleTerm)
SetSigaction(SIGTERM, InterruptHandler);
if (Options.HandleSegv)
SetSigaction(SIGSEGV, SegvHandler);
if (Options.HandleBus)
SetSigaction(SIGBUS, CrashHandler);
if (Options.HandleAbrt)
SetSigaction(SIGABRT, CrashHandler);
if (Options.HandleIll)
SetSigaction(SIGILL, CrashHandler);
if (Options.HandleFpe)
SetSigaction(SIGFPE, CrashHandler);
if (Options.HandleXfsz)
SetSigaction(SIGXFSZ, FileSizeExceedHandler);
if (Options.HandleUsr1)
SetSigaction(SIGUSR1, GracefulExitHandler);
if (Options.HandleUsr2)
SetSigaction(SIGUSR2, GracefulExitHandler);
}
void SleepSeconds(int Seconds) {
sleep(Seconds); // Use C API to avoid coverage from instrumented libc++.
}
unsigned long GetPid() { return (unsigned long)getpid(); }
size_t GetPeakRSSMb() {
struct rusage usage;
if (getrusage(RUSAGE_SELF, &usage))
return 0;
if (LIBFUZZER_LINUX || LIBFUZZER_FREEBSD || LIBFUZZER_NETBSD ||
LIBFUZZER_EMSCRIPTEN) {
// ru_maxrss is in KiB
return usage.ru_maxrss >> 10;
} else if (LIBFUZZER_APPLE) {
// ru_maxrss is in bytes
return usage.ru_maxrss >> 20;
}
assert(0 && "GetPeakRSSMb() is not implemented for your platform");
return 0;
}
FILE *OpenProcessPipe(const char *Command, const char *Mode) {
return popen(Command, Mode);
}
int CloseProcessPipe(FILE *F) {
return pclose(F);
}
const void *SearchMemory(const void *Data, size_t DataLen, const void *Patt,
size_t PattLen) {
return memmem(Data, DataLen, Patt, PattLen);
}
std::string DisassembleCmd(const std::string &FileName) {
return "objdump -d " + FileName;
}
std::string SearchRegexCmd(const std::string &Regex) {
return "grep '" + Regex + "'";
}
} // namespace fuzzer
#endif // LIBFUZZER_POSIX
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