llvm-project/llvm/lib/Fuzzer/FuzzerIO.cpp

//===- FuzzerIO.cpp - IO utils. -------------------------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// IO functions.
//===----------------------------------------------------------------------===//
#include "FuzzerInternal.h"
#include <iterator>
#include <fstream>
#include <dirent.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <cstdarg>
#include <cstdio>

extern "C" {
__attribute__((weak)) void __sanitizer_set_report_fd(void *);
}

namespace fuzzer {

static FILE *OutputFile = stderr;

bool IsFile(const std::string &Path) {
  struct stat St;
  if (stat(Path.c_str(), &St))
    return false;
  return S_ISREG(St.st_mode);
}

static long GetEpoch(const std::string &Path) {
  struct stat St;
  if (stat(Path.c_str(), &St))
    return 0;  // Can't stat, be conservative.
  return St.st_mtime;
}

static void ListFilesInDirRecursive(const std::string &Dir, long *Epoch,
                                    std::vector<std::string> *V, bool TopDir) {
  auto E = GetEpoch(Dir);
  if (Epoch)
    if (E && *Epoch >= E) return;

  DIR *D = opendir(Dir.c_str());
  if (!D) {
    Printf("No such directory: %s; exiting\n", Dir.c_str());
    exit(1);
  }
  while (auto E = readdir(D)) {
    std::string Path = DirPlusFile(Dir, E->d_name);
    if (E->d_type == DT_REG || E->d_type == DT_LNK)
      V->push_back(Path);
    else if (E->d_type == DT_DIR && *E->d_name != '.')
      ListFilesInDirRecursive(Path, Epoch, V, false);
  }
  closedir(D);
  if (Epoch && TopDir)
    *Epoch = E;
}

Unit FileToVector(const std::string &Path, size_t MaxSize) {
  std::ifstream T(Path);
  if (!T) {
    Printf("No such directory: %s; exiting\n", Path.c_str());
    exit(1);
  }

  T.seekg(0, T.end);
  size_t FileLen = T.tellg();
  if (MaxSize)
    FileLen = std::min(FileLen, MaxSize);

  T.seekg(0, T.beg);
  Unit Res(FileLen);
  T.read(reinterpret_cast<char *>(Res.data()), FileLen);
  return Res;
}

std::string FileToString(const std::string &Path) {
  std::ifstream T(Path);
  return std::string((std::istreambuf_iterator<char>(T)),
                     std::istreambuf_iterator<char>());
}

void CopyFileToErr(const std::string &Path) {
  Printf("%s", FileToString(Path).c_str());
}

void WriteToFile(const Unit &U, const std::string &Path) {
  // Use raw C interface because this function may be called from a sig handler.
  FILE *Out = fopen(Path.c_str(), "w");
  if (!Out) return;
  fwrite(U.data(), sizeof(U[0]), U.size(), Out);
  fclose(Out);
}

void ReadDirToVectorOfUnits(const char *Path, std::vector<Unit> *V,
                            long *Epoch, size_t MaxSize) {
  long E = Epoch ? *Epoch : 0;
  std::vector<std::string> Files;
  ListFilesInDirRecursive(Path, Epoch, &Files, /*TopDir*/true);
  size_t NumLoaded = 0;
  for (size_t i = 0; i < Files.size(); i++) {
    auto &X = Files[i];
    if (Epoch && GetEpoch(X) < E) continue;
    NumLoaded++;
    if ((NumLoaded & (NumLoaded - 1)) == 0 && NumLoaded >= 1024)
      Printf("Loaded %zd/%zd files from %s\n", NumLoaded, Files.size(), Path);
    V->push_back(FileToVector(X, MaxSize));
  }
}

std::string DirPlusFile(const std::string &DirPath,
                        const std::string &FileName) {
  return DirPath + "/" + FileName;
}

void DupAndCloseStderr() {
  int OutputFd = dup(2);
  if (OutputFd > 0) {
    FILE *NewOutputFile = fdopen(OutputFd, "w");
    if (NewOutputFile) {
      OutputFile = NewOutputFile;
      if (__sanitizer_set_report_fd)
        __sanitizer_set_report_fd(reinterpret_cast<void*>(OutputFd));
      close(2);
    }
  }
}

void CloseStdout() { close(1); }

void Printf(const char *Fmt, ...) {
  va_list ap;
  va_start(ap, Fmt);
  vfprintf(OutputFile, Fmt, ap);
  va_end(ap);
  fflush(OutputFile);
}

}  // namespace fuzzer