Function __syscall_getdents64

system/lib/wasmfs/syscalls.cpp:909–974

}

int __syscall_getdents64(int fd, void* dirp, size_t count) {
  dirent* result = (dirent*)dirp;

  // Check if the result buffer is too small.
  if (count / sizeof(dirent) == 0) {
    return -EINVAL;
  }

  auto openFile = wasmFS.getFileTable().locked().getEntry(fd);
  if (!openFile) {
    return -EBADF;
  }
  auto lockedOpenFile = openFile->locked();

  auto dir = lockedOpenFile.getFile()->dynCast<Directory>();
  if (!dir) {
    return -ENOTDIR;
  }
  auto lockedDir = dir->locked();

  // A directory's position corresponds to the index in its entries vector.
  int index = lockedOpenFile.getPosition();

  // If this directory has been unlinked and has no parent, then it is
  // completely empty.
  auto parent = lockedDir.getParent();
  if (!parent) {
    return 0;
  }

  off_t bytesRead = 0;
  const auto& dirents = openFile->dirents;
  for (; index < dirents.size() && bytesRead + sizeof(dirent) <= count;
       index++) {
    const auto& entry = dirents[index];
    result->d_ino = entry.ino;
    result->d_off = index + 1;
    result->d_reclen = sizeof(dirent);
    switch (entry.kind) {
      case File::UnknownKind:
        result->d_type = DT_UNKNOWN;
        break;
      case File::DataFileKind:
        result->d_type = DT_REG;
        break;
      case File::DirectoryKind:
        result->d_type = DT_DIR;
        break;
      case File::SymlinkKind:
        result->d_type = DT_LNK;
        break;
      default:
        result->d_type = DT_UNKNOWN;
        break;
    }
    assert(entry.name.size() + 1 <= sizeof(result->d_name));
    strcpy(result->d_name, entry.name.c_str());
    ++result;