int FsDropInService::processEventLoop()

in src/oomd/dropin/FsDropInService.cpp [300:342]

• 36 lines of code
• 10 McCabe index (conditional complexity)

int FsDropInService::processEventLoop() {
  std::array<struct epoll_event, kMaxEvents> events;

  int n;
  do {
    n = ::epoll_wait(epollfd_, events.data(), kMaxEvents, -1);
  } while (n < 0 && errno == EINTR);
  if (n < 0) {
    OLOG << "epoll_wait: " << Util::strerror_r();
    return 1;
  }

  // This will only contend when drop in dir is recreated and some event fires,
  // which is very rare. See comment above in prepDropInWatcher().
  std::lock_guard<std::mutex> lock(event_loop_mutex_);

  for (int i = 0; i < n; ++i) {
    int fd = events[i].data.fd;
    if (fd == terminatefd_) {
      uint64_t val;
      ssize_t len = ::read(fd, &val, sizeof(val));
      if (len != sizeof(val)) {
        OLOG << "read: " << Util::strerror_r();
        return 1;
      }
      if (val != 1) {
        OLOG << "Unexpected terminatefd value=" << val;
        return 1;
      }
      // Special value for termination
      return 2;
    } else if (fd == inotifyfd_) {
      if (processDropInWatcher(fd)) {
        return 1;
      }
    } else {
      OLOG << "Unknown fd=" << fd << " in event loop";
      return 1;
    }
  }

  return 0;
}