Method ueventProcessUEvent

src/Library/UMockdevDeviceManager.cpp:628–721

  }

  void UMockdevDeviceManager::ueventProcessUEvent(const UEvent& uevent)
  {
    const std::string subsystem = uevent.getAttribute("SUBSYSTEM");
    const std::string devtype = uevent.getAttribute("DEVTYPE");
    const std::string action = uevent.getAttribute("ACTION");

    /*
     * We don't care about the event if it's not from the "usb" subsystem.
     * The device type attribute value is checked later based on the data
     * read from the sysfs uevent file in the device directory.
     */
    if (subsystem != "usb") {
      USBGUARD_LOG(Debug) << "Ignoring non-USB device:"
        << " subsystem=" << subsystem
        << " devtype=" << devtype
        << " action=" << action;
      return;
    }

    const std::string sysfs_devpath = uevent.getAttribute("DEVPATH");
    bool enumeration_notify = false;

    try {
      std::unique_lock<std::mutex> lock(_enumeration_mutex);
      uint32_t id = 0;
      const bool known_path = knownSysfsPath(sysfs_devpath, &id);

      if (action == "add" || action == "change") {
        lock.unlock();
        USBGUARD_LOG(Debug) << "known_path=" << known_path << " id=" << id;

        if (known_path && id > 0) {
          processDevicePresence(id);
        }
        else {
          SysFSDevice sysfs_device(sysfs_devpath);

          /*
           * Do some additional sanity checking.
           */
          if (sysfs_device.getUEvent().hasAttribute("DEVTYPE")) {
            const std::string devtype = sysfs_device.getUEvent().getAttribute("DEVTYPE");

            if (devtype != "usb_device") {
              USBGUARD_LOG(Debug) << sysfs_devpath << ": UEvent DEVTYPE != usb_device. Ignoring event.";
              return;
            }
          }
          else {
            if (!sysfs_device.hasAttribute("descriptors")) {
              USBGUARD_LOG(Debug) << sysfs_devpath << ": UEvent doesn't refer to a device with a descriptors file. Ignoring event.";
              return;
            }
          }

          processDeviceInsertion(sysfs_device, /*signal_present=*/known_path);
          USBGUARD_LOG(Debug) << "Enumeration notify: sysfs_devpath=" << sysfs_devpath
            << " _enumeration=" << _enumeration