def _dnsmasq_pid_for(dev):
    """Returns the pid for prior dnsmasq instance for a bridge/device.

    Returns None if no pid file exists.

    If machine has rebooted pid might be incorrect (caller should check).

    """
    pid_file = _dhcp_file(dev, 'pid')

    if os.path.exists(pid_file):
        try:
            with open(pid_file, 'r') as f:
                return int(f.read())
        except (ValueError, __HOLE__):
            return None
dataset/ETHPy150Open openstack/nova/nova/network/linux_net.py/_dnsmasq_pid_for