-- called by /home/master/builder/bin/slave-build-connect
SELECT `build_slaves`.`id`, `persons`.`name` FROM `build_slaves` JOIN `ssh_keys` ON `build_slaves`.`ssh_key`=`ssh_keys`.`id` JOIN `persons` ON `ssh_keys`.`owner`=`persons`.`id` WHERE `build_slaves`.`name`=from_base64("ZXVyb251Yy1pNDg2") AND `build_slaves`.`access_allowed`;