Mainly 4 parts:
- scripts for providing rpmdb and yum repos to VM (choosen by qvm-set-updatevm)
- VM script for downloading updates (qubes_download_dom0_updates.sh)
- qfile-dom0-unpacker which receive updates, check signatures and place its in dom0 local yum repo
- qvm-dom0-upgrade which calls all of above and after all yum gpk-update-viewer
Besides qvm-dom0-upgrade, updates are checked every 6h and user is prompted if
want to download it. At dom0 side gpk-update-icon (disabled yet) should notice
new updates in "local" repo.