02 System Description

2. System description

2.1 The two parts

bs-updater has two parts. The parts are independent, but they agree on one configuration file.

Part	Type	Location after the installation
bs-update	POSIX shell script	~/.local/bin/bs-update
The tray widget	KDE Plasma applet	The applet directory of the user

2.2 The bs-update command

bs-update is a POSIX shell script. It does all of the work with the package tools. It has four modes:

Mode	Option	Function
Update	none	Installs the updates of each enabled tool.
List	-l	Counts the available updates of each enabled tool.
Tool list	--list-tools	Shows each supported tool and its state.
Terminal	--in-terminal	Starts a new terminal window and updates in it.

The command reads its selection of tools from a configuration file. The --tools option replaces that selection for one run.

The command is the only part that starts a package tool. The widget never starts a package tool. A run from the widget, a run from the notification and a run from a terminal have one behavior.

2.3 The tray widget

The widget is a KDE Plasma applet in QML. It does these tasks:

1. It starts bs-update -l on a timer and reads the counts.
2. It shows an icon and a tooltip for the update state.
3. It writes the selection of the user to the configuration file.
4. It starts bs-update --in-terminal when the user asks for an update.
5. It installs the bs-update command if the command is absent.

The widget contains its own copy of bs-update. Because of this, an installation of the widget alone from the KDE Store gives a complete product.

2.4 The interface between the parts

The two parts speak through the file system. There is no socket and no D-Bus service.

Direction	Mechanism	Content
Widget to command	~/.config/bs-updater/tools.conf	The selected tools.
Command to widget	Standard output of bs-update -l	The counts.
Command to widget	~/.cache/bs-updater/last-update	The time of the last update run.

Chapter 8 describes each mechanism in detail.

2.5 The supported tools

bs-update drives ten tool entries. Each entry has an identifier, a package domain and a name for the user.

Identifier	Package domain	Name for the user
pacman	repo	pacman
paru-repo	repo	paru, repository packages
paru-aur	aur	paru, AUR packages
dnf	rpm	DNF
nobara-sync	rpm	nobara-sync
nobara-sync-flatpak	flatpak	nobara-sync, Flatpak applications
apt	deb	APT
flatpak	flatpak	Flatpak
gearlever	appimage	Gear Lever
plasmoid-updater	plasmoid	plasmoid-updater

The command runs the enabled tools in this sequence. Chapter 3 describes the package domains and the conflict rule.

2.6 Privileges

bs-updater runs as the user. It does not install a system service, and it does not add a file outside the home directory of the user.

Three tools must have root privileges to install updates:

• pacman and dnf run through sudo;
• apt runs through sudo;
• nobara-sync raises its own privileges, so bs-update does not add sudo to it.

No count operation uses root privileges. This is a design constraint, because a scheduled check has no password. Chapter 8 gives the reason for each count command.