D-Bus

D-Bus is a message bus system that provides an easy way for inter-process communication. It consists of a daemon, which can be run both system-wide and for each user session, and a set of libraries to allow applications to use D-Bus.

dbus is pulled and installed as a dependency of systemd and user session bus is started automatically for each user.

Alternative Implementations

dbus-broker

dbus-broker is a drop-in replacement for the libdbus reference implementation, which aims "to provide high performance and reliability, while keeping compatibility to the D-Bus reference implementation". [1]

To enable dbus-broker as the system bus:

# systemctl enable dbus-broker.service

To enable as a user bus, run as the desired user:

$ systemctl --user enable dbus-broker.service

Or, to enable for all users, run as root:

# systemctl --global enable dbus-broker.service

Reboot for these settings to take effect.

Debugging

• D-Feet — Easy to use D-Bus debugger GUI tool. D-Feet can be used to inspect D-Bus interfaces of running programs and invoke methods on those interfaces.

https://wiki.gnome.org/Apps/DFeet || d-feet

• QDbusViewer — GUI D-Bus debugger. Can be used to inspect D-Bus services and invoke methods on them.

https://doc.qt.io/qt-5/qdbusviewer.html || qt5-tools

You can also use busctl(5)^{[dead link 2019-08-19]} from systemd.

See also

• D-Bus homepage – freedesktop.org
• Introduction to D-Bus – freedesktop.org