D-Bus: Difference between revisions
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[https://en.wikipedia.org/wiki/D-Bus D-Bus] is a message bus system that provides a mechanism for inter-process communication. | [https://en.wikipedia.org/wiki/D-Bus D-Bus] is a message bus system that provides a mechanism for inter-process communication. | ||
Some services (including | Some services (including [[PipeWire]]) rely on a D-Bus session instance. Other processes will only be able to communicate with these services if d-bus is running. | ||
You can start a dbus session like this: <code>dbus-run-session -- sh</code>(replacing sh with your shell or a window manager), or, <code>export $(dbus-launch)</code>. This is distinct from running dbus system-wide: <code>rc-service dbus start</code>, which is a prerequisite to run a user dbus session. | You can start a dbus session like this: <code>dbus-run-session -- sh</code>(replacing sh with your shell or a window manager), or, <code>export $(dbus-launch)</code>. This is distinct from running dbus system-wide: <code>rc-service dbus start</code>, which is a prerequisite to run a user dbus session. |
Revision as of 18:02, 4 July 2023
D-Bus is a message bus system that provides a mechanism for inter-process communication.
Some services (including PipeWire) rely on a D-Bus session instance. Other processes will only be able to communicate with these services if d-bus is running.
You can start a dbus session like this: dbus-run-session -- sh
(replacing sh with your shell or a window manager), or, export $(dbus-launch)
. This is distinct from running dbus system-wide: rc-service dbus start
, which is a prerequisite to run a user dbus session.
D-Bus passes the environment variable $DBUS_SESSION_BUS_ADDRESS
to its children. Running dbus-launch
in a terminal means that other running process won't find this D-Bus's socket.
If $DBUS_SESSION_BUS_ADDRESS
is undefined, many applications will attempt to use the standard path:
$XDG_RUNTIME_DIR/bus
Running D-Bus like so should work for many applications:
dbus-daemon --nofork --address unix:path=$XDG_RUNTIME_DIR/bus --session
For applications that dont work without $DBUS_SESSION_BUS_ADDRESS
you can prepend your program with the follow workaround script which avoid launching multiple user dbus sessions:
#!/bin/sh if [ ! -e "/tmp/dbus-$USER-env" ]; then echo "Creating new dbus session on /tmp/dbus-$USER-env" export $(dbus-launch) echo "${DBUS_SESSION_BUS_ADDRESS}" > /tmp/dbus-$USER-env echo "Dbus session address is: ${DBUS_SESSION_BUS_ADDRESS}" else echo "Using dbus session address from /tmp/dbus-$USER-env" export DBUS_SESSION_BUS_ADDRESS="$(cat /tmp/dbus-$USER-env)" echo "Dbus session address is: ${DBUS_SESSION_BUS_ADDRESS}" fi if [ -n "$1" ]; then $@ fi