common: Only use an existing session bus

As soon as there is a dbus user session a session bus should be
available. Only verify that this exists (failling if it doesn't) rather
then trying to workaround things by autolaunching a new bus.

Reviewed-by: Luis Araujo <luis.araujo@collabora.co.uk>
Signed-off-by: Sjoerd Simons <sjoerd.simons@collabora.co.uk>
Differential Revision: https://phabricator.apertis.org/D3663

common/common.sh

@@ -155,41 +155,16 @@ arch_is_arm() {
     [[ $(uname -m) =~ arm.* ]]
 }
 
-# Try hard to find an existing dbus session bus that can be used by the current
-# user, and if none exists, autolaunch one.
-# Also, set XDG_RUNTIME_DIR
+# Check if a session bus is running otherwise fail
 ensure_dbus_session() {
-    local dbus_socket dbus_vars
-    if [[ -z $DBUS_SESSION_BUS_ADDRESS ]]; then
-        whine "DBUS_SESSION_BUS_ADDRESS is unset!"
-        # Check if we have a systemd-managed dbus session bus. Here, a user can
-        # only access its own session bus, so we can only check this path.
-        dbus_socket="/run/user/$UID/bus"
-        if [[ -e ${dbus_socket} ]]; then
-            export DBUS_SESSION_BUS_ADDRESS="unix:path=${dbus_socket}"
-            say "Set DBUS_SESSION_BUS_ADDRESS='$DBUS_SESSION_BUS_ADDRESS', continuing"
-        else
-            # Maybe we're in SDK, and using a traditional dbus-launch session
-            # bus which can be detected using DISPLAY
-            if [[ -z $DISPLAY ]]; then
-                whine "No X DISPLAY found to get dbus user session! Trying :0"
-                export DISPLAY=":0"
-            fi
-            # Use dbus-launch to find an existing session on DISPLAY, and
-            # if it doesn't exist, autolaunch one connected to DISPLAY.
-            dbus_vars=($(dbus-launch --autolaunch $(<"/etc/machine-id")))
-            if echo "${dbus_vars[0]}" | grep -q "DBUS_SESSION_BUS_ADDRESS"; then
-                export "${dbus_vars[0]}"
-                say "Set DBUS_SESSION_BUS_ADDRESS='$DBUS_SESSION_BUS_ADDRESS', continuing"
-            else
-                cry "Unable to ensure a dbus session! Aborting ..."
-                return 1
-            fi
-        fi
+    local dbus_socket
+
+    dbus_socket="/run/user/$UID/bus"
+    if [[ ! -e {dbus_socket} ]]; then
+        cry "Could not find session bus..."
+        return 1
     fi
 
-    # This doesn't get set properly by su/PAM on a serial console
-    export XDG_RUNTIME_DIR="/run/user/$UID"
     return 0
 }