Fix bug preventing input after the first startup of the container

Xorg was starting before udev could finish the monitor command. This prevented the X server from having access to the input devices. For some reason, any subsequent starts would be fine.

Adding a small delay to the X server start and triggering a request for device events from the kernel after a delay seems to fix this issue.

overlay/usr/bin/start-udev.sh

@@ -12,30 +12,28 @@
 # CATCH TERM SIGNAL:
 _term() {
     kill -TERM "$monitor_pid" 2>/dev/null
-    kill -TERM "$trigger_pid" 2>/dev/null
-    kill -TERM "$udevd_pid" 2>/dev/null
 }
-trap _term SIGTERM
+trap _term SIGTERM SIGINT
 
 
 # EXECUTE PROCESS:
+# Remove lockfile
+rm -f /tmp/.udev-started
 # Start udev
-# Source: https://github.com/balena-io-playground/balena-base-images/
 if command -v udevd &>/dev/null; then
     unshare --net udevd --daemon &>/dev/null
-    udevd_pid=$!
 else
     unshare --net /lib/systemd/systemd-udevd --daemon &>/dev/null
-    udevd_pid=$!
 fi
-udevadm trigger &>/dev/null
-trigger_pid=$!
 # Monitor kernel uevents
 udevadm monitor &
 monitor_pid=$!
-
+# Touch lockfile
+sleep 1
+touch /tmp/.udev-started
+# Wait for 10 seconds, then request device events from the kernel
+sleep 10
+udevadm trigger
 
 # WAIT FOR CHILD PROCESS:
 wait "$monitor_pid"
-wait "$trigger_pid"
-wait "$udevd_pid"