Use Xlib code to find a keyboard instead of relying on user config

cmd/after-lock/after-lock.go

@@ -1,12 +1,14 @@
 package main
 
 import (
+	"errors"
 	"kdelsd/afterlock"
 	"kdelsd/config"
 	"kdelsd/lockfile"
 	"kdelsd/xdg/display"
 	"kdelsd/xdg/keypressdetector"
 	"kdelsd/xdg/lockscreen"
+	"kdelsd/xdg/xinput_devnodes"
 	"log"
 	"os"
 	"os/signal"
@@ -18,7 +20,6 @@ import (
 type afterLockConfig struct {
 	INITIAL_DELAY int
 	LOOP_DELAY int
-	DEV_NODE string
 	LOCK_PATH string
 	LOG_PATH string
 	PRINT_STACKTRACES bool
@@ -99,11 +100,19 @@ func initCleanup(lock *lockfile.Lockfile, logfile *os.File) {
 }
 
 func buildAfterlock() *afterlock.AfterLock {
-	al := afterlock.New(configuration.DEV_NODE)
+	al := afterlock.New(getKeyboardDevNode())
 	al.InitialDelay = uint(configuration.INITIAL_DELAY)
 	al.LoopDelay = uint(configuration.LOOP_DELAY)
 	al.Display = display.Xset{}
 	al.LockScreen = lockscreen.XDG{}
 	al.KeypressDetector = keypressdetector.Evdev{}
 	return al
-}
+}
+
+func getKeyboardDevNode() string {
+	devNode := xinput_devnodes.FindKeyboardDevNode()
+	if devNode == "" {
+		panic(errors.New("unable to find keyboard device node"))
+	}
+	return devNode
+}