Function to drain controlling tty

tools/tty/tty.go

@@ -315,3 +315,25 @@ func DebugPrintln(a ...any) {
 		term.DebugPrintln(a...)
 	}
 }
+
+func DrainControllingTTY(wait_for time.Duration) {
+	tty, err := OpenControllingTerm(SetRaw, SetNoEcho)
+	if err != nil {
+		return
+	}
+	sel := utils.CreateSelect(1)
+	sel.RegisterRead(tty.Fd())
+	for {
+		n, err := sel.Wait(wait_for)
+		if err == unix.EINTR {
+			continue
+		}
+		if err != nil {
+			return
+		}
+		if n > 0 && sel.IsReadyToRead(tty.Fd()) {
+			tty.Read(make([]byte, 256))
+		}
+		break
+	}
+}