From 55e77f964dc30b49c4dede0dd98ddd0761702d43 Mon Sep 17 00:00:00 2001
From: Bjarne von Horn <vh@igh.de>
Date: Tue, 7 Nov 2023 11:44:24 +0100
Subject: [PATCH] Add a nice error message to ethercatctl in case of missing
 config.

---
 script/ethercatctl.in | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/script/ethercatctl.in b/script/ethercatctl.in
index 2da6e95b..ab3f45a8 100755
--- a/script/ethercatctl.in
+++ b/script/ethercatctl.in
@@ -102,6 +102,14 @@ start)
         MASTER_INDEX=$((${MASTER_INDEX} + 1))
     done
 
+    if [ -z "${DEVICES}" ]; then
+        echo "ERROR: No network cards for EtherCAT specified."
+        echo -n "Please edit ${ETHERCAT_CONFIG} with root permissions"
+        echo -n " and set MASTER0_DEVICE variable to either a "
+        echo "network interface name (like eth0) or to a MAC address."
+        exit 1
+    fi
+
     # load master module
     if ! ${MODPROBE} ${MODPROBE_FLAGS} ec_master \
             main_devices="${DEVICES}" backup_devices="${BACKUPS}"; then