From: Sven Eckelmann <sven@narfation.org>
Date: Mon, 15 Feb 2021 19:56:22 +0100
Subject: alfred: Show error message for invalid batadv interface

The alfred server process always stopped without any informational message
when the provided batman-adv was not "none" and was not accessible. This
made it extremely hard to debug the reason why alfred directly stopped
after launching it.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Forwarded: https://patchwork.open-mesh.org/project/b.a.t.m.a.n./patch/20210215200126.140253-1-sven@narfation.org/

diff --git a/server.c b/server.c
index fc27246b845af75bd1f459f8bb553aef87cc24d5..efac5ad399df52f8c444711a14bcf4814e38a3bf 100644
--- a/server.c
+++ b/server.c
@@ -385,8 +385,11 @@ int alfred_server(struct globals *globals)
 	}
 
 	if (strcmp(globals->mesh_iface, "none") != 0 &&
-	    batadv_interface_check(globals->mesh_iface) < 0)
+	    batadv_interface_check(globals->mesh_iface) < 0) {
+		fprintf(stderr, "Can't start server: batman-adv interface %s not found\n",
+			globals->mesh_iface);
 		return -1;
+	}
 
 	num_socks = netsock_open_all(globals);
 	if (num_socks <= 0) {