--- ../mii_mgr.c.bak	2022-11-03 15:21:40.446210000 +0800
+++ ../mii_mgr.c	2022-11-03 15:23:20.435803359 +0800
@@ -118,7 +118,7 @@
 				is_priv = 0;
 				break;
 			case 'i':
-				strncpy(ifname, optarg, 5);
+				strncpy(ifname, optarg, IFNAMSIZ);
 				ifname[IFNAMSIZ - 1] = '\0';
 				break;	
 			case 'p':