--- tcpdump-3.4/print-ether.c.jbj	Tue Aug  3 19:45:06 1999
+++ tcpdump-3.4/print-ether.c	Wed Aug  4 09:08:36 1999
@@ -54,6 +54,7 @@
 #include <linux/if_packet.h>
 
 #include <stdio.h>
+#include <ctype.h>
 #include <pcap.h>
 
 #include "interface.h"
@@ -103,20 +104,23 @@
 		static char ifnames[16][16];
 		if (h->ifindex>0 && h->ifindex <= 16) {
 			if (ifnames[h->ifindex-1][0] == 0) {
-				int tmp_fd;
+				int tmp_fd, err;
 				struct ifreq ifr;
 				ifr.ifr_ifindex = h->ifindex;
 				tmp_fd = socket(AF_INET, SOCK_DGRAM, 0);
-				if (ioctl(tmp_fd, SIOCGIFNAME, (char*)&ifr) == 0) {
+				err = ioctl(tmp_fd, SIOCGIFNAME, (char*)&ifr);
+			/* XXX SIOCGIFNAME fubar on sparc64 2.2.10-3 */
+				if (err == 0 &&
+				    (isprint(ifr.ifr_name[0]) && isprint(ifr.ifr_name[1]))) {
 					memcpy(ifnames[h->ifindex-1], ifr.ifr_name, 16);
 				} else {
-					sprintf(ifnames[h->ifindex-1], "if%2d ", h->ifindex);
+					sprintf(ifnames[h->ifindex-1], "if%02d ", h->ifindex);
 				}
 				close(tmp_fd);
 			}
 			printf("%4s ", ifnames[h->ifindex-1]);
 		} else
-			printf("if%2d ", h->ifindex);
+			printf("if%02d ", h->ifindex);
 	}
 
 	switch (h->pkt_type) {