xioctl and friends by Tito <farmatito@tiscali.it>

function                                             old     new   delta
do_iptunnel                                          203     977    +774
process_dev                                         5328    5494    +166
ioctl_or_perror                                        -      54     +54
ioctl_or_perror_and_die                                -      51     +51
ioctl_alt_func                                         -      49     +49
bb_ioctl_or_warn                                       -      47     +47
do_add_ioctl                                         102     145     +43
bb_xioctl                                              -      39     +39
print_value_on_off                                     -      31     +31
get_lcm                                              105     123     +18
arp_main                                            2155    2167     +12
..................
zcip_main                                           1576    1566     -10
setlogcons_main                                       92      82     -10
dumpkmap_main                                        263     253     -10
do_get_ioctl                                          85      75     -10
setkeycodes_main                                     165     154     -11
write_table                                          244     232     -12
vconfig_main                                         318     306     -12
do_del_ioctl                                          93      81     -12
set_address                                           75      62     -13
maybe_set_utc                                         30      16     -14
loadfont_main                                        495     479     -16
slattach_main                                        712     695     -17
do_loadfont                                          191     174     -17
do_iplink                                           1155    1136     -19
getty_main                                          2583    2562     -21
fbset_main                                          2058    2035     -23
do_time                                              588     565     -23
xioctl                                                25       -     -25
read_rtc                                             186     160     -26
parse_conf                                          1299    1270     -29
udhcp_read_interface                                 269     239     -30
bb_ioctl                                              45       -     -45
bb_ioctl_alt                                          70       -     -70
bb_ioctl_on_off                                       78       -     -78
.rodata                                           129370  129018    -352
do_show                                              799       -    -799
------------------------------------------------------------------------------
(add/remove: 6/5 grow/shrink: 13/49 up/down: 1316/-1864)     Total: -548 bytes
   text	   data	    bss	    dec	    hex	filename
 675352	   2740	  13968	 692060	  a8f5c	busybox_old
 674804	   2740	  13968	 691512	  a8d38	busybox_unstripped

diff --git a/networking/ifconfig.c b/networking/ifconfig.c
index 5e11b2b..0d53676 100644
--- a/networking/ifconfig.c
+++ b/networking/ifconfig.c
@@ -402,12 +402,10 @@
 
 								/* Create a channel to the NET kernel. */
 								sockfd6 = xsocket(AF_INET6, SOCK_DGRAM, 0);
-								if (ioctl(sockfd6, SIOGIFINDEX, &ifr) < 0)
-									bb_perror_msg_and_die("SIOGIFINDEX");
+								xioctl(sockfd6, SIOGIFINDEX, &ifr);
 								ifr6.ifr6_ifindex = ifr.ifr_ifindex;
 								ifr6.ifr6_prefixlen = prefix_len;
-								if (ioctl(sockfd6, a1op->selector, &ifr6) < 0)
-									bb_perror_msg_and_die(a1op->name);
+								ioctl_or_perror_and_die(sockfd6, a1op->selector, &ifr6, "%s", a1op->name);
 								if (ENABLE_FEATURE_CLEAN_UP)
 									free(lsa);
 								continue;
@@ -444,8 +442,7 @@
 					p = ((char *)&ifr) + a1op->ifr_offset;
 #if ENABLE_FEATURE_IFCONFIG_MEMSTART_IOADDR_IRQ
 					if (mask & A_MAP_TYPE) {
-						if (ioctl(sockfd, SIOCGIFMAP, &ifr) < 0)
-							bb_perror_msg_and_die("SIOCGIFMAP");
+						xioctl(sockfd, SIOCGIFMAP, &ifr);
 						if ((mask & A_MAP_UCHAR) == A_MAP_UCHAR)
 							*((unsigned char *) p) = i;
 						else if (mask & A_MAP_USHORT)
@@ -460,8 +457,7 @@
 						*((int *) p) = i;
 				}
 
-				if (ioctl(sockfd, a1op->selector, &ifr) < 0)
-					bb_perror_msg_and_die(a1op->name);
+				ioctl_or_perror_and_die(sockfd, a1op->selector, &ifr, "%s", a1op->name);
 #ifdef QUESTIONABLE_ALIAS_CASE
 				if (mask & A_COLON_CHK) {
 					/*
@@ -486,15 +482,13 @@
 			mask = N_SET;
 		}
 
-		if (ioctl(sockfd, SIOCGIFFLAGS, &ifr) < 0)
-			bb_perror_msg_and_die("SIOCGIFFLAGS");
+		xioctl(sockfd, SIOCGIFFLAGS, &ifr);
 		selector = op->selector;
 		if (mask & SET_MASK)
 			ifr.ifr_flags |= selector;
 		else
 			ifr.ifr_flags &= ~selector;
-		if (ioctl(sockfd, SIOCSIFFLAGS, &ifr) < 0)
-			bb_perror_msg_and_die("SIOCSIFFLAGS");
+		xioctl(sockfd, SIOCSIFFLAGS, &ifr);
 	} /* while () */
 
 	if (ENABLE_FEATURE_CLEAN_UP)