touchup argc/argv handling to shrink a bit and fix a segfault when given wrong number...

diff --git a/networking/ipcalc.c b/networking/ipcalc.c
index bcd272b..c5f2ba1 100644 (file)
--- a/networking/ipcalc.c
+++ b/networking/ipcalc.c
@@ -100,18 +100,19 @@ int ipcalc_main(int argc, char **argv)
                        "mbn"
 #endif
                        );
+
+       argc -= optind;
+       argv += optind;
        if (mode & (BROADCAST | NETWORK | NETPREFIX)) {
-               if (argc - optind > 2) {
+               if (argc > 2 || argc <= 0)
                        bb_show_usage();
-               }
        } else {
-               if (argc - optind != 1) {
+               if (argc != 1)
                        bb_show_usage();
-               }
        }
 
 #ifdef CONFIG_FEATURE_IPCALC_FANCY
-       prefixstr = ipstr = argv[optind];
+       prefixstr = ipstr = argv[0];
 
        while(*prefixstr) {
                if (*prefixstr == '/') {
@@ -142,16 +143,16 @@ int ipcalc_main(int argc, char **argv)
        }
        ipaddr = inet_aton(ipstr, &a);
 #else
-       ipaddr = inet_aton(argv[optind], &a);
+       ipaddr = inet_aton(argv[0], &a);
 #endif
 
        if (ipaddr == 0) {
-               IPCALC_MSG(bb_error_msg_and_die("bad IP address: %s", argv[optind]),
+               IPCALC_MSG(bb_error_msg_and_die("bad IP address: %s", argv[0]),
                                exit(EXIT_FAILURE));
        }
        ipaddr = a.s_addr;
 
-       if (argc - optind == 2) {
+       if (argc == 2) {
 #ifdef CONFIG_FEATURE_IPCALC_FANCY
                if (have_netmask) {
                        IPCALC_MSG(bb_error_msg_and_die("Both prefix and netmask were specified, use one or the other.\n"),
@@ -159,9 +160,9 @@ int ipcalc_main(int argc, char **argv)
                }
 
 #endif
-               netmask = inet_aton(argv[optind + 1], &a);
+               netmask = inet_aton(argv[1], &a);
                if (netmask == 0) {
-                       IPCALC_MSG(bb_error_msg_and_die("bad netmask: %s", argv[optind + 1]),
+                       IPCALC_MSG(bb_error_msg_and_die("bad netmask: %s", argv[1]),
                                        exit(EXIT_FAILURE));
                }
                netmask = a.s_addr;
@@ -200,7 +201,7 @@ int ipcalc_main(int argc, char **argv)
                hostinfo = gethostbyaddr((char *) &ipaddr, sizeof(ipaddr), AF_INET);
                if (!hostinfo) {
                        IPCALC_MSG(bb_herror_msg_and_die(
-                                               "cannot find hostname for %s", argv[optind]),);
+                                               "cannot find hostname for %s", argv[0]),);
                        exit(EXIT_FAILURE);
                }
                for (x = 0; hostinfo->h_name[x]; x++) {