traceroute: Gateway selection.

ChangeLog

@@ -1,3 +1,13 @@
+2013-07-04  Mats Erik Andersson  <gnu@gisladisker.se>
+
+	traceroute: Gateway selection.
+	Make `-g' additive in repeated use to better
+	conform with other implementations.
+
+	* src/traceroute.c (parse_opt) [IP_OPTIONS] <'g'>:
+	Append `arg' to `opt_gateways' if the latter has
+	already been assigned a value.
+
 2013-06-28  Mats Erik Andersson  <gnu@gisladisker.se>
 
 	traceroute: Portability of PID range.

doc/inetutils.texi

@@ -1060,6 +1060,7 @@ using spaces, commata, or semicola as separators.
 These hosts must be traversed in the given order
 before the intended host receives any datagram.
 At most eight host names or addresses may be specified.
+Multiple uses of @option{-g} produce a concatenated list.
 
 @item -I
 @itemx --icmp

src/traceroute.c

@@ -179,7 +179,22 @@ parse_opt (int key, char *arg, struct argp_state *state)
 
 #ifdef IP_OPTIONS
     case 'g':
-      opt_gateways = xstrdup (arg);
+      if (opt_gateways)
+	{
+	  size_t len = 0;
+
+	  len = strlen (opt_gateways);
+	  opt_gateways = xrealloc (opt_gateways, len + strlen (arg) + 3);
+
+	  /* Append new gateways to old list,
+	   * separating the two parts by a comma.
+	   */
+	  opt_gateways[len] = ',';
+	  opt_gateways[len + 1] = '\0';
+	  strcat (opt_gateways, arg);
+	}
+      else
+	opt_gateways = xstrdup (arg);
       break;
 #endif /* IP_OPTIONS */