xtables: Add backward compatibility with -w option

Just to keep aligned with iptables legacy tool.

Signed-off-by: Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
diff --git a/iptables/nft.h b/iptables/nft.h
index 26b60b9..22af66e 100644
--- a/iptables/nft.h
+++ b/iptables/nft.h
@@ -135,7 +135,7 @@
 const char *nft_strerror(int err);
 
 /* For xtables.c */
-int do_commandx(struct nft_handle *h, int argc, char *argv[], char **table);
+int do_commandx(struct nft_handle *h, int argc, char *argv[], char **table, bool restore);
 /* For xtables-arptables.c */
 int do_commandarp(struct nft_handle *h, int argc, char *argv[], char **table);
 
diff --git a/iptables/xtables-restore.c b/iptables/xtables-restore.c
index c4af2c5..730800f 100644
--- a/iptables/xtables-restore.c
+++ b/iptables/xtables-restore.c
@@ -442,7 +442,8 @@
 			for (a = 0; a < newargc; a++)
 				DEBUGP("argv[%u]: %s\n", a, newargv[a]);
 
-			ret = do_commandx(&h, newargc, newargv, &newargv[2]);
+			ret = do_commandx(&h, newargc, newargv,
+					  &newargv[2], true);
 			if (ret < 0) {
 				ret = nft_abort(&h);
 				if (ret < 0) {
diff --git a/iptables/xtables-standalone.c b/iptables/xtables-standalone.c
index eb13980..355a446 100644
--- a/iptables/xtables-standalone.c
+++ b/iptables/xtables-standalone.c
@@ -70,7 +70,7 @@
 		exit(EXIT_FAILURE);
 	}
 
-	ret = do_commandx(&h, argc, argv, &table);
+	ret = do_commandx(&h, argc, argv, &table, false);
 	if (ret)
 		ret = nft_commit(&h);
 
diff --git a/iptables/xtables.c b/iptables/xtables.c
index c49b4a2..7a8ace3 100644
--- a/iptables/xtables.c
+++ b/iptables/xtables.c
@@ -678,7 +678,8 @@
 		xtables_error(OTHER_PROBLEM, "can't alloc memory!");
 }
 
-int do_commandx(struct nft_handle *h, int argc, char *argv[], char **table)
+int do_commandx(struct nft_handle *h, int argc, char *argv[], char **table,
+		bool restore)
 {
 	struct iptables_command_state cs;
 	int verbose = 0;
@@ -1001,6 +1002,14 @@
 				       prog_name, prog_vers);
 			exit(0);
 
+		case 'w':
+			if (restore) {
+				xtables_error(PARAMETER_PROBLEM,
+					      "You cannot use `-w' from "
+					      "iptables-restore");
+			}
+			break;
+
 		case '0':
 			set_option(&cs.options, OPT_LINENUMBERS,
 				   &args.invflags, cs.invert);