knsupdate: don't pre-set the zone to root

doc/man/knsupdate.1in

@@ -93,12 +93,12 @@ address and port are set by the system automatically. The default port number
 is 0.
 .TP
 \fBzone\fP \fIname\fP
-Specifies that all updates are done within a zone \fIname\fP\&. If not specified,
-the root zone (\fB\&.\fP) is considered.
+Specifies that all updates are done within a zone \fIname\fP\&. The zone name doesn\(aqt
+have a default and must be set explicitly.
 .TP
 \fBorigin\fP \fIname\fP
 Specifies fully qualified domain name suffix which is appended to non\-fqd
-owners in update commands. The default origin is the root zone.
+owners in update commands. The default is the terminal label (\fB\&.\fP).
 .TP
 \fBclass\fP \fIname\fP
 Sets \fIname\fP as the default class for all updates. If not used, the default

doc/man_knsupdate.rst

@@ -70,12 +70,12 @@ Commands
   is 0.
 
 **zone** *name*
-  Specifies that all updates are done within a zone *name*. If not specified,
-  the root zone (**.**) is considered.
+  Specifies that all updates are done within a zone *name*. The zone name doesn't
+  have a default and must be set explicitly.
 
 **origin** *name*
   Specifies fully qualified domain name suffix which is appended to non-fqd
-  owners in update commands. The default origin is the root zone.
+  owners in update commands. The default is the terminal label (**.**).
 
 **class** *name*
   Sets *name* as the default class for all updates. If not used, the default

src/utils/knsupdate/knsupdate_exec.c

@@ -810,6 +810,11 @@ int cmd_send(const char* lp, knsupdate_params_t *params)
 	DBG("%s: lp='%s'\n", __func__, lp);
 	DBG("sending packet\n");
 
+	if (params->zone == NULL) {
+		ERR("no zone specified\n");
+		return KNOT_EINVAL;
+	}
+
 	/* Build query packet. */
 	int ret = build_query(params);
 	if (ret != KNOT_EOK) {

src/utils/knsupdate/knsupdate_params.c

@@ -104,7 +104,6 @@ static int knsupdate_init(knsupdate_params_t *params)
 	params->class_num = KNOT_CLASS_IN;
 	params->retries = DEFAULT_RETRIES_NSUPDATE;
 	params->wait = DEFAULT_TIMEOUT_NSUPDATE;
-	params->zone = strdup(".");
 
 	/* Initialize RR parser. */
 	if (zs_init(&params->parser, ".", params->class_num, 3600) != 0 ||