Polish VUS_is() call sites

Motivated by #3864

bin/varnishd/mgt/mgt_acceptor.c

@@ -158,8 +158,7 @@ mk_listen_sock(const struct listen_arg *la, const struct suckaddr *sa)
 	ls->name = la->name;
 	ls->transport = la->transport;
 	ls->perms = la->perms;
-	if (VUS_is(la->endpoint))
-		ls->uds = 1;
+	ls->uds = VUS_is(la->endpoint);
 	VJ_master(JAIL_MASTER_PRIVPORT);
 	fail = mac_opensocket(ls);
 	VJ_master(JAIL_MASTER_LOW);
@@ -368,10 +367,10 @@ MAC_Arg(const char *spec)
 	else
 		AZ(la->perms);
 
-	if (! VUS_is(la->endpoint))
-		error = VSS_resolver(av[1], "80", mac_tcp, la, &err);
-	else
+	if (VUS_is(la->endpoint))
 		error = VUS_resolver(av[1], mac_uds, la, &err);
+	else
+		error = VSS_resolver(av[1], "80", mac_tcp, la, &err);
 
 	if (VTAILQ_EMPTY(&la->socks) || error)
 		ARGV_ERR("Got no socket(s) for %s\n", av[1]);

bin/varnishd/mgt/mgt_main.c

@@ -484,10 +484,10 @@ mgt_b_conv(const char *b_arg)
 	VSB_cat(vsb, "backend default ");
 	if (!strcasecmp(b_arg, "none"))
 		VSB_cat(vsb, "none;\n");
-	else if (! VUS_is(b_arg))
-		VSB_printf(vsb, "{\n    .host = \"%s\";\n}\n", b_arg);
-	else
+	else if (VUS_is(b_arg))
 		VSB_printf(vsb, "{\n    .path = \"%s\";\n}\n", b_arg);
+	else
+		VSB_printf(vsb, "{\n    .host = \"%s\";\n}\n", b_arg);
 	AZ(VSB_finish(vsb));
 	fa->src = strdup(VSB_data(vsb));
 	AN(fa->src);

bin/varnishtest/vtc_server.c

@@ -216,10 +216,10 @@ server_listen(struct server *s)
 
 	if (s->sock >= 0)
 		VTCP_close(&s->sock);
-	if (! VUS_is(s->listen))
-		server_listen_tcp(s, &err);
-	else
+	if (VUS_is(s->listen))
 		server_listen_uds(s, &err);
+	else
+		server_listen_tcp(s, &err);
 	if (err != NULL)
 		vtc_fatal(s->vl,
 		    "Server listen address (%s) cannot be resolved: %s",
@@ -248,11 +248,12 @@ server_conn(void *priv, struct vtclog *vl)
 	fd = accept(s->sock, addr, &l);
 	if (fd < 0)
 		vtc_fatal(vl, "Accept failed: %s", strerror(errno));
-	if (! VUS_is(s->listen)) {
+	if (VUS_is(s->listen))
+		vtc_log(vl, 3, "accepted fd %d 0.0.0.0 0", fd);
+	else {
 		VTCP_hisname(fd, abuf, sizeof abuf, pbuf, sizeof pbuf);
 		vtc_log(vl, 3, "accepted fd %d %s %s", fd, abuf, pbuf);
-	} else
-		vtc_log(vl, 3, "accepted fd %d 0.0.0.0 0", fd);
+	}
 	return (fd);
 }
 
@@ -431,15 +432,15 @@ cmd_server_gen_vcl(struct vsb *vsb)
 		if (s->sock < 0 && s->fd >= 0) /* dispatch instance */
 			continue;
 
-		if (! VUS_is(s->listen))
+		if (VUS_is(s->listen))
+			VSB_printf(vsb,
+				   "backend %s { .path = \"%s\"; }\n",
+				   s->name, s->listen);
+		else
 			VSB_printf(vsb,
 				   "backend %s { .host = \"%s\"; "
 				   ".port = \"%s\"; }\n",
 				   s->name, s->aaddr, s->aport);
-		else
-			VSB_printf(vsb,
-				   "backend %s { .path = \"%s\"; }\n",
-				   s->name, s->listen);
 	}
 	AZ(pthread_mutex_unlock(&server_mtx));
 }