fix: handle NULL from json_tokener_new_ex

if there is not enough memory to fit json_tokener and (depth *
json_tokener_srec) in RAM, don't segfault.

swaymsg/main.c

@@ -482,6 +482,10 @@ int main(int argc, char **argv) {
 
 	// pretty print the json
 	json_tokener *tok = json_tokener_new_ex(INT_MAX);
+	if (tok == NULL) {
+		sway_log(SWAY_ERROR, "failed allocating json_tokener");
+		ret = 1;
+	} else {
 		json_object *obj = json_tokener_parse_ex(tok, resp, -1);
 		enum json_tokener_error err = json_tokener_get_error(tok);
 		json_tokener_free(tok);
@@ -505,6 +509,7 @@ int main(int argc, char **argv) {
 			}
 			json_object_put(obj);
 		}
+	}
 	free(command);
 	free(resp);
 
@@ -521,6 +526,11 @@ int main(int argc, char **argv) {
 			}
 
 			json_tokener *tok = json_tokener_new_ex(INT_MAX);
+			if (tok == NULL) {
+				sway_log(SWAY_ERROR, "failed allocating json_tokener");
+				ret = 1;
+				break;
+			}
 			json_object *obj = json_tokener_parse_ex(tok, reply->payload, -1);
 			enum json_tokener_error err = json_tokener_get_error(tok);
 			json_tokener_free(tok);