UCS/VFS/BASE: convert stack allocation at ucs_vfs_node_add_subdir() t…

…o heap

src/ucs/vfs/base/vfs_obj.c

@@ -223,17 +223,26 @@ static void ucs_vfs_node_build_path(ucs_vfs_node_t *parent_node,
 static ucs_vfs_node_t *
 ucs_vfs_node_add_subdir(ucs_vfs_node_t *parent_node, const char *name)
 {
-    char path_buf[PATH_MAX];
+    char *path_buf = ucs_malloc(PATH_MAX, "path_buf");
     ucs_vfs_node_t *node;
 
-    ucs_vfs_node_build_path(parent_node, name, path_buf, sizeof(path_buf));
+    if (path_buf == NULL) {
+        ucs_error("failed to allocate memory for path_buf");
+        return NULL;
+    }
+
+    ucs_vfs_node_build_path(parent_node, name, path_buf, PATH_MAX);
     node = ucs_vfs_node_find_by_path(path_buf);
     if (node != NULL) {
+        ucs_free(path_buf);
         return node;
     }
 
-    return ucs_vfs_node_create(parent_node, path_buf, UCS_VFS_NODE_TYPE_SUBDIR,
+    node = ucs_vfs_node_create(parent_node, path_buf, UCS_VFS_NODE_TYPE_SUBDIR,
                                NULL);
+    ucs_free(path_buf);
+
+    return node;
 }
 
 static int ucs_vfs_node_need_update_path(ucs_vfs_node_type_t type,