Made some small modifications (backing extraction)

src/container.h

@@ -60,4 +60,10 @@ bool container_filter(const char* file);
 /// @brief Lists the containers in the pool.
 /// @param _containers The string pointer array to store the resulting array in. The caller is responsible for freeing the strings and the array.
 /// @return The result of the operation.
-result_t list_containers(char*** _containers);
+result_t list_containers(char*** _containers);
+
+/// @brief Gets the backing of the given container. If the container does not exist, the call will return a failure result with an error message.
+/// @param _backing The string pointer to store the resulting backing in.
+/// @param container The container to get the backing of.
+/// @return The result of the operation.
+result_t get_container_backing(char** _backing, const char* container);