	void initialize(const string &path, bool owner) {
		TRACE_POINT();
		this->path  = path;
		this->owner = owner;
		
		/* Create the server instance directory. We only need to write to this
		 * directory for these reasons:
		 * 1. Initial population of structure files (structure_version.txt, instance.pid).
		 * 2. Creating/removing a generation directory.
		 * 3. Removing the entire server instance directory (after all
		 *    generations are removed).
		 *
		 * 1 and 2 are done by the helper server during initialization and before lowering
		 * privilege. 3 is done during helper server shutdown by a cleanup process that's
		 * running as the same user the helper server was running as before privilege
		 * lowering.
		 * Therefore, we make the directory only writable by the user the helper server
		 * was running as before privilege is lowered. Everybody else has read and execute
		 * rights though, because we want admin tools to be able to list the available
		 * generations no matter what user they're running as.
		 */
		if (owner) {
			switch (getFileType(path)) {
			case FT_NONEXISTANT:
				createDirectory(path);
				break;
			case FT_DIRECTORY:
				removeDirTree(path);
				createDirectory(path);
				break;
			default:
				throw RuntimeException("'" + path + "' already exists, and is not a directory");
			}
		} else if (getFileType(path) != FT_DIRECTORY) {
			throw RuntimeException("Server instance directory '" + path +
				"' does not exist");
		}
	}
The software attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.