static void

pack_extract(const char *pack, const char *dbname, const char *dbpath)

{

	struct archive *a = NULL;

	struct archive_entry *ae = NULL;

	if (access(pack, F_OK) != 0)

		return;

	a = archive_read_new();

	archive_read_support_filter_all(a);

	archive_read_support_format_tar(a);

	if (archive_read_open_filename(a, pack, 4096) != ARCHIVE_OK) {

		/* if we can't unpack it it won't be useful for us */

		unlink(pack);

		archive_read_free(a);

		return;

	}

	while (archive_read_next_header(a, &ae) == ARCHIVE_OK) {

		if (strcmp(archive_entry_pathname(ae), dbname) == 0) {

			archive_entry_set_pathname(ae, dbpath);

			archive_read_extract(a, ae, EXTRACT_ARCHIVE_FLAGS);

			break;

		}

	}

	archive_read_free(a);

}