ensures that Exim has exclusive use of the database before it even tries to
open it. If there is a database, there should be a lock file in existence. */
-sprintf(CS buffer, "%s/db/%s.lockfile", spool_directory, name);
+sprintf(CS buffer, "%s/db/%.200s.lockfile", spool_directory, name);
dbblock->lockfd = Uopen(buffer, flags, 0);
if (dbblock->lockfd < 0)