prologProcessor(XML_Parser parser, const char *s, const char *end,
                const char **nextPtr) {
  const char *next = s;
  int tok = XmlPrologTok(parser->m_encoding, s, end, &next);
  return doProlog(parser, parser->m_encoding, s, end, tok, next, nextPtr,
                  (XML_Bool)! parser->m_parsingStatus.finalBuffer);
}
The software uses XML documents and allows their structure to be defined with a Document Type Definition (DTD), but it does not properly control the number of recursive definitions of entities.