static void MSLExternalSubset(void *context,const xmlChar *name,
  const xmlChar *external_id,const xmlChar *system_id)
{
  MSLInfo
    *msl_info;

  xmlParserCtxt
    parser_context;

  xmlParserCtxtPtr
    parser;

  xmlParserInputPtr
    input;

  /*
    Does this document has an external subset?
  */
  (void) LogMagickEvent(CoderEvent,GetMagickModule(),
    "  SAX.externalSubset(%s %s %s)",name,
    (external_id != (const xmlChar *) NULL ? (const char *) external_id : " "),
    (system_id != (const xmlChar *) NULL ? (const char *) system_id : " "));
  msl_info=(MSLInfo *) context;
  (void) msl_info;
  parser=msl_info->parser;
  if (((external_id == NULL) && (system_id == NULL)) ||
      ((parser->validate == 0) || (parser->wellFormed == 0) ||
      (msl_info->document == 0)))
    return;
  input=MSLResolveEntity(context,external_id,system_id);
  if (input == NULL)
    return;
  (void) xmlNewDtd(msl_info->document,name,external_id,system_id);
  parser_context=(*parser);
  parser->inputTab=(xmlParserInputPtr *) xmlMalloc(5*sizeof(*parser->inputTab));
  if (parser->inputTab == (xmlParserInputPtr *) NULL)
    {
      parser->errNo=XML_ERR_NO_MEMORY;
      parser->input=parser_context.input;
      parser->inputNr=parser_context.inputNr;
      parser->inputMax=parser_context.inputMax;
      parser->inputTab=parser_context.inputTab;
      return;
  }
  parser->inputNr=0;
  parser->inputMax=5;
  parser->input=NULL;
  xmlPushInput(parser,input);
  (void) xmlSwitchEncoding(parser,xmlDetectCharEncoding(parser->input->cur,4));
  if (input->filename == (char *) NULL)
    input->filename=(char *) xmlStrdup(system_id);
  input->line=1;
  input->col=1;
  input->base=parser->input->cur;
  input->cur=parser->input->cur;
  input->free=NULL;
  xmlParseExternalSubset(parser,external_id,system_id);
  while (parser->inputNr > 1)
    (void) xmlPopInput(parser);
  xmlFreeInputStream(parser->input);
  xmlFree(parser->inputTab);
  parser->input=parser_context.input;
  parser->inputNr=parser_context.inputNr;
  parser->inputMax=parser_context.inputMax;
  parser->inputTab=parser_context.inputTab;
}

The product does not release a resource after its effective lifetime has ended, i.e., after the resource is no longer needed.