[xml] memory leakages when parsing

["Volker Roth" <pulken gmx net>]

Hello,
we find memory leakages in the following situation:

An xml-File references an Entity defined in the DTD
The File is parsed by
   xmlReadFile(pFilename, NULL,
      XML_PARSE_DTDVALID |
      XML_PARSE_NOENT |
      XML_PARSE_DTDLOAD |
      XML_PARSE_DTDATTR);

After freeing the xmlDocPtr and clearing the xmlParser,
=====================================================================
=================< the report from MSVCPP(W2K) is:
> =========================
=====================================================================
   Detected memory leaks!
   Dumping objects ->
   {226} normal block at 0x0031E448, 8 bytes long.
    Data: <nbktext > 6E 62 6B 74 65 78 74 00
   {225} normal block at 0x0031A030, 8 bytes long.
    Data: <nbktext > 6E 62 6B 74 65 78 74 00
   Object dump complete.

=====================================================================
=========< Output from Valgrind on Libxmlversion 2.6.14:
> =========================
=====================================================================
==22765== 144 bytes in 18 blocks are definitely lost in loss record 3 of 4
==22765==    at 0x1B902E20: malloc (in
/usr/lib/valgrind/vgpreload_memcheck.so)
==22765==    by 0x1B9A7F31: xmlStrndup (xmlstring.c:45)
==22765==    by 0x1B9A7FC1: xmlStrdup (xmlstring.c:71)
==22765==    by 0x1B94C160: xmlParseReference (parser.c:5596)


=====================================================================
====================< Comment >======================================
=====================================================================

The leakage is confirmed by valgrind on linux too,
libxml-Versions are 2.6.7 and 2.6.14.
Moreover, it does not vanish, when we work explicitely with a parsercontext.

How can the leakage be avoided?


=====================================================================
====================< DTD >==========================================
=====================================================================

<?xml version="1.0" encoding="ISO-8859-1" ?>

<!ELEMENT rnode (f)>

<!ELEMENT f (#PCDATA)>
<!ATTLIST f
   att1 CDATA #FIXED 'J'>

<!ENTITY f
   "
   <f>
   hello world
   </f>
   "
>

=====================================================================
====================< XML >==========================================
=====================================================================

<?xml version="1.0" encoding="ISO-8859-1" ?>
<!DOCTYPE rnode SYSTEM "hallowelt.dtd">

<rnode>
   &f;
</rnode>


=====================================================================
====================< Source >=======================================
=====================================================================

#include <CRTDBG.H>

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <libxml/parser.h>
#include <libxml/tree.h>

void DebInit(void)
{
   int tmpFlag = _CrtSetDbgFlag( _CRTDBG_REPORT_FLAG );

   tmpFlag |= _CRTDBG_LEAK_CHECK_DF;
   tmpFlag |= _CRTDBG_ALLOC_MEM_DF; /* Turn on debug allocation */
   tmpFlag |= _CRTDBG_CHECK_ALWAYS_DF; /* Check heap every alloc/dealloc */
   tmpFlag |= _CRTDBG_LEAK_CHECK_DF; /* Leak check at program exit */

   _CrtSetDbgFlag( tmpFlag );
}

xmlDocPtr schablone_GetSchabloneFilename(const char* pFilename);

xmlDocPtr schablone_GetSchabloneFilename(const char* pFilename)
{
   xmlDocPtr        pSchablone = NULL;

   pSchablone = xmlReadFile(pFilename, NULL, XML_PARSE_DTDVALID |
                                             XML_PARSE_NOENT |
                                             XML_PARSE_DTDLOAD |
                                             XML_PARSE_DTDATTR);

   if (pSchablone == NULL)
   {
      return NULL;
   }
   return pSchablone;

}

int main(int argc, char *argv[])
{
   xmlDocPtr    pDomOut       = NULL;

   DebInit();

   pDomOut = schablone_GetSchabloneFilename("C:\\hallowelt.xml");

   xmlFreeDoc(pDomOut),

   xmlCleanupParser();

   printf("main ende\n");
   return 0;
}

thanks in advance
Volker Roth