Tom Lane escribió:
> We might be able to compromise by only resetting the context after
> an error, but this is still only possible if we have a way to make
> libxml let go of *all* pointers to alloc'd objects. I don't understand
> your comment that xmlCleanupParser solves it --- we call that already,
> and it doesn't seem to be preventing the problem.
With the attached patch, it doesn't crash, but I see the added WARNING
four times in the log, which is proof that the cleanup thing is not
called as the code seems to think.
I wonder -- is this thing supposed to be reentrant? I think that's the
whole problem with it.
(I think what I'm doing in xml_init in the non-first case is bogus
anyway -- but I post the patch to show my point.)
--
Alvaro Herrera http://www.CommandPrompt.com/
PostgreSQL Replication, Consulting, Custom Development, 24x7 support
Index: src/backend/utils/adt/xml.c
===================================================================
RCS file: /home/alvherre/Code/cvs/pgsql/src/backend/utils/adt/xml.c,v
retrieving revision 1.64
diff -c -p -r1.64 xml.c
*** src/backend/utils/adt/xml.c 1 Jan 2008 19:45:53 -0000 1.64
--- src/backend/utils/adt/xml.c 10 Jan 2008 00:37:32 -0000
*************** XmlOptionType xmloption;
*** 80,85 ****
--- 80,86 ----
#ifdef USE_LIBXML
static StringInfo xml_err_buf = NULL;
+ static MemoryContext LibxmlContext = NULL;
static void xml_init(void);
static void *xml_palloc(size_t size);
*************** xmlvalidate(PG_FUNCTION_ARGS)
*** 844,849 ****
--- 845,852 ----
xmlFreeParserCtxt(ctxt);
ctxt = NULL;
xmlCleanupParser();
+ MemoryContextDelete(LibxmlContext);
+ LibxmlContext = NULL;
}
PG_CATCH();
{
*************** xmlvalidate(PG_FUNCTION_ARGS)
*** 858,863 ****
--- 861,868 ----
if (ctxt)
xmlFreeParserCtxt(ctxt);
xmlCleanupParser();
+ MemoryContextDelete(LibxmlContext);
+ LibxmlContext = NULL;
PG_RE_THROW();
}
*************** xml_init(void)
*** 953,958 ****
--- 958,969 ----
xmlSetGenericErrorFunc(NULL, xml_errorHandler);
/* Set up memory allocation our way, too */
+ Assert(LibxmlContext == NULL);
+ LibxmlContext = AllocSetContextCreate(PortalContext,
+ "LibxmlContext",
+ ALLOCSET_DEFAULT_MINSIZE,
+ ALLOCSET_DEFAULT_INITSIZE,
+ ALLOCSET_DEFAULT_MAXSIZE);
xmlMemSetup(xml_pfree, xml_palloc, xml_repalloc, xml_pstrdup);
/* Check library compatibility */
*************** xml_init(void)
*** 974,979 ****
--- 985,998 ----
* about, anyway.
*/
xmlSetGenericErrorFunc(NULL, xml_errorHandler);
+ if (LibxmlContext == NULL)
+ LibxmlContext = AllocSetContextCreate(PortalContext,
+ "LibxmlContext",
+ ALLOCSET_DEFAULT_MINSIZE,
+ ALLOCSET_DEFAULT_INITSIZE,
+ ALLOCSET_DEFAULT_MAXSIZE);
+ else
+ elog(WARNING, "LibxmlContext already exists");
xmlMemSetup(xml_pfree, xml_palloc, xml_repalloc, xml_pstrdup);
}
}
*************** xml_parse(text *data, XmlOptionType xmlo
*** 1285,1290 ****
--- 1304,1311 ----
xmlFreeParserCtxt(ctxt);
ctxt = NULL;
xmlCleanupParser();
+ MemoryContextDelete(LibxmlContext);
+ LibxmlContext = NULL;
}
PG_CATCH();
{
*************** xml_parse(text *data, XmlOptionType xmlo
*** 1293,1298 ****
--- 1314,1321 ----
if (ctxt)
xmlFreeParserCtxt(ctxt);
xmlCleanupParser();
+ MemoryContextDelete(LibxmlContext);
+ LibxmlContext = NULL;
PG_RE_THROW();
}
*************** xml_text2xmlChar(text *in)
*** 1325,1331 ****
static void *
xml_palloc(size_t size)
{
! return palloc(size);
}
--- 1348,1354 ----
static void *
xml_palloc(size_t size)
{
! return MemoryContextAlloc(LibxmlContext, size);
}
*************** xml_pfree(void *ptr)
*** 1346,1352 ****
static char *
xml_pstrdup(const char *string)
{
! return pstrdup(string);
}
--- 1369,1375 ----
static char *
xml_pstrdup(const char *string)
{
! return MemoryContextStrdup(LibxmlContext, string);
}
*************** xpath(PG_FUNCTION_ARGS)
*** 3368,3374 ****
"could not parse XML data");
xpathctx = xmlXPathNewContext(doc);
if (xpathctx == NULL)
! xml_ereport(ERROR, ERRCODE_INTERNAL_ERROR,
"could not allocate XPath context");
xpathctx->node = xmlDocGetRootElement(doc);
if (xpathctx->node == NULL)
--- 3391,3397 ----
"could not parse XML data");
xpathctx = xmlXPathNewContext(doc);
if (xpathctx == NULL)
! xml_ereport(ERROR, ERRCODE_OUT_OF_MEMORY,
"could not allocate XPath context");
xpathctx->node = xmlDocGetRootElement(doc);
if (xpathctx->node == NULL)
*************** xpath(PG_FUNCTION_ARGS)
*** 3439,3444 ****
--- 3462,3469 ----
xmlFreeParserCtxt(ctxt);
ctxt = NULL;
xmlCleanupParser();
+ MemoryContextDelete(LibxmlContext);
+ LibxmlContext = NULL;
}
PG_CATCH();
{
*************** xpath(PG_FUNCTION_ARGS)
*** 3453,3458 ****
--- 3478,3485 ----
if (ctxt)
xmlFreeParserCtxt(ctxt);
xmlCleanupParser();
+ MemoryContextDelete(LibxmlContext);
+ LibxmlContext = NULL;
PG_RE_THROW();
}
---------------------------(end of broadcast)---------------------------
TIP 4: Have you searched our list archives?
http://archives.postgresql.org
