#28807 [Opn->Csd]: Apache 2 child segfaults on request after script with xinclude
ID: 28807
User updated by: rmolier at more-it dot com
Reported By: rmolier at more-it dot com
-Status: Open
+Status: Closed
Bug Type: DOM XML related
Operating System: Fedora Core 1+2 / RHEL AS 3
PHP Version: 4.3.6/4.3.2/4.3.4
New Comment:
Finally (after two weeks of reinstalling, building etc.) I found a
simple workaround which works in my case.
1. XSLT->process($Doc,null,null,null,true);
This is to create a copy of the XSLT document in order to replace the
nodes without problems. A case of RTFM. (or in this case, Find A Bug
That Seems Similar, and no there is no acronym for that yet... Any
suggestions?)
2. Replace the call-template in xslt by copy-of.
In XSLT processing I did not need to generate handmade copies of the
element, and now use <xsl:copy-of select="*"/> in stead of the nice
call-template. This to stay away from some internal XSLT problems. This
problem wasn't solved by the first step though. A case of KISS, nothing
more nothing less.
If this doesn't help for you, I guess you'll have to start crying
toward the developer of libxslt who most likely will be (partly)
responsible for the mess you are in.
Previous Comments:
------------------------------------------------------------------------
[2004-06-16 21:19:04] rmolier at more-it dot com
The segfault doesn't occur however...
------------------------------------------------------------------------
[2004-06-16 21:16:12] rmolier at more-it dot com
Even more funny:
It seems that only in the case the element was created in the
stylesheet function (which is basically a remove parent element from
list function) the memory leak occurs. Without the XMLInclude this
resulted in one extra free invalid pointer message().
I tested this by adding an additional element to the main document in
the following way:
/* code: begin */
$XMLIncludeElement = $XMLDom->create_element("include");
$XMLIncludedElement = $XMLDom->create_element("gettext");
$XMLIncludedElementText = $XMLDom->create_text_node("Text included in
main document");
$XMLIncludedElement->append_child($XMLIncludedElementText);
$XMLIncludeElement->append_child($XMLIncludedElement);
$XMLDocument->append_child($XMLIncludeElement);
/*code: end */
------------------------------------------------------------------------
[2004-06-16 20:48:26] rmolier at more-it dot com
With option 3 (DOM XML / XInclude /XSLT) I get after the third time:
Allowed memory size of 8388608 bytes exhausted (tried to allocate 10
bytes) and the process dies with 01.
------------------------------------------------------------------------
[2004-06-16 20:37:41] rmolier at more-it dot com
I found a way to reproduce the same behaviour in a simple script. I did
the following tests myself by commenting out some code:
1. DOM + XInclude + XSLT + Replacenode = problem
2. DOM + XInclude + Replacenode = no problem
3. DOM + XInclude + XSLT = no problem
4. DOM + XInclude = no problem
5. DOM + XSLT + Replacenode = no problem
6. DOM + Replacenode = no problem
For the people that would like to reproduce the bug I have created the
following script:
/* xmltest.php: begin */
<?php
echo "Starting Document<br>";
$XMLDom = domxml_new_doc("1.0");
$XMLDocument = $XMLDom->create_element("document");
$XMLDom->append_child($XMLDocument);
$XMLElement = $XMLDom->create_element("replace");
$XMLElementText = $XMLDom->create_text_node("replace this text");
$XMLElement->append_child($XMLElementText);
$XMLDocument->append_child($XMLElement);
$XMLInclude =
$XMLDom->create_element_ns("http://www.w3.org/2001/XInclude","include","xi");
$XMLInclude->set_attribute("href","include.xml");
$XMLDocument->append_child($XMLInclude);
echo "<pre>";
echo htmlentities($XMLDom->dump_mem(true));
echo "</pre>";
$XMLDom->xinclude();
echo "After Include<br>";
echo "<pre>";
echo htmlentities($XMLDom->dump_mem(true));
echo "</pre>";
$XSLTStylesheet = domxml_xslt_stylesheet_file("stylesheet.xslt");
$XSLTResult = $XSLTStylesheet->process($XMLDom);
echo "After Stylesheet<br>";
echo "<pre>";
echo htmlentities($XSLTResult->dump_mem(true));
echo "</pre>";
$XPathContext = xpath_new_context($XSLTResult);
$XPathResult = xpath_eval($XPathContext,"//gettext");
echo "<pre>";
print_r($XPathResult);
echo "</pre>";
foreach ($XPathResult->nodeset as $XPathNode)
{
$XMLParentNode = $XPathNode->parent_node();
$XMLElementText = $XPathNode->first_child();
$Text = $XMLElementText->get_content();
$XMLTextNode = $XSLTResult->create_text_node($Text);
$XPathNode->replace_node($XMLTextNode);
}
echo "After Replace<br>";
echo "<pre>";
echo htmlentities($XSLTResult->dump_mem(true));
echo "</pre>";
?>
/* xmltest: end */
/* include.xml: begin */
<?xml version="1.0" encoding="UTF-8" ?>
<include>
<gettext>This is the included replace</gettext>
</include>
/* include.xml: end */
/* stylesheet.xslt */
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" version="1.0" encoding="UTF-8"
indent="yes"/>
<xsl:template match="/">
<document>
<xsl:apply-templates/>
</document>
</xsl:template>
<xsl:template match="replace">
<gettext>
<xsl:value-of select="."/>
</gettext>
</xsl:template>
<xsl:template name="display-element">
<xsl:element name="{name()}">
<xsl:for-each select="@*">
<xsl:attribute name="{name()}">
<xsl:value-of select="."/>
</xsl:attribute>
</xsl:for-each>
<xsl:choose>
<xsl:when test="count(*) !=0">
<xsl:for-each select="*">
<xsl:call-template name="display-element"/>
</xsl:for-each>
</xsl:when>
<xsl:otherwise>
<xsl:value-of select="."/>
</xsl:otherwise>
</xsl:choose>
</xsl:element>
</xsl:template>
<xsl:template match="include">
<xsl:for-each select="*">
<xsl:call-template name="display-element"/>
</xsl:for-each>
</xsl:template>
</xsl:stylesheet>
/* stylesheet.xslt */
------------------------------------------------------------------------
[2004-06-16 19:06:58] rmolier at more-it dot com
To clarify a little on the magical number of 17. It seems, that after
performing the xinclude I perform exactly 17 node replaces on the
included nodes..
Think that the problem can be found somewhere there.....
Flow for reproducing:
Create a document from scratch.
Add a number of xinclude statements.
Perform an Xinclude
Perform an XSLT transformation.
Perform an Xpath query on the document.
Replace the resulting nodes with text nodes.
------------------------------------------------------------------------
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