Re: [xml] xmlNodeDumpOutputInternal segfault when usingt '/' as xpath expr

[Daniel Veillard <veillard redhat com>]

On Mon, Jul 05, 2004 at 08:36:43AM -0700, Joel McConaughy wrote:
> I get the following segfault when using '/' as an xpath expression:
>
>    Program received signal SIGSEGV, Segmentation fault.
>    [Switching to Thread 1024 (LWP 6946)]
>    0x400d5cb8 in xmlNodeDumpOutputInternal (ctxt=0xbffff640, cur=0x804d438)
>        at xmlsave.c:737
>    737        if ((cur->ns != NULL) && (cur->ns->prefix != NULL)) {
>
> I have modified the xpath2.c sample to dump the results of an xpath 
> expression using xmlNodeDumpOutput.  The problem can be reproduced by 

  xpath2.c is used to modify the target nodes to change their value.
if You do that on / you would modify the Document Root node. This won't
work.

[...]
> The only change I made to the sample was to replace update_xpath_nodes() 
> with get_xpath_nodes().  The code is pretty simple and I can't see any 
> problems however pilot error is always a possibility.  Help would be 
> greatly appreciated.  Thanks.

  there is no get_xpath_nodes() in xpath2.c . 
Using "/" as an XPath expression is used all the time, especially in XSLT
on top of libxml2. I don't see this being an xpath error. It likely to be
an error handling the XML_DOCUMENT_NODE nore returned from the query.
Never assume that a node is of a given type before processing it. Always
test node->type first.

Daniel

-- 
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veillard redhat com  | libxml GNOME XML XSLT toolkit  http://xmlsoft.org/
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