Re: [xml] another of those fun SEGV's in xmlFreeDoc?

[Daniel Veillard <veillard redhat com>]

On Thu, Oct 27, 2005 at 09:49:39AM -0700, Rick Jones wrote:
> Daniel Veillard wrote:
> > On Thu, Oct 27, 2005 at 09:14:15AM -0700, Rick Jones wrote:
> >
> > > if ((*message = xmlParseMemory(message_base,message_len)) != NULL) {
> >
> >
> >
> >  Hum, okay , could try to use xmlReadMemory and check if problem persists
>
> What sematic differences are there?  Does xlmReadMemory do validation and 
> attribute loading from the DTD (more that I left-out originally, sorry - 
> i'm not the only one "contributing" to this code and they went down a path 
> of getting default values from a DTD)

  no. It's the new parser API, the one using SAX2 parser and not the old one.

> > > fromnid = xmlGetProp(msg,(const xmlChar *)"fromnid");
> >
> >
> >  seems fromnid value ain't checked and the returned string is leaked as
> > not xmlFree'd
>
> IIRC, the messages pass-through validation, so if there isn't a fromnid, I 
> _think_ xmlParseMemory will have failed?

  Validation is not a fatal error. You still get a document on a non valid
instance.

> >   I can't guess what this does to doc or cur.
> >   Do you still get the problem if you skip that step ?
>
> Yeah, I was wondering about that as I was doing the cut-and-paste.  I'll go 
> digging through to see what that routine might be doing...

> >  yeah, this should not hang
> >
> >  Did you tried to run your app under valgrind. I can't see anything wrong 
> > which would lead to the problem
>
> I have no idea what valgrind is, so nope :)

then it's really time you stop anything else and learn about it. Seriously
it spots memory use error, is present in all Linux distros and works by
reinterpreting instructions (so slow but extremely accurate and thorough)

   http://valgrind.org/

it will spot for example the unfreed attribute value.

Daniel

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