Re: [libvirt] [PATCH] Detailed XML errors when XML is not well-formed

On Wed, Jul 30, 2008 at 03:49:17PM +0100, Richard W.M. Jones wrote: > This patch changes the implementations lots of functions which parse > XML documents, so that if the XML document is not well-formed then we > get detailed error messages. > > The general form of the change is: > > static void > catchXMLError (void *ctx, const char *msg ATTRIBUTE_UNUSED, ...) > { > // a callback which calls virDomainReportError > } > > virDomainDefPtr virDomainDefParseString(virConnectPtr conn, > virCapsPtr caps, > const char *xmlStr) > { > xmlParserCtxtPtr pctxt; > > pctxt = xmlNewParserCtxt (); > pctxt->sax->error = catchXMLError; > > xml = xmlCtxtReadDoc (pctxt, //...) etc. > > There are some unavoidable shortcomings: > > (1) There is no place to stash user pointers during the callback (the > suggestively named pctxt->userData field is already used for something > else), so we cannot pass the virConnectPtr to the error function. As > a result, virterror will store the error in a global variable, and > callers will probably not be able to access it.

> (2) The XML parser routinely produces multiple error messages, and > virterror throws away all but the last one. It'd probably be more use to only report the first one, since the latter problems may well be caused by earlier problems.

You won't see those except with the 'test' or 'xen' drivers run locally. Anything going via the daemon will be output on the daemon's stderr (/dev/null) and not on the client.