[libvirt] [PATCH] fix some XPath relative node resets

[Laine Stump]

On 09/28/2009 11:30 AM, Daniel Veillard wrote:
>   The virXPath... function take extra care to preserve the XPath context
> node (ctxt->node) but in the case of virXPathString and virXPathBoolean
> they forgot to do this on the error path. This patch fixes this and
> move all ctxt->node = relnode instuctions just after the xmlXPathEval()
> to make sure this doesn't happen if this code is modified.
>    

Daniel,

I tried this patch with my tree, and it didn't change the behavior - in 
virInterfaceDefParseProtoIPv4 if I find a dhcp node with

     dhcp = virXPathNode(conn, "./dhcp", ctxt);

any ip node will not be found with a subsequent

         ip = virXPathNode(conn, "./ip", ctxt);

(if dhcp comes back null, the ip node *is* found).

However, if I first make the call to look for the ip node, and then do 
the call for the dhcp node, both are found. Does that provide any clue 
to you?


Also, you'll notice a new bit of code in virInterfaceDefParseIp:

         tmp = virXPathString(conn, "string(./ip[1]/@source)", ctxt);

For some reason, tmp always comes back null, even if my ip node looks 
like the one in the example below:

<interface type="ethernet" name="wlan0">
<start mode="none"/>
<mac address="00:1f:3c:9d:87:7c"/>
<protocol family="ipv4">
<dhcp/>
<ip address="10.24.0.101" prefix="24" source="device"/>
</protocol>
</interface>