[libvirt] [PATCH 5/7] conf: spice: Do more automation if autoport is requested

[Daniel P. Berrange]

On Tue, Apr 23, 2013 at 08:57:10PM +0200, Peter Krempa wrote:
> On 04/23/13 18:21, Daniel P. Berrange wrote:
> >On Tue, Apr 23, 2013 at 03:46:12PM +0200, Peter Krempa wrote:
> >>With autoport enabled, both ports were alocated. With enabling
> >>defaultMode or setting separate channel modes one of the ports may not
> >>be needed. This will allow later on doing this kind of change.
> >>---
> >>  docs/formatdomain.html.in | 2 +-
> >>  src/conf/domain_conf.c    | 5 -----
> >>  2 files changed, 1 insertion(+), 6 deletions(-)
> >>
> >>diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in
> >>index 888c005..bb75943 100644
> >>--- a/docs/formatdomain.html.in
> >>+++ b/docs/formatdomain.html.in
> >>@@ -3470,7 +3470,7 @@ qemu-kvm -net nic,model=? /dev/null
> >>                while <code>tlsPort</code> gives an alternative secure
> >>                port number. The <code>autoport</code> attribute is the
> >>                new preferred syntax for indicating autoallocation of
> >>-              both port numbers.  The <code>listen</code> attribute is
> >>+              needed port numbers.  The <code>listen</code> attribute is
> >>                an IP address for the server to listen
> >>                on. The <code>passwd</code> attribute provides a SPICE
> >>                password in clear text. The <code>keymap</code>
> >>diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
> >>index dc0ecaa..86a444c 100644
> >>--- a/src/conf/domain_conf.c
> >>+++ b/src/conf/domain_conf.c
> >>@@ -7595,11 +7595,6 @@ virDomainGraphicsDefParseXML(xmlNodePtr node,
> >>              VIR_FREE(defaultMode);
> >>          }
> >>
> >>-        if (def->data.spice.port == -1 && def->data.spice.tlsPort == -1) {
> >>-            /* Legacy compat syntax, used -1 for auto-port */
> >>-            def->data.spice.autoport = true;
> >>-        }
> >
> >I'm not clear why this is safe. The idea is that if the user sends XML
> >
> >    <graphics port='-1' tlsPort='-1'/>
> >
> >then libvirt would turn it into
> >
> >    <graphics port='-1' tlsPort='-1' autoport='yes'/>
> >
> >with this removed, won't we be instead outputting
> >
> >    <graphics port='-1' tlsPort='-1' autoport='no'/>
> >
> >despite the fact that it is auto-allocating the ports?
> 
> Later on this will slightly change semantics:
> 
> <graphics port='-1' tlsPort='-1' autoport='no'/>
> 
> Will allocate both ports every time, even if one isn't needed
> because of other configuration (eg defaultMode="insecure")

That is certainly not right. 

If we're allocating ports then we *must* be setting autoport='yes'.
Having port='1' and tlsPort='-1' and autoport='no' is a non-sensical
configuration.

> whereas
> 
> <graphics autoport='yes'/>
> 
> will automatically determine which ports are needed according to
> configuration and allocate just those. (only the insecure port in
> case of the example above)

Daniel
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