[libvirt] [PATCH v2] virsh: add [--domain DOMAIN] option to domxml-to-native DOMAIN COMMAND

[Dan]

On Fri, Jun 02, 2017 at 11:33:50AM +0200, Martin Kletzander wrote:
> On Fri, Jun 02, 2017 at 05:18:52AM -0400, Dan wrote:
> > On Tue, May 30, 2017 at 08:45:37AM +0200, Peter Krempa wrote:
> > > On Mon, May 29, 2017 at 14:08:53 -0400, Daniel Liu wrote:
> > > > The option allows someone to run domain-to-native on already existing
> > > >  domain without the need of supplying their XML.  It is basically
> > > >  wrapper around 'virsh dumpxml  | virsh domxml-to-native /dev/stdin'.
> > > > Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=835476
> > > > ---
> > > >  tools/virsh-domain.c | 52 ++++++++++++++++++++++++++++++++++++++++------------
> > > >  1 file changed, 40 insertions(+), 12 deletions(-)
> > > >
> > > > diff --git a/tools/virsh-domain.c b/tools/virsh-domain.c
> > > > index ccb514ef9..929f9c896 100644
> > > > --- a/tools/virsh-domain.c
> > > > +++ b/tools/virsh-domain.c
> > > 
> > > [...]
> > > 
> > > > @@ -9859,30 +9863,54 @@ static const vshCmdOptDef opts_domxmltonative[] = {
> > > >  static bool
> > > >  cmdDomXMLToNative(vshControl *ctl, const vshCmd *cmd)
> > > >  {
> > > > -    bool ret = true;
> > > > +    bool ret = false;
> > > >      const char *format = NULL;
> > > > -    const char *xmlFile = NULL;
> > > > -    char *configData;
> > > > -    char *xmlData;
> > > > +    const char *domain = NULL;
> > > > +    const char *xml = NULL;
> > > > +    char *xmlData = NULL;
> > > > +    char *configData = NULL;
> > > >      unsigned int flags = 0;
> > > >      virshControlPtr priv = ctl->privData;
> > > > +    virDomainPtr dom = NULL;
> > > >
> > > >      if (vshCommandOptStringReq(ctl, cmd, "format", &format) < 0 ||
> > > > -        vshCommandOptStringReq(ctl, cmd, "xml", &xmlFile) < 0)
> > > > +        vshCommandOptStringReq(ctl, cmd, "xml", &xml) < 0 ||
> > > > +        vshCommandOptStringReq(ctl, cmd, "domain", &domain) < 0)
> > > 
> > > You don't need this variable after the check below, so it's pointless to
> > > extract it.
> > > 
> > > >          return false;
> > > >
> > > > -    if (virFileReadAll(xmlFile, VSH_MAX_XML_FILE, &xmlData) < 0)
> > > > +    VSH_EXCLUSIVE_OPTIONS_VAR(domain, xml);
> > > 
> > > This macro is documented to work only on booleans, please don't use it
> > > on pointers.
> > > 
> > > > +
> > > > +    if (domain) {
> > > > +        if (!(dom = virshCommandOptDomain(ctl, cmd, NULL)))
> > > > +            return false;
> > > > +    }
> > > > +
> > > > +    if (dom) {
> > > > +        xmlData = virDomainGetXMLDesc(dom, flags);
> > > > +    } else if (xml) {
> > > > +        if (virFileReadAll(xml, VSH_MAX_XML_FILE, &xmlData) < 0)
> > > > +            goto cleanup;
> > > > +    }
> > > > +
> > > > +    if (!xmlData) {
> > > > +        vshError(ctl, "%s",
> > > > +                 _("need either domain (ID, UUID, or name) or domain XML configuration file path"));
> > > 
> > > This line is very long.
> > > 
> > > >          return false;
> > > 
> > > You'll leak 'dom' here if it was looked up, but getting of the XML
> > > failed.
> > > 
> > > Also the message is kind of wrong in that case, since you've provided a
> > > valid name, but the XML could not be requested
> > > 
> > > > +    }
> > > >
> > > > -    configData = virConnectDomainXMLToNative(priv->conn, format, xmlData, flags);
> > > > -    if (configData != NULL) {
> > > > -        vshPrint(ctl, "%s", configData);
> > > > -        VIR_FREE(configData);
> > > > +    if (!(configData = virConnectDomainXMLToNative(priv->conn, format, xmlData, flags))) {
> > > > +        vshError(ctl, "%s",
> > > > +                 _("convert from domain XML to native command failed"));
> > > 
> > > For 'xen' the output is not really a command, so this message also is
> > > not very good.
> > > 
> > I found out it is actually XM config files from the domxml-to-native
> > command
> > https://libvirt.org/drvxen.html#xmlexport
> > 
> > So for v4 of this patch, I am going to delete the "command" word, i.e.:
> >        vshError(ctl, "%s", _("convert from domain XML to native failed"));
> > 
> 
> That sentence doesn't make sense.  "Conversion from domain XML to native
> representation failed" would make more sense, but I don't know why you
> are complicating it for yourself.  There was no vshError() before your
> patch and I don't see why it would be needed.
> 
Hey Martin,

Finally, I deleted the error message print statement in patch v4.

Cheers,

Dan
> > some test cases when this error happened:
> > 
> > 
> > $ virsh -c qemu:///system domxml-to-native qemu-argv dl_dumpxml170529.xml
> > error: convert from domain XML to native command failed
> > error: (domain_definition):111: expected '>'
> > </domain>
> > -------^
> > 
> > $ echo $?
> > 1
> > $ virsh -c qemu:///system domxml-to-native qemu-argv dl_test_dumpxml.xml
> > error: convert from domain XML to native command failed
> > error: invalid argument: could not find capabilities for arch=i686 domaintype=test
> > 
> > Btw, for the first error, the erroneous part of my test xml was actually
> > the first line of a domain xml dump; I deleted the character 'n' in
> > 'domain' string:
> > 
> > <domai type='kvm' id='1'>
> >  <name>ubuntu1404</name>
> >  <uuid>e8742104-ecac-2ed9-a9d6-e1x15319374f</uuid>
> > 
> > i.e., the error message did not detect the true invalidity of
> > the xml file. But this is not a big issue, right?
> > 
> 
> Well, it actually did:
> 
>  error: (domain_definition):111: expected '>'
> 
> This is the error from libxml2 forwarded through libvirt.
> 
> > P.S. Is there anything more I need to change for this PATCH?
> > 
> > Thanks,
> > 
> > Dan
> > > >      } else {
> > > > -        ret = false;
> > > > +        vshPrint(ctl, "%s", configData);
> > > > +        ret = true;
> > 
> >