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

[Martin Kletzander]

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.

>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;
>
>
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