[libvirt] [PATCH 6/4] virsh: add virsh snapshot-current --name

[Eric Blake]

On 08/09/2011 09:13 PM, Eric Blake wrote:
> Sometimes, full XML is too much; since most snapshot commands
> operate on a snapshot name, there should be an easy way to get
> at the current snapshot's name.
>
> * tools/virsh.c (cmdSnapshotCurrent): Add an option.
> * tools/virsh.pod (snapshot-current): Document it.
> ---
>   tools/virsh.c   |   21 ++++++++++++++++++---
>   tools/virsh.pod |    4 +++-
>   2 files changed, 21 insertions(+), 4 deletions(-)
>

> @@ -12065,13 +12067,26 @@ cmdSnapshotCurrent(vshControl *ctl, const vshCmd *cmd)
>           if (!xml)
>               goto cleanup;
>
> -        vshPrint(ctl, "%s", xml);
> -        VIR_FREE(xml);
> +        if (vshCommandOptBool(cmd, "name")) {
> +            char *tmp;
> +
> +            name = strstr(xml, "<name>");
> +            if (!name)
> +                goto cleanup;
> +            name += strlen("<name>");
> +            tmp = strstr(name, "</name>");

Admittedly, this mishandles any XML escapes, such as '<', occurring 
in name.  A more robust solution involves introducing a new 
virDomainSnapshotGetName; however, while that is a good idea, it goes 
counter to my goal of no new API for my first round of disk-only 
snapshot support.  Then again, I'm thinking that even with a new API, 
virsh should be smart enough to use the new API where it works, and fall 
back to the xml scraping where it doesn't, so I'm debating whether this 
needs to switch to full-blown xpath parsing instead of just strstr scraping.

-- 
Eric Blake   eblake at redhat.com    +1-801-349-2682
Libvirt virtualization library http://libvirt.org