[libvirt] [PATCHv2 13/7] snapshot: implement snapshot children listing in vbox

[Matthias Bolte]

2011/10/4 Eric Blake <eblake at redhat.com>:
> Adding this for VBox was a bit harder than for ESX, but the same
> principles apply for starting the traversal at a known point
> rather than covering the entire hierarchy.
>
> * src/vbox/vbox_tmpl.c (vboxCountDescendants)
> (vboxDomainSnapshotNumChildren)
> (vboxDomainSnapshotListChildrenNames): New functions.
> ---
>
> Caveat: Again, only compile-tested.  No idea if it really works.
> It copies a good chunk of code from vboxDomainSnapshotGetAll, but
> I didn't really see a clean way to factor that repeated chunk into
> its own function.
>
>  src/vbox/vbox_tmpl.c |  208 ++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 files changed, 208 insertions(+), 0 deletions(-)
>
> diff --git a/src/vbox/vbox_tmpl.c b/src/vbox/vbox_tmpl.c
> index d1da6fd..a5372e8 100644
> --- a/src/vbox/vbox_tmpl.c
> +++ b/src/vbox/vbox_tmpl.c

> +static int
> +vboxDomainSnapshotListChildrenNames(virDomainSnapshotPtr snapshot,
> +                                    char **names,
> +                                    int nameslen,
> +                                    unsigned int flags)

> +    if (flags & VIR_DOMAIN_SNAPSHOT_LIST_DESCENDANTS) {
> +        int top = children.count;
> +        int next;
> +
> +        for (next = 0; next < count; next++) {
> +            if (!snapshots[next])
> +                break;

This line is wrong I think. In vboxDomainSnapshotGetAll this works,
because list[0] is pre-filled with the root, but here it's initially
NULL and the whole loop is directly left.

> +            rc = vboxArrayGet(&children, snapshots[next],
> +                              snapshots[next]->vtbl->GetChildren);
> +            if (NS_FAILED(rc)) {
> +                vboxError(VIR_ERR_INTERNAL_ERROR,
> +                          "%s", _("could not get children snapshots"));
> +                goto cleanup;
> +            }
> +            for (i = 0; i < children.count; i++) {
> +                ISnapshot *child = children.items[i];
> +                if (!child)
> +                    continue;
> +                if (top == count) {
> +                    vboxError(VIR_ERR_INTERNAL_ERROR,
> +                              _("unexpected number of snapshots > %u"), count);
> +                    vboxArrayRelease(&children);
> +                    goto cleanup;
> +                }
> +                VBOX_ADDREF(child);
> +                snapshots[top++] = child;
> +            }
> +            vboxArrayRelease(&children);
> +        }
> +        count = top;
> +    } else {
> +        count = children.count;
> +    }
> +
> +    for (i = 0; i < nameslen; i++) {
> +        PRUnichar *nameUtf16;
> +        char *name;
> +
> +        if (i >= count)
> +            break;
> +
> +        rc = snapshots[i]->vtbl->GetName(snapshots[i], &nameUtf16);

This triggers a segfault, because snapshots[0] is NULL.

I ran out of time for debugging this.

-- 
Matthias Bolte
http://photron.blogspot.com