[libvirt] [PATCH 3/3] libvirt-domain: virConnectListDomains: Return 0 on zero-size buffer
Daniel P. Berrangé
berrange at redhat.com
Mon Nov 18 13:04:01 UTC 2019
On Mon, Nov 18, 2019 at 01:18:19PM +0100, Erik Skultety wrote:
> It doesn't make sense to pass a target buffer into an API, declaring its
> size as 0 and expect some meaningful result. Since this used to work
> pre-Glib era, we shouldn't end with an error, but we can return 0
> for the number of domains immediately, instead of calling into the
> daemon, which is exactly what the daemon would have returned anyway.
Passing in size as 0 is going to be normal practice, given the calling
convention of this API design.
> Signed-off-by: Erik Skultety <eskultet at redhat.com>
> src/libvirt-domain.c | 3 +++
> 1 file changed, 3 insertions(+)
> diff --git a/src/libvirt-domain.c b/src/libvirt-domain.c
> index 02622cb2ca..0def40fdf7 100644
> --- a/src/libvirt-domain.c
> +++ b/src/libvirt-domain.c
> @@ -62,6 +62,9 @@ virConnectListDomains(virConnectPtr conn, int *ids, int maxids)
> virCheckNonNullArgGoto(ids, error);
> virCheckNonNegativeArgGoto(maxids, error);
> + if (maxids == 0)
> + return 0;
This is too late really, as we alrady checked 'ids'.
IMHO, we should only mandate a non-NULL 'ids' parameter when
maxids > 0 a few lines earlier
All the other legacy APIs share the same validation flaw so will
also need fixing.
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