Re: [Libvir] [PATCH]Reprt error for a existing file

Kazuki Mizushima wrote: I guess I have a few problems with this patch. Currently only the xend driver actually supports saving domains (remote will support it in the next version too). And it does it by making the path absolute and sending an instruction to xend, so the save is done out of process and is essentially outside the control of libvirt (ie. the behaviour of xend might change in the future). So (IMHO) the questions are: (a) what should the behaviour of virDomainSave be when the file already exists? (b) where should we enforce that behaviour? (c) what behaviours can we support in the underlying drivers? If we accept that virDomainSave should always overwrite the dump file (question (a)), can we support that (question (c) - my reading of the source of libxc is that Xen itself won't overwrite files, but libvirt's xend driver can certainly be modified to delete the file first), and where should we enforce it (question (b) - in libvirt's xend driver). If, on the other hand, we want virDomainSave to never overwrite dump files and core files, then we should probably add a check in the drivers which support the methods (xend and remote) so that they fail under such conditions with a decent error message. My other problem is the use of stat(2) (or access) to determine if a file exists, since we up on slippy ground if this is relied upon in a security-related context. It's better to make the atomic open(2) call fail instead (which is actually what happens in current libxc). Rich.