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

[Daniel P. Berrange]

On Mon, Mar 05, 2007 at 06:04:49PM +0900, Kazuki Mizushima wrote:
> Hi, 
> 
> I make a patch which reports error for a existing file to prevent 
> overwriting before the file.

> diff -u -p -r1.58 virsh.c
> --- src/virsh.c 2 Mar 2007 14:22:33 -0000       1.58
> +++ src/virsh.c 5 Mar 2007 06:49:28 -0000
> @@ -871,6 +873,11 @@ cmdSave(vshControl * ctl, vshCmd * cmd)
>     if (!(dom = vshCommandOptDomain(ctl, cmd, "domain", &name)))
>         return FALSE;
> 
> +    if (stat(to, &st) == 0){
> +        vshError(ctl, FALSE, _("file %s exists already"), to);
> +        return FALSE;
> +    }
> +

This isn't going to work if virsh is talking to a remote hypervisor.
It also assumes that virsh can read the directory where the image
is being saved, which isn't neccessarily true. The directory may 
very well only be readable by XenD itself so putting in an explicit
overwrite check is just giving a false sense of security to users.
There is really no way virsh/libvirt can reliably check for dump
or save file existance - only XenD or QEMU can do that. So if we want
these kind of policy checks they should be put into the XenD or QEMU
as appropriate.

Regards,
Dan.
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