Re: [libvirt-users] Does libvirt have API to detect image format

On 08/11/2014 02:35 PM, Jianfeng Tang wrote: >> > > I am using backing store when I create my volume. However, the backing > store file is from another team, which can be either in raw or in qcow2 > format. > > Is there a libvirt API to detect image format by given an image file? >Or I > have to run qemu-img? virStorageVolGetXMLDesc() in the C code ('virsh vol-dumpxml' from the command line), if your volume resides within a storage pool. Furthermore, if there is ANY possibility that the file might be raw but that the volume has been in use by a possibly malicious guest, you CANNOT blindly trust a file probe that says qcow2, because a guest can write header information into a raw disk in order to make probes return qcow2. So take the output with a grain of salt (it is safe to blindly trust a claim of 'raw', but blindly trusting a claim of 'qcow2' is risky if you don't know the history behind the image). -- Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org