[libvirt] [PATCH] Add basic support for VDI images

[Daniel P. Berrange]

On Mon, Feb 04, 2013 at 06:53:34PM +0100, Martin Kletzander wrote:
> On 02/04/2013 04:53 PM, Daniel P. Berrange wrote:
> > On Mon, Feb 04, 2013 at 04:46:53PM +0100, Martin Kletzander wrote:
> [...]
> >> +
> >> +    /* not fully supported, but qemu knows it, so we should be able to
> >> +     * handle this at least basically */
> >> +    [VIR_STORAGE_FILE_VDI] = { NULL, ".vdi", LV_LITTLE_ENDIAN,
> >> +                               -2, 0, 0, 0, 0, -1, NULL},
> > 
> > We can do better than that - look at block/vdi.c in QEMU GIT tree
> > to find out the offsets / values for version number, magic signature
> > at least, even if you ignore backing files for now.
> > 
> 
> Thanks for pointing that out, I've got a v2 and will send it
> after some testing.  However, it looks like VDI doesn't have a
> magic, because there is a 40 Byte string at the start that cacn
> contain anything the creating binary puts there.  For example
> qemu-img uses "<<< QEMU VM Virtual Disk Image >>>\n".  According
> to [1], I'm adding "<<<" as the magic, because we don't fail if
> it doesn't match and we can still match it by the extension then.

No, you need to look at the 'signature'  field of the header
instead, which has a fixed magic value

  #define VDI_SIGNATURE 0xbeda107f

Daniel
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