[et-mgmt-tools] [patch] virt-convert add disk signature into virt-image format export

[Cole Robinson]

Daniel P. Berrange wrote:
> On Tue, Sep 30, 2008 at 05:39:13PM -0400, Joey Boggs wrote:
>> Here's a sample that works, just want to verify it's alright. Is 64MB 
>> too much/too little to read at one time?
>>
>>
>> f = open("test.raw","r")
>> m = sha.new()
>> while 1:
>>    chunk = f.read(65536)
>>    if not chunk:
>>        break
>>    m.update(chunk)
>> print m.hexdigest()
> 
> Both md5 and sha1 are becoming obsolete, and indeed forbidden by some
> of the more paranoid organizations. I'd recommend we go straight
> to using at least sha256. Also the docs recommend using  hashlib module
> directly, eg
> 
>     import hashlib
> 
>     m = hashlib.sha256()
>     while 1:
>       chunk = f.read(65536)
>       if not chunk:
>         break
>       m.update(chunk)
>     print m.hexdigest()
> 
> Daniel

Yeah, the only problem with hashlib is that it's python2.5
only. But we could just catch the import error and disable
the functionality if need be.

As far as md5 or sha1, no comment, though we probably want
to support whatever other config formats use (if any do
indeed offer hash support).

- Cole