[Reproducible-builds] Bug#820631: Bug#820631: support for concatenated cpio archives

[Zbigniew Jędrzejewski-Szmek]

On Sun, Apr 10, 2016 at 10:34:59PM +0200, Reiner Herrmann wrote:
> Hi Zbigniew,
> 
> thanks for the report!
> I just had a short look at this issue.
> The problem why diffoscope doesn't see this change is that the initramfs
> contains actually multiple cpio archives, but diffoscope treats
> the files as single cpio archives:
> 
> > $ cpio -t < initrd 
> > .
> > early_cpio
> > kernel
> > kernel/x86
> > kernel/x86/microcode
> > kernel/x86/microcode/GenuineIntel.bin
> 
> And the files in this first/visible archive don't differ.
> 
> Right now it doesn't know that somewhere in the original file an additional
> archive is embedded.
> And so it falls back to a hexdump/binary diff, as the files clearly
> differ, but it didn't find any more readable difference.
> 
> To solve this, diffoscope either needs to learn about initramfs files,
> or (to have a more general solution) use binwalk for extracting data
> embedded into other files (this would require #819018 first).

Thanks for the quick diagnosis.
I think that using binwalk as a general solution sounds better. 
I'll wait then for diffoscope to acquire that capability.
In Fedora we're lucky, binwalk already provides python3 modules (in fact
only python3 modules, without python2 support).

Zbyszek