[Buildroot] [PATCH 5/6] pkg-infra: add possiblity to check downloaded files against known hashes

[Yann E. MORIN <yann.morin.1998@free.fr>]

Arnout, All,

On 2014-01-15 09:22 +0100, Arnout Vandecappelle spake thusly:
> On 15/01/14 00:34, Yann E. MORIN wrote:
> >Arnout, All,
> >
> >On 2014-01-14 22:37 +0100, Arnout Vandecappelle spake thusly:
> >>On 13/01/14 00:44, Yann E. MORIN wrote:
> [snip]
> >>>Note-2: The laternative to sha1 would be sha2 (256- or 512-bit), but
> >>>oldish "enterprise-class" distributions  may be missing them entirely.
> >>>sha256sum and sha512sum were added to coreutils in 2005-10-23, and RHEL5
> >>>seems to have them. But better be safe than sorry. If sha2 should be
> >>>considered instead of sha1, then it is very easy to switch now. Switching
> >>>later would require that we revalidate all packages that have hashes,
> >>>which could prove to be quite time-demanding if we have lots of
> >>>packages using hashes.
> >>
> >>  We can be more future-safe by storing the hash that is used in the .hash
> >>file itself.
> >
> >Hu?
> 
>  If the hash file contains the following:
> 
> 486fb55c3efa71148fe07895fd713ea3a5ae343a  sha1  libfoo-1.2.3.tar.bz2

OK, I see what you meant, now.

> then you can now let the script check that the second field is sha1, and
> later you can support different hash methods. In that case, it is not
> necessary to update all the files when we want to switch to a new hash
> method.

However, that means the file is no longer the output of:
    sha1sum files-to-check* >package.hash

or of any other hash utility: sha*sum all generates similarly-formatted
outputs:
    hash <two spaces> filename

Which was the reason I choose that format.

If we'd use your suggestion, we'd need a simple way to generate that
file, or it'd be error prone.

Regards,
Yann E. MORIN.

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