dovecot - May 2020 - Directory hashing

Hi,

I struggle with directory hashing. I want something like this:

/srv/mail/c/cf37a8dff5e360927ba10ab2

The final folder is simpel, as it is:

%{sha256;truncate=96:user}

But how do I get a first level from sha256? Unfortunately, the truncate option
aligns only full 8bit and does not divide into low and high nibbles. How can I
express this for sha256?

in MD5 this would be %1Mu

Many thanks in advance

Christian
-- 
R??ner-Network-Solutions
Karl-Br?ger-Str. 10, 36304 Alsfeld
Fax: +49 6631 78823409, Mobil: +49 171 9905345
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In data luned? 11 maggio 2020 10:00:38 CEST, lists at mlserv.org ha
scritto:
> Hi,
> 
> I struggle with directory hashing. I want something like this:
> 
> /srv/mail/c/cf37a8dff5e360927ba10ab2
> 
> The final folder is simpel, as it is:
> 
> %{sha256;truncate=96:user}
> 
> But how do I get a first level from sha256? Unfortunately, the truncate
> option aligns only full 8bit and does not divide into low and high nibbles.
> How can I express this for sha256?
> 
> in MD5 this would be %1Mu
> 
> Many thanks in advance
> 
> Christian
Maybe as a workaround you can create a directory named /srv/mail/c and make 16 
symbolic links to it: /srv/mail/c0, /srv/mail/c1, /srv/mail/c2,  up to /srv/
mail/cf.

In that way you can use truncate=8.



-- 
Simone Lazzaris
QCom SpA

> On 11/05/2020 11:10 Simone Lazzaris <s.lazzaris at interactive.eu>
wrote:
> 
>  
> In data luned? 11 maggio 2020 10:00:38 CEST, lists at mlserv.org ha
scritto:
> > Hi,
> > 
> > I struggle with directory hashing. I want something like this:
> > 
> > /srv/mail/c/cf37a8dff5e360927ba10ab2
> > 
> > The final folder is simpel, as it is:
> > 
> > %{sha256;truncate=96:user}
> > 
> > But how do I get a first level from sha256? Unfortunately, the
truncate
> > option aligns only full 8bit and does not divide into low and high
nibbles.
> > How can I express this for sha256?
> > 
> > in MD5 this would be %1Mu
> > 
> > Many thanks in advance
> > 
> > Christian
> 
> Maybe as a workaround you can create a directory named /srv/mail/c and make
16
> symbolic links to it: /srv/mail/c0, /srv/mail/c1, /srv/mail/c2,  up to
/srv/
> mail/cf.
> 
> In that way you can use truncate=8.
> 
> 
> 
> -- 
> Simone Lazzaris
> QCom SpA
Out of curiosity, but why do you use SHA256? You get probably no extra benefit
from it. I mean, you are free to do so, but ... why?

Anyways, it would work pretty much the same way, %1{sha256:..} and
%4{sha256:...}.

Aki