Re: [Exim] Released: SpamAssassin at SMTP time in local_scan

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Auteur: David Woodhouse
Date:  
À: Matt Bernstein
CC: dman, exim-users
Nouveaux-sujets: [Exim] Re: dynamic local_scan and other modules (was Re: Released: SpamAssassin at SMTP time in local_scan)
Sujet: Re: [Exim] Released: SpamAssassin at SMTP time in local_scan
mb@??? said:
> >> In fact, this would be nice for the various lookups and mailstore
> >> formats too. Packages could provide a base exim with the rest as
> >> separate add-on modules loadable at runtime.
> >
> >Left as an exercise for the reader.
>
> I don't know if such modifications would make it into Philip's Exim,
> though. I quite like the argument "if you can't build an MTA, you
> shouldn't be admin of one"--just think of the extra noise on a list
> such as this should Red Hat offer packages for exim, exim-mysql,
> exim-maildir..


I can't see the point in it for exim-maildir. Perhaps for stuff like
ldap, perl or mysql though -- things that if built-in require other support
libraries and perhaps would prevent the Exim binary from running or the
package from installing in their absence. If those modules were shipped as
dynamic shared objects, Exim could try to load them but cope gracefully if
the libraries which they require are not present.

You don't actually have to ship the extra modules in separate packages. But
yes -- that perhaps wants a little more thought and might not want to get
incorporated into Exim proper, as it's definitely a distribution issue.

> Otoh I do like the local_scan being a dynamic shared object: it "would
> be nice" to be able to plug more than one such object into an Exim, so
> that you have lots of small bits of obviously correct code--maybe one
> for your virus scanner, one for SpamAssassin, one for
> some-sort-of-PGP-validator, etc--and you can just chain them together.


Yeah -- being able to load more than one local_scan function and call them
in the order specified un{til,less} one fails would perhaps be a useful
feature. It shouldn't be that hard to extend the code I hacked up to do
that.

Again, left as an exercise...

We may want to consider changing stuff around so an Exim daemon would load
the local_scan libraries first, rather than _every_ child having to do so
upon receiving its first message. OTOH, we may not want to bother -- I
don't really know how expensive dlopen() is.

--
dwmw2