Fedora 10 - Boot Analysis

[Chris Adams]

Once upon a time, Arjan van de Ven <arjan at infradead.org> said:
> and it's not like sendmail/exim/whatever can't decide to become a daemon
> if it can't deliver... but only then.

That would require more privilege in the /usr/sbin/sendmail program.
For example, with sendmail, the binary is setgid-smmsp, which is just
enough privilege to write a new entry to the MSP queue directory.  You
probably don't want to run a new daemon as a normal user, so then you
have to have a setuid-(someuser|root) binary somewhere to start a daemon
on demand.

You'd still need to do something on boot, since there could be entries
in the queue from the last time the system was up (at which point, you
might as well just start a queue monitor daemon, maybe something using
inotify to only wake up when a new queue entry is written to be a little
more efficient).

Not saying it isn't possible, but it would take some (possibly not
insignificant) changes to make it work sanely and securely and cover the
corner cases correctly.

Also, part of the justification for a local MTA is that some programs
want to use SMTP on 127.0.0.1, which requires some kind of daemon
running there (either an MTA or xinetd to fork an MTA on demand).

If you want a local MTA (which IMHO should be there) and want to make it
work differently (start running a queue only on demand for example),
you're probably going to be better off writing an MTA to match your
special requirements (or starting off with something simple like ssmtp),
rather than trying to shoe-horn such changes into a "full fledged" MTA
like sendmail/postfix/etc.

-- 
Chris Adams <cmadams at hiwaay.net>
Systems and Network Administrator - HiWAAY Internet Services
I don't speak for anybody but myself - that's enough trouble.