[csw-maintainers] CSW packaged MTAs and /usr (continued from "CSWcswclassutils: it wants to write in /usr")

[Sebastian Kayser]

Greetings,

as our postfix packages needs some makeover, there is something I took
away from the discussion about cswclassutils and /usr [1] which relates
to our MTAs in general:

#1 Automatically messing with system binaries is considered evil.
   (e.g. /usr/lib/sendmail, /usr/bin/mailq, and /usr/sbin/newaliases)

#2 A CSW MTA that doesn't replace /usr/lib/sendmail isn't really
   integrated with the system (i.e. not guaranteed to catch all mail
   originating from the system)

Currently the postfix package automatically tries to move away the
system binaries and to link its own binaries into place. While this
tries to fully integrate with the system, it violates rule #1. There are
also a couple of bugs open against the package where this procedure
fails in sparse zone enviroments [2].

With an updated postfix package I would like to make the package as
simple as possible and leave control to the user. Therefor I would like
to emit a notification message on package installation, either pointing
the user to a README.CSW, a script, an additional integration package,
or simply to echo commands that one can issue to integrate postfix with
the system.

Now I am wondering what these commands should do. Should they mimic the
current behavior of

	mv <sysbin> <sysbin>.OFF && ln <cswbin> <sysbin>

or would it rather be preferable to say

	pkgrm <syssendmail-pkgs> && ln <cswbin> <sysbin>

I am specifically thinking about the latter option because of Solaris
patches. What would happen if we left the system sendmail packages in
place and simply moved away the binaries? Wouldn't a sendmail patch
notice the installed sendmail package and overwrite our link with
possibly patched binaries? Granted, pkgrm wouldn't make it easy for a
user to revert back to system sendmail .. just trying to get a feeling
for the different approaches.

Feedback very welcome!

Sebastian

[1] http://thread.gmane.org/gmane.os.solaris.opencsw.maintainers/4955
[2] http://www.opencsw.org/mantis/set_project.php?project_id=147