Executing session "hooks"

[Olle Mulmo]

Hi,

I call this "session hooks" because I don't know what else to call it.
What I mean is the extra "stuff" that will happen before and after a
login session or a command gets executed, such as fetching AFS tokens
upon startup and destroying kerberos tickets upon shutdown.

My need for this patch occured when I needed a couple of additional
"hooks" that wasn't supported. I started out trying to throw them in
as a local hack, but then discovered clashes between some of the
libraries that the various pieces of software used.

Thus, I ended up adding a generic hook that executes a configurable
external command. In my case, it is a shell script that in turn
executes a sequence of command-line tools from the various non-compatible
software distributions.

The end result is the same, with one exception: when invoking external
commands instead of library routines, the are run as separate processes
and thus cannot define or modify the user's environment. Thus, support
to convey this information from the session hook was added as well. The
solution here is a bit rough at the edges (create a temporary
environment file that is then sourced by the other process) but it works.

Please take a look at these contributions, give feedback, and let me know
if you would consider it for inclusion in future releases of OpenSSH:

http://www.pdc.kth.se/~mulmo/session-hooks/

Regards,

/Olle