[PATCH] Kerberos support for screen

[Fredrik Tolf]

Hi all!

I was having some trouble with Kerberos and screen, so I wrote this
patch. Not sure if I should send patches to "screen-users", but I
couldn't find any other mailing list. =)

Anyway, my basic problems were two:
1. If one logs in with Kerberos support and thereby gets tickets and
then starts a screen, that screen session will use the same credential
cache. If one then detaches the screen and logs out, the login program
will remove the credential cache, and the processes running in the
detached screen will be ticket-less. Therefore, this patch makes a copy
of the credential cache and ensures that all processes in the screen
session will use it.

2.  If I start a screen, detach it and let it lie for some time, the
tickets will expire if I don't manually log in once in a while and renew
them manually. Therefore, this patch renews the tickets when necessary
(it registers an event that runs once per minute and examines if it's
time to renew the tickets, and does so if it deems it good).

If you apply the patch, you'll need to run configure with --with-krb5
(no auto-detection is done). It requires either MIT Krb5 or a compliant
API (I think it should support Heimdal, but I haven't tried, so I don't
know).

The patch (and two auxiliary patches) is available at
<http://www.dolda2000.com/~fredrik/patches/>. I tried to send this mail
with the patch attached at first, but it crossed the message size limit
of the list.

I'd be glad if this appears in a future version of screen, so that I
don't have to patch it manually for much longer. ;-)

I hope it helps someone.

Fredrik Tolf