[Q] How to detect if shadow passwords are installed ?

[Dirk Eddelbuettel <edd@rosebud.sps.queensu.ca>]

The xlockmore package, I've been told, should not be setuid root. However,
for shadow passwords, it needs to setgid shadow. I therefore contemplate
releasing xlock in as root.root in mode 0755, and if shadow is detected,
change to root.shadow 2755.  As shadow does exist as a group on non-shadow
systems, this seems the only way to handle this.

But how do I detect whether a system using shadow'ed passwords? Would this
work as a postinst:

#! /bin/sh

set -e 

case "$1" in
    configure)
	if [ -f /etc/shadow ]
	    echo "Preparing xlockmore for shadow passwords ..."
	    chgrp shadow /usr/bin/X11/xlock 
	    chmod 2755 /usr/bin/X11/xlock 
	fi
	;;
    abort-upgrade|abort-remove|abort-deconfigure)
	;;
    *)
	echo "postinst called with unknown argument \`$1'" >&2
	;;
esac

exit 0


If so, a problem remains that if someone has xlock installed on a non-shadow
system, and then switches to shadow, xlock will be broken. Guess that will be
another bug ...

-- 
 Dirk Eddelb"uttel    edd@poboxes.com    http://www.netforward.com/poboxes/?edd