#!/usr/local/bin/perl
#
# autowarn
# v .01
#
# this should be run every nite by cron.
#
# it will scan all the accounts in /etc/shadow and
# for any that have exactly (10,30,etc) days left before
# expiring, it will send an email to those accounts with
# a warning.
#
# miff, 2000
#

#this whole deal is gonna be a simple subtraction of the system
# date from the expir date (since the expir date is in days)
# in "days since 1970"

#set some constants:
$file_of_interest = '/etc/shadow';
$secs_per_day = 86400;

#set today:
$today = int(time / $secs_per_day);

print "autowarn expiration date checker by miff\n\n";
print "today appears to be $today in system time... \n";

open (SHADOW, $file_of_interest) || die "big problems opening $file_of_interest\n\n";
while ($input = <SHADOW>) {
	chomp $input;
	@fields = split (":",$input);
	if ($fields[7])  {    # we have an expiration date
		print "user $fields[0], expiration date (machine time) = $fields[7] \n";
		$days_till_expiry = int($fields[7]) - $today;
		$message = "System autowarn:  Your account will expire in $days_till_expiry days!  \n\n";
		if ($days_till_expiry == 10) {
			print "10 days left for $fields[0]\n";
			system("echo '$message' | mail $fields[0]");
		} elsif ($days_till_expiry == 30) {
			print "30 days left for $fields[0]\n";
			system("echo '$message' | mail $fields[0]");
		} elsif ($days_till_expiry == 5) {
			print "5 days left for $fields[0]\n";
			system("echo '$message' | mail $fields[0]");
		} elsif ($days_till_expiry == 1) {
			print "1 day left for $fields[0]\n";
		}
	}
}
close (SHADOW);