#!/opt/bin/perl
#
#########################################################################
#                                                                       #
#     Program for receiving e-mails and storing or forwarding them      #
#                                                                       #
#########################################################################
#                                                                       #
#   Version 1.0     -   Written 24.08.95 by Steffen Beyer               #
#                                                                       #
#########################################################################
#                                                                       #
#   Copyright (C) 1995 by software design & management GmbH & Co. KG    #
#                                                                       #
#########################################################################
#
# Some important default settings:
#
$version = 'Version 1.0';
#
$self = $0;
#
if ($self =~ m!/([^/]+)$!) { $self = $1; }
#
# Define here the name of your mailbox (MUST be an ABSOLUTE path!!!):
#
$mailbox = '/var/spool/mail/wolfgang';
#
$lockfile = "$mailbox.lock";
#
$tempfile = "$mailbox.temp";
#
# To disable the creation of the mailbiffer flag file, comment out this line:
#
$mailflag = "$mailbox.bif";
#
# Define here the forwarding (e-mail) address:
#
$address = "sb@sdm.de";
#
$wait = "true";
#
# Wait for semaphore:
#
while ($wait)
{
    #
    # Wait for semaphore to be released (if set):
    #
    while (-f $lockfile) { sleep(5); }
    #
    # When semaphore is gone, create own one:
    #
    unless (open(LOCKFILE, ">>$lockfile"))
    {
        unlink($lockfile);
        die "Can't open semaphore for writing: $!\n";
    }
    print LOCKFILE "$$\n";
    close(LOCKFILE);
    #
    # Check wether semaphore is our's or was created
    # in the meantime by another copy of this process
    #
    unless (open(LOCKFILE, "<$lockfile"))
    {
        unlink($lockfile);
        die "Can't open semaphore for reading: $!\n";
    }
    $_ = <LOCKFILE>;
    chop;
    close(LOCKFILE);
    #
    # Loop if semaphore isn't our's:
    #
    $wait = ($_ != $$);
    if ($wait)
    {
        warn "Semaphore access conflict detected!\n";
        warn "Waiting for other process to terminate.\n";
    }
}
#
# Write incoming mail to temporary file and determine wether to forward it:
#
unless (open(TEMPFILE, ">$tempfile"))
{
    unlink($lockfile);
    unlink($tempfile);
    die "Can't open tempfile for writing: $!\n";
}
#
while (<STDIN>)
{
    chop;
    print TEMPFILE $_, "\n";
    if (($subject eq "") && (/^Subject:\s*(.*)$/)) { $subject = $1; }
    #
    # Define here the forwarding condition(s):
    #
    if    (/Lotus.*Notes/i) { $forward = true; }
    elsif (/\bNotes\b/i)    { $forward = true; }
    elsif (/\bMIS\b/)       { $forward = true; }
    else  { }
}
#
close(TEMPFILE);
#
if ($subject eq "")
{
    $subject = "Betreff: Lotus Notes";
}
#
if ($forward ne "")
{
    system("cat $tempfile | /opt/bin/elm -s \'$subject\' $address");
    $rc = ($? >> 8);
}
else
{
    system("cat $tempfile >> $mailbox");
    $rc = ($? >> 8);
    if ($mailflag ne "")
    {
        system("touch $mailflag");
    }
}
#
unlink($tempfile);
#
# Release semaphore:
#
unlink($lockfile);
#
# Done:
#
exit $rc