#! /usr/pkg/bin/perl -W

#
# $Netilium: fetch_mail_statistics.pl,v 1.6 2004/11/07 21:59:11 mad Exp $
#
# Calculate and return number of sent / received e-mails on a system
# running the Postfix MTA. This is done by incrementally reading the
# log file, in a ``tail''-like fashion.
#                                              7th of November, 2004
#                                          http://netilium.org/~mad/
#                                Martin Adolfsson <mad@netilium.org>


#
# This defines how many seconds we will cache calculated values.
#
$MINRESET = 1200;


if ( @ARGV < 5 ) {
print <<EOF
usage: fetch_mail_statistics.pl <maillog> <db file> <base oid> <request type> <requested oid>

 where:
   <maillog>         Mail log file, in Postfix compatible format.
   <db file>         File for logging statistics and timestamp data.
   <base oid>        The base OID this script is mounted on.
   <request type>    -n for SNMP getNext, or -g for SNMP get.
   <request oid>     Requested OID, in accordance with previous parameter

Report bugs to: <mad\@netilium.org>
EOF
;
exit;
}

$logFile  = $ARGV[0];
$dbFile   = $ARGV[1];
$baseOid  = $ARGV[2];

(@lf = stat $logFile) || die( "Cannot stat log file `".$logFile."'!" );
@st = stat $dbFile;

if ( ! @st ) {
  $timeSinceUpdated = 99999999;
  $logPosition      = $lf[7];
} else {
  $timeSinceUpdated = time()-$st[9];
  open( DBFILE, $dbFile ) || die( "Cannot open db file `".$dbFile."'!" );
  $logPosition=<DBFILE>;
  close( DBFILE );
  if ( $logPosition > $lf[7] ) {
    # Log has been truncated since last run.
    $logPosition = 0;
  }
}

if ( $timeSinceUpdated > $MINRESET ) {
  # Calculate and store new data.
  open( LOGFILE, $logFile ) || die( "Cannot open log file `".$logFile."'!" );
  seek( LOGFILE, $logPosition, 0 );
  $num_rec = 0;
  $num_sent = 0;
  while( <LOGFILE> ) {
    if ( /: message-id=</ ) { $num_rec++; }
    elsif ( /status=sent/ && ! /relay=(mailfilter|procmail|local)/ ) { $num_sent++; }
  }
  open( DBFILE, ">".$dbFile ) || die( "Cannot write to db file `".$dbFile."'!" );
  print DBFILE tell(LOGFILE)."\n";
  print DBFILE $num_rec."\n";
  print DBFILE $num_sent."\n";
  close( DBFILE );
}

# Return archived data.
open( DBFILE, $dbFile ) || die( "Cannot open db file `".$dbFile."'!" );
@data = ();
while( <DBFILE> ) { chomp; push @data, $_; }

$reqMethod = $ARGV[3];
$reqOid    = $ARGV[4];

if ( $reqMethod eq "-n" ) {
  # SNMP getNext request.
  if ( $reqOid eq $baseOid ) {
    print $baseOid.".0\ninteger\n".$data[1]."\n";
  } elsif ( $reqOid eq $baseOid.".0" ) {
    print $baseOid.".1\ninteger\n".$data[2]."\n";
  }
} elsif ( $reqMethod eq "-g" ) {
  # SNMP get request.
  if ( $reqOid eq $baseOid || $reqOid eq $baseOid.".0" ) {
    print $baseOid.".0\ninteger\n".$data[1]."\n";
  } elsif( $reqOid eq $baseOid.".1" ) {
    print $baseOid.".1\ninteger\n".$data[2]."\n";
  }
}