diff -r 4e7411db8f9e -r 6603c56acc92 greylist.pl
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/greylist.pl	Sun Dec 31 20:16:46 2006 +0000
@@ -0,0 +1,90 @@
+# © 2006,2007 Heiko Schlittermann <hs@schlittermann.de>
+# $Id$
+# $URL$
+
+use strict;
+use warnings;
+use BerkeleyDB;
+
+my %DEFAULT = (
+	delay => 600,
+	db => "seen.db",
+);
+
+sub unseen($;$$);
+
+sub getDBDir();
+sub findExim();
+sub getDefault() { %DEFAULT };
+
+# Usage:
+# 	${perl{unseen}{$sender_host_address}}
+# 	${perl{unseen}{$sender_host_address}{600}}
+# 	${perl{unseen}{$sender_host_address}{600}{seen.db}}
+# 	${perl{unseen}{$sender_host_address}{600}{/some/dir/seen.db}}
+#
+# record structure: item\0 timestamp(creation)\0 timestamp(usage)\0
+# (This way we're compatible with ${lookup{...}dbm{...}}
+sub unseen($;$$) {
+	my ($item, $delay, $db) = @_;
+		$item .= "\0";
+		$delay = $DEFAULT{delay} unless defined $delay;
+		$db = $DEFAULT{db} unless defined $db;
+
+	my $now = time();
+	my $umask;
+	my $rc;
+
+	$db = getDBDir() . "/$db" unless $db =~ /^\//;
+
+	$umask = umask 0077 if !-f $db;
+
+	my %h; tie %h, "BerkeleyDB::Hash", 
+		-Filename => $db,
+		-Flags => DB_CREATE
+	or die;
+
+	umask $umask if defined $umask;
+
+	if (not exists $h{$item}) {
+		$h{$item} = "$now $now\0";
+		$rc = "yes";
+	} else {
+		my $created = (split " ", $h{$item})[0];
+		if ($now - $created < $delay) { $rc = "yes" }
+		else { 
+			$rc = "no";
+			$h{$item} = "$created $now\0";
+		}
+	}
+	untie %h;
+	return $rc;
+}
+
+# Get the directory where we could store the database file(s)
+# If we're running under exim it's easy, otherwise we've to find exim
+# and then ask...
+sub getDBDir() {
+	my $spooldir;
+	eval { $spooldir = Exim::expand_string('$spool_directory') };
+	if (not defined $spooldir) {
+		my $exim = findExim();
+		chomp($spooldir = `$exim -be '\$spool_directory'`);
+		die "Can't find spooldir" if not defined $spooldir;
+	}
+	return "$spooldir/db";
+}
+
+sub findExim(;$) {
+	my $path = shift || $ENV{PATH};
+	my $exim;
+	foreach (split /:/, $ENV{PATH}) {
+		-x ($exim = "$_/exim") and return $exim;
+		-x ($exim = "$_/exim4") and return $exim;
+	}
+	return undef;
+}
+
+1;
+
+# vim:aw: