#!/usr/bin/perl

=head1 NAME

mailman - Plugin to monitor activity on mailman mailing list
management systems

=head1 CONFIGURATION

Configuration for this plugin depends on the mailman's settings on the
system. Here are the defaults:

[mailman]
  env.logfile /var/log/mailman/post
  env.libdir  /var/lib/mailman
  env.lister  /usr/lib/mailman/bin/list_members

=head1 AUTHOR

Author unknown.  Source code strongly related to the Exim plugin of old.

=head1 LICENSE

License unknown

=head1 MAGIC MARKERS

 #%# family=contrib
 #%# capabilities=autoconf

=cut

$statefile = "$ENV{MUNIN_PLUGSTATE}/munin-mailman-log.state";
$pos = undef;
$posts = 0;
$members = 0;

# System paths
$logfile = $ENV{'logfile'} || "/var/log/mailman/post";
$libdir  = $ENV{'libdir'}  || "/var/lib/mailman";
$lister  = $ENV{'lister'}  || "/usr/lib/mailman/bin/list_members";

if (-f "$logfile.0")
{
    $rotlogfile = $logfile . ".0";
}
elsif (-f "$logfile.1")
{
    $rotlogfile = $logfile . ".1";
}
elsif (-f "$logfile.01")
{
    $rotlogfile = $logfile . ".01";
}
else
{
    $rotlogfile = undef;
}

if($ARGV[0] and $ARGV[0] eq "config") {
    print "graph_title Mailman usage\n";
    print "graph_args --base 1000\n";
    print "graph_category mailinglist\n";
    print "posts.label posts per minute\n";
    print "posts.type DERIVE\n";
    print "posts.min 0\n";
    print "members.label members\n";
    print "members.type GAUGE\n";
    exit 0;
}

if($ARGV[0] and $ARGV[0] eq "autoconf") {
    if(-f $logfile && -d $libdir && -x $lister ) {
        print "yes\n";
    } else {
        print "no (can not find file $logfile or dir $libdir or executable $lister)\n";
    }
    exit 0;
}

if(! -f $logfile &&
   ! -d $libdir &&
   ! -x $lister) {
    print "posts.value U\n";
    print "posts.extinfo Can't find any log files\n";
    print "members.value U\n";
    exit 0;
}

if(-f $statefile) {
    open(IN, "<$statefile") or die "Can't open $statefile for reading: $!";
    if(<IN> =~ /^(\d+):(\d+)/) {
	($pos,$posts) = ($1, $2);
    }
    close(IN);
}

$startsize = (stat $logfile)[7];

if(!defined $pos) {
    # Initial run.
    $pos = $startsize;
    $startsize = 0;
} elsif($startsize < $pos) {
    # Log rotated
    if(defined $rotlogfile) {
	parseMailmanLog($rotlogfile, $pos, (stat $rotlogfile)[7]);
    }
    $pos = 0;
}

parseMailmanLog($logfile, $pos, $startsize);
$pos = $startsize;

parseMailmanLists();

print "posts.value $posts\n";
print "members.value $members\n";

open (OUT, ">$statefile") or die "Can't open $statefile for writing: $!";
print OUT "$pos:$posts\n";
close OUT;

sub parseMailmanLog {
    my($fname, $start, $stop) = @_;
    open(LOGFILE, $fname) or die "Can't open $fname for reading: $!";
    seek(LOGFILE, $start, 0) or die "Can't seek in $fname: $!";
    while(tell(LOGFILE) < $stop) {
	my $line = <LOGFILE>;
	if($line =~ / post to/) {
	    $posts++;
	}
    }
    close(LOGFILE);
}

sub parseMailmanLists {
    my @domains = &mailmanDomains;
    for(my $i = 0; $i < @domains; $i++) {
        my @lists = &mailmanLists($domains[$i]);
        for(my $j = 0; $j < @lists; $j++) {
            $members += &mailmanMembers($domains[$i], $lists[$j]);
        }
    }
}

sub mailmanDomains {
    my @domains;
    if (-e "$libdir/data") {
	@domains = (".");
    } else {
	opendir(DOMAINS, $libdir) or
	    die "Can't open directory $libdir for reading: $!";
	@domains = grep ( { !/^\@/ && !/^\./ && -d "$libdir/$_" }
			  readdir(DOMAINS) );
	closedir(DOMAINS);
    }
    return @domains;
}

sub mailmanLists {
    my ($domain) = @_;
    opendir(LISTS, "$libdir/$domain/lists") or
	die "Can't open directory $libdir/$domain/lists for reading: $!";
    my @lists = grep ( { !/^\@/ && !/^\./ && -d "$libdir/$domain/lists/$_" }
		       readdir(LISTS) );
    closedir(LISTS);
    return @lists;
}

sub mailmanMembers {
    my ($domain, $list) = @_;
    return 0 unless $domain;
    return 0 unless $list;
    my $cnt = 0;
    open(MEMBERS, "DOMAIN=$domain $lister $list|") or
	die "Cannot execute pipe: $lister $list: $!";
    while(<MEMBERS>) {
        $cnt++;
    }
    close(MEMBERS);
    return $cnt;
}