#!/usr/bin/perl

$now = time;
$DELTA = 2*60*60;
@mo = (Jan,Feb,Mar,Apr,May,Jun,Jul,Aug,Sep,Oct,Nov,Dec);

open(UTMP,'/etc/utmp') 	|| die "can't open utmp: $!";
chdir '/dev' 		|| die "can't cd to /dev: $!";
open(TTYS, "/etc/ttys") || die "can't open /etc/ttys: $!";

@tty = ('console');

($tty[$.]) = /^\d*(\S+)/ while <TTYS>;

for ($slot = 0; read(UTMP,$utmp,36); $slot++) {
    $hidden = 0;
    ($line,$name,$host,$time) = unpack('A8 A8 A16 l', $utmp);
    if (!$line) {
	$hidden++;
	$line = $tty[$slot];
    } else {
	die "$line ne $tty[$slot]" if $line ne $tty[$slot]; 
    } 
    ($who, $when) = (stat($line))[4,9];
    if (!$who && $hidden) {
	next unless $when + 5*60 > $now;
	#print "root on $line, last touched $when, now is $now\n";
    } 
    #next if $hidden && !$who && ($when + 5*60) > $now;
    #next if $hidden && $when + $DELTA < $now;
    $time = $when if $hidden;
    if ($name || $hidden) {
	if ($hidden) {
	    $name = &name($who);
	    &paren($name) if $hidden;
	} 
	&paren($host);
	($sec,$min,$hour,$mday,$mon) = localtime($time);
	$date = sprintf("%s %2d %02d:%02d", $mo[$mon],$mday,$hour,$min);
	$date = $hidden ? "($date)" : " $date ";
	printf "%-10s%-8s %s  %s\n", $name,$line,$date, $host;
    }
}   

sub paren { $_[0] = "($_[0])" if $_[0]; } 

sub name {
    local($id) = shift;
    $id{$id} = (getpwuid($id))[0]	unless defined $id{$id};
    $id{$id};
}