($utmp_file) = @ARGV;

print "Parsing file:$utmp_file\n";

$struct_utmp = "A8A4A12NnnnnNA16N";

# Todos los numéricos están dados en Network Format (es decir, big endian)

# Tipos de u_type

@u_type = ( 'EMPTY','RUN_LVL','BOOT_TIME','OLD_TIME','NEW_TIME',        
            'INIT_PROCESS',    #      /* Process spawned by "init" */
            'LOGIN_PROCESS',   #      /* getty process awaiting login */
            'USER_PROCESS',    #      /* A user process */
            'DEAD_PROCESS',    
            'ACCOUNTING',      
          );



$length = length(pack($struct_utmp));

open(UTMP, $utmp_file) || die "open: $!\n";
binmode UTMP;


print "user,id,line,pid,type,exit_status_termination,exit_status_exit,reserved,time,host,addr\n"; 	

while (read(UTMP, $_, $length)) {
   ($user, $id, $line, $pid, $type, $exit_status_termination,$exit_status_exit, $reserved, $time, $host, $addr) =  unpack($struct_utmp, $_);
   print "$user,$id,$line,$pid,$u_type[$type],$exit_status_termination,$exit_status_exit,$reserved,", scalar localtime($time),",$host,",Integer2Ip($addr),"\n"; 	

}

close(UTMP);



############################################################################
#
#   Name:    Integer2Ip
#
#   Purpose: Convert an integer value into an dotted quad
#
#   Inputs:  $integer - Integer value
#
#   Returns: Dotted quad string, dies in case of problems
#
############################################################################

sub Integer2Ip ($) {
    my $integer = shift;
    my $four = $integer & 0xff;
    $integer >>= 8;
    my $three = $integer & 0xff;
    $integer >>= 8;
    my $two = $integer & 0xff;
    $integer >>= 8;
    my $one = $integer;
    "$one.$two.$three.$four";
}