This basically the app server code,

# signal handler for child die events
$SIG{TERM} = $SIG{INT} = \&do_term;
$SIG{HUP}  = \&do_hup;

our($listen_socket);

$listen_socket = HTTP::Daemon->new(LocalPort => PORT) or
 die "Can't create a listening socket: $@" unless $listen_socket;

my $pid = init_server(PIDFILE, USER, @groups);
my $port = PORT;
log_notice("App Server accepting connections on port $port\n");

while (my $connection = $listen_socket->accept)
{
    my $host = $connection->peerhost;
    my $child = launch_child(undef, undef);
    if ($child == 0)
    {
        $listen_socket->close;
        log_notice("App Srv : Accepting a connection from $host\n");
        my ($fnm, $prg) = launch_app($connection);
        my $child = launch_child(undef, undef);
        if ($child == 0) {
            log_notice("Otools App Srv : Running $prg\n");
            ($<, $>) = ($>, $<); # Switch EUid & RUid.
            $> = $<;
            log_notice("Uid = $< : Eid  = $>\n");
            log_notice("Gid = $( : EGid = $)\n");
            exec($prg, $fnm, $host) or
                log_die("App Srv : Exec failed. Died");
        }
        log_notice("App Srv : Connection from $host finished\n");
        exit 0;
    }

} continue { $connection->close; }
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I am using HTTP::Daemon to listen for posts on a port and I use the Daemon.pm launch the children, initialize, ...etc. I was debugging the server so I commented out the become_daemon() sub and ran in the debugger. Of course the server stayed running, not exiting after one request. As soon as I put the become_daemon() back into the code and start the server, it quits after handling one request. Here is the become_daemon() sub from Lincoln's book,

sub become_daemon {
  croak "Can't fork" unless defined (my $child = fork);
  exit 0 if $child;    # parent dies;
  POSIX::setsid();     # become session leader
  open(STDIN,"</dev/null");
  open(STDOUT,">/dev/null");
  open(STDERR,">&STDOUT");
  $CWD = getcwd;       # remember working directory
  chdir '/';           # change working directory
  umask(0);            # forget file mode creation mask
  $ENV{PATH} = '/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin';
  delete @ENV{'IFS', 'CDPATH', 'ENV', 'BASH_ENV'};
  $SIG{CHLD} = \&reap_child;
}
[download]