From: rjones <rjones>
Date: Thu, 28 Jun 2007 19:47:26 +0000 (+0000)
Subject: Initial version.
X-Git-Url: http://git.annexia.org/?p=xavierbot.git;a=commitdiff_plain;h=d165f93ed79c62a1fa76f391d87ffc4d215b9efe;hp=317ecc32edbd2757c6d9bf0311bd1391ec44cfc8

Initial version.
---

diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..fb78aa0
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,36 @@
+# $Id: Makefile,v 1.1 2007/06/28 19:47:26 rjones Exp $
+
+include Makefile.config
+
+CC	:= gcc
+CFLAGS	:= -Wall -Werror
+
+all: pa_noexternal.cmo init ocamlbotwrapper xavierbot.pl
+
+ocamlbotwrapper: ocamlbotwrapper.o
+	$(CC) $(CFLAGS) $< -o $@
+
+ocamlbotwrapper.c: ocamlbotwrapper.c.in Makefile.config
+	sed \
+	  -e 's|@OCAML@|$(OCAML)|' \
+	  -e 's|@INITSCRIPT@|$(INITSCRIPT)|' \
+	  < $< > $@
+
+init: init.in Makefile.config
+	sed \
+	  -e 's|@OCAMLUSER@|$(OCAMLUSER)|' \
+	  -e 's|@CHROOTDIR@|$(CHROOTDIR)|' \
+	  < $< > $@
+
+xavierbot.pl: xavierbot.pl.in Makefile.config
+	sed \
+	  -e 's|@WRAPPER@|$(WRAPPER)|' \
+	  < $< > $@
+	chmod 0755 $@
+
+pa_noexternal.cmo: pa_noexternal.ml
+	ocamlfind ocamlc \
+	  -pp "camlp4o pa_extend.cmo q_MLast.cmo" -I +camlp4 -c $<
+
+clean:
+	rm -f ocamlbotwrapper *.o *.cmo *.cmi *~
\ No newline at end of file
diff --git a/Makefile.config b/Makefile.config
new file mode 100644
index 0000000..f8022b1
--- /dev/null
+++ b/Makefile.config
@@ -0,0 +1,28 @@
+# $Id: Makefile.config,v 1.1 2007/06/28 19:47:26 rjones Exp $
+
+PACKAGE := xavierbot
+VERSION := 0.1
+
+# Prefix for installation.
+# - Binaries are installed in $(PREFIX)/sbin
+# - Other files go in $(PREFIX)/share/$(PACKAGE)
+PREFIX=/usr/local
+
+BINDIR=$(PREFIX)/bin
+SBINDIR=$(PREFIX)/sbin
+DATADIR=$(PACKAGE)/share/$(PACKAGE)
+
+# Install location of the SUID wrapper.
+WRAPPER=$(SBINDIR)/ocamlbotwrapper
+
+# Location where the init script is installed.
+INITSCRIPT=$(DATADIR)/init
+
+# Location (directory) for chrooted environment.
+CHROOTDIR=/var/local/xavierbot/chroot
+
+# Location of ocaml program.
+OCAML=/usr/bin/ocaml
+
+# OCaml command user.
+OCAMLUSER=nobody
diff --git a/init b/init
new file mode 100644
index 0000000..0401dba
--- /dev/null
+++ b/init
@@ -0,0 +1,147 @@
+(* Initialise the toplevel environment.
+ * $Id: init,v 1.1 2007/06/28 19:47:26 rjones Exp $
+ * - Removes the Pervasives module and any dangerous functions.
+ * - Loads just the modules we want to give access to, and just
+ *   the functions within those modules that we want to give.
+ * - Sets up our custom camlp4 grammar which removes "external"
+ *   keyword.
+ * - Chroot to somewhere safe.
+ *)
+
+(* Remove the Pervasives module. *)
+module Pervasives = struct end;;
+
+(* Remove any unsafe imported functions. *)
+let open_out = ()
+let open_out_bin = ()
+let open_out_gen = ()
+let flush = ()
+let flush_all = ()
+let output_value = ()
+let seek_out = ()
+let close_out = ()
+let close_out_noerr = ()
+let set_binary_mode_out = ()
+
+let open_in = ()
+let open_in_bin = ()
+let open_in_gen = ()
+let input_char = ()
+let input_line = ()
+let input = ()
+let really_input = ()
+let input_byte = ()
+let input_binary_int = ()
+let input_value = ()
+let seek_in = ()
+let pos_in = ()
+let in_channel_length = ()
+let close_in = ()
+let close_in_noerr = ()
+let set_binary_mode_in = ()
+
+module LargeFile = struct end;;
+
+(* let exit = () -- do this later *)
+let at_exit = ()
+let valid_float_lexem = ()
+let unsafe_really_input = ()
+let do_at_exit = ()
+
+(* Allow the List function. *)
+module List : sig
+  val length : 'a list -> int
+  val hd : 'a list -> 'a
+  val tl : 'a list -> 'a list
+  val nth : 'a list -> int -> 'a
+  val rev : 'a list -> 'a list
+  val append : 'a list -> 'a list -> 'a list
+  val rev_append : 'a list -> 'a list -> 'a list
+  val concat : 'a list list -> 'a list
+  val flatten : 'a list list -> 'a list
+  val iter : ('a -> unit) -> 'a list -> unit
+  val map : ('a -> 'b) -> 'a list -> 'b list
+  val rev_map : ('a -> 'b) -> 'a list -> 'b list
+  val fold_left : ('a -> 'b -> 'a) -> 'a -> 'b list -> 'a
+  val fold_right : ('a -> 'b -> 'b) -> 'a list -> 'b -> 'b
+  val iter2 : ('a -> 'b -> unit) -> 'a list -> 'b list -> unit
+  val map2 : ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
+  val rev_map2 : ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
+  val fold_left2 : ('a -> 'b -> 'c -> 'a) -> 'a -> 'b list -> 'c list -> 'a
+  val fold_right2 : ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
+  val for_all : ('a -> bool) -> 'a list -> bool
+  val exists : ('a -> bool) -> 'a list -> bool
+  val for_all2 : ('a -> 'b -> bool) -> 'a list -> 'b list -> bool
+  val exists2 : ('a -> 'b -> bool) -> 'a list -> 'b list -> bool
+  val mem : 'a -> 'a list -> bool
+  val memq : 'a -> 'a list -> bool
+  val find : ('a -> bool) -> 'a list -> 'a
+  val filter : ('a -> bool) -> 'a list -> 'a list
+  val find_all : ('a -> bool) -> 'a list -> 'a list
+  val partition : ('a -> bool) -> 'a list -> 'a list * 'a list
+  val assoc : 'a -> ('a * 'b) list -> 'b
+  val assq : 'a -> ('a * 'b) list -> 'b
+  val mem_assoc : 'a -> ('a * 'b) list -> bool
+  val mem_assq : 'a -> ('a * 'b) list -> bool
+  val remove_assoc : 'a -> ('a * 'b) list -> ('a * 'b) list
+  val remove_assq : 'a -> ('a * 'b) list -> ('a * 'b) list
+  val split : ('a * 'b) list -> 'a list * 'b list
+  val combine : 'a list -> 'b list -> ('a * 'b) list
+  val sort : ('a -> 'a -> int) -> 'a list -> 'a list
+  val stable_sort : ('a -> 'a -> int) -> 'a list -> 'a list
+  val fast_sort : ('a -> 'a -> int) -> 'a list -> 'a list
+  val merge : ('a -> 'a -> int) -> 'a list -> 'a list -> 'a list
+end = struct include List end
+
+(* Allow only safe functions from String. *)
+module String : sig
+  external length : string -> int = "%string_length"
+  external get : string -> int -> char = "%string_safe_get"
+  external set : string -> int -> char -> unit = "%string_safe_set"
+  external create : int -> string = "caml_create_string"
+  val make : int -> char -> string
+  val copy : string -> string
+  val sub : string -> int -> int -> string
+  val fill : string -> int -> int -> char -> unit
+  val blit : string -> int -> string -> int -> int -> unit
+  val concat : string -> string list -> string
+  val iter : (char -> unit) -> string -> unit
+  val escaped : string -> string
+  val index : string -> char -> int
+  val rindex : string -> char -> int
+  val index_from : string -> int -> char -> int
+  val rindex_from : string -> int -> char -> int
+  val contains : string -> char -> bool
+  val contains_from : string -> int -> char -> bool
+  val rcontains_from : string -> int -> char -> bool
+  val uppercase : string -> string
+  val lowercase : string -> string
+  val capitalize : string -> string
+  val uncapitalize : string -> string
+  type t = string
+  val compare: t -> t -> int
+end = struct include String end
+
+(* Load our custom grammar, which disables "external". *)
+
+#load "camlp4o.cma";;
+#load "./pa_noexternal.cmo";;
+
+(* Chroot and setuid to nobody.  If this fails, die. *)
+#load "unix.cma";;
+let () =
+  try
+    let pw = Unix.getpwnam "nobody" in
+    Unix.chdir "/var/local/xavierbot/chroot";
+    Unix.chroot "/var/local/xavierbot/chroot";
+    Unix.setgid pw.Unix.pw_gid;
+    Unix.setuid pw.Unix.pw_uid
+  with
+    exn ->
+      print_endline (Printexc.to_string exn);
+      exit 1
+
+(* Kill the Unix and UnixLabels modules, and exit function. *)
+module Unix = struct end
+module UnixLabels = struct end
+let exit = ()
diff --git a/init.in b/init.in
new file mode 100644
index 0000000..5dcc5ab
--- /dev/null
+++ b/init.in
@@ -0,0 +1,147 @@
+(* Initialise the toplevel environment.
+ * $Id: init.in,v 1.1 2007/06/28 19:47:26 rjones Exp $
+ * - Removes the Pervasives module and any dangerous functions.
+ * - Loads just the modules we want to give access to, and just
+ *   the functions within those modules that we want to give.
+ * - Sets up our custom camlp4 grammar which removes "external"
+ *   keyword.
+ * - Chroot to somewhere safe.
+ *)
+
+(* Remove the Pervasives module. *)
+module Pervasives = struct end;;
+
+(* Remove any unsafe imported functions. *)
+let open_out = ()
+let open_out_bin = ()
+let open_out_gen = ()
+let flush = ()
+let flush_all = ()
+let output_value = ()
+let seek_out = ()
+let close_out = ()
+let close_out_noerr = ()
+let set_binary_mode_out = ()
+
+let open_in = ()
+let open_in_bin = ()
+let open_in_gen = ()
+let input_char = ()
+let input_line = ()
+let input = ()
+let really_input = ()
+let input_byte = ()
+let input_binary_int = ()
+let input_value = ()
+let seek_in = ()
+let pos_in = ()
+let in_channel_length = ()
+let close_in = ()
+let close_in_noerr = ()
+let set_binary_mode_in = ()
+
+module LargeFile = struct end;;
+
+(* let exit = () -- do this later *)
+let at_exit = ()
+let valid_float_lexem = ()
+let unsafe_really_input = ()
+let do_at_exit = ()
+
+(* Allow the List function. *)
+module List : sig
+  val length : 'a list -> int
+  val hd : 'a list -> 'a
+  val tl : 'a list -> 'a list
+  val nth : 'a list -> int -> 'a
+  val rev : 'a list -> 'a list
+  val append : 'a list -> 'a list -> 'a list
+  val rev_append : 'a list -> 'a list -> 'a list
+  val concat : 'a list list -> 'a list
+  val flatten : 'a list list -> 'a list
+  val iter : ('a -> unit) -> 'a list -> unit
+  val map : ('a -> 'b) -> 'a list -> 'b list
+  val rev_map : ('a -> 'b) -> 'a list -> 'b list
+  val fold_left : ('a -> 'b -> 'a) -> 'a -> 'b list -> 'a
+  val fold_right : ('a -> 'b -> 'b) -> 'a list -> 'b -> 'b
+  val iter2 : ('a -> 'b -> unit) -> 'a list -> 'b list -> unit
+  val map2 : ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
+  val rev_map2 : ('a -> 'b -> 'c) -> 'a list -> 'b list -> 'c list
+  val fold_left2 : ('a -> 'b -> 'c -> 'a) -> 'a -> 'b list -> 'c list -> 'a
+  val fold_right2 : ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c
+  val for_all : ('a -> bool) -> 'a list -> bool
+  val exists : ('a -> bool) -> 'a list -> bool
+  val for_all2 : ('a -> 'b -> bool) -> 'a list -> 'b list -> bool
+  val exists2 : ('a -> 'b -> bool) -> 'a list -> 'b list -> bool
+  val mem : 'a -> 'a list -> bool
+  val memq : 'a -> 'a list -> bool
+  val find : ('a -> bool) -> 'a list -> 'a
+  val filter : ('a -> bool) -> 'a list -> 'a list
+  val find_all : ('a -> bool) -> 'a list -> 'a list
+  val partition : ('a -> bool) -> 'a list -> 'a list * 'a list
+  val assoc : 'a -> ('a * 'b) list -> 'b
+  val assq : 'a -> ('a * 'b) list -> 'b
+  val mem_assoc : 'a -> ('a * 'b) list -> bool
+  val mem_assq : 'a -> ('a * 'b) list -> bool
+  val remove_assoc : 'a -> ('a * 'b) list -> ('a * 'b) list
+  val remove_assq : 'a -> ('a * 'b) list -> ('a * 'b) list
+  val split : ('a * 'b) list -> 'a list * 'b list
+  val combine : 'a list -> 'b list -> ('a * 'b) list
+  val sort : ('a -> 'a -> int) -> 'a list -> 'a list
+  val stable_sort : ('a -> 'a -> int) -> 'a list -> 'a list
+  val fast_sort : ('a -> 'a -> int) -> 'a list -> 'a list
+  val merge : ('a -> 'a -> int) -> 'a list -> 'a list -> 'a list
+end = struct include List end
+
+(* Allow only safe functions from String. *)
+module String : sig
+  external length : string -> int = "%string_length"
+  external get : string -> int -> char = "%string_safe_get"
+  external set : string -> int -> char -> unit = "%string_safe_set"
+  external create : int -> string = "caml_create_string"
+  val make : int -> char -> string
+  val copy : string -> string
+  val sub : string -> int -> int -> string
+  val fill : string -> int -> int -> char -> unit
+  val blit : string -> int -> string -> int -> int -> unit
+  val concat : string -> string list -> string
+  val iter : (char -> unit) -> string -> unit
+  val escaped : string -> string
+  val index : string -> char -> int
+  val rindex : string -> char -> int
+  val index_from : string -> int -> char -> int
+  val rindex_from : string -> int -> char -> int
+  val contains : string -> char -> bool
+  val contains_from : string -> int -> char -> bool
+  val rcontains_from : string -> int -> char -> bool
+  val uppercase : string -> string
+  val lowercase : string -> string
+  val capitalize : string -> string
+  val uncapitalize : string -> string
+  type t = string
+  val compare: t -> t -> int
+end = struct include String end
+
+(* Load our custom grammar, which disables "external". *)
+
+#load "camlp4o.cma";;
+#load "./pa_noexternal.cmo";;
+
+(* Chroot and setuid to nobody.  If this fails, die. *)
+#load "unix.cma";;
+let () =
+  try
+    let pw = Unix.getpwnam "@OCAMLUSER@" in
+    Unix.chdir "@CHROOTDIR@";
+    Unix.chroot "@CHROOTDIR@";
+    Unix.setgid pw.Unix.pw_gid;
+    Unix.setuid pw.Unix.pw_uid
+  with
+    exn ->
+      print_endline (Printexc.to_string exn);
+      exit 1
+
+(* Kill the Unix and UnixLabels modules, and exit function. *)
+module Unix = struct end
+module UnixLabels = struct end
+let exit = ()
diff --git a/ocamlbotwrapper.c b/ocamlbotwrapper.c
new file mode 100644
index 0000000..d7ad40d
--- /dev/null
+++ b/ocamlbotwrapper.c
@@ -0,0 +1,25 @@
+/* -*- C -*-
+ * $Id: ocamlbotwrapper.c,v 1.1 2007/06/28 19:47:26 rjones Exp $
+ * SUID wrapper around ocaml program.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+
+const char *new_environ[] = {
+  "PATH=/usr/bin",
+  NULL
+};
+
+int
+main ()
+{
+  /* Run the ocaml program with the correct args. */
+  execle ("/usr/bin/ocaml", "@OCAML@", "-init", "xavierbot/share/xavierbot/init", NULL, new_environ);
+
+  /* If it failed, die with an error message. */
+  perror ("/usr/bin/ocaml");
+  exit (1);
+}
diff --git a/ocamlbotwrapper.c.in b/ocamlbotwrapper.c.in
new file mode 100644
index 0000000..76aa4cd
--- /dev/null
+++ b/ocamlbotwrapper.c.in
@@ -0,0 +1,25 @@
+/* -*- C -*-
+ * $Id: ocamlbotwrapper.c.in,v 1.1 2007/06/28 19:47:26 rjones Exp $
+ * SUID wrapper around ocaml program.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+
+const char *new_environ[] = {
+  "PATH=/usr/bin",
+  NULL
+};
+
+int
+main ()
+{
+  /* Run the ocaml program with the correct args. */
+  execle ("@OCAML@", "@OCAML@", "-init", "@INITSCRIPT@", NULL, new_environ);
+
+  /* If it failed, die with an error message. */
+  perror ("@OCAML@");
+  exit (1);
+}
diff --git a/pa_noexternal.ml b/pa_noexternal.ml
new file mode 100644
index 0000000..07723dd
--- /dev/null
+++ b/pa_noexternal.ml
@@ -0,0 +1,21 @@
+(* Delete the "external" word from the language.
+ * $Id: pa_noexternal.ml,v 1.1 2007/06/28 19:47:26 rjones Exp $
+ *)
+
+open Printf
+open Camlp4.PreCast
+open Syntax
+
+(*DELETE_RULE Gram
+  str_item: "external"; LIDENT; ":"; ctyp; "="; LIST0 [ STRING ]
+END;;*)
+
+(* DELETE_RULE above didn't work.  Easier just to overwrite the rule. *)
+EXTEND Gram
+  GLOBAL: str_item;
+
+  str_item: LEVEL "top" [
+    [ "external"; LIDENT; ":"; ctyp; "="; LIST0 [ STRING ] ->
+	<:str_item< print_endline "'external' keyword disabled" >> ]
+  ];
+END;;
diff --git a/xavierbot.pl b/xavierbot.pl
index 6b058e0..f79310d 100755
--- a/xavierbot.pl
+++ b/xavierbot.pl
@@ -2,7 +2,7 @@
 # xavierbot : an OCaml interpreter IRC bot.
 # By Richard W.M. Jones <rich@annexia.org>.
 # This code is in the Public Domain.
-# $Id: xavierbot.pl,v 1.2 2007/06/28 16:22:33 rjones Exp $
+# $Id: xavierbot.pl,v 1.3 2007/06/28 19:47:26 rjones Exp $
 
 use strict;
 
@@ -13,6 +13,7 @@ use POE qw(Component::IRC);
 
 my $nick = "xavierbot";
 my $ircname = "Xavierbot";		# Printable name.
+#my $server = "chat.freenode.net";
 my $server = "devserv.devel.redhat.com";
 my $port = 6667;
 
@@ -35,19 +36,28 @@ POE::Session->create (
   heap => { irc => $irc },
 );
 
-$poe_kernel->run ();
+POE::Wheel::Run->new (
+  Program => [ "/usr/local/sbin/ocamlbotwrapper" ],
+  StdoutEvent => 'stdout_event',
+  StderrEvent => 'stdout_event',
+);
+
+POE::Kernel->run ();
 exit 0;
 
-sub _start {
+sub _start
+{
     my ($kernel, $heap) = @_[KERNEL,HEAP];
 
     my $irc_session = $heap->{irc}->session_id ();
     $kernel->post ($irc_session => register => "all");
     $kernel->post ($irc_session => connect => { });
+
     undef;
 }
 
-sub irc_001 {
+sub irc_001
+{
     my ($kernel, $sender) = @_[KERNEL,SENDER];
 
     my $poco_object = $sender->get_heap ();
@@ -57,7 +67,8 @@ sub irc_001 {
     undef;
 }
 
-sub irc_public {
+sub irc_public
+{
     my ($kernel, $sender, $who, $where, $what) =
 	@_[KERNEL,SENDER,ARG0,ARG1,ARG2];
     my $nick = (split /!/, $who)[0];
@@ -71,7 +82,8 @@ sub irc_public {
     undef;
 }
 
-sub _default {
+sub _default
+{
     my ($event, $args) = @_[ARG0 .. $#_];
     my @output = ("$event: ");
 
@@ -85,3 +97,13 @@ sub _default {
     print STDOUT join " ", @output, "\n";
     return 0;
 }
+
+#----------------------------------------------------------------------
+
+# Start the bot.
+
+sub stdout_event
+{
+    my ($heap, $input, $wheel_id) = @_[HEAP,ARG0,ARG1];
+    print "Child said: $input\n";
+}
diff --git a/xavierbot.pl.in b/xavierbot.pl.in
new file mode 100755
index 0000000..8b97671
--- /dev/null
+++ b/xavierbot.pl.in
@@ -0,0 +1,109 @@
+#!/usr/bin/perl -wT
+# xavierbot : an OCaml interpreter IRC bot.
+# By Richard W.M. Jones <rich@annexia.org>.
+# This code is in the Public Domain.
+# $Id: xavierbot.pl.in,v 1.1 2007/06/28 19:47:26 rjones Exp $
+
+use strict;
+
+use POE qw(Component::IRC);
+
+#----------------------------------------------------------------------
+# Start of configuration.
+
+my $nick = "xavierbot";
+my $ircname = "Xavierbot";		# Printable name.
+#my $server = "chat.freenode.net";
+my $server = "devserv.devel.redhat.com";
+my $port = 6667;
+
+my @channels = ("#ocaml");
+
+# End of configuration.
+#----------------------------------------------------------------------
+
+my $irc = POE::Component::IRC->spawn (
+      nick => $nick,
+      ircname => $ircname,
+      server => $server,
+      port => $port,
+  ) or die "POE::Component::IRC->spawn failed: $!";
+
+POE::Session->create (
+  package_states => [
+    main => [ qw(_default _start irc_001 irc_public) ],
+  ],
+  heap => { irc => $irc },
+);
+
+POE::Wheel::Run->new (
+  Program => [ "@WRAPPER@" ],
+  StdoutEvent => 'stdout_event',
+  StderrEvent => 'stdout_event',
+);
+
+POE::Kernel->run ();
+exit 0;
+
+sub _start
+{
+    my ($kernel, $heap) = @_[KERNEL,HEAP];
+
+    my $irc_session = $heap->{irc}->session_id ();
+    $kernel->post ($irc_session => register => "all");
+    $kernel->post ($irc_session => connect => { });
+
+    undef;
+}
+
+sub irc_001
+{
+    my ($kernel, $sender) = @_[KERNEL,SENDER];
+
+    my $poco_object = $sender->get_heap ();
+    print "Connected to ", $poco_object->server_name (), "\n";
+
+    $kernel->post ($sender => join => $_ ) for @channels;
+    undef;
+}
+
+sub irc_public
+{
+    my ($kernel, $sender, $who, $where, $what) =
+	@_[KERNEL,SENDER,ARG0,ARG1,ARG2];
+    my $nick = (split /!/, $who)[0];
+    my $channel = $where->[0];
+
+    print "got: $what\n";
+    if (my ($rot13) = $what =~ /^rot13 (.+)/) {
+	$rot13 =~ tr[a-zA-Z][n-za-mN-ZA-M];
+	$kernel->post ($sender => privmsg => $channel => "$nick: $rot13");
+    }
+    undef;
+}
+
+sub _default
+{
+    my ($event, $args) = @_[ARG0 .. $#_];
+    my @output = ("$event: ");
+
+    foreach my $arg (@$args) {
+	if (ref ($arg) eq "ARRAY") {
+	    push @output, "[" . join (" ,", @$arg) . "]";
+	} else {
+	    push @output, "'$arg'";
+	}
+    }
+    print STDOUT join " ", @output, "\n";
+    return 0;
+}
+
+#----------------------------------------------------------------------
+
+# Start the bot.
+
+sub stdout_event
+{
+    my ($heap, $input, $wheel_id) = @_[HEAP,ARG0,ARG1];
+    print "Child said: $input\n";
+}