#!/usr/bin/perl -w
#-d:DProf
#
# Copyright (C) 2000, 2001 Bob McElrath.
# See the file COPYING for redistribution and modification terms.
#
#    This program is free software; you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation; either version 2 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program; if not, write to the Free Software
#    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

package FilterProxy;
use vars qw($HOME $VERSION $CONFIG @MODULES $HOSTNAME $LISTEN_PORT $agent $client);

# Do some things to make Taint happy:
delete @ENV{qw(IFS CDPATH ENV BASH_ENV)};   # Make %ENV safer
$ENV{PATH} = '/bin:/usr/bin:/usr/local/bin';# Set a reasonable path

# Place configuration here

my($NAME, $CONFIG_FILE);
BEGIN {
  chomp($HOSTNAME  = `hostname`);                  # change this for multi-homed hosts.
  $LISTEN_PORT     = 8888;                         # Is also a command-line option
  $VERSION         = "0.30";
  $NAME            = "FilterProxy \$Revision: 0.35 $VERSION \$";
  chomp($HOME      = `pwd`);                       # change if necessary (needs absolute paths)
  if($HOME =~ m{([-_A-Za-z0-9./]+)}) {             # untaint $HOME
    $HOME = $1;
  }
  $CONFIG_FILE     = $ENV{FILTERPROXYCONF} || $HOME . "/FilterProxy.conf";  # should be an option
  push(@INC, $HOME . "/FilterProxy");              # add my home to perl's include path list
  use lib ".";                                     # Only this works with taint on...
}

# End configuration.  You shouldn't have to change anything below this line.
#=============================================================================#
# FIXME Uploaded data (forms) broken for large/streaming uploads (who cares?)
# FIXME Large compressable content will be downloaded in its entireity first -- possible
#       client timeout.  Should compress as a stream while feeding to client.

use strict;
no strict 'subs';
no strict 'refs';
use POSIX qw(:sys_wait_h :signal_h setsid setpgid setuid setgid); # part of perl
use sigtrap qw(stack-trace error-signals);
use Carp qw(cluck croak confess);                   # part of perl
use Config;                                         # part of perl
use File::stat;                                     # part of perl
use CGI;                                            # part of perl
use Getopt::Std;                                    # part of perl
use Data::Dumper;                                   # part of perl
$Data::Dumper::Indent = 1;
use HTTP::Daemon;                                   # in Bundle::LWP (libwww)
use HTTP::Status;                                   # in Bundle::LWP (perl-libwww-perl rpm)
use URI::Escape;                                    # URI module     (perl-URI)
use LWP::UserAgent;                                 # in Bundle::LWP
use LWP::MediaTypes;                                # in Bundle::LWP
#use LWP::Debug qw(+debug +trace +conns);
use Time::HiRes;                                    # grab this from CPAN
use HTML::Mason;                                    # grab this from CPAN

# subclass UserAgent to disallow redirects.
@UserAgent::ISA = qw /LWP::UserAgent/;
sub UserAgent::redirect_ok {0;}
sub UserAgent::get_basic_credentials { 
    return ($CONFIG->{http_proxy_username}, $CONFIG->{http_proxy_password}); 
}

# Configuration saved to config file (This is only in case this info isn't
# already in the config file!)  Don't change this!  The config file overrides it!
$CONFIG = {};
$CONFIG->{filtering} = 1;    # on/off switch for the filter
$CONFIG->{info} = 1;         # log informational messages
$CONFIG->{timing} = 0;       # log timing information (how long it takes to run filters)
$CONFIG->{debug} = 0;        # log debugging messages
$CONFIG->{authenable} = 0;   # enable authentication of users by password
$CONFIG->{localhostonly} = 0;# accept connections from localhost only
$CONFIG->{logfile} = $HOME . "/FilterProxy.log";  # set to "" to disable logfile
$CONFIG->{timeout} = 300;    # wait 5 minutes before giving up on outgoing connections.
$CONFIG->{filters} = {};
$CONFIG->{http_proxy} = "";
$CONFIG->{http_proxy_username} = "";
$CONFIG->{http_proxy_password} = "";

# File scoped variables
my(%children) = ();     # keys are pids of my children
# $client;            # connection to the client
my($inreq);             # incoming request -- needs to be accessable to data_handler
my($clientprotocol);    # protocol client is using (0.9, 1.0, 1.01, 1.1)
my($send_response);     # We're going to grab the whole file, as opposed to passing it through in pieces.