#!/usr/bin/perl
# Interchange::Link -- mod_perl 1.99/2.0 module for linking to Interchange
#
# Copyright (C) 2002-2009 Interchange Development Group
# Copyright (C) 1996-2002 Red Hat, Inc.
#
# 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., 675 Mass Ave, Cambridge, MA 02139, USA.
package Interchange::Link;
use strict;
use ModPerl::Registry;
use ModPerl::Code;
use Apache2::Const -compile => qw(DECLINED OK NOT_FOUND FORBIDDEN REDIRECT HTTP_MOVED_PERMANENTLY);
use Apache2::ServerRec ();
require Apache2::Connection;
require Apache2::RequestRec;
require Apache2::RequestIO;
require Apache2::RequestUtil;
use Socket;
$ENV{PATH} = "/bin:/usr/bin";
$ENV{IFS} = " ";
## This is what is returned when the environment returns undef
my $global_status;
=head1 NAME
Interchange::Link -- mod_perl 1.99/2.0 module for linking to Interchange
=head1 VERSION
2009-08-22
=head1 SYNOPSIS
SetHandler perl-script
PerlResponseHandler Interchange::Link
PerlOptions +GlobalRequest
PerlSetVar InterchangeServer /var/run/interchange/socket
PerlSetVar OrdinaryFileList "/foundation/images/ /foundation/dl/"
=head1 DESCRIPTION
Interchange::Link is designed to replace the vlink and tlink programs
that come with Interchange. The Interchange link protocol has been
implemented via an Apache mod_perl modules which saves us the (small) overhead
of the execution of a CGI program.
In addition, it will deliver downloadable files in a streaming fashion
without keeping Interchange open, which cuts overhead dramatically for
large downloadable files. See L.
Note that this module is not compatible with Apache 1.
=head1 PREREQUISITES
You must have mod_perl 1.99 or higher installed on your Apache. On a
Red Hat-style Linux system, it is as simple as:
rpm -i mod_perl-1.99.XX-X.rpm
service httpd restart
Installation of mod_perl will vary from system to system. Consult the
mod_perl documentation. Sometimes it is as easy as
perl -MCPAN -e 'install ModPerl::Registry'
but often it is not.
Usually you can download the package from http://perl.apache.org/ and
follow those instructions.
=head1 INSTALLATION
You must specify that Apache use mod_perl, and you must tell it where
to find the Perl modules you want to use.
On a Red Hat Linux system you might copy this file to /usr/lib/httpd/perl/
via this procedure:
mkdir -p /usr/lib/httpd/perl/Interchange
cp Link.pm /usr/lib/httpd/perl/Interchange
If you have mod_perl2 1.999_21 or earlier, you should instead do:
mkdir -p /usr/lib/httpd/perl/Interchange
cp Link.pm.mod_perl-1.999_21_and_before /usr/lib/httpd/perl/Interchange
Then you provide a startup script that tells mod_perl where its
libraries are:
cd /usr/lib/httpd/perl
echo "use lib qw(/usr/lib/httpd/perl);1;" > startup.pl
Then you can put in your /etc/httpd/conf/httpd.conf:
PerlModule Apache2
PerlRequire /usr/lib/httpd/perl/startup.pl
Finally, you specify a location like:
SetHandler perl-script
PerlResponseHandler Interchange::Link
PerlOptions +GlobalRequest
# Make sure you set SocketPerms to 0666 (or 0660 with appropriate
# setgid group ownership of the directory)
PerlSetVar InterchangeServer /var/run/interchange/socket
PerlSetVar OrdinaryFileList "/foundation/images/ /foundation/dl/"
Note: The Apache path should not contain a dot (.) or any
other characters except A-Z, a-z, 0-9 or a hyphen (-), so:
is invalid, whereas:
is valid.
The specifics of the configuration are discussed in the next section.
=head1 CONFIGURATION
The module understands directives set via the mod_perl C
directive.
=over 4
=item InterchangeServer
This specifies the way to contact the
primary and possibly additionial Interchange servers. The InterchangeServer
directive takes either a pathname to the Interchange UNIX socket or a
host:port specification if you want to use INET mode.
Normally this takes the form of:
PerlSetVar InterchangeServer /var/run/interchange/socket
Note that your file permissions for the socket file need to allow the
Apache User uid to read and write it. This usually means "SocketPerms
0666" or in interchange.cfg. You can also do "SocketPerms 0660" if you
set the group of the containing directory to the Apache Group value,
and change the directory permissions to enable the setgid bit. (That is
accomplished with "chmod g+s ".)
If you want to specify more than one so that a backup server can provide
request support in case of failure:
PerlSetVar InterchangeServer "/var/run/interchange/socket 10.1.1.1:7786"
The optional InterchangeServerBackup directive takes the same arguments,
but should obviously point to a different Interchange server than the
primary. The InterchangeServerBackup directive is only of any use if
you have multiple Interchange servers configured in a clustered environment.
If you want to randomly select from a series of clustered servers, do:
PerlSetVar InterchangeServer "10.1.1.1:7786 10.1.1.2:7786 10.1.1.3:7786"
PerlSetVar RandomServer 1
Note: The Apache path should not contain a dot (.) or any
other characters except A-Z, a-z, 0-9 or a hyphen (-), so:
is invalid, whereas:
is valid.
Example of a UNIX mode local connection:
SetHandler perl-script
PerlResponseHandler Interchange::Link
PerlSetVar InterchangeServer /opt/interchange/etc/socket
Example of INET mode local connection:
SetHandler perl-script
PerlResponseHandler Interchange::Link
PerlSetVar InterchangeServer localhost:7786
UNIX mode local primary connection and INET mode remote backup connection:
SetHandler perl-script
PerlResponseHandler Interchange::Link
PerlSetVar InterchangeServer /opt/interchange/etc/socket
PerlSetVar InterchangeServerBackup another.server.com:7786
The default if not set is C<127.0.0.1:7786>.
=item ConnectTries and ConnectRetryDelay
The ConnectTries parameter specifies the number of connection attempts to
make before giving up. ConnectRetryDelay specifies the delay, in seconds,
between each retry attempt.
The ConnectTries default is 10 and the ConnectRetryDelay default is 2 seconds.
Here is an example:
SetHandler perl-script
PerlResponseHandler Interchange::Link
PerlSetVar ConnectTries 10
PerlSetVar ConnectRetryDelay 1
=item DropRequestList
The DropRequestList allows a list of space-separated URI components
to be specified. If one of the list entries is found anywhere in the
requested URI, the request will be dropped with a 404 (not found) error,
without the request being passed to Interchange. This parameter is useful
for blocking known Microsoft IIS attacks like "Code Red", so that we don't
waste any more time processing the (bogus) requests than we have to.
SetHandler perl-script
PerlResponseHandler Interchange::Link
PerlSetVar DropRequestList "/default.ida /x.ida /cmd.exe /root.exe"
=item OrdinaryFileList
The OrdinaryFileList allows a list of space-separated URI path
components to be specified. If one of the list entries is found at the
start of any request then that request will not be passed to Interchange.
Instead, the file will be directly served by Apache. For example:
SetHandler perl-script
PerlResponseHandler Interchange::Link
PerlSetVar OrdinaryFileList "/foundation/ /interchange-5/ /robots.txt"
This will result in the following:
www.example.com/index.html (handled by Interchange)
www.example.com/ord/basket.html (handled by Interchange)
www.example.com/foundation/images/somefile.gif (served by Apache)
www.example.com/robots.txt (served by Apache)
You should add a trailing slash to directory names to prevent, for instance,
"/images/foo.gif" from being confused with the likes of "/images.html".
If OrdinaryFileList was set to "/images" then both of those requests would
be handled by Apache. If OrdinaryFileList was set to "/images/" then
"/images/foo.gif" would be handled by Apache and "/images.html" would be
handled by Interchange.
If you're using "" then you will need a dummy "index.html" file
in your VirtualHost's DocumentRoot directory to avoid permission problems
assocated with the Apache directory index creation code.
=item InterchangeScript
The InterchangeScript parameter allows the SCRIPT_NAME to be different from
the . For example:
...
The above will set the SCRIPT_NAME to "/shop".
...
PerlSetVar InterchangeScript /foo
The above will set the SCRIPT_NAME to "/foo", instead of "/shop" before
passing the request to Interchange.
The appropriate SCRIPT_NAME must be configured into the "Catalog"
directive in your interchange.cfg file.
=item FileDeliveryBase
Interchange::Link can deliver files without needing to keep Interchange
open. To do this, you set the HTTP Status: header to C.
In Interchange 5.0 or higher you can do this by putting in a page:
[deliver
status=httpd_deliver
location=directory/file.ext
type=application/octet-stream
]
The C setting determines where the file will be
relative to. While you can set it to C>, that is not recommended
as files like C could be delivered.
The default is the document root of the Apache server. To protect
files from being served directly by Apache, you can either put them
under a directory at the Interchange location, or you can use normal
Apache exclusions.
=item NoBlankLines
Set C to 1 to remove blank lines from the outputted source
code.
=back
=head1 BUGS
Send bug reports and suggestions to the Interchange users list,
.
=head1 COPYRIGHT AND LICENSE
Copyright (C) 2002-2009 Interchange Development Group
Copyright (C) 1996-2002 Red Hat, Inc.
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. You may refer to 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.
=cut
my %config;
sub setup_location {
my $r = shift;
my $s = $r->server;
my $location = $r->location;
return $config{$location} if $config{$location} && !($s->is_virtual());
#warn "Getting location $location\n";
my $c = $config{$location} = {};
$c->{InterchangeScript} = $r->dir_config('InterchangeScript') || $location;
my @OrdinaryFileList;
ORDINARY: {
my $ordstring = $r->dir_config('OrdinaryFileList')
or last ORDINARY;
@OrdinaryFileList = grep /\S/, split /\s+/, $ordstring;
for (@OrdinaryFileList) {
$_ = qr(^$_);
}
}
my @DropRequestList;
DROPREQ: {
my $dropstring = $r->dir_config('DropRequestList')
or last DROPREQ;
@DropRequestList = grep /\S/, split /\s+/, $dropstring;
for (@DropRequestList) {
$_ = qr(^$_$);
}
}
SERVPOOL: {
my $serverpool = $r->dir_config('ServerPool');
if(! $serverpool) {
$serverpool = $r->dir_config('InterchangeServer');
if($serverpool and $r->dir_config('InterchangeServerBackup')) {
$serverpool .= " " . $r->dir_config('InterchangeServerBackup');
}
}
$serverpool ||= '127.0.0.1:7786';
$serverpool =~ s/^\s+//;
$serverpool =~ s/\s+$//;
my @servpool = split /\s+/, $serverpool;
$c->{ServerPool} = \@servpool;
}
my $base = $r->dir_config('FileDeliveryBase') || $r->document_root;
$base =~ s:/*$:/: unless $base eq '/';
$c->{FileDeliveryBase} = $base;
$c->{RandomServer} = $r->dir_config('RandomServer');
$c->{ConnectTries} = $r->dir_config('ConnectTries') || 10;
$c->{ConnectRetryDelay} = $r->dir_config('ConnectRetryDelay') || 2;
$c->{DropRequestList} = \@DropRequestList if @DropRequestList;
$c->{OrdinaryFileList} = \@OrdinaryFileList if @OrdinaryFileList;
return $c;
}
my $arg;
my $env;
my $ent;
sub server_not_running {
my $r = shift;
my $msg;
warn "ALERT: Interchange server not running for $ENV{SCRIPT_NAME}\n";
$r->content_type ("text/html");
$r->print (<Service unavailable
We are temporarily out of service or may be experiencing high system demand.
Please try again soon.