#!/usr/bin/perl -T -w
# Version 1.00
# Paul Matthews paul.matthews@cathedral.qld.edu.au

# This script will pull all users' mail adresses from your Active Directory
# and list them in the format "full.alias:  username" to form an alias 
# file that Postfix can use.
# Be sure to double-check the path to perl above.

# This requires Net::LDAP to be installed.  To install Net::LDAP, at a shell
# type "perl -MCPAN -e shell" and then "install Net::LDAP"

use Net::LDAP;
use Net::LDAP::Control::Paged;
use Net::LDAP::Constant ( "LDAP_CONTROL_PAGED" );

# Enter the path/file for the output
$VALID = "/etc/postfix/aliases";

# Enter email domain
$maildomain = "windows.server.int";

# Enter the FQDN of your Active Directory domain controllers below
$dc1="mc1.windows.server.int";
$dc2="mc2.windows.server.int";

# Enter the LDAP container for your userbase.
# The syntax is CN=Users,dc=example,dc=com
# This can be found by installing the Windows 2000 Support Tools
# then running ADSI Edit.
# In ADSI Edit, expand the "Domain NC [domaincontroller1.example.com]" &
# you will see, for example, DC=example,DC=com (this is your base).
# The Users Container will be specified in the right pane as
# CN=Users depending on your schema (this is your container).
# You can double-check this by clicking "Properties" of your user
# folder in ADSI Edit and examining the "Path" value, such as:
# LDAP://domaincontroller1.example.com/CN=Users,DC=example,DC=com
# which would be $hqbase="cn=Users,dc=example,dc=com"
# Note:  You can also use just $hqbase="dc=example,dc=com"
$hqbase="cn=Users,dc=windows,dc=server,dc=int";

# Enter the username & password for a valid user in your Active Directory
# with username in the form cn=username,cn=Users,dc=example,dc=com
# Make sure the user's password does not expire.  Note that this user
# does not require any special privileges.
# You can double-check this by clicking "Properties" of your user in
# ADSI Edit and examining the "Path" value, such as:
# LDAP://domaincontroller1.example.com/CN=user,CN=Users,DC=example,DC=com
# which would be $user="cn=user,cn=Users,dc=example,dc=com"
# Note: You can also use the UPN login: "user\@example.com"
$user="cn=moodleuser,cn=Users,dc=windows,dc=server,dc=int";
$passwd="Moodle";

# Connecting to Active Directory domain controllers
$noldapserver=0;
$ldap = Net::LDAP->new($dc1) or
   $noldapserver=1;
if ($noldapserver == 1)  {
   $ldap = Net::LDAP->new($dc2) or
      die "Error connecting to specified domain controllers $@ \n";
}

$mesg = $ldap->bind ( dn => $user,
                     password =>$passwd);
if ( $mesg->code()) {
    die ("error:", $mesg->code(),"\n","error name: ",$mesg->error_name(),

        "\n", "error text: ",$mesg->error_text(),"\n");
}

# How many LDAP query results to grab for each paged round
# Set to under 1000 for Active Directory
$page = Net::LDAP::Control::Paged->new( size => 990 );

@args = ( base     => $hqbase,
         filter => "(&(sAMAccountName=*)(mail=*))",
         control  => [ $page ],
         attrs  => "sAMAccountName"
);

my $cookie;
while(1) {
  # Perform search
  my $mesg = $ldap->search( @args );

  foreach my $entry ( $mesg->entries ){
    $username = $entry->get_value("sAMAccountName");
    $alias = $entry->get_value("mail");
    $alias =~ s/.$maildomain/:/i;
    $aliasentry = $alias . "   $username";
    push(@valid, ($aliasentry."\n")); 
    }
  # Only continue on LDAP_SUCCESS
  $mesg->code and last;

  # Get cookie from paged control
  my($resp)  = $mesg->control( LDAP_CONTROL_PAGED ) or last;
  $cookie    = $resp->cookie or last;

  # Set cookie in paged control
  $page->cookie($cookie);
}

if ($cookie) {
  # We had an abnormal exit, so let the server know we do not want any more
  $page->cookie($cookie);
  $page->size(0);
  $ldap->search( @args );
  # Also would be a good idea to die unhappily and inform OP at this point
     die("LDAP query unsuccessful");
}
# Only write the file once the query is successful
open VALID, ">$VALID" or die "CANNOT OPEN $VALID $!";
print VALID @valid;

close VALID;