#!/usr/bin/perl
####################################################
# Patches the Airport Extreme driver for use in MOL
# Copyright 2005, Joseph Jezak
# Based on work by Mattias Nissler and Johannes Berg
# This file is public domain
####################################################
use strict;

my $patch = 0;

### Deal with the user's options
if ($ARGV[0] eq "--patch") {
  $patch = 1;
}
elsif ($ARGV[0] eq "--revert") {
  $patch = 0;
}
else {
  print "This program patches the AppleAirport2 driver to use PIO mode, which\n";
  print "enables usage of the Airport Extreme from within MOL.\n\n";
  print "Usage:\taepatch [--patch or --revert] [path]\n"; 
  print "  --revert\tReverts the patch and restores the driver\n";
  print "  --patch\tPatches the driver for PIO support\n\n";
  print "The optional path for the location of the kext defaults to:\n";
  print "/System/Library/Extensions/AppleAirport2.kext/Contents/MacOS/AppleAirPort2\n\n";
  print "*** PLEASE BACK UP THE DRIVER FIRST!  YOU HAVE BEEN WARNED! ***\n";
  exit();
}

### Set up the driver path
my $driver;
if($ARGV[1] eq "") {
   $driver = "/System/Library/Extensions/AppleAirport2.kext/Contents/MacOS/AppleAirPort2";
}
else {
  $driver = $ARGV[1];
}

### Open the File
open AE2, "+<".$driver or die "Can't open ".$driver."!\n"; 

### Get file size
my @ae2stat = stat AE2; 

### Find the number of times we check for PIO (so we can see if it's compatible)
$|=1;
print "Checking for compatible driver ...";
$|=0;
my $int = 0;
my @positions;
while(read (AE2, $int, 4)) {
  if ($int eq pack("CCCC", 56, 1, 0, 80)) {
    push @positions, (tell AE2) - 4; 
  }
}

### If PIO isn't supported
if($#positions + 1 != 3) {
  print "failed.\n";
  print " *** Sorry your driver does not support PIO mode.  Please try another version.\n";
}
### Patch the driver
else {
  print "ok.\n";
  seek AE2, $positions[1] + 16, 0;
  read AE2, $int, 4;
  ### Patch it
  if($patch){
    print " *** Patching the driver... ";
    if($int eq pack("CCCC",57,0,0,0)) {
	seek AE2, -4, 1;
	print AE2 pack("CCCC",57,0,0,1);
	print "done.\n";
    }
    else {
      print "failed.\n";
      print " *** Sorry, either this driver version is not supported or it's already patched!\n"; 
    }
  }
  ### Reverse the patch
  else {
    print " *** Reversing the patch... ";
    if($int eq pack("CCCC", 57,0,0,1)) {
	seek AE2, -4, 1;
	print AE2 pack("CCCC",57,0,0,0);
	print "done.\n";
    }
    else {
      print "failed.\n";
      print " *** Sorry, either this driver version is not supported or it isn't patched yet!\n"; 
    }
  }
}

### Close the driver
close AE2;