#!/bin/bash
# Horrific hack to bypass X version test
# Copyright 2007, Kees Cook <kees@ubuntu.com>
# License: GPLv2
set -e

SO="$1"
if [ -z "$SO" ]; then
    SO="/usr/lib/xorg/modules/drivers/fglrx_drv.so"
fi
if [ ! -e "$SO" ]; then
    echo "No such file '$SO'" >&2
    exit 1
fi
if [ ! -w "$SO" ]; then
    echo "Cannot write to '$SO' (try using sudo?)" >&2
    exit 1
fi

if [ ! -x /usr/bin/objdump ]; then
    apt-get install -y binutils
fi

function oppatch()
{
    so="$1"
    target="$2"
    op="$3"
    size="$4"

    bak="$so".pre-patch-"$target"-"$op"-"$size"
    if [ -e "$bak" ]; then
        echo "'$bak' already exists!  If you're really sure, delete it and try again" >&2
        exit 1
    fi
    echo " creating backup file '$bak' ..."
    cp "$so" "$bak"

    perl <<EOP
use IO::Handle;
print " opening '$so' ...\\n";
open(BIN,"+<$so") || die "$so: \$!\\n";
print " seeking to 0x$target ...\\n";
seek(BIN,0x$target,0) || die "seek: \$!\\n";
print " writing $op x $size ...\\n";
print BIN chr($op) x $size || die "write: \$!\\n";
close(BIN) || die "close: \$!\\n";
EOP

    echo "Patched $so at $target successfully"
}

DIS=$(mktemp -t fglrx-XXXXXX)
trap "rm -f $DIS" 0 1 2 3 4 5 6 7 8 10 11 12 13 14 15

echo "Disassembling.  One moment ..."
objdump -d "$SO" > "$DIS"

# 2D Engine (skip conditional jump)
echo "Attempting to patch 2D version test..."
for addr in $(grep atiddxMiscCheckXF86Version "$DIS" | grep call | awk '{print $1}')
do
    target=$(grep -A2 '^ *'"$addr" "$DIS" | tail -1 | grep "jg" | awk '{print $1}')
    if [ -n "$target" ]; then
        target=$(echo "$target" | cut -d: -f1)

        oppatch "$SO" "$target" 0x90 2
    fi
done

# 3D Engine (force conditional jump)
echo "Attempting to patch 3D version test..."
for addr in $(grep atiddxDriCloseScreen "$DIS" | grep call | awk '{print $1}')
do
    target=$(grep -B4 '^ *'"$addr" "$DIS" | grep "jle" | grep "atiddxDriScreenInit" | head -1 | awk '{print $1}')
    if [ -n "$target" ]; then
        target=$(echo "$target" | cut -d: -f1)

        oppatch "$SO" "$target" 0xeb 1
    fi
done