#!/bin/sh

#
# Script to build a kernel module in /tmp. Useful if the module sources
# are installed in read-only directory.
#
# Copyright (C) 2007-2015 Oracle Corporation
#
# This file is part of VirtualBox Open Source Edition (OSE), as
# available from http://www.virtualbox.org. This file is free software;
# you can redistribute it and/or modify it under the terms of the GNU
# General Public License (GPL) as published by the Free Software
# Foundation, in version 2 as it comes in the "COPYING" file of the
# VirtualBox OSE distribution. VirtualBox OSE is distributed in the
# hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
#

# find a unique temp directory
num=0
while true; do
  tmpdir="/tmp/vbox.$num"
  if mkdir -m 0755 "$tmpdir" 2> /dev/null; then
    break
  fi
  num=`expr $num + 1`
  if  [ $num -gt 200 ]; then
    echo "Could not find a valid tmp directory"
    exit 1
  fi
done

# Guest optimal number of make jobs.
MAKE_JOBS=`grep vendor_id /proc/cpuinfo | wc -l`
if [ "${MAKE_JOBS}" -le "0" ]; then MAKE_JOBS=1; fi

# Parse our arguments, anything we don't grok is for make.
while true; do
    if [ "$1" = "--save-module-symvers" ]; then
      shift
      SAVE_MOD_SYMVERS="$1"
      shift
    elif [ "$1" = "--use-module-symvers" ]; then
      shift
      USE_MOD_SYMVERS="$1"
      shift
    elif [ "$1" = "--module-source" ]; then
      shift
      MODULE_SOURCE="$1"
      shift
    else
      break
    fi
done

# copy
if [ -n "$MODULE_SOURCE" ]; then
  cp -a "$MODULE_SOURCE"/* $tmpdir/
else
  cp -a ${0%/*}/* $tmpdir/
fi
if [ -n "$USE_MOD_SYMVERS" ]; then
  cp $USE_MOD_SYMVERS $tmpdir/Module.symvers
fi

# make, cleanup if success
cd "$tmpdir"
if make "-j${MAKE_JOBS}" "$@"; then
  if [ -n "$SAVE_MOD_SYMVERS" ]; then
    if [ -f Module.symvers ]; then
      cp -f Module.symvers $SAVE_MOD_SYMVERS
    else
      cat /dev/null > $SAVE_MOD_SYMVERS
    fi
  fi
  rm -rf $tmpdir
  exit 0
fi

# failure
rm -rf $tmpdir
exit 1