#!/bin/sh
# $Id: build_in_tmp $
## @file
# Script to build a kernel module in /tmp.
#
# Useful if the module sources are installed in read-only directory.
#

#
# Copyright (C) 2007-2023 Oracle and/or its affiliates.
#
# This file is part of VirtualBox base platform packages, as
# available from https://www.virtualbox.org.
#
# 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, in version 3 of the
# License.
#
# 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, see <https://www.gnu.org/licenses>.
#
# The contents of this file may alternatively be used under the terms
# of the Common Development and Distribution License Version 1.0
# (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
# in the VirtualBox distribution, in which case the provisions of the
# CDDL are applicable instead of those of the GPL.
#
# You may elect to license modified versions of this file under the
# terms and conditions of either the GPL or the CDDL or both.
#
# SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
#

# 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 $tmpdir/Module.symvers
  MAKE_EXTRAOPTS="KBUILD_EXTRA_SYMBOLS=$tmpdir/Module.symvers"
fi

# make, cleanup if success
cd "$tmpdir"
if make CONFIG_MODULE_COMPRESS_GZIP= CONFIG_MODULE_COMPRESS_XZ= CONFIG_MODULE_COMPRESS_ZSTD= "-j`echo ${MAKE_JOBS}`" "$@" ${MAKE_EXTRAOPTS}; then  # strip leading space from "MAKE_JOBS"
  if [ -n "$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