#!/bin/sh

[ -z $PREPKG ] && exit 1

CONFIG=$1
FILES=$(cd $(dirname $0) ; pwd)

if [ -z "$CONFIG" -o ! -r $FILES/config/$CONFIG ]; then
  echo "specify one of the following configs:"
  ls $FILES/config/
  exit 1
fi

VERSION=$(sed -n 's,^VERSION = ,,p' Makefile)
PATCHLEVEL=$(sed -n 's,^PATCHLEVEL = ,,p' Makefile)
SUBLEVEL=$(sed -n 's,^SUBLEVEL = ,,p' Makefile)
EXTRAVERSION=$(sed -n 's,^EXTRAVERSION = ,,p' Makefile)
KERNELRELEASE=$VERSION.$PATCHLEVEL.$SUBLEVEL$EXTRAVERSION

echo "building $KERNELRELEASE for $CONFIG"

mkdir -p $PREPKG/{install,boot}/

# http://distcc.samba.org/faq.html#linux2.2
[ "$PATCHLEVEL" = "2" ] && unset MAKEJOBS

make mrproper &> make_mrproper.output || exit 1
cp $FILES/config/$CONFIG .config
make oldconfig &> make_oldconfig.output || exit 1
make dep &> make_dep.output || exit 1
make $MAKEJOBS bzImage &> make_bzImage.output || exit 1
make $MAKEJOBS modules &> make_modules.output || exit 1
make INSTALL_MOD_PATH=$PREPKG modules_install \
  &> make_modules-install.output || exit 1

# save oodles of disk space
find $PREPKG/lib/modules/ -type f -name '*.o' -exec gzip -9 {} \;

# clean up symlinks
find $PREPKG/lib/modules/ -type l -name '*.o' -printf %h\\t%f\\t%l\\n \
| while { read LDIR LFIL RFIL ; } ; do
  ( cd $LDIR ; rm -rf $LFIL )
  ( cd $LDIR ; ln -sf $RFIL.gz $LFIL.gz )
done

# regenerate modules.* to take the above into account
/sbin/depmod -ae -F System.map -b $PREPKG -r $KERNELRELEASE

cp -p System.map $PREPKG/boot/System.map-$KERNELRELEASE
ln -s System.map-$KERNELRELEASE $PREPKG/boot/System.map
cp -p .config $PREPKG/boot/config-$KERNELRELEASE
ln -s config-$KERNELRELEASE $PREPKG/boot/config
cp -p arch/i386/boot/bzImage $PREPKG/boot/vmlinuz-$KERNELRELEASE
ln -s vmlinuz-$KERNELRELEASE $PREPKG/boot/vmlinuz

cat << EOF > $PREPKG/install/doinst.sh
# A good idea whenever kernel modules are added or changed:
if [ -x sbin/depmod ]; then
  chroot . /sbin/depmod -a $KERNELRELEASE 1> /dev/null 2> /dev/null
fi

EOF

cp $FILES/slack-desc/$CONFIG $PREPKG/install/slack-desc