#!/bin/bash

set -e

. @osdir@/common.sh

CACHE_FILE="$HELPER_DIR/cache.tar"
ARCH=amd64
EXTRA_PKGS="linux-image-amd64,e2fsprogs,ntfs-3g,ntfsprogs,xmlstarlet,python"

if [ ! -e "$HELPER_PKG" ]; then
    log_error "Helper package \`$HELPER_PKG' not found."
    log_error "You need to provide this for the script to work"
    exit 1
fi
cat >&1 <<EOF
This program will overwrite the following files:
  \`$HELPER_DIR/initrd'
  \`$HELPER_DIR/kernel'
  \`$HELPER_DIR/image'
EOF

while [[ 1 ]]; do
    echo -n "Do you want to continue [y/N]? "
    read answer
    [ "$(echo -n "$answer" | tr [A-Z] [a-z])" = "y" ] && break
    if [ -z "$answer" -o "$(echo -n "$answer" | tr [A-Z] [a-z])" = "n" ]; then
        log_error "Abort."
        exit 1
    fi
done

rm -f "$HELPER_DIR/initrd" "$HELPER_DIR/kernel" "$HELPER_DIR/image"

echo -n "Allocating space for helper disk image..."
helper_img=$(mktemp $HELPER_DIR/image.XXXXXXXX)

dd if=/dev/zero of=$helper_img bs=1k count=400000 &> /dev/null
echo "done"

blockdev=$(losetup -sf $helper_img)
CLEANUP+=("losetup -d $blockdev")

sleep 1 # sometimes losetup returns and the device is still busy..

echo "Creating partitions..."
format_disk0 $blockdev "extdump"  2>&1 | sed -e 's/^/CFDISK: /g'

root_dev=$(map_disk0 $blockdev)-1
CLEANUP+=("unmap_disk0 $blockdev")

echo Creating and configuring filesystem...
mkfs.ext3 $root_dev 2>&1 | sed -e 's/^/MKFS.EXT3: /g'
# The helper vm should never do filesystem checks...
tune2fs -i 0 -c 0 $root_dev 2>&1 | sed -e 's/^/TUNE2FS: /g'

TMPDIR=$(mktemp -d)
CLEANUP+=("rmdir $TMPDIR")

mount $root_dev $TMPDIR
CLEANUP+=("umount $root_dev")

echo -n "Checking for cached root filesystem file \`$CACHE_FILE'..." 
if [  -f "$CACHE_FILE" ]; then
    echo "found"
    tar xf "$CACHE_FILE" -C $TMPDIR
else
    echo "not found"
    echo "Debootstraping to create a new root filesystem:"
    debootstrap --arch "$ARCH" --include $EXTRA_PKGS --variant=minbase \
	    squeeze $TMPDIR 2>&1 | sed -e 's/^/DEBOOTSTRAP: /g'

    # remove the downloaded debs, as they are no longer needed
    find "$TMPDIR/var/cache/apt/archives" -type f -name '*.deb' -print0 | \
        xargs -r0 rm -f

    TMP_CACHE=$(mktemp "${CACHE_FILE}.XXXXXX")
    tar cf "$TMP_CACHE" -C $TMPDIR .
    mv -f "$TMP_CACHE" "$CACHE_FILE"
fi

echo -n "Configuring the helper image..."
echo snf-image-helper > $TMPDIR/etc/hostname

cat > $TMPDIR/etc/fstab <<EOF
# /etc/fstab: static file system information.
#
# <file system>   <mount point>   <type>  <options>       <dump>  <pass>
/dev/sda1         /               ext3    defaults        0       1
proc              /proc           proc    defaults        0       0
EOF
echo "done"

echo -n "Extracting kernel..."
if [ ! -L "$TMPDIR/vmlinuz" -o ! -L "$TMPDIR/vmlinuz" ]; then

	log_error "vmlinuz or initrd.img link in root is missing."
	log_error "I don't know how to find a usable kernel/initrd pair."
	exit 1
fi
echo "done"

kernel=$(readlink -en $TMPDIR/vmlinuz)
initrd=$(readlink -en $TMPDIR/initrd.img)

echo "Moving $(basename $kernel) and $(basename $initrd) to $HELPER_DIR"
mv $kernel $initrd $HELPER_DIR

kernel=$(basename $kernel)
initrd=$(basename $initrd)

(cd $HELPER_DIR; ln -fs $kernel kernel; ln -fs $initrd initrd)

rm $TMPDIR/vmlinuz $TMPDIR/initrd.img

echo "Installing snf-image-helper pkg in the new image..."
cp $HELPER_PKG $TMPDIR/tmp/
pkg_name=$(basename "$HELPER_PKG")  
CLEANUP+=("rm $TMPDIR/tmp/$pkg_name")
chroot ${TMPDIR} dpkg -i /tmp/$pkg_name 2>&1 | sed -e 's/^/DPKG: /g'

cat > ${TMPDIR}/etc/rc.local <<EOF
#!/bin/sh -e
#
# rc.local
#
# This script is executed at the end of each multiuser runlevel.
# Make sure that the script will "exit 0" on success or any other
# value on error.
#
# In order to enable or disable this script just change the execution
# bits.
#
# By default this script does nothing.

/usr/bin/snf-image-helper

exit 0
EOF

chmod +x ${TMPDIR}/etc/rc.local

echo "done"

cleanup

mv $helper_img $HELPER_DIR/image

trap - EXIT

echo "Files in \`$HELPER_DIR' were updated successfully"
exit 0

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