#! /bin/sh -e

# grub-install helper script for lupin. This script will upgrade
# the grub bootloader installed on the host (wubildr).
#
# Copyright (C) Agostino Russo
#
# Lupin is free software; you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as
# published by the Free Software Foundation; either version 2.1 of
# the License, or (at your option) any later version.
#
# Lupin 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 Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

# Look for wubildr on all partitions of BIOS-accessible disk devices.
# We can safely ignore the hibernation case here, because the Windows boot
# loader boots straight into Windows if Windows was hibernated.
find_wubildr () {
    local partitions=
    for disk in $(grub-mkdevicemap -m - | cut -f2); do
        disk="$(readlink -f "$disk")" || continue
        sysdisk="/sys$(udevadm info -q path -n "$disk" 2>/dev/null)" || continue
        for syspartition in "$sysdisk"/*[0-9]; do
            [ -d "$syspartition" ] || continue
            partition="/dev/$(udevadm info -q name -p "$syspartition" 2>/dev/null)" || continue
            fs="$(grub-probe -t fs -d "$partition" 2>/dev/null)" || continue
            [ "$fs" = fat ] || [ "$fs" = ntfs ] || continue
            if [ "$(grub-fstest "$partition" ls /wubildr 2>/dev/null)" ]; then
                partitions="${partitions:+$partitions }$partition"
            fi
        done
    done
    echo "$partitions"
}

parse_proc_mounts () {
    while read -r line; do
        set -- $line
        printf '%s %s %s\n' "$(readlink -f "$1")" "$2" "$3"
    done
}

unescape_mount () {
    printf %s "$1" | \
        sed 's/\\011/   /g; s/\\012/\n/g; s/\\040/ /g; s/\\134/\\/g'
}

prefix=
test_only=false

for option in "$@"; do
    case "$option" in
    --prefix=*)
        prefix=`echo "$option" | sed 's/--prefix=//'` ;;
    --test)
	test_only=: ;;
    esac
done

GRUB_DEVICE_BOOT="`grub-probe --target=device /boot`"
case ${GRUB_DEVICE_BOOT} in
  /dev/loop/*|/dev/loop[0-9])
    loop_file=`losetup ${GRUB_DEVICE_BOOT} | sed -e "s/^[^(]*(\([^)]\+\)).*/\1/"`
  ;;
esac

# Is /boot loop-mounted from a file on another filesystem?
if [ "x${loop_file}" = x ] || [ ! -f "${loop_file}" ]; then
  exit 1
fi

mtpt="${loop_file%/*}"
while [ -n "$mtpt" ]; do
    while read DEV MTPT FSTYPE OPTS REST; do
        if [ "$MTPT" = "$mtpt" ]; then
            loop_file=${loop_file#$MTPT}
            host_mountpoint=$MTPT
            break
        fi
    done < /proc/mounts
    mtpt="${mtpt%/*}"
    [ -z "$host_mountpoint" ] || break
done

if [ "x${host_mountpoint}" = x ]; then
    exit 1
fi

target="${host_mountpoint}/wubildr"

if $test_only; then
    if [ -f "$target" ]; then
        # Found on this partition
        exit 0
    elif [ "$(find_wubildr)" ]; then
        # Found on some other partition
        exit 0
    else
        # Not found
        exit 1
    fi
fi

wubildr_partitions="$(find_wubildr)"

if [ ! -f "$target" ] && [ -z "$wubildr_partitions" ]; then
    exit 1
fi

# TODO You might want to have this as a proper file somewhere in /usr/share
tmp="$(mktemp -dt)"
echo 'normal (memdisk)/wubildr.cfg' > "$tmp/wubildr-bootstrap.cfg"
cat << EOF > "$tmp/wubildr.cfg"
set show_panic_message=true
if search -s -f -n $loop_file; then
    if loopback loop0 $loop_file; then
        set root=(loop0)
        if [ -e /boot/grub/grub.cfg ]; then
            set prefix=(loop0)/boot/grub
            if configfile /boot/grub/grub.cfg; then
                set show_panic_message=false
            fi
        elif [ -e /grub/grub.cfg ]; then
                set prefix=(loop0)/grub
                if configfile /grub/grub.cfg; then
                    set show_panic_message=false
                fi
	else
		if search -s -f -n /ubuntu/install/wubildr-disk.cfg; then
			if configfile /ubuntu/install/wubildr-disk.cfg; then
				set show_panic_message=false
			fi
		fi
        fi
    fi
fi
if [ \${show_panic_message} = true ]; then
    echo "It is not possible to boot from the Ubuntu image."
    echo "The Windows partition might be corrupted."
    echo "Please reboot into Windows and run: chkdsk /r"
    echo "Then try again."
fi
EOF
(cd "$tmp" && tar cf wubildr.tar wubildr.cfg)

# Watch the modules order!
modules=" \
    biosdisk part_msdos part_gpt fat ntfs ext2 ntfscomp iso9660 loopback \
    search linux boot echo test gzio normal memdisk tar probe configfile"

# Ensure errors pass through the pipeline.
s="$( ((grub-mkimage -O i386-pc ${prefix:+--prefix="$prefix"} -c "$tmp/wubildr-bootstrap.cfg" -m "$tmp/wubildr.tar" $modules -o "$tmp/wubildro"; echo $? >&3; cat "$tmp/wubildro" 2>&3) | cat /usr/lib/grub/i386-pc/lnxboot.img - > "$tmp/wubildr") 3>&1)"; [ "$s" = 0 ]

if [ -f "$target" ]; then
    cp -af "$tmp/wubildr" "$target.new"
    mv -f "$target.new" "$target"
fi

grep ^/dev/ /proc/mounts | parse_proc_mounts >"$tmp/mounted-map"
mkdir -p "$tmp/mnt"
for partition in $wubildr_partitions; do
    if grep -q "^$partition " "$tmp/mounted-map"; then
        mpoint="$(grep "^$partition " "$tmp/mounted-map" | head -n1 | cut -d' ' -f2)"
        mpoint="$(unescape_mount "$mpoint")"
        if [ "$mpoint" = /host ]; then
            continue
        fi
    else
        mount "$partition" "$tmp/mnt" 2>/dev/null || continue
        mpoint="$tmp/mnt"
    fi
    if [ -f "$mpoint/wubildr" ]; then
        cp -af "$tmp/wubildr" "$mpoint/wubildr.new"
        mv -f "$mpoint/wubildr.new" "$mpoint/wubildr"
    fi
    if ! grep -q "^$partition " "$tmp/mounted-map"; then
        umount "$tmp/mnt" || true
    fi
done

rm -rf --one-file-system "$tmp" || true