#!/bin/bash

# Copyright (C) 2011 GRNET S.A.
#
# 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; either version 2 of the License, or
# (at your option) any later version.
#
# 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, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
# 02110-1301, USA.

set -e
set -o pipefail
set -o errtrace

. @osdir@/common.sh

usage() {
    local rc="$1"

    cat <<EOF

Usage: $0 [options]

This script runs multistrap and creates a small Debian image populated with
the snf-image-helper package. This image is needed for ganeti's \`snf-image'
guest OS type to work.

OPTIONS:
    -d DIRECTORY
        Use this directory to host the created files, instead of the default
        [default: $HELPER_DIR]

    -h  Print this message

    -p PACKAGE
        Install this deb package in the helper image, instead of the default

    -y  Assume Yes to all queries and do not prompt

EOF

    exit "$rc"
}

while getopts "d:hp:y" opt; do
    case $opt in
        d) HELPER_DIR="$OPTARG"
            ;;
        h) usage 0
            ;;
        p) HELPER_PKG="$OPTARG"
            ;;
        y) NO_PROMPT="yes"
            ;;
        ?) log_error "Use \`-h' for help"; exit 1
            ;;
    esac
done

echo
echo "This is the helper image creation script for snf-image."
echo "If you don't know what to do, use \`-h'."
echo

if [ ! -d "$HELPER_DIR" -o ! -w "$HELPER_DIR" ]; then
    log_error "Helper directory \`$HELPER_DIR' does not exist or the script" \
    "has no write permission on it."
    exit 1
fi

if [ ! -e "$MULTISTRAP_CONFIG" ]; then
    log_error "Multistrap configuration file: \`$MULTISTRAP_CONFIG' does not" \
    "exist or is not readable by the script."
    exit 1
fi

cat >&1 <<EOF
This program will overwrite the following files if present:
  \`$HELPER_DIR/initrd'
  \`$HELPER_DIR/kernel'
  \`$HELPER_DIR/image'
  \`$HELPER_DIR/packages'
EOF

while [[ 1 ]]; do
    echo -n "Do you want to continue [y/N]? "
    if [ "x$NO_PROMPT" = "xyes" ]; then
        echo "y";
        break;
    fi

    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.XXXXXX")
add_cleanup rm -f "$helper_img"
dd if=/dev/zero of="$helper_img" bs=1M count="$HELPER_SIZE" &> /dev/null
echo "done"

echo "Creating partitions..."
blockdev=$("$LOSETUP" -sf $helper_img)
add_cleanup "$LOSETUP" -d "$blockdev"

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

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

root_dev=$(map_disk0 "$blockdev")-1
add_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'

root_uuid=$(blkid -s UUID -o value "$root_dev")

target=$(mktemp -d)
add_cleanup rmdir "$target"

mount "$root_dev" "$target"
add_cleanup umount "$root_dev"

do_multistrap "$target"

# Save the package list
chroot "$target" dpkg-query -W  > "$HELPER_DIR/packages"

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

cat > "$target/etc/fstab" <<EOF
# /etc/fstab: static file system information.
#
# <file system>   <mount point>   <type>  <options>       <dump>  <pass>
UUID=$root_uuid         /               ext3    defaults        0       1
proc              /proc           proc    defaults        0       0
EOF

# We need this since we mount the helper VM ro
ln -sf /proc/mounts "$target/etc/mtab"

echo "done"

echo -n "Extracting kernel..."
if [ ! -L "$target/vmlinuz" -o ! -L "$target/vmlinuz" ]; then
    echo -e "\033[1;31mfailed\033[0m"
    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"

# Make sure extended globbing is enabled
shopt -s extglob

kernel=$(ls "$target"/boot/vmlinuz-+([0-9.])-+([a-z0-9])-amd64)
initrd=$(ls "$target"/boot/initrd.img-+([0-9.])-+([a-z0-9])-amd64)

echo "Moving $(basename "$kernel") and $(basename "$initrd") to \`$HELPER_DIR'"
cp "$kernel" "$initrd" "$HELPER_DIR"

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

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

pkg_installed=$(grep snf-image-helper "$HELPER_DIR/packages" > /dev/null && echo yes)

if [ -z "$HELPER_PKG" -a -z "$pkg_installed" ]; then
    log_error "No helper package was specified and non was found by the apt."
    exit 1
fi

if [ -r "$HELPER_PKG" ]; then
    echo "Installing snf-image-helper pkg in the new image..."
    cp "$HELPER_PKG" "$target/tmp/"
    pkg_name=$(basename "$HELPER_PKG")
    add_cleanup rm "$target/tmp/$pkg_name"
    chroot "$target" dpkg -i "/tmp/$pkg_name" 2>&1 | sed -e 's/^/DPKG: /g'

    # Recreate package list
    chroot "$target" dpkg-query -W  > "$HELPER_DIR/packages"
else
    echo "snf-image-helper pkg was installed from the apt repository."
fi

helper_version="$(grep ^snf-image-helper[[:space:]] "$HELPER_DIR/packages" | cut -f2)"
host_version="$(dpkg-query -W -f "\${Version}\n" snf-image)"

if [ "$VERSION_CHECK" == yes -a -z "$HELPER_PKG" ]; then
    if [ "$host_version" != "$helper_version" ]; then
        log_error "snf-image version (=$host_version) and " \
            "snf-image-helper version (=$helper_version) don't match."
        exit 1
    fi
fi

mv "$helper_img" "$HELPER_DIR/image"

echo "$SNF_IMAGE_VERSION" > "$HELPER_DIR/version"

echo "Files in \`$HELPER_DIR' were updated successfully" >&2

exit 0

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