#!/bin/bash -
# Copyright (C) 2009-2010 Red Hat Inc.
#
# 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., 675 Mass Ave, Cambridge, MA 02139, USA.

# Helper script which constructs the supermin appliance at runtime.

unset CDPATH

set -e

if [ $# -ne 5 ]; then
    p=`basename $0`
    echo
    echo "$p: Create supermin appliance."
    echo
    echo "Usage:"
    echo "$p sourcedir host_cpu repo kernel initrd"
    echo
    echo "This script is used by libguestfs to build the supermin appliance"
    echo "(kernel and initrd output files).  You should NOT need to run this"
    echo "program directly except if you are debugging tricky supermin"
    echo "appliance problems."
    echo
    echo "NB: The kernel and initrd parameters are OUTPUT parameters.  If"
    echo "those files exist, they are overwritten by the output."
    echo
    echo "Typical usage when debugging supermin appliance problems:"
    echo "  $p /usr/lib64/guestfs x86_64 fedora-12 /tmp/kernel /tmp/initrd"
    echo "Note: This will OVERWRITE any existing files called /tmp/kernel"
    echo "and /tmp/initrd."
    echo
    exit 1
fi

# Source directory containing the supermin input files.
sourcedir=$(cd "$1" > /dev/null; pwd)

# Host CPU and repo constants passed from the library (see:
# https://bugzilla.redhat.com/show_bug.cgi?id=558593).
host_cpu=$2
repo=$3

# Output files.
kernel="$4"
initrd="$5"

# Kernel:
# Look for the most recent kernel named vmlinuz-*.<arch>* which has a
# corresponding directory in /lib/modules/. If the architecture is x86, look
# for any x86 kernel.
#
# RHEL 5 didn't append the arch to the kernel name, so look for kernels
# without arch second.

arch=$(echo $host_cpu | sed 's/^i.86$/i?86/')
kernels=$(
    ls -1dvr /boot/vmlinuz-*.$arch* 2>/dev/null | grep -v xen ||: ;
    ls -1dvr /boot/vmlinuz-* 2>/dev/null | grep -v xen
)

if [ -z "$kernels" ]; then
    echo "$0: failed to find a suitable kernel in /boot directory" >&2
    exit 1
fi

for f in $kernels; do
    b=$(basename "$f")
    b=$(echo "$b" | sed 's,vmlinuz-,,')
    modpath="/lib/modules/$b"
    if [ -d "$modpath" ]; then
        ln -sf "$f" "$kernel"
        break
    fi
    modpath=
done

if [ -z "$modpath" ]; then
    echo "$0: failed to find a suitable kernel" >&2
    exit 1
fi

# The initrd consists of these components:
# (1) The base skeleton appliance that we constructed at build time.
#     name = initramfs.$repo.$host_cpu.supermin.img
#     format = compressed cpio
# (2) The modules from modpath which are on the module whitelist.
#     format = plain cpio
# (3) The host files which match wildcards in *.supermin.hostfiles.
#     format = plain cpio

cp "$sourcedir"/initramfs.$repo.$host_cpu.supermin.img "$initrd"

# Kernel modules (2).
exec 5<"$sourcedir"/kmod.whitelist
whitelist=
while read kmod 0<&5; do
    whitelist="$whitelist -o -name $kmod"
done
exec 5<&-

find "$modpath" \( -not -name '*.ko' $whitelist \) -a -print0 |
  cpio --quiet -o -0 -H newc >> "$initrd"

# Host files (3).

(cd / && \
  ls -1df $(
      cat "$sourcedir"/initramfs.$repo.$host_cpu.supermin.hostfiles
    ) 2>/dev/null |
  cpio -C 65536 --quiet -o -H newc ) >> "$initrd"