#!/bin/bash

# mkbootdisk
#
# Written by Erik Troan <ewt@redhat.com>

pause=yes
unset kernel
device=bootcd.iso
unset verbose
unset kernelargs
unset mountopts
unset isoimage
unset realdev
size=1440
failed=0
isoimage=1
verbose=1

MOUNTDIR=`mktemp -d /tmp/mkbootdisk.XXXXXX`
PATH=/sbin:$PATH
export PATH

VERSION=1.5.2

usage () {
    cat >&2 <<EOF
usage: `basename $0` [--version] [--noprompt] [--device <devicefile>] 
       [--verbose -v] [--iso] [--kernelargs <args>] [--size <size>]  <kernel>
       (ex: `basename $0` --device /dev/fd1 2.0.31)
EOF
    exit $1
}

while [ $# -gt 0 ]; do
    case $1 in
        --device)
            shift
            device=$1
            ;;
        --kernelargs)
            shift
            kernelargs=$1
            ;;
        --help)
            usage 0
            ;;
        --iso)
            isoimage=1
            ;;
        --size)
            shift
            size=$1
            ;;
        --noprompt)
            unset pause
            ;;
        -v)
            verbose=true
            ;;
        --verbose)
            verbose=true
            ;;
        --version)
            echo "mkbootdisk: version $VERSION"
            exit 0
            ;;
        *)
            if [ -z "$kernel" ]; then
                kernel=$1
            else
                usage
            fi
            ;;
    esac

    shift
done

[ -z "$kernel" ] && usage 1

[ -d /lib/modules/$kernel ] || {
    echo "/lib/modules/$kernel is not a directory." >&2
    exit 1
}

[ -f /boot/vmlinuz-$kernel ] || {
    echo "/boot/vmlinuz-$kernel does not exist." >&2
    exit 1
}


rootdev=`awk '$1 ~ /^[^#]/ && $2 ~ /^\/$/ { print $1 ; exit }' /etc/fstab`

if [ $(echo $rootdev | cut -c1-6) = "LABEL=" ]; then
    rootlabel=$(echo $rootdev | cut -c7-)

    # whee, now we have to look through every partition looking for
    # the thing called $rootlabel, which could be raid. Ick.

    list=$(tail +3 /proc/partitions | awk '{ print $4 '} | grep '^md')
    list="$list $(tail +3 /proc/partitions | 
                        awk '{ print $4 '} | grep -v '^md')"
    rootdev=""
    for dev in $list; do
        if tune2fs -l /dev/$dev >/dev/null 2>/dev/null; then
            label=$(tune2fs -l /dev/$dev 2>/dev/null | 
                grep "Filesystem volume name" | awk '{print $4}')
            if [ "$label" = $rootlabel ]; then
                rootdev=/dev/$dev
                break
            fi
        fi
    done
fi

if [ -z "$kernelargs" -a -x /sbin/grubby -a -f /boot/grub/grub.conf ]; then
    # sed gross... this grep's for the args= line and removes the args=" and "$
    defkernel=$(grubby --default-kernel)
    if [ -n "$defkernel" ]; then
        kernelargs=$(grubby --info "$defkernel" |
                     sed -n '/^args=/{s/^args="//;s/"$//;p;}')
    fi
fi

[ -z "$rootdev" ] && {
    echo 'Cannot find root partition in /etc/fstab.' >&2
    exit 1
}

rm -rf $MOUNTDIR
mkdir $MOUNTDIR || {
    echo "Failed to create $MOUNTDIR" >&2
    exit 1
}
[ -d $MOUNTDIR ] || {
    echo "$MOUNTDIR is not a directory!" >&2
    exit 1
}

cfgfile=$MOUNTDIR/isolinux/isolinux.cfg
bootmsg=$MOUNTDIR/isolinux/boot.msg

# create an iso image; the directory is all we need
[ -n "$verbose" ] && echo -n "Installing isolinux... "
mkdir $MOUNTDIR/isolinux
cp /usr/lib/syslinux/isolinux.bin $MOUNTDIR/isolinux
[ -n "$verbose" ] && echo done


BOOTDESTDIR=$MOUNTDIR/isolinux

[ -n "$verbose" ] && echo -n "Copying /boot/vmlinuz-$kernel... "
cp -p /boot/vmlinuz-$kernel $BOOTDESTDIR/vmlinuz
[ $? = 0 ] || failed=1
[ -n "$verbose" ] && echo "done."

[ -n "$verbose" ] && echo -n "Copying /boot/initrd-$kernel.img... "
if [ -f /boot/initrd-$kernel.img ]; then
  cp -p /boot/initrd-$kernel.img $BOOTDESTDIR/initrd.img
fi
[ $? = 0 ] || failed=1
[ -n "$verbose" ] && echo "done."

[ -n "$verbose" ] && echo -n "Configuring bootloader... "

[ -f $BOOTDESTDIR/initrd.img ] && INITRDARG="initrd=initrd.img"

if [ $(echo $rootdev | cut -b 6-9) = "loop" ]; then
    rootdev=$(ls -l $rootdev | sed 's/,//' | awk '{ printf("%02x%02x\n", $5, $6); }')
fi

cat > $cfgfile <<EOF
default linux
prompt 1
display boot.msg
timeout 100
label linux
        kernel vmlinuz
        append $INITRDARG $kernelargs root=$rootdev
EOF

[ $? = 0 ] || failed=1

[ -n "$verbose" ] && echo "append $INITRDARG kernelargs=$kernlargs root=$rootdev"


chmod 644 $cfgfile

if [ -f /etc/redhat-release ]; then
    title="$(sed 's/ release.*$//' < /etc/redhat-release)"
else
    title="Red Hat Linux"
fi


cat >> $bootmsg <<EOF

Press <return> (or wait 10 seconds) to boot your $title system from
$rootdev. You may override the default linux kernel parameters by typing
"linux <params>", followed by <return> if you like.

EOF

[ $? = 0 ] || failed=1

[ -n "$verbose" ] && echo "done."

mkisofs \
    -A "Red Hat Linux Boot CD" \
    -V "Red Hat Linux Boot CD" \
    -J -R -T -quiet \
    -o $device \
    -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot \
       -boot-load-size 4 -boot-info-table $MOUNTDIR
rm -rf $MOUNTDIR/*
rmdir $MOUNTDIR


if [ $failed -eq 1 ]; then
  exit 1
else
  exit 0
fi