#!/bin/bash

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

pause=yes
unset kernel
device=/dev/fd0
unset verbose
unset witheth
unset mkinitrdargs
unset compact

MOUNTDIR=/tmp/mkbootdisk
PATH=/sbin:$PATH
export PATH

VERSION=1.4.2

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

while [ $# -gt 0 ]; do
    case $1 in
	--device)
	    shift
	    device=$1
	    ;;
	--mkinitrdargs)
	    shift
	    mkinitrdargs=$1
	    ;;
	--help)
	    usage 0
	    ;;
	--noprompt)
	    unset pause
	    ;;
	-v)
	    verbose=true
	    ;;
	--verbose)
	    verbose=true
	    ;;
	--version)
	    echo "mkbootdisk: version $VERSION"
	    exit 0
	    ;;
	--compact)
	    compact="compact"
	    ;;
	*)
	    if [ -z "$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
}

[ -f /etc/modules.conf -a -f /lib/modules/$kernel/modules.dep ] && {
    ethmodule=`sort -u /etc/modules.conf | awk '/^alias eth0/ { print $3 }'`
    [ -n "$ethmodule" ] && {
	if echo $ethmodule | grep '\.o$'; then
	    ethmodule=`echo ${ethmodule} | sed "s/\.o$//"`
	fi
	deps=`grep "/net/$ethmodule.o" /lib/modules/$kernel/modules.dep | head -1`
	deps=`echo $deps | cut -d: -f2`
	for n in $deps; do
	    mod=`basename $n | cut -d. -f1`
	    witheth="$witheth --with $mod"
	done
	witheth="$witheth --with $ethmodule"
    }
}

[ -f /lib/modules/$kernel/fs/isofs.o ] &&
	withfs="$withfs --with isofs"
[ -f /lib/modules/$kernel/fs/nfs.o ] &&
	withfs="$withfs --with nfs"
[ -f /lib/modules/$kernel/fs/fat.o ] &&
	withfs="$withfs --with fat"
[ -f /lib/modules/$kernel/fs/msdos.o ] &&
	withfs="$withfs --with msdos"

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

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

[ -n "$pause" ] && {
    echo "Insert a disk in $device. Any information on the disk will be lost."
    echo -n "Press <Enter> to continue or ^C to abort: "
    read aline
}

[ -n "$verbose" ] && echo -n "Formatting $device... "
mkdosfs -I $device > /dev/null || {
    echo "Failed to format $device" >&2
    exit 1
}

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

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

mount -t vfat $device $MOUNTDIR || {
    rmdir $MOUNTDIR
    exit 1
}

[ -n "$verbose" ] && echo -n "Copying /boot/vmlinuz-$kernel... "
cp -a /boot/vmlinuz-$kernel $MOUNTDIR/vmlinuz
[ -n "$verbose" ] && echo "done."

[ -n "$verbose" ] && echo -n "Creating initrd image... "
/sbin/mkinitrd $mkinitrdargs $witheth --ifneeded $MOUNTDIR/initrd.img $kernel
[ -n "$verbose" ] && echo "done."

[ -n "$verbose" ] && echo -n "Setting up syslinux... "

[ -f $MOUNTDIR/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 > $MOUNTDIR/syslinux.cfg <<EOF
default linux
prompt 1
display boot.msg
timeout 100
label linux
	kernel vmlinuz
	append $INITRDARG root=$rootdev
EOF

chmod 644 $MOUNTDIR/syslinux.cfg

cat >> $MOUNTDIR/boot.msg <<EOF

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

EOF

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

umount $MOUNTDIR
rmdir $MOUNTDIR