#!/bin/sh

# Creates a bootable (LILO) floppy for embedded Linux usage.

# This script has to be run as root, and has therefore been
# kept short and legible, so security conscious people can
# read it and confirm that it only does what it should.

# Larry Doolittle   <LRDoolittle@lbl.gov>  September 2000

# What you need before running this script (as root):
#    KERNEL  pointed to actual kernel
#    IMAGE   pointed to actual compressed filesystem image
# both of these will be installed on the floppy.
# See make_image for help on the latter.  I trust you know
# how to make a kernel, otherwise see /usr/src/linux/README.

# If you want to run this process without a real floppy
# in hand (and dd the result to a floppy later), set
# DEV=/dev/loop0, where /dev/loop0 has been losetup to
# a regular 1.44 Meg file.  See "man losetup".
DEV=/dev/fd0                # target device
FSYS=/mnt/floppy            # device is mounted here during installation
KERNEL=./bzImage            # suggest bz2 compression
IMAGE=./image.gz            # Compressed ramdisk image
MESSAGE=./message           # Displayed at boot time
BOOTBLK=/boot/boot.b        # LILO bootblock stolen from your running system

PATH=/sbin:${PATH}

test -r $KERNEL  || exit
test -r $IMAGE   || exit
test -r $BOOTBLK || exit

echo; echo "Setting up bootable filesystem on $DEV"
mke2fs -m 0 $DEV  || exit
mount $DEV $FSYS  || exit
echo; echo "Blank filesystem now mounted on $FSYS"

umask 022
# otherwise LILO complains that /etc/lilo.conf should be writable only for root

mkdir $FSYS/{etc,boot,dev}
cat <<EOF >$FSYS/etc/lilo.conf
boot=/dev/fd0
map=/boot/map
install=/boot/boot.b
message=/boot/message
compact
# linear
prompt
timeout=5
image=/boot/vmlinuz
    label=linux
    root=/dev/ram0
    initrd=/boot/ramdisk_image.gz
    read-only
EOF
# Note the consistency of the following literal target filenames
# with the above literal lilo.conf.
cp $KERNEL  $FSYS/boot/vmlinuz
cp $IMAGE   $FSYS/boot/ramdisk_image.gz
cp $BOOTBLK $FSYS/boot/boot.b
if [ -r $MESSAGE ]; then
    cp $MESSAGE $FSYS/boot/message
else
    cat <<EOF > $FSYS/boot/message

Single floppy boot setup courtesy Larry Doolittle <LRDoolittle@lbl.gov>

EOF
fi

# Have to set up enough devices on the floppy that
# the chroot'ed LILO knows what it's doing.
( cd $FSYS/dev
  mknod -m 660 fd0 b 2  0; chown root:floppy fd0
  mknod -m 660 hda b 3  0; chown root:disk   hda
  mknod -m 660 hdb b 3 64; chown root:disk   hda
  for part in 1 2 3 4 5 6 7 8; do
  mknod -m 660 hda$part b 3 $part;         chown root:disk hda$part
  mknod -m 660 hdb$part b 3 $((64+$part)); chown root:disk hdb$part
  done
  for ix in 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15; do
  mknod -m 660 ram$ix b 1 $ix; chown root:disk ram$ix
  done
)

# ... and the rubber meets the road.
echo "Everything (virtually) done except LILO"
lilo -v -r $FSYS
echo "Unmounting $FSYS"
umount $FSYS
echo "Done!  $DEV should now be bootable."