#!/bin/sh
#
# This script generates a "memstick image" (image that can be copied to a
# USB memory stick) from a directory tree.  Note that the script does not
# clean up after itself very well for error conditions on purpose so the
# problem can be diagnosed (full filesystem most likely but ...).
#
# Usage: make-memstick.sh <directory tree> <image filename>
#
# $FreeBSD$
#

PATH=/bin:/usr/bin:/sbin:/usr/sbin
export PATH

BLOCKSIZE=10240

if [ $# -ne 2 ]; then
  echo "make-memstick.sh /path/to/directory /path/to/image/file"
  exit 1
fi

tempfile="${2}.$$"

if [ ! -d ${1} ]; then
  echo "${1} must be a directory"
  exit 1
fi

if [ -e ${2} ]; then
  echo "won't overwrite ${2}"
  exit 1
fi

echo '/dev/da0s3 / ufs ro,noatime 1 1' > ${1}/etc/fstab
rm -f ${tempfile}
makefs -B big ${tempfile} ${1}
if [ $? -ne 0 ]; then
  echo "makefs failed"
  exit 1
fi
rm ${1}/etc/fstab

#
# Use $BLOCKSIZE for transfers to improve efficiency.  When calculating
# how many blocks to transfer "+ 2" is to account for truncation in the
# division and to provide space for the label.
#

filesize=`stat -f "%z" ${tempfile}`
blocks=$(($filesize / ${BLOCKSIZE} + 1728))
dd if=/dev/zero of=${2} bs=${BLOCKSIZE} count=${blocks}
if [ $? -ne 0 ]; then
  echo "creation of image file failed"
  exit 1
fi

unit=`mdconfig -a -t vnode -f ${2}`
if [ $? -ne 0 ]; then
  echo "mdconfig failed"
  exit 1
fi

gpart create -s APM ${unit}
gpart add -t freebsd-boot -s 800K ${unit}
gpart bootcode -p ${1}/boot/boot1.hfs -i 1 ${unit}
gpart add -t freebsd-ufs -l FreeBSD_Install ${unit}

dd if=${tempfile} of=/dev/${unit}s3 bs=$BLOCKSIZE conv=sync
if [ $? -ne 0 ]; then
  echo "copying filesystem into image file failed"
  exit 1
fi

mdconfig -d -u ${unit}

rm -f ${tempfile}