#! /bin/bash

#*********************************************************************
#
# This script is part of FAI (Fully Automatic Installation)
# (c) 2003-2006 by Thomas Lange, lange@informatik.uni-koeln.de
# Universitaet zu Koeln
#
#*********************************************************************

# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
mkrwsize() {

    # save all dirs and files under directory $2
    # mount tmpfs on top of dir $2
    # extract dirs and files into tmpfs

    local n=

    if [ ! -d "$2" ]; then
	echo "WARNING: $2 is not a directory. Cannot make it writeable."
	return
    fi

    # test for already writable
    temp=$(mktemp -q -p $2)
    if [ $? -eq 0 ]; then
	echo "mkrw: $2 is already writable."
	rm $temp
	return
    fi

    [ -n "$3" ] && n="-n"

    local tmp1=$(mktemp) || exit 12
    tar -C $2 -cf $tmp1 .
    mount $n -o size=$1 -t tmpfs tmpfs $2
    tar -C $2 -xf $tmp1
    rm -f $tmp1
}
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

size=10m # default size

while getopts s:n opt ; do
    case "$opt" in
        s) size="$OPTARG" ;;
        n) no_mount=1 ;;
        esac
done
shift $(($OPTIND - 1))

for d in "$@"; do
    [ -d "$d" ] && mkrwsize $size $d $no_mount
done
