#!/bin/sh
# makerd --- creates an initrd ramdisk file from an existing directory tree.
# Copyright © 2001 Jamie Zawinski <jwz@dnalounge.com>
#
# Permission to use, copy, modify, distribute, and sell this software and its
# documentation for any purpose is hereby granted without fee, provided that
# the above copyright notice appear in all copies and that both that
# copyright notice and this permission notice appear in supporting
# documentation.  No representations are made about the suitability of this
# software for any purpose.  It is provided "as is" without express or 
# implied warranty.
#
# Created by jwz, 23-Dec-2000

verbose=
dir=
target=

# Increase this if you get "No space left on device" errors.
IMAGESIZE=700

make_ramdisk() {

  IMAGE=$target.tmp
  dd if=/dev/zero of=$IMAGE bs=1k count=$IMAGESIZE 2> /dev/null

  for devnum in 0 1 2 3 4 5 6 7 8; do
    if losetup /dev/loop$devnum $IMAGE 2>/dev/null ; then break; fi
  done

  if [ "$devnum" = "8" ]; then
    rm -rf $IMAGE
    echo "All of your loopback devices are in use!" >&2
    exit 1
  fi

  LODEV=/dev/loop$devnum

  if [ -n "$verbose" ]; then
    echo "Using loopback device $LODEV"
  fi

  echo y | mke2fs $LODEV $IMAGESIZE >/dev/null 2>/dev/null

  MNTPOINT=$target.mnt
  rm -rf $MNTPOINT
  mkdir $MNTPOINT

  mount -t ext2 $LODEV $MNTPOINT || {
    echo "Can't get a loopback device"
    exit 1
  }

  rmdir $MNTPOINT/lost+found

  cpio_v=""
  if [ -n "$verbose" ]; then
    echo "Copying $dir..."
    dash_v="-v"
  fi

  cwd=`pwd`
  ( cd $dir; find . -depth -print | 
    cpio $dash_v --quiet -pdm $cwd/$MNTPOINT ) \
    2>&1 | sed "s@$cwd/$MNTPOINT/\./@/@g" | sed 's@^@    @'

  umount $MNTPOINT
  losetup -d $LODEV

  ( gzip $dash_v -9 < $IMAGE > $target ) 2>&1 | sed 's@^@Compression:@'
  rmdir $MNTPOINT
  rm -rf $IMAGE

  if [ -n "$verbose" ]; then
    echo "Wrote $target:"
    ls -ldGF $target
  fi
}


usage() {
  echo "usage: `basename $0` [-v] input-directory output-ramdisk-file"
  exit 1
}

main() {
  while [ $# -gt 0 ]; do
    case $1 in
     -v)
       verbose=1
       ;;
     *)
       if [ -z "$dir" ]; then
         dir=$1
       elif [ -z "$target" ]; then
         target=$1
       else
         usage
       fi
       ;;
    esac
    shift
  done

  if [ -z "$dir" -o -z "$target" ]; then
    usage
  fi

  make_ramdisk
}

main "$@"
exit 0