#! /bin/sh
# ext-mount, a tool for mounting whichever drive (in a pool) is connected.
# Version 1.1
#
# Usage: ext-mount [ -vq ] [ -o <mount-options> ] [ <mount-point> ]
# Where:
#   -v  means verbose
#   -q  means don't print out the line from the pool file
#   -o  allows mount options to be given to mount (not arbitrary switches)
#
#   The mount point must not contain whitespace.  If not specified, the
#   file system must be listed by UUID in /etc/fstab.
#
# The pool is listed in /etc/ext-mount/media.conf in the following format,
# where the wildcard is the UUID of the desired file system on the disk:
#
#   xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx Optional arbitrary description
#
# Space or tab delimiters are supported.  Comments start with # at the
# beginning of the line.
#
#
# Copyright (C) 2011 Alastair Irvine <alastair@plug.org.au>
# Warpspace IT <http://www.warpspace.net/>
# 
#     This program is free software; you can redistribute it and/or modify
#     it under the terms of the GNU General Public License as published by
#     the Free Software Foundation; either version 2 of the License, or
#     (at your option) any later version.
# 
# On Debian systems, the complete text of the GNU General Public License
# can be found in `/usr/share/common-licenses/GPL'.
#
#
# TO-DO:
#   + attempt to unmount all pool drives beforehand (blame HAL)
#   + fail if a non most recently connected drive is mounted on <mount-point>
#   + mount the most recently connected drive


confdir=/etc/ext-mount
conf_hdds=$confdir/media.conf
cmd_verbose=false
cmd_quiet=false
self=`basename $0`
allowed_options=vqo:


log()
{
  if $cmd_verbose ; then
    echo "$@"
  fi
}

llog()
{
  if $cmd_verbose ; then
    echo -n "$@"
  fi
}


# *** MAINLINE ***
# == command-line handling ==
# process options
set -e
eval set -- `getopt --shell=sh -n $self +$allowed_options "$@"`
set +e        # getopt would have already reported the error

while [ x"$1" != x-- ] ; do
  case "$1" in
    -v) cmd_verbose=true ;;
    -q) cmd_quiet=true ;;
    -o) mount_opts="-o $2" ; shift ;;
  esac
  shift       # get rid of the option (or its arg if the inner shift already got rid it)
done
shift       # get rid of the "--"

# process remaining args
mount_point=$1


# == processing ==
# get the UUIDs from the first word of the non-comment lines in the pool file
uuids=`awk '/^[^#]/ { print $1; }' $conf_hdds`
# iterate through each UUID seeing if the partition is present
for uuid in $uuids ; do
  llog "Trying $uuid... "
  devpath=/dev/disk/by-uuid/$uuid
  if [ -e $devpath ] ; then
    found=$uuid
    found_devpath=$devpath
    llog "found: `file /dev/disk/by-uuid/$uuid`"
    if ! $cmd_quiet ; then
      # print the relevant line from the pool file
      grep $uuid $conf_hdds
    fi
  fi
  log  # print a newline (see llog at start of loop)
done

# if present, try to mount it
if [ $found ] ; then
  set -e
  # assumes that fs type detection works
  mount $mount_opts $found_devpath $mount_point
else
  echo no listed devices found >&2
  exit 2
fi