# Helper library for update-grub
# Copyright (C) 2007 Free Software Foundation, Inc.
#
# This file 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.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St - Suite 330, Boston, MA 02110, USA.

transform="@program_transform_name@"

prefix=@prefix@
exec_prefix=@exec_prefix@
sbindir=@sbindir@

grub_probe=${sbindir}/`echo grub-probe | sed ${transform}`

make_system_path_relative_to_its_root ()
{
  path=$1
  # abort if file doesn't exist
  if test -e $path ; then : ;else
    return 1
  fi

  # canonicalize
  if path=`readlink -f $path` ; then : ; else
    return 1
  fi

  # if not a directory, climb up to the directory containing it
  if test -d $path ; then
    dir=$path
  else
    dir=`echo $path | sed -e "s,/[^/]*$,,g"`
  fi

  num=`stat -c %d $dir`

  # this loop sets $dir to the root directory of the filesystem we're inspecting
  while : ; do
    parent=`readlink -f $dir/..`
    if [ "x`stat -c %d $parent`" = "x$num" ] ; then : ; else
      # $parent is another filesystem; we found it.
      break
    fi
    if [ "x$dir" = "x/" ] ; then
      # / is our root.
      break
    fi
    dir=$parent
  done

  echo $path | sed -e "s,^$dir,/,g" -e "s,//,/,g"
}

convert_system_path_to_grub_path ()
{
  path=$1

  # abort if file doesn't exist
  if test -e $path ; then : ;else
    return 1
  fi

  # abort if file is in a filesystem we can't read
  if ${grub_probe} -t fs $path > /dev/null 2>&1 ; then : ; else
    return 1
  fi

  if drive=`${grub_probe} -t drive $path` ; then : ; else
    return 1
  fi

  if relative_path=`make_system_path_relative_to_its_root $path` ; then : ; else
    return 1
  fi

  # remove any trailing slash, even if that slash is everything we have
  relative_path=`echo ${relative_path} | sed -e "s,/*$,,g"`

  echo ${drive}${relative_path}
}