mount-img-parts

#!/bin/sh
#
# Script to easily access/mount and manipulate with partitions of image file
#
# Copyright (C) 2014 Pavel Pisa <ppisa@pikron.com>

# 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 3 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, see <http://www.gnu.org/licenses/>.

my_dir="$(pwd)"
lopart_dir="$my_dir/lopart"
imgmnt_dir="$my_dir/imgmnt"
img_file=$my_dir/rpi-wheezy-overlay

if [ $# -lt 1 ] ; then
  echo "usage: mount-img-parts [mount|umount|losetup|lodetach] [img_file]"
  exit 1
fi

action=$1

if [ $# -ge 2 ] ; then
  img_file="$(readlink -f "$2")"
fi

case $action in
  losetup)
    for loop_dev in $(find $lopart_dir -name "pdev*" ) ; do
      /sbin/losetup -d $loop_dev 2>/dev/null
    done
    for loop_dev in $(losetup -a | sed -n -e 's#^\([^ ]*\): [^(]*('"$img_file"').*$#\1#p') ; do
      /sbin/losetup -d $loop_dev 2>/dev/null
    done
    rm -f "$lopart_dir/pdev"*

    echo "setting loops for /home/pi/projects/rpi/archive/lopart/loop0"
    loop_dev="$(losetup -f --show $img_file)"
    if [ $? -ne 0 ] ; then
      echo >2 "failed: losetup -f --show $img_file"
      exit 1
    fi
    cp -a "$loop_dev" "$lopart_dir/pdev0"
    ;;
  lodetach)
    for mntpt_dir in $(sed -n -e 's#/dev/loop[0-9]* \('"$imgmnt_dir/[^ ]*"'\) .*$#\1#p' /proc/mounts) ; do
      echo "unmounting $mntpt_dir"
      umount "$mntpt_dir"
      rmdir "$mntpt_dir"
    done
    for loop_dev in $(find $lopart_dir -name "pdev*" ) ; do
      /sbin/losetup -d $loop_dev 2>/dev/null
    done
    for loop_dev in $(losetup -a | sed -n -e 's#^\([^ ]*\): [^(]*('"$img_file"').*$#\1#p') ; do
      echo "losetup detach $loop_dev"
      /sbin/losetup -d $loop_dev
    done
    rm -f "$lopart_dir/pdev"*
    exit 0
    ;;
esac

/sbin/parted $img_file -ms unit B p | tr ':B' ' ' | (
  while read pnum pstart pend psize ptype ; do
    case $pnum in
      [1-4])
        echo "$action pnum=$pnum pstart=$pstart pend=$pend psize=$psize ptype=$ptype"
        case $action in
          mount)
            mkdir -p "$imgmnt_dir/p$pnum" || exit 1
            mount -o loop,offset=$pstart,sizelimit=$psize "$img_file" "$imgmnt_dir/p$pnum" || exit 1
            ;;
          umount)
            umount "$imgmnt_dir/p$pnum"
            rmdir "$imgmnt_dir/p$pnum"
            ;;
          losetup)
            mkdir -p "$lopart_dir" || exit 1
            loop_dev="$(losetup --offset $pstart --sizelimit $psize -f --show $img_file)"
            if [ $? -ne 0 ] ; then
              echo >2 "failed: losetup --offset $pstart --sizelimit $psize -f --show $img_file"
              exit 1
            fi
            rm -f "$lopart_dir/pdev0p$pnum"
            cp -a "$loop_dev" "$lopart_dir/pdev0p$pnum"
        esac
        ;;
    esac
  done
)