sdbackup

#!/bin/bash
#--------------------------------------------------------------------------------
#  SDBackup
#  A script to backup a device such as an SD Card to a compressed image
#--------------------------------------------------------------------------------
#  Daniel Bull
#  daniel@neonhorizon.co.uk
#------------------------------------------------------------------------------*/


# Settings
thisapp="$(basename "$0")"
settingsfile=~/.sdbackup
defaultdev=""

# Automatically install what we need
if [[ ! $(type -P "unp") || ! $(type -P "ddrescue") || ! $(type -P "lshw") ]]; then
  echo "It looks like this is the first time $thisapp has been run."
  echo "Installing required packages..."
  echo
  sudo apt-get install unp gddrescue lshw || { echo "Error: Please install unp, gddrescue and lshw" 1>&2; exit 1;}
  echo "Done..."
  echo
fi

# Create the temporary folder if it doesn't already exist
if ! tempfolder="$(mktemp -td sdbackup.tmp.XXXXXXXX)"; then
  echo "Error: Cannot create temporary folder" 1>&2
  exit 1
fi

# Check filename parameter is present
if [[ "$1" = "" ]]; then
  echo "Usage: $thisapp <filename> [<device>]" 1>&2
  exit
fi

# Automatically add .gz extension if its not there
file="$1"
if ! [[ "$file" == *".gz" ]]; then
  file+=".gz"
fi

# Check target file doesnt already exist
if [[ -d "$file" ]]; then
  echo "Error: $file is a directory?" 1>&2
  exit 1
elif [[ -f "$file" ]]; then
  # Confirm overwite
  read -rp "$file already exists, should it be deleted? [y/N]: " -n1 agree
  if ! [[ "$agree" =~ ^[yY]$ ]]; then
    exit
  fi
  echo
  rm "$file" || { echo "Error: Cannot delete $file" 1>&2; exit 1; }
  echo "Deleted $file"
  echo
fi

# Get a device name
if [[ "$2" != "" ]]; then
  # Supplied on CLI
  dev="$2"
else

  # Get the default
  if [[ -f "$settingsfile" ]]; then
    defaultdev="$(cat "$settingsfile")"
  fi

  # Scan for disks
  echo "Scanning drives..."
  declare -a line
  declare -a devices
  declare -a sizes
  declare -a names
  device=0;
  while IFS=":" read -r -a line; do
  case "${line[0]}" in
    *"description")
      device=$((device+1))
      devices[$device]=""
      sizes[$device]=""
      names[$device]=""
      ;;
    *"logical name")
      devices[$device]="${line[1]# }"
      ;;
    *"size")
      sizes[$device]+="${line[1]# }"
      ;;
    *"product")
      names[$device]+="${line[1]# }"
      ;;
  esac
  done < <(sudo lshw -class disk 2> /dev/null)
  unset line

  # Display a list of options
  echo
  defaultselect=0
  for i in "${!devices[@]}"; do
    if [[ "${sizes[$i]}" ]]; then
      echo "$i) ${devices[$i]} ${names[$i]} (${sizes[$i]})"
    else
      echo "$i) ${devices[$i]} ${names[$i]} (currently empty)"
    fi
    if [[ "${devices[$i]:1}" = "$defaultdev" ]]; then
      defaultselect=$i
    fi
  done
  echo "0)  Cancel"

  # Ask the user to select
  echo
  dev=""
  while ! [[ "$dev" ]]; do
    read -rp "Please select your device [$defaultselect]: " selected
    if ! [[ "$selected" ]]; then
      selected=$defaultselect
    fi
    if [[ "$selected" = 0 ]]; then
      exit;
    fi
    if [[ "$selected" =~ ^[01234567890]$ ]]; then
      dev="${devices["$selected"]:1}"
    fi
  done

fi

# Check the device exists
if [[ ! -b "$dev" ]]; then
  echo "Error: $dev is not a block device?" 1>&2
  exit 1;
fi

# Confirm
read -rp "Backup from $dev to $file is that correct? [y/N]: " -n1 agree
if ! [[ "$agree" =~ ^[yY]$ ]]; then
  exit
fi
echo
echo

# Filenames
lockfile="/tmp/sdbackup${dev////_}.lock"
tempfile="$tempfolder/${file}_${dev////_}.tempfile"

# Test and create lockfile
if [[ -f $lockfile ]]; then
  echo "Error: There is a $(cat "$lockfile") currently running on $dev" 1>&2;
  exit 1;
fi
echo "$thisapp ($$)" > "$lockfile"

# Trap for failure
trap 'rm "$lockfile" 2> /dev/null; rm "$tempfile" 2> /dev/null; rmdir "$tempfolder" 2> /dev/null' EXIT

# Clean up anything left over from a previous attempt
sudo rm "/tmp/sdbackup.tmp."*/*.tempfile 2> /dev/null
sudo rmdir "/tmp/sdbackup.tmp."* 2> /dev/null

# Unmount the card
echo "Unmounting any mounted partitions..."
for partition in "$dev"*; do
  if [[ -b "$partition" ]]; then
    if grep -Eqs ^"$partition " /proc/mounts; then
      sudo umount "$partition" 2> /dev/null || { echo "Error: Cannot unmount $partition" 1>&2; exit 1; }
    fi
  fi
done

# Create a temp file with our user (so we don't need sudo to delete it)
touch "$tempfile"

# Back it up
echo "Copying data from $dev..."
echo
sudo ddrescue "$dev" "$tempfile" || exit 1;
echo
echo "Zipping..."
gzip --stdout "$tempfile" > "$file" || { echo "Error: Cannot compress the file" 1>&2; exit 1; }
echo "Backup complete."

# Set device as default
echo "$dev" > "$settingsfile"