#!/bin/sh
###############################################################################
## (c) 2003 Samuel Abels
## This script will backup a list of all files to a tape device.
## The tape will be deleted before.
##
## Requires:   mt, mt-dds (=dds2tar), tar.
##
## Changelog:  2003-04-05 S. Abels
##               Initial.
##             2003-04-06 S. Abels
##               Error detection fix.
##               Faster backup list creation.
##               Multiple files fix.
##             2003-04-06 S. Abels
##               Optional tape deletion.
##             2003-04-07 S. Abels
##               File size calculation fix.
##               Added an extra verbosity level.
##             2003-11-08 S. Abels
##               Date evaluation fix.
##               Some small cleanups.
###############################################################################
##

TIMESTAMP='date +%s%N'  # Change this if you don't use GNU-date.
DATE='date "+%F %R"'    # Change this if you don't use GNU-date.
ITEMPFILE="/tmp/includelist`eval "$TIMESTAMP"`"
XTEMPFILE="/tmp/excludelist`eval "$TIMESTAMP"`"


###############################################################################
# Function to display the correct usage if the user tries to use an
# unsupported option.
###############################################################################

printUsage()
{
  echo "Syntax: $0 [-y] [-e excludes] files" 1>&2
  echo >&2
  echo -e "\tfiles\t\tA list of files/directories to backup." >&2
  echo -e "\t-d device\tYour backup device. Default is /dev/nst0." >&2
  echo -e "\t-l kilobytes\tTape length in kilobytes. Default is 4 000 000 (4 GB)." >&2
  echo -e "\t-e excludes\tFiles/directories to exclude from the backup." >&2
  echo -e "\t-D\t\tDelete the tape before writing." >&2
  echo -e "\t-y\t\tAssume YES to all questions." >&2
  echo -e "\t-v\t\tVerbose mode." >&2
  echo -e "\t-V\t\tMore verbose mode." >&2
  echo -e "\t-vv\t\tExcessive verbose mode." >&2
}


###############################################################################
# Use getopt to determine the allowed options.
###############################################################################

getopt "d:l:e:DVyvv" $* 1>/dev/null 2>&1
if [ $? != 0 ]; then
  printUsage
  exit 1
fi


###############################################################################
# This for-loop parses the command line for options and sets a variable
# accordingly.
###############################################################################

# Default options.
DELTAPE=0
CONFIRMED=0
VERBOSE=0
DEVICE="/dev/nst0"
TAPELEN=4000000

for i in "$@"; do
  case $i in
    "-e")
      EXCLUDEFILES="$2"
      shift 2;;
    "-d")
      DEVICE="$2"
      shift 2;;
    "-l")
      TAPELEN="$2"
      shift 2;;
    "-D")
      DELTAPE=1
      shift;;
    "-y")
      CONFIRMED=1
      shift;;
    "-v")
      VERBOSE=1
      shift;;
    "-V")
      VERBOSE=2
      shift;;
    "-vv")
      VERBOSE=3
      shift;;
    # End of options, just command arguments left.
    "--")
      shift
      break;;
  esac
done

FILES=$*


###############################################################################
# Let the user know what will be done.
###############################################################################

# Verbosity level
[ $VERBOSE -eq 1 ] && echo "Using verbose mode."
[ $VERBOSE -eq 2 ] && echo "Using more verbose mode."
[ $VERBOSE -eq 3 ] && echo "Using excessive verbose mode."

# List files.
echo "Backing up:"
echo "$FILES" | sed 's/ /\\  /g' | sed 's/\\ /\n/g' | while read CURFILE; do
  echo " $CURFILE"
done
echo

echo "Excluding: "
echo "$EXCLUDEFILES" | sed 's/ /\\  /g' | sed 's/\\ /\n/g' | while read CURFILE; do
  echo " $CURFILE"
done
echo

echo -n "Backup device is $DEVICE."

[ $DELTAPE -ne 1 ] && echo -ne "\nThe tape will be erased before writing."

if [ $CONFIRMED -ne 1 ]; then
  echo -n " Continue (y/N)? "
  read -n1 CONFIRMATION
  
  if [ "$CONFIRMATION" != "y" ]; then
    echo -e "\nAborted." >&2
    exit 0
  fi
fi
echo


###############################################################################
# Create a full list of files to backup.
###############################################################################

echo -n "`eval "$DATE"`: Writing backuplist to $ITEMPFILE... "

# 1. Create a list of files to include.
# 2. Append a list of excludefiles to THE SAME FILE.
# 3. Remove double lines completely. That means, the excludes are gone.
if [ $VERBOSE -eq 0 ]; then
  du -ab $FILES | cut -f2- > "$XTEMPFILE" 2>/dev/null \
  && du -ab $EXCLUDEFILES | cut -f2- >> "$XTEMPFILE" 2>/dev/null \
  && cat "$XTEMPFILE" | sort | uniq -u > "$ITEMPFILE" 2>/dev/null
  ERR=$?
fi

if [ $VERBOSE -eq 1 -o $VERBOSE -eq 2 ]; then
  du -ab $FILES | cut -f2- > "$XTEMPFILE" \
  && du -ab $EXCLUDEFILES | cut -f2- >> "$XTEMPFILE" \
  && cat "$XTEMPFILE" | sort | uniq -u > "$ITEMPFILE"
  ERR=$?
fi

if [ $VERBOSE -eq 3 ]; then
  echo
  du -ab $FILES | cut -f2- > "$XTEMPFILE" \
  && du -ab $EXCLUDEFILES | cut -f2- >> "$XTEMPFILE" \
  && cat "$XTEMPFILE" | sort | uniq -u | tee "$ITEMPFILE"
  ERR=$?
fi

rm "$XTEMPFILE" >/dev/null 2>&1

# Fetch errors.
[ $ERR -ne 0 ] && echo -e "Failed!\nError: Failed to create backuplist '$ITEMPFILE'." >&2 && exit 1

echo "done."

# Warning on empty files.
[ ! -s "$ITEMPFILE" ] && echo "Warning: Backuplist is empty. '$ITEMPFILE'" >&2

# Count filesizes.
SUM=0
echo -n "`eval "$DATE"`: Precalculating sizes... "
for SIZE in `cat "$ITEMPFILE" | while read FILE; do echo \`ls -la "$FILE" | awk '{print $5}'\`; done`; do
  SUM=`expr $SUM + $SIZE`
done
echo "done."

# Let the user decide if this is ok.
SUM=`expr $SUM / 1024`
echo -n "Size is $SUM kilobytes."
if [ $CONFIRMED -ne 1 ]; then
  echo -n " Continue (y/N)? "
  read -n1 CONFIRMATION
  
  if [ "$CONFIRMATION" != "y" ]; then
    echo -e "\nAborted." >&2
    exit 0
  fi
fi
echo


###############################################################################
# Rewind the tape using mt.
###############################################################################

echo -n "`eval "$DATE"`: Rewinding tape... "
if [ $VERBOSE -eq 0 ]; then
  mt -f "$DEVICE" rewind >/dev/null 2>&1
  ERR=$?
fi
if [ $VERBOSE -eq 1 ]; then
  mt -f "$DEVICE" rewind >/dev/null
  ERR=$?
fi
if [ $VERBOSE -eq 2 -o $VERBOSE -eq 3 ]; then
  mt -f "$DEVICE" rewind
  ERR=$?
fi

# Fetch errors.
[ $ERR -ne 0 ] && echo -e "Failed!\n`eval "$DATE"`: Error: Failed to rewind the tape." >&2 && exit 1

echo "done."


###############################################################################
# Delete the tape using mt.
###############################################################################

if [ $DELTAPE -eq 1 ]; then
  # Deletion starts here.
  echo -n "`eval "$DATE"`: Erasing tape... "
  if [ $VERBOSE -eq 0 ]; then
    mt -f "$DEVICE" erase >/dev/null 2>&1
    ERR=$?
  fi
  if [ $VERBOSE -eq 1 ]; then
    mt -f "$DEVICE" erase >/dev/null
    ERR=$?
  fi
  if [ $VERBOSE -eq 2 -o $VERBOSE -eq 3 ]; then
    mt -f "$DEVICE" erase
    ERR=$?
  fi
  
  # Fetch errors.
  [ $ERR -ne 0 ] && echo -e "Failed!\n`eval "$DATE"`: Error: Failed to erase the tape." >&2 && exit 1
  
  echo "done."
  
  # Re-rewind the tape
  echo -n "`eval "$DATE"`: Rewinding tape... "
  if [ $VERBOSE -eq 0 ]; then
    mt -f "$DEVICE" rewind >/dev/null 2>&1
    ERR=$?
  fi
  if [ $VERBOSE -eq 1 ]; then
    mt -f "$DEVICE" rewind >/dev/null
    ERR=$?
  fi
  if [ $VERBOSE -eq 2 -o $VERBOSE -eq 3 ]; then
    mt -f "$DEVICE" rewind
    ERR=$?
  fi
  
  # Fetch errors.
  [ $ERR -ne 0 ] && echo -e "Failed!\n`eval "$DATE"`: Error: Failed to rewind the tape." >&2 && exit 1
  
  echo "done."
fi


###############################################################################
# Enable the tape's hardware compression.
###############################################################################

echo -n "`eval "$DATE"`: Enabling tape hardware compression... "
if [ $VERBOSE -eq 0 ]; then
  mt-dds -f "$DEVICE" comp-on >/dev/null 2>&1
  ERR=$?
fi
if [ $VERBOSE -eq 1 ]; then
  mt-dds -f "$DEVICE" comp-on >/dev/null
  ERR=$?
fi
if [ $VERBOSE -eq 2 -o $VERBOSE -eq 3 ]; then
  mt-dds -f "$DEVICE" comp-on
  ERR=$?
fi

# Fetch errors.
[ $ERR -ne 0 ] && echo -e "Failed!\n`eval "$DATE"`: Error: Enabling tape hardware compression didn't work." >&2 && exit 1

echo "done."


###############################################################################
# Write the backup to the device.
###############################################################################

echo "`eval "$DATE"`: Writing files from $ITEMPFILE to $DEVICE..."
if [ $VERBOSE -eq 0 ]; then
  tar --tape-length $TAPELEN --no-recursion --totals -vcf "$DEVICE" -T "$ITEMPFILE" >/dev/null 2>&1
  ERR=$?
fi
if [ $VERBOSE -eq 1 ]; then
  tar --tape-length $TAPELEN --no-recursion --totals -vcf "$DEVICE" -T "$ITEMPFILE" >/dev/null
  ERR=$?
fi
if [ $VERBOSE -eq 2 -o $VERBOSE -eq 3 ]; then
  tar --tape-length $TAPELEN --no-recursion --totals -vcf "$DEVICE" -T "$ITEMPFILE"
  ERR=$?
fi

# Fetch errors.
[ $ERR -ne 0 ] && echo "`eval "$DATE"`: Error: Writing the backup failed!" >&2 && exit 1

echo "`eval "$DATE"`: Backup finished successfully!"


###############################################################################
# Delete the tempfile.
###############################################################################

echo -n "`eval "$DATE"`: Deleting tempfile... "
rm "$ITEMPFILE" >/dev/null 2>&1
if [ $? -ne 0 ]; then
  echo "Failed!"
  exit 1
fi
echo "done."