#!/usr/bin/bash

if [ $(/usr/bin/id -u) != 0 ]; then echo "only root can do that"; exit 2; fi

#***************************************************************************
# This file is part of the CRYPTO BONE
# File     : systemd.fetch 
# Version  : 2.0 (ALL-IN-ONE)
# License  : BSD-3-Clause
# Date     : 25 May 2025
# Contact  : Please send enquiries and bug-reports to innovation@senderek.ie
#
#
# Copyright (c) 2015-2025
#	Ralf Senderek, Ireland.  All rights reserved. (https://senderek.ie)
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer in the
#    documentation and/or other materials provided with the distribution.
# 3. All advertising materials mentioning features or use of this software
#    must display the following acknowledgement:
#	   This product includes software developed by Ralf Senderek.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND  ANY EXPRESS OR 
# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE  IMPLIED WARRANTIES 
# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  
# IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 
# PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 
# OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 
# WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
# POSSIBILITY OF SUCH DAMAGE.
#****************************************************************************

# no logs!

# This script is run periodically by systemd service cryptobone-fetch.service every 30 seconds.
# When the GUI is not active for 10 minutes, the service does not attempt to fetch a tarball
# from the server to avoid unnecessary network trafic.
# If the script safewebdrop/bin/requesttarball gets a tarball from the server comprising new
# encrypted webdrops and encrypted files, the tarball is first stored in ${RAM}/tarball.tgz
# Once such new tarball is present, an analysis is started that moves the tarball into the 
# TAR directory and runs safewebdrop/bin/analysetarball to extract the files being transferred
# from the server. It also starts the attempts to decrypt the received files with AES keys that
# are found in the database.


. /usr/lib/cryptobone/safewebdrop.header

GraceTime=600
FETCH=${RAM}/tarball.tgz

/usr/bin/mkdir ${RAM}/IN 2> /dev/null
/usr/bin/mkdir ${RAM}/FORENSIC 2> /dev/null
/usr/bin/mkdir ${RAM}/MESSAGES 2> /dev/null
/usr/bin/mkdir ${RAM}/FILES 2> /dev/null
/usr/bin/mkdir ${RAM}/TAR 2> /dev/null
/usr/bin/chmod 700 ${RAM}/MESSAGES ${RAM}/IN ${RAM}/FORENSIC ${RAM}/FILES 2> /dev/null

# only run systemd.fetch if GUI is active and $RAM/GUI exists
# every use of cbcontrol updates $RAM/GUI

if [ -s ${RAM}/GUI ]
then
     # check if GUI is still active
     NOW=$(date +%s)
     LAST=$(cat ${RAM}/GUI 2> /dev/null)
     delta=$(( $NOW - $LAST ))
     echo $delta > ${RAM}/delta
     if [ $delta -gt $GraceTime ]
     then
          date +%s > ${RAM}/exit
	  # grace time is over
	  /usr/bin/rm -f ${RAM}/GUI ${RAM}/delta
     fi
fi 

if [ -d ${RAM} ] && [ -s ${RAM}/GUI ]  ; then

     if [[ -r ${RAM}/TAR/tarball.tgz} ]]  ; then
           # analysis of recent ${FETCH} is still taking place, abort.
           exit 1
     fi
    

     /usr/bin/rm -f  $FETCH > /dev/null 2>&1
     ${CBHOME}/safewebdrop/bin/requesttarball

     if [[ -r $FETCH ]]; then
          /usr/bin/chmod 600 $FETCH 2> /dev/null
          /usr/bin/mv $FETCH ${RAM}/TAR 2> /dev/null

          ${CBHOME}/safewebdrop/bin/analysetarball 2> /dev/null
          FETCHFILE="${RAM}/tarball-$(/usr/bin/date +%y.%m.%d-%H.%M).tgz"

          /usr/bin/mv ${FETCH} ${FETCHFILE} 2> /dev/null
          /usr/bin/chmod 400 ${FETCHFILE} 2> /dev/null
	  # remove if size is 0
	  if [ ! -s ${FETCHFILE} ]
	  then
               /usr/bin/rm -f ${FETCHFILE}  
	  fi
     fi
fi
exit 0