#!/bin/bash
 set -e -E -u
 #
 # given a remote user@host with ssh-personal-environment installed, determine the maximum amount of random
 # data that can be transferred via the environment variables.

 TARGET="$1" ; shift

 data_file=$(mktemp)
 data_filename=${data_file##*/}
 data_dirname=${data_file%/*}
 trap "rm -f $data_file" 0

 unset SSH_PERS_ENV_DEBUG

 lastsize=0
 for size in $(eval echo {${MIN:=10}..${MAX:=150}..${STEP:=10}}) ; do
         dd if=/dev/urandom bs=1k count="$size" of="$data_file" status=none
         checksum=( $(md5sum "$data_file") )

         echo "TESTING $size KB"
         remote_checksum=( $(
                 export SSH_PERS_ENV_DATA=$(tar -C "$data_dirname" -cz "$data_filename" | base64)
                 ssh "$TARGET" md5sum "$data_filename" \; rm -f "$data_filename" 2>/dev/null || echo FAILED
                 ) )
         if [[ $checksum != $remote_checksum ]] ; then
                 echo "FAILED to transfer $size KB, safe size is $lastsize KB"
                 exit 0
         fi
         let lastsize=size
 done