bitcoin-new-onion-address.sh

#!/bin/bash
#
# Description:
# This script is used to set (fresh) values in bitcoin.conf file
#
# TODO:
# - Integrate while loop to check if /tmp/hidden_service/hostname exists with 'sed'ting the new hostname in the bitcoin.conf file
# - A presumably 'stale' lockfile/LOCKDIR is removed after 2 hours. Look into a more elegant solution.
#

# Bash options
set -o errexit # exit script when a command fails
set -o nounset # exit script when a variable is not set


# Variables
export RANDFILE=/etc/onion-node/.rnd

readonly ONION_DIR=/etc/onion-node
readonly BITCOIN_USER=bitcoinuser
readonly BITCOIN_FILE=/home/"${BITCOIN_USER}"/.bitcoin/bitcoin.conf # Location of bitcoin configuration file
readonly OPENSSL_KEY="$(openssl rand -base64 48)" # Generate pseudo-random base64 string
readonly NEW_RPC_PASSWORD="$(echo -n "${OPENSSL_KEY}" | sha256sum | head -c 64)" # Convert base64 string to alphanumeric characters
readonly OLD_RPC_PASSWORD=CHANGETHISPASSWORD # bitcoin.conf default rpc password
readonly EXTERNAL_IP=externalip=
readonly LOCK_DIR=/tmp/tor-bitcoin.lock/


# Only run as root
if [[ "$(id -u)" != "0" ]]; then
  echo "ERROR: Must be run as root...exiting script"
  exit 0
fi

# Check if a lockfile/LOCKDIR exists, wait max 2 hours to remove 'stale' lockfile and exit script
tries=0
while [[ -d "${LOCK_DIR}" ]] && [[ "${tries}" -lt 120 ]]; do
  echo "Temporarily not able to acquire lock on ${LOCK_DIR}"
  echo "Other processes might be running...retry in 60 seconds"
  sleep 60
  tries=$(( ${tries} +1 ))
  if [[ $tries -eq 120 ]]; then
    echo "ERROR: After 2 hours the ${LOCK_DIR} still exists"
    echo "Not a good sign"
    echo "Removing presumably stale ${LOCK_DIR}"
    rmdir "${LOCK_DIR}"
  fi
done

# Set lockfile/dir - mkdir is atomic
# For portability flock or other Linux only tools are not used
if mkdir "${LOCK_DIR}"; then
  trap 'rmdir "${LOCK_DIR}"; exit' INT TERM EXIT # remove LOCKDIR when script is interrupted, terminated or finished
  echo "Successfully acquired lock on ${LOCK_DIR}"
else
  echo "Failed to acquire lock on ${LOCK_DIR}"
  exit 0
fi

# Stop bitcoin process - execute bitcoin-control.sh script
echo "Stopping bitcoin process"
"${ONION_DIR}"/bitcoin-control.sh
echo "Bitcoin process has quit"

# Change .onion address
echo "Stopping tor to create new .onion address"
/etc/init.d/tor stop
echo "Sleeping for 30 seconds to let the Tor process stop smoothly"
sleep 30
rm -rf /tmp/hidden_service
sleep 5
echo "Starting tor for new .onion address"
/etc/init.d/tor start
echo "Sleeping for 30 seconds to let the Tor process start smoothly"
sleep 30

# Check if Tor hostname file exists, if not sleep for a while
tries=0
while [[ ! -r /tmp/hidden_service/hostname ]] && [[ "${tries}" -lt 10 ]]; do
  echo "Tor hostname not available...waiting for 30 seconds"
  sleep 30
  tries=$(( ${tries} +1 ))
  if [[ $tries -eq 5 ]]; then
    echo "Tor hidden service not created yet...restarting Tor"
    /etc/init.d/tor restart
    sleep 30
  fi
  if [[ $tries -eq 10 ]]; then
    echo "Tor hidden service not created properly...exiting script"
    exit 0
  fi
done

# Change rpcpassword
sed -i "s/${OLD_RPC_PASSWORD}/${NEW_RPC_PASSWORD}/" "${BITCOIN_FILE}"

# Change externalip
tor_hostname="$( </tmp/hidden_service/hostname )"
sed -i "s,^\(${EXTERNAL_IP}\).*,\1${tor_hostname}," "${BITCOIN_FILE}"

# Start bitcoin process again
echo "Starting bitcoind process"
sudo -u "${BITCOIN_USER}" bitcoind -daemon >> /dev/null
echo "bitcoind process started"