privoxy-adblock.sh

#!/bin/sh

sedcmd=${SEDCMD:-sed}
defaultprivoxydir="/usr/local/etc/privoxy"
defaulturl="https://easylist-downloads.adblockplus.org/easylist.txt"


#===  FUNCTION  ================================================================
#          NAME:  cleanup
#   DESCRIPTION:  cleans up after script termination
#    PARAMETERS:  none
#       RETURNS:  none
#===============================================================================
cleanup() {
  trap - INT TERM EXIT
  [ -f "${pidfile}" ] && rm "$pidfile"
  exit
}

#===  FUNCTION  ================================================================
#          NAME:  isrunning
#   DESCRIPTION:  is any previous instance of this script already running
#    PARAMETERS:  pid file path
#       RETURNS:  boolean
#===============================================================================
isrunning() {
  pidfile="${1}"
  [ ! -f "${pidfile}" ] && return 1  #pid file is nonexistent
  procpid=$(cat "${pidfile}")
  [ -z "${procpid}" ] && return 1  #pid file contains no pid
  # check process list for pid existence and is an instance of this script
  [ ! "$(ps -p "${procpid}" | grep "$(basename "${0}")")" = "" ] && value=0 || value=1
  return ${value}
}

#===  FUNCTION  ================================================================
#          NAME:  createpidfile
#   DESCRIPTION:  atomic creation of pid file with no race condition
#    PARAMETERS:  the pid to put in the file, the filename to use as a lock
#       RETURNS:  none
#===============================================================================
createpidfile() {
  mypid=${1}
  pidfile=${2}
  #Close stderr, don't overwrite existing file, shove my pid in the lock file.
  (exec 2>&-; set -o noclobber; echo "$mypid" > "$pidfile")
  [ ! -f "${pidfile}" ] && exit #Lock file creation failed
  procpid=$(cat "${pidfile}")
  [ "${mypid}" -ne "${procpid}" ] && {
    #I'm not the pid in the lock file
    # Is the process pid in the lockfile still running?
    isrunning "${pidfile}" || {
      # No.  Kill the pidfile and relaunch
      rm "${pidfile}"
      "$0" "$@"
    }
    exit
  }
}

#===  FUNCTION  ================================================================
#          NAME:  pidfilename
#   DESCRIPTION:  create a predictable pid file name, put it in the right inode
#    PARAMETERS:  none
#       RETURNS:  path and filename
#===============================================================================
pidfilename() {
  myfile=$(basename "$0" .sh)
  whoiam=$(whoami)
  mypidfile="/tmp/${myfile}.pid"
  [ "$whoiam" = 'root' ] && mypidfile="/var/run/$myfile.pid"
  echo "$mypidfile"
}

#===  FUNCTION  ================================================================
#          NAME:  doconvert
#   DESCRIPTION:  download requested scripts and perform the conversion
#    PARAMETERS:  privoxy conf dir, list of urls
#       RETURNS:  none
#===============================================================================
doconvert() {
  privoxydir=$1
  urls=$2
  for url in ${urls}
  do
    file="${tempdir}/$(basename "${url}")"
    actionfile="${file%\.*}.script.action"
    filterfile="${file%\.*}.script.filter"
    list="$(basename "${file%\.*}")"

    # clean up files
    [ -f "${file}" ] && rm "${file}"
    [ -f "${actionfile}" ] && rm "${actionfile}"
    [ -f "${filterfile}" ] && rm "${filterfile}"

    echo "downloading ${url} ..."
    if command -v curl >/dev/null; then
        curl -k "${url}" > "${file}"
    elif command -v wget >/dev/null; then
        wget -t 3 --no-check-certificate -O "${file}" "${url}"
    else
        echo "No curl or wget" 1>&2
        exit 255
    fi

    [ "$(grep -E '^.*\[Adblock.*\].*$' "${file}")" = "" ] && echo "The list recieved from ${url} isn't an AdblockPlus list. Skipped" && continue

    echo "Creating actionfile for ${list} ..."
    printf '{ +block{%s} }\n' "${list}" > "${actionfile}"
    $sedcmd '/^!.*/d;1,1 d;/^@@.*/d;/\$.*/d;/#/d;s/\./\\./g;s/\?/\\?/g;s/\*/.*/g;s/(/\\(/g;s/)/\\)/g;s/\[/\\[/g;s/\]/\\]/g;s/\^/[\/\&:\?=_]/g;s/^||/\./g;s/^|/^/g;s/|$/\$/g;/|/d' "${file}" >> "${actionfile}"

    echo "... creating filterfile for ${list} ..."
    echo "FILTER: ${list} Tag filter of ${list}" > "${filterfile}"
    $sedcmd '/^#/!d;s/^##//g;s/^#\(.*\)\[.*\]\[.*\]*/s@<([a-zA-Z0-9]+)\\s+.*id=.?\1.*>.*<\/\\1>@@g/g;s/^#\(.*\)/s@<([a-zA-Z0-9]+)\\s+.*id=.?\1.*>.*<\/\\1>@@g/g;s/^\.\(.*\)/s@<([a-zA-Z0-9]+)\\s+.*class=.?\1.*>.*<\/\\1>@@g/g;s/^a\[\(.*\)\]/s@<a.*\1.*>.*<\/a>@@g/g;s/^\([a-zA-Z0-9]*\)\.\(.*\)\[.*\]\[.*\]*/s@<\1.*class=.?\2.*>.*<\/\1>@@g/g;s/^\([a-zA-Z0-9]*\)#\(.*\):.*[:[^:]]*[^:]*/s@<\1.*id=.?\2.*>.*<\/\1>@@g/g;s/^\([a-zA-Z0-9]*\)#\(.*\)/s@<\1.*id=.?\2.*>.*<\/\1>@@g/g;s/^\[\([a-zA-Z]*\).=\(.*\)\]/s@\1^=\2>@@g/g;s/\^/[\/\&:\?=_]/g;s/\.\([a-zA-Z0-9]\)/\\.\1/g' "${file}" >> "${filterfile}"
    echo "... filterfile created - adding filterfile to actionfile ..."
    echo "{ +filter{${list}} }" >> "${actionfile}"
    echo "*" >> "${actionfile}"
    echo "... filterfile added ..."

    echo "... creating and adding whitlist for urls ..."
    echo "{ -block }" >> "${actionfile}"
    $sedcmd '/^@@.*/!d;s/^@@//g;/\$.*/d;/#/d;s/\./\\./g;s/\?/\\?/g;s/\*/.*/g;s/(/\\(/g;s/)/\\)/g;s/\[/\\[/g;s/\]/\\]/g;s/\^/[\/\&:\?=_]/g;s/^||/\./g;s/^|/^/g;s/|$/\$/g;/|/d' "${file}" >> "${actionfile}"
    echo "... created and added whitelist - creating and adding image handler ..."

    echo "{ -block +handle-as-image }" >> "${actionfile}"
    $sedcmd '/^@@.*/!d;s/^@@//g;/\$.*image.*/!d;s/\$.*image.*//g;/#/d;s/\./\\./g;s/\?/\\?/g;s/\*/.*/g;s/(/\\(/g;s/)/\\)/g;s/\[/\\[/g;s/\]/\\]/g;s/\^/[\/\&:\?=_]/g;s/^||/\./g;s/^|/^/g;s/|$/\$/g;/|/d' "${file}" >> "${actionfile}"
    echo "... created and added image handler ..."
    echo "... created actionfile for ${list}."

    actionfiledest="${privoxydir}/$(basename "${actionfile}")"
    echo "... copying ${actionfile} to ${actionfiledest}"
    cp "${actionfile}" "${actionfiledest}"
    filterfiledest="${privoxydir}/$(basename "${filterfile}")"
    echo "... copying ${filterfile} to ${filterfiledest}"
    cp "${filterfile}" "${filterfiledest}"
  done
}

#===  FUNCTION  ================================================================
#          NAME:  usage
#   DESCRIPTION:  prints command usage
#    PARAMETERS:  none
#       RETURNS:  none
#===============================================================================
usage() {
# echo "Usage: ${0} [-d] [-p <privoxy config dir>] [-u <url1>] [-u <url2>]..."
  echo "Usage: ${0} [-p <privoxy config dir>] [-u <url1>] [-u <url2>]..."
  exit 1
}

#===  FUNCTION  ================================================================
#          NAME:  main
#   DESCRIPTION:  main script entry point
#    PARAMETERS:  none
#       RETURNS:  none
#===============================================================================
main() {
  pidfile="$(pidfilename)"

  tempfile="$(mktemp -t j.XXX)"
  tempdir="$(dirname "${tempfile}")"
  rm "${tempfile}"

  isrunning "${pidfile}" && {
    echo "$(basename "${0}") is already running"
    exit 1
  }

  createpidfile $$ "${pidfile}"
  trap 'cleanup' INT TERM EXIT
# debug="false"
# trap 'logger -t $0 -i -- $USER : $BASH_COMMAND' ERR  #log errors regardless

  privoxydir=$defaultprivoxydir
  urls="${defaulturl}"
  while getopts "dp:u:" opt; do
    case "${opt}" in
      p)
        privoxydir=${OPTARG}
        ;;
      u)
        urls=$(printf '%s\n%s' "${urls}" "${OPTARG}")
        ;;
#     d)
#       debug="true"
#       ;;
      *)
        usage
        ;;
      :)
        echo "Option -${OPTARG} requires an argument." >&2
        usage
        ;;
    esac
  done

# [ "${debug}" = "true" ] && trap 'logger -t $0 -i -- $USER : $BASH_COMMAND' DEBUG #syslog everything if we're debugging
  [ ! -d "${privoxydir}" ] && usage
  [ "${urls}" = "" ] && usage

  # perform the operation
  doconvert "$privoxydir" "$urls"
}

main "$@"

exit 0