#!/bin/sh

help() { cat <</help
Smart wrapper script for the tsocks(8) transparent socksification library
Usage:  ${0##*/} [OPTIONS] [APP [APP ARGS]]
        eval \`${0##*/} -on|-off\`
  -show (or -sh)   Show whether tsocks is set in the environment (\$LD_PRELOAD)
  -debug [level]   Sets debug level (1 if unspecified).  Defaults to 0.
  -lib tsocks-lib  Full path to libtsocks.so
  -c config-file   Use this instead of ~/.tsocks.conf or /etc/tsocks.conf
  -0               No config file (trumps -c), go from scratch (command-line).
  -save [file]     Save these settings to a file (default=~/.tsocks.conf)
  -s server[:port] Specifies the SOCKS server hostname/IP (default=127.0.0.1).
  -p port          Specifies the SOCKS server port number (default=1080).
  -t socks-type    Specifies the SOCKS server type (4 or 5, default=5).
  -u username      Specifies the username for SOCKS 5 authentication.
  -P password      Specifies the password for SOCKS 5 authentication.
  -f (-F reverses) Fallback to direct connection if the SOCKS server is down.
  -l local-net     An IP/Subnet pair (e.g. 10.0.0.0/255.0.0.0) specifying a
                   network to NOT proxy for.  You may use -l multiple times.
  -n "net-conf"    Network path.  Net-conf is a QUOTED collection of arguments
                   for a network range, containing -r, -s, and any of [sptuPf].
  -r remote-net    An IP/Subnet pair (like -l) for within a net-conf scope.
  APP [APP ARGS]   Full command to run with SOCKS (default=${SHELL:-/bin/sh}).
tsocks-wrapper 0.4+20150819, Copyright 2009+ by Adam Katz, GPLv2 (like tsocks)
Part of net-scripts:  https://github.com/adamhotep/net-scripts
/help
}

changelog() { cat <</changelog
  0.1 Rewritten from Debian's tsocks script by Tamas Szerb <toma@rulez.org>
  0.2 Every option in tsocks(8) and tsocks.conf now has an argument.
      Also added -lib, -c, -0, -save, and -debug options.
  0.3 Bugfix to support single-dash args with options but without equals
  0.4 Better trap signals, (mostly failed attempts at) torsocks compatibility
/changelog
}

long_desc() { cat <</long_desc
This script merely sets the environment for the transparent socks config and
then either runs the specified program or dumps the user in a shell.  If
sourced or eval'd, it will set the environment for within the current shell
(as was done by the original script by Tamas Szerb).  This script is far more
powerful because it tweaks the apparent configuration file and allows
specifying alternate files for this use.  The tools used for this purpose are
shell environment variables and the configuration file itself.  See also
https://sourceforge.net/p/tsocks/discussion/54983/thread/66f932a9/
/long_desc
}


s='[	 ]' # match any type of space
err() { echo "${0##*/}: $*" >${TSOCKS_DEBUG_FILE:-/dev/stderr}; }

if [ -z "$TSOCKS_CONF_FILE" ]; then
  TSOCKS_CONF_FILE="$HOME/.tsocks.conf"
  [ -f "$TSOCKS_CONF_FILE" -a -s "$TSOCKS_CONF_FILE" \
    -a -r "$TSOCKS_CONF_FILE" ] # || TSOCKS_CONF_FILE="/etc/torsocks.conf"
  [ -s "$TSOCKS_CONF_FILE" ] || TSOCKS_CONF_FILE="/etc/tsocks.conf"
fi

# Other defaults, which we're leaving blank or as inherited, follow:
# TSOCKS_DEBUG, TSOCKS_DEBUG_FILE, TSOCKS_USERNAME, TSOCKS_PASSWORD
# (see   man 8 tsocks   for more detail)


tsocks_enable() {
  case $LD_PRELOAD in
    *$TSOCKS_LIB*) true ;; # it's already enabled, so this is a no-op
    *) [ -z "$1" ] && export LD_PRELOAD="$TSOCKS_LIB $LD_PRELOAD" ;;
  esac
  # this returns false when tsocks is not loaded AND there is an argument
}

arg() {
  if [ -n "$3" ] && [ "x$1" = "x$3" ]; then
    echo "${2:-/::}"
  else
    echo "$1" |sed -e "s/^--*[^=]*=/-=/" -e "s/^--.[^ ]*//" -e "s/^-.//" \
      |grep . || echo "${2:-/::}"
  fi
}

parse_args() {
 NUM_ARGS=$#
 [ $# = 1 -a -n "$TOP" ] && LONE=true
 while [ "x$1" = "x-${1#?}" ] || [ -n "$LONE" ]; do
  case $1 in
    -show|-sh|--sh|--sho* )
	[ -z "$LONE" ] && err "'$1' must be the sole argument." && exit 1
	echo "tsocks is `tsocks_enable --check || echo 'NOT '`loaded."
	[ -n "$LD_PRELOAD" ] && echo "LD_PRELOAD is '$LD_PRELOAD'"
	exit 0
	;;
    on|-on )
	[ -z "$LONE" ] && err "'$1' must be the sole argument." && exit 1
	[ "$1" = "on" ] && type "$1" >/dev/null 2>&1 && shift && continue
	tsocks_enable
	echo "LD_PRELOAD='$LD_PRELOAD'"
	exit 0
	;;
    off|-off )
	[ -z "$LONE" ] && err "'$1' must be the sole argument." && exit 1
	[ "$1" = "off" ] && type "$1" >/dev/null 2>&1 && shift && continue
	TURN_OFF=true
	;;

    -d*|--debug=*)
	[ -z "$TOP" ] && debug "declaring '$1' inside an '-n' network (huh?)"
	TSOCKS_DEBUG=`arg "$1" "$2" "-debug"`
	# this has an OPTIONAL argument, so we have to check for it here.
	# we also have to ensure we aren't parsing the -0 argument.
	if ! [ "$TSOCKS_DEBUG" != "-0" -a "$TSOCKS_DEBUG" -ge 0 ] 2>/dev/null
	  then TSOCKS_DEBUG=1
	  else [ "$TSOCKS_DEBUG" = "$2" ] && shift
	fi
	;;

    -lib|-lib*=*|--lib*)
	if [ -z "$TOP" ]; then
	  err "Discarding argument '$1' which is invalid inside of an '-n'"
	  shift; continue
	fi
	LIB=`arg "$1" "$2" "-lib"`
	[ -r "$LIB" ] && TSOCKS_LIB="$LIB" && [ "$LIB" = "$2" ] && shift
	;;
    -c*|--conf*=*|--with-conf-file*)
	if [ -z "$TOP" ]; then
	  err "Discarding argument '$1' which is invalid inside of an '-n'"
	  shift; continue
	fi
	CONF=`arg "$1" "$2" "-conf"`
	[ "$CONF" = "$2" ] && shift
	;;
    -0|--0)
	if [ -z "$TOP" ]; then
	  err "Discarding argument '$1' which is invalid inside of an '-n'"
	  shift; continue
	fi
	NO_CONF=true
	;;
    -save|-save*=*|--save*)
	if [ -z "$TOP" ]; then
	  err "Discarding argument '$1' which is invalid inside of an '-n'"
	  shift; continue
	fi
	SAVE=`arg "$1" "$2" "-save"`
	touch "$SAVE" && DO_SAVE=true && [ "$SAVE" = "$2" ] && shift
	;;
    -u*|--user*)
	USR=`arg "$1" "$2" -user`
	[ "$USR" = "$2" ] && shift
	[ "$USR" = "/::" ] && unset USR
	;;
    -P*|-pass|-pass*=*|--pass*)
	PASS=`arg "$1" "$2" -pass`
	[ "$PASS" = "$2" ] && shift
	[ "$PASS" = "/::" ] && unset PASS
	;;
    -s*|--server*|-host|--host*|--server*)
	SERVER=`arg "$1" "$2" -server`
	[ "$SERVER" = "$2" ] && shift
	[ "$SERVER" = "/::" ] && unset SERVER
	;;
    -p*|--port*)
	PORT=`arg "$1" "$2" -port`
	[ "$PORT" = "$2" ] && shift
	;;
    -[45])
        TYPE="${1#-}"
        ;;
    -t*|--type*)
	TYPE=`arg "$1" "$2" -type`
	[ "$TYPE" = "$2" ] && shift
	;;
    -l*|--local*)
	if [ -z "$TOP" ]; then
	  err "Discarding argument '$1' which is invalid inside of an '-n'"
	  shift; continue
	fi
	NEW_LOCAL=`arg "$1" "$2" -local`
	[ "$NEW_LOCAL" = "$2" ] && shift
	[ "$NEW_LOCAL" != "/::" ] && LOCALS="$LOCALS $NEW_LOCAL"
	;;
    -n*|--net*|--path*)
	if [ -z "$TOP" ]; then
	  err "Discarding argument '$1' which cannot be nested in another '-n'"
	  shift; continue
	fi
	NEW_NET=`arg "$1" "$2" -net`
	[ "$NEW_NET" = "$2" ] && shift
	[ "$NEW_NET" != "/::" ] && NETS="$NETS${NETS:+|}$NEW_NET"
	;;
    -r*|--remote*|--reach*)
	if [ -n "$TOP" ]; then
	  err "'-r remote-net' is invalid outside of a '-n'"
	  help; exit 1
	fi
	NEW_REACH=`arg "$1" "$2" -remote`
	[ "$NEW_REACH" = "$2" ] && shift
	[ "$NEW_REACH" != "/::" ] && REACHES="$REACHES $NEW_REACH"
	;;
    -f*) FALLBACK=yes ;;
    -F*) FALLBACK=no ;;
    -- )
	if [ -z "$TOP" ]; then
	  err "Discarding argument '$1' which is invalid inside of an '-n'"
	  shift; continue
	fi
	break
	;;
    -h*|-\?*|--help ) help; exit 0 ;;
    -[Vv]|--[Vv]*|--ver*|--change*)
	help |sed '$!d'
	[ "$1" = "--change${1#--change}" ] && changelog \
	  || echo "See also \`${0##*/} --changelog'"
	exit 0
	;;
    -* )
	err "unrecognized option '$1'" \
	    "\n`help |sed '/^Usage:/!d'`" \
	    "\nTry \`${0##*/} --help for more information."
	exit 1
	;;
    * ) break ;;
  esac
  shift
 done
 [ -n "$TOP" ] && DO_SHIFT=$(($NUM_ARGS-$#))
}

TOP=true
parse_args "$@"
[ "$DO_SHIFT" -gt 0 ] 2>/dev/null && shift $DO_SHIFT
unset TOP

if [ "$TSOCKS_DEBUG" -gt 0 ] 2>/dev/null
  then debug() { echo "$*" >${TSOCKS_DEBUG_FILE:-/dev/stderr}; }
       debug_sed() { sed 's/^/  /' >${TSOCKS_DEBUG_FILE:-/dev/stderr}; }
  else debug() { false; }; debug_sed() { false; }
fi

# Note, TSOCKS_LIB is *not* used by tsocks(8)
# Is the library saved in the config?  (Note, this syntax requires a comment)
if ! [ -r "$TSOCKS_LIB" ]; then
  TSOCKS_LIB=`sed -e "/^#$s*library$s*=$s*/!d" -e s/// -e q "$TSOCKS_CONF_FILE"`
  [ -r "$TSOCKS_LIB" ] && debug "read library file '$TSOCKS_LIB' from config"
fi

# Torsocks does not work with standard SOCKS servers due to its DNS
# Is torsocks available?  That project is still being maintained.
#TORSOCKS="/usr/lib/torsocks/libtorsocks.so"
#if ! [ -r "$TSOCKS_LIB" ] && [ -s "$TORSOCKS" ]; then
#  TSOCKS_LIB="$TORSOCKS"
#fi

# Find the library.  Note, TSOCKS_LIB is *not* used by tsocks(8)
if ! [ -r "$TSOCKS_LIB" ]; then
  IFS_SAVE="$IFS"
  IFS=:
  for ELEMENT in $LD_LIBRARY_PATH; do
    TSOCKS_LIB="${ELEMENT:-.}/libtsocks.so"
    [ -r "$TSOCKS_LIB" ] && break
  done
  IFS="$IFS_SAVE"
  [ -r "$TSOCKS_LIB" ] \
    || TSOCKS_LIB=`locate -r '/libtsocks.so$' 2>/dev/null |head -n1`
  if ! [ -r "$TSOCKS_LIB" ]; then
    err "Can't find libtsocks.so; please install tsocks or use the '-lib' flag."
    exit 1
  fi
fi

debug "tsocks options parsed"
debug "debug=$TSOCKS_DEBUG"
debug "library=$TSOCKS_LIB"

if [ -n "$NO_CONF" ]; then
  debug "Unsetting default and requested configuration files for '-0' argument"
  debug "(TSOCKS_CONF_FILE is no longer set to '$TSOCKS_CONF_FILE')"
  unset CONF
  export TSOCKS_CONF_FILE=/dev/null
elif [ -n "$CONF" ]; then
  if [ -f "$CONF" -a -s "$CONF" -a -r "$CONF" ]
    then TSOCKS_CONF_FILE="$CONF"
    else err "Can't read '$CONF', using default '$TSOCKS_CONF_FILE' instead."
  fi
  debug "Using '$TSOCKS_CONF_FILE' for TSOCKS_CONF_FILE"
fi

if [ -n "$TURN_OFF" ]; then
  debug "Turning off tsocks preloader"
  LD_PRELOAD=`echo -n $LD_PRELOAD |sed "s:$TSOCKS_LIB *::"`
  if [ -n "LD_PRELOAD" ]
    then export LD_PRELOAD; echo "export LD_PRELOAD='$LD_PRELOAD'"
    else unset LD_PRELOAD; echo "unset LD_PRELOAD"
  fi
  exit 0
fi

clean_vars() {
  if [ -z "$PORT" ] && [ "${SERVER##*:}" -gt 0 ] 2>/dev/null; then
    PORT="${SERVER##*:}"
    debug "Extracted port '$PORT' from specified SOCKS server '$SERVER'"
  fi
  SERVER="${SERVER%%:*}"

  if echo "$SERVER" |grep '[^0-9.]' >/dev/null; then
    debug "Server '$SERVER' isn't an IP address.  Converting."
    SRV=`host "$SERVER" 2>/dev/null |sed -e '/.*has address /!d' -e 's///;q'`
    srv_works() { ! echo "${SRV:-fail}" |grep '[^0-9.]' >/dev/null; }
    srv_works || \
      SRV=`dig "$SERVER" 2>/dev/null |sed -e "/.*IN${s}A$s/!d" -e "s///;q"`
    srv_works && SERVER="$SRV"
  fi

  if [ -n "$PORT" ] && ! [ "$PORT" -gt 0 ] 2>/dev/null; then
    err "Discarding invalid SOCKS port '$PORT'"
    unset PORT
  fi
  if [ -n "${TYPE#[45]}" ]; then
    err "Discarding invalid SOCKS type '$TYPE'"
    unset TYPE
  fi
  if [ -n "$FALLBACK" ] && ! [ "$FALLBACK" = "yes" -o "$FALLBACK" = "no" ]; then
    err "Discarding invalid fallback value '$FALLBACK'"
    unset FALLBACK
  fi
}

clean_vars

if [ -n "$USR" ]; then
  debug "TSOCKS_USERNAME='$USR' ${TSOCKS_USERNAME:+(it was $TSOCKS_USERNAME)}"
  TSOCKS_USERNAME="$USR"
fi
if [ -n "$PASS" ]; then
  debug "TSOCKS_PASSWORD='$PASS' ${TSOCKS_PASSWORD:+(it was $TSOCKS_PASSWORD)}"
  TSOCKS_PASSWORD="$PASS"
fi
unset USR PASS


# We have to create a temporary config file to handle some options
if [ -n "$SERVER$PORT$TYPE$LOCALS$NETS$FALLBACK" ]; then
  CONF_ORIG="$TSOCKS_CONF_FILE"
  mktmp() { mktemp 2>/dev/null || echo /tmp/ts$1.$$; }
  CONF_DEFS=`mktmp 1`
  TSOCKS_CONF_FILE=`mktmp 2`
  SIGNALS="0 1 2 9 11 15 TSTP"
  trap "rm -f $CONF_DEFS $TSOCKS_CONF_FILE" $SIGNALS  # cleanup

  trim() { cat "$CONF_ORIG" |sed -e 's/#.*//' -e "$@"; } # trim out comments
  br='/{/,/}/' # match content inside brackets

  echo "# library = $TSOCKS_LIB" >"$TSOCKS_CONF_FILE"

  # import local networks from config
  debug "Importing local networks:"
  trim "${br}d" -e "/^$s*local$s*=/!d" |tee -a "$TSOCKS_CONF_FILE" \
    |debug_sed
  # append local networks from argument(s)
  for NET in $LOCALS; do
    echo "local = $NET" >>"$TSOCKS_CONF_FILE"
    debug "added 'local = $NET' to config"
  done

  # skipping network paths until later so the defaults can get read in

  CONF_SERVER=`trim "${br}d" -e "/^$s*server$s*=$s*/!d"       -e s/// -e '$!d'`
  if [ -z "$SERVER" ]
    then SERVER="${CONF_SERVER:-127.0.0.1}";debug "Using SOCKS server '$SERVER'"
    else debug "Changing server from '$CONF_SERVER' to '$SERVER'"
  fi

  CONF_TYPE=`  trim "${br}d" -e "/^$s*server_type$s*=$s*/!d"  -e s/// -e '$!d'`
  if [ -z "$TYPE" ]
    then TYPE="${CONF_TYPE:-5}"; debug "Using SOCKS type '$TYPE'"
    else debug "Changing type from '$CONF_TYPE' to '$TYPE'"
  fi

  CONF_PORT=`  trim "${br}d" -e "/^$s*server_port$s*=$s*/!d"  -e s/// -e '$!d'`
  if [ -z "$PORT" ]
    then PORT="${CONF_PORT:-1080}"; debug "Using SOCKS port '$PORT'"
    else debug "Changing port from '$CONF_PORT' to '$PORT'"
  fi

  CONF_USER=`  trim "${br}d" -e "/^$s*default_user$s*=$s*/!d" -e s/// -e '$!d'`
  if [ -n "$CONF_USER" ] && [ -n "$TSOCKS_USERNAME" ]
    then debug "Specified user '$TSOCKS_USERNAME' will override '$CONF_USER'"
  fi

  CONF_PASS=`  trim "${br}d" -e "/^$s*default_pass$s*=$s*/!d" -e s/// -e '$!d'`
  if [ -n "$CONF_PASS" ] && [ -n "$TSOCKS_PASSWORD" ]
    then debug "Specified pass '$TSOCKS_PASSWORD' will override '$CONF_PASS'"
  fi

  CONF_FALL=`  trim "${br}d" -e "/^$s*fallback$s*=$s*/!d"     -e s/// -e '$!d'`
  if [ -z "$FALLBACK" ] && [ -n "$CONF_FALL" ]
    then FALLBACK="$CONF_FALL"
    else [ -n "$FALLBACK" ] \
           && debug "Changing fallback from '$CONF_FALL' to '$FALLBACK'"
  fi

  say_setting() { if [ -n "$2" ]; then echo "$1 = $2"; fi; }

  ( # dump defaults to temp file
    say_setting "server"	"$SERVER"
    say_setting "server_type"	"$TYPE"
    say_setting "server_port"	"$PORT"
    say_setting "default_user"	"$TSOCKS_USERNAME"
    say_setting "default_pass"	"$TSOCKS_PASSWORD"
    say_setting "fallback"	"$FALLBACK"
  ) >"$CONF_DEFS"

  unset SERVER PORT TYPE FALLBACK

  # import network paths from config
  debug "Importing network paths:"
  trim "$br!d" |tee -a "$TSOCKS_CONF_FILE" |debug_sed

  IFS_SAVE="$IFS"
  IFS="|" # delimit with pipes for NETS loop
  for NET in $NETS; do
    debug "Parsing net-conf '$NET'"
    IFS="$IFS_SAVE" # delimit with spaces for inside this NET
    parse_args $NET
    clean_vars
    if [ -z "$SERVER" -o -z "$REACHES" ]; then
      err "A net-conf was missing a server or a remote-net.  Skipping."
      continue
    fi
    unset REACH
    (
      echo "path {"
      for REACH in $REACHES; do echo "reaches = $REACH"; done
      echo "server = $SERVER"
      [ -n "$PORT" ] && echo "server_port = $PORT"
      [ -n "$TYPE" ] && echo "server_type = $TYPE"
      [ -n "$FALLBACK" ] && echo "fallback = $FALLBACK"
      echo "}"
      echo ""
    ) |sed 's/^[^{}]*$/\t&/' |tee -a "$TSOCKS_CONF_FILE" |debug_sed
    IFS="|" # revert back to delimiting with pipes for NETS loop
  done
  IFS="$IFS_SAVE" # revert back to default delimiter

  cat "$CONF_DEFS" >>"$TSOCKS_CONF_FILE"

fi

if [ -n "$DO_SAVE" ]; then
  debug "Saving config to '$SAVE'"
  ( echo "# library = $TSOCKS_LIB"
    sed -e "/^#$s*library$s*=$s*./d" "$TSOCKS_CONF_FILE"
  ) >"$SAVE"
fi


# just in case
export TSOCKS_CONF_FILE TSOCKS_DEBUG TSOCKS_DEBUG_FILE
export TSOCKS_USERNAME
#export TSOCKS_PASSWORD

tsocks_enable

# default action (no command given) is to launch a shell
[ $# = 0 ] && set ${SHELL:-/bin/sh}

debug "will run:  exec $@"
debug "debug statements after this one are generated by libtsocks."
debug ""

# if there are signals to clean up (and therefore temp files to remove)
if [ -n "$SIGNALS" ]; then
  (sleep 1 && rm -f $CONF_DEFS $TSOCKS_CONF_FILE && trap - $SIGNALS) &
fi

exec "$@"