#!/bin/sh
# onionshare-tor: written by Wren Linux extras/onionshare.sh
# OnionShare through a webtunnel bridge. OnionShare's own tor has no way to run webtunnel,
# so with that bridge chosen, onionshare and onionshare-cli in ~/.local/bin are links to
# this, which starts a private tor (the torrc beside its data, in a folder only you can
# open), waits until it is connected, runs the real program, and stops it again.
#
# There is no other way out: the torrc says UseBridges 1, so with the bridge down it stays
# unconnected, and this says so. It never connects directly, and never hands over to
# OnionShare's own tor. The tor ends with this script, however this script ends, and
# killing this script ends the share.
set -u
name=${0##*/}
REAL_DIR=${WREN_ONIONSHARE_REAL:-/usr/bin}
DIR=$HOME/.local/state/wren/onionshare-tor
WAIT=${WREN_ONIONSHARE_WAIT:-600}

fail() {
    echo "$name: $*" >&2
    [ -t 2 ] || notify-send -u critical OnionShare "$*" 2>/dev/null || true
    exit 1
}
case $name in
    onionshare | onionshare-cli) real=$REAL_DIR/$name ;;
    *) echo "usage: run it as onionshare or onionshare-cli (extras/onionshare.sh links them here)" >&2; exit 2 ;;
esac
[ -x "$real" ] || fail "$real is missing. Run: wrenctl install onionshare"
# (these say something and end: no reason to connect to anything)
case ${1:-} in --help | -h | --version | -V) exec "$real" "$@" ;; esac
[ -r "$DIR/torrc" ] || fail "its bridge isn't set up. Run: wrenctl install onionshare"
command -v tor >/dev/null || fail "tor is missing. Run: wrenctl install onionshare"

# One at a time: two tors can't share this one's data
exec 9>"$DIR/lock"
flock -n 9 || fail "OnionShare is running already, through this bridge. Close that one first."

tor_pid=
# shellcheck disable=SC2317,SC2329  # the trap below calls it
stop_tor() {
    if [ -n "$tor_pid" ]; then kill "$tor_pid" 2>/dev/null; wait "$tor_pid" 2>/dev/null; tor_pid=; fi
    rm -f "$DIR/log"
}
trap stop_tor EXIT
trap 'exit 130' INT TERM HUP

: >"$DIR/log"
chmod 600 "$DIR/log"
# (no defaults: only this torrc counts. Owning process: it ends if this script is killed)
tor --defaults-torrc /dev/null -f "$DIR/torrc" --quiet --__OwningControllerProcess "$$" 9>&- &
tor_pid=$!

echo "Connecting to Tor through your webtunnel bridge. This can take a few minutes..."
[ -t 2 ] || notify-send OnionShare "Connecting to Tor through your webtunnel bridge..." 2>/dev/null || true
end=$(($(date +%s) + WAIT))
until grep -q 'Bootstrapped 100%' "$DIR/log"; do
    kill -0 "$tor_pid" 2>/dev/null || { tor_pid=; fail "its tor stopped before it connected. Nothing was shared."; }
    [ "$(date +%s)" -lt "$end" ] ||
        fail "couldn't reach Tor through your bridge in $WAIT seconds, and nothing connected any other way. Nothing was shared. The bridge may be down: wrenctl install onionshare asks for another."
    sleep "${WREN_ONIONSHARE_POLL:-1}"
done

# Beside this script, not in front of it: sh keeps a signal until the program in front
# ends, so killing this would leave the share online. Its keyboard and Ctrl+C stay its
# own (sh takes both from a program started with &).
exec 8<&0
env --default-signal=INT "$real" "$@" <&8 8<&- 9>&- &
real_pid=$!
exec 8<&-
trap 'kill "$real_pid" 2>/dev/null' TERM HUP
# (Ctrl+C reaches OnionShare too: it ends in its own way, and this goes on waiting)
trap : INT
while :; do
    wait "$real_pid"
    rc=$?
    kill -0 "$real_pid" 2>/dev/null || break
done
exit "$rc"