#!/bin/sh
#
# Run dhclient, the system DHCP client, with the appropriate parameters for
# SpaceCast.
iface=$1

lock=/var/run/dhclient.$iface.lock
lockfile-create --use-pid $lock

kill_dhclient() {
  for i in $(seq 1 10); do
    # Send TERM to all matching processes.
    pkill -f "$1"
    # Break if all matching processes are killed.
    pgrep -f "$1" || break
    usleep 500000
  done

  # Send KILL to all lingering matching processes.
  pkill -9 -f "$1"
}

run_dhclient() {
  local suffix="$1" xargs="$2"
  local pidfile="/var/run/dhclient$suffix.$iface.pid"
  local leasefile="/var/run/dhclient$suffix.$iface.lease"
  local conffile="/etc/dhclient$suffix.conf"

  if [ -e "$pidfile" ]; then
    # kill sends TERM which should make the babysitter exit gracefully.
    kill $(cat "$pidfile") >/dev/null 2>&1
    rm -f "$pidfile"
  fi
  babysit 60 dhclient "$iface" $xargs \
      -d \
      -pf "$pidfile" \
      -lf "$leasefile" \
      -cf "$conffile" \
      2>&1 | logos "dhclient$suffix.$iface" &
}

# Kill all dhclient and babysit processes for $iface.
kill_dhclient "dhclient $iface -d"

run_dhclient "" ""

# -N -P means to request a delegated prefix AND get a address.
# -S means runs stateless config, requests only the extra information.
# On the network box we only run the stateful version, running both
# interfere with each other.
# TODO(erdi): Disable IPv6 until it is fully supported in App.
#run_dhclient "6" "-N -P -6 --never-gonna-give-you-up 900"

lockfile-remove $lock