hooks/dhclient.in

   1 #! /bin/bash
   2
   3 set -eu
   4
   5 LXC_DHCP_SCRIPT="@LXCHOOKDIR@/dhclient-script"
   6 LXC_DHCP_CONFIG="@SYSCONFDIR@/lxc/dhclient.conf"
   7
   8 rootfs_path="${LXC_ROOTFS_PATH#*:}"
   9 hookdir="${rootfs_path/%rootfs/hook}"
  10
  11 conffile_arg=""
  12 if [ -e "${LXC_DHCP_CONFIG}" ]; then
  13     conffile_arg="-cf ${LXC_DHCP_CONFIG}"
  14 fi
  15
  16 debugfile="/dev/null"
  17 if [ "${LXC_LOG_LEVEL}" = "DEBUG" ] || [ "${LXC_LOG_LEVEL}" = "TRACE" ]; then
  18     debugfile="${hookdir}/dhclient.log"
  19     echo "INFO: Writing dhclient log at ${debugfile}." >&2
  20 fi
  21
  22 pidfile="${hookdir}/dhclient.pid"
  23 leasefile="${hookdir}/dhclient.leases"
  24
  25 usage() {
  26     echo "Usage: ${0##*/} <name> lxc {start-host|stop}"
  27 }
  28
  29 dhclient_start() {
  30     ns_args=("--uts" "--net")
  31     if [ -z "$(readlink /proc/${LXC_PID}/ns/user /proc/self/ns/user | uniq -d)" ]; then
  32         ns_args+=("--user")
  33     fi
  34
  35     mkdir -p "${hookdir}"
  36
  37     if [ -e "${pidfile}" ]; then
  38         echo "WARN: DHCP client is already running, skipping start hook." >> "${debugfile}"
  39     else
  40         echo "INFO: Starting DHCP client and acquiring a lease..." >> "${debugfile}"
  41         nsenter ${ns_args[@]} --target "${LXC_PID}" -- \
  42           /sbin/dhclient -1 ${conffile_arg} -pf "${pidfile}" -lf "${leasefile}" -e "ROOTFS=${rootfs_path}" -sf "${LXC_DHCP_SCRIPT}" -v >> "${debugfile}" 2>&1
  43     fi
  44 }
  45
  46 dhclient_stop() {
  47     # We can't use LXC_PID here since the container process has exited,
  48     # use the namespace file descriptors in the hook arguments instead.
  49     ns_args=("")
  50     if [ "${LXC_HOOK_VERSION:-0}" -eq 0 ]; then
  51         for arg in "$@"; do
  52             case "${arg}" in
  53                 uts:* | user:* | net:*) ns_args+=("--${arg/:/=}") ;;
  54                 *) ;;
  55             esac
  56         done
  57     else
  58         ns_args+=("--uts=${LXC_UTS_NS}")
  59         ns_args+=("--net=${LXC_NET_NS}")
  60         [ -n "${LXC_USER_NS:+x}" ] && ns_args+=("--user=${LXC_USER_NS}")
  61     fi
  62
  63     if [ -e "${pidfile}" ]; then
  64         echo "INFO: Stopping DHCP client and releasing leases..." >> "${debugfile}"
  65         nsenter ${ns_args[@]} -- \
  66           /sbin/dhclient -r ${conffile_arg} -pf "${pidfile}" -lf "${leasefile}" -e "ROOTFS=${rootfs_path}" -sf "${LXC_DHCP_SCRIPT}" -v >> "${debugfile}" 2>&1
  67     else
  68         echo "WARN: DHCP client is not running, skipping stop hook." >> "${debugfile}"
  69     fi
  70
  71     # dhclient could fail to release the lease and shutdown, try to cleanup after ourselves just in case.
  72     nsenter ${ns_args[@]} -- \
  73       /bin/sh -c 'pkill --ns $$ --nslist net -f "^/sbin/dhclient"' || true
  74     rm -f "${pidfile}"
  75 }
  76
  77 HOOK_SECTION=
  78 HOOK_TYPE=
  79 case "${LXC_HOOK_VERSION:-0}" in
  80     0) HOOK_SECTION="${2:-}"; HOOK_TYPE="${3:-}"; shift 3;;
  81     1) HOOK_SECTION="${LXC_HOOK_SECTION:-}"; HOOK_TYPE="${LXC_HOOK_TYPE:-}";;
  82     *) echo "ERROR: Unsupported hook version: ${LXC_HOOK_VERSION}." >&2; exit 1;;
  83 esac
  84
  85 if [ "${HOOK_SECTION}" != "lxc" ]; then
  86     echo "ERROR: Not running through LXC." >&2
  87     exit 1
  88 fi
  89
  90 case "${HOOK_TYPE}" in
  91     start-host) dhclient_start $@;;
  92     stop) dhclient_stop $@;;
  93     *) usage; exit 1;;
  94 esac
  95
  96 exit 0