#!/bin/bash
# Filename:      terminalserver
# Purpose:       Program to do something
# Authors:       grml-team (grml.org), (c) Michael Gebetsroither <gebi@grml.org>
# Bug-Reports:   see http://grml.org/bugs/
# License:       This file is licensed under the GPL v2.
# Latest change: Sat Aug 06 14:14:40 CEST 2005
################################################################################


###
### __INCLUDES
###
. /etc/grml/sh-lib
#. /etc/grml/sysexits-sh



###
### __VARIABLES
###

FORCE_='false'
verbose_=0

# this file holds all variable definitions
SHARED_PROG_VARS_="/usr/share/grml-terminalserver/shared_prog_vars"
isExistent $SHARED_PROG_VARS_ die
. $SHARED_PROG_VARS_


###
### __FUNCTIONS
###

function printUsage
{
  cat <<EOT
Usage: "$PROG_NAME__" [OPTIONS] <command>

$PROG_NAME__ is the configuration program for the terminalserver
provided by Grml.

COMMANDS:
   help             This help text
   start <service>  Start services (if all services are started, configs will be updated)
   stop <service>   Stop services
   config <service> Update config of given service (or from all if no services given)
   clean            Stop all + remove config and boot files from services
   <default>        interactive

SERVICES:
  tftp        Tftp daemon
  dhcp        Dhcp daemon
  ipt         Iptables setup (snat for clients)
  nfs         All necessary nfs daemons
  <>          ALL services

OPTIONS:
   -v         verbose (show what is going on, v++)
   -h         this help text
   -f         Force

EOT
}

function killPortmapper
{
  if [ -f /etc/init.d/portmap ] ; then
    /etc/init.d/portmap stop >/dev/null &>/dev/null
  elif [ -f /etc/init.d/rpcbind ] ; then
    /etc/init.d/rpcbind stop >/dev/null &>/dev/null
  fi
  killall -9 portmap &>/dev/null
  killall -9 rpcbind &>/dev/null
}

# DHCP SERVICE {{{
function createDhcpConf
{
  if [ -e "$DHCPD_CONFIG_FILE_" ]; then
    if grep $CONFIG_PATTERN_ $DHCPD_CONFIG_FILE_ &>/dev/null; then
      execute "mv -fb \"$DHCPD_CONFIG_FILE_\" \"$DHCPD_CONFIG_FILE_.old\"" eprint &>/dev/null
      execute "source $TEMPLATE_CONFIG_DIR_/dhcpd_config" die
    else
      if [[ $FORCE_ == "true" ]]; then
        execute "mv -fb \"$DHCPD_CONFIG_FILE_\" \"$DHCPD_CONFIG_FILE_.old\"" eprint &>/dev/null
        execute "source $TEMPLATE_CONFIG_DIR_/dhcpd_config" die
      else
        warn "Not updating user edited configfile $DHCPD_CONFIG_FILE_, user -f to override"
      fi
    fi
  else
    execute "source $TEMPLATE_CONFIG_DIR_/dhcpd_config" die
  fi
}

function removeDhcpConf
{
  if [ -e "$DHCPD_CONFIG_FILE_" ]; then
    if grep $CONFIG_PATTERN_ $DHCPD_CONFIG_FILE_ &>/dev/null; then
      rm -f "$DHCPD_CONFIG_FILE_"
    else
      if [[ $FORCE_ == "true" ]]; then
        rm -f "$DHCPD_CONFIG_FILE_"
      else
        warn "Not deleting user edited configfile $DHCPD_CONFIG_FILE_, user -f to override"
      fi
    fi
  fi
}


function stopDhcp
{
  start-stop-daemon --stop --quiet --pidfile "$DHCPD_PID_"
  rm -f $DHCPD_PID_
  # ugly but necessary :-/
  find  /var/lib/dhcp* -type f -name dhcpd.leases -delete
  local dhcpdir
  for dhcpdir in /var/lib/dhcp* ; do
    touch ${dhcpdir}/dhcpd.leases
  done
}

function startDhcp
{
  local conf_file_="$DHCPD_CONFIG_FILE_"

  test -f $DHCPD_BIN_ || die "could not find dhcpd \"$DHCPD_BIN_\""
  start-stop-daemon --start --quiet --pidfile "$DHCPD_PID_" \
    --exec "$DHCPD_BIN_" -- -cf "$conf_file_" -q "$INTERFACE_" || warn "problems starting dhcpd"
}

function runDhcp
{
  isExistent "$DHCPD_CONFIG_FILE_" || \
    warn "no config for dhcpd: \"$DHCPD_CONFIG_FILE_\" => not starting dhcpd" || return 1

  stopDhcp
  sleep 1
  startDhcp
}
# }}}

# IPTABLES {{{
function runIptables
{
  if [[ $IPTABLES_SNAT_ != "true" ]]; then
    return
  fi
  startIptables
}

function startIptables
{
  if [ -x $(command -v iptables) ] ; then
    if [[ $NAT_INTERFACE_ != "" ]]; then
       local nat_source_ip_=`netGetIp "$NAT_INTERFACE_" warn`

       if iptables -t nat -vnL POSTROUTING | grep -q "SNAT.*${NAT_INTERFACE_}.*to:${nat_source_ip_}" ; then
          echo "Rule for SNAT already present, nothing to be done."
       else
          echo "Setting up SNAT for terminalserver clients on ${NAT_INTERFACE_}:"
          echo    "* iptables -t nat -F POSTROUTING"
          echo -n "* iptables -t nat -A POSTROUTING -o $NAT_INTERFACE_ -j SNAT --to-source $nat_source_ip_ ... "
          { iptables -t nat -F POSTROUTING && \
            iptables -t nat -A POSTROUTING -o "$NAT_INTERFACE_" -j SNAT --to-source "$nat_source_ip_" ; } && \
            echo done || echo failed
       fi
       if [ `cat /proc/sys/net/ipv4/ip_forward` -eq 1 ]; then
          echo "IP-Forwarding already enabled, nothing to be done."
       else
          echo -n "Enabling IP-Forwarding: "
          echo 1 > /proc/sys/net/ipv4/ip_forward && echo done || echo failed
       fi
    fi
  else
    warn "iptables executable not available"
  fi
}

function stopIptables
{
  if [[ $IPTABLES_SNAT_ != "true" ]]; then
    return
  fi
  if [ -x $(command -v iptables) ] ; then
    if [[ $NAT_INTERFACE_ != "" ]]; then
       local nat_source_ip_=`netGetIp "$NAT_INTERFACE_" warn`

       if iptables -t nat -vnL POSTROUTING | grep -q "SNAT.*${NAT_INTERFACE_}.*to:${nat_source_ip_}" ; then
         iptables -t nat -F POSTROUTING &>/dev/null && \
           iptables -t nat -D POSTROUTING -o "$NAT_INTERFACE_" -j SNAT --to-source "$nat_source_ip_"
       fi
       echo 0 > /proc/sys/net/ipv4/ip_forward
    fi
  fi
}
# }}}

# TFTP SERVICE {{{
function removeTftpConf
{
  rm -rf $TFTPD_DATA_DIR_/*
}
function createTftpConf
{
  removeTftpConf

  execute "mkdir -p $TFTPD_DATA_DIR_/pxelinux.cfg" die
  if [ -r /usr/lib/PXELINUX/pxelinux.0 ] ; then
    execute "install -m 644 /usr/lib/PXELINUX/pxelinux.0 $TFTPD_DATA_DIR_" die
  else # older versions of syslinux-common (<= 2:4.05+dfsg-6+deb7u1):
    execute "install -m 644 /usr/lib/syslinux/pxelinux.0 $TFTPD_DATA_DIR_" die
  fi
  if [ -d "$MOUNT_POINT_"/boot/release ] ; then
    cp -r "$MOUNT_POINT_"/boot/release "$TFTPD_DATA_DIR_"
  fi
  [ -f "$MEMTEST_IMAGE" ] && execute "install -m 644 $MEMTEST_IMAGE_ $TFTPD_DATA_DIR_/memtest" die
  execute "install -m 644 $PXE_BOOT_MSG_ $TFTPD_DATA_DIR_" die
  [ -f "$PXE_BOOT_LOGO_" ] && execute "install -m 644 $PXE_BOOT_LOGO_ $TFTPD_DATA_DIR_" die

  # PXE / BIOS boot (pxelinux)
  execute "source $TEMPLATE_CONFIG_DIR_/grub-pxelinux_config" die

  # PXE / EFI boot (GRUB)
  execute "source $TEMPLATE_CONFIG_DIR_/grub-shim_config" die
}

function stopTftp
{
  start-stop-daemon --stop --quiet -p "$TFTPD_PID_" --user nobody
}
function startTftp
{
  test -f $TFTPD_BIN_ || die "could not find \"$TFTPD_BIN_\""
  start-stop-daemon --start --quiet --exec "$TFTPD_BIN_" -- --daemon --no-multicast --pidfile "$TFTPD_PID_" --bind-address "$IP_" "$TFTPD_DATA_DIR_" || \
    warn "problems starting tftpd server"
}
function runTftp
{
  stopTftp
  sleep 1
  startTftp
}
# }}}


# NFS  {{{
function createNfsConfig
{
  execute "exportfs -o ro,no_root_squash,async,nohide,fsid=42 $NETWORK_/$NETMASK_:$MOUNT_POINT_" warn
}

function removeNfsConfig
{
  execute "exportfs -u -o ro,no_root_squash,async,nohide,fsid=42 $NETWORK_/$NETMASK_:$MOUNT_POINT_" warn
}

function startNfs
{
  if [ -f /etc/init.d/portmap ] ; then
    /etc/init.d/portmap start
  elif [ -f /etc/init.d/rpcbind ] ; then
    /etc/init.d/rpcbind start
  else
    echo "Warning: Could not start portmapper/rpcbind" >&2
  fi
  /etc/init.d/nfs-common start
  # FIXME /etc/init.d/nfs-kernel-server start
  $USR_SHARE_/nfs-kernel-server start
  echo

  createNfsConfig
}
function stopNfs
{
  removeNfsConfig
  if [[ `exportfs |wc -l` > 0 ]]; then
    dprint "There are other exports, not stopping NFS serivces"
  else
    /etc/init.d/nfs-kernel-server stop >/dev/null 2>&1
    /etc/init.d/nfs-common stop >/dev/null 2>&1
    killPortmapper
  fi
}
# }}}


function createConfig
{
  # FIXME
  execute "sed -i 's/^ALL/\#ALL/' /etc/hosts.deny" warn
  execute "sed -i 's/^ALL : ALL@ALL : DENY/ALL : ALL@ALL : ALLOW/' /etc/hosts.allow" warn

  createTftpConf
  createDhcpConf
}

function actionStart
{
  createConfig

  echo -n "Starting tftpd: "
  runTftp && echo done || echo failed

  echo -n "Starting dhcpd: "
  runDhcp && echo done || echo failed

  runIptables

  echo "Finally starting nfs services..."
  startNfs && echo "Successfully finished startup of grml-terminalserver." || echo 'Startup of grml-terminalserver failed!'
}

function actionStop
{
  stopTftp
  stopDhcp
  stopIptables
  stopNfs
  notice "Terminal-server stopped"
}

function actionClean
{
  actionStop
  removeTftpConf
  removeDhcpConf
  stopNfs
}

function updateConfig
{
  local service_="$1"

  case "$service_" in
    "") createConfig ;;
    tftp) createTftpConf ;;
    dhcp) createDhcpConf ;;
    nfs) removeNfsConfig; createNfsConfig ;;
    *) warn "Service $service_ not available" ;;
  esac
}

# SERVICES {{{
function serviceStart
{
  local service_="$1"   # service to start, if nothing => all

  case "$service_" in
    "") actionStart ;;
    tftp) runTftp ;;
    dhcp) runDhcp ;;
    ipt) startIptables ;;
    nfs) startNfs ;;
    *) warn "Service $service_ not available" ;;
  esac
}

function serviceStop
{
  local service_="$1"   # service to stop, if nothing => all

  case "$service_" in
    "") actionStop ;;
    tftp) stopTftp ;;
    dhcp) stopDhcp ;;
    ipt) stopIptables ;;
    nfs) stopNfs ;;
    *) warn "Service $service_ not available" ;;
  esac
}
# }}}

###
### __MAIN
###

while getopts "fi:hv" opt; do
  case "$opt" in
    f) FORCE_='true' ;;
    h) printUsage; exit ;;
    v) let verbose_=$verbose_+1 ;;
    ?) printUsage; exit 64 ;;
  esac
done
shift $(($OPTIND - 1))  # set ARGV to the first not parsed commandline parameter
setVerbose $verbose_

case "$1" in
  help)   printUsage; exit 0 ;;
esac

checkRoot die "You have to be root to use this program"
disableSyslog

isExistent $DEFAULT_CONFIG_ die
. $DEFAULT_CONFIG_
. $CONFIG_
# used config vars:
# MOUNT_POINT_
# MEMTEST_IMAGE_
# PXE_BOOT_MSG_
# PXE_BOOT_LOGO_
if [[ $MOUNT_POINT_ == "" || $MEMTEST_IMAGE_ == "" || \
  $PXE_BOOT_MSG_ == "" || $PXE_BOOT_MSG_ == "" ]]; then
  warn "MOUNT_POINT_=\"$MOUNT_POINT_\" \
MEMTEST_IMAGE_=\"$MEMTEST_IMAGE_\"
PXE_BOOT_MSG_=\"$PXE_BOOT_MSG_\"
PXE_BOOT_LOGO_=\"$PXE_BOOT_LOGO_\""
  die "False configuration, please update $CONFIG_"
fi

case "$1" in
  clean) actionClean; exit 0 ;;
esac


while true; do
  isExistent "$CONF_FILE_" warn "sorry configfile \"$CONF_FILE_\" not found"
  if [ $? -eq 1 ]; then
    $CONFIG_PROG_ && continue
    $DIALOG_ --clear --backtitle "$BACK_TITLE_" --title "Question" --yesno \
      "grml-terminalserver-config returned an error, do you want to quit now?" 5 75 && exit 1
  else
    break
  fi
done
source $CONF_FILE_

# check for necessary files
check_necessary_files_='no'
if [ "$1" == 'start' ]; then
  case "$2" in
    tftp|"") check_necessary_files_='yes' ;;
  esac
fi
if [ $check_necessary_files_ == 'yes' ]; then
  # test for files absolutely necessary for grml-terminalserver and created from -config
  problem_=0
  for i in $PATH_/initrd.img; do
    isExistent $i warn || problem_=1
  done
  if [ $problem_ -eq 1 ]; then
    die 'Some necessary files are missing, please rerun grml-terminalserver-config, or copy the files manually'
  fi
fi


case "$1" in
  start) serviceStart "$2" ;;
  stop) serviceStop "$2" ;;
  config) updateConfig "$2" ;;
  "")  actionStart ;;
  *)  printUsage ;;
esac

# END OF FILE
################################################################################
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