#!/bin/bash
#-----------------------------------------------------------------------
# /var/install/bin/samba-winshook - trigger actions, if wins.dat changed
#
# Copyright (c) 2002-2013 Thomas Bork, tom(at)eisfair(dot)net
#
# Creation   : 2006-01-01 tb/jv
#
# With idees from Stephen Rothwell <sfr@linuxcare.com> and
# Rod Smith <rodsmith@rodsbooks.com>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#-----------------------------------------------------------------------
if [ $# -lt 4 ]
then
   {
    echo "Usage: $0 op name type ttl [ip_addr ...]"
    echo "       op is one of add, refresh, delete"
    echo "       name is the NETBIOS name"
    echo "       type is the NETBIOS name type"
    echo "       ttl is the NETBIOS time to live"
    echo "       ip_addr's are the remaining IP addresses for this name"
   } 1>&2
    exit 1
fi

op=$1
name=$2
type=$3
wins_ttl=$4
shift 4
ip_addrs="$@"
dns_server_ip='127.0.0.1'
ttl=3600
hostname=`echo $HOSTNAME | tr 'a-z' 'A-Z'`
do_update='no'
logfile='/var/log/log.winshook'
log='no'
delay='60'

# The name of a cache file to use to avoid continual updates
# of the same name and IP addresses.  If you comment this out
# then the cache is not kept at all.
cache_file=/var/lock/samba/wins_update.cache

# NETBIOS name types that we want to create DNS records for:
#    20 is server
#    00 is workstation
#    03 is user
useful_types='20 00 03'

if [ "$log" = "yes" ]
then
    echo "`date +"%d.%m.%Y %H:%M:%S"`: op is $op, name is $name, type is $type" >>"$logfile"
fi

for i in $useful_types
do
    if [ "$type" = "$i" ]
    then
        do_update='yes'
        if [ "$log" = "yes" ]
        then
            echo "`date +"%d.%m.%Y %H:%M:%S"`: useful type $type, performing action..." >>"$logfile"
        fi
    fi
done

if [ "$do_update" = "no" ]
then
    if [ "$log" = "yes" ]
    then
        echo "`date +"%d.%m.%Y %H:%M:%S"`: no useful type $type, exiting..." >>"$logfile"
    fi
    exit 0
fi

if [ ! -f "$cache_file" ]
then
    >"$cache_file"
fi

# check cache file
if [ ! -n "$cache_file" -o ! -r "$cache_file" ]
then
    if [ "$log" = "yes" ]
    then
        echo "`date +"%d.%m.%Y %H:%M:%S"`: cache file $cache_file don't exists or isn't readable, exiting..." >>"$logfile"
    fi
    exit 1
fi

add_change_cacheentry ()
{
    # check if entry exists
    if [ "$log" = "yes" ]
    then
        echo "`date +"%d.%m.%Y %H:%M:%S"`: checking for cache entry $name..." >>"$logfile"
    fi

    if [ ! -z "`fgrep -q -x -i '${name};${ip_addrs}' $cache_file`" ]
    then
        if [ "$log" = "yes" ]
        then
            echo "`date +"%d.%m.%Y %H:%M:%S"`: cache entry $name exists, exiting..." >>"$logfile"
        fi
        exit 0
    fi

    # add or update cache file
    if [ "$log" = "yes" ]
    then
        echo "`date +"%d.%m.%Y %H:%M:%S"`: adding or updating cache entry for $name..." >>"$logfile"
    fi
    grep -vi "^${name};" "$cache_file" >"$cache_file".$$
    echo "${name};${ip_addrs}" >>"$cache_file".$$
}

delete_cacheentry ()
{
    # remove from cache file
    if [ "$log" = "yes" ]
    then
        echo "`date +"%d.%m.%Y %H:%M:%S"`: deleting cache entry for $name..." >>"$logfile"
    fi
    grep -vi "^${name};" "$cache_file" >"$cache_file".$$
}

#-----------------------------------------------------------------------
# add or change DNS entry
#-----------------------------------------------------------------------
add_change_dns ()
{
    # add or change DNS service
    if [ "$log" = "yes" ]
    then
        echo "`date +"%d.%m.%Y %H:%M:%S"`: adding or changing dns entry for $name..." >>"$logfile"
    fi

   {
    echo "server $dns_server_ip"
    echo "update delete ${name}.${DOMAIN_NAME}."
    for i in $ip_addrs
    do
        echo "update add ${name}.${DOMAIN_NAME}. $ttl A $i"
    done
    echo
   } 2>/dev/null | "$nsupdate" >/dev/null 2>&1 &
}

#-----------------------------------------------------------------------
# delete DNS entry
#-----------------------------------------------------------------------
delete_dns ()
{
    # remove from DNS service
    if [ "$log" = "yes" ]
    then
        echo "`date +"%d.%m.%Y %H:%M:%S"`: deleting dns entry for $name..." >>"$logfile"
    fi
   {
    echo "server $dns_server_ip"
    echo "update delete ${name}.${DOMAIN_NAME}."
    echo
   } 2>/dev/null | "$nsupdate" >/dev/null 2>&1 &
}

case $op in
delete)
    delete_cacheentry
    ;;
*)
    add_change_cacheentry
    ;;
esac

# complete cache file and make backup
mv "$cache_file" "$cache_file".old 2>/dev/null
mv "$cache_file".$$ "$cache_file"

# Read samba configuration
. /etc/config.d/cui-samba
if [ "$SAMBA_WINSHOOK_MESSAGE_SEND" = "yes" ]
then
    if [ "$op" = "add" -a -n "$name" -a "$name" != "$hostname" -a "$type" = "20" ]
    then
        if [ "$log" = "yes" ]
        then
            echo "`date +"%d.%m.%Y %H:%M:%S"`: sending message to $name in $delay seconds..." >>"$logfile"
        fi
        /var/install/bin/samba-winshook-netsend "$name" "$SAMBA_WINSHOOK_MESSAGE" "$delay" "$log" "$logfile" &
    fi
fi

if [ "$SAMBA_WINSHOOK_DNSUPDATE" = "yes" ]
then
    nsupdate='/usr/bin/nsupdate'
    if [ ! -f "$nsupdate" ]
    then
        if [ "$log" = "yes" ]
        then
            echo "`date +"%d.%m.%Y %H:%M:%S"`: cannot find nsupdate." >>"$logfile"
        fi
        exit 1
    fi

    # Read DOMAIN_NAME
    . /etc/config.d/base

    # start operation
    case $op in
    delete)
        delete_dns
        ;;
    *)
        add_change_dns
        ;;
    esac
fi

exit 0