#!/usr/bin/env bash

# - Sets new serial and reloads zone
# -
# - Return (Exit) Codes:
# -    success:
# -       0:    Serial is replaced and Zone is reloaded
# -    error:
# -      10:    Invalid Hostname/Domain given
# -      15:    Hostname/Domain not supported
# -      11:    No zonefile found
# -      12:    Determin new Serial failed
# -      13:    Increasing Serial failed
# -      14:    Reloading Zone failed
# -      99:    Fatal error
# - 
# - usage:   ./nd_set_new_serial.sh <hostname|domain>
# -
# - example: ./nd_set_new_serial.sh a.mx.open.de

# -

## -- Variable definitions
## --

# - Bind configuration file containing zone definitions
# -
ZONE_CONF_FILE=/etc/bind/named.conf.local

BIND_USER=bind
BIND_GROUP=bind

## --
## -- End: Variable definitions

## ***
## *** Don't make changes after this line ***
## ***

## --- some functions
## ---
echononl(){
   echo X\\c > /tmp/shprompt$$
   if [ `wc -c /tmp/shprompt$$ | awk '{print $1}'` -eq 1 ]; then
      echo -e -n "$*\\c" 1>&2
   else
       echo -e -n "$*" 1>&2
   fi
   rm /tmp/shprompt$$
}

fatal(){
   echo ""
   echo -e "[ \033[31m\033[1mError\033[m ]: $*"
   echo ""
   echo -e "\t\033[31m\033[1mScript is canceled\033[m\033[m"
   echo ""
   exit 1
}

warn (){
   echo ""
   echo -e "\t[ \033[33m\033[1mWarning\033[m ]: $*"
   echo ""
}

info (){
   echo ""
   echo -e "\t[ \033[32m\033[1mInfo\033[m ]: $*"
   echo ""
}

ok (){
   echo ""
   echo -e "\t[ \033[36m\033[1mOk\033[m ]: $*"
   echo ""
}

error(){
   echo ""
   echo -e "\t[ \033[31m\033[1mFehler\033[m ]: $*"
   echo ""
}

echo_ok() {
   echo -e "\033[75G[ \033[32mok\033[m ]"
}
echo_failed(){
   echo -e "\033[75G[ \033[1;31mfailed\033[m ]"
}
echo_skipped() {
   echo -e "\033[75G[ \033[33m\033[1mskipped\033[m ]"
}

containsElement () {
   local e
   for e in "${@:2}"; do [[ "$e" == "$1" ]] && return 0; done
   return 1
}

## ---
## --- END: functions

# - Parameter "check" can be used, to test whether this script
# - is accessable (e.g. from a script on a remote host)
# -
if [[ "$1" = "check" ]]; then
   echo "\$1: $1"
   exit 0
fi

host_name=$1


echo ""


# - Validate Syntax of given domain
# -
valid_domain_regex="^([a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9\-]{0,61}[a-zA-Z0-9])(\.([a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9\-]{0,61}[a-zA-Z0-9]))*$"
echononl "\tValidate syntax of given domain.."
if [[ $host_name =~ $valid_domain_regex ]]; then
   if [[ ! $host_name =~ \. ]]; then
       echo_failed
       error "Invalid hostname/domain \"$1\" given!"
       exit 10
   else
      echo_ok
   fi
else
   echo_failed
   error "Invalid hostname/domain ($1) given!"
   exit 10
fi


# - Determin zone (domain)
# -
_failed=false
_host_name=$host_name
_tmp_host_name=$(echo ${_host_name//\./\\.})
while ! grep -e "$_tmp_host_name" $ZONE_CONF_FILE > /dev/null 2>&1 ; do
   _host_name=${_host_name#*.}
   _tmp_host_name=$(echo ${_host_name//\./\\.})
   if [[ ! $_tmp_host_name =~ \. ]]; then
      _failed=true
      break
   fi
done

if $_failed ; then
   error "Given hostname/domain \"$1\" not supported by this nameserver!"
else
   domain=$_host_name
fi


# - Determine zonefile (by reading bind configuration)
# -
_found=false
declare -i _number=0
regex_zone="^[[:space:]]*zone[[:space:]]+\"$_tmp_host_name\""
regex_file="^[[:space:]]*file"
while IFS='' read -r line || [[ -n "$line" ]] ; do
   if [[ $line  =~ $regex_zone ]]; then
      _found=true
   fi
   if $_found ; then
      if [[ $line  =~ $regex_file ]]; then
         zone_file=`echo $line | awk '{print$2}'`
         shopt -s extglob
         if [[ $zone_file =~ \; ]]; then
            zone_file=${zone_file%%*(\;)}
         fi
         if [[ $zone_file =~ ^\" ]]; then
            zone_file=${zone_file##*(\")}
            zone_file=${zone_file%%*(\")}
         fi
         shopt -u extglob
         let number++
         break
      fi
   fi
done < $ZONE_CONF_FILE

zone_file_dir=`dirname $zone_file`

if [[ $number -eq 0 ]] ; then
   error "No Zonefile (master) found for domain \"$domain\" ."
   exit 11
fi


echononl "\tBackup existing directory containg zonefiles.."
if [[ -d "$zone_file_dir" ]] ; then
   cp -a $zone_file_dir ${zone_file_dir}.BAK.`date +%Y-%m-%d-%H%M`
   if [[ $? -eq 0 ]]; then
      echo_ok
   else
      echo_failed
      echo ""
      exit 99
   fi
else
   echo_failed
   error "Zonefile directory not found for domain \"$domain\" ."
   exit 99
fi


# - Determin new serial
# -
echononl "\tDetermin new serial.."
_failed=false
declare -i serial_new=`date +%Y%m%d01`
serial_cur=`grep -e "^\s*[0-9]\{10\}" $zone_file | grep serial | awk '{print$1}'`
if [[ $? -gt 0 ]] ; then
   _failed=true
fi
while [ ! $serial_new -gt $serial_cur ]; do
   let serial_new++
done
if [[ $? -gt 0 ]] ; then
   _failed=true
fi
if $_failed ; then
   echo_failed
   error "Determin Serial failed!"
   exit 12
else
   echo_ok
fi


# - Replace serial with the new one
# -
echononl "\tIncrease serial for zone file \"`basename $zone_file`\".."
perl -i -n -p -e "s#^(\s*)\s$serial_cur(.*)#\1 $serial_new\2#" $zone_file > /dev/null 2>&1
if [[ $? -eq 0 ]]; then
   echo_ok
else
   echo_failed
   error "Increasing Serial failed!"
   exit 13
fi

echo ""
echononl "\tCorrect Owner for $zone_file .."
chown $BIND_USER:$BIND_GROUP $zone_file
if [[ $? -eq 0 ]] ; then
   echo_ok
else
   echo_failed
   exit 99
fi
echononl "\tCorrect permissions on $zone_file .."
chmod 644 $zone_file
if [[ $? -eq 0 ]] ; then
   echo_ok
else
   echo_failed
   exit 99
fi


# - Reload Zone
# -
echononl "\tReloading zone \"$domain\".."
rndc reload $domain > /dev/null 2>&1
if [[ $? -eq 0 ]]; then
   echo_ok
   info "Serial increased and zone reloaded ($domain)"
   exit 0
else
   echo_failed
   error "Increasing Serial failed!"
   exit 13
fi

echo
exit 99