nsd-dynipwatch.sh

   1 #!/bin/bash
   2
   3 zonefile=$1
   4 host=$2
   5 watchfile=$3
   6
   7
   8 function getAddrFromZonefile # <host> <zonefile>
   9 {
  10         egrep "^$1\\s.*\\sA\\s.*" $2 | egrep -o "([0-9]+\.)+[0-9]+"
  11 }
  12
  13 function setAddrInZonefile # <host> <zonefile> <addr>
  14 {
  15         sed -i -e "s_^\\($1\\s.*A\\s.*\\s\\)\\([0-9]\\+\\.\\)\\+[0-9]\\+_\\1$3_g" "$2"
  16 }
  17
  18 function getSerialFromZonefile # <zonefile>
  19 {
  20         awk '/; serial/{print$1}' "$1"
  21 }
  22
  23 function setSerialInZonefile # <zonefile> <serial>
  24 {
  25         sed -i -e "s_^\\(.*\\s\\)[0-9]\+\\(\\s\\+; serial.*\\)_\\1$2\\2_g" "$1"
  26 }
  27
  28 while true; do
  29         inotifywait -q -e close_write "${watchfile}"
  30         oldip=`getAddrFromZonefile "${host}" "${zonefile}"`
  31         newip=`cat ${watchfile}`
  32         echo -n "`date '+%a %F %T'` :: ${oldip} => ${newip}."
  33
  34         if ! [ "${oldip}" = "${newip}" ]; then
  35                 serial=`getSerialFromZonefile "${zonefile}"`
  36                 serial=$(( $serial + 1))
  37                 echo -n " Update IP address. New serial ${serial}."
  38                 setAddrInZonefile "${host}" "${zonefile}" "${newip}"
  39                 setSerialInZonefile "${zonefile}" "${serial}"
  40                 nsdc rebuild && nscd reload && nscd notify
  41         fi
  42         echo ""
  43 done
  44
  45