#!/bin/bash
#
# Increment the spamassassin.org DNS zone's serial number, and trigger
# a zone update against the DNS server.
#
# usage: sudo -u updatesd /home/updatesd/svn/spamassassin/build/jmupdates/tick_zone_serial
#
# required setup, in /etc/sudoers or /opt/sfw/etc/sudoers:
#   updatesd     ALL = NOPASSWD: /usr/sbin/rndc reload

set -x

. /etc/profile

# directory where "counter", "soa_line.tmpl", "soa_line" live.
# it's assumed that the *real* zone $INCLUDEs files from this dir.
# it must be writable by the user this script runs as.
#
soadir=/var/named/jm/yerp.org.d
if [ "$#" -gt 0 ]; then
  soadir="$1"
fi

# ---------------------------------------------------------------------------

# increment the zone serial.  we use a counter, with rollover at 100,
# and a datestamp too.

oldcount=`cat $soadir/counter`

# avoid issues where oldcount=99 and then we can't do any other updates that
# day.  if the old counter was last updated before midnight, reset counter to
# 0.
if perl -e 'use Time::Local; @t=localtime; $mn=timelocal 0,0,0,@t[3..6]; ($mtime) = (stat("'"$soadir"'/counter"))[9]; exit($mn<=$mtime);'; then
  oldcount=-1
fi

newserial=`perl -e '

  my $count = (($ARGV[0] + 1) % 100);
  my @t = localtime time;
  printf "%04d%02d%02d%02d", $t[5]+1900, $t[4]+1, $t[3], $count;

  open (INCR, ">'"$soadir"'/counter") or die "open failed $soadir";
  print INCR $count,"\n"; close INCR or die "close failed $soadir";

' -- $oldcount`

soafile=$soadir/soa_line
touch $soafile
rm -f $soafile.bak \
      $soafile.new

if sed -e 's/__SERIAL__/'"$newserial"'/' \
	< $soafile.tmpl > $soafile.new && \
    [ -s $soafile.new ] && \
    mv $soafile     $soafile.bak && \
    mv $soafile.new $soafile
then
  true
else
  [ -f $soafile.bak ] && mv $soafile.bak $soafile
  echo "failed to create new $soafile" 1>&2 ; exit 1
fi

# figure out the name of the zone
zone=`perl -e '$_=join("", <STDIN>); /^\s*(\S+)/ and print $1' < $soafile`

# trigger a named reload of that changed zone
sudo rndc reload $zone  || exit $?

exit 0