Handling of zone transfers and notify messages

[Miek Gieben]

[On 19 Oct, @ 12:07, Måns wrote in "Re: Handling of zone transfers ..."]
> This is a good summary. 
> 
> While we are summarizing, zonec must also bypass broken data as defined
> above, dealing with it as defined above, but not have one such broken zone
> show-stop the entire NSD instance. (Yeah, I know, I wrote exactly that in
> my last mail but I find it missing above. Sorry for the repetititititions.)

the following patch for nsdc.sh.in does the following:

* it axfr's the zone - if this fails it emits a warning
* then it tries to compile to the zone - if this fails another warning
  is given

If both the axfr & compilation have completed succesfully then the 
database for nsd is rebuild. In all other cases the current version
of the zones/database is used.

Note1: each zone that is axfr-ed is compiled twice
Note2: aux. files are used: $zone.axfr (for the axfr) and
       $zone.axfr.db for the test compile

Index: nsdc.sh.in
===================================================================
RCS file: /cvs/nsd/nsdc.sh.in,v
retrieving revision 1.31
retrieving revision 1.30.2.2
diff -u -r1.31 -r1.30.2.2
--- nsdc.sh.in	28 Jul 2004 11:52:31 -0000	1.31
+++ nsdc.sh.in	19 Oct 2004 10:00:40 -0000	1.30.2.2
@@ -3,6 +3,7 @@
 # nsdc.sh -- a shell script to manage the beast
 #
 # Alexis Yushin, <alexis at nlnetlabs.nl>
+# Miek Gieben, <miekg at nlnetlabs.nl>
 #
 # Copyright (c) 2001-2004, NLnet Labs. All rights reserved.
 #
@@ -69,7 +70,6 @@
 #
 # You sure heard this many times before: NO USER SERVICEABLE PARTS BELOW
 #
-
 signal() {
 	if [ -s ${pidfile} ]
 	then
@@ -133,7 +133,28 @@
  				tsiginfoarg="-T ${keysdir}/${masters}.tsiginfo.$$"
 			fi
 
-			$namedxfer -z $zone -f ${zonesdir}/$file ${tsiginfoarg} -s $serial $masters
+			# AXFR to a temp file $file.axfr
+			$namedxfer -z $zone -f ${zonesdir}/$file.axfr ${tsiginfoarg} -s $serial $masters
+			if [ $? -ne 0 ]
+			then
+				if [ -f ${zonesdir}/$file.axfr ]
+				then
+					# axfr succeeded
+					# test compile the zone to see what happens
+					cat ${zonesdir}/$file.axfr | ${sbindir}/zonec -o ${zone} -f ${zonesdir}/$file.axfr.db - 2>/dev/null
+					if [ $? -eq 1 ]
+					then
+						echo "Warning: AXFR of $zone did not compile"
+						rm -f ${zonesdir}/$file.axfr
+					else
+						# we succeed
+						mv -f ${zonesdir}/$file.axfr ${zonesdir}/$file
+					fi
+					rm -f ${zonesdir}/$file.axfr.db
+				else
+					echo "Warning: AXFR for $zone failed"
+				fi
+			fi
 
 			# Do we need to rebuild the database?
 			if [ ${zonesdir}/$file -nt ${dbfile} ]