Changeset 10645 in hybrid for branches/releng-9.0/nanobsd/files/tools/nameserver-shuffle

Timestamp:

May 2, 2012, 8:00:55 PM (13 years ago)

Author:

rick

Message:

Make it look good and have it represent its output into /etc/resolv.conf to
avoid confusion why the sorting/shuffling is done.

Related-To: beheer#207

File:

• branches/releng-9.0/nanobsd/files/tools/nameserver-shuffle (modified) (2 diffs)

branches/releng-9.0/nanobsd/files/tools/nameserver-shuffle

@@ -1 @@
-#!/bin/sh
+#!/bin/sh -
 #
 # Shuffle nameservers listed based on the query times, if enabled in
 # resolv.conf. Bare in mind the special syntax.
 #
-# Rick van der Zwet <info@rickvanderzwet.nl>
+# Rick van der Zwet <rick@wirelessleiden.nl>
 #
 
-# ``Random'' sleep between 0 and 30 minutes to avoid ``slamming'' on the DNS door
+# ``Random'' sleep to avoid ``slamming'' on the DNS door
+verbose=true
 if [ "$1" = "cron" ]; then
+  verbose=false
   sleep `expr $$ % 30`
 fi
 
-TAG='^# TAG: DYNAMIC LIST$'
+TAG='^# START DYNAMIC LIST - updated by /tools/nameserver-shuffle$'
+$verbose && echo "# Searching in /etc/resolv.conf for tag '$TAG'"
 
 TDIR=`mktemp -d -t $(basename $0)`
+# Cleanup before going home
+trap "rm -Rf $TDIR; exit 1" 1 2 3 15
+trap "rm -Rf $TDIR; exit 0" 0
+
 DYNLIST=$TDIR/dynlist
 RESULTLIST=$TDIR/resultlist
@@ -20 +27 @@
 
 # Get enabled DYNAMIC LIST nameservers
-sed "1,/$TAG/d" /etc/resolv.conf > $DYNLIST
-NAMESERVERS=`awk '/^nameserver/ {print $2}' $DYNLIST`
+sed "1,\+$TAG+d" /etc/resolv.conf > $DYNLIST || exit 1
+NAMESERVERS=`awk '/^nameserver/ {print $2}' $DYNLIST` || exit 1
 
 # Only do something if we have dynamic nameservers
+$verbose && echo "# Processing" `echo $NAMESERVERS | wc -w` nameservers
 if [ -n "$NAMESERVERS" ]; then
   # Find query times
   for NAMESERVER in $NAMESERVERS; do 
+    $verbose && printf "## Testing nameserver %-16s query time: " $NAMESERVER
     # Strict checking to avoid buggy links to return decent results.
     QUERY_TIME=`dig +time=1 +tries=1 SOA wleiden.net @$NAMESERVER | awk '/Query time:/ {print $4}'`
     # Failed to complete succesfully
-    [ -z "$QUERY_TIME" ] && QUERY_TIME=9999
+    [ -z "$QUERY_TIME" ] && QUERY_TIME="9999"
+    $verbose && echo "$QUERY_TIME"
     echo "$QUERY_TIME $NAMESERVER" >> $RESULTLIST
   done
   
   # Get the header part 
-  sed -n "1,/$TAG/p" /etc/resolv.conf > $NEWRESOLV
+  sed -n "1,\+$TAG+p" /etc/resolv.conf > $NEWRESOLV || exit 1
   
   # Output sorted list
   NAMESERVERS=`sort -n $RESULTLIST | awk '{print $2}'`
   for NAMESERVER in $NAMESERVERS; do
-    grep '\b'$NAMESERVER'\b' $DYNLIST >> $NEWRESOLV
+    QUERY_TIME=`grep $NAMESERVER $RESULTLIST | cut -d' ' -f1`
+    [ $QUERY_TIME = "9999" ] && STATUS="Query time: down" || STATUS="Query time: $QUERY_TIME"
+    # awk magic to get maximum length of comment field (for display purposes).
+    ML=`awk '/^nameserver/ {l=length($4);if (l>ml){ml=l}}END{print ml}' $DYNLIST`
+    # awk magic allows adding or updating of status of nameserver
+    awk '/^nameserver[[:blank:]]+'"$NAMESERVER"'[[:blank:]]*/ {printf "nameserver %-16s # %-'$ML's (%s)\n", $2, $4,"'"$STATUS"'"}' $DYNLIST >> $NEWRESOLV || exit 1
   done
-  
-  cp $NEWRESOLV /etc/resolv.conf
+  $verbose && echo "################################"
+  $verbose && echo "## BEGIN new /etc/resolv.conf ##"
+  $verbose && echo "################################"
+  $verbose && cat $NEWRESOLV
+  $verbose && echo "################################"
+  $verbose && echo "## END new /etc/resolv.conf   ##"
+  $verbose && echo "################################"
+  cp $NEWRESOLV /etc/resolv.conf || exit 1
 fi 
-
-# Cleanup before going home
-rm -Rf $TDIR