Re: [9fans] dns

[erik quanstrom]

i'm using a modified version of dns.  i found that aktomi
redirections too unreliable.  even so, i still get crashes, which have
become more frequent in recent weeks.  i've attached a copy of
"restartdns" which is ment to be called from cron on short intervals.

contrib quanstro/ndb has the whole nine yards.

one of these days i will redo dns with a better (and maintainable)
structure.  :-).  but please beat me to it.

- erik
#!/bin/rc
rfork en
nl='
'
mailto=(quanstro)
allow=(ladd)
recursive=()
gcidr = (
        # only blocks that can map to google's a records
        72.14.192.0/18
        74.125.0.0/16
        209.85.128.0/17
        216.239.32.0/19
        173.194.0.0/16
)

if(! ~ `{cat /dev/user} `{cat /dev/hostowner}){
        echo 'restartdns: must be hostowner' >[1=2];
        exit user
}

9fs other

fn syslog{
        echo $sysname `{date} restartdns: $* > /sys/log/dns
}

fn pgroup{
        ifs=$nl g=`{cat /proc/$1/noteid}
        for(i in `{grep -l $g /proc/*/noteid | sed 
's:/proc/([^/]+)/noteid:\1:g'})
                if(test -d /proc/$i)
                        echo $i
}

fn reaper{
        nbroken=()
        for(i in `{ps | awk '$6 == "Broken" && $7 == "dns" {print $2}'}){
                r = /n/other/$user/dnssnap/$sysname.$i.`{date -n}
                snap -o $r `{pgroup $i}
                nbroken = ($nbroken $r)
        }
}

fn getips{
        ndb/dnsquery $* | sed 's/.*[    ]//g'
}

fn google{
        google=()
        if(! ip/cidr -rf <{getips google.com} <{echo $gcidr})
                google=1
        if(ip/cidr -f /lib/badcidr <{getips 9fans.net} )
                google=($google 2)
}

fn why{
        if(! ~ $#nbroken 0){
                echo getting mediæval on $#nbroken broken dns processes.
                for(i in $nbroken)
                        echo $i
        }
        if(! ~ $#nwait 0){
                echo getting mediæval on $#nwait deadlocked dns processes.
                for(i in $nwait)
                        echo $i
        }
        if(! ~ $#google 0){
                echo google broken
                ndb/dnsquery google.com
                ndb/dnsquery 9fans.net any
        }
}

flagfmt='p,f'
args=()
if(! ifs=() eval `{aux/getflags $*} || ! ~ $#* 0){
        aux/usage
        exit usage
}

if(~ $#flagf 0){
        if(! ~ $sysname $allow)
                exit 'wrong system'
        reaper
        ifs=$nl nwait=`{ps -a |sed -n 's/.* +dns \[query lock wait 
for(.*)\]/\1/gp' | sort | uniq -c | awk '$1>2'}
        google

        if(~ $#nbroken 0 && ~ $#nwait 0 && ~ $#google 0)
                exit 'none broken'
        why
        if(~ $service rx)
                {date; echo; why; echo; ps -a | grep ' dns ' }| mail -s 
'restartdns: '^$sysname $mailto
}

if(~ $flagp 1)
        exit ''

syslog slaying broken $#nbroken nwait $#nwait google $#google

dns = ndb/dns
slaydns = `{echo $dns | sed 's:.*/::g'}
slay $slaydns | rc
unmount '#s/dns' /net/dns >[2=]
unmount '#s/dns_net.alt' /net.alt/dns >[2=]
rm -f '#s/dns'  '#s/dns_net.alt'

$dns -N 20000 -s
if(~ $sysname $recursive)
        $dns -sx /net.alt -f /lib/ndb/external
if not
        $dns -Rrsx /net.alt -f /lib/ndb/external