#!/command/execlineb -P

fdmove -c 2 1


# Get the IP addresses for some NTP servers.
# Limit the DNS queries to 30 seconds: if the DNS is slower than
# that, chances are the server isn't good for us anyway.
# All the queries are parallelized, so it's fast.

pipeline
{
  s6-setuidgid nobody
  forx -Ep I { 0 1 2 }
    s6-dnsip4 -t 30000 -- ${I}.fr.pool.ntp.org
}
importas -u p1 !


# Ask for a NTP exchange with the servers we get.
# If the exchange can't be completed in 5 seconds, kill it.
# All the queries are parallelized.

pipeline
{
  s6-setuidgid ntp
  forstdin -Ep -d"\n" NTPSERVERIP
    s6-sntpclock -T 5000 ${NTPSERVERIP}
}
importas -u p2 !


# Take the first answer we get

pipeline
{
  s6-setuidgid nobody
  s6-head -Sc 12
}
importas -u p3 !


# Update the system clock. Accept 10 minutes of discrepancy.

if { s6-clockadd -e 600000 }


# Success. Send a readiness notification, reap zombies,
# and sleep for 4 hours.

s6-setuidgid nobody
if { fdmove 1 3 s6-echo }
wait { ${p1} ${p2} ${p3} }
s6-sleep 14400
