debian/apt.apt-compat.cron.daily

   1 #!/bin/sh
   2
   3 set -e
   4
   5 # Systemd systems use a systemd timer unit which is preferable to
   6 # run. We want to randomize the apt update and unattended-upgrade
   7 # runs as much as possible to avoid hitting the mirrors all at the
   8 # same time. The systemd time is better at this than the fixed
   9 # cron.daily time
  10 if [ -d /run/systemd/system ]; then
  11     exit 0
  12 fi
  13
  14 check_power()
  15 {
  16     # laptop check, on_ac_power returns:
  17     #       0 (true)    System is on main power
  18     #       1 (false)   System is not on main power
  19     #       255 (false) Power status could not be determined
  20     # Desktop systems always return 255 it seems
  21     if which on_ac_power >/dev/null 2>&1; then
  22         on_ac_power
  23         POWER=$?
  24         if [ $POWER -eq 1 ]; then
  25             return 1
  26         fi
  27     fi
  28     return 0
  29 }
  30
  31 # sleep for a random interval of time (default 30min)
  32 # (some code taken from cron-apt, thanks)
  33 random_sleep()
  34 {
  35     RandomSleep=1800
  36     eval $(apt-config shell RandomSleep APT::Periodic::RandomSleep)
  37     if [ $RandomSleep -eq 0 ]; then
  38         return
  39     fi
  40     if [ -z "$RANDOM" ] ; then
  41         # A fix for shells that do not have this bash feature.
  42         RANDOM=$(( $(dd if=/dev/urandom bs=2 count=1 2> /dev/null | cksum | cut -d' ' -f1) % 32767 ))
  43     fi
  44     TIME=$(($RANDOM % $RandomSleep))
  45     sleep $TIME
  46 }
  47
  48 # delay the job execution by a random amount of time
  49 random_sleep
  50
  51 # ensure we don't do this on battery
  52 check_power || exit 0
  53
  54 # run daily job
  55 exec /usr/lib/apt/apt.systemd.daily