| #!/bin/sh | |
| set -e | |
| # Systemd systems use a systemd timer unit which is preferable to | |
| # run. We want to randomize the apt update and unattended-upgrade | |
| # runs as much as possible to avoid hitting the mirrors all at the | |
| # same time. The systemd time is better at this than the fixed | |
| # cron.daily time | |
| if [ -d /run/systemd/system ]; then | |
| exit 0 | |
| fi | |
| check_power() | |
| { | |
| # laptop check, on_ac_power returns: | |
| # 0 (true) System is on main power | |
| # 1 (false) System is not on main power | |
| # 255 (false) Power status could not be determined | |
| # Desktop systems always return 255 it seems | |
| if which on_ac_power >/dev/null 2>&1; then | |
| if on_ac_power; then | |
| : | |
| elif [ $? -eq 1 ]; then | |
| return 1 | |
| fi | |
| fi | |
| return 0 | |
| } | |
| # sleep for a random interval of time (default 30min) | |
| # (some code taken from cron-apt, thanks) | |
| random_sleep() | |
| { | |
| RandomSleep=1800 | |
| eval $(apt-config shell RandomSleep APT::Periodic::RandomSleep) | |
| if [ $RandomSleep -eq 0 ]; then | |
| return | |
| fi | |
| if [ -z "$RANDOM" ] ; then | |
| # A fix for shells that do not have this bash feature. | |
| RANDOM=$(( $(dd if=/dev/urandom bs=2 count=1 2> /dev/null | cksum | cut -d' ' -f1) % 32767 )) | |
| fi | |
| TIME=$(($RANDOM % $RandomSleep)) | |
| sleep $TIME | |
| } | |
| # delay the job execution by a random amount of time | |
| random_sleep | |
| # ensure we don't do this on battery | |
| check_power || exit 0 | |
| # run daily job | |
| exec /usr/lib/apt/apt.systemd.daily | |