Skip to content

Latest commit

 

History

History
40 lines (28 loc) · 2.67 KB

contest.md

File metadata and controls

40 lines (28 loc) · 2.67 KB
Raw

Scheduled Commands for Contests

Around the contest time, various commands will be executed to:

  • make sure the contestants start the contest with a fresh home directory, and
  • isolate the contestants from the internet.

The commands are executed by via sbin/atrun.sh, which is based on atd scheduler. However, when something happens, admins can also remotely execute the commands manually.

Schedule file

The schedule is located here: misc/schedule2.txt.

When the VM boots up, it will try to fetch a new schedule hosted on the configuration server (https://$POP_SERVER$/config/schedule2.txt). For more details, check misc/rc.local -> sbin/startatd.sh -> sbin/checkschedule.sh.

The schedule file has the following format, with time formatted as YYYY-mm-dd HH:MM

<start-time> <end-time> <next-if-missed> <shell-command>

For example,

2020-09-13 19:00 2020-09-14 00:00 3 /opt/ioi/sbin/contest.sh prep 0

means that the command will be executed only once between 2020-09-13 19:00 and 2020-09-14 00:00. If it is missed to execute the job, it may skip the command and directly execute the 3rd command (3rd line).

Commands

The main contest-related script is here: sbin/contest.sh.

  1. contest lock disables login as ioi user before the contest starts ("locks" the contestant). Usually this will be executed remotely to all contestant VMs.

  2. contest prep <cid> cleans up the VM by recreating the ioi user and removes all contestant-related generated data. This also starts the firewall and creates a file indicating that a contest is running (in "lockdown" mode). The <cid> itself is an unique contest identifier (unrelated to CMS contest id). Afterwards, the VM will be unlocked.

  3. contest unlock reenables login as ioi user ("unlocks" the contestant). This is already included as part of prep above, but admins may manually execute this remotely if for any reason a contestant VM is not unlocked yet.

  4. contest start starts the keylogger and the cron job for contest monitoring (see below).

  5. contest monitor is a command that will be executed every minute by a cron job. It will back up the home directory (only if autobackup is enabled) and will capture some data for monitoring purposes:

    • full-screen screenshots (taken every minute but with 50% probability)
    • monitor resolution (checked every minute and will report any changes to local0 facility)

  6. contest stop stops the keylogger and the cron job.

  7. contest done disables the lockdown mode by turning off the firewall and removing the lockdown indicator file.