#!/usr/bin/env perl

use strict;
use warnings;

use feature 'say';

use Getopt::Long;
use Data::Dumper;

my ($dryrun) = (0, 0);
my $cgdel_bin = '/usr/bin/cgdelete';
my $cgget_bin = '/usr/bin/cgget';

GetOptions(
	"d|dryrun"         => \$dryrun,
	"h|help"           => sub{ usage() },
);

sub usage {
	say << "EOS";
  [About]
    Script will remove cgroups from users that don't exist on the server anymore

  [Usage]
    usage: $0 [--dryrun]

  [Flags]
    -d, --dryrun  - dryrun, doesnt execute removal
    -h, --help    - help! my hand is stuck in the toaster

  [Example]
    Standard Usage:
      $0

EOS

	exit 1;
}

# Load users from passwd
sub GetMachineUsers {
	my %users;
	my $users_cmd = q(awk -F ":" '{if ($3>=1000) print $1, $3 }' /etc/passwd);
	my $dh_users = `$users_cmd`;
	foreach (split /\n/, $dh_users) {
		my ($user, $uid) = split / /, $_;
		next if $user =~ /root|mysql|Gdnscache|Gdnslog|ansible|nobody/;
		$users{$uid} = $user;
	}
	return %users;
}

# find created cgroups
sub GetUserCgroups {
	my @users;
	my $users_cmd = q(find /sys/fs/cgroup/customer/cpu_*/limits/* -type d | cut -d / -f8);
	my $dh_user = `$users_cmd`;
	foreach (split /\n/, $dh_user) {
		push @users, $_;
	}
	return @users;
}

my %users = GetMachineUsers();
my @users = GetUserCgroups();

for my $user (@users) {
	next if grep { $users{$_} eq $user } keys %users;
	say "User $user no longer exists on the server, need to remove the cgroup for them.";
	my $find_cgroups = `find /sys/fs/cgroup/customer/cpu_*/limits/ -iname $user`;
	if ($find_cgroups) {
		$find_cgroups =~ s/\/sys\/fs\/cgroup\///;
		chomp($find_cgroups);
		say $find_cgroups if $find_cgroups;
		my $controllers = `$cgget_bin -n -v -r cgroup.controllers $find_cgroups`;
		chomp($controllers);
		my @active_controllers = split / /, $controllers;
		# this may error out on other control groups as the first cgroup delete may
		# delete the rest of the control cgroups in that pass
		foreach (@active_controllers) {
			say "$cgdel_bin -g $_:$find_cgroups";
			`$cgdel_bin -g $_:$find_cgroups` unless $dryrun;
		}
	} else {
		say "couldnt find cgroup for $user";
	}
}

say "done";

exit 0;