logind-sleep-handler.pl

#!/usr/bin/env perl
use warnings;
use strict;
use Net::DBus;
use Net::DBus::Reactor;
use POSIX;

my $inhibit_fd;
my $logind_mgr;

sub pre_suspend {
    system("/usr/bin/psd", "sync");
}

sub take_inhibit {
    if (!defined $inhibit_fd) {
        $inhibit_fd = $logind_mgr->Inhibit("sleep", "psd", "psd wants to sync", "delay");
    }
}

sub drop_inhibit {
    if (defined $inhibit_fd) {
        POSIX::close($inhibit_fd);
        $inhibit_fd = undef;
    }
}

$logind_mgr = Net::DBus->system()
              ->get_service("org.freedesktop.login1")
              ->get_object("/org/freedesktop/login1");

$logind_mgr->connect_to_signal("PrepareForSleep", sub {
    my ($suspending) = @_;
    if ($suspending) {
        pre_suspend();
        drop_inhibit();
    } else {
        take_inhibit();
    }
});

take_inhibit();

Net::DBus::Reactor->main()->run();