src/PVE/Systemd.pm

   1 package PVE::Systemd;
   2
   3 use strict;
   4 use warnings;
   5
   6 use Net::DBus qw(dbus_uint32 dbus_uint64);
   7 use Net::DBus::Callback;
   8 use Net::DBus::Reactor;
   9
  10 # NOTE: This calls the dbus main loop and must not be used when another dbus
  11 # main loop is being used as we need to wait for the JobRemoved signal.
  12 # Polling the job status instead doesn't work because this doesn't give us the
  13 # distinction between success and failure.
  14 #
  15 # Note that the description is mandatory for security reasons.
  16 sub enter_systemd_scope {
  17     my ($unit, $description, %extra) = @_;
  18     die "missing description\n" if !defined($description);
  19
  20     my $timeout = delete $extra{timeout};
  21
  22     $unit .= '.scope';
  23     my $properties = [ [PIDs => [dbus_uint32($$)]] ];
  24
  25     foreach my $key (keys %extra) {
  26         if ($key eq 'Slice' || $key eq 'KillMode') {
  27             push @{$properties}, [$key, $extra{$key}];
  28         } elsif ($key eq 'CPUShares') {
  29             push @{$properties}, [$key, dbus_uint64($extra{$key})];
  30         } elsif ($key eq 'CPUQuota') {
  31             push @{$properties}, ['CPUQuotaPerSecUSec',
  32                                   dbus_uint64($extra{$key} * 10_000)];
  33         } else {
  34             die "Don't know how to encode $key for systemd scope\n";
  35         }
  36     }
  37
  38     my $job;
  39     my $done = 0;
  40
  41     my $bus = Net::DBus->system();
  42     my $reactor = Net::DBus::Reactor->main();
  43
  44     my $service = $bus->get_service('org.freedesktop.systemd1');
  45     my $if = $service->get_object('/org/freedesktop/systemd1', 'org.freedesktop.systemd1.Manager');
  46     # Connect to the JobRemoved signal since we want to wait for it to finish
  47     my $sigid;
  48     my $timer;
  49     my $cleanup = sub {
  50         my ($no_shutdown) = @_;
  51         $if->disconnect_from_signal('JobRemoved', $sigid) if defined($if);
  52         $if = undef;
  53         $sigid = undef;
  54         $reactor->remove_timeout($timer) if defined($timer);
  55         $timer = undef;
  56         return if $no_shutdown;
  57         $reactor->shutdown();
  58     };
  59
  60     $sigid = $if->connect_to_signal('JobRemoved', sub {
  61         my ($id, $removed_job, $signaled_unit, $result) = @_;
  62         return if $signaled_unit ne $unit || $removed_job ne $job;
  63         $cleanup->(0);
  64         die "systemd job failed\n" if $result ne 'done';
  65         $done = 1;
  66     });
  67
  68     my $on_timeout = sub {
  69         $cleanup->(0);
  70         die "systemd job timed out\n";
  71     };
  72
  73     $timer = $reactor->add_timeout($timeout * 1000, Net::DBus::Callback->new(method => $on_timeout))
  74         if defined($timeout);
  75     $job = $if->StartTransientUnit($unit, 'fail', $properties, []);
  76     $reactor->run();
  77     $cleanup->(1);
  78     die "systemd job never completed\n" if !$done;
  79 }
  80
  81 1;