add PVE::SystemD module

[pve-common.git] / src / PVE / SystemD.pm

diff --git a/src/PVE/SystemD.pm b/src/PVE/SystemD.pm
new file mode 100644 (file)
index 0000000..a5d9250
--- /dev/null
+++ b/src/PVE/SystemD.pm
@@ -0,0 +1,81 @@
+package PVE::SystemD;
+
+use strict;
+use warnings;
+
+use Net::DBus qw(dbus_uint32 dbus_uint64);
+use Net::DBus::Callback;
+use Net::DBus::Reactor;
+
+# NOTE: This calls the dbus main loop and must not be used when another dbus
+# main loop is being used as we need to wait for the JobRemoved signal.
+# Polling the job status instead doesn't work because this doesn't give us the
+# distinction between success and failure.
+#
+# Note that the description is mandatory for security reasons.
+sub enter_systemd_scope {
+    my ($unit, $description, %extra) = @_;
+    die "missing description\n" if !defined($description);
+
+    my $timeout = delete $extra{timeout};
+
+    $unit .= '.scope';
+    my $properties = [ [PIDs => [dbus_uint32($$)]] ];
+
+    foreach my $key (keys %extra) {
+       if ($key eq 'Slice' || $key eq 'KillMode') {
+           push @{$properties}, [$key, $extra{$key}];
+       } elsif ($key eq 'CPUShares') {
+           push @{$properties}, [$key, dbus_uint64($extra{$key})];
+       } elsif ($key eq 'CPUQuota') {
+           push @{$properties}, ['CPUQuotaPerSecUSec',
+                                 dbus_uint64($extra{$key} * 10_000)];
+       } else {
+           die "Don't know how to encode $key for systemd scope\n";
+       }
+    }
+
+    my $job;
+    my $done = 0;
+
+    my $bus = Net::DBus->system();
+    my $reactor = Net::DBus::Reactor->main();
+
+    my $service = $bus->get_service('org.freedesktop.systemd1');
+    my $if = $service->get_object('/org/freedesktop/systemd1', 'org.freedesktop.systemd1.Manager');
+    # Connect to the JobRemoved signal since we want to wait for it to finish
+    my $sigid;
+    my $timer;
+    my $cleanup = sub {
+       my ($no_shutdown) = @_;
+       $if->disconnect_from_signal('JobRemoved', $sigid) if defined($if);
+       $if = undef;
+       $sigid = undef;
+       $reactor->remove_timeout($timer) if defined($timer);
+       $timer = undef;
+       return if $no_shutdown;
+       $reactor->shutdown();
+    };
+
+    $sigid = $if->connect_to_signal('JobRemoved', sub {
+       my ($id, $removed_job, $signaled_unit, $result) = @_;
+       return if $signaled_unit ne $unit || $removed_job ne $job;
+       $cleanup->(0);
+       die "systemd job failed\n" if $result ne 'done';
+       $done = 1;
+    });
+
+    my $on_timeout = sub {
+       $cleanup->(0);
+       die "systemd job timed out\n";
+    };
+
+    $timer = $reactor->add_timeout($timeout * 1000, Net::DBus::Callback->new(method => $on_timeout))
+       if defined($timeout);
+    $job = $if->StartTransientUnit($unit, 'fail', $properties, []);
+    $reactor->run();
+    $cleanup->(1);
+    die "systemd job never completed\n" if !$done;
+}
+
+1;