m/n/time: add time service
This adds a bare-minimum time service based on chrony/NTP for keeping
the system clock and RTC on Metropolis nodes accurate.
It also introduces a UID/GID registry in the Metropolis node code
as this is the first unprivileged service to run on the node itself.
It does not yet use a secure time source, this is tracked as #73.
Change-Id: I873971e6d3825709bc8c696e227bece4cfbda93a
Reviewed-on: https://review.monogon.dev/c/monogon/+/319
Reviewed-by: Sergiusz Bazanski <serge@monogon.tech>
diff --git a/metropolis/node/ids.go b/metropolis/node/ids.go
new file mode 100644
index 0000000..b4ddf84
--- /dev/null
+++ b/metropolis/node/ids.go
@@ -0,0 +1,24 @@
+// Copyright 2021 The Monogon Project Authors.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package node
+
+// These are UID/GID constants for components inside the Metropolis node
+// code.
+const (
+ RootUid = 0
+ TimeUid = 100
+)