pkg/systemd: move to internal/cri

This pacakge is only used internally in the cri package, which is an internal
packages, so we can make the utility internal as well.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

internal/cri/server/runtime_config_linux.go

@@ -22,7 +22,7 @@ import (
 
 	runcoptions "github.com/containerd/containerd/v2/core/runtime/v2/runc/options"
 	criconfig "github.com/containerd/containerd/v2/internal/cri/config"
-	"github.com/containerd/containerd/v2/pkg/systemd"
+	"github.com/containerd/containerd/v2/internal/cri/systemd"
 	"github.com/containerd/log"
 	runtime "k8s.io/cri-api/pkg/apis/runtime/v1"
 )

internal/cri/server/runtime_config_linux_test.go

@@ -21,7 +21,7 @@ import (
 	"testing"
 
 	criconfig "github.com/containerd/containerd/v2/internal/cri/config"
-	"github.com/containerd/containerd/v2/pkg/systemd"
+	"github.com/containerd/containerd/v2/internal/cri/systemd"
 	"github.com/containerd/containerd/v2/plugins"
 	"github.com/stretchr/testify/assert"
 	runtime "k8s.io/cri-api/pkg/apis/runtime/v1"

internal/cri/systemd/util.go

@@ -0,0 +1,58 @@
+//go:build linux
+
+/*
+   Copyright The containerd Authors.
+
+   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.
+*/
+
+// Copyright 2015 CoreOS, Inc.
+//
+// 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 systemd
+
+import (
+	"os"
+	"sync"
+)
+
+var (
+	runningSystemd bool
+	detectSystemd  sync.Once
+)
+
+// IsRunningSystemd checks whether the host was booted with systemd as its init
+// system. This functions similarly to systemd's `sd_booted(3)`: internally, it
+// checks whether /run/systemd/system/ exists and is a directory.
+// https://github.com/coreos/go-systemd/blob/d843340ab4bd3815fda02e648f9b09ae2dc722a7/util/util.go#L68-L78
+func IsRunningSystemd() bool {
+	detectSystemd.Do(func() {
+		fi, err := os.Lstat("/run/systemd/system")
+		if err != nil {
+			return
+		}
+		runningSystemd = fi.IsDir()
+	})
+	return runningSystemd
+}