Merge pull request #7694 from AkihiroSuda/introspection-pid

introspection: expose the daemon's PID and PIDNS

services/introspection/local.go

@@ -20,6 +20,7 @@ import (
 	context "context"
 	"os"
 	"path/filepath"
+	"runtime"
 	"sync"
 
 	api "github.com/containerd/containerd/api/services/introspection/v1"
@@ -105,8 +106,18 @@ func (l *Local) Server(ctx context.Context, _ *ptypes.Empty, _ ...grpc.CallOptio
 	if err != nil {
 		return nil, errdefs.ToGRPC(err)
 	}
+	pid := os.Getpid()
+	var pidns uint64
+	if runtime.GOOS == "linux" {
+		pidns, err = statPIDNS(pid)
+		if err != nil {
+			return nil, errdefs.ToGRPC(err)
+		}
+	}
 	return &api.ServerResponse{
-		UUID: u,
+		UUID:  u,
+		Pid:   uint64(pid),
+		Pidns: pidns,
 	}, nil
 }
 

services/introspection/pidns_linux.go

@@ -0,0 +1,36 @@
+/*
+   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.
+*/
+
+package introspection
+
+import (
+	"fmt"
+	"os"
+	"syscall"
+)
+
+func statPIDNS(pid int) (uint64, error) {
+	f := fmt.Sprintf("/proc/%d/ns/pid", pid)
+	st, err := os.Stat(f)
+	if err != nil {
+		return 0, err
+	}
+	stSys, ok := st.Sys().(*syscall.Stat_t)
+	if !ok {
+		return 0, fmt.Errorf("%T is not *syscall.Stat_t", st.Sys())
+	}
+	return stSys.Ino, nil
+}

services/introspection/pidns_others.go

@@ -0,0 +1,24 @@
+//go:build !linux
+// +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.
+*/
+
+package introspection
+
+func statPIDNS(pid int) (uint64, error) {
+	return 0, nil
+}