fix: use os.Lstat to resolve os.Stat issue in windows

This PR introduces a fallback os.Lstat check in provider client for the
provider socket. There is a known issue in windows using os.Stat() which
happens randomly in 1809, 1903 but always fails in ltsc2022.

Signed-off-by: Anish Ramasekar <anish.ramasekar@gmail.com>

pkg/secrets-store/provider_client.go

@@ -30,6 +30,7 @@ import (
 
 	internalerrors "sigs.k8s.io/secrets-store-csi-driver/pkg/errors"
 	"sigs.k8s.io/secrets-store-csi-driver/pkg/util/fileutil"
+	"sigs.k8s.io/secrets-store-csi-driver/pkg/util/runtimeutil"
 	"sigs.k8s.io/secrets-store-csi-driver/provider/v1alpha1"
 
 	"google.golang.org/grpc"
@@ -134,6 +135,15 @@ func (p *PluginClientBuilder) Get(ctx context.Context, provider string) (v1alpha
 			socketPath = tryPath
 			break
 		}
+		// TODO: This is a workaround for Windows 20H2 issue for os.Stat(). See
+		// microsoft/Windows-Containers#97 for details.
+		// Once the issue is resolved, the following os.Lstat() is not needed.
+		if runtimeutil.IsRuntimeWindows() {
+			if _, err := os.Lstat(tryPath); err == nil {
+				socketPath = tryPath
+				break
+			}
+		}
 	}
 
 	if socketPath == "" {

pkg/secrets-store/server.go

@@ -21,11 +21,12 @@ import (
 	"fmt"
 	"net"
 	"os"
-	"runtime"
 	"strings"
 	"sync"
 	"time"
 
+	"sigs.k8s.io/secrets-store-csi-driver/pkg/util/runtimeutil"
+
 	"github.com/container-storage-interface/spec/lib/go/csi"
 	pbSanitizer "github.com/kubernetes-csi/csi-lib-utils/protosanitizer"
 	"google.golang.org/grpc"
@@ -86,7 +87,7 @@ func (s *nonBlockingGRPCServer) serve(ctx context.Context, endpoint string, ids
 	}
 
 	if proto == "unix" {
-		if runtime.GOOS != "windows" {
+		if !runtimeutil.IsRuntimeWindows() {
 			addr = "/" + addr
 		}
 		if err := os.Remove(addr); err != nil && !os.IsNotExist(err) {

pkg/secrets-store/utils.go

@@ -20,10 +20,10 @@ import (
 	"context"
 	"fmt"
 	"os"
-	"runtime"
 	"strings"
 
 	secretsstorev1 "sigs.k8s.io/secrets-store-csi-driver/apis/v1"
+	"sigs.k8s.io/secrets-store-csi-driver/pkg/util/runtimeutil"
 	"sigs.k8s.io/secrets-store-csi-driver/pkg/util/spcpsutil"
 
 	apierrors "k8s.io/apimachinery/pkg/api/errors"
@@ -57,7 +57,7 @@ func (ns *nodeServer) ensureMountPoint(target string) (bool, error) {
 		return !notMnt, err
 	}
 
-	if runtime.GOOS == "windows" {
+	if runtimeutil.IsRuntimeWindows() {
 		// IsLikelyNotMountPoint always returns notMnt=true for windows as the
 		// target path is not a soft link to the global mount
 		// instead check if the dir exists for windows and if it's not empty

pkg/util/fileutil/atomic_writer.go

@@ -27,10 +27,11 @@ import (
 	"os"
 	"path"
 	"path/filepath"
-	"runtime"
 	"strings"
 	"time"
 
+	"sigs.k8s.io/secrets-store-csi-driver/pkg/util/runtimeutil"
+
 	"k8s.io/apimachinery/pkg/util/sets"
 	"k8s.io/klog/v2"
 )
@@ -195,7 +196,7 @@ func (w *AtomicWriter) Write(payload map[string]FileProjection) error {
 	}
 
 	// (9)
-	if runtime.GOOS == "windows" {
+	if runtimeutil.IsRuntimeWindows() {
 		os.Remove(dataDirPath)
 		err = os.Symlink(tsDirName, dataDirPath)
 		os.Remove(newDataDirPath)

pkg/util/fileutil/writer_test.go

@@ -28,6 +28,7 @@ import (
 	"testing"
 
 	"sigs.k8s.io/secrets-store-csi-driver/pkg/test_utils/tmpdir"
+	"sigs.k8s.io/secrets-store-csi-driver/pkg/util/runtimeutil"
 	"sigs.k8s.io/secrets-store-csi-driver/provider/v1alpha1"
 )
 
@@ -442,7 +443,7 @@ func readPayloads(path string, payloads []*v1alpha1.File) error {
 		if err != nil {
 			return err
 		}
-		if runtime.GOOS == "windows" {
+		if runtimeutil.IsRuntimeWindows() {
 			// on windows only the 0200 bitmask is used by chmod
 			// https://golang.org/src/os/file.go?s=15847:15891#L522
 			if (info.Mode() & 0200) != (fs.FileMode(p.Mode) & 0200) {

pkg/util/runtimeutil/runtime.go

@@ -0,0 +1,24 @@
+/*
+Copyright 2022 The Kubernetes 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 runtimeutil
+
+import "runtime"
+
+// IsRuntimeWindows returns true if the runtime is windows.
+func IsRuntimeWindows() bool {
+	return runtime.GOOS == "windows"
+}