gfd: fixed logic of atomic writing of the feature file

fix #791 Corrected the incorrect order of operations in atomic writing of the feature file, which could lead to a "permission denied" error observed in the nfd-worker logs

note: now the temporary file is created in $TMPDIR instead of /etc/kubernetes/node-feature-discovery/features.d/gfd-tmp/

Signed-off-by: belo4ya <[email protected]>

go.mod

@@ -8,6 +8,7 @@ require (
 	github.com/NVIDIA/go-nvml v0.12.4-0
 	github.com/NVIDIA/nvidia-container-toolkit v1.16.0
 	github.com/fsnotify/fsnotify v1.7.0
+	github.com/google/renameio v1.0.1
 	github.com/google/uuid v1.6.0
 	github.com/mittwald/go-helm-client v0.12.9
 	github.com/onsi/ginkgo/v2 v2.19.0

go.sum

@@ -162,6 +162,8 @@ github.com/google/gofuzz v1.2.0 h1:xRy4A+RhZaiKjJ1bPfwQ8sedCA+YS2YcCHW6ec7JMi0=
 github.com/google/gofuzz v1.2.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
 github.com/google/pprof v0.0.0-20240424215950-a892ee059fd6 h1:k7nVchz72niMH6YLQNvHSdIE7iqsQxK1P41mySCvssg=
 github.com/google/pprof v0.0.0-20240424215950-a892ee059fd6/go.mod h1:kf6iHlnVGwgKolg33glAes7Yg/8iWP8ukqeldJSO7jw=
+github.com/google/renameio v1.0.1 h1:Lh/jXZmvZxb0BBeSY5VKEfidcbcbenKjZFzM/q0fSeU=
+github.com/google/renameio v1.0.1/go.mod h1:t/HQoYBZSsWSNK35C6CO/TpPLDVWvxOHboWUAweKUpk=
 github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510 h1:El6M4kTTCOh6aBiKaUGG7oYTSPP8MxqL4YI3kZKwcP4=
 github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510/go.mod h1:pupxD2MaaD3pAXIBCelhxNneeOaAeabZDe5s4K6zSpQ=
 github.com/google/uuid v1.1.1/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=

internal/lm/output.go

@@ -22,7 +22,6 @@ import (
 	"fmt"
 	"io"
 	"os"
-	"path/filepath"
 	"strings"
 
 	apiequality "k8s.io/apimachinery/pkg/api/equality"
@@ -32,6 +31,8 @@ import (
 	nfdv1alpha1 "sigs.k8s.io/node-feature-discovery/pkg/apis/nfd/v1alpha1"
 	nfdclientset "sigs.k8s.io/node-feature-discovery/pkg/generated/clientset/versioned"
 
+	"github.com/google/renameio"
+
 	spec "github.com/NVIDIA/k8s-device-plugin/api/config/v1"
 	"github.com/NVIDIA/k8s-device-plugin/internal/flags"
 )
@@ -85,8 +86,8 @@ func (path *toFile) Output(labels Labels) error {
 	if err := output.Output(labels); err != nil {
 		return fmt.Errorf("error writing labels to buffer: %v", err)
 	}
-	err := writeFileAtomically(string(*path), buffer.Bytes(), 0644)
-	if err != nil {
+	// write file atomically
+	if err := renameio.WriteFile(string(*path), buffer.Bytes(), 0644); err != nil {
 		return fmt.Errorf("error atomically writing file '%s': %w", *path, err)
 	}
 	return nil
@@ -102,54 +103,6 @@ func (output *toWriter) Output(labels Labels) error {
 	return nil
 }
 
-func writeFileAtomically(path string, contents []byte, perm os.FileMode) error {
-	absPath, err := filepath.Abs(path)
-	if err != nil {
-		return fmt.Errorf("failed to retrieve absolute path of output file: %v", err)
-	}
-
-	absDir := filepath.Dir(absPath)
-	tmpDir := filepath.Join(absDir, "gfd-tmp")
-
-	err = os.MkdirAll(tmpDir, os.ModePerm)
-	if err != nil && !os.IsExist(err) {
-		return fmt.Errorf("failed to create temporary directory: %v", err)
-	}
-	defer func() {
-		if err != nil {
-			os.RemoveAll(tmpDir)
-		}
-	}()
-
-	tmpFile, err := os.CreateTemp(tmpDir, "gfd-")
-	if err != nil {
-		return fmt.Errorf("fail to create temporary output file: %v", err)
-	}
-	defer func() {
-		if err != nil {
-			tmpFile.Close()
-			os.Remove(tmpFile.Name())
-		}
-	}()
-
-	err = os.WriteFile(tmpFile.Name(), contents, perm)
-	if err != nil {
-		return fmt.Errorf("error writing temporary file '%v': %v", tmpFile.Name(), err)
-	}
-
-	err = os.Rename(tmpFile.Name(), path)
-	if err != nil {
-		return fmt.Errorf("error moving temporary file to '%v': %v", path, err)
-	}
-
-	err = os.Chmod(path, perm)
-	if err != nil {
-		return fmt.Errorf("error setting permissions on '%v': %v", path, err)
-	}
-
-	return nil
-}
-
 const nodeFeatureVendorPrefix = "nvidia-features-for"
 
 type nodeFeatureObject struct {