support inTree removal scenario for nodes without .ko files

Modprobe will fail with error in case it cannot find an appropriate
.ko file when asked to remove a kernel module. With in-tree removal
scenario, modporbe search path is /lib/modules on the host, and not
the worker image.
This PR contains the following:
1) Adding FileExists function that check the presence of a file under
   a search path based on a regexp
2) in worker flow, in case in-tree removal scenario is requisted, worker
   will verify if the requested .ko file(s) are present on the host,
   remove from the request missing files and will proceed with the
   removal scenario for the rest
3) unit-test

Author: yevgeny-shnaidman

internal/utils/filesystem_helper.go

@@ -2,8 +2,10 @@ package utils
 
 import (
 	"fmt"
+	"io/fs"
 	"os"
 	"path/filepath"
+	"regexp"
 
 	"github.com/go-logr/logr"
 )
@@ -12,6 +14,7 @@ import (
 
 type FSHelper interface {
 	RemoveSrcFilesFromDst(srcDir, dstDir string) error
+	FileExists(root, fileRegex string) (bool, error)
 }
 
 type fsHelper struct {
@@ -49,3 +52,27 @@ func (fh *fsHelper) RemoveSrcFilesFromDst(srcDir, dstDir string) error {
 	}
 	return nil
 }
+
+func (fh *fsHelper) FileExists(root, fileRegex string) (bool, error) {
+	regex, err := regexp.Compile(fileRegex)
+	if err != nil {
+		return false, fmt.Errorf("failed to compile regex %s: %v", fileRegex, err)
+	}
+
+	found := false
+	// Walk through the directory
+	err = filepath.WalkDir(root, func(path string, d fs.DirEntry, err error) error {
+		if err != nil {
+			return err
+		}
+
+		// Match file names against the regex
+		if !d.IsDir() && regex.MatchString(d.Name()) {
+			found = true
+			return fs.SkipAll
+		}
+		return nil
+	})
+
+	return found, err
+}

internal/utils/filesystem_helper_test.go

@@ -14,6 +14,7 @@ var _ = Describe("RemoveSrcFilesFromDst", func() {
 		// source
 		err := os.MkdirAll("./srcDir/level1", 0750)
 		Expect(err).NotTo(HaveOccurred())
+		defer os.RemoveAll("./srcDir")
 		err = os.MkdirAll("./srcDir/level2", 0750)
 		Expect(err).NotTo(HaveOccurred())
 		err = os.MkdirAll("./srcDir/level4", 0750)
@@ -25,6 +26,7 @@ var _ = Describe("RemoveSrcFilesFromDst", func() {
 		// destination
 		err = os.MkdirAll("./dstDir/level1", 0750)
 		Expect(err).NotTo(HaveOccurred())
+		defer os.RemoveAll("./dstDir")
 		err = os.MkdirAll("./dstDir/level2", 0750)
 		Expect(err).NotTo(HaveOccurred())
 		err = os.MkdirAll("./dstDir/level3", 0750)
@@ -42,9 +44,45 @@ var _ = Describe("RemoveSrcFilesFromDst", func() {
 		verifyFileNotExists("./dstDir/level2/testfile2")
 
 		verifyFileExists("./dstDir/level3/testfile3")
+	})
+})
 
-		defer os.RemoveAll("./dstDir")
-		defer os.RemoveAll("./srcDir")
+var _ = Describe("FileExists", func() {
+	It("test files", func() {
+		err := os.MkdirAll("./testDir/level_1_0", 0750)
+		Expect(err).NotTo(HaveOccurred())
+		defer os.RemoveAll("./testDir")
+		err = os.MkdirAll("./testDir/level_1_1", 0750)
+		Expect(err).NotTo(HaveOccurred())
+		err = os.MkdirAll("./testDir/level_2_0", 0750)
+		Expect(err).NotTo(HaveOccurred())
+		err = os.MkdirAll("./testDir/level_2_1", 0750)
+		Expect(err).NotTo(HaveOccurred())
+		createEmptyFile("./testDir/level_1_1/not_ko_file")
+		createEmptyFile("./testDir/level_2_1/module1.ko.kz")
+		createEmptyFile("./testDir/level_1_0/module2.ko")
+
+		helper := NewFSHelper(logr.Discard())
+
+		By("find existing file by full name")
+		exists, err := helper.FileExists("testDir", "module2.ko")
+		Expect(err).NotTo(HaveOccurred())
+		Expect(exists).To(BeTrue())
+
+		By("find existing file by regexp name")
+		exists, err = helper.FileExists("testDir", `.*\.ko*$`)
+		Expect(err).NotTo(HaveOccurred())
+		Expect(exists).To(BeTrue())
+
+		By("find existing file by regexp name, comparing prefix")
+		exists, err = helper.FileExists("testDir", `^module1.ko`)
+		Expect(err).NotTo(HaveOccurred())
+		Expect(exists).To(BeTrue())
+
+		By("find non-existing file by regexp name")
+		exists, err = helper.FileExists("testDir", `.*\.koz.*$`)
+		Expect(err).NotTo(HaveOccurred())
+		Expect(exists).To(BeFalse())
 	})
 })
 

internal/utils/mock_filesystem_helper.go

@@ -47,10 +47,26 @@ func (w *worker) LoadKmod(ctx context.Context, cfg *kmmv1beta1.ModuleConfig, fir
 
 	if inTreeModulesToRemove != nil {
 		w.logger.Info("Unloading in-tree modules", "names", inTreeModulesToRemove)
+		modulesToUnload := make([]string, 0, len(inTreeModulesToRemove))
+		for _, module := range inTreeModulesToRemove {
+			exists, err := w.fh.FileExists("/lib/modules", fmt.Sprintf("^%s.ko", module))
+			if err != nil {
+				w.logger.Info(utils.WarnString(fmt.Sprintf("failed to check if module file %s present on the host:", module)), "error", err)
+				continue
+			}
+			if !exists {
+				w.logger.Info("not trying to unload in-tree module, since its file is not present on the host", "module", module)
+				continue
+			}
+			w.logger.Info("adding module to the list of intree modules to be unloadded", "module", module)
+			modulesToUnload = append(modulesToUnload, module)
+		}
 
-		runArgs := append([]string{"-rv"}, inTreeModulesToRemove...)
-		if err := w.mr.Run(ctx, runArgs...); err != nil {
-			return fmt.Errorf("could not remove in-tree modules %s: %v", strings.Join(inTreeModulesToRemove, ""), err)
+		if len(modulesToUnload) > 0 {
+			runArgs := append([]string{"-rv"}, modulesToUnload...)
+			if err := w.mr.Run(ctx, runArgs...); err != nil {
+				return fmt.Errorf("could not remove in-tree modules %s: %v", strings.Join(modulesToUnload, ""), err)
+			}
 		}
 	}
 

internal/worker/worker.go

@@ -3,6 +3,7 @@ package worker
 import (
 	"context"
 	"errors"
+	"fmt"
 	"os"
 	"path/filepath"
 
@@ -15,6 +16,7 @@ import (
 
 var _ = Describe("worker_LoadKmod", func() {
 	var (
+		fh       *utils.MockFSHelper
 		mr       *MockModprobeRunner
 		w        Worker
 		imageDir string
@@ -23,8 +25,9 @@ var _ = Describe("worker_LoadKmod", func() {
 
 	BeforeEach(func() {
 		ctrl := gomock.NewController(GinkgoT())
+		fh = utils.NewMockFSHelper(ctrl)
 		mr = NewMockModprobeRunner(ctrl)
-		w = NewWorker(mr, nil, GinkgoLogr)
+		w = NewWorker(mr, fh, GinkgoLogr)
 
 		var err error
 		imageDir, err = os.MkdirTemp("", "imageDir")
@@ -66,8 +69,8 @@ var _ = Describe("worker_LoadKmod", func() {
 		)
 	})
 
-	It("should remove the in-tree module if configured", func() {
-		inTreeModulesToRemove := []string{"intree1", "intree2"}
+	It("should remove present-on-host in-tree module if configured", func() {
+		inTreeModulesToRemove := []string{"intree1", "intree2", "intree3", "intree4"}
 
 		cfg := v1beta1.ModuleConfig{
 			ContainerImage:        imageName,
@@ -79,7 +82,11 @@ var _ = Describe("worker_LoadKmod", func() {
 		}
 
 		gomock.InOrder(
-			mr.EXPECT().Run(ctx, "-rv", "intree1", "intree2"),
+			fh.EXPECT().FileExists("/lib/modules", "^intree1.ko").Return(true, nil),
+			fh.EXPECT().FileExists("/lib/modules", "^intree2.ko").Return(false, nil),
+			fh.EXPECT().FileExists("/lib/modules", "^intree3.ko").Return(true, nil),
+			fh.EXPECT().FileExists("/lib/modules", "^intree4.ko").Return(false, fmt.Errorf("some error")),
+			mr.EXPECT().Run(ctx, "-rv", "intree1", "intree3"),
 			mr.EXPECT().Run(ctx, "-vd", filepath.Join(sharedFilesDir, dirName), moduleName),
 		)
 
@@ -102,6 +109,7 @@ var _ = Describe("worker_LoadKmod", func() {
 		}
 
 		gomock.InOrder(
+			fh.EXPECT().FileExists("/lib/modules", "^intreeToRemove.ko").Return(true, nil),
 			mr.EXPECT().Run(ctx, "-rv", "intreeToRemove"),
 			mr.EXPECT().Run(ctx, "-vd", filepath.Join(sharedFilesDir, dirName), moduleName),
 		)