Fixing ValidateHardLink, closes #256 (#257)

Signed-off-by: Alexei Dodon <adodon@cisco.com>

pkg/storage/storage_fs.go

@@ -1273,18 +1273,18 @@ func Scrub(dir string, fix bool) error {
 
 // utility routines
 
-func CheckHardLink(srcFileName string, destFileName string) error {
+func ValidateHardLink(rootDir string) error {
-	return os.Link(srcFileName, destFileName)
+	if err := os.MkdirAll(rootDir, 0700); err != nil {
+		return err
 	}
 
-func ValidateHardLink(rootDir string) error {
 	err := ioutil.WriteFile(path.Join(rootDir, "hardlinkcheck.txt"), //nolint: gosec
 		[]byte("check whether hardlinks work on filesystem"), 0644)
 	if err != nil {
 		return err
 	}
 
-	err = CheckHardLink(path.Join(rootDir, "hardlinkcheck.txt"), path.Join(rootDir, "duphardlinkcheck.txt"))
+	err = os.Link(path.Join(rootDir, "hardlinkcheck.txt"), path.Join(rootDir, "duphardlinkcheck.txt"))
 	if err != nil {
 		// Remove hardlinkcheck.txt if hardlink fails
 		zerr := os.RemoveAll(path.Join(rootDir, "hardlinkcheck.txt"))

pkg/storage/storage_test.go

@@ -5,12 +5,14 @@ import (
 	_ "crypto/sha256"
 	"encoding/json"
 	"io/ioutil"
+	"math/rand"
 	"os"
 	"os/exec"
 	"path"
 	"strings"
 	"sync"
 	"testing"
+	"time"
 
 	"github.com/anuvu/zot/errors"
 	"github.com/anuvu/zot/pkg/log"
@@ -978,6 +980,39 @@ func TestNegativeCases(t *testing.T) {
 }
 
 func TestHardLink(t *testing.T) {
+	Convey("Test that ValidateHardLink creates rootDir if it does not exist", t, func() {
+		var randomDir string
+
+		rand.Seed(time.Now().UnixNano())
+		for {
+			randomLen := rand.Intn(100)
+			randomDir = "/tmp/" + randSeq(randomLen)
+
+			if _, err := os.Stat(randomDir); os.IsNotExist(err) {
+				break
+			}
+		}
+		defer os.RemoveAll(randomDir)
+
+		err := storage.ValidateHardLink(randomDir)
+		So(err, ShouldBeNil)
+	})
+	Convey("Test that ValidateHardLink returns error if rootDir is a file", t, func() {
+		dir, err := ioutil.TempDir("", "storage-hard-test")
+		if err != nil {
+			panic(err)
+		}
+		defer os.RemoveAll(dir)
+
+		filePath := path.Join(dir, "file.txt")
+		err = ioutil.WriteFile(filePath, []byte("some dummy file content"), 0644) //nolint: gosec
+		if err != nil {
+			panic(err)
+		}
+
+		err = storage.ValidateHardLink(filePath)
+		So(err, ShouldNotBeNil)
+	})
 	Convey("Test if filesystem supports hardlink", t, func() {
 		dir, err := ioutil.TempDir("", "storage-hard-test")
 		if err != nil {
@@ -998,7 +1033,7 @@ func TestHardLink(t *testing.T) {
 			panic(err)
 		}
 
-		err = storage.CheckHardLink(path.Join(dir, "hardtest.txt"), path.Join(dir, "duphardtest.txt"))
+		err = os.Link(path.Join(dir, "hardtest.txt"), path.Join(dir, "duphardtest.txt"))
 		So(err, ShouldNotBeNil)
 
 		err = os.Chmod(dir, 0644)
@@ -1062,3 +1097,14 @@ func TestStorageHandler(t *testing.T) {
 		So(is.RootDir(), ShouldEqual, firstRootDir)
 	})
 }
+
+func randSeq(n int) string {
+	var letters = []rune("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ")
+
+	b := make([]rune, n)
+	for i := range b {
+		b[i] = letters[rand.Intn(len(letters))]
+	}
+
+	return string(b)
+}