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Add '-L' option for cp

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Fixes #16555

Original docker `cp` always copy symbol link itself instead of target,
now we provide '-L' option to allow docker to follow symbol link to real
target.

Signed-off-by: Zhang Wei <zhangwei555@huawei.com>
This commit is contained in:
Zhang Wei 2015-10-01 15:56:39 +08:00
parent 5edb94d724
commit b4340e2b6c
3 changed files with 432 additions and 29 deletions
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3
archive/changes_test.go
View file

@ -63,6 +63,9 @@ func createSampleDir(t *testing.T, root string) {
{Regular, "dir4/file3-2", "file4-2\n", 0666},
{Symlink, "symlink1", "target1", 0666},
{Symlink, "symlink2", "target2", 0666},
{Symlink, "symlink3", root + "/file1", 0666},
{Symlink, "symlink4", root + "/symlink3", 0666},
{Symlink, "dirSymlink", root + "/dir1", 0740},
}
now := time.Now()

101
archive/copy.go
View file

@ -135,30 +135,17 @@ type CopyInfo struct {
// operation. The given path should be an absolute local path. A source path
// has all symlinks evaluated that appear before the last path separator ("/"
// on Unix). As it is to be a copy source, the path must exist.
func CopyInfoSourcePath(path string) (CopyInfo, error) {
// Split the given path into its Directory and Base components. We will
// evaluate symlinks in the directory component then append the base.
func CopyInfoSourcePath(path string, followLink bool) (CopyInfo, error) {
// normalize the file path and then evaluate the symbol link
// we will use the target file instead of the symbol link if
// followLink is set
path = normalizePath(path)
dirPath, basePath := filepath.Split(path)
resolvedDirPath, err := filepath.EvalSymlinks(dirPath)
resolvedPath, rebaseName, err := ResolveHostSourcePath(path, followLink)
if err != nil {
return CopyInfo{}, err
}
// resolvedDirPath will have been cleaned (no trailing path separators) so
// we can manually join it with the base path element.
resolvedPath := resolvedDirPath + string(filepath.Separator) + basePath
var rebaseName string
if hasTrailingPathSeparator(path) && filepath.Base(path) != filepath.Base(resolvedPath) {
// In the case where the path had a trailing separator and a symlink
// evaluation has changed the last path component, we will need to
// rebase the name in the archive that is being copied to match the
// originally requested name.
rebaseName = filepath.Base(path)
}
stat, err := os.Lstat(resolvedPath)
if err != nil {
return CopyInfo{}, err
@ -279,7 +266,10 @@ func PrepareArchiveCopy(srcContent Reader, srcInfo, dstInfo CopyInfo) (dstDir st
// The destination exists as some type of file and the source content
// is also a file. The source content entry will have to be renamed to
// have a basename which matches the destination path's basename.
return dstDir, rebaseArchiveEntries(srcContent, srcBase, dstBase), nil
if len(srcInfo.RebaseName) != 0 {
srcBase = srcInfo.RebaseName
}
return dstDir, RebaseArchiveEntries(srcContent, srcBase, dstBase), nil
case srcInfo.IsDir:
// The destination does not exist and the source content is an archive
// of a directory. The archive should be extracted to the parent of
@ -287,7 +277,10 @@ func PrepareArchiveCopy(srcContent Reader, srcInfo, dstInfo CopyInfo) (dstDir st
// created as a result should take the name of the destination path.
// The source content entries will have to be renamed to have a
// basename which matches the destination path's basename.
return dstDir, rebaseArchiveEntries(srcContent, srcBase, dstBase), nil
if len(srcInfo.RebaseName) != 0 {
srcBase = srcInfo.RebaseName
}
return dstDir, RebaseArchiveEntries(srcContent, srcBase, dstBase), nil
case assertsDirectory(dstInfo.Path):
// The destination does not exist and is asserted to be created as a
// directory, but the source content is not a directory. This is an
@ -301,14 +294,17 @@ func PrepareArchiveCopy(srcContent Reader, srcInfo, dstInfo CopyInfo) (dstDir st
// to be created when the archive is extracted and the source content
// entry will have to be renamed to have a basename which matches the
// destination path's basename.
return dstDir, rebaseArchiveEntries(srcContent, srcBase, dstBase), nil
if len(srcInfo.RebaseName) != 0 {
srcBase = srcInfo.RebaseName
}
return dstDir, RebaseArchiveEntries(srcContent, srcBase, dstBase), nil
}
}
// rebaseArchiveEntries rewrites the given srcContent archive replacing
// RebaseArchiveEntries rewrites the given srcContent archive replacing
// an occurrence of oldBase with newBase at the beginning of entry names.
func rebaseArchiveEntries(srcContent Reader, oldBase, newBase string) Archive {
func RebaseArchiveEntries(srcContent Reader, oldBase, newBase string) Archive {
if oldBase == string(os.PathSeparator) {
// If oldBase specifies the root directory, use an empty string as
// oldBase instead so that newBase doesn't replace the path separator
@ -355,7 +351,7 @@ func rebaseArchiveEntries(srcContent Reader, oldBase, newBase string) Archive {
// CopyResource performs an archive copy from the given source path to the
// given destination path. The source path MUST exist and the destination
// path's parent directory must exist.
func CopyResource(srcPath, dstPath string) error {
func CopyResource(srcPath, dstPath string, followLink bool) error {
var (
srcInfo CopyInfo
err error
@ -369,7 +365,7 @@ func CopyResource(srcPath, dstPath string) error {
srcPath = PreserveTrailingDotOrSeparator(filepath.Clean(srcPath), srcPath)
dstPath = PreserveTrailingDotOrSeparator(filepath.Clean(dstPath), dstPath)
if srcInfo, err = CopyInfoSourcePath(srcPath); err != nil {
if srcInfo, err = CopyInfoSourcePath(srcPath, followLink); err != nil {
return err
}
@ -405,3 +401,58 @@ func CopyTo(content Reader, srcInfo CopyInfo, dstPath string) error {
return Untar(copyArchive, dstDir, options)
}
// ResolveHostSourcePath decides real path need to be copied with parameters such as
// whether to follow symbol link or not, if followLink is true, resolvedPath will return
// link target of any symbol link file, else it will only resolve symlink of directory
// but return symbol link file itself without resolving.
func ResolveHostSourcePath(path string, followLink bool) (resolvedPath, rebaseName string, err error) {
if followLink {
resolvedPath, err = filepath.EvalSymlinks(path)
if err != nil {
return
}
resolvedPath, rebaseName = GetRebaseName(path, resolvedPath)
} else {
dirPath, basePath := filepath.Split(path)
// if not follow symbol link, then resolve symbol link of parent dir
var resolvedDirPath string
resolvedDirPath, err = filepath.EvalSymlinks(dirPath)
if err != nil {
return
}
// resolvedDirPath will have been cleaned (no trailing path separators) so
// we can manually join it with the base path element.
resolvedPath = resolvedDirPath + string(filepath.Separator) + basePath
if hasTrailingPathSeparator(path) && filepath.Base(path) != filepath.Base(resolvedPath) {
rebaseName = filepath.Base(path)
}
}
return resolvedPath, rebaseName, nil
}
// GetRebaseName normalizes and compares path and resolvedPath,
// return completed resolved path and rebased file name
func GetRebaseName(path, resolvedPath string) (string, string) {
// linkTarget will have been cleaned (no trailing path separators and dot) so
// we can manually join it with them
var rebaseName string
if specifiesCurrentDir(path) && !specifiesCurrentDir(resolvedPath) {
resolvedPath += string(filepath.Separator) + "."
}
if hasTrailingPathSeparator(path) && !hasTrailingPathSeparator(resolvedPath) {
resolvedPath += string(filepath.Separator)
}
if filepath.Base(path) != filepath.Base(resolvedPath) {
// In the case where the path had a trailing separator and a symlink
// evaluation has changed the last path component, we will need to
// rebase the name in the archive that is being copied to match the
// originally requested name.
rebaseName = filepath.Base(path)
}
return resolvedPath, rebaseName
}

357
archive/copy_test.go
View file

@ -120,9 +120,15 @@ func logDirContents(t *testing.T, dirPath string) {
}
func testCopyHelper(t *testing.T, srcPath, dstPath string) (err error) {
t.Logf("copying from %q to %q", srcPath, dstPath)
t.Logf("copying from %q to %q (not follow symbol link)", srcPath, dstPath)
return CopyResource(srcPath, dstPath)
return CopyResource(srcPath, dstPath, false)
}
func testCopyHelperFSym(t *testing.T, srcPath, dstPath string) (err error) {
t.Logf("copying from %q to %q (follow symbol link)", srcPath, dstPath)
return CopyResource(srcPath, dstPath, true)
}
// Basic assumptions about SRC and DST:
@ -138,7 +144,7 @@ func TestCopyErrSrcNotExists(t *testing.T) {
tmpDirA, tmpDirB := getTestTempDirs(t)
defer removeAllPaths(tmpDirA, tmpDirB)
if _, err := CopyInfoSourcePath(filepath.Join(tmpDirA, "file1")); !os.IsNotExist(err) {
if _, err := CopyInfoSourcePath(filepath.Join(tmpDirA, "file1"), false); !os.IsNotExist(err) {
t.Fatalf("expected IsNotExist error, but got %T: %s", err, err)
}
}
@ -152,7 +158,7 @@ func TestCopyErrSrcNotDir(t *testing.T) {
// Load A with some sample files and directories.
createSampleDir(t, tmpDirA)
if _, err := CopyInfoSourcePath(joinTrailingSep(tmpDirA, "file1")); !isNotDir(err) {
if _, err := CopyInfoSourcePath(joinTrailingSep(tmpDirA, "file1"), false); !isNotDir(err) {
t.Fatalf("expected IsNotDir error, but got %T: %s", err, err)
}
}
@ -286,6 +292,27 @@ func TestCopyCaseA(t *testing.T) {
if err = fileContentsEqual(t, srcPath, dstPath); err != nil {
t.Fatal(err)
}
os.Remove(dstPath)
symlinkPath := filepath.Join(tmpDirA, "symlink3")
symlinkPath1 := filepath.Join(tmpDirA, "symlink4")
linkTarget := filepath.Join(tmpDirA, "file1")
if err = testCopyHelperFSym(t, symlinkPath, dstPath); err != nil {
t.Fatalf("unexpected error %T: %s", err, err)
}
if err = fileContentsEqual(t, linkTarget, dstPath); err != nil {
t.Fatal(err)
}
os.Remove(dstPath)
if err = testCopyHelperFSym(t, symlinkPath1, dstPath); err != nil {
t.Fatalf("unexpected error %T: %s", err, err)
}
if err = fileContentsEqual(t, linkTarget, dstPath); err != nil {
t.Fatal(err)
}
}
// B. SRC specifies a file and DST (with trailing path separator) doesn't
@ -310,6 +337,16 @@ func TestCopyCaseB(t *testing.T) {
if err != ErrDirNotExists {
t.Fatalf("expected ErrDirNotExists error, but got %T: %s", err, err)
}
symlinkPath := filepath.Join(tmpDirA, "symlink3")
if err = testCopyHelperFSym(t, symlinkPath, dstDir); err == nil {
t.Fatal("expected ErrDirNotExists error, but got nil instead")
}
if err != ErrDirNotExists {
t.Fatalf("expected ErrDirNotExists error, but got %T: %s", err, err)
}
}
// C. SRC specifies a file and DST exists as a file. This should overwrite
@ -341,6 +378,44 @@ func TestCopyCaseC(t *testing.T) {
}
}
// C. Symbol link following version:
// SRC specifies a file and DST exists as a file. This should overwrite
// the file at DST with the contents of the source file.
func TestCopyCaseCFSym(t *testing.T) {
tmpDirA, tmpDirB := getTestTempDirs(t)
defer removeAllPaths(tmpDirA, tmpDirB)
// Load A and B with some sample files and directories.
createSampleDir(t, tmpDirA)
createSampleDir(t, tmpDirB)
symlinkPathBad := filepath.Join(tmpDirA, "symlink1")
symlinkPath := filepath.Join(tmpDirA, "symlink3")
linkTarget := filepath.Join(tmpDirA, "file1")
dstPath := filepath.Join(tmpDirB, "file2")
var err error
// first to test broken link
if err = testCopyHelperFSym(t, symlinkPathBad, dstPath); err == nil {
t.Fatalf("unexpected error %T: %s", err, err)
}
// test symbol link -> symbol link -> target
// Ensure they start out different.
if err = fileContentsEqual(t, linkTarget, dstPath); err == nil {
t.Fatal("expected different file contents")
}
if err = testCopyHelperFSym(t, symlinkPath, dstPath); err != nil {
t.Fatalf("unexpected error %T: %s", err, err)
}
if err = fileContentsEqual(t, linkTarget, dstPath); err != nil {
t.Fatal(err)
}
}
// D. SRC specifies a file and DST exists as a directory. This should place
// a copy of the source file inside it using the basename from SRC. Ensure
// this works whether DST has a trailing path separator or not.
@ -392,6 +467,59 @@ func TestCopyCaseD(t *testing.T) {
}
}
// D. Symbol link following version:
// SRC specifies a file and DST exists as a directory. This should place
// a copy of the source file inside it using the basename from SRC. Ensure
// this works whether DST has a trailing path separator or not.
func TestCopyCaseDFSym(t *testing.T) {
tmpDirA, tmpDirB := getTestTempDirs(t)
defer removeAllPaths(tmpDirA, tmpDirB)
// Load A and B with some sample files and directories.
createSampleDir(t, tmpDirA)
createSampleDir(t, tmpDirB)
srcPath := filepath.Join(tmpDirA, "symlink4")
linkTarget := filepath.Join(tmpDirA, "file1")
dstDir := filepath.Join(tmpDirB, "dir1")
dstPath := filepath.Join(dstDir, "symlink4")
var err error
// Ensure that dstPath doesn't exist.
if _, err = os.Stat(dstPath); !os.IsNotExist(err) {
t.Fatalf("did not expect dstPath %q to exist", dstPath)
}
if err = testCopyHelperFSym(t, srcPath, dstDir); err != nil {
t.Fatalf("unexpected error %T: %s", err, err)
}
if err = fileContentsEqual(t, linkTarget, dstPath); err != nil {
t.Fatal(err)
}
// Now try again but using a trailing path separator for dstDir.
if err = os.RemoveAll(dstDir); err != nil {
t.Fatalf("unable to remove dstDir: %s", err)
}
if err = os.MkdirAll(dstDir, os.FileMode(0755)); err != nil {
t.Fatalf("unable to make dstDir: %s", err)
}
dstDir = joinTrailingSep(tmpDirB, "dir1")
if err = testCopyHelperFSym(t, srcPath, dstDir); err != nil {
t.Fatalf("unexpected error %T: %s", err, err)
}
if err = fileContentsEqual(t, linkTarget, dstPath); err != nil {
t.Fatal(err)
}
}
// E. SRC specifies a directory and DST does not exist. This should create a
// directory at DST and copy the contents of the SRC directory into the DST
// directory. Ensure this works whether DST has a trailing path separator or
@ -436,6 +564,52 @@ func TestCopyCaseE(t *testing.T) {
}
}
// E. Symbol link following version:
// SRC specifies a directory and DST does not exist. This should create a
// directory at DST and copy the contents of the SRC directory into the DST
// directory. Ensure this works whether DST has a trailing path separator or
// not.
func TestCopyCaseEFSym(t *testing.T) {
tmpDirA, tmpDirB := getTestTempDirs(t)
defer removeAllPaths(tmpDirA, tmpDirB)
// Load A with some sample files and directories.
createSampleDir(t, tmpDirA)
srcDir := filepath.Join(tmpDirA, "dirSymlink")
linkTarget := filepath.Join(tmpDirA, "dir1")
dstDir := filepath.Join(tmpDirB, "testDir")
var err error
if err = testCopyHelperFSym(t, srcDir, dstDir); err != nil {
t.Fatalf("unexpected error %T: %s", err, err)
}
if err = dirContentsEqual(t, dstDir, linkTarget); err != nil {
t.Log("dir contents not equal")
logDirContents(t, tmpDirA)
logDirContents(t, tmpDirB)
t.Fatal(err)
}
// Now try again but using a trailing path separator for dstDir.
if err = os.RemoveAll(dstDir); err != nil {
t.Fatalf("unable to remove dstDir: %s", err)
}
dstDir = joinTrailingSep(tmpDirB, "testDir")
if err = testCopyHelperFSym(t, srcDir, dstDir); err != nil {
t.Fatalf("unexpected error %T: %s", err, err)
}
if err = dirContentsEqual(t, dstDir, linkTarget); err != nil {
t.Fatal(err)
}
}
// F. SRC specifies a directory and DST exists as a file. This should cause an
// error as it is not possible to overwrite a file with a directory.
func TestCopyCaseF(t *testing.T) {
@ -447,6 +621,7 @@ func TestCopyCaseF(t *testing.T) {
createSampleDir(t, tmpDirB)
srcDir := filepath.Join(tmpDirA, "dir1")
symSrcDir := filepath.Join(tmpDirA, "dirSymlink")
dstFile := filepath.Join(tmpDirB, "file1")
var err error
@ -458,6 +633,15 @@ func TestCopyCaseF(t *testing.T) {
if err != ErrCannotCopyDir {
t.Fatalf("expected ErrCannotCopyDir error, but got %T: %s", err, err)
}
// now test with symbol link
if err = testCopyHelperFSym(t, symSrcDir, dstFile); err == nil {
t.Fatal("expected ErrCannotCopyDir error, but got nil instead")
}
if err != ErrCannotCopyDir {
t.Fatalf("expected ErrCannotCopyDir error, but got %T: %s", err, err)
}
}
// G. SRC specifies a directory and DST exists as a directory. This should copy
@ -506,6 +690,54 @@ func TestCopyCaseG(t *testing.T) {
}
}
// G. Symbol link version:
// SRC specifies a directory and DST exists as a directory. This should copy
// the SRC directory and all its contents to the DST directory. Ensure this
// works whether DST has a trailing path separator or not.
func TestCopyCaseGFSym(t *testing.T) {
tmpDirA, tmpDirB := getTestTempDirs(t)
defer removeAllPaths(tmpDirA, tmpDirB)
// Load A and B with some sample files and directories.
createSampleDir(t, tmpDirA)
createSampleDir(t, tmpDirB)
srcDir := filepath.Join(tmpDirA, "dirSymlink")
linkTarget := filepath.Join(tmpDirA, "dir1")
dstDir := filepath.Join(tmpDirB, "dir2")
resultDir := filepath.Join(dstDir, "dirSymlink")
var err error
if err = testCopyHelperFSym(t, srcDir, dstDir); err != nil {
t.Fatalf("unexpected error %T: %s", err, err)
}
if err = dirContentsEqual(t, resultDir, linkTarget); err != nil {
t.Fatal(err)
}
// Now try again but using a trailing path separator for dstDir.
if err = os.RemoveAll(dstDir); err != nil {
t.Fatalf("unable to remove dstDir: %s", err)
}
if err = os.MkdirAll(dstDir, os.FileMode(0755)); err != nil {
t.Fatalf("unable to make dstDir: %s", err)
}
dstDir = joinTrailingSep(tmpDirB, "dir2")
if err = testCopyHelperFSym(t, srcDir, dstDir); err != nil {
t.Fatalf("unexpected error %T: %s", err, err)
}
if err = dirContentsEqual(t, resultDir, linkTarget); err != nil {
t.Fatal(err)
}
}
// H. SRC specifies a directory's contents only and DST does not exist. This
// should create a directory at DST and copy the contents of the SRC
// directory (but not the directory itself) into the DST directory. Ensure
@ -553,6 +785,55 @@ func TestCopyCaseH(t *testing.T) {
}
}
// H. Symbol link following version:
// SRC specifies a directory's contents only and DST does not exist. This
// should create a directory at DST and copy the contents of the SRC
// directory (but not the directory itself) into the DST directory. Ensure
// this works whether DST has a trailing path separator or not.
func TestCopyCaseHFSym(t *testing.T) {
tmpDirA, tmpDirB := getTestTempDirs(t)
defer removeAllPaths(tmpDirA, tmpDirB)
// Load A with some sample files and directories.
createSampleDir(t, tmpDirA)
srcDir := joinTrailingSep(tmpDirA, "dirSymlink") + "."
linkTarget := filepath.Join(tmpDirA, "dir1")
dstDir := filepath.Join(tmpDirB, "testDir")
var err error
if err = testCopyHelperFSym(t, srcDir, dstDir); err != nil {
t.Fatalf("unexpected error %T: %s", err, err)
}
if err = dirContentsEqual(t, dstDir, linkTarget); err != nil {
t.Log("dir contents not equal")
logDirContents(t, tmpDirA)
logDirContents(t, tmpDirB)
t.Fatal(err)
}
// Now try again but using a trailing path separator for dstDir.
if err = os.RemoveAll(dstDir); err != nil {
t.Fatalf("unable to remove dstDir: %s", err)
}
dstDir = joinTrailingSep(tmpDirB, "testDir")
if err = testCopyHelperFSym(t, srcDir, dstDir); err != nil {
t.Fatalf("unexpected error %T: %s", err, err)
}
if err = dirContentsEqual(t, dstDir, linkTarget); err != nil {
t.Log("dir contents not equal")
logDirContents(t, tmpDirA)
logDirContents(t, tmpDirB)
t.Fatal(err)
}
}
// I. SRC specifies a directory's contents only and DST exists as a file. This
// should cause an error as it is not possible to overwrite a file with a
// directory.
@ -565,6 +846,7 @@ func TestCopyCaseI(t *testing.T) {
createSampleDir(t, tmpDirB)
srcDir := joinTrailingSep(tmpDirA, "dir1") + "."
symSrcDir := filepath.Join(tmpDirB, "dirSymlink")
dstFile := filepath.Join(tmpDirB, "file1")
var err error
@ -576,6 +858,15 @@ func TestCopyCaseI(t *testing.T) {
if err != ErrCannotCopyDir {
t.Fatalf("expected ErrCannotCopyDir error, but got %T: %s", err, err)
}
// now try with symbol link of dir
if err = testCopyHelperFSym(t, symSrcDir, dstFile); err == nil {
t.Fatal("expected ErrCannotCopyDir error, but got nil instead")
}
if err != ErrCannotCopyDir {
t.Fatalf("expected ErrCannotCopyDir error, but got %T: %s", err, err)
}
}
// J. SRC specifies a directory's contents only and DST exists as a directory.
@ -595,6 +886,11 @@ func TestCopyCaseJ(t *testing.T) {
var err error
// first to create an empty dir
if err = os.MkdirAll(dstDir, os.FileMode(0755)); err != nil {
t.Fatalf("unable to make dstDir: %s", err)
}
if err = testCopyHelper(t, srcDir, dstDir); err != nil {
t.Fatalf("unexpected error %T: %s", err, err)
}
@ -623,3 +919,56 @@ func TestCopyCaseJ(t *testing.T) {
t.Fatal(err)
}
}
// J. Symbol link following version:
// SRC specifies a directory's contents only and DST exists as a directory.
// This should copy the contents of the SRC directory (but not the directory
// itself) into the DST directory. Ensure this works whether DST has a
// trailing path separator or not.
func TestCopyCaseJFSym(t *testing.T) {
tmpDirA, tmpDirB := getTestTempDirs(t)
defer removeAllPaths(tmpDirA, tmpDirB)
// Load A and B with some sample files and directories.
createSampleDir(t, tmpDirA)
createSampleDir(t, tmpDirB)
srcDir := joinTrailingSep(tmpDirA, "dirSymlink") + "."
linkTarget := filepath.Join(tmpDirA, "dir1")
dstDir := filepath.Join(tmpDirB, "dir5")
var err error
// first to create an empty dir
if err = os.MkdirAll(dstDir, os.FileMode(0755)); err != nil {
t.Fatalf("unable to make dstDir: %s", err)
}
if err = testCopyHelperFSym(t, srcDir, dstDir); err != nil {
t.Fatalf("unexpected error %T: %s", err, err)
}
if err = dirContentsEqual(t, dstDir, linkTarget); err != nil {
t.Fatal(err)
}
// Now try again but using a trailing path separator for dstDir.
if err = os.RemoveAll(dstDir); err != nil {
t.Fatalf("unable to remove dstDir: %s", err)
}
if err = os.MkdirAll(dstDir, os.FileMode(0755)); err != nil {
t.Fatalf("unable to make dstDir: %s", err)
}
dstDir = joinTrailingSep(tmpDirB, "dir5")
if err = testCopyHelperFSym(t, srcDir, dstDir); err != nil {
t.Fatalf("unexpected error %T: %s", err, err)
}
if err = dirContentsEqual(t, dstDir, linkTarget); err != nil {
t.Fatal(err)
}
}