Adding upstream version 1.21.8.upstream/1.21.8

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1467 insertions, 0 deletions

diff --git a/src/os/os_windows_test.go b/src/os/os_windows_test.go
new file mode 100644
index 0000000..d6aab18
--- /dev/null
+++ b/src/os/os_windows_test.go
@@ -0,0 +1,1467 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package os_test
+
+import (
+	"errors"
+	"fmt"
+	"internal/poll"
+	"internal/syscall/windows"
+	"internal/syscall/windows/registry"
+	"internal/testenv"
+	"io"
+	"io/fs"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"reflect"
+	"runtime"
+	"slices"
+	"sort"
+	"strings"
+	"syscall"
+	"testing"
+	"unicode/utf16"
+	"unsafe"
+)
+
+// For TestRawConnReadWrite.
+type syscallDescriptor = syscall.Handle
+
+// chdir changes the current working directory to the named directory,
+// and then restore the original working directory at the end of the test.
+func chdir(t *testing.T, dir string) {
+	olddir, err := os.Getwd()
+	if err != nil {
+		t.Fatalf("chdir: %v", err)
+	}
+	if err := os.Chdir(dir); err != nil {
+		t.Fatalf("chdir %s: %v", dir, err)
+	}
+
+	t.Cleanup(func() {
+		if err := os.Chdir(olddir); err != nil {
+			t.Errorf("chdir to original working directory %s: %v", olddir, err)
+			os.Exit(1)
+		}
+	})
+}
+
+func TestSameWindowsFile(t *testing.T) {
+	temp := t.TempDir()
+	chdir(t, temp)
+
+	f, err := os.Create("a")
+	if err != nil {
+		t.Fatal(err)
+	}
+	f.Close()
+
+	ia1, err := os.Stat("a")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	path, err := filepath.Abs("a")
+	if err != nil {
+		t.Fatal(err)
+	}
+	ia2, err := os.Stat(path)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !os.SameFile(ia1, ia2) {
+		t.Errorf("files should be same")
+	}
+
+	p := filepath.VolumeName(path) + filepath.Base(path)
+	if err != nil {
+		t.Fatal(err)
+	}
+	ia3, err := os.Stat(p)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !os.SameFile(ia1, ia3) {
+		t.Errorf("files should be same")
+	}
+}
+
+type dirLinkTest struct {
+	name    string
+	mklink  func(link, target string) error
+	issueNo int // correspondent issue number (for broken tests)
+}
+
+func testDirLinks(t *testing.T, tests []dirLinkTest) {
+	tmpdir := t.TempDir()
+	chdir(t, tmpdir)
+
+	dir := filepath.Join(tmpdir, "dir")
+	err := os.Mkdir(dir, 0777)
+	if err != nil {
+		t.Fatal(err)
+	}
+	fi, err := os.Stat(dir)
+	if err != nil {
+		t.Fatal(err)
+	}
+	err = os.WriteFile(filepath.Join(dir, "abc"), []byte("abc"), 0644)
+	if err != nil {
+		t.Fatal(err)
+	}
+	for _, test := range tests {
+		link := filepath.Join(tmpdir, test.name+"_link")
+		err := test.mklink(link, dir)
+		if err != nil {
+			t.Errorf("creating link for %q test failed: %v", test.name, err)
+			continue
+		}
+
+		data, err := os.ReadFile(filepath.Join(link, "abc"))
+		if err != nil {
+			t.Errorf("failed to read abc file: %v", err)
+			continue
+		}
+		if string(data) != "abc" {
+			t.Errorf(`abc file is expected to have "abc" in it, but has %v`, data)
+			continue
+		}
+
+		if test.issueNo > 0 {
+			t.Logf("skipping broken %q test: see issue %d", test.name, test.issueNo)
+			continue
+		}
+
+		fi1, err := os.Stat(link)
+		if err != nil {
+			t.Errorf("failed to stat link %v: %v", link, err)
+			continue
+		}
+		if !fi1.IsDir() {
+			t.Errorf("%q should be a directory", link)
+			continue
+		}
+		if fi1.Name() != filepath.Base(link) {
+			t.Errorf("Stat(%q).Name() = %q, want %q", link, fi1.Name(), filepath.Base(link))
+			continue
+		}
+		if !os.SameFile(fi, fi1) {
+			t.Errorf("%q should point to %q", link, dir)
+			continue
+		}
+
+		fi2, err := os.Lstat(link)
+		if err != nil {
+			t.Errorf("failed to lstat link %v: %v", link, err)
+			continue
+		}
+		if m := fi2.Mode(); m&fs.ModeSymlink == 0 {
+			t.Errorf("%q should be a link, but is not (mode=0x%x)", link, uint32(m))
+			continue
+		}
+		if m := fi2.Mode(); m&fs.ModeDir != 0 {
+			t.Errorf("%q should be a link, not a directory (mode=0x%x)", link, uint32(m))
+			continue
+		}
+	}
+}
+
+// reparseData is used to build reparse buffer data required for tests.
+type reparseData struct {
+	substituteName namePosition
+	printName      namePosition
+	pathBuf        []uint16
+}
+
+type namePosition struct {
+	offset uint16
+	length uint16
+}
+
+func (rd *reparseData) addUTF16s(s []uint16) (offset uint16) {
+	off := len(rd.pathBuf) * 2
+	rd.pathBuf = append(rd.pathBuf, s...)
+	return uint16(off)
+}
+
+func (rd *reparseData) addString(s string) (offset, length uint16) {
+	p := syscall.StringToUTF16(s)
+	return rd.addUTF16s(p), uint16(len(p)-1) * 2 // do not include terminating NUL in the length (as per PrintNameLength and SubstituteNameLength documentation)
+}
+
+func (rd *reparseData) addSubstituteName(name string) {
+	rd.substituteName.offset, rd.substituteName.length = rd.addString(name)
+}
+
+func (rd *reparseData) addPrintName(name string) {
+	rd.printName.offset, rd.printName.length = rd.addString(name)
+}
+
+func (rd *reparseData) addStringNoNUL(s string) (offset, length uint16) {
+	p := syscall.StringToUTF16(s)
+	p = p[:len(p)-1]
+	return rd.addUTF16s(p), uint16(len(p)) * 2
+}
+
+func (rd *reparseData) addSubstituteNameNoNUL(name string) {
+	rd.substituteName.offset, rd.substituteName.length = rd.addStringNoNUL(name)
+}
+
+func (rd *reparseData) addPrintNameNoNUL(name string) {
+	rd.printName.offset, rd.printName.length = rd.addStringNoNUL(name)
+}
+
+// pathBuffeLen returns length of rd pathBuf in bytes.
+func (rd *reparseData) pathBuffeLen() uint16 {
+	return uint16(len(rd.pathBuf)) * 2
+}
+
+// Windows REPARSE_DATA_BUFFER contains union member, and cannot be
+// translated into Go directly. _REPARSE_DATA_BUFFER type is to help
+// construct alternative versions of Windows REPARSE_DATA_BUFFER with
+// union part of SymbolicLinkReparseBuffer or MountPointReparseBuffer type.
+type _REPARSE_DATA_BUFFER struct {
+	header windows.REPARSE_DATA_BUFFER_HEADER
+	detail [syscall.MAXIMUM_REPARSE_DATA_BUFFER_SIZE]byte
+}
+
+func createDirLink(link string, rdb *_REPARSE_DATA_BUFFER) error {
+	err := os.Mkdir(link, 0777)
+	if err != nil {
+		return err
+	}
+
+	linkp := syscall.StringToUTF16(link)
+	fd, err := syscall.CreateFile(&linkp[0], syscall.GENERIC_WRITE, 0, nil, syscall.OPEN_EXISTING,
+		syscall.FILE_FLAG_OPEN_REPARSE_POINT|syscall.FILE_FLAG_BACKUP_SEMANTICS, 0)
+	if err != nil {
+		return err
+	}
+	defer syscall.CloseHandle(fd)
+
+	buflen := uint32(rdb.header.ReparseDataLength) + uint32(unsafe.Sizeof(rdb.header))
+	var bytesReturned uint32
+	return syscall.DeviceIoControl(fd, windows.FSCTL_SET_REPARSE_POINT,
+		(*byte)(unsafe.Pointer(&rdb.header)), buflen, nil, 0, &bytesReturned, nil)
+}
+
+func createMountPoint(link string, target *reparseData) error {
+	var buf *windows.MountPointReparseBuffer
+	buflen := uint16(unsafe.Offsetof(buf.PathBuffer)) + target.pathBuffeLen() // see ReparseDataLength documentation
+	byteblob := make([]byte, buflen)
+	buf = (*windows.MountPointReparseBuffer)(unsafe.Pointer(&byteblob[0]))
+	buf.SubstituteNameOffset = target.substituteName.offset
+	buf.SubstituteNameLength = target.substituteName.length
+	buf.PrintNameOffset = target.printName.offset
+	buf.PrintNameLength = target.printName.length
+	pbuflen := len(target.pathBuf)
+	copy((*[2048]uint16)(unsafe.Pointer(&buf.PathBuffer[0]))[:pbuflen:pbuflen], target.pathBuf)
+
+	var rdb _REPARSE_DATA_BUFFER
+	rdb.header.ReparseTag = windows.IO_REPARSE_TAG_MOUNT_POINT
+	rdb.header.ReparseDataLength = buflen
+	copy(rdb.detail[:], byteblob)
+
+	return createDirLink(link, &rdb)
+}
+
+func TestDirectoryJunction(t *testing.T) {
+	var tests = []dirLinkTest{
+		{
+			// Create link similar to what mklink does, by inserting \??\ at the front of absolute target.
+			name: "standard",
+			mklink: func(link, target string) error {
+				var t reparseData
+				t.addSubstituteName(`\??\` + target)
+				t.addPrintName(target)
+				return createMountPoint(link, &t)
+			},
+		},
+		{
+			// Do as junction utility https://technet.microsoft.com/en-au/sysinternals/bb896768.aspx does - set PrintNameLength to 0.
+			name: "have_blank_print_name",
+			mklink: func(link, target string) error {
+				var t reparseData
+				t.addSubstituteName(`\??\` + target)
+				t.addPrintName("")
+				return createMountPoint(link, &t)
+			},
+		},
+	}
+	output, _ := testenv.Command(t, "cmd", "/c", "mklink", "/?").Output()
+	mklinkSupportsJunctionLinks := strings.Contains(string(output), " /J ")
+	if mklinkSupportsJunctionLinks {
+		tests = append(tests,
+			dirLinkTest{
+				name: "use_mklink_cmd",
+				mklink: func(link, target string) error {
+					output, err := testenv.Command(t, "cmd", "/c", "mklink", "/J", link, target).CombinedOutput()
+					if err != nil {
+						t.Errorf("failed to run mklink %v %v: %v %q", link, target, err, output)
+					}
+					return nil
+				},
+			},
+		)
+	} else {
+		t.Log(`skipping "use_mklink_cmd" test, mklink does not supports directory junctions`)
+	}
+	testDirLinks(t, tests)
+}
+
+func enableCurrentThreadPrivilege(privilegeName string) error {
+	ct, err := windows.GetCurrentThread()
+	if err != nil {
+		return err
+	}
+	var t syscall.Token
+	err = windows.OpenThreadToken(ct, syscall.TOKEN_QUERY|windows.TOKEN_ADJUST_PRIVILEGES, false, &t)
+	if err != nil {
+		return err
+	}
+	defer syscall.CloseHandle(syscall.Handle(t))
+
+	var tp windows.TOKEN_PRIVILEGES
+
+	privStr, err := syscall.UTF16PtrFromString(privilegeName)
+	if err != nil {
+		return err
+	}
+	err = windows.LookupPrivilegeValue(nil, privStr, &tp.Privileges[0].Luid)
+	if err != nil {
+		return err
+	}
+	tp.PrivilegeCount = 1
+	tp.Privileges[0].Attributes = windows.SE_PRIVILEGE_ENABLED
+	return windows.AdjustTokenPrivileges(t, false, &tp, 0, nil, nil)
+}
+
+func createSymbolicLink(link string, target *reparseData, isrelative bool) error {
+	var buf *windows.SymbolicLinkReparseBuffer
+	buflen := uint16(unsafe.Offsetof(buf.PathBuffer)) + target.pathBuffeLen() // see ReparseDataLength documentation
+	byteblob := make([]byte, buflen)
+	buf = (*windows.SymbolicLinkReparseBuffer)(unsafe.Pointer(&byteblob[0]))
+	buf.SubstituteNameOffset = target.substituteName.offset
+	buf.SubstituteNameLength = target.substituteName.length
+	buf.PrintNameOffset = target.printName.offset
+	buf.PrintNameLength = target.printName.length
+	if isrelative {
+		buf.Flags = windows.SYMLINK_FLAG_RELATIVE
+	}
+	pbuflen := len(target.pathBuf)
+	copy((*[2048]uint16)(unsafe.Pointer(&buf.PathBuffer[0]))[:pbuflen:pbuflen], target.pathBuf)
+
+	var rdb _REPARSE_DATA_BUFFER
+	rdb.header.ReparseTag = syscall.IO_REPARSE_TAG_SYMLINK
+	rdb.header.ReparseDataLength = buflen
+	copy(rdb.detail[:], byteblob)
+
+	return createDirLink(link, &rdb)
+}
+
+func TestDirectorySymbolicLink(t *testing.T) {
+	var tests []dirLinkTest
+	output, _ := testenv.Command(t, "cmd", "/c", "mklink", "/?").Output()
+	mklinkSupportsDirectorySymbolicLinks := strings.Contains(string(output), " /D ")
+	if mklinkSupportsDirectorySymbolicLinks {
+		tests = append(tests,
+			dirLinkTest{
+				name: "use_mklink_cmd",
+				mklink: func(link, target string) error {
+					output, err := testenv.Command(t, "cmd", "/c", "mklink", "/D", link, target).CombinedOutput()
+					if err != nil {
+						t.Errorf("failed to run mklink %v %v: %v %q", link, target, err, output)
+					}
+					return nil
+				},
+			},
+		)
+	} else {
+		t.Log(`skipping "use_mklink_cmd" test, mklink does not supports directory symbolic links`)
+	}
+
+	// The rest of these test requires SeCreateSymbolicLinkPrivilege to be held.
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	err := windows.ImpersonateSelf(windows.SecurityImpersonation)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer windows.RevertToSelf()
+
+	err = enableCurrentThreadPrivilege("SeCreateSymbolicLinkPrivilege")
+	if err != nil {
+		t.Skipf(`skipping some tests, could not enable "SeCreateSymbolicLinkPrivilege": %v`, err)
+	}
+	tests = append(tests,
+		dirLinkTest{
+			name: "use_os_pkg",
+			mklink: func(link, target string) error {
+				return os.Symlink(target, link)
+			},
+		},
+		dirLinkTest{
+			// Create link similar to what mklink does, by inserting \??\ at the front of absolute target.
+			name: "standard",
+			mklink: func(link, target string) error {
+				var t reparseData
+				t.addPrintName(target)
+				t.addSubstituteName(`\??\` + target)
+				return createSymbolicLink(link, &t, false)
+			},
+		},
+		dirLinkTest{
+			name: "relative",
+			mklink: func(link, target string) error {
+				var t reparseData
+				t.addSubstituteNameNoNUL(filepath.Base(target))
+				t.addPrintNameNoNUL(filepath.Base(target))
+				return createSymbolicLink(link, &t, true)
+			},
+		},
+	)
+	testDirLinks(t, tests)
+}
+
+func TestNetworkSymbolicLink(t *testing.T) {
+	testenv.MustHaveSymlink(t)
+
+	const _NERR_ServerNotStarted = syscall.Errno(2114)
+
+	dir := t.TempDir()
+	chdir(t, dir)
+
+	shareName := "GoSymbolicLinkTestShare" // hope no conflictions
+	sharePath := filepath.Join(dir, shareName)
+	testDir := "TestDir"
+
+	err := os.MkdirAll(filepath.Join(sharePath, testDir), 0777)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	wShareName, err := syscall.UTF16PtrFromString(shareName)
+	if err != nil {
+		t.Fatal(err)
+	}
+	wSharePath, err := syscall.UTF16PtrFromString(sharePath)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	p := windows.SHARE_INFO_2{
+		Netname:     wShareName,
+		Type:        windows.STYPE_DISKTREE,
+		Remark:      nil,
+		Permissions: 0,
+		MaxUses:     1,
+		CurrentUses: 0,
+		Path:        wSharePath,
+		Passwd:      nil,
+	}
+
+	err = windows.NetShareAdd(nil, 2, (*byte)(unsafe.Pointer(&p)), nil)
+	if err != nil {
+		if err == syscall.ERROR_ACCESS_DENIED {
+			t.Skip("you don't have enough privileges to add network share")
+		}
+		if err == _NERR_ServerNotStarted {
+			t.Skip(_NERR_ServerNotStarted.Error())
+		}
+		t.Fatal(err)
+	}
+	defer func() {
+		err := windows.NetShareDel(nil, wShareName, 0)
+		if err != nil {
+			t.Fatal(err)
+		}
+	}()
+
+	UNCPath := `\\localhost\` + shareName + `\`
+
+	fi1, err := os.Stat(sharePath)
+	if err != nil {
+		t.Fatal(err)
+	}
+	fi2, err := os.Stat(UNCPath)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !os.SameFile(fi1, fi2) {
+		t.Fatalf("%q and %q should be the same directory, but not", sharePath, UNCPath)
+	}
+
+	target := filepath.Join(UNCPath, testDir)
+	link := "link"
+
+	err = os.Symlink(target, link)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.Remove(link)
+
+	got, err := os.Readlink(link)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got != target {
+		t.Errorf(`os.Readlink("%s"): got %v, want %v`, link, got, target)
+	}
+
+	got, err = filepath.EvalSymlinks(link)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got != target {
+		t.Errorf(`filepath.EvalSymlinks("%s"): got %v, want %v`, link, got, target)
+	}
+}
+
+func TestStartProcessAttr(t *testing.T) {
+	t.Parallel()
+
+	p, err := os.StartProcess(os.Getenv("COMSPEC"), []string{"/c", "cd"}, new(os.ProcAttr))
+	if err != nil {
+		return
+	}
+	defer p.Wait()
+	t.Fatalf("StartProcess expected to fail, but succeeded.")
+}
+
+func TestShareNotExistError(t *testing.T) {
+	if testing.Short() {
+		t.Skip("slow test that uses network; skipping")
+	}
+	t.Parallel()
+
+	_, err := os.Stat(`\\no_such_server\no_such_share\no_such_file`)
+	if err == nil {
+		t.Fatal("stat succeeded, but expected to fail")
+	}
+	if !os.IsNotExist(err) {
+		t.Fatalf("os.Stat failed with %q, but os.IsNotExist(err) is false", err)
+	}
+}
+
+func TestBadNetPathError(t *testing.T) {
+	const ERROR_BAD_NETPATH = syscall.Errno(53)
+	if !os.IsNotExist(ERROR_BAD_NETPATH) {
+		t.Fatal("os.IsNotExist(syscall.Errno(53)) is false, but want true")
+	}
+}
+
+func TestStatDir(t *testing.T) {
+	defer chtmpdir(t)()
+
+	f, err := os.Open(".")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer f.Close()
+
+	fi, err := f.Stat()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = os.Chdir("..")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	fi2, err := f.Stat()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if !os.SameFile(fi, fi2) {
+		t.Fatal("race condition occurred")
+	}
+}
+
+func TestOpenVolumeName(t *testing.T) {
+	tmpdir := t.TempDir()
+	chdir(t, tmpdir)
+
+	want := []string{"file1", "file2", "file3", "gopher.txt"}
+	sort.Strings(want)
+	for _, name := range want {
+		err := os.WriteFile(filepath.Join(tmpdir, name), nil, 0777)
+		if err != nil {
+			t.Fatal(err)
+		}
+	}
+
+	f, err := os.Open(filepath.VolumeName(tmpdir))
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer f.Close()
+
+	have, err := f.Readdirnames(-1)
+	if err != nil {
+		t.Fatal(err)
+	}
+	sort.Strings(have)
+
+	if strings.Join(want, "/") != strings.Join(have, "/") {
+		t.Fatalf("unexpected file list %q, want %q", have, want)
+	}
+}
+
+func TestDeleteReadOnly(t *testing.T) {
+	t.Parallel()
+
+	tmpdir := t.TempDir()
+	p := filepath.Join(tmpdir, "a")
+	// This sets FILE_ATTRIBUTE_READONLY.
+	f, err := os.OpenFile(p, os.O_CREATE, 0400)
+	if err != nil {
+		t.Fatal(err)
+	}
+	f.Close()
+
+	if err = os.Chmod(p, 0400); err != nil {
+		t.Fatal(err)
+	}
+	if err = os.Remove(p); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestReadStdin(t *testing.T) {
+	old := poll.ReadConsole
+	defer func() {
+		poll.ReadConsole = old
+	}()
+
+	p, err := syscall.GetCurrentProcess()
+	if err != nil {
+		t.Fatalf("Unable to get handle to current process: %v", err)
+	}
+	var stdinDuplicate syscall.Handle
+	err = syscall.DuplicateHandle(p, syscall.Handle(syscall.Stdin), p, &stdinDuplicate, 0, false, syscall.DUPLICATE_SAME_ACCESS)
+	if err != nil {
+		t.Fatalf("Unable to duplicate stdin: %v", err)
+	}
+	testConsole := os.NewConsoleFile(stdinDuplicate, "test")
+
+	var tests = []string{
+		"abc",
+		"äöü",
+		"\u3042",
+		"“hi”™",
+		"hello\x1aworld",
+		"\U0001F648\U0001F649\U0001F64A",
+	}
+
+	for _, consoleSize := range []int{1, 2, 3, 10, 16, 100, 1000} {
+		for _, readSize := range []int{1, 2, 3, 4, 5, 8, 10, 16, 20, 50, 100} {
+			for _, s := range tests {
+				t.Run(fmt.Sprintf("c%d/r%d/%s", consoleSize, readSize, s), func(t *testing.T) {
+					s16 := utf16.Encode([]rune(s))
+					poll.ReadConsole = func(h syscall.Handle, buf *uint16, toread uint32, read *uint32, inputControl *byte) error {
+						if inputControl != nil {
+							t.Fatalf("inputControl not nil")
+						}
+						n := int(toread)
+						if n > consoleSize {
+							n = consoleSize
+						}
+						n = copy((*[10000]uint16)(unsafe.Pointer(buf))[:n:n], s16)
+						s16 = s16[n:]
+						*read = uint32(n)
+						t.Logf("read %d -> %d", toread, *read)
+						return nil
+					}
+
+					var all []string
+					var buf []byte
+					chunk := make([]byte, readSize)
+					for {
+						n, err := testConsole.Read(chunk)
+						buf = append(buf, chunk[:n]...)
+						if err == io.EOF {
+							all = append(all, string(buf))
+							if len(all) >= 5 {
+								break
+							}
+							buf = buf[:0]
+						} else if err != nil {
+							t.Fatalf("reading %q: error: %v", s, err)
+						}
+						if len(buf) >= 2000 {
+							t.Fatalf("reading %q: stuck in loop: %q", s, buf)
+						}
+					}
+
+					want := strings.Split(s, "\x1a")
+					for len(want) < 5 {
+						want = append(want, "")
+					}
+					if !reflect.DeepEqual(all, want) {
+						t.Errorf("reading %q:\nhave %x\nwant %x", s, all, want)
+					}
+				})
+			}
+		}
+	}
+}
+
+func TestStatPagefile(t *testing.T) {
+	t.Parallel()
+
+	const path = `c:\pagefile.sys`
+	fi, err := os.Stat(path)
+	if err == nil {
+		if fi.Name() == "" {
+			t.Fatalf("Stat(%q).Name() is empty", path)
+		}
+		t.Logf("Stat(%q).Size() = %v", path, fi.Size())
+		return
+	}
+	if os.IsNotExist(err) {
+		t.Skip(`skipping because c:\pagefile.sys is not found`)
+	}
+	t.Fatal(err)
+}
+
+// syscallCommandLineToArgv calls syscall.CommandLineToArgv
+// and converts returned result into []string.
+func syscallCommandLineToArgv(cmd string) ([]string, error) {
+	var argc int32
+	argv, err := syscall.CommandLineToArgv(&syscall.StringToUTF16(cmd)[0], &argc)
+	if err != nil {
+		return nil, err
+	}
+	defer syscall.LocalFree(syscall.Handle(uintptr(unsafe.Pointer(argv))))
+
+	var args []string
+	for _, v := range (*argv)[:argc] {
+		args = append(args, syscall.UTF16ToString((*v)[:]))
+	}
+	return args, nil
+}
+
+// compareCommandLineToArgvWithSyscall ensures that
+// os.CommandLineToArgv(cmd) and syscall.CommandLineToArgv(cmd)
+// return the same result.
+func compareCommandLineToArgvWithSyscall(t *testing.T, cmd string) {
+	syscallArgs, err := syscallCommandLineToArgv(cmd)
+	if err != nil {
+		t.Fatal(err)
+	}
+	args := os.CommandLineToArgv(cmd)
+	if want, have := fmt.Sprintf("%q", syscallArgs), fmt.Sprintf("%q", args); want != have {
+		t.Errorf("testing os.commandLineToArgv(%q) failed: have %q want %q", cmd, args, syscallArgs)
+		return
+	}
+}
+
+func TestCmdArgs(t *testing.T) {
+	if testing.Short() {
+		t.Skipf("in short mode; skipping test that builds a binary")
+	}
+	t.Parallel()
+
+	tmpdir := t.TempDir()
+
+	const prog = `
+package main
+
+import (
+	"fmt"
+	"os"
+)
+
+func main() {
+	fmt.Printf("%q", os.Args)
+}
+`
+	src := filepath.Join(tmpdir, "main.go")
+	if err := os.WriteFile(src, []byte(prog), 0666); err != nil {
+		t.Fatal(err)
+	}
+
+	exe := filepath.Join(tmpdir, "main.exe")
+	cmd := testenv.Command(t, testenv.GoToolPath(t), "build", "-o", exe, src)
+	cmd.Dir = tmpdir
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		t.Fatalf("building main.exe failed: %v\n%s", err, out)
+	}
+
+	var cmds = []string{
+		``,
+		` a b c`,
+		` "`,
+		` ""`,
+		` """`,
+		` "" a`,
+		` "123"`,
+		` \"123\"`,
+		` \"123 456\"`,
+		` \\"`,
+		` \\\"`,
+		` \\\\\"`,
+		` \\\"x`,
+		` """"\""\\\"`,
+		` abc`,
+		` \\\\\""x"""y z`,
+		"\tb\t\"x\ty\"",
+		` "Брад" d e`,
+		// examples from https://msdn.microsoft.com/en-us/library/17w5ykft.aspx
+		` "abc" d e`,
+		` a\\b d"e f"g h`,
+		` a\\\"b c d`,
+		` a\\\\"b c" d e`,
+		// http://daviddeley.com/autohotkey/parameters/parameters.htm#WINARGV
+		// from 5.4  Examples
+		` CallMeIshmael`,
+		` "Call Me Ishmael"`,
+		` Cal"l Me I"shmael`,
+		` CallMe\"Ishmael`,
+		` "CallMe\"Ishmael"`,
+		` "Call Me Ishmael\\"`,
+		` "CallMe\\\"Ishmael"`,
+		` a\\\b`,
+		` "a\\\b"`,
+		// from 5.5  Some Common Tasks
+		` "\"Call Me Ishmael\""`,
+		` "C:\TEST A\\"`,
+		` "\"C:\TEST A\\\""`,
+		// from 5.6  The Microsoft Examples Explained
+		` "a b c"  d  e`,
+		` "ab\"c"  "\\"  d`,
+		` a\\\b d"e f"g h`,
+		` a\\\"b c d`,
+		` a\\\\"b c" d e`,
+		// from 5.7  Double Double Quote Examples (pre 2008)
+		` "a b c""`,
+		` """CallMeIshmael"""  b  c`,
+		` """Call Me Ishmael"""`,
+		` """"Call Me Ishmael"" b c`,
+	}
+	for _, cmd := range cmds {
+		compareCommandLineToArgvWithSyscall(t, "test"+cmd)
+		compareCommandLineToArgvWithSyscall(t, `"cmd line"`+cmd)
+		compareCommandLineToArgvWithSyscall(t, exe+cmd)
+
+		// test both syscall.EscapeArg and os.commandLineToArgv
+		args := os.CommandLineToArgv(exe + cmd)
+		out, err := testenv.Command(t, args[0], args[1:]...).CombinedOutput()
+		if err != nil {
+			t.Fatalf("running %q failed: %v\n%v", args, err, string(out))
+		}
+		if want, have := fmt.Sprintf("%q", args), string(out); want != have {
+			t.Errorf("wrong output of executing %q: have %q want %q", args, have, want)
+			continue
+		}
+	}
+}
+
+func findOneDriveDir() (string, error) {
+	// as per https://stackoverflow.com/questions/42519624/how-to-determine-location-of-onedrive-on-windows-7-and-8-in-c
+	const onedrivekey = `SOFTWARE\Microsoft\OneDrive`
+	k, err := registry.OpenKey(registry.CURRENT_USER, onedrivekey, registry.READ)
+	if err != nil {
+		return "", fmt.Errorf("OpenKey(%q) failed: %v", onedrivekey, err)
+	}
+	defer k.Close()
+
+	path, valtype, err := k.GetStringValue("UserFolder")
+	if err != nil {
+		return "", fmt.Errorf("reading UserFolder failed: %v", err)
+	}
+
+	if valtype == registry.EXPAND_SZ {
+		expanded, err := registry.ExpandString(path)
+		if err != nil {
+			return "", fmt.Errorf("expanding UserFolder failed: %v", err)
+		}
+		path = expanded
+	}
+
+	return path, nil
+}
+
+// TestOneDrive verifies that OneDrive folder is a directory and not a symlink.
+func TestOneDrive(t *testing.T) {
+	t.Parallel()
+
+	dir, err := findOneDriveDir()
+	if err != nil {
+		t.Skipf("Skipping, because we did not find OneDrive directory: %v", err)
+	}
+	testDirStats(t, dir)
+}
+
+func TestWindowsDevNullFile(t *testing.T) {
+	t.Parallel()
+
+	f1, err := os.Open("NUL")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer f1.Close()
+
+	fi1, err := f1.Stat()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	f2, err := os.Open("nul")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer f2.Close()
+
+	fi2, err := f2.Stat()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if !os.SameFile(fi1, fi2) {
+		t.Errorf(`"NUL" and "nul" are not the same file`)
+	}
+}
+
+func TestFileStatNUL(t *testing.T) {
+	t.Parallel()
+
+	f, err := os.Open("NUL")
+	if err != nil {
+		t.Fatal(err)
+	}
+	fi, err := f.Stat()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got, want := fi.Mode(), os.ModeDevice|os.ModeCharDevice|0666; got != want {
+		t.Errorf("Open(%q).Stat().Mode() = %v, want %v", "NUL", got, want)
+	}
+}
+
+func TestStatNUL(t *testing.T) {
+	t.Parallel()
+
+	fi, err := os.Stat("NUL")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got, want := fi.Mode(), os.ModeDevice|os.ModeCharDevice|0666; got != want {
+		t.Errorf("Stat(%q).Mode() = %v, want %v", "NUL", got, want)
+	}
+}
+
+// TestSymlinkCreation verifies that creating a symbolic link
+// works on Windows when developer mode is active.
+// This is supported starting Windows 10 (1703, v10.0.14972).
+func TestSymlinkCreation(t *testing.T) {
+	if !testenv.HasSymlink() && !isWindowsDeveloperModeActive() {
+		t.Skip("Windows developer mode is not active")
+	}
+	t.Parallel()
+
+	temp := t.TempDir()
+	dummyFile := filepath.Join(temp, "file")
+	if err := os.WriteFile(dummyFile, []byte(""), 0644); err != nil {
+		t.Fatal(err)
+	}
+
+	linkFile := filepath.Join(temp, "link")
+	if err := os.Symlink(dummyFile, linkFile); err != nil {
+		t.Fatal(err)
+	}
+}
+
+// isWindowsDeveloperModeActive checks whether or not the developer mode is active on Windows 10.
+// Returns false for prior Windows versions.
+// see https://docs.microsoft.com/en-us/windows/uwp/get-started/enable-your-device-for-development
+func isWindowsDeveloperModeActive() bool {
+	key, err := registry.OpenKey(registry.LOCAL_MACHINE, "SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\AppModelUnlock", registry.READ)
+	if err != nil {
+		return false
+	}
+
+	val, _, err := key.GetIntegerValue("AllowDevelopmentWithoutDevLicense")
+	if err != nil {
+		return false
+	}
+
+	return val != 0
+}
+
+// TestRootRelativeDirSymlink verifies that symlinks to paths relative to the
+// drive root (beginning with "\" but no volume name) are created with the
+// correct symlink type.
+// (See https://golang.org/issue/39183#issuecomment-632175728.)
+func TestRootRelativeDirSymlink(t *testing.T) {
+	testenv.MustHaveSymlink(t)
+	t.Parallel()
+
+	temp := t.TempDir()
+	dir := filepath.Join(temp, "dir")
+	if err := os.Mkdir(dir, 0755); err != nil {
+		t.Fatal(err)
+	}
+
+	volumeRelDir := strings.TrimPrefix(dir, filepath.VolumeName(dir)) // leaves leading backslash
+
+	link := filepath.Join(temp, "link")
+	err := os.Symlink(volumeRelDir, link)
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Logf("Symlink(%#q, %#q)", volumeRelDir, link)
+
+	f, err := os.Open(link)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer f.Close()
+	if fi, err := f.Stat(); err != nil {
+		t.Fatal(err)
+	} else if !fi.IsDir() {
+		t.Errorf("Open(%#q).Stat().IsDir() = false; want true", f.Name())
+	}
+}
+
+// TestWorkingDirectoryRelativeSymlink verifies that symlinks to paths relative
+// to the current working directory for the drive, such as "C:File.txt", are
+// correctly converted to absolute links of the correct symlink type (per
+// https://docs.microsoft.com/en-us/windows/win32/fileio/creating-symbolic-links).
+func TestWorkingDirectoryRelativeSymlink(t *testing.T) {
+	testenv.MustHaveSymlink(t)
+
+	// Construct a directory to be symlinked.
+	temp := t.TempDir()
+	if v := filepath.VolumeName(temp); len(v) < 2 || v[1] != ':' {
+		t.Skipf("Can't test relative symlinks: t.TempDir() (%#q) does not begin with a drive letter.", temp)
+	}
+
+	absDir := filepath.Join(temp, `dir\sub`)
+	if err := os.MkdirAll(absDir, 0755); err != nil {
+		t.Fatal(err)
+	}
+
+	// Change to the temporary directory and construct a
+	// working-directory-relative symlink.
+	oldwd, err := os.Getwd()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer func() {
+		if err := os.Chdir(oldwd); err != nil {
+			t.Fatal(err)
+		}
+	}()
+	if err := os.Chdir(temp); err != nil {
+		t.Fatal(err)
+	}
+	t.Logf("Chdir(%#q)", temp)
+
+	wdRelDir := filepath.VolumeName(temp) + `dir\sub` // no backslash after volume.
+	absLink := filepath.Join(temp, "link")
+	err = os.Symlink(wdRelDir, absLink)
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Logf("Symlink(%#q, %#q)", wdRelDir, absLink)
+
+	// Now change back to the original working directory and verify that the
+	// symlink still refers to its original path and is correctly marked as a
+	// directory.
+	if err := os.Chdir(oldwd); err != nil {
+		t.Fatal(err)
+	}
+	t.Logf("Chdir(%#q)", oldwd)
+
+	resolved, err := os.Readlink(absLink)
+	if err != nil {
+		t.Errorf("Readlink(%#q): %v", absLink, err)
+	} else if resolved != absDir {
+		t.Errorf("Readlink(%#q) = %#q; want %#q", absLink, resolved, absDir)
+	}
+
+	linkFile, err := os.Open(absLink)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer linkFile.Close()
+
+	linkInfo, err := linkFile.Stat()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !linkInfo.IsDir() {
+		t.Errorf("Open(%#q).Stat().IsDir() = false; want true", absLink)
+	}
+
+	absInfo, err := os.Stat(absDir)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if !os.SameFile(absInfo, linkInfo) {
+		t.Errorf("SameFile(Stat(%#q), Open(%#q).Stat()) = false; want true", absDir, absLink)
+	}
+}
+
+// TestStatOfInvalidName is regression test for issue #24999.
+func TestStatOfInvalidName(t *testing.T) {
+	t.Parallel()
+
+	_, err := os.Stat("*.go")
+	if err == nil {
+		t.Fatal(`os.Stat("*.go") unexpectedly succeeded`)
+	}
+}
+
+// findUnusedDriveLetter searches mounted drive list on the system
+// (starting from Z: and ending at D:) for unused drive letter.
+// It returns path to the found drive root directory (like Z:\) or error.
+func findUnusedDriveLetter() (string, error) {
+	// Do not use A: and B:, because they are reserved for floppy drive.
+	// Do not use C:, because it is normally used for main drive.
+	for l := 'Z'; l >= 'D'; l-- {
+		p := string(l) + `:\`
+		_, err := os.Stat(p)
+		if os.IsNotExist(err) {
+			return p, nil
+		}
+	}
+	return "", errors.New("Could not find unused drive letter.")
+}
+
+func TestRootDirAsTemp(t *testing.T) {
+	if os.Getenv("GO_WANT_HELPER_PROCESS") == "1" {
+		fmt.Print(os.TempDir())
+		os.Exit(0)
+	}
+
+	testenv.MustHaveExec(t)
+	t.Parallel()
+
+	exe, err := os.Executable()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	newtmp, err := findUnusedDriveLetter()
+	if err != nil {
+		t.Skip(err)
+	}
+
+	cmd := testenv.Command(t, exe, "-test.run=TestRootDirAsTemp")
+	cmd.Env = cmd.Environ()
+	cmd.Env = append(cmd.Env, "GO_WANT_HELPER_PROCESS=1")
+	cmd.Env = append(cmd.Env, "TMP="+newtmp)
+	cmd.Env = append(cmd.Env, "TEMP="+newtmp)
+	output, err := cmd.CombinedOutput()
+	if err != nil {
+		t.Fatalf("Failed to spawn child process: %v %q", err, string(output))
+	}
+	if want, have := newtmp, string(output); have != want {
+		t.Fatalf("unexpected child process output %q, want %q", have, want)
+	}
+}
+
+func testReadlink(t *testing.T, path, want string) {
+	got, err := os.Readlink(path)
+	if err != nil {
+		t.Error(err)
+		return
+	}
+	if got != want {
+		t.Errorf(`Readlink(%q): got %q, want %q`, path, got, want)
+	}
+}
+
+func mklink(t *testing.T, link, target string) {
+	output, err := testenv.Command(t, "cmd", "/c", "mklink", link, target).CombinedOutput()
+	if err != nil {
+		t.Fatalf("failed to run mklink %v %v: %v %q", link, target, err, output)
+	}
+}
+
+func mklinkj(t *testing.T, link, target string) {
+	output, err := testenv.Command(t, "cmd", "/c", "mklink", "/J", link, target).CombinedOutput()
+	if err != nil {
+		t.Fatalf("failed to run mklink %v %v: %v %q", link, target, err, output)
+	}
+}
+
+func mklinkd(t *testing.T, link, target string) {
+	output, err := testenv.Command(t, "cmd", "/c", "mklink", "/D", link, target).CombinedOutput()
+	if err != nil {
+		t.Fatalf("failed to run mklink %v %v: %v %q", link, target, err, output)
+	}
+}
+
+func TestWindowsReadlink(t *testing.T) {
+	tmpdir, err := os.MkdirTemp("", "TestWindowsReadlink")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.RemoveAll(tmpdir)
+
+	// Make sure tmpdir is not a symlink, otherwise tests will fail.
+	tmpdir, err = filepath.EvalSymlinks(tmpdir)
+	if err != nil {
+		t.Fatal(err)
+	}
+	chdir(t, tmpdir)
+
+	vol := filepath.VolumeName(tmpdir)
+	output, err := testenv.Command(t, "cmd", "/c", "mountvol", vol, "/L").CombinedOutput()
+	if err != nil {
+		t.Fatalf("failed to run mountvol %v /L: %v %q", vol, err, output)
+	}
+	ntvol := strings.Trim(string(output), " \n\r")
+
+	dir := filepath.Join(tmpdir, "dir")
+	err = os.MkdirAll(dir, 0777)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	absdirjlink := filepath.Join(tmpdir, "absdirjlink")
+	mklinkj(t, absdirjlink, dir)
+	testReadlink(t, absdirjlink, dir)
+
+	ntdirjlink := filepath.Join(tmpdir, "ntdirjlink")
+	mklinkj(t, ntdirjlink, ntvol+absdirjlink[len(filepath.VolumeName(absdirjlink)):])
+	testReadlink(t, ntdirjlink, absdirjlink)
+
+	ntdirjlinktolink := filepath.Join(tmpdir, "ntdirjlinktolink")
+	mklinkj(t, ntdirjlinktolink, ntvol+absdirjlink[len(filepath.VolumeName(absdirjlink)):])
+	testReadlink(t, ntdirjlinktolink, absdirjlink)
+
+	mklinkj(t, "reldirjlink", "dir")
+	testReadlink(t, "reldirjlink", dir) // relative directory junction resolves to absolute path
+
+	// Make sure we have sufficient privilege to run mklink command.
+	testenv.MustHaveSymlink(t)
+
+	absdirlink := filepath.Join(tmpdir, "absdirlink")
+	mklinkd(t, absdirlink, dir)
+	testReadlink(t, absdirlink, dir)
+
+	ntdirlink := filepath.Join(tmpdir, "ntdirlink")
+	mklinkd(t, ntdirlink, ntvol+absdirlink[len(filepath.VolumeName(absdirlink)):])
+	testReadlink(t, ntdirlink, absdirlink)
+
+	mklinkd(t, "reldirlink", "dir")
+	testReadlink(t, "reldirlink", "dir")
+
+	file := filepath.Join(tmpdir, "file")
+	err = os.WriteFile(file, []byte(""), 0666)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	filelink := filepath.Join(tmpdir, "filelink")
+	mklink(t, filelink, file)
+	testReadlink(t, filelink, file)
+
+	linktofilelink := filepath.Join(tmpdir, "linktofilelink")
+	mklink(t, linktofilelink, ntvol+filelink[len(filepath.VolumeName(filelink)):])
+	testReadlink(t, linktofilelink, filelink)
+
+	mklink(t, "relfilelink", "file")
+	testReadlink(t, "relfilelink", "file")
+}
+
+func TestOpenDirTOCTOU(t *testing.T) {
+	t.Parallel()
+
+	// Check opened directories can't be renamed until the handle is closed.
+	// See issue 52747.
+	tmpdir := t.TempDir()
+	dir := filepath.Join(tmpdir, "dir")
+	if err := os.Mkdir(dir, 0777); err != nil {
+		t.Fatal(err)
+	}
+	f, err := os.Open(dir)
+	if err != nil {
+		t.Fatal(err)
+	}
+	newpath := filepath.Join(tmpdir, "dir1")
+	err = os.Rename(dir, newpath)
+	if err == nil || !errors.Is(err, windows.ERROR_SHARING_VIOLATION) {
+		f.Close()
+		t.Fatalf("Rename(%q, %q) = %v; want windows.ERROR_SHARING_VIOLATION", dir, newpath, err)
+	}
+	f.Close()
+	err = os.Rename(dir, newpath)
+	if err != nil {
+		t.Error(err)
+	}
+}
+
+func TestAppExecLinkStat(t *testing.T) {
+	// We expect executables installed to %LOCALAPPDATA%\Microsoft\WindowsApps to
+	// be reparse points with tag IO_REPARSE_TAG_APPEXECLINK. Here we check that
+	// such reparse points are treated as irregular (but executable) files, not
+	// broken symlinks.
+	appdata := os.Getenv("LOCALAPPDATA")
+	if appdata == "" {
+		t.Skipf("skipping: LOCALAPPDATA not set")
+	}
+
+	pythonExeName := "python3.exe"
+	pythonPath := filepath.Join(appdata, `Microsoft\WindowsApps`, pythonExeName)
+
+	lfi, err := os.Lstat(pythonPath)
+	if err != nil {
+		t.Skip("skipping test, because Python 3 is not installed via the Windows App Store on this system; see https://golang.org/issue/42919")
+	}
+
+	// An APPEXECLINK reparse point is not a symlink, so os.Readlink should return
+	// a non-nil error for it, and Stat should return results identical to Lstat.
+	linkName, err := os.Readlink(pythonPath)
+	if err == nil {
+		t.Errorf("os.Readlink(%q) = %q, but expected an error\n(should be an APPEXECLINK reparse point, not a symlink)", pythonPath, linkName)
+	}
+
+	sfi, err := os.Stat(pythonPath)
+	if err != nil {
+		t.Fatalf("Stat %s: %v", pythonPath, err)
+	}
+
+	if lfi.Name() != sfi.Name() {
+		t.Logf("os.Lstat(%q) = %+v", pythonPath, lfi)
+		t.Logf("os.Stat(%q)  = %+v", pythonPath, sfi)
+		t.Errorf("files should be same")
+	}
+
+	if lfi.Name() != pythonExeName {
+		t.Errorf("Stat %s: got %q, but wanted %q", pythonPath, lfi.Name(), pythonExeName)
+	}
+	if m := lfi.Mode(); m&fs.ModeSymlink != 0 {
+		t.Errorf("%q should be a file, not a link (mode=0x%x)", pythonPath, uint32(m))
+	}
+	if m := lfi.Mode(); m&fs.ModeDir != 0 {
+		t.Errorf("%q should be a file, not a directory (mode=0x%x)", pythonPath, uint32(m))
+	}
+	if m := lfi.Mode(); m&fs.ModeIrregular == 0 {
+		// A reparse point is not a regular file, but we don't have a more appropriate
+		// ModeType bit for it, so it should be marked as irregular.
+		t.Errorf("%q should not be a regular file (mode=0x%x)", pythonPath, uint32(m))
+	}
+
+	if sfi.Name() != pythonExeName {
+		t.Errorf("Stat %s: got %q, but wanted %q", pythonPath, sfi.Name(), pythonExeName)
+	}
+	if m := sfi.Mode(); m&fs.ModeSymlink != 0 {
+		t.Errorf("%q should be a file, not a link (mode=0x%x)", pythonPath, uint32(m))
+	}
+	if m := sfi.Mode(); m&fs.ModeDir != 0 {
+		t.Errorf("%q should be a file, not a directory (mode=0x%x)", pythonPath, uint32(m))
+	}
+	if m := sfi.Mode(); m&fs.ModeIrregular == 0 {
+		// A reparse point is not a regular file, but we don't have a more appropriate
+		// ModeType bit for it, so it should be marked as irregular.
+		t.Errorf("%q should not be a regular file (mode=0x%x)", pythonPath, uint32(m))
+	}
+
+	p, err := exec.LookPath(pythonPath)
+	if err != nil {
+		t.Errorf("exec.LookPath(%q): %v", pythonPath, err)
+	}
+	if p != pythonPath {
+		t.Errorf("exec.LookPath(%q) = %q; want %q", pythonPath, p, pythonPath)
+	}
+}
+
+func TestIllformedUTF16FileName(t *testing.T) {
+	dir := t.TempDir()
+	const sep = string(os.PathSeparator)
+	if !strings.HasSuffix(dir, sep) {
+		dir += sep
+	}
+
+	// This UTF-16 file name is ill-formed as it contains low surrogates that are not preceded by high surrogates ([1:5]).
+	namew := []uint16{0x2e, 0xdc6d, 0xdc73, 0xdc79, 0xdc73, 0x30, 0x30, 0x30, 0x31, 0}
+
+	// Create a file whose name contains unpaired surrogates.
+	// Use syscall.CreateFile instead of os.Create to simulate a file that is created by
+	// a non-Go program so the file name hasn't gone through syscall.UTF16FromString.
+	dirw := utf16.Encode([]rune(dir))
+	pathw := append(dirw, namew...)
+	fd, err := syscall.CreateFile(&pathw[0], syscall.GENERIC_ALL, 0, nil, syscall.CREATE_NEW, 0, 0)
+	if err != nil {
+		t.Fatal(err)
+	}
+	syscall.CloseHandle(fd)
+
+	name := syscall.UTF16ToString(namew)
+	path := filepath.Join(dir, name)
+	// Verify that os.Lstat can query the file.
+	fi, err := os.Lstat(path)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got := fi.Name(); got != name {
+		t.Errorf("got %q, want %q", got, name)
+	}
+	// Verify that File.Readdirnames lists the file.
+	f, err := os.Open(dir)
+	if err != nil {
+		t.Fatal(err)
+	}
+	files, err := f.Readdirnames(0)
+	f.Close()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !slices.Contains(files, name) {
+		t.Error("file not listed")
+	}
+	// Verify that os.RemoveAll can remove the directory
+	// and that it doesn't hang.
+	err = os.RemoveAll(dir)
+	if err != nil {
+		t.Error(err)
+	}
+}
+
+func TestUTF16Alloc(t *testing.T) {
+	allowsPerRun := func(want int, f func()) {
+		t.Helper()
+		got := int(testing.AllocsPerRun(5, f))
+		if got != want {
+			t.Errorf("got %d allocs, want %d", got, want)
+		}
+	}
+	allowsPerRun(1, func() {
+		syscall.UTF16ToString([]uint16{'a', 'b', 'c'})
+	})
+	allowsPerRun(1, func() {
+		syscall.UTF16FromString("abc")
+	})
+}
+
+func TestNewFileInvalid(t *testing.T) {
+	t.Parallel()
+	if f := os.NewFile(uintptr(syscall.InvalidHandle), "invalid"); f != nil {
+		t.Errorf("NewFile(InvalidHandle) got %v want nil", f)
+	}
+}
+
+func TestReadDirPipe(t *testing.T) {
+	dir := `\\.\pipe\`
+	fi, err := os.Stat(dir)
+	if err != nil || !fi.IsDir() {
+		t.Skipf("%s is not a directory", dir)
+	}
+	_, err = os.ReadDir(dir)
+	if err != nil {
+		t.Errorf("ReadDir(%q) = %v", dir, err)
+	}
+}