1// Copyright 2014 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5package os_test
6
7import (
8	"errors"
9	"fmt"
10	"internal/godebug"
11	"internal/poll"
12	"internal/syscall/windows"
13	"internal/syscall/windows/registry"
14	"internal/testenv"
15	"io"
16	"io/fs"
17	"os"
18	"os/exec"
19	"path/filepath"
20	"reflect"
21	"runtime"
22	"slices"
23	"strings"
24	"syscall"
25	"testing"
26	"unicode/utf16"
27	"unsafe"
28)
29
30var winsymlink = godebug.New("winsymlink")
31var winreadlinkvolume = godebug.New("winreadlinkvolume")
32
33// For TestRawConnReadWrite.
34type syscallDescriptor = syscall.Handle
35
36// chdir changes the current working directory to the named directory,
37// and then restore the original working directory at the end of the test.
38func chdir(t *testing.T, dir string) {
39	olddir, err := os.Getwd()
40	if err != nil {
41		t.Fatalf("chdir: %v", err)
42	}
43	if err := os.Chdir(dir); err != nil {
44		t.Fatalf("chdir %s: %v", dir, err)
45	}
46
47	t.Cleanup(func() {
48		if err := os.Chdir(olddir); err != nil {
49			t.Errorf("chdir to original working directory %s: %v", olddir, err)
50			os.Exit(1)
51		}
52	})
53}
54
55func TestSameWindowsFile(t *testing.T) {
56	temp := t.TempDir()
57	chdir(t, temp)
58
59	f, err := os.Create("a")
60	if err != nil {
61		t.Fatal(err)
62	}
63	f.Close()
64
65	ia1, err := os.Stat("a")
66	if err != nil {
67		t.Fatal(err)
68	}
69
70	path, err := filepath.Abs("a")
71	if err != nil {
72		t.Fatal(err)
73	}
74	ia2, err := os.Stat(path)
75	if err != nil {
76		t.Fatal(err)
77	}
78	if !os.SameFile(ia1, ia2) {
79		t.Errorf("files should be same")
80	}
81
82	p := filepath.VolumeName(path) + filepath.Base(path)
83	if err != nil {
84		t.Fatal(err)
85	}
86	ia3, err := os.Stat(p)
87	if err != nil {
88		t.Fatal(err)
89	}
90	if !os.SameFile(ia1, ia3) {
91		t.Errorf("files should be same")
92	}
93}
94
95type dirLinkTest struct {
96	name         string
97	mklink       func(link, target string) error
98	isMountPoint bool
99}
100
101func testDirLinks(t *testing.T, tests []dirLinkTest) {
102	tmpdir := t.TempDir()
103	chdir(t, tmpdir)
104
105	dir := filepath.Join(tmpdir, "dir")
106	err := os.Mkdir(dir, 0777)
107	if err != nil {
108		t.Fatal(err)
109	}
110	fi, err := os.Stat(dir)
111	if err != nil {
112		t.Fatal(err)
113	}
114	err = os.WriteFile(filepath.Join(dir, "abc"), []byte("abc"), 0644)
115	if err != nil {
116		t.Fatal(err)
117	}
118	for _, test := range tests {
119		link := filepath.Join(tmpdir, test.name+"_link")
120		err := test.mklink(link, dir)
121		if err != nil {
122			t.Errorf("creating link for %q test failed: %v", test.name, err)
123			continue
124		}
125
126		data, err := os.ReadFile(filepath.Join(link, "abc"))
127		if err != nil {
128			t.Errorf("failed to read abc file: %v", err)
129			continue
130		}
131		if string(data) != "abc" {
132			t.Errorf(`abc file is expected to have "abc" in it, but has %v`, data)
133			continue
134		}
135
136		fi1, err := os.Stat(link)
137		if err != nil {
138			t.Errorf("failed to stat link %v: %v", link, err)
139			continue
140		}
141		if tp := fi1.Mode().Type(); tp != fs.ModeDir {
142			t.Errorf("Stat(%q) is type %v; want %v", link, tp, fs.ModeDir)
143			continue
144		}
145		if fi1.Name() != filepath.Base(link) {
146			t.Errorf("Stat(%q).Name() = %q, want %q", link, fi1.Name(), filepath.Base(link))
147			continue
148		}
149		if !os.SameFile(fi, fi1) {
150			t.Errorf("%q should point to %q", link, dir)
151			continue
152		}
153
154		fi2, err := os.Lstat(link)
155		if err != nil {
156			t.Errorf("failed to lstat link %v: %v", link, err)
157			continue
158		}
159		var wantType fs.FileMode
160		if test.isMountPoint && winsymlink.Value() != "0" {
161			// Mount points are reparse points, and we no longer treat them as symlinks.
162			wantType = fs.ModeIrregular
163		} else {
164			// This is either a real symlink, or a mount point treated as a symlink.
165			wantType = fs.ModeSymlink
166		}
167		if tp := fi2.Mode().Type(); tp != wantType {
168			t.Errorf("Lstat(%q) is type %v; want %v", link, tp, wantType)
169		}
170	}
171}
172
173// reparseData is used to build reparse buffer data required for tests.
174type reparseData struct {
175	substituteName namePosition
176	printName      namePosition
177	pathBuf        []uint16
178}
179
180type namePosition struct {
181	offset uint16
182	length uint16
183}
184
185func (rd *reparseData) addUTF16s(s []uint16) (offset uint16) {
186	off := len(rd.pathBuf) * 2
187	rd.pathBuf = append(rd.pathBuf, s...)
188	return uint16(off)
189}
190
191func (rd *reparseData) addString(s string) (offset, length uint16) {
192	p := syscall.StringToUTF16(s)
193	return rd.addUTF16s(p), uint16(len(p)-1) * 2 // do not include terminating NUL in the length (as per PrintNameLength and SubstituteNameLength documentation)
194}
195
196func (rd *reparseData) addSubstituteName(name string) {
197	rd.substituteName.offset, rd.substituteName.length = rd.addString(name)
198}
199
200func (rd *reparseData) addPrintName(name string) {
201	rd.printName.offset, rd.printName.length = rd.addString(name)
202}
203
204func (rd *reparseData) addStringNoNUL(s string) (offset, length uint16) {
205	p := syscall.StringToUTF16(s)
206	p = p[:len(p)-1]
207	return rd.addUTF16s(p), uint16(len(p)) * 2
208}
209
210func (rd *reparseData) addSubstituteNameNoNUL(name string) {
211	rd.substituteName.offset, rd.substituteName.length = rd.addStringNoNUL(name)
212}
213
214func (rd *reparseData) addPrintNameNoNUL(name string) {
215	rd.printName.offset, rd.printName.length = rd.addStringNoNUL(name)
216}
217
218// pathBuffeLen returns length of rd pathBuf in bytes.
219func (rd *reparseData) pathBuffeLen() uint16 {
220	return uint16(len(rd.pathBuf)) * 2
221}
222
223// Windows REPARSE_DATA_BUFFER contains union member, and cannot be
224// translated into Go directly. _REPARSE_DATA_BUFFER type is to help
225// construct alternative versions of Windows REPARSE_DATA_BUFFER with
226// union part of SymbolicLinkReparseBuffer or MountPointReparseBuffer type.
227type _REPARSE_DATA_BUFFER struct {
228	header windows.REPARSE_DATA_BUFFER_HEADER
229	detail [syscall.MAXIMUM_REPARSE_DATA_BUFFER_SIZE]byte
230}
231
232func createDirLink(link string, rdb *_REPARSE_DATA_BUFFER) error {
233	err := os.Mkdir(link, 0777)
234	if err != nil {
235		return err
236	}
237
238	linkp := syscall.StringToUTF16(link)
239	fd, err := syscall.CreateFile(&linkp[0], syscall.GENERIC_WRITE, 0, nil, syscall.OPEN_EXISTING,
240		syscall.FILE_FLAG_OPEN_REPARSE_POINT|syscall.FILE_FLAG_BACKUP_SEMANTICS, 0)
241	if err != nil {
242		return err
243	}
244	defer syscall.CloseHandle(fd)
245
246	buflen := uint32(rdb.header.ReparseDataLength) + uint32(unsafe.Sizeof(rdb.header))
247	var bytesReturned uint32
248	return syscall.DeviceIoControl(fd, windows.FSCTL_SET_REPARSE_POINT,
249		(*byte)(unsafe.Pointer(&rdb.header)), buflen, nil, 0, &bytesReturned, nil)
250}
251
252func createMountPoint(link string, target *reparseData) error {
253	var buf *windows.MountPointReparseBuffer
254	buflen := uint16(unsafe.Offsetof(buf.PathBuffer)) + target.pathBuffeLen() // see ReparseDataLength documentation
255	byteblob := make([]byte, buflen)
256	buf = (*windows.MountPointReparseBuffer)(unsafe.Pointer(&byteblob[0]))
257	buf.SubstituteNameOffset = target.substituteName.offset
258	buf.SubstituteNameLength = target.substituteName.length
259	buf.PrintNameOffset = target.printName.offset
260	buf.PrintNameLength = target.printName.length
261	pbuflen := len(target.pathBuf)
262	copy((*[2048]uint16)(unsafe.Pointer(&buf.PathBuffer[0]))[:pbuflen:pbuflen], target.pathBuf)
263
264	var rdb _REPARSE_DATA_BUFFER
265	rdb.header.ReparseTag = windows.IO_REPARSE_TAG_MOUNT_POINT
266	rdb.header.ReparseDataLength = buflen
267	copy(rdb.detail[:], byteblob)
268
269	return createDirLink(link, &rdb)
270}
271
272func TestDirectoryJunction(t *testing.T) {
273	var tests = []dirLinkTest{
274		{
275			// Create link similar to what mklink does, by inserting \??\ at the front of absolute target.
276			name:         "standard",
277			isMountPoint: true,
278			mklink: func(link, target string) error {
279				var t reparseData
280				t.addSubstituteName(`\??\` + target)
281				t.addPrintName(target)
282				return createMountPoint(link, &t)
283			},
284		},
285		{
286			// Do as junction utility https://learn.microsoft.com/en-us/sysinternals/downloads/junction does - set PrintNameLength to 0.
287			name:         "have_blank_print_name",
288			isMountPoint: true,
289			mklink: func(link, target string) error {
290				var t reparseData
291				t.addSubstituteName(`\??\` + target)
292				t.addPrintName("")
293				return createMountPoint(link, &t)
294			},
295		},
296	}
297	output, _ := testenv.Command(t, "cmd", "/c", "mklink", "/?").Output()
298	mklinkSupportsJunctionLinks := strings.Contains(string(output), " /J ")
299	if mklinkSupportsJunctionLinks {
300		tests = append(tests,
301			dirLinkTest{
302				name:         "use_mklink_cmd",
303				isMountPoint: true,
304				mklink: func(link, target string) error {
305					output, err := testenv.Command(t, "cmd", "/c", "mklink", "/J", link, target).CombinedOutput()
306					if err != nil {
307						t.Errorf("failed to run mklink %v %v: %v %q", link, target, err, output)
308					}
309					return nil
310				},
311			},
312		)
313	} else {
314		t.Log(`skipping "use_mklink_cmd" test, mklink does not supports directory junctions`)
315	}
316	testDirLinks(t, tests)
317}
318
319func enableCurrentThreadPrivilege(privilegeName string) error {
320	ct, err := windows.GetCurrentThread()
321	if err != nil {
322		return err
323	}
324	var t syscall.Token
325	err = windows.OpenThreadToken(ct, syscall.TOKEN_QUERY|windows.TOKEN_ADJUST_PRIVILEGES, false, &t)
326	if err != nil {
327		return err
328	}
329	defer syscall.CloseHandle(syscall.Handle(t))
330
331	var tp windows.TOKEN_PRIVILEGES
332
333	privStr, err := syscall.UTF16PtrFromString(privilegeName)
334	if err != nil {
335		return err
336	}
337	err = windows.LookupPrivilegeValue(nil, privStr, &tp.Privileges[0].Luid)
338	if err != nil {
339		return err
340	}
341	tp.PrivilegeCount = 1
342	tp.Privileges[0].Attributes = windows.SE_PRIVILEGE_ENABLED
343	return windows.AdjustTokenPrivileges(t, false, &tp, 0, nil, nil)
344}
345
346func createSymbolicLink(link string, target *reparseData, isrelative bool) error {
347	var buf *windows.SymbolicLinkReparseBuffer
348	buflen := uint16(unsafe.Offsetof(buf.PathBuffer)) + target.pathBuffeLen() // see ReparseDataLength documentation
349	byteblob := make([]byte, buflen)
350	buf = (*windows.SymbolicLinkReparseBuffer)(unsafe.Pointer(&byteblob[0]))
351	buf.SubstituteNameOffset = target.substituteName.offset
352	buf.SubstituteNameLength = target.substituteName.length
353	buf.PrintNameOffset = target.printName.offset
354	buf.PrintNameLength = target.printName.length
355	if isrelative {
356		buf.Flags = windows.SYMLINK_FLAG_RELATIVE
357	}
358	pbuflen := len(target.pathBuf)
359	copy((*[2048]uint16)(unsafe.Pointer(&buf.PathBuffer[0]))[:pbuflen:pbuflen], target.pathBuf)
360
361	var rdb _REPARSE_DATA_BUFFER
362	rdb.header.ReparseTag = syscall.IO_REPARSE_TAG_SYMLINK
363	rdb.header.ReparseDataLength = buflen
364	copy(rdb.detail[:], byteblob)
365
366	return createDirLink(link, &rdb)
367}
368
369func TestDirectorySymbolicLink(t *testing.T) {
370	var tests []dirLinkTest
371	output, _ := testenv.Command(t, "cmd", "/c", "mklink", "/?").Output()
372	mklinkSupportsDirectorySymbolicLinks := strings.Contains(string(output), " /D ")
373	if mklinkSupportsDirectorySymbolicLinks {
374		tests = append(tests,
375			dirLinkTest{
376				name: "use_mklink_cmd",
377				mklink: func(link, target string) error {
378					output, err := testenv.Command(t, "cmd", "/c", "mklink", "/D", link, target).CombinedOutput()
379					if err != nil {
380						t.Errorf("failed to run mklink %v %v: %v %q", link, target, err, output)
381					}
382					return nil
383				},
384			},
385		)
386	} else {
387		t.Log(`skipping "use_mklink_cmd" test, mklink does not supports directory symbolic links`)
388	}
389
390	// The rest of these test requires SeCreateSymbolicLinkPrivilege to be held.
391	runtime.LockOSThread()
392	defer runtime.UnlockOSThread()
393
394	err := windows.ImpersonateSelf(windows.SecurityImpersonation)
395	if err != nil {
396		t.Fatal(err)
397	}
398	defer windows.RevertToSelf()
399
400	err = enableCurrentThreadPrivilege("SeCreateSymbolicLinkPrivilege")
401	if err != nil {
402		t.Skipf(`skipping some tests, could not enable "SeCreateSymbolicLinkPrivilege": %v`, err)
403	}
404	tests = append(tests,
405		dirLinkTest{
406			name: "use_os_pkg",
407			mklink: func(link, target string) error {
408				return os.Symlink(target, link)
409			},
410		},
411		dirLinkTest{
412			// Create link similar to what mklink does, by inserting \??\ at the front of absolute target.
413			name: "standard",
414			mklink: func(link, target string) error {
415				var t reparseData
416				t.addPrintName(target)
417				t.addSubstituteName(`\??\` + target)
418				return createSymbolicLink(link, &t, false)
419			},
420		},
421		dirLinkTest{
422			name: "relative",
423			mklink: func(link, target string) error {
424				var t reparseData
425				t.addSubstituteNameNoNUL(filepath.Base(target))
426				t.addPrintNameNoNUL(filepath.Base(target))
427				return createSymbolicLink(link, &t, true)
428			},
429		},
430	)
431	testDirLinks(t, tests)
432}
433
434func mustHaveWorkstation(t *testing.T) {
435	mar, err := windows.OpenSCManager(nil, nil, windows.SERVICE_QUERY_STATUS)
436	if err != nil {
437		return
438	}
439	defer syscall.CloseHandle(mar)
440	//LanmanWorkstation is the service name, and Workstation is the display name.
441	srv, err := windows.OpenService(mar, syscall.StringToUTF16Ptr("LanmanWorkstation"), windows.SERVICE_QUERY_STATUS)
442	if err != nil {
443		return
444	}
445	defer syscall.CloseHandle(srv)
446	var state windows.SERVICE_STATUS
447	err = windows.QueryServiceStatus(srv, &state)
448	if err != nil {
449		return
450	}
451	if state.CurrentState != windows.SERVICE_RUNNING {
452		t.Skip("Requires the Windows service Workstation, but it is detected that it is not enabled.")
453	}
454}
455
456func TestNetworkSymbolicLink(t *testing.T) {
457	testenv.MustHaveSymlink(t)
458
459	const _NERR_ServerNotStarted = syscall.Errno(2114)
460
461	dir := t.TempDir()
462	chdir(t, dir)
463
464	pid := os.Getpid()
465	shareName := fmt.Sprintf("GoSymbolicLinkTestShare%d", pid)
466	sharePath := filepath.Join(dir, shareName)
467	testDir := "TestDir"
468
469	err := os.MkdirAll(filepath.Join(sharePath, testDir), 0777)
470	if err != nil {
471		t.Fatal(err)
472	}
473
474	wShareName, err := syscall.UTF16PtrFromString(shareName)
475	if err != nil {
476		t.Fatal(err)
477	}
478	wSharePath, err := syscall.UTF16PtrFromString(sharePath)
479	if err != nil {
480		t.Fatal(err)
481	}
482
483	// Per https://learn.microsoft.com/en-us/windows/win32/api/lmshare/ns-lmshare-share_info_2:
484	//
485	// “[The shi2_permissions field] indicates the shared resource's permissions
486	// for servers running with share-level security. A server running user-level
487	// security ignores this member.
488	// …
489	// Note that Windows does not support share-level security.”
490	//
491	// So it shouldn't matter what permissions we set here.
492	const permissions = 0
493
494	p := windows.SHARE_INFO_2{
495		Netname:     wShareName,
496		Type:        windows.STYPE_DISKTREE | windows.STYPE_TEMPORARY,
497		Remark:      nil,
498		Permissions: permissions,
499		MaxUses:     1,
500		CurrentUses: 0,
501		Path:        wSharePath,
502		Passwd:      nil,
503	}
504
505	err = windows.NetShareAdd(nil, 2, (*byte)(unsafe.Pointer(&p)), nil)
506	if err != nil {
507		if err == syscall.ERROR_ACCESS_DENIED || err == _NERR_ServerNotStarted {
508			t.Skipf("skipping: NetShareAdd: %v", err)
509		}
510		t.Fatal(err)
511	}
512	defer func() {
513		err := windows.NetShareDel(nil, wShareName, 0)
514		if err != nil {
515			t.Fatal(err)
516		}
517	}()
518
519	UNCPath := `\\localhost\` + shareName + `\`
520
521	fi1, err := os.Stat(sharePath)
522	if err != nil {
523		t.Fatal(err)
524	}
525	fi2, err := os.Stat(UNCPath)
526	if err != nil {
527		mustHaveWorkstation(t)
528		t.Fatal(err)
529	}
530	if !os.SameFile(fi1, fi2) {
531		t.Fatalf("%q and %q should be the same directory, but not", sharePath, UNCPath)
532	}
533
534	target := filepath.Join(UNCPath, testDir)
535	link := "link"
536
537	err = os.Symlink(target, link)
538	if err != nil {
539		t.Fatal(err)
540	}
541	defer os.Remove(link)
542
543	got, err := os.Readlink(link)
544	if err != nil {
545		t.Fatal(err)
546	}
547	if got != target {
548		t.Errorf(`os.Readlink(%#q): got %v, want %v`, link, got, target)
549	}
550
551	got, err = filepath.EvalSymlinks(link)
552	if err != nil {
553		t.Fatal(err)
554	}
555	if got != target {
556		t.Errorf(`filepath.EvalSymlinks(%#q): got %v, want %v`, link, got, target)
557	}
558}
559
560func TestStatLxSymLink(t *testing.T) {
561	if _, err := exec.LookPath("wsl"); err != nil {
562		t.Skip("skipping: WSL not detected")
563	}
564
565	temp := t.TempDir()
566	chdir(t, temp)
567
568	const target = "target"
569	const link = "link"
570
571	_, err := testenv.Command(t, "wsl", "/bin/mkdir", target).Output()
572	if err != nil {
573		// This normally happens when WSL still doesn't have a distro installed to run on.
574		t.Skipf("skipping: WSL is not correctly installed: %v", err)
575	}
576
577	_, err = testenv.Command(t, "wsl", "/bin/ln", "-s", target, link).Output()
578	if err != nil {
579		t.Fatal(err)
580	}
581
582	fi, err := os.Lstat(link)
583	if err != nil {
584		t.Fatal(err)
585	}
586	if m := fi.Mode(); m&fs.ModeSymlink != 0 {
587		// This can happen depending on newer WSL versions when running as admin or in developer mode.
588		t.Skip("skipping: WSL created reparse tag IO_REPARSE_TAG_SYMLINK instead of an IO_REPARSE_TAG_LX_SYMLINK")
589	}
590	// Stat'ing a IO_REPARSE_TAG_LX_SYMLINK from outside WSL always return ERROR_CANT_ACCESS_FILE.
591	// We check this condition to validate that os.Stat has tried to follow the link.
592	_, err = os.Stat(link)
593	const ERROR_CANT_ACCESS_FILE = syscall.Errno(1920)
594	if err == nil || !errors.Is(err, ERROR_CANT_ACCESS_FILE) {
595		t.Fatalf("os.Stat(%q): got %v, want ERROR_CANT_ACCESS_FILE", link, err)
596	}
597}
598
599func TestStartProcessAttr(t *testing.T) {
600	t.Parallel()
601
602	p, err := os.StartProcess(os.Getenv("COMSPEC"), []string{"/c", "cd"}, new(os.ProcAttr))
603	if err != nil {
604		return
605	}
606	defer p.Wait()
607	t.Fatalf("StartProcess expected to fail, but succeeded.")
608}
609
610func TestShareNotExistError(t *testing.T) {
611	if testing.Short() {
612		t.Skip("slow test that uses network; skipping")
613	}
614	t.Parallel()
615
616	_, err := os.Stat(`\\no_such_server\no_such_share\no_such_file`)
617	if err == nil {
618		t.Fatal("stat succeeded, but expected to fail")
619	}
620	if !os.IsNotExist(err) {
621		t.Fatalf("os.Stat failed with %q, but os.IsNotExist(err) is false", err)
622	}
623}
624
625func TestBadNetPathError(t *testing.T) {
626	const ERROR_BAD_NETPATH = syscall.Errno(53)
627	if !os.IsNotExist(ERROR_BAD_NETPATH) {
628		t.Fatal("os.IsNotExist(syscall.Errno(53)) is false, but want true")
629	}
630}
631
632func TestStatDir(t *testing.T) {
633	defer chtmpdir(t)()
634
635	f, err := os.Open(".")
636	if err != nil {
637		t.Fatal(err)
638	}
639	defer f.Close()
640
641	fi, err := f.Stat()
642	if err != nil {
643		t.Fatal(err)
644	}
645
646	err = os.Chdir("..")
647	if err != nil {
648		t.Fatal(err)
649	}
650
651	fi2, err := f.Stat()
652	if err != nil {
653		t.Fatal(err)
654	}
655
656	if !os.SameFile(fi, fi2) {
657		t.Fatal("race condition occurred")
658	}
659}
660
661func TestOpenVolumeName(t *testing.T) {
662	tmpdir := t.TempDir()
663	chdir(t, tmpdir)
664
665	want := []string{"file1", "file2", "file3", "gopher.txt"}
666	slices.Sort(want)
667	for _, name := range want {
668		err := os.WriteFile(filepath.Join(tmpdir, name), nil, 0777)
669		if err != nil {
670			t.Fatal(err)
671		}
672	}
673
674	f, err := os.Open(filepath.VolumeName(tmpdir))
675	if err != nil {
676		t.Fatal(err)
677	}
678	defer f.Close()
679
680	have, err := f.Readdirnames(-1)
681	if err != nil {
682		t.Fatal(err)
683	}
684	slices.Sort(have)
685
686	if strings.Join(want, "/") != strings.Join(have, "/") {
687		t.Fatalf("unexpected file list %q, want %q", have, want)
688	}
689}
690
691func TestDeleteReadOnly(t *testing.T) {
692	t.Parallel()
693
694	tmpdir := t.TempDir()
695	p := filepath.Join(tmpdir, "a")
696	// This sets FILE_ATTRIBUTE_READONLY.
697	f, err := os.OpenFile(p, os.O_CREATE, 0400)
698	if err != nil {
699		t.Fatal(err)
700	}
701	f.Close()
702
703	if err = os.Chmod(p, 0400); err != nil {
704		t.Fatal(err)
705	}
706	if err = os.Remove(p); err != nil {
707		t.Fatal(err)
708	}
709}
710
711func TestReadStdin(t *testing.T) {
712	old := poll.ReadConsole
713	defer func() {
714		poll.ReadConsole = old
715	}()
716
717	p, err := syscall.GetCurrentProcess()
718	if err != nil {
719		t.Fatalf("Unable to get handle to current process: %v", err)
720	}
721	var stdinDuplicate syscall.Handle
722	err = syscall.DuplicateHandle(p, syscall.Handle(syscall.Stdin), p, &stdinDuplicate, 0, false, syscall.DUPLICATE_SAME_ACCESS)
723	if err != nil {
724		t.Fatalf("Unable to duplicate stdin: %v", err)
725	}
726	testConsole := os.NewConsoleFile(stdinDuplicate, "test")
727
728	var tests = []string{
729		"abc",
730		"äöü",
731		"\u3042",
732		"“hi”™",
733		"hello\x1aworld",
734		"\U0001F648\U0001F649\U0001F64A",
735	}
736
737	for _, consoleSize := range []int{1, 2, 3, 10, 16, 100, 1000} {
738		for _, readSize := range []int{1, 2, 3, 4, 5, 8, 10, 16, 20, 50, 100} {
739			for _, s := range tests {
740				t.Run(fmt.Sprintf("c%d/r%d/%s", consoleSize, readSize, s), func(t *testing.T) {
741					s16 := utf16.Encode([]rune(s))
742					poll.ReadConsole = func(h syscall.Handle, buf *uint16, toread uint32, read *uint32, inputControl *byte) error {
743						if inputControl != nil {
744							t.Fatalf("inputControl not nil")
745						}
746						n := int(toread)
747						if n > consoleSize {
748							n = consoleSize
749						}
750						n = copy((*[10000]uint16)(unsafe.Pointer(buf))[:n:n], s16)
751						s16 = s16[n:]
752						*read = uint32(n)
753						t.Logf("read %d -> %d", toread, *read)
754						return nil
755					}
756
757					var all []string
758					var buf []byte
759					chunk := make([]byte, readSize)
760					for {
761						n, err := testConsole.Read(chunk)
762						buf = append(buf, chunk[:n]...)
763						if err == io.EOF {
764							all = append(all, string(buf))
765							if len(all) >= 5 {
766								break
767							}
768							buf = buf[:0]
769						} else if err != nil {
770							t.Fatalf("reading %q: error: %v", s, err)
771						}
772						if len(buf) >= 2000 {
773							t.Fatalf("reading %q: stuck in loop: %q", s, buf)
774						}
775					}
776
777					want := strings.Split(s, "\x1a")
778					for len(want) < 5 {
779						want = append(want, "")
780					}
781					if !reflect.DeepEqual(all, want) {
782						t.Errorf("reading %q:\nhave %x\nwant %x", s, all, want)
783					}
784				})
785			}
786		}
787	}
788}
789
790func TestStatPagefile(t *testing.T) {
791	t.Parallel()
792
793	const path = `c:\pagefile.sys`
794	fi, err := os.Stat(path)
795	if err == nil {
796		if fi.Name() == "" {
797			t.Fatalf("Stat(%q).Name() is empty", path)
798		}
799		t.Logf("Stat(%q).Size() = %v", path, fi.Size())
800		return
801	}
802	if os.IsNotExist(err) {
803		t.Skip(`skipping because c:\pagefile.sys is not found`)
804	}
805	t.Fatal(err)
806}
807
808// syscallCommandLineToArgv calls syscall.CommandLineToArgv
809// and converts returned result into []string.
810func syscallCommandLineToArgv(cmd string) ([]string, error) {
811	var argc int32
812	argv, err := syscall.CommandLineToArgv(&syscall.StringToUTF16(cmd)[0], &argc)
813	if err != nil {
814		return nil, err
815	}
816	defer syscall.LocalFree(syscall.Handle(uintptr(unsafe.Pointer(argv))))
817
818	var args []string
819	for _, v := range (*argv)[:argc] {
820		args = append(args, syscall.UTF16ToString((*v)[:]))
821	}
822	return args, nil
823}
824
825// compareCommandLineToArgvWithSyscall ensures that
826// os.CommandLineToArgv(cmd) and syscall.CommandLineToArgv(cmd)
827// return the same result.
828func compareCommandLineToArgvWithSyscall(t *testing.T, cmd string) {
829	syscallArgs, err := syscallCommandLineToArgv(cmd)
830	if err != nil {
831		t.Fatal(err)
832	}
833	args := os.CommandLineToArgv(cmd)
834	if want, have := fmt.Sprintf("%q", syscallArgs), fmt.Sprintf("%q", args); want != have {
835		t.Errorf("testing os.commandLineToArgv(%q) failed: have %q want %q", cmd, args, syscallArgs)
836		return
837	}
838}
839
840func TestCmdArgs(t *testing.T) {
841	if testing.Short() {
842		t.Skipf("in short mode; skipping test that builds a binary")
843	}
844	t.Parallel()
845
846	tmpdir := t.TempDir()
847
848	const prog = `
849package main
850
851import (
852	"fmt"
853	"os"
854)
855
856func main() {
857	fmt.Printf("%q", os.Args)
858}
859`
860	src := filepath.Join(tmpdir, "main.go")
861	if err := os.WriteFile(src, []byte(prog), 0666); err != nil {
862		t.Fatal(err)
863	}
864
865	exe := filepath.Join(tmpdir, "main.exe")
866	cmd := testenv.Command(t, testenv.GoToolPath(t), "build", "-o", exe, src)
867	cmd.Dir = tmpdir
868	out, err := cmd.CombinedOutput()
869	if err != nil {
870		t.Fatalf("building main.exe failed: %v\n%s", err, out)
871	}
872
873	var cmds = []string{
874		``,
875		` a b c`,
876		` "`,
877		` ""`,
878		` """`,
879		` "" a`,
880		` "123"`,
881		` \"123\"`,
882		` \"123 456\"`,
883		` \\"`,
884		` \\\"`,
885		` \\\\\"`,
886		` \\\"x`,
887		` """"\""\\\"`,
888		` abc`,
889		` \\\\\""x"""y z`,
890		"\tb\t\"x\ty\"",
891		` "Брад" d e`,
892		// examples from https://learn.microsoft.com/en-us/cpp/cpp/main-function-command-line-args
893		` "abc" d e`,
894		` a\\b d"e f"g h`,
895		` a\\\"b c d`,
896		` a\\\\"b c" d e`,
897		// http://daviddeley.com/autohotkey/parameters/parameters.htm#WINARGV
898		// from 5.4  Examples
899		` CallMeIshmael`,
900		` "Call Me Ishmael"`,
901		` Cal"l Me I"shmael`,
902		` CallMe\"Ishmael`,
903		` "CallMe\"Ishmael"`,
904		` "Call Me Ishmael\\"`,
905		` "CallMe\\\"Ishmael"`,
906		` a\\\b`,
907		` "a\\\b"`,
908		// from 5.5  Some Common Tasks
909		` "\"Call Me Ishmael\""`,
910		` "C:\TEST A\\"`,
911		` "\"C:\TEST A\\\""`,
912		// from 5.6  The Microsoft Examples Explained
913		` "a b c"  d  e`,
914		` "ab\"c"  "\\"  d`,
915		` a\\\b d"e f"g h`,
916		` a\\\"b c d`,
917		` a\\\\"b c" d e`,
918		// from 5.7  Double Double Quote Examples (pre 2008)
919		` "a b c""`,
920		` """CallMeIshmael"""  b  c`,
921		` """Call Me Ishmael"""`,
922		` """"Call Me Ishmael"" b c`,
923	}
924	for _, cmd := range cmds {
925		compareCommandLineToArgvWithSyscall(t, "test"+cmd)
926		compareCommandLineToArgvWithSyscall(t, `"cmd line"`+cmd)
927		compareCommandLineToArgvWithSyscall(t, exe+cmd)
928
929		// test both syscall.EscapeArg and os.commandLineToArgv
930		args := os.CommandLineToArgv(exe + cmd)
931		out, err := testenv.Command(t, args[0], args[1:]...).CombinedOutput()
932		if err != nil {
933			t.Fatalf("running %q failed: %v\n%v", args, err, string(out))
934		}
935		if want, have := fmt.Sprintf("%q", args), string(out); want != have {
936			t.Errorf("wrong output of executing %q: have %q want %q", args, have, want)
937			continue
938		}
939	}
940}
941
942func findOneDriveDir() (string, error) {
943	// as per https://stackoverflow.com/questions/42519624/how-to-determine-location-of-onedrive-on-windows-7-and-8-in-c
944	const onedrivekey = `SOFTWARE\Microsoft\OneDrive`
945	k, err := registry.OpenKey(registry.CURRENT_USER, onedrivekey, registry.READ)
946	if err != nil {
947		return "", fmt.Errorf("OpenKey(%q) failed: %v", onedrivekey, err)
948	}
949	defer k.Close()
950
951	path, valtype, err := k.GetStringValue("UserFolder")
952	if err != nil {
953		return "", fmt.Errorf("reading UserFolder failed: %v", err)
954	}
955
956	if valtype == registry.EXPAND_SZ {
957		expanded, err := registry.ExpandString(path)
958		if err != nil {
959			return "", fmt.Errorf("expanding UserFolder failed: %v", err)
960		}
961		path = expanded
962	}
963
964	return path, nil
965}
966
967// TestOneDrive verifies that OneDrive folder is a directory and not a symlink.
968func TestOneDrive(t *testing.T) {
969	t.Parallel()
970
971	dir, err := findOneDriveDir()
972	if err != nil {
973		t.Skipf("Skipping, because we did not find OneDrive directory: %v", err)
974	}
975	testDirStats(t, dir)
976}
977
978func TestWindowsDevNullFile(t *testing.T) {
979	t.Parallel()
980
981	f1, err := os.Open("NUL")
982	if err != nil {
983		t.Fatal(err)
984	}
985	defer f1.Close()
986
987	fi1, err := f1.Stat()
988	if err != nil {
989		t.Fatal(err)
990	}
991
992	f2, err := os.Open("nul")
993	if err != nil {
994		t.Fatal(err)
995	}
996	defer f2.Close()
997
998	fi2, err := f2.Stat()
999	if err != nil {
1000		t.Fatal(err)
1001	}
1002
1003	if !os.SameFile(fi1, fi2) {
1004		t.Errorf(`"NUL" and "nul" are not the same file`)
1005	}
1006}
1007
1008func TestFileStatNUL(t *testing.T) {
1009	t.Parallel()
1010
1011	f, err := os.Open("NUL")
1012	if err != nil {
1013		t.Fatal(err)
1014	}
1015	fi, err := f.Stat()
1016	if err != nil {
1017		t.Fatal(err)
1018	}
1019	if got, want := fi.Mode(), os.ModeDevice|os.ModeCharDevice|0666; got != want {
1020		t.Errorf("Open(%q).Stat().Mode() = %v, want %v", "NUL", got, want)
1021	}
1022}
1023
1024func TestStatNUL(t *testing.T) {
1025	t.Parallel()
1026
1027	fi, err := os.Stat("NUL")
1028	if err != nil {
1029		t.Fatal(err)
1030	}
1031	if got, want := fi.Mode(), os.ModeDevice|os.ModeCharDevice|0666; got != want {
1032		t.Errorf("Stat(%q).Mode() = %v, want %v", "NUL", got, want)
1033	}
1034}
1035
1036// TestSymlinkCreation verifies that creating a symbolic link
1037// works on Windows when developer mode is active.
1038// This is supported starting Windows 10 (1703, v10.0.14972).
1039func TestSymlinkCreation(t *testing.T) {
1040	if !testenv.HasSymlink() && !isWindowsDeveloperModeActive() {
1041		t.Skip("Windows developer mode is not active")
1042	}
1043	t.Parallel()
1044
1045	temp := t.TempDir()
1046	dummyFile := filepath.Join(temp, "file")
1047	if err := os.WriteFile(dummyFile, []byte(""), 0644); err != nil {
1048		t.Fatal(err)
1049	}
1050
1051	linkFile := filepath.Join(temp, "link")
1052	if err := os.Symlink(dummyFile, linkFile); err != nil {
1053		t.Fatal(err)
1054	}
1055}
1056
1057// isWindowsDeveloperModeActive checks whether or not the developer mode is active on Windows 10.
1058// Returns false for prior Windows versions.
1059// see https://docs.microsoft.com/en-us/windows/uwp/get-started/enable-your-device-for-development
1060func isWindowsDeveloperModeActive() bool {
1061	key, err := registry.OpenKey(registry.LOCAL_MACHINE, "SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\AppModelUnlock", registry.READ)
1062	if err != nil {
1063		return false
1064	}
1065
1066	val, _, err := key.GetIntegerValue("AllowDevelopmentWithoutDevLicense")
1067	if err != nil {
1068		return false
1069	}
1070
1071	return val != 0
1072}
1073
1074// TestRootRelativeDirSymlink verifies that symlinks to paths relative to the
1075// drive root (beginning with "\" but no volume name) are created with the
1076// correct symlink type.
1077// (See https://golang.org/issue/39183#issuecomment-632175728.)
1078func TestRootRelativeDirSymlink(t *testing.T) {
1079	testenv.MustHaveSymlink(t)
1080	t.Parallel()
1081
1082	temp := t.TempDir()
1083	dir := filepath.Join(temp, "dir")
1084	if err := os.Mkdir(dir, 0755); err != nil {
1085		t.Fatal(err)
1086	}
1087
1088	volumeRelDir := strings.TrimPrefix(dir, filepath.VolumeName(dir)) // leaves leading backslash
1089
1090	link := filepath.Join(temp, "link")
1091	err := os.Symlink(volumeRelDir, link)
1092	if err != nil {
1093		t.Fatal(err)
1094	}
1095	t.Logf("Symlink(%#q, %#q)", volumeRelDir, link)
1096
1097	f, err := os.Open(link)
1098	if err != nil {
1099		t.Fatal(err)
1100	}
1101	defer f.Close()
1102	if fi, err := f.Stat(); err != nil {
1103		t.Fatal(err)
1104	} else if !fi.IsDir() {
1105		t.Errorf("Open(%#q).Stat().IsDir() = false; want true", f.Name())
1106	}
1107}
1108
1109// TestWorkingDirectoryRelativeSymlink verifies that symlinks to paths relative
1110// to the current working directory for the drive, such as "C:File.txt", are
1111// correctly converted to absolute links of the correct symlink type (per
1112// https://docs.microsoft.com/en-us/windows/win32/fileio/creating-symbolic-links).
1113func TestWorkingDirectoryRelativeSymlink(t *testing.T) {
1114	testenv.MustHaveSymlink(t)
1115
1116	// Construct a directory to be symlinked.
1117	temp := t.TempDir()
1118	if v := filepath.VolumeName(temp); len(v) < 2 || v[1] != ':' {
1119		t.Skipf("Can't test relative symlinks: t.TempDir() (%#q) does not begin with a drive letter.", temp)
1120	}
1121
1122	absDir := filepath.Join(temp, `dir\sub`)
1123	if err := os.MkdirAll(absDir, 0755); err != nil {
1124		t.Fatal(err)
1125	}
1126
1127	// Change to the temporary directory and construct a
1128	// working-directory-relative symlink.
1129	oldwd, err := os.Getwd()
1130	if err != nil {
1131		t.Fatal(err)
1132	}
1133	defer func() {
1134		if err := os.Chdir(oldwd); err != nil {
1135			t.Fatal(err)
1136		}
1137	}()
1138	if err := os.Chdir(temp); err != nil {
1139		t.Fatal(err)
1140	}
1141	t.Logf("Chdir(%#q)", temp)
1142
1143	wdRelDir := filepath.VolumeName(temp) + `dir\sub` // no backslash after volume.
1144	absLink := filepath.Join(temp, "link")
1145	err = os.Symlink(wdRelDir, absLink)
1146	if err != nil {
1147		t.Fatal(err)
1148	}
1149	t.Logf("Symlink(%#q, %#q)", wdRelDir, absLink)
1150
1151	// Now change back to the original working directory and verify that the
1152	// symlink still refers to its original path and is correctly marked as a
1153	// directory.
1154	if err := os.Chdir(oldwd); err != nil {
1155		t.Fatal(err)
1156	}
1157	t.Logf("Chdir(%#q)", oldwd)
1158
1159	resolved, err := os.Readlink(absLink)
1160	if err != nil {
1161		t.Errorf("Readlink(%#q): %v", absLink, err)
1162	} else if resolved != absDir {
1163		t.Errorf("Readlink(%#q) = %#q; want %#q", absLink, resolved, absDir)
1164	}
1165
1166	linkFile, err := os.Open(absLink)
1167	if err != nil {
1168		t.Fatal(err)
1169	}
1170	defer linkFile.Close()
1171
1172	linkInfo, err := linkFile.Stat()
1173	if err != nil {
1174		t.Fatal(err)
1175	}
1176	if !linkInfo.IsDir() {
1177		t.Errorf("Open(%#q).Stat().IsDir() = false; want true", absLink)
1178	}
1179
1180	absInfo, err := os.Stat(absDir)
1181	if err != nil {
1182		t.Fatal(err)
1183	}
1184
1185	if !os.SameFile(absInfo, linkInfo) {
1186		t.Errorf("SameFile(Stat(%#q), Open(%#q).Stat()) = false; want true", absDir, absLink)
1187	}
1188}
1189
1190// TestStatOfInvalidName is regression test for issue #24999.
1191func TestStatOfInvalidName(t *testing.T) {
1192	t.Parallel()
1193
1194	_, err := os.Stat("*.go")
1195	if err == nil {
1196		t.Fatal(`os.Stat("*.go") unexpectedly succeeded`)
1197	}
1198}
1199
1200// findUnusedDriveLetter searches mounted drive list on the system
1201// (starting from Z: and ending at D:) for unused drive letter.
1202// It returns path to the found drive root directory (like Z:\) or error.
1203func findUnusedDriveLetter() (string, error) {
1204	// Do not use A: and B:, because they are reserved for floppy drive.
1205	// Do not use C:, because it is normally used for main drive.
1206	for l := 'Z'; l >= 'D'; l-- {
1207		p := string(l) + `:\`
1208		_, err := os.Stat(p)
1209		if os.IsNotExist(err) {
1210			return p, nil
1211		}
1212	}
1213	return "", errors.New("Could not find unused drive letter.")
1214}
1215
1216func TestRootDirAsTemp(t *testing.T) {
1217	if os.Getenv("GO_WANT_HELPER_PROCESS") == "1" {
1218		fmt.Print(os.TempDir())
1219		os.Exit(0)
1220	}
1221
1222	testenv.MustHaveExec(t)
1223	t.Parallel()
1224
1225	exe, err := os.Executable()
1226	if err != nil {
1227		t.Fatal(err)
1228	}
1229
1230	newtmp, err := findUnusedDriveLetter()
1231	if err != nil {
1232		t.Skip(err)
1233	}
1234
1235	cmd := testenv.Command(t, exe, "-test.run=^TestRootDirAsTemp$")
1236	cmd.Env = cmd.Environ()
1237	cmd.Env = append(cmd.Env, "GO_WANT_HELPER_PROCESS=1")
1238	cmd.Env = append(cmd.Env, "TMP="+newtmp)
1239	cmd.Env = append(cmd.Env, "TEMP="+newtmp)
1240	output, err := cmd.CombinedOutput()
1241	if err != nil {
1242		t.Fatalf("Failed to spawn child process: %v %q", err, string(output))
1243	}
1244	if want, have := newtmp, string(output); have != want {
1245		t.Fatalf("unexpected child process output %q, want %q", have, want)
1246	}
1247}
1248
1249// replaceDriveWithVolumeID returns path with its volume name replaced with
1250// the mounted volume ID. E.g. C:\foo -> \\?\Volume{GUID}\foo.
1251func replaceDriveWithVolumeID(t *testing.T, path string) string {
1252	t.Helper()
1253	cmd := testenv.Command(t, "cmd", "/c", "mountvol", filepath.VolumeName(path), "/L")
1254	out, err := cmd.CombinedOutput()
1255	if err != nil {
1256		t.Fatalf("%v: %v\n%s", cmd, err, out)
1257	}
1258	vol := strings.Trim(string(out), " \n\r")
1259	return filepath.Join(vol, path[len(filepath.VolumeName(path)):])
1260}
1261
1262func TestReadlink(t *testing.T) {
1263	tests := []struct {
1264		junction bool
1265		dir      bool
1266		drive    bool
1267		relative bool
1268	}{
1269		{junction: true, dir: true, drive: true, relative: false},
1270		{junction: true, dir: true, drive: false, relative: false},
1271		{junction: true, dir: true, drive: false, relative: true},
1272		{junction: false, dir: true, drive: true, relative: false},
1273		{junction: false, dir: true, drive: false, relative: false},
1274		{junction: false, dir: true, drive: false, relative: true},
1275		{junction: false, dir: false, drive: true, relative: false},
1276		{junction: false, dir: false, drive: false, relative: false},
1277		{junction: false, dir: false, drive: false, relative: true},
1278	}
1279	for _, tt := range tests {
1280		tt := tt
1281		var name string
1282		if tt.junction {
1283			name = "junction"
1284		} else {
1285			name = "symlink"
1286		}
1287		if tt.dir {
1288			name += "_dir"
1289		} else {
1290			name += "_file"
1291		}
1292		if tt.drive {
1293			name += "_drive"
1294		} else {
1295			name += "_volume"
1296		}
1297		if tt.relative {
1298			name += "_relative"
1299		} else {
1300			name += "_absolute"
1301		}
1302
1303		t.Run(name, func(t *testing.T) {
1304			if !tt.relative {
1305				t.Parallel()
1306			}
1307			// Make sure tmpdir is not a symlink, otherwise tests will fail.
1308			tmpdir, err := filepath.EvalSymlinks(t.TempDir())
1309			if err != nil {
1310				t.Fatal(err)
1311			}
1312			link := filepath.Join(tmpdir, "link")
1313			target := filepath.Join(tmpdir, "target")
1314			if tt.dir {
1315				if err := os.MkdirAll(target, 0777); err != nil {
1316					t.Fatal(err)
1317				}
1318			} else {
1319				if err := os.WriteFile(target, nil, 0666); err != nil {
1320					t.Fatal(err)
1321				}
1322			}
1323			var want string
1324			if tt.relative {
1325				relTarget := filepath.Base(target)
1326				if tt.junction {
1327					want = target // relative directory junction resolves to absolute path
1328				} else {
1329					want = relTarget
1330				}
1331				chdir(t, tmpdir)
1332				link = filepath.Base(link)
1333				target = relTarget
1334			} else {
1335				if tt.drive {
1336					want = target
1337				} else {
1338					volTarget := replaceDriveWithVolumeID(t, target)
1339					if winreadlinkvolume.Value() == "0" {
1340						want = target
1341					} else {
1342						want = volTarget
1343					}
1344					target = volTarget
1345				}
1346			}
1347			if tt.junction {
1348				cmd := testenv.Command(t, "cmd", "/c", "mklink", "/J", link, target)
1349				if out, err := cmd.CombinedOutput(); err != nil {
1350					t.Fatalf("%v: %v\n%s", cmd, err, out)
1351				}
1352			} else {
1353				if err := os.Symlink(target, link); err != nil {
1354					t.Fatalf("Symlink(%#q, %#q): %v", target, link, err)
1355				}
1356			}
1357			got, err := os.Readlink(link)
1358			if err != nil {
1359				t.Fatal(err)
1360			}
1361			if got != want {
1362				t.Fatalf("Readlink(%#q) = %#q; want %#q", target, got, want)
1363			}
1364		})
1365	}
1366}
1367
1368func TestOpenDirTOCTOU(t *testing.T) {
1369	t.Parallel()
1370
1371	// Check opened directories can't be renamed until the handle is closed.
1372	// See issue 52747.
1373	tmpdir := t.TempDir()
1374	dir := filepath.Join(tmpdir, "dir")
1375	if err := os.Mkdir(dir, 0777); err != nil {
1376		t.Fatal(err)
1377	}
1378	f, err := os.Open(dir)
1379	if err != nil {
1380		t.Fatal(err)
1381	}
1382	newpath := filepath.Join(tmpdir, "dir1")
1383	err = os.Rename(dir, newpath)
1384	if err == nil || !errors.Is(err, windows.ERROR_SHARING_VIOLATION) {
1385		f.Close()
1386		t.Fatalf("Rename(%q, %q) = %v; want windows.ERROR_SHARING_VIOLATION", dir, newpath, err)
1387	}
1388	f.Close()
1389	err = os.Rename(dir, newpath)
1390	if err != nil {
1391		t.Error(err)
1392	}
1393}
1394
1395func TestAppExecLinkStat(t *testing.T) {
1396	// We expect executables installed to %LOCALAPPDATA%\Microsoft\WindowsApps to
1397	// be reparse points with tag IO_REPARSE_TAG_APPEXECLINK. Here we check that
1398	// such reparse points are treated as irregular (but executable) files, not
1399	// broken symlinks.
1400	appdata := os.Getenv("LOCALAPPDATA")
1401	if appdata == "" {
1402		t.Skipf("skipping: LOCALAPPDATA not set")
1403	}
1404
1405	pythonExeName := "python3.exe"
1406	pythonPath := filepath.Join(appdata, `Microsoft\WindowsApps`, pythonExeName)
1407
1408	lfi, err := os.Lstat(pythonPath)
1409	if err != nil {
1410		t.Skip("skipping test, because Python 3 is not installed via the Windows App Store on this system; see https://golang.org/issue/42919")
1411	}
1412
1413	// An APPEXECLINK reparse point is not a symlink, so os.Readlink should return
1414	// a non-nil error for it, and Stat should return results identical to Lstat.
1415	linkName, err := os.Readlink(pythonPath)
1416	if err == nil {
1417		t.Errorf("os.Readlink(%q) = %q, but expected an error\n(should be an APPEXECLINK reparse point, not a symlink)", pythonPath, linkName)
1418	}
1419
1420	sfi, err := os.Stat(pythonPath)
1421	if err != nil {
1422		t.Fatalf("Stat %s: %v", pythonPath, err)
1423	}
1424
1425	if lfi.Name() != sfi.Name() {
1426		t.Logf("os.Lstat(%q) = %+v", pythonPath, lfi)
1427		t.Logf("os.Stat(%q)  = %+v", pythonPath, sfi)
1428		t.Errorf("files should be same")
1429	}
1430
1431	if lfi.Name() != pythonExeName {
1432		t.Errorf("Stat %s: got %q, but wanted %q", pythonPath, lfi.Name(), pythonExeName)
1433	}
1434	if tp := lfi.Mode().Type(); tp != fs.ModeIrregular {
1435		// A reparse point is not a regular file, but we don't have a more appropriate
1436		// ModeType bit for it, so it should be marked as irregular.
1437		t.Errorf("%q should not be a an irregular file (mode=0x%x)", pythonPath, uint32(tp))
1438	}
1439
1440	if sfi.Name() != pythonExeName {
1441		t.Errorf("Stat %s: got %q, but wanted %q", pythonPath, sfi.Name(), pythonExeName)
1442	}
1443	if m := sfi.Mode(); m&fs.ModeSymlink != 0 {
1444		t.Errorf("%q should be a file, not a link (mode=0x%x)", pythonPath, uint32(m))
1445	}
1446	if m := sfi.Mode(); m&fs.ModeDir != 0 {
1447		t.Errorf("%q should be a file, not a directory (mode=0x%x)", pythonPath, uint32(m))
1448	}
1449	if m := sfi.Mode(); m&fs.ModeIrregular == 0 {
1450		// A reparse point is not a regular file, but we don't have a more appropriate
1451		// ModeType bit for it, so it should be marked as irregular.
1452		t.Errorf("%q should not be a regular file (mode=0x%x)", pythonPath, uint32(m))
1453	}
1454
1455	p, err := exec.LookPath(pythonPath)
1456	if err != nil {
1457		t.Errorf("exec.LookPath(%q): %v", pythonPath, err)
1458	}
1459	if p != pythonPath {
1460		t.Errorf("exec.LookPath(%q) = %q; want %q", pythonPath, p, pythonPath)
1461	}
1462}
1463
1464func TestIllformedUTF16FileName(t *testing.T) {
1465	dir := t.TempDir()
1466	const sep = string(os.PathSeparator)
1467	if !strings.HasSuffix(dir, sep) {
1468		dir += sep
1469	}
1470
1471	// This UTF-16 file name is ill-formed as it contains low surrogates that are not preceded by high surrogates ([1:5]).
1472	namew := []uint16{0x2e, 0xdc6d, 0xdc73, 0xdc79, 0xdc73, 0x30, 0x30, 0x30, 0x31, 0}
1473
1474	// Create a file whose name contains unpaired surrogates.
1475	// Use syscall.CreateFile instead of os.Create to simulate a file that is created by
1476	// a non-Go program so the file name hasn't gone through syscall.UTF16FromString.
1477	dirw := utf16.Encode([]rune(dir))
1478	pathw := append(dirw, namew...)
1479	fd, err := syscall.CreateFile(&pathw[0], syscall.GENERIC_ALL, 0, nil, syscall.CREATE_NEW, 0, 0)
1480	if err != nil {
1481		t.Fatal(err)
1482	}
1483	syscall.CloseHandle(fd)
1484
1485	name := syscall.UTF16ToString(namew)
1486	path := filepath.Join(dir, name)
1487	// Verify that os.Lstat can query the file.
1488	fi, err := os.Lstat(path)
1489	if err != nil {
1490		t.Fatal(err)
1491	}
1492	if got := fi.Name(); got != name {
1493		t.Errorf("got %q, want %q", got, name)
1494	}
1495	// Verify that File.Readdirnames lists the file.
1496	f, err := os.Open(dir)
1497	if err != nil {
1498		t.Fatal(err)
1499	}
1500	files, err := f.Readdirnames(0)
1501	f.Close()
1502	if err != nil {
1503		t.Fatal(err)
1504	}
1505	if !slices.Contains(files, name) {
1506		t.Error("file not listed")
1507	}
1508	// Verify that os.RemoveAll can remove the directory
1509	// and that it doesn't hang.
1510	err = os.RemoveAll(dir)
1511	if err != nil {
1512		t.Error(err)
1513	}
1514}
1515
1516func TestUTF16Alloc(t *testing.T) {
1517	allowsPerRun := func(want int, f func()) {
1518		t.Helper()
1519		got := int(testing.AllocsPerRun(5, f))
1520		if got != want {
1521			t.Errorf("got %d allocs, want %d", got, want)
1522		}
1523	}
1524	allowsPerRun(1, func() {
1525		syscall.UTF16ToString([]uint16{'a', 'b', 'c'})
1526	})
1527	allowsPerRun(1, func() {
1528		syscall.UTF16FromString("abc")
1529	})
1530}
1531
1532func TestNewFileInvalid(t *testing.T) {
1533	t.Parallel()
1534	if f := os.NewFile(uintptr(syscall.InvalidHandle), "invalid"); f != nil {
1535		t.Errorf("NewFile(InvalidHandle) got %v want nil", f)
1536	}
1537}
1538
1539func TestReadDirPipe(t *testing.T) {
1540	dir := `\\.\pipe\`
1541	fi, err := os.Stat(dir)
1542	if err != nil || !fi.IsDir() {
1543		t.Skipf("%s is not a directory", dir)
1544	}
1545	_, err = os.ReadDir(dir)
1546	if err != nil {
1547		t.Errorf("ReadDir(%q) = %v", dir, err)
1548	}
1549}
1550
1551func TestReadDirNoFileID(t *testing.T) {
1552	*os.AllowReadDirFileID = false
1553	defer func() { *os.AllowReadDirFileID = true }()
1554
1555	dir := t.TempDir()
1556	pathA := filepath.Join(dir, "a")
1557	pathB := filepath.Join(dir, "b")
1558	if err := os.WriteFile(pathA, nil, 0666); err != nil {
1559		t.Fatal(err)
1560	}
1561	if err := os.WriteFile(pathB, nil, 0666); err != nil {
1562		t.Fatal(err)
1563	}
1564
1565	files, err := os.ReadDir(dir)
1566	if err != nil {
1567		t.Fatal(err)
1568	}
1569	if len(files) != 2 {
1570		t.Fatalf("ReadDir(%q) = %v; want 2 files", dir, files)
1571	}
1572
1573	// Check that os.SameFile works with files returned by os.ReadDir.
1574	f1, err := files[0].Info()
1575	if err != nil {
1576		t.Fatal(err)
1577	}
1578	f2, err := files[1].Info()
1579	if err != nil {
1580		t.Fatal(err)
1581	}
1582	if !os.SameFile(f1, f1) {
1583		t.Errorf("SameFile(%v, %v) = false; want true", f1, f1)
1584	}
1585	if !os.SameFile(f2, f2) {
1586		t.Errorf("SameFile(%v, %v) = false; want true", f2, f2)
1587	}
1588	if os.SameFile(f1, f2) {
1589		t.Errorf("SameFile(%v, %v) = true; want false", f1, f2)
1590	}
1591
1592	// Check that os.SameFile works with a mix of os.ReadDir and os.Stat files.
1593	f1s, err := os.Stat(pathA)
1594	if err != nil {
1595		t.Fatal(err)
1596	}
1597	f2s, err := os.Stat(pathB)
1598	if err != nil {
1599		t.Fatal(err)
1600	}
1601	if !os.SameFile(f1, f1s) {
1602		t.Errorf("SameFile(%v, %v) = false; want true", f1, f1s)
1603	}
1604	if !os.SameFile(f2, f2s) {
1605		t.Errorf("SameFile(%v, %v) = false; want true", f2, f2s)
1606	}
1607}
1608