case fs.ModeNamedPipe:
		m = s_IFIFO
	case fs.ModeSocket:
		m = s_IFSOCK
	case fs.ModeDevice:
		m = s_IFBLK
	case fs.ModeDevice | fs.ModeCharDevice:
		m = s_IFCHR
	}
	if mode&fs.ModeSetuid != 0 {
		m |= s_ISUID
	}
	if mode&fs.ModeSetgid != 0 {
		m |= s_ISGID
	}
	if mode&fs.ModeSticky != 0 {
		m |= s_ISVTX
	}
	return m | uint32(mode&0777)
}

// using the semantics of fs.FS.Open:
// paths are always slash separated, with no
// leading / or ../ elements.
func (r *Reader) Open(name string) (fs.File, error) {
	r.initFileList()

	if !fs.ValidPath(name) {
		return nil, &fs.PathError{Op: "open", Path: name, Err: fs.ErrInvalid}
	}
	e := r.openLookup(name)
	if e == nil {
		return nil, &fs.PathError{Op: "open", Path: name, Err: fs.ErrNotExist}
	}

// external zip tool is used or the ordering of file names in a directory
// or the current time.
package main

import (
	"archive/zip"
	"bytes"
	"flag"
	"fmt"
	"hash/crc32"
	"io/fs"
	"log"
	"os"
	"path/filepath"
	"strings"
)

func usage() {
	fmt.Fprintf(os.Stderr, "usage: go run mkzip.go zoneinfo.zip\n")
	os.Exit(2)
}

func main() {
	log.SetPrefix("mkzip: ")

	tw.pad = blockPadding(size)
	return nil
}

// AddFS adds the files from fs.FS to the archive.
// It walks the directory tree starting at the root of the filesystem
// adding each file to the tar archive while maintaining the directory structure.
func (tw *Writer) AddFS(fsys fs.FS) error {
	return fs.WalkDir(fsys, ".", func(name string, d fs.DirEntry, err error) error {
		if err != nil {
			return err
		}
		if d.IsDir() {

	switch m := fs.FileMode(fi.h.Mode) &^ 07777; m {
	case c_ISDIR:
		mode |= fs.ModeDir
	case c_ISFIFO:
		mode |= fs.ModeNamedPipe
	case c_ISLNK:
		mode |= fs.ModeSymlink
	case c_ISBLK:
		mode |= fs.ModeDevice
	case c_ISCHR:
		mode |= fs.ModeDevice
		mode |= fs.ModeCharDevice
	case c_ISSOCK:
		mode |= fs.ModeSocket
	}

	switch fi.h.Typeflag {
	case TypeSymlink:
		mode |= fs.ModeSymlink

			t.Errorf("Opening %q with fs.FS API succeeded", f.Name)
		}
	}
	if !reflect.DeepEqual(names, entryNames) {
		t.Errorf("Unexpected file entries: %q", names)
	}
	if _, err := r.Open(""); err == nil {
		t.Errorf("Opening %q with fs.FS API succeeded", "")
	}
	if _, err := r.Open("test.txt"); err != nil {
		t.Errorf("Error opening %q with fs.FS API: %v", "test.txt", err)
	}

	{
		Name:   "setuid",
		Data:   []byte("setuid file"),
		Method: Deflate,
		Mode:   0755 | fs.ModeSetuid,
	},
	{
		Name:   "setgid",
		Data:   []byte("setgid file"),
		Method: Deflate,
		Mode:   0755 | fs.ModeSetgid,
	},
	{
		Name:   "symlink",
		Data:   []byte("../link/target"),
		Method: Deflate,
		Mode:   0755 | fs.ModeSymlink,
	},
	{
		Name:   "device",
		Data:   []byte("device file"),

//go:build unix

package tar

import (
	"io/fs"
	"os/user"
	"runtime"
	"strconv"
	"sync"
	"syscall"
)

func init() {
	sysStat = statUnix
}

// userMap and groupMap caches UID and GID lookups for performance reasons.
// The downside is that renaming uname or gname by the OS never takes effect.
var userMap, groupMap sync.Map // map[int]string

func statUnix(fi fs.FileInfo, h *Header, doNameLookups bool) error {

func compareStatus(filter, expect string) error {
	expected := filter + expect
	pid := syscall.Getpid()
	fs, err := os.ReadDir(fmt.Sprintf("/proc/%d/task", pid))
	if err != nil {
		return fmt.Errorf("unable to find %d tasks: %v", pid, err)
	}
	expectedProc := fmt.Sprintf("Pid:\t%d", pid)
	foundAThread := false
	for _, f := range fs {
		tf := fmt.Sprintf("/proc/%s/status", f.Name())
		d, err := os.ReadFile(tf)
		if err != nil {

			ModTime:  time.Unix(1360600852, 0),
			Typeflag: TypeSymlink,
		},
		fm: 0777 | fs.ModeSymlink,
	}, {
		// character device node.
		h: &Header{
			Name:     "dev/null",
			Mode:     0666,
			Size:     0,
			ModTime:  time.Unix(1360578951, 0),
			Typeflag: TypeChar,
		},
		fm: 0666 | fs.ModeDevice | fs.ModeCharDevice,
	}, {
		// block device node.
		h: &Header{
			Name:     "dev/sda",