Lib/test/test_tarfile.py

import sys
import os
import io
from hashlib import md5
from contextlib import contextmanager
from random import Random
import pathlib

import unittest
import unittest.mock
import tarfile

from test import support
from test.support import script_helper

# Check for our compression modules.
try:
    import gzip
except ImportError:
    gzip = None
try:
    import bz2
except ImportError:
    bz2 = None
try:
    import lzma
except ImportError:
    lzma = None

def md5sum(data):
    return md5(data).hexdigest()

TEMPDIR = os.path.abspath(support.TESTFN) + "-tardir"
tarextdir = TEMPDIR + '-extract-test'
tarname = support.findfile("testtar.tar")
gzipname = os.path.join(TEMPDIR, "testtar.tar.gz")
bz2name = os.path.join(TEMPDIR, "testtar.tar.bz2")
xzname = os.path.join(TEMPDIR, "testtar.tar.xz")
tmpname = os.path.join(TEMPDIR, "tmp.tar")
dotlessname = os.path.join(TEMPDIR, "testtar")

md5_regtype = "65f477c818ad9e15f7feab0c6d37742f"
md5_sparse = "a54fbc4ca4f4399a90e1b27164012fc6"


class TarTest:
    tarname = tarname
    suffix = ''
    open = io.FileIO
    taropen = tarfile.TarFile.taropen

    @property
    def mode(self):
        return self.prefix + self.suffix

@support.requires_gzip
class GzipTest:
    tarname = gzipname
    suffix = 'gz'
    open = gzip.GzipFile if gzip else None
    taropen = tarfile.TarFile.gzopen

@support.requires_bz2
class Bz2Test:
    tarname = bz2name
    suffix = 'bz2'
    open = bz2.BZ2File if bz2 else None
    taropen = tarfile.TarFile.bz2open

@support.requires_lzma
class LzmaTest:
    tarname = xzname
    suffix = 'xz'
    open = lzma.LZMAFile if lzma else None
    taropen = tarfile.TarFile.xzopen


class ReadTest(TarTest):

    prefix = "r:"

    def setUp(self):
        self.tar = tarfile.open(self.tarname, mode=self.mode,
                                encoding="iso8859-1")

    def tearDown(self):
        self.tar.close()


class UstarReadTest(ReadTest, unittest.TestCase):

    def test_fileobj_regular_file(self):
        tarinfo = self.tar.getmember("ustar/regtype")
        with self.tar.extractfile(tarinfo) as fobj:
            data = fobj.read()
            self.assertEqual(len(data), tarinfo.size,
                    "regular file extraction failed")
            self.assertEqual(md5sum(data), md5_regtype,
                    "regular file extraction failed")

    def test_fileobj_readlines(self):
        self.tar.extract("ustar/regtype", TEMPDIR)
        tarinfo = self.tar.getmember("ustar/regtype")
        with open(os.path.join(TEMPDIR, "ustar/regtype"), "r") as fobj1:
            lines1 = fobj1.readlines()

        with self.tar.extractfile(tarinfo) as fobj:
            fobj2 = io.TextIOWrapper(fobj)
            lines2 = fobj2.readlines()
            self.assertEqual(lines1, lines2,
                    "fileobj.readlines() failed")
            self.assertEqual(len(lines2), 114,
                    "fileobj.readlines() failed")
            self.assertEqual(lines2[83],
                    "I will gladly admit that Python is not the fastest "
                    "running scripting language.\n",
                    "fileobj.readlines() failed")

    def test_fileobj_iter(self):
        self.tar.extract("ustar/regtype", TEMPDIR)
        tarinfo = self.tar.getmember("ustar/regtype")
        with open(os.path.join(TEMPDIR, "ustar/regtype"), "r") as fobj1:
            lines1 = fobj1.readlines()
        with self.tar.extractfile(tarinfo) as fobj2:
            lines2 = list(io.TextIOWrapper(fobj2))
            self.assertEqual(lines1, lines2,
                    "fileobj.__iter__() failed")

    def test_fileobj_seek(self):
        self.tar.extract("ustar/regtype", TEMPDIR)
        with open(os.path.join(TEMPDIR, "ustar/regtype"), "rb") as fobj:
            data = fobj.read()

        tarinfo = self.tar.getmember("ustar/regtype")
        fobj = self.tar.extractfile(tarinfo)

        text = fobj.read()
        fobj.seek(0)
        self.assertEqual(0, fobj.tell(),
                     "seek() to file's start failed")
        fobj.seek(2048, 0)
        self.assertEqual(2048, fobj.tell(),
                     "seek() to absolute position failed")
        fobj.seek(-1024, 1)
        self.assertEqual(1024, fobj.tell(),
                     "seek() to negative relative position failed")
        fobj.seek(1024, 1)
        self.assertEqual(2048, fobj.tell(),
                     "seek() to positive relative position failed")
        s = fobj.read(10)
        self.assertEqual(s, data[2048:2058],
                     "read() after seek failed")
        fobj.seek(0, 2)
        self.assertEqual(tarinfo.size, fobj.tell(),
                     "seek() to file's end failed")
        self.assertEqual(fobj.read(), b"",
                     "read() at file's end did not return empty string")
        fobj.seek(-tarinfo.size, 2)
        self.assertEqual(0, fobj.tell(),
                     "relative seek() to file's end failed")
        fobj.seek(512)
        s1 = fobj.readlines()
        fobj.seek(512)
        s2 = fobj.readlines()
        self.assertEqual(s1, s2,
                     "readlines() after seek failed")
        fobj.seek(0)
        self.assertEqual(len(fobj.readline()), fobj.tell(),
                     "tell() after readline() failed")
        fobj.seek(512)
        self.assertEqual(len(fobj.readline()) + 512, fobj.tell(),
                     "tell() after seek() and readline() failed")
        fobj.seek(0)
        line = fobj.readline()
        self.assertEqual(fobj.read(), data[len(line):],
                     "read() after readline() failed")
        fobj.close()

    def test_fileobj_text(self):
        with self.tar.extractfile("ustar/regtype") as fobj:
            fobj = io.TextIOWrapper(fobj)
            data = fobj.read().encode("iso8859-1")
            self.assertEqual(md5sum(data), md5_regtype)
            try:
                fobj.seek(100)
            except AttributeError:
                # Issue #13815: seek() complained about a missing
                # flush() method.
                self.fail("seeking failed in text mode")

    # Test if symbolic and hard links are resolved by extractfile().  The
    # test link members each point to a regular member whose data is
    # supposed to be exported.
    def _test_fileobj_link(self, lnktype, regtype):
        with self.tar.extractfile(lnktype) as a, \
             self.tar.extractfile(regtype) as b:
            self.assertEqual(a.name, b.name)

    def test_fileobj_link1(self):
        self._test_fileobj_link("ustar/lnktype", "ustar/regtype")

    def test_fileobj_link2(self):
        self._test_fileobj_link("./ustar/linktest2/lnktype",
                                "ustar/linktest1/regtype")

    def test_fileobj_symlink1(self):
        self._test_fileobj_link("ustar/symtype", "ustar/regtype")

    def test_fileobj_symlink2(self):
        self._test_fileobj_link("./ustar/linktest2/symtype",
                                "ustar/linktest1/regtype")

    def test_issue14160(self):
        self._test_fileobj_link("symtype2", "ustar/regtype")

class GzipUstarReadTest(GzipTest, UstarReadTest):
    pass

class Bz2UstarReadTest(Bz2Test, UstarReadTest):
    pass

class LzmaUstarReadTest(LzmaTest, UstarReadTest):
    pass


class ListTest(ReadTest, unittest.TestCase):

    # Override setUp to use default encoding (UTF-8)
    def setUp(self):
        self.tar = tarfile.open(self.tarname, mode=self.mode)

    def test_list(self):
        tio = io.TextIOWrapper(io.BytesIO(), 'ascii', newline='\n')
        with support.swap_attr(sys, 'stdout', tio):
            self.tar.list(verbose=False)
        out = tio.detach().getvalue()
        self.assertIn(b'ustar/conttype', out)
        self.assertIn(b'ustar/regtype', out)
        self.assertIn(b'ustar/lnktype', out)
        self.assertIn(b'ustar' + (b'/12345' * 40) + b'67/longname', out)
        self.assertIn(b'./ustar/linktest2/symtype', out)
        self.assertIn(b'./ustar/linktest2/lnktype', out)
        # Make sure it puts trailing slash for directory
        self.assertIn(b'ustar/dirtype/', out)
        self.assertIn(b'ustar/dirtype-with-size/', out)
        # Make sure it is able to print unencodable characters
        def conv(b):
            s = b.decode(self.tar.encoding, 'surrogateescape')
            return s.encode('ascii', 'backslashreplace')
        self.assertIn(conv(b'ustar/umlauts-\xc4\xd6\xdc\xe4\xf6\xfc\xdf'), out)
        self.assertIn(conv(b'misc/regtype-hpux-signed-chksum-'
                           b'\xc4\xd6\xdc\xe4\xf6\xfc\xdf'), out)
        self.assertIn(conv(b'misc/regtype-old-v7-signed-chksum-'
                           b'\xc4\xd6\xdc\xe4\xf6\xfc\xdf'), out)
        self.assertIn(conv(b'pax/bad-pax-\xe4\xf6\xfc'), out)
        self.assertIn(conv(b'pax/hdrcharset-\xe4\xf6\xfc'), out)
        # Make sure it prints files separated by one newline without any
        # 'ls -l'-like accessories if verbose flag is not being used
        # ...
        # ustar/conttype
        # ustar/regtype
        # ...
        self.assertRegex(out, br'ustar/conttype ?\r?\n'
                              br'ustar/regtype ?\r?\n')
        # Make sure it does not print the source of link without verbose flag
        self.assertNotIn(b'link to', out)
        self.assertNotIn(b'->', out)

    def test_list_verbose(self):
        tio = io.TextIOWrapper(io.BytesIO(), 'ascii', newline='\n')
        with support.swap_attr(sys, 'stdout', tio):
            self.tar.list(verbose=True)
        out = tio.detach().getvalue()
        # Make sure it prints files separated by one newline with 'ls -l'-like
        # accessories if verbose flag is being used
        # ...
        # ?rw-r--r-- tarfile/tarfile     7011 2003-01-06 07:19:43 ustar/conttype
        # ?rw-r--r-- tarfile/tarfile     7011 2003-01-06 07:19:43 ustar/regtype
        # ...
        self.assertRegex(out, (br'\?rw-r--r-- tarfile/tarfile\s+7011 '
                               br'\d{4}-\d\d-\d\d\s+\d\d:\d\d:\d\d '
                               br'ustar/\w+type ?\r?\n') * 2)
        # Make sure it prints the source of link with verbose flag
        self.assertIn(b'ustar/symtype -> regtype', out)
        self.assertIn(b'./ustar/linktest2/symtype -> ../linktest1/regtype', out)
        self.assertIn(b'./ustar/linktest2/lnktype link to '
                      b'./ustar/linktest1/regtype', out)
        self.assertIn(b'gnu' + (b'/123' * 125) + b'/longlink link to gnu' +
                      (b'/123' * 125) + b'/longname', out)
        self.assertIn(b'pax' + (b'/123' * 125) + b'/longlink link to pax' +
                      (b'/123' * 125) + b'/longname', out)

    def test_list_members(self):
        tio = io.TextIOWrapper(io.BytesIO(), 'ascii', newline='\n')
        def members(tar):
            for tarinfo in tar.getmembers():
                if 'reg' in tarinfo.name:
                    yield tarinfo
        with support.swap_attr(sys, 'stdout', tio):
            self.tar.list(verbose=False, members=members(self.tar))
        out = tio.detach().getvalue()
        self.assertIn(b'ustar/regtype', out)
        self.assertNotIn(b'ustar/conttype', out)


class GzipListTest(GzipTest, ListTest):
    pass


class Bz2ListTest(Bz2Test, ListTest):
    pass


class LzmaListTest(LzmaTest, ListTest):
    pass


class CommonReadTest(ReadTest):

    def test_empty_tarfile(self):
        # Test for issue6123: Allow opening empty archives.
        # This test checks if tarfile.open() is able to open an empty tar
        # archive successfully. Note that an empty tar archive is not the
        # same as an empty file!
        with tarfile.open(tmpname, self.mode.replace("r", "w")):
            pass
        try:
            tar = tarfile.open(tmpname, self.mode)
            tar.getnames()
        except tarfile.ReadError:
            self.fail("tarfile.open() failed on empty archive")
        else:
            self.assertListEqual(tar.getmembers(), [])
        finally:
            tar.close()

    def test_non_existent_tarfile(self):
        # Test for issue11513: prevent non-existent gzipped tarfiles raising
        # multiple exceptions.
        with self.assertRaisesRegex(FileNotFoundError, "xxx"):
            tarfile.open("xxx", self.mode)

    def test_null_tarfile(self):
        # Test for issue6123: Allow opening empty archives.
        # This test guarantees that tarfile.open() does not treat an empty
        # file as an empty tar archive.
        with open(tmpname, "wb"):
            pass
        self.assertRaises(tarfile.ReadError, tarfile.open, tmpname, self.mode)
        self.assertRaises(tarfile.ReadError, tarfile.open, tmpname)

    def test_ignore_zeros(self):
        # Test TarFile's ignore_zeros option.
        # generate 512 pseudorandom bytes
        data = Random(0).getrandbits(512*8).to_bytes(512, 'big')
        for char in (b'\0', b'a'):
            # Test if EOFHeaderError ('\0') and InvalidHeaderError ('a')
            # are ignored correctly.
            with self.open(tmpname, "w") as fobj:
                fobj.write(char * 1024)
                tarinfo = tarfile.TarInfo("foo")
                tarinfo.size = len(data)
                fobj.write(tarinfo.tobuf())
                fobj.write(data)

            tar = tarfile.open(tmpname, mode="r", ignore_zeros=True)
            try:
                self.assertListEqual(tar.getnames(), ["foo"],
                    "ignore_zeros=True should have skipped the %r-blocks" %
                    char)
            finally:
                tar.close()

    def test_premature_end_of_archive(self):
        for size in (512, 600, 1024, 1200):
            with tarfile.open(tmpname, "w:") as tar:
                t = tarfile.TarInfo("foo")
                t.size = 1024
                tar.addfile(t, io.BytesIO(b"a" * 1024))

            with open(tmpname, "r+b") as fobj:
                fobj.truncate(size)

            with tarfile.open(tmpname) as tar:
                with self.assertRaisesRegex(tarfile.ReadError, "unexpected end of data"):
                    for t in tar:
                        pass

            with tarfile.open(tmpname) as tar:
                t = tar.next()

                with self.assertRaisesRegex(tarfile.ReadError, "unexpected end of data"):
                    tar.extract(t, TEMPDIR)

                with self.assertRaisesRegex(tarfile.ReadError, "unexpected end of data"):
                    tar.extractfile(t).read()

class MiscReadTestBase(CommonReadTest):
    def requires_name_attribute(self):
        pass

    def test_no_name_argument(self):
        self.requires_name_attribute()
        with open(self.tarname, "rb") as fobj:
            self.assertIsInstance(fobj.name, str)
            with tarfile.open(fileobj=fobj, mode=self.mode) as tar:
                self.assertIsInstance(tar.name, str)
                self.assertEqual(tar.name, os.path.abspath(fobj.name))

    def test_no_name_attribute(self):
        with open(self.tarname, "rb") as fobj:
            data = fobj.read()
        fobj = io.BytesIO(data)
        self.assertRaises(AttributeError, getattr, fobj, "name")
        tar = tarfile.open(fileobj=fobj, mode=self.mode)
        self.assertIsNone(tar.name)

    def test_empty_name_attribute(self):
        with open(self.tarname, "rb") as fobj:
            data = fobj.read()
        fobj = io.BytesIO(data)
        fobj.name = ""
        with tarfile.open(fileobj=fobj, mode=self.mode) as tar:
            self.assertIsNone(tar.name)

    def test_int_name_attribute(self):
        # Issue 21044: tarfile.open() should handle fileobj with an integer
        # 'name' attribute.
        fd = os.open(self.tarname, os.O_RDONLY)
        with open(fd, 'rb') as fobj:
            self.assertIsInstance(fobj.name, int)
            with tarfile.open(fileobj=fobj, mode=self.mode) as tar:
                self.assertIsNone(tar.name)

    def test_bytes_name_attribute(self):
        self.requires_name_attribute()
        tarname = os.fsencode(self.tarname)
        with open(tarname, 'rb') as fobj:
            self.assertIsInstance(fobj.name, bytes)
            with tarfile.open(fileobj=fobj, mode=self.mode) as tar:
                self.assertIsInstance(tar.name, bytes)
                self.assertEqual(tar.name, os.path.abspath(fobj.name))

    def test_pathlike_name(self):
        tarname = pathlib.Path(self.tarname)
        with tarfile.open(tarname, mode=self.mode) as tar:
            self.assertIsInstance(tar.name, str)
            self.assertEqual(tar.name, os.path.abspath(os.fspath(tarname)))
        with self.taropen(tarname) as tar:
            self.assertIsInstance(tar.name, str)
            self.assertEqual(tar.name, os.path.abspath(os.fspath(tarname)))
        with tarfile.TarFile.open(tarname, mode=self.mode) as tar:
            self.assertIsInstance(tar.name, str)
            self.assertEqual(tar.name, os.path.abspath(os.fspath(tarname)))
        if self.suffix == '':
            with tarfile.TarFile(tarname, mode='r') as tar:
                self.assertIsInstance(tar.name, str)
                self.assertEqual(tar.name, os.path.abspath(os.fspath(tarname)))

    def test_illegal_mode_arg(self):
        with open(tmpname, 'wb'):
            pass
        with self.assertRaisesRegex(ValueError, 'mode must be '):
            tar = self.taropen(tmpname, 'q')
        with self.assertRaisesRegex(ValueError, 'mode must be '):
            tar = self.taropen(tmpname, 'rw')
        with self.assertRaisesRegex(ValueError, 'mode must be '):
            tar = self.taropen(tmpname, '')

    def test_fileobj_with_offset(self):
        # Skip the first member and store values from the second member
        # of the testtar.
        tar = tarfile.open(self.tarname, mode=self.mode)
        try:
            tar.next()
            t = tar.next()
            name = t.name
            offset = t.offset
            with tar.extractfile(t) as f:
                data = f.read()
        finally:
            tar.close()

        # Open the testtar and seek to the offset of the second member.
        with self.open(self.tarname) as fobj:
            fobj.seek(offset)

            # Test if the tarfile starts with the second member.
            tar = tar.open(self.tarname, mode="r:", fileobj=fobj)
            t = tar.next()
            self.assertEqual(t.name, name)
            # Read to the end of fileobj and test if seeking back to the
            # beginning works.
            tar.getmembers()
            self.assertEqual(tar.extractfile(t).read(), data,
                    "seek back did not work")
            tar.close()

    def test_fail_comp(self):
        # For Gzip and Bz2 Tests: fail with a ReadError on an uncompressed file.
        self.assertRaises(tarfile.ReadError, tarfile.open, tarname, self.mode)
        with open(tarname, "rb") as fobj:
            self.assertRaises(tarfile.ReadError, tarfile.open,
                              fileobj=fobj, mode=self.mode)

    def test_v7_dirtype(self):
        # Test old style dirtype member (bug #1336623):
        # Old V7 tars create directory members using an AREGTYPE
        # header with a "/" appended to the filename field.
        tarinfo = self.tar.getmember("misc/dirtype-old-v7")
        self.assertEqual(tarinfo.type, tarfile.DIRTYPE,
                "v7 dirtype failed")

    def test_xstar_type(self):
        # The xstar format stores extra atime and ctime fields inside the
        # space reserved for the prefix field. The prefix field must be
        # ignored in this case, otherwise it will mess up the name.
        try:
            self.tar.getmember("misc/regtype-xstar")
        except KeyError:
            self.fail("failed to find misc/regtype-xstar (mangled prefix?)")

    def test_check_members(self):
        for tarinfo in self.tar:
            self.assertEqual(int(tarinfo.mtime), 0o7606136617,
                    "wrong mtime for %s" % tarinfo.name)
            if not tarinfo.name.startswith("ustar/"):
                continue
            self.assertEqual(tarinfo.uname, "tarfile",
                    "wrong uname for %s" % tarinfo.name)

    def test_find_members(self):
        self.assertEqual(self.tar.getmembers()[-1].name, "misc/eof",
                "could not find all members")

    @unittest.skipUnless(hasattr(os, "link"),
                         "Missing hardlink implementation")
    @support.skip_unless_symlink
    def test_extract_hardlink(self):
        # Test hardlink extraction (e.g. bug #857297).
        with tarfile.open(tarname, errorlevel=1, encoding="iso8859-1") as tar:
            tar.extract("ustar/regtype", TEMPDIR)
            self.addCleanup(support.unlink, os.path.join(TEMPDIR, "ustar/regtype"))

            tar.extract("ustar/lnktype", TEMPDIR)
            self.addCleanup(support.unlink, os.path.join(TEMPDIR, "ustar/lnktype"))
            with open(os.path.join(TEMPDIR, "ustar/lnktype"), "rb") as f:
                data = f.read()
            self.assertEqual(md5sum(data), md5_regtype)

            tar.extract("ustar/symtype", TEMPDIR)
            self.addCleanup(support.unlink, os.path.join(TEMPDIR, "ustar/symtype"))
            with open(os.path.join(TEMPDIR, "ustar/symtype"), "rb") as f:
                data = f.read()
            self.assertEqual(md5sum(data), md5_regtype)

    def test_extractall(self):
        # Test if extractall() correctly restores directory permissions
        # and times (see issue1735).
        tar = tarfile.open(tarname, encoding="iso8859-1")
        DIR = os.path.join(TEMPDIR, "extractall")
        os.mkdir(DIR)
        try:
            directories = [t for t in tar if t.isdir()]
            tar.extractall(DIR, directories)
            for tarinfo in directories:
                path = os.path.join(DIR, tarinfo.name)
                if sys.platform != "win32":
                    # Win32 has no support for fine grained permissions.
                    self.assertEqual(tarinfo.mode & 0o777,
                                     os.stat(path).st_mode & 0o777)
                def format_mtime(mtime):
                    if isinstance(mtime, float):
                        return "{} ({})".format(mtime, mtime.hex())
                    else:
                        return "{!r} (int)".format(mtime)
                file_mtime = os.path.getmtime(path)
                errmsg = "tar mtime {0} != file time {1} of path {2!a}".format(
                    format_mtime(tarinfo.mtime),
                    format_mtime(file_mtime),
                    path)
                self.assertEqual(tarinfo.mtime, file_mtime, errmsg)
        finally:
            tar.close()
            support.rmtree(DIR)

    def test_extract_directory(self):
        dirtype = "ustar/dirtype"
        DIR = os.path.join(TEMPDIR, "extractdir")
        os.mkdir(DIR)
        try:
            with tarfile.open(tarname, encoding="iso8859-1") as tar:
                tarinfo = tar.getmember(dirtype)
                tar.extract(tarinfo, path=DIR)
                extracted = os.path.join(DIR, dirtype)
                self.assertEqual(os.path.getmtime(extracted), tarinfo.mtime)
                if sys.platform != "win32":
                    self.assertEqual(os.stat(extracted).st_mode & 0o777, 0o755)
        finally:
            support.rmtree(DIR)

    def test_extractall_pathlike_name(self):
        DIR = pathlib.Path(TEMPDIR) / "extractall"
        with support.temp_dir(DIR), \
             tarfile.open(tarname, encoding="iso8859-1") as tar:
            directories = [t for t in tar if t.isdir()]
            tar.extractall(DIR, directories)
            for tarinfo in directories:
                path = DIR / tarinfo.name
                self.assertEqual(os.path.getmtime(path), tarinfo.mtime)

    def test_extract_pathlike_name(self):
        dirtype = "ustar/dirtype"
        DIR = pathlib.Path(TEMPDIR) / "extractall"
        with support.temp_dir(DIR), \
             tarfile.open(tarname, encoding="iso8859-1") as tar:
            tarinfo = tar.getmember(dirtype)
            tar.extract(tarinfo, path=DIR)
            extracted = DIR / dirtype
            self.assertEqual(os.path.getmtime(extracted), tarinfo.mtime)

    def test_init_close_fobj(self):
        # Issue #7341: Close the internal file object in the TarFile
        # constructor in case of an error. For the test we rely on
        # the fact that opening an empty file raises a ReadError.
        empty = os.path.join(TEMPDIR, "empty")
        with open(empty, "wb") as fobj:
            fobj.write(b"")

        try:
            tar = object.__new__(tarfile.TarFile)
            try:
                tar.__init__(empty)
            except tarfile.ReadError:
                self.assertTrue(tar.fileobj.closed)
            else:
                self.fail("ReadError not raised")
        finally:
            support.unlink(empty)

    def test_parallel_iteration(self):
        # Issue #16601: Restarting iteration over tarfile continued
        # from where it left off.
        with tarfile.open(self.tarname) as tar:
            for m1, m2 in zip(tar, tar):
                self.assertEqual(m1.offset, m2.offset)
                self.assertEqual(m1.get_info(), m2.get_info())

class MiscReadTest(MiscReadTestBase, unittest.TestCase):
    test_fail_comp = None

class GzipMiscReadTest(GzipTest, MiscReadTestBase, unittest.TestCase):
    pass

class Bz2MiscReadTest(Bz2Test, MiscReadTestBase, unittest.TestCase):
    def requires_name_attribute(self):
        self.skipTest("BZ2File have no name attribute")

class LzmaMiscReadTest(LzmaTest, MiscReadTestBase, unittest.TestCase):
    def requires_name_attribute(self):
        self.skipTest("LZMAFile have no name attribute")


class StreamReadTest(CommonReadTest, unittest.TestCase):

    prefix="r|"

    def test_read_through(self):
        # Issue #11224: A poorly designed _FileInFile.read() method
        # caused seeking errors with stream tar files.
        for tarinfo in self.tar:
            if not tarinfo.isreg():
                continue
            with self.tar.extractfile(tarinfo) as fobj:
                while True:
                    try:
                        buf = fobj.read(512)
                    except tarfile.StreamError:
                        self.fail("simple read-through using "
                                  "TarFile.extractfile() failed")
                    if not buf:
                        break

    def test_fileobj_regular_file(self):
        tarinfo = self.tar.next() # get "regtype" (can't use getmember)
        with self.tar.extractfile(tarinfo) as fobj:
            data = fobj.read()
        self.assertEqual(len(data), tarinfo.size,
                "regular file extraction failed")
        self.assertEqual(md5sum(data), md5_regtype,
                "regular file extraction failed")

    def test_provoke_stream_error(self):
        tarinfos = self.tar.getmembers()
        with self.tar.extractfile(tarinfos[0]) as f: # read the first member
            self.assertRaises(tarfile.StreamError, f.read)

    def test_compare_members(self):
        tar1 = tarfile.open(tarname, encoding="iso8859-1")
        try:
            tar2 = self.tar

            while True:
                t1 = tar1.next()
                t2 = tar2.next()
                if t1 is None:
                    break
                self.assertIsNotNone(t2, "stream.next() failed.")

                if t2.islnk() or t2.issym():
                    with self.assertRaises(tarfile.StreamError):
                        tar2.extractfile(t2)
                    continue

                v1 = tar1.extractfile(t1)
                v2 = tar2.extractfile(t2)
                if v1 is None:
                    continue
                self.assertIsNotNone(v2, "stream.extractfile() failed")
                self.assertEqual(v1.read(), v2.read(),
                        "stream extraction failed")
        finally:
            tar1.close()

class GzipStreamReadTest(GzipTest, StreamReadTest):
    pass

class Bz2StreamReadTest(Bz2Test, StreamReadTest):
    pass

class LzmaStreamReadTest(LzmaTest, StreamReadTest):
    pass


class DetectReadTest(TarTest, unittest.TestCase):
    def _testfunc_file(self, name, mode):
        try:
            tar = tarfile.open(name, mode)
        except tarfile.ReadError as e:
            self.fail()
        else:
            tar.close()

    def _testfunc_fileobj(self, name, mode):
        try:
            with open(name, "rb") as f:
                tar = tarfile.open(name, mode, fileobj=f)
        except tarfile.ReadError as e:
            self.fail()
        else:
            tar.close()

    def _test_modes(self, testfunc):
        if self.suffix:
            with self.assertRaises(tarfile.ReadError):
                tarfile.open(tarname, mode="r:" + self.suffix)
            with self.assertRaises(tarfile.ReadError):
                tarfile.open(tarname, mode="r|" + self.suffix)
            with self.assertRaises(tarfile.ReadError):
                tarfile.open(self.tarname, mode="r:")
            with self.assertRaises(tarfile.ReadError):
                tarfile.open(self.tarname, mode="r|")
        testfunc(self.tarname, "r")
        testfunc(self.tarname, "r:" + self.suffix)
        testfunc(self.tarname, "r:*")
        testfunc(self.tarname, "r|" + self.suffix)
        testfunc(self.tarname, "r|*")

    def test_detect_file(self):
        self._test_modes(self._testfunc_file)

    def test_detect_fileobj(self):
        self._test_modes(self._testfunc_fileobj)

class GzipDetectReadTest(GzipTest, DetectReadTest):
    pass

class Bz2DetectReadTest(Bz2Test, DetectReadTest):
    def test_detect_stream_bz2(self):
        # Originally, tarfile's stream detection looked for the string
        # "BZh91" at the start of the file. This is incorrect because
        # the '9' represents the blocksize (900kB). If the file was
        # compressed using another blocksize autodetection fails.
        with open(tarname, "rb") as fobj:
            data = fobj.read()

        # Compress with blocksize 100kB, the file starts with "BZh11".
        with bz2.BZ2File(tmpname, "wb", compresslevel=1) as fobj:
            fobj.write(data)

        self._testfunc_file(tmpname, "r|*")

class LzmaDetectReadTest(LzmaTest, DetectReadTest):
    pass


class MemberReadTest(ReadTest, unittest.TestCase):

    def _test_member(self, tarinfo, chksum=None, **kwargs):
        if chksum is not None:
            with self.tar.extractfile(tarinfo) as f:
                self.assertEqual(md5sum(f.read()), chksum,
                        "wrong md5sum for %s" % tarinfo.name)

        kwargs["mtime"] = 0o7606136617
        kwargs["uid"] = 1000
        kwargs["gid"] = 100
        if "old-v7" not in tarinfo.name:
            # V7 tar can't handle alphabetic owners.
            kwargs["uname"] = "tarfile"
            kwargs["gname"] = "tarfile"
        for k, v in kwargs.items():
            self.assertEqual(getattr(tarinfo, k), v,
                    "wrong value in %s field of %s" % (k, tarinfo.name))

    def test_find_regtype(self):
        tarinfo = self.tar.getmember("ustar/regtype")
        self._test_member(tarinfo, size=7011, chksum=md5_regtype)

    def test_find_conttype(self):
        tarinfo = self.tar.getmember("ustar/conttype")
        self._test_member(tarinfo, size=7011, chksum=md5_regtype)

    def test_find_dirtype(self):
        tarinfo = self.tar.getmember("ustar/dirtype")
        self._test_member(tarinfo, size=0)

    def test_find_dirtype_with_size(self):
        tarinfo = self.tar.getmember("ustar/dirtype-with-size")
        self._test_member(tarinfo, size=255)

    def test_find_lnktype(self):
        tarinfo = self.tar.getmember("ustar/lnktype")
        self._test_member(tarinfo, size=0, linkname="ustar/regtype")

    def test_find_symtype(self):
        tarinfo = self.tar.getmember("ustar/symtype")
        self._test_member(tarinfo, size=0, linkname="regtype")

    def test_find_blktype(self):
        tarinfo = self.tar.getmember("ustar/blktype")
        self._test_member(tarinfo, size=0, devmajor=3, devminor=0)

    def test_find_chrtype(self):
        tarinfo = self.tar.getmember("ustar/chrtype")
        self._test_member(tarinfo, size=0, devmajor=1, devminor=3)

    def test_find_fifotype(self):
        tarinfo = self.tar.getmember("ustar/fifotype")
        self._test_member(tarinfo, size=0)

    def test_find_sparse(self):
        tarinfo = self.tar.getmember("ustar/sparse")
        self._test_member(tarinfo, size=86016, chksum=md5_sparse)

    def test_find_gnusparse(self):
        tarinfo = self.tar.getmember("gnu/sparse")
        self._test_member(tarinfo, size=86016, chksum=md5_sparse)

    def test_find_gnusparse_00(self):
        tarinfo = self.tar.getmember("gnu/sparse-0.0")
        self._test_member(tarinfo, size=86016, chksum=md5_sparse)

    def test_find_gnusparse_01(self):
        tarinfo = self.tar.getmember("gnu/sparse-0.1")
        self._test_member(tarinfo, size=86016, chksum=md5_sparse)

    def test_find_gnusparse_10(self):
        tarinfo = self.tar.getmember("gnu/sparse-1.0")
        self._test_member(tarinfo, size=86016, chksum=md5_sparse)

    def test_find_umlauts(self):
        tarinfo = self.tar.getmember("ustar/umlauts-"
                                     "\xc4\xd6\xdc\xe4\xf6\xfc\xdf")
        self._test_member(tarinfo, size=7011, chksum=md5_regtype)

    def test_find_ustar_longname(self):
        name = "ustar/" + "12345/" * 39 + "1234567/longname"
        self.assertIn(name, self.tar.getnames())

    def test_find_regtype_oldv7(self):
        tarinfo = self.tar.getmember("misc/regtype-old-v7")
        self._test_member(tarinfo, size=7011, chksum=md5_regtype)

    def test_find_pax_umlauts(self):
        self.tar.close()
        self.tar = tarfile.open(self.tarname, mode=self.mode,
                                encoding="iso8859-1")
        tarinfo = self.tar.getmember("pax/umlauts-"
                                     "\xc4\xd6\xdc\xe4\xf6\xfc\xdf")
        self._test_member(tarinfo, size=7011, chksum=md5_regtype)


class LongnameTest:

    def test_read_longname(self):
        # Test reading of longname (bug #1471427).
        longname = self.subdir + "/" + "123/" * 125 + "longname"
        try:
            tarinfo = self.tar.getmember(longname)
        except KeyError:
            self.fail("longname not found")
        self.assertNotEqual(tarinfo.type, tarfile.DIRTYPE,
                "read longname as dirtype")

    def test_read_longlink(self):
        longname = self.subdir + "/" + "123/" * 125 + "longname"
        longlink = self.subdir + "/" + "123/" * 125 + "longlink"
        try:
            tarinfo = self.tar.getmember(longlink)
        except KeyError:
            self.fail("longlink not found")
        self.assertEqual(tarinfo.linkname, longname, "linkname wrong")

    def test_truncated_longname(self):
        longname = self.subdir + "/" + "123/" * 125 + "longname"
        tarinfo = self.tar.getmember(longname)
        offset = tarinfo.offset
        self.tar.fileobj.seek(offset)
        fobj = io.BytesIO(self.tar.fileobj.read(3 * 512))
        with self.assertRaises(tarfile.ReadError):
            tarfile.open(name="foo.tar", fileobj=fobj)

    def test_header_offset(self):
        # Test if the start offset of the TarInfo object includes
        # the preceding extended header.
        longname = self.subdir + "/" + "123/" * 125 + "longname"
        offset = self.tar.getmember(longname).offset
        with open(tarname, "rb") as fobj:
            fobj.seek(offset)
            tarinfo = tarfile.TarInfo.frombuf(fobj.read(512),
                                              "iso8859-1", "strict")
            self.assertEqual(tarinfo.type, self.longnametype)


class GNUReadTest(LongnameTest, ReadTest, unittest.TestCase):

    subdir = "gnu"
    longnametype = tarfile.GNUTYPE_LONGNAME

    # Since 3.2 tarfile is supposed to accurately restore sparse members and
    # produce files with holes. This is what we actually want to test here.
    # Unfortunately, not all platforms/filesystems support sparse files, and
    # even on platforms that do it is non-trivial to make reliable assertions
    # about holes in files. Therefore, we first do one basic test which works
    # an all platforms, and after that a test that will work only on
    # platforms/filesystems that prove to support sparse files.
    def _test_sparse_file(self, name):
        self.tar.extract(name, TEMPDIR)
        filename = os.path.join(TEMPDIR, name)
        with open(filename, "rb") as fobj:
            data = fobj.read()
        self.assertEqual(md5sum(data), md5_sparse,
                "wrong md5sum for %s" % name)

        if self._fs_supports_holes():
            s = os.stat(filename)
            self.assertLess(s.st_blocks * 512, s.st_size)

    def test_sparse_file_old(self):
        self._test_sparse_file("gnu/sparse")

    def test_sparse_file_00(self):
        self._test_sparse_file("gnu/sparse-0.0")

    def test_sparse_file_01(self):
        self._test_sparse_file("gnu/sparse-0.1")

    def test_sparse_file_10(self):
        self._test_sparse_file("gnu/sparse-1.0")

    @staticmethod
    def _fs_supports_holes():
        # Return True if the platform knows the st_blocks stat attribute and
        # uses st_blocks units of 512 bytes, and if the filesystem is able to
        # store holes in files.
        if sys.platform.startswith("linux"):
            # Linux evidentially has 512 byte st_blocks units.
            name = os.path.join(TEMPDIR, "sparse-test")
            with open(name, "wb") as fobj:
                fobj.seek(4096)
                fobj.truncate()
            s = os.stat(name)
            support.unlink(name)
            return s.st_blocks == 0
        else:
            return False


class PaxReadTest(LongnameTest, ReadTest, unittest.TestCase):

    subdir = "pax"
    longnametype = tarfile.XHDTYPE

    def test_pax_global_headers(self):
        tar = tarfile.open(tarname, encoding="iso8859-1")
        try:
            tarinfo = tar.getmember("pax/regtype1")
            self.assertEqual(tarinfo.uname, "foo")
            self.assertEqual(tarinfo.gname, "bar")
            self.assertEqual(tarinfo.pax_headers.get("VENDOR.umlauts"),
                             "\xc4\xd6\xdc\xe4\xf6\xfc\xdf")

            tarinfo = tar.getmember("pax/regtype2")
            self.assertEqual(tarinfo.uname, "")
            self.assertEqual(tarinfo.gname, "bar")
            self.assertEqual(tarinfo.pax_headers.get("VENDOR.umlauts"),
                             "\xc4\xd6\xdc\xe4\xf6\xfc\xdf")

            tarinfo = tar.getmember("pax/regtype3")
            self.assertEqual(tarinfo.uname, "tarfile")
            self.assertEqual(tarinfo.gname, "tarfile")
            self.assertEqual(tarinfo.pax_headers.get("VENDOR.umlauts"),
                             "\xc4\xd6\xdc\xe4\xf6\xfc\xdf")
        finally:
            tar.close()

    def test_pax_number_fields(self):
        # All following number fields are read from the pax header.
        tar = tarfile.open(tarname, encoding="iso8859-1")
        try:
            tarinfo = tar.getmember("pax/regtype4")
            self.assertEqual(tarinfo.size, 7011)
            self.assertEqual(tarinfo.uid, 123)
            self.assertEqual(tarinfo.gid, 123)
            self.assertEqual(tarinfo.mtime, 1041808783.0)
            self.assertEqual(type(tarinfo.mtime), float)
            self.assertEqual(float(tarinfo.pax_headers["atime"]), 1041808783.0)
            self.assertEqual(float(tarinfo.pax_headers["ctime"]), 1041808783.0)
        finally:
            tar.close()


class WriteTestBase(TarTest):
    # Put all write tests in here that are supposed to be tested
    # in all possible mode combinations.

    def test_fileobj_no_close(self):
        fobj = io.BytesIO()
        tar = tarfile.open(fileobj=fobj, mode=self.mode)
        tar.addfile(tarfile.TarInfo("foo"))
        tar.close()
        self.assertFalse(fobj.closed, "external fileobjs must never closed")
        # Issue #20238: Incomplete gzip output with mode="w:gz"
        data = fobj.getvalue()
        del tar
        support.gc_collect()
        self.assertFalse(fobj.closed)
        self.assertEqual(data, fobj.getvalue())

    def test_eof_marker(self):
        # Make sure an end of archive marker is written (two zero blocks).
        # tarfile insists on aligning archives to a 20 * 512 byte recordsize.
        # So, we create an archive that has exactly 10240 bytes without the
        # marker, and has 20480 bytes once the marker is written.
        with tarfile.open(tmpname, self.mode) as tar:
            t = tarfile.TarInfo("foo")
            t.size = tarfile.RECORDSIZE - tarfile.BLOCKSIZE
            tar.addfile(t, io.BytesIO(b"a" * t.size))

        with self.open(tmpname, "rb") as fobj:
            self.assertEqual(len(fobj.read()), tarfile.RECORDSIZE * 2)


class WriteTest(WriteTestBase, unittest.TestCase):

    prefix = "w:"

    def test_100_char_name(self):
        # The name field in a tar header stores strings of at most 100 chars.
        # If a string is shorter than 100 chars it has to be padded with '\0',
        # which implies that a string of exactly 100 chars is stored without
        # a trailing '\0'.
        name = "0123456789" * 10
        tar = tarfile.open(tmpname, self.mode)
        try:
            t = tarfile.TarInfo(name)
            tar.addfile(t)
        finally:
            tar.close()

        tar = tarfile.open(tmpname)
        try:
            self.assertEqual(tar.getnames()[0], name,
                    "failed to store 100 char filename")
        finally:
            tar.close()

    def test_tar_size(self):
        # Test for bug #1013882.
        tar = tarfile.open(tmpname, self.mode)
        try:
            path = os.path.join(TEMPDIR, "file")
            with open(path, "wb") as fobj:
                fobj.write(b"aaa")
            tar.add(path)
        finally:
            tar.close()
        self.assertGreater(os.path.getsize(tmpname), 0,
                "tarfile is empty")

    # The test_*_size tests test for bug #1167128.
    def test_file_size(self):
        tar = tarfile.open(tmpname, self.mode)
        try:
            path = os.path.join(TEMPDIR, "file")
            with open(path, "wb"):
                pass
            tarinfo = tar.gettarinfo(path)
            self.assertEqual(tarinfo.size, 0)

            with open(path, "wb") as fobj:
                fobj.write(b"aaa")
            tarinfo = tar.gettarinfo(path)
            self.assertEqual(tarinfo.size, 3)
        finally:
            tar.close()

    def test_directory_size(self):
        path = os.path.join(TEMPDIR, "directory")
        os.mkdir(path)
        try:
            tar = tarfile.open(tmpname, self.mode)
            try:
                tarinfo = tar.gettarinfo(path)
                self.assertEqual(tarinfo.size, 0)
            finally:
                tar.close()
        finally:
            support.rmdir(path)

    def test_gettarinfo_pathlike_name(self):
        with tarfile.open(tmpname, self.mode) as tar:
            path = pathlib.Path(TEMPDIR) / "file"
            with open(path, "wb") as fobj:
                fobj.write(b"aaa")
            tarinfo = tar.gettarinfo(path)
            tarinfo2 = tar.gettarinfo(os.fspath(path))
            self.assertIsInstance(tarinfo.name, str)
            self.assertEqual(tarinfo.name, tarinfo2.name)
            self.assertEqual(tarinfo.size, 3)

    @unittest.skipUnless(hasattr(os, "link"),
                         "Missing hardlink implementation")
    def test_link_size(self):
        link = os.path.join(TEMPDIR, "link")
        target = os.path.join(TEMPDIR, "link_target")
        with open(target, "wb") as fobj:
            fobj.write(b"aaa")
        os.link(target, link)
        try:
            tar = tarfile.open(tmpname, self.mode)
            try:
                # Record the link target in the inodes list.
                tar.gettarinfo(target)
                tarinfo = tar.gettarinfo(link)
                self.assertEqual(tarinfo.size, 0)
            finally:
                tar.close()
        finally:
            support.unlink(target)
            support.unlink(link)

    @support.skip_unless_symlink
    def test_symlink_size(self):
        path = os.path.join(TEMPDIR, "symlink")
        os.symlink("link_target", path)
        try:
            tar = tarfile.open(tmpname, self.mode)
            try:
                tarinfo = tar.gettarinfo(path)
                self.assertEqual(tarinfo.size, 0)
            finally:
                tar.close()
        finally:
            support.unlink(path)

    def test_add_self(self):
        # Test for #1257255.
        dstname = os.path.abspath(tmpname)
        tar = tarfile.open(tmpname, self.mode)
        try:
            self.assertEqual(tar.name, dstname,
                    "archive name must be absolute")
            tar.add(dstname)
            self.assertEqual(tar.getnames(), [],
                    "added the archive to itself")

            with support.change_cwd(TEMPDIR):
                tar.add(dstname)
            self.assertEqual(tar.getnames(), [],
                    "added the archive to itself")
        finally:
            tar.close()

    def test_exclude(self):
        tempdir = os.path.join(TEMPDIR, "exclude")
        os.mkdir(tempdir)
        try:
            for name in ("foo", "bar", "baz"):
                name = os.path.join(tempdir, name)
                support.create_empty_file(name)

            exclude = os.path.isfile

            tar = tarfile.open(tmpname, self.mode, encoding="iso8859-1")
            try:
                with support.check_warnings(("use the filter argument",
                                             DeprecationWarning)):
                    tar.add(tempdir, arcname="empty_dir", exclude=exclude)
            finally:
                tar.close()

            tar = tarfile.open(tmpname, "r")
            try:
                self.assertEqual(len(tar.getmembers()), 1)
                self.assertEqual(tar.getnames()[0], "empty_dir")
            finally:
                tar.close()
        finally:
            support.rmtree(tempdir)

    def test_filter(self):
        tempdir = os.path.join(TEMPDIR, "filter")
        os.mkdir(tempdir)
        try:
            for name in ("foo", "bar", "baz"):
                name = os.path.join(tempdir, name)
                support.create_empty_file(name)

            def filter(tarinfo):
                if os.path.basename(tarinfo.name) == "bar":
                    return
                tarinfo.uid = 123
                tarinfo.uname = "foo"
                return tarinfo

            tar = tarfile.open(tmpname, self.mode, encoding="iso8859-1")
            try:
                tar.add(tempdir, arcname="empty_dir", filter=filter)
            finally:
                tar.close()

            # Verify that filter is a keyword-only argument
            with self.assertRaises(TypeError):
                tar.add(tempdir, "empty_dir", True, None, filter)

            tar = tarfile.open(tmpname, "r")
            try:
                for tarinfo in tar:
                    self.assertEqual(tarinfo.uid, 123)
                    self.assertEqual(tarinfo.uname, "foo")
                self.assertEqual(len(tar.getmembers()), 3)
            finally:
                tar.close()
        finally:
            support.rmtree(tempdir)

    # Guarantee that stored pathnames are not modified. Don't
    # remove ./ or ../ or double slashes. Still make absolute
    # pathnames relative.
    # For details see bug #6054.
    def _test_pathname(self, path, cmp_path=None, dir=False):
        # Create a tarfile with an empty member named path
        # and compare the stored name with the original.
        foo = os.path.join(TEMPDIR, "foo")
        if not dir:
            support.create_empty_file(foo)
        else:
            os.mkdir(foo)

        tar = tarfile.open(tmpname, self.mode)
        try:
            tar.add(foo, arcname=path)
        finally:
            tar.close()

        tar = tarfile.open(tmpname, "r")
        try:
            t = tar.next()
        finally:
            tar.close()

        if not dir:
            support.unlink(foo)
        else:
            support.rmdir(foo)

        self.assertEqual(t.name, cmp_path or path.replace(os.sep, "/"))


    @support.skip_unless_symlink
    def test_extractall_symlinks(self):
        # Test if extractall works properly when tarfile contains symlinks
        tempdir = os.path.join(TEMPDIR, "testsymlinks")
        temparchive = os.path.join(TEMPDIR, "testsymlinks.tar")
        os.mkdir(tempdir)
        try:
            source_file = os.path.join(tempdir,'source')
            target_file = os.path.join(tempdir,'symlink')
            with open(source_file,'w') as f:
                f.write('something\n')
            os.symlink(source_file, target_file)
            tar = tarfile.open(temparchive,'w')
            tar.add(source_file)
            tar.add(target_file)
            tar.close()
            # Let's extract it to the location which contains the symlink
            tar = tarfile.open(temparchive,'r')
            # this should not raise OSError: [Errno 17] File exists
            try:
                tar.extractall(path=tempdir)
            except OSError:
                self.fail("extractall failed with symlinked files")
            finally:
                tar.close()
        finally:
            support.unlink(temparchive)
            support.rmtree(tempdir)

    def test_pathnames(self):
        self._test_pathname("foo")
        self._test_pathname(os.path.join("foo", ".", "bar"))
        self._test_pathname(os.path.join("foo", "..", "bar"))
        self._test_pathname(os.path.join(".", "foo"))
        self._test_pathname(os.path.join(".", "foo", "."))
        self._test_pathname(os.path.join(".", "foo", ".", "bar"))
        self._test_pathname(os.path.join(".", "foo", "..", "bar"))
        self._test_pathname(os.path.join(".", "foo", "..", "bar"))
        self._test_pathname(os.path.join("..", "foo"))
        self._test_pathname(os.path.join("..", "foo", ".."))
        self._test_pathname(os.path.join("..", "foo", ".", "bar"))
        self._test_pathname(os.path.join("..", "foo", "..", "bar"))

        self._test_pathname("foo" + os.sep + os.sep + "bar")
        self._test_pathname("foo" + os.sep + os.sep, "foo", dir=True)

    def test_abs_pathnames(self):
        if sys.platform == "win32":
            self._test_pathname("C:\\foo", "foo")
        else:
            self._test_pathname("/foo", "foo")
            self._test_pathname("///foo", "foo")

    def test_cwd(self):
        # Test adding the current working directory.
        with support.change_cwd(TEMPDIR):
            tar = tarfile.open(tmpname, self.mode)
            try:
                tar.add(".")
            finally:
                tar.close()

            tar = tarfile.open(tmpname, "r")
            try:
                for t in tar:
                    if t.name != ".":
                        self.assertTrue(t.name.startswith("./"), t.name)
            finally:
                tar.close()

    def test_open_nonwritable_fileobj(self):
        for exctype in OSError, EOFError, RuntimeError:
            class BadFile(io.BytesIO):
                first = True
                def write(self, data):
                    if self.first:
                        self.first = False
                        raise exctype

            f = BadFile()
            with self.assertRaises(exctype):
                tar = tarfile.open(tmpname, self.mode, fileobj=f,
                                   format=tarfile.PAX_FORMAT,
                                   pax_headers={'non': 'empty'})
            self.assertFalse(f.closed)

class GzipWriteTest(GzipTest, WriteTest):
    pass

class Bz2WriteTest(Bz2Test, WriteTest):
    pass

class LzmaWriteTest(LzmaTest, WriteTest):
    pass


class StreamWriteTest(WriteTestBase, unittest.TestCase):

    prefix = "w|"
    decompressor = None

    def test_stream_padding(self):
        # Test for bug #1543303.
        tar = tarfile.open(tmpname, self.mode)
        tar.close()
        if self.decompressor:
            dec = self.decompressor()
            with open(tmpname, "rb") as fobj:
                data = fobj.read()
            data = dec.decompress(data)
            self.assertFalse(dec.unused_data, "found trailing data")
        else:
            with self.open(tmpname) as fobj:
                data = fobj.read()
        self.assertEqual(data.count(b"\0"), tarfile.RECORDSIZE,
                        "incorrect zero padding")

    @unittest.skipUnless(sys.platform != "win32" and hasattr(os, "umask"),
                         "Missing umask implementation")
    def test_file_mode(self):
        # Test for issue #8464: Create files with correct
        # permissions.
        if os.path.exists(tmpname):
            support.unlink(tmpname)

        original_umask = os.umask(0o022)
        try:
            tar = tarfile.open(tmpname, self.mode)
            tar.close()
            mode = os.stat(tmpname).st_mode & 0o777
            self.assertEqual(mode, 0o644, "wrong file permissions")
        finally:
            os.umask(original_umask)

class GzipStreamWriteTest(GzipTest, StreamWriteTest):
    pass

class Bz2StreamWriteTest(Bz2Test, StreamWriteTest):
    decompressor = bz2.BZ2Decompressor if bz2 else None

class LzmaStreamWriteTest(LzmaTest, StreamWriteTest):
    decompressor = lzma.LZMADecompressor if lzma else None


class GNUWriteTest(unittest.TestCase):
    # This testcase checks for correct creation of GNU Longname
    # and Longlink extended headers (cp. bug #812325).

    def _length(self, s):
        blocks = len(s) // 512 + 1
        return blocks * 512

    def _calc_size(self, name, link=None):
        # Initial tar header
        count = 512

        if len(name) > tarfile.LENGTH_NAME:
            # GNU longname extended header + longname
            count += 512
            count += self._length(name)
        if link is not None and len(link) > tarfile.LENGTH_LINK:
            # GNU longlink extended header + longlink
            count += 512
            count += self._length(link)
        return count

    def _test(self, name, link=None):
        tarinfo = tarfile.TarInfo(name)
        if link:
            tarinfo.linkname = link
            tarinfo.type = tarfile.LNKTYPE

        tar = tarfile.open(tmpname, "w")
        try:
            tar.format = tarfile.GNU_FORMAT
            tar.addfile(tarinfo)

            v1 = self._calc_size(name, link)
            v2 = tar.offset
            self.assertEqual(v1, v2, "GNU longname/longlink creation failed")
        finally:
            tar.close()

        tar = tarfile.open(tmpname)
        try:
            member = tar.next()
            self.assertIsNotNone(member,
                    "unable to read longname member")
            self.assertEqual(tarinfo.name, member.name,
                    "unable to read longname member")
            self.assertEqual(tarinfo.linkname, member.linkname,
                    "unable to read longname member")
        finally:
            tar.close()

    def test_longname_1023(self):
        self._test(("longnam/" * 127) + "longnam")

    def test_longname_1024(self):
        self._test(("longnam/" * 127) + "longname")

    def test_longname_1025(self):
        self._test(("longnam/" * 127) + "longname_")

    def test_longlink_1023(self):
        self._test("name", ("longlnk/" * 127) + "longlnk")

    def test_longlink_1024(self):
        self._test("name", ("longlnk/" * 127) + "longlink")

    def test_longlink_1025(self):
        self._test("name", ("longlnk/" * 127) + "longlink_")

    def test_longnamelink_1023(self):
        self._test(("longnam/" * 127) + "longnam",
                   ("longlnk/" * 127) + "longlnk")

    def test_longnamelink_1024(self):
        self._test(("longnam/" * 127) + "longname",
                   ("longlnk/" * 127) + "longlink")

    def test_longnamelink_1025(self):
        self._test(("longnam/" * 127) + "longname_",
                   ("longlnk/" * 127) + "longlink_")


class CreateTest(WriteTestBase, unittest.TestCase):

    prefix = "x:"

    file_path = os.path.join(TEMPDIR, "spameggs42")

    def setUp(self):
        support.unlink(tmpname)

    @classmethod
    def setUpClass(cls):
        with open(cls.file_path, "wb") as fobj:
            fobj.write(b"aaa")

    @classmethod
    def tearDownClass(cls):
        support.unlink(cls.file_path)

    def test_create(self):
        with tarfile.open(tmpname, self.mode) as tobj:
            tobj.add(self.file_path)

        with self.taropen(tmpname) as tobj:
            names = tobj.getnames()
        self.assertEqual(len(names), 1)
        self.assertIn('spameggs42', names[0])

    def test_create_existing(self):
        with tarfile.open(tmpname, self.mode) as tobj:
            tobj.add(self.file_path)

        with self.assertRaises(FileExistsError):
            tobj = tarfile.open(tmpname, self.mode)

        with self.taropen(tmpname) as tobj:
            names = tobj.getnames()
        self.assertEqual(len(names), 1)
        self.assertIn('spameggs42', names[0])

    def test_create_taropen(self):
        with self.taropen(tmpname, "x") as tobj:
            tobj.add(self.file_path)

        with self.taropen(tmpname) as tobj:
            names = tobj.getnames()
        self.assertEqual(len(names), 1)
        self.assertIn('spameggs42', names[0])

    def test_create_existing_taropen(self):
        with self.taropen(tmpname, "x") as tobj:
            tobj.add(self.file_path)

        with self.assertRaises(FileExistsError):
            with self.taropen(tmpname, "x"):
                pass

        with self.taropen(tmpname) as tobj:
            names = tobj.getnames()
        self.assertEqual(len(names), 1)
        self.assertIn("spameggs42", names[0])

    def test_create_pathlike_name(self):
        with tarfile.open(pathlib.Path(tmpname), self.mode) as tobj:
            self.assertIsInstance(tobj.name, str)
            self.assertEqual(tobj.name, os.path.abspath(tmpname))
            tobj.add(pathlib.Path(self.file_path))
            names = tobj.getnames()
        self.assertEqual(len(names), 1)
        self.assertIn('spameggs42', names[0])

        with self.taropen(tmpname) as tobj:
            names = tobj.getnames()
        self.assertEqual(len(names), 1)
        self.assertIn('spameggs42', names[0])

    def test_create_taropen_pathlike_name(self):
        with self.taropen(pathlib.Path(tmpname), "x") as tobj:
            self.assertIsInstance(tobj.name, str)
            self.assertEqual(tobj.name, os.path.abspath(tmpname))
            tobj.add(pathlib.Path(self.file_path))
            names = tobj.getnames()
        self.assertEqual(len(names), 1)
        self.assertIn('spameggs42', names[0])

        with self.taropen(tmpname) as tobj:
            names = tobj.getnames()
        self.assertEqual(len(names), 1)
        self.assertIn('spameggs42', names[0])


class GzipCreateTest(GzipTest, CreateTest):
    pass


class Bz2CreateTest(Bz2Test, CreateTest):
    pass


class LzmaCreateTest(LzmaTest, CreateTest):
    pass


class CreateWithXModeTest(CreateTest):

    prefix = "x"

    test_create_taropen = None
    test_create_existing_taropen = None


@unittest.skipUnless(hasattr(os, "link"), "Missing hardlink implementation")
class HardlinkTest(unittest.TestCase):
    # Test the creation of LNKTYPE (hardlink) members in an archive.

    def setUp(self):
        self.foo = os.path.join(TEMPDIR, "foo")
        self.bar = os.path.join(TEMPDIR, "bar")

        with open(self.foo, "wb") as fobj:
            fobj.write(b"foo")

        os.link(self.foo, self.bar)

        self.tar = tarfile.open(tmpname, "w")
        self.tar.add(self.foo)

    def tearDown(self):
        self.tar.close()
        support.unlink(self.foo)
        support.unlink(self.bar)

    def test_add_twice(self):
        # The same name will be added as a REGTYPE every
        # time regardless of st_nlink.
        tarinfo = self.tar.gettarinfo(self.foo)
        self.assertEqual(tarinfo.type, tarfile.REGTYPE,
                "add file as regular failed")

    def test_add_hardlink(self):
        tarinfo = self.tar.gettarinfo(self.bar)
        self.assertEqual(tarinfo.type, tarfile.LNKTYPE,
                "add file as hardlink failed")

    def test_dereference_hardlink(self):
        self.tar.dereference = True
        tarinfo = self.tar.gettarinfo(self.bar)
        self.assertEqual(tarinfo.type, tarfile.REGTYPE,
                "dereferencing hardlink failed")


class PaxWriteTest(GNUWriteTest):

    def _test(self, name, link=None):
        # See GNUWriteTest.
        tarinfo = tarfile.TarInfo(name)
        if link:
            tarinfo.linkname = link
            tarinfo.type = tarfile.LNKTYPE

        tar = tarfile.open(tmpname, "w", format=tarfile.PAX_FORMAT)
        try:
            tar.addfile(tarinfo)
        finally:
            tar.close()

        tar = tarfile.open(tmpname)
        try:
            if link:
                l = tar.getmembers()[0].linkname
                self.assertEqual(link, l, "PAX longlink creation failed")
            else:
                n = tar.getmembers()[0].name
                self.assertEqual(name, n, "PAX longname creation failed")
        finally:
            tar.close()

    def test_pax_global_header(self):
        pax_headers = {
                "foo": "bar",
                "uid": "0",
                "mtime": "1.23",
                "test": "\xe4\xf6\xfc",
                "\xe4\xf6\xfc": "test"}

        tar = tarfile.open(tmpname, "w", format=tarfile.PAX_FORMAT,
                pax_headers=pax_headers)
        try:
            tar.addfile(tarfile.TarInfo("test"))
        finally:
            tar.close()

        # Test if the global header was written correctly.
        tar = tarfile.open(tmpname, encoding="iso8859-1")
        try:
            self.assertEqual(tar.pax_headers, pax_headers)
            self.assertEqual(tar.getmembers()[0].pax_headers, pax_headers)
            # Test if all the fields are strings.
            for key, val in tar.pax_headers.items():
                self.assertIsNot(type(key), bytes)
                self.assertIsNot(type(val), bytes)
                if key in tarfile.PAX_NUMBER_FIELDS:
                    try:
                        tarfile.PAX_NUMBER_FIELDS[key](val)
                    except (TypeError, ValueError):
                        self.fail("unable to convert pax header field")
        finally:
            tar.close()

    def test_pax_extended_header(self):
        # The fields from the pax header have priority over the
        # TarInfo.
        pax_headers = {"path": "foo", "uid": "123"}

        tar = tarfile.open(tmpname, "w", format=tarfile.PAX_FORMAT,
                           encoding="iso8859-1")
        try:
            t = tarfile.TarInfo()
            t.name = "\xe4\xf6\xfc" # non-ASCII
            t.uid = 8**8 # too large
            t.pax_headers = pax_headers
            tar.addfile(t)
        finally:
            tar.close()

        tar = tarfile.open(tmpname, encoding="iso8859-1")
        try:
            t = tar.getmembers()[0]
            self.assertEqual(t.pax_headers, pax_headers)
            self.assertEqual(t.name, "foo")
            self.assertEqual(t.uid, 123)
        finally:
            tar.close()


class UnicodeTest:

    def test_iso8859_1_filename(self):
        self._test_unicode_filename("iso8859-1")

    def test_utf7_filename(self):
        self._test_unicode_filename("utf7")

    def test_utf8_filename(self):
        self._test_unicode_filename("utf-8")

    def _test_unicode_filename(self, encoding):
        tar = tarfile.open(tmpname, "w", format=self.format,
                           encoding=encoding, errors="strict")
        try:
            name = "\xe4\xf6\xfc"
            tar.addfile(tarfile.TarInfo(name))
        finally:
            tar.close()

        tar = tarfile.open(tmpname, encoding=encoding)
        try:
            self.assertEqual(tar.getmembers()[0].name, name)
        finally:
            tar.close()

    def test_unicode_filename_error(self):
        tar = tarfile.open(tmpname, "w", format=self.format,
                           encoding="ascii", errors="strict")
        try:
            tarinfo = tarfile.TarInfo()

            tarinfo.name = "\xe4\xf6\xfc"
            self.assertRaises(UnicodeError, tar.addfile, tarinfo)

            tarinfo.name = "foo"
            tarinfo.uname = "\xe4\xf6\xfc"
            self.assertRaises(UnicodeError, tar.addfile, tarinfo)
        finally:
            tar.close()

    def test_unicode_argument(self):
        tar = tarfile.open(tarname, "r",
                           encoding="iso8859-1", errors="strict")
        try:
            for t in tar:
                self.assertIs(type(t.name), str)
                self.assertIs(type(t.linkname), str)
                self.assertIs(type(t.uname), str)
                self.assertIs(type(t.gname), str)
        finally:
            tar.close()

    def test_uname_unicode(self):
        t = tarfile.TarInfo("foo")
        t.uname = "\xe4\xf6\xfc"
        t.gname = "\xe4\xf6\xfc"

        tar = tarfile.open(tmpname, mode="w", format=self.format,
                           encoding="iso8859-1")
        try:
            tar.addfile(t)
        finally:
            tar.close()

        tar = tarfile.open(tmpname, encoding="iso8859-1")
        try:
            t = tar.getmember("foo")
            self.assertEqual(t.uname, "\xe4\xf6\xfc")
            self.assertEqual(t.gname, "\xe4\xf6\xfc")

            if self.format != tarfile.PAX_FORMAT:
                tar.close()
                tar = tarfile.open(tmpname, encoding="ascii")
                t = tar.getmember("foo")
                self.assertEqual(t.uname, "\udce4\udcf6\udcfc")
                self.assertEqual(t.gname, "\udce4\udcf6\udcfc")
        finally:
            tar.close()


class UstarUnicodeTest(UnicodeTest, unittest.TestCase):

    format = tarfile.USTAR_FORMAT

    # Test whether the utf-8 encoded version of a filename exceeds the 100
    # bytes name field limit (every occurrence of '\xff' will be expanded to 2
    # bytes).
    def test_unicode_name1(self):
        self._test_ustar_name("0123456789" * 10)
        self._test_ustar_name("0123456789" * 10 + "0", ValueError)
        self._test_ustar_name("0123456789" * 9 + "01234567\xff")
        self._test_ustar_name("0123456789" * 9 + "012345678\xff", ValueError)

    def test_unicode_name2(self):
        self._test_ustar_name("0123456789" * 9 + "012345\xff\xff")
        self._test_ustar_name("0123456789" * 9 + "0123456\xff\xff", ValueError)

    # Test whether the utf-8 encoded version of a filename exceeds the 155
    # bytes prefix + '/' + 100 bytes name limit.
    def test_unicode_longname1(self):
        self._test_ustar_name("0123456789" * 15 + "01234/" + "0123456789" * 10)
        self._test_ustar_name("0123456789" * 15 + "0123/4" + "0123456789" * 10, ValueError)
        self._test_ustar_name("0123456789" * 15 + "012\xff/" + "0123456789" * 10)
        self._test_ustar_name("0123456789" * 15 + "0123\xff/" + "0123456789" * 10, ValueError)

    def test_unicode_longname2(self):
        self._test_ustar_name("0123456789" * 15 + "01\xff/2" + "0123456789" * 10, ValueError)
        self._test_ustar_name("0123456789" * 15 + "01\xff\xff/" + "0123456789" * 10, ValueError)

    def test_unicode_longname3(self):
        self._test_ustar_name("0123456789" * 15 + "01\xff\xff/2" + "0123456789" * 10, ValueError)
        self._test_ustar_name("0123456789" * 15 + "01234/" + "0123456789" * 9 + "01234567\xff")
        self._test_ustar_name("0123456789" * 15 + "01234/" + "0123456789" * 9 + "012345678\xff", ValueError)

    def test_unicode_longname4(self):
        self._test_ustar_name("0123456789" * 15 + "01234/" + "0123456789" * 9 + "012345\xff\xff")
        self._test_ustar_name("0123456789" * 15 + "01234/" + "0123456789" * 9 + "0123456\xff\xff", ValueError)

    def _test_ustar_name(self, name, exc=None):
        with tarfile.open(tmpname, "w", format=self.format, encoding="utf-8") as tar:
            t = tarfile.TarInfo(name)
            if exc is None:
                tar.addfile(t)
            else:
                self.assertRaises(exc, tar.addfile, t)

        if exc is None:
            with tarfile.open(tmpname, "r", encoding="utf-8") as tar:
                for t in tar:
                    self.assertEqual(name, t.name)
                    break

    # Test the same as above for the 100 bytes link field.
    def test_unicode_link1(self):
        self._test_ustar_link("0123456789" * 10)
        self._test_ustar_link("0123456789" * 10 + "0", ValueError)
        self._test_ustar_link("0123456789" * 9 + "01234567\xff")
        self._test_ustar_link("0123456789" * 9 + "012345678\xff", ValueError)

    def test_unicode_link2(self):
        self._test_ustar_link("0123456789" * 9 + "012345\xff\xff")
        self._test_ustar_link("0123456789" * 9 + "0123456\xff\xff", ValueError)

    def _test_ustar_link(self, name, exc=None):
        with tarfile.open(tmpname, "w", format=self.format, encoding="utf-8") as tar:
            t = tarfile.TarInfo("foo")
            t.linkname = name
            if exc is None:
                tar.addfile(t)
            else:
                self.assertRaises(exc, tar.addfile, t)

        if exc is None:
            with tarfile.open(tmpname, "r", encoding="utf-8") as tar:
                for t in tar:
                    self.assertEqual(name, t.linkname)
                    break


class GNUUnicodeTest(UnicodeTest, unittest.TestCase):

    format = tarfile.GNU_FORMAT

    def test_bad_pax_header(self):
        # Test for issue #8633. GNU tar <= 1.23 creates raw binary fields
        # without a hdrcharset=BINARY header.
        for encoding, name in (
                ("utf-8", "pax/bad-pax-\udce4\udcf6\udcfc"),
                ("iso8859-1", "pax/bad-pax-\xe4\xf6\xfc"),):
            with tarfile.open(tarname, encoding=encoding,
                              errors="surrogateescape") as tar:
                try:
                    t = tar.getmember(name)
                except KeyError:
                    self.fail("unable to read bad GNU tar pax header")


class PAXUnicodeTest(UnicodeTest, unittest.TestCase):

    format = tarfile.PAX_FORMAT

    # PAX_FORMAT ignores encoding in write mode.
    test_unicode_filename_error = None

    def test_binary_header(self):
        # Test a POSIX.1-2008 compatible header with a hdrcharset=BINARY field.
        for encoding, name in (
                ("utf-8", "pax/hdrcharset-\udce4\udcf6\udcfc"),
                ("iso8859-1", "pax/hdrcharset-\xe4\xf6\xfc"),):
            with tarfile.open(tarname, encoding=encoding,
                              errors="surrogateescape") as tar:
                try:
                    t = tar.getmember(name)
                except KeyError:
                    self.fail("unable to read POSIX.1-2008 binary header")


class AppendTestBase:
    # Test append mode (cp. patch #1652681).

    def setUp(self):
        self.tarname = tmpname
        if os.path.exists(self.tarname):
            support.unlink(self.tarname)

    def _create_testtar(self, mode="w:"):
        with tarfile.open(tarname, encoding="iso8859-1") as src:
            t = src.getmember("ustar/regtype")
            t.name = "foo"
            with src.extractfile(t) as f:
                with tarfile.open(self.tarname, mode) as tar:
                    tar.addfile(t, f)

    def test_append_compressed(self):
        self._create_testtar("w:" + self.suffix)
        self.assertRaises(tarfile.ReadError, tarfile.open, tmpname, "a")

class AppendTest(AppendTestBase, unittest.TestCase):
    test_append_compressed = None

    def _add_testfile(self, fileobj=None):
        with tarfile.open(self.tarname, "a", fileobj=fileobj) as tar:
            tar.addfile(tarfile.TarInfo("bar"))

    def _test(self, names=["bar"], fileobj=None):
        with tarfile.open(self.tarname, fileobj=fileobj) as tar:
            self.assertEqual(tar.getnames(), names)

    def test_non_existing(self):
        self._add_testfile()
        self._test()

    def test_empty(self):
        tarfile.open(self.tarname, "w:").close()
        self._add_testfile()
        self._test()

    def test_empty_fileobj(self):
        fobj = io.BytesIO(b"\0" * 1024)
        self._add_testfile(fobj)
        fobj.seek(0)
        self._test(fileobj=fobj)

    def test_fileobj(self):
        self._create_testtar()
        with open(self.tarname, "rb") as fobj:
            data = fobj.read()
        fobj = io.BytesIO(data)
        self._add_testfile(fobj)
        fobj.seek(0)
        self._test(names=["foo", "bar"], fileobj=fobj)

    def test_existing(self):
        self._create_testtar()
        self._add_testfile()
        self._test(names=["foo", "bar"])

    # Append mode is supposed to fail if the tarfile to append to
    # does not end with a zero block.
    def _test_error(self, data):
        with open(self.tarname, "wb") as fobj:
            fobj.write(data)
        self.assertRaises(tarfile.ReadError, self._add_testfile)

    def test_null(self):
        self._test_error(b"")

    def test_incomplete(self):
        self._test_error(b"\0" * 13)

    def test_premature_eof(self):
        data = tarfile.TarInfo("foo").tobuf()
        self._test_error(data)

    def test_trailing_garbage(self):
        data = tarfile.TarInfo("foo").tobuf()
        self._test_error(data + b"\0" * 13)

    def test_invalid(self):
        self._test_error(b"a" * 512)

class GzipAppendTest(GzipTest, AppendTestBase, unittest.TestCase):
    pass

class Bz2AppendTest(Bz2Test, AppendTestBase, unittest.TestCase):
    pass

class LzmaAppendTest(LzmaTest, AppendTestBase, unittest.TestCase):
    pass


class LimitsTest(unittest.TestCase):

    def test_ustar_limits(self):
        # 100 char name
        tarinfo = tarfile.TarInfo("0123456789" * 10)
        tarinfo.tobuf(tarfile.USTAR_FORMAT)

        # 101 char name that cannot be stored
        tarinfo = tarfile.TarInfo("0123456789" * 10 + "0")
        self.assertRaises(ValueError, tarinfo.tobuf, tarfile.USTAR_FORMAT)

        # 256 char name with a slash at pos 156
        tarinfo = tarfile.TarInfo("123/" * 62 + "longname")
        tarinfo.tobuf(tarfile.USTAR_FORMAT)

        # 256 char name that cannot be stored
        tarinfo = tarfile.TarInfo("1234567/" * 31 + "longname")
        self.assertRaises(ValueError, tarinfo.tobuf, tarfile.USTAR_FORMAT)

        # 512 char name
        tarinfo = tarfile.TarInfo("123/" * 126 + "longname")
        self.assertRaises(ValueError, tarinfo.tobuf, tarfile.USTAR_FORMAT)

        # 512 char linkname
        tarinfo = tarfile.TarInfo("longlink")
        tarinfo.linkname = "123/" * 126 + "longname"
        self.assertRaises(ValueError, tarinfo.tobuf, tarfile.USTAR_FORMAT)

        # uid > 8 digits
        tarinfo = tarfile.TarInfo("name")
        tarinfo.uid = 0o10000000
        self.assertRaises(ValueError, tarinfo.tobuf, tarfile.USTAR_FORMAT)

    def test_gnu_limits(self):
        tarinfo = tarfile.TarInfo("123/" * 126 + "longname")
        tarinfo.tobuf(tarfile.GNU_FORMAT)

        tarinfo = tarfile.TarInfo("longlink")
        tarinfo.linkname = "123/" * 126 + "longname"
        tarinfo.tobuf(tarfile.GNU_FORMAT)

        # uid >= 256 ** 7
        tarinfo = tarfile.TarInfo("name")
        tarinfo.uid = 0o4000000000000000000
        self.assertRaises(ValueError, tarinfo.tobuf, tarfile.GNU_FORMAT)

    def test_pax_limits(self):
        tarinfo = tarfile.TarInfo("123/" * 126 + "longname")
        tarinfo.tobuf(tarfile.PAX_FORMAT)

        tarinfo = tarfile.TarInfo("longlink")
        tarinfo.linkname = "123/" * 126 + "longname"
        tarinfo.tobuf(tarfile.PAX_FORMAT)

        tarinfo = tarfile.TarInfo("name")
        tarinfo.uid = 0o4000000000000000000
        tarinfo.tobuf(tarfile.PAX_FORMAT)


class MiscTest(unittest.TestCase):

    def test_char_fields(self):
        self.assertEqual(tarfile.stn("foo", 8, "ascii", "strict"),
                         b"foo\0\0\0\0\0")
        self.assertEqual(tarfile.stn("foobar", 3, "ascii", "strict"),
                         b"foo")
        self.assertEqual(tarfile.nts(b"foo\0\0\0\0\0", "ascii", "strict"),
                         "foo")
        self.assertEqual(tarfile.nts(b"foo\0bar\0", "ascii", "strict"),
                         "foo")

    def test_read_number_fields(self):
        # Issue 13158: Test if GNU tar specific base-256 number fields
        # are decoded correctly.
        self.assertEqual(tarfile.nti(b"0000001\x00"), 1)
        self.assertEqual(tarfile.nti(b"7777777\x00"), 0o7777777)
        self.assertEqual(tarfile.nti(b"\x80\x00\x00\x00\x00\x20\x00\x00"),
                         0o10000000)
        self.assertEqual(tarfile.nti(b"\x80\x00\x00\x00\xff\xff\xff\xff"),
                         0xffffffff)
        self.assertEqual(tarfile.nti(b"\xff\xff\xff\xff\xff\xff\xff\xff"),
                         -1)
        self.assertEqual(tarfile.nti(b"\xff\xff\xff\xff\xff\xff\xff\x9c"),
                         -100)
        self.assertEqual(tarfile.nti(b"\xff\x00\x00\x00\x00\x00\x00\x00"),
                         -0x100000000000000)

        # Issue 24514: Test if empty number fields are converted to zero.
        self.assertEqual(tarfile.nti(b"\0"), 0)
        self.assertEqual(tarfile.nti(b"       \0"), 0)

    def test_write_number_fields(self):
        self.assertEqual(tarfile.itn(1), b"0000001\x00")
        self.assertEqual(tarfile.itn(0o7777777), b"7777777\x00")
        self.assertEqual(tarfile.itn(0o10000000),
                         b"\x80\x00\x00\x00\x00\x20\x00\x00")
        self.assertEqual(tarfile.itn(0xffffffff),
                         b"\x80\x00\x00\x00\xff\xff\xff\xff")
        self.assertEqual(tarfile.itn(-1),
                         b"\xff\xff\xff\xff\xff\xff\xff\xff")
        self.assertEqual(tarfile.itn(-100),
                         b"\xff\xff\xff\xff\xff\xff\xff\x9c")
        self.assertEqual(tarfile.itn(-0x100000000000000),
                         b"\xff\x00\x00\x00\x00\x00\x00\x00")

    def test_number_field_limits(self):
        with self.assertRaises(ValueError):
            tarfile.itn(-1, 8, tarfile.USTAR_FORMAT)
        with self.assertRaises(ValueError):
            tarfile.itn(0o10000000, 8, tarfile.USTAR_FORMAT)
        with self.assertRaises(ValueError):
            tarfile.itn(-0x10000000001, 6, tarfile.GNU_FORMAT)
        with self.assertRaises(ValueError):
            tarfile.itn(0x10000000000, 6, tarfile.GNU_FORMAT)

    def test__all__(self):
        blacklist = {'version', 'grp', 'pwd', 'symlink_exception',
                     'NUL', 'BLOCKSIZE', 'RECORDSIZE', 'GNU_MAGIC',
                     'POSIX_MAGIC', 'LENGTH_NAME', 'LENGTH_LINK',
                     'LENGTH_PREFIX', 'REGTYPE', 'AREGTYPE', 'LNKTYPE',
                     'SYMTYPE', 'CHRTYPE', 'BLKTYPE', 'DIRTYPE', 'FIFOTYPE',
                     'CONTTYPE', 'GNUTYPE_LONGNAME', 'GNUTYPE_LONGLINK',
                     'GNUTYPE_SPARSE', 'XHDTYPE', 'XGLTYPE', 'SOLARIS_XHDTYPE',
                     'SUPPORTED_TYPES', 'REGULAR_TYPES', 'GNU_TYPES',
                     'PAX_FIELDS', 'PAX_NAME_FIELDS', 'PAX_NUMBER_FIELDS',
                     'stn', 'nts', 'nti', 'itn', 'calc_chksums', 'copyfileobj',
                     'filemode',
                     'EmptyHeaderError', 'TruncatedHeaderError',
                     'EOFHeaderError', 'InvalidHeaderError',
                     'SubsequentHeaderError', 'ExFileObject',
                     'main'}
        support.check__all__(self, tarfile, blacklist=blacklist)


class CommandLineTest(unittest.TestCase):

    def tarfilecmd(self, *args, **kwargs):
        rc, out, err = script_helper.assert_python_ok('-m', 'tarfile', *args,
                                                      **kwargs)
        return out.replace(os.linesep.encode(), b'\n')

    def tarfilecmd_failure(self, *args):
        return script_helper.assert_python_failure('-m', 'tarfile', *args)

    def make_simple_tarfile(self, tar_name):
        files = [support.findfile('tokenize_tests.txt'),
                 support.findfile('tokenize_tests-no-coding-cookie-'
                                  'and-utf8-bom-sig-only.txt')]
        self.addCleanup(support.unlink, tar_name)
        with tarfile.open(tar_name, 'w') as tf:
            for tardata in files:
                tf.add(tardata, arcname=os.path.basename(tardata))

    def test_test_command(self):
        for tar_name in testtarnames:
            for opt in '-t', '--test':
                out = self.tarfilecmd(opt, tar_name)
                self.assertEqual(out, b'')

    def test_test_command_verbose(self):
        for tar_name in testtarnames:
            for opt in '-v', '--verbose':
                out = self.tarfilecmd(opt, '-t', tar_name)
                self.assertIn(b'is a tar archive.\n', out)

    def test_test_command_invalid_file(self):
        zipname = support.findfile('zipdir.zip')
        rc, out, err = self.tarfilecmd_failure('-t', zipname)
        self.assertIn(b' is not a tar archive.', err)
        self.assertEqual(out, b'')
        self.assertEqual(rc, 1)

        for tar_name in testtarnames:
            with self.subTest(tar_name=tar_name):
                with open(tar_name, 'rb') as f:
                    data = f.read()
                try:
                    with open(tmpname, 'wb') as f:
                        f.write(data[:511])
                    rc, out, err = self.tarfilecmd_failure('-t', tmpname)
                    self.assertEqual(out, b'')
                    self.assertEqual(rc, 1)
                finally:
                    support.unlink(tmpname)

    def test_list_command(self):
        for tar_name in testtarnames:
            with support.captured_stdout() as t:
                with tarfile.open(tar_name, 'r') as tf:
                    tf.list(verbose=False)
            expected = t.getvalue().encode('ascii', 'backslashreplace')
            for opt in '-l', '--list':
                out = self.tarfilecmd(opt, tar_name,
                                      PYTHONIOENCODING='ascii')
                self.assertEqual(out, expected)

    def test_list_command_verbose(self):
        for tar_name in testtarnames:
            with support.captured_stdout() as t:
                with tarfile.open(tar_name, 'r') as tf:
                    tf.list(verbose=True)
            expected = t.getvalue().encode('ascii', 'backslashreplace')
            for opt in '-v', '--verbose':
                out = self.tarfilecmd(opt, '-l', tar_name,
                                      PYTHONIOENCODING='ascii')
                self.assertEqual(out, expected)

    def test_list_command_invalid_file(self):
        zipname = support.findfile('zipdir.zip')
        rc, out, err = self.tarfilecmd_failure('-l', zipname)
        self.assertIn(b' is not a tar archive.', err)
        self.assertEqual(out, b'')
        self.assertEqual(rc, 1)

    def test_create_command(self):
        files = [support.findfile('tokenize_tests.txt'),
                 support.findfile('tokenize_tests-no-coding-cookie-'
                                  'and-utf8-bom-sig-only.txt')]
        for opt in '-c', '--create':
            try:
                out = self.tarfilecmd(opt, tmpname, *files)
                self.assertEqual(out, b'')
                with tarfile.open(tmpname) as tar:
                    tar.getmembers()
            finally:
                support.unlink(tmpname)

    def test_create_command_verbose(self):
        files = [support.findfile('tokenize_tests.txt'),
                 support.findfile('tokenize_tests-no-coding-cookie-'
                                  'and-utf8-bom-sig-only.txt')]
        for opt in '-v', '--verbose':
            try:
                out = self.tarfilecmd(opt, '-c', tmpname, *files)
                self.assertIn(b' file created.', out)
                with tarfile.open(tmpname) as tar:
                    tar.getmembers()
            finally:
                support.unlink(tmpname)

    def test_create_command_dotless_filename(self):
        files = [support.findfile('tokenize_tests.txt')]
        try:
            out = self.tarfilecmd('-c', dotlessname, *files)
            self.assertEqual(out, b'')
            with tarfile.open(dotlessname) as tar:
                tar.getmembers()
        finally:
            support.unlink(dotlessname)

    def test_create_command_dot_started_filename(self):
        tar_name = os.path.join(TEMPDIR, ".testtar")
        files = [support.findfile('tokenize_tests.txt')]
        try:
            out = self.tarfilecmd('-c', tar_name, *files)
            self.assertEqual(out, b'')
            with tarfile.open(tar_name) as tar:
                tar.getmembers()
        finally:
            support.unlink(tar_name)

    def test_create_command_compressed(self):
        files = [support.findfile('tokenize_tests.txt'),
                 support.findfile('tokenize_tests-no-coding-cookie-'
                                  'and-utf8-bom-sig-only.txt')]
        for filetype in (GzipTest, Bz2Test, LzmaTest):
            if not filetype.open:
                continue
            try:
                tar_name = tmpname + '.' + filetype.suffix
                out = self.tarfilecmd('-c', tar_name, *files)
                with filetype.taropen(tar_name) as tar:
                    tar.getmembers()
            finally:
                support.unlink(tar_name)

    def test_extract_command(self):
        self.make_simple_tarfile(tmpname)
        for opt in '-e', '--extract':
            try:
                with support.temp_cwd(tarextdir):
                    out = self.tarfilecmd(opt, tmpname)
                self.assertEqual(out, b'')
            finally:
                support.rmtree(tarextdir)

    def test_extract_command_verbose(self):
        self.make_simple_tarfile(tmpname)
        for opt in '-v', '--verbose':
            try:
                with support.temp_cwd(tarextdir):
                    out = self.tarfilecmd(opt, '-e', tmpname)
                self.assertIn(b' file is extracted.', out)
            finally:
                support.rmtree(tarextdir)

    def test_extract_command_different_directory(self):
        self.make_simple_tarfile(tmpname)
        try:
            with support.temp_cwd(tarextdir):
                out = self.tarfilecmd('-e', tmpname, 'spamdir')
            self.assertEqual(out, b'')
        finally:
            support.rmtree(tarextdir)

    def test_extract_command_invalid_file(self):
        zipname = support.findfile('zipdir.zip')
        with support.temp_cwd(tarextdir):
            rc, out, err = self.tarfilecmd_failure('-e', zipname)
        self.assertIn(b' is not a tar archive.', err)
        self.assertEqual(out, b'')
        self.assertEqual(rc, 1)


class ContextManagerTest(unittest.TestCase):

    def test_basic(self):
        with tarfile.open(tarname) as tar:
            self.assertFalse(tar.closed, "closed inside runtime context")
        self.assertTrue(tar.closed, "context manager failed")

    def test_closed(self):
        # The __enter__() method is supposed to raise OSError
        # if the TarFile object is already closed.
        tar = tarfile.open(tarname)
        tar.close()
        with self.assertRaises(OSError):
            with tar:
                pass

    def test_exception(self):
        # Test if the OSError exception is passed through properly.
        with self.assertRaises(Exception) as exc:
            with tarfile.open(tarname) as tar:
                raise OSError
        self.assertIsInstance(exc.exception, OSError,
                              "wrong exception raised in context manager")
        self.assertTrue(tar.closed, "context manager failed")

    def test_no_eof(self):
        # __exit__() must not write end-of-archive blocks if an
        # exception was raised.
        try:
            with tarfile.open(tmpname, "w") as tar:
                raise Exception
        except:
            pass
        self.assertEqual(os.path.getsize(tmpname), 0,
                "context manager wrote an end-of-archive block")
        self.assertTrue(tar.closed, "context manager failed")

    def test_eof(self):
        # __exit__() must write end-of-archive blocks, i.e. call
        # TarFile.close() if there was no error.
        with tarfile.open(tmpname, "w"):
            pass
        self.assertNotEqual(os.path.getsize(tmpname), 0,
                "context manager wrote no end-of-archive block")

    def test_fileobj(self):
        # Test that __exit__() did not close the external file
        # object.
        with open(tmpname, "wb") as fobj:
            try:
                with tarfile.open(fileobj=fobj, mode="w") as tar:
                    raise Exception
            except:
                pass
            self.assertFalse(fobj.closed, "external file object was closed")
            self.assertTrue(tar.closed, "context manager failed")


@unittest.skipIf(hasattr(os, "link"), "requires os.link to be missing")
class LinkEmulationTest(ReadTest, unittest.TestCase):

    # Test for issue #8741 regression. On platforms that do not support
    # symbolic or hard links tarfile tries to extract these types of members
    # as the regular files they point to.
    def _test_link_extraction(self, name):
        self.tar.extract(name, TEMPDIR)
        with open(os.path.join(TEMPDIR, name), "rb") as f:
            data = f.read()
        self.assertEqual(md5sum(data), md5_regtype)

    # See issues #1578269, #8879, and #17689 for some history on these skips
    @unittest.skipIf(hasattr(os.path, "islink"),
                     "Skip emulation - has os.path.islink but not os.link")
    def test_hardlink_extraction1(self):
        self._test_link_extraction("ustar/lnktype")

    @unittest.skipIf(hasattr(os.path, "islink"),
                     "Skip emulation - has os.path.islink but not os.link")
    def test_hardlink_extraction2(self):
        self._test_link_extraction("./ustar/linktest2/lnktype")

    @unittest.skipIf(hasattr(os, "symlink"),
                     "Skip emulation if symlink exists")
    def test_symlink_extraction1(self):
        self._test_link_extraction("ustar/symtype")

    @unittest.skipIf(hasattr(os, "symlink"),
                     "Skip emulation if symlink exists")
    def test_symlink_extraction2(self):
        self._test_link_extraction("./ustar/linktest2/symtype")


class Bz2PartialReadTest(Bz2Test, unittest.TestCase):
    # Issue5068: The _BZ2Proxy.read() method loops forever
    # on an empty or partial bzipped file.

    def _test_partial_input(self, mode):
        class MyBytesIO(io.BytesIO):
            hit_eof = False
            def read(self, n):
                if self.hit_eof:
                    raise AssertionError("infinite loop detected in "
                                         "tarfile.open()")
                self.hit_eof = self.tell() == len(self.getvalue())
                return super(MyBytesIO, self).read(n)
            def seek(self, *args):
                self.hit_eof = False
                return super(MyBytesIO, self).seek(*args)

        data = bz2.compress(tarfile.TarInfo("foo").tobuf())
        for x in range(len(data) + 1):
            try:
                tarfile.open(fileobj=MyBytesIO(data[:x]), mode=mode)
            except tarfile.ReadError:
                pass # we have no interest in ReadErrors

    def test_partial_input(self):
        self._test_partial_input("r")

    def test_partial_input_bz2(self):
        self._test_partial_input("r:bz2")


def root_is_uid_gid_0():
    try:
        import pwd, grp
    except ImportError:
        return False
    if pwd.getpwuid(0)[0] != 'root':
        return False
    if grp.getgrgid(0)[0] != 'root':
        return False
    return True


@unittest.skipUnless(hasattr(os, 'chown'), "missing os.chown")
@unittest.skipUnless(hasattr(os, 'geteuid'), "missing os.geteuid")
class NumericOwnerTest(unittest.TestCase):
    # mock the following:
    #  os.chown: so we can test what's being called
    #  os.chmod: so the modes are not actually changed. if they are, we can't
    #             delete the files/directories
    #  os.geteuid: so we can lie and say we're root (uid = 0)

    @staticmethod
    def _make_test_archive(filename_1, dirname_1, filename_2):
        # the file contents to write
        fobj = io.BytesIO(b"content")

        # create a tar file with a file, a directory, and a file within that
        #  directory. Assign various .uid/.gid values to them
        items = [(filename_1, 99, 98, tarfile.REGTYPE, fobj),
                 (dirname_1,  77, 76, tarfile.DIRTYPE, None),
                 (filename_2, 88, 87, tarfile.REGTYPE, fobj),
                 ]
        with tarfile.open(tmpname, 'w') as tarfl:
            for name, uid, gid, typ, contents in items:
                t = tarfile.TarInfo(name)
                t.uid = uid
                t.gid = gid
                t.uname = 'root'
                t.gname = 'root'
                t.type = typ
                tarfl.addfile(t, contents)

        # return the full pathname to the tar file
        return tmpname

    @staticmethod
    @contextmanager
    def _setup_test(mock_geteuid):
        mock_geteuid.return_value = 0  # lie and say we're root
        fname = 'numeric-owner-testfile'
        dirname = 'dir'

        # the names we want stored in the tarfile
        filename_1 = fname
        dirname_1 = dirname
        filename_2 = os.path.join(dirname, fname)

        # create the tarfile with the contents we're after
        tar_filename = NumericOwnerTest._make_test_archive(filename_1,
                                                           dirname_1,
                                                           filename_2)

        # open the tarfile for reading. yield it and the names of the items
        #  we stored into the file
        with tarfile.open(tar_filename) as tarfl:
            yield tarfl, filename_1, dirname_1, filename_2

    @unittest.mock.patch('os.chown')
    @unittest.mock.patch('os.chmod')
    @unittest.mock.patch('os.geteuid')
    def test_extract_with_numeric_owner(self, mock_geteuid, mock_chmod,
                                        mock_chown):
        with self._setup_test(mock_geteuid) as (tarfl, filename_1, _,
                                                filename_2):
            tarfl.extract(filename_1, TEMPDIR, numeric_owner=True)
            tarfl.extract(filename_2 , TEMPDIR, numeric_owner=True)

        # convert to filesystem paths
        f_filename_1 = os.path.join(TEMPDIR, filename_1)
        f_filename_2 = os.path.join(TEMPDIR, filename_2)

        mock_chown.assert_has_calls([unittest.mock.call(f_filename_1, 99, 98),
                                     unittest.mock.call(f_filename_2, 88, 87),
                                     ],
                                    any_order=True)

    @unittest.mock.patch('os.chown')
    @unittest.mock.patch('os.chmod')
    @unittest.mock.patch('os.geteuid')
    def test_extractall_with_numeric_owner(self, mock_geteuid, mock_chmod,
                                           mock_chown):
        with self._setup_test(mock_geteuid) as (tarfl, filename_1, dirname_1,
                                                filename_2):
            tarfl.extractall(TEMPDIR, numeric_owner=True)

        # convert to filesystem paths
        f_filename_1 = os.path.join(TEMPDIR, filename_1)
        f_dirname_1  = os.path.join(TEMPDIR, dirname_1)
        f_filename_2 = os.path.join(TEMPDIR, filename_2)

        mock_chown.assert_has_calls([unittest.mock.call(f_filename_1, 99, 98),
                                     unittest.mock.call(f_dirname_1, 77, 76),
                                     unittest.mock.call(f_filename_2, 88, 87),
                                     ],
                                    any_order=True)

    # this test requires that uid=0 and gid=0 really be named 'root'. that's
    #  because the uname and gname in the test file are 'root', and extract()
    #  will look them up using pwd and grp to find their uid and gid, which we
    #  test here to be 0.
    @unittest.skipUnless(root_is_uid_gid_0(),
                         'uid=0,gid=0 must be named "root"')
    @unittest.mock.patch('os.chown')
    @unittest.mock.patch('os.chmod')
    @unittest.mock.patch('os.geteuid')
    def test_extract_without_numeric_owner(self, mock_geteuid, mock_chmod,
                                           mock_chown):
        with self._setup_test(mock_geteuid) as (tarfl, filename_1, _, _):
            tarfl.extract(filename_1, TEMPDIR, numeric_owner=False)

        # convert to filesystem paths
        f_filename_1 = os.path.join(TEMPDIR, filename_1)

        mock_chown.assert_called_with(f_filename_1, 0, 0)

    @unittest.mock.patch('os.geteuid')
    def test_keyword_only(self, mock_geteuid):
        with self._setup_test(mock_geteuid) as (tarfl, filename_1, _, _):
            self.assertRaises(TypeError,
                              tarfl.extract, filename_1, TEMPDIR, False, True)


def setUpModule():
    support.unlink(TEMPDIR)
    os.makedirs(TEMPDIR)

    global testtarnames
    testtarnames = [tarname]
    with open(tarname, "rb") as fobj:
        data = fobj.read()

    # Create compressed tarfiles.
    for c in GzipTest, Bz2Test, LzmaTest:
        if c.open:
            support.unlink(c.tarname)
            testtarnames.append(c.tarname)
            with c.open(c.tarname, "wb") as tar:
                tar.write(data)

def tearDownModule():
    if os.path.exists(TEMPDIR):
        support.rmtree(TEMPDIR)

if __name__ == "__main__":
    unittest.main()