Lib/test/test_tarfile.py

import sys
import os
import io
import shutil
import tempfile
import io
from hashlib import md5
import errno

import unittest
import tarfile

from test import support

# Check for our compression modules.
try:
    import gzip
    gzip.GzipFile
except (ImportError, AttributeError):
    gzip = None
try:
    import bz2
except ImportError:
    bz2 = None

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

def path(path):
    return support.findfile(path)

TEMPDIR = os.path.join(tempfile.gettempdir(), "test_tarfile_tmp")
tarname = path("testtar.tar")
gzipname = os.path.join(TEMPDIR, "testtar.tar.gz")
bz2name = os.path.join(TEMPDIR, "testtar.tar.bz2")
tmpname = os.path.join(TEMPDIR, "tmp.tar")

md5_regtype = "65f477c818ad9e15f7feab0c6d37742f"
md5_sparse = "a54fbc4ca4f4399a90e1b27164012fc6"


class ReadTest(unittest.TestCase):

    tarname = tarname
    mode = "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):

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

    def test_fileobj_readlines(self):
        self.tar.extract("ustar/regtype", TEMPDIR)
        tarinfo = self.tar.getmember("ustar/regtype")
        fobj1 = open(os.path.join(TEMPDIR, "ustar/regtype"), "r")
        fobj2 = io.TextIOWrapper(self.tar.extractfile(tarinfo))

        lines1 = fobj1.readlines()
        lines2 = fobj2.readlines()
        self.assert_(lines1 == lines2,
                "fileobj.readlines() failed")
        self.assert_(len(lines2) == 114,
                "fileobj.readlines() failed")
        self.assert_(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")
        fobj1 = open(os.path.join(TEMPDIR, "ustar/regtype"), "rU")
        fobj2 = self.tar.extractfile(tarinfo)
        lines1 = fobj1.readlines()
        lines2 = list(io.TextIOWrapper(fobj2))
        self.assert_(lines1 == lines2,
                     "fileobj.__iter__() failed")

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

        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.assert_(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.assert_(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.assert_(s1 == s2,
                     "readlines() after seek failed")
        fobj.seek(0)
        self.assertEqual(len(fobj.readline()), fobj.tell(),
                     "tell() after readline() failed")
        fobj.seek(512)
        self.assert_(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()


class MiscReadTest(ReadTest):

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

    def test_no_name_attribute(self):
        data = open(self.tarname, "rb").read()
        fobj = io.BytesIO(data)
        self.assertRaises(AttributeError, getattr, fobj, "name")
        tar = tarfile.open(fileobj=fobj, mode=self.mode)
        self.assertEqual(tar.name, None)

    def test_empty_name_attribute(self):
        data = open(self.tarname, "rb").read()
        fobj = io.BytesIO(data)
        fobj.name = ""
        tar = tarfile.open(fileobj=fobj, mode=self.mode)
        self.assertEqual(tar.name, None)

    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)
        tar.next()
        t = tar.next()
        name = t.name
        offset = t.offset
        data = tar.extractfile(t).read()
        tar.close()

        # Open the testtar and seek to the offset of the second member.
        if self.mode.endswith(":gz"):
            _open = gzip.GzipFile
        elif self.mode.endswith(":bz2"):
            _open = bz2.BZ2File
        else:
            _open = open
        fobj = _open(self.tarname, "rb")
        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.
        if self.mode == "r:":
            return
        self.assertRaises(tarfile.ReadError, tarfile.open, tarname, self.mode)
        fobj = open(tarname, "rb")
        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.assert_(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.assert_(int(tarinfo.mtime) == 0o7606136617,
                    "wrong mtime for %s" % tarinfo.name)
            if not tarinfo.name.startswith("ustar/"):
                continue
            self.assert_(tarinfo.uname == "tarfile",
                    "wrong uname for %s" % tarinfo.name)

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

    def test_extract_hardlink(self):
        # Test hardlink extraction (e.g. bug #857297).
        tar = tarfile.open(tarname, errorlevel=1, encoding="iso8859-1")

        tar.extract("ustar/regtype", TEMPDIR)
        try:
            tar.extract("ustar/lnktype", TEMPDIR)
        except EnvironmentError as e:
            if e.errno == errno.ENOENT:
                self.fail("hardlink not extracted properly")

        data = open(os.path.join(TEMPDIR, "ustar/lnktype"), "rb").read()
        self.assertEqual(md5sum(data), md5_regtype)

        try:
            tar.extract("ustar/symtype", TEMPDIR)
        except EnvironmentError as e:
            if e.errno == errno.ENOENT:
                self.fail("symlink not extracted properly")

        data = open(os.path.join(TEMPDIR, "ustar/symtype"), "rb").read()
        self.assertEqual(md5sum(data), md5_regtype)

    def test_extractall(self):
        # Test if extractall() correctly restores directory permissions
        # and times (see issue1735).
        if sys.platform == "win32":
            # Win32 has no support for utime() on directories or
            # fine grained permissions.
            return

        tar = tarfile.open(tarname, encoding="iso8859-1")
        directories = [t for t in tar if t.isdir()]
        tar.extractall(TEMPDIR, directories)
        for tarinfo in directories:
            path = os.path.join(TEMPDIR, tarinfo.name)
            self.assertEqual(tarinfo.mode & 0o777, os.stat(path).st_mode & 0o777)
            self.assertEqual(tarinfo.mtime, os.path.getmtime(path))
        tar.close()


class StreamReadTest(ReadTest):

    mode="r|"

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

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

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

        while True:
            t1 = tar1.next()
            t2 = tar2.next()
            if t1 is None:
                break
            self.assert_(t2 is not None, "stream.next() failed.")

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

            v1 = tar1.extractfile(t1)
            v2 = tar2.extractfile(t2)
            if v1 is None:
                continue
            self.assert_(v2 is not None, "stream.extractfile() failed")
            self.assertEqual(v1.read(), v2.read(), "stream extraction failed")

        tar1.close()


class DetectReadTest(unittest.TestCase):

    def _testfunc_file(self, name, mode):
        try:
            tarfile.open(name, mode)
        except tarfile.ReadError as e:
            self.fail()

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

    def _test_modes(self, testfunc):
        testfunc(tarname, "r")
        testfunc(tarname, "r:")
        testfunc(tarname, "r:*")
        testfunc(tarname, "r|")
        testfunc(tarname, "r|*")

        if gzip:
            self.assertRaises(tarfile.ReadError, tarfile.open, tarname, mode="r:gz")
            self.assertRaises(tarfile.ReadError, tarfile.open, tarname, mode="r|gz")
            self.assertRaises(tarfile.ReadError, tarfile.open, gzipname, mode="r:")
            self.assertRaises(tarfile.ReadError, tarfile.open, gzipname, mode="r|")

            testfunc(gzipname, "r")
            testfunc(gzipname, "r:*")
            testfunc(gzipname, "r:gz")
            testfunc(gzipname, "r|*")
            testfunc(gzipname, "r|gz")

        if bz2:
            self.assertRaises(tarfile.ReadError, tarfile.open, tarname, mode="r:bz2")
            self.assertRaises(tarfile.ReadError, tarfile.open, tarname, mode="r|bz2")
            self.assertRaises(tarfile.ReadError, tarfile.open, bz2name, mode="r:")
            self.assertRaises(tarfile.ReadError, tarfile.open, bz2name, mode="r|")

            testfunc(bz2name, "r")
            testfunc(bz2name, "r:*")
            testfunc(bz2name, "r:bz2")
            testfunc(bz2name, "r|*")
            testfunc(bz2name, "r|bz2")

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

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


class MemberReadTest(ReadTest):

    def _test_member(self, tarinfo, chksum=None, **kwargs):
        if chksum is not None:
            self.assert_(md5sum(self.tar.extractfile(tarinfo).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.assert_(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_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.assert_(name in 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 = 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(ReadTest):

    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.assert_(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.assert_(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))
        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
        fobj = open(tarname, "rb")
        fobj.seek(offset)
        tarinfo = tarfile.TarInfo.frombuf(fobj.read(512), "iso8859-1", "strict")
        self.assertEqual(tarinfo.type, self.longnametype)


class GNUReadTest(LongnameTest):

    subdir = "gnu"
    longnametype = tarfile.GNUTYPE_LONGNAME

    def test_sparse_file(self):
        tarinfo1 = self.tar.getmember("ustar/sparse")
        fobj1 = self.tar.extractfile(tarinfo1)
        tarinfo2 = self.tar.getmember("gnu/sparse")
        fobj2 = self.tar.extractfile(tarinfo2)
        self.assertEqual(fobj1.read(), fobj2.read(),
                "sparse file extraction failed")


class PaxReadTest(LongnameTest):

    subdir = "pax"
    longnametype = tarfile.XHDTYPE

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

        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")

    def test_pax_number_fields(self):
        # All following number fields are read from the pax header.
        tar = tarfile.open(tarname, encoding="iso8859-1")
        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)


class WriteTest(unittest.TestCase):

    mode = "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)
        t = tarfile.TarInfo(name)
        tar.addfile(t)
        tar.close()

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

    def test_tar_size(self):
        # Test for bug #1013882.
        tar = tarfile.open(tmpname, self.mode)
        path = os.path.join(TEMPDIR, "file")
        fobj = open(path, "wb")
        fobj.write(b"aaa")
        fobj.close()
        tar.add(path)
        tar.close()
        self.assert_(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)

        path = os.path.join(TEMPDIR, "file")
        fobj = open(path, "wb")
        fobj.close()
        tarinfo = tar.gettarinfo(path)
        self.assertEqual(tarinfo.size, 0)

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

        tar.close()

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

    def test_link_size(self):
        if hasattr(os, "link"):
            link = os.path.join(TEMPDIR, "link")
            target = os.path.join(TEMPDIR, "link_target")
            open(target, "wb").close()
            os.link(target, link)
            try:
                tar = tarfile.open(tmpname, self.mode)
                tarinfo = tar.gettarinfo(link)
                self.assertEqual(tarinfo.size, 0)
            finally:
                os.remove(target)
                os.remove(link)

    def test_symlink_size(self):
        if hasattr(os, "symlink"):
            path = os.path.join(TEMPDIR, "symlink")
            os.symlink("link_target", path)
            try:
                tar = tarfile.open(tmpname, self.mode)
                tarinfo = tar.gettarinfo(path)
                self.assertEqual(tarinfo.size, 0)
            finally:
                os.remove(path)

    def test_add_self(self):
        # Test for #1257255.
        dstname = os.path.abspath(tmpname)

        tar = tarfile.open(tmpname, self.mode)
        self.assert_(tar.name == dstname, "archive name must be absolute")

        tar.add(dstname)
        self.assert_(tar.getnames() == [], "added the archive to itself")

        cwd = os.getcwd()
        os.chdir(TEMPDIR)
        tar.add(dstname)
        os.chdir(cwd)
        self.assert_(tar.getnames() == [], "added the archive to itself")

    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)
                open(name, "wb").close()

            def exclude(name):
                return os.path.isfile(name)

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

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


class StreamWriteTest(unittest.TestCase):

    mode = "w|"

    def test_stream_padding(self):
        # Test for bug #1543303.
        tar = tarfile.open(tmpname, self.mode)
        tar.close()

        if self.mode.endswith("gz"):
            fobj = gzip.GzipFile(tmpname)
            data = fobj.read()
            fobj.close()
        elif self.mode.endswith("bz2"):
            dec = bz2.BZ2Decompressor()
            data = open(tmpname, "rb").read()
            data = dec.decompress(data)
            self.assert_(len(dec.unused_data) == 0,
                    "found trailing data")
        else:
            fobj = open(tmpname, "rb")
            data = fobj.read()
            fobj.close()

        self.assert_(data.count(b"\0") == tarfile.RECORDSIZE,
                         "incorrect zero padding")


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, remainder = divmod(len(s) + 1, 512)
        if remainder:
            blocks += 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")
        tar.format = tarfile.GNU_FORMAT
        tar.addfile(tarinfo)

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

        tar.close()

        tar = tarfile.open(tmpname)
        member = tar.next()
        self.failIf(member is None, "unable to read longname member")
        self.assert_(tarinfo.name == member.name and \
                     tarinfo.linkname == member.linkname, \
                     "unable to read longname member")

    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 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")

        fobj = open(self.foo, "wb")
        fobj.write(b"foo")
        fobj.close()

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

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

    def tearDown(self):
        os.remove(self.foo)
        os.remove(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.assert_(tarinfo.type == tarfile.REGTYPE,
                "add file as regular failed")

    def test_add_hardlink(self):
        tarinfo = self.tar.gettarinfo(self.bar)
        self.assert_(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.assert_(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)
        tar.addfile(tarinfo)
        tar.close()

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

    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)
        tar.addfile(tarfile.TarInfo("test"))
        tar.close()

        # Test if the global header was written correctly.
        tar = tarfile.open(tmpname, encoding="iso8859-1")
        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.assert_(type(key) is not bytes)
            self.assert_(type(val) is not 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")

    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")
        t = tarfile.TarInfo()
        t.name = "\xe4\xf6\xfc" # non-ASCII
        t.uid = 8**8 # too large
        t.pax_headers = pax_headers
        tar.addfile(t)
        tar.close()

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


class UstarUnicodeTest(unittest.TestCase):

    format = tarfile.USTAR_FORMAT

    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("utf8")

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

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

    def test_unicode_filename_error(self):
        if self.format == tarfile.PAX_FORMAT:
            # PAX_FORMAT ignores encoding in write mode.
            return

        tar = tarfile.open(tmpname, "w", format=self.format, encoding="ascii", errors="strict")
        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)

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

        tar = tarfile.open(tmpname, encoding="iso8859-1")
        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 = tarfile.open(tmpname, encoding="ascii")
            t = tar.getmember("foo")
            self.assertEqual(t.uname, "\ufffd\ufffd\ufffd")
            self.assertEqual(t.gname, "\ufffd\ufffd\ufffd")


class GNUUnicodeTest(UstarUnicodeTest):

    format = tarfile.GNU_FORMAT


class PAXUnicodeTest(UstarUnicodeTest):

    format = tarfile.PAX_FORMAT


class AppendTest(unittest.TestCase):
    # Test append mode (cp. patch #1652681).

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

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

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

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

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

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

    def test_empty_fileobj(self):
        fobj = io.BytesIO()
        self._add_testfile(fobj)
        fobj.seek(0)
        self._test(fileobj=fobj)

    def test_fileobj(self):
        self._create_testtar()
        data = open(self.tarname, "rb").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"])

    def test_append_gz(self):
        if gzip is None:
            return
        self._create_testtar("w:gz")
        self.assertRaises(tarfile.ReadError, tarfile.open, tmpname, "a")

    def test_append_bz2(self):
        if bz2 is None:
            return
        self._create_testtar("w:bz2")
        self.assertRaises(tarfile.ReadError, tarfile.open, tmpname, "a")


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_number_fields(self):
        self.assertEqual(tarfile.itn(1), b"0000001\x00")
        self.assertEqual(tarfile.itn(0xffffffff), b"\x80\x00\x00\x00\xff\xff\xff\xff")


class GzipMiscReadTest(MiscReadTest):
    tarname = gzipname
    mode = "r:gz"
class GzipUstarReadTest(UstarReadTest):
    tarname = gzipname
    mode = "r:gz"
class GzipStreamReadTest(StreamReadTest):
    tarname = gzipname
    mode = "r|gz"
class GzipWriteTest(WriteTest):
    mode = "w:gz"
class GzipStreamWriteTest(StreamWriteTest):
    mode = "w|gz"


class Bz2MiscReadTest(MiscReadTest):
    tarname = bz2name
    mode = "r:bz2"
class Bz2UstarReadTest(UstarReadTest):
    tarname = bz2name
    mode = "r:bz2"
class Bz2StreamReadTest(StreamReadTest):
    tarname = bz2name
    mode = "r|bz2"
class Bz2WriteTest(WriteTest):
    mode = "w:bz2"
class Bz2StreamWriteTest(StreamWriteTest):
    mode = "w|bz2"

def test_main():
    if not os.path.exists(TEMPDIR):
        os.mkdir(TEMPDIR)

    tests = [
        UstarReadTest,
        MiscReadTest,
        StreamReadTest,
        DetectReadTest,
        MemberReadTest,
        GNUReadTest,
        PaxReadTest,
        WriteTest,
        StreamWriteTest,
        GNUWriteTest,
        PaxWriteTest,
        UstarUnicodeTest,
        GNUUnicodeTest,
        PAXUnicodeTest,
        AppendTest,
        LimitsTest,
        MiscTest,
    ]

    if hasattr(os, "link"):
        tests.append(HardlinkTest)

    fobj = open(tarname, "rb")
    data = fobj.read()
    fobj.close()

    if gzip:
        # Create testtar.tar.gz and add gzip-specific tests.
        tar = gzip.open(gzipname, "wb")
        tar.write(data)
        tar.close()

        tests += [
            GzipMiscReadTest,
            GzipUstarReadTest,
            GzipStreamReadTest,
            GzipWriteTest,
            GzipStreamWriteTest,
        ]

    if bz2:
        # Create testtar.tar.bz2 and add bz2-specific tests.
        tar = bz2.BZ2File(bz2name, "wb")
        tar.write(data)
        tar.close()

        tests += [
            Bz2MiscReadTest,
            Bz2UstarReadTest,
            Bz2StreamReadTest,
            Bz2WriteTest,
            Bz2StreamWriteTest,
        ]

    try:
        support.run_unittest(*tests)
    finally:
        if os.path.exists(TEMPDIR):
            shutil.rmtree(TEMPDIR)

if __name__ == "__main__":
    test_main()