diff options
| -rw-r--r-- | Lib/tarfile.py | 87 | ||||
| -rw-r--r-- | Lib/test/test_tarfile.py | 85 | ||||
| -rw-r--r-- | Misc/NEWS | 3 |
3 files changed, 143 insertions, 32 deletions
diff --git a/Lib/tarfile.py b/Lib/tarfile.py index 29e12f0216..f48b477bb6 100644 --- a/Lib/tarfile.py +++ b/Lib/tarfile.py @@ -195,7 +195,7 @@ def nti(s): try: n = int(nts(s) or "0", 8) except ValueError: - raise HeaderError("invalid header") + raise InvalidHeaderError("invalid header") else: n = 0L for i in xrange(len(s) - 1): @@ -346,8 +346,23 @@ class StreamError(TarError): """Exception for unsupported operations on stream-like TarFiles.""" pass class HeaderError(TarError): + """Base exception for header errors.""" + pass +class EmptyHeaderError(HeaderError): + """Exception for empty headers.""" + pass +class TruncatedHeaderError(HeaderError): + """Exception for truncated headers.""" + pass +class EOFHeaderError(HeaderError): + """Exception for end of file headers.""" + pass +class InvalidHeaderError(HeaderError): """Exception for invalid headers.""" pass +class SubsequentHeaderError(HeaderError): + """Exception for missing and invalid extended headers.""" + pass #--------------------------- # internal stream interface @@ -1179,14 +1194,16 @@ class TarInfo(object): def frombuf(cls, buf): """Construct a TarInfo object from a 512 byte string buffer. """ + if len(buf) == 0: + raise EmptyHeaderError("empty header") if len(buf) != BLOCKSIZE: - raise HeaderError("truncated header") + raise TruncatedHeaderError("truncated header") if buf.count(NUL) == BLOCKSIZE: - raise HeaderError("empty header") + raise EOFHeaderError("end of file header") chksum = nti(buf[148:156]) if chksum not in calc_chksums(buf): - raise HeaderError("bad checksum") + raise InvalidHeaderError("bad checksum") obj = cls() obj.buf = buf @@ -1225,8 +1242,6 @@ class TarInfo(object): tarfile. """ buf = tarfile.fileobj.read(BLOCKSIZE) - if not buf: - return obj = cls.frombuf(buf) obj.offset = tarfile.fileobj.tell() - BLOCKSIZE return obj._proc_member(tarfile) @@ -1279,9 +1294,10 @@ class TarInfo(object): buf = tarfile.fileobj.read(self._block(self.size)) # Fetch the next header and process it. - next = self.fromtarfile(tarfile) - if next is None: - raise HeaderError("missing subsequent header") + try: + next = self.fromtarfile(tarfile) + except HeaderError: + raise SubsequentHeaderError("missing or bad subsequent header") # Patch the TarInfo object from the next header with # the longname information. @@ -1386,12 +1402,12 @@ class TarInfo(object): pos += length # Fetch the next header. - next = self.fromtarfile(tarfile) + try: + next = self.fromtarfile(tarfile) + except HeaderError: + raise SubsequentHeaderError("missing or bad subsequent header") if self.type in (XHDTYPE, SOLARIS_XHDTYPE): - if next is None: - raise HeaderError("missing subsequent header") - # Patch the TarInfo object with the extended header info. next._apply_pax_info(pax_headers, tarfile.encoding, tarfile.errors) next.offset = self.offset @@ -1565,12 +1581,16 @@ class TarFile(object): if self.mode == "a": # Move to the end of the archive, # before the first empty block. - self.firstmember = None while True: - if self.next() is None: - if self.offset > 0: - self.fileobj.seek(- BLOCKSIZE, 1) + self.fileobj.seek(self.offset) + try: + tarinfo = self.tarinfo.fromtarfile(self) + self.members.append(tarinfo) + except EOFHeaderError: + self.fileobj.seek(self.offset) break + except HeaderError, e: + raise ReadError(str(e)) if self.mode in "aw": self._loaded = True @@ -1735,7 +1755,7 @@ class TarFile(object): try: t = cls.taropen(name, mode, fileobj, **kwargs) - except IOError: + except (IOError, EOFError): raise ReadError("not a bzip2 file") t._extfileobj = False return t @@ -2307,24 +2327,37 @@ class TarFile(object): # Read the next block. self.fileobj.seek(self.offset) + tarinfo = None while True: try: tarinfo = self.tarinfo.fromtarfile(self) - if tarinfo is None: - return - self.members.append(tarinfo) - - except HeaderError, e: + except EOFHeaderError, e: if self.ignore_zeros: self._dbg(2, "0x%X: %s" % (self.offset, e)) self.offset += BLOCKSIZE continue - else: - if self.offset == 0: - raise ReadError(str(e)) - return None + except InvalidHeaderError, e: + if self.ignore_zeros: + self._dbg(2, "0x%X: %s" % (self.offset, e)) + self.offset += BLOCKSIZE + continue + elif self.offset == 0: + raise ReadError(str(e)) + except EmptyHeaderError: + if self.offset == 0: + raise ReadError("empty file") + except TruncatedHeaderError, e: + if self.offset == 0: + raise ReadError(str(e)) + except SubsequentHeaderError, e: + raise ReadError(str(e)) break + if tarinfo is not None: + self.members.append(tarinfo) + else: + self._loaded = True + return tarinfo #-------------------------------------------------------------------------- diff --git a/Lib/test/test_tarfile.py b/Lib/test/test_tarfile.py index 74a8dac713..20339dd0a7 100644 --- a/Lib/test/test_tarfile.py +++ b/Lib/test/test_tarfile.py @@ -136,7 +136,53 @@ class UstarReadTest(ReadTest): fobj.close() -class MiscReadTest(ReadTest): +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! + tarfile.open(tmpname, self.mode.replace("r", "w")).close() + try: + tar = tarfile.open(tmpname, self.mode) + tar.getnames() + except tarfile.ReadError: + self.fail("tarfile.open() failed on empty archive") + self.assertListEqual(tar.getmembers(), []) + + 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. + open(tmpname, "wb").close() + 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. + if self.mode.endswith(":gz"): + _open = gzip.GzipFile + elif self.mode.endswith(":bz2"): + _open = bz2.BZ2File + else: + _open = open + + for char in ('\0', 'a'): + # Test if EOFHeaderError ('\0') and InvalidHeaderError ('a') + # are ignored correctly. + fobj = _open(tmpname, "wb") + fobj.write(char * 1024) + fobj.write(tarfile.TarInfo("foo").tobuf()) + fobj.close() + + tar = tarfile.open(tmpname, mode="r", ignore_zeros=True) + self.assertListEqual(tar.getnames(), ["foo"], + "ignore_zeros=True should have skipped the %r-blocks" % char) + tar.close() + + +class MiscReadTest(CommonReadTest): def test_no_name_argument(self): fobj = open(self.tarname, "rb") @@ -265,7 +311,7 @@ class MiscReadTest(ReadTest): tar.close() -class StreamReadTest(ReadTest): +class StreamReadTest(CommonReadTest): mode="r|" @@ -1111,12 +1157,12 @@ class AppendTest(unittest.TestCase): self._test() def test_empty(self): - open(self.tarname, "w").close() + tarfile.open(self.tarname, "w:").close() self._add_testfile() self._test() def test_empty_fileobj(self): - fobj = StringIO.StringIO() + fobj = StringIO.StringIO("\0" * 1024) self._add_testfile(fobj) fobj.seek(0) self._test(fileobj=fobj) @@ -1146,6 +1192,29 @@ class AppendTest(unittest.TestCase): self._create_testtar("w:bz2") self.assertRaises(tarfile.ReadError, tarfile.open, tmpname, "a") + # Append mode is supposed to fail if the tarfile to append to + # does not end with a zero block. + def _test_error(self, data): + open(self.tarname, "wb").write(data) + self.assertRaises(tarfile.ReadError, self._add_testfile) + + def test_null(self): + self._test_error("") + + def test_incomplete(self): + self._test_error("\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 + "\0" * 13) + + def test_invalid(self): + self._test_error("a" * 512) + class LimitsTest(unittest.TestCase): @@ -1247,10 +1316,16 @@ class Bz2PartialReadTest(unittest.TestCase): raise AssertionError("infinite loop detected in tarfile.open()") self.hit_eof = self.pos == self.len return StringIO.StringIO.read(self, n) + def seek(self, *args): + self.hit_eof = False + return StringIO.StringIO.seek(self, *args) data = bz2.compress(tarfile.TarInfo("foo").tobuf()) for x in range(len(data) + 1): - tarfile.open(fileobj=MyStringIO(data[:x]), mode=mode) + try: + tarfile.open(fileobj=MyStringIO(data[:x]), mode=mode) + except tarfile.ReadError: + pass # we have no interest in ReadErrors def test_partial_input(self): self._test_partial_input("r") @@ -476,6 +476,9 @@ Core and Builtins Library ------- +- Issue #6123: tarfile now opens empty archives correctly and consistently + raises ReadError on empty files. + - Issue #7354: distutils.tests.test_msvc9compiler - dragfullwindows can be 2. |