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Patch #1484695: Update the tarfile module to version 0.8. This fixes 

a couple of issues, notably handling of long file names using the
GNU LONGNAME extension.
This commit is contained in:
Georg Brandl 2006-05-10 16:26:03 +00:00
parent f8d9a97ba2
commit 38c6a22f38
5 changed files with 254 additions and 181 deletions
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6
Doc/lib/libtarfile.tex
View File

@ -334,8 +334,12 @@ the file's data itself.
Create and return a \class{TarInfo} object from a string buffer.
\end{methoddesc}
\begin{methoddesc}{tobuf}{}
\begin{methoddesc}{tobuf}{posix}
Create a string buffer from a \class{TarInfo} object.
See \class{TarFile}'s \member{posix} attribute for information
on the \var{posix} argument. It defaults to \constant{False}.
\versionadded[The \var{posix} parameter]{2.5}
\end{methoddesc}
A \code{TarInfo} object has the following public data attributes:

332
Lib/tarfile.py
View File

@ -33,7 +33,7 @@
__version__ = "$Revision$"
# $Source$
version = "0.6.4"
version = "0.8.0"
__author__ = "Lars Gustäbel (lars@gustaebel.de)"
__date__ = "$Date$"
__cvsid__ = "$Id$"
@ -137,16 +137,64 @@ def nts(s):
"""
return s.rstrip(NUL)
def calc_chksum(buf):
"""Calculate the checksum for a member's header. It's a simple addition
of all bytes, treating the chksum field as if filled with spaces.
buf is a 512 byte long string buffer which holds the header.
def stn(s, length):
"""Convert a python string to a null-terminated string buffer.
"""
chk = 256 # chksum field is treated as blanks,
# so the initial value is 8 * ord(" ")
for c in buf[:148]: chk += ord(c) # sum up all bytes before chksum
for c in buf[156:]: chk += ord(c) # sum up all bytes after chksum
return chk
return struct.pack("%ds" % (length - 1), s) + NUL
def nti(s):
"""Convert a number field to a python number.
"""
# There are two possible encodings for a number field, see
# itn() below.
if s[0] != chr(0200):
n = int(s.rstrip(NUL) or "0", 8)
else:
n = 0L
for i in xrange(len(s) - 1):
n <<= 8
n += ord(s[i + 1])
return n
def itn(n, digits=8, posix=False):
"""Convert a python number to a number field.
"""
# POSIX 1003.1-1988 requires numbers to be encoded as a string of
# octal digits followed by a null-byte, this allows values up to
# (8**(digits-1))-1. GNU tar allows storing numbers greater than
# that if necessary. A leading 0200 byte indicates this particular
# encoding, the following digits-1 bytes are a big-endian
# representation. This allows values up to (256**(digits-1))-1.
if 0 <= n < 8 ** (digits - 1):
s = "%0*o" % (digits - 1, n) + NUL
else:
if posix:
raise ValueError, "overflow in number field"
if n < 0:
# XXX We mimic GNU tar's behaviour with negative numbers,
# this could raise OverflowError.
n = struct.unpack("L", struct.pack("l", n))[0]
s = ""
for i in xrange(digits - 1):
s = chr(n & 0377) + s
n >>= 8
s = chr(0200) + s
return s
def calc_chksums(buf):
"""Calculate the checksum for a member's header by summing up all
characters except for the chksum field which is treated as if
it was filled with spaces. According to the GNU tar sources,
some tars (Sun and NeXT) calculate chksum with signed char,
which will be different if there are chars in the buffer with
the high bit set. So we calculate two checksums, unsigned and
signed.
"""
unsigned_chksum = 256 + sum(struct.unpack("148B", buf[:148]) + struct.unpack("356B", buf[156:512]))
signed_chksum = 256 + sum(struct.unpack("148b", buf[:148]) + struct.unpack("356b", buf[156:512]))
return unsigned_chksum, signed_chksum
def copyfileobj(src, dst, length=None):
"""Copy length bytes from fileobj src to fileobj dst.
@ -655,7 +703,7 @@ class ExFileObject(object):
"""Get an iterator over the file object.
"""
if self.closed:
raise ValueError("I/O operation on closed file")
raise ValueError, "I/O operation on closed file"
return self
def next(self):
@ -695,9 +743,9 @@ class TarInfo(object):
self.linkname = "" # link name
self.uname = "user" # user name
self.gname = "group" # group name
self.devmajor = 0 #-
self.devminor = 0 #-for use with CHRTYPE and BLKTYPE
self.prefix = "" # prefix to filename or holding information
self.devmajor = 0 # device major number
self.devminor = 0 # device minor number
self.prefix = "" # prefix to filename or information
# about sparse files
self.offset = 0 # the tar header starts here
@ -710,95 +758,57 @@ class TarInfo(object):
def frombuf(cls, buf):
"""Construct a TarInfo object from a 512 byte string buffer.
"""
if len(buf) != BLOCKSIZE:
raise ValueError, "truncated header"
if buf.count(NUL) == BLOCKSIZE:
raise ValueError, "empty header"
tarinfo = cls()
tarinfo.buf = buf
tarinfo.name = nts(buf[0:100])
tarinfo.mode = int(buf[100:108], 8)
tarinfo.uid = int(buf[108:116],8)
tarinfo.gid = int(buf[116:124],8)
# There are two possible codings for the size field we
# have to discriminate, see comment in tobuf() below.
if buf[124] != chr(0200):
tarinfo.size = long(buf[124:136], 8)
else:
tarinfo.size = 0L
for i in range(11):
tarinfo.size <<= 8
tarinfo.size += ord(buf[125 + i])
tarinfo.mtime = long(buf[136:148], 8)
tarinfo.chksum = int(buf[148:156], 8)
tarinfo.mode = nti(buf[100:108])
tarinfo.uid = nti(buf[108:116])
tarinfo.gid = nti(buf[116:124])
tarinfo.size = nti(buf[124:136])
tarinfo.mtime = nti(buf[136:148])
tarinfo.chksum = nti(buf[148:156])
tarinfo.type = buf[156:157]
tarinfo.linkname = nts(buf[157:257])
tarinfo.uname = nts(buf[265:297])
tarinfo.gname = nts(buf[297:329])
try:
tarinfo.devmajor = int(buf[329:337], 8)
tarinfo.devminor = int(buf[337:345], 8)
except ValueError:
tarinfo.devmajor = tarinfo.devmajor = 0
tarinfo.devmajor = nti(buf[329:337])
tarinfo.devminor = nti(buf[337:345])
tarinfo.prefix = buf[345:500]
# Some old tar programs represent a directory as a regular
# file with a trailing slash.
if tarinfo.isreg() and tarinfo.name.endswith("/"):
tarinfo.type = DIRTYPE
# The prefix field is used for filenames > 100 in
# the POSIX standard.
# name = prefix + '/' + name
if tarinfo.type != GNUTYPE_SPARSE:
tarinfo.name = normpath(os.path.join(nts(tarinfo.prefix), tarinfo.name))
# Directory names should have a '/' at the end.
if tarinfo.isdir():
tarinfo.name += "/"
if tarinfo.chksum not in calc_chksums(buf):
raise ValueError, "invalid header"
return tarinfo
def tobuf(self):
def tobuf(self, posix=False):
"""Return a tar header block as a 512 byte string.
"""
# Prefer the size to be encoded as 11 octal ascii digits
# which is the most portable. If the size exceeds this
# limit (>= 8 GB), encode it as an 88-bit value which is
# a GNU tar feature.
if self.size <= MAXSIZE_MEMBER:
size = "%011o" % self.size
else:
s = self.size
size = ""
for i in range(11):
size = chr(s & 0377) + size
s >>= 8
size = chr(0200) + size
parts = [
stn(self.name, 100),
itn(self.mode & 07777, 8, posix),
itn(self.uid, 8, posix),
itn(self.gid, 8, posix),
itn(self.size, 12, posix),
itn(self.mtime, 12, posix),
" ", # checksum field
self.type,
stn(self.linkname, 100),
stn(MAGIC, 6),
stn(VERSION, 2),
stn(self.uname, 32),
stn(self.gname, 32),
itn(self.devmajor, 8, posix),
itn(self.devminor, 8, posix),
stn(self.prefix, 155)
]
# The following code was contributed by Detlef Lannert.
parts = []
for value, fieldsize in (
(self.name, 100),
("%07o" % (self.mode & 07777), 8),
("%07o" % self.uid, 8),
("%07o" % self.gid, 8),
(size, 12),
("%011o" % self.mtime, 12),
(" ", 8),
(self.type, 1),
(self.linkname, 100),
(MAGIC, 6),
(VERSION, 2),
(self.uname, 32),
(self.gname, 32),
("%07o" % self.devmajor, 8),
("%07o" % self.devminor, 8),
(self.prefix, 155)
):
l = len(value)
parts.append(value[:fieldsize] + (fieldsize - l) * NUL)
buf = "".join(parts)
chksum = calc_chksum(buf)
buf = struct.pack("%ds" % BLOCKSIZE, "".join(parts))
chksum = calc_chksums(buf)[0]
buf = buf[:148] + "%06o\0" % chksum + buf[155:]
buf += (BLOCKSIZE - len(buf)) * NUL
self.buf = buf
return buf
@ -1347,7 +1357,7 @@ class TarFile(object):
tarinfo.name = tarinfo.name[:LENGTH_NAME - 1]
self._dbg(2, "tarfile: Created GNU tar extension LONGNAME")
self.fileobj.write(tarinfo.tobuf())
self.fileobj.write(tarinfo.tobuf(self.posix))
self.offset += BLOCKSIZE
# If there's data to follow, append it.
@ -1660,7 +1670,6 @@ class TarFile(object):
raise ExtractError, "could not change modification time"
#--------------------------------------------------------------------------
def next(self):
"""Return the next member of the archive as a TarInfo object, when
TarFile is opened for reading. Return None if there is no more
@ -1678,32 +1687,9 @@ class TarFile(object):
buf = self.fileobj.read(BLOCKSIZE)
if not buf:
return None
try:
tarinfo = TarInfo.frombuf(buf)
except ValueError:
if self.ignore_zeros:
if buf.count(NUL) == BLOCKSIZE:
adj = "empty"
else:
adj = "invalid"
self._dbg(2, "0x%X: %s block" % (self.offset, adj))
self.offset += BLOCKSIZE
continue
else:
# Block is empty or unreadable.
if self.offset == 0:
# If the first block is invalid. That does not
# look like a tar archive we can handle.
raise ReadError,"empty, unreadable or compressed file"
return None
break
# We shouldn't rely on this checksum, because some tar programs
# calculate it differently and it is merely validating the
# header block. We could just as well skip this part, which would
# have a slight effect on performance...
if tarinfo.chksum != calc_chksum(buf):
self._dbg(1, "tarfile: Bad Checksum %r" % tarinfo.name)
# Set the TarInfo object's offset to the current position of the
# TarFile and set self.offset to the position where the data blocks
@ -1711,37 +1697,71 @@ class TarFile(object):
tarinfo.offset = self.offset
self.offset += BLOCKSIZE
# Check if the TarInfo object has a typeflag for which a callback
# method is registered in the TYPE_METH. If so, then call it.
if tarinfo.type in self.TYPE_METH:
return self.TYPE_METH[tarinfo.type](self, tarinfo)
tarinfo = self.proc_member(tarinfo)
tarinfo.offset_data = self.offset
if tarinfo.isreg() or tarinfo.type not in SUPPORTED_TYPES:
# Skip the following data blocks.
self.offset += self._block(tarinfo.size)
except ValueError, 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
break
# Some old tar programs represent a directory as a regular
# file with a trailing slash.
if tarinfo.isreg() and tarinfo.name.endswith("/"):
tarinfo.type = DIRTYPE
# The prefix field is used for filenames > 100 in
# the POSIX standard.
# name = prefix + '/' + name
tarinfo.name = normpath(os.path.join(nts(tarinfo.prefix), tarinfo.name))
# Directory names should have a '/' at the end.
if tarinfo.isdir():
tarinfo.name += "/"
self.members.append(tarinfo)
return tarinfo
#--------------------------------------------------------------------------
# Below are some methods which are called for special typeflags in the
# next() method, e.g. for unwrapping GNU longname/longlink blocks. They
# are registered in TYPE_METH below. You can register your own methods
# with this mapping.
# A registered method is called with a TarInfo object as only argument.
#
# During its execution the method MUST perform the following tasks:
# 1. set tarinfo.offset_data to the position where the data blocks begin,
# if there is data to follow.
# 2. set self.offset to the position where the next member's header will
# The following are methods that are called depending on the type of a
# member. The entry point is proc_member() which is called with a TarInfo
# object created from the header block from the current offset. The
# proc_member() method can be overridden in a subclass to add custom
# proc_*() methods. A proc_*() method MUST implement the following
# operations:
# 1. Set tarinfo.offset_data to the position where the data blocks begin,
# if there is data that follows.
# 2. Set self.offset to the position where the next member's header will
# begin.
# 3. append the tarinfo object to self.members, if it is supposed to appear
# as a member of the TarFile object.
# 4. return tarinfo or another valid TarInfo object.
# 3. Return tarinfo or another valid TarInfo object.
def proc_member(self, tarinfo):
"""Choose the right processing method for tarinfo depending
on its type and call it.
"""
if tarinfo.type in (GNUTYPE_LONGNAME, GNUTYPE_LONGLINK):
return self.proc_gnulong(tarinfo)
elif tarinfo.type == GNUTYPE_SPARSE:
return self.proc_sparse(tarinfo)
else:
return self.proc_builtin(tarinfo)
def proc_builtin(self, tarinfo):
"""Process a builtin type member or an unknown member
which will be treated as a regular file.
"""
tarinfo.offset_data = self.offset
if tarinfo.isreg() or tarinfo.type not in SUPPORTED_TYPES:
# Skip the following data blocks.
self.offset += self._block(tarinfo.size)
return tarinfo
def proc_gnulong(self, tarinfo):
"""Evaluate the blocks that hold a GNU longname
"""Process the blocks that hold a GNU longname
or longlink member.
"""
buf = ""
@ -1752,9 +1772,15 @@ class TarFile(object):
self.offset += BLOCKSIZE
count -= BLOCKSIZE
# Fetch the next header
next = self.next()
# Fetch the next header and process it.
b = self.fileobj.read(BLOCKSIZE)
t = TarInfo.frombuf(b)
t.offset = self.offset
self.offset += BLOCKSIZE
next = self.proc_member(t)
# Patch the TarInfo object from the next header with
# the longname information.
next.offset = tarinfo.offset
if tarinfo.type == GNUTYPE_LONGNAME:
next.name = nts(buf)
@ -1764,9 +1790,9 @@ class TarFile(object):
return next
def proc_sparse(self, tarinfo):
"""Analyze a GNU sparse header plus extra headers.
"""Process a GNU sparse header plus extra headers.
"""
buf = tarinfo.tobuf()
buf = tarinfo.buf
sp = _ringbuffer()
pos = 386
lastpos = 0L
@ -1775,8 +1801,8 @@ class TarFile(object):
# first header.
for i in xrange(4):
try:
offset = int(buf[pos:pos + 12], 8)
numbytes = int(buf[pos + 12:pos + 24], 8)
offset = nti(buf[pos:pos + 12])
numbytes = nti(buf[pos + 12:pos + 24])
except ValueError:
break
if offset > lastpos:
@ -1787,7 +1813,7 @@ class TarFile(object):
pos += 24
isextended = ord(buf[482])
origsize = int(buf[483:495], 8)
origsize = nti(buf[483:495])
# If the isextended flag is given,
# there are extra headers to process.
@ -1797,8 +1823,8 @@ class TarFile(object):
pos = 0
for i in xrange(21):
try:
offset = int(buf[pos:pos + 12], 8)
numbytes = int(buf[pos + 12:pos + 24], 8)
offset = nti(buf[pos:pos + 12])
numbytes = nti(buf[pos + 12:pos + 24])
except ValueError:
break
if offset > lastpos:
@ -1818,17 +1844,11 @@ class TarFile(object):
self.offset += self._block(tarinfo.size)
tarinfo.size = origsize
self.members.append(tarinfo)
return tarinfo
# Clear the prefix field so that it is not used
# as a pathname in next().
tarinfo.prefix = ""
# The type mapping for the next() method. The keys are single character
# strings, the typeflag. The values are methods which are called when
# next() encounters such a typeflag.
TYPE_METH = {
GNUTYPE_LONGNAME: proc_gnulong,
GNUTYPE_LONGLINK: proc_gnulong,
GNUTYPE_SPARSE: proc_sparse
}
return tarinfo
#--------------------------------------------------------------------------
# Little helper methods:

49
Lib/test/test_tarfile.py
View File

@ -2,6 +2,7 @@ import sys
import os
import shutil
import tempfile
import StringIO
import unittest
import tarfile
@ -25,7 +26,7 @@ def path(path):
testtar = path("testtar.tar")
tempdir = os.path.join(tempfile.gettempdir(), "testtar" + os.extsep + "dir")
tempname = test_support.TESTFN
membercount = 10
membercount = 12
def tarname(comp=""):
if not comp:
@ -254,7 +255,7 @@ class WriteTest(BaseTest):
if not tarinfo.isreg():
continue
f = self.src.extractfile(tarinfo)
if self.dst.posix and len(tarinfo.name) > tarfile.LENGTH_NAME:
if self.dst.posix and len(tarinfo.name) > tarfile.LENGTH_NAME and "/" not in tarinfo.name:
self.assertRaises(ValueError, self.dst.addfile,
tarinfo, f)
else:
@ -385,6 +386,49 @@ class WriteGNULongTest(unittest.TestCase):
self._test(("longnam/" * 127) + "longname_",
("longlnk/" * 127) + "longlink_")
class ReadGNULongTest(unittest.TestCase):
def setUp(self):
self.tar = tarfile.open(tarname())
def tearDown(self):
self.tar.close()
def test_1471427(self):
"""Test reading of longname (bug #1471427).
"""
name = "test/" * 20 + "0-REGTYPE"
try:
tarinfo = self.tar.getmember(name)
except KeyError:
tarinfo = None
self.assert_(tarinfo is not None, "longname not found")
self.assert_(tarinfo.type != tarfile.DIRTYPE, "read longname as dirtype")
def test_read_name(self):
name = ("0-LONGNAME-" * 10)[:101]
try:
tarinfo = self.tar.getmember(name)
except KeyError:
tarinfo = None
self.assert_(tarinfo is not None, "longname not found")
def test_read_link(self):
link = ("1-LONGLINK-" * 10)[:101]
name = ("0-LONGNAME-" * 10)[:101]
try:
tarinfo = self.tar.getmember(link)
except KeyError:
tarinfo = None
self.assert_(tarinfo is not None, "longlink not found")
self.assert_(tarinfo.linkname == name, "linkname wrong")
def test_truncated_longname(self):
fobj = StringIO.StringIO(file(tarname()).read(1024))
tar = tarfile.open(name="foo.tar", fileobj=fobj)
self.assert_(len(tar.getmembers()) == 0, "")
class ExtractHardlinkTest(BaseTest):
def test_hardlink(self):
@ -512,6 +556,7 @@ def test_main():
WriteSize0Test,
WriteStreamTest,
WriteGNULongTest,
ReadGNULongTest,
]
if hasattr(os, "link"):

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Lib/test/testtar.tar
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4
Misc/NEWS
View File

@ -96,6 +96,10 @@ Extension Modules
Library
-------
- Patch #1484695: Update the tarfile module to version 0.8. This fixes
a couple of issues, notably handling of long file names using the
GNU LONGNAME extension.
- Patch #1478292. ``doctest.register_optionflag(name)`` shouldn't create a
new flag when ``name`` is already the name of an option flag.