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Copy pathtarfile.py
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executable file
·2576 lines (2247 loc) · 91.9 KB
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#!/usr/bin/env python3
#-------------------------------------------------------------------
# tarfile.py
#-------------------------------------------------------------------
# Copyright (C) 2002 Lars Gustaebel <lars@gustaebel.de>
# All rights reserved.
#
# Permission is hereby granted, free of charge, to any person
# obtaining a copy of this software and associated documentation
# files (the "Software"), to deal in the Software without
# restriction, including without limitation the rights to use,
# copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the
# Software is furnished to do so, subject to the following
# conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
# OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
# HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
# WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
# OTHER DEALINGS IN THE SOFTWARE.
#
"""Read from and write to tar format archives.
"""
version = "0.9.0"
__author__ = "Lars Gust\u00e4bel (lars@gustaebel.de)"
__credits__ = "Gustavo Niemeyer, Niels Gust\u00e4bel, Richard Townsend."
#---------
# Imports
#---------
from builtins import open as bltn_open
import sys
import os
import io
import shutil
import stat
import time
import struct
import copy
import re
try:
import pwd
except ImportError:
pwd = None
try:
import grp
except ImportError:
grp = None
# os.symlink on Windows prior to 6.0 raises NotImplementedError
symlink_exception = (AttributeError, NotImplementedError)
try:
# OSError (winerror=1314) will be raised if the caller does not hold the
# SeCreateSymbolicLinkPrivilege privilege
symlink_exception += (OSError,)
except NameError:
pass
# from tarfile import *
__all__ = ["TarFile", "TarInfo", "is_tarfile", "TarError", "ReadError",
"CompressionError", "StreamError", "ExtractError", "HeaderError",
"ENCODING", "USTAR_FORMAT", "GNU_FORMAT", "PAX_FORMAT",
"DEFAULT_FORMAT", "open"]
#---------------------------------------------------------
# tar constants
#---------------------------------------------------------
NUL = b"\0" # the null character
BLOCKSIZE = 512 # length of processing blocks
RECORDSIZE = BLOCKSIZE * 20 # length of records
GNU_MAGIC = b"ustar \0" # magic gnu tar string
POSIX_MAGIC = b"ustar\x0000" # magic posix tar string
LENGTH_NAME = 100 # maximum length of a filename
LENGTH_LINK = 100 # maximum length of a linkname
LENGTH_PREFIX = 155 # maximum length of the prefix field
REGTYPE = b"0" # regular file
AREGTYPE = b"\0" # regular file
LNKTYPE = b"1" # link (inside tarfile)
SYMTYPE = b"2" # symbolic link
CHRTYPE = b"3" # character special device
BLKTYPE = b"4" # block special device
DIRTYPE = b"5" # directory
FIFOTYPE = b"6" # fifo special device
CONTTYPE = b"7" # contiguous file
GNUTYPE_LONGNAME = b"L" # GNU tar longname
GNUTYPE_LONGLINK = b"K" # GNU tar longlink
GNUTYPE_SPARSE = b"S" # GNU tar sparse file
XHDTYPE = b"x" # POSIX.1-2001 extended header
XGLTYPE = b"g" # POSIX.1-2001 global header
SOLARIS_XHDTYPE = b"X" # Solaris extended header
USTAR_FORMAT = 0 # POSIX.1-1988 (ustar) format
GNU_FORMAT = 1 # GNU tar format
PAX_FORMAT = 2 # POSIX.1-2001 (pax) format
DEFAULT_FORMAT = PAX_FORMAT
#---------------------------------------------------------
# tarfile constants
#---------------------------------------------------------
# File types that tarfile supports:
SUPPORTED_TYPES = (REGTYPE, AREGTYPE, LNKTYPE,
SYMTYPE, DIRTYPE, FIFOTYPE,
CONTTYPE, CHRTYPE, BLKTYPE,
GNUTYPE_LONGNAME, GNUTYPE_LONGLINK,
GNUTYPE_SPARSE)
# File types that will be treated as a regular file.
REGULAR_TYPES = (REGTYPE, AREGTYPE,
CONTTYPE, GNUTYPE_SPARSE)
# File types that are part of the GNU tar format.
GNU_TYPES = (GNUTYPE_LONGNAME, GNUTYPE_LONGLINK,
GNUTYPE_SPARSE)
# Fields from a pax header that override a TarInfo attribute.
PAX_FIELDS = ("path", "linkpath", "size", "mtime",
"uid", "gid", "uname", "gname")
# Fields from a pax header that are affected by hdrcharset.
PAX_NAME_FIELDS = {"path", "linkpath", "uname", "gname"}
# Fields in a pax header that are numbers, all other fields
# are treated as strings.
PAX_NUMBER_FIELDS = {
"atime": float,
"ctime": float,
"mtime": float,
"uid": int,
"gid": int,
"size": int
}
#---------------------------------------------------------
# initialization
#---------------------------------------------------------
if os.name == "nt":
ENCODING = "utf-8"
else:
ENCODING = sys.getfilesystemencoding()
#---------------------------------------------------------
# Some useful functions
#---------------------------------------------------------
def stn(s, length, encoding, errors):
"""Convert a string to a null-terminated bytes object.
"""
s = s.encode(encoding, errors)
return s[:length] + (length - len(s)) * NUL
def nts(s, encoding, errors):
"""Convert a null-terminated bytes object to a string.
"""
p = s.find(b"\0")
if p != -1:
s = s[:p]
return s.decode(encoding, errors)
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] in (0o200, 0o377):
n = 0
for i in range(len(s) - 1):
n <<= 8
n += s[i + 1]
if s[0] == 0o377:
n = -(256 ** (len(s) - 1) - n)
else:
try:
s = nts(s, "ascii", "strict")
n = int(s.strip() or "0", 8)
except ValueError:
raise InvalidHeaderError("invalid header")
return n
def itn(n, digits=8, format=DEFAULT_FORMAT):
"""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 0o200 or 0o377 byte indicate this
# particular encoding, the following digits-1 bytes are a big-endian
# base-256 representation. This allows values up to (256**(digits-1))-1.
# A 0o200 byte indicates a positive number, a 0o377 byte a negative
# number.
n = int(n)
if 0 <= n < 8 ** (digits - 1):
s = bytes("%0*o" % (digits - 1, n), "ascii") + NUL
elif format == GNU_FORMAT and -256 ** (digits - 1) <= n < 256 ** (digits - 1):
if n >= 0:
s = bytearray([0o200])
else:
s = bytearray([0o377])
n = 256 ** digits + n
for i in range(digits - 1):
s.insert(1, n & 0o377)
n >>= 8
else:
raise ValueError("overflow in number field")
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_from("148B8x356B", buf))
signed_chksum = 256 + sum(struct.unpack_from("148b8x356b", buf))
return unsigned_chksum, signed_chksum
def copyfileobj(src, dst, length=None, exception=OSError, bufsize=None):
"""Copy length bytes from fileobj src to fileobj dst.
If length is None, copy the entire content.
"""
bufsize = bufsize or 16 * 1024
if length == 0:
return
if length is None:
shutil.copyfileobj(src, dst, bufsize)
return
blocks, remainder = divmod(length, bufsize)
for b in range(blocks):
buf = src.read(bufsize)
if len(buf) < bufsize:
raise exception("unexpected end of data")
dst.write(buf)
if remainder != 0:
buf = src.read(remainder)
if len(buf) < remainder:
raise exception("unexpected end of data")
dst.write(buf)
return
def _safe_print(s):
encoding = getattr(sys.stdout, 'encoding', None)
if encoding is not None:
s = s.encode(encoding, 'backslashreplace').decode(encoding)
print(s, end=' ')
class TarError(Exception):
"""Base exception."""
pass
class ExtractError(TarError):
"""General exception for extract errors."""
pass
class ReadError(TarError):
"""Exception for unreadable tar archives."""
pass
class CompressionError(TarError):
"""Exception for unavailable compression methods."""
pass
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
#---------------------------
class _LowLevelFile:
"""Low-level file object. Supports reading and writing.
It is used instead of a regular file object for streaming
access.
"""
def __init__(self, name, mode):
mode = {
"r": os.O_RDONLY,
"w": os.O_WRONLY | os.O_CREAT | os.O_TRUNC,
}[mode]
if hasattr(os, "O_BINARY"):
mode |= os.O_BINARY
self.fd = os.open(name, mode, 0o666)
def close(self):
os.close(self.fd)
def read(self, size):
return os.read(self.fd, size)
def write(self, s):
os.write(self.fd, s)
class _Stream:
"""Class that serves as an adapter between TarFile and
a stream-like object. The stream-like object only
needs to have a read() or write() method and is accessed
blockwise. Use of gzip or bzip2 compression is possible.
A stream-like object could be for example: sys.stdin,
sys.stdout, a socket, a tape device etc.
_Stream is intended to be used only internally.
"""
def __init__(self, name, mode, comptype, fileobj, bufsize):
"""Construct a _Stream object.
"""
self._extfileobj = True
if fileobj is None:
fileobj = _LowLevelFile(name, mode)
self._extfileobj = False
if comptype == '*':
# Enable transparent compression detection for the
# stream interface
fileobj = _StreamProxy(fileobj)
comptype = fileobj.getcomptype()
self.name = name or ""
self.mode = mode
self.comptype = comptype
self.fileobj = fileobj
self.bufsize = bufsize
self.buf = b""
self.pos = 0
self.closed = False
try:
if comptype == "gz":
try:
import zlib
except ImportError:
raise CompressionError("zlib module is not available")
self.zlib = zlib
self.crc = zlib.crc32(b"")
if mode == "r":
self._init_read_gz()
self.exception = zlib.error
else:
self._init_write_gz()
elif comptype == "bz2":
try:
import bz2
except ImportError:
raise CompressionError("bz2 module is not available")
if mode == "r":
self.dbuf = b""
self.cmp = bz2.BZ2Decompressor()
self.exception = OSError
else:
self.cmp = bz2.BZ2Compressor()
elif comptype == "xz":
try:
import lzma
except ImportError:
raise CompressionError("lzma module is not available")
if mode == "r":
self.dbuf = b""
self.cmp = lzma.LZMADecompressor()
self.exception = lzma.LZMAError
else:
self.cmp = lzma.LZMACompressor()
elif comptype != "tar":
raise CompressionError("unknown compression type %r" % comptype)
except:
if not self._extfileobj:
self.fileobj.close()
self.closed = True
raise
def __del__(self):
if hasattr(self, "closed") and not self.closed:
self.close()
def _init_write_gz(self):
"""Initialize for writing with gzip compression.
"""
self.cmp = self.zlib.compressobj(9, self.zlib.DEFLATED,
-self.zlib.MAX_WBITS,
self.zlib.DEF_MEM_LEVEL,
0)
timestamp = struct.pack("<L", int(time.time()))
self.__write(b"\037\213\010\010" + timestamp + b"\002\377")
if self.name.endswith(".gz"):
self.name = self.name[:-3]
# RFC1952 says we must use ISO-8859-1 for the FNAME field.
self.__write(self.name.encode("iso-8859-1", "replace") + NUL)
def write(self, s):
"""Write string s to the stream.
"""
if self.comptype == "gz":
self.crc = self.zlib.crc32(s, self.crc)
self.pos += len(s)
if self.comptype != "tar":
s = self.cmp.compress(s)
self.__write(s)
def __write(self, s):
"""Write string s to the stream if a whole new block
is ready to be written.
"""
self.buf += s
while len(self.buf) > self.bufsize:
self.fileobj.write(self.buf[:self.bufsize])
self.buf = self.buf[self.bufsize:]
def close(self):
"""Close the _Stream object. No operation should be
done on it afterwards.
"""
if self.closed:
return
self.closed = True
try:
if self.mode == "w" and self.comptype != "tar":
self.buf += self.cmp.flush()
if self.mode == "w" and self.buf:
self.fileobj.write(self.buf)
self.buf = b""
if self.comptype == "gz":
self.fileobj.write(struct.pack("<L", self.crc))
self.fileobj.write(struct.pack("<L", self.pos & 0xffffFFFF))
finally:
if not self._extfileobj:
self.fileobj.close()
def _init_read_gz(self):
"""Initialize for reading a gzip compressed fileobj.
"""
self.cmp = self.zlib.decompressobj(-self.zlib.MAX_WBITS)
self.dbuf = b""
# taken from gzip.GzipFile with some alterations
if self.__read(2) != b"\037\213":
raise ReadError("not a gzip file")
if self.__read(1) != b"\010":
raise CompressionError("unsupported compression method")
flag = ord(self.__read(1))
self.__read(6)
if flag & 4:
xlen = ord(self.__read(1)) + 256 * ord(self.__read(1))
self.read(xlen)
if flag & 8:
while True:
s = self.__read(1)
if not s or s == NUL:
break
if flag & 16:
while True:
s = self.__read(1)
if not s or s == NUL:
break
if flag & 2:
self.__read(2)
def tell(self):
"""Return the stream's file pointer position.
"""
return self.pos
def seek(self, pos=0):
"""Set the stream's file pointer to pos. Negative seeking
is forbidden.
"""
if pos - self.pos >= 0:
blocks, remainder = divmod(pos - self.pos, self.bufsize)
for i in range(blocks):
self.read(self.bufsize)
self.read(remainder)
else:
raise StreamError("seeking backwards is not allowed")
return self.pos
def read(self, size):
"""Return the next size number of bytes from the stream."""
assert size is not None
buf = self._read(size)
self.pos += len(buf)
return buf
def _read(self, size):
"""Return size bytes from the stream.
"""
if self.comptype == "tar":
return self.__read(size)
c = len(self.dbuf)
t = [self.dbuf]
while c < size:
# Skip underlying buffer to avoid unaligned double buffering.
if self.buf:
buf = self.buf
self.buf = b""
else:
buf = self.fileobj.read(self.bufsize)
if not buf:
break
try:
buf = self.cmp.decompress(buf)
except self.exception:
raise ReadError("invalid compressed data")
t.append(buf)
c += len(buf)
t = b"".join(t)
self.dbuf = t[size:]
return t[:size]
def __read(self, size):
"""Return size bytes from stream. If internal buffer is empty,
read another block from the stream.
"""
c = len(self.buf)
t = [self.buf]
while c < size:
buf = self.fileobj.read(self.bufsize)
if not buf:
break
t.append(buf)
c += len(buf)
t = b"".join(t)
self.buf = t[size:]
return t[:size]
# class _Stream
class _StreamProxy(object):
"""Small proxy class that enables transparent compression
detection for the Stream interface (mode 'r|*').
"""
def __init__(self, fileobj):
self.fileobj = fileobj
self.buf = self.fileobj.read(BLOCKSIZE)
def read(self, size):
self.read = self.fileobj.read
return self.buf
def getcomptype(self):
if self.buf.startswith(b"\x1f\x8b\x08"):
return "gz"
elif self.buf[0:3] == b"BZh" and self.buf[4:10] == b"1AY&SY":
return "bz2"
elif self.buf.startswith((b"\x5d\x00\x00\x80", b"\xfd7zXZ")):
return "xz"
else:
return "tar"
def close(self):
self.fileobj.close()
# class StreamProxy
#------------------------
# Extraction file object
#------------------------
class _FileInFile(object):
"""A thin wrapper around an existing file object that
provides a part of its data as an individual file
object.
"""
def __init__(self, fileobj, offset, size, blockinfo=None):
self.fileobj = fileobj
self.offset = offset
self.size = size
self.position = 0
self.name = getattr(fileobj, "name", None)
self.closed = False
if blockinfo is None:
blockinfo = [(0, size)]
# Construct a map with data and zero blocks.
self.map_index = 0
self.map = []
lastpos = 0
realpos = self.offset
for offset, size in blockinfo:
if offset > lastpos:
self.map.append((False, lastpos, offset, None))
self.map.append((True, offset, offset + size, realpos))
realpos += size
lastpos = offset + size
if lastpos < self.size:
self.map.append((False, lastpos, self.size, None))
def flush(self):
pass
def readable(self):
return True
def writable(self):
return False
def seekable(self):
return self.fileobj.seekable()
def tell(self):
"""Return the current file position.
"""
return self.position
def seek(self, position, whence=io.SEEK_SET):
"""Seek to a position in the file.
"""
if whence == io.SEEK_SET:
self.position = min(max(position, 0), self.size)
elif whence == io.SEEK_CUR:
if position < 0:
self.position = max(self.position + position, 0)
else:
self.position = min(self.position + position, self.size)
elif whence == io.SEEK_END:
self.position = max(min(self.size + position, self.size), 0)
else:
raise ValueError("Invalid argument")
return self.position
def read(self, size=None):
"""Read data from the file.
"""
if size is None:
size = self.size - self.position
else:
size = min(size, self.size - self.position)
buf = b""
while size > 0:
while True:
data, start, stop, offset = self.map[self.map_index]
if start <= self.position < stop:
break
else:
self.map_index += 1
if self.map_index == len(self.map):
self.map_index = 0
length = min(size, stop - self.position)
if data:
self.fileobj.seek(offset + (self.position - start))
b = self.fileobj.read(length)
if len(b) != length:
raise ReadError("unexpected end of data")
buf += b
else:
buf += NUL * length
size -= length
self.position += length
return buf
def readinto(self, b):
buf = self.read(len(b))
b[:len(buf)] = buf
return len(buf)
def close(self):
self.closed = True
#class _FileInFile
class ExFileObject(io.BufferedReader):
def __init__(self, tarfile, tarinfo):
fileobj = _FileInFile(tarfile.fileobj, tarinfo.offset_data,
tarinfo.size, tarinfo.sparse)
super().__init__(fileobj)
#class ExFileObject
#------------------
# Exported Classes
#------------------
class TarInfo(object):
"""Informational class which holds the details about an
archive member given by a tar header block.
TarInfo objects are returned by TarFile.getmember(),
TarFile.getmembers() and TarFile.gettarinfo() and are
usually created internally.
"""
__slots__ = dict(
name = 'Name of the archive member.',
mode = 'Permission bits.',
uid = 'User ID of the user who originally stored this member.',
gid = 'Group ID of the user who originally stored this member.',
size = 'Size in bytes.',
mtime = 'Time of last modification.',
chksum = 'Header checksum.',
type = ('File type. type is usually one of these constants: '
'REGTYPE, AREGTYPE, LNKTYPE, SYMTYPE, DIRTYPE, FIFOTYPE, '
'CONTTYPE, CHRTYPE, BLKTYPE, GNUTYPE_SPARSE.'),
linkname = ('Name of the target file name, which is only present '
'in TarInfo objects of type LNKTYPE and SYMTYPE.'),
uname = 'User name.',
gname = 'Group name.',
devmajor = 'Device major number.',
devminor = 'Device minor number.',
offset = 'The tar header starts here.',
offset_data = "The file's data starts here.",
pax_headers = ('A dictionary containing key-value pairs of an '
'associated pax extended header.'),
sparse = 'Sparse member information.',
tarfile = None,
_sparse_structs = None,
_link_target = None,
)
def __init__(self, name=""):
"""Construct a TarInfo object. name is the optional name
of the member.
"""
self.name = name # member name
self.mode = 0o644 # file permissions
self.uid = 0 # user id
self.gid = 0 # group id
self.size = 0 # file size
self.mtime = 0 # modification time
self.chksum = 0 # header checksum
self.type = REGTYPE # member type
self.linkname = "" # link name
self.uname = "" # user name
self.gname = "" # group name
self.devmajor = 0 # device major number
self.devminor = 0 # device minor number
self.offset = 0 # the tar header starts here
self.offset_data = 0 # the file's data starts here
self.sparse = None # sparse member information
self.pax_headers = {} # pax header information
@property
def path(self):
'In pax headers, "name" is called "path".'
return self.name
@path.setter
def path(self, name):
self.name = name
@property
def linkpath(self):
'In pax headers, "linkname" is called "linkpath".'
return self.linkname
@linkpath.setter
def linkpath(self, linkname):
self.linkname = linkname
def __repr__(self):
return "<%s %r at %#x>" % (self.__class__.__name__,self.name,id(self))
def get_info(self):
"""Return the TarInfo's attributes as a dictionary.
"""
info = {
"name": self.name,
"mode": self.mode & 0o7777,
"uid": self.uid,
"gid": self.gid,
"size": self.size,
"mtime": self.mtime,
"chksum": self.chksum,
"type": self.type,
"linkname": self.linkname,
"uname": self.uname,
"gname": self.gname,
"devmajor": self.devmajor,
"devminor": self.devminor
}
if info["type"] == DIRTYPE and not info["name"].endswith("/"):
info["name"] += "/"
return info
def tobuf(self, format=DEFAULT_FORMAT, encoding=ENCODING, errors="surrogateescape"):
"""Return a tar header as a string of 512 byte blocks.
"""
info = self.get_info()
if format == USTAR_FORMAT:
return self.create_ustar_header(info, encoding, errors)
elif format == GNU_FORMAT:
return self.create_gnu_header(info, encoding, errors)
elif format == PAX_FORMAT:
return self.create_pax_header(info, encoding)
else:
raise ValueError("invalid format")
def create_ustar_header(self, info, encoding, errors):
"""Return the object as a ustar header block.
"""
info["magic"] = POSIX_MAGIC
if len(info["linkname"].encode(encoding, errors)) > LENGTH_LINK:
raise ValueError("linkname is too long")
if len(info["name"].encode(encoding, errors)) > LENGTH_NAME:
info["prefix"], info["name"] = self._posix_split_name(info["name"], encoding, errors)
return self._create_header(info, USTAR_FORMAT, encoding, errors)
def create_gnu_header(self, info, encoding, errors):
"""Return the object as a GNU header block sequence.
"""
info["magic"] = GNU_MAGIC
buf = b""
if len(info["linkname"].encode(encoding, errors)) > LENGTH_LINK:
buf += self._create_gnu_long_header(info["linkname"], GNUTYPE_LONGLINK, encoding, errors)
if len(info["name"].encode(encoding, errors)) > LENGTH_NAME:
buf += self._create_gnu_long_header(info["name"], GNUTYPE_LONGNAME, encoding, errors)
return buf + self._create_header(info, GNU_FORMAT, encoding, errors)
def create_pax_header(self, info, encoding):
"""Return the object as a ustar header block. If it cannot be
represented this way, prepend a pax extended header sequence
with supplement information.
"""
info["magic"] = POSIX_MAGIC
pax_headers = self.pax_headers.copy()
# Test string fields for values that exceed the field length or cannot
# be represented in ASCII encoding.
for name, hname, length in (
("name", "path", LENGTH_NAME), ("linkname", "linkpath", LENGTH_LINK),
("uname", "uname", 32), ("gname", "gname", 32)):
if hname in pax_headers:
# The pax header has priority.
continue
# Try to encode the string as ASCII.
try:
info[name].encode("ascii", "strict")
except UnicodeEncodeError:
pax_headers[hname] = info[name]
continue
if len(info[name]) > length:
pax_headers[hname] = info[name]
# Test number fields for values that exceed the field limit or values
# that like to be stored as float.
for name, digits in (("uid", 8), ("gid", 8), ("size", 12), ("mtime", 12)):
if name in pax_headers:
# The pax header has priority. Avoid overflow.
info[name] = 0
continue
val = info[name]
if not 0 <= val < 8 ** (digits - 1) or isinstance(val, float):
pax_headers[name] = str(val)
info[name] = 0
# Create a pax extended header if necessary.
if pax_headers:
buf = self._create_pax_generic_header(pax_headers, XHDTYPE, encoding)
else:
buf = b""
return buf + self._create_header(info, USTAR_FORMAT, "ascii", "replace")
@classmethod
def create_pax_global_header(cls, pax_headers):
"""Return the object as a pax global header block sequence.
"""
return cls._create_pax_generic_header(pax_headers, XGLTYPE, "utf-8")
def _posix_split_name(self, name, encoding, errors):
"""Split a name longer than 100 chars into a prefix
and a name part.
"""
components = name.split("/")
for i in range(1, len(components)):
prefix = "/".join(components[:i])
name = "/".join(components[i:])
if len(prefix.encode(encoding, errors)) <= LENGTH_PREFIX and \
len(name.encode(encoding, errors)) <= LENGTH_NAME:
break
else:
raise ValueError("name is too long")
return prefix, name
@staticmethod
def _create_header(info, format, encoding, errors):
"""Return a header block. info is a dictionary with file
information, format must be one of the *_FORMAT constants.
"""
has_device_fields = info.get("type") in (CHRTYPE, BLKTYPE)
if has_device_fields:
devmajor = itn(info.get("devmajor", 0), 8, format)
devminor = itn(info.get("devminor", 0), 8, format)
else:
devmajor = stn("", 8, encoding, errors)
devminor = stn("", 8, encoding, errors)
parts = [
stn(info.get("name", ""), 100, encoding, errors),
itn(info.get("mode", 0) & 0o7777, 8, format),
itn(info.get("uid", 0), 8, format),
itn(info.get("gid", 0), 8, format),
itn(info.get("size", 0), 12, format),
itn(info.get("mtime", 0), 12, format),
b" ", # checksum field
info.get("type", REGTYPE),
stn(info.get("linkname", ""), 100, encoding, errors),
info.get("magic", POSIX_MAGIC),
stn(info.get("uname", ""), 32, encoding, errors),
stn(info.get("gname", ""), 32, encoding, errors),
devmajor,
devminor,
stn(info.get("prefix", ""), 155, encoding, errors)
]
buf = struct.pack("%ds" % BLOCKSIZE, b"".join(parts))
chksum = calc_chksums(buf[-BLOCKSIZE:])[0]
buf = buf[:-364] + bytes("%06o\0" % chksum, "ascii") + buf[-357:]
return buf
@staticmethod
def _create_payload(payload):
"""Return the string payload filled with zero bytes
up to the next 512 byte border.
"""
blocks, remainder = divmod(len(payload), BLOCKSIZE)
if remainder > 0:
payload += (BLOCKSIZE - remainder) * NUL
return payload
@classmethod
def _create_gnu_long_header(cls, name, type, encoding, errors):
"""Return a GNUTYPE_LONGNAME or GNUTYPE_LONGLINK sequence
for name.
"""
name = name.encode(encoding, errors) + NUL
info = {}
info["name"] = "././@LongLink"
info["type"] = type
info["size"] = len(name)
info["magic"] = GNU_MAGIC
# create extended header + name blocks.
return cls._create_header(info, USTAR_FORMAT, encoding, errors) + \
cls._create_payload(name)
@classmethod
def _create_pax_generic_header(cls, pax_headers, type, encoding):
"""Return a POSIX.1-2008 extended or global header sequence
that contains a list of keyword, value pairs. The values
must be strings.
"""
# Check if one of the fields contains surrogate characters and thereby
# forces hdrcharset=BINARY, see _proc_pax() for more information.
binary = False
for keyword, value in pax_headers.items():