[Patch 988444]
Read multiple special headers - fixed/improved handling of extended/special headers in read-mode (adding new extended headers should be less painful now). - improved nts() function. - removed TarFile.chunks datastructure which is not (and was never) needed. - fixed TarInfo.tobuf(), fields could overflow with too large values, values are now clipped.
This commit is contained in:
Andrew M. Kuchling
parent
f027ca8167
commit
864bba1981
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@ -135,7 +135,7 @@ TOEXEC = 0001 # execute/search by other
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def nts(s):
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"""Convert a null-terminated string buffer to a python string.
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"""
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return s.split(NUL, 1)[0]
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return s.rstrip(NUL)
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def calc_chksum(buf):
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"""Calculate the checksum for a member's header. It's a simple addition
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@ -713,7 +713,7 @@ class TarInfo(object):
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(self.prefix, 155)
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):
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l = len(value)
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parts.append(value + (fieldsize - l) * NUL)
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parts.append(value[:fieldsize] + (fieldsize - l) * NUL)
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buf = "".join(parts)
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chksum = calc_chksum(buf)
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@ -796,7 +796,6 @@ class TarFile(object):
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self.closed = False
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self.members = [] # list of members as TarInfo objects
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self.membernames = [] # names of members
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self.chunks = [0] # chunk cache
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self._loaded = False # flag if all members have been read
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self.offset = 0L # current position in the archive file
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self.inodes = {} # dictionary caching the inodes of
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@ -1281,9 +1280,7 @@ class TarFile(object):
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blocks += 1
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self.offset += blocks * BLOCKSIZE
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self.members.append(tarinfo)
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self.membernames.append(tarinfo.name)
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self.chunks.append(self.offset)
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self._record_member(tarinfo)
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def extract(self, member, path=""):
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"""Extract a member from the archive to the current working directory,
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@ -1551,7 +1548,7 @@ class TarFile(object):
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return m
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# Read the next block.
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self.fileobj.seek(self.chunks[-1])
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self.fileobj.seek(self.offset)
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while True:
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buf = self.fileobj.read(BLOCKSIZE)
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if not buf:
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@ -1569,7 +1566,7 @@ class TarFile(object):
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continue
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else:
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# Block is empty or unreadable.
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if self.chunks[-1] == 0:
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if self.offset == 0:
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# If the first block is invalid. That does not
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# look like a tar archive we can handle.
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raise ReadError,"empty, unreadable or compressed file"
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@ -1592,8 +1589,8 @@ class TarFile(object):
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# Check if the TarInfo object has a typeflag for which a callback
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# method is registered in the TYPE_METH. If so, then call it.
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if tarinfo.type in self.TYPE_METH:
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tarinfo = self.TYPE_METH[tarinfo.type](self, tarinfo)
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else:
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return self.TYPE_METH[tarinfo.type](self, tarinfo)
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tarinfo.offset_data = self.offset
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if tarinfo.isreg() or tarinfo.type not in SUPPORTED_TYPES:
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# Skip the following data blocks.
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@ -1603,9 +1600,7 @@ class TarFile(object):
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# some old tar programs don't know DIRTYPE
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tarinfo.type = DIRTYPE
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self.members.append(tarinfo)
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self.membernames.append(tarinfo.name)
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self.chunks.append(self.offset)
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self._record_member(tarinfo)
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return tarinfo
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#--------------------------------------------------------------------------
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@ -1620,7 +1615,9 @@ class TarFile(object):
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# if there is data to follow.
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# 2. set self.offset to the position where the next member's header will
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# begin.
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# 3. return a valid TarInfo object.
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# 3. call self._record_member() if the tarinfo object is supposed to
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# appear as a member of the TarFile object.
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# 4. return tarinfo or another valid TarInfo object.
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def proc_gnulong(self, tarinfo):
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"""Evaluate the blocks that hold a GNU longname
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@ -1636,24 +1633,16 @@ class TarFile(object):
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self.offset += BLOCKSIZE
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count -= BLOCKSIZE
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# Fetch the next header
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next = self.next()
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next.offset = tarinfo.offset
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if tarinfo.type == GNUTYPE_LONGNAME:
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name = nts(buf)
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if tarinfo.type == GNUTYPE_LONGLINK:
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linkname = nts(buf)
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next.name = nts(buf)
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elif tarinfo.type == GNUTYPE_LONGLINK:
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next.linkname = nts(buf)
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buf = self.fileobj.read(BLOCKSIZE)
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tarinfo = TarInfo.frombuf(buf)
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tarinfo.offset = self.offset
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self.offset += BLOCKSIZE
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tarinfo.offset_data = self.offset
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tarinfo.name = name or tarinfo.name
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tarinfo.linkname = linkname or tarinfo.linkname
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if tarinfo.isreg() or tarinfo.type not in SUPPORTED_TYPES:
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# Skip the following data blocks.
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self.offset += self._block(tarinfo.size)
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return tarinfo
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return next
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def proc_sparse(self, tarinfo):
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"""Analyze a GNU sparse header plus extra headers.
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@ -1709,6 +1698,8 @@ class TarFile(object):
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tarinfo.offset_data = self.offset
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self.offset += self._block(tarinfo.size)
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tarinfo.size = origsize
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self._record_member(tarinfo)
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return tarinfo
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# The type mapping for the next() method. The keys are single character
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@ -1745,6 +1736,12 @@ class TarFile(object):
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if name == self.membernames[i]:
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return self.members[i]
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def _record_member(self, tarinfo):
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"""Record a tarinfo object in the internal datastructures.
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"""
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self.members.append(tarinfo)
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self.membernames.append(tarinfo.name)
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def _load(self):
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"""Read through the entire archive file and look for readable
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members.
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