You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
483 lines
20 KiB
483 lines
20 KiB
# -*- coding: utf-8 -*-
|
|
# Copyright (c) 2005-2012 Stephen John Machin, Lingfo Pty Ltd
|
|
# This module is part of the xlrd package, which is released under a
|
|
# BSD-style licence.
|
|
# No part of the content of this file was derived from the works of
|
|
# David Giffin.
|
|
"""
|
|
Implements the minimal functionality required
|
|
to extract a "Workbook" or "Book" stream (as one big string)
|
|
from an OLE2 Compound Document file.
|
|
"""
|
|
from __future__ import print_function
|
|
|
|
import array
|
|
import sys
|
|
from struct import unpack
|
|
|
|
from .timemachine import *
|
|
|
|
#: Magic cookie that should appear in the first 8 bytes of the file.
|
|
SIGNATURE = b"\xD0\xCF\x11\xE0\xA1\xB1\x1A\xE1"
|
|
|
|
EOCSID = -2
|
|
FREESID = -1
|
|
SATSID = -3
|
|
MSATSID = -4
|
|
EVILSID = -5
|
|
|
|
class CompDocError(Exception):
|
|
pass
|
|
|
|
class DirNode(object):
|
|
|
|
def __init__(self, DID, dent, DEBUG=0, logfile=sys.stdout):
|
|
# dent is the 128-byte directory entry
|
|
self.DID = DID
|
|
self.logfile = logfile
|
|
(cbufsize, self.etype, self.colour, self.left_DID, self.right_DID,
|
|
self.root_DID) = \
|
|
unpack('<HBBiii', dent[64:80])
|
|
(self.first_SID, self.tot_size) = \
|
|
unpack('<ii', dent[116:124])
|
|
if cbufsize == 0:
|
|
self.name = UNICODE_LITERAL('')
|
|
else:
|
|
self.name = unicode(dent[0:cbufsize-2], 'utf_16_le') # omit the trailing U+0000
|
|
self.children = [] # filled in later
|
|
self.parent = -1 # indicates orphan; fixed up later
|
|
self.tsinfo = unpack('<IIII', dent[100:116])
|
|
if DEBUG:
|
|
self.dump(DEBUG)
|
|
|
|
def dump(self, DEBUG=1):
|
|
fprintf(
|
|
self.logfile,
|
|
"DID=%d name=%r etype=%d DIDs(left=%d right=%d root=%d parent=%d kids=%r) first_SID=%d tot_size=%d\n",
|
|
self.DID, self.name, self.etype, self.left_DID,
|
|
self.right_DID, self.root_DID, self.parent, self.children, self.first_SID, self.tot_size
|
|
)
|
|
if DEBUG == 2:
|
|
# cre_lo, cre_hi, mod_lo, mod_hi = tsinfo
|
|
print("timestamp info", self.tsinfo, file=self.logfile)
|
|
|
|
def _build_family_tree(dirlist, parent_DID, child_DID):
|
|
if child_DID < 0: return
|
|
_build_family_tree(dirlist, parent_DID, dirlist[child_DID].left_DID)
|
|
dirlist[parent_DID].children.append(child_DID)
|
|
dirlist[child_DID].parent = parent_DID
|
|
_build_family_tree(dirlist, parent_DID, dirlist[child_DID].right_DID)
|
|
if dirlist[child_DID].etype == 1: # storage
|
|
_build_family_tree(dirlist, child_DID, dirlist[child_DID].root_DID)
|
|
|
|
|
|
class CompDoc(object):
|
|
"""
|
|
Compound document handler.
|
|
|
|
:param mem:
|
|
The raw contents of the file, as a string, or as an :class:`mmap.mmap`
|
|
object. The only operation it needs to support is slicing.
|
|
"""
|
|
|
|
|
|
def __init__(self, mem, logfile=sys.stdout, DEBUG=0):
|
|
self.logfile = logfile
|
|
self.DEBUG = DEBUG
|
|
if mem[0:8] != SIGNATURE:
|
|
raise CompDocError('Not an OLE2 compound document')
|
|
if mem[28:30] != b'\xFE\xFF':
|
|
raise CompDocError('Expected "little-endian" marker, found %r' % mem[28:30])
|
|
revision, version = unpack('<HH', mem[24:28])
|
|
if DEBUG:
|
|
print("\nCompDoc format: version=0x%04x revision=0x%04x" % (version, revision), file=logfile)
|
|
self.mem = mem
|
|
ssz, sssz = unpack('<HH', mem[30:34])
|
|
if ssz > 20: # allows for 2**20 bytes i.e. 1MB
|
|
print("WARNING: sector size (2**%d) is preposterous; assuming 512 and continuing ..."
|
|
% ssz, file=logfile)
|
|
ssz = 9
|
|
if sssz > ssz:
|
|
print("WARNING: short stream sector size (2**%d) is preposterous; assuming 64 and continuing ..."
|
|
% sssz, file=logfile)
|
|
sssz = 6
|
|
self.sec_size = sec_size = 1 << ssz
|
|
self.short_sec_size = 1 << sssz
|
|
if self.sec_size != 512 or self.short_sec_size != 64:
|
|
print("@@@@ sec_size=%d short_sec_size=%d" % (self.sec_size, self.short_sec_size), file=logfile)
|
|
(
|
|
SAT_tot_secs, self.dir_first_sec_sid, _unused, self.min_size_std_stream,
|
|
SSAT_first_sec_sid, SSAT_tot_secs,
|
|
MSATX_first_sec_sid, MSATX_tot_secs,
|
|
) = unpack('<iiiiiiii', mem[44:76])
|
|
mem_data_len = len(mem) - 512
|
|
mem_data_secs, left_over = divmod(mem_data_len, sec_size)
|
|
if left_over:
|
|
#### raise CompDocError("Not a whole number of sectors")
|
|
mem_data_secs += 1
|
|
print("WARNING *** file size (%d) not 512 + multiple of sector size (%d)"
|
|
% (len(mem), sec_size), file=logfile)
|
|
self.mem_data_secs = mem_data_secs # use for checking later
|
|
self.mem_data_len = mem_data_len
|
|
seen = self.seen = array.array('B', [0]) * mem_data_secs
|
|
|
|
if DEBUG:
|
|
print('sec sizes', ssz, sssz, sec_size, self.short_sec_size, file=logfile)
|
|
print("mem data: %d bytes == %d sectors" % (mem_data_len, mem_data_secs), file=logfile)
|
|
print("SAT_tot_secs=%d, dir_first_sec_sid=%d, min_size_std_stream=%d"
|
|
% (SAT_tot_secs, self.dir_first_sec_sid, self.min_size_std_stream,), file=logfile)
|
|
print("SSAT_first_sec_sid=%d, SSAT_tot_secs=%d" % (SSAT_first_sec_sid, SSAT_tot_secs,), file=logfile)
|
|
print("MSATX_first_sec_sid=%d, MSATX_tot_secs=%d" % (MSATX_first_sec_sid, MSATX_tot_secs,), file=logfile)
|
|
nent = sec_size // 4 # number of SID entries in a sector
|
|
fmt = "<%di" % nent
|
|
trunc_warned = 0
|
|
#
|
|
# === build the MSAT ===
|
|
#
|
|
MSAT = list(unpack('<109i', mem[76:512]))
|
|
SAT_sectors_reqd = (mem_data_secs + nent - 1) // nent
|
|
expected_MSATX_sectors = max(0, (SAT_sectors_reqd - 109 + nent - 2) // (nent - 1))
|
|
actual_MSATX_sectors = 0
|
|
if MSATX_tot_secs == 0 and MSATX_first_sec_sid in (EOCSID, FREESID, 0):
|
|
# Strictly, if there is no MSAT extension, then MSATX_first_sec_sid
|
|
# should be set to EOCSID ... FREESID and 0 have been met in the wild.
|
|
pass # Presuming no extension
|
|
else:
|
|
sid = MSATX_first_sec_sid
|
|
while sid not in (EOCSID, FREESID, MSATSID):
|
|
# Above should be only EOCSID according to MS & OOo docs
|
|
# but Excel doesn't complain about FREESID. Zero is a valid
|
|
# sector number, not a sentinel.
|
|
if DEBUG > 1:
|
|
print('MSATX: sid=%d (0x%08X)' % (sid, sid), file=logfile)
|
|
if sid >= mem_data_secs:
|
|
msg = "MSAT extension: accessing sector %d but only %d in file" % (sid, mem_data_secs)
|
|
if DEBUG > 1:
|
|
print(msg, file=logfile)
|
|
break
|
|
raise CompDocError(msg)
|
|
elif sid < 0:
|
|
raise CompDocError("MSAT extension: invalid sector id: %d" % sid)
|
|
if seen[sid]:
|
|
raise CompDocError("MSAT corruption: seen[%d] == %d" % (sid, seen[sid]))
|
|
seen[sid] = 1
|
|
actual_MSATX_sectors += 1
|
|
if DEBUG and actual_MSATX_sectors > expected_MSATX_sectors:
|
|
print("[1]===>>>", mem_data_secs, nent, SAT_sectors_reqd, expected_MSATX_sectors, actual_MSATX_sectors, file=logfile)
|
|
offset = 512 + sec_size * sid
|
|
MSAT.extend(unpack(fmt, mem[offset:offset+sec_size]))
|
|
sid = MSAT.pop() # last sector id is sid of next sector in the chain
|
|
|
|
if DEBUG and actual_MSATX_sectors != expected_MSATX_sectors:
|
|
print("[2]===>>>", mem_data_secs, nent, SAT_sectors_reqd, expected_MSATX_sectors, actual_MSATX_sectors, file=logfile)
|
|
if DEBUG:
|
|
print("MSAT: len =", len(MSAT), file=logfile)
|
|
dump_list(MSAT, 10, logfile)
|
|
#
|
|
# === build the SAT ===
|
|
#
|
|
self.SAT = []
|
|
actual_SAT_sectors = 0
|
|
dump_again = 0
|
|
for msidx in xrange(len(MSAT)):
|
|
msid = MSAT[msidx]
|
|
if msid in (FREESID, EOCSID):
|
|
# Specification: the MSAT array may be padded with trailing FREESID entries.
|
|
# Toleration: a FREESID or EOCSID entry anywhere in the MSAT array will be ignored.
|
|
continue
|
|
if msid >= mem_data_secs:
|
|
if not trunc_warned:
|
|
print("WARNING *** File is truncated, or OLE2 MSAT is corrupt!!", file=logfile)
|
|
print("INFO: Trying to access sector %d but only %d available"
|
|
% (msid, mem_data_secs), file=logfile)
|
|
trunc_warned = 1
|
|
MSAT[msidx] = EVILSID
|
|
dump_again = 1
|
|
continue
|
|
elif msid < -2:
|
|
raise CompDocError("MSAT: invalid sector id: %d" % msid)
|
|
if seen[msid]:
|
|
raise CompDocError("MSAT extension corruption: seen[%d] == %d" % (msid, seen[msid]))
|
|
seen[msid] = 2
|
|
actual_SAT_sectors += 1
|
|
if DEBUG and actual_SAT_sectors > SAT_sectors_reqd:
|
|
print("[3]===>>>", mem_data_secs, nent, SAT_sectors_reqd, expected_MSATX_sectors, actual_MSATX_sectors, actual_SAT_sectors, msid, file=logfile)
|
|
offset = 512 + sec_size * msid
|
|
self.SAT.extend(unpack(fmt, mem[offset:offset+sec_size]))
|
|
|
|
if DEBUG:
|
|
print("SAT: len =", len(self.SAT), file=logfile)
|
|
dump_list(self.SAT, 10, logfile)
|
|
# print >> logfile, "SAT ",
|
|
# for i, s in enumerate(self.SAT):
|
|
# print >> logfile, "entry: %4d offset: %6d, next entry: %4d" % (i, 512 + sec_size * i, s)
|
|
# print >> logfile, "%d:%d " % (i, s),
|
|
print(file=logfile)
|
|
if DEBUG and dump_again:
|
|
print("MSAT: len =", len(MSAT), file=logfile)
|
|
dump_list(MSAT, 10, logfile)
|
|
for satx in xrange(mem_data_secs, len(self.SAT)):
|
|
self.SAT[satx] = EVILSID
|
|
print("SAT: len =", len(self.SAT), file=logfile)
|
|
dump_list(self.SAT, 10, logfile)
|
|
#
|
|
# === build the directory ===
|
|
#
|
|
dbytes = self._get_stream(
|
|
self.mem, 512, self.SAT, self.sec_size, self.dir_first_sec_sid,
|
|
name="directory", seen_id=3)
|
|
dirlist = []
|
|
did = -1
|
|
for pos in xrange(0, len(dbytes), 128):
|
|
did += 1
|
|
dirlist.append(DirNode(did, dbytes[pos:pos+128], 0, logfile))
|
|
self.dirlist = dirlist
|
|
_build_family_tree(dirlist, 0, dirlist[0].root_DID) # and stand well back ...
|
|
if DEBUG:
|
|
for d in dirlist:
|
|
d.dump(DEBUG)
|
|
#
|
|
# === get the SSCS ===
|
|
#
|
|
sscs_dir = self.dirlist[0]
|
|
assert sscs_dir.etype == 5 # root entry
|
|
if sscs_dir.first_SID < 0 or sscs_dir.tot_size == 0:
|
|
# Problem reported by Frank Hoffsuemmer: some software was
|
|
# writing -1 instead of -2 (EOCSID) for the first_SID
|
|
# when the SCCS was empty. Not having EOCSID caused assertion
|
|
# failure in _get_stream.
|
|
# Solution: avoid calling _get_stream in any case when the
|
|
# SCSS appears to be empty.
|
|
self.SSCS = ""
|
|
else:
|
|
self.SSCS = self._get_stream(
|
|
self.mem, 512, self.SAT, sec_size, sscs_dir.first_SID,
|
|
sscs_dir.tot_size, name="SSCS", seen_id=4)
|
|
# if DEBUG: print >> logfile, "SSCS", repr(self.SSCS)
|
|
#
|
|
# === build the SSAT ===
|
|
#
|
|
self.SSAT = []
|
|
if SSAT_tot_secs > 0 and sscs_dir.tot_size == 0:
|
|
print("WARNING *** OLE2 inconsistency: SSCS size is 0 but SSAT size is non-zero", file=logfile)
|
|
if sscs_dir.tot_size > 0:
|
|
sid = SSAT_first_sec_sid
|
|
nsecs = SSAT_tot_secs
|
|
while sid >= 0 and nsecs > 0:
|
|
if seen[sid]:
|
|
raise CompDocError("SSAT corruption: seen[%d] == %d" % (sid, seen[sid]))
|
|
seen[sid] = 5
|
|
nsecs -= 1
|
|
start_pos = 512 + sid * sec_size
|
|
news = list(unpack(fmt, mem[start_pos:start_pos+sec_size]))
|
|
self.SSAT.extend(news)
|
|
sid = self.SAT[sid]
|
|
if DEBUG: print("SSAT last sid %d; remaining sectors %d" % (sid, nsecs), file=logfile)
|
|
assert nsecs == 0 and sid == EOCSID
|
|
if DEBUG:
|
|
print("SSAT", file=logfile)
|
|
dump_list(self.SSAT, 10, logfile)
|
|
if DEBUG:
|
|
print("seen", file=logfile)
|
|
dump_list(seen, 20, logfile)
|
|
|
|
def _get_stream(self, mem, base, sat, sec_size, start_sid, size=None, name='', seen_id=None):
|
|
# print >> self.logfile, "_get_stream", base, sec_size, start_sid, size
|
|
sectors = []
|
|
s = start_sid
|
|
if size is None:
|
|
# nothing to check against
|
|
while s >= 0:
|
|
if seen_id is not None:
|
|
if self.seen[s]:
|
|
raise CompDocError("%s corruption: seen[%d] == %d" % (name, s, self.seen[s]))
|
|
self.seen[s] = seen_id
|
|
start_pos = base + s * sec_size
|
|
sectors.append(mem[start_pos:start_pos+sec_size])
|
|
try:
|
|
s = sat[s]
|
|
except IndexError:
|
|
raise CompDocError(
|
|
"OLE2 stream %r: sector allocation table invalid entry (%d)" %
|
|
(name, s)
|
|
)
|
|
assert s == EOCSID
|
|
else:
|
|
todo = size
|
|
while s >= 0:
|
|
if seen_id is not None:
|
|
if self.seen[s]:
|
|
raise CompDocError("%s corruption: seen[%d] == %d" % (name, s, self.seen[s]))
|
|
self.seen[s] = seen_id
|
|
start_pos = base + s * sec_size
|
|
grab = sec_size
|
|
if grab > todo:
|
|
grab = todo
|
|
todo -= grab
|
|
sectors.append(mem[start_pos:start_pos+grab])
|
|
try:
|
|
s = sat[s]
|
|
except IndexError:
|
|
raise CompDocError(
|
|
"OLE2 stream %r: sector allocation table invalid entry (%d)" %
|
|
(name, s)
|
|
)
|
|
assert s == EOCSID
|
|
if todo != 0:
|
|
fprintf(self.logfile,
|
|
"WARNING *** OLE2 stream %r: expected size %d, actual size %d\n",
|
|
name, size, size - todo)
|
|
|
|
return b''.join(sectors)
|
|
|
|
def _dir_search(self, path, storage_DID=0):
|
|
# Return matching DirNode instance, or None
|
|
head = path[0]
|
|
tail = path[1:]
|
|
dl = self.dirlist
|
|
for child in dl[storage_DID].children:
|
|
if dl[child].name.lower() == head.lower():
|
|
et = dl[child].etype
|
|
if et == 2:
|
|
return dl[child]
|
|
if et == 1:
|
|
if not tail:
|
|
raise CompDocError("Requested component is a 'storage'")
|
|
return self._dir_search(tail, child)
|
|
dl[child].dump(1)
|
|
raise CompDocError("Requested stream is not a 'user stream'")
|
|
return None
|
|
|
|
|
|
def get_named_stream(self, qname):
|
|
"""
|
|
Interrogate the compound document's directory; return the stream as a
|
|
string if found, otherwise return ``None``.
|
|
|
|
:param qname:
|
|
Name of the desired stream e.g. ``'Workbook'``.
|
|
Should be in Unicode or convertible thereto.
|
|
"""
|
|
d = self._dir_search(qname.split("/"))
|
|
if d is None:
|
|
return None
|
|
if d.tot_size >= self.min_size_std_stream:
|
|
return self._get_stream(
|
|
self.mem, 512, self.SAT, self.sec_size, d.first_SID,
|
|
d.tot_size, name=qname, seen_id=d.DID+6)
|
|
else:
|
|
return self._get_stream(
|
|
self.SSCS, 0, self.SSAT, self.short_sec_size, d.first_SID,
|
|
d.tot_size, name=qname + " (from SSCS)", seen_id=None)
|
|
|
|
def locate_named_stream(self, qname):
|
|
"""
|
|
Interrogate the compound document's directory.
|
|
|
|
If the named stream is not found, ``(None, 0, 0)`` will be returned.
|
|
|
|
If the named stream is found and is contiguous within the original
|
|
byte sequence (``mem``) used when the document was opened,
|
|
then ``(mem, offset_to_start_of_stream, length_of_stream)`` is returned.
|
|
|
|
Otherwise a new string is built from the fragments and
|
|
``(new_string, 0, length_of_stream)`` is returned.
|
|
|
|
:param qname:
|
|
Name of the desired stream e.g. ``'Workbook'``.
|
|
Should be in Unicode or convertible thereto.
|
|
"""
|
|
d = self._dir_search(qname.split("/"))
|
|
if d is None:
|
|
return (None, 0, 0)
|
|
if d.tot_size > self.mem_data_len:
|
|
raise CompDocError("%r stream length (%d bytes) > file data size (%d bytes)"
|
|
% (qname, d.tot_size, self.mem_data_len))
|
|
if d.tot_size >= self.min_size_std_stream:
|
|
result = self._locate_stream(
|
|
self.mem, 512, self.SAT, self.sec_size, d.first_SID,
|
|
d.tot_size, qname, d.DID+6)
|
|
if self.DEBUG:
|
|
print("\nseen", file=self.logfile)
|
|
dump_list(self.seen, 20, self.logfile)
|
|
return result
|
|
else:
|
|
return (
|
|
self._get_stream(
|
|
self.SSCS, 0, self.SSAT, self.short_sec_size, d.first_SID,
|
|
d.tot_size, qname + " (from SSCS)", None),
|
|
0,
|
|
d.tot_size,
|
|
)
|
|
|
|
def _locate_stream(self, mem, base, sat, sec_size, start_sid, expected_stream_size, qname, seen_id):
|
|
# print >> self.logfile, "_locate_stream", base, sec_size, start_sid, expected_stream_size
|
|
s = start_sid
|
|
if s < 0:
|
|
raise CompDocError("_locate_stream: start_sid (%d) is -ve" % start_sid)
|
|
p = -99 # dummy previous SID
|
|
start_pos = -9999
|
|
end_pos = -8888
|
|
slices = []
|
|
tot_found = 0
|
|
found_limit = (expected_stream_size + sec_size - 1) // sec_size
|
|
while s >= 0:
|
|
if self.seen[s]:
|
|
print("_locate_stream(%s): seen" % qname, file=self.logfile); dump_list(self.seen, 20, self.logfile)
|
|
raise CompDocError("%s corruption: seen[%d] == %d" % (qname, s, self.seen[s]))
|
|
self.seen[s] = seen_id
|
|
tot_found += 1
|
|
if tot_found > found_limit:
|
|
# Note: expected size rounded up to higher sector
|
|
raise CompDocError(
|
|
"%s: size exceeds expected %d bytes; corrupt?"
|
|
% (qname, found_limit * sec_size)
|
|
)
|
|
if s == p+1:
|
|
# contiguous sectors
|
|
end_pos += sec_size
|
|
else:
|
|
# start new slice
|
|
if p >= 0:
|
|
# not first time
|
|
slices.append((start_pos, end_pos))
|
|
start_pos = base + s * sec_size
|
|
end_pos = start_pos + sec_size
|
|
p = s
|
|
s = sat[s]
|
|
assert s == EOCSID
|
|
assert tot_found == found_limit
|
|
# print >> self.logfile, "_locate_stream(%s): seen" % qname; dump_list(self.seen, 20, self.logfile)
|
|
if not slices:
|
|
# The stream is contiguous ... just what we like!
|
|
return (mem, start_pos, expected_stream_size)
|
|
slices.append((start_pos, end_pos))
|
|
# print >> self.logfile, "+++>>> %d fragments" % len(slices)
|
|
return (b''.join(mem[start_pos:end_pos] for start_pos, end_pos in slices), 0, expected_stream_size)
|
|
|
|
# ==========================================================================================
|
|
def x_dump_line(alist, stride, f, dpos, equal=0):
|
|
print("%5d%s" % (dpos, " ="[equal]), end=' ', file=f)
|
|
for value in alist[dpos:dpos + stride]:
|
|
print(str(value), end=' ', file=f)
|
|
print(file=f)
|
|
|
|
def dump_list(alist, stride, f=sys.stdout):
|
|
def _dump_line(dpos, equal=0):
|
|
print("%5d%s" % (dpos, " ="[equal]), end=' ', file=f)
|
|
for value in alist[dpos:dpos + stride]:
|
|
print(str(value), end=' ', file=f)
|
|
print(file=f)
|
|
pos = None
|
|
oldpos = None
|
|
for pos in xrange(0, len(alist), stride):
|
|
if oldpos is None:
|
|
_dump_line(pos)
|
|
oldpos = pos
|
|
elif alist[pos:pos+stride] != alist[oldpos:oldpos+stride]:
|
|
if pos - oldpos > stride:
|
|
_dump_line(pos - stride, equal=1)
|
|
_dump_line(pos)
|
|
oldpos = pos
|
|
if oldpos is not None and pos is not None and pos != oldpos:
|
|
_dump_line(pos, equal=1)
|
|
|