undz.py

#!/usr/bin/env python3

"""
Copyright (C) 2016 Elliott Mitchell <ehem+android@m5p.com>
Copyright (C) 2013 IOMonster (thecubed on XDA)

        This program is free software: you can redistribute it and/or modify
        it under the terms of the GNU General Public License as published by
        the Free Software Foundation, either version 3 of the License, or
        (at your option) any later version.

        This program is distributed in the hope that it will be useful,
        but WITHOUT ANY WARRANTY; without even the implied warranty of
        MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
        GNU General Public License for more details.

        You should have received a copy of the GNU General Public License
        along with this program.  If not, see <http://www.gnu.org/licenses/>.
"""

from __future__ import print_function
import os
import sys
import io
import zlib
import zstd
import argparse
import hashlib
from binascii import crc32, b2a_hex
from uuid import UUID

# our tools are in "libexec"
sys.path.append(os.path.join(sys.path[0], "libexec"))

import dz
import gpt


class UNDZUtils(object):
        """
        Common class for unpacking DZ file structures
        """


        def loadHeader(self, file):
                """
                Loads a structured header, does common processing and returns
                dictionary with data (buffer stored as "buffer")
                """

                # Read the header structure
                buffer = file.read(self._dz_length)


                # "Make the item"
                # Create a new dict using the keys from the format string
                # and the format string itself
                # and apply the format to the buffer
                dz_item = self.unpackdict(buffer)


                # Verify DZ area header
                if dz_item == None:
                        print("[!] Bad DZ {:s} header!".format(self._dz_area), file=sys.stderr)
                        sys.exit(1)


                # some paths want to take a look at the raw data
                dz_item['buffer'] = buffer


                # Collapse (truncate) each key's value if it's listed as collapsible
                for key in self._dz_collapsibles:
                        if type(dz_item[key]) is str or type(dz_item[key]) is bytes:
                                dz_item[key] = dz_item[key].rstrip(b'\x00')
                                if b'\x00' in dz_item[key]:
                                        print("[!] Warning: extraneous data found IN "+key, file=sys.stderr)
                                        #sys.exit(1)
                        elif type(dz_item[key]) is int:
                                if dz_item[key] != 0:
                                        print('[!] Error: Value supposed to be zero in field "'+key+'" is non-zero ('+hex(dz_item[key])+')', file=sys.stderr)
                                        sys.exit(1)
                        else:
                                print("[!] Error: internal error", file=sys.stderr)
                                sys.exit(-1)

                # To my knowledge this is supposed to be blank (for now...)
                if len(dz_item['pad']) != 0:
                        print("[!] Warning: pad is not empty", file=sys.stderr)

                return dz_item



class UNDZChunk(dz.DZChunk, UNDZUtils):
        """
        Representation of an individual file chunk from a LGE DZ file
        """


        def getChunkName(self):
                """
                Return the name of our chunk
                """
                name = self.chunkName.decode("utf8")
                if self.dev > 0:
                        name = chr(ord('A') + self.dev) + "." + name
                return name

        def getSliceName(self):
                """
                Return the name of the slice we're located in
                """
                return self.sliceName.decode("utf8")

        def getLength(self):
                """
                Return the length of our chunk (amount of compressed data)
                """
                return self.dataSize

        def getMessages(self):
                """
                Return any messages generated while loading us
                """
                return self.messages

        def getDataOffset(self):
                """
                Return the offset where our payload should be located
                """
                return self.dataOffset

        def getDev(self):
                """
                Return which pass we're supposed to be written in
                """
                return self.dev

        def getTargetStart(self):
                """
                Return the offset into the target storage medium where we start
                """
                return self.targetAddr << self.dz.shiftLBA

        def getTargetEnd(self):
                """
                Return the offset into the target storage medium where we end
                """
                return (self.targetAddr << self.dz.shiftLBA) + self.targetSize

        def getNext(self):
                """
                Return offset of next chunk
                """
                return self.dataOffset + self.dataSize

        def Messages(self, file=sys.stdout):
                """
                Write our messages to file
                """
                # Print our messages
                for m in self.messages:
                        print(m, file=file)


        def display(self, sliceIdx, selfIdx):
                """
                Display information about our chunk
                """
                
                if cmd.batchMode:
                    print("{:d}:{:s}:data".format(sliceIdx,self.sliceName.decode("utf8")))
                else:
                    print("{:2d}/{:2d} : {:s} ({:d} bytes)".format(sliceIdx, selfIdx, self.chunkName.decode("utf8"), self.dataSize))
                self.Messages()
                return ++selfIdx

        def extract(self):
                """
                Extracts our payload from the compressed DZ file using ZLIB.
                self function could be particularly memory-intensive when used
                with large chunks, as the entire compressed chunk is loaded
                into RAM and decompressed.

                A better way to do self would be to chunk the zlib compressed
                data and decompress it with zlib.decompressor() and a while
                loop.

                I'm lazy though, and y'all have fast computers, so self is good
                enough.

                Starting with G7 KDZs, LG switched to zstandard compression.
                To keep comparibility with older KDZs, we are going to compare
                the compression header to the standard zlib header. If there, we 
                use zlib .. if not, we use zstandard.
                """

                # Seek to the beginning of the compressed data in the specified partition
                self.dz.dzfile.seek(self.dataOffset, io.SEEK_SET)

                zlib_magic = {'zlib': bytes([0x78, 0x01])}
                cmp_header = self.dz.dzfile.read(2)

                # Reset to the beginning of the compressed data
                self.dz.dzfile.seek(self.dataOffset, io.SEEK_SET)

                # Read the whole compressed segment into RAM
                zdata = self.dz.dzfile.read(self.dataSize)

                if cmp_header.startswith(zlib_magic['zlib']):

                    # Decompress the data with zlib
                    buf = zlib.decompress(zdata)

                else:
                    # decompress with zstandard
                    buf = zstd.ZSTD_uncompress(zdata)
    
                crc = crc32(buf) & 0xFFFFFFFF

                #if crc != self.crc32:
        ##              print("[!] Error: CRC32 of data doesn't match header ({:08X} vs {:08X})".format(crc, self.crc32), file=sys.stderr)
        #               sys.exit(1)

                md5 = hashlib.md5()
                md5.update(buf)

                if md5.digest() != self.md5:
                        print("[!] Error: MD5 of data doesn't match header ({:32s} vs {:32s})".format(md5.hexdigest(), b2a_hex(self.md5)), file=sys.stderr)
                        sys.exit(1)

                return buf

        def extractChunk(self, file, name):
                """
                Extract the payload of our chunk into the file with the name

                Extracts our payload from the compressed DZ file using ZLIB.
                self function could be particularly memory-intensive when used
                with large chunks, as the entire compressed chunk is loaded
                into RAM and decompressed.

                A better way to do self would be to chunk the zlib compressed
                data and decompress it with zlib.decompressor() and a while
                loop.

                I'm lazy though, and y'all have fast computers, so self is good
                enough.
                """

                if name:
                        print("[+] Extracting {:s} to {:s}".format(self.chunkName.decode("utf8"), name))

                # Create a hole at the end of the wipe area
                if file:
                        current = file.seek(0, io.SEEK_CUR)

#                       # Ensure space is allocated to areas to be written
#                       for addr in range(self.trimCount):
#                               file.seek(1<<self.dz.shiftLBA, io.SEEK_CUR)
#                               file.write(b'\x00')
#                       file.seek(current, io.SEEK_SET)
                        # Makes the output the correct size, by filling as hole
                        file.truncate(current + (self.trimCount<<self.dz.shiftLBA))

                # Write it to file
                file.write(self.extract())

                # Print our messages
                self.Messages()

        def extractChunkfile(self, file, name):
                """
                Extract the raw data of our chunk into the file with the name
                """

                print("[+] Extracting {:s} to {:s}".format(self.chunkName.decode("utf8"), name))

                self.dz.dzfile.seek(self.dataOffset-self._dz_length, io.SEEK_SET)
                buffer = self.dz.dzfile.read(self.dataSize + self._dz_length)
                file.write(buffer)

                # Print our messages
                self.Messages()

        def __init__(self, dz, file):
                """
                Loads the DZ header in the form as defined by self._dz_chunk_dict
                """

                super(UNDZChunk, self).__init__()

                # Save a pointer to the UNDZFile
                self.dz = dz

                # Load the header, does common checking
                dz_item = self.loadHeader(file)

                # used for warnings about the chunk
                self.messages = []

                # Record the "offset" where our chunk was declared,
                # allows us to resolve where in the compressed data is
                self.dataOffset = file.tell()

                # Add ourselves to the hashes for checking
                dz.md5Headers.update(dz_item['buffer'])

### experiment, results negative
#               dz.sha1Headers.update(dz_item['buffer'])
#
#               dz.crcHeaders = crc32(dz_item['buffer'], dz.crcHeaders)
#
#               dz.md5HeaderNZ.update(dz_item['buffer'][0:-len(dz_item['pad'])])
#               dz.crcHeaderNZ=crc32(dz_item['buffer'][0:-len(dz_item['pad'])], dz.crcHeaders)
### experiment, results negative


                #
                if dz_item['targetSize']&0x1FF != 0:
                        self.messages.append("[?] Warning: uncompressed size is {:d}, not a multiple of 512 (please report!)".format(dz_item['targetSize']))

                # Save off all the important data
                self.sliceName  = dz_item['sliceName']
                self.chunkName  = dz_item['chunkName']
                self.targetAddr = dz_item['targetAddr']
                self.targetSize = dz_item['targetSize']
                self.dataSize   = dz_item['dataSize']
                self.md5        = dz_item['md5']
                self.trimCount  = dz_item['trimCount']
                self.crc32      = dz_item['crc32']
                self.dev        = dz_item['dev']

                # The use of these non-.bin chunks is unknown
                if self.chunkName[-4:] == b".img":
                        return

                # This is where in the image we're supposed to go
                # This sanity check is broken for now. I am working on a better solution
                # Not even sure if it is needed, since you would have a decompress failure
#                targetAddr = int(self.chunkName[len(self.sliceName)+1:-4])

#                if targetAddr != self.targetAddr:
#                        self.messages.append("[!] Uncompressed starting offset differs from chunk name!")
                targetAddr = self.targetAddr


class UNDZSlice(object):
        """
        Representation of a diskslice from a LGE DZ file
        """

        def addChunk(self, chunk):
                """
                Add a chunk to our diskslice
                """

                offset = chunk.getTargetStart()
                # if it is at the start...
                if offset < self.start:
                        print("[!] Warning: Chunk is part of \"{:s}\", but starts in front of slice?!".format(self.name), file=sys.stderr)

                self.chunks.append(chunk)


        def getStart(self):
                """
                Get the starting offset of our slice
                """
                return self.start

        def getEnd(self):
                """
                Get the ending offset of our slice
                """
                return self.end

        def getLength(self):
                """
                Get the length of our slice
                """
                return self.end-self.start

        def getIndex(self):
                """
                Get our index from GPT
                """
                return self.index

        def display(self, sliceIdx, chunkIdx):
                """
                Display information on the various chunks in our slice
                Return the last index we used
                """
                if len(self.chunks) == 0:
                        if not self.index:
                                chunkIdx = None
                                sliceIdx = -1
                        if cmd.batchMode:
                            print("{:2d}:{:s}:empty".format(sliceIdx,self.name))
                            # elif sliceIdx != -1:
                        else:
                            print("{:2d}/?? : {:s} (<empty>)".format(sliceIdx, self.name))
                for chunk in self.chunks:
                        chunk.display(sliceIdx,chunkIdx)
                        chunkIdx+=1
                return chunkIdx

        def getChunkCount(self):
                """
                Get the number of chunks in our slice
                """
                return len(self.chunks)

        def getSliceName(self):
                """
                Get the name of our slice
                """
                return self.name

        def extractChunk(self, file, name, idx):
                """
                Extract a given chunk
                """
                self.chunks[idx].extractChunk(file, name)

        def extractChunkfile(self, file, name, idx):
                """
                Extract a given chunk
                """
                self.chunks[idx].extractChunkfile(file, name)

        def extractSlice(self, file, name):
                """
                Extract the whole slice to the FileIO file named name
                """

                start = self.getStart()
                end = self.getEnd()

                for chunk in self.chunks:
                        cur = chunk.getTargetStart()
                        # Mostly happens for the backup GPT (large pad at start)
                        if cur < start:
                                # this ensures messages from extraction show up
                                chunk.extractChunk(file, name)
                                file.seek(0, io.SEEK_SET)
                                file.truncate(0)
                                # in case the long buffer was reeeally looong

                                buf = chunk.extract()
                                file.write(buf[cur-start:])
                        else:
                                file.seek(cur-start, io.SEEK_SET)
                                chunk.extractChunk(file, name)

                # it is possible for chunks wipe area to extend beyond slice
                if self.getLength() >= 0:
                        file.truncate(self.getLength())


                # write a params file for saving values used during recreate
                params = io.open(name + ".params", "wt")
                params.write(u'# saved parameters for the file "{:s}"\n'.format(name))
                params.write(u"startLBA={:d}\n".format(start >> self.dz.shiftLBA))
                params.write(u"startAddr={:d}\n".format(start))
                params.write(u"endLBA={:d}\n".format(end >> self.dz.shiftLBA))
                params.write(u"endAddr={:d}\n".format(end))
                params.write(u"# this value may be crucial for success and dangerous to modify\n")

                if len(self.chunks) > 0:
                        last = self.chunks[-1]
                        params.write(u"lastWipe={:d}\n".format((last.getTargetStart() >> self.dz.shiftLBA) + last.trimCount))
                        params.write(u"# Indicates which flash device this should be written in\n")
                        params.write(u"dev={:d}\n".format(self.chunks[0].getDev()))
                        params.write(u"# the block size is important!\n")
                        params.write(u"blockSize={:d}\n".format(1<<self.dz.shiftLBA))
                        params.write(u"blockShift={:d}\n".format(self.dz.shiftLBA))
                else:
                        params.write(u"phantom=1\n")
                        params.write(u"# this is a phantom slice, no writes are done\n")
                        params.write(u"# (though it could be getting wiped)\n")

                params.close()

        def __init__(self, dz, index, name, start=0x7FFFFFFFFFFFFFFF, end=0):
                """
                Initialize the instance of UNDZSlice class
                """

                super(UNDZSlice, self).__init__()

                self.name = name
                self.chunks = []
                self.messages = set()
                self.start = start
                self.end = end

                # Save a pointer to the UNDZFile
                self.dz = dz
                self.index = index



class UNDZFile(dz.DZFile, UNDZUtils):
        """
        Representation of the data parsed from a LGE DZ file
        """


        def open(self, name):
                """
                What do you expect? Open file and check the header
                """

                # Open the file
                try:
                        self.dzfile = io.open(name, "rb")
                except IOError as err:
                        print(err, file=sys.stderr)
                        sys.exit(1)

                # Get length of whole file
                self.length = self.dzfile.seek(0, io.SEEK_END)
                self.dzfile.seek(0, io.SEEK_SET)


                # Load the header, does common checking
                dz_file = self.loadHeader(self.dzfile)

                # Save the full header for rebuilding the file later
                self.header = dz_file['buffer']

                #print(dz_file['version'])
                #print(dz_file['buildType'])
                #print(dz_file['oldDateCode'])
                #print(dz_file['chunkCount'])
                #print(dz_file['md5'])
                #print(dz_file['unknown0'])
                #print(dz_file['reserved1'])
                #print(dz_file['reserved4'])
                #print(dz_file['unknown1'])
                #print(dz_file['unknown2'])
                #print(self.header)

                # Appears to be version numbers for the format
                if dz_file['formatMajor'] > 2:
                        print("[!] Error: DZ format version too high! (please report)", file=sys.stderr)
                        sys.exit(1)
                elif dz_file['formatMinor'] > 1:
                        print("[!] Warning: DZ format more recent than previous versions, output unreliable", file=sys.stderr)


                self.chunkCount = dz_file['chunkCount']

                # save this for creating modified files later
                # (ro.lge.factoryversion)
                self.ro_lge_factoryversion = dz_file['version']

                self.formatMajor = dz_file['formatMajor']
                self.formatMinor = dz_file['formatMinor']

                # currently only "user" has been seen in wild
                self.buildType = dz_file['buildType']

                # save this for consistency checking
                self.md5 = dz_file['md5']

                # save these for later analysis
                self.unknown0 = dz_file['unknown0']
                self.unknown1 = dz_file['unknown1']
                self.unknown2 = dz_file['unknown2']
                self.unknown3 = dz_file['unknown3']

                # save for reportting and possibly reconstruction later
                self.old_date_code = dz_file['oldDateCode']
                self.device = dz_file['device']
                self.android_version = dz_file['androidVer']
                self.unknown4 = dz_file['unknown4']
                self.unknown5 = dz_file['unknown5']


        def loadChunks(self):
                """
                Loads the headers of the chunks to prepare for listing|extract
                """

                # are the chunks out of order in regards to image order?
                disorder = 0
                last = -1
                dev = -1

                while True:

                        # Read each segment's header
                        chunk = UNDZChunk(self, self.dzfile)
                        self.chunks.append(chunk)

                        # check ordering
                        if dev > chunk.getDev():
                                if chunk.getChunkName()[-4:] != ".img":
                                        disorder += 1
                                        dev = chunk.getDev()
                        elif dev < chunk.getDev():
                                last = -1
                                dev = chunk.getDev()

                        if last > chunk.getTargetStart():
                                disorder += 1
                        last = chunk.getTargetStart()

                        # Would seeking the file to the end of the compressed
                        # data bring us to the end of the file, or beyond it?
                        next = chunk.getNext()
                        if next >= int(self.length):
                                break

                        # Seek to next DZ header
                        self.dzfile.seek(next, io.SEEK_SET)

                # If I'm perverse enough to think of this...
                if disorder > 0:
                        print("[ ] Warning: Found {:d} out of order chunks (please report)".format(disorder), file=sys.stderr)

                # They're in the order to write, not block order though
                self.chunks.sort(key=lambda c: (c.getTargetStart() + (c.getDev()<<48)))

                try:
                        emptycount = 0
                        g = gpt.GPT(self.chunks[0].extract())
                        ordered = range(len(g.slices)) if g.ordered else range(len(g.slices)).sort(key=lambda s: g.slices[s].startLBA)

                        self.shiftLBA = g.shiftLBA

                        next = g.dataStartLBA
                        slice = UNDZSlice(self, 0, self.chunks[0].getSliceName(), 0, next<<self.shiftLBA)
                        self.slices.append(slice)
                        self.sliceIdx[self.chunks[0].getSliceName()] = slice

                        index = 0
                        while index < len(g.slices):
                                if g.slices[index].type == UUID(int=0):
                                        del g.slices[index]
                                else:
                                        index += 1

                        index = 1
                        for slice in g.slices:
                                new = UNDZSlice(self, index, slice.name, slice.startLBA<<self.shiftLBA, (slice.endLBA+1)<<self.shiftLBA)
                                self.slices.append(new)
                                self.sliceIdx[slice.name] = new
                                index += 1

                        for i in range(len(g.slices)):
                                if next != g.slices[i].startLBA:
                                        print("[!] Unallocated space found. Slice, Start, Size, End: " + str(next) + " " + str((g.slices[i].startLBA - next)<<self.shiftLBA), next<<self.shiftLBA, (g.slices[i].startLBA-1)<<self.shiftLBA)
                                        emptycount += 1
                                next = g.slices[i].endLBA+1

                        if next != g.dataEndLBA+1:
                                new = UNDZSlice(self, None, "_unallocated_" + str(emptycount), next<<self.shiftLBA, g.dataEndLBA<<self.shiftLBA)
                                self.slices.append(new)
                                emptycount += 1
                                next = g.dataEndLBA+1

                        slice = UNDZSlice(self, index, self.chunks[-1].getSliceName(), g.dataEndLBA<<self.shiftLBA, (g.altLBA+1)<<self.shiftLBA)
                        self.slices.append(slice)
                        self.sliceIdx[self.chunks[-1].getSliceName()] = slice

                except gpt.NoGPT as err:
                        print("[!] Unable to find GPT in DZ file: {:s}".format(err))
                        pass

                for chunk in self.chunks:
                        self.addChunk(chunk)

        def checkValues(self):
                """
                Check values for consistency with suspected use
                """

                # This does look like a count of chunks
                if len(self.chunks) != self.chunkCount:
                        print("[!] Error: chunks in header differs from chunks found (please report)", file=sys.stderr)
                        sys.exit(-1)

                # Checking this field for what is expected
                md5Headers = self.md5Headers.digest()

                if md5Headers != self.md5:
                        print("[!] Error: MD5 of chunk headers doesn't match header ({:32s} vs {:32s})".format(self.md5Headers.hexdigest(), b2a_hex(self.md5)), file=sys.stderr)
                        sys.exit(-1)


                # these are speculative, disabled for others
                return 0
                # Other speculation
                md5HeaderNZ = self.md5HeaderNZ.digest()

                if md5HeaderNZ == self.unknown2:
                        self.messages.add("[ ] unknown2 is consistent with MD5 of non-zero header areas")
                else:
                        self.messages.add("[ ] MD5 of non-zero header areas not found ({:32s})".format(self.md5HeaderNZ.hexdigest()))


                self.crcHeaders = self.crcHeaders & 0xFFFFFFFF
                if self.crcHeaders == self.unknown0:
                        self.messages.add("[ ] unknown0 is consistent with CRC32 of headers")
                elif self.crcHeaders == self.unknown1:
                        self.messages.add("[ ] unknown1 is consistent with CRC32 of headers")
                elif self.crcHeaders == self.unknown4:
                        self.messages.add("[ ] unknown4 is consistent with CRC32 of headers")
                else:
                        self.messages.add("[ ] No CRC32 of headers found ({:08X})".format(self.crcHeaders))


                self.crcHeaderNZ = self.crcHeaderNZ & 0xFFFFFFFF
                if self.crcHeaderNZ == self.unknown0:
                        self.messages.add("[ ] unknown0 is consistent with CRC32 of non-zero header areas")
                elif self.crcHeaderNZ == self.unknown1:
                        self.messages.add("[ ] unknown1 is consistent with CRC32 of non-zero header areas")
                elif self.crcHeaderNZ == self.unknown4:
                        self.messages.add("[ ] unknown4 is consistent with CRC32 of non-zero header areas")
                else:
                        self.messages.add("[ ] No CRC32 of non-zero header areas found ({:08X})".format(self.crcHeaders))


                if self.unknown0 == 256:
                        self.messages.add("[ ] unknown 0 is 256 like always (half blocksize?)")


        def addChunk(self, chunk):
                """
                Adds a chunk to some slice, potentially creating a new slice
                """

                name = chunk.getSliceName()

                # Get the needed slice
                if name in self.sliceIdx:
                        slice = self.sliceIdx[name]
                else:
# FIXME: what if chunks out of order?
                        slice = UNDZSlice(self, self.slices[-1].getIndex()+1, name)
                        self.slices.append(slice)
                        self.sliceIdx[name] = slice

                # Add it
                slice.addChunk(chunk)

        def display(self):
                """
                Display information on the various chunks that were found
                """
                chunkIdx = 0
                sliceIdx = 0
                for slice in self.slices:
                        count = slice.display(sliceIdx, chunkIdx)
                        if count != None:
                                chunkIdx = count
                                sliceIdx+=1

                for m in self.messages:
                        print(m)

        def getChunkCount(self):
                """
                Return the number of chunks in the whole file
                """
                return len(self.chunks)

        def getSliceCount(self):
                """
                Return the number of slices we've got
                """
                return len(self.slices)

        def getSlice(self, idx):
                """
                Return the slice with the given index
                """
                return self.slices[idx]

        def getChunk(self, idx):
                """
                Return the chunk with the given index
                """
                return self.chunks[idx]

        def getChunkName(self, idx):
                """
                Return the name of the given chunk index
                """
                return self.chunks[idx].getChunkName()

        def getSliceName(self, idx):
                """
                Return the name of the given slice index
                """
                return self.slices[idx].getSliceName()

        def extractChunk(self, file, name, idx, slice=None):
                """
                Extract a given chunk
                """
                if slice:
                        self.slices[slice].extractChunk(file, name, idx)
                else:
                        self.chunks[idx].extractChunk(file, name)

        def extractChunkfile(self, file, name, idx, slice=None):
                """
                Extract a given chunkfile
                """
                if slice:
                        self.slices[slice].extractChunkfile(file, name, idx)
                else:
                        self.chunks[idx].extractChunkfile(file, name)

        def extractSlice(self, file, name, idx):
                """
                Extract the whole slice to the FileIO file named name
                """
                return self.slices[idx].extractSlice(file, name)

        def extractImage(self, file, name):
                """
                Extract the whole file to an image file named name
                """

                # the slice extraction has gotten preoccupied with slices
                for chunk in self.chunks:
                        file.seek(chunk.getTargetStart(), io.SEEK_SET)
                        chunk.extractChunk(file, name)


        def saveHeader(self, name):
                """
                Dump the header from the original file into the output dir
                """
                params = open(".dz.params", "wt")
                params.write('# saved parameters from the file "{:s}"\n'.format(name))
                params.write("format_major={:d}\n".format(self.formatMajor))
                params.write("format_minor={:d}\n".format(self.formatMinor))
                params.write("device={:s}\n".format(self.device.decode("utf8")))
                params.write("# the property: ro.lge.factoryversion\n")
                params.write("factoryversion={:s}\n".format(self.ro_lge_factoryversion.decode("utf8")))
                params.write("# the block size is needed for some sanity checks\n")
                params.write("blockShift={:d}\nblockSize={:d}\n".format(self.shiftLBA, 1<<self.shiftLBA))
                params.write("# this is unknown, perhaps indicating block size?\n")
                params.write("unknown0={:d}\n".format(self.unknown0))
                params.write("# this is suspected to be a build type indicator of some flavor\n")
                params.write("build_type={:s}\n".format(self.buildType.decode("utf8")))
                params.write("# {:d} chunks were in original file\n".format(self.chunkCount))
                params.write("# guessing this is a date code, perhaps anti-rollback?\n")
                params.write("old_date_code={:s}\n".format(self.old_date_code.decode("utf8")))
                params.write("# Appears to indicate Android version, if present\n")
                params.write("android_version={:s}\n".format(self.android_version.decode("utf8")))
                params.write("# right size for an MD5 of /something/\n")
                params.write("unknown1={:s}\n".format(b2a_hex(self.unknown1).decode("utf8")))
                params.write("# some sort of values for /something/; absent from H901, present on ALL others\n")
                params.write("unknown2={:s}\n".format(self.unknown2.decode("utf8")))
                params.write("# date code?  CRC32 of thing with MD5?\n")
                params.write("unknown3={:s}\n".format(b2a_hex(self.unknown3).decode("utf8")))
                params.write("# flagging something?\n")
                params.write("unknown4={:d}\n".format(self.unknown4))
                params.write("# this almost looks like a bar-code of bytes?\n")
                params.write("unknown5={:d}\n".format(self.unknown5))

                params.close()


        def __init__(self, name):
                """
                Constructing this class opens the file and loads map of chunks
                """

                super(UNDZFile, self).__init__()

                self.slices = []
                self.sliceIdx = {}

                self.chunks = []

                self.messages = set()

                # Hash of the headers for consistency checking
                self.md5Headers = hashlib.new("md5")

                # A reasonable default
                # FIXME: need to do somehow do this better
                self.shiftLBA = 9

                # Hashes candidates for data in header area, all the chunk
                # headers, all the payload data, or everything
#               self.sha1Headers = hashlib.new("sha1")
#               self.crcHeaders = crc32(b"")
#               self.md5HeaderNZ = hashlib.md5()
#               self.crcHeaderNZ = crc32(b"")
#               self.md5Payload = hashlib.md5()
#               self.crcPayload = crc32(b"")
#               self.md5Image = hashlib.md5()
#               self.crcImage = crc32(b"")
#               self.md5All = hashlib.md5()
#               self.crcAll = crc32(b"")
#               # try crc32 ?

                self.open(name)
                self.loadChunks()
                self.checkValues()




class DZFileTools:
        """
        LGE Compressed DZ File tools
        """

        # Setup variables
        outdir = "dzextracted"

        def parseArgs(self):
                # Parse arguments
                parser = argparse.ArgumentParser(description='LG Compressed DZ File Extractor originally by IOMonster')
                parser.add_argument('-f', '--file', help='DZ File to read', action='store', required=True, dest='dzfile')
                parser.add_argument('-b', '--batch', help='batch mode', action='store_true', dest='batchMode')
                group = parser.add_mutually_exclusive_group(required=True)
                group.add_argument('-l', '--list', help='list slices/partitions', action='store_true', dest='listOnly')
                group.add_argument('-x', '--extract', help='extract chunk-file(s) for reconstruction (all by default)', action='store_true', dest='extractChunkfile')
                group.add_argument('-c', '--chunk', help='extract data chunk(s) (all by default)', action='store_true', dest='extractChunk')
                group.add_argument('-s', '--single', help='extract diskslice(s) (partition(s)) (all by default)', action='store_true', dest='extractSlice')
                group.add_argument('-i', '--image', help='extract all slices/partitions as a disk image', action='store_true', dest='extractImage')
                parser.add_argument('-d', '--dir', '-o', '--out', help='output location', action='store', dest='outdir')

                return parser.parse_known_args()

        def cmdListPartitions(self):
            if not cmd.batchMode:
                print("[+] DZ Partition List\n=========================================")
            self.dz_file.display()

        def cmdExtractChunk(self, files):
                if len(files) == 0:
                        print("[+] Extracting all chunks!\n")
                        files = range(0, self.dz_file.getChunkCount())
                elif len(files) == 1:
                        print("[+] Extracting single chunk!\n")
                else:
                        print("[+] Extracting {:d} chunks!\n".format(len(files)))

                for idx in files:
                        try:
                                idx = int(idx)
                        except ValueError:
                                print('[!] Bad value "{:s}" (must be number)'.format(idx), file=sys.stderr)
                                sys.exit(1)
                        if idx < 0 or idx >= self.dz_file.getChunkCount():
                                print("[!] Cannot extract out of range chunk {:d} (min=0 max={:d})".format(idx, self.dz_file.getChunkCount()-1), file=sys.stderr)
                                sys.exit(1)
                        name = self.dz_file.getChunkName(idx)
                        file = io.FileIO(name, "wb")
                        self.dz_file.extractChunk(file, name, idx)
                        file.close()

        def cmdExtractChunkfile(self, files):
                if len(files) == 0:
                        print("[+] Extracting all chunkfiles!\n")
                        files = range(0, self.dz_file.getChunkCount())
                elif len(files) == 1:
                        print("[+] Extracting single chunkfile!\n")
                else:
                        print("[+] Extracting {:d} chunkfiles!\n".format(len(files)))

                for idx in files:
                        try:
                                idx = int(idx)
                        except ValueError:
                                print('[!] Bad value "{:s}" (must be number)'.format(idx), file=sys.stderr)
                                sys.exit(1)
                        if idx < 0 or idx >= self.dz_file.getChunkCount():
                                print("[!] Cannot extract out of range chunkfile {:d} (min=0 max={:d})".format(idx, self.dz_file.getChunkCount()-1), file=sys.stderr)
                                sys.exit(1)
                        name = self.dz_file.getChunkName(idx) + ".chunk"
                        file = io.open(name, "wb")
                        self.dz_file.extractChunkfile(file, name, idx)
                        file.close()

        def cmdExtractSlice(self, files):
                if len(files) == 0:
                        print("[+] Extracting all slices/partitions\n")
                        files = range(0, self.dz_file.getSlice(-1).getIndex()+1)
                elif len(files) == 1:
                        print("[+] Extracting single slice / partition!\n")
                else:
                        print("[+] Extracting {:d} slices^Wpartitions!\n".format(len(files)))

                for idx in files:
                        try:
                                idx = int(idx)
                        except ValueError:
                                print('[!] Bad value "{:s}" (must be number)'.format(idx), file=sys.stderr)
                                sys.exit(1)
                        if idx < 0 or idx > self.dz_file.getSlice(-1).getIndex():
                                print("[!] Cannot extract out of range slice {:d} (min=0 max={:d})".format(idx, self.dz_file.getSlice(-1).getIndex()), file=sys.stderr)
                                sys.exit(1)

                        cur = idx
                        slice = self.dz_file.getSlice(cur)
                        if slice.getIndex() != None:
                            while slice.getIndex() < idx:
                                cur += idx - slice.getIndex() if slice.getIndex() else 1
                                slice = self.dz_file.getSlice(cur)
                                if slice.getIndex() == None:
                                    slice = self.dz_file.getSlice(idx)

                        name = slice.getSliceName() + ".image"
                        file = io.FileIO(name, "wb")
                        self.dz_file.extractSlice(file, name, cur)
                        file.close()

        def cmdExtractImage(self, files):
                if len(files) > 0:
                        print("[!] Cannot specify specific portions to extract when outputting image", file=sys.stderr)
                        sys.exit(1)
                name = "image.img"
                try:
                        file = io.open(name, "r+b")
                except IOError:
                        file = io.open(name, "wb")
                self.dz_file.extractImage(file, name)
                file.close()

        def main(self):
                global cmd
                args = self.parseArgs()
                cmd = args[0]
                files = args[1]

                if cmd.outdir:
                        self.outdir = cmd.outdir

                self.dz_file = UNDZFile(cmd.dzfile)

                if cmd.listOnly:
                        self.cmdListPartitions()
                        sys.exit(0)

                # Ensure that the output directory exists
                if not os.path.exists(self.outdir):
                        os.makedirs(self.outdir)

                # Change to the output directory
                os.chdir(self.outdir)

                # Extracting slice(s)
                if cmd.extractSlice:
                        self.cmdExtractSlice(files)

                # Extracting chunk-files(s)
                elif cmd.extractChunkfile:
                        self.cmdExtractChunkfile(files)

                # Extract the whole image
                elif cmd.extractImage:
                        self.cmdExtractImage(files)

                # Extracting chunk(s)
                elif cmd.extractChunk:
                        self.cmdExtractChunk(files)

                # Save the header for later reconstruction
                self.dz_file.saveHeader(cmd.dzfile)

if __name__ == "__main__":
        dztools = DZFileTools()
        dztools.main()