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8kzenrecover.py
#!/usr/bin/python
# Copyright 2007 by Tobia Conforto <tobia.conforto@gmail.com>
#
# 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 2 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/
# Versions: 0.1 2007-08-13 Initial release
# 0.2 2008-05-12 Small fixes for Zen Xtra models
# 0.3 2009-02-23 Zen Vision M compatible version (Leho Kraav <leho@kraav.com>)
from __future__ import division
import sys, os, codecs, array, time, operator, getopt
import LRU
class CFS:
# 32k cluster on visionm30
clusterSize = 0x8000
cacheMem = 10 * 2**20 # keep 20MB of recently read clusters in ram
def __init__(self, filename, offset = 0):
'''Filename and optional offset where the CFS filesystem begins
(offset of cluster -1, the one filled with 0xff)'''
self.image = file(filename)
self.offset = offset
self.clusterCache = LRU.LRU(self.cacheMem // self.clusterSize)
def __getitem__(self, key):
'''Get the nth CFS cluster from the image and cache it for later usage.
Accepts simple slices of clusters, but doesn't process negative indices.
In any case it returns the requested data as a byte string.'''
if isinstance(key, slice):
cstart, cstop = key.start, key.stop
else:
cstart, cstop = key, key + 1
data = ''
for cluster in range(cstart, cstop):
if cluster not in self.clusterCache:
self.image.seek(self.offset + (cluster + 1) * self.clusterSize)
self.clusterCache[cluster] = self.image.read(self.clusterSize)
data += self.clusterCache[cluster]
return data
def get_byteswapped_data(self, cluster):
'''Get the nth CFS cluster from the image, without caching it.
Swap the position of every two bytes and return it as an array object.
This method is designed for bulk file retrieving.'''
a = array.array('H')
self.image.seek(self.offset + (cluster + 1) * self.clusterSize)
a.fromfile(self.image, self.clusterSize // 2)
# visionm 30 doesnt need byte swapping
# a.byteswap()
return a
def inode(self, cluster):
return CFSInode(self, cluster)
#def pdp_uint32(data, offset = 0):
# o2, o1, o4, o3 = map(ord, data[offset : offset + 4])
# return (o1 << 24) | (o2 << 16) | (o3 << 8) | o4
def pdp_uint32(data, offset = 0):
o4, o3, o2, o1 = map(ord, data[offset : offset + 4])
return (o1 << 24) | (o2 << 16) | (o3 << 8) | o4
def pdp_uint16(data, offset = 0):
o2, o1 = map(ord, data[offset : offset + 2])
return (o1 << 8) | o2
def ucs2string(data, offset, length): # length in bytes
return codecs.utf_16_le_decode(data[offset : offset + length])[0]
def pdp_getbit(bitmap, bit_no):
return (pdp_uint32(bitmap, bit_no // 32 * 4) >> (bit_no % 32)) & 1
class CFSInode:
filename = '(no filename)'
filesize = 0
path = []
def __init__(self, cfs, cluster):
self.cluster = cluster
self.cfs = cfs
inode = cfs[cluster]
# reading misc flags and values
print "pdp_uint: %x" % pdp_uint32(inode[4:8])
print "cluster: %x" % cluster
assert pdp_uint32(inode[4:8]) == cluster # self-reference
self.serial = pdp_uint32(inode, 0x78)
# reading metadata
count_metadata = pdp_uint32(inode, 0x7c)
offset = 0x80
self.metadata = {}
for i in range(count_metadata):
assert pdp_uint16(inode, offset) == 3
length = pdp_uint16(inode, offset + 2)
tag = ucs2string(inode, offset + 4, 4)
self.metadata[tag] = inode[offset + 10 : offset + 10 + length]
# byte reordering issue, 07 -> 70, 0= -> =0, 0> -> >0
# but we cannot figure out where to get path info, tag '51' doesnt work
if tag == '70':
self.filename = ucs2string(inode, offset + 10, length - 2)
elif tag == '51':
self.path = ucs2string(inode, offset + 10, length - 2).strip('\\').split('\\')
elif tag == '>0':
self.filesize = pdp_uint32(inode, offset + 10)
offset += 10 + length
# collecting flat list of data clusters
self.dataclusters = []
pointerclusters = []
for off in range(0x20, 0x4c + 1, 4):
c = pdp_uint32(inode, off)
if c != 0xFFFFFFFFL:
self.dataclusters.append(c)
second_class_chain = pdp_uint32(inode, 0x58)
if second_class_chain != 0xFFFFFFFFL:
pointerclusters.append(second_class_chain)
third_class_chain = pdp_uint32(inode, 0x64)
# change 0x2000 to 0x8000 -> we might have 32k clusters on visionm 30g
if third_class_chain != 0xFFFFFFFFL:
for off in range(0, 0x8000, 4):
c = pdp_uint32(cfs[third_class_chain], off)
if c == 0xFFFFFFFFL:
break
pointerclusters.append(c)
# once again, 32k cluster
for pnt in pointerclusters:
for off in range(0, 0x8000, 4):
c = pdp_uint32(cfs[pnt], off)
if c == 0xFFFFFFFFL:
break
self.dataclusters.append(c)
# reading directory entries
if not self.metadata: # any better way of telling dirs and files apart?
count_direntries = pdp_uint32(self, 8)
self.direntries = []
found = 0
# since clusters are 4 times bigger now, we need % 2 and // 2 instead of ... 8
assert len(self.dataclusters) % 2 == 0
for block_no in range(len(self.dataclusters) // 2):
block = self[block_no * 0x10000 : block_no * 0x10000 + 0x10000]
bitmap = block[16 : 16 + 204]
for n in range(1632):
if pdp_getbit(bitmap, n):
off = 220 + n * 40
self.direntries.append(CFSDirEntry(cfs, block[off : off + 40]))
found += 1
assert found == count_direntries
def __getitem__(self, key):
'''Returns the given byte (or byte slice) from the file contents.'''
if isinstance(key, slice):
bstart, bstop = key.start, key.stop
else:
bstart, bstop = key, key + 1
cs = self.cfs.clusterSize
cstart = bstart // cs
cstop = (bstop - 1) // cs + 1
data = ''.join([ self.cfs[x] for x in self.dataclusters[cstart : cstop] ])
return data[bstart - cs * cstart : bstop - cs * cstart]
class CFSDirEntry:
def __init__(self, cfs, entrydata):
self.cluster = pdp_uint32(entrydata) # cluster no. of the inode
# length of full filename
self.len_filename = pdp_uint16(entrydata, 4)
# first 15 chars of filename
self.shortname = ucs2string(entrydata, 8, min(30, self.len_filename * 2))
if __name__ == '__main__':
# commandline arguments
optlist, args = getopt.gnu_getopt(sys.argv[1:], 'o:')
opts = dict(optlist)
offset = int(opts.get('-o', 20 * 2**20))
if len(args) != 3:
print 'Usage: zenrecover.py [-o OFFSET] DISK_OR_IMAGE SECTION OUTPUT_DIR'
print 'DISK_OR_IMAGE is the disk containing the filesystem, or an image thereof'
print 'OFFSET is the offset at which the filesystem starts (in bytes, default 20M)'
print 'SECTION is the section of the filesystem to recover: "archives" or "songs"'
print 'OUTPUT_DIR is the directory in which to place the recovered files'
sys.exit(1)
cfs = CFS(args[0], offset)
section = args[1]
outdir = args[2]
# find the root inode
rootinode = None
for c in range(4, 0x10000):
if pdp_uint32(cfs[c][:4]) == 0x3bbe0ad9:
print "Found inode at cluster 0x%x" % c
i = cfs.inode(c)
if i.serial != 0xFFFFFFFFL:
print "Found inode at cluster 0x%x, but serial number is not -1" % c
continue
rootinode = i
break
if not rootinode:
raise "Could not find the root inode"
# find the root directories
root = {}
for entry in rootinode.direntries:
root[entry.shortname] = entry.cluster
print root
# begin recovery
dirinode = cfs.inode(root[section])
os.makedirs(outdir)
lastfiles = [(1,1)] # timing of latest few files recovered (size in bytes, time in secs)
t = len(dirinode.direntries)
for i, entry in enumerate(dirinode.direntries):
if entry.shortname != '.':
t0 = time.time()
inode = cfs.inode(entry.cluster)
print
m=inode.metadata
for j in m:
if len(m[j])==4:
print repr(j), pdp_uint32(m[j])
else:
print repr(j), repr(''.join([m[j][x] for x in range(0,len(m[j]),2)]))
print '\r%d%% %.1fMB/s "%s" (%.1fMB)\033[K' % (
i * 100 // t,
operator.truediv(*map(sum, zip(*lastfiles))) / 2**20,
inode.filename[:50],
inode.filesize / 2**20),
sys.stdout.flush()
path = os.path.join(outdir, *inode.path)
try:
os.makedirs(path)
except:
pass
f = file(os.path.join(path, inode.filename), 'w')
remaining = inode.filesize
for c in inode.dataclusters:
if remaining >= cfs.clusterSize:
cfs.get_byteswapped_data(c).tofile(f)
else:
f.write(cfs.get_byteswapped_data(c).tostring()[:remaining])
remaining -= min(cfs.clusterSize, remaining)
f.close()
assert remaining == 0
if len(lastfiles) >= 32: #transfer speed is calculated on latest 32 files
lastfiles.pop(0)
lastfiles.append((inode.filesize, time.time() - t0))
print '\rDone.\033[K'
@ben-xo

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ben-xo commented May 7, 2014

Hello! I can't get this to work with python 2 (unknown module LRU) or python 3 (syntax error print "...") - any tips for getting LRU with python 2?

(I have a hard disk dump from a Creative NOMAD Jukebox that I'm trying to extract)

^^ no matter - the (only) fork of this gist worked!

@tobia

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tobia commented Jul 19, 2016

@ben-xo It's definitely for Python 2, but you need to place the LRU.py file in the same directory as this one, otherwise it won't find it.

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mattegger commented Nov 15, 2018

Hi there! Thanks for sharing this. Where can I find LRU.py? What module is it from?

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