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#!/usr/bin/env python3
import struct
import sys
import json
import io
import itertools as it
from readmdir import Tag, MetadataPair
def main(args):
superblock = None
gstate = b'\0\0\0\0\0\0\0\0\0\0\0\0'
dirs = []
mdirs = []
corrupted = []
cycle = False
with open(args.disk, 'rb') as f:
tail = (args.block1, args.block2)
hard = False
while True:
for m in it.chain((m for d in dirs for m in d), mdirs):
if set(m.blocks) == set(tail):
# cycle detected
cycle = m.blocks
if cycle:
break
# load mdir
data = []
blocks = {}
for block in tail:
f.seek(block * args.block_size)
data.append(f.read(args.block_size)
.ljust(args.block_size, b'\xff'))
blocks[id(data[-1])] = block
mdir = MetadataPair(data)
mdir.blocks = tuple(blocks[id(p.data)] for p in mdir.pair)
# fetch some key metadata as a we scan
try:
mdir.tail = mdir[Tag('tail', 0, 0)]
if mdir.tail.size != 8 or mdir.tail.data == 8*b'\xff':
mdir.tail = None
except KeyError:
mdir.tail = None
# have superblock?
try:
nsuperblock = mdir[
Tag(0x7ff, 0x3ff, 0), Tag('superblock', 0, 0)]
superblock = nsuperblock, mdir[Tag('inlinestruct', 0, 0)]
except KeyError:
pass
# have gstate?
try:
ngstate = mdir[Tag('movestate', 0, 0)]
gstate = bytes((a or 0) ^ (b or 0)
for a,b in it.zip_longest(gstate, ngstate.data))
except KeyError:
pass
# corrupted?
if not mdir:
corrupted.append(mdir)
# add to directories
mdirs.append(mdir)
if mdir.tail is None or not mdir.tail.is_('hardtail'):
dirs.append(mdirs)
mdirs = []
if mdir.tail is None:
break
tail = struct.unpack('<II', mdir.tail.data)
hard = mdir.tail.is_('hardtail')
# find paths
dirtable = {}
for dir in dirs:
dirtable[frozenset(dir[0].blocks)] = dir
pending = [("/", dirs[0])]
while pending:
path, dir = pending.pop(0)
for mdir in dir:
for tag in mdir.tags:
if tag.is_('dir'):
try:
npath = tag.data.decode('utf8')
dirstruct = mdir[Tag('dirstruct', tag.id, 0)]
nblocks = struct.unpack('<II', dirstruct.data)
nmdir = dirtable[frozenset(nblocks)]
pending.append(((path + '/' + npath), nmdir))
except KeyError:
pass
dir[0].path = path.replace('//', '/')
# print littlefs + version info
version = ('?', '?')
if superblock:
version = tuple(reversed(
struct.unpack('<HH', superblock[1].data[0:4].ljust(4, b'\xff'))))
print("%-47s%s" % ("littlefs v%s.%s" % version,
"data (truncated, if it fits)"
if not any([args.no_truncate, args.log, args.all]) else ""))
# print gstate
print("gstate 0x%s" % ''.join('%02x' % c for c in gstate))
tag = Tag(struct.unpack('<I', gstate[0:4].ljust(4, b'\xff'))[0])
blocks = struct.unpack('<II', gstate[4:4+8].ljust(8, b'\xff'))
if tag.size or not tag.isvalid:
print(" orphans >=%d" % max(tag.size, 1))
if tag.type:
print(" move dir {%#x, %#x} id %d" % (
blocks[0], blocks[1], tag.id))
# print mdir info
for i, dir in enumerate(dirs):
print("dir %s" % (json.dumps(dir[0].path)
if hasattr(dir[0], 'path') else '(orphan)'))
for j, mdir in enumerate(dir):
print("mdir {%#x, %#x} rev %d (was %d)%s%s" % (
mdir.blocks[0], mdir.blocks[1], mdir.rev, mdir.pair[1].rev,
' (corrupted!)' if not mdir else '',
' -> {%#x, %#x}' % struct.unpack('<II', mdir.tail.data)
if mdir.tail else ''))
f = io.StringIO()
if args.log:
mdir.dump_log(f, truncate=not args.no_truncate)
elif args.all:
mdir.dump_all(f, truncate=not args.no_truncate)
else:
mdir.dump_tags(f, truncate=not args.no_truncate)
lines = list(filter(None, f.getvalue().split('\n')))
for k, line in enumerate(lines):
print("%s %s" % (
' ' if j == len(dir)-1 else
'v' if k == len(lines)-1 else
'|',
line))
errcode = 0
for mdir in corrupted:
errcode = errcode or 1
print("*** corrupted mdir {%#x, %#x}! ***" % (
mdir.blocks[0], mdir.blocks[1]))
if cycle:
errcode = errcode or 2
print("*** cycle detected {%#x, %#x}! ***" % (
cycle[0], cycle[1]))
return errcode
if __name__ == "__main__":
import argparse
import sys
parser = argparse.ArgumentParser(
description="Dump semantic info about the metadata tree in littlefs")
parser.add_argument('disk',
help="File representing the block device.")
parser.add_argument('block_size', type=lambda x: int(x, 0),
help="Size of a block in bytes.")
parser.add_argument('block1', nargs='?', default=0,
type=lambda x: int(x, 0),
help="Optional first block address for finding the superblock.")
parser.add_argument('block2', nargs='?', default=1,
type=lambda x: int(x, 0),
help="Optional second block address for finding the superblock.")
parser.add_argument('-l', '--log', action='store_true',
help="Show tags in log.")
parser.add_argument('-a', '--all', action='store_true',
help="Show all tags in log, included tags in corrupted commits.")
parser.add_argument('-T', '--no-truncate', action='store_true',
help="Show the full contents of files/attrs/tags.")
sys.exit(main(parser.parse_args()))
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