forked from Imagelibrary/littlefs
de7564e448
This carves out two more bits in cksum tags to store the "phase" of the
rbyd block (maybe the name is too fancy, this is just the lowest 2 bits
of the block address):
LFSR_TAG_CKSUM 0x300p v-11 ---- ---- -pqq
^ ^
| '-- phase bits
'---- perturb bit
The intention here is to catch mrootanchors that are "out-of-phase",
i.e. they've been shifted by a small number of blocks.
This can happen if we find the wrong mrootanchor (after, say, a magic
scan), and risks filesystem corruption:
formatted
.-----------------'-----------------.
mounted
.-----------------'-----------------.
.--------+--------+--------+--------+ ...
|(erased)| mroot |
| | anchor | ...
| | |
'--------+--------+--------+--------+ ...
Including the lower 2 bits of the block address in cksum tags avoids
this, for up to a 3 block shift (the maximum number of redund
mrootanchors).
---
Note that cksum tags really are the only place we could put these bits.
Anywhere else and they would interfere with the canonical cksum, which
would break error correction. By definition these need to be different
per block.
We include these phase bits in every cksum tag (because it's easier),
but these don't really say much about mdirs that are not the
mrootanchor. Non-anchor mdirs can have arbitrary block addresses,
therefore arbitrary phase bits.
You _might_ be able to do something interesting if you sort the rbyd
addresses and use the index as the phase bits, but that would add quite
a bit of code for questionable benefit...
You could argue this adds noise to our cksums, but:
1. 2 bits seems like a really small amount of noise
2. our cksums are just crc32cs
3. the phase bits humorously never change when you rewrite a block
---
As with any feature this adds code, but only a small amount. I think
it's worth the extra protection:
code stack ctx
before: 35792 2368 636
after: 35824 (+0.1%) 2368 (+0.0%) 636 (+0.0%)
Also added test_mount_incompat_out_of_phase to test this.
The dbg scripts _don't_ error (block mismatch seems likely when
debugging), but dbgrbyd.py at least adds phase mismatch notes in
-l/--log mode.
348 lines
13 KiB
Python
Executable File
348 lines
13 KiB
Python
Executable File
#!/usr/bin/env python3
|
|
|
|
# prevent local imports
|
|
if __name__ == "__main__":
|
|
__import__('sys').path.pop(0)
|
|
|
|
import io
|
|
import math as mt
|
|
import os
|
|
import struct
|
|
import sys
|
|
|
|
|
|
TAG_NULL = 0x0000 ## 0x0000 v--- ---- ---- ----
|
|
TAG_CONFIG = 0x0000 ## 0x00tt v--- ---- -ttt tttt
|
|
TAG_MAGIC = 0x0031 # 0x003r v--- ---- --11 --rr
|
|
TAG_VERSION = 0x0034 # 0x0034 v--- ---- --11 -1--
|
|
TAG_RCOMPAT = 0x0035 # 0x0035 v--- ---- --11 -1-1
|
|
TAG_WCOMPAT = 0x0036 # 0x0036 v--- ---- --11 -11-
|
|
TAG_OCOMPAT = 0x0037 # 0x0037 v--- ---- --11 -111
|
|
TAG_GEOMETRY = 0x0038 # 0x0038 v--- ---- --11 1---
|
|
TAG_FILELIMIT = 0x0039 # 0x0039 v--- ---- --11 1--1
|
|
TAG_NAMELIMIT = 0x003a # 0x003a v--- ---- --11 1-1-
|
|
TAG_GDELTA = 0x0100 ## 0x01tt v--- ---1 -ttt ttrr
|
|
TAG_GRMDELTA = 0x0100 # 0x0100 v--- ---1 ---- ----
|
|
TAG_NAME = 0x0200 ## 0x02tt v--- --1- -ttt tttt
|
|
TAG_BNAME = 0x0200 # 0x0200 v--- --1- ---- ----
|
|
TAG_REG = 0x0201 # 0x0201 v--- --1- ---- ---1
|
|
TAG_DIR = 0x0202 # 0x0202 v--- --1- ---- --1-
|
|
TAG_STICKYNOTE = 0x0203 # 0x0203 v--- --1- ---- --11
|
|
TAG_BOOKMARK = 0x0204 # 0x0204 v--- --1- ---- -1--
|
|
TAG_MNAME = 0x0220 # 0x0220 v--- --1- --1- ----
|
|
TAG_STRUCT = 0x0300 ## 0x03tt v--- --11 -ttt ttrr
|
|
TAG_BRANCH = 0x0300 # 0x030r v--- --11 ---- --rr
|
|
TAG_DATA = 0x0304 # 0x0304 v--- --11 ---- -1--
|
|
TAG_BLOCK = 0x0308 # 0x0308 v--- --11 ---- 1err
|
|
TAG_DID = 0x0314 # 0x0314 v--- --11 ---1 -1--
|
|
TAG_BSHRUB = 0x0318 # 0x0318 v--- --11 ---1 1---
|
|
TAG_BTREE = 0x031c # 0x031c v--- --11 ---1 11rr
|
|
TAG_MROOT = 0x0321 # 0x032r v--- --11 --1- --rr
|
|
TAG_MDIR = 0x0325 # 0x0324 v--- --11 --1- -1rr
|
|
TAG_MTREE = 0x032c # 0x032c v--- --11 --1- 11rr
|
|
TAG_ATTR = 0x0400 ## 0x04aa v--- -1-a -aaa aaaa
|
|
TAG_UATTR = 0x0400 # 0x04aa v--- -1-- -aaa aaaa
|
|
TAG_SATTR = 0x0500 # 0x05aa v--- -1-1 -aaa aaaa
|
|
TAG_SHRUB = 0x1000 ## 0x1kkk v--1 kkkk -kkk kkkk
|
|
TAG_ALT = 0x4000 ## 0x4kkk v1cd kkkk -kkk kkkk
|
|
TAG_B = 0x0000
|
|
TAG_R = 0x2000
|
|
TAG_LE = 0x0000
|
|
TAG_GT = 0x1000
|
|
TAG_CKSUM = 0x3000 ## 0x300p v-11 ---- ---- -pqq
|
|
TAG_PHASE = 0x0003
|
|
TAG_PERTURB = 0x0004
|
|
TAG_NOTE = 0x3100 ## 0x3100 v-11 ---1 ---- ----
|
|
TAG_ECKSUM = 0x3200 ## 0x3200 v-11 --1- ---- ----
|
|
TAG_GCKSUMDELTA = 0x3300 ## 0x3300 v-11 --11 ---- ----
|
|
|
|
|
|
# open with '-' for stdin/stdout
|
|
def openio(path, mode='r', buffering=-1):
|
|
import os
|
|
if path == '-':
|
|
if 'r' in mode:
|
|
return os.fdopen(os.dup(sys.stdin.fileno()), mode, buffering)
|
|
else:
|
|
return os.fdopen(os.dup(sys.stdout.fileno()), mode, buffering)
|
|
else:
|
|
return open(path, mode, buffering)
|
|
|
|
def fromleb128(data, j=0):
|
|
word = 0
|
|
d = 0
|
|
while j+d < len(data):
|
|
b = data[j+d]
|
|
word |= (b & 0x7f) << 7*d
|
|
word &= 0xffffffff
|
|
if not b & 0x80:
|
|
return word, d+1
|
|
d += 1
|
|
return word, d
|
|
|
|
def fromtag(data, j=0):
|
|
d = 0
|
|
tag = struct.unpack('>H', data[j:j+2].ljust(2, b'\0'))[0]; d += 2
|
|
weight, d_ = fromleb128(data, j+d); d += d_
|
|
size, d_ = fromleb128(data, j+d); d += d_
|
|
return tag>>15, tag&0x7fff, weight, size, d
|
|
|
|
# human readable tag repr
|
|
def tagrepr(tag, weight=None, size=None, *,
|
|
global_=False,
|
|
toff=None):
|
|
# null tags
|
|
if (tag & 0x6fff) == TAG_NULL:
|
|
return '%snull%s%s' % (
|
|
'shrub' if tag & TAG_SHRUB else '',
|
|
' w%d' % weight if weight else '',
|
|
' %d' % size if size else '')
|
|
# config tags
|
|
elif (tag & 0x6f00) == TAG_CONFIG:
|
|
return '%s%s%s%s' % (
|
|
'shrub' if tag & TAG_SHRUB else '',
|
|
'magic' if (tag & 0xfff) == TAG_MAGIC
|
|
else 'version' if (tag & 0xfff) == TAG_VERSION
|
|
else 'rcompat' if (tag & 0xfff) == TAG_RCOMPAT
|
|
else 'wcompat' if (tag & 0xfff) == TAG_WCOMPAT
|
|
else 'ocompat' if (tag & 0xfff) == TAG_OCOMPAT
|
|
else 'geometry' if (tag & 0xfff) == TAG_GEOMETRY
|
|
else 'filelimit' if (tag & 0xfff) == TAG_FILELIMIT
|
|
else 'namelimit' if (tag & 0xfff) == TAG_NAMELIMIT
|
|
else 'config 0x%02x' % (tag & 0xff),
|
|
' w%d' % weight if weight else '',
|
|
' %s' % size if size is not None else '')
|
|
# global-state delta tags
|
|
elif (tag & 0x6f00) == TAG_GDELTA:
|
|
if global_:
|
|
return '%s%s%s%s' % (
|
|
'shrub' if tag & TAG_SHRUB else '',
|
|
'grm' if (tag & 0xfff) == TAG_GRMDELTA
|
|
else 'gstate 0x%02x' % (tag & 0xff),
|
|
' w%d' % weight if weight else '',
|
|
' %s' % size if size is not None else '')
|
|
else:
|
|
return '%s%s%s%s' % (
|
|
'shrub' if tag & TAG_SHRUB else '',
|
|
'grmdelta' if (tag & 0xfff) == TAG_GRMDELTA
|
|
else 'gdelta 0x%02x' % (tag & 0xff),
|
|
' w%d' % weight if weight else '',
|
|
' %s' % size if size is not None else '')
|
|
# name tags, includes file types
|
|
elif (tag & 0x6f00) == TAG_NAME:
|
|
return '%s%s%s%s' % (
|
|
'shrub' if tag & TAG_SHRUB else '',
|
|
'bname' if (tag & 0xfff) == TAG_BNAME
|
|
else 'reg' if (tag & 0xfff) == TAG_REG
|
|
else 'dir' if (tag & 0xfff) == TAG_DIR
|
|
else 'stickynote' if (tag & 0xfff) == TAG_STICKYNOTE
|
|
else 'bookmark' if (tag & 0xfff) == TAG_BOOKMARK
|
|
else 'mname' if (tag & 0xfff) == TAG_MNAME
|
|
else 'name 0x%02x' % (tag & 0xff),
|
|
' w%d' % weight if weight else '',
|
|
' %s' % size if size is not None else '')
|
|
# structure tags
|
|
elif (tag & 0x6f00) == TAG_STRUCT:
|
|
return '%s%s%s%s' % (
|
|
'shrub' if tag & TAG_SHRUB else '',
|
|
'branch' if (tag & 0xfff) == TAG_BRANCH
|
|
else 'data' if (tag & 0xfff) == TAG_DATA
|
|
else 'block' if (tag & 0xfff) == TAG_BLOCK
|
|
else 'did' if (tag & 0xfff) == TAG_DID
|
|
else 'bshrub' if (tag & 0xfff) == TAG_BSHRUB
|
|
else 'btree' if (tag & 0xfff) == TAG_BTREE
|
|
else 'mroot' if (tag & 0xfff) == TAG_MROOT
|
|
else 'mdir' if (tag & 0xfff) == TAG_MDIR
|
|
else 'mtree' if (tag & 0xfff) == TAG_MTREE
|
|
else 'struct 0x%02x' % (tag & 0xff),
|
|
' w%d' % weight if weight else '',
|
|
' %s' % size if size is not None else '')
|
|
# custom attributes
|
|
elif (tag & 0x6e00) == TAG_ATTR:
|
|
return '%s%sattr 0x%02x%s%s' % (
|
|
'shrub' if tag & TAG_SHRUB else '',
|
|
's' if tag & 0x100 else 'u',
|
|
((tag & 0x100) >> 1) + (tag & 0xff),
|
|
' w%d' % weight if weight else '',
|
|
' %s' % size if size is not None else '')
|
|
# alt pointers
|
|
elif tag & TAG_ALT:
|
|
return 'alt%s%s 0x%03x%s%s' % (
|
|
'r' if tag & TAG_R else 'b',
|
|
'gt' if tag & TAG_GT else 'le',
|
|
tag & 0x0fff,
|
|
' w%d' % weight if weight is not None else '',
|
|
' 0x%x' % (0xffffffff & (toff-size))
|
|
if size and toff is not None
|
|
else ' -%d' % size if size
|
|
else '')
|
|
# checksum tags
|
|
elif (tag & 0x7f00) == TAG_CKSUM:
|
|
return 'cksum%s%s%s%s%s' % (
|
|
'q%d' % (tag & 0x3),
|
|
'p' if tag & TAG_PERTURB else '',
|
|
' 0x%02x' % (tag & 0xff) if tag & 0xf8 else '',
|
|
' w%d' % weight if weight else '',
|
|
' %s' % size if size is not None else '')
|
|
# note tags
|
|
elif (tag & 0x7f00) == TAG_NOTE:
|
|
return 'note%s%s%s' % (
|
|
' 0x%02x' % (tag & 0xff) if tag & 0xff else '',
|
|
' w%d' % weight if weight else '',
|
|
' %s' % size if size is not None else '')
|
|
# erased-state checksum tags
|
|
elif (tag & 0x7f00) == TAG_ECKSUM:
|
|
return 'ecksum%s%s%s' % (
|
|
' 0x%02x' % (tag & 0xff) if tag & 0xff else '',
|
|
' w%d' % weight if weight else '',
|
|
' %s' % size if size is not None else '')
|
|
# global-checksum delta tags
|
|
elif (tag & 0x7f00) == TAG_GCKSUMDELTA:
|
|
if global_:
|
|
return 'gcksum%s%s%s' % (
|
|
' 0x%02x' % (tag & 0xff) if tag & 0xff else '',
|
|
' w%d' % weight if weight else '',
|
|
' %s' % size if size is not None else '')
|
|
else:
|
|
return 'gcksumdelta%s%s%s' % (
|
|
' 0x%02x' % (tag & 0xff) if tag & 0xff else '',
|
|
' w%d' % weight if weight else '',
|
|
' %s' % size if size is not None else '')
|
|
# unknown tags
|
|
else:
|
|
return '0x%04x%s%s' % (
|
|
tag,
|
|
' w%d' % weight if weight is not None else '',
|
|
' %d' % size if size is not None else '')
|
|
|
|
|
|
def list_tags():
|
|
# here be magic, parse our script's source to get to the tag comments
|
|
import inspect
|
|
import re
|
|
tags = []
|
|
tag_pattern = re.compile(
|
|
'^(?P<name>TAG_[^ ]*) *= *(?P<tag>[^ #]+) *#+ *(?P<comment>.*)$')
|
|
for line in inspect.getsourcelines(
|
|
inspect.getmodule(inspect.currentframe()))[0]:
|
|
m = tag_pattern.match(line)
|
|
if m:
|
|
tags.append(m.groups())
|
|
|
|
# find widths for alignment
|
|
w = [0]
|
|
for n, t, c in tags:
|
|
w[0] = max(w[0], len('LFSR_'+n))
|
|
|
|
# print
|
|
for n, t, c in tags:
|
|
print('%-*s %s' % (
|
|
w[0], 'LFSR_'+n,
|
|
c))
|
|
|
|
def dbg_tags(data, *,
|
|
word_bits=32):
|
|
# figure out tag size in bytes
|
|
if word_bits != 0:
|
|
n = 2 + 2*mt.ceil(word_bits / 7)
|
|
|
|
lines = []
|
|
# interpret as ints?
|
|
if not isinstance(data, bytes):
|
|
for tag in data:
|
|
lines.append((
|
|
' '.join('%02x' % b for b in struct.pack('>H', tag)),
|
|
tagrepr(tag)))
|
|
|
|
# interpret as bytes?
|
|
else:
|
|
j = 0
|
|
while j < len(data):
|
|
# bounded tags?
|
|
if word_bits != 0:
|
|
v, tag, w, size, d = fromtag(data[j:j+n])
|
|
# unbounded?
|
|
else:
|
|
v, tag, w, size, d = fromtag(data, j)
|
|
|
|
lines.append((
|
|
' '.join('%02x' % b for b in data[j:j+d]),
|
|
tagrepr(tag, w, size)))
|
|
j += d
|
|
|
|
# skip attached data if there is any
|
|
if not tag & TAG_ALT:
|
|
j += size
|
|
|
|
# figure out widths
|
|
w = [0]
|
|
for l in lines:
|
|
w[0] = max(w[0], len(l[0]))
|
|
|
|
# then print results
|
|
for l in lines:
|
|
print('%-*s %s' % (
|
|
w[0], l[0],
|
|
l[1]))
|
|
|
|
def main(tags, *,
|
|
list=False,
|
|
hex=False,
|
|
input=None,
|
|
word_bits=32):
|
|
list_ = list; del list
|
|
hex_ = hex; del hex
|
|
|
|
# list all known tags
|
|
if list_:
|
|
list_tags()
|
|
|
|
# interpret as a sequence of hex bytes
|
|
elif hex_:
|
|
bytes_ = [b for tag in tags for b in tag.split()]
|
|
dbg_tags(bytes(int(b, 16) for b in bytes_),
|
|
word_bits=word_bits)
|
|
|
|
# parse tags in a file
|
|
elif input:
|
|
with openio(input, 'rb') as f:
|
|
dbg_tags(f.read(),
|
|
word_bits=word_bits)
|
|
|
|
# default to interpreting as ints
|
|
else:
|
|
dbg_tags((int(tag, 0) for tag in tags),
|
|
word_bits=word_bits)
|
|
|
|
|
|
if __name__ == "__main__":
|
|
import argparse
|
|
import sys
|
|
parser = argparse.ArgumentParser(
|
|
description="Decode littlefs tags.",
|
|
allow_abbrev=False)
|
|
parser.add_argument(
|
|
'tags',
|
|
nargs='*',
|
|
help="Tags to decode.")
|
|
parser.add_argument(
|
|
'-l', '--list',
|
|
action='store_true',
|
|
help="List all known tags.")
|
|
parser.add_argument(
|
|
'-x', '--hex',
|
|
action='store_true',
|
|
help="Interpret as a sequence of hex bytes.")
|
|
parser.add_argument(
|
|
'-i', '--input',
|
|
help="Read tags from this file. Can use - for stdin.")
|
|
parser.add_argument(
|
|
'-w', '--word-bits',
|
|
nargs='?',
|
|
type=lambda x: int(x, 0),
|
|
const=0,
|
|
help="Word size in bits. 0 is unbounded. Defaults to 32.")
|
|
sys.exit(main(**{k: v
|
|
for k, v in vars(parser.parse_intermixed_args()).items()
|
|
if v is not None}))
|