Files
littlefs/scripts/dbgrbyd.py
Christopher Haster a511696bad Added ability to bypass rbyd fetch during B-tree lookups
This is an absurd optimization that stems from the observation that the
branch encoding for the inner-rbyds in a B-tree is enough information to
jump directly to the trunk of the rbyd without needing an lfsr_rbyd_fetch.

This results in a pretty ridiculous performance jump from O(m log_m(n/m))
to O(log(m) log_m(n/m)).

If the complexity analysis isn't impressive enough, look at some rough
benchmarking of read operations for 4KiB-block, 1K-entry B-trees:

   12KiB ^     ::  :. :: .: .: :. : .: :. : : .. : : . : .: : : :
         |    .:: .::.::.:: ::.::::::::::::.::::::::.::::::::::::.
         |    : :::':: ::'::'::':: :' :':: :'::::::::': ::::::': :
before   |  ::: ::' :' :' :: :' '' '  ' '' : : : '' ' ' '
         | :::            ''
         |:
      0B :'------------------------------------------------------>

  .17KiB ^               ............:::::::::::::::::::::::::::::
         |   .   .....:::::'''''''''  '         '          '
         |  .::::::::::::
after    |  :':''
         |.::
         .:'
      0B :------------------------------------------------------->
         0                                                      1K

In order for this to work, the branch encoding did need to be tweaked
slightly. Before it stored block+off, now it stores block+trunk where
"trunk" is the offset of the entry point into the rbyd tree. Both off
and trunk are enough info to know when to stop fetching, if necessary,
but trunk allows lookups to jump directly into the branches rbyd tree
without a fetch.

With the change to trunk, lfsr_rbyd_fetch has also be extended to allow
fetching of any internal trunks, not just the last trunk in the commit.
This is very useful for dbgrbyd.py, but doesn't currently have a use in
littlefs itself. But it's at least valuable to have the feature available
in case it does become useful.

Note that two cases still requires the slower O(m log_m(n/m)) lookup
with lfsr_rbyd_fetch:

1. Name lookups, since we currently use a linear-search O(m) to find names.

2. Validating B-tree rbyd's, which requires a linear fetch O(m) to
   validate the checksums. We will need to do this at least once
   after mount.

It's also worth mentioning this will likely have a large impact on B-tree
traversal speed. Which is huge as I am expecting B-tree traversal to be
the main bottleneck once garbage-collection (or its replacement) is
involved.
2023-04-14 00:51:34 -05:00

960 lines
31 KiB
Python
Executable File

#!/usr/bin/env python3
import bisect
import collections as co
import itertools as it
import math as m
import os
import struct
COLORS = [
'34', # blue
'31', # red
'32', # green
'35', # purple
'33', # yellow
'36', # cyan
]
TAG_UNR = 0x0002
TAG_NAME = 0x1000
TAG_BNAME = 0x1000
TAG_REG = 0x1010
TAG_DIR = 0x1020
TAG_STRUCT = 0x3000
TAG_INLINED = 0x3000
TAG_BLOCK = 0x3100
TAG_BRANCH = 0x3200
TAG_BTREE = 0x3300
TAG_UATTR = 0x4000
TAG_ALT = 0x0008
TAG_CRC = 0x0004
TAG_FCRC = 0x1004
def rbydaddr(s):
if '.' in s:
s = s.strip()
b = 10
if s.startswith('0x') or s.startswith('0X'):
s = s[2:]
b = 16
elif s.startswith('0o') or s.startswith('0O'):
s = s[2:]
b = 8
elif s.startswith('0b') or s.startswith('0B'):
s = s[2:]
b = 2
s0, s1 = s.split('.', 1)
return int(s0, b), int(s1, b)
else:
return int(s, 0)
def crc32c(data, crc=0):
crc ^= 0xffffffff
for b in data:
crc ^= b
for j in range(8):
crc = (crc >> 1) ^ ((crc & 1) * 0x82f63b78)
return 0xffffffff ^ crc
def fromle16(data):
return struct.unpack('<H', data[0:2].ljust(2, b'\0'))[0]
def fromle32(data):
return struct.unpack('<I', data[0:4].ljust(4, b'\0'))[0]
def fromleb128(data):
word = 0
for i, b in enumerate(data):
word |= ((b & 0x7f) << 7*i)
word &= 0xffffffff
if not b & 0x80:
return word, i+1
return word, len(data)
def fromtag(data):
tag = fromle16(data)
weight, d = fromleb128(data[2:])
size, d_ = fromleb128(data[2+d:])
return tag&1, tag&~1, weight, size, 2+d+d_
def popc(x):
return bin(x).count('1')
def xxd(data, width=16, crc=False):
for i in range(0, len(data), width):
yield '%-*s %-*s' % (
3*width,
' '.join('%02x' % b for b in data[i:i+width]),
width,
''.join(
b if b >= ' ' and b <= '~' else '.'
for b in map(chr, data[i:i+width])))
def tagrepr(tag, w, size, off=None):
if (tag & 0xfffe) == TAG_UNR:
return 'unr%s%s' % (
' w%d' % w if w else '',
' %d' % size if size else '')
elif (tag & 0xf00c) == TAG_NAME:
return '%s%s%s %d' % (
'rm' if tag & 0x2 else '',
'bname' if (tag & 0xfffe) == TAG_BNAME
else 'reg' if (tag & 0xfffe) == TAG_REG
else 'dir' if (tag & 0xfffe) == TAG_DIR
else 'name 0x%02x' % ((tag & 0x0ff0) >> 4),
' w%d' % w if w else '',
size)
elif (tag & 0xf00c) == TAG_STRUCT:
return '%s%s%s %d' % (
'rm' if tag & 0x2 else '',
'inlined' if (tag & 0xfffe) == TAG_INLINED
else 'block' if (tag & 0xfffe) == TAG_BLOCK
else 'branch' if (tag & 0xfffe) == TAG_BRANCH
else 'btree' if (tag & 0xfffe) == TAG_BTREE
else 'struct 0x%02x' % ((tag & 0x0ff0) >> 4),
' w%d' % w if w else '',
size)
elif (tag & 0xf00c) == TAG_UATTR:
return '%suattr 0x%02x%s%s' % (
'rm' if tag & 0x2 else '',
(tag & 0x0ff0) >> 4,
' w%d' % w if w else '',
' %d' % size if not tag & 0x2 or size else '')
elif (tag & 0xf00e) == TAG_CRC:
return 'crc%x%s %d' % (
1 if tag & 0x10 else 0,
' 0x%x' % w if w > 0 else '',
size)
elif (tag & 0xfffe) == TAG_FCRC:
return 'fcrc%s %d' % (
' 0x%x' % w if w > 0 else '',
size)
elif tag & 0x8:
return 'alt%s%s 0x%x w%d %s' % (
'r' if tag & 0x2 else 'b',
'gt' if tag & 0x4 else 'le',
tag & 0xfff0,
w,
'0x%x' % (0xffffffff & (off-size))
if off is not None
else '-%d' % off)
else:
return '0x%04x w%d %d' % (tag, w, size)
def show_log(data, block_size, rev, off, weight, *,
color=False,
**args):
crc = crc32c(data[0:4])
# preprocess jumps
if args.get('jumps'):
jumps = []
j_ = 4
while j_ < (block_size if args.get('all') else off):
j = j_
v, tag, w, size, d = fromtag(data[j_:])
j_ += d
if not tag & 0x8:
j_ += size
if tag & 0x8:
# figure out which alt color
if tag & 0x2:
_, ntag, _, _, _ = fromtag(data[j_:])
if ntag & 0x2:
jumps.append((j, j-size, 0, 'y'))
else:
jumps.append((j, j-size, 0, 'r'))
else:
jumps.append((j, j-size, 0, 'b'))
# figure out x-offsets to avoid collisions between jumps
for j in range(len(jumps)):
a, b, _, c = jumps[j]
x = 0
while any(
max(a, b) >= min(a_, b_)
and max(a_, b_) >= min(a, b)
and x == x_
for a_, b_, x_, _ in jumps[:j]):
x += 1
jumps[j] = a, b, x, c
def jumprepr(j):
# render jumps
chars = {}
for a, b, x, c in jumps:
c_start = (
'\x1b[33m' if color and c == 'y'
else '\x1b[31m' if color and c == 'r'
else '\x1b[90m' if color
else '')
c_stop = '\x1b[m' if color else ''
if j == a:
for x_ in range(2*x+1):
chars[x_] = '%s-%s' % (c_start, c_stop)
chars[2*x+1] = '%s\'%s' % (c_start, c_stop)
elif j == b:
for x_ in range(2*x+1):
chars[x_] = '%s-%s' % (c_start, c_stop)
chars[2*x+1] = '%s.%s' % (c_start, c_stop)
chars[0] = '%s<%s' % (c_start, c_stop)
elif j >= min(a, b) and j <= max(a, b):
chars[2*x+1] = '%s|%s' % (c_start, c_stop)
return ''.join(chars.get(x, ' ')
for x in range(max(chars.keys(), default=0)+1))
# preprocess lifetimes
lifetime_width = 0
if args.get('lifetimes'):
class Lifetime:
color_i = 0
def __init__(self, j):
self.origin = j
self.tags = set()
self.color = COLORS[self.__class__.color_i]
self.__class__.color_i = (
self.__class__.color_i + 1) % len(COLORS)
def add(self, j):
self.tags.add(j)
def __bool__(self):
return bool(self.tags)
# first figure out where each id comes from
weights = []
lifetimes = []
def index(weights, id):
for i, w in enumerate(weights):
if id < w:
return i, id
id -= w
return len(weights), 0
checkpoint_js = [0]
checkpoints = [([], [], set(), set(), set())]
def checkpoint(j, weights, lifetimes, grows, shrinks, tags):
checkpoint_js.append(j)
checkpoints.append((
weights.copy(), lifetimes.copy(),
grows, shrinks, tags))
lower_, upper_ = 0, 0
weight_ = 0
wastrunk = False
j_ = 4
while j_ < (block_size if args.get('all') else off):
j = j_
v, tag, w, size, d = fromtag(data[j_:])
j_ += d
if not tag & 0x8:
j_ += size
# find trunk
if not wastrunk and (tag & 0xc) != 0x4:
lower_, upper_ = 0, 0
wastrunk = not not tag & 0x8
# keep track of weight
if tag & 0x8:
if tag & 0x4:
upper_ += w
else:
lower_ += w
elif (tag & 0xc) == 0x0:
delta = (lower_+upper_+w) - weight_
weight_ = lower_+upper_+w
id = lower_+w-1
# note we ignore out-of-bounds here for debugging
if delta > 0:
# grow lifetimes
i, id_ = index(weights, lower_)
if id_ > 0:
weights[i:i+1] = [id_, delta, weights[i]-id_]
lifetimes[i:i+1] = [
lifetimes[i], Lifetime(j), lifetimes[i]]
else:
weights[i:i] = [delta]
lifetimes[i:i] = [Lifetime(j)]
checkpoint(j, weights, lifetimes, {i}, set(), {i})
elif delta < 0:
# shrink lifetimes
i, id_ = index(weights, lower_)
delta_ = -delta
weights_ = weights.copy()
lifetimes_ = lifetimes.copy()
shrinks = set()
while delta_ > 0 and i < len(weights_):
if weights_[i] > delta_:
delta__ = min(delta_, weights_[i]-id_)
delta_ -= delta__
weights_[i] -= delta__
i += 1
id_ = 0
else:
delta_ -= weights_[i]
weights_[i:i+1] = []
lifetimes_[i:i+1] = []
shrinks.add(i + len(shrinks))
checkpoint(j, weights, lifetimes, set(), shrinks, {i})
weights = weights_
lifetimes = lifetimes_
if not tag & 0x2 and id >= 0:
# attach tag to lifetime
i, id_ = index(weights, id)
if i < len(weights):
lifetimes[i].add(j)
if delta == 0:
checkpoint(j, weights, lifetimes, set(), set(), {i})
lifetime_width = 2*max((
sum(1 for lifetime in lifetimes if lifetime)
for _, lifetimes, _, _, _ in checkpoints),
default=0)
def lifetimerepr(j):
x = bisect.bisect(checkpoint_js, j)-1
j_ = checkpoint_js[x]
weights, lifetimes, grows, shrinks, tags = checkpoints[x]
reprs = []
colors = []
was = None
for i, (w, lifetime) in enumerate(zip(weights, lifetimes)):
# skip lifetimes with no tags and shrinks
if not lifetime or (j != j_ and i in shrinks):
if i in grows or i in shrinks or i in tags:
tags = tags.copy()
tags.add(i+1)
continue
if j == j_ and i in grows:
reprs.append('.')
was = 'grow'
elif j == j_ and i in shrinks:
reprs.append('\'')
was = 'shrink'
elif j == j_ and i in tags:
reprs.append('* ')
elif was == 'grow':
reprs.append('\\ ')
elif was == 'shrink':
reprs.append('/ ')
else:
reprs.append('| ')
colors.append(lifetime.color)
return '%s%*s' % (
''.join('%s%s%s' % (
'\x1b[%sm' % c if color else '',
r,
'\x1b[m' if color else '')
for r, c in zip(reprs, colors)),
lifetime_width - sum(len(r) for r in reprs), '')
# print header
w_width = 2*m.ceil(m.log10(max(1, weight)+1))+1
print('%-8s %*s%-*s %-22s %s' % (
'off',
lifetime_width, '',
w_width, 'ids',
'tag',
'data (truncated)'
if not args.get('no_truncate') else ''))
# print revision count
if args.get('raw'):
print('%8s: %*s%*s %s' % (
'%04x' % 0,
lifetime_width, '',
w_width, '',
next(xxd(data[0:4]))))
# print tags
lower_, upper_ = 0, 0
wastrunk = False
j_ = 4
while j_ < (block_size if args.get('all') else off):
notes = []
j = j_
v, tag, w, size, d = fromtag(data[j_:])
if v != (popc(crc) & 1):
notes.append('v!=%x' % (popc(crc) & 1))
tag &= ~1
crc = crc32c(data[j_:j_+d], crc)
j_ += d
# find trunk
if not wastrunk and (tag & 0xc) != 0x4:
lower_, upper_ = 0, 0
wastrunk = not not tag & 0x8
# calculate id from alt weights
if tag & 0x8:
if tag & 0x4:
upper_ += w
else:
lower_ += w
elif (tag & 0xc) == 0x0:
weight_ = lower_+upper_+w
id = lower_+w-1
if not tag & 0x8:
if (tag & 0xf00f) != TAG_CRC:
crc = crc32c(data[j_:j_+size], crc)
# found a crc?
else:
crc_ = fromle32(data[j_:j_+4])
if crc != crc_:
notes.append('crc!=%08x' % crc)
j_ += size
# show human-readable tag representation
print('%s%08x:%s %*s%s%*s %-57s%s%s' % (
'\x1b[90m' if color and j >= off else '',
j,
'\x1b[m' if color and j >= off else '',
lifetime_width, lifetimerepr(j) if args.get('lifetimes') else '',
'\x1b[90m' if color and j >= off else '',
w_width, '' if (tag & 0xc) != 0x0
else '%d-%d' % (id-(w-1), id) if w > 1
else id,
'%-22s%s' % (
tagrepr(tag, w, size, j),
' %s' % next(xxd(
data[j+d:j+d+min(size, 8)], 8), '')
if not args.get('no_truncate')
and not tag & 0x8 else ''),
'\x1b[m' if color and j >= off else '',
' (%s)' % ', '.join(notes) if notes
else ' %s' % jumprepr(j)
if args.get('jumps')
else ''))
# show in-device representation, including some extra
# crc/parity info
if args.get('device'):
print('%s%8s %*s%*s %-47s %08x %x%s' % (
'\x1b[90m' if color and j >= off else '',
'',
lifetime_width, '',
w_width, '',
'%-22s%s' % (
'%04x %08x %07x' % (tag, w, size),
' %s' % ' '.join(
'%08x' % fromle32(
data[j+d+i*4:j+d+min(i*4+4,size)])
for i in range(min(m.ceil(size/4), 3)))[:23]
if not args.get('no_truncate')
and not tag & 0x8 else ''),
crc,
popc(crc) & 1,
'\x1b[m' if color and j >= off else ''))
# show on-disk encoding of tags
if args.get('raw'):
for o, line in enumerate(xxd(data[j:j+d])):
print('%s%8s: %*s%*s %s%s' % (
'\x1b[90m' if color and j >= off else '',
'%04x' % (j + o*16),
lifetime_width, '',
w_width, '',
line,
'\x1b[m' if color and j >= off else ''))
if args.get('raw') or args.get('no_truncate'):
if not tag & 0x8:
for o, line in enumerate(xxd(data[j+d:j+d+size])):
print('%s%8s: %*s%*s %s%s' % (
'\x1b[90m' if color and j >= off else '',
'%04x' % (j+d + o*16),
lifetime_width, '',
w_width, '',
line,
'\x1b[m' if color and j >= off else ''))
def show_tree(data, block_size, rev, trunk, weight, *,
color=False,
**args):
if not trunk:
return
# lookup a tag, returning also the search path for decoration
# purposes
def lookup(id, tag):
lower = -1
upper = weight
path = []
# descend down tree
j = trunk
while True:
_, alt, w, jump, d = fromtag(data[j:])
# found an alt?
if alt & 0x8:
# follow?
if ((id, tag & ~0xf) > (upper-w-1, alt & ~0xf)
if alt & 0x4
else ((id, tag & ~0xf) <= (lower+w, alt & ~0xf))):
lower += upper-lower-1-w if alt & 0x4 else 0
upper -= upper-lower-1-w if not alt & 0x4 else 0
j = j - jump
if args.get('tree'):
# figure out which color
if alt & 0x2:
_, nalt, _, _, _ = fromtag(data[j+jump+d:])
if nalt & 0x2:
path.append((j+jump, j, True, 'y'))
else:
path.append((j+jump, j, True, 'r'))
else:
path.append((j+jump, j, True, 'b'))
# stay on path
else:
lower += w if not alt & 0x4 else 0
upper -= w if alt & 0x4 else 0
j = j + d
if args.get('tree'):
# figure out which color
if alt & 0x2:
_, nalt, _, _, _ = fromtag(data[j:])
if nalt & 0x2:
path.append((j-d, j, False, 'y'))
else:
path.append((j-d, j, False, 'r'))
else:
path.append((j-d, j, False, 'b'))
# found tag
else:
id_ = upper-1
tag_ = alt
w_ = id_-lower
done = (id_, tag_) < (id, tag) or tag_ & 2
return done, id_, tag_, w_, j, d, jump, path
# precompute tree
tree_width = 0
if args.get('tree'):
trunks = co.defaultdict(lambda: (-1, 0))
alts = co.defaultdict(lambda: {})
id, tag = -1, 0
while True:
done, id, tag, w, j, d, size, path = lookup(id, tag+0x10)
# found end of tree?
if done:
break
# keep track of trunks/alts
trunks[j] = (id, tag)
for j_, j__, followed, c in path:
if followed:
alts[j_] |= {'f': j__, 'c': c}
else:
alts[j_] |= {'nf': j__, 'c': c}
# prune any alts with unreachable edges
pruned = {}
for j_, alt in alts.items():
if 'f' not in alt:
pruned[j_] = alt['nf']
elif 'nf' not in alt:
pruned[j_] = alt['f']
for j_ in pruned.keys():
del alts[j_]
for j_, alt in alts.items():
while alt['f'] in pruned:
alt['f'] = pruned[alt['f']]
while alt['nf'] in pruned:
alt['nf'] = pruned[alt['nf']]
# find the trunk and depth of each alt, assuming pruned alts
# didn't exist
def rec_trunk(j_):
if j_ not in alts:
return j_
else:
if 't' not in alts[j_]:
alts[j_]['t'] = rec_trunk(alts[j_]['nf'])
return alts[j_]['t']
for j_ in alts.keys():
rec_trunk(j_)
for j_, alt in alts.items():
if alt['f'] in alts:
alt['ft'] = alts[alt['f']]['t']
else:
alt['ft'] = alt['f']
def rec_depth(j_):
if j_ not in alts:
return 0
else:
if 'd' not in alts[j_]:
alts[j_]['d'] = max(
rec_depth(alts[j_]['f']),
rec_depth(alts[j_]['nf'])) + 1
return alts[j_]['d']
for j_ in alts.keys():
rec_depth(j_)
# oh hey this also gives us the max depth
tree_depth = max((alt['d'] for alt in alts.values()), default=0)
if tree_depth > 0:
tree_width = 2*tree_depth + 2
def treerepr(j):
if tree_depth == 0:
return ''
def c(s, c):
return '%s%s%s' % (
'\x1b[33m' if color and c == 'y'
else '\x1b[31m' if color and c == 'r'
else '\x1b[90m' if color
else '',
s,
'\x1b[m' if color else '')
trunk = []
def altrepr(j, x, was=None):
# note all non-trunk edges should be black
for alt in alts.values():
if alt['d'] == x and alt['t'] == j:
return '+-', alt['c'], alt['c']
for alt in alts.values():
if (alt['d'] == x
and alt['ft'] == j
and trunks[j] <= trunks[alt['t']]):
return '.-', 'b', 'b'
for alt in alts.values():
if (alt['d'] == x
and alt['ft'] == j
and trunks[j] >= trunks[alt['t']]):
return '\'-', 'b', 'b'
for alt in alts.values():
if (alt['d'] == x
and trunks[j] >= min(
trunks[alt['t']], trunks[alt['ft']])
and trunks[j] <= max(
trunks[alt['t']], trunks[alt['ft']])):
return '| ', 'b', was
if was:
return '--', was, was
return ' ', None, None
was = None
for x in reversed(range(1, tree_depth+1)):
t, c, was = altrepr(j, x, was)
trunk.append('%s%s%s%s' % (
'\x1b[33m' if color and c == 'y'
else '\x1b[31m' if color and c == 'r'
else '\x1b[90m' if color
else '',
t,
('>' if was else ' ')
if x == 1 else '',
'\x1b[m' if color else ''))
return ' %s' % ''.join(trunk)
# print header
w_width = 2*m.ceil(m.log10(max(1, weight)+1))+1
print('%-8s %*s%-*s %-22s %s' % (
'off',
tree_width, '',
w_width, 'ids',
'tag',
'data (truncated)'
if not args.get('no_truncate') else ''))
id, tag = -1, 0
while True:
done, id, tag, w, j, d, size, path = lookup(id, tag+0x10)
# found end of tree?
if done:
break
# show human-readable tag representation
print('%08x:%s %-57s' % (
j,
treerepr(j) if args.get('tree') else '',
'%*s %-22s%s' % (
w_width, '%d-%d' % (id-(w-1), id)
if w > 1 else id
if w > 0 else '',
tagrepr(tag, w, size, j),
' %s' % next(xxd(
data[j+d:j+d+min(size, 8)], 8), '')
if not args.get('no_truncate')
and not tag & 0x8 else '')))
# show in-device representation
if args.get('device'):
print('%8s %*s%*s %s' % (
'',
tree_width, '',
w_width, '',
'%-22s%s' % (
'%04x %08x %07x' % (tag, 0xffffffff & id, size),
' %s' % ' '.join(
'%08x' % fromle32(
data[j+d+i*4:j+d+min(i*4+4,size)])
for i in range(min(m.ceil(size/4), 3)))[:23]
if not args.get('no_truncate')
and not tag & 0x8 else '')))
# show on-disk encoding of tags
if args.get('raw'):
for o, line in enumerate(xxd(data[j:j+d])):
print('%8s: %*s%*s %s' % (
'%04x' % (j + o*16),
tree_width, '',
w_width, '',
line))
if args.get('raw') or args.get('no_truncate'):
if not tag & 0x8:
for o, line in enumerate(xxd(data[j+d:j+d+size])):
print('%8s: %*s%*s %s' % (
'%04x' % (j+d + o*16),
tree_width, '',
w_width, '',
line))
def main(disk, block1=0, block2=None, *,
block_size=None,
trunk=None,
color='auto',
**args):
# figure out what color should be
if color == 'auto':
color = sys.stdout.isatty()
elif color == 'always':
color = True
else:
color = False
with open(disk, 'rb') as f:
# if block_size is omitted, assume the block device is one big block
if block_size is None:
f.seek(0, os.SEEK_END)
block_size = f.tell()
# blocks may also encode trunks
blocks = [
block[0] if isinstance(block, tuple) else block
for block in [block1, block2]
if block is not None]
trunks = [
trunk if trunk is not None
else block[1] if isinstance(block, tuple)
else None
for block in [block1, block2]
if block is not None]
# read each block
datas = []
for block in blocks:
f.seek(block * block_size)
datas.append(f.read(block_size))
# first figure out which block as the most recent revision
def fetch(data, trunk):
rev = fromle32(data[0:4])
crc = 0
crc_ = crc32c(data[0:4])
off = 0
j_ = 4
trunk_ = 0
trunk__ = 0
weight = 0
lower_, upper_ = 0, 0
weight_ = 0
wastrunk = False
trunkoff = None
while j_ < len(data) and (not trunk or off <= trunk):
v, tag, w, size, d = fromtag(data[j_:])
if v != (popc(crc_) & 1):
break
crc_ = crc32c(data[j_:j_+d], crc_)
j_ += d
if not tag & 0x8 and j_ + size > len(data):
break
# take care of crcs
if not tag & 0x8:
if (tag & 0xf00f) != TAG_CRC:
crc_ = crc32c(data[j_:j_+size], crc_)
# found a crc?
else:
crc__ = fromle32(data[j_:j_+4])
if crc_ != crc__:
break
# commit what we have
off = trunkoff if trunkoff else j_ + size
crc = crc_
trunk_ = trunk__
weight = weight_
# evaluate trunks
if (tag & 0xc) != 0x4 and (
not trunk or trunk >= j_-d or wastrunk):
# new trunk?
if not wastrunk:
trunk__ = j_-d
lower_, upper_ = 0, 0
wastrunk = True
# keep track of weight
if tag & 0x8:
if tag & 0x4:
upper_ += w
else:
lower_ += w
else:
weight_ = lower_+upper_+w
wastrunk = False
# keep track of off for best matching trunk
if trunk and j_ + size > trunk:
trunkoff = j_ + size
if not tag & 0x8:
j_ += size
return rev, off, trunk_, weight
revs, offs, trunks_, weights = [], [], [], []
i = 0
for data, trunk in zip(datas, trunks):
rev, off, trunk_, weight = fetch(data, trunk)
revs.append(rev)
offs.append(off)
trunks_.append(trunk_)
weights.append(weight)
# compare with sequence arithmetic
if off and ((rev - revs[i]) & 0x80000000):
i = len(revs)-1
# print contents of the winning metadata block
block, data, rev, off, trunk, weight = (
blocks[i], datas[i], revs[i], offs[i], trunks_[i], weights[i])
print('rbyd 0x%x.%x, rev %d, size %d, weight %d%s' % (
block, trunk, rev, off, weight,
' (was 0x%x.%x, %d, %d, %d)' % (
blocks[~i], trunks_[~i], revs[~i], offs[~i], weights[~i])
if len(blocks) > 1 else ''))
if args.get('log'):
show_log(data, block_size, rev, off, weight,
color=color,
**args)
else:
show_tree(data, block_size, rev, trunk, weight,
color=color,
**args)
if args.get('error_on_corrupt') and off == 0:
sys.exit(2)
if __name__ == "__main__":
import argparse
import sys
parser = argparse.ArgumentParser(
description="Debug rbyd metadata.",
allow_abbrev=False)
parser.add_argument(
'disk',
help="File containing the block device.")
parser.add_argument(
'block1',
nargs='?',
type=rbydaddr,
help="Block address of the first metadata block.")
parser.add_argument(
'block2',
nargs='?',
type=rbydaddr,
help="Block address of the second metadata block.")
parser.add_argument(
'-B', '--block-size',
type=lambda x: int(x, 0),
help="Block size in bytes.")
parser.add_argument(
'--trunk',
type=lambda x: int(x, 0),
help="Use this offset as the trunk of the tree.")
parser.add_argument(
'--color',
choices=['never', 'always', 'auto'],
default='auto',
help="When to use terminal colors. Defaults to 'auto'.")
parser.add_argument(
'-a', '--all',
action='store_true',
help="Don't stop parsing on bad commits.")
parser.add_argument(
'-l', '--log',
action='store_true',
help="Show the raw tags as they appear in the log.")
parser.add_argument(
'-r', '--raw',
action='store_true',
help="Show the raw data including tag encodings.")
parser.add_argument(
'-x', '--device',
action='store_true',
help="Show the device-side representation of tags.")
parser.add_argument(
'-T', '--no-truncate',
action='store_true',
help="Don't truncate, show the full contents.")
parser.add_argument(
'-t', '--tree',
action='store_true',
help="Show the rbyd tree.")
parser.add_argument(
'-j', '--jumps',
action='store_true',
help="Show alt pointer jumps in the margin.")
parser.add_argument(
'-g', '--lifetimes',
action='store_true',
help="Show inserts/deletes of ids in the margin.")
parser.add_argument(
'-e', '--error-on-corrupt',
action='store_true',
help="Error if no valid commit is found.")
sys.exit(main(**{k: v
for k, v in vars(parser.parse_intermixed_args()).items()
if v is not None}))