dash/contrib/linearize/linearize-data.py
Wladimir J. van der Laan bba59cabc3
Merge #16802: scripts: In linearize, search for next position of magic bytes rather than fail
3284e6c09a84e9557ec72723ad636053d3ef7122 scripts: search for next position of magic bytes rather than fail (Tim Akinbo)

Pull request description:

  When using the `linearize-data.py` contrib script to export block data, there are edge cases where the script fails with an `Invalid magic: 00000000` error. This error occurs due to the presence of padding bytes that occasionally appears between consecutive blocks in the block data file.

  There's an ongoing conversation about this in #14986. sipa also admitted that it is a bug in #5028. Fortunately, this is not an issue in bitcoin core as it handles this type of situation gracefully and so no fix in bitcoin core is required.

  This PR is an improvement on how the script handles these "invalid magic bytes". Rather than failing, this patch allows the script to search for the next occurrence of the magic bytes and then starts reading the block from there.

ACKs for top commit:
  laanwj:
    ACK 3284e6c09a84e9557ec72723ad636053d3ef7122

Tree-SHA512: 18067ae0b4b62e822dfc558a86439ad6acaf939b98479e38e8e4248536574643b26eb48e96ec7139375c88b42cbe7705a64deb13a3c239e16025a6aad3d69bfa
2021-09-15 13:54:38 -04:00

353 lines
13 KiB
Python
Executable File

#!/usr/bin/env python3
#
# linearize-data.py: Construct a linear, no-fork version of the chain.
#
# Copyright (c) 2013-2014 The Bitcoin Core developers
# Distributed under the MIT software license, see the accompanying
# file COPYING or http://www.opensource.org/licenses/mit-license.php.
#
import struct
import re
import os
import os.path
import sys
import dash_hash
import datetime
import time
import glob
from collections import namedtuple
from binascii import unhexlify
settings = {}
def hex_switchEndian(s):
""" Switches the endianness of a hex string (in pairs of hex chars) """
pairList = [s[i:i+2].encode() for i in range(0, len(s), 2)]
return b''.join(pairList[::-1]).decode()
def uint32(x):
return x & 0xffffffff
def bytereverse(x):
return uint32(( ((x) << 24) | (((x) << 8) & 0x00ff0000) |
(((x) >> 8) & 0x0000ff00) | ((x) >> 24) ))
def bufreverse(in_buf):
out_words = []
for i in range(0, len(in_buf), 4):
word = struct.unpack('@I', in_buf[i:i+4])[0]
out_words.append(struct.pack('@I', bytereverse(word)))
return b''.join(out_words)
def wordreverse(in_buf):
out_words = []
for i in range(0, len(in_buf), 4):
out_words.append(in_buf[i:i+4])
out_words.reverse()
return b''.join(out_words)
def calc_hdr_hash(blk_hdr):
#hash1 = hashlib.sha256()
#hash1.update(blk_hdr)
#hash1_o = hash1.digest()
#hash2 = hashlib.sha256()
#hash2.update(hash1_o)
#hash2_o = hash2.digest()
#return hash2_o
pow_hash = dash_hash.getPoWHash(blk_hdr)
return pow_hash
def calc_hash_str(blk_hdr):
hash = calc_hdr_hash(blk_hdr)
hash = bufreverse(hash)
hash = wordreverse(hash)
hash_str = hash.hex()
return hash_str
def get_blk_dt(blk_hdr):
members = struct.unpack("<I", blk_hdr[68:68+4])
nTime = members[0]
dt = datetime.datetime.fromtimestamp(nTime)
dt_ym = datetime.datetime(dt.year, dt.month, 1)
return (dt_ym, nTime)
# When getting the list of block hashes, undo any byte reversals.
def get_block_hashes(settings):
blkindex = []
f = open(settings['hashlist'], "r", encoding="utf8")
for line in f:
line = line.rstrip()
if settings['rev_hash_bytes'] == 'true':
line = hex_switchEndian(line)
blkindex.append(line)
print("Read " + str(len(blkindex)) + " hashes")
return blkindex
# The block map shouldn't give or receive byte-reversed hashes.
def mkblockmap(blkindex):
blkmap = {}
for height,hash in enumerate(blkindex):
blkmap[hash] = height
return blkmap
# This gets the first block file ID that exists from the input block
# file directory.
def getFirstBlockFileId(block_dir_path):
# First, this sets up a pattern to search for block files, for
# example 'blkNNNNN.dat'.
blkFilePattern = os.path.join(block_dir_path, "blk[0-9][0-9][0-9][0-9][0-9].dat")
# This search is done with glob
blkFnList = glob.glob(blkFilePattern)
if len(blkFnList) == 0:
print("blocks not pruned - starting at 0")
return 0
# We then get the lexicographic minimum, which should be the first
# block file name.
firstBlkFilePath = min(blkFnList)
firstBlkFn = os.path.basename(firstBlkFilePath)
# now, the string should be ['b','l','k','N','N','N','N','N','.','d','a','t']
# So get the ID by choosing: 3 4 5 6 7
# The ID is not necessarily 0 if this is a pruned node.
blkId = int(firstBlkFn[3:8])
return blkId
# Block header and extent on disk
BlockExtent = namedtuple('BlockExtent', ['fn', 'offset', 'inhdr', 'blkhdr', 'size'])
class BlockDataCopier:
def __init__(self, settings, blkindex, blkmap):
self.settings = settings
self.blkindex = blkindex
self.blkmap = blkmap
# Get first occurring block file id - for pruned nodes this
# will not necessarily be 0
self.inFn = getFirstBlockFileId(self.settings['input'])
self.inF = None
self.outFn = 0
self.outsz = 0
self.outF = None
self.outFname = None
self.blkCountIn = 0
self.blkCountOut = 0
self.lastDate = datetime.datetime(2000, 1, 1)
self.highTS = 1408893517 - 315360000
self.timestampSplit = False
self.fileOutput = True
self.setFileTime = False
self.maxOutSz = settings['max_out_sz']
if 'output' in settings:
self.fileOutput = False
if settings['file_timestamp'] != 0:
self.setFileTime = True
if settings['split_timestamp'] != 0:
self.timestampSplit = True
# Extents and cache for out-of-order blocks
self.blockExtents = {}
self.outOfOrderData = {}
self.outOfOrderSize = 0 # running total size for items in outOfOrderData
def writeBlock(self, inhdr, blk_hdr, rawblock):
blockSizeOnDisk = len(inhdr) + len(blk_hdr) + len(rawblock)
if not self.fileOutput and ((self.outsz + blockSizeOnDisk) > self.maxOutSz):
self.outF.close()
if self.setFileTime:
os.utime(self.outFname, (int(time.time()), self.highTS))
self.outF = None
self.outFname = None
self.outFn = self.outFn + 1
self.outsz = 0
(blkDate, blkTS) = get_blk_dt(blk_hdr)
if self.timestampSplit and (blkDate > self.lastDate):
print("New month " + blkDate.strftime("%Y-%m") + " @ " + self.hash_str)
self.lastDate = blkDate
if self.outF:
self.outF.close()
if self.setFileTime:
os.utime(self.outFname, (int(time.time()), self.highTS))
self.outF = None
self.outFname = None
self.outFn = self.outFn + 1
self.outsz = 0
if not self.outF:
if self.fileOutput:
self.outFname = self.settings['output_file']
else:
self.outFname = os.path.join(self.settings['output'], "blk%05d.dat" % self.outFn)
print("Output file " + self.outFname)
self.outF = open(self.outFname, "wb")
self.outF.write(inhdr)
self.outF.write(blk_hdr)
self.outF.write(rawblock)
self.outsz = self.outsz + len(inhdr) + len(blk_hdr) + len(rawblock)
self.blkCountOut = self.blkCountOut + 1
if blkTS > self.highTS:
self.highTS = blkTS
if (self.blkCountOut % 1000) == 0:
print('%i blocks scanned, %i blocks written (of %i, %.1f%% complete)' %
(self.blkCountIn, self.blkCountOut, len(self.blkindex), 100.0 * self.blkCountOut / len(self.blkindex)))
def inFileName(self, fn):
return os.path.join(self.settings['input'], "blk%05d.dat" % fn)
def fetchBlock(self, extent):
'''Fetch block contents from disk given extents'''
with open(self.inFileName(extent.fn), "rb") as f:
f.seek(extent.offset)
return f.read(extent.size)
def copyOneBlock(self):
'''Find the next block to be written in the input, and copy it to the output.'''
extent = self.blockExtents.pop(self.blkCountOut)
if self.blkCountOut in self.outOfOrderData:
# If the data is cached, use it from memory and remove from the cache
rawblock = self.outOfOrderData.pop(self.blkCountOut)
self.outOfOrderSize -= len(rawblock)
else: # Otherwise look up data on disk
rawblock = self.fetchBlock(extent)
self.writeBlock(extent.inhdr, extent.blkhdr, rawblock)
def run(self):
while self.blkCountOut < len(self.blkindex):
if not self.inF:
fname = self.inFileName(self.inFn)
print("Input file " + fname)
try:
self.inF = open(fname, "rb")
except IOError:
print("Premature end of block data")
return
inhdr = self.inF.read(8)
if (not inhdr or (inhdr[0] == "\0")):
self.inF.close()
self.inF = None
self.inFn = self.inFn + 1
continue
inMagic = inhdr[:4]
if (inMagic != self.settings['netmagic']):
# Seek backwards 7 bytes (skipping the first byte in the previous search)
# and continue searching from the new position if the magic bytes are not
# found.
self.inF.seek(-7, os.SEEK_CUR)
continue
inLenLE = inhdr[4:]
su = struct.unpack("<I", inLenLE)
inLen = su[0] - 80 # length without header
blk_hdr = self.inF.read(80)
inExtent = BlockExtent(self.inFn, self.inF.tell(), inhdr, blk_hdr, inLen)
self.hash_str = calc_hash_str(blk_hdr)
if not self.hash_str in blkmap:
# Because blocks can be written to files out-of-order as of 0.10, the script
# may encounter blocks it doesn't know about. Treat as debug output.
if settings['debug_output'] == 'true':
print("Skipping unknown block " + self.hash_str)
self.inF.seek(inLen, os.SEEK_CUR)
continue
blkHeight = self.blkmap[self.hash_str]
self.blkCountIn += 1
if self.blkCountOut == blkHeight:
# If in-order block, just copy
rawblock = self.inF.read(inLen)
self.writeBlock(inhdr, blk_hdr, rawblock)
# See if we can catch up to prior out-of-order blocks
while self.blkCountOut in self.blockExtents:
self.copyOneBlock()
else: # If out-of-order, skip over block data for now
self.blockExtents[blkHeight] = inExtent
if self.outOfOrderSize < self.settings['out_of_order_cache_sz']:
# If there is space in the cache, read the data
# Reading the data in file sequence instead of seeking and fetching it later is preferred,
# but we don't want to fill up memory
self.outOfOrderData[blkHeight] = self.inF.read(inLen)
self.outOfOrderSize += inLen
else: # If no space in cache, seek forward
self.inF.seek(inLen, os.SEEK_CUR)
print("Done (%i blocks written)" % (self.blkCountOut))
if __name__ == '__main__':
if len(sys.argv) != 2:
print("Usage: linearize-data.py CONFIG-FILE")
sys.exit(1)
f = open(sys.argv[1], encoding="utf8")
for line in f:
# skip comment lines
m = re.search('^\s*#', line)
if m:
continue
# parse key=value lines
m = re.search('^(\w+)\s*=\s*(\S.*)$', line)
if m is None:
continue
settings[m.group(1)] = m.group(2)
f.close()
# Force hash byte format setting to be lowercase to make comparisons easier.
# Also place upfront in case any settings need to know about it.
if 'rev_hash_bytes' not in settings:
settings['rev_hash_bytes'] = 'false'
settings['rev_hash_bytes'] = settings['rev_hash_bytes'].lower()
if 'netmagic' not in settings:
settings['netmagic'] = 'bf0c6bbd'
if 'genesis' not in settings:
settings['genesis'] = '00000ffd590b1485b3caadc19b22e6379c733355108f107a430458cdf3407ab6'
if 'input' not in settings:
settings['input'] = 'input'
if 'hashlist' not in settings:
settings['hashlist'] = 'hashlist.txt'
if 'file_timestamp' not in settings:
settings['file_timestamp'] = 0
if 'split_timestamp' not in settings:
settings['split_timestamp'] = 0
if 'max_out_sz' not in settings:
settings['max_out_sz'] = 1000 * 1000 * 1000
if 'out_of_order_cache_sz' not in settings:
settings['out_of_order_cache_sz'] = 100 * 1000 * 1000
if 'debug_output' not in settings:
settings['debug_output'] = 'false'
settings['max_out_sz'] = int(settings['max_out_sz'])
settings['split_timestamp'] = int(settings['split_timestamp'])
settings['file_timestamp'] = int(settings['file_timestamp'])
settings['netmagic'] = unhexlify(settings['netmagic'].encode('utf-8'))
settings['out_of_order_cache_sz'] = int(settings['out_of_order_cache_sz'])
settings['debug_output'] = settings['debug_output'].lower()
if 'output_file' not in settings and 'output' not in settings:
print("Missing output file / directory")
sys.exit(1)
blkindex = get_block_hashes(settings)
blkmap = mkblockmap(blkindex)
# Block hash map won't be byte-reversed. Neither should the genesis hash.
if not settings['genesis'] in blkmap:
print("Genesis block not found in hashlist")
else:
BlockDataCopier(settings, blkindex, blkmap).run()