forked from Imagelibrary/littlefs
ad00ca79e2
- We need to actually write the perturb bit - It helps to encode the crc's leb128 length field correctly
226 lines
6.8 KiB
Python
Executable File
226 lines
6.8 KiB
Python
Executable File
#!/usr/bin/env python3
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import itertools as it
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import math as m
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import struct
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def crc32c(data, crc=0):
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crc ^= 0xffffffff
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for b in data:
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crc ^= b
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for j in range(8):
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crc = (crc >> 1) ^ ((crc & 1) * 0x82f63b78)
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return 0xffffffff ^ crc
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def fromleb128(data):
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word = 0
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for i, b in enumerate(data):
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word |= ((b & 0x7f) << 7*i)
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word &= 0xffffffff
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if not b & 0x80:
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return word, i+1
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return word, len(data)
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def fromtag(data):
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tag, delta1 = fromleb128(data)
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size, delta2 = fromleb128(data[delta1:])
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return tag & 1, tag >> 1, size, delta1+delta2
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def popc(x):
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return bin(x).count('1')
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def xxd(data, width=16, crc=False):
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for i in range(0, len(data), width):
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yield '%-*s %-*s' % (
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3*width,
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' '.join('%02x' % b for b in data[i:i+width]),
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width,
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''.join(
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b if b >= ' ' and b <= '~' else '.'
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for b in map(chr, data[i:i+width])))
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def tagrepr(tag, size, off=None):
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type1 = tag & 0x7f
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type2 = (tag >> 7) & 0xff
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id = (tag >> 15) & 0xffff
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if type1 & 1:
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return 'alt %s %s x%x %s' % (
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'r' if type1 & 4 else 'b',
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'gt' if type1 & 2 else 'lt',
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tag >> 3,
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'x%x' % (0xffffffff & (off-size))
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if off is not None
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else '-%d' % off)
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elif type1 == 0x40:
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return 'create x%02x id%d %d' % (type2, id, size)
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elif type1 == 0x48:
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return 'delete x%02x id%d %d' % (type2, id, size)
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elif type1 == 0x50:
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return 'struct x%02x id%d %d' % (type2, id, size)
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elif type1 == 0x60:
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return 'uattr x%02x id%d %d' % (type2, id, size)
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elif type1 == 0x08:
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if type2 == 0:
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return 'tail %d' % size
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else:
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return 'tail x%02x %d' % (type2, size)
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elif type1 == 0x10:
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return 'gstate x%02x %d' % (type2, size)
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elif type1 == 0x02 or type1 == 0x0a:
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if type2 == 0:
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return 'crc%x %d' % (type1 >> 3, size)
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else:
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return 'crc%x x%02x %d' % (type1 >> 3, type2, size)
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elif type1 == 0x12:
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if type2 == 0:
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return 'fcrc %d' % (size)
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else:
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return 'fcrc x%02x %d' % (type2, size)
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else:
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return 'x%02x x%02x id%d %d' % (type1, type2, id, size)
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def main(disk, block_size, block1, block2=None, **args):
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# read each block
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blocks = [block for block in [block1, block2] if block is not None]
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with open(disk, 'rb') as f:
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datas = []
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for block in blocks:
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f.seek(block * block_size)
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datas.append(f.read(block_size))
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# first figure out which block as the most recent revision
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def fetch(data):
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rev, = struct.unpack('<I', data[0:4])
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crc = crc32c(data[0:4])
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off = 0
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j = 4
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while j < block_size:
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v, tag, size, delta = fromtag(data[j:])
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if v != popc(crc) & 1:
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break
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crc = crc32c(data[j:j+delta], crc)
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j += delta
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if not tag & 0x1:
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if (tag & 0x37) != 0x2:
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crc = crc32c(data[j:j+size], crc)
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# found a crc?
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else:
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crc_, = struct.unpack('<I', data[j:j+4])
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if crc != crc_:
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break
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# commit what we have
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off = j + size
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j += size
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return rev, off
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revs, offs = [], []
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i = 0
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for block, data in zip(blocks, datas):
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rev, off = fetch(data)
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revs.append(rev)
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offs.append(off)
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# compare with sequence arithmetic
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if off and ((rev - revs[i]) & 0x80000000):
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i = len(revs)-1
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# print contents of the winning metadata block
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block, data, rev, off = blocks[i], datas[i], revs[i], offs[i]
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print('mdir 0x%x, rev %d, size %d (was 0x%x, %d, %d)' % (
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block, rev, off,
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blocks[len(blocks)-1-i],
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revs[len(revs)-1-i],
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offs[len(offs)-1-i]))
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print('%-8s %-22s %s' % (
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'off', 'tag',
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'data (truncated)'
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if not args.get('no_truncate') else ''))
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# print revision count
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crc = crc32c(data[0:4])
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if args.get('raw'):
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print('%08x: %s' % (0, next(xxd(data[0:4]))))
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# print tags
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j = 4
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while j < (block_size if args.get('all') else off):
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notes = []
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v, tag, size, delta = fromtag(data[j:])
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if v != popc(crc) & 1:
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notes.append('v!=%x' % (popc(crc) & 1))
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crc = crc32c(data[j:j+delta], crc)
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j += delta
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if not tag & 0x1:
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if (tag & 0x37) != 0x2:
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crc = crc32c(data[j:j+size], crc)
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# found a crc?
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else:
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crc_, = struct.unpack('<I', data[j:j+4])
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if crc != crc_:
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notes.append('crc!=%08x' % crc)
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j += size
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print('%08x: %-57s%s' % (
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j-delta-size,
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'%-22s%s' % (
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tagrepr(tag, size, j),
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' %s' % next(xxd(data[j-size:j-size+min(size, 8)], 8), '')
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if not tag & 1 and not args.get('no_truncate') else ''),
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' (%s)' % ', '.join(notes)
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if notes else ''))
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if args.get('raw'):
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for o, line in enumerate(xxd(data[j-delta-size:j-size])):
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print('%8s: %s' % ('%04x' % (j-delta-size + o*16), line))
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if not tag & 0x1:
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if args.get('raw') or args.get('no_truncate'):
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for o, line in enumerate(xxd(data[j-size:j])):
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print('%8s: %s' % ('%04x' % (j-size + o*16), line))
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if __name__ == "__main__":
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import argparse
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import sys
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parser = argparse.ArgumentParser(
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description="Debug rbyd metadata.",
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allow_abbrev=False)
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parser.add_argument(
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'disk',
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help="File containing the block device.")
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parser.add_argument(
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'block_size',
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type=lambda x: int(x, 0),
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help="Block size in bytes.")
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parser.add_argument(
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'block1',
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type=lambda x: int(x, 0),
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help="Block address of the first metadata block.")
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parser.add_argument(
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'block2',
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nargs='?',
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type=lambda x: int(x, 0),
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help="Block address of the second metadata block.")
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parser.add_argument(
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'-a', '--all',
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action='store_true',
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help="Don't stop parsing on bad commits.")
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parser.add_argument(
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'-R', '--raw',
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action='store_true',
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help="Show the raw data including tag encodings.")
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parser.add_argument(
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'-T', '--no-truncate',
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action='store_true',
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help="Don't truncate, show the full contents.")
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sys.exit(main(**{k: v
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for k, v in vars(parser.parse_intermixed_args()).items()
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if v is not None}))
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