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#! /usr/bin/env python3
# Copyright (C) 2012 The Android Open Source Project
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import csv
import getopt
import hashlib
import posixpath
import signal
import struct
import sys
def usage(argv0):
print("""
Usage: %s [-v] [-s] [-c <filename>] sparse_image_file ...
-v verbose output
-s show sha1sum of data blocks
-c <filename> save .csv file of blocks
""" % (argv0))
sys.exit(2)
def main():
signal.signal(signal.SIGPIPE, signal.SIG_DFL)
me = posixpath.basename(sys.argv[0])
# Parse the command line
verbose = 0 # -v
showhash = 0 # -s
csvfilename = None # -c
try:
opts, args = getopt.getopt(sys.argv[1:],
"vsc:",
["verbose", "showhash", "csvfile"])
except getopt.GetoptError as e:
print(e)
usage(me)
for o, a in opts:
if o in ("-v", "--verbose"):
verbose += 1
elif o in ("-s", "--showhash"):
showhash = True
elif o in ("-c", "--csvfile"):
csvfilename = a
else:
print("Unrecognized option \"%s\"" % (o))
usage(me)
if not args:
print("No sparse_image_file specified")
usage(me)
if csvfilename:
csvfile = open(csvfilename, "wb")
csvwriter = csv.writer(csvfile)
output = verbose or csvfilename or showhash
for path in args:
FH = open(path, "rb")
header_bin = FH.read(28)
header = struct.unpack("<I4H4I", header_bin)
magic = header[0]
major_version = header[1]
minor_version = header[2]
file_hdr_sz = header[3]
chunk_hdr_sz = header[4]
blk_sz = header[5]
total_blks = header[6]
total_chunks = header[7]
image_checksum = header[8]
if magic != 0xED26FF3A:
print("%s: %s: Magic should be 0xED26FF3A but is 0x%08X"
% (me, path, magic))
continue
if major_version != 1 or minor_version != 0:
print("%s: %s: I only know about version 1.0, but this is version %u.%u"
% (me, path, major_version, minor_version))
continue
if file_hdr_sz != 28:
print("%s: %s: The file header size was expected to be 28, but is %u."
% (me, path, file_hdr_sz))
continue
if chunk_hdr_sz != 12:
print("%s: %s: The chunk header size was expected to be 12, but is %u."
% (me, path, chunk_hdr_sz))
continue
print("%s: Total of %u %u-byte output blocks in %u input chunks."
% (path, total_blks, blk_sz, total_chunks))
if image_checksum != 0:
print("checksum=0x%08X" % (image_checksum))
if not output:
continue
if verbose > 0:
print(" input_bytes output_blocks")
print("chunk offset number offset number")
if csvfilename:
csvwriter.writerow(["chunk", "input offset", "input bytes",
"output offset", "output blocks", "type", "hash"])
offset = 0
for i in range(1, total_chunks + 1):
header_bin = FH.read(12)
header = struct.unpack("<2H2I", header_bin)
chunk_type = header[0]
chunk_sz = header[2]
total_sz = header[3]
data_sz = total_sz - 12
curhash = ""
curtype = ""
curpos = FH.tell()
if verbose > 0:
print("%4u %10u %10u %7u %7u" % (i, curpos, data_sz, offset, chunk_sz),
end=" ")
if chunk_type == 0xCAC1:
if data_sz != (chunk_sz * blk_sz):
print("Raw chunk input size (%u) does not match output size (%u)"
% (data_sz, chunk_sz * blk_sz))
break
else:
curtype = "Raw data"
data = FH.read(data_sz)
if showhash:
h = hashlib.sha1()
h.update(data)
curhash = h.hexdigest()
elif chunk_type == 0xCAC2:
if data_sz != 4:
print("Fill chunk should have 4 bytes of fill, but this has %u"
% (data_sz))
break
else:
fill_bin = FH.read(4)
fill = struct.unpack("<I", fill_bin)
curtype = format("Fill with 0x%08X" % (fill))
if showhash:
h = hashlib.sha1()
data = fill_bin * (blk_sz // 4);
for block in range(chunk_sz):
h.update(data)
curhash = h.hexdigest()
elif chunk_type == 0xCAC3:
if data_sz != 0:
print("Don't care chunk input size is non-zero (%u)" % (data_sz))
break
else:
curtype = "Don't care"
elif chunk_type == 0xCAC4:
if data_sz != 4:
print("CRC32 chunk should have 4 bytes of CRC, but this has %u"
% (data_sz))
break
else:
crc_bin = FH.read(4)
crc = struct.unpack("<I", crc_bin)
curtype = format("Unverified CRC32 0x%08X" % (crc))
else:
print("Unknown chunk type 0x%04X" % (chunk_type))
break
if verbose > 0:
print("%-18s" % (curtype), end=" ")
if verbose > 1:
header = struct.unpack("<12B", header_bin)
print(" (%02X%02X %02X%02X %02X%02X%02X%02X %02X%02X%02X%02X)"
% (header[0], header[1], header[2], header[3],
header[4], header[5], header[6], header[7],
header[8], header[9], header[10], header[11]), end=" ")
print(curhash)
if csvfilename:
csvwriter.writerow([i, curpos, data_sz, offset, chunk_sz, curtype,
curhash])
offset += chunk_sz
if verbose > 0:
print(" %10u %7u End" % (FH.tell(), offset))
if total_blks != offset:
print("The header said we should have %u output blocks, but we saw %u"
% (total_blks, offset))
junk_len = len(FH.read())
if junk_len:
print("There were %u bytes of extra data at the end of the file."
% (junk_len))
if csvfilename:
csvfile.close()
sys.exit(0)
if __name__ == "__main__":
main()
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