Re: [Qemu-devel] [PATCH v4 8/8] BitmapLog: python script for extracting bitmap from a binary file

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Sanidhya Kashyap (sanidhya.iiith@gmail.com) wrote:
> Signed-off-by: Sanidhya Kashyap <sanidhya.iiith@gmail.com>

I'm not really a python-person, but one observation:

> +def get_string(value, length):
> +	name = struct.unpack('<'+str(length)+'s', value)[0]
> +	for i in range(len(name)):
> +		if name[i] == '\x00':
> +			return name[:i]

Would it have been easier for you to format the strings in the stream
the same way the migration does it; i.e. a length byte followed by the text
of the string?

Dave

> +
> +def dump_ram_block_info(infile):
> +	total_blocks = get_integer(infile.read(int_bytes))
> +	for i in range(total_blocks):
> +		block_name = get_string(infile.read(string_bytes), string_bytes)
> +		block_offset = get_unsigned_long_integer(infile.read(long_bytes))
> +		block_length = get_unsigned_long_integer(infile.read(long_bytes))
> +		block_list.append(dict(name=block_name, offset=block_offset, length=block_length))
> +	print block_list
> +
> +def dump_bitmap(infile, bitmap_length):
> +	marker = 'M'
> +	count = 0
> +	value = ' '
> +	while True:
> +		if len(value) == 0  or marker != 'M':
> +			print len(complete_bitmap_list)
> +			print "issue with the dump"
> +			return
> +		bitmap_list = []
> +		bitmap_raw_value = infile.read(long_bytes * bitmap_length)
> +		if not bitmap_raw_value:
> +			print len(bitmap_raw_value)
> +			break
> +		count+=1
> +		for i in range(bitmap_length):
> +			mark = i * long_bytes
> +			bitmap_list.append(hex(get_unsigned_long_integer(bitmap_raw_value[mark:mark+long_bytes])))
> +		complete_bitmap_list.append(bitmap_list)
> +		value = infile.read(1)
> +		marker = get_char(value)
> +	print complete_bitmap_list
> +
> +def main():
> +	extracter = argparse.ArgumentParser(description='Extract dirty bitmap from binary file.')
> +	extracter.add_argument('infile', help='Input file to extract the bitmap')
> +	args = extracter.parse_args()
> +	print 'The filename is {}'.format(args.infile)
> +
> +	infile = open(format(args.infile), 'rb')
> +
> +	ram_bitmap_pages = get_long_integer(infile.read(long_bytes))
> +	print ram_bitmap_pages
> +	dump_ram_block_info(infile)
> +	bitmap_length = ram_bitmap_pages / (long_bytes * byte_size)
> +	if ram_bitmap_pages % (long_bytes * byte_size) != 0:
> +		bitmap_length += 1
> +	print bitmap_length
> +
> +	dump_bitmap(infile, bitmap_length);
> +
> +	infile.close()
> +
> +if __name__ == '__main__':
> +	main()
> -- 
> 1.9.3
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK