cbfs.py 文件源码

def recognizes(cls, file):
        size = os.stat(file.path).st_size
        if size < CBFS_HEADER_SIZE or size > CBFS_MAXIMUM_FILE_SIZE:
            return False
        with open(file.path, 'rb') as f:
            # pick at the latest byte as it should contain the relative offset of the header
            f.seek(-4, io.SEEK_END)
            # <pgeorgi> given the hardware we support so far, it looks like
            #           that field is now bound to be little endian
            #   -- #coreboot, 2015-10-14
            rel_offset = struct.unpack('<i', f.read(4))[0]
            if rel_offset < 0 and -rel_offset > CBFS_HEADER_SIZE and -rel_offset < size:
                f.seek(rel_offset, io.SEEK_END)
                logger.debug('looking for header at offset: %x', f.tell())
                if is_header_valid(f.read(CBFS_HEADER_SIZE), size):
                    return True
            elif not file.name.endswith('.rom'):
                return False
            else:
                logger.debug('CBFS relative offset seems wrong, scanning whole image')
            f.seek(0, io.SEEK_SET)
            offset = 0
            buf = f.read(CBFS_HEADER_SIZE)
            while len(buf) >= CBFS_HEADER_SIZE:
                if is_header_valid(buf, size, offset):
                    return True
                if len(buf) - offset <= CBFS_HEADER_SIZE:
                    buf = f.read(32768)
                    offset = 0
                else:
                    offset += 1
            return False