def METHOD_NAME(vm, start_pos=0, start_str=START_PATTERN, end_str=END_PATTERN):
    """
    Get the specified content of SLOF by reading the serial log.
    :param vm: VM object
    :param start_pos: start position which start to read
    :type start_pos: int
    :param start_str: start string pattern
    :type start_str: int
    :param end_str: end string pattern
    :type end_str: str
    :return: content list and next position of the end of the content if found
             the the whole SLOF contents, otherwise return None and the
             position of start string.
    :rtype: tuple(list, int)
    """
    content = []
    start_str_pos = 0
    with open(vm.serial_console_log) as fd:
        for pos, line in enumerate(fd):
            if pos >= start_pos:
                if re.search(start_str, line):
                    start_str_pos = pos
                    content.append(line)
                elif content:
                    content.append(line)
                    if re.search(end_str, line):
                        return content, pos + 1
            else:
                start_str_pos = pos + 1
        else:
            return None, start_str_pos