database.py 文件源码

def prevreg(cls, ea, reg, *regs, **modifiers):
        regs = (reg,) + regs
        count = modifiers.get('count', 1)
        args = ', '.join(["{:x}".format(ea)] + __builtin__.map("\"{:s}\"".format, regs) + __builtin__.map(utils.unbox("{:s}={!r}".format), modifiers.items()))

        # generate each helper using the regmatch class
        iterops = interface.regmatch.modifier(**modifiers)
        uses_register = interface.regmatch.use(regs)

        # if within a function, then sure we're within the chunk's bounds.
        if function.within(ea):
            (start, _) = function.chunk(ea)
            fwithin = functools.partial(operator.le, start)

        # otherwise ensure that we're not in the function and we're a code type.
        else:
            fwithin = utils.compose(utils.fap(utils.compose(function.within, operator.not_), type.is_code), all)

            start = cls.walk(ea, cls.prev, fwithin)
            start = top() if start == idaapi.BADADDR else start

        # define a function for cls.walk to continue looping while
        F = lambda ea: fwithin(ea) and not any(uses_register(ea, opnum) for opnum in iterops(ea))

        # skip the current address
        prevea = cls.prev(ea)
        if prevea is None:
            # FIXME: include registers in message
            logging.fatal("{:s}.prevreg({:s}, ...) : Unable to start walking from previous address. : {:x}".format('.'.join((__name__, cls.__name__)), args, ea))
            return ea

        # now walk while none of our registers match
        res = cls.walk(prevea, cls.prev, F)
        if res == idaapi.BADADDR or (cls == address and res < start):
            # FIXME: include registers in message
            raise ValueError("{:s}.prevreg({:s}, ...) : Unable to find register{:s} within chunk. {:x}:{:x} : {:x}".format('.'.join((__name__, cls.__name__)), args, ('s','')[len(regs)>1], start, ea, res))

        # recurse if the user specified it
        modifiers['count'] = count - 1
        return cls.prevreg( cls.prev(res), *regs, **modifiers) if count > 1 else res