From: budden
Subject: bug in a cffi? (crossposting from cffi-devel)
Date: Sat, 10 Jan 2009 19:28:24 +0000
Message-ID: <0093156c-b563-495d-b41c-349d5c614ad8@s9g2000prg.googlegroups.com>

Hi!
  I know that posting to devel-lists often fails, so I'm crossposting
it here.
  It looks like lisp-string-to-foreign might overflow buffer if
offset>0.

(defun lisp-string-to-foreign (string buffer bufsize &key (start 0)
end offset
                               (encoding *default-foreign-encoding*))
  (check-type string string)
  (when offset
     ; here should also be (setq buffer-size (- buffer-size
offset)) ???
    (setq buffer (inc-pointer buffer offset)))
  (with-checked-simple-vector ((string (coerce string 'babel:unicode-
string))
                               (start start) (end end))
    (declare (type simple-string string))
    (let ((mapping (lookup-mapping *foreign-string-mappings*
encoding))
          (nul-len (null-terminator-len encoding)))
      (assert (plusp bufsize))
      (multiple-value-bind (size end)
          (funcall (octet-counter mapping) string start end (- bufsize
nul-len))
        (funcall (encoder mapping) string start end buffer 0)
        (dotimes (i nul-len)
          (setf (mem-ref buffer :char (+ size i)) 0))))
    buffer))

--
Best regards,
 budden                          ··················@mail.ru

• Re: bug in a cffi? (crossposting from cffi-devel) Luís Oliveira
  • Re: bug in a cffi? (crossposting from cffi-devel) budden

From: Luís Oliveira
Subject: Re: bug in a cffi? (crossposting from cffi-devel)
Date: Sat, 10 Jan 2009 20:37:08 +0000
Message-ID: <87ocye6gp7.fsf@li14-157.members.linode.com>

budden <···········@mail.ru> writes:

>   I know that posting to devel-lists often fails, so I'm crossposting
> it here.

You have to subscribe first.


>   It looks like lisp-string-to-foreign might overflow buffer if
> offset>0.
>
> (defun lisp-string-to-foreign (string buffer bufsize &key (start 0)
> end offset

While it's probably not very intuitive, it works as advertised:
LISP-STRING-TO-FOREIGN copies at most BUFSIZE-1 bytes into
BUFFER+OFFSET. Feel free to complain about how unintuitive that is, but
please use cffi-devel. :-)

-- 
Luís Oliveira
http://student.dei.uc.pt/~lmoliv/

From: budden
Subject: Re: bug in a cffi? (crossposting from cffi-devel)
Date: Sat, 10 Jan 2009 21:01:38 +0000
Message-ID: <447b1341-d121-492a-a358-b0f1e0fd670c@o4g2000pra.googlegroups.com>

Ok, thanks.