From: Nobuyoshi Nakada <nobu@...>
Date: 2009-09-11T11:08:59+09:00
Subject: [ruby-core:25526] Re: [Bug #2069] Segfault in rb_enc_associate()

Hi,

At Thu, 10 Sep 2009 00:25:54 +0900,
Jiri Zajpt wrote in [ruby-core:25501]:
> ruby -v: ruby 1.9.1p243 (2009-07-16 revision 24175) [i386-darwin10] 

On darwin10, uname reports i386 but real default target is
x86_64.

> I am having problem with using mysql-ruby driver on Snow
> Leopard. It segfaults in rb_enc_associate() used by
> rb_external_str_new_with_enc() function, so I came up with
> following short example (it also segfaults):

It's a bug of that driver.

> example source code ---------------------------------------------------------------------
> 
> #include <ruby.h>
#include <ruby/encoding.h>

> void
> Init_jzexp()
> {
>     const char* c_str = "test";
>     VALUE string = rb_external_str_new_with_enc(c_str, strlen(c_str), rb_utf8_encoding());

You should have got warning messages here. 

rb_utf8_encoding() returns the pointer to utf-8 rb_encoding,
but undeclared functions are counted as int, and int is smaller
than pointer on x86_64.  Therefore only lower 32bit of the
pointer is used and extended to 64bit, and results a wrong
value.

-- 
Nobu Nakada