Re: I'm having a crashing problem with FreeTDS under OSX

I put some printfs in around the free and it appears to be pointing to  
a valid date format.
If I just comment out the free it then seems to fail on the next free  
the code hits (and of course leaks;)
It is almost as if the heap is getting corrupted somehow it freeing up  
allocated memory is crapping out.

What I might try doing is something like the following

free(malloc(100));

and see what happens

Daniel

On 06/03/2009, at 4:52 PM, James K. Lowden wrote:

> Daniel Parnell wrote:
>> 	here is the first little bit of the stack trace for the first
>> 	crash
>> I'm seeing.
>>
>> Program received signal EXC_BAD_ACCESS, Could not access memory.
>> Reason: KERN_PROTECTION_FAILURE at address: 0x00000016
>> 0x0010f7fa in free ()
>> (gdb) bt
>> #0  0x0010f7fa in free ()
>> #1  0x02f55c38 in _SQLAllocEnv (phenv=0x812c70) at odbc.c:1353
>
> Bug.  Eh.  The pointer being freed might not have been allocated, and
> isn't zeroed when initialized.
>
> 	free(ctx->locale->date_fmt);
>
> Locale is allocated by tds_alloc_locale() and initialized by
> tds_parse_locale().  Something's a little wrong, because
> tds_parse_locale() should find a proper date format string in
> locales.conf.  In case it doesn't, though, *nothing* initializes the
> memory; it's just pointing to random space.  A little while later, the
> ODBC driver fastidiously frees the tiny string it thinks was  
> allocated,
> and you send a message to the list.
>
> I would double-check what's going on with TDSDUMPCONFIG, which  
> should show
> a locales.conf being read and the date_fmt being initialized. But this
> patch wouldn't do any harm:
>
> RCS file: /cvsroot/freetds/freetds/src/tds/mem.c,v
> retrieving revision 1.175.2.2
> diff -u -r1.175.2.2 mem.c
> --- src/tds/mem.c       5 Nov 2008 14:56:12 -0000       1.175.2.2
> +++ src/tds/mem.c       6 Mar 2009 05:49:34 -0000
> @@ -656,7 +656,7 @@
> {
>        TDSLOCALE *locale;
>
> -       TEST_MALLOC(locale, TDSLOCALE);
> +       TEST_CALLOC(locale, TDSLOCALE, 1);
>        return locale;
>
>       Cleanup:
>
> HTH.
>
> --jkl
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