Re: BUG #16200: returned data from ESQL/C FETCH is trampling outside assigned memory for CHAR column

Hi,

> We encounter the following problem with ESQL/C: Imagine a table with

I assume you mean ECPG, right? ESQL/C would be the Informix compiler.

> In the database the CHAR column can contain not only 16 bytes, but 16
> Unicode chars,
> which are longer than 16 bytes if one or more of the chars is an UTF-
> 8
> multibyte
> encoded char.
> ...
> the DATE. Now the function ECPGdo() places the DATE as "MM.DD.YYYY"
> into the area pointed to for the 2nd argument and with this
> overwrites
> the NULL terminator of the string[17] element. Result is later a
> SIGSEGV because the expected string in string[17] is not NULL
> terminated anymore :-)
>
> I would call it a bug, that ECPGdo() puts more than 17 bytes (16
> bytes +
> NULL) as return into the place pointed to by the host var pointer
> when
> the column in the database has more (UTF-8) chars as will fit into
> 16+1 byte.

Actually I am not sure if this is a bug. I do not remember the standard
asking for a null termination at the end of a partial string copy.
Please correct me if I am wrong. What it does ask for is setting the
indicator accordingly. However, you do not mention any indicator, so I
wonder if you checked that one at all. If the string is truncated and
the appropriate error action is not taken, that would definitely
qualify as a bug.

Could you please verify if the indicator is set accordingly?

If you have a small test case to reproduce the issue, please send that
one. Otherwise I can create my own but probably won't have time before
next week.

Thanks

Michael
--
Michael Meskes
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