Re: [PATCH, jit]: Robustify vasprintf error checks

[David Malcolm <dmalcolm at redhat dot com>]

On Fri, 2015-03-13 at 17:53 +0100, Uros Bizjak wrote:
> Hello!
> 
> As documented in [1] asprintf and vasprintf return:
> 
> --quote--
> Return value:
> 
> Both functions set *ret to be a pointer to a malloc()'d buffer
> sufficiently large to hold the formatted string. This pointer should
> be passed to free() to release the allocated storage when it is no
> longer needed.
> 
> The integer value returned by these functions is the number of
> characters that were output to the newly allocated string (excluding
> the final '\0'). To put it differently, the return value will match
> that of strlen(*ret).
> 
> Upon failure, the returned value will be -1, and *ret will be set to NULL.
> 
> Note: Upon failure, other implementations may forget to set *ret and
> leave it in an undefined state. Some other implementations may always
> set *ret upon failure but forget to assign -1 for the return value in
> some edge cases.
> --/quote--
> 
> Based on the note above, the attached patch robustifies vasprintf
> return value checks in jit/jit-recording.c. Actually, the same checks
> are already implemented in function oprint, around line 1655 in
> gengtype.c.

> 2015-02-25  Uros Bizjak  <ubizjak@gmail.com>
> 
>     * jit-recording.c (dump::write): Also check vasprintf return value.
>     (recording::context::add_error_va): Ditto.
>     (recording::string::from_printf): Ditto.
> 
> The patch was bootstrapped and regression tested on x86_64-linux-gnu.
> 
> OK for mainline?

Thanks.

I assume that we can rely that any vasprintf implementation manages on
failure to at least either write NULL to *ret or to return -1, even if
some of them fail to do both?

OK for trunk.

> 
> [1] http://asprintf.insanecoding.org/
> 
> Uros.