[PATCH] BZ #13979- A warning should be issued if FORTIFY_SOURCE is requested but not enabled

[Andreas Jaeger]

On 05/07/2012 11:15 PM, Roland McGrath wrote:
>> 	* include/features.h: Warn if user requests FORTIFY_SOURCE checking
>> 	but the checks are disabled for any reason.
>
> Use the correct name in the log: _FORTIFY_SOURCE.
>
>> +#if defined _FORTIFY_SOURCE&&  _FORTIFY_SOURCE>  0&&  __USE_FORTIFY_LEVEL == 0
>> +# warning _FORTIFY_SOURCE requested but disabled
>> +#endif
>
> It's probably more helpful to say something specific:
>
> # if !defined __OPTIMIZE__ || __OPTIMIZE__<= 0
> #  warning _FORTIFY_SOURCE requires compiling with optimization (-O)
> # elif !__GNUC_PREREQ (4, 1)
> #  warning _FORTIFY_SOURCE is only supported with GCC 4.1 or later
> # else
> #  warning _FORTIFY_SOURCE is not available for mysterious reasons
> # endif
>
> It also seems cleaner to move this into the #if nest that actually sets
> __USE_FORTIFY_LEVEL, perhaps reorganizing that a little as needed.

Good idea.

Here's what I'm testing now:

#if defined _FORTIFY_SOURCE && _FORTIFY_SOURCE > 0 \
     && __GNUC_PREREQ (4, 1) && defined __OPTIMIZE__ && __OPTIMIZE__ > 0
# if _FORTIFY_SOURCE > 1
#  define __USE_FORTIFY_LEVEL 2
# else
#  define __USE_FORTIFY_LEVEL 1
# endif
#else
# define __USE_FORTIFY_LEVEL 0
# if !defined __OPTIMIZE__ || __OPTIMIZE__ <= 0
#  warning _FORTIFY_SOURCE requires compiling with optimization (-O)
# elif !__GNUC_PREREQ (4, 1)
#  warning _FORTIFY_SOURCE is only supported with GCC 4.1 or later
# endif
#endif


Andreas
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