Re: grep-3.5 fails to build on Solaris when libsigsegv is installed

[Paul Eggert]

On 9/28/20 7:02 PM, Bruno Haible wrote:
> #define USE_LIBSIGSEGV (HAVE_XSI_STACK_OVERFLOW_HEURISTIC && HAVE_LIBSIGSEGV)
>
> There seems to be a logic mistake, here.

You're right, it's a typo: there should be a "!" before the 
HAVE_XSI_STACK_OVERFLOW_HEURISTIC. As a result of this mistake, libsigsegv is 
used only on Solaris-like platforms, where it's not needed, and libsigsegv is 
not used on other platforms like GNU/Linux where it can be helpful.

This mistake causes some configuration failures on Solaris on platforms where 
libsigsegv has been installed but grep was not configured correctly. It also 
means that the stack-overflow reporting on GNU/Linux is too generous, in that 
segmentation violations that are not stack overflows get reported as stack 
overflows. I installed the first attached patch to correct this. I would guess 
that this is not much of a problem in practice except when installing on Solaris 
with badly-configured libsigsegv, since from the user's point of view the 
problem is only that when grep crashes the wrong message might be printed.

While looking into this error I noticed that c-stack assumes SIGSTKSZ is an 
integer constant expression, but there have been moves to make it non-constant 
(and this may already be in effect on some platforms). I installed the second 
attached patch to work around this potential portability bug; it has a URL 
pointing to recent discussions in this area.

The third patch merely streamlines 'configure' when running on platforms like 
Solaris that need not use libsigsegv.

0001-c-stack-fix-libsigsegv-typo.patch
Description: Text Data

0002-c-stack-stop-using-SIGSTKSZ.patch
Description: Text Data

0003-c-stack-streamline-Solaris-configuration.patch
Description: Text Data