sablevm-developer

[Sablevm-developer] SA_SIGINFO undefined

[Julio M. M. V. <jm...@me...>]

Hi again,

the last problem I found while building sablevm under NetBSD is that it didn't
find SA_SIGINFO defined.  Checked the sources, and <signal.h> is included
correctly, so the problem is coming from somewhere else.

Digging a bit in configure, I found that it defines _POSIX_C_SOURCE.  The
problem is that defining this disables SA_SIGINFO, because siginfo is not
POSIX compliant.  According to the siginfo(2) manpage:

STANDARDS
     The siginfo_t type conforms to X/Open System Interfaces and Headers
     Issue 5 (``XSH5'').

Removing that definition lets the code work (because, SA_SIGINFO is defined
if no _* macros are explicitly defined), but I don't think this is the
solution you want.

Instead, and according to the standards text I posted before, defining
_XOPEN_SOURCE to 500 lets it work fine.  This seems better, and is easy
to fix:

--- configure.ac.orig	2004-03-20 23:02:08.000000000 +0100
+++ configure.ac
@@ -21,6 +21,7 @@ AC_DEFINE_UNQUOTED(_SABLEVM_PACKAGE_VERS
 
 AC_DEFINE(_REENTRANT,1,link with reentrant library functions)
 AC_DEFINE(_POSIX_C_SOURCE,199506L,link with POSIX library functions)
+AC_DEFINE(_XOPEN_SOURCE,500,link with XOpen library functions)
 
 dnl *** uncomment if you want to insert a magic value in every object instance for debugging ***
 dnl AC_DEFINE(MAGIC,1,put "SableVM" in every instance)

Cheers

-- 
Julio M. Merino Vidal <jm...@me...>
The NetBSD Project - http://www.NetBSD.org/

Re: [Sablevm-developer] SA_SIGINFO undefined

[Etienne G. <gag...@uq...>]

Hi Julio,

You've made the Hall of Fame.  Your name is in SableVM's AUTHORS file
(staging branch), along with your 3 patches applied.

Thanks a lot!

Etienne

-- 
Etienne M. Gagnon, Ph.D.             http://www.info.uqam.ca/~egagnon/
SableVM:                                       http://www.sablevm.org/
SableCC:                                       http://www.sablecc.org/

Re: [Sablevm-developer] SA_SIGINFO undefined

[Julio M. M. V. <jm...@me...>]

On Thu, 25 Mar 2004 23:45:58 -0500
Etienne Gagnon <gag...@uq...> wrote:

> Hi Julio,
> 
> You've made the Hall of Fame.  Your name is in SableVM's AUTHORS file
> (staging branch), along with your 3 patches applied.
> 
> Thanks a lot!

Wow :-)  You're welcome.

But now, back again to the SA_SIGINFO stuff.  The patch I sent yesterday really
fixed sablevm, but only for NetBSD-current.  Today I gave a try under NetBSD
1.6.2 (the stable branch, which frankly is getting out of date and misses stuff
like siginfo)... you guessed right, the build failed.

I've got a patch that fixes it, though I'm not sure it's 100% right (because
some signal handling is left out).  Here is what I did:

- Check for the presence of siginfo_t from configure.  If it's not present,
  completely disable "signals for exceptions" unconditionally (with the
  appropiate warning to let the user know what's going on).  I assume that
  if siginfo_t is not present, SA_SIGINFO is not either (and viceversa).

- If siginfo is not present, define siginfo_t to void.  This is used just once
  in a function prototype, and the siginfo_t parameter is never used when
  "signals for exceptions" are disabled.  Therefore, setting it to a void
  pointer lets it work (because the parameter is not used), and the
  workaround is completely transparent to the code.

- Move some #ifdef's around in error.c, to protect more code that uses siginfo
  stuff.

So, if this rationale is ok, the attached patch should do it correctly ;-)

Cheers

-- 
Julio M. Merino Vidal <jm...@me...>
The NetBSD Project - http://www.NetBSD.org/

Re: [Sablevm-developer] SA_SIGINFO undefined

[Grzegorz B. P. <ga...@de...>]

W li=B6cie z pi=B1, 26-03-2004, godz. 18:18, Julio M. Merino Vidal pisze:=
=20
> - Move some #ifdef's around in error.c, to protect more code that uses =
siginfo
>   stuff.

The only problem is, that sometimes you want to disable signals for
performance resons and still be able to send SIGQUIT to get stack dump.
The --disable-signals-for-exceptions has it in its name. It is not
a general switch that enables/disables signals.

I think that based on the autodetection you wrote you could define
a symbol in configure, then use it to either disable SIGQUIT handling
completly, or to enable some special version of this handler.

Cheers,

					Grzegorz B. Prokopski
--=20
Grzegorz B. Prokopski <ga...@de...>
Debian GNU/Linux      http://www.debian.org
SableVM - LGPLed JVM  http://www.sablevm.org
Why SableVM ?!?       http://devel.sablevm.org/wiki/WhySableVM

Re: [Sablevm-developer] SA_SIGINFO undefined

[Julio M. M. V. <jm...@me...>]

On Sat, 27 Mar 2004 12:16:24 -0500
"Grzegorz B. Prokopski" <ga...@de...> wrote:

> W li=B6cie z pi=B1, 26-03-2004, godz. 18:18, Julio M. Merino Vidal pisze:=
=20
> > - Move some #ifdef's around in error.c, to protect more code that uses =
siginfo
> >   stuff.
>=20
> The only problem is, that sometimes you want to disable signals for
> performance resons and still be able to send SIGQUIT to get stack dump.
> The --disable-signals-for-exceptions has it in its name. It is not
> a general switch that enables/disables signals.
>=20
> I think that based on the autodetection you wrote you could define
> a symbol in configure, then use it to either disable SIGQUIT handling
> completly, or to enable some special version of this handler.

That's indeed better.  The attached patch should do it: it checks for sigin=
fo
and, if it's not available, it disables all signals; but if it is, "signals
for exceptions" behavior is preserved.  Also avoids the ugly "#define sigin=
fo_t
void" hack of the previous patch.

This should help Cygwin too, as I read in another post ;)

Let's see if it's better now.  Cheers.

--=20
Julio M. Merino Vidal <jm...@me...>
The NetBSD Project - http://www.NetBSD.org/

Re: [Sablevm-developer] SA_SIGINFO undefined

[Etienne G. <gag...@uq...>]

Julio M. Merino Vidal wrote:
> Let's see if it's better now.  Cheers.

Hi Julio,

I've made some modifications to the configuration code, and the code is
now in staging.

Thanks a lot!

Etienne

-- 
Etienne M. Gagnon, Ph.D.             http://www.info.uqam.ca/~egagnon/
SableVM:                                       http://www.sablevm.org/
SableCC:                                       http://www.sablecc.org/