Re: cope with dlopen(NULL) failing on AIX (was: support AIX 6.1 in config.rpath)

[Bob Friesenhahn]

On Sat, 12 Jan 2008, Ralf Wildenhues wrote:
> I still don't know why it doesn't "just work".  But here is a somewhat
> less crude hack.  OK to apply?  Fixing this could maybe be more nicely
> be done in ltdl.c, but I would like to defer that until after 2.2, and
> with this I don't see any obvious semantic downsides.

This patch looks ok to me.

Bob

> FWIW, this patch requires that LT_INIT is expanded before LTDL_INIT.
>
> Thanks,
> Ralf
>
> 2008-01-12  Ralf Wildenhues  <address@hidden>
>
>         * libltdl/m4/ltdl.m4 (_LTDL_SETUP): Define
>         LTDL_DLOPEN_SELF_WORKS, depending upon lt_cv_dlopen_self.
>         * libltdl/loaders/dlopen.c (vm_open) [!LTDL_DLOPEN_SELF_WORKS]:
>         Fail for dlopen(NULL), so that the preopen loader is used.  This
>         fixes mdemo-exec.test failures on AIX where dlopen(NULL)
>         succeeds but dlsym resolves no symbol.
>         * NEWS: Update.
>         Report by Rainer Tammer.
>
> Index: NEWS
> ===================================================================
> RCS file: /cvsroot/libtool/libtool/NEWS,v
> retrieving revision 1.213
> diff -u -r1.213 NEWS
> --- NEWS        11 Jan 2008 07:08:27 -0000      1.213
> +++ NEWS        12 Jan 2008 14:38:45 -0000
> @@ -116,6 +116,7 @@
>   - Some configure variables have been renamed to fix caching:
>     lt_prog_compiler_pic_works to lt_cv_prog_compiler_pic_works
>     lt_prog_compiler_static_works to lt_cv_prog_compiler_static_works.
> +  - Fix 1.9b regression: lt_dlopen(NULL) works on AIX again.
>   - Loads of smaller bug fixes.
>
>
> Index: libltdl/loaders/dlopen.c
> ===================================================================
> RCS file: /cvsroot/libtool/libtool/libltdl/loaders/dlopen.c,v
> retrieving revision 1.11
> diff -u -r1.11 dlopen.c
> --- libltdl/loaders/dlopen.c    4 Jul 2007 23:05:05 -0000       1.11
> +++ libltdl/loaders/dlopen.c    12 Jan 2008 14:38:45 -0000
> @@ -1,7 +1,7 @@
> /* loader-dlopen.c --  dynamic linking with dlopen/dlsym
>
>    Copyright (C) 1998, 1999, 2000, 2004, 2006,
> -                 2007 Free Software Foundation, Inc.
> +                 2007, 2008 Free Software Foundation, Inc.
>    Written by Thomas Tanner, 1998
>
>    NOTE: The canonical source of this file is maintained with the
> @@ -178,7 +178,14 @@
> #endif
>     }
>
> -  module = dlopen (filename, module_flags);
> +  /* On AIX, dlopen(NULL) succeeds but dlsym of symbols fails.
> +     In this case, fail here to let the preopen loader do the job. */
> +#ifndef LTDL_DLOPEN_SELF_WORKS
> +  if (!filename)
> +    module = NULL;
> +  else
> +#endif
> +    module = dlopen (filename, module_flags);
>
>   if (!module)
>     {
> Index: libltdl/m4/ltdl.m4
> ===================================================================
> RCS file: /cvsroot/libtool/libtool/libltdl/m4/ltdl.m4,v
> retrieving revision 1.39
> diff -u -r1.39 ltdl.m4
> --- libltdl/m4/ltdl.m4  8 Jan 2008 19:39:19 -0000       1.39
> +++ libltdl/m4/ltdl.m4  12 Jan 2008 14:38:46 -0000
> @@ -338,6 +338,12 @@
> m4_require([_LT_CHECK_DLPREOPEN])dnl
> m4_require([_LT_DECL_SED])dnl
>
> +# lt_cv_dlopen_self gets defined by LT_SYS_DLOPEN_SELF, called by LT_INIT
> +if test "$lt_cv_dlopen_self" = yes; then
> +  AC_DEFINE([LTDL_DLOPEN_SELF_WORKS], [1],
> +    [Define if dlopen(NULL) is able to resolve symbols from the main program.])
> +fi
> +
> dnl Don't require this, or it will be expanded earlier than the code
> dnl that sets the variables it relies on:
> _LT_ENABLE_INSTALL
>
>
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> http://lists.gnu.org/mailman/listinfo/bug-libtool

======================================
Bob Friesenhahn
address@hidden, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/