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libtool/libltdl/ltdl.h
Gary V. Vaughan c823c708c8 Without this patch, lt_dlopen always opens modules with symbol 
visibility set according to the underlying implementation.
Here, we add lt_dlopenadvise() to allow callers to request,
among other things, local or global symbol visibility from the
underlying dlloader:

* libltdl/ltdl.c (LT_DLRESIDENT_FLAG): Removed.
(LT_DLIS_RESIDENT): Use public is_resident info field.
(LT_DLIS_SYMLOCAL, LT_DLIS_SYMGLOBAL): New macros to test for
module symbol visibility status.
(tryall_dlopen): If vtable->module_open() was able to act on
either is_symlocal or is_symglobal hints, store that in
the handle flags.
(lt_dlopenadvise): New function that works like lt_dlopen(),
but accepts an advise type to determine whether to ask
dlloaders to change default symbol visibility.
(lt_dlopen, lt_dlopenext): Just call lt_dlopenadvise() with
the correct parameters.
(lt_dladvise_init, lt_dladvise_destroy): New functions to
initialize and destroy an advise type hint.
(lt_dladvise_ext, lt_dladvise_resident, lt_dladvise_local)
(lt_dladvise_global): Set hints on an advise type.
(openadvise): Factored out of lt_dlopenadvise.
(has_library_ext): Factored out of lt_dlopenadvise.
* libltdl/ltdl.h: Declare all of the above.
(lt_dlinfo): New fields for advise hints.
* libltdl/libltdl/lt_dlloader.h (lt_module_open): Add a new
advise parameter.  Adjust all callers.
(lt_dladvise): New opaque type for advise hints.
* libltdl/libltdl/lt__private.h (lt__advise): Declare
contents of opaque lt_dladvise type.
* libltdl/libltdl/lt_error.h (CONFLICTING_FLAGS): New error
for attempts to have local and global symbol visibility at the
same time.
* libltdl/loaders/dld_link.c, libltdl/loaders/dyld.c,
libltdl/loaders/load_add_on.c, libltdl/loaders/loadlibrary.c,
libltdl/loaders/preopen.c, libltdl/loaders/shl_load.c: Adjust.
* libltdl/loaders/dlopen.c (RTLD_LOCAL, RTLD_GLOBAL): Try to
define these symbols if the system has equivalents.
(vmopen): If unable to act on a caller request to set symbol
visibility, then unset the relevant hints in the advise type.
* tests/lt_dladvise.at: New tests for the above.
* doc/libtool.texi (Libltdl Interface): Updated.
* NEWS: Updated.
2007-05-08 14:38:50 +00:00

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/* ltdl.h -- generic dlopen functions
Copyright (C) 1998-2000, 2004, 2005,
2007 Free Software Foundation, Inc.
Written by Thomas Tanner, 1998
NOTE: The canonical source of this file is maintained with the
GNU Libtool package. Report bugs to bug-libtool@gnu.org.
GNU Libltdl is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.
As a special exception to the GNU Lesser General Public License,
if you distribute this file as part of a program or library that
is built using GNU Libtool, you may include this file under the
same distribution terms that you use for the rest of that program.
GNU Libltdl is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with GNU Libltdl; see the file COPYING.LIB. If not, a
copy can be downloaded from http://www.gnu.org/licenses/lgpl.html,
or obtained by writing to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
/* Only include this header file once. */
#if !defined(LTDL_H)
#define LTDL_H 1
#include <libltdl/lt_system.h>
#include <libltdl/lt_error.h>
#include <libltdl/lt_dlloader.h>
LT_BEGIN_C_DECLS
/* LT_STRLEN can be used safely on NULL pointers. */
#define LT_STRLEN(s) (((s) && (s)[0]) ? strlen (s) : 0)
/* --- DYNAMIC MODULE LOADING API --- */
typedef void * lt_dlhandle; /* A loaded module. */
/* Initialisation and finalisation functions for libltdl. */
LT_SCOPE int lt_dlinit (void);
LT_SCOPE int lt_dlexit (void);
/* Module search path manipulation. */
LT_SCOPE int lt_dladdsearchdir (const char *search_dir);
LT_SCOPE int lt_dlinsertsearchdir (const char *before,
const char *search_dir);
LT_SCOPE int lt_dlsetsearchpath (const char *search_path);
LT_SCOPE const char *lt_dlgetsearchpath (void);
LT_SCOPE int lt_dlforeachfile (
const char *search_path,
int (*func) (const char *filename, void *data),
void *data);
/* User module loading advisors. */
LT_SCOPE int lt_dladvise_init (lt_dladvise *advise);
LT_SCOPE int lt_dladvise_destroy (lt_dladvise *advise);
LT_SCOPE int lt_dladvise_ext (lt_dladvise *advise);
LT_SCOPE int lt_dladvise_resident (lt_dladvise *advise);
LT_SCOPE int lt_dladvise_local (lt_dladvise *advise);
LT_SCOPE int lt_dladvise_global (lt_dladvise *advise);
/* Portable libltdl versions of the system dlopen() API. */
LT_SCOPE lt_dlhandle lt_dlopen (const char *filename);
LT_SCOPE lt_dlhandle lt_dlopenext (const char *filename);
LT_SCOPE lt_dlhandle lt_dlopenadvise (const char *filename,
lt_dladvise advise);
LT_SCOPE void * lt_dlsym (lt_dlhandle handle, const char *name);
LT_SCOPE const char *lt_dlerror (void);
LT_SCOPE int lt_dlclose (lt_dlhandle handle);
/* --- PRELOADED MODULE SUPPORT --- */
/* A preopened symbol. Arrays of this type comprise the exported
symbols for a dlpreopened module. */
typedef struct {
const char *name;
void *address;
} lt_dlsymlist;
typedef int lt_dlpreload_callback_func (lt_dlhandle handle);
LT_SCOPE int lt_dlpreload (const lt_dlsymlist *preloaded);
LT_SCOPE int lt_dlpreload_default (const lt_dlsymlist *preloaded);
LT_SCOPE int lt_dlpreload_open (const char *originator,
lt_dlpreload_callback_func *func);
#define lt_preloaded_symbols lt__PROGRAM__LTX_preloaded_symbols
#define LTDL_SET_PRELOADED_SYMBOLS() LT_STMT_START{ \
extern const lt_dlsymlist lt_preloaded_symbols[]; \
lt_dlpreload_default(lt_preloaded_symbols); \
}LT_STMT_END
/* --- MODULE INFORMATION --- */
/* Associating user data with loaded modules. */
typedef void * lt_dlinterface_id;
typedef int lt_dlhandle_interface (lt_dlhandle handle, const char *id_string);
LT_SCOPE lt_dlinterface_id lt_dlinterface_register (const char *id_string,
lt_dlhandle_interface *iface);
LT_SCOPE void lt_dlinterface_free (lt_dlinterface_id key);
LT_SCOPE void * lt_dlcaller_set_data (lt_dlinterface_id key,
lt_dlhandle handle, void *data);
LT_SCOPE void * lt_dlcaller_get_data (lt_dlinterface_id key,
lt_dlhandle handle);
/* Read only information pertaining to a loaded module. */
typedef struct {
char * filename; /* file name */
char * name; /* module name */
int ref_count; /* number of times lt_dlopened minus
number of times lt_dlclosed. */
unsigned int is_resident:1; /* module can't be unloaded. */
unsigned int is_symglobal:1; /* module symbols can satisfy
subsequently loaded modules. */
unsigned int is_symlocal:1; /* module symbols are only available
locally. */
} lt_dlinfo;
LT_SCOPE const lt_dlinfo *lt_dlgetinfo (lt_dlhandle handle);
LT_SCOPE lt_dlhandle lt_dlhandle_iterate (lt_dlinterface_id iface,
lt_dlhandle place);
LT_SCOPE lt_dlhandle lt_dlhandle_fetch (lt_dlinterface_id iface,
const char *module_name);
LT_SCOPE int lt_dlhandle_map (lt_dlinterface_id iface,
int (*func) (lt_dlhandle handle, void *data),
void *data);
/* Deprecated module residency management API. */
LT_SCOPE int lt_dlmakeresident (lt_dlhandle handle);
LT_SCOPE int lt_dlisresident (lt_dlhandle handle);
#define lt_ptr void *
LT_END_C_DECLS
#endif /*!defined(LTDL_H)*/
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