libltdl/ltdl.h

   1 /* ltdl.h -- generic dlopen functions
   2
   3    Copyright (C) 1998-2000, 2004-2005, 2007-2008, 2011-2019, 2021-2024
   4    Free Software Foundation, Inc.
   5    Written by Thomas Tanner, 1998
   6
   7    NOTE: The canonical source of this file is maintained with the
   8    GNU Libtool package.  Report bugs to bug-libtool@gnu.org.
   9
  10 GNU Libltdl is free software; you can redistribute it and/or
  11 modify it under the terms of the GNU Lesser General Public
  12 License as published by the Free Software Foundation; either
  13 version 2 of the License, or (at your option) any later version.
  14
  15 As a special exception to the GNU Lesser General Public License,
  16 if you distribute this file as part of a program or library that
  17 is built using GNU Libtool, you may include this file under the
  18 same distribution terms that you use for the rest of that program.
  19
  20 GNU Libltdl is distributed in the hope that it will be useful,
  21 but WITHOUT ANY WARRANTY; without even the implied warranty of
  22 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  23 GNU Lesser General Public License for more details.
  24
  25 You should have received a copy of the GNU Lesser General Public
  26 License along with GNU Libltdl; see the file COPYING.LIB.  If not, a
  27 copy can be downloaded from  http://www.gnu.org/licenses/lgpl.html,
  28 or obtained by writing to the Free Software Foundation, Inc.,
  29 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  30 */
  31
  32 /* Only include this header file once. */
  33 #if !defined LTDL_H
  34 #define LTDL_H 1
  35
  36 #include <libltdl/lt_system.h>
  37 #include <libltdl/lt_error.h>
  38 #include <libltdl/lt_dlloader.h>
  39
  40 LT_BEGIN_C_DECLS
  41
  42
  43 /* LT_STRLEN can be used safely on NULL pointers.  */
  44 #define LT_STRLEN(s)    (((s) && (s)[0]) ? strlen (s) : 0)
  45
  46 /* --- DYNAMIC MODULE LOADING API --- */
  47
  48
  49 typedef struct lt__handle *lt_dlhandle; /* A loaded module.  */
  50
  51 /* Initialisation and finalisation functions for libltdl. */
  52 LT_SCOPE int        lt_dlinit           (void);
  53 LT_SCOPE int        lt_dlexit           (void);
  54
  55 /* Module search path manipulation.  */
  56 LT_SCOPE int        lt_dladdsearchdir    (const char *search_dir);
  57 LT_SCOPE int        lt_dlinsertsearchdir (const char *before,
  58                                                   const char *search_dir);
  59 LT_SCOPE int        lt_dlsetsearchpath   (const char *search_path);
  60 LT_SCOPE const char *lt_dlgetsearchpath  (void);
  61 LT_SCOPE int        lt_dlforeachfile     (
  62                         const char *search_path,
  63                         int (*func) (const char *filename, void *data),
  64                         void *data);
  65
  66 /* User module loading advisors.  */
  67 LT_SCOPE int        lt_dladvise_init     (lt_dladvise *advise);
  68 LT_SCOPE int        lt_dladvise_destroy  (lt_dladvise *advise);
  69 LT_SCOPE int        lt_dladvise_ext      (lt_dladvise *advise);
  70 LT_SCOPE int        lt_dladvise_resident (lt_dladvise *advise);
  71 LT_SCOPE int        lt_dladvise_local    (lt_dladvise *advise);
  72 LT_SCOPE int        lt_dladvise_global   (lt_dladvise *advise);
  73 LT_SCOPE int        lt_dladvise_preload  (lt_dladvise *advise);
  74
  75 /* Portable libltdl versions of the system dlopen() API. */
  76 LT_SCOPE lt_dlhandle lt_dlopen          (const char *filename);
  77 LT_SCOPE lt_dlhandle lt_dlopenext       (const char *filename);
  78 LT_SCOPE lt_dlhandle lt_dlopenadvise    (const char *filename,
  79                                          lt_dladvise advise);
  80 LT_SCOPE void *     lt_dlsym            (lt_dlhandle handle, const char *name);
  81 LT_SCOPE const char *lt_dlerror         (void);
  82 LT_SCOPE int        lt_dlclose          (lt_dlhandle handle);
  83
  84
  85
  86 /* --- PRELOADED MODULE SUPPORT --- */
  87
  88
  89 /* A preopened symbol. Arrays of this type comprise the exported
  90    symbols for a dlpreopened module. */
  91 typedef struct {
  92   const char *name;
  93   void       *address;
  94 } lt_dlsymlist;
  95
  96 typedef int lt_dlpreload_callback_func (lt_dlhandle handle);
  97
  98 LT_SCOPE int    lt_dlpreload         (const lt_dlsymlist *preloaded);
  99 LT_SCOPE int    lt_dlpreload_default (const lt_dlsymlist *preloaded);
 100 LT_SCOPE int    lt_dlpreload_open    (const char *originator,
 101                                       lt_dlpreload_callback_func *func);
 102
 103 #define lt_preloaded_symbols    lt__PROGRAM__LTX_preloaded_symbols
 104 /* Ensure C linkage.  */
 105 extern LT_DLSYM_CONST lt_dlsymlist lt__PROGRAM__LTX_preloaded_symbols[];
 106
 107 #define LTDL_SET_PRELOADED_SYMBOLS() \
 108         lt_dlpreload_default(lt_preloaded_symbols)
 109
 110
 111
 112 /* --- MODULE INFORMATION --- */
 113
 114
 115 /* Associating user data with loaded modules. */
 116 typedef void * lt_dlinterface_id;
 117 typedef int lt_dlhandle_interface (lt_dlhandle handle, const char *id_string);
 118
 119 LT_SCOPE lt_dlinterface_id lt_dlinterface_register (const char *id_string,
 120                                           lt_dlhandle_interface *iface);
 121 LT_SCOPE void   lt_dlinterface_free (lt_dlinterface_id key);
 122 LT_SCOPE void * lt_dlcaller_set_data  (lt_dlinterface_id key,
 123                                           lt_dlhandle handle, void *data);
 124 LT_SCOPE void * lt_dlcaller_get_data  (lt_dlinterface_id key,
 125                                           lt_dlhandle handle);
 126
 127
 128 /* Read only information pertaining to a loaded module. */
 129 typedef struct {
 130   char *        filename;       /* file name */
 131   char *        name;           /* module name */
 132   int           ref_count;      /* number of times lt_dlopened minus
 133                                    number of times lt_dlclosed. */
 134   unsigned int  is_resident:1;  /* module can't be unloaded. */
 135   unsigned int  is_symglobal:1; /* module symbols can satisfy
 136                                    subsequently loaded modules.  */
 137   unsigned int  is_symlocal:1;  /* module symbols are only available
 138                                    locally. */
 139 } lt_dlinfo;
 140
 141 LT_SCOPE const lt_dlinfo *lt_dlgetinfo      (lt_dlhandle handle);
 142
 143 LT_SCOPE lt_dlhandle    lt_dlhandle_iterate (lt_dlinterface_id iface,
 144                                              lt_dlhandle place);
 145 LT_SCOPE lt_dlhandle    lt_dlhandle_fetch   (lt_dlinterface_id iface,
 146                                              const char *module_name);
 147 LT_SCOPE int            lt_dlhandle_map     (lt_dlinterface_id iface,
 148                                 int (*func) (lt_dlhandle handle, void *data),
 149                                 void *data);
 150
 151
 152
 153 /* Deprecated module residency management API. */
 154 LT_SCOPE int        lt_dlmakeresident   (lt_dlhandle handle);
 155 LT_SCOPE int        lt_dlisresident     (lt_dlhandle handle);
 156
 157 #define lt_ptr void *
 158
 159 LT_END_C_DECLS
 160
 161 #endif /*!defined LTDL_H*/