1 /* GMODULE - GLIB wrapper code for dynamic module loading
2 * Copyright (C) 1998 Tim Janik
3 *
4 * SPDX-License-Identifier: LGPL-2.1-or-later
5 *
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * This library is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with this library; if not, see <http://www.gnu.org/licenses/>.
18 */
19
20 /*
21 * Modified by the GLib Team and others 1997-2000. See the AUTHORS
22 * file for a list of people on the GLib Team. See the ChangeLog
23 * files for a list of changes. These files are distributed with
24 * GLib at ftp://ftp.gtk.org/pub/gtk/.
25 */
26
27 /*
28 * MT safe
29 */
30
31 #include "config.h"
32
33 #include "glib.h"
34 #include "gmodule.h"
35
36 #include <errno.h>
37 #include <string.h>
38 #include <sys/types.h>
39 #include <sys/stat.h>
40 #include <fcntl.h>
41 #ifdef G_OS_UNIX
42 #include <unistd.h>
43 #endif
44 #ifdef G_OS_WIN32
45 #include <io.h> /* For open() and close() prototypes. */
46 #endif
47
48 #ifndef O_CLOEXEC
49 #define O_CLOEXEC 0
50 #endif
51
52 #include "gmoduleconf.h"
53 #include "gstdio.h"
54
55
56 /**
57 * GModule:
58 *
59 * The #GModule struct is an opaque data structure to represent a
60 * [dynamically-loaded module][glib-Dynamic-Loading-of-Modules].
61 * It should only be accessed via the following functions.
62 */
63
64 /**
65 * GModuleCheckInit:
66 * @module: the #GModule corresponding to the module which has just been loaded
67 *
68 * Specifies the type of the module initialization function.
69 * If a module contains a function named g_module_check_init() it is called
70 * automatically when the module is loaded. It is passed the #GModule structure
71 * and should return %NULL on success or a string describing the initialization
72 * error.
73 *
74 * Returns: %NULL on success, or a string describing the initialization error
75 */
76
77 /**
78 * GModuleUnload:
79 * @module: the #GModule about to be unloaded
80 *
81 * Specifies the type of the module function called when it is unloaded.
82 * If a module contains a function named g_module_unload() it is called
83 * automatically when the module is unloaded.
84 * It is passed the #GModule structure.
85 */
86
87 /**
88 * G_MODULE_SUFFIX:
89 *
90 * Expands to a shared library suffix for the current platform without the
91 * leading dot. On Unixes this is "so", and on Windows this is "dll".
92 *
93 * Deprecated: 2.76: Use g_module_open() instead with @module_name as the
94 * basename of the file_name argument. You will get the wrong results using
95 * this macro most of the time:
96 *
97 * 1. The suffix on macOS is usually 'dylib', but it's 'so' when using
98 * Autotools, so there's no way to get the suffix correct using
99 * a pre-processor macro.
100 * 2. Prefixes also vary in a platform-specific way. You may or may not have
101 * a 'lib' prefix for the name on Windows and on Cygwin the prefix is
102 * 'cyg'.
103 * 3. The library name itself can vary per platform. For instance, you may
104 * want to load foo-1.dll on Windows and libfoo.1.dylib on macOS.
105 *
106 * g_module_open() takes care of all this by searching the filesystem for
107 * combinations of possible suffixes and prefixes.
108 */
109
110 /**
111 * G_MODULE_EXPORT:
112 *
113 * Used to declare functions exported by libraries or modules.
114 *
115 * When compiling for Windows, it marks the symbol as `dllexport`.
116 *
117 * When compiling for Linux and Unices, it marks the symbol as having `default`
118 * visibility. This is no-op unless the code is being compiled with a
119 * non-default
120 * [visibility flag](https://gcc.gnu.org/onlinedocs/gcc/Code-Gen-Options.html#index-fvisibility-1260)
121 * such as `hidden`.
122 *
123 * This macro must only be used when compiling a shared module. Modules that
124 * support both shared and static linking should define their own macro that
125 * expands to %G_MODULE_EXPORT when compiling the shared module, but is empty
126 * when compiling the static module on Windows.
127 */
128
129 /**
130 * G_MODULE_IMPORT:
131 *
132 * Used to declare functions imported from modules.
133 */
134
135 /* We maintain a list of modules, so we can reference count them.
136 * That's needed because some platforms don't support references counts on
137 * modules. Also, the module for the program itself is kept separately for
138 * faster access and because it has special semantics.
139 */
140
141
142 /* --- structures --- */
143 struct _GModule
144 {
145 gchar *file_name;
146 gpointer handle;
147 guint ref_count : 31;
148 guint is_resident : 1;
149 GModuleUnload unload;
150 GModule *next;
151 };
152
153
154 /* --- prototypes --- */
155 static gpointer _g_module_open (const gchar *file_name,
156 gboolean bind_lazy,
157 gboolean bind_local,
158 GError **error);
159 static void _g_module_close (gpointer handle);
160 static gpointer _g_module_self (void);
161 static gpointer _g_module_symbol (gpointer handle,
162 const gchar *symbol_name);
163 #if (G_MODULE_IMPL != G_MODULE_IMPL_DL) && (G_MODULE_IMPL != G_MODULE_IMPL_AR)
164 static gchar* _g_module_build_path (const gchar *directory,
165 const gchar *module_name);
166 #else
167 /* Implementation is in gmodule-deprecated.c */
168 gchar* _g_module_build_path (const gchar *directory,
169 const gchar *module_name);
170 #endif
171 static inline void g_module_set_error (const gchar *error);
172 static inline GModule* g_module_find_by_handle (gpointer handle);
173 static inline GModule* g_module_find_by_name (const gchar *name);
174
175
176 /* --- variables --- */
177 static GModule *modules = NULL;
178 static GModule *main_module = NULL;
179 static GPrivate module_error_private = G_PRIVATE_INIT (g_free);
180 static gboolean module_debug_initialized = FALSE;
181 static guint module_debug_flags = 0;
182
183
184 /* --- inline functions --- */
185 static inline GModule*
186 g_module_find_by_handle (gpointer handle)
187 {
188 GModule *module;
189 GModule *retval = NULL;
190
191 if (main_module && main_module->handle == handle)
192 retval = main_module;
193 else
194 for (module = modules; module; module = module->next)
195 if (handle == module->handle)
196 {
197 retval = module;
198 break;
199 }
200
201 return retval;
202 }
203
204 static inline GModule*
205 g_module_find_by_name (const gchar *name)
206 {
207 GModule *module;
208 GModule *retval = NULL;
209
210 for (module = modules; module; module = module->next)
211 if (strcmp (name, module->file_name) == 0)
212 {
213 retval = module;
214 break;
215 }
216
217 return retval;
218 }
219
220 static inline void
221 g_module_set_error_unduped (gchar *error)
222 {
223 g_private_replace (&module_error_private, error);
224 errno = 0;
225 }
226
227 static inline void
228 g_module_set_error (const gchar *error)
229 {
230 g_module_set_error_unduped (g_strdup (error));
231 }
232
233
234 /* --- include platform specific code --- */
235 #define SUPPORT_OR_RETURN(rv) { g_module_set_error (NULL); }
236 #if (G_MODULE_IMPL == G_MODULE_IMPL_DL)
237 #include "gmodule-dl.c"
238 #elif (G_MODULE_IMPL == G_MODULE_IMPL_WIN32)
239 #include "gmodule-win32.c"
240 #elif (G_MODULE_IMPL == G_MODULE_IMPL_AR)
241 #include "gmodule-ar.c"
242 #else
243 #undef SUPPORT_OR_RETURN
244 #define SUPPORT_OR_RETURN(rv) { g_module_set_error ("dynamic modules are " \
245 "not supported by this system"); return rv; }
246 static gpointer
247 _g_module_open (const gchar *file_name,
248 gboolean bind_lazy,
249 gboolean bind_local,
250 GError **error)
251 {
252 g_module_set_error (NULL);
253 return NULL;
254 }
255 static void
256 _g_module_close (gpointer handle)
257 {
258 }
259 static gpointer
260 _g_module_self (void)
261 {
262 return NULL;
263 }
264 static gpointer
265 _g_module_symbol (gpointer handle,
266 const gchar *symbol_name)
267 {
268 return NULL;
269 }
270 static gchar*
271 _g_module_build_path (const gchar *directory,
272 const gchar *module_name)
273 {
274 return NULL;
275 }
276 #endif /* no implementation */
277
278 /**
279 * G_MODULE_ERROR:
280 *
281 * The error domain of the #GModule API.
282 *
283 * Since: 2.70
284 */
285 G_DEFINE_QUARK (g-module-error-quark, g_module_error)
286
287 /* --- functions --- */
288
289 /**
290 * g_module_supported:
291 *
292 * Checks if modules are supported on the current platform.
293 *
294 * Returns: %TRUE if modules are supported
295 */
296 gboolean
297 g_module_supported (void)
298 {
299 SUPPORT_OR_RETURN (FALSE);
300
301 return TRUE;
302 }
303
304 static gchar*
305 parse_libtool_archive (const gchar* libtool_name)
306 {
307 const guint TOKEN_DLNAME = G_TOKEN_LAST + 1;
308 const guint TOKEN_INSTALLED = G_TOKEN_LAST + 2;
309 const guint TOKEN_LIBDIR = G_TOKEN_LAST + 3;
310 gchar *lt_dlname = NULL;
311 gboolean lt_installed = TRUE;
312 gchar *lt_libdir = NULL;
313 gchar *name;
314 GTokenType token;
315 GScanner *scanner;
316
317 int fd = g_open (libtool_name, O_RDONLY | O_CLOEXEC, 0);
318 if (fd < 0)
319 {
320 gchar *display_libtool_name = g_filename_display_name (libtool_name);
321 g_module_set_error_unduped (g_strdup_printf ("failed to open libtool archive ‘%s’", display_libtool_name));
322 g_free (display_libtool_name);
323 return NULL;
324 }
325 /* search libtool's dlname specification */
326 scanner = g_scanner_new (NULL);
327 g_scanner_input_file (scanner, fd);
328 scanner->config->symbol_2_token = TRUE;
329 g_scanner_scope_add_symbol (scanner, 0, "dlname",
330 GUINT_TO_POINTER (TOKEN_DLNAME));
331 g_scanner_scope_add_symbol (scanner, 0, "installed",
332 GUINT_TO_POINTER (TOKEN_INSTALLED));
333 g_scanner_scope_add_symbol (scanner, 0, "libdir",
334 GUINT_TO_POINTER (TOKEN_LIBDIR));
335 while (!g_scanner_eof (scanner))
336 {
337 token = g_scanner_get_next_token (scanner);
338 if (token == TOKEN_DLNAME || token == TOKEN_INSTALLED ||
339 token == TOKEN_LIBDIR)
340 {
341 if (g_scanner_get_next_token (scanner) != '=' ||
342 g_scanner_get_next_token (scanner) !=
343 (token == TOKEN_INSTALLED ?
344 G_TOKEN_IDENTIFIER : G_TOKEN_STRING))
345 {
346 gchar *display_libtool_name = g_filename_display_name (libtool_name);
347 g_module_set_error_unduped (g_strdup_printf ("unable to parse libtool archive ‘%s’", display_libtool_name));
348 g_free (display_libtool_name);
349
350 g_free (lt_dlname);
351 g_free (lt_libdir);
352 g_scanner_destroy (scanner);
353 close (fd);
354
355 return NULL;
356 }
357 else
358 {
359 if (token == TOKEN_DLNAME)
360 {
361 g_free (lt_dlname);
362 lt_dlname = g_strdup (scanner->value.v_string);
363 }
364 else if (token == TOKEN_INSTALLED)
365 lt_installed =
366 strcmp (scanner->value.v_identifier, "yes") == 0;
367 else /* token == TOKEN_LIBDIR */
368 {
369 g_free (lt_libdir);
370 lt_libdir = g_strdup (scanner->value.v_string);
371 }
372 }
373 }
374 }
375
376 if (!lt_installed)
377 {
378 gchar *dir = g_path_get_dirname (libtool_name);
379 g_free (lt_libdir);
380 lt_libdir = g_strconcat (dir, G_DIR_SEPARATOR_S ".libs", NULL);
381 g_free (dir);
382 }
383
384 g_clear_pointer (&scanner, g_scanner_destroy);
385 close (g_steal_fd (&fd));
386
387 if (lt_libdir == NULL || lt_dlname == NULL)
388 {
389 gchar *display_libtool_name = g_filename_display_name (libtool_name);
390 g_module_set_error_unduped (g_strdup_printf ("unable to parse libtool archive ‘%s’", display_libtool_name));
391 g_free (display_libtool_name);
392
393 return NULL;
394 }
395
396 name = g_strconcat (lt_libdir, G_DIR_SEPARATOR_S, lt_dlname, NULL);
397
398 g_free (lt_dlname);
399 g_free (lt_libdir);
400
401 return name;
402 }
403
404 enum
405 {
406 G_MODULE_DEBUG_RESIDENT_MODULES = 1 << 0,
407 G_MODULE_DEBUG_BIND_NOW_MODULES = 1 << 1
408 };
409
410 static void
411 _g_module_debug_init (void)
412 {
413 const GDebugKey keys[] = {
414 { "resident-modules", G_MODULE_DEBUG_RESIDENT_MODULES },
415 { "bind-now-modules", G_MODULE_DEBUG_BIND_NOW_MODULES }
416 };
417 const gchar *env;
418
419 env = g_getenv ("G_DEBUG");
420
421 module_debug_flags =
422 !env ? 0 : g_parse_debug_string (env, keys, G_N_ELEMENTS (keys));
423
424 module_debug_initialized = TRUE;
425 }
426
427 static GRecMutex g_module_global_lock;
428
429 /**
430 * g_module_open_full:
431 * @file_name: (nullable): the name or path to the file containing the module,
432 * or %NULL to obtain a #GModule representing the main program itself
433 * @flags: the flags used for opening the module. This can be the
434 * logical OR of any of the #GModuleFlags
435 * @error: #GError.
436 *
437 * Opens a module. If the module has already been opened, its reference count
438 * is incremented. If not, the module is searched in the following order:
439 *
440 * 1. If @file_name exists as a regular file, it is used as-is; else
441 * 2. If @file_name doesn't have the correct suffix and/or prefix for the
442 * platform, then possible suffixes and prefixes will be added to the
443 * basename till a file is found and whatever is found will be used; else
444 * 3. If @file_name doesn't have the ".la"-suffix, ".la" is appended. Either
445 * way, if a matching .la file exists (and is a libtool archive) the
446 * libtool archive is parsed to find the actual file name, and that is
447 * used.
448 *
449 * At the end of all this, we would have a file path that we can access on
450 * disk, and it is opened as a module. If not, @file_name is opened as
451 * a module verbatim in the hopes that the system implementation will somehow
452 * be able to access it.
453 *
454 * Returns: a #GModule on success, or %NULL on failure
455 *
456 * Since: 2.70
457 */
458 GModule*
459 g_module_open_full (const gchar *file_name,
460 GModuleFlags flags,
461 GError **error)
462 {
463 GModule *module;
464 gpointer handle = NULL;
465 gchar *name = NULL;
466
467 SUPPORT_OR_RETURN (NULL);
468
469 g_return_val_if_fail (error == NULL || *error == NULL, NULL);
470
471 g_rec_mutex_lock (&g_module_global_lock);
472
473 if (G_UNLIKELY (!module_debug_initialized))
474 _g_module_debug_init ();
475
476 if (module_debug_flags & G_MODULE_DEBUG_BIND_NOW_MODULES)
477 flags &= ~G_MODULE_BIND_LAZY;
478
479 if (!file_name)
480 {
481 if (!main_module)
482 {
483 handle = _g_module_self ();
484 /* On Android 64 bit, RTLD_DEFAULT is (void *)0x0
485 * so it always fails to create main_module if file_name is NULL */
486 #if !defined(__BIONIC__) || !defined(__LP64__)
487 if (handle)
488 #endif
489 {
490 main_module = g_new (GModule, 1);
491 main_module->file_name = NULL;
492 main_module->handle = handle;
493 main_module->ref_count = 1;
494 main_module->is_resident = TRUE;
495 main_module->unload = NULL;
496 main_module->next = NULL;
497 }
498 }
499 else
500 main_module->ref_count++;
501
502 g_rec_mutex_unlock (&g_module_global_lock);
503 return main_module;
504 }
505
506 /* we first search the module list by name */
507 module = g_module_find_by_name (file_name);
508 if (module)
509 {
510 module->ref_count++;
511
512 g_rec_mutex_unlock (&g_module_global_lock);
513 return module;
514 }
515
516 /* check whether we have a readable file right away */
517 if (g_file_test (file_name, G_FILE_TEST_IS_REGULAR))
518 name = g_strdup (file_name);
519 /* try completing file name with standard library suffix */
520 if (!name)
521 {
522 char *basename, *dirname;
523 size_t prefix_idx = 0, suffix_idx = 0;
524 const char *prefixes[2] = {0}, *suffixes[2] = {0};
525
526 basename = g_path_get_basename (file_name);
527 dirname = g_path_get_dirname (file_name);
528 #ifdef G_OS_WIN32
529 if (!g_str_has_prefix (basename, "lib"))
530 prefixes[prefix_idx++] = "lib";
531 prefixes[prefix_idx++] = "";
532 if (!g_str_has_suffix (basename, ".dll"))
533 suffixes[suffix_idx++] = ".dll";
534 #else
535 #ifdef __CYGWIN__
536 if (!g_str_has_prefix (basename, "cyg"))
537 prefixes[prefix_idx++] = "cyg";
538 #else
539 if (!g_str_has_prefix (basename, "lib"))
540 prefixes[prefix_idx++] = "lib";
541 else
542 /* People commonly pass `libfoo` as the file_name and want us to
543 * auto-detect the suffix as .la or .so, etc. We need to also find
544 * .dylib and .dll in those cases. */
545 prefixes[prefix_idx++] = "";
546 #endif
547 #ifdef __APPLE__
548 if (!g_str_has_suffix (basename, ".dylib") &&
549 !g_str_has_suffix (basename, ".so"))
550 {
551 suffixes[suffix_idx++] = ".dylib";
552 suffixes[suffix_idx++] = ".so";
553 }
554 #else
555 if (!g_str_has_suffix (basename, ".so"))
556 suffixes[suffix_idx++] = ".so";
557 #endif
558 #endif
559 for (guint i = 0; i < prefix_idx; i++)
560 {
561 for (guint j = 0; j < suffix_idx; j++)
562 {
563 name = g_strconcat (dirname, G_DIR_SEPARATOR_S, prefixes[i],
564 basename, suffixes[j], NULL);
565 if (g_file_test (name, G_FILE_TEST_IS_REGULAR))
566 goto name_found;
567 g_free (name);
568 name = NULL;
569 }
570 }
571 name_found:
572 g_free (basename);
573 g_free (dirname);
574 }
575 /* try completing by appending libtool suffix */
576 if (!name)
577 {
578 name = g_strconcat (file_name, ".la", NULL);
579 if (!g_file_test (name, G_FILE_TEST_IS_REGULAR))
580 {
581 g_free (name);
582 name = NULL;
583 }
584 }
585 /* we can't access() the file, lets hope the platform backends finds
586 * it via library paths
587 */
588 if (!name)
589 {
590 gchar *dot = strrchr (file_name, '.');
591 gchar *slash = strrchr (file_name, G_DIR_SEPARATOR);
592
593 /* we make sure the name has a suffix using the deprecated
594 * G_MODULE_SUFFIX for backward-compat */
595 if (!dot || dot < slash)
596 name = g_strconcat (file_name, "." G_MODULE_SUFFIX, NULL);
597 else
598 name = g_strdup (file_name);
599 }
600
601 /* ok, try loading the module */
602 g_assert (name != NULL);
603
604 /* if it's a libtool archive, figure library file to load */
605 if (g_str_has_suffix (name, ".la")) /* libtool archive? */
606 {
607 gchar *real_name = parse_libtool_archive (name);
608
609 /* real_name might be NULL, but then module error is already set */
610 if (real_name)
611 {
612 g_free (name);
613 name = real_name;
614 }
615 }
616
617 handle = _g_module_open (name, (flags & G_MODULE_BIND_LAZY) != 0,
618 (flags & G_MODULE_BIND_LOCAL) != 0, error);
619 g_free (name);
620
621 if (handle)
622 {
623 gchar *saved_error;
624 GModuleCheckInit check_init;
625 const gchar *check_failed = NULL;
626
627 /* search the module list by handle, since file names are not unique */
628 module = g_module_find_by_handle (handle);
629 if (module)
630 {
631 _g_module_close (module->handle);
632 module->ref_count++;
633 g_module_set_error (NULL);
634
635 g_rec_mutex_unlock (&g_module_global_lock);
636 return module;
637 }
638
639 saved_error = g_strdup (g_module_error ());
640 g_module_set_error (NULL);
641
642 module = g_new (GModule, 1);
643 module->file_name = g_strdup (file_name);
644 module->handle = handle;
645 module->ref_count = 1;
646 module->is_resident = FALSE;
647 module->unload = NULL;
648 module->next = modules;
649 modules = module;
650
651 /* check initialization */
652 if (g_module_symbol (module, "g_module_check_init", (gpointer) &check_init) && check_init != NULL)
653 check_failed = check_init (module);
654
655 /* we don't call unload() if the initialization check failed. */
656 if (!check_failed)
657 g_module_symbol (module, "g_module_unload", (gpointer) &module->unload);
658
659 if (check_failed)
660 {
661 gchar *temp_error;
662
663 temp_error = g_strconcat ("GModule (", file_name, ") ",
664 "initialization check failed: ",
665 check_failed, NULL);
666 g_module_close (module);
667 module = NULL;
668 g_module_set_error (temp_error);
669 g_set_error_literal (error, G_MODULE_ERROR, G_MODULE_ERROR_CHECK_FAILED, temp_error);
670 g_free (temp_error);
671 }
672 else
673 g_module_set_error (saved_error);
674
675 g_free (saved_error);
676 }
677
678 if (module != NULL &&
679 (module_debug_flags & G_MODULE_DEBUG_RESIDENT_MODULES))
680 g_module_make_resident (module);
681
682 g_rec_mutex_unlock (&g_module_global_lock);
683 return module;
684 }
685
686 /**
687 * g_module_open:
688 * @file_name: (nullable): the name or path to the file containing the module,
689 * or %NULL to obtain a #GModule representing the main program itself
690 * @flags: the flags used for opening the module. This can be the
691 * logical OR of any of the #GModuleFlags.
692 *
693 * A thin wrapper function around g_module_open_full()
694 *
695 * Returns: a #GModule on success, or %NULL on failure
696 */
697 GModule *
698 g_module_open (const gchar *file_name,
699 GModuleFlags flags)
700 {
701 return g_module_open_full (file_name, flags, NULL);
702 }
703
704 /**
705 * g_module_close:
706 * @module: a #GModule to close
707 *
708 * Closes a module.
709 *
710 * Returns: %TRUE on success
711 */
712 gboolean
713 g_module_close (GModule *module)
714 {
715 SUPPORT_OR_RETURN (FALSE);
716
717 g_return_val_if_fail (module != NULL, FALSE);
718 g_return_val_if_fail (module->ref_count > 0, FALSE);
719
720 g_rec_mutex_lock (&g_module_global_lock);
721
722 module->ref_count--;
723
724 if (!module->ref_count && !module->is_resident && module->unload)
725 {
726 GModuleUnload unload;
727
728 unload = module->unload;
729 module->unload = NULL;
730 unload (module);
731 }
732
733 if (!module->ref_count && !module->is_resident)
734 {
735 GModule *last;
736 GModule *node;
737
738 last = NULL;
739
740 node = modules;
741 while (node)
742 {
743 if (node == module)
744 {
745 if (last)
746 last->next = node->next;
747 else
748 modules = node->next;
749 break;
750 }
751 last = node;
752 node = last->next;
753 }
754 module->next = NULL;
755
756 _g_module_close (module->handle);
757 g_free (module->file_name);
758 g_free (module);
759 }
760
761 g_rec_mutex_unlock (&g_module_global_lock);
762 return g_module_error() == NULL;
763 }
764
765 /**
766 * g_module_make_resident:
767 * @module: a #GModule to make permanently resident
768 *
769 * Ensures that a module will never be unloaded.
770 * Any future g_module_close() calls on the module will be ignored.
771 */
772 void
773 g_module_make_resident (GModule *module)
774 {
775 g_return_if_fail (module != NULL);
776
777 module->is_resident = TRUE;
778 }
779
780 /**
781 * g_module_error:
782 *
783 * Gets a string describing the last module error.
784 *
785 * Returns: a string describing the last module error
786 */
787 const gchar *
788 g_module_error (void)
789 {
790 return g_private_get (&module_error_private);
791 }
792
793 /**
794 * g_module_symbol:
795 * @module: a #GModule
796 * @symbol_name: the name of the symbol to find
797 * @symbol: (out): returns the pointer to the symbol value
798 *
799 * Gets a symbol pointer from a module, such as one exported
800 * by %G_MODULE_EXPORT. Note that a valid symbol can be %NULL.
801 *
802 * Returns: %TRUE on success
803 */
804 gboolean
805 g_module_symbol (GModule *module,
806 const gchar *symbol_name,
807 gpointer *symbol)
808 {
809 const gchar *module_error;
810
811 if (symbol)
812 *symbol = NULL;
813 SUPPORT_OR_RETURN (FALSE);
814
815 g_return_val_if_fail (module != NULL, FALSE);
816 g_return_val_if_fail (symbol_name != NULL, FALSE);
817 g_return_val_if_fail (symbol != NULL, FALSE);
818
819 g_rec_mutex_lock (&g_module_global_lock);
820
821 #ifdef G_MODULE_NEED_USCORE
822 {
823 gchar *name;
824
825 name = g_strconcat ("_", symbol_name, NULL);
826 *symbol = _g_module_symbol (module->handle, name);
827 g_free (name);
828 }
829 #else /* !G_MODULE_NEED_USCORE */
830 *symbol = _g_module_symbol (module->handle, symbol_name);
831 #endif /* !G_MODULE_NEED_USCORE */
832
833 module_error = g_module_error ();
834 if (module_error)
835 {
836 gchar *error;
837
838 error = g_strconcat ("'", symbol_name, "': ", module_error, NULL);
839 g_module_set_error (error);
840 g_free (error);
841 *symbol = NULL;
842 }
843
844 g_rec_mutex_unlock (&g_module_global_lock);
845 return !module_error;
846 }
847
848 /**
849 * g_module_name:
850 * @module: a #GModule
851 *
852 * Returns the filename that the module was opened with.
853 *
854 * If @module refers to the application itself, "main" is returned.
855 *
856 * Returns: (transfer none): the filename of the module
857 */
858 const gchar *
859 g_module_name (GModule *module)
860 {
861 g_return_val_if_fail (module != NULL, NULL);
862
863 if (module == main_module)
864 return "main";
865
866 return module->file_name;
867 }
868
869 /**
870 * g_module_build_path:
871 * @directory: (nullable): the directory where the module is. This can be
872 * %NULL or the empty string to indicate that the standard platform-specific
873 * directories will be used, though that is not recommended
874 * @module_name: the name of the module
875 *
876 * A portable way to build the filename of a module. The platform-specific
877 * prefix and suffix are added to the filename, if needed, and the result
878 * is added to the directory, using the correct separator character.
879 *
880 * The directory should specify the directory where the module can be found.
881 * It can be %NULL or an empty string to indicate that the module is in a
882 * standard platform-specific directory, though this is not recommended
883 * since the wrong module may be found.
884 *
885 * For example, calling g_module_build_path() on a Linux system with a
886 * @directory of `/lib` and a @module_name of "mylibrary" will return
887 * `/lib/libmylibrary.so`. On a Windows system, using `\Windows` as the
888 * directory it will return `\Windows\mylibrary.dll`.
889 *
890 * Returns: the complete path of the module, including the standard library
891 * prefix and suffix. This should be freed when no longer needed
892 *
893 * Deprecated: 2.76: Use g_module_open() instead with @module_name as the
894 * basename of the file_name argument. See %G_MODULE_SUFFIX for why.
895 */
896 gchar *
897 g_module_build_path (const gchar *directory,
898 const gchar *module_name)
899 {
900 g_return_val_if_fail (module_name != NULL, NULL);
901
902 return _g_module_build_path (directory, module_name);
903 }
904
905
906 #ifdef G_OS_WIN32
907
908 /* Binary compatibility versions. Not for newly compiled code. */
909
910 _GMODULE_EXTERN GModule * g_module_open_utf8 (const gchar *file_name,
911 GModuleFlags flags);
912
913 _GMODULE_EXTERN const gchar *g_module_name_utf8 (GModule *module);
914
915 GModule*
916 g_module_open_utf8 (const gchar *file_name,
917 GModuleFlags flags)
918 {
919 return g_module_open (file_name, flags);
920 }
921
922 const gchar *
923 g_module_name_utf8 (GModule *module)
924 {
925 return g_module_name (module);
926 }
927
928 #endif