2 * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
3 * 2000 Wim Taymans <wtay@chello.be>
5 * gstplugin.c: Plugin subsystem for loading elements, types, and libs
7 * This library is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Library General Public
9 * License as published by the Free Software Foundation; either
10 * version 2 of the License, or (at your option) any later version.
12 * This library is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Library General Public License for more details.
17 * You should have received a copy of the GNU Library General Public
18 * License along with this library; if not, write to the
19 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
20 * Boston, MA 02111-1307, USA.
25 * @short_description: Container for features loaded from a shared object module
26 * @see_also: #GstPluginFeature, #GstElementFactory
28 * GStreamer is extensible, so #GstElement instances can be loaded at runtime.
29 * A plugin system can provide one or more of the basic
30 * <application>GStreamer</application> #GstPluginFeature subclasses.
32 * A plugin should export a symbol <symbol>plugin_desc</symbol> that is a struct of type #GstPluginDesc.
33 * the plugin loader will check the version of the core library the plugin was
34 * linked against and will create a new #GstPlugin. It will then call the
35 * #GstPluginInitFunc function that was provided in the plugin_desc.
37 * Once you have a handle to a #GstPlugin (e.g. from the #GstRegistryPool), you
38 * can add any object that subclasses #GstPluginFeature.
40 * Use gst_plugin_find_feature() and gst_plugin_get_feature_list() to find
41 * features in a plugin.
43 * Usually plugins are always automaticlly loaded so you don't need to call
44 * gst_plugin_load() explicitly to bring it into memory. There are options to
45 * statically link plugins to an app or even use GStreamer without a plugin
46 * repository in which case gst_plugin_load() can be needed to bring the plugin
53 #include <sys/types.h>
64 #include "gst_private.h"
66 #include "gstplugin.h"
67 #include "gstversion.h"
69 #include "gstfilter.h"
70 #include "gstregistry.h"
71 #include "gstmacros.h"
74 #define GST_CAT_DEFAULT GST_CAT_PLUGIN_LOADING
76 static GModule *main_module = NULL;
77 static GList *_gst_plugin_static = NULL;
79 /* static variables for segfault handling of plugin loading */
80 static char *_gst_plugin_fault_handler_filename = NULL;
81 extern gboolean _gst_disable_segtrap; /* see gst.c */
84 static gboolean _gst_plugin_fault_handler_is_setup = FALSE;
87 /* list of valid licenses.
88 * One of these must be specified or the plugin won't be loaded
89 * Contact gstreamer-devel@lists.sourceforge.net if your license should be
92 * GPL: http://www.gnu.org/copyleft/gpl.html
93 * LGPL: http://www.gnu.org/copyleft/lesser.html
94 * QPL: http://www.trolltech.com/licenses/qpl.html
96 static gchar *valid_licenses[] = {
97 "LGPL", /* GNU Lesser General Public License */
98 "GPL", /* GNU General Public License */
99 "QPL", /* Trolltech Qt Public License */
100 "GPL/QPL", /* Combi-license of GPL + QPL */
101 GST_LICENSE_UNKNOWN, /* some other license */
105 static GstPlugin *gst_plugin_register_func (GstPlugin * plugin,
106 GModule * module, GstPluginDesc * desc);
108 gst_plugin_desc_copy (GstPluginDesc * dest, const GstPluginDesc * src);
109 static void gst_plugin_desc_free (GstPluginDesc * desc);
112 G_DEFINE_TYPE (GstPlugin, gst_plugin, GST_TYPE_OBJECT);
114 static GstObjectClass *parent_class = NULL;
117 gst_plugin_init (GstPlugin * plugin)
123 gst_plugin_finalize (GObject * object)
125 GstPlugin *plugin = GST_PLUGIN (object);
126 GstRegistry *registry = gst_registry_get_default ();
129 GST_DEBUG ("finalizing plugin %p", plugin);
130 for (g = registry->plugins; g; g = g->next) {
131 if (g->data == (gpointer) plugin) {
132 g_warning ("removing plugin that is still in registry");
135 g_free (plugin->filename);
136 g_free (plugin->basename);
137 gst_plugin_desc_free (&plugin->desc);
139 G_OBJECT_CLASS (parent_class)->finalize (object);
143 gst_plugin_class_init (GstPluginClass * klass)
145 parent_class = g_type_class_ref (GST_TYPE_OBJECT);
147 G_OBJECT_CLASS (klass)->finalize = GST_DEBUG_FUNCPTR (gst_plugin_finalize);
151 gst_plugin_error_quark (void)
153 static GQuark quark = 0;
156 quark = g_quark_from_static_string ("gst_plugin_error");
160 /* this function can be called in the GCC constructor extension, before
161 * the _gst_plugin_initialize() was called. In that case, we store the
162 * plugin description in a list to initialize it when we open the main
164 * When the main module is known, we can register the plugin right away.
167 _gst_plugin_register_static (GstPluginDesc * desc)
169 if (main_module == NULL) {
171 GST_LOG ("queueing static plugin \"%s\" for loading later on",
173 _gst_plugin_static = g_list_prepend (_gst_plugin_static, desc);
178 GST_LOG ("attempting to load static plugin \"%s\" now...", desc->name);
179 plugin = g_object_new (GST_TYPE_PLUGIN, NULL);
180 if (gst_plugin_register_func (plugin, main_module, desc)) {
182 GST_INFO ("loaded static plugin \"%s\"", desc->name);
183 gst_default_registry_add_plugin (plugin);
189 _gst_plugin_initialize (void)
191 main_module = g_module_open (NULL, G_MODULE_BIND_LAZY);
193 /* now register all static plugins */
194 g_list_foreach (_gst_plugin_static, (GFunc) _gst_plugin_register_static,
198 /* this function could be extended to check if the plugin license matches the
199 * applications license (would require the app to register its license somehow).
200 * We'll wait for someone who's interested in it to code it :)
203 gst_plugin_check_license (const gchar * license)
205 gchar **check_license = valid_licenses;
207 g_assert (check_license);
209 while (*check_license) {
210 if (strcmp (license, *check_license) == 0)
218 gst_plugin_check_version (gint major, gint minor)
220 /* return NULL if the major and minor version numbers are not compatible */
222 if (major != GST_VERSION_MAJOR || minor != GST_VERSION_MINOR)
229 gst_plugin_register_func (GstPlugin * plugin, GModule * module,
230 GstPluginDesc * desc)
232 if (!gst_plugin_check_version (desc->major_version, desc->minor_version)) {
234 GST_INFO ("plugin \"%s\" has incompatible version, not loading",
239 if (!desc->license || !desc->description || !desc->source ||
240 !desc->package || !desc->origin) {
242 GST_INFO ("plugin \"%s\" has incorrect GstPluginDesc, not loading",
247 if (!gst_plugin_check_license (desc->license)) {
249 GST_INFO ("plugin \"%s\" has invalid license \"%s\", not loading",
250 plugin->filename, desc->license);
255 GST_LOG ("plugin \"%s\" looks good", GST_STR_NULL (plugin->filename));
257 gst_plugin_desc_copy (&plugin->desc, desc);
259 if (!((desc->plugin_init) (plugin))) {
261 GST_INFO ("plugin \"%s\" failed to initialise", plugin->filename);
262 plugin->module = NULL;
267 GST_LOG ("plugin \"%s\" initialised", GST_STR_NULL (plugin->filename));
274 * _gst_plugin_fault_handler_restore:
275 * segfault handler restorer
278 _gst_plugin_fault_handler_restore (void)
280 struct sigaction action;
282 memset (&action, 0, sizeof (action));
283 action.sa_handler = SIG_DFL;
285 sigaction (SIGSEGV, &action, NULL);
289 * _gst_plugin_fault_handler_sighandler:
290 * segfault handler implementation
293 _gst_plugin_fault_handler_sighandler (int signum)
295 /* We need to restore the fault handler or we'll keep getting it */
296 _gst_plugin_fault_handler_restore ();
300 g_print ("\nERROR: ");
301 g_print ("Caught a segmentation fault while loading plugin file:\n");
302 g_print ("%s\n\n", _gst_plugin_fault_handler_filename);
303 g_print ("Please either:\n");
304 g_print ("- remove it and restart.\n");
305 g_print ("- run with --gst-disable-segtrap and debug.\n");
309 g_print ("Caught unhandled signal on plugin loading\n");
315 * _gst_plugin_fault_handler_setup:
316 * sets up the segfault handler
319 _gst_plugin_fault_handler_setup (void)
321 struct sigaction action;
323 /* if asked to leave segfaults alone, just return */
324 if (_gst_disable_segtrap)
327 if (_gst_plugin_fault_handler_is_setup)
330 memset (&action, 0, sizeof (action));
331 action.sa_handler = _gst_plugin_fault_handler_sighandler;
333 sigaction (SIGSEGV, &action, NULL);
337 _gst_plugin_fault_handler_restore (void)
342 _gst_plugin_fault_handler_setup (void)
347 static void _gst_plugin_fault_handler_setup ();
349 GStaticMutex gst_plugin_loading_mutex = G_STATIC_MUTEX_INIT;
352 * gst_plugin_load_file:
353 * @filename: the plugin filename to load
354 * @error: pointer to a NULL-valued GError
356 * Loads the given plugin and refs it. Caller needs to unref after use.
358 * Returns: a reference to the existing loaded GstPlugin, a reference to the
359 * newly-loaded GstPlugin, or NULL if an error occurred.
362 gst_plugin_load_file (const gchar * filename, GError ** error)
368 struct stat file_status;
369 GstRegistry *registry;
371 g_return_val_if_fail (filename != NULL, NULL);
373 registry = gst_registry_get_default ();
374 g_static_mutex_lock (&gst_plugin_loading_mutex);
376 plugin = gst_registry_lookup (registry, filename);
378 if (plugin->module) {
379 g_static_mutex_unlock (&gst_plugin_loading_mutex);
382 gst_object_unref (plugin);
387 GST_CAT_DEBUG (GST_CAT_PLUGIN_LOADING, "attempt to load plugin \"%s\"",
390 if (g_module_supported () == FALSE) {
391 GST_CAT_DEBUG (GST_CAT_PLUGIN_LOADING, "module loading not supported");
394 GST_PLUGIN_ERROR_MODULE, "Dynamic loading not supported");
398 if (stat (filename, &file_status)) {
399 GST_CAT_DEBUG (GST_CAT_PLUGIN_LOADING, "problem accessing file");
402 GST_PLUGIN_ERROR_MODULE, "Problem accessing file %s: %s\n", filename,
407 module = g_module_open (filename, G_MODULE_BIND_LOCAL);
408 if (module == NULL) {
409 GST_CAT_WARNING (GST_CAT_PLUGIN_LOADING, "module_open failed: %s",
412 GST_PLUGIN_ERROR, GST_PLUGIN_ERROR_MODULE, "Opening module failed");
416 plugin = g_object_new (GST_TYPE_PLUGIN, NULL);
418 plugin->module = module;
419 plugin->filename = strdup (filename);
420 plugin->basename = g_path_get_basename (filename);
421 plugin->file_mtime = file_status.st_mtime;
422 plugin->file_size = file_status.st_size;
424 ret = g_module_symbol (module, "gst_plugin_desc", &ptr);
426 GST_DEBUG ("Could not find plugin entry point in \"%s\"", filename);
429 GST_PLUGIN_ERROR_MODULE,
430 "File \"%s\" is not a GStreamer plugin", filename);
433 plugin->orig_desc = (GstPluginDesc *) ptr;
435 GST_LOG ("Plugin %p for file \"%s\" prepared, calling entry function...",
438 /* this is where we load the actual .so, so let's trap SIGSEGV */
439 _gst_plugin_fault_handler_setup ();
440 _gst_plugin_fault_handler_filename = plugin->filename;
442 GST_LOG ("Plugin %p for file \"%s\" prepared, registering...",
445 if (!gst_plugin_register_func (plugin, module, plugin->orig_desc)) {
446 /* remove signal handler */
447 _gst_plugin_fault_handler_restore ();
448 GST_DEBUG ("gst_plugin_register_func failed for plugin \"%s\"", filename);
452 GST_PLUGIN_ERROR_MODULE,
453 "File \"%s\" appears to be a GStreamer plugin, but it failed to initialize",
455 g_module_close (module);
459 /* remove signal handler */
460 _gst_plugin_fault_handler_restore ();
461 _gst_plugin_fault_handler_filename = NULL;
462 GST_INFO ("plugin \"%s\" loaded", plugin->filename);
464 gst_object_ref (plugin);
465 gst_default_registry_add_plugin (plugin);
467 g_static_mutex_unlock (&gst_plugin_loading_mutex);
471 gst_object_unref (plugin);
472 g_static_mutex_unlock (&gst_plugin_loading_mutex);
477 gst_plugin_desc_copy (GstPluginDesc * dest, const GstPluginDesc * src)
479 dest->major_version = src->major_version;
480 dest->minor_version = src->minor_version;
481 dest->name = g_strdup (src->name);
482 dest->description = g_strdup (src->description);
483 dest->plugin_init = src->plugin_init;
484 dest->version = g_strdup (src->version);
485 dest->license = g_strdup (src->license);
486 dest->source = g_strdup (src->source);
487 dest->package = g_strdup (src->package);
488 dest->origin = g_strdup (src->origin);
493 gst_plugin_desc_free (GstPluginDesc * desc)
496 g_free (desc->description);
497 g_free (desc->version);
498 g_free (desc->license);
499 g_free (desc->source);
500 g_free (desc->package);
501 g_free (desc->origin);
503 memset (desc, 0, sizeof (GstPluginDesc));
507 * gst_plugin_get_name:
508 * @plugin: plugin to get the name of
510 * Get the short name of the plugin
512 * Returns: the name of the plugin
515 gst_plugin_get_name (GstPlugin * plugin)
517 g_return_val_if_fail (plugin != NULL, NULL);
519 return plugin->desc.name;
523 * gst_plugin_get_description:
524 * @plugin: plugin to get long name of
526 * Get the long descriptive name of the plugin
528 * Returns: the long name of the plugin
530 G_CONST_RETURN gchar *
531 gst_plugin_get_description (GstPlugin * plugin)
533 g_return_val_if_fail (plugin != NULL, NULL);
535 return plugin->desc.description;
539 * gst_plugin_get_filename:
540 * @plugin: plugin to get the filename of
542 * get the filename of the plugin
544 * Returns: the filename of the plugin
546 G_CONST_RETURN gchar *
547 gst_plugin_get_filename (GstPlugin * plugin)
549 g_return_val_if_fail (plugin != NULL, NULL);
551 return plugin->filename;
555 * gst_plugin_get_version:
556 * @plugin: plugin to get the version of
558 * get the version of the plugin
560 * Returns: the version of the plugin
562 G_CONST_RETURN gchar *
563 gst_plugin_get_version (GstPlugin * plugin)
565 g_return_val_if_fail (plugin != NULL, NULL);
567 return plugin->desc.version;
571 * gst_plugin_get_license:
572 * @plugin: plugin to get the license of
574 * get the license of the plugin
576 * Returns: the license of the plugin
578 G_CONST_RETURN gchar *
579 gst_plugin_get_license (GstPlugin * plugin)
581 g_return_val_if_fail (plugin != NULL, NULL);
583 return plugin->desc.license;
587 * gst_plugin_get_source:
588 * @plugin: plugin to get the source of
590 * get the source module the plugin belongs to.
592 * Returns: the source of the plugin
594 G_CONST_RETURN gchar *
595 gst_plugin_get_source (GstPlugin * plugin)
597 g_return_val_if_fail (plugin != NULL, NULL);
599 return plugin->desc.source;
603 * gst_plugin_get_package:
604 * @plugin: plugin to get the package of
606 * get the package the plugin belongs to.
608 * Returns: the package of the plugin
610 G_CONST_RETURN gchar *
611 gst_plugin_get_package (GstPlugin * plugin)
613 g_return_val_if_fail (plugin != NULL, NULL);
615 return plugin->desc.package;
619 * gst_plugin_get_origin:
620 * @plugin: plugin to get the origin of
622 * get the URL where the plugin comes from
624 * Returns: the origin of the plugin
626 G_CONST_RETURN gchar *
627 gst_plugin_get_origin (GstPlugin * plugin)
629 g_return_val_if_fail (plugin != NULL, NULL);
631 return plugin->desc.origin;
635 * gst_plugin_get_module:
636 * @plugin: plugin to query
638 * Gets the #GModule of the plugin. If the plugin isn't loaded yet, NULL is
641 * Returns: module belonging to the plugin or NULL if the plugin isn't
645 gst_plugin_get_module (GstPlugin * plugin)
647 g_return_val_if_fail (plugin != NULL, NULL);
649 return plugin->module;
653 * gst_plugin_is_loaded:
654 * @plugin: plugin to query
656 * queries if the plugin is loaded into memory
658 * Returns: TRUE is loaded, FALSE otherwise
661 gst_plugin_is_loaded (GstPlugin * plugin)
663 g_return_val_if_fail (plugin != NULL, FALSE);
665 return (plugin->module != NULL || plugin->filename == NULL);
670 * gst_plugin_feature_list:
671 * @plugin: plugin to query
672 * @filter: the filter to use
673 * @first: only return first match
674 * @user_data: user data passed to the filter function
676 * Runs a filter against all plugin features and returns a GList with
677 * the results. If the first flag is set, only the first match is
678 * returned (as a list with a single object).
680 * Returns: a GList of features, g_list_free after use.
683 gst_plugin_feature_filter (GstPlugin * plugin,
684 GstPluginFeatureFilter filter, gboolean first, gpointer user_data)
689 list = gst_filter_run (plugin->features, (GstFilterFunc) filter, first,
691 for (g = list; g; g = g->next) {
692 gst_object_ref (plugin);
700 GstPluginFeatureFilter filter;
708 _feature_filter (GstPlugin * plugin, gpointer user_data)
711 FeatureFilterData *data = (FeatureFilterData *) user_data;
713 result = gst_plugin_feature_filter (plugin, data->filter, data->first,
716 data->result = g_list_concat (data->result, result);
723 * gst_plugin_list_feature_filter:
724 * @list: a #GList of plugins to query
725 * @filter: the filter function to use
726 * @first: only return first match
727 * @user_data: user data passed to the filter function
729 * Runs a filter against all plugin features of the plugins in the given
730 * list and returns a GList with the results.
731 * If the first flag is set, only the first match is
732 * returned (as a list with a single object).
734 * Returns: a GList of features, g_list_free after use.
737 gst_plugin_list_feature_filter (GList * list,
738 GstPluginFeatureFilter filter, gboolean first, gpointer user_data)
740 FeatureFilterData data;
743 data.filter = filter;
745 data.user_data = user_data;
748 result = gst_filter_run (list, (GstFilterFunc) _feature_filter, first, &data);
749 g_list_free (result);
756 * gst_plugin_name_filter:
757 * @plugin: the plugin to check
758 * @name: the name of the plugin
760 * A standard filter that returns TRUE when the plugin is of the
763 * Returns: TRUE if the plugin is of the given name.
766 gst_plugin_name_filter (GstPlugin * plugin, const gchar * name)
768 return (plugin->desc.name && !strcmp (plugin->desc.name, name));
773 * gst_plugin_find_feature:
774 * @plugin: plugin to get the feature from
775 * @name: The name of the feature to find
776 * @type: The type of the feature to find
778 * Find a feature of the given name and type in the given plugin.
780 * Returns: a GstPluginFeature or NULL if the feature was not found.
783 gst_plugin_find_feature (GstPlugin * plugin, const gchar * name, GType type)
786 GstPluginFeature *result = NULL;
787 GstTypeNameData data;
789 g_return_val_if_fail (name != NULL, NULL);
794 walk = gst_filter_run (plugin->features,
795 (GstFilterFunc) gst_plugin_feature_type_name_filter, TRUE, &data);
798 result = GST_PLUGIN_FEATURE (walk->data);
800 gst_object_ref (result);
801 gst_plugin_feature_list_free (walk);
810 gst_plugin_feature_name_filter (GstPluginFeature * feature, const gchar * name)
812 return !strcmp (name, GST_PLUGIN_FEATURE_NAME (feature));
818 * gst_plugin_find_feature_by_name:
819 * @plugin: plugin to get the feature from
820 * @name: The name of the feature to find
822 * Find a feature of the given name in the given plugin.
824 * Returns: a GstPluginFeature or NULL if the feature was not found.
827 gst_plugin_find_feature_by_name (GstPlugin * plugin, const gchar * name)
830 GstPluginFeature *result = NULL;
832 g_return_val_if_fail (name != NULL, NULL);
834 walk = gst_filter_run (plugin->features,
835 (GstFilterFunc) gst_plugin_feature_name_filter, TRUE, (void *) name);
838 result = GST_PLUGIN_FEATURE (walk->data);
840 gst_object_ref (result);
841 gst_plugin_feature_list_free (walk);
849 * gst_plugin_load_by_name:
850 * @name: name of plugin to load
852 * Load the named plugin. Refs the plugin.
854 * Returns: A reference to a loaded plugin, or NULL on error.
857 gst_plugin_load_by_name (const gchar * name)
859 GstPlugin *plugin, *newplugin;
860 GError *error = NULL;
862 GST_DEBUG ("looking up plugin %s in default registry", name);
863 plugin = gst_registry_find_plugin (gst_registry_get_default (), name);
865 GST_DEBUG ("loading plugin %s from file %s", name, plugin->filename);
866 newplugin = gst_plugin_load_file (plugin->filename, &error);
867 gst_object_unref (plugin);
870 GST_WARNING ("load_plugin error: %s\n", error->message);
871 g_error_free (error);
874 /* newplugin was reffed by load_file */
878 GST_DEBUG ("Could not find plugin %s in registry", name);
884 * @plugin: plugin to load
886 * Loads @plugin. Note that the *return value* is the loaded plugin; @plugin is
887 * untouched. The normal use pattern of this function goes like this:
890 * GstPlugin *loaded_plugin;
891 * loaded_plugin = gst_plugin_load (plugin);
893 * // presumably, we're no longer interested in the potentially-unloaded plugin
894 * gst_object_unref (plugin);
895 * plugin = loaded_plugin;
898 * Returns: A reference to a loaded plugin, or NULL on error.
901 gst_plugin_load (GstPlugin * plugin)
903 GError *error = NULL;
904 GstPlugin *newplugin;
906 if (gst_plugin_is_loaded (plugin)) {
910 if (!(newplugin = gst_plugin_load_file (plugin->filename, &error)))
917 GST_WARNING ("load_plugin error: %s\n", error->message);
918 g_error_free (error);
924 * gst_plugin_list_free:
925 * @list: list of #GstPlugin
927 * Unrefs each member of @list, then frees the list.
930 gst_plugin_list_free (GList * list)
934 for (g = list; g; g = g->next) {
935 gst_object_unref (GST_PLUGIN (g->data));