plugins/plugin.c

   1 /*
   2  * plugin.c
   3  *
   4  * Babeltrace Plugin
   5  *
   6  * Copyright 2015 Jérémie Galarneau <jeremie.galarneau@efficios.com>
   7  *
   8  * Author: Jérémie Galarneau <jeremie.galarneau@efficios.com>
   9  *
  10  * Permission is hereby granted, free of charge, to any person obtaining a copy
  11  * of this software and associated documentation files (the "Software"), to deal
  12  * in the Software without restriction, including without limitation the rights
  13  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  14  * copies of the Software, and to permit persons to whom the Software is
  15  * furnished to do so, subject to the following conditions:
  16  *
  17  * The above copyright notice and this permission notice shall be included in
  18  * all copies or substantial portions of the Software.
  19  *
  20  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  21  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  23  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  24  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  25  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  26  * SOFTWARE.
  27  */
  28
  29 #include <babeltrace/compiler.h>
  30 #include <babeltrace/ref.h>
  31 #include <babeltrace/plugin/plugin-internal.h>
  32 #include <glib.h>
  33
  34 #define PLUGIN_SYMBOL_NAME      "__bt_plugin_name"
  35 #define PLUGIN_SYMBOL_AUTHOR    "__bt_plugin_author"
  36 #define PLUGIN_SYMBOL_LICENSE   "__bt_plugin_license"
  37 #define PLUGIN_SYMBOL_INIT      "__bt_plugin_init"
  38 #define PLUGIN_SYMBOL_EXIT      "__bt_plugin_exit"
  39
  40 static
  41 void bt_plugin_destroy(struct bt_object *obj)
  42 {
  43         struct bt_plugin *plugin;
  44
  45         assert(obj);
  46         plugin = container_of(obj, struct bt_plugin, base);
  47
  48         if (plugin->module) {
  49                 if (!g_module_close(plugin->module)) {
  50                         printf_error("Module close error: %s",
  51                                 g_module_error());
  52
  53                 }
  54         }
  55         g_free(plugin);
  56 }
  57
  58 BT_HIDDEN
  59 struct bt_plugin *bt_plugin_create(GModule *module)
  60 {
  61         struct bt_plugin *plugin = NULL;
  62
  63         if (!module) {
  64                 goto error;
  65         }
  66
  67         plugin = g_new0(struct bt_plugin, 1);
  68         if (!plugin) {
  69                 goto error;
  70         }
  71
  72         bt_object_init(plugin, bt_plugin_destroy);
  73         if (!g_module_symbol(module, PLUGIN_SYMBOL_NAME,
  74                 (gpointer *) &plugin->name))
  75         {
  76                 printf_error("Unable to resolve plugin symbol %s from %s",
  77                         PLUGIN_SYMBOL_NAME, g_module_name(module));
  78                 goto error;
  79         }
  80
  81         printf("Loaded plugin with name %s\n", plugin->name);
  82         if (!g_module_symbol(module, PLUGIN_SYMBOL_LICENSE,
  83                 (gpointer *) &plugin->license))
  84         {
  85                 printf_error("Unable to resolve plugin symbol %s from %s",
  86                         PLUGIN_SYMBOL_LICENSE, g_module_name(module));
  87                 goto error;
  88         }
  89         if (!g_module_symbol(module, PLUGIN_SYMBOL_INIT,
  90                 (gpointer *) &plugin->init))
  91         {
  92                 printf_error("Unable to resolve plugin symbol %s from %s",
  93                         PLUGIN_SYMBOL_INIT, g_module_name(module));
  94                 goto error;
  95         }
  96
  97         /* Optional symbols */
  98         g_module_symbol(module, PLUGIN_SYMBOL_EXIT, (gpointer *) &plugin->exit);
  99         g_module_symbol(module, PLUGIN_SYMBOL_AUTHOR,
 100                 (gpointer *) &plugin->author);
 101
 102         return plugin;
 103 error:
 104         BT_PUT(plugin);
 105         return plugin;
 106 }
 107
 108 BT_HIDDEN
 109 enum bt_component_status bt_plugin_register_component_classes(
 110                 struct bt_plugin *plugin, struct bt_component_factory *factory)
 111 {
 112         assert(plugin && factory);
 113         return plugin->init(factory);
 114 }