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/plugin/plugin-internal.h>
  31 #include <glib.h>
  32
  33 #define PLUGIN_SYMBOL_NAME      "__bt_plugin_name"
  34 #define PLUGIN_SYMBOL_AUTHOR    "__bt_plugin_author"
  35 #define PLUGIN_SYMBOL_LICENSE   "__bt_plugin_license"
  36 #define PLUGIN_SYMBOL_INIT      "__bt_plugin_init"
  37 #define PLUGIN_SYMBOL_EXIT      "__bt_plugin_exit"
  38
  39 static
  40 void bt_plugin_destroy(struct bt_ref *ref)
  41 {
  42         struct bt_plugin *plugin;
  43
  44         assert(ref);
  45         plugin = container_of(ref, struct bt_plugin, ref);
  46         if (plugin->module) {
  47                 if (!g_module_close(plugin->module)) {
  48                         printf_error("Module close error: %s",
  49                                 g_module_error());
  50
  51                 }
  52         }
  53         g_free(plugin);
  54 }
  55
  56 BT_HIDDEN
  57 struct bt_plugin *bt_plugin_create(GModule *module)
  58 {
  59         struct bt_plugin *plugin = NULL;
  60
  61         if (!module) {
  62                 goto error;
  63         }
  64
  65         plugin = g_new0(struct bt_plugin, 1);
  66         if (!plugin) {
  67                 goto error;
  68         }
  69
  70         bt_ref_init(&plugin->ref, bt_plugin_destroy);
  71         if (!g_module_symbol(module, PLUGIN_SYMBOL_NAME,
  72                 (gpointer *) &plugin->name))
  73         {
  74                 printf_error("Unable to resolve plugin symbol %s from %s",
  75                         PLUGIN_SYMBOL_NAME, g_module_name(module));
  76                 goto error;
  77         }
  78         if (!g_module_symbol(module, PLUGIN_SYMBOL_LICENSE,
  79                 (gpointer *) &plugin->license))
  80         {
  81                 printf_error("Unable to resolve plugin symbol %s from %s",
  82                         PLUGIN_SYMBOL_LICENSE, g_module_name(module));
  83                 goto error;
  84         }
  85         if (!g_module_symbol(module, PLUGIN_SYMBOL_INIT,
  86                 (gpointer *) &plugin->init))
  87         {
  88                 printf_error("Unable to resolve plugin symbol %s from %s",
  89                         PLUGIN_SYMBOL_INIT, g_module_name(module));
  90                 goto error;
  91         }
  92
  93         /* Optional symbols */
  94         g_module_symbol(module, PLUGIN_SYMBOL_EXIT, (gpointer *) &plugin->exit);
  95         g_module_symbol(module, PLUGIN_SYMBOL_AUTHOR,
  96                 (gpointer *) &plugin->author);
  97
  98         return plugin;
  99 error:
 100         bt_plugin_put(plugin);
 101         return NULL;
 102 }
 103
 104 BT_HIDDEN
 105 enum bt_component_status bt_plugin_register_component_classes(
 106                 struct bt_plugin *plugin, struct bt_component_factory *factory)
 107 {
 108         assert(plugin && factory);
 109         return plugin->init(factory);
 110 }
 111
 112 BT_HIDDEN
 113 void bt_plugin_get(struct bt_plugin *plugin)
 114 {
 115         if (!plugin) {
 116                 return;
 117         }
 118
 119         bt_ref_get(&plugin->ref);
 120 }
 121
 122 BT_HIDDEN
 123 void bt_plugin_put(struct bt_plugin *plugin)
 124 {
 125         if (!plugin) {
 126                 return;
 127         }
 128
 129         bt_ref_put(&plugin->ref);
 130 }