lib/plugin-system/plugin.c

   1 /*
   2  * plugin.c
   3  *
   4  * Babeltrace Plugin
   5  *
   6  * Copyright 2016 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 #define PLUGIN_SYMBOL_DESCRIPTION       "__bt_plugin_description"
  40
  41 static
  42 void bt_plugin_destroy(struct bt_object *obj)
  43 {
  44         struct bt_plugin *plugin;
  45
  46         assert(obj);
  47         plugin = container_of(obj, struct bt_plugin, base);
  48
  49         if (plugin->exit) {
  50                 plugin->exit();
  51         }
  52
  53         if (plugin->module) {
  54                 if (!g_module_close(plugin->module)) {
  55                                 printf_error("Module close error: %s",
  56                                         g_module_error());
  57                 }
  58         }
  59
  60         g_string_free(plugin->path, TRUE);
  61         g_free(plugin);
  62 }
  63
  64 BT_HIDDEN
  65 struct bt_plugin *bt_plugin_create(GModule *module, const char *path)
  66 {
  67         struct bt_plugin *plugin = NULL;
  68         gpointer symbol = NULL;
  69
  70         if (!module || !path) {
  71                 goto error;
  72         }
  73
  74         plugin = g_new0(struct bt_plugin, 1);
  75         if (!plugin) {
  76                 goto error;
  77         }
  78
  79         bt_object_init(plugin, bt_plugin_destroy);
  80         plugin->path = g_string_new(path);
  81         if (!plugin->path) {
  82                 goto error;
  83         }
  84
  85         if (!g_module_symbol(module, PLUGIN_SYMBOL_NAME,
  86                         (gpointer *) &plugin->name)) {
  87                 printf_error("Unable to resolve plugin symbol %s from %s",
  88                                 PLUGIN_SYMBOL_NAME, g_module_name(module));
  89                 goto error;
  90         }
  91
  92         if (!g_module_symbol(module, PLUGIN_SYMBOL_LICENSE,
  93                         (gpointer *) &plugin->license)) {
  94                 printf_error("Unable to resolve plugin symbol %s from %s",
  95                                 PLUGIN_SYMBOL_LICENSE, g_module_name(module));
  96                 goto error;
  97         }
  98         if (!g_module_symbol(module, PLUGIN_SYMBOL_INIT, &symbol)) {
  99                 printf_error("Unable to resolve plugin symbol %s from %s",
 100                                 PLUGIN_SYMBOL_INIT, g_module_name(module));
 101                 goto error;
 102         } else {
 103                 plugin->init = *((bt_plugin_init_func *) symbol);
 104                 if (!plugin->init) {
 105                         printf_error("NULL %s symbol target",
 106                                         PLUGIN_SYMBOL_INIT);
 107                         goto error;
 108                 }
 109         }
 110
 111         /* Optional */
 112         if (g_module_symbol(module, PLUGIN_SYMBOL_EXIT,
 113                         (gpointer *) &symbol)) {
 114                 plugin->exit = *((bt_plugin_exit_func *) symbol);
 115         }
 116         g_module_symbol(module, PLUGIN_SYMBOL_AUTHOR,
 117                         (gpointer *) &plugin->author);
 118         g_module_symbol(module, PLUGIN_SYMBOL_DESCRIPTION,
 119                         (gpointer *) &plugin->description);
 120
 121         return plugin;
 122 error:
 123         BT_PUT(plugin);
 124         return plugin;
 125 }
 126
 127 BT_HIDDEN
 128 enum bt_component_status bt_plugin_register_component_classes(
 129                 struct bt_plugin *plugin, struct bt_component_factory *factory)
 130 {
 131         assert(plugin && factory);
 132         return plugin->init(factory);
 133 }
 134
 135 const char *bt_plugin_get_name(struct bt_plugin *plugin)
 136 {
 137         return plugin ? plugin->name : NULL;
 138 }
 139
 140 const char *bt_plugin_get_author(struct bt_plugin *plugin)
 141 {
 142         return plugin ? plugin->author : NULL;
 143 }
 144
 145 const char *bt_plugin_get_license(struct bt_plugin *plugin)
 146 {
 147         return plugin ? plugin->license : NULL;
 148 }
 149
 150 const char *bt_plugin_get_path(struct bt_plugin *plugin)
 151 {
 152         return plugin ? plugin->path->str : NULL;
 153 }
 154
 155 const char *bt_plugin_get_description(struct bt_plugin *plugin)
 156 {
 157         return plugin ? plugin->description : NULL;
 158 }