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