From d28fe1c4f463314a79f0a71f6f8a01db53e37253 Mon Sep 17 00:00:00 2001
From: jgeboski <jgeboski@gmail.com>
Date: Sun, 15 May 2016 14:17:34 -0400
Subject: Implemented plugin information for external plugins

As of now, bitlbee will load any plugin regardless of the ABI it was
built against. This is really problematic when structures or symbols
are changed within bitlbee. This often leads to the plugin not loading
or the plugin acting in an undefined way. Typically a simple rebuild of
the plugin will resolve such issues, but many users have no idea that
this is required after they have updated bitlbee.

Furthermore, it is often times impossible to determine the version of
a plugin, without relying on the package manager of the system. This is
quite a problem when users are reporting bugs for external plugins, and
they have no idea what version of the plugin they are running. This is
also an opportunity to provide additional metadata for each plugin that
can then be displayed to the user.

Solving these issues is done by adding a new required function to each
plugin. The init_plugin_info() function must now be implemented along
with the init_plugin() function. This function then returns a static
structure, which retains all of the metadata for the plugin. Then this
is used by bitlbee to check the ABI version and provide information to
the user.

The introduction of the new function is required as bitlbee needs to
obtain the ABI version before calling init_plugin().

The boiler-plate implementation of init_plugin_info():

  #ifdef BITLBEE_ABI_VERSION_CODE
  struct plugin_info *init_plugin_info(void)
  {
      static struct plugin_info info = {
          BITLBEE_ABI_VERSION_CODE,            /* Required */
          "plugin-name",                       /* Required */
          "1.3.3.7",                           /* Required */
          "A short description of the plugin", /* Optional */
          "First Last <alias@domain.tld>",     /* Optional */
          "http://www.domain.tld"              /* Optional */
      };

      return &info;
  }
  #endif

The example wraps the function declaration in an if block for backwards
compatibility with older bitlbee versions.

Displaying the plugin metadata is done via the newly added "plugins"
command, which simply dumps formatted data to the root channel.
---
 protocols/nogaim.c | 67 +++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 66 insertions(+), 1 deletion(-)

(limited to 'protocols/nogaim.c')

diff --git a/protocols/nogaim.c b/protocols/nogaim.c
index c9cbb033..9ed3b64b 100644
--- a/protocols/nogaim.c
+++ b/protocols/nogaim.c
@@ -39,24 +39,84 @@
 GSList *connections;
 
 #ifdef WITH_PLUGINS
+GList *plugins = NULL;
+
+static gint pluginscmp(gconstpointer a, gconstpointer b, gpointer data)
+{
+	const struct plugin_info *ia = a;
+	const struct plugin_info *ib = b;
+
+	return g_strcasecmp(ia->name, ib->name);
+}
+
 gboolean load_plugin(char *path)
 {
+	GList *l;
+	struct plugin_info *i;
+	struct plugin_info *info;
+	struct plugin_info * (*info_function) (void) = NULL;
 	void (*init_function) (void);
 
 	GModule *mod = g_module_open(path, G_MODULE_BIND_LAZY);
+	gboolean loaded = FALSE;
 
 	if (!mod) {
 		log_message(LOGLVL_ERROR, "Error loading plugin `%s': %s\n", path, g_module_error());
 		return FALSE;
 	}
 
+	if (g_module_symbol(mod, "init_plugin_info", (gpointer *) &info_function)) {
+		info = info_function();
+
+		if (info->abiver != BITLBEE_ABI_VERSION_CODE) {
+			log_message(LOGLVL_ERROR,
+				    "`%s' uses ABI %u but %u is required\n",
+				    path, info->abiver,
+				    BITLBEE_ABI_VERSION_CODE);
+			g_module_close(mod);
+			return FALSE;
+		}
+
+		if (!info->name || !info->version) {
+			log_message(LOGLVL_ERROR,
+				    "Name or version missing from the "
+				    "plugin info in `%s'\n", path);
+			g_module_close(mod);
+			return FALSE;
+		}
+
+		for (l = plugins; l; l = l->next) {
+			i = l->data;
+
+			if (g_strcasecmp(i->name, info->name) == 0) {
+				loaded = TRUE;
+				break;
+			}
+		}
+
+		if (loaded) {
+			log_message(LOGLVL_WARNING,
+				    "%s plugin already loaded\n",
+				    info->name);
+			g_module_close(mod);
+			return FALSE;
+		}
+	} else {
+		log_message(LOGLVL_WARNING, "Can't find function `init_plugin_info' in `%s'\n", path);
+	}
+
 	if (!g_module_symbol(mod, "init_plugin", (gpointer *) &init_function)) {
 		log_message(LOGLVL_WARNING, "Can't find function `init_plugin' in `%s'\n", path);
+		g_module_close(mod);
 		return FALSE;
 	}
 
-	init_function();
+	if (info_function) {
+		plugins = g_list_insert_sorted_with_data(plugins, info,
+		                                         pluginscmp, NULL);
+	}
 
+	init_function();
 	return TRUE;
 }
 
@@ -86,6 +146,11 @@ void load_plugins(void)
 		g_dir_close(dir);
 	}
 }
+
+GList *get_plugins()
+{
+	return plugins;
+}
 #endif
 
 GList *protocols = NULL;
-- 
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