1 files changed, 243 insertions, 0 deletions

diff --git a/src/util/plugin.c b/src/util/plugin.c
new file mode 100644
index 000000000..d26a343c7
--- /dev/null
+++ b/src/util/plugin.c
@@ -0,0 +1,243 @@
+/*
+     This file is part of GNUnet
+     (C) 2002, 2003, 2004, 2005, 2006, 2009 Christian Grothoff (and other contributing authors)
+
+     GNUnet is free software; you can redistribute it and/or modify
+     it under the terms of the GNU General Public License as published
+     by the Free Software Foundation; either version 2, or (at your
+     option) any later version.
+
+     GNUnet is distributed in the hope that it will be useful, but
+     WITHOUT ANY WARRANTY; without even the implied warranty of
+     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+     General Public License for more details.
+
+     You should have received a copy of the GNU General Public License
+     along with GNUnet; see the file COPYING.  If not, write to the
+     Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+     Boston, MA 02111-1307, USA.
+*/
+
+/**
+ * @file util/plugin.c
+ * @brief Methods to access plugins
+ * @author Christian Grothoff
+ */
+
+#include "platform.h"
+#include <libltdl/ltdl.h>
+#include "gnunet_common.h"
+#include "gnunet_os_lib.h"
+#include "gnunet_plugin_lib.h"
+
+/**
+ * Linked list of active plugins.
+ */
+struct PluginList
+{
+  /**
+   * This is a linked list.
+   */
+  struct PluginList *next;
+
+  /**
+   * Name of the library.
+   */
+  char *name;
+
+  /**
+   * System handle.
+   */
+  void *handle;
+};
+
+
+/**
+ * Libtool search path before we started.
+ */
+static char *old_dlsearchpath;
+
+
+/**
+ * List of plugins we have loaded.
+ */
+static struct PluginList *plugins;
+
+
+/**
+ * Setup libtool paths.
+ */
+void __attribute__ ((constructor)) GNUNET_PLUGIN_init ()
+{
+  int err;
+  const char *opath;
+  char *path;
+  char *cpath;
+
+#ifdef MINGW
+  InitWinEnv (NULL);
+#endif
+
+  err = lt_dlinit ();
+  if (err > 0)
+    {
+      fprintf (stderr,
+               _("Initialization of plugin mechanism failed: %s!\n"),
+               lt_dlerror ());
+      return;
+    }
+  opath = lt_dlgetsearchpath ();
+  if (opath != NULL)
+    old_dlsearchpath = GNUNET_strdup (opath);
+  path = GNUNET_OS_installation_get_path (GNUNET_OS_IPK_LIBDIR);
+  if (path != NULL)
+    {
+      if (opath != NULL)
+        {
+          cpath = GNUNET_malloc (strlen (path) + strlen (opath) + 4);
+          strcpy (cpath, opath);
+          strcat (cpath, ":");
+          strcat (cpath, path);
+          lt_dlsetsearchpath (cpath);
+          GNUNET_free (path);
+          GNUNET_free (cpath);
+        }
+      else
+        {
+          lt_dlsetsearchpath (path);
+          GNUNET_free (path);
+        }
+    }
+}
+
+
+/**
+ * Shutdown libtool.
+ */
+void __attribute__ ((destructor)) GNUNET_PLUGIN_fini ()
+{
+  lt_dlsetsearchpath (old_dlsearchpath);
+  if (old_dlsearchpath != NULL)
+    {
+      GNUNET_free (old_dlsearchpath);
+      old_dlsearchpath = NULL;
+    }
+
+#ifdef MINGW
+  ShutdownWinEnv ();
+#endif
+
+  lt_dlexit ();
+}
+
+
+/**
+ * Lookup a function in the plugin.
+ */
+static GNUNET_PLUGIN_Callback
+resolve_function (struct PluginList *plug, const char *name)
+{
+  char *initName;
+  void *mptr;
+
+  GNUNET_asprintf (&initName, "_%s_%s", plug->name, name);
+  mptr = lt_dlsym (plug->handle, &initName[1]);
+  if (mptr == NULL)
+    mptr = lt_dlsym (plug->handle, initName);
+  if (mptr == NULL)
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                _("`%s' failed to resolve method '%s' with error: %s\n"),
+                "lt_dlsym", &initName[1], lt_dlerror ());
+  GNUNET_free (initName);
+  return mptr;
+}
+
+
+/**
+ * Setup plugin (runs the "init" callback and returns whatever "init"
+ * returned).  If "init" returns NULL, the plugin is unloaded.
+ *
+ * Note that the library must export symbols called
+ * "library_name_init" and "library_name_done".  These will be called
+ * when the library is loaded and unloaded respectively.
+ *
+ * @param library_name name of the plugin to load
+ * @param arg argument to the plugin initialization function
+ * @return whatever the initialization function returned
+ */
+void *
+GNUNET_PLUGIN_load (const char *library_name, void *arg)
+{
+  void *libhandle;
+  struct PluginList *plug;
+  GNUNET_PLUGIN_Callback init;
+  void *ret;
+
+  libhandle = lt_dlopenext (library_name);
+  if (libhandle == NULL)
+    {
+      GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                  _("`%s' failed for library `%s' with error: %s\n"),
+                  "lt_dlopenext", library_name, lt_dlerror ());
+      return NULL;
+    }
+  plug = GNUNET_malloc (sizeof (struct PluginList));
+  plug->handle = libhandle;
+  plug->name = GNUNET_strdup (library_name);
+  plug->next = plugins;
+  plugins = plug;
+  init = resolve_function (plug, "init");
+  if ((init == NULL) || (NULL == (ret = init (arg))))
+    {
+      GNUNET_free (plug->name);
+      plugins = plug->next;
+      GNUNET_free (plug);
+      return NULL;
+    }
+  return ret;
+}
+
+
+/**
+ * Unload plugin (runs the "done" callback and returns whatever "done"
+ * returned).  The plugin is then unloaded.
+ *
+ * @param library_name name of the plugin to unload
+ * @param arg argument to the plugin shutdown function
+ * @return whatever the shutdown function returned
+ */
+void *
+GNUNET_PLUGIN_unload (const char *library_name, void *arg)
+{
+  struct PluginList *pos;
+  struct PluginList *prev;
+  GNUNET_PLUGIN_Callback done;
+  void *ret;
+
+  prev = NULL;
+  pos = plugins;
+  while ((pos != NULL) && (0 != strcmp (pos->name, library_name)))
+    {
+      prev = pos;
+      pos = pos->next;
+    }
+  if (pos == NULL)
+    return NULL;
+
+  done = resolve_function (pos, "done");
+  ret = NULL;
+  if (done != NULL)
+    ret = done (arg);
+  if (prev == NULL)
+    plugins = pos->next;
+  else
+    prev->next = pos->next;
+  // lt_dlclose (pos->handle);
+  GNUNET_free (pos->name);
+  GNUNET_free (pos);
+  return ret;
+}
+
+
+
+/* end of plugin.c */