1 files changed, 361 insertions, 0 deletions
diff --git a/src/util/plugin.c b/src/util/plugin.c
new file mode 100644
index 0000000..4e0385a
--- /dev/null
+++ b/src/util/plugin.c
@@ -0,0 +1,361 @@
+/*
+     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 <ltdl.h>
+#include "gnunet_common.h"
+#include "gnunet_os_lib.h"
+#include "gnunet_plugin_lib.h"
+
+#define LOG(kind,...) GNUNET_log_from (kind, "util", __VA_ARGS__)
+
+/**
+ * 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;
+};
+
+
+/**
+ * Have we been initialized?
+ */
+static int initialized;
+
+
+/**
+ * Libtool search path before we started.
+ */
+static char *old_dlsearchpath;
+
+
+/**
+ * List of plugins we have loaded.
+ */
+static struct PluginList *plugins;
+
+
+/**
+ * Setup libtool paths.
+ */
+static void
+plugin_init ()
+{
+  int err;
+  const char *opath;
+  char *path;
+  char *cpath;
+
+  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)
+    {
+      GNUNET_asprintf (&cpath, "%s:%s", opath, path);
+      lt_dlsetsearchpath (cpath);
+      GNUNET_free (path);
+      GNUNET_free (cpath);
+    }
+    else
+    {
+      lt_dlsetsearchpath (path);
+      GNUNET_free (path);
+    }
+  }
+}
+
+
+/**
+ * Shutdown libtool.
+ */
+static void
+plugin_fini ()
+{
+  lt_dlsetsearchpath (old_dlsearchpath);
+  if (old_dlsearchpath != NULL)
+  {
+    GNUNET_free (old_dlsearchpath);
+    old_dlsearchpath = NULL;
+  }
+  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)
+    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;
+}
+
+/**
+ * Test if a plugin exists.
+ *
+ * Note that the library must export a symbol called
+ * "library_name_init" for the test to succeed.
+ *
+ * @param library_name name of the plugin to test if it is installed
+ * @return GNUNET_YES if the plugin exists, GNUNET_NO if not
+ */
+int
+GNUNET_PLUGIN_test (const char *library_name)
+{
+  void *libhandle;
+  GNUNET_PLUGIN_Callback init;
+  struct PluginList plug;
+
+  if (!initialized)
+  {
+    initialized = GNUNET_YES;
+    plugin_init ();
+  }
+  libhandle = lt_dlopenext (library_name);
+  if (libhandle == NULL)
+    return GNUNET_NO;
+  plug.handle = libhandle;
+  plug.name = (char *) library_name;
+  init = resolve_function (&plug, "init");
+  if (init == NULL)
+  {
+    GNUNET_break (0);
+    lt_dlclose (libhandle);
+    return GNUNET_NO;
+  }
+  lt_dlclose (libhandle);
+  return GNUNET_YES;
+}
+
+
+/**
+ * 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;
+
+  if (!initialized)
+  {
+    initialized = GNUNET_YES;
+    plugin_init ();
+  }
+  libhandle = lt_dlopenext (library_name);
+  if (libhandle == NULL)
+  {
+    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))))
+  {
+    lt_dlclose (libhandle);
+    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);
+  if (plugins == NULL)
+  {
+    plugin_fini ();
+    initialized = GNUNET_NO;
+  }
+  return ret;
+}
+
+
+struct LoadAllContext
+{
+  const char *basename;
+  void *arg;
+  GNUNET_PLUGIN_LoaderCallback cb;
+  void *cb_cls;
+};
+
+
+static int
+find_libraries (void *cls, const char *filename)
+{
+  struct LoadAllContext *lac = cls;
+  const char *slashpos;
+  const char *libname;
+  char *basename;
+  char *dot;
+  void *lib_ret;
+  size_t n;
+
+  libname = filename;
+  while (NULL != (slashpos = strstr (libname, DIR_SEPARATOR_STR)))
+    libname = slashpos + 1;
+  n = strlen (libname);
+  if (0 != strncmp (lac->basename, libname, strlen (lac->basename)))
+    return GNUNET_OK;           /* wrong name */
+  if ((n > 3) && (0 == strcmp (&libname[n - 3], ".la")))
+    return GNUNET_OK;           /* .la file */
+  basename = GNUNET_strdup (libname);
+  if (NULL != (dot = strstr (basename, ".")))
+    *dot = '\0';
+  lib_ret = GNUNET_PLUGIN_load (basename, lac->arg);
+  if (NULL != lib_ret)
+    lac->cb (lac->cb_cls, basename, lib_ret);
+  GNUNET_free (basename);
+  return GNUNET_OK;
+}
+
+
+/**
+ * Load all compatible plugins with the given base name.
+ *
+ * Note that the library must export symbols called
+ * "basename_ANYTHING_init" and "basename_ANYTHING__done".  These will
+ * be called when the library is loaded and unloaded respectively.
+ *
+ * @param basename basename of the plugins to load
+ * @param arg argument to the plugin initialization function
+ * @param cb function to call for each plugin found
+ * @param cb_cls closure for 'cb'
+ */
+void
+GNUNET_PLUGIN_load_all (const char *basename, void *arg,
+                        GNUNET_PLUGIN_LoaderCallback cb, void *cb_cls)
+{
+  struct LoadAllContext lac;
+  char *path;
+
+  path = GNUNET_OS_installation_get_path (GNUNET_OS_IPK_LIBDIR);
+  if (path == NULL)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                _("Could not determine plugin installation path.\n"));
+    return;
+  }
+  lac.basename = basename;
+  lac.arg = arg;
+  lac.cb = cb;
+  lac.cb_cls = cb_cls;
+  GNUNET_DISK_directory_scan (path, &find_libraries, &lac);
+  GNUNET_free (path);
+}
+
+
+/* end of plugin.c */