greeter: export library for being a greeter

This will make it easier for people to write external greeters.

Of course, there are still no guarantees about interface stability.

8 files changed, 1785 insertions, 0 deletions

diff --git a/configure.ac b/configure.ac
index 394d1759..fa05acb9 100644
--- a/configure.ac
+++ b/configure.ac
@@ -194,6 +194,14 @@ AC_PATH_PROG(GCONFTOOL, gconftool-2)
 
 AM_GCONF_SOURCE_2
 
+LIBGDMGREETER_LIBS="$SIMPLE_GREETER_LIBS"
+AC_SUBST(LIBGDMGREETER_LIBS)
+LIBGDMGREETER_CFLAGS="$SIMPLE_GREETER_CFLAGS"
+AC_SUBST(LIBGDMGREETER_CFLAGS)
+GOBJECT_INTROSPECTION_CHECK([0.9.12])
+LIBGDMGREETER_GIR_INCLUDES="GLib-2.0 GObject-2.0 DBusGLib-1.0"
+AC_SUBST(LIBGDMGREETER_GIR_INCLUDES)
+
 dnl ---------------------------------------------------------------------------
 dnl - Configuration file stuff
 dnl ---------------------------------------------------------------------------
@@ -1421,6 +1429,8 @@ Makefile
 daemon/Makefile
 docs/Makefile
 gui/Makefile
+gui/libgdmgreeter/Makefile
+gui/libgdmgreeter/gdmgreeter.pc
 gui/simple-greeter/Makefile
 gui/simple-greeter/libgdmsimplegreeter/Makefile
 gui/simple-greeter/libgdmsimplegreeter/gdmsimplegreeter.pc
diff --git a/gui/Makefile.am b/gui/Makefile.am
index bda3f7a7..d14ed464 100644
--- a/gui/Makefile.am
+++ b/gui/Makefile.am
@@ -1,6 +1,7 @@
 NULL =
 
 SUBDIRS =			\
+	libgdmgreeter		\
 	simple-greeter		\
 	$(NULL)
 
diff --git a/gui/libgdmgreeter/Makefile.am b/gui/libgdmgreeter/Makefile.am
new file mode 100644
index 00000000..f1e2a516
--- /dev/null
+++ b/gui/libgdmgreeter/Makefile.am
@@ -0,0 +1,78 @@
+END_OF_LIST =
+
+BUILT_SOURCES = $(END_OF_LIST)
+CLEANFILES = $(END_OF_LIST)
+
+AM_CPPFLAGS = \
+        -I.                                                                   \
+        -I..                                                                  \
+        -DG_LOG_DOMAIN=\"GdmGreeter\"                                         \
+        -DDMCONFDIR=\""$(dmconfdir)"\"                                        \
+        -DDATADIR=\""$(datadir)"\"                                            \
+        $(END_OF_LIST)
+
+lib_LTLIBRARIES =                                                             \
+        libgdmgreeter.la                                                      \
+        $(END_OF_LIST)
+
+libgdmgreeterdir = $(includedir)/gdm/greeter
+libgdmgreeter_HEADERS =                                                       \
+        gdm-greeter-client.h                                                  \
+        gdm-greeter-sessions.h                                                \
+        $(END_OF_LIST)
+
+libgdmgreeter_la_CFLAGS =                                                     \
+        $(LIBGDMGREETER_CFLAGS)                                               \
+        $(END_OF_LIST)
+libgdmgreeter_la_LDFLAGS =                                                    \
+        -export-symbols-regex '^[^_].*'                                       \
+        -version-info $(LT_CURRENT):$(LT_REVISION):$(LT_AGE)                  \
+        -no-undefined                                                         \
+        $(END_OF_LIST)
+
+libgdmgreeter_la_LIBADD =                                                     \
+        $(LIBGDMGREETER_LIBS)                                                 \
+        $(END_OF_LIST)
+
+libgdmgreeter_la_SOURCES =                                                    \
+        $(libgdmgreeter_HEADERS)                                              \
+        gdm-greeter-client.c                                                  \
+        gdm-greeter-sessions.c                                                \
+        $(END_OF_LIST)
+
+pkgconfigdir = $(libdir)/pkgconfig
+dist_pkgconfig_DATA = gdmgreeter.pc
+
+-include $(INTROSPECTION_MAKEFILE)
+
+if HAVE_INTROSPECTION
+girdir = $(datadir)/gir-1.0
+gir_DATA = GdmGreeter-1.0.gir
+typelibsdir = $(libdir)/girepository-1.0
+typelibs_DATA = $(gir_DATA:.gir=.typelib)
+INTROSPECTION_GIRS = $(gir_DATA)
+
+GdmGreeter-1.0.gir:                                                      \
+        $(INTROSPECTION_SCANNER)                                              \
+        libgdmgreeter.la                                                      \
+        Makefile                                                              \
+        $(END_OF_LIST)
+
+GdmGreeter_1_0_gir_SCANNERFLAGS =                                        \
+        --warn-all                                                            \
+        --namespace=GdmGreeter                                                \
+        --identifier-prefix GdmGreeter                                        \
+        $(libgdmgreeter_la_CFLAGS)                                            \
+        $(END_OF_LIST)
+
+GdmGreeter_1_0_gir_INCLUDES = $(LIBGDMGREETER_GIR_INCLUDES)
+GdmGreeter_1_0_gir_LIBS = libgdmgreeter.la
+GdmGreeter_1_0_gir_FILES =                                                    \
+        $(filter-out %-private.h, $(libgdmgreeter_la_SOURCES))                \
+        $(BUILT_SOURCES)                                                      \
+        $(END_OF_LIST)
+
+CLEANFILES += $(gir_DATA) $(typelibs_DATA)
+endif
+
+MAINTAINERCLEANFILES = Makefile.in
diff --git a/gui/libgdmgreeter/gdm-greeter-client.c b/gui/libgdmgreeter/gdm-greeter-client.c
new file mode 100644
index 00000000..6cf5b588
--- /dev/null
+++ b/gui/libgdmgreeter/gdm-greeter-client.c
@@ -0,0 +1,1243 @@
+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 8 -*-
+ *
+ * Copyright (C) 2007 William Jon McCann <mccann@jhu.edu>
+ *
+ * This program 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 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ */
+
+#include "config.h"
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <string.h>
+
+#include <glib.h>
+#include <glib/gi18n.h>
+#include <glib-object.h>
+#define DBUS_API_SUBJECT_TO_CHANGE
+#include <dbus/dbus.h>
+#include <dbus/dbus-glib.h>
+#include <dbus/dbus-glib-lowlevel.h>
+
+#include "gdm-greeter-client.h"
+
+#define GDM_GREETER_CLIENT_GET_PRIVATE(o) (G_TYPE_INSTANCE_GET_PRIVATE ((o), GDM_TYPE_GREETER_CLIENT, GdmGreeterClientPrivate))
+
+#define GREETER_SERVER_DBUS_PATH      "/org/gnome/DisplayManager/GreeterServer"
+#define GREETER_SERVER_DBUS_INTERFACE "org.gnome.DisplayManager.GreeterServer"
+
+#define GDM_DBUS_NAME              "org.gnome.DisplayManager"
+#define GDM_DBUS_DISPLAY_INTERFACE "org.gnome.DisplayManager.Display"
+
+struct GdmGreeterClientPrivate
+{
+        DBusConnection   *connection;
+        char             *address;
+
+        char             *display_id;
+        gboolean          display_is_local;
+
+        guint32           is_connected : 1;
+};
+
+enum {
+        PROP_0,
+        PROP_DISPLAY_IS_LOCAL
+};
+
+enum {
+        INFO,
+        PROBLEM,
+        INFO_QUERY,
+        SECRET_INFO_QUERY,
+        SERVICE_UNAVAILABLE,
+        READY,
+        CONVERSATION_STOPPED,
+        RESET,
+        AUTHENTICATION_FAILED,
+        SELECTED_USER_CHANGED,
+        DEFAULT_SESSION_CHANGED,
+        TIMED_LOGIN_REQUESTED,
+        SESSION_OPENED,
+        LAST_SIGNAL
+};
+
+static guint gdm_greeter_client_signals [LAST_SIGNAL];
+
+static void     gdm_greeter_client_class_init  (GdmGreeterClientClass *klass);
+static void     gdm_greeter_client_init        (GdmGreeterClient      *greeter_client);
+static void     gdm_greeter_client_finalize    (GObject              *object);
+
+G_DEFINE_TYPE (GdmGreeterClient, gdm_greeter_client, G_TYPE_OBJECT)
+
+static gpointer client_object = NULL;
+
+GQuark
+gdm_greeter_client_error_quark (void)
+{
+        static GQuark error_quark = 0;
+
+        if (error_quark == 0)
+                error_quark = g_quark_from_static_string ("gdm-greeter-client");
+
+        return error_quark;
+}
+
+/**
+ * gdm_greeter_client_get_display_is_local:
+ *
+ * @client: a #GdmGreeterClient
+ *
+ * Returns: %TRUE if display is local display
+ */
+gboolean
+gdm_greeter_client_get_display_is_local (GdmGreeterClient *client)
+{
+        g_return_val_if_fail (GDM_IS_GREETER_CLIENT (client), FALSE);
+
+        return client->priv->display_is_local;
+}
+
+static void
+emit_string_and_int_signal_for_message (GdmGreeterClient *client,
+                                        const char       *name,
+                                        DBusMessage      *message,
+                                        int               signal)
+{
+        DBusError   error;
+        const char *text;
+        int         number;
+        dbus_bool_t res;
+
+        dbus_error_init (&error);
+        res = dbus_message_get_args (message,
+                                     &error,
+                                     DBUS_TYPE_STRING, &text,
+                                     DBUS_TYPE_INT32, &number,
+                                     DBUS_TYPE_INVALID);
+        if (res) {
+
+                g_debug ("GdmGreeterClient: Received %s (%s %d)", name, text, number);
+
+                g_signal_emit (client,
+                               gdm_greeter_client_signals[signal],
+                               0, text, number);
+        } else {
+                g_warning ("Unable to get arguments: %s", error.message);
+                dbus_error_free (&error);
+        }
+}
+
+static void
+emit_string_and_string_signal_for_message (GdmGreeterClient *client,
+                                           const char       *name,
+                                           DBusMessage      *message,
+                                           int               signal)
+{
+        DBusError   error;
+        char *text1;
+        char *text2;
+        dbus_bool_t res;
+
+        dbus_error_init (&error);
+        res = dbus_message_get_args (message,
+                                     &error,
+                                     DBUS_TYPE_STRING, &text1,
+                                     DBUS_TYPE_STRING, &text2,
+                                     DBUS_TYPE_INVALID);
+        if (res) {
+
+                g_debug ("GdmGreeterClient: Received %s (%s, %s)", name, text1, text2);
+
+                g_signal_emit (client,
+                               gdm_greeter_client_signals[signal],
+                               0, text1, text2);
+        } else {
+                g_warning ("Unable to get arguments: %s", error.message);
+                dbus_error_free (&error);
+        }
+        dbus_error_free (&error);
+}
+
+static void
+emit_string_signal_for_message (GdmGreeterClient *client,
+                                const char       *name,
+                                DBusMessage      *message,
+                                int               signal)
+{
+        DBusError   error;
+        const char *text;
+        dbus_bool_t res;
+
+        dbus_error_init (&error);
+        res = dbus_message_get_args (message,
+                                     &error,
+                                     DBUS_TYPE_STRING, &text,
+                                     DBUS_TYPE_INVALID);
+        if (res) {
+
+                g_debug ("GdmGreeterClient: Received %s (%s)", name, text);
+
+                g_signal_emit (client,
+                               gdm_greeter_client_signals[signal],
+                               0, text);
+        } else {
+                g_warning ("Unable to get arguments: %s", error.message);
+                dbus_error_free (&error);
+        }
+}
+
+static void
+on_selected_user_changed (GdmGreeterClient *client,
+                          DBusMessage      *message)
+{
+        emit_string_signal_for_message (client, "SelectedUserChanged", message, SELECTED_USER_CHANGED);
+}
+
+static void
+on_default_session_changed (GdmGreeterClient *client,
+                            DBusMessage      *message)
+{
+        emit_string_signal_for_message (client, "DefaultSessionNameChanged", message, DEFAULT_SESSION_CHANGED);
+}
+
+static void
+on_timed_login_requested (GdmGreeterClient *client,
+                          DBusMessage      *message)
+{
+        emit_string_and_int_signal_for_message (client, "TimedLoginRequested", message, TIMED_LOGIN_REQUESTED);
+}
+
+static void
+on_session_opened (GdmGreeterClient *client,
+                   DBusMessage      *message)
+{
+        emit_string_signal_for_message (client, "SessionOpened", message, SESSION_OPENED);
+}
+
+static void
+on_info_query (GdmGreeterClient *client,
+               DBusMessage      *message)
+{
+        emit_string_and_string_signal_for_message (client, "InfoQuery", message, INFO_QUERY);
+}
+
+static void
+on_secret_info_query (GdmGreeterClient *client,
+                      DBusMessage      *message)
+{
+        emit_string_and_string_signal_for_message (client, "SecretInfoQuery", message, SECRET_INFO_QUERY);
+}
+
+static void
+on_info (GdmGreeterClient *client,
+         DBusMessage      *message)
+{
+        emit_string_and_string_signal_for_message (client, "Info", message, INFO);
+}
+
+static void
+on_problem (GdmGreeterClient *client,
+            DBusMessage      *message)
+{
+        emit_string_and_string_signal_for_message (client, "Problem", message, PROBLEM);
+}
+
+static void
+on_service_unavailable (GdmGreeterClient *client,
+                        DBusMessage      *message)
+{
+        emit_string_signal_for_message (client, "ServiceUnavailable", message, SERVICE_UNAVAILABLE);
+}
+
+static void
+on_ready (GdmGreeterClient *client,
+          DBusMessage      *message)
+{
+        emit_string_signal_for_message (client, "Ready", message, READY);
+}
+
+static void
+on_conversation_stopped (GdmGreeterClient *client,
+                         DBusMessage      *message)
+{
+        emit_string_signal_for_message (client, "ConversationStopped", message, CONVERSATION_STOPPED);
+}
+
+static void
+on_reset (GdmGreeterClient *client,
+          DBusMessage      *message)
+{
+        g_debug ("GdmGreeterClient: Reset");
+
+        g_signal_emit (client,
+                       gdm_greeter_client_signals[RESET],
+                       0);
+}
+
+static void
+on_authentication_failed (GdmGreeterClient *client,
+                          DBusMessage      *message)
+{
+        g_debug ("GdmGreeterClient: Authentication failed");
+
+        g_signal_emit (client,
+                       gdm_greeter_client_signals[AUTHENTICATION_FAILED],
+                       0);
+}
+
+static gboolean
+send_dbus_string_method (DBusConnection *connection,
+                         const char     *method,
+                         const char     *payload)
+{
+        DBusError       error;
+        DBusMessage    *message;
+        DBusMessage    *reply;
+        DBusMessageIter iter;
+        const char     *str;
+
+        if (payload != NULL) {
+                str = payload;
+        } else {
+                str = "";
+        }
+
+        g_debug ("GdmGreeterClient: Calling %s", method);
+        message = dbus_message_new_method_call (NULL,
+                                                GREETER_SERVER_DBUS_PATH,
+                                                GREETER_SERVER_DBUS_INTERFACE,
+                                                method);
+        if (message == NULL) {
+                g_warning ("Couldn't allocate the D-Bus message");
+                return FALSE;
+        }
+
+        dbus_message_iter_init_append (message, &iter);
+        dbus_message_iter_append_basic (&iter,
+                                        DBUS_TYPE_STRING,
+                                        &str);
+
+        dbus_error_init (&error);
+        reply = dbus_connection_send_with_reply_and_block (connection,
+                                                           message,
+                                                           -1,
+                                                           &error);
+
+        dbus_message_unref (message);
+
+        if (dbus_error_is_set (&error)) {
+                g_warning ("%s %s raised: %s\n",
+                           method,
+                           error.name,
+                           error.message);
+                return FALSE;
+        }
+        if (reply != NULL) {
+                dbus_message_unref (reply);
+        }
+        dbus_connection_flush (connection);
+
+        return TRUE;
+}
+
+static gboolean
+send_dbus_string_and_bool_method (DBusConnection *connection,
+                                  const char     *method,
+                                  const char     *string_payload,
+                                  gboolean        bool_payload)
+{
+        DBusMessage    *message;
+        DBusMessageIter iter;
+        const char     *str;
+
+        if (string_payload != NULL) {
+                str = string_payload;
+        } else {
+                str = "";
+        }
+
+        g_debug ("GdmGreeterClient: Calling %s", method);
+        message = dbus_message_new_method_call (NULL,
+                                                GREETER_SERVER_DBUS_PATH,
+                                                GREETER_SERVER_DBUS_INTERFACE,
+                                                method);
+        if (message == NULL) {
+                g_warning ("Couldn't allocate the D-Bus message");
+                return FALSE;
+        }
+
+        dbus_message_iter_init_append (message, &iter);
+        dbus_message_iter_append_basic (&iter,
+                                        DBUS_TYPE_STRING,
+                                        &str);
+
+        dbus_message_iter_append_basic (&iter,
+                                        DBUS_TYPE_BOOLEAN,
+                                        &bool_payload);
+        dbus_message_set_no_reply (message, TRUE);
+
+        dbus_connection_send (connection, message, NULL);
+
+        dbus_message_unref (message);
+
+        dbus_connection_flush (connection);
+
+        return TRUE;
+}
+
+static gboolean
+send_dbus_string_and_string_method (DBusConnection *connection,
+                                    const char     *method,
+                                    const char     *payload1,
+                                    const char     *payload2)
+{
+        DBusError       error;
+        DBusMessage    *message;
+        DBusMessage    *reply;
+        DBusMessageIter iter;
+        const char     *str;
+
+        g_debug ("GdmGreeterClient: Calling %s", method);
+        message = dbus_message_new_method_call (NULL,
+                                                GREETER_SERVER_DBUS_PATH,
+                                                GREETER_SERVER_DBUS_INTERFACE,
+                                                method);
+        if (message == NULL) {
+                g_warning ("Couldn't allocate the D-Bus message");
+                return FALSE;
+        }
+
+        dbus_message_iter_init_append (message, &iter);
+
+        if (payload1 != NULL) {
+                str = payload1;
+        } else {
+                str = "";
+        }
+        dbus_message_iter_append_basic (&iter,
+                                        DBUS_TYPE_STRING,
+                                        &str);
+
+        if (payload2 != NULL) {
+                str = payload2;
+        } else {
+                str = "";
+        }
+        dbus_message_iter_append_basic (&iter,
+                                        DBUS_TYPE_STRING,
+                                        &str);
+
+        dbus_error_init (&error);
+        reply = dbus_connection_send_with_reply_and_block (connection,
+                                                           message,
+                                                           -1,
+                                                           &error);
+
+        dbus_message_unref (message);
+
+        if (dbus_error_is_set (&error)) {
+                g_warning ("%s %s raised: %s\n",
+                           method,
+                           error.name,
+                           error.message);
+                return FALSE;
+        }
+        if (reply != NULL) {
+                dbus_message_unref (reply);
+        }
+        dbus_connection_flush (connection);
+
+        return TRUE;
+}
+
+static gboolean
+send_dbus_void_method (DBusConnection *connection,
+                       const char     *method)
+{
+        DBusError       error;
+        DBusMessage    *message;
+        DBusMessage    *reply;
+
+        g_debug ("GdmGreeterClient: Calling %s", method);
+        message = dbus_message_new_method_call (NULL,
+                                                GREETER_SERVER_DBUS_PATH,
+                                                GREETER_SERVER_DBUS_INTERFACE,
+                                                method);
+        if (message == NULL) {
+                g_warning ("Couldn't allocate the D-Bus message");
+                return FALSE;
+        }
+
+        dbus_error_init (&error);
+        reply = dbus_connection_send_with_reply_and_block (connection,
+                                                           message,
+                                                           -1,
+                                                           &error);
+
+        dbus_message_unref (message);
+
+        if (dbus_error_is_set (&error)) {
+                g_warning ("%s %s raised: %s\n",
+                           method,
+                           error.name,
+                           error.message);
+                return FALSE;
+        }
+        if (reply != NULL) {
+                dbus_message_unref (reply);
+        }
+        dbus_connection_flush (connection);
+
+        return TRUE;
+}
+
+/**
+ * gdm_greeter_call_start_conversation:
+ *
+ * @client: a #GdmGreeterClient
+ * @service_name: PAM service name
+ *
+ * Tells GDM to prepare to start a PAM conversation with
+ * the specified PAM service.
+ *
+ * Normally, this would get called when the greeter first
+ * starts up, either one call to the "gdm" service or one
+ * for each auth method (say "gdm-password", "gdm-fingerprint",
+ * "gdm-smartcard")
+ *
+ * After the conversation has been started, the ready signal
+ * will be emitted.
+ */
+void
+gdm_greeter_client_call_start_conversation (GdmGreeterClient *client,
+                                            const char       *service_name)
+{
+        send_dbus_string_method (client->priv->connection,
+                                 "StartConversation", service_name);
+}
+
+/**
+ * gdm_greeter_call_begin_auto_login:
+ *
+ * @client: a #GdmGreeterClient
+ * @username: user to auto login or %NULL to use the configured default
+ *
+ * Tells GDM to log the user in without first authenticating.
+ *
+ * Normally, this would get called after a timed-login-requested
+ * signal once the time out has been reached.
+ */
+void
+gdm_greeter_client_call_begin_auto_login (GdmGreeterClient *client,
+                                          const char       *username)
+{
+        if (username == NULL) {
+                username = "__auto";
+        }
+
+        send_dbus_string_method (client->priv->connection,
+                                 "BeginAutoLogin", username);
+}
+
+/**
+ * gdm_greeter_call_begin_verification:
+ *
+ * @client: a #GdmGreeterClient
+ * @service_name: PAM service name
+ *
+ * Tells GDM to start the PAM authentication process with no specified
+ * user name.
+ *
+ * This should only be called after the ready signal is emitted for
+ * @service_name.
+ *
+ * Normally, this would get called if the greeter has no user list, or
+ * if the user clicks "Other" or "Not Listed?" in the user list.
+ */
+void
+gdm_greeter_client_call_begin_verification (GdmGreeterClient *client,
+                                            const char       *service_name)
+{
+        send_dbus_string_method (client->priv->connection,
+                                 "BeginVerification", service_name);
+}
+
+/**
+ * gdm_greeter_call_begin_verification_for_user:
+ *
+ * @client: a #GdmGreeterClient
+ * @service_name: PAM service name
+ * @username: user to start verification process for
+ *
+ * Tells GDM to start the PAM authentication process with the @username
+ * user name.
+ *
+ * This should only be called after the ready signal is emitted for
+ * @service_name.
+ *
+ * Normally, this would get called in reponse to a user getting selected
+ * from the user list.  If the greeter doesn't have a user list, it's
+ * better to call gdm_greeter_client_call_begin_verification() and let
+ * the PAM service handle asking for a username, than using this function.
+ */
+void
+gdm_greeter_client_call_begin_verification_for_user (GdmGreeterClient *client,
+                                                     const char       *service_name,
+                                                     const char       *username)
+{
+        send_dbus_string_and_string_method (client->priv->connection,
+                                            "BeginVerificationForUser",
+                                            service_name,
+                                            username);
+}
+
+/**
+ * gdm_greeter_call_answer_query:
+ *
+ * @client: a #GdmGreeterClient
+ * @service_name: PAM service name
+ * @answer: The answer to the currently pending PAM question.
+ *
+ * Responds to GDM's pending request for information.
+ *
+ * This should only be called after the info-query or secret-info-query signal is
+ * emitted for * @service_name.
+ *
+ * Normally, this would get called after the user types in an answer.
+ */
+void
+gdm_greeter_client_call_answer_query (GdmGreeterClient *client,
+                                      const char       *service_name,
+                                      const char       *answer)
+{
+        send_dbus_string_and_string_method (client->priv->connection,
+                                            "AnswerQuery",
+                                            service_name,
+                                            answer);
+}
+
+/**
+ * gdm_greeter_call_start_session_when_ready:
+ *
+ * @client: a #GdmGreeterClient
+ * @service_name: PAM service name
+ * @should_start_session: whether to block the login process
+ *
+ * After the user has successfully interacted with PAM, GDM waits
+ * for a final go ahead before finishing the login process and starting the
+ * users session.
+ *
+ * This call gives that go ahead.
+ *
+ * Normally, you would call this after the user has had a chance to interact
+ * with any important, non-login related information on the login screen
+ * (like a session selector).
+ */
+void
+gdm_greeter_client_call_start_session_when_ready  (GdmGreeterClient *client,
+                                                   const char       *service_name,
+                                                   gboolean          should_start_session)
+{
+        send_dbus_string_and_bool_method (client->priv->connection,
+                                          "StartSessionWhenReady",
+                                          service_name,
+                                          should_start_session);
+}
+
+/**
+ * gdm_greeter_call_select_session:
+ *
+ * @client: a #GdmGreeterClient
+ * @session: session from /usr/share/xsessions to start
+ *
+ * Select a session for the user to login with.
+ *
+ * Normally, you would call this if the user selects a specific session in
+ * a list on screen somewhere.
+ */
+void
+gdm_greeter_client_call_select_session (GdmGreeterClient *client,
+                                        const char       *session)
+{
+        send_dbus_string_method (client->priv->connection,
+                                 "SelectSession",
+                                 session);
+}
+
+/**
+ * gdm_greeter_call_select_user:
+ *
+ * @client: a #GdmGreeterClient
+ * @user:  a user name
+ *
+ * Select a user to login with.
+ *
+ * Normally, you would call this if the user selects a specific session in
+ * a list on screen somewhere.
+ */
+void
+gdm_greeter_client_call_select_user (GdmGreeterClient *client,
+                                     const char       *user)
+{
+        send_dbus_string_method (client->priv->connection,
+                                 "SelectUser",
+                                 user);
+}
+
+/**
+ * gdm_greeter_call_select_hostname:
+ *
+ * @client: a #GdmGreeterClient
+ * @hostname:  a hostname
+ *
+ * Select a user to login with.
+ *
+ * Normally, you would call this from a chooser to select a specific host.
+ */
+void
+gdm_greeter_client_call_select_hostname (GdmGreeterClient *client,
+                                         const char       *hostname)
+{
+        send_dbus_string_method (client->priv->connection,
+                                 "SelectHostname",
+                                 hostname);
+}
+
+/**
+ * gdm_greeter_call_canel:
+ *
+ * @client: a #GdmGreeterClient
+ *
+ * Cancel all pending PAM conversations.
+ *
+ * Normally you would call this if the user hits a Cancel button when
+ * asked a question they don't want to answer.
+ */
+void
+gdm_greeter_client_call_cancel (GdmGreeterClient *client)
+{
+        send_dbus_void_method (client->priv->connection,
+                               "Cancel");
+}
+
+/**
+ * gdm_greeter_call_disconnect:
+ *
+ * @client: a #GdmGreeterClient
+ *
+ * Disconnect from gdm slave.
+ *
+ * You shouldn't call this unless the connection
+ * is remote.
+ */
+void
+gdm_greeter_client_call_disconnect (GdmGreeterClient *client)
+{
+        g_return_if_fail (gdm_greeter_client_get_display_is_local (client) == FALSE);
+
+        send_dbus_void_method (client->priv->connection,
+                               "Disconnect");
+}
+
+static gboolean
+send_get_display_id (GdmGreeterClient *client,
+                     const char       *method,
+                     char            **answerp)
+{
+        DBusError       error;
+        DBusMessage    *message;
+        DBusMessage    *reply;
+        DBusMessageIter iter;
+        gboolean        ret;
+        const char     *answer;
+
+        ret = FALSE;
+
+        g_debug ("GdmGreeterClient: Calling %s", method);
+        message = dbus_message_new_method_call (NULL,
+                                                GREETER_SERVER_DBUS_PATH,
+                                                GREETER_SERVER_DBUS_INTERFACE,
+                                                method);
+        if (message == NULL) {
+                g_warning ("Couldn't allocate the D-Bus message");
+                return FALSE;
+        }
+
+        dbus_error_init (&error);
+        reply = dbus_connection_send_with_reply_and_block (client->priv->connection,
+                                                           message,
+                                                           -1,
+                                                           &error);
+        dbus_message_unref (message);
+
+        if (dbus_error_is_set (&error)) {
+                g_warning ("%s %s raised: %s\n",
+                           method,
+                           error.name,
+                           error.message);
+                goto out;
+        }
+
+        dbus_message_iter_init (reply, &iter);
+        dbus_message_iter_get_basic (&iter, &answer);
+        if (answerp != NULL) {
+                *answerp = g_strdup (answer);
+        }
+        ret = TRUE;
+
+        dbus_message_unref (reply);
+        dbus_connection_flush (client->priv->connection);
+
+ out:
+
+        return ret;
+}
+
+
+static char *
+gdm_greeter_client_call_get_display_id (GdmGreeterClient *client)
+{
+        char *display_id;
+
+        display_id = NULL;
+        send_get_display_id (client,
+                             "GetDisplayId",
+                             &display_id);
+
+        return display_id;
+}
+
+static void
+cache_display_values (GdmGreeterClient *client)
+{
+        DBusGProxy      *display_proxy;
+        DBusGConnection *connection;
+        GError          *error;
+        gboolean         res;
+
+        g_free (client->priv->display_id);
+        client->priv->display_id = gdm_greeter_client_call_get_display_id (client);
+        if (client->priv->display_id == NULL) {
+                return;
+        }
+
+        error = NULL;
+        connection = dbus_g_bus_get (DBUS_BUS_SYSTEM, &error);
+        if (connection == NULL) {
+                if (error != NULL) {
+                        g_critical ("error getting system bus: %s", error->message);
+                        g_error_free (error);
+                }
+                return;
+        }
+
+        g_debug ("GdmGreeterClient: Creating proxy for %s", client->priv->display_id);
+        display_proxy = dbus_g_proxy_new_for_name (connection,
+                                                   GDM_DBUS_NAME,
+                                                   client->priv->display_id,
+                                                   GDM_DBUS_DISPLAY_INTERFACE);
+        /* cache some values up front */
+        error = NULL;
+        res = dbus_g_proxy_call (display_proxy,
+                                 "IsLocal",
+                                 &error,
+                                 G_TYPE_INVALID,
+                                 G_TYPE_BOOLEAN, &client->priv->display_is_local,
+                                 G_TYPE_INVALID);
+        if (! res) {
+                if (error != NULL) {
+                        g_warning ("Failed to get value: %s", error->message);
+                        g_error_free (error);
+                } else {
+                        g_warning ("Failed to get value");
+                }
+        }
+}
+
+static DBusHandlerResult
+client_dbus_handle_message (DBusConnection *connection,
+                            DBusMessage    *message,
+                            void           *user_data,
+                            dbus_bool_t     local_interface)
+{
+        GdmGreeterClient *client = GDM_GREETER_CLIENT (user_data);
+
+        g_return_val_if_fail (connection != NULL, DBUS_HANDLER_RESULT_NOT_YET_HANDLED);
+        g_return_val_if_fail (message != NULL, DBUS_HANDLER_RESULT_NOT_YET_HANDLED);
+
+        if (dbus_message_is_signal (message, GREETER_SERVER_DBUS_INTERFACE, "InfoQuery")) {
+                on_info_query (client, message);
+        } else if (dbus_message_is_signal (message, GREETER_SERVER_DBUS_INTERFACE, "SecretInfoQuery")) {
+                on_secret_info_query (client, message);
+        } else if (dbus_message_is_signal (message, GREETER_SERVER_DBUS_INTERFACE, "Info")) {
+                on_info (client, message);
+        } else if (dbus_message_is_signal (message, GREETER_SERVER_DBUS_INTERFACE, "Problem")) {
+                on_problem (client, message);
+        } else if (dbus_message_is_signal (message, GREETER_SERVER_DBUS_INTERFACE, "ServiceUnavailable")) {
+                on_service_unavailable (client, message);
+        } else if (dbus_message_is_signal (message, GREETER_SERVER_DBUS_INTERFACE, "Ready")) {
+                on_ready (client, message);
+        } else if (dbus_message_is_signal (message, GREETER_SERVER_DBUS_INTERFACE, "ConversationStopped")) {
+                on_conversation_stopped (client, message);
+        } else if (dbus_message_is_signal (message, GREETER_SERVER_DBUS_INTERFACE, "Reset")) {
+                on_reset (client, message);
+        } else if (dbus_message_is_signal (message, GREETER_SERVER_DBUS_INTERFACE, "AuthenticationFailed")) {
+                on_authentication_failed (client, message);
+        } else if (dbus_message_is_signal (message, GREETER_SERVER_DBUS_INTERFACE, "SelectedUserChanged")) {
+                on_selected_user_changed (client, message);
+        } else if (dbus_message_is_signal (message, GREETER_SERVER_DBUS_INTERFACE, "DefaultSessionNameChanged")) {
+                on_default_session_changed (client, message);
+        } else if (dbus_message_is_signal (message, GREETER_SERVER_DBUS_INTERFACE, "TimedLoginRequested")) {
+                on_timed_login_requested (client, message);
+        } else if (dbus_message_is_signal (message, GREETER_SERVER_DBUS_INTERFACE, "SessionOpened")) {
+                on_session_opened (client, message);
+        } else {
+                return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
+        }
+
+        return DBUS_HANDLER_RESULT_HANDLED;
+}
+
+static DBusHandlerResult
+client_dbus_filter_function (DBusConnection *connection,
+                             DBusMessage    *message,
+                             void           *user_data)
+{
+        GdmGreeterClient *client = GDM_GREETER_CLIENT (user_data);
+        const char       *path;
+
+        path = dbus_message_get_path (message);
+
+        g_debug ("GdmGreeterClient: obj_path=%s interface=%s method=%s",
+                 dbus_message_get_path (message),
+                 dbus_message_get_interface (message),
+                 dbus_message_get_member (message));
+
+        if (dbus_message_is_signal (message, DBUS_INTERFACE_LOCAL, "Disconnected")
+            && strcmp (path, DBUS_PATH_LOCAL) == 0) {
+
+                g_message ("Got disconnected from the session message bus");
+
+                dbus_connection_unref (connection);
+                client->priv->connection = NULL;
+
+        } else if (dbus_message_is_signal (message,
+                                           DBUS_INTERFACE_DBUS,
+                                           "NameOwnerChanged")) {
+                g_debug ("GdmGreeterClient: Name owner changed?");
+        } else {
+                return client_dbus_handle_message (connection, message, user_data, FALSE);
+        }
+
+        return DBUS_HANDLER_RESULT_HANDLED;
+}
+
+/**
+ * gdm_greeter_client_open_connection:
+ *
+ * @client: a #GdmGreeterClient
+ *
+ * Initiates a connection to GDM daemon "slave" process.
+ *
+ * This function should be called before doing other calls.
+ *
+ * Returns: %TRUE if connected, or %FALSE if unavailable
+ */
+gboolean
+gdm_greeter_client_open_connection (GdmGreeterClient  *client,
+                                    GError           **error)
+{
+        DBusError local_error;
+
+        g_return_val_if_fail (GDM_IS_GREETER_CLIENT (client), FALSE);
+        g_return_val_if_fail (!client->priv->is_connected, TRUE);
+
+        if (client->priv->address == NULL) {
+                g_warning ("GDM_GREETER_DBUS_ADDRESS not set");
+                g_set_error (error,
+                             GDM_GREETER_CLIENT_ERROR,
+                             GDM_GREETER_CLIENT_ERROR_GENERIC,
+                             "GDM_GREETER_DBUS_ADDRESS not set");
+                goto out;
+        }
+
+        g_debug ("GdmGreeterClient: connecting to address: %s", client->priv->address);
+
+        dbus_error_init (&local_error);
+        client->priv->connection = dbus_connection_open (client->priv->address, &local_error);
+        if (client->priv->connection == NULL) {
+                if (dbus_error_is_set (&local_error)) {
+                        g_warning ("error opening connection: %s", local_error.message);
+                        g_set_error (error,
+                                     GDM_GREETER_CLIENT_ERROR,
+                                     GDM_GREETER_CLIENT_ERROR_GENERIC,
+                                     "%s", local_error.message);
+                        dbus_error_free (&local_error);
+                } else {
+                        g_warning ("Unable to open connection");
+                }
+                goto out;
+        }
+
+        dbus_connection_setup_with_g_main (client->priv->connection, NULL);
+        dbus_connection_set_exit_on_disconnect (client->priv->connection, TRUE);
+
+        dbus_connection_add_filter (client->priv->connection,
+                                    client_dbus_filter_function,
+                                    client,
+                                    NULL);
+
+        cache_display_values (client);
+
+
+        client->priv->is_connected = TRUE;
+
+ out:
+        return client->priv->is_connected;
+}
+
+static void
+gdm_greeter_client_set_property (GObject      *object,
+                                 guint         prop_id,
+                                 const GValue *value,
+                                 GParamSpec   *pspec)
+{
+        G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+}
+
+static void
+gdm_greeter_client_get_property (GObject    *object,
+                                 guint       prop_id,
+                                 GValue     *value,
+                                 GParamSpec *pspec)
+{
+        GdmGreeterClient *self;
+
+        self = GDM_GREETER_CLIENT (object);
+
+        switch (prop_id) {
+        case PROP_DISPLAY_IS_LOCAL:
+                g_value_set_boolean (value, self->priv->display_is_local);
+                break;
+        default:
+                G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+                break;
+        }
+}
+
+static void
+gdm_greeter_client_class_init (GdmGreeterClientClass *klass)
+{
+        GObjectClass   *object_class = G_OBJECT_CLASS (klass);
+
+        object_class->get_property = gdm_greeter_client_get_property;
+        object_class->set_property = gdm_greeter_client_set_property;
+        object_class->finalize = gdm_greeter_client_finalize;
+
+        g_type_class_add_private (klass, sizeof (GdmGreeterClientPrivate));
+
+        gdm_greeter_client_signals[INFO_QUERY] =
+                g_signal_new ("info-query",
+                              G_OBJECT_CLASS_TYPE (object_class),
+                              G_SIGNAL_RUN_LAST,
+                              G_STRUCT_OFFSET (GdmGreeterClientClass, info_query),
+                              NULL,
+                              NULL,
+                              g_cclosure_marshal_generic,
+                              G_TYPE_NONE,
+                              2,
+                              G_TYPE_STRING, G_TYPE_STRING);
+
+        gdm_greeter_client_signals[SECRET_INFO_QUERY] =
+                g_signal_new ("secret-info-query",
+                              G_OBJECT_CLASS_TYPE (object_class),
+                              G_SIGNAL_RUN_LAST,
+                              G_STRUCT_OFFSET (GdmGreeterClientClass, secret_info_query),
+                              NULL,
+                              NULL,
+                              g_cclosure_marshal_generic,
+                              G_TYPE_NONE,
+                              2,
+                              G_TYPE_STRING, G_TYPE_STRING);
+
+        gdm_greeter_client_signals[INFO] =
+                g_signal_new ("info",
+                              G_OBJECT_CLASS_TYPE (object_class),
+                              G_SIGNAL_RUN_FIRST,
+                              G_STRUCT_OFFSET (GdmGreeterClientClass, info),
+                              NULL,
+                              NULL,
+                              g_cclosure_marshal_generic,
+                              G_TYPE_NONE,
+                              2,
+                              G_TYPE_STRING, G_TYPE_STRING);
+
+        gdm_greeter_client_signals[PROBLEM] =
+                g_signal_new ("problem",
+                              G_OBJECT_CLASS_TYPE (object_class),
+                              G_SIGNAL_RUN_FIRST,
+                              G_STRUCT_OFFSET (GdmGreeterClientClass, problem),
+                              NULL,
+                              NULL,
+                              g_cclosure_marshal_generic,
+                              G_TYPE_NONE,
+                              2,
+                              G_TYPE_STRING, G_TYPE_STRING);
+
+        gdm_greeter_client_signals[SERVICE_UNAVAILABLE] =
+                g_signal_new ("service-unavailable",
+                              G_OBJECT_CLASS_TYPE (object_class),
+                              G_SIGNAL_RUN_FIRST,
+                              G_STRUCT_OFFSET (GdmGreeterClientClass, service_unavailable),
+                              NULL,
+                              NULL,
+                              g_cclosure_marshal_generic,
+                              G_TYPE_NONE, 1, G_TYPE_STRING);
+
+        gdm_greeter_client_signals[READY] =
+                g_signal_new ("ready",
+                              G_OBJECT_CLASS_TYPE (object_class),
+                              G_SIGNAL_RUN_FIRST,
+                              G_STRUCT_OFFSET (GdmGreeterClientClass, ready),
+                              NULL,
+                              NULL,
+                              g_cclosure_marshal_generic,
+                              G_TYPE_NONE,
+                              1, G_TYPE_STRING);
+
+        gdm_greeter_client_signals[CONVERSATION_STOPPED] =
+                g_signal_new ("conversation-stopped",
+                              G_OBJECT_CLASS_TYPE (object_class),
+                              G_SIGNAL_RUN_FIRST,
+                              G_STRUCT_OFFSET (GdmGreeterClientClass, conversation_stopped),
+                              NULL,
+                              NULL,
+                              g_cclosure_marshal_generic,
+                              G_TYPE_NONE,
+                              1, G_TYPE_STRING);
+
+        gdm_greeter_client_signals[RESET] =
+                g_signal_new ("reset",
+                              G_OBJECT_CLASS_TYPE (object_class),
+                              G_SIGNAL_RUN_FIRST,
+                              G_STRUCT_OFFSET (GdmGreeterClientClass, reset),
+                              NULL,
+                              NULL,
+                              g_cclosure_marshal_generic,
+                              G_TYPE_NONE,
+                              0);
+        gdm_greeter_client_signals[AUTHENTICATION_FAILED] =
+                g_signal_new ("authentication-failed",
+                              G_OBJECT_CLASS_TYPE (object_class),
+                              G_SIGNAL_RUN_FIRST,
+                              G_STRUCT_OFFSET (GdmGreeterClientClass, authentication_failed),
+                              NULL,
+                              NULL,
+                              g_cclosure_marshal_generic,
+                              G_TYPE_NONE,
+                              0);
+        gdm_greeter_client_signals[SELECTED_USER_CHANGED] =
+                g_signal_new ("selected-user-changed",
+                              G_OBJECT_CLASS_TYPE (object_class),
+                              G_SIGNAL_RUN_FIRST,
+                              G_STRUCT_OFFSET (GdmGreeterClientClass, selected_user_changed),
+                              NULL,
+                              NULL,
+                              g_cclosure_marshal_generic,
+                              G_TYPE_NONE,
+                              1, G_TYPE_STRING);
+        gdm_greeter_client_signals[DEFAULT_SESSION_CHANGED] =
+                g_signal_new ("default-session-changed",
+                              G_OBJECT_CLASS_TYPE (object_class),
+                              G_SIGNAL_RUN_FIRST,
+                              G_STRUCT_OFFSET (GdmGreeterClientClass, default_session_changed),
+                              NULL,
+                              NULL,
+                              g_cclosure_marshal_generic,
+                              G_TYPE_NONE,
+                              1, G_TYPE_STRING);
+        gdm_greeter_client_signals[TIMED_LOGIN_REQUESTED] =
+                g_signal_new ("timed-login-requested",
+                              G_OBJECT_CLASS_TYPE (object_class),
+                              G_SIGNAL_RUN_FIRST,
+                              G_STRUCT_OFFSET (GdmGreeterClientClass, timed_login_requested),
+                              NULL,
+                              NULL,
+                              g_cclosure_marshal_generic,
+                              G_TYPE_NONE,
+                              2, G_TYPE_STRING, G_TYPE_INT);
+
+        gdm_greeter_client_signals[SESSION_OPENED] =
+                g_signal_new ("session-opened",
+                              G_OBJECT_CLASS_TYPE (object_class),
+                              G_SIGNAL_RUN_FIRST,
+                              G_STRUCT_OFFSET (GdmGreeterClientClass, session_opened),
+                              NULL,
+                              NULL,
+                              g_cclosure_marshal_generic,
+                              G_TYPE_NONE,
+                              1, G_TYPE_STRING);
+
+        g_object_class_install_property (object_class,
+                                         PROP_DISPLAY_IS_LOCAL,
+                                         g_param_spec_boolean ("display-is-local",
+                                                               "display is local",
+                                                               "display is local",
+                                                               FALSE,
+                                                               G_PARAM_READABLE));
+}
+
+static void
+gdm_greeter_client_init (GdmGreeterClient *client)
+{
+
+        client->priv = GDM_GREETER_CLIENT_GET_PRIVATE (client);
+
+        client->priv->address = g_strdup (g_getenv ("GDM_GREETER_DBUS_ADDRESS"));
+}
+
+static void
+gdm_greeter_client_finalize (GObject *object)
+{
+        GdmGreeterClient *client;
+
+        g_return_if_fail (object != NULL);
+        g_return_if_fail (GDM_IS_GREETER_CLIENT (object));
+
+        client = GDM_GREETER_CLIENT (object);
+
+        g_return_if_fail (client->priv != NULL);
+
+        g_free (client->priv->address);
+
+        G_OBJECT_CLASS (gdm_greeter_client_parent_class)->finalize (object);
+}
+
+GdmGreeterClient *
+gdm_greeter_client_new (void)
+{
+        if (client_object != NULL) {
+                g_object_ref (client_object);
+        } else {
+                client_object = g_object_new (GDM_TYPE_GREETER_CLIENT, NULL);
+                g_object_add_weak_pointer (client_object,
+                                           (gpointer *) &client_object);
+        }
+
+        return GDM_GREETER_CLIENT (client_object);
+}
diff --git a/gui/libgdmgreeter/gdm-greeter-client.h b/gui/libgdmgreeter/gdm-greeter-client.h
new file mode 100644
index 00000000..7fa3aaa7
--- /dev/null
+++ b/gui/libgdmgreeter/gdm-greeter-client.h
@@ -0,0 +1,126 @@
+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 8 -*-
+ *
+ * Copyright (C) 2007 William Jon McCann <mccann@jhu.edu>
+ *
+ * This program 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 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ */
+
+#ifndef __GDM_GREETER_CLIENT_H
+#define __GDM_GREETER_CLIENT_H
+
+#include <glib-object.h>
+
+G_BEGIN_DECLS
+
+#define GDM_TYPE_GREETER_CLIENT         (gdm_greeter_client_get_type ())
+#define GDM_GREETER_CLIENT(o)           (G_TYPE_CHECK_INSTANCE_CAST ((o), GDM_TYPE_GREETER_CLIENT, GdmGreeterClient))
+#define GDM_GREETER_CLIENT_CLASS(k)     (G_TYPE_CHECK_CLASS_CAST((k), GDM_TYPE_GREETER_CLIENT, GdmGreeterClientClass))
+#define GDM_IS_GREETER_CLIENT(o)        (G_TYPE_CHECK_INSTANCE_TYPE ((o), GDM_TYPE_GREETER_CLIENT))
+#define GDM_IS_GREETER_CLIENT_CLASS(k)  (G_TYPE_CHECK_CLASS_TYPE ((k), GDM_TYPE_GREETER_CLIENT))
+#define GDM_GREETER_CLIENT_GET_CLASS(o) (G_TYPE_INSTANCE_GET_CLASS ((o), GDM_TYPE_GREETER_CLIENT, GdmGreeterClientClass))
+
+typedef struct GdmGreeterClientPrivate GdmGreeterClientPrivate;
+
+typedef struct
+{
+        GObject                  parent;
+        GdmGreeterClientPrivate *priv;
+} GdmGreeterClient;
+
+typedef struct
+{
+        GObjectClass   parent_class;
+
+        void (* info_query)              (GdmGreeterClient  *client,
+                                          const char        *service_name,
+                                          const char        *query_text);
+
+        void (* secret_info_query)       (GdmGreeterClient  *client,
+                                          const char        *service_name,
+                                          const char        *query_text);
+
+        void (* info)                    (GdmGreeterClient  *client,
+                                          const char        *service_name,
+                                          const char        *info);
+
+        void (* problem)                 (GdmGreeterClient  *client,
+                                          const char        *service_name,
+                                          const char        *problem);
+        void (* service_unavailable)     (GdmGreeterClient  *client,
+                                          const char        *service_name);
+        void (* ready)                   (GdmGreeterClient  *client,
+                                          const char        *service_name);
+        void (* conversation_stopped)    (GdmGreeterClient  *client,
+                                          const char        *service_name);
+        void (* reset)                   (GdmGreeterClient  *client);
+        void (* authentication_failed)   (GdmGreeterClient  *client);
+        void (* selected_user_changed)   (GdmGreeterClient  *client,
+                                          const char        *username);
+        void (* default_session_changed) (GdmGreeterClient  *client,
+                                          const char        *session_id);
+        void (* timed_login_requested)   (GdmGreeterClient  *client,
+                                          const char        *username,
+                                          int                delay);
+        void (* session_opened)          (GdmGreeterClient  *client,
+                                          const char        *service_name);
+} GdmGreeterClientClass;
+
+#define GDM_GREETER_CLIENT_ERROR (gdm_greeter_client_error_quark ())
+
+typedef enum _GdmGreeterClientError {
+        GDM_GREETER_CLIENT_ERROR_GENERIC = 0,
+} GdmGreeterClientError;
+
+GType              gdm_greeter_client_get_type                       (void);
+GQuark             gdm_greeter_client_error_quark                    (void);
+
+GdmGreeterClient * gdm_greeter_client_new                            (void);
+
+gboolean           gdm_greeter_client_open_connection                (GdmGreeterClient *client,
+                                                                      GError          **error);
+gboolean           gdm_greeter_client_get_display_is_local           (GdmGreeterClient *client);
+
+void               gdm_greeter_client_call_start_conversation        (GdmGreeterClient *client,
+                                                                      const char       *service_name);
+void               gdm_greeter_client_call_begin_auto_login          (GdmGreeterClient *client,
+                                                                      const char       *username);
+void               gdm_greeter_client_call_begin_verification        (GdmGreeterClient *client,
+                                                                      const char       *service_name);
+void               gdm_greeter_client_call_begin_verification_for_user (GdmGreeterClient *client,
+                                                                        const char       *service_name,
+                                                                        const char       *username);
+void               gdm_greeter_client_call_cancel                    (GdmGreeterClient *client);
+void               gdm_greeter_client_call_disconnect                (GdmGreeterClient *client);
+void               gdm_greeter_client_call_select_hostname           (GdmGreeterClient *client,
+                                                                      const char       *text);
+void               gdm_greeter_client_call_select_user               (GdmGreeterClient *client,
+                                                                      const char       *text);
+void               gdm_greeter_client_call_select_language           (GdmGreeterClient *client,
+                                                                      const char       *text);
+void               gdm_greeter_client_call_select_session            (GdmGreeterClient *client,
+                                                                      const char       *text);
+void               gdm_greeter_client_call_answer_query              (GdmGreeterClient *client,
+                                                                      const char       *service_name,
+                                                                      const char       *text);
+
+void               gdm_greeter_client_call_start_session_when_ready  (GdmGreeterClient *client,
+                                                                      const char       *service_name,
+                                                                      gboolean          should_start_session);
+
+
+G_END_DECLS
+
+#endif /* __GDM_GREETER_CLIENT_H */
diff --git a/gui/libgdmgreeter/gdm-greeter-sessions.c b/gui/libgdmgreeter/gdm-greeter-sessions.c
new file mode 100644
index 00000000..fe342930
--- /dev/null
+++ b/gui/libgdmgreeter/gdm-greeter-sessions.c
@@ -0,0 +1,280 @@
+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 8 -*-
+ *
+ * Copyright 2008 Red Hat, Inc,
+ *           2007 William Jon McCann <mccann@jhu.edu>
+ *
+ * This program 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 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * Written by : William Jon McCann <mccann@jhu.edu>
+ *              Ray Strode <rstrode@redhat.com>
+ */
+
+#include "config.h"
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#include <dirent.h>
+#include <sys/stat.h>
+
+#include <glib.h>
+#include <glib/gi18n.h>
+#include <glib/gstdio.h>
+
+#include "gdm-greeter-sessions.h"
+
+typedef struct _GdmSessionFile {
+        char    *id;
+        char    *path;
+        char    *translated_name;
+        char    *translated_comment;
+} GdmSessionFile;
+
+static GHashTable *gdm_available_sessions_map;
+
+static gboolean gdm_sessions_map_is_initialized = FALSE;
+
+/* adapted from gnome-menus desktop-entries.c */
+static gboolean
+key_file_is_relevant (GKeyFile     *key_file)
+{
+        GError    *error;
+        gboolean   no_display;
+        gboolean   hidden;
+        gboolean   tryexec_failed;
+        char      *tryexec;
+
+        error = NULL;
+        no_display = g_key_file_get_boolean (key_file,
+                                             G_KEY_FILE_DESKTOP_GROUP,
+                                             "NoDisplay",
+                                             &error);
+        if (error) {
+                no_display = FALSE;
+                g_error_free (error);
+        }
+
+        error = NULL;
+        hidden = g_key_file_get_boolean (key_file,
+                                         G_KEY_FILE_DESKTOP_GROUP,
+                                         "Hidden",
+                                         &error);
+        if (error) {
+                hidden = FALSE;
+                g_error_free (error);
+        }
+
+        tryexec_failed = FALSE;
+        tryexec = g_key_file_get_string (key_file,
+                                         G_KEY_FILE_DESKTOP_GROUP,
+                                         "TryExec",
+                                         NULL);
+        if (tryexec) {
+                char *path;
+
+                path = g_find_program_in_path (g_strstrip (tryexec));
+
+                tryexec_failed = (path == NULL);
+
+                g_free (path);
+                g_free (tryexec);
+        }
+
+        if (no_display || hidden || tryexec_failed) {
+                return FALSE;
+        }
+
+        return TRUE;
+}
+
+static void
+load_session_file (const char              *id,
+                   const char              *path)
+{
+        GKeyFile          *key_file;
+        GError            *error;
+        gboolean           res;
+        GdmSessionFile    *session;
+
+        key_file = g_key_file_new ();
+
+        error = NULL;
+        res = g_key_file_load_from_file (key_file, path, 0, &error);
+
+        if (!res) {
+                g_debug ("Failed to load \"%s\": %s\n", path, error->message);
+                g_error_free (error);
+                goto out;
+        }
+
+        if (! g_key_file_has_group (key_file, G_KEY_FILE_DESKTOP_GROUP)) {
+                goto out;
+        }
+
+        res = g_key_file_has_key (key_file, G_KEY_FILE_DESKTOP_GROUP, "Name", NULL);
+        if (! res) {
+                g_debug ("\"%s\" contains no \"Name\" key\n", path);
+                goto out;
+        }
+
+        if (!key_file_is_relevant (key_file)) {
+                g_debug ("\"%s\" is hidden or contains non-executable TryExec program\n", path);
+                goto out;
+        }
+
+        session = g_new0 (GdmSessionFile, 1);
+
+        session->id = g_strdup (id);
+        session->path = g_strdup (path);
+
+        session->translated_name = g_key_file_get_locale_string (key_file, G_KEY_FILE_DESKTOP_GROUP, "Name", NULL, NULL);
+        session->translated_comment = g_key_file_get_locale_string (key_file, G_KEY_FILE_DESKTOP_GROUP, "Comment", NULL, NULL);
+
+        g_hash_table_insert (gdm_available_sessions_map,
+                             g_strdup (id),
+                             session);
+ out:
+        g_key_file_free (key_file);
+}
+
+static void
+collect_sessions_from_directory (const char *dirname)
+{
+        GDir       *dir;
+        const char *filename;
+
+        /* FIXME: add file monitor to directory */
+
+        dir = g_dir_open (dirname, 0, NULL);
+        if (dir == NULL) {
+                return;
+        }
+
+        while ((filename = g_dir_read_name (dir))) {
+                char *id;
+                char *full_path;
+
+                if (! g_str_has_suffix (filename, ".desktop")) {
+                        continue;
+                }
+                id = g_strndup (filename, strlen (filename) - strlen (".desktop"));
+
+                full_path = g_build_filename (dirname, filename, NULL);
+
+                load_session_file (id, full_path);
+
+                g_free (id);
+                g_free (full_path);
+        }
+
+        g_dir_close (dir);
+}
+
+static void
+collect_sessions (void)
+{
+        int         i;
+        const char *search_dirs[] = {
+                "/etc/X11/sessions/",
+                DMCONFDIR "/Sessions/",
+                DATADIR "/gdm/BuiltInSessions/",
+                DATADIR "/xsessions/",
+                NULL
+        };
+
+        if (gdm_available_sessions_map == NULL) {
+                gdm_available_sessions_map = g_hash_table_new_full (g_str_hash, g_str_equal,
+                                                                    g_free, g_free);
+        }
+
+        for (i = 0; search_dirs [i] != NULL; i++) {
+                collect_sessions_from_directory (search_dirs [i]);
+        }
+}
+
+/**
+ * gdm_greeter_get_session_ids:
+ *
+ * Reads /usr/share/xsessions and other relevant places for possible sessions
+ * to log into and returns the complete list.
+ *
+ * Returns: (transfer full): a %NULL terminated list of session ids
+ */
+char **
+gdm_greeter_get_session_ids (void)
+{
+        GHashTableIter iter;
+        gpointer key, value;
+        GPtrArray *array;
+
+        if (!gdm_sessions_map_is_initialized) {
+                collect_sessions ();
+
+                gdm_sessions_map_is_initialized = TRUE;
+        }
+
+        array = g_ptr_array_new ();
+        g_hash_table_iter_init (&iter, gdm_available_sessions_map);
+        while (g_hash_table_iter_next (&iter, &key, &value)) {
+                GdmSessionFile *session;
+
+                session = (GdmSessionFile *) value;
+
+                g_ptr_array_add (array, g_strdup (session->id));
+        }
+        g_ptr_array_add (array, NULL);
+
+        return (char **) g_ptr_array_free (array, FALSE);
+}
+
+/**
+ * gdm_greeter_get_session_name_and_description:
+ * @id: an id from gdm_greeter_get_session_ids()
+ * @description: (out): optional returned session description
+ *
+ * Takes an xsession id and returns the name and comment about it.
+ *
+ * Returns: The session name if found, or %NULL otherwise
+ */
+char *
+gdm_greeter_get_session_name_and_description (const char  *id,
+                                              char       **description)
+{
+        GdmSessionFile *session;
+        char *name;
+
+        if (!gdm_sessions_map_is_initialized) {
+                collect_sessions ();
+
+                gdm_sessions_map_is_initialized = TRUE;
+        }
+
+        session = (GdmSessionFile *) g_hash_table_lookup (gdm_available_sessions_map,
+                                                          id);
+
+        if (session == NULL) {
+                return NULL;
+        }
+
+        name = g_strdup (session->translated_name);
+
+        if (description != NULL) {
+                *description = g_strdup (session->translated_comment);
+        }
+
+        return name;
+}
diff --git a/gui/libgdmgreeter/gdm-greeter-sessions.h b/gui/libgdmgreeter/gdm-greeter-sessions.h
new file mode 100644
index 00000000..ab78a985
--- /dev/null
+++ b/gui/libgdmgreeter/gdm-greeter-sessions.h
@@ -0,0 +1,37 @@
+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 8 -*-
+ *
+ * Copyright 2008 Red Hat, Inc.
+ * Copyright 2007 William Jon McCann <mccann@jhu.edu>
+ *
+ * This program 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 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * Written by: Ray Strode
+ *             William Jon McCann
+ */
+
+#ifndef __GDM_GREETER_SESSIONS_H
+#define __GDM_GREETER_SESSIONS_H
+
+#include <glib.h>
+
+G_BEGIN_DECLS
+
+char **                gdm_greeter_get_session_ids (void);
+char *                 gdm_greeter_get_session_name_and_description (const char  *id,
+                                                                     char       **description);
+
+G_END_DECLS
+
+#endif /* __GDM_SESSION_H */
diff --git a/gui/libgdmgreeter/gdmgreeter.pc.in b/gui/libgdmgreeter/gdmgreeter.pc.in
new file mode 100644
index 00000000..b1c68022
--- /dev/null
+++ b/gui/libgdmgreeter/gdmgreeter.pc.in
@@ -0,0 +1,10 @@
+prefix=@prefix@
+exec_prefix=@exec_prefix@
+libdir=@libdir@
+includedir=@includedir@
+
+Name: GDM Greeter Library
+Description: Client Library for communicating with GDM greeter server
+Version: @VERSION@
+Libs: -L${libdir} -lgdmgreeter
+Cflags: -I${includedir}/gdm/greeter