Hotplug: Separate D-Bus into core and hotplug API components

Break up D-Bus into two components: a D-Bus core that can be used by any
part of the server (for the moment, just the D-Bus hotplug API, and the
forthcoming HAL hotplug API), and the old D-Bus hotplug API.

5 files changed, 719 insertions, 480 deletions

diff --git a/config/Makefile.am b/config/Makefile.am
index 43c9aa330..527034493 100644
--- a/config/Makefile.am
+++ b/config/Makefile.am
@@ -1,10 +1,19 @@
 AM_CFLAGS = @DIX_CFLAGS@
 
+noinst_LIBRARIES = libconfig.a
+libconfig_a_SOURCES = config.c
+
+if HAVE_DBUS
+AM_CFLAGS += @DBUS_CFLAGS@
+libconfig_a_SOURCES += dbus-core.c
+endif
+
+if CONFIG_DBUS_API
 dbusconfigdir = $(sysconfdir)/dbus-1/system.d
 dbusconfig_DATA = xorg-server.conf
 
 noinst_LIBRARIES = libconfig.a
-
-libconfig_a_SOURCES = config.c
+libconfig_a_SOURCES += dbus.c
+endif
 
 EXTRA_DIST = xorg-server.conf
diff --git a/config/config-backends.h b/config/config-backends.h
new file mode 100644
index 000000000..8a10a3e49
--- /dev/null
+++ b/config/config-backends.h
@@ -0,0 +1,52 @@
+/*
+ * Copyright © 2006-2007 Daniel Stone
+ *
+ * Permission to use, copy, modify, distribute, and sell this software and its
+ * documentation for any purpose is hereby granted without fee, provided that
+ * the above copyright notice appear in all copies and that both that
+ * copyright notice and this permission notice appear in supporting
+ * documentation, and that the name of the copyright holders and/or authors
+ * not be used in advertising or publicity pertaining to distribution of the
+ * software without specific, written prior permission.  The copyright holders
+ * and/or authors make no representations about the suitability of this
+ * software for any purpose.  It is provided "as is" without express or
+ * implied warranty.
+ *
+ * THE COPYRIGHT HOLDERS AND/OR AUTHORS DISCLAIM ALL WARRANTIES WITH REGARD
+ * TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS, IN NO EVENT SHALL THE COPYRIGHT HOLDERS AND/OR AUTHORS BE LIABLE
+ * FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
+ * RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF
+ * CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#ifdef HAVE_DIX_CONFIG_H
+#include <dix-config.h>
+#endif
+
+#ifdef HAVE_DBUS
+#include <dbus/dbus.h>
+
+typedef void (*config_dbus_core_connect_hook)(DBusConnection *connection,
+                                              void *data);
+typedef void (*config_dbus_core_disconnect_hook)(void *data);
+
+struct config_dbus_core_hook {
+    config_dbus_core_connect_hook connect;
+    config_dbus_core_disconnect_hook disconnect;
+    void *data;
+
+    struct config_dbus_core_hook *next;
+};
+
+int config_dbus_core_init(void);
+void config_dbus_core_fini(void);
+int config_dbus_core_add_hook(struct config_dbus_core_hook *hook);
+void config_dbus_core_remove_hook(struct config_dbus_core_hook *hook);
+#endif
+
+#ifdef CONFIG_DBUS_API
+int config_dbus_init(void);
+void config_dbus_fini(void);
+#endif
diff --git a/config/config.c b/config/config.c
index 9b38faf49..a6d36c0ee 100644
--- a/config/config.c
+++ b/config/config.c
@@ -1,5 +1,5 @@
 /*
- * Copyright © 2006 Daniel Stone
+ * Copyright © 2006-2007 Daniel Stone
  *
  * Permission to use, copy, modify, distribute, and sell this software and its
  * documentation for any purpose is hereby granted without fee, provided that
@@ -25,490 +25,28 @@
 #include <dix-config.h>
 #endif
 
-#ifdef HAVE_DBUS
-#define DBUS_API_SUBJECT_TO_CHANGE
-#include <dbus/dbus.h>
-#include <string.h>
-#include <sys/select.h>
-
-#include <X11/X.h>
-
-#include "opaque.h" /* for 'display': there has to be a better way */
-                    /* the above comment lies.  there is no better way. */
-#include "input.h"
-#include "inputstr.h"
 #include "hotplug.h"
-#include "os.h"
-
-#define CONFIG_MATCH_RULE "type='method_call',interface='org.x.config.input'"
-
-#define MALFORMED_MSG "[config] malformed message, dropping"
-#define MALFORMED_MESSAGE() { DebugF(MALFORMED_MSG "\n"); \
-                            ret = BadValue; \
-                            goto unwind; }
-#define MALFORMED_MESSAGE_ERROR() { DebugF(MALFORMED_MSG ": %s, %s", \
-                                       error->name, error->message); \
-                                  ret = BadValue; \
-                                  goto unwind; }
-
-/* How often to attempt reconnecting when we get booted off the bus. */
-#define RECONNECT_DELAY 10000 /* in ms */
-
-struct config_data {
-    int fd;
-    DBusConnection *connection;
-    char busobject[32];
-    char busname[64];
-};
-
-static struct config_data *configData;
-
-static CARD32 configReconnect(OsTimerPtr timer, CARD32 time, pointer arg);
-
-static void
-configWakeupHandler(pointer blockData, int err, pointer pReadMask)
-{
-    struct config_data *data = blockData;
-
-    if (data->connection && FD_ISSET(data->fd, (fd_set *) pReadMask))
-        dbus_connection_read_write_dispatch(data->connection, 0);
-}
-
-static void
-configBlockHandler(pointer data, struct timeval **tv, pointer pReadMask)
-{
-}
-
-static void
-configTeardown(void)
-{
-    if (configData) {
-        RemoveGeneralSocket(configData->fd);
-        RemoveBlockAndWakeupHandlers(configBlockHandler, configWakeupHandler,
-                                     configData);
-        xfree(configData);
-        configData = NULL;
-    }
-}
-
-static int
-configAddDevice(DBusMessage *message, DBusMessageIter *iter, 
-                DBusMessage *reply, DBusMessageIter *r_iter,
-                DBusError *error)
-{
-    DBusMessageIter subiter;
-    InputOption *tmpo = NULL, *options = NULL;
-    char *tmp = NULL;
-    int ret = BadMatch;
-    DeviceIntPtr dev = NULL;
-
-    DebugF("[config] adding device\n");
-
-    /* signature should be [ss][ss]... */
-    options = (InputOption *) xcalloc(sizeof(InputOption), 1);
-    if (!options) {
-        ErrorF("[config] couldn't allocate option\n");
-        return BadAlloc;
-    }
-
-    options->key = xstrdup("_source");
-    options->value = xstrdup("client/dbus");
-    if(!options->key || !options->value) {
-        ErrorF("[config] couldn't allocate first key/value pair\n");
-        ret = BadAlloc;
-        goto unwind;
-    }
-
-    while (dbus_message_iter_get_arg_type(iter) == DBUS_TYPE_ARRAY) {
-        tmpo = (InputOption *) xcalloc(sizeof(InputOption), 1);
-        if (!tmpo) {
-            ErrorF("[config] couldn't allocate option\n");
-            ret = BadAlloc;
-            goto unwind;
-        }
-        tmpo->next = options;
-        options = tmpo;
-
-        dbus_message_iter_recurse(iter, &subiter);
-
-        if (dbus_message_iter_get_arg_type(&subiter) != DBUS_TYPE_STRING)
-            MALFORMED_MESSAGE();
-
-        dbus_message_iter_get_basic(&subiter, &tmp);
-        if (!tmp)
-            MALFORMED_MESSAGE();
-        if (tmp[0] == '_') {
-            ErrorF("[config] attempted subterfuge: option name %s given\n",
-                   tmp);
-            MALFORMED_MESSAGE();
-        }
-        options->key = xstrdup(tmp);
-        if (!options->key) {
-            ErrorF("[config] couldn't duplicate key!\n");
-            ret = BadAlloc;
-            goto unwind;
-        }
-
-        if (!dbus_message_iter_has_next(&subiter))
-            MALFORMED_MESSAGE();
-        dbus_message_iter_next(&subiter);
-        if (dbus_message_iter_get_arg_type(&subiter) != DBUS_TYPE_STRING)
-            MALFORMED_MESSAGE();
-
-        dbus_message_iter_get_basic(&subiter, &tmp);
-        if (!tmp)
-            MALFORMED_MESSAGE();
-        options->value = xstrdup(tmp);
-        if (!options->value) {
-            ErrorF("[config] couldn't duplicate option!\n");
-            ret = BadAlloc;
-            goto unwind;
-        }
-
-        dbus_message_iter_next(iter);
-    }
-
-    ret = NewInputDeviceRequest(options, &dev);
-    if (ret != Success) {
-        DebugF("[config] NewInputDeviceRequest failed\n");
-        goto unwind;
-    }
-
-    if (!dev) {
-        DebugF("[config] NewInputDeviceRequest succeeded, without device\n"); 
-        ret = BadMatch;
-        goto unwind;
-    }
-
-    if (!dbus_message_iter_append_basic(r_iter, DBUS_TYPE_INT32, &(dev->id))) {
-        ErrorF("[config] couldn't append to iterator\n");
-        ret = BadAlloc;
-        goto unwind;
-    }
-
-unwind:
-    if (dev && ret != Success)
-        RemoveDevice(dev);
-
-    while (options) {
-        tmpo = options;
-        options = options->next;
-        if (tmpo->key)
-            xfree(tmpo->key);
-        if (tmpo->value)
-            xfree(tmpo->value);
-        xfree(tmpo);
-    }
-
-    return ret;
-}
-
-static int
-configRemoveDevice(DBusMessage *message, DBusMessageIter *iter,
-                   DBusError *error)
-{
-    int deviceid = -1;
-    int ret = BadMatch;
-    DeviceIntPtr pDev = NULL;
-
-    if (!dbus_message_get_args(message, error, DBUS_TYPE_INT32,
-                               &deviceid, DBUS_TYPE_INVALID)) {
-        MALFORMED_MESSAGE_ERROR();
-    }
-
-    if (deviceid < 0 || !(pDev = LookupDeviceIntRec(deviceid))) {
-        DebugF("[config] bogus device id %d given\n", deviceid);
-        ret = BadMatch;
-        goto unwind;
-    }
-
-    DebugF("[config] removing device %s (id %d)\n", pDev->name, deviceid);
-
-    /* Call PIE here so we don't try to dereference a device that's
-     * already been removed. */
-    OsBlockSignals();
-    ProcessInputEvents();
-    DeleteInputDeviceRequest(pDev);
-    OsReleaseSignals();
-
-    return Success;
-
-unwind:
-    return ret;
-}
-
-static int
-configListDevices(DBusMessage *message, DBusMessageIter *iter,
-                   DBusMessage *reply, DBusMessageIter *r_iter,
-                   DBusError *error)
-{
-    DeviceIntPtr d;
-    int ret = BadMatch;
-
-    for (d = inputInfo.devices; d; d = d->next) {
-        if (!dbus_message_iter_append_basic(r_iter, DBUS_TYPE_INT32,
-                                            &(d->id))) {
-            ErrorF("[config] couldn't append to iterator\n");
-            ret = BadAlloc;
-            goto unwind;
-        }
-        if (!dbus_message_iter_append_basic(r_iter, DBUS_TYPE_STRING,
-                                            &(d->name))) {
-            ErrorF("[config] couldn't append to iterator\n");
-            ret = BadAlloc;
-            goto unwind;
-        }
-    }
-
-unwind:
-    return ret;
-}
-
-static DBusHandlerResult
-configMessage(DBusConnection *connection, DBusMessage *message, void *closure)
-{
-    DBusMessageIter iter;
-    DBusError error;
-    DBusMessage *reply;
-    DBusMessageIter r_iter;
-    DBusConnection *bus = closure;
-    int ret = BadDrawable; /* nonsensical value */
-
-    dbus_error_init(&error);
-
-    DebugF("[config] received a message\n");
-
-    if (strcmp(dbus_message_get_interface(message),
-               "org.x.config.input") == 0) {
-
-        if (!(reply = dbus_message_new_method_return(message))) {
-            ErrorF("[config] failed to create the reply message\n");
-            dbus_error_free(&error);
-            return DBUS_HANDLER_RESULT_NEED_MEMORY;
-        }
-        dbus_message_iter_init_append(reply, &r_iter);
-
-        /* listDevices doesn't take any arguments */
-        if (strcmp(dbus_message_get_member(message), "listDevices") == 0)
-            ret = configListDevices(message, NULL, reply, &r_iter, &error);
-        else 
-        {
-            if (!dbus_message_iter_init(message, &iter)) {
-                ErrorF("[config] failed to init iterator\n");
-                dbus_message_unref(reply);
-                dbus_error_free(&error);
-                return DBUS_HANDLER_RESULT_NEED_MEMORY; /* ?? */
-            }
-
-            if (strcmp(dbus_message_get_member(message), "add") == 0)
-                ret = configAddDevice(message, &iter, reply, &r_iter, &error);
-            else if (strcmp(dbus_message_get_member(message), "remove") == 0)
-                ret = configRemoveDevice(message, &iter, &error);
-        }
-
-        if (ret != BadDrawable && ret != BadAlloc) {
-            if (!strlen(dbus_message_get_signature(reply)))
-            {
-                ret = -ret; /* return errors as negative numbers */
-                if (!dbus_message_iter_append_basic(&r_iter, DBUS_TYPE_INT32, &ret)) {
-                    ErrorF("[config] couldn't append to iterator\n");
-                    dbus_message_unref(reply);
-                    dbus_error_free(&error);
-                    return DBUS_HANDLER_RESULT_HANDLED;
-                }
-            }
-
-            if (!dbus_connection_send(bus, reply, NULL))
-                ErrorF("[config] failed to send reply\n");
-        }
-        dbus_message_unref(reply);
-        dbus_connection_flush(bus);
-    }
-
-    dbus_error_free(&error);
-
-    if (ret == BadAlloc)
-        return DBUS_HANDLER_RESULT_NEED_MEMORY;
-    else if (ret == BadDrawable)
-        return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
-    else
-        return DBUS_HANDLER_RESULT_HANDLED;
-}
-
-/**
- * This is a filter, which only handles the disconnected signal, which
- * doesn't go to the normal message handling function.  This takes
- * precedence over the message handling function, so have have to be
- * careful to ignore anything we don't want to deal with here.
- *
- * Yes, this is brutally stupid.
- */
-static DBusHandlerResult
-configFilter(DBusConnection *connection, DBusMessage *message, void *closure)
-{
-    if (dbus_message_is_signal(message, DBUS_INTERFACE_LOCAL,
-                                    "Disconnected")) {
-        ErrorF("[dbus] disconnected from bus\n");
-        TimerSet(NULL, 0, RECONNECT_DELAY, configReconnect, NULL);
-        configTeardown();
-        return DBUS_HANDLER_RESULT_HANDLED;
-    }
-
-    return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
-}
-
-static Bool
-configSetup(void)
-{
-    DBusError error;
-    DBusObjectPathVTable vtable = { .message_function = configMessage };
-
-    if (!configData)
-        configData = (struct config_data *) xcalloc(sizeof(struct config_data), 1);
-    if (!configData) {
-        ErrorF("[dbus] failed to allocate data struct\n");
-        return FALSE;
-    }
-
-    dbus_error_init(&error);
-    configData->connection = dbus_bus_get(DBUS_BUS_SYSTEM, &error);
-    if (!configData->connection || dbus_error_is_set(&error)) {
-        DebugF("[dbus] some kind of error occurred while connecting: %s (%s)\n",
-               error.name, error.message);
-        dbus_error_free(&error);
-        xfree(configData);
-        configData = NULL;
-        return FALSE;
-    }
-
-    dbus_connection_set_exit_on_disconnect(configData->connection, FALSE);
-
-    if (!dbus_connection_get_unix_fd(configData->connection, &configData->fd)) {
-        dbus_connection_unref(configData->connection);
-        ErrorF("[dbus] couldn't get fd for bus\n");
-        dbus_error_free(&error);
-        xfree(configData);
-        configData = NULL;
-        return FALSE;
-    }
-
-    snprintf(configData->busname, sizeof(configData->busname),
-             "org.x.config.display%d", atoi(display));
-    if (!dbus_bus_request_name(configData->connection, configData->busname,
-                               0, &error) || dbus_error_is_set(&error)) {
-        ErrorF("[dbus] couldn't take over org.x.config: %s (%s)\n",
-               error.name, error.message);
-        dbus_error_free(&error);
-        dbus_connection_unref(configData->connection);
-        xfree(configData);
-        configData = NULL;
-        return FALSE;
-    }
-
-    /* blocks until we get a reply. */
-    dbus_bus_add_match(configData->connection, CONFIG_MATCH_RULE, &error);
-    if (dbus_error_is_set(&error)) {
-        ErrorF("[dbus] couldn't match X.Org rule: %s (%s)\n", error.name,
-               error.message);
-        dbus_error_free(&error);
-        dbus_bus_release_name(configData->connection, configData->busname,
-                              &error);
-        dbus_connection_unref(configData->connection);
-        xfree(configData);
-        configData = NULL;
-        return FALSE;
-    }
-
-    if (!dbus_connection_add_filter(configData->connection, configFilter,
-                                    configData, NULL)) {
-
-        ErrorF("[dbus] couldn't add signal filter: %s (%s)\n", error.name,
-               error.message);
-        dbus_error_free(&error);
-        dbus_bus_release_name(configData->connection, configData->busname,
-                              &error);
-        dbus_bus_remove_match(configData->connection, CONFIG_MATCH_RULE,
-                              &error);
-        dbus_connection_unref(configData->connection);
-        xfree(configData);
-        configData = NULL;
-        return FALSE;
-    }
-
-    snprintf(configData->busobject, sizeof(configData->busobject),
-             "/org/x/config/%d", atoi(display));
-    if (!dbus_connection_register_object_path(configData->connection,
-                                              configData->busobject, &vtable,
-                                              configData->connection)) {
-        ErrorF("[dbus] couldn't register object path\n");
-        dbus_bus_release_name(configData->connection, configData->busname,
-                              &error);
-        dbus_bus_remove_match(configData->connection, CONFIG_MATCH_RULE,
-                              &error);
-        dbus_connection_unref(configData->connection);
-        dbus_error_free(&error);
-        xfree(configData);
-        configData = NULL;
-        return FALSE;
-    }
-
-    DebugF("[dbus] registered object path %s\n", configData->busobject);
-
-    dbus_error_free(&error);
-    AddGeneralSocket(configData->fd);
-
-    RegisterBlockAndWakeupHandlers(configBlockHandler, configWakeupHandler,
-                                   configData);
-
-    return TRUE;
-}
-
-static CARD32
-configReconnect(OsTimerPtr timer, CARD32 time, pointer arg)
-{
-    if (configSetup())
-        return 0;
-    else
-        return RECONNECT_DELAY;
-}
-
-void
-configInitialise(void)
-{
-    TimerSet(NULL, 0, 1, configReconnect, NULL);
-}
+#include "config-backends.h"
 
 void
-configFini(void)
+config_init()
 {
-    DBusError error;
-
-    if (configData) {
-        dbus_error_init(&error);
-        dbus_connection_unregister_object_path(configData->connection,
-                                               configData->busobject);
-        dbus_connection_remove_filter(configData->connection, configFilter,
-                                      configData);
-        dbus_bus_remove_match(configData->connection, CONFIG_MATCH_RULE,
-                              &error);
-        dbus_bus_release_name(configData->connection, configData->busname,
-                              &error);
-        dbus_connection_unref(configData->connection);
-        dbus_error_free(&error);
-        configTeardown();
+#if defined(CONFIG_DBUS_API)
+    if (config_dbus_core_init()) {
+       if (!config_dbus_init())
+	    ErrorF("[config] failed to initialise D-Bus API\n");
     }
-}
-
-#else /* !HAVE_DBUS */
-
-void
-configInitialise()
-{
+    else {
+	ErrorF("[config] failed to initialise D-Bus core\n");
+    }
+#endif
 }
 
 void
-configFini()
+config_fini()
 {
+#if defined(CONFIG_DBUS_API)
+    config_dbus_fini();
+    config_dbus_core_fini();
+#endif
 }
-
-#endif /* HAVE_DBUS */
diff --git a/config/dbus-core.c b/config/dbus-core.c
new file mode 100644
index 000000000..b90e413f3
--- /dev/null
+++ b/config/dbus-core.c
@@ -0,0 +1,233 @@
+/*
+ * Copyright © 2006-2007 Daniel Stone
+ *
+ * Permission to use, copy, modify, distribute, and sell this software and its
+ * documentation for any purpose is hereby granted without fee, provided that
+ * the above copyright notice appear in all copies and that both that
+ * copyright notice and this permission notice appear in supporting
+ * documentation, and that the name of the copyright holders and/or authors
+ * not be used in advertising or publicity pertaining to distribution of the
+ * software without specific, written prior permission.  The copyright holders
+ * and/or authors make no representations about the suitability of this
+ * software for any purpose.  It is provided "as is" without express or
+ * implied warranty.
+ *
+ * THE COPYRIGHT HOLDERS AND/OR AUTHORS DISCLAIM ALL WARRANTIES WITH REGARD
+ * TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS, IN NO EVENT SHALL THE COPYRIGHT HOLDERS AND/OR AUTHORS BE LIABLE
+ * FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
+ * RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF
+ * CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#ifdef HAVE_DIX_CONFIG_H
+#include <dix-config.h>
+#endif
+
+#define DBUS_API_SUBJECT_TO_CHANGE
+#include <dbus/dbus.h>
+#include <sys/select.h>
+
+#include "config-backends.h"
+#include "dix.h"
+#include "os.h"
+
+/* How often to attempt reconnecting when we get booted off the bus. */
+#define RECONNECT_DELAY (10 * 1000) /* in ms */
+
+struct dbus_core_info {
+    int fd;
+    DBusConnection *connection;
+    OsTimerPtr timer;
+    struct config_dbus_core_hook *hooks;
+};
+static struct dbus_core_info bus_info;
+
+static CARD32 reconnect_timer(OsTimerPtr timer, CARD32 time, pointer arg);
+
+static void
+wakeup_handler(pointer data, int err, pointer read_mask)
+{
+    struct dbus_core_info *info = data;
+
+    if (info->connection && FD_ISSET(info->fd, (fd_set *) read_mask))
+        dbus_connection_read_write_dispatch(info->connection, 0);
+}
+
+static void
+block_handler(pointer data, struct timeval **tv, pointer read_mask)
+{
+}
+
+/**
+ * Disconnect (if we haven't already been forcefully disconnected), clean up
+ * after ourselves, and call all registered disconnect hooks.
+ */
+static void
+teardown(void)
+{
+    struct config_dbus_core_hook *hook;
+
+    if (bus_info.timer) {
+        TimerCancel(bus_info.timer);
+        bus_info.timer = NULL;
+    }
+
+    /* We should really have pre-disconnect hooks and run them here, for
+     * completeness.  But then it gets awkward, given that you can't
+     * guarantee that they'll be called ... */
+    if (bus_info.connection)
+        dbus_connection_unref(bus_info.connection);
+
+    RemoveBlockAndWakeupHandlers(block_handler, wakeup_handler, &bus_info);
+    RemoveGeneralSocket(bus_info.fd);
+    bus_info.fd = -1;
+    bus_info.connection = NULL;
+
+    for (hook = bus_info.hooks; hook; hook = hook->next) {
+        if (hook->disconnect)
+            hook->disconnect(hook->data);
+    }
+}
+
+/**
+ * This is a filter, which only handles the disconnected signal, which
+ * doesn't go to the normal message handling function.  This takes
+ * precedence over the message handling function, so have have to be
+ * careful to ignore anything we don't want to deal with here.
+ */
+static DBusHandlerResult
+message_filter(DBusConnection *connection, DBusMessage *message, void *data)
+{
+    /* If we get disconnected, then take everything down, and attempt to
+     * reconnect immediately (assuming it's just a restart).  The
+     * connection isn't valid at this point, so throw it out immediately. */
+    if (dbus_message_is_signal(message, DBUS_INTERFACE_LOCAL,
+                                    "Disconnected")) {
+        DebugF("[config/dbus-core] disconnected from bus\n");
+        bus_info.connection = NULL;
+        teardown();
+
+        bus_info.timer = TimerSet(NULL, 0, 1, reconnect_timer, NULL);
+
+        return DBUS_HANDLER_RESULT_HANDLED;
+    }
+
+    return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
+}
+
+/**
+ * Attempt to connect to the system bus, and set a filter to deal with
+ * disconnection (see message_filter above).
+ *
+ * @return 1 on success, 0 on failure.
+ */
+static int
+connect_to_bus(void)
+{
+    DBusError error;
+    struct config_dbus_core_hook *hook;
+
+    dbus_error_init(&error);
+    bus_info.connection = dbus_bus_get(DBUS_BUS_SYSTEM, &error);
+    if (!bus_info.connection || dbus_error_is_set(&error)) {
+        DebugF("[config/dbus-core] error connecting to system bus: %s (%s)\n",
+               error.name, error.message);
+        goto err_begin;
+    }
+
+    /* Thankyou.  Really, thankyou. */
+    dbus_connection_set_exit_on_disconnect(bus_info.connection, FALSE);
+
+    if (!dbus_connection_get_unix_fd(bus_info.connection, &bus_info.fd)) {
+        ErrorF("[config/dbus-core] couldn't get fd for system bus\n");
+        goto err_unref;
+    }
+
+    if (!dbus_connection_add_filter(bus_info.connection, message_filter,
+                                    &bus_info, NULL)) {
+        ErrorF("[config/dbus-core] couldn't add filter: %s (%s)\n", error.name,
+               error.message);
+        goto err_fd;
+    }
+
+    dbus_error_free(&error);
+    AddGeneralSocket(bus_info.fd);
+
+    RegisterBlockAndWakeupHandlers(block_handler, wakeup_handler, &bus_info);
+
+    for (hook = bus_info.hooks; hook; hook = hook->next) {
+        if (hook->connect)
+            hook->connect(bus_info.connection, hook->data);
+    }
+
+    return 1;
+
+err_fd:
+    bus_info.fd = -1;
+err_unref:
+    dbus_connection_unref(bus_info.connection);
+    bus_info.connection = NULL;
+err_begin:
+    dbus_error_free(&error);
+
+    return 0;
+}
+
+static CARD32
+reconnect_timer(OsTimerPtr timer, CARD32 time, pointer arg)
+{
+    if (connect_to_bus()) {
+        bus_info.timer = NULL;
+        return 0;
+    }
+    else {
+        return RECONNECT_DELAY;
+    }
+}
+
+int
+config_dbus_core_add_hook(struct config_dbus_core_hook *hook)
+{
+    struct config_dbus_core_hook **prev;
+
+    for (prev = &bus_info.hooks; *prev; prev = &(*prev)->next)
+        ;
+    *prev = hook;
+
+    /* If we're already connected, call the connect hook. */
+    if (bus_info.connection)
+        hook->connect(bus_info.connection, hook->data);
+
+    return 1;
+}
+
+void
+config_dbus_core_remove_hook(struct config_dbus_core_hook *hook)
+{
+    struct config_dbus_core_hook **prev;
+
+    for (prev = &bus_info.hooks; *prev; prev = &(*prev)->next) {
+        if (*prev == hook)
+            *prev = hook->next;
+    }
+}
+
+int
+config_dbus_core_init(void)
+{
+    memset(&bus_info, 0, sizeof(bus_info));
+    bus_info.fd = -1;
+    bus_info.hooks = NULL;
+    bus_info.connection = NULL;
+    bus_info.timer = TimerSet(NULL, 0, 1, reconnect_timer, NULL);
+
+    return 1;
+}
+
+void
+config_dbus_core_fini(void)
+{
+    teardown();
+}
diff --git a/config/dbus.c b/config/dbus.c
new file mode 100644
index 000000000..2450e0c00
--- /dev/null
+++ b/config/dbus.c
@@ -0,0 +1,407 @@
+/*
+ * Copyright © 2006-2007 Daniel Stone
+ *
+ * Permission to use, copy, modify, distribute, and sell this software and its
+ * documentation for any purpose is hereby granted without fee, provided that
+ * the above copyright notice appear in all copies and that both that
+ * copyright notice and this permission notice appear in supporting
+ * documentation, and that the name of the copyright holders and/or authors
+ * not be used in advertising or publicity pertaining to distribution of the
+ * software without specific, written prior permission.  The copyright holders
+ * and/or authors make no representations about the suitability of this
+ * software for any purpose.  It is provided "as is" without express or
+ * implied warranty.
+ *
+ * THE COPYRIGHT HOLDERS AND/OR AUTHORS DISCLAIM ALL WARRANTIES WITH REGARD
+ * TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS, IN NO EVENT SHALL THE COPYRIGHT HOLDERS AND/OR AUTHORS BE LIABLE
+ * FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
+ * RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF
+ * CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#ifdef HAVE_DIX_CONFIG_H
+#include <dix-config.h>
+#endif
+
+#define DBUS_API_SUBJECT_TO_CHANGE
+#include <dbus/dbus.h>
+#include <string.h>
+
+#include <X11/X.h>
+
+#include "config-backends.h"
+#include "opaque.h" /* for 'display': there should be a better way. */
+#include "input.h"
+#include "inputstr.h"
+
+#define API_VERSION 1
+
+#define MATCH_RULE "type='method_call',interface='org.x.config.input'"
+
+#define MALFORMED_MSG "[config/dbus] malformed message, dropping"
+#define MALFORMED_MESSAGE() { DebugF(MALFORMED_MSG "\n"); \
+                            ret = BadValue; \
+                            goto unwind; }
+#define MALFORMED_MESSAGE_ERROR() { DebugF(MALFORMED_MSG ": %s, %s", \
+                                       error->name, error->message); \
+                                  ret = BadValue; \
+                                  goto unwind; }
+
+struct connection_info {
+    char busobject[32];
+    char busname[64];
+    DBusConnection *connection;
+};
+
+static void
+reset_info(struct connection_info *info)
+{
+    info->connection = NULL;
+    info->busname[0] = '\0';
+    info->busobject[0] = '\0';
+}
+
+static int
+add_device(DBusMessage *message, DBusMessage *reply, DBusError *error)
+{
+    DBusMessageIter iter, reply_iter, subiter;
+    InputOption *tmpo = NULL, *options = NULL;
+    char *tmp = NULL;
+    int ret, err;
+    DeviceIntPtr dev = NULL;
+
+    if (!dbus_message_iter_init(message, &iter)) {
+        ErrorF("[config/dbus] couldn't initialise iterator\n");
+        return BadAlloc;
+    }
+    dbus_message_iter_init_append(reply, &reply_iter);
+
+    options = xcalloc(sizeof(*options), 1);
+    if (!options) {
+        ErrorF("[config/dbus] couldn't allocate option\n");
+        return BadAlloc;
+    }
+
+    options->key = xstrdup("_source");
+    options->value = xstrdup("client/dbus");
+    if (!options->key || !options->value) {
+        ErrorF("[config/dbus] couldn't allocate first key/value pair\n");
+        ret = BadAlloc;
+        goto unwind;
+    }
+
+    /* signature should be [ss][ss]... */
+    while (dbus_message_iter_get_arg_type(&iter) == DBUS_TYPE_ARRAY) {
+        tmpo = xcalloc(sizeof(*tmpo), 1);
+        if (!tmpo) {
+            ErrorF("[config/dbus] couldn't allocate option\n");
+            ret = BadAlloc;
+            goto unwind;
+        }
+        tmpo->next = options;
+        options = tmpo;
+
+        dbus_message_iter_recurse(&iter, &subiter);
+
+        if (dbus_message_iter_get_arg_type(&subiter) != DBUS_TYPE_STRING)
+            MALFORMED_MESSAGE();
+
+        dbus_message_iter_get_basic(&subiter, &tmp);
+        if (!tmp)
+            MALFORMED_MESSAGE();
+        /* The _ prefix refers to internal settings, and may not be given by
+         * the client. */
+        if (tmp[0] == '_') {
+            ErrorF("[config/dbus] attempted subterfuge: option name %s given\n",
+                   tmp);
+            MALFORMED_MESSAGE();
+        }
+        options->key = xstrdup(tmp);
+        if (!options->key) {
+            ErrorF("[config/dbus] couldn't duplicate key!\n");
+            ret = BadAlloc;
+            goto unwind;
+        }
+
+        if (!dbus_message_iter_has_next(&subiter))
+            MALFORMED_MESSAGE();
+        dbus_message_iter_next(&subiter);
+        if (dbus_message_iter_get_arg_type(&subiter) != DBUS_TYPE_STRING)
+            MALFORMED_MESSAGE();
+
+        dbus_message_iter_get_basic(&subiter, &tmp);
+        if (!tmp)
+            MALFORMED_MESSAGE();
+        options->value = xstrdup(tmp);
+        if (!options->value) {
+            ErrorF("[config] couldn't duplicate option!\n");
+            ret = BadAlloc;
+            goto unwind;
+        }
+
+        dbus_message_iter_next(&iter);
+    }
+
+    ret = NewInputDeviceRequest(options, &dev);
+    if (ret != Success) {
+        DebugF("[config/dbus] NewInputDeviceRequest failed\n");
+        goto unwind;
+    }
+
+    if (!dev) {
+        DebugF("[config/dbus] NewInputDeviceRequest provided no device\n");
+        ret = BadImplementation;
+        goto unwind;
+    }
+
+    if (!dbus_message_iter_append_basic(&reply_iter, DBUS_TYPE_INT32,
+                                        &dev->id)) {
+        ErrorF("[config/dbus] couldn't append to iterator\n");
+        ret = BadAlloc;
+        goto unwind;
+    }
+
+unwind:
+    if (ret != Success) {
+        if (dev)
+            RemoveDevice(dev);
+
+        err = -ret;
+        dbus_message_iter_append_basic(&reply_iter, DBUS_TYPE_INT32, &err);
+    }
+
+    while (options) {
+        tmpo = options;
+        options = options->next;
+        if (tmpo->key)
+            xfree(tmpo->key);
+        if (tmpo->value)
+            xfree(tmpo->value);
+        xfree(tmpo);
+    }
+
+    return ret;
+}
+
+static int
+remove_device(DBusMessage *message, DBusMessage *reply, DBusError *error)
+{
+    int deviceid, ret, err;
+    DeviceIntPtr dev;
+    DBusMessageIter iter, reply_iter;
+
+    if (!dbus_message_iter_init(message, &iter)) {
+        ErrorF("[config] failed to init iterator\n");
+        return BadAlloc;
+    }
+    dbus_message_iter_init_append(reply, &reply_iter);
+
+    if (!dbus_message_get_args(message, error, DBUS_TYPE_INT32,
+                               &deviceid, DBUS_TYPE_INVALID)) {
+        MALFORMED_MESSAGE_ERROR();
+    }
+
+    dev = LookupDeviceIntRec(deviceid);
+    if (!dev) {
+        DebugF("[config] bogus device id %d given\n", deviceid);
+        ret = BadMatch;
+        goto unwind;
+    }
+
+    DebugF("[config] removing device %s (id %d)\n", dev->name, deviceid);
+
+    /* Call PIE here so we don't try to dereference a device that's
+     * already been removed. */
+    OsBlockSignals();
+    ProcessInputEvents();
+    DeleteInputDeviceRequest(dev);
+    OsReleaseSignals();
+
+    ret = Success;
+
+unwind:
+    err = (ret == Success) ? ret : -ret;
+    dbus_message_iter_append_basic(&reply_iter, DBUS_TYPE_INT32, &err);
+
+    return ret;
+}
+
+static int
+list_devices(DBusMessage *message, DBusMessage *reply, DBusError *error)
+{
+    DeviceIntPtr dev;
+    DBusMessageIter iter;
+
+    dbus_message_iter_init_append(reply, &iter);
+
+    for (dev = inputInfo.devices; dev; dev = dev->next) {
+        if (!dbus_message_iter_append_basic(&iter, DBUS_TYPE_INT32,
+                                            &dev->id)) {
+            ErrorF("[config/dbus] couldn't append to iterator\n");
+            return BadAlloc;
+        }
+        if (!dbus_message_iter_append_basic(&iter, DBUS_TYPE_STRING,
+                                            &dev->name)) {
+            ErrorF("[config/dbus] couldn't append to iterator\n");
+            return BadAlloc;
+        }
+    }
+
+    return Success;
+}
+
+static DBusHandlerResult
+message_handler(DBusConnection *connection, DBusMessage *message, void *data)
+{
+    DBusError error;
+    DBusMessage *reply;
+    struct connection_info *info = data;
+
+    /* ret is the overall D-Bus handler result, whereas err is the internal
+     * X error from our individual functions. */
+    int ret = DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
+    int err;
+
+    DebugF("[config/dbus] received a message for %s\n",
+           dbus_message_get_interface(message));
+
+    dbus_error_init(&error);
+
+    reply = dbus_message_new_method_return(message);
+    if (!reply) {
+        ErrorF("[config/dbus] failed to create reply\n");
+        ret = DBUS_HANDLER_RESULT_NEED_MEMORY;
+        goto err_start;
+    }
+
+    if (strcmp(dbus_message_get_member(message), "add") == 0)
+        err = add_device(message, reply, &error);
+    else if (strcmp(dbus_message_get_member(message), "remove") == 0)
+        err = remove_device(message, reply, &error);
+    else if (strcmp(dbus_message_get_member(message), "listDevices") == 0)
+        err = list_devices(message, reply, &error);
+    else
+        goto err_reply;
+
+    /* Failure to allocate is a special case. */
+    if (err == BadAlloc) {
+        ret = DBUS_HANDLER_RESULT_NEED_MEMORY;
+        goto err_reply;
+    }
+
+    /* While failure here is always an OOM, we don't return that,
+     * since that would result in devices being double-added/removed. */
+    if (dbus_connection_send(info->connection, reply, NULL))
+        dbus_connection_flush(info->connection);
+    else
+        ErrorF("[config/dbus] failed to send reply\n");
+
+    ret = DBUS_HANDLER_RESULT_HANDLED;
+
+err_reply:
+    dbus_message_unref(reply);
+err_start:
+    dbus_error_free(&error);
+
+    return ret;
+}
+
+static void
+connect_hook(DBusConnection *connection, void *data)
+{
+    DBusError error;
+    DBusObjectPathVTable vtable = { .message_function = message_handler, };
+    struct connection_info *info = data;
+
+    info->connection = connection;
+
+    dbus_error_init(&error);
+
+    if (!dbus_bus_request_name(info->connection, info->busname,
+                               0, &error)) {
+        ErrorF("[config/dbus] couldn't take over org.x.config: %s (%s)\n",
+               error.name, error.message);
+        goto err_start;
+    }
+
+    /* blocks until we get a reply. */
+    dbus_bus_add_match(info->connection, MATCH_RULE, &error);
+    if (dbus_error_is_set(&error)) {
+        ErrorF("[config/dbus] couldn't add match: %s (%s)\n", error.name,
+               error.message);
+        goto err_name;
+    }
+
+    if (!dbus_connection_register_object_path(info->connection,
+                                              info->busobject, &vtable,
+                                              info)) {
+        ErrorF("[config/dbus] couldn't register object path\n");
+        goto err_match;
+    }
+
+    DebugF("[dbus] registered %s, %s\n", info->busname, info->busobject);
+
+    dbus_error_free(&error);
+
+    return;
+
+err_match:
+    dbus_bus_remove_match(info->connection, MATCH_RULE, &error);
+err_name:
+    dbus_bus_release_name(info->connection, info->busname, &error);
+err_start:
+    dbus_error_free(&error);
+
+    reset_info(info);
+}
+
+static void
+disconnect_hook(void *data)
+{
+    struct connection_info *info = data;
+
+    reset_info(info);
+}
+
+#if 0
+void
+pre_disconnect_hook(void)
+{
+    DBusError error;
+
+    dbus_error_init(&error);
+    dbus_connection_unregister_object_path(connection_data->connection,
+                                           connection_data->busobject);
+    dbus_bus_remove_match(connection_data->connection, MATCH_RULE,
+                          &error);
+    dbus_bus_release_name(connection_data->connection,
+                          connection_data->busname, &error);
+    dbus_error_free(&error);
+}
+#endif
+
+static struct connection_info connection_data;
+static struct config_dbus_core_hook core_hook = {
+    .connect = connect_hook,
+    .disconnect = disconnect_hook,
+    .data = &connection_data,
+};
+
+int
+config_dbus_init(void)
+{
+    snprintf(connection_data.busname, sizeof(connection_data.busname),
+             "org.x.config.display%d", atoi(display));
+    snprintf(connection_data.busobject, sizeof(connection_data.busobject),
+             "/org/x/config/%d", atoi(display));
+
+    return config_dbus_core_add_hook(&core_hook);
+}
+
+void
+config_dbus_fini(void)
+{
+    config_dbus_core_remove_hook(&core_hook);
+}