ui: add a D-Bus display backend

The "dbus" display backend exports the QEMU consoles and other
UI-related interfaces over D-Bus.

By default, the connection is established on the session bus, but you
can specify a different bus with the "addr" option.

The backend takes the "org.qemu" service name, while still allowing
further instances to queue on the same name (so you can lookup all the
available instances too). It accepts any number of clients at this
point, although this is expected to evolve with options to restrict
clients, or only accept p2p via fd passing.

The interface is intentionally very close to the internal QEMU API,
and can be introspected or interacted with busctl/dfeet etc:

$ ./qemu-system-x86_64 -name MyVM -display dbus
$ busctl --user introspect org.qemu /org/qemu/Display1/Console_0

org.qemu.Display1.Console           interface -         -               -
.RegisterListener                   method    h         -               -
.SetUIInfo                          method    qqiiuu    -               -
.DeviceAddress                      property  s         "pci/0000/01.0" emits-change
.Head                               property  u         0               emits-change
.Height                             property  u         480             emits-change
.Label                              property  s         "VGA"           emits-change
.Type                               property  s         "Graphic"       emits-change
.Width                              property  u         640             emits-change
[...]

See the interfaces XML source file and Sphinx docs for the generated API
documentations.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>

1 files changed, 497 insertions, 0 deletions

diff --git a/ui/dbus-console.c b/ui/dbus-console.c
new file mode 100644
index 0000000..1ccf638
--- /dev/null
+++ b/ui/dbus-console.c
@@ -0,0 +1,497 @@
+/*
+ * QEMU DBus display console
+ *
+ * Copyright (c) 2021 Marc-André Lureau <marcandre.lureau@redhat.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+#include "qemu/osdep.h"
+#include "qapi/error.h"
+#include "ui/input.h"
+#include "ui/kbd-state.h"
+#include "trace.h"
+
+#include <gio/gunixfdlist.h>
+
+#include "dbus.h"
+
+struct _DBusDisplayConsole {
+    GDBusObjectSkeleton parent_instance;
+    DisplayChangeListener dcl;
+
+    DBusDisplay *display;
+    QemuConsole *con;
+    GHashTable *listeners;
+    QemuDBusDisplay1Console *iface;
+
+    QemuDBusDisplay1Keyboard *iface_kbd;
+    QKbdState *kbd;
+
+    QemuDBusDisplay1Mouse *iface_mouse;
+    gboolean last_set;
+    guint last_x;
+    guint last_y;
+    Notifier mouse_mode_notifier;
+};
+
+G_DEFINE_TYPE(DBusDisplayConsole,
+              dbus_display_console,
+              G_TYPE_DBUS_OBJECT_SKELETON)
+
+static void
+dbus_display_console_set_size(DBusDisplayConsole *ddc,
+                              uint32_t width, uint32_t height)
+{
+    g_object_set(ddc->iface,
+                 "width", width,
+                 "height", height,
+                 NULL);
+}
+
+static void
+dbus_gfx_switch(DisplayChangeListener *dcl,
+                struct DisplaySurface *new_surface)
+{
+    DBusDisplayConsole *ddc = container_of(dcl, DBusDisplayConsole, dcl);
+
+    dbus_display_console_set_size(ddc,
+                                  surface_width(new_surface),
+                                  surface_height(new_surface));
+}
+
+static void
+dbus_gfx_update(DisplayChangeListener *dcl,
+                int x, int y, int w, int h)
+{
+}
+
+static void
+dbus_gl_scanout_disable(DisplayChangeListener *dcl)
+{
+}
+
+static void
+dbus_gl_scanout_texture(DisplayChangeListener *dcl,
+                        uint32_t tex_id,
+                        bool backing_y_0_top,
+                        uint32_t backing_width,
+                        uint32_t backing_height,
+                        uint32_t x, uint32_t y,
+                        uint32_t w, uint32_t h)
+{
+    DBusDisplayConsole *ddc = container_of(dcl, DBusDisplayConsole, dcl);
+
+    dbus_display_console_set_size(ddc, w, h);
+}
+
+static void
+dbus_gl_scanout_dmabuf(DisplayChangeListener *dcl,
+                       QemuDmaBuf *dmabuf)
+{
+    DBusDisplayConsole *ddc = container_of(dcl, DBusDisplayConsole, dcl);
+
+    dbus_display_console_set_size(ddc,
+                                  dmabuf->width,
+                                  dmabuf->height);
+}
+
+static void
+dbus_gl_scanout_update(DisplayChangeListener *dcl,
+                       uint32_t x, uint32_t y,
+                       uint32_t w, uint32_t h)
+{
+}
+
+static const DisplayChangeListenerOps dbus_console_dcl_ops = {
+    .dpy_name                = "dbus-console",
+    .dpy_gfx_switch          = dbus_gfx_switch,
+    .dpy_gfx_update          = dbus_gfx_update,
+    .dpy_gl_scanout_disable  = dbus_gl_scanout_disable,
+    .dpy_gl_scanout_texture  = dbus_gl_scanout_texture,
+    .dpy_gl_scanout_dmabuf   = dbus_gl_scanout_dmabuf,
+    .dpy_gl_update           = dbus_gl_scanout_update,
+};
+
+static void
+dbus_display_console_init(DBusDisplayConsole *object)
+{
+    DBusDisplayConsole *ddc = DBUS_DISPLAY_CONSOLE(object);
+
+    ddc->listeners = g_hash_table_new_full(g_str_hash, g_str_equal,
+                                            NULL, g_object_unref);
+    ddc->dcl.ops = &dbus_console_dcl_ops;
+}
+
+static void
+dbus_display_console_dispose(GObject *object)
+{
+    DBusDisplayConsole *ddc = DBUS_DISPLAY_CONSOLE(object);
+
+    unregister_displaychangelistener(&ddc->dcl);
+    g_clear_object(&ddc->iface_kbd);
+    g_clear_object(&ddc->iface);
+    g_clear_pointer(&ddc->listeners, g_hash_table_unref);
+    g_clear_pointer(&ddc->kbd, qkbd_state_free);
+
+    G_OBJECT_CLASS(dbus_display_console_parent_class)->dispose(object);
+}
+
+static void
+dbus_display_console_class_init(DBusDisplayConsoleClass *klass)
+{
+    GObjectClass *gobject_class = G_OBJECT_CLASS(klass);
+
+    gobject_class->dispose = dbus_display_console_dispose;
+}
+
+static void
+listener_vanished_cb(DBusDisplayListener *listener)
+{
+    DBusDisplayConsole *ddc = dbus_display_listener_get_console(listener);
+    const char *name = dbus_display_listener_get_bus_name(listener);
+
+    trace_dbus_listener_vanished(name);
+
+    g_hash_table_remove(ddc->listeners, name);
+    qkbd_state_lift_all_keys(ddc->kbd);
+}
+
+static gboolean
+dbus_console_set_ui_info(DBusDisplayConsole *ddc,
+                         GDBusMethodInvocation *invocation,
+                         guint16 arg_width_mm,
+                         guint16 arg_height_mm,
+                         gint arg_xoff,
+                         gint arg_yoff,
+                         guint arg_width,
+                         guint arg_height)
+{
+    QemuUIInfo info = {
+        .width_mm = arg_width_mm,
+        .height_mm = arg_height_mm,
+        .xoff = arg_xoff,
+        .yoff = arg_yoff,
+        .width = arg_width,
+        .height = arg_height,
+    };
+
+    if (!dpy_ui_info_supported(ddc->con)) {
+        g_dbus_method_invocation_return_error(invocation,
+                                              DBUS_DISPLAY_ERROR,
+                                              DBUS_DISPLAY_ERROR_UNSUPPORTED,
+                                              "SetUIInfo is not supported");
+        return DBUS_METHOD_INVOCATION_HANDLED;
+    }
+
+    dpy_set_ui_info(ddc->con, &info, false);
+    qemu_dbus_display1_console_complete_set_uiinfo(ddc->iface, invocation);
+    return DBUS_METHOD_INVOCATION_HANDLED;
+}
+
+static gboolean
+dbus_console_register_listener(DBusDisplayConsole *ddc,
+                               GDBusMethodInvocation *invocation,
+                               GUnixFDList *fd_list,
+                               GVariant *arg_listener)
+{
+    const char *sender = g_dbus_method_invocation_get_sender(invocation);
+    GDBusConnection *listener_conn;
+    g_autoptr(GError) err = NULL;
+    g_autoptr(GSocket) socket = NULL;
+    g_autoptr(GSocketConnection) socket_conn = NULL;
+    g_autofree char *guid = g_dbus_generate_guid();
+    DBusDisplayListener *listener;
+    int fd;
+
+    if (g_hash_table_contains(ddc->listeners, sender)) {
+        g_dbus_method_invocation_return_error(
+            invocation,
+            DBUS_DISPLAY_ERROR,
+            DBUS_DISPLAY_ERROR_INVALID,
+            "`%s` is already registered!",
+            sender);
+        return DBUS_METHOD_INVOCATION_HANDLED;
+    }
+
+    fd = g_unix_fd_list_get(fd_list, g_variant_get_handle(arg_listener), &err);
+    if (err) {
+        g_dbus_method_invocation_return_error(
+            invocation,
+            DBUS_DISPLAY_ERROR,
+            DBUS_DISPLAY_ERROR_FAILED,
+            "Couldn't get peer fd: %s", err->message);
+        return DBUS_METHOD_INVOCATION_HANDLED;
+    }
+
+    socket = g_socket_new_from_fd(fd, &err);
+    if (err) {
+        g_dbus_method_invocation_return_error(
+            invocation,
+            DBUS_DISPLAY_ERROR,
+            DBUS_DISPLAY_ERROR_FAILED,
+            "Couldn't make a socket: %s", err->message);
+        close(fd);
+        return DBUS_METHOD_INVOCATION_HANDLED;
+    }
+    socket_conn = g_socket_connection_factory_create_connection(socket);
+
+    qemu_dbus_display1_console_complete_register_listener(
+        ddc->iface, invocation, NULL);
+
+    listener_conn = g_dbus_connection_new_sync(
+        G_IO_STREAM(socket_conn),
+        guid,
+        G_DBUS_CONNECTION_FLAGS_AUTHENTICATION_SERVER,
+        NULL, NULL, &err);
+    if (err) {
+        error_report("Failed to setup peer connection: %s", err->message);
+        return DBUS_METHOD_INVOCATION_HANDLED;
+    }
+
+    listener = dbus_display_listener_new(sender, listener_conn, ddc);
+    if (!listener) {
+        return DBUS_METHOD_INVOCATION_HANDLED;
+    }
+
+    g_hash_table_insert(ddc->listeners,
+                        (gpointer)dbus_display_listener_get_bus_name(listener),
+                        listener);
+    g_object_connect(listener_conn,
+                     "swapped-signal::closed", listener_vanished_cb, listener,
+                     NULL);
+
+    trace_dbus_registered_listener(sender);
+    return DBUS_METHOD_INVOCATION_HANDLED;
+}
+
+static gboolean
+dbus_kbd_press(DBusDisplayConsole *ddc,
+               GDBusMethodInvocation *invocation,
+               guint arg_keycode)
+{
+    QKeyCode qcode = qemu_input_key_number_to_qcode(arg_keycode);
+
+    trace_dbus_kbd_press(arg_keycode);
+
+    qkbd_state_key_event(ddc->kbd, qcode, true);
+
+    qemu_dbus_display1_keyboard_complete_press(ddc->iface_kbd, invocation);
+
+    return DBUS_METHOD_INVOCATION_HANDLED;
+}
+
+static gboolean
+dbus_kbd_release(DBusDisplayConsole *ddc,
+                 GDBusMethodInvocation *invocation,
+                 guint arg_keycode)
+{
+    QKeyCode qcode = qemu_input_key_number_to_qcode(arg_keycode);
+
+    trace_dbus_kbd_release(arg_keycode);
+
+    qkbd_state_key_event(ddc->kbd, qcode, false);
+
+    qemu_dbus_display1_keyboard_complete_release(ddc->iface_kbd, invocation);
+
+    return DBUS_METHOD_INVOCATION_HANDLED;
+}
+
+static void
+dbus_kbd_qemu_leds_updated(void *data, int ledstate)
+{
+    DBusDisplayConsole *ddc = DBUS_DISPLAY_CONSOLE(data);
+
+    qemu_dbus_display1_keyboard_set_modifiers(ddc->iface_kbd, ledstate);
+}
+
+static gboolean
+dbus_mouse_rel_motion(DBusDisplayConsole *ddc,
+                      GDBusMethodInvocation *invocation,
+                      int dx, int dy)
+{
+    trace_dbus_mouse_rel_motion(dx, dy);
+
+    if (qemu_input_is_absolute()) {
+        g_dbus_method_invocation_return_error(
+            invocation, DBUS_DISPLAY_ERROR,
+            DBUS_DISPLAY_ERROR_INVALID,
+            "Mouse is not relative");
+        return DBUS_METHOD_INVOCATION_HANDLED;
+    }
+
+    qemu_input_queue_rel(ddc->con, INPUT_AXIS_X, dx);
+    qemu_input_queue_rel(ddc->con, INPUT_AXIS_Y, dy);
+    qemu_input_event_sync();
+
+    qemu_dbus_display1_mouse_complete_rel_motion(ddc->iface_mouse,
+                                                    invocation);
+
+    return DBUS_METHOD_INVOCATION_HANDLED;
+}
+
+static gboolean
+dbus_mouse_set_pos(DBusDisplayConsole *ddc,
+                   GDBusMethodInvocation *invocation,
+                   guint x, guint y)
+{
+    int width, height;
+
+    trace_dbus_mouse_set_pos(x, y);
+
+    if (!qemu_input_is_absolute()) {
+        g_dbus_method_invocation_return_error(
+            invocation, DBUS_DISPLAY_ERROR,
+            DBUS_DISPLAY_ERROR_INVALID,
+            "Mouse is not absolute");
+        return DBUS_METHOD_INVOCATION_HANDLED;
+    }
+
+    width = qemu_console_get_width(ddc->con, 0);
+    height = qemu_console_get_height(ddc->con, 0);
+    if (x >= width || y >= height) {
+        g_dbus_method_invocation_return_error(
+            invocation, DBUS_DISPLAY_ERROR,
+            DBUS_DISPLAY_ERROR_INVALID,
+            "Invalid mouse position");
+        return DBUS_METHOD_INVOCATION_HANDLED;
+    }
+    qemu_input_queue_abs(ddc->con, INPUT_AXIS_X, x, 0, width);
+    qemu_input_queue_abs(ddc->con, INPUT_AXIS_Y, y, 0, height);
+    qemu_input_event_sync();
+
+    qemu_dbus_display1_mouse_complete_set_abs_position(ddc->iface_mouse,
+                                                          invocation);
+
+    return DBUS_METHOD_INVOCATION_HANDLED;
+}
+
+static gboolean
+dbus_mouse_press(DBusDisplayConsole *ddc,
+                 GDBusMethodInvocation *invocation,
+                 guint button)
+{
+    trace_dbus_mouse_press(button);
+
+    qemu_input_queue_btn(ddc->con, button, true);
+    qemu_input_event_sync();
+
+    qemu_dbus_display1_mouse_complete_press(ddc->iface_mouse, invocation);
+
+    return DBUS_METHOD_INVOCATION_HANDLED;
+}
+
+static gboolean
+dbus_mouse_release(DBusDisplayConsole *ddc,
+                   GDBusMethodInvocation *invocation,
+                   guint button)
+{
+    trace_dbus_mouse_release(button);
+
+    qemu_input_queue_btn(ddc->con, button, false);
+    qemu_input_event_sync();
+
+    qemu_dbus_display1_mouse_complete_release(ddc->iface_mouse, invocation);
+
+    return DBUS_METHOD_INVOCATION_HANDLED;
+}
+
+static void
+dbus_mouse_mode_change(Notifier *notify, void *data)
+{
+    DBusDisplayConsole *ddc =
+        container_of(notify, DBusDisplayConsole, mouse_mode_notifier);
+
+    g_object_set(ddc->iface_mouse,
+                 "is-absolute", qemu_input_is_absolute(),
+                 NULL);
+}
+
+int dbus_display_console_get_index(DBusDisplayConsole *ddc)
+{
+    return qemu_console_get_index(ddc->con);
+}
+
+DBusDisplayConsole *
+dbus_display_console_new(DBusDisplay *display, QemuConsole *con)
+{
+    g_autofree char *path = NULL;
+    g_autofree char *label = NULL;
+    char device_addr[256] = "";
+    DBusDisplayConsole *ddc;
+    int idx;
+
+    assert(display);
+    assert(con);
+
+    label = qemu_console_get_label(con);
+    idx = qemu_console_get_index(con);
+    path = g_strdup_printf(DBUS_DISPLAY1_ROOT "/Console_%d", idx);
+    ddc = g_object_new(DBUS_DISPLAY_TYPE_CONSOLE,
+                        "g-object-path", path,
+                        NULL);
+    ddc->display = display;
+    ddc->con = con;
+    /* handle errors, and skip non graphics? */
+    qemu_console_fill_device_address(
+        con, device_addr, sizeof(device_addr), NULL);
+
+    ddc->iface = qemu_dbus_display1_console_skeleton_new();
+    g_object_set(ddc->iface,
+        "label", label,
+        "type", qemu_console_is_graphic(con) ? "Graphic" : "Text",
+        "head", qemu_console_get_head(con),
+        "width", qemu_console_get_width(con, 0),
+        "height", qemu_console_get_height(con, 0),
+        "device-address", device_addr,
+        NULL);
+    g_object_connect(ddc->iface,
+        "swapped-signal::handle-register-listener",
+        dbus_console_register_listener, ddc,
+        "swapped-signal::handle-set-uiinfo",
+        dbus_console_set_ui_info, ddc,
+        NULL);
+    g_dbus_object_skeleton_add_interface(G_DBUS_OBJECT_SKELETON(ddc),
+        G_DBUS_INTERFACE_SKELETON(ddc->iface));
+
+    ddc->kbd = qkbd_state_init(con);
+    ddc->iface_kbd = qemu_dbus_display1_keyboard_skeleton_new();
+    qemu_add_led_event_handler(dbus_kbd_qemu_leds_updated, ddc);
+    g_object_connect(ddc->iface_kbd,
+        "swapped-signal::handle-press", dbus_kbd_press, ddc,
+        "swapped-signal::handle-release", dbus_kbd_release, ddc,
+        NULL);
+    g_dbus_object_skeleton_add_interface(G_DBUS_OBJECT_SKELETON(ddc),
+        G_DBUS_INTERFACE_SKELETON(ddc->iface_kbd));
+
+    ddc->iface_mouse = qemu_dbus_display1_mouse_skeleton_new();
+    g_object_connect(ddc->iface_mouse,
+        "swapped-signal::handle-set-abs-position", dbus_mouse_set_pos, ddc,
+        "swapped-signal::handle-rel-motion", dbus_mouse_rel_motion, ddc,
+        "swapped-signal::handle-press", dbus_mouse_press, ddc,
+        "swapped-signal::handle-release", dbus_mouse_release, ddc,
+        NULL);
+    g_dbus_object_skeleton_add_interface(G_DBUS_OBJECT_SKELETON(ddc),
+        G_DBUS_INTERFACE_SKELETON(ddc->iface_mouse));
+
+    register_displaychangelistener(&ddc->dcl);
+    ddc->mouse_mode_notifier.notify = dbus_mouse_mode_change;
+    qemu_add_mouse_mode_change_notifier(&ddc->mouse_mode_notifier);
+
+    return ddc;
+}