Implement ext-transient-seat-v1

protocols/meson.build

@@ -22,6 +22,7 @@ client_protocols = [
 	'linux-dmabuf-unstable-v1.xml',
 	'wlr-data-control-unstable-v1.xml',
 	'wlr-output-power-management-unstable-v1.xml',
+	'transient-seat-v1.xml',
 ]
 
 client_protos_src = []

protocols/transient-seat-v1.xml

@@ -0,0 +1,107 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<protocol name="transient_seat_v1">
+  <copyright>
+    Copyright © 2020 - 2023 Andri Yngvason
+
+    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 (including the next
+    paragraph) 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.
+  </copyright>
+
+  <description summary="protocol for creating temporary seats">
+    The transient seat protocol can be used by privileved clients to create
+    independent seats that will be removed from the compositor when the client
+    destroys its seat.
+
+    This protocol is intended for use with virtual input protocols such as
+    "virtual_keyboard_unstable_v1" or "wlr_virtual_pointer_unstable_v1", both
+    of which allow the user to select a seat.
+
+    The "wl_seat" global created by this protocol does not generate input events
+    on its own, or have any capabilities except those assigned to it by other
+    protocol extensions, such as the ones mentioned above.
+
+    For example, a remote desktop server can create a seat with virtual inputs
+    for each remote user by following these steps for each new connection:
+     * Create a transient seat
+     * Wait for the transient seat to be created
+     * Locate a "wl_seat" global with a matching name
+     * Create virtual inputs using the resulting "wl_seat" global
+  </description>
+
+  <interface name="ext_transient_seat_manager_v1" version="1">
+    <description summary="transient seat manager">
+      The transient seat manager creates short-lived seats.
+    </description>
+
+    <request name="create">
+      <description summary="create a transient seat">
+        Create a new seat that is removed when the client side object is
+        destroyed.
+      </description>
+      <arg name="seat" type="new_id" interface="ext_transient_seat_v1"/>
+    </request>
+
+    <request name="destroy" type="destructor">
+      <description summary="destroy the manager">
+        Destroy the manager.
+
+        All objects created by the manager will remain valid until they are
+        destroyed themselves.
+      </description>
+    </request>
+  </interface>
+
+  <interface name="ext_transient_seat_v1" version="1">
+    <description summary="transient seat handle">
+      The life time of the transient seat handle is equal to that of the seat
+      itself.
+    </description>
+
+    <event name="ready">
+      <description summary="transient seat is ready">
+        This event advertises the global name for the wl_seat to be used with
+        wl_registry_bind.
+
+        It is sent exactly once, immediately after the transient seat is created
+        and the new "wl_seat" global is advertised, if and only if the creation
+        of the transient seat was allowed.
+      </description>
+      <arg name="global_name" type="uint"/>
+    </event>
+
+    <event name="denied">
+      <description summary="transient seat creation denied">
+        The event informs the client that the compositor denied its request to
+        create a transient seat.
+
+        It is sent exactly once, immediately after the transient seat object is
+        created, if and only if the creation of the transient seat was denied.
+
+        After receiving this event, the client should destroy the object.
+      </description>
+    </event>
+
+    <request name="destroy" type="destructor">
+      <description summary="destroy transient seat">
+        When the transient seat object is destroyed by the client, the
+        associated seat created by the compositor is also destroyed.
+      </description>
+    </request>
+  </interface>
+</protocol>

src/main.c

@@ -40,6 +40,7 @@
 #include "xdg-output-unstable-v1.h"
 #include "wlr-output-power-management-unstable-v1.h"
 #include "linux-dmabuf-unstable-v1.h"
+#include "transient-seat-v1.h"
 #include "screencopy.h"
 #include "data-control.h"
 #include "strlcpy.h"
@@ -83,9 +84,10 @@ struct wayvnc {
 	struct zwp_virtual_keyboard_manager_v1* keyboard_manager;
 	struct zwlr_virtual_pointer_manager_v1* pointer_manager;
 	struct zwlr_data_control_manager_v1* data_control_manager;
+	struct ext_transient_seat_manager_v1* transient_seat_manager;
 
 	struct output* selected_output;
-	const struct seat* selected_seat;
+	struct seat* selected_seat;
 
 	struct screencopy screencopy;
 
@@ -102,6 +104,7 @@ struct wayvnc {
 	uint32_t n_frames_captured;
 
 	bool disable_input;
+	bool use_transient_seat;
 
 	int nr_clients;
 	struct aml_ticker* performance_ticker;
@@ -116,6 +119,9 @@ struct wayvnc_client {
 	struct wayvnc* server;
 	struct nvnc_client* nvnc_client;
 
+	struct wl_seat* seat;
+	struct ext_transient_seat_v1* transient_seat;
+
 	unsigned id;
 	struct pointer pointer;
 	struct keyboard keyboard;
@@ -128,6 +134,7 @@ static void on_nvnc_client_new(struct nvnc_client* client);
 void switch_to_output(struct wayvnc*, struct output*);
 void switch_to_next_output(struct wayvnc*);
 void switch_to_prev_output(struct wayvnc*);
+static void client_init_seat(struct wayvnc_client* self);
 static void client_init_pointer(struct wayvnc_client* self);
 static void client_init_keyboard(struct wayvnc_client* self);
 static void client_init_data_control(struct wayvnc_client* self);
@@ -155,7 +162,7 @@ static bool registry_add_input(void* data, struct wl_registry* registry,
 
 		struct seat* seat = seat_new(wl_seat, id);
 		if (!seat) {
-			wl_seat_destroy(wl_seat);
+			wl_seat_release(wl_seat);
 			return true;
 		}
 
@@ -183,6 +190,12 @@ static bool registry_add_input(void* data, struct wl_registry* registry,
 		return true;
 	}
 
+	if (strcmp(interface, ext_transient_seat_manager_v1_interface.name) == 0) {
+		self->transient_seat_manager = wl_registry_bind(registry, id,
+				&ext_transient_seat_manager_v1_interface, 1);
+		return true;
+	}
+
 	return false;
 }
 
@@ -416,6 +429,11 @@ static int init_wayland(struct wayvnc* self)
 		goto failure;
 	}
 
+	if (!self->transient_seat_manager && self->use_transient_seat) {
+		nvnc_log(NVNC_LOG_ERROR, "Transient seat protocol not supported by compositor.");
+		goto failure;
+	}
+
 	if (!self->screencopy.manager) {
 		nvnc_log(NVNC_LOG_ERROR, "Screencopy protocol not supported by compositor. Exiting. Refer to FAQ section in man page.");
 		goto failure;
@@ -1000,6 +1018,7 @@ static struct wayvnc_client* client_create(struct wayvnc* wayvnc,
 	self->nvnc_client = nvnc_client;
 
 	self->id = next_client_id++;
+	client_init_seat(self);
 	client_init_keyboard(self);
 	client_init_pointer(self);
 	client_init_data_control(self);
@@ -1023,6 +1042,10 @@ static void client_destroy(void* obj)
 	if (self->data_control.manager)
 		data_control_destroy(&self->data_control);
 
+	if (self->server->use_transient_seat) {
+		ext_transient_seat_v1_destroy(self->transient_seat);
+	}
+
 	free(self);
 }
 
@@ -1107,16 +1130,73 @@ static void client_init_pointer(struct wayvnc_client* self)
 
 	self->pointer.pointer = pointer_manager_version >= 2
 		? zwlr_virtual_pointer_manager_v1_create_virtual_pointer_with_output(
-			wayvnc->pointer_manager, wayvnc->selected_seat->wl_seat,
+			wayvnc->pointer_manager, self->seat,
 			wayvnc->selected_output->wl_output)
 		: zwlr_virtual_pointer_manager_v1_create_virtual_pointer(
-			wayvnc->pointer_manager, wayvnc->selected_seat->wl_seat);
+			wayvnc->pointer_manager, self->seat);
 
 	if (pointer_init(&self->pointer) < 0) {
 		nvnc_log(NVNC_LOG_ERROR, "Failed to initialise pointer");
 	}
 }
 
+static void handle_transient_seat_ready(void* data,
+		struct ext_transient_seat_v1* transient_seat,
+		uint32_t global_name)
+{
+	(void)transient_seat;
+
+	struct wayvnc_client* client = data;
+	struct wayvnc* wayvnc = client->server;
+
+	struct seat* seat = seat_find_by_id(&wayvnc->seats, global_name);
+	assert(seat);
+
+	client->seat = seat->wl_seat;
+}
+
+static void handle_transient_seat_denied(void* data,
+		struct ext_transient_seat_v1* transient_seat)
+{
+	(void)transient_seat;
+
+	struct wayvnc_client* client = data;
+	struct wayvnc* wayvnc = client->server;
+
+	// TODO: Should this perhaps be fatal?
+	nvnc_log(NVNC_LOG_WARNING, "Transient seat denied");
+
+	client->seat = wayvnc->selected_seat->wl_seat;
+}
+
+static void client_init_seat(struct wayvnc_client* self)
+{
+	struct wayvnc* wayvnc = self->server;
+
+	if (wayvnc->disable_input)
+		return;
+
+	if (wayvnc->use_transient_seat) {
+		self->transient_seat = ext_transient_seat_manager_v1_create(
+				wayvnc->transient_seat_manager);
+
+		static const struct ext_transient_seat_v1_listener listener = {
+			.ready = handle_transient_seat_ready,
+			.denied = handle_transient_seat_denied,
+		};
+		ext_transient_seat_v1_add_listener(self->transient_seat,
+				&listener, self);
+
+		// TODO: Make this asynchronous
+		wl_display_roundtrip(wayvnc->display);
+		wl_display_dispatch(wayvnc->display);
+
+		assert(self->seat);
+	} else {
+		self->seat = wayvnc->selected_seat->wl_seat;
+	}
+}
+
 static void client_init_keyboard(struct wayvnc_client* self)
 {
 	struct wayvnc* wayvnc = self->server;
@@ -1126,8 +1206,7 @@ static void client_init_keyboard(struct wayvnc_client* self)
 
 	self->keyboard.virtual_keyboard =
 		zwp_virtual_keyboard_manager_v1_create_virtual_keyboard(
-			wayvnc->keyboard_manager,
+			wayvnc->keyboard_manager, self->seat);
-			wayvnc->selected_seat->wl_seat);
 
 	struct xkb_rule_names rule_names = {
 		.rules = wayvnc->cfg.xkb_rules,
@@ -1163,7 +1242,7 @@ static void client_init_data_control(struct wayvnc_client* self)
 
 	self->data_control.manager = wayvnc->data_control_manager;
 	data_control_init(&self->data_control, wayvnc->display, wayvnc->nvnc,
-			wayvnc->selected_seat->wl_seat);
+			self->seat);
 }
 
 void log_selected_output(struct wayvnc* self)
@@ -1266,6 +1345,7 @@ int main(int argc, char* argv[])
 	bool show_performance = false;
 	int max_rate = 30;
 	bool disable_input = false;
+	bool use_transient_seat = false;
 
 	int drm_fd MAYBE_UNUSED = -1;
 
@@ -1290,6 +1370,8 @@ int main(int argc, char* argv[])
 		  "Select seat by name." },
 		{ 'S', "socket", "<path>",
 		  "Control socket path." },
+		{ 't', "transient-seat", NULL,
+		  "Use transient seat." },
 		{ 'r', "render-cursor", NULL,
 		  "Enable overlay cursor rendering." },
 		{ 'f', "max-fps", "<fps>",
@@ -1342,6 +1424,7 @@ int main(int argc, char* argv[])
 	log_level = log_level_from_string(
 			option_parser_get_value(&option_parser, "log-level"));
 	max_rate = atoi(option_parser_get_value(&option_parser, "max-fps"));
+	use_transient_seat = option_parser_get_value(&option_parser, "transient-seat");
 
 	keyboard_options = option_parser_get_value(&option_parser, "keyboard");
 	if (keyboard_options)
@@ -1361,6 +1444,16 @@ int main(int argc, char* argv[])
 		return 1;
 	}
 
+	if (use_transient_seat && disable_input) {
+		nvnc_log(NVNC_LOG_ERROR, "transient-seat and disable-input are conflicting options");
+		return 1;
+	}
+
+	if (seat_name && use_transient_seat) {
+		nvnc_log(NVNC_LOG_ERROR, "transient seat and seat are conflicting options");
+		return 1;
+	}
+
 	errno = 0;
 	int cfg_rc = cfg_load(&self.cfg, cfg_file);
 	if (cfg_rc != 0 && (cfg_file || errno != ENOENT)) {
@@ -1386,6 +1479,7 @@ int main(int argc, char* argv[])
 	if (!port) port = DEFAULT_PORT;
 
 	self.disable_input = disable_input;
+	self.use_transient_seat = use_transient_seat;
 
 	if (init_wayland(&self) < 0) {
 		nvnc_log(NVNC_LOG_ERROR, "Failed to initialise wayland");
@@ -1415,7 +1509,7 @@ int main(int argc, char* argv[])
 			nvnc_log(NVNC_LOG_ERROR, "No such seat");
 			goto failure;
 		}
-	} else if (!self.disable_input) {
+	} else if (!self.disable_input && !self.use_transient_seat) {
 		seat = seat_first(&self.seats);
 		if (!seat) {
 			nvnc_log(NVNC_LOG_ERROR, "No seat found");