session: Add libseat backend

.builds/alpine.yml

@@ -16,7 +16,7 @@ sources:
 tasks:
   - setup: |
       cd wlroots
-      meson build -Dauto_features=enabled -Dlogind=disabled -Dxcb-errors=disabled
+      meson build -Dauto_features=enabled -Dlogind=disabled -Dlibseat=disabled -Dxcb-errors=disabled
   - build: |
       cd wlroots
       ninja -C build

.builds/archlinux.yml

@@ -12,6 +12,7 @@ packages:
   - xcb-util-errors
   - xcb-util-image
   - xcb-util-wm
+  - seatd
 sources:
   - https://github.com/swaywm/wlroots
 tasks:

.builds/freebsd.yml

@@ -18,6 +18,7 @@ packages:
 - x11/pixman
 - x11/xcb-util-errors
 - x11/xcb-util-wm
+- sysutils/seatd
 sources:
 - https://github.com/swaywm/wlroots
 tasks:

backend/session/direct.c

@@ -18,6 +18,7 @@
 #include <wlr/backend/session/interface.h>
 #include <wlr/util/log.h>
 #include "backend/session/direct-ipc.h"
+#include "backend/session/session.h"
 #include "util/signal.h"
 
 enum { DRM_MAJOR = 226 };
@@ -246,6 +247,7 @@ static struct wlr_session *direct_session_create(struct wl_display *disp) {
 		return NULL;
 	}
 
+	session_init(&session->base);
 	session->sock = direct_ipc_init(&session->child);
 	if (session->sock == -1) {
 		goto error_session;
@@ -267,6 +269,7 @@ static struct wlr_session *direct_session_create(struct wl_display *disp) {
 
 	snprintf(session->base.seat, sizeof(session->base.seat), "%s", seat);
 	session->base.impl = &session_direct;
+	session->base.active = true;
 
 	wlr_log(WLR_INFO, "Successfully loaded direct session");
 	return &session->base;

backend/session/libseat.c

@@ -0,0 +1,190 @@
+#define _POSIX_C_SOURCE 200809L
+#include <assert.h>
+#include <errno.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <wayland-server-core.h>
+#include <wlr/backend/session/interface.h>
+#include <wlr/config.h>
+#include <wlr/util/log.h>
+#include "backend/session/session.h"
+#include "util/signal.h"
+
+#include <libseat.h>
+
+const struct session_impl session_libseat;
+
+struct libseat_device {
+	struct wl_list link;
+	int fd;
+	int device_id;
+};
+
+struct libseat_session {
+	struct wlr_session base;
+
+	struct libseat *seat;
+	struct wl_event_source *event;
+	struct wl_list devices;
+};
+
+static void handle_enable_seat(struct libseat *seat, void *data) {
+	struct libseat_session *session = data;
+	session->base.active = true;
+	wlr_signal_emit_safe(&session->base.session_signal, session);
+}
+
+static void handle_disable_seat(struct libseat *seat, void *data) {
+	struct libseat_session *session = data;
+	session->base.active = false;
+	wlr_signal_emit_safe(&session->base.session_signal, session);
+	libseat_disable_seat(session->seat);
+}
+
+static int libseat_event(int fd, uint32_t mask, void *data) {
+	struct libseat *seat = data;
+	libseat_dispatch(seat, 0);
+	return 1;
+}
+
+static struct libseat_seat_listener seat_listener = {
+	.enable_seat = handle_enable_seat,
+	.disable_seat = handle_disable_seat,
+};
+
+static struct libseat_session *libseat_session_from_session(
+		struct wlr_session *base) {
+	assert(base->impl == &session_libseat);
+	return (struct libseat_session *)base;
+}
+
+static struct wlr_session *libseat_session_create(struct wl_display *disp) {
+	struct libseat_session *session = calloc(1, sizeof(*session));
+	if (!session) {
+		wlr_log_errno(WLR_ERROR, "Allocation failed");
+		return NULL;
+	}
+
+	session_init(&session->base);
+	wl_list_init(&session->devices);
+
+	session->seat = libseat_open_seat(&seat_listener, session);
+	if (session->seat == NULL) {
+		wlr_log_errno(WLR_ERROR, "Unable to create seat");
+		goto error;
+	}
+
+	const char *seat_name = libseat_seat_name(session->seat);
+	if (seat_name == NULL) {
+		wlr_log_errno(WLR_ERROR, "Unable to get seat info");
+		goto error;
+	}
+	snprintf(session->base.seat, sizeof(session->base.seat), "%s", seat_name);
+
+	struct wl_event_loop *event_loop = wl_display_get_event_loop(disp);
+	session->event = wl_event_loop_add_fd(event_loop, libseat_get_fd(session->seat),
+		WL_EVENT_READABLE, libseat_event, session->seat);
+	if (session->event == NULL) {
+		wlr_log(WLR_ERROR, "Failed to create libseat event source");
+		goto error;
+	}
+
+	// We may have received enable_seat immediately after the open_seat result,
+	// so, dispatch once without timeout to speed up activation.
+	if (libseat_dispatch(session->seat, 0) == -1) {
+		wlr_log_errno(WLR_ERROR, "libseat dispatch failed");
+		goto error;
+	}
+
+	wlr_log(WLR_INFO, "Successfully loaded libseat session");
+	session->base.impl = &session_libseat;
+	return &session->base;
+
+error:
+	if (session->seat != NULL) {
+		libseat_close_seat(session->seat);
+	}
+	if (session->event != NULL) {
+		wl_event_source_remove(session->event);
+	}
+	free(session);
+	return NULL;
+}
+
+static void libseat_session_destroy(struct wlr_session *base) {
+	struct libseat_session *session = libseat_session_from_session(base);
+
+	libseat_close_seat(session->seat);
+	wl_event_source_remove(session->event);
+	free(session);
+}
+
+static struct libseat_device *find_device_by_fd(struct libseat_session *session, int fd) {
+	struct libseat_device *dev;
+	wl_list_for_each(dev, &session->devices, link) {
+		if (dev->fd == fd) {
+			return dev;
+		}
+	}
+	return NULL;
+}
+
+static int libseat_session_open_device(struct wlr_session *base, const char *path) {
+	struct libseat_session *session = libseat_session_from_session(base);
+
+	int fd;
+	int device_id = libseat_open_device(session->seat, path, &fd);
+	if (device_id == -1) {
+		wlr_log_errno(WLR_ERROR, "Failed to open device '%s'", path);
+		return -1;
+	}
+
+	struct libseat_device *dev = calloc(1, sizeof(struct libseat_device));
+	if (dev == NULL) {
+		wlr_log_errno(WLR_ERROR, "Allocation failed");
+		libseat_close_device(session->seat, device_id);
+		return -1;
+	}
+
+	dev->fd = fd;
+	dev->device_id = device_id;
+	wl_list_insert(&session->devices, &dev->link);
+
+	return fd;
+}
+
+static void libseat_session_close_device(struct wlr_session *base, int fd) {
+	struct libseat_session *session = libseat_session_from_session(base);
+
+	struct libseat_device *dev = find_device_by_fd(session, fd);
+	if (dev == NULL) {
+		wlr_log(WLR_ERROR, "No device with fd %d found", fd);
+		close(fd);
+		return;
+	}
+
+	if (libseat_close_device(session->seat, dev->device_id) == -1) {
+		wlr_log_errno(WLR_ERROR, "Failed to close device %d", dev->device_id);
+	}
+
+	wl_list_remove(&dev->link);
+	free(dev);
+	close(fd);
+}
+
+static bool libseat_change_vt(struct wlr_session *base, unsigned vt) {
+	struct libseat_session *session = libseat_session_from_session(base);
+	return libseat_switch_session(session->seat, vt);
+}
+
+const struct session_impl session_libseat = {
+	.create = libseat_session_create,
+	.destroy = libseat_session_destroy,
+	.open = libseat_session_open_device,
+	.close = libseat_session_close_device,
+	.change_vt = libseat_change_vt,
+};

backend/session/logind.c

@@ -13,6 +13,7 @@
 #include <wlr/backend/session/interface.h>
 #include <wlr/config.h>
 #include <wlr/util/log.h>
+#include "backend/session/session.h"
 #include "util/signal.h"
 
 #if WLR_HAS_SYSTEMD
@@ -778,6 +779,8 @@ static struct wlr_session *logind_session_create(struct wl_display *disp) {
 		return NULL;
 	}
 
+	session_init(&session->base);
+
 	if (!get_display_session(&session->id)) {
 		goto error;
 	}
@@ -855,6 +858,8 @@ static struct wlr_session *logind_session_create(struct wl_display *disp) {
 	wlr_log(WLR_INFO, "Successfully loaded logind session");
 
 	session->base.impl = &session_logind;
+	session->base.active = true;
+
 	return &session->base;
 
 error_bus:

backend/session/meson.build

@@ -62,3 +62,12 @@ if logind_found
 	wlr_files += files('logind.c')
 	wlr_deps += logind
 endif
+
+# libseat
+
+libseat = dependency('libseat', required: get_option('libseat'))
+if libseat.found()
+	wlr_files += files('libseat.c')
+	wlr_deps += libseat
+	conf_data.set10('WLR_HAS_LIBSEAT', true)
+endif

backend/session/noop.c

@@ -6,6 +6,7 @@
 #include <wayland-server-core.h>
 #include <wlr/backend/session/interface.h>
 #include <wlr/util/log.h>
+#include "backend/session/session.h"
 #include "util/signal.h"
 
 const struct session_impl session_noop;
@@ -33,7 +34,9 @@ static struct wlr_session *noop_session_create(struct wl_display *disp) {
 		return NULL;
 	}
 
+	session_init(session);
 	session->impl = &session_noop;
+	session->active = true;
 
 	wlr_log(WLR_INFO, "Successfully initialized noop session");
 	return session;

backend/session/session.c

@@ -13,13 +13,18 @@
 #include <wlr/util/log.h>
 #include <xf86drm.h>
 #include <xf86drmMode.h>
+#include "backend/session/session.h"
 #include "util/signal.h"
 
+extern const struct session_impl session_libseat;
 extern const struct session_impl session_logind;
 extern const struct session_impl session_direct;
 extern const struct session_impl session_noop;
 
 static const struct session_impl *impls[] = {
+#if WLR_HAS_LIBSEAT
+	&session_libseat,
+#endif
 #if WLR_HAS_SYSTEMD || WLR_HAS_ELOGIND
 	&session_logind,
 #endif
@@ -65,12 +70,24 @@ static void handle_display_destroy(struct wl_listener *listener, void *data) {
 	wlr_session_destroy(session);
 }
 
+void session_init(struct wlr_session *session) {
+	wl_signal_init(&session->session_signal);
+	wl_signal_init(&session->events.destroy);
+	wl_list_init(&session->devices);
+}
+
 struct wlr_session *wlr_session_create(struct wl_display *disp) {
 	struct wlr_session *session = NULL;
 
 	const char *env_wlr_session = getenv("WLR_SESSION");
 	if (env_wlr_session) {
-		if (strcmp(env_wlr_session, "logind") == 0 ||
+		if (strcmp(env_wlr_session, "libseat") == 0) {
+#if WLR_HAS_LIBSEAT
+			session = session_libseat.create(disp);
+#else
+			wlr_log(WLR_ERROR, "wlroots is not compiled with libseat support");
+#endif
+		} else if (strcmp(env_wlr_session, "logind") == 0 ||
 				strcmp(env_wlr_session, "systemd") == 0) {
 #if WLR_HAS_SYSTEMD || WLR_HAS_ELOGIND
 			session = session_logind.create(disp);
@@ -97,11 +114,6 @@ struct wlr_session *wlr_session_create(struct wl_display *disp) {
 		return NULL;
 	}
 
-	session->active = true;
-	wl_signal_init(&session->session_signal);
-	wl_signal_init(&session->events.destroy);
-	wl_list_init(&session->devices);
-
 	session->udev = udev_new();
 	if (!session->udev) {
 		wlr_log_errno(WLR_ERROR, "Failed to create udev context");

include/backend/session/session.h

@@ -0,0 +1,8 @@
+#ifndef BACKEND_SESSION_SESSION_H
+#define BACKEND_SESSION_SESSION_H
+
+struct wlr_session;
+
+void session_init(struct wlr_session *session);
+
+#endif

include/wlr/config.h.in

@@ -8,6 +8,8 @@
 #mesondefine WLR_HAS_SYSTEMD
 #mesondefine WLR_HAS_ELOGIND
 
+#mesondefine WLR_HAS_LIBSEAT
+
 #mesondefine WLR_HAS_X11_BACKEND
 
 #mesondefine WLR_HAS_XWAYLAND

meson.build

@@ -82,6 +82,7 @@ endif
 conf_data = configuration_data()
 conf_data.set10('WLR_HAS_SYSTEMD', false)
 conf_data.set10('WLR_HAS_ELOGIND', false)
+conf_data.set10('WLR_HAS_LIBSEAT', false)
 conf_data.set10('WLR_HAS_X11_BACKEND', false)
 conf_data.set10('WLR_HAS_XWAYLAND', false)
 conf_data.set10('WLR_HAS_XCB_ERRORS', false)
@@ -176,6 +177,7 @@ meson.override_dependency('wlroots', wlroots)
 summary({
 	'systemd': conf_data.get('WLR_HAS_SYSTEMD', 0),
 	'elogind': conf_data.get('WLR_HAS_ELOGIND', 0),
+	'libseat': conf_data.get('WLR_HAS_LIBSEAT', 0),
 	'xwayland': conf_data.get('WLR_HAS_XWAYLAND', 0),
 	'x11_backend': conf_data.get('WLR_HAS_X11_BACKEND', 0),
 	'xcb-icccm': conf_data.get('WLR_HAS_XCB_ICCCM', 0),

meson_options.txt

@@ -1,5 +1,6 @@
 option('logind', type: 'feature', value: 'auto', description: 'Enable support for rootless session via logind')
 option('logind-provider', type: 'combo', choices: ['auto', 'systemd', 'elogind'], value: 'auto', description: 'Provider of logind support library')
+option('libseat', type: 'feature', value: 'auto', description: 'Enable support for rootless session via libseat')
 option('xcb-errors', type: 'feature', value: 'auto', description: 'Use xcb-errors util library')
 option('xcb-icccm', type: 'feature', value: 'auto', description: 'Use xcb-icccm util library')
 option('xwayland', type: 'feature', value: 'auto', yield: true, description: 'Enable support for X11 applications')