1 files changed, 398 insertions, 0 deletions
diff --git a/backend/session/logind.c b/backend/session/logind.c
new file mode 100644
index 00000000..6744215a
--- /dev/null
+++ b/backend/session/logind.c
@@ -0,0 +1,398 @@
+#define _POSIX_C_SOURCE 200809L
+#include <stdio.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <systemd/sd-bus.h>
+#include <systemd/sd-login.h>
+#include <unistd.h>
+#include <sys/sysmacros.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <wayland-server.h>
+#include <wlr/session/interface.h>
+#include <wlr/util/log.h>
+
+enum { DRM_MAJOR = 226 };
+
+const struct session_impl session_logind;
+
+struct logind_session {
+	struct wlr_session base;
+
+	sd_bus *bus;
+	struct wl_event_source *event;
+
+	char *id;
+	char *path;
+};
+
+static int logind_take_device(struct wlr_session *base, const char *path) {
+	struct logind_session *session = wl_container_of(base, session, base);
+
+	int ret;
+	int fd = -1;
+	sd_bus_message *msg = NULL;
+	sd_bus_error error = SD_BUS_ERROR_NULL;
+
+	struct stat st;
+	if (stat(path, &st) < 0) {
+		wlr_log(L_ERROR, "Failed to stat '%s'", path);
+		return -1;
+	}
+
+	ret = sd_bus_call_method(session->bus, "org.freedesktop.login1",
+		session->path, "org.freedesktop.login1.Session", "TakeDevice",
+		&error, &msg, "uu", major(st.st_rdev), minor(st.st_rdev));
+	if (ret < 0) {
+		wlr_log(L_ERROR, "Failed to take device '%s': %s", path, error.message);
+		goto error;
+	}
+
+	int paused = 0;
+	ret = sd_bus_message_read(msg, "hb", &fd, &paused);
+	if (ret < 0) {
+		wlr_log(L_ERROR, "Failed to parse D-Bus response for '%s': %s",
+			path, strerror(-ret));
+		goto error;
+	}
+
+	// The original fd seems to be closed when the message is freed
+	// so we just clone it.
+	fd = fcntl(fd, F_DUPFD_CLOEXEC, 0);
+	if (fd == -1) {
+		wlr_log(L_ERROR, "Failed to clone file descriptor for '%s': %s",
+			path, strerror(errno));
+		goto error;
+	}
+
+	if (major(st.st_rdev) == DRM_MAJOR) {
+		session->base.drm_fd = fd;
+	}
+
+error:
+	sd_bus_error_free(&error);
+	sd_bus_message_unref(msg);
+	return fd;
+}
+
+static void logind_release_device(struct wlr_session *base, int fd) {
+	struct logind_session *session = wl_container_of(base, session, base);
+
+	int ret;
+	sd_bus_message *msg = NULL;
+	sd_bus_error error = SD_BUS_ERROR_NULL;
+
+	struct stat st;
+	if (fstat(fd, &st) < 0) {
+		wlr_log(L_ERROR, "Failed to stat device '%d'", fd);
+		return;
+	}
+
+	ret = sd_bus_call_method(session->bus, "org.freedesktop.login1",
+		session->path, "org.freedesktop.login1.Session", "ReleaseDevice",
+		&error, &msg, "uu", major(st.st_rdev), minor(st.st_rdev));
+	if (ret < 0) {
+		wlr_log(L_ERROR, "Failed to release device '%d'", fd);
+	}
+
+	if (major(st.st_rdev) == DRM_MAJOR) {
+		session->base.drm_fd = -1;
+	}
+
+	sd_bus_error_free(&error);
+	sd_bus_message_unref(msg);
+}
+
+static bool logind_change_vt(struct wlr_session *base, unsigned vt) {
+	struct logind_session *session = wl_container_of(base, session, base);
+
+	int ret;
+	sd_bus_message *msg = NULL;
+	sd_bus_error error = SD_BUS_ERROR_NULL;
+
+	ret = sd_bus_call_method(session->bus, "org.freedesktop.login1",
+		"/org/freedesktop/login1/seat/self", "org.freedesktop.login1.Seat", "SwitchTo",
+		&error, &msg, "u", (uint32_t)vt);
+	if (ret < 0) {
+		wlr_log(L_ERROR, "Failed to change to vt '%d'", vt);
+	}
+
+	sd_bus_error_free(&error);
+	sd_bus_message_unref(msg);
+	return ret >= 0;
+}
+
+static bool find_sesion_path(struct logind_session *session) {
+	int ret;
+	sd_bus_message *msg = NULL;
+	sd_bus_error error = SD_BUS_ERROR_NULL;
+
+	ret = sd_bus_call_method(session->bus, "org.freedesktop.login1",
+			"/org/freedesktop/login1", "org.freedesktop.login1.Manager",
+			"GetSession", &error, &msg, "s", session->id);
+	if (ret < 0) {
+		wlr_log(L_ERROR, "Failed to get session path: %s", strerror(-ret));
+		goto out;
+	}
+
+	const char *path;
+
+	ret = sd_bus_message_read(msg, "o", &path);
+	if (ret < 0) {
+		wlr_log(L_ERROR, "Could not parse session path: %s", strerror(-ret));
+		goto out;
+	}
+
+	session->path = strdup(path);
+
+out:
+	sd_bus_error_free(&error);
+	sd_bus_message_unref(msg);
+
+	return ret >= 0;
+}
+
+static bool session_activate(struct logind_session *session) {
+	int ret;
+	sd_bus_message *msg = NULL;
+	sd_bus_error error = SD_BUS_ERROR_NULL;
+
+	ret = sd_bus_call_method(session->bus, "org.freedesktop.login1",
+		session->path, "org.freedesktop.login1.Session", "Activate",
+		&error, &msg, "");
+	if (ret < 0) {
+		wlr_log(L_ERROR, "Failed to activate session");
+	}
+
+	sd_bus_error_free(&error);
+	sd_bus_message_unref(msg);
+	return ret >= 0;
+}
+
+static bool take_control(struct logind_session *session) {
+	int ret;
+	sd_bus_message *msg = NULL;
+	sd_bus_error error = SD_BUS_ERROR_NULL;
+
+	ret = sd_bus_call_method(session->bus, "org.freedesktop.login1",
+		session->path, "org.freedesktop.login1.Session", "TakeControl",
+		&error, &msg, "b", false);
+	if (ret < 0) {
+		wlr_log(L_ERROR, "Failed to take control of session");
+	}
+
+	sd_bus_error_free(&error);
+	sd_bus_message_unref(msg);
+	return ret >= 0;
+}
+
+static void release_control(struct logind_session *session) {
+	int ret;
+	sd_bus_message *msg = NULL;
+	sd_bus_error error = SD_BUS_ERROR_NULL;
+
+	ret = sd_bus_call_method(session->bus, "org.freedesktop.login1",
+		session->path, "org.freedesktop.login1.Session", "ReleaseControl",
+		&error, &msg, "");
+	if (ret < 0) {
+		wlr_log(L_ERROR, "Failed to release control of session");
+	}
+
+	sd_bus_error_free(&error);
+	sd_bus_message_unref(msg);
+}
+
+static void logind_session_finish(struct wlr_session *base) {
+	struct logind_session *session = wl_container_of(base, session, base);
+
+	release_control(session);
+
+	wl_event_source_remove(session->event);
+	sd_bus_unref(session->bus);
+	free(session->id);
+	free(session->path);
+	free(session);
+}
+
+static int session_removed(sd_bus_message *msg, void *userdata, sd_bus_error *ret_error) {
+	wlr_log(L_INFO, "SessionRemoved signal received");
+	return 0;
+}
+
+static int pause_device(sd_bus_message *msg, void *userdata, sd_bus_error *ret_error) {
+	struct logind_session *session = userdata;
+	int ret;
+
+	uint32_t major, minor;
+	const char *type;
+	ret = sd_bus_message_read(msg, "uus", &major, &minor, &type);
+	if (ret < 0) {
+		wlr_log(L_ERROR, "Failed to parse D-Bus response for PauseDevice: %s",
+			strerror(-ret));
+		goto error;
+	}
+
+	if (major == DRM_MAJOR) {
+		session->base.active = false;
+		wl_signal_emit(&session->base.session_signal, session);
+	}
+
+	if (strcmp(type, "pause") == 0) {
+		ret = sd_bus_call_method(session->bus, "org.freedesktop.login1",
+			session->path, "org.freedesktop.login1.Session", "PauseDeviceComplete",
+			ret_error, &msg, "uu", major, minor);
+		if (ret < 0) {
+			wlr_log(L_ERROR, "Failed to send PauseDeviceComplete signal: %s",
+				strerror(-ret));
+		}
+	}
+
+error:
+	return 0;
+}
+
+static int resume_device(sd_bus_message *msg, void *userdata, sd_bus_error *ret_error) {
+	struct logind_session *session = userdata;
+	int ret;
+
+	int fd;
+	uint32_t major, minor;
+	ret = sd_bus_message_read(msg, "uuh", &major, &minor, &fd);
+	if (ret < 0) {
+		wlr_log(L_ERROR, "Failed to parse D-Bus response for ResumeDevice: %s",
+			strerror(-ret));
+		goto error;
+	}
+
+	if (major == DRM_MAJOR) {
+		dup2(fd, session->base.drm_fd);
+		session->base.active = true;
+		wl_signal_emit(&session->base.session_signal, session);
+	}
+
+error:
+	return 0;
+}
+
+static bool add_signal_matches(struct logind_session *session) {
+	int ret;
+
+	char str[256];
+	const char *fmt = "type='signal',"
+		"sender='org.freedesktop.login1',"
+		"interface='org.freedesktop.login1.%s',"
+		"member='%s',"
+		"path='%s'";
+
+	snprintf(str, sizeof(str), fmt, "Manager", "SesssionRemoved", "/org/freedesktop/login1");
+	ret = sd_bus_add_match(session->bus, NULL, str, session_removed, session);
+	if (ret < 0) {
+		wlr_log(L_ERROR, "Failed to add D-Bus match: %s", strerror(-ret));
+		return false;
+	}
+
+	snprintf(str, sizeof(str), fmt, "Session", "PauseDevice", session->path);
+	ret = sd_bus_add_match(session->bus, NULL, str, pause_device, session);
+	if (ret < 0) {
+		wlr_log(L_ERROR, "Failed to add D-Bus match: %s", strerror(-ret));
+		return false;
+	}
+
+	snprintf(str, sizeof(str), fmt, "Session", "ResumeDevice", session->path);
+	ret = sd_bus_add_match(session->bus, NULL, str, resume_device, session);
+	if (ret < 0) {
+		wlr_log(L_ERROR, "Failed to add D-Bus match: %s", strerror(-ret));
+		return false;
+	}
+
+	return true;
+}
+
+static int dbus_event(int fd, uint32_t mask, void *data) {
+	sd_bus *bus = data;
+	while (sd_bus_process(bus, NULL) > 0);
+	return 1;
+}
+
+static struct wlr_session *logind_session_start(struct wl_display *disp) {
+	int ret;
+	struct logind_session *session = calloc(1, sizeof(*session));
+	if (!session) {
+		wlr_log(L_ERROR, "Allocation failed: %s", strerror(errno));
+		return NULL;
+	}
+
+	ret = sd_pid_get_session(getpid(), &session->id);
+	if (ret < 0) {
+		wlr_log(L_ERROR, "Failed to get session id: %s", strerror(-ret));
+		goto error;
+	}
+
+	ret = sd_session_get_vt(session->id, &session->base.vtnr);
+	if (ret < 0) {
+		wlr_log(L_ERROR, "Session not running in virtual terminal");
+		goto error;
+	}
+
+	char *seat;
+	ret = sd_session_get_seat(session->id, &seat);
+	if (ret < 0) {
+		wlr_log(L_ERROR, "Failed to get seat id: %s", strerror(-ret));
+		goto error;
+	}
+	snprintf(session->base.seat, sizeof(session->base.seat), "%s", seat);
+	free(seat);
+
+	ret = sd_bus_default_system(&session->bus);
+	if (ret < 0) {
+		wlr_log(L_ERROR, "Failed to open D-Bus connection: %s", strerror(-ret));
+		goto error;
+	}
+
+	if (!find_sesion_path(session)) {
+		sd_bus_unref(session->bus);
+		goto error;
+	}
+
+	if (!add_signal_matches(session)) {
+		goto error_bus;
+	}
+
+	struct wl_event_loop *event_loop = wl_display_get_event_loop(disp);
+	session->event = wl_event_loop_add_fd(event_loop, sd_bus_get_fd(session->bus),
+		WL_EVENT_READABLE, dbus_event, session->bus);
+
+	if (!session_activate(session)) {
+		goto error_bus;
+	}
+
+	if (!take_control(session)) {
+		goto error_bus;
+	}
+
+	wlr_log(L_INFO, "Successfully loaded logind session");
+
+	session->base.drm_fd = -1;
+	session->base.impl = &session_logind;
+	session->base.active = true;
+	wl_signal_init(&session->base.session_signal);
+	return &session->base;
+
+error_bus:
+	sd_bus_unref(session->bus);
+	free(session->path);
+
+error:
+	free(session->id);
+	return NULL;
+}
+
+const struct session_impl session_logind = {
+	.start = logind_session_start,
+	.finish = logind_session_finish,
+	.open = logind_take_device,
+	.close = logind_release_device,
+	.change_vt = logind_change_vt,
+};