compositor: systemd notifications support

Add systemd status and watchdog notification support.
Feature is not compiled by default and can be enabled by
"--enable-systemd-notify" configuration flag. It compiles
into module "systemd-notify.so" and can be loaded by
adding it in weston.ini like any other module, i.e.
"modules=systemd-notify.so". Watchdog timeout equals to
half of timeout defined by "WATCHDOG_USEC" environment
variable, which is set by "WatchdogSec=" setting in
service file.

Signed-off-by: Egor Starkov <egor.starkov@ge.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Reviewed-by: Bryce Harrington <bryce@osg.samsung.com>
Reviewed-by: Derek Foreman <derekf@osg.samsung.com>

Makefile.am

@@ -95,7 +95,24 @@ weston_SOURCES =					\
 	shared/timespec-util.h				\
 	shared/zalloc.h					\
 	shared/platform.h				\
-	src/weston-egl-ext.h
+	src/weston-egl-ext.h				\
+	src/systemd-notify.h
+
+if SYSTEMD_NOTIFY_SUPPORT
+module_LTLIBRARIES += systemd-notify.la
+systemd_notify_la_LDFLAGS = -module -avoid-version
+systemd_notify_la_LIBADD = $(SYSTEMD_DAEMON_LIBS)
+systemd_notify_la_CFLAGS =			\
+	$(SYSTEMD_DAEMON_LIBS)			\
+	$(PIXMAN_CFLAGS)			\
+	$(AM_CFLAGS)
+systemd_notify_la_SOURCES =			\
+	src/systemd-notify.c			\
+	src/systemd-notify.h			\
+	shared/helpers.h			\
+	shared/zalloc.h				\
+	compositor.h
+endif
 
 nodist_weston_SOURCES =					\
 	protocol/screenshooter-protocol.c		\

configure.ac

@@ -565,6 +565,18 @@ if test x$wayland_scanner = x; then
 	wayland_scanner=`$PKG_CONFIG --variable=wayland_scanner wayland-scanner`
 fi
 
+AC_ARG_ENABLE(systemd_notify,
+              AS_HELP_STRING([--enable-systemd-notify],
+                             [Enables systemd notifications to
+                              notify systemd about weston state
+                              and update watchdog.]),,
+              enable_systemd_notify=no)
+AM_CONDITIONAL(SYSTEMD_NOTIFY_SUPPORT, test x$enable_systemd_notify = xyes)
+if test "x$enable_systemd_notify" = "xyes"; then
+  AC_DEFINE([SYSTEMD_NOTIFY_SUPPORT], [1], [Build the systemd sd_notify support])
+  PKG_CHECK_MODULES(SYSTEMD_DAEMON, [libsystemd])
+fi
+
 AC_CONFIG_FILES([Makefile src/version.h src/weston.pc])
 
 AM_CONDITIONAL([HAVE_GIT_REPO], [test -f $srcdir/.git/logs/HEAD])
@@ -590,6 +602,7 @@ AC_MSG_RESULT([
 
 	weston-launch utility		${enable_weston_launch}
 	systemd-login support		${have_systemd_login}
+	systemd notify support		${enable_systemd_notify}
 
 	DRM Compositor			${enable_drm_compositor}
 	X11 Compositor			${enable_x11_compositor}

src/main.c

@@ -46,6 +46,7 @@
 #include "../shared/helpers.h"
 #include "git-version.h"
 #include "version.h"
+#include "systemd-notify.h"
 
 static struct wl_list child_process_list;
 static struct weston_compositor *segv_compositor;

src/systemd-notify.c

@@ -0,0 +1,123 @@
+/*
+ * Copyright (c) 2015 General Electric Company. All rights reserved.
+ *
+ * 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.
+ */
+
+#include "config.h"
+
+#include <errno.h>
+#include <stdlib.h>
+#include <systemd/sd-daemon.h>
+#include <wayland-server.h>
+#include "shared/helpers.h"
+#include "shared/zalloc.h"
+#include "compositor.h"
+
+struct systemd_notifier {
+	int watchdog_time;
+	struct wl_event_source *watchdog_source;
+	struct wl_listener compositor_destroy_listener;
+};
+
+static int
+watchdog_handler(void *data)
+{
+	struct systemd_notifier *notifier = data;
+
+	wl_event_source_timer_update(notifier->watchdog_source,
+				     notifier->watchdog_time);
+
+	sd_notify(0, "WATCHDOG=1");
+
+	return 1;
+}
+
+static void
+weston_compositor_destroy_listener(struct wl_listener *listener, void *data)
+{
+	struct systemd_notifier *notifier;
+
+	sd_notify(0, "STOPPING=1");
+
+	notifier = container_of(listener,
+				struct systemd_notifier,
+				compositor_destroy_listener);
+
+	if (notifier->watchdog_source)
+		wl_event_source_remove(notifier->watchdog_source);
+
+	wl_list_remove(&notifier->compositor_destroy_listener.link);
+	free(notifier);
+}
+
+WL_EXPORT int
+module_init(struct weston_compositor *compositor,
+	    int *argc, char *argv[])
+{
+	char *tail;
+	char *watchdog_time_env;
+	struct wl_event_loop *loop;
+	long watchdog_time_conv;
+	struct systemd_notifier *notifier;
+
+	notifier = zalloc(sizeof *notifier);
+	if (notifier == NULL)
+		return -1;
+
+	notifier->compositor_destroy_listener.notify =
+		weston_compositor_destroy_listener;
+	wl_signal_add(&compositor->destroy_signal,
+		      &notifier->compositor_destroy_listener);
+
+	sd_notify(0, "READY=1");
+
+	/* 'WATCHDOG_USEC' is environment variable that is set
+	 * by systemd to transfer 'WatchdogSec' watchdog timeout
+	 * setting from service file.*/
+	watchdog_time_env = getenv("WATCHDOG_USEC");
+
+	if (!watchdog_time_env)
+		return 0;
+
+	errno = 0;
+	watchdog_time_conv = strtol(watchdog_time_env, &tail, 0);
+	if ((errno != 0) || (*tail != '\0'))
+		return 0;
+
+	/* Convert 'WATCHDOG_USEC' to milliseconds and notify
+	 * systemd every half of that time.*/
+	watchdog_time_conv /= 1000 * 2;
+	if (watchdog_time_conv <= 0)
+		return 0;
+
+	notifier->watchdog_time = watchdog_time_conv;
+
+	loop = wl_display_get_event_loop(compositor->wl_display);
+	notifier->watchdog_source =
+		wl_event_loop_add_timer(loop, watchdog_handler, notifier);
+	wl_event_source_timer_update(notifier->watchdog_source,
+				     notifier->watchdog_time);
+
+	return 0;
+}
+

src/systemd-notify.h

@@ -0,0 +1,47 @@
+/*
+ * Copyright (c) 2015 General Electric Company. All rights reserved.
+ *
+ * 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.
+ */
+
+#ifndef _SYSTEMD_NOTIFY_H_
+#define _SYSTEMD_NOTIFY_H_
+
+#include "config.h"
+
+#ifdef SYSTEMD_NOTIFY_SUPPORT
+
+struct weston_compositor;
+
+void
+weston_systemd_service_start(struct weston_compositor *compositor);
+
+#else
+
+static inline void
+weston_systemd_service_start(struct weston_compositor *compositor)
+{
+}
+
+#endif //SYSTEMD_NOTIFY_SUPPORT
+
+#endif //_SYSTEMD_NOTIFY_H_