share/mainloop: Add handling of NOTIFY_SOCKET

This adds handling of systemd NOTIFY_SOCKET so application using
mainloop instance do properly notify systemd what is their state.

Makefile.am

@@ -190,12 +190,16 @@ endif
 src_libshared_glib_la_SOURCES = $(shared_sources) \
 				src/shared/io-glib.c \
 				src/shared/timeout-glib.c \
-				src/shared/mainloop-glib.c
+				src/shared/mainloop-glib.c \
+				src/shared/mainloop-notify.h \
+				src/shared/mainloop-notify.c
 
 src_libshared_mainloop_la_SOURCES = $(shared_sources) \
 				src/shared/io-mainloop.c \
 				src/shared/timeout-mainloop.c \
-				src/shared/mainloop.h src/shared/mainloop.c
+				src/shared/mainloop.h src/shared/mainloop.c \
+				src/shared/mainloop-notify.h \
+				src/shared/mainloop-notify.c
 
 if LIBSHARED_ELL
 noinst_LTLIBRARIES += src/libshared-ell.la

src/shared/mainloop-glib.c

@@ -36,6 +36,7 @@
 #include <glib.h>
 
 #include "mainloop.h"
+#include "mainloop-notify.h"
 
 static GMainLoop *main_loop;
 static int exit_status;
@@ -43,6 +44,7 @@ static int exit_status;
 void mainloop_init(void)
 {
 	main_loop = g_main_loop_new(NULL, FALSE);
+	mainloop_notify_init();
 }
 
 void mainloop_quit(void)
@@ -51,6 +53,8 @@ void mainloop_quit(void)
 		return;
 
 	g_main_loop_quit(main_loop);
+
+	mainloop_sd_notify("STOPPING=1");
 }
 
 void mainloop_exit_success(void)
@@ -75,6 +79,8 @@ int mainloop_run(void)
 	g_main_loop_unref(main_loop);
 	main_loop = NULL;
 
+	mainloop_notify_exit();
+
 	return exit_status;
 }
 

src/shared/mainloop-notify.c

@@ -0,0 +1,93 @@
+/*
+ *
+ *  BlueZ - Bluetooth protocol stack for Linux
+ *
+ *  Copyright (C) 2018  Intel Corporation. All rights reserved.
+ *
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2.1 of the License, or (at your option) any later version.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, write to the Free Software
+ *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <stdio.h>
+#include <errno.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <stddef.h>
+#include <string.h>
+
+#include <sys/socket.h>
+#include <sys/un.h>
+
+#include "mainloop.h"
+#include "mainloop-notify.h"
+
+static int notify_fd = -1;
+
+void mainloop_notify_init(void)
+{
+	const char *sock;
+	struct sockaddr_un addr;
+
+	sock = getenv("NOTIFY_SOCKET");
+	if (!sock)
+		return;
+
+	/* check for abstract socket or absolute path */
+	if (sock[0] != '@' && sock[0] != '/')
+		return;
+
+	notify_fd = socket(AF_UNIX, SOCK_DGRAM | SOCK_CLOEXEC, 0);
+	if (notify_fd < 0)
+		return;
+
+	memset(&addr, 0, sizeof(addr));
+	addr.sun_family = AF_UNIX;
+	strncpy(addr.sun_path, sock, sizeof(addr.sun_path) - 1);
+
+	if (addr.sun_path[0] == '@')
+		addr.sun_path[0] = '\0';
+
+	if (bind(notify_fd, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
+		close(notify_fd);
+		notify_fd = -1;
+	}
+}
+
+void mainloop_notify_exit(void)
+{
+	if (notify_fd > 0) {
+		close(notify_fd);
+		notify_fd = -1;
+	}
+}
+
+int mainloop_sd_notify(const char *state)
+{
+	int err;
+
+	if (notify_fd <= 0)
+		return -ENOTCONN;
+
+	err = send(notify_fd, state, strlen(state), MSG_NOSIGNAL);
+	if (err < 0)
+		return -errno;
+
+	return err;
+}

src/shared/mainloop-notify.h

@@ -0,0 +1,25 @@
+/*
+ *
+ *  BlueZ - Bluetooth protocol stack for Linux
+ *
+ *  Copyright (C) 2018  Intel Corporation. All rights reserved.
+ *
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2.1 of the License, or (at your option) any later version.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, write to the Free Software
+ *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ */
+
+void mainloop_notify_init(void);
+void mainloop_notify_exit(void);

src/shared/mainloop.c

@@ -30,13 +30,17 @@
 #include <errno.h>
 #include <unistd.h>
 #include <stdlib.h>
+#include <stddef.h>
 #include <string.h>
 #include <signal.h>
 #include <sys/signalfd.h>
 #include <sys/timerfd.h>
 #include <sys/epoll.h>
+#include <sys/socket.h>
+#include <sys/un.h>
 
 #include "mainloop.h"
+#include "mainloop-notify.h"
 
 #define MAX_EPOLL_EVENTS 10
 
@@ -83,11 +87,15 @@ void mainloop_init(void)
 		mainloop_list[i] = NULL;
 
 	epoll_terminate = 0;
+
+	mainloop_notify_init();
 }
 
 void mainloop_quit(void)
 {
 	epoll_terminate = 1;
+
+	mainloop_sd_notify("STOPPING=1");
 }
 
 void mainloop_exit_success(void)
@@ -183,6 +191,8 @@ int mainloop_run(void)
 	close(epoll_fd);
 	epoll_fd = 0;
 
+	mainloop_notify_exit();
+
 	return exit_status;
 }
 

src/shared/mainloop.h

@@ -49,3 +49,4 @@ int mainloop_remove_timeout(int id);
 
 int mainloop_set_signal(sigset_t *mask, mainloop_signal_func callback,
 				void *user_data, mainloop_destroy_func destroy);
+int mainloop_sd_notify(const char *state);