[471053] Add systemd support and services.

Add possibility to notify systemd that service is fully started. Also add
reference service files.

Change-Id: Ib4e39c8406ab6c15e1b88f197ae8f91c3e402023
Bug: https://bugs.eclipse.org/bugs/show_bug.cgi?id=471053
Signed-off-by: Tomas Novotny <novotny@rehivetech.com>

ChangeLog.txt

@@ -17,6 +17,7 @@ Broker:
 - Add use_subject_as_username option for certificate based client
   authentication to use the entire certificate subject as a username, rather
   than just the CN. Closes #469467.
+- Add systemd startup notification and services. Closes #471053.
 
 Client library:
 - Outgoing messages with QoS>1 are no longer retried after a timeout period.

compiling.txt

@@ -4,6 +4,7 @@ The following packages are required for mosquitto:
 * openssl (version 1.0.0 or greater if TLS-PSK support is needed, can be disabled)
 * c-ares (for DNS-SRV support, can be disabled)
 * libuuid (from e2fsprogs, can be disabled)
+* libsystemd (optional, disabled by default)
 * On Windows, the Redhat pthreads library is required if threading support is
   to be included.
 

config.mk

@@ -57,6 +57,10 @@ WITH_MEMORY_TRACKING:=yes
 # information about the broker state.
 WITH_SYS_TREE:=yes
 
+# Build with systemd support. If enabled, mosquitto will notify systemd after
+# initialization. See README in service/systemd/ for more information.
+WITH_SYSTEMD:=no
+
 # Build with SRV lookup support.
 WITH_SRV:=yes
 
@@ -215,6 +219,11 @@ ifeq ($(WITH_SYS_TREE),yes)
 	BROKER_CFLAGS:=$(BROKER_CFLAGS) -DWITH_SYS_TREE
 endif
 
+ifeq ($(WITH_SYSTEMD),yes)
+	BROKER_CFLAGS:=$(BROKER_CFLAGS) -DWITH_SYSTEMD
+	BROKER_LIBS:=$(BROKER_LIBS) -lsystemd
+endif
+
 ifeq ($(WITH_SRV),yes)
 	LIB_CFLAGS:=$(LIB_CFLAGS) -DWITH_SRV
 	LIB_LIBS:=$(LIB_LIBS) -lcares

service/systemd/README

@@ -0,0 +1,8 @@
+Select appropriate systemd service based on your compile settings. If you
+enabled WITH_SYSTEMD, use mosquitto.service.notify, otherwise use
+mosquitto.service.simple. The service must be renamed to mosquitto.service
+before usage.
+
+With WITH_SYSTEMD mosquitto will notify a complete startup after
+initialization. This means that follow-up units can be started after full
+initialization of mosquitto (i.e. sockets are opened).

service/systemd/mosquitto.service.notify

@@ -0,0 +1,11 @@
+[Unit]
+Description=Mosquitto MQTT v3.1/v3.1.1 Broker
+
+[Service]
+Type=notify
+NotifyAccess=main
+ExecStart=/usr/sbin/mosquitto
+Restart=on-failure
+
+[Install]
+WantedBy=multi-user.target

service/systemd/mosquitto.service.simple

@@ -0,0 +1,9 @@
+[Unit]
+Description=Mosquitto MQTT v3.1/v3.1.1 Broker
+
+[Service]
+ExecStart=/usr/sbin/mosquitto
+Restart=on-failure
+
+[Install]
+WantedBy=multi-user.target

src/CMakeLists.txt

@@ -67,6 +67,16 @@ if (${WITH_SYS_TREE} STREQUAL ON)
 	add_definitions("-DWITH_SYS_TREE")
 endif (${WITH_SYS_TREE} STREQUAL ON)
 
+if (CMAKE_SYSTEM_NAME STREQUAL Linux)
+	option(WITH_SYSTEMD
+		"Include systemd support?" OFF)
+	if (${WITH_SYSTEMD} STREQUAL ON)
+		add_definitions("-DWITH_SYSTEMD")
+		find_library(SYSTEMD_LIBRARY systemd)
+		set (MOSQ_LIBS ${MOSQ_LIBS} ${SYSTEMD_LIBRARY})
+	endif (${WITH_SYSTEMD} STREQUAL ON)
+endif (CMAKE_SYSTEM_NAME STREQUAL Linux)
+
 option(WITH_WEBSOCKETS
 	"Include websockets support?" OFF)
 if (${WITH_WEBSOCKETS} STREQUAL ON)

src/mosquitto.c

@@ -39,6 +39,9 @@ Contributors:
 #include <signal.h>
 #include <stdio.h>
 #include <string.h>
+#ifdef WITH_SYSTEMD
+#  include <systemd/sd-daemon.h>
+#endif
 #ifdef WITH_WRAP
 #include <tcpd.h>
 #endif
@@ -362,6 +365,10 @@ int main(int argc, char *argv[])
 	}
 #endif
 
+#ifdef WITH_SYSTEMD
+	sd_notify(0, "READY=1");
+#endif
+
 	run = 1;
 	rc = mosquitto_main_loop(&int_db, listensock, listensock_count, listener_max);