Improve systemd integration

When fluidsynth is run as a service using systemd, make sure
the service is considered started only when it is ready to process events.

In order to do so:
 - Add an optional runtime dependency to libsystemd to the fluidsynth executable
 - Change the systemd service type to "notify"
 - Have fluidsynth notify systemd that the service is started after the server is started
 - Have fluidsynth notify systemd that the service is stopping after joining the server thread

CMakeLists.txt

@@ -80,6 +80,10 @@ if ( CMAKE_SYSTEM MATCHES "Linux|FreeBSD|DragonFly" )
     option ( enable-alsa "compile ALSA support (if it is available)" on )
 endif ( CMAKE_SYSTEM MATCHES "Linux|FreeBSD|DragonFly" )
 
+if ( CMAKE_SYSTEM MATCHES "Linux" )
+    option ( enable-systemd "compile systemd support (if it is available)" on )
+endif ( CMAKE_SYSTEM MATCHES "Linux" )
+
 if ( CMAKE_SYSTEM MATCHES "Darwin" )
     option ( enable-coreaudio "compile CoreAudio support (if it is available)" on )
     option ( enable-coremidi "compile CoreMIDI support (if it is available)" on )
@@ -521,6 +525,14 @@ else(NOT enable-pkgconfig)
     remove_definitions( -DHAVE_LASH )
     endif ( enable-lash )
 
+    unset ( SYSTEMD_SUPPORT CACHE )
+    if ( enable-systemd )
+        pkg_check_modules ( SYSTEMD libsystemd )
+        set ( SYSTEMD_SUPPORT ${SYSTEMD_FOUND} )
+    else ( enable-systemd )
+        unset_pkg_config ( SYSTEMD )
+    endif ( enable-systemd )
+
     unset ( DBUS_SUPPORT CACHE )
     if ( enable-dbus )
     pkg_check_modules ( DBUS dbus-1>=1.0.0 )

cmake_admin/report.cmake

@@ -98,6 +98,12 @@ else ( LASH_SUPPORT )
   message ( "LASH support:          no" )
 endif ( LASH_SUPPORT )
 
+if ( SYSTEMD_SUPPORT )
+  message ( "systemd support:       yes" )
+else ( SYSTEMD_SUPPORT )
+  message ( "systemd support:       no" )
+endif ( SYSTEMD_SUPPORT )
+
 if ( DART_SUPPORT )
   message ( "OS/2 DART support:     yes" )
 else ( DART_SUPPORT )

fluidsynth.service.in

@@ -4,6 +4,8 @@ Documentation=man:fluidsynth(1)
 After=sound.target
 
 [Service]
+Type=notify
+NotifyAccess=main
 EnvironmentFile=@FLUID_DAEMON_ENV_FILE@
 EnvironmentFile=-%h/.config/fluidsynth
 ExecStart=@CMAKE_INSTALL_PREFIX@/@BIN_INSTALL_DIR@/fluidsynth -is $OTHER_OPTS $SOUND_FONT

src/CMakeLists.txt

@@ -95,6 +95,10 @@ if ( LASH_SUPPORT )
   include_directories ( ${LASH_INCLUDE_DIRS})
 endif ( LASH_SUPPORT )
 
+if ( SYSTEMD_SUPPORT )
+  include_directories ( ${SYSTEMD_INCLUDE_DIRS})
+endif ( SYSTEMD_SUPPORT )
+
 if ( DART_SUPPORT )
   set ( fluid_dart_SOURCES drivers/fluid_dart.c )
   include_directories ( ${DART_INCLUDE_DIRS} )
@@ -341,6 +345,7 @@ endif ( FLUID_CPPFLAGS )
 
 target_link_libraries ( fluidsynth
     libfluidsynth
+    ${SYSTEMD_LIBRARIES}
     ${FLUID_LIBS}
 )
 

src/config.cmake

@@ -49,6 +49,9 @@
 /* whether or not we are supporting lash */
 #cmakedefine HAVE_LASH @HAVE_LASH@
 
+/* Define if systemd support is enabled */
+#cmakedefine SYSTEMD_SUPPORT @SYSTEMD_SUPPORT@
+
 /* Define to 1 if you have the `MidiShare' library (-lMidiShare). */
 #cmakedefine HAVE_LIBMIDISHARE @HAVE_LIBMIDISHARE@
 

src/fluidsynth.c

@@ -31,6 +31,9 @@
 
 #include "fluid_lash.h"
 
+#ifdef SYSTEMD_SUPPORT
+#include <systemd/sd-daemon.h>
+#endif
 
 void print_usage(void);
 void print_help(fluid_settings_t *settings);
@@ -892,6 +895,12 @@ int main(int argc, char **argv)
             fprintf(stderr, "Failed to create the server.\n"
                     "Continuing without it.\n");
         }
+#ifdef SYSTEMD_SUPPORT
+        else
+        {
+            sd_notify(0, "READY=1");
+        }
+#endif
     }
 
 #endif
@@ -954,10 +963,13 @@ cleanup:
             fluid_server_join(server);
         }
 
+#ifdef SYSTEMD_SUPPORT
+        sd_notify(0, "STOPPING=1");
+#endif
         delete_fluid_server(server);
     }
 
-#endif
+#endif	/* NETWORK_SUPPORT */
 
     if(cmd_handler != NULL)
     {