Add systemd unit file to start X52 daemon

INSTALL.md

@@ -77,3 +77,21 @@ the following argument to `configure`:
 ```
 --with-input-group=group
 ```
+
+### Systemd support
+
+The X52 daemon can run either as a foreground process, or it can daemonize
+itself to run in the background. Typical deployments with systemd will have it
+run in the foreground, and disable timestamps in the logs, since those are
+inserted automatically by journald.
+
+Systemd support is enabled by default, but can be disabled with the
+`--disable-systemd` argument to `configure`
+
+It is also possible to configure the directory in which the service file is
+installed with the following option. This is ignored if you have specified
+`--disable-systemd`.
+
+```
+--with-systemdsystemunitdir=/path/to/systemd/system
+```

configure.ac

@@ -11,6 +11,7 @@ AC_REQUIRE_AUX_FILE([tap-driver.sh])
 AC_PROG_CC
 AC_PROG_CC_STDC
 AC_PROG_AWK
+AC_PROG_SED
 AM_PROG_AR
 AM_PATH_PYTHON([3.5])
 LT_INIT
@@ -51,9 +52,29 @@ PKG_CHECK_MODULES([INIH], [inih], [],
                     AC_SEARCH_LIBS([ini_parse], [inih])
                   ])
 
-# Pinelog configuration
-AC_SUBST([PINELOG_CFLAGS], ["-DPINELOG_SHOW_DATE=1 -DPINELOG_SHOW_LEVEL=1 -DPINELOG_SHOW_BACKTRACE=1"])
+# systemd support
+PKG_CHECK_MODULES([SYSTEMD], [systemd], [have_systemd=yes], [have_systemd=no])
+AC_ARG_ENABLE([systemd],
+    [AS_HELP_STRING([--disable-systemd], [Disable systemd support])]
+)
+AC_ARG_WITH([systemdsystemunitdir],
+    [AS_HELP_STRING([--with-systemdsystemunitdir=DIR], [Directory for systemd unit files])],
+    [systemdsystemunitdir=$withval],
+    [systemdsystemunitdir=$($PKG_CONFIG --variable=systemdsystemunitdir systemd)]
+)
+AC_SUBST([systemdsystemunitdir], [$systemdsystemunitdir])
+AM_CONDITIONAL([HAVE_SYSTEMD], [test "x$have_systemd" = "xyes" -a "x$enable_systemd" != "xno"])
+AM_COND_IF([HAVE_SYSTEMD],,
+        [
+         AC_MSG_NOTICE([systemd not found or disabled. Enabling timestamps in logs])
+         AX_APPEND_FLAG([-DPINELOG_SHOW_DATE=1], [PINELOG_CFLAGS])
+        ]
+)
 
+# Pinelog configuration
+AX_APPEND_FLAG([-DPINELOG_SHOW_LEVEL=1], [PINELOG_CFLAGS])
+AX_APPEND_FLAG([-DPINELOG_SHOW_BACKTRACE=1], [PINELOG_CFLAGS])
+AC_SUBST([PINELOG_CFLAGS])
 
 # Check for hidapi. This uses a different pkg-config file on Linux vs other
 # hosts, so check accordingly

daemon/Makefile.am

@@ -37,9 +37,19 @@ x52dconf_DATA = daemon/x52d.conf
 
 EXTRA_DIST += \
 	daemon/daemon.dox \
+	daemon/x52d.service.in \
 	daemon/x52d_clock.h \
 	daemon/x52d_config.def \
 	daemon/x52d_config.h \
 	daemon/x52d_const.h \
 	daemon/x52d_device.h \
 	daemon/x52d.conf
+
+if HAVE_SYSTEMD
+if !IS_MAKE_DISTCHECK
+SED_ARGS = s,%bindir%,$(bindir),g
+x52d.service: daemon/x52d.service.in
+	$(AM_V_GEN) $(SED) -e '$(SED_ARGS)' $< > $@
+systemdsystemunit_DATA = x52d.service
+endif
+endif

daemon/x52d.service.in

@@ -0,0 +1,7 @@
+[Unit]
+Description=X52 driver daemon
+
+[Service]
+Type=simple
+ExecStart=%bindir%/x52d -f
+ExecReload=kill -HUP $MAINPID