Sample systemd unit file for Suricata.

Create a sample systemd unit file based on the build time
configuration.

Redmine issue:
https://redmine.openinfosecfoundation.org/issues/2138

configure.ac

@@ -2152,7 +2152,7 @@ AC_SUBST(CONFIGURE_SYSCONDIR)
 AC_SUBST(CONFIGURE_LOCALSTATEDIR)
 AC_SUBST(PACKAGE_VERSION)
 
-AC_OUTPUT(Makefile src/Makefile rust/Makefile rust/Cargo.toml rust/.cargo/config qa/Makefile qa/coccinelle/Makefile rules/Makefile doc/Makefile doc/userguide/Makefile contrib/Makefile contrib/file_processor/Makefile contrib/file_processor/Action/Makefile contrib/file_processor/Processor/Makefile contrib/tile_pcie_logd/Makefile suricata.yaml scripts/Makefile scripts/suricatasc/Makefile scripts/suricatasc/suricatasc etc/Makefile etc/suricata.logrotate)
+AC_OUTPUT(Makefile src/Makefile rust/Makefile rust/Cargo.toml rust/.cargo/config qa/Makefile qa/coccinelle/Makefile rules/Makefile doc/Makefile doc/userguide/Makefile contrib/Makefile contrib/file_processor/Makefile contrib/file_processor/Action/Makefile contrib/file_processor/Processor/Makefile contrib/tile_pcie_logd/Makefile suricata.yaml scripts/Makefile scripts/suricatasc/Makefile scripts/suricatasc/suricatasc etc/Makefile etc/suricata.logrotate etc/suricata.service)
 
 SURICATA_BUILD_CONF="Suricata Configuration:
   AF_PACKET support:                       ${enable_af_packet}

etc/Makefile.am

@@ -1 +1,2 @@
-EXTRA_DIST =	suricata.logrotate.in
+EXTRA_DIST =	suricata.logrotate.in \
+		suricata.service.in

etc/suricata.service.in

@@ -0,0 +1,16 @@
+# Sample Suricata systemd unit file.
+[Unit]
+Description=Suricata Intrusion Detection Service
+After=syslog.target network-online.target
+
+[Service]
+# Environment file to pick up $OPTIONS. On Fedora/EL this would be
+# /etc/sysconfig/suricata, or on Debian/Ubuntu, /etc/default/suricata.
+#EnvironmentFile=-/etc/sysconfig/suricata
+#EnvironmentFile=-/etc/default/suricata
+ExecStartPre=/bin/rm -f @e_rundir@suricata.pid
+ExecStart=/sbin/suricata -c @e_sysconfdir@suricata.yaml --pidfile @e_rundir@suricata.pid $OPTIONS
+ExecReload=/bin/kill -USR2 $MAINPID
+
+[Install]
+WantedBy=multi-user.target