Add native systemd service

Inspired by: https://github.com/pi-hole/pi-hole/pull/2112

A pre-start and a post-stop script are added to reduce doubled setup and cleanup code.

Since systemd services do not natively support dynamic users, test once whether capabilities are supported during install/update, and remove User=pihole otherwise.

Signed-off-by: MichaIng <micha@dietpi.com>
Co-authored-by: DL6ER <dl6er@dl6er.de>

advanced/Templates/pihole-FTL-poststop.sh

@@ -0,0 +1,13 @@
+#!/usr/bin/env sh
+
+# Source utils.sh for getFTLPIDFile()
+PI_HOLE_SCRIPT_DIR='/opt/pihole'
+utilsfile="${PI_HOLE_SCRIPT_DIR}/utils.sh"
+# shellcheck disable=SC1090
+. "${utilsfile}"
+
+# Get file paths
+FTL_PID_FILE="$(getFTLPIDFile)"
+
+# Cleanup
+rm -f /run/pihole/FTL.sock /dev/shm/FTL-* "${FTL_PID_FILE}"

advanced/Templates/pihole-FTL-prestart.sh

@@ -0,0 +1,38 @@
+#!/usr/bin/env sh
+
+# Source utils.sh for getFTLPIDFile()
+PI_HOLE_SCRIPT_DIR='/opt/pihole'
+utilsfile="${PI_HOLE_SCRIPT_DIR}/utils.sh"
+# shellcheck disable=SC1090
+. "${utilsfile}"
+
+# Get file paths
+FTL_PID_FILE="$(getFTLPIDFile)"
+
+# Touch files to ensure they exist (create if non-existing, preserve if existing)
+# shellcheck disable=SC2174
+mkdir -pm 0755 /run/pihole /var/log/pihole
+[ -f "${FTL_PID_FILE}" ] || install -D -m 644 -o pihole -g pihole /dev/null "${FTL_PID_FILE}"
+[ -f /var/log/pihole/FTL.log ] || install -m 644 -o pihole -g pihole /dev/null /var/log/pihole/FTL.log
+[ -f /var/log/pihole/pihole.log ] || install -m 640 -o pihole -g pihole /dev/null /var/log/pihole/pihole.log
+[ -f /etc/pihole/dhcp.leases ] || install -m 644 -o pihole -g pihole /dev/null /etc/pihole/dhcp.leases
+# Ensure that permissions are set so that pihole-FTL can edit all necessary files
+chown pihole:pihole /run/pihole /etc/pihole /var/log/pihole /var/log/pihole/FTL.log /var/log/pihole/pihole.log /etc/pihole/dhcp.leases
+# Ensure that permissions are set so that pihole-FTL can edit the files. We ignore errors as the file may not (yet) exist
+chmod -f 0644 /etc/pihole/macvendor.db /etc/pihole/dhcp.leases /var/log/pihole/FTL.log
+chmod -f 0640 /var/log/pihole/pihole.log
+# Chown database files to the user FTL runs as. We ignore errors as the files may not (yet) exist
+chown -f pihole:pihole /etc/pihole/pihole-FTL.db /etc/pihole/gravity.db /etc/pihole/macvendor.db
+# Chmod database file permissions so that the pihole group (web interface) can edit the file. We ignore errors as the files may not (yet) exist
+chmod -f 0664 /etc/pihole/pihole-FTL.db
+
+# Backward compatibility for user-scripts that still expect log files in /var/log instead of /var/log/pihole
+# Should be removed with Pi-hole v6.0
+if [ ! -f /var/log/pihole.log ]; then
+    ln -sf /var/log/pihole/pihole.log /var/log/pihole.log
+    chown -h pihole:pihole /var/log/pihole.log
+fi
+if [ ! -f /var/log/pihole-FTL.log ]; then
+    ln -sf /var/log/pihole/FTL.log /var/log/pihole-FTL.log
+    chown -h pihole:pihole /var/log/pihole-FTL.log
+fi

advanced/Templates/pihole-FTL.service

@@ -9,9 +9,10 @@
 # Description:       Enable service provided by pihole-FTL daemon
 ### END INIT INFO
 
-#source utils.sh for getFTLPIDFile(), getFTLPID ()
+# Source utils.sh for getFTLPIDFile(), getFTLPID()
 PI_HOLE_SCRIPT_DIR="/opt/pihole"
 utilsfile="${PI_HOLE_SCRIPT_DIR}/utils.sh"
+# shellcheck disable=SC1090
 . "${utilsfile}"
 
 
@@ -28,33 +29,8 @@ start() {
   if is_running; then
     echo "pihole-FTL is already running"
   else
-    # Touch files to ensure they exist (create if non-existing, preserve if existing)
-    mkdir -pm 0755 /run/pihole /var/log/pihole
-    [ ! -f "${FTL_PID_FILE}" ] && install -D -m 644 -o pihole -g pihole /dev/null "${FTL_PID_FILE}"
-    [ ! -f /var/log/pihole/FTL.log ] && install -m 644 -o pihole -g pihole /dev/null /var/log/pihole/FTL.log
-    [ ! -f /var/log/pihole/pihole.log ] && install -m 640 -o pihole -g pihole /dev/null /var/log/pihole/pihole.log
-    [ ! -f /etc/pihole/dhcp.leases ] && install -m 644 -o pihole -g pihole /dev/null /etc/pihole/dhcp.leases
-    # Ensure that permissions are set so that pihole-FTL can edit all necessary files
-    chown pihole:pihole /run/pihole /etc/pihole /var/log/pihole /var/log/pihole/FTL.log /var/log/pihole/pihole.log /etc/pihole/dhcp.leases
-    # Ensure that permissions are set so that pihole-FTL can edit the files. We ignore errors as the file may not (yet) exist
-    chmod -f 0644 /etc/pihole/macvendor.db /etc/pihole/dhcp.leases /var/log/pihole/FTL.log
-    chmod -f 0640 /var/log/pihole/pihole.log
-    # Chown database files to the user FTL runs as. We ignore errors as the files may not (yet) exist
-    chown -f pihole:pihole /etc/pihole/pihole-FTL.db /etc/pihole/gravity.db /etc/pihole/macvendor.db
-    # Chown database file permissions so that the pihole group (web interface) can edit the file. We ignore errors as the files may not (yet) exist
-    chmod -f 0664 /etc/pihole/pihole-FTL.db
-
-    # Backward compatibility for user-scripts that still expect log files in /var/log instead of /var/log/pihole/
-    # Should be removed with Pi-hole v6.0
-    if [ ! -f /var/log/pihole.log ]; then
-        ln -s /var/log/pihole/pihole.log /var/log/pihole.log
-        chown -h pihole:pihole /var/log/pihole.log
-
-    fi
-    if [ ! -f /var/log/pihole-FTL.log ]; then
-        ln -s /var/log/pihole/FTL.log /var/log/pihole-FTL.log
-        chown -h pihole:pihole /var/log/pihole-FTL.log
-    fi
+    # Run pre-start script, which pre-creates all expected files with correct permissions
+    sh "${PI_HOLE_SCRIPT_DIR}/pihole-FTL-prestart.sh"
 
     if setcap CAP_NET_BIND_SERVICE,CAP_NET_RAW,CAP_NET_ADMIN,CAP_SYS_NICE,CAP_IPC_LOCK,CAP_CHOWN+eip "/usr/bin/pihole-FTL"; then
       su -s /bin/sh -c "/usr/bin/pihole-FTL" pihole || exit $?
@@ -89,8 +65,8 @@ stop() {
   else
     echo "Not running"
   fi
-  # Cleanup
-  rm -f /run/pihole/FTL.sock /dev/shm/FTL-* "${FTL_PID_FILE}"
+  # Run post-stop script, which does cleanup among runtime files
+  sh "${PI_HOLE_SCRIPT_DIR}/pihole-FTL-poststop.sh"
   echo
 }
 
@@ -108,11 +84,11 @@ status() {
 
 ### main logic ###
 
-# Get file paths
+# Get FTL's PID file path
 FTL_PID_FILE="$(getFTLPIDFile)"
 
 # Get FTL's current PID
-FTL_PID="$(getFTLPID ${FTL_PID_FILE})"
+FTL_PID="$(getFTLPID "${FTL_PID_FILE}")"
 
 case "$1" in
   stop)

advanced/Templates/pihole-FTL.systemd

@@ -0,0 +1,41 @@
+[Unit]
+Description=Pi-hole FTL
+# This unit is supposed to indicate when network functionality is available, but it is only
+# very weakly defined what that is supposed to mean, with one exception: at shutdown, a unit
+# that is ordered after network-online.target will be stopped before the network
+Wants=network-online.target
+After=network-online.target
+# A target that should be used as synchronization point for all host/network name service lookups.
+# All services for which the availability of full host/network name resolution is essential should
+# be ordered after this target, but not pull it in.
+Wants=nss-lookup.target
+Before=nss-lookup.target
+
+# Limit (re)start loop to 5 within 1 minute
+StartLimitBurst=5
+StartLimitIntervalSec=60s
+
+[Service]
+User=pihole
+PermissionsStartOnly=true
+AmbientCapabilities=CAP_NET_BIND_SERVICE CAP_NET_RAW CAP_NET_ADMIN CAP_SYS_NICE CAP_IPC_LOCK CAP_CHOWN
+
+ExecStartPre=/opt/pihole/pihole-FTL-prestart.sh
+ExecStart=/usr/bin/pihole-FTL -f
+Restart=on-failure
+RestartSec=5s
+ExecReload=/bin/kill -HUP $MAINPID
+ExecStopPost=/opt/pihole/pihole-FTL-poststop.sh
+
+# Use graceful shutdown with a reasonable timeout
+TimeoutStopSec=10s
+
+# Make /usr, /boot, /etc and possibly some more folders read-only...
+ProtectSystem=full
+# ... except /etc/pihole
+# This merely retains r/w access rights, it does not add any new.
+# Must still be writable on the host!
+ReadWriteDirectories=/etc/pihole
+
+[Install]
+WantedBy=multi-user.target

automated install/basic-install.sh

@@ -1377,8 +1377,29 @@ installConfigs() {
         fi
     fi
 
-    # Install pihole-FTL.service
-    install -T -m 0755 "${PI_HOLE_LOCAL_REPO}/advanced/Templates/pihole-FTL.service" "/etc/init.d/pihole-FTL"
+    # Install pihole-FTL systemd or init.d service, based on whether systemd is the init system or not
+    # Follow debhelper logic, which checks for /run/systemd/system to derive whether systemd is the init system
+    if [[ -d '/run/systemd/system' ]]; then
+        install -T -m 0644 "${PI_HOLE_LOCAL_REPO}/advanced/Templates/pihole-FTL.systemd" '/etc/systemd/system/pihole-FTL.service'
+
+        # Set net admin permissions so that FTL can serve DNS, DHCP and IMAP (for DHCPv6). If this does not work, run FTL as root user.
+        if ! setcap CAP_NET_BIND_SERVICE,CAP_NET_RAW,CAP_NET_ADMIN,CAP_SYS_NICE,CAP_IPC_LOCK,CAP_CHOWN+eip '/usr/bin/pihole-FTL'; then
+            sed -i '/^User=/d' '/etc/systemd/system/pihole-FTL.service'
+        fi
+
+        # Remove init.d service if present
+        if [[ -e '/etc/init.d/pihole-FTL' ]]; then
+            rm '/etc/init.d/pihole-FTL'
+            update-rc.d pihole-FTL remove
+        fi
+
+        # Load final service
+        systemctl daemon-reload
+    else
+        install -T -m 0755 "${PI_HOLE_LOCAL_REPO}/advanced/Templates/pihole-FTL.service" '/etc/init.d/pihole-FTL'
+    fi
+    install -T -m 0755 "${PI_HOLE_LOCAL_REPO}/advanced/Templates/pihole-FTL-prestart.sh" "${PI_HOLE_INSTALL_DIR}/pihole-FTL-prestart.sh"
+    install -T -m 0755 "${PI_HOLE_LOCAL_REPO}/advanced/Templates/pihole-FTL-poststop.sh" "${PI_HOLE_INSTALL_DIR}/pihole-FTL-poststop.sh"
 
     # If the user chose to install the dashboard,
     if [[ "${INSTALL_WEB_SERVER}" == true ]]; then