Use systemd for start and stop of zram-config (#78)

This implements properly working support for systemd start and stop
functions. Proper integration with systemd means that there is no longer
a need to use hacky workarounds when the user wants to stop zram-config
manually.

Signed-off-by: Ethan Dye <[email protected]>

README.md

@@ -32,6 +32,7 @@ See [raspberrypi/linux@cef3970381](https://github.com/raspberrypi/linux/commit/c
 ### Table of Contents
 
 1.  [Install](#install)
+    -   [Manually start or stop](#manually-start-or-stop)
 2.  [Update](#update)
 3.  [Uninstall](#uninstall)
 4.  [Configure](#customize)
@@ -53,17 +54,10 @@ git clone https://github.com/ecdye/zram-config
 sudo ./zram-config/install.bash
 ```
 
-Note: The recommended way to stop the `zram-config.service` is to run
-``` shell
-sudo zram-config "stop"
-```
-**NOT**
-``` shell
-sudo systemctl stop zram-config.service
-```
-because of issues with the way systemd works with zram logging.
+#### Manually start or stop
 
-The service will stop normally on reboot, there is no need to manually stop it.
+Use `sudo systemctl {start|stop} zram-config.service` to start or stop zram-config.
+This will ensure that any changes are properly synced to the persistent storage before system poweroff.
 
 ### Update
 
@@ -108,7 +102,7 @@ Usually in `/opt` or `/var`, name optional.
 Usually in `/opt` or `/var`, name optional.
 
 If you need multiple zram swaps or zram directories, just create another entry in `/etc/ztab`.
-To do this simply add the new entries to the `/etc/ztab`, if you need to edit an active zram device you must stop zram with `sudo zram-config "stop"` and then edit any entries you need to.
+To do this simply add the new entries to the `/etc/ztab`, if you need to edit an active zram device you must stop zram with `sudo systemctl stop zram-config.service` and then edit any entries you need to.
 Once finished, start zram using `sudo systemctl start zram-config.service` which will only add the new entries if zram is already running.
 
 #### Example configuration

install.bash

@@ -31,7 +31,6 @@ make --always-make --directory="${BASEDIR}/overlayfs-tools"
 echo "Installing zram-config files"
 install -m 755 "${BASEDIR}/zram-config" /usr/local/sbin/
 install -m 644 "${BASEDIR}/zram-config.service" /etc/systemd/system/zram-config.service
-install -m 644 "${BASEDIR}/zram-config-shutdown.service" /etc/systemd/system/zram-config-shutdown.service
 install -m 644 "${BASEDIR}/ztab" /etc/ztab
 mkdir -p /usr/local/share/zram-config/log
 ln -s /usr/local/share/zram-config/log /var/log/zram-config
@@ -43,8 +42,8 @@ echo "ReadWritePaths=/usr/local/share/zram-config/log" >> /lib/systemd/system/lo
 
 echo "Starting zram-config.service"
 systemctl daemon-reload
-systemctl enable --now zram-config.service zram-config-shutdown.service
-until [[ $(systemctl show -p SubState --value zram-config) == "dead" ]]; do
+systemctl enable --now zram-config.service
+until [[ $(systemctl show -p SubState --value zram-config) == "exited" ]]; do
   sleep 5
 done
 

tests/image.bash

@@ -23,9 +23,9 @@ if [[ $1 == "setup" ]]; then
     gpg -q --keyserver keyserver.ubuntu.com --recv-key 0x8738CD6B956F460C
     gpg -q --trust-model always --verify "${2}.sig" "$2"
     unzip -q "$2" -d .
-    qemu-img resize -f raw "$3" 4G
-    echo ", +" | sfdisk -N 2 "$3"
   fi
+  qemu-img resize -f raw "$3" 4G
+  echo ", +" | sfdisk -N 2 "$3"
   mountImageFile "mount" "$3"
   rsync -avr --exclude="*.zip" --exclude="*.img" --exclude="*.sig" --exclude="tests/fs" --exclude="tests/dtb" --exclude="tests/kernel" ./ tests/fs/opt/zram
   systemd-nspawn --directory="tests/fs" /opt/zram/tests/install-packages.bash

uninstall.bash

@@ -13,8 +13,8 @@ fi
 
 zram-config "stop"
 tar -cf "${BASEDIR}/logs.tar" --directory=/usr/local/share/zram-config log
-systemctl disable zram-config.service zram-config-shutdown.service
-rm -f /etc/systemd/system/zram-config.service /etc/systemd/system/zram-config-shutdown.service
+systemctl disable zram-config.service
+rm -f /etc/systemd/system/zram-config.service
 sed -i '\|^ReadWritePaths=/usr/local/share/zram-config/log$|d' /lib/systemd/system/logrotate.service
 systemctl daemon-reload
 rm -f /usr/local/sbin/zram-config

update.bash

@@ -36,7 +36,6 @@ zram-config "stop"
 echo "Updating zram-config files"
 install -m 755 "${BASEDIR}/zram-config" /usr/local/sbin/
 install -m 644 "${BASEDIR}/zram-config.service" /etc/systemd/system/zram-config.service
-install -m 644 "${BASEDIR}/zram-config-shutdown.service" /etc/systemd/system/zram-config-shutdown.service
 install -m 755 "${BASEDIR}/uninstall.bash" /usr/local/share/zram-config/uninstall.bash
 if ! [[ -f /etc/ztab ]]; then
   install -m 644 "${BASEDIR}/ztab" /etc/ztab
@@ -60,7 +59,7 @@ fi
 
 echo "Starting zram-config.service"
 systemctl daemon-reload
-systemctl enable --now zram-config.service zram-config-shutdown.service
+systemctl enable --now zram-config.service
 
 echo "#####        zram-config has been updated         #####"
 echo "#####     edit /etc/ztab to configure options     #####"

zram-config

@@ -141,10 +141,12 @@ removeZdir() {
 	fi
 	rm -rfv "${ZDIR}${BIND_DIR}" >> "$ZLOG" 2>&1 || return 1
 
-	until zramctl --reset "/dev${ZRAM_DEV}" >> "$ZLOG" 2>&1 || [[ count -ge 5 ]]; do
-		count=$(( count + 1 ))
-		sleep 5
-  done
+	if [[ -z $SERVICE ]]; then  # We don't care about device reset when shutting down system
+		until zramctl --reset "/dev${ZRAM_DEV}" >> "$ZLOG" 2>&1 || [[ count -ge 5 ]]; do
+			count=$(( count + 1 ))
+			sleep 5
+		done
+	fi
 
 	echo "removeZdir: Device /dev$ZRAM_DEV removed." >> "$ZLOG"
 }
@@ -163,20 +165,20 @@ serviceConfiguration() {
 		echo "Stopping services that interfere with zram device configuration." >> "$ZLOG"
 		if [[ $(systemctl is-active rsyslog.service) == "active" ]]; then
 			export rsyslogActive="true"
-			systemctl stop syslog.socket >> "$ZLOG" 2>&1 || return 1
+			systemctl --no-block stop syslog.socket >> "$ZLOG" 2>&1 || return 1
 		fi
 		if [[ $(systemctl is-active systemd-journald.service) == "active" ]]; then
 			export journaldActive="true"
 			journalctl --flush >> "$ZLOG" 2>&1 || return 1
-			systemctl stop systemd-journald.socket systemd-journald-audit.socket systemd-journald-dev-log.socket >> "$ZLOG" 2>&1 || return 1
+			systemctl --no-block stop systemd-journald.socket systemd-journald-audit.socket systemd-journald-dev-log.socket >> "$ZLOG" 2>&1 || return 1
 		fi
 	elif [[ $1 == "start" ]]; then
 		echo "Restarting services that interfere with zram device configuration." >> "$ZLOG"
 		if [[ -n $journaldActive ]]; then
-			systemctl restart systemd-journald.socket systemd-journald-audit.socket systemd-journald-dev-log.socket >> "$ZLOG" 2>&1 || return 1
+			systemctl --no-block restart systemd-journald.socket systemd-journald-audit.socket systemd-journald-dev-log.socket >> "$ZLOG" 2>&1 || return 1
 		fi
 		if [[ -n $rsyslogActive ]]; then
-			systemctl restart syslog.socket >> "$ZLOG" 2>&1 || return 1
+			systemctl --no-block restart syslog.socket >> "$ZLOG" 2>&1 || return 1
 		fi
 	fi
 }
@@ -185,8 +187,8 @@ TMPDIR="/tmp"
 ZDIR="/opt/zram"
 ZSHARE="/usr/local/share/zram-config"
 ZLOG="${ZSHARE}/log/zram-config.log"
-if [[ $2 == "shutdown" ]]; then
-  SERVICE="1"
+if [[ -f /run/systemd/shutdown/scheduled ]]; then
+	SERVICE="1"
 fi
 
 case "$1" in

zram-config.service

@@ -1,13 +1,16 @@
 [Unit]
 Description=zram-config
 Documentation=https://github.com/ecdye/zram-config/blob/main/README.md
+Requires=local-fs.target
 After=local-fs.target
-Before=zram-config-shutdown.service
 
 [Service]
 Type=exec
-TimeoutSec=300
+TimeoutSec=120
+RemainAfterExit=yes
 ExecStart=/usr/local/sbin/zram-config "start"
+ExecReload=/usr/local/sbin/zram-config "start"
+ExecStop=/usr/local/sbin/zram-config "stop"
 
 [Install]
-WantedBy=basic.target
+WantedBy=multi-user.target

ztab

@@ -36,9 +36,9 @@
 # If you need multiple zram swaps or zram directories, just create another entry
 # in this file. To do this simply add the new entries to this file, if you need
 # to edit an active zram device you must stop zram with
-# 'sudo zram-config "stop"' and then edit any entries you need to. Once
-# finished, start zram using 'sudo systemctl start zram-config.service' which
-# will only add the new entries if zram is already running.
+# 'sudo systemctl stop zram-config.service' and then edit any entries you need
+# to. Once finished, start zram using 'sudo systemctl start zram-config.service'
+# which will only add the new entries if zram is already running.
 
 # swap	alg		mem_limit	disk_size	swap_priority	page-cluster	swappiness
 swap	lzo-rle		250M		750M		75		0		150