package/busybox: add crond init script

The init script will be installed only if no other package provides
cron (currently that could be package/dcron).

Our current default location for crontabs was the Busybox default of
/var/spool/cron/, but /var/spool is stored on tmpfs. This isn't
convenient as crontabs should normally be persistent, so we change
this default to /etc/cron, which is much more sensible. We also create
it to make sure to create this directory.

Signed-off-by: Fiona Klute <fiona.klute+wiwa@gmx.de>
[Thomas:
- Change default location of crontab
- Rework init script according to the latest coding style rules]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/busybox/S50crond

@@ -0,0 +1,60 @@
+#!/bin/sh
+
+DAEMON="crond"
+PIDFILE="/var/run/$DAEMON.pid"
+
+CROND_ARGS=""
+
+# shellcheck source=/dev/null
+[ -r "/etc/default/$DAEMON" ] && . "/etc/default/$DAEMON"
+
+# BusyBox' crond does not create a pidfile, so pass "-f" on the crond
+# command line and use "--make-pidfile" to instruct start-stop-daemon
+# to create one.
+start() {
+	printf 'Starting %s: ' "$DAEMON"
+	# shellcheck disable=SC2086 # we need the word splitting
+	start-stop-daemon --start --background --make-pidfile \
+		--pidfile "$PIDFILE" --exec "/usr/sbin/$DAEMON" \
+		-- -f $CROND_ARGS
+	status=$?
+	if [ "$status" -eq 0 ]; then
+		echo "OK"
+	else
+		echo "FAIL"
+	fi
+	return "$status"
+}
+
+stop() {
+	printf 'Stopping %s: ' "$DAEMON"
+	start-stop-daemon --stop --pidfile "$PIDFILE" --exec "/usr/sbin/$DAEMON"
+	status=$?
+	if [ "$status" -eq 0 ]; then
+		echo "OK"
+	else
+		echo "FAIL"
+	fi
+	while start-stop-daemon --stop --test --quiet --pidfile "$PIDFILE" \
+		--exec "/sbin/$DAEMON"; do
+		sleep 0.1
+	done
+	rm -f "$PIDFILE"
+	return "$status"
+}
+
+restart() {
+	stop
+	start
+}
+
+case "$1" in
+	start|stop|restart)
+		"$1";;
+	reload)
+		# Restart, since there is no true "reload" feature.
+		restart;;
+	*)
+		echo "Usage: $0 {start|stop|restart|reload}"
+		exit 1
+esac

package/busybox/busybox.config

@@ -782,7 +782,7 @@ CONFIG_CROND=y
 # CONFIG_FEATURE_CROND_D is not set
 # CONFIG_FEATURE_CROND_CALL_SENDMAIL is not set
 CONFIG_FEATURE_CROND_SPECIAL_TIMES=y
-CONFIG_FEATURE_CROND_DIR="/var/spool/cron"
+CONFIG_FEATURE_CROND_DIR="/etc/cron"
 CONFIG_CRONTAB=y
 # CONFIG_DEVFSD is not set
 # CONFIG_DEVFSD_MODLOAD is not set

package/busybox/busybox.mk

@@ -312,6 +312,18 @@ define BUSYBOX_INSTALL_SYSCTL_SCRIPT
 endef
 endif
 
+# Only install our crond script if no other package does it.
+ifeq ($(BR2_PACKAGE_DCRON),)
+define BUSYBOX_INSTALL_CROND_SCRIPT
+	if grep -q CONFIG_CROND=y $(@D)/.config; \
+	then \
+		mkdir -p $(TARGET_DIR)/etc/cron/crontabs ; \
+		$(INSTALL) -m 0755 -D package/busybox/S50crond \
+			$(TARGET_DIR)/etc/init.d/S50crond; \
+	fi;
+endef
+endif
+
 ifeq ($(BR2_INIT_BUSYBOX),y)
 define BUSYBOX_INSTALL_INITTAB
 	if test ! -e $(TARGET_DIR)/etc/inittab; then \
@@ -407,6 +419,7 @@ define BUSYBOX_INSTALL_INIT_OPENRC
 	$(BUSYBOX_INSTALL_MDEV_SCRIPT)
 	$(BUSYBOX_INSTALL_LOGGING_SCRIPT)
 	$(BUSYBOX_INSTALL_WATCHDOG_SCRIPT)
+	$(BUSYBOX_INSTALL_CROND_SCRIPT)
 	$(BUSYBOX_INSTALL_TELNET_SCRIPT)
 endef
 
@@ -419,6 +432,7 @@ define BUSYBOX_INSTALL_INIT_SYSV
 	$(BUSYBOX_INSTALL_LOGGING_SCRIPT)
 	$(BUSYBOX_INSTALL_WATCHDOG_SCRIPT)
 	$(BUSYBOX_INSTALL_SYSCTL_SCRIPT)
+	$(BUSYBOX_INSTALL_CROND_SCRIPT)
 	$(BUSYBOX_INSTALL_TELNET_SCRIPT)
 endef