standard cron

Signed-off-by: Eric Nemchik <eric@nemchik.com>

root/etc/s6-overlay/s6-rc.d/init-mod-universal-cron-add-package/run

@@ -1,9 +1,11 @@
 #!/usr/bin/with-contenv bash
 # shellcheck shell=bash
 
-if [ ! -f /usr/sbin/cron ] && [ -f /usr/bin/apt ]; then
+if ! builtin command -v busybox >/dev/null; then
+    echo "**** Adding busybox to package install list ****"
+    echo "busybox" >>/mod-repo-packages-to-install.list
+fi
+if [[ -f /usr/bin/apt ]] && [[ ! -f /usr/sbin/cron ]]; then
     echo "**** Adding cron to package install list ****"
     echo "cron" >>/mod-repo-packages-to-install.list
-else
-    echo "**** cron package already installed, skipping ****"
 fi

root/etc/s6-overlay/s6-rc.d/init-mod-universal-cron-setup/up

@@ -1 +0,0 @@
-/etc/s6-overlay/s6-rc.d/init-mod-universal-cron-setup/run

root/etc/s6-overlay/s6-rc.d/init-mod-universal-crontab-config/up

@@ -0,0 +1 @@
+/etc/s6-overlay/s6-rc.d/init-mod-universal-crontab-config/run

root/etc/s6-overlay/s6-rc.d/svc-cron/run

@@ -0,0 +1,10 @@
+#!/usr/bin/with-contenv bash
+# shellcheck shell=bash
+
+if builtin command -v busybox >/dev/null && [[ $(busybox) =~ [[:space:]](crond)([,]|$) ]]; then
+    exec busybox crond -f -S -l 5
+elif [[ -f /usr/bin/apt ]] && [[ -f /usr/sbin/cron ]]; then
+    exec /usr/sbin/cron -f -L 5
+else
+    echo "**** cron not found ****"
+fi

root/etc/s6-overlay/s6-rc.d/svc-mod-universal-cron/run

@@ -1,10 +0,0 @@
-#!/usr/bin/with-contenv bash
-# shellcheck shell=bash
-
-if [ -f /usr/bin/apt ]; then
-    # ubuntu
-    exec /usr/sbin/cron -f -L 1
-elif [ -f /sbin/apk ]; then
-    # alpine
-    exec /usr/sbin/crond -f -S -l 5
-fi