journald: fix ignored filtering patterns for delegated cgroups

If a service defines Delegate=yes, its subcgroup won't inherit the
LogFilterPatterns= option, because the option is stored on the unit's
cgroup attributes, not on the subcgroup.

Fixed by using the unit's cgroup attributes instead.

test/testsuite-04.units/delegated-cgroup-filtering.service

@@ -0,0 +1,8 @@
+[Unit]
+Description=Test service for delegated logs filtering
+
+[Service]
+Type=simple
+ExecStart=/usr/lib/systemd/tests/testdata/units/delegated_cgroup_filtering_payload.sh
+Delegate=yes
+SyslogLevel=notice

test/units/delegated_cgroup_filtering_payload.sh

@@ -0,0 +1,12 @@
+#!/bin/sh
+# SPDX-License-Identifier: LGPL-2.1-or-later
+
+mkdir /sys/fs/cgroup/system.slice/delegated-cgroup-filtering.service/the_child
+/bin/sh /usr/lib/systemd/tests/testdata/units/delegated_cgroup_filtering_payload_child.sh &
+
+while true
+do
+	echo "parent_process: hello, world!"
+	echo "parent_process: hello, people!"
+    sleep .15
+done

test/units/delegated_cgroup_filtering_payload_child.sh

@@ -0,0 +1,11 @@
+#!/bin/sh
+# SPDX-License-Identifier: LGPL-2.1-or-later
+
+echo $$ >/sys/fs/cgroup/system.slice/delegated-cgroup-filtering.service/the_child/cgroup.procs
+
+while true
+do
+	echo "child_process: hello, world!"
+	echo "child_process: hello, people!"
+    sleep .15
+done

test/units/testsuite-04.sh

@@ -185,8 +185,8 @@ function add_logs_filtering_override() {
     LOG_FILTER=${3:-""}
 
     mkdir -p /etc/systemd/system/"$UNIT".d/
-    echo "[Service]" >/etc/systemd/system/logs-filtering.service.d/"${OVERRIDE_NAME}".conf
-    echo "LogFilterPatterns=$LOG_FILTER" >>/etc/systemd/system/logs-filtering.service.d/"${OVERRIDE_NAME}".conf
+    echo "[Service]" >/etc/systemd/system/"$UNIT".d/"${OVERRIDE_NAME}".conf
+    echo "LogFilterPatterns=$LOG_FILTER" >>/etc/systemd/system/"$UNIT".d/"${OVERRIDE_NAME}".conf
     systemctl daemon-reload
 }
 
@@ -256,7 +256,14 @@ if is_xattr_supported; then
     add_logs_filtering_override "logs-filtering.service" "10-allow-with-escape-char" "\x7emore~"
     [[ -n $(run_service_and_fetch_logs "logs-filtering.service") ]]
 
+    add_logs_filtering_override "delegated-cgroup-filtering.service" "00-allow-all" ".*"
+    [[ -n $(run_service_and_fetch_logs "delegated-cgroup-filtering.service") ]]
+
+    add_logs_filtering_override "delegated-cgroup-filtering.service" "01-discard-hello" "~hello"
+    [[ -z $(run_service_and_fetch_logs "delegated-cgroup-filtering.service") ]]
+
     rm -rf /etc/systemd/system/logs-filtering.service.d
+    rm -rf /etc/systemd/system/delegated-cgroup-filtering.service.d
 fi
 
 touch /testok