ci: add test for poll limit

test/TEST-07-PID1/test.sh

@@ -32,6 +32,8 @@ Alias=issue2730-alias.mount
 EOF
     "${SYSTEMCTL:?}" enable --root="$workspace" issue2730.mount
     ln -svrf "$workspace/etc/systemd/system/issue2730.mount" "$workspace/etc/systemd/system/issue2730-alias.mount"
+
+    image_install logger
 }
 
 do_test "$@"

test/units/testsuite-07.poll-limit.sh

@@ -0,0 +1,48 @@
+#!/usr/bin/env bash
+# SPDX-License-Identifier: LGPL-2.1-or-later
+set -eux
+set -o pipefail
+
+systemd-analyze log-level debug
+
+cat > /run/systemd/system/floodme@.service <<EOF
+[Service]
+ExecStart=/bin/true
+EOF
+
+cat > /run/systemd/system/floodme.socket <<EOF
+[Socket]
+ListenStream=/tmp/floodme
+PollLimitIntervalSec=10s
+Accept=yes
+PollLimitBurst=3
+EOF
+
+systemctl daemon-reload
+systemctl start floodme.socket
+
+START=$(date +%s%N)
+
+# Trigger this 100 times in a flood
+for (( i=0 ; i < 100; i++ )) ; do
+    logger -u /tmp/floodme foo &
+done
+
+# Let some time pass
+sleep 5
+
+END=$(date +%s%N)
+
+PASSED=$((END-START))
+
+# Calculate (round up) how many trigger events could have happened in the passed time
+MAXCOUNT=$(((PASSED+10000000000)*3/10000000000))
+
+# We started 100 connection attempts, but only 3 should have gone through, as per limit
+test "$(systemctl show -P NAccepted floodme.socket)" -le "$MAXCOUNT"
+
+systemctl stop floodme.socket floodme@*.service
+
+rm /run/systemd/system/floodme@.service /run/systemd/system/floodme.socket /tmp/floodme
+
+systemctl daemon-reload