service: keep a pending reload across a second conf reload

A service whose condition goes into flux during a reload is paused
with its reload still pending.  If another reload was requested in
the meantime, re-parsing its unchanged .conf file cleared the pending
mark, so the service was resumed without ever being reloaded.  Seen
with sshd <pid/syslogd> on Infix, where a configuration change that
touched both landed as two reloads in a row and sshd kept its old
listen addresses.

The mark is only ever cleared once the change has been applied, so a
mark that is still set when the file is parsed again means exactly
that: not applied yet.  Leave it alone.

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

test/Makefile.am

@@ -43,6 +43,7 @@ EXTRA_DIST		+= conf-template.sh
 EXTRA_DIST		+= script-timeout.sh
 EXTRA_DIST		+= crashing.sh
 EXTRA_DIST		+= dep-chain-reload.sh
+EXTRA_DIST		+= reload-while-paused.sh
 EXTRA_DIST		+= depserv.sh
 EXTRA_DIST		+= devmon.sh
 EXTRA_DIST		+= failing-sysv.sh
@@ -109,6 +110,7 @@ TESTS			+= conf-template.sh
 TESTS			+= script-timeout.sh
 TESTS			+= crashing.sh
 TESTS			+= dep-chain-reload.sh
+TESTS			+= reload-while-paused.sh
 TESTS			+= depserv.sh
 TESTS			+= devmon.sh
 TESTS			+= failing-sysv.sh

test/reload-while-paused.sh

@@ -0,0 +1,76 @@
+#!/bin/sh
+# A reload must not be lost on a service paused by a condition
+#
+# svc_s writes its PID file one second after a SIGHUP, so a service
+# with <pid/svc_s> is paused for that second whenever svc_s reloads.
+# svc_x counts the SIGHUPs it gets.  Both .conf files are touched and
+# two reloads are requested back to back, so the second one arrives
+# while svc_x is paused with its own reload still pending.  svc_x must
+# get exactly one SIGHUP and keep its PID.
+
+set -eu
+
+TEST_DIR=$(dirname "$0")
+
+test_teardown()
+{
+    say "Running test teardown."
+    run "rm -f $FINIT_RCSD/svc_s.conf $FINIT_RCSD/svc_x.conf /tmp/hup.sh /tmp/hup.log"
+}
+
+pidof()
+{
+    texec initctl -j status "$1" | jq .pid
+}
+
+test_setup()
+{
+    run "cat > /tmp/hup.sh" <<EOF
+#!/bin/sh
+trap 'echo HUP >> /tmp/hup.log' HUP
+trap 'exit 0' TERM
+while true; do
+    sleep 1
+done
+EOF
+    run "cat > $FINIT_RCSD/svc_s.conf" <<EOF
+service log:stdout notify:pid pid:!/run/service.pid name:svc_s service.sh -- Slow to reassert
+EOF
+    run "cat > $FINIT_RCSD/svc_x.conf" <<EOF
+service log:stdout <pid/svc_s> name:svc_x /bin/sh /tmp/hup.sh -- Paused while svc_s reloads
+EOF
+}
+
+# shellcheck source=/dev/null
+. "$TEST_DIR/lib/setup.sh"
+
+sep "Configuration"
+run "cat $FINIT_RCSD/svc_s.conf"
+run "cat $FINIT_RCSD/svc_x.conf"
+
+say "Reload Finit to start both services"
+run "initctl reload"
+retry 'assert_status "svc_x" "running"' 10 1
+
+pid_x=$(pidof svc_x)
+say "svc_x PID before: $pid_x"
+
+sep "Touch both, reload twice"
+run "rm -f /tmp/hup.log"
+run "initctl touch svc_s.conf"
+run "initctl touch svc_x.conf"
+run "initctl reload"
+run "initctl reload"
+
+say "Wait for services to settle"
+retry 'assert_status "svc_x" "running"' 15 1
+run "initctl status"
+
+# shellcheck disable=SC2016
+retry 'assert "svc_x got its SIGHUP" "$(texec sh -c "cat /tmp/hup.log 2>/dev/null | wc -l")" -eq 1' 10 1
+
+new_pid_x=$(pidof svc_x)
+# shellcheck disable=SC2086
+assert "svc_x was not restarted" $new_pid_x -eq $pid_x
+
+return 0