supervision as supervisord does it: Postfix stopped, give-ups FATAL, reload's exit read

C-P42. postfix-script's start-fg runs master as its child and master
calls setsid() (Postfix 3.7.11, conf/postfix-script; src/master/master.c);
supervisord signals the pid alone (supervisor 4.2.5, process.py,
Subprocess.kill()). A stop of program postfix left master running - a
restart then found "already running" - and a container stop cut Postfix
off with SIGKILL. The wrapper now stays the parent of "postfix start-fg"
and on TERM/INT runs "postfix stop", asking again while start-fg is still
in its checks (master -t). stopwaitsecs=15.

C-V6. The wrapper's give-up on the milter sockets came after the default
startsecs, so it was EXITED and restarted for ever. startsecs is now
MILTER_WAIT_TIMEOUT + 10, exported by the entrypoint as POSTFIX_STARTSECS
and expanded by supervisord (options.py, processes_from_section(); a
non-number MILTER_WAIT_TIMEOUT stops the start): a give-up is "Exited too
quickly", BACKOFF, FATAL after startretries, crashexit. For those seconds
after each start the program is STARTING (the healthcheck's 90 s start
period covers it; the sender check counts no downtime then).

C-V5. logrotate had startsecs=0, so a refused config restarted it every
second for ever. startsecs=1: FATAL after startretries; crashexit reads
the event's processname and leaves logrotate's FATAL on Server > Health.

B-U2. "supervisorctl start" returns when a startsecs=0 program is RUNNING,
not when it ends, and mapped "already started" to success. The panel now
speaks supervisord's XML-RPC itself (internal/supervisor, RunOnce):
startProcess without waiting, getProcessInfo until it leaves
STARTING/RUNNING, exitstatus 0 or an error; a run in progress is waited
out and one of its own follows. A failed reload while program postfix is
not RUNNING is logged, not an error: the next master reads the files.
C-V10: postfix-reload rests EXITED after a run; the e2e process check
takes STOPPED or EXITED. C-P34: the dead "postfix set-permissions" branch
goes - postfix check's create-missing builds the queue tree.

Stand (2026-10-14, make e2e, exit 0; MILTER_WAIT_TIMEOUT=10 on the stand):
new supervision_stops_postfix_and_gives_up - supervisorctl restart postfix
writes postfix-script's "stopping the Postfix mail system" and leaves one
master; with the panel's sockets removed, start answers "postfix: ERROR
(spawn error)" (finish() sets spawnerr "Exited too quickly", onwait()
reads it first) and Postfix comes up once the panel is back; a
group-writable logrotate config ends FATAL with the container up; the
panel's Reload configuration answers only after mail.log has "refreshing
the Postfix mail system", postfix-reload EXITED. session_survives_restart
sees the stop line for the container's restart. Measured: master's own
"terminating on signal 15" never reaches mail.log (master TERMs its group,
postlogd included, before it logs). go vet and go test ./... pass on the
server (24 packages; new unit tests of RunOnce against a fake supervisord).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

cmd/panel/sendercheck.go

@@ -139,7 +139,10 @@ var postfixAskFor, postfixAskEvery = 30 * time.Second, 2 * time.Second
 // the spawn of program "postfix", which is build/postfix-wrapper.sh; it waits
 // for the milter sockets (up to MILTER_WAIT_TIMEOUT) before it execs
 // "postfix start-fg", so the time given is up to that much early
-// (assumptions A-46).
+// (assumptions A-46). For startsecs - that wait plus ten seconds
+// (build/supervisord.conf) - after its start the program is STARTING, not
+// RUNNING, and is taken here as not running: a panel restart within that
+// time after Postfix's own counts no downtime.
 func postfixStarted() postfixState {
 	deadline := time.Now().Add(postfixAskFor)
 	for {