pub fn daemon_singleton_holder() -> Option<u32>Expand description
Inspect the daemon singleton state. Returns Some(pid) iff the
pidfile names a live wire daemon process — i.e., a singleton is
currently held by another in-flight daemon. Returns None if the
pidfile is missing, corrupt, or names a dead process.
v0.14.2 (#162): foreground wire daemon (the operator-typed kind,
not the ensure_background spawn path) didn’t write its own
pidfile, so subsequent ensure_daemon_running() calls couldn’t
see it and would spawn duplicates. The duplicate-pull race is
safe — per-path outbox locks prevent corruption — but it wastes
relay polls and confuses operator diagnosis (“why are there 3
daemons?”). The singleton helpers below let cmd_daemon claim
the slot at startup + write its own pidfile, closing the gap.