#pragma once

// Minimal sd_listen_fds(3) reimplementation — one function, no libsystemd dependency, for
// the one fd velox.socket ever hands us. See velox.socket / velox.service in
// packaging/nativehost's systemd unit pair: the socket unit binds
// $XDG_RUNTIME_DIR/velox/velox.sock itself (before veloxd ever runs, so the very first
// connection attempt after boot is queued by the kernel rather than refused) and execs
// veloxd with that listening fd already open at fd 3, LISTEN_FDS=1, LISTEN_PID=<our pid>.

namespace velox::daemon::rpc {

// The systemd-activated listening socket fd, or -1 if this process was not socket-
// activated (LISTEN_PID doesn't match our pid, or LISTEN_FDS is unset/not exactly 1 — more
// than one would mean a unit file mismatch, since veloxd only ever asks for one socket).
// Clears LISTEN_PID/LISTEN_FDS from the environment on the way out either way, per
// sd_listen_fds's own contract, so a value meant for us is never mistaken for one meant for
// a process veloxd might itself exec later.
int systemd_activated_fd();

}  // namespace velox::daemon::rpc