+ /* At-least-once ensures that expiries are still checked on timeouts. */
+ do {
+ for (Fifo *f = cfg->fifos; f; f = f->next) {
+ if (FD_ISSET(f->fd, &fds)) {
+ debug("reading: %s\n", f->name);
+ switch (fifo_read_one(f, t, buf)) {
+ /*
+ * ### MESSAGE LOSS ###
+ * is introduced by closing at EOM in addition
+ * to EOF, since there may be unread messages
+ * remaining in the pipe. However,
+ *
+ * ### INTER-MESSAGE PUSHBACK ###
+ * is also gained, since pipes block at the
+ * "open" call.
+ *
+ * This is an acceptable trade-off because we
+ * are a stateless reporter of a _most-recent_
+ * status, not a stateful accumulator.
+ */
+ case END_OF_MESSAGE:
+ case END_OF_FILE:
+ case FAILURE:
+ close(f->fd);
+ f->fd = -1;
+ ready--;
+ break;
+ case RETRY:
+ break;
+ default:
+ assert(0);
+ }
+ } else {
+ fifo_expire(f, t, buf);
+ }
+ }
+ } while (ready);
+ assert(ready == 0);