How should yrmcds behave when FDs are depleted?

[nojima]

Once FDs are depleted, yrmcds crashes because of cybozu::has_ip_address.

2024-07-24 09:36:27 ERROR [std::system_error] (system:24) getifaddrs: Too many open files

I am not sure if this behavior is a problem or not. One could argue that abnormal termination upon FD exhaustion is inevitable. On the other hand, it is another idea that it should work even during FD exhaustion (even if it cannot accept new connections) and that all functions should recover once the FD exhaustion is resolved.