CNSocket::kill() will now no longer call close() on already closed sockets.
close() should never be called on already closed file descriptors, yet
CNSocket::kill() was lacking any protection against that, despite its
use as both a high-level way of killing player connections and as a
means of ensuring that closing connections have been properly terminated
in the poll() loop.
This was causing close() to be erroneously called on each socket at least
one extra time. It was also introducing a race condition where the login
and shard threads could close each other's newly opened sockets due to
file descriptor reuse when a connection was accept()ed after the first
call to close(), but before the second one. See the close(2) manpage for
details.
Previously, terminating a running server from the terminal would
sometimes print a benign warning message if the server was currently
handling an incoming packet. This happened because CNServer::step()
would continue handling the packet after CNServer::kill() released the
activeCrit mutex. Now it first re-checks if active has been set to false
in the mean time after acquiring the mutex.
This change subtly broke the poll() loop when a connection was removed,
because erasing an entry from fds would invalidate the iterator that
was still being used.
This reverts commit ec67cc6527.
CNProtocol, CNShared, CNStructs and Defines are now in core/.
CNLoginServer, CNShardServer and Monitor are now in servers/.
core/Core.hpp wraps all the core headers except for CNShared.hpp.
Defines.cpp has been renamed to Packets.cpp, and so has its
corresponding namespace, but not the header file. This is in preparation
for upcoming changes.
