Merge pull request #9625 from rooklz/fix/macos-shutdown-already-shut

fix(libkernel): treat a socket direction that is already shut as shut on macOS hosts

core/libs/prx/libkernel/Socket/src/Udp.cpp

@@ -1377,11 +1377,30 @@ int APS5_VABI bind_nid_postfix(int descriptor, const void* address, std::uint32_
     if (!Address(socket->family, address, mapped ? 28 : length, native, size)) return -1;
     return ::bind(socket->value, reinterpret_cast<sockaddr*>(&native), size) ? Fail(NativeError()) : 0;
 }
+namespace {
+bool AlreadyShut(NativeSocket socket, int how) {
+#ifdef __APPLE__
+    if (errno != ENOTCONN) return false;
+    sockaddr_storage peer{};
+    socklen_t size = sizeof(peer);
+    if (::getpeername(socket, reinterpret_cast<sockaddr*>(&peer), &size)) {
+        errno = ENOTCONN;
+        return false;
+    }
+    return how != SHUT_RDWR || ::shutdown(socket, SHUT_WR) == 0 || errno == ENOTCONN;
+#else
+    (void)socket;
+    (void)how;
+    return false;
+#endif
+}
+}
+
 int APS5_VABI shutdown_nid_postfix(int descriptor, int how) {
     const auto socket = Lookup(descriptor);
     if (!socket) return -1;
     if (how < 0 || how > 2) return Fail(22);
-    if (::shutdown(socket->value, how)) return Fail(NativeError());
+    if (::shutdown(socket->value, how) && !AlreadyShut(socket->value, how)) return Fail(NativeError());
     std::lock_guard lock(socket->modeMutex);
     if (how != 1) socket->receiveShut = true;
     if (how != 0) socket->sendShut = true;