fix(udp): receive(0) tests and bad call to getnameinfo

1 files changed, 8 insertions, 0 deletions

diff --git a/src/wsocket.c b/src/wsocket.c
index 86c6994..b2b668c 100644
--- a/src/wsocket.c
+++ b/src/wsocket.c
@@ -286,6 +286,14 @@ int socket_recvfrom(p_socket ps, char *data, size_t count, size_t *got,
         }
         if (taken == 0) return IO_CLOSED;
         err = WSAGetLastError();
+        /* a zero-length request is trivially "too small" for any
+         * non-empty datagram; unlike POSIX, which truncates and succeeds
+         * silently, Windows reports this as WSAEMSGSIZE even though the
+         * datagram -- and its sender's address, already written to addr/
+         * len above -- was still consumed. Normalize it to match POSIX's
+         * silent-truncation instead of surfacing a platform-specific
+         * error for what is otherwise a successful, if empty, receive. */
+        if (count == 0 && err == WSAEMSGSIZE) return IO_DONE;
         /* On UDP, a connreset simply means the previous send failed.
          * So we try again.
          * On TCP, it means our socket is now useless, so the error passes.