From 95012189c0fb4776f1c50ef66a3b360b42f6c03b Mon Sep 17 00:00:00 2001
From: Ken Brown <kbrown@cornell.edu>
Date: Fri, 16 Oct 2020 17:54:23 -0400
Subject: [PATCH] Cygwin: AF_UNIX: sendmsg: fix errno if socket is shut down

Following Posix and Linux, the errno should be EPIPE, not ESHUTDOWN.
---
 winsup/cygwin/fhandler_socket_unix.cc | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/winsup/cygwin/fhandler_socket_unix.cc b/winsup/cygwin/fhandler_socket_unix.cc
index ed96bbe27..11a3623e3 100644
--- a/winsup/cygwin/fhandler_socket_unix.cc
+++ b/winsup/cygwin/fhandler_socket_unix.cc
@@ -2493,7 +2493,11 @@ fhandler_socket_unix::sendmsg (const struct msghdr *msg, int flags)
 	    }
 	  if (saw_shutdown () & _SHUT_SEND)
 	    {
-	      set_errno (ESHUTDOWN);
+	      set_errno (EPIPE);
+	      /* FIXME: Linux calls for SIGPIPE here, but Posix
+		 doesn't.  Should we follow Linux? */
+	      if (!(flags & MSG_NOSIGNAL))
+		raise (SIGPIPE);
 	      __leave;
 	    }
 	}