Ensure EBADF returns for socket functions on mingw.

* lib/accept.c (rpl_accept): Fail with error EBADF if the file
descriptor is invalid.
* lib/bind.c (rpl_bind): Likewise.
* lib/connect.c (rpl_connect): Likewise.
* lib/getpeername.c (rpl_getpeername): Likewise.
* lib/getsockname.c (rpl_getsockname): Likewise.
* lib/getsockopt.c (rpl_getsockopt): Likewise.
* lib/listen.c (rpl_listen): Likewise.
* lib/recv.c (rpl_recv): Likewise.
* lib/recvfrom.c (rpl_recvfrom): Likewise.
* lib/send.c (rpl_send): Likewise.
* lib/sendto.c (rpl_sendto): Likewise.
* lib/setsockopt.c (rpl_setsockopt): Likewise.
* lib/shutdown.c (rpl_shutdown): Likewise.

1 files changed, 13 insertions, 4 deletions

diff --git a/lib/sendto.c b/lib/sendto.c
index e301626dfb..95efab8885 100644
--- a/lib/sendto.c
+++ b/lib/sendto.c
@@ -33,9 +33,18 @@ rpl_sendto (int fd, const void *buf, size_t len, int flags,
             const struct sockaddr *to, socklen_t tolen)
 {
   SOCKET sock = FD_TO_SOCKET (fd);
-  int r = sendto (sock, buf, len, flags, to, tolen);
-  if (r < 0)
-    set_winsock_errno ();
 
-  return r;
+  if (sock == INVALID_SOCKET)
+    {
+      errno = EBADF;
+      return -1;
+    }
+  else
+    {
+      int r = sendto (sock, buf, len, flags, to, tolen);
+      if (r < 0)
+        set_winsock_errno ();
+
+      return r;
+    }
 }