[PATCH] fhandler_socket::recvmsg [WAS: Anyone interested in checkingout dgram socket problem (Conrad you still here?)]

[Thomas Pfaff]

On Tue, 5 Nov 2002, Christopher Faylor wrote:

> There is a thread in cygwin at cygwin entitled:
>
> "1.3.13-2 & 1.3.14-1 problem on read() from dgram socket"
>
> Is anyone willing to debug the problem and, if it is a cygwin problem,
> provide a fix?
>
> cgf
>
> http://cygwin.com/ml/cygwin/2002-10/msg01974.html
>

It seems that the fromlen in WSARecvFrom must be NULL if from is NULL and
not a pointer to 0.
Actually msg->msg_name is NULL and msg->msg_namelen is 0 which will result
in WSAEFAULT.

Thomas

2002-11-05  Thomas Pfaff  <[EMAIL PROTECTED]>

        * fhandler_socket.cc (fhandler_socket::recvmsg): If from == NULL
        call WSARecvFrom with fromlen = NULL.

--- fhandler_socket.cc.org      2002-10-21 03:03:32.000000000 +0200
+++ fhandler_socket.cc  2002-11-05 10:54:49.000000000 +0100
@@ -734,14 +734,16 @@ fhandler_socket::recvmsg (struct msghdr 
   struct iovec *const iov = msg->msg_iov;
   const int iovcnt = msg->msg_iovlen;
 
+  struct sockaddr *from = (struct sockaddr *) msg->msg_name;
+  int *fromlen = from ? &msg->msg_namelen : NULL;
+
   int res;
 
   if (!winsock2_active)
     {
       if (iovcnt == 1)
        res = recvfrom (iov->iov_base, iov->iov_len, flags,
-                       (struct sockaddr *) msg->msg_name,
-                       &msg->msg_namelen);
+                       from, fromlen);
       else
        {
          if (tot == -1)        // i.e. if not pre-calculated by the caller.
@@ -766,8 +768,7 @@ fhandler_socket::recvmsg (struct msghdr 
          else
            {
              res = recvfrom (buf, tot, flags,
-                             (struct sockaddr *) msg->msg_name,
-                             &msg->msg_namelen);
+                             from, fromlen);
 
              const struct iovec *iovptr = iov;
              int nbytes = res;
@@ -805,16 +806,14 @@ fhandler_socket::recvmsg (struct msghdr 
       if (is_nonblocking ())
        res = WSARecvFrom (get_socket (),
                           wsabuf, iovcnt, &ret, (DWORD *) &flags,
-                          (struct sockaddr *) msg->msg_name,
-                          &msg->msg_namelen,
+                          from, fromlen,
                           NULL, NULL);
       else
        {
          wsock_event wsock_evt;
          res = WSARecvFrom (get_socket (),
                             wsabuf, iovcnt, &ret, (DWORD *) &flags,
-                            (struct sockaddr *) msg->msg_name,
-                            &msg->msg_namelen,
+                            from, fromlen,
                             wsock_evt.prepare (), NULL);
 
          if (res == SOCKET_ERROR && WSAGetLastError () == WSA_IO_PENDING)