Fix a whole in the logic from the previous check-in

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@5718 42af7a65-404d-4744-a932-0658087f49c3

ChangeLog

@@ -4262,3 +4262,22 @@
 	* arch/arm: Correct some bad syscall dispatching logic.  This change
 	  cannot be fully tested until there is a fielded NuttX kernel build.
 	  (2013-03-06).
+	* net/net_poll.c:  Correct logic that checks if the socket is
+	  disconnected when the poll is setup.  That is bad logic:  Listen
+	  sockets, for example, are not connected.  In that case, the purpose of
+	  the poll is to wait for connection events.  As a result of this,
+	  poll/select would return immediately with POLLHUP with it was used to
+	  detect connection events.  This fix for now was to check instead if
+	  the socket is closed (meaning that it was connected at one time but
+	  was closed by the remote peer).  That excludes the listen socket which
+	  was never connected.  This does introduce a new problem, however.  If
+	  the socket was not closed, but lost the connection through an abnormal
+	  event, then poll/select will hang.  That needs to be revisited.\
+	  (2013-03-07)
+	* fs/fs_selected.c:  Was not checking if the timeout parameter was NULL
+	  but would, instead, setup a bogus timeout based on whatever it found at
+	  address zero.  Also, improved some of the memory allocation logic so
+	  that it will not use so much memory. (2013-03-07)
+	* net/net_poll.c:  Handle the missing case.  Now tests for not connected
+	  AND not listening.  I think that now covers all of the cases including
+	  the missing case noted above. (2013-03-07)

include/nuttx/net/net.h

@@ -97,7 +97,7 @@ struct socket
   socktimeo_t   s_sndtimeo;  /* Send timeout value (in deciseconds) */
 #endif
 #endif
-  void         *s_conn;      /* Connection: struct uip_conn or uip_udp_conn */
+  FAR void     *s_conn;      /* Connection: struct uip_conn or uip_udp_conn */
 };
 
 /* This defines a list of sockets indexed by the socket descriptor */

net/net_poll.c

@@ -258,20 +258,48 @@ static inline int net_pollsetup(FAR struct socket *psock,
    *
    * 1) The socket is connected and we are waiting for data availability
    *    events.
+   *
+   *    __SS_ISCONNECTED(f) == true
+   *    __SS_ISLISTENING(f) == false
+   *    __SS_ISCLOSED(f)    == false
+   *
+   *    Action: Wait for data availability events
+   *
    * 2) This is a listener socket that was never connected and we are
    *    waiting for connection events.
+   *
+   *    __SS_ISCONNECTED(f) == false
+   *    __SS_ISLISTENING(f) == true
+   *    __SS_ISCLOSED(f)    == false
+   *
+   *    Action: Wait for connection events
+   *
    * 3) This socket was previously connected, but the peer has gracefully
    *    closed the connection.
+   *
+   *    __SS_ISCONNECTED(f) == false
+   *    __SS_ISLISTENING(f) == false
+   *    __SS_ISCLOSED(f)    == true
+   *
+   *    Action: Return with POLLHUP|POLLERR events
+   *
    * 4) This socket was previously connected, but we lost the connection
    *    due to some exceptional event.
    *
-   * We can detect 1) and 3), but 2) and 4) appear the same.  So we
-   * do the best we can for now:  We will report POLLHUP if the socket
-   * has been gracefully closed.
+   *    __SS_ISCONNECTED(f) == false
+   *    __SS_ISLISTENING(f) == false
+   *    __SS_ISCLOSED(f)    == false
+   *
+   *    Action: Return with POLLHUP|POLLERR events
    */
 
-  if (_SS_ISCLOSED(psock->s_flags))
+  if (!_SS_ISCONNECTED(psock->s_flags) && !_SS_ISLISTENING(psock->s_flags))
     {
+      /* We were previously connected but lost the connection either due
+       * to a graceful shutdown by the remote peer or because of some
+       * exceptional event.
+       */
+
       fds->revents |= (POLLERR | POLLHUP);
     }