Added except set support in select (patch #6860)

CHANGELOG

@@ -19,6 +19,10 @@ HISTORY
 
   ++ New features:
 
+  2010-01-29: Simon Goldschmidt (patch by Laura Garrett)
+  * api.h, api_msg.c, sockets.c: Added except set support in select
+    (patch #6860)
+
   2010-01-29: Simon Goldschmidt (patch by Laura Garrett)
   * api.h, sockets.h, err.h, api_lib.c, api_msg.c, sockets.c, err.c:
     Add non-blocking support for connect (partly from patch #6860),

src/api/api_msg.c

@@ -330,7 +330,7 @@ err_tcp(void *arg, err_t err)
 
   conn->pcb.tcp = NULL;
 
-  /* no check since this is always fatal */
+  /* no check since this is always fatal! */
   SYS_ARCH_PROTECT(lev);
   conn->last_err = err;
   SYS_ARCH_UNPROTECT(lev);
@@ -339,18 +339,25 @@ err_tcp(void *arg, err_t err)
   old_state = conn->state;
   conn->state = NETCONN_NONE;
 
+  /* Notify the user layer about a connection error. Used to signal
+     select. */
+  API_EVENT(conn, NETCONN_EVT_ERROR, 0);
+  /* Try to release selects pending on 'read' or 'write', too.
+     They will get an error if they actually try to read or write. */
+  API_EVENT(conn, NETCONN_EVT_RCVPLUS, 0);
+  API_EVENT(conn, NETCONN_EVT_SENDPLUS, 0);
+
+  /* pass NULL-message to recvmbox to wake up pending recv */
   if (conn->recvmbox != SYS_MBOX_NULL) {
-    /* Register event with callback */
-    API_EVENT(conn, NETCONN_EVT_RCVPLUS, 0);
-    /* use trypot to preven deadlock */
+    /* use trypost to prevent deadlock */
     sys_mbox_trypost(conn->recvmbox, NULL);
   }
+  /* pass NULL-message to acceptmbox to wake up pending accept */
   if (conn->acceptmbox != SYS_MBOX_NULL) {
-    /* Register event with callback */
-    API_EVENT(conn, NETCONN_EVT_RCVPLUS, 0);
-    /* use trypot to preven deadlock */
+    /* use trypost to preven deadlock */
     sys_mbox_trypost(conn->acceptmbox, NULL);
   }
+
   if ((old_state == NETCONN_WRITE) || (old_state == NETCONN_CLOSE) ||
       (old_state == NETCONN_CONNECT)) {
     /* calling do_writemore/do_close_internal is not necessary
@@ -721,8 +728,9 @@ do_close_internal(struct netconn *conn)
     conn->state = NETCONN_NONE;
     /* Set back some callback pointers as conn is going away */
     conn->pcb.tcp = NULL;
-    /* @todo: this lets select make the socket readable and writable,
-       which is wrong! errfd instead? */
+    /* Trigger select() in socket layer. Make sure everybody notices activity
+       on the connection, error first! */
+    API_EVENT(conn, NETCONN_EVT_ERROR, 0);
     API_EVENT(conn, NETCONN_EVT_RCVPLUS, 0);
     API_EVENT(conn, NETCONN_EVT_SENDPLUS, 0);
     /* wake up the application task */

src/api/sockets.c

@@ -70,6 +70,8 @@ struct lwip_socket {
   /** number of times data was ACKed (free send buffer), set by event_callback(),
       tested by select */
   u16_t sendevent;
+  /** error happened for this socket, set by event_callback(), tested by select */
+  u16_t errevent; 
   /** last error that occurred on this socket */
   int err;
 };
@@ -227,6 +229,7 @@ alloc_socket(struct netconn *newconn)
       sockets[i].rcvevent   = 0;
       /* TCP sendbuf is empty, but not connected yet, so not yet writable */
       sockets[i].sendevent  = (newconn->type == NETCONN_TCP ? 0 : 1);
+      sockets[i].errevent   = 0;
       sockets[i].err        = 0;
       sys_sem_signal(socksem);
       return i;
@@ -872,10 +875,19 @@ lwip_selscan(int maxfdp1, fd_set *readset, fd_set *writeset, fd_set *exceptset)
         nready++;
       }
     }
+    if (FD_ISSET(i, exceptset)) {
+      /* See if netconn of this socket had an error */
+      p_sock = get_socket(i);
+      if (p_sock && p_sock->errevent) {
+        FD_SET(i, &lexceptset);
+        LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_selscan: fd=%d ready for exception\n", i));
+        nready++;
+      }
+    }
   }
   *readset = lreadset;
   *writeset = lwriteset;
-  FD_ZERO(exceptset);
+  *exceptset = lexceptset;
   
   return nready;
 }
@@ -1087,6 +1099,9 @@ event_callback(struct netconn *conn, enum netconn_evt evt, u16_t len)
     case NETCONN_EVT_SENDMINUS:
       sock->sendevent = 0;
       break;
+    case NETCONN_EVT_ERROR:
+      sock->errevent = 1;
+      break;
     default:
       LWIP_ASSERT("unknown event", 0);
       break;
@@ -1111,6 +1126,9 @@ event_callback(struct netconn *conn, enum netconn_evt evt, u16_t len)
         if (scb->writeset && FD_ISSET(s, scb->writeset))
           if (sock->sendevent)
             break;
+        if (scb->exceptset && FD_ISSET(s, scb->exceptset))
+          if (sock->errevent != 0)
+            break;
       }
     }
     if (scb) {

src/include/lwip/api.h

@@ -89,7 +89,8 @@ enum netconn_evt {
   NETCONN_EVT_RCVPLUS,
   NETCONN_EVT_RCVMINUS,
   NETCONN_EVT_SENDPLUS,
-  NETCONN_EVT_SENDMINUS
+  NETCONN_EVT_SENDMINUS,
+  NETCONN_EVT_ERROR
 };
 
 #if LWIP_IGMP