Provide the correct socklen to bind.

Get Brian's patch from #5825 and his log message:
Fix a failure in binding the initiating side of a connection
on MacOS. MacOS doesn't like passing the size of the storage
structure (sockaddr_storage) instead of the expected size of
the structure (sockaddr_in or sockaddr_in6), which was causing
bind() failures. This patch simply changes the structure size
to the expected size.

Add a more clear error message in debug mode.

Signed-off-by: George Bosilca <bosilca@icl.utk.edu>

Author: bosilca

opal/mca/btl/tcp/btl_tcp_endpoint.c

@@ -728,34 +728,39 @@ static int mca_btl_tcp_endpoint_start_connect(mca_btl_base_endpoint_t* btl_endpo
 
     /* start the connect - will likely fail with EINPROGRESS */
     mca_btl_tcp_proc_tosocks(btl_endpoint->endpoint_addr, &endpoint_addr);
-    
+
     /* Bind the socket to one of the addresses associated with
      * this btl module.  This sets the source IP to one of the 
      * addresses shared in modex, so that the destination rank 
      * can properly pair btl modules, even in cases where Linux 
      * might do something unexpected with routing */
-    opal_socklen_t sockaddr_addrlen = sizeof(struct sockaddr_storage);
     if (endpoint_addr.ss_family == AF_INET) {
         assert(NULL != &btl_endpoint->endpoint_btl->tcp_ifaddr);
         if (bind(btl_endpoint->endpoint_sd, (struct sockaddr*) &btl_endpoint->endpoint_btl->tcp_ifaddr,
-		 sockaddr_addrlen) < 0) {
-	    BTL_ERROR(("bind() failed: %s (%d)", strerror(opal_socket_errno), opal_socket_errno));
+                 sizeof(struct sockaddr_in)) < 0) {
+            BTL_ERROR(("bind on local address (%s:%d) failed: %s (%d)",
+                       opal_net_get_hostname((struct sockaddr*) &btl_endpoint->endpoint_btl->tcp_ifaddr),
+                       htons(((struct sockaddr_in*)&btl_endpoint->endpoint_btl->tcp_ifaddr)->sin_port),
+                       strerror(opal_socket_errno), opal_socket_errno));
 
-	    CLOSE_THE_SOCKET(btl_endpoint->endpoint_sd);
-	    return OPAL_ERROR;
-	}
+            CLOSE_THE_SOCKET(btl_endpoint->endpoint_sd);
+            return OPAL_ERROR;
+        }
     }
 #if OPAL_ENABLE_IPV6
     if (endpoint_addr.ss_family == AF_INET6) {
         assert(NULL != &btl_endpoint->endpoint_btl->tcp_ifaddr_6);
         if (bind(btl_endpoint->endpoint_sd, (struct sockaddr*) &btl_endpoint->endpoint_btl->tcp_ifaddr_6,
-	    sockaddr_addrlen) < 0) {
-	    BTL_ERROR(("bind() failed: %s (%d)", strerror(opal_socket_errno), opal_socket_errno));
+                 sizeof(struct sockaddr_in6)) < 0) {
+            BTL_ERROR(("bind on local address (%s:%d) failed: %s (%d)",
+                       opal_net_get_hostname((struct sockaddr*) &btl_endpoint->endpoint_btl->tcp_ifaddr),
+                       htons(((struct sockaddr_in*)&btl_endpoint->endpoint_btl->tcp_ifaddr)->sin_port),
+                       strerror(opal_socket_errno), opal_socket_errno));
 
-	    CLOSE_THE_SOCKET(btl_endpoint->endpoint_sd);
-	    return OPAL_ERROR;
-        }    
-    }  
+            CLOSE_THE_SOCKET(btl_endpoint->endpoint_sd);
+            return OPAL_ERROR;
+        }
+    }
 #endif
     opal_output_verbose(10, opal_btl_base_framework.framework_output,
                         "btl: tcp: attempting to connect() to %s address %s on port %d",