On Tue, 2006-12-05 at 10:47 +0000, Gustavo J. A. M. Carneiro wrote:
> On Ter, 2006-12-05 at 09:50 +0100, Jules Colding wrote:
> > On Mon, 2006-12-04 at 14:22 +0100, Jules Colding wrote:
> > > Please review and test this patch. I'm not entirely convinced that I
> > > haven't introduced a bad bug or two but at least it works(*) here.
> > 
> > No responses yet, so it seems that my patch is of the usual flawless
> > quality ;-) 
> 
>   Heh :)
>   
>   In fact, the patch sounds really nice, a sign of ORBit2 maturing for
> TCP/IP connections (which is traditionally seldom tested).
> 
>   My only comment is that the changelog entry could use a bit more
> detail.  You only mention changes in one function, but the patch changes
> 4 functions and even adds a new commandline option which deserves a
> mention in the changelog too.

Here is the new and better documented patch.

Best regards,
  jules


Index: ChangeLog
===================================================================
RCS file: /cvs/gnome/ORBit2/ChangeLog,v
retrieving revision 1.778
diff -u -p -r1.778 ChangeLog
--- ChangeLog   22 Nov 2006 20:34:39 -0000      1.778
+++ ChangeLog   5 Dec 2006 12:04:04 -0000
@@ -1,3 +1,95 @@
+2006-12-05  Jules Colding  <[EMAIL PROTECTED]>
+
+       * ORBit2: The previous two ChangeLog entries are hiding a lot of 
+       details which I'll hereby try to expand upon. 
+
+       The rationale for these changes is that any and all occurrences of 
+       g_cond_wait() in ORBit2 has the potential to block forever if it 
+       waits for a connection attempt to complete if said connection 
+       attempt is made towards a remote server which happens to be 
+       physically disconnected or powered off. 
+
+       This blocking behavior can be demonstrated by invoking an operation 
+       on a remote object that is physically inaccessible such as when
+       the remote server is powered down or physically disconnected.
+
+       Pseudo code:
+       
+       {
+           CORBA_ORB orb = get_orb();
+           char *objref = get_corbaloc_str();
+           CORBA_Object obj = CORBA_OBJECT_NIL;
+           CORBA_Environment ev[1];
+       
+           CORBA_exception_init(ev);
+           obj = CORBA_ORB_string_to_object(orb, objref, ev);
+
+           FOO_INTERFACE_method(obj, <arguments>, ev); 
+       }
+
+       The last statement above will block forever in g_cond_wait() while
+       waiting for the recieve buffer to be ready if the remote server is, 
+       say, powered down. An exception is on the other hand immediately 
+       thrown if the server object is merely gone.
+
+       The changes to the code therefore boils down to the implementation 
+       of the ex_CORBA_TIMEOUT system exception being thrown if 
+       g_cond_timed_wait() times out. Most occurrences of g_cond_wait() 
+       has been replaced by g_cond_timed_wait(). 
+
+       The only remaining instance of g_cond_wait() is found in 
+       link_exec_command(). I haven't observed any problems with 
+       link_exec_command() so I've not touched that code.
+
+       The affected code is:
+
+       1) A new ORB command line option: GIOPTimeoutLimit - timeout limit 
+       in microseconds. Defaults to 30 seconds.
+
+       2) giop_recv_buffer_get(). This one is obvious. We do not want to 
+       wait indefinitely for data to be received from a downed host. The 
+       waiting interval is configurable with the new GIOPTimeoutLimit ORB 
+       option.
+
+       3) Any code invoking link_wait():
+
+          a) link_connection_wait_connected_T()
+          b) link_connection_try_reconnect()
+          c) giop_connection_try_reconnect(), calls 
link_connection_try_reconnect()
+          d) ORBit_try_connection_T(), calls giop_connection_try_reconnect()
+          e) ORBit_object_get_connection(), calls ORBit_try_connection_T()
+
+       4) The waiting time in link_wait() is set at compile time to 
+       LINK_WAIT_TIMEOUT_USEC which is presently 10 seconds.
+
+       5) link_wait() has been modified to return a gboolean. FALSE if the
+       timeout expired, TRUE otherwise.
+
+       6) link_connection_wait_connected_T() and 
link_connection_try_reconnect() 
+       will both disconnect the connection if link_wait() experienced a 
timeout.
+
+2006-12-04  Jules Colding  <[EMAIL PROTECTED]>
+
+       * configure.in: Added autoconf 2.60+ required datarootdir variable
+
+2006-12-03  Jules Colding  <[EMAIL PROTECTED]>
+
+       * include/orbit/GIOP/giop.h: Declare giop_recv_set_timeout().
+
+       * src/orb/orb-core/corba-orb.c (CORBA_ORB_init): Set GIOP timeout 
+       limit from the ORB option.
+       Added new ORB option - GIOPTimeoutLimit.
+
+       * src/orb/orb-core/orbit-small.c (ORBit_small_invoke_stub): Throw a 
+       TIMEOUT exception if a reply hasn't been recieved within the GIOP
+       timeout limit.
+
+       * src/orb/GIOP/giop-recv-buffer.c (giop_recv_buffer_get): Replaced 
+       a g_cond_wait() with a g_cond_timed_wait(). The original g_cond_wait()
+       could potentially block forever if a remote server was physically
+       offline.
+       (giop_recv_set_timeout): Function to adjust the GIOP timeout limit.
+
 2006-11-22  Kjartan Maraas  <[EMAIL PROTECTED]>
 
        * ORBit-2.0.pc.in: Move MINGW_CFLAGS and LIBM to Libs.private
Index: configure.in
===================================================================
RCS file: /cvs/gnome/ORBit2/configure.in,v
retrieving revision 1.175
diff -u -p -r1.175 configure.in
--- configure.in        22 Nov 2006 20:34:41 -0000      1.175
+++ configure.in        5 Dec 2006 12:04:04 -0000
@@ -37,6 +37,9 @@ AM_CONFIG_HEADER(config.h)
 dnl Initialize automake stuff
 AM_INIT_AUTOMAKE(ORBit2, $ORBIT_VERSION, no-define)
 
+dnl Required by autoconf 2.60
+AC_SUBST(datarootdir)
+
 AC_CANONICAL_HOST
 AC_MSG_CHECKING([for Win32])
 case "$host" in
Index: include/orbit/GIOP/giop-recv-buffer.h
===================================================================
RCS file: /cvs/gnome/ORBit2/include/orbit/GIOP/giop-recv-buffer.h,v
retrieving revision 1.33
diff -u -p -r1.33 giop-recv-buffer.h
--- include/orbit/GIOP/giop-recv-buffer.h       14 Jan 2004 11:04:01 -0000      
1.33
+++ include/orbit/GIOP/giop-recv-buffer.h       5 Dec 2006 12:04:04 -0000
@@ -58,7 +58,8 @@ void            giop_recv_list_setup_que
 void            giop_recv_list_setup_queue_entry_async (GIOPMessageQueueEntry 
*ent,
                                                        GIOPAsyncCallback      
cb);
 
-GIOPRecvBuffer *giop_recv_buffer_get               (GIOPMessageQueueEntry 
*ent);
+GIOPRecvBuffer *giop_recv_buffer_get               (GIOPMessageQueueEntry *ent,
+                                                   gboolean *timeout);
 void            giop_recv_buffer_unuse             (GIOPRecvBuffer        
*buf);
 
 #define giop_recv_buffer_reply_status(buf) (                                   
         \
Index: include/orbit/GIOP/giop-types.h
===================================================================
RCS file: /cvs/gnome/ORBit2/include/orbit/GIOP/giop-types.h,v
retrieving revision 1.21
diff -u -p -r1.21 giop-types.h
--- include/orbit/GIOP/giop-types.h     27 Oct 2003 16:14:12 -0000      1.21
+++ include/orbit/GIOP/giop-types.h     5 Dec 2006 12:04:04 -0000
@@ -35,7 +35,9 @@ struct _GIOPThread {
                                        gpointer dummy);
 };
 
-#define GIOP_INITIAL_MSG_SIZE_LIMIT 256*1024
+#define GIOP_INITIAL_TIMEOUT_LIMIT (30000000) /* 30 seconds */
+
+#define GIOP_INITIAL_MSG_SIZE_LIMIT (256*1024) /* in bytes */
 
 typedef enum {
        GIOP_CONNECTION_SSL
Index: include/orbit/GIOP/giop.h
===================================================================
RCS file: /cvs/gnome/ORBit2/include/orbit/GIOP/giop.h,v
retrieving revision 1.24
diff -u -p -r1.24 giop.h
--- include/orbit/GIOP/giop.h   5 Apr 2006 07:16:10 -0000       1.24
+++ include/orbit/GIOP/giop.h   5 Dec 2006 12:04:04 -0000
@@ -23,6 +23,7 @@ gboolean    giop_thread_safe       (void
 gboolean    giop_thread_io         (void);
 GIOPThread *giop_thread_self       (void);
 void        giop_invoke_async      (GIOPMessageQueueEntry *ent);
+void        giop_recv_set_timeout  (const glong timeout);
 void        giop_recv_set_limit    (glong limit);
 glong       giop_recv_get_limit    (void);
 void        giop_incoming_signal_T (GIOPThread *tdata, GIOPMsgType t);
@@ -45,6 +46,7 @@ void        giop_thread_new_check       
 void        giop_thread_queue_process    (GIOPThread *tdata);
 gboolean    giop_thread_queue_empty_T    (GIOPThread *tdata);
 void        giop_thread_queue_tail_wakeup(GIOPThread *tdata);
+
 
 #endif /* ORBIT2_INTERNAL_API */
 
Index: linc2/ChangeLog
===================================================================
RCS file: /cvs/gnome/ORBit2/linc2/ChangeLog,v
retrieving revision 1.262
diff -u -p -r1.262 ChangeLog
--- linc2/ChangeLog     22 Nov 2006 19:13:41 -0000      1.262
+++ linc2/ChangeLog     5 Dec 2006 12:04:05 -0000
@@ -1,3 +1,8 @@
+2006-12-04  Jules Colding  <[EMAIL PROTECTED]>
+
+       * src/linc.c (link_wait): Do not wait forever for the link
+       condition to get signaled.
+
 2006-11-22  Kjartan Maraas  <[EMAIL PROTECTED]>
 
        * src/Makefile.am: Remove SSL_LIBS and SSL_CFLAGS.
Index: linc2/include/linc/linc.h
===================================================================
RCS file: /cvs/gnome/ORBit2/linc2/include/linc/linc.h,v
retrieving revision 1.17
diff -u -p -r1.17 linc.h
--- linc2/include/linc/linc.h   28 Jan 2005 12:34:57 -0000      1.17
+++ linc2/include/linc/linc.h   5 Dec 2006 12:04:05 -0000
@@ -33,7 +33,7 @@ GMainLoop *link_main_get_loop    (void);
 guint      link_main_idle_add    (GSourceFunc function,
                                  gpointer    data);
 
-void       link_wait             (void);
+gboolean   link_wait             (void);
 void       link_signal           (void);
 
 gboolean   link_thread_io        (void);
Index: linc2/src/linc-connection.c
===================================================================
RCS file: /cvs/gnome/ORBit2/linc2/src/linc-connection.c,v
retrieving revision 1.117
diff -u -p -r1.117 linc-connection.c
--- linc2/src/linc-connection.c 9 Sep 2006 07:54:37 -0000       1.117
+++ linc2/src/linc-connection.c 5 Dec 2006 12:04:06 -0000
@@ -635,8 +635,10 @@ link_connection_do_initiate (LinkConnect
 static LinkConnectionStatus
 link_connection_wait_connected_T (LinkConnection *cnx)
 {
-       while (cnx && cnx->status == LINK_CONNECTING)
-               link_wait ();
+       while (cnx && cnx->status == LINK_CONNECTING) {
+               if (!link_wait ())
+                       link_connection_disconnect (cnx);
+       }
 
        return cnx ? cnx->status : LINK_DISCONNECTED;
 }
@@ -659,8 +661,12 @@ link_connection_try_reconnect (LinkConne
                        cnx->inhibit_reconnect = FALSE;
                        dispatch_callbacks_drop_lock (cnx);
                        g_main_context_release (NULL);
-               } else 
-                       link_wait ();
+               } else {
+                       if (!link_wait ()) {
+                               link_connection_disconnect (cnx);
+                               break;
+                       }
+               }
        }
 
        if (cnx->status != LINK_DISCONNECTED)
Index: linc2/src/linc.c
===================================================================
RCS file: /cvs/gnome/ORBit2/linc2/src/linc.c,v
retrieving revision 1.63
diff -u -p -r1.63 linc.c
--- linc2/src/linc.c    2 Jun 2006 08:14:22 -0000       1.63
+++ linc2/src/linc.c    5 Dec 2006 12:04:06 -0000
@@ -52,6 +52,9 @@ SSL_METHOD *link_ssl_method;
 SSL_CTX    *link_ssl_ctx;
 #endif
 
+/* max time to wait for the link condition to get signaled - 10 seconds */
+#define LINK_WAIT_TIMEOUT_USEC (10000000) 
+
 static void link_dispatch_command (gpointer data, gboolean immediate);
 
 gboolean
@@ -534,17 +537,28 @@ link_signal (void)
        }
 }
 
-void
+gboolean
 link_wait (void)
 {
+       GTimeVal gtime;
+
        if (!(link_is_thread_safe && link_is_io_in_thread)) {
                link_unlock ();
                link_main_iteration (TRUE);
                link_lock ();
        } else {
                g_assert (link_main_cond != NULL);
-               g_cond_wait (link_main_cond, link_main_lock);
+
+               g_get_current_time (&gtime);
+               g_time_val_add (&gtime, LINK_WAIT_TIMEOUT_USEC);
+               if (!g_cond_timed_wait (link_main_cond, link_main_lock, 
&gtime)) {
+                       if (link_is_locked ())
+                               link_unlock ();
+                       return FALSE;
+               }
        }
+
+       return TRUE;
 }
 
 
Index: src/orb/GIOP/giop-recv-buffer.c
===================================================================
RCS file: /cvs/gnome/ORBit2/src/orb/GIOP/giop-recv-buffer.c,v
retrieving revision 1.81
diff -u -p -r1.81 giop-recv-buffer.c
--- src/orb/GIOP/giop-recv-buffer.c     5 Apr 2006 07:17:17 -0000       1.81
+++ src/orb/GIOP/giop-recv-buffer.c     5 Dec 2006 12:04:07 -0000
@@ -690,10 +690,21 @@ check_got (GIOPMessageQueueEntry *ent)
                (ent->cnx->parent.status == LINK_DISCONNECTED));
 }
 
+static glong giop_initial_timeout_limit = GIOP_INITIAL_TIMEOUT_LIMIT;
+
+void
+giop_recv_set_timeout (const glong timeout)
+{
+       if (0 < timeout) /* We really do not want (timeout <= 0) as that would 
potentially block forever */
+               giop_initial_timeout_limit = timeout;
+}
+
 GIOPRecvBuffer *
-giop_recv_buffer_get (GIOPMessageQueueEntry *ent)
+giop_recv_buffer_get (GIOPMessageQueueEntry *ent,
+                     gboolean *timeout)
 {
        GIOPThread *tdata = giop_thread_self ();
+       GTimeVal tval;
 
  thread_switch:
        if (giop_thread_io ()) {
@@ -704,8 +715,17 @@ giop_recv_buffer_get (GIOPMessageQueueEn
                                ent_unlock (ent);
                                giop_thread_queue_process (tdata);
                                ent_lock (ent);
-                       } else
-                               g_cond_wait (tdata->incoming, tdata->lock);
+                       } else {
+                               if (0 < giop_initial_timeout_limit) {
+                                       g_get_current_time (&tval);
+                                       g_time_val_add (&tval, 
giop_initial_timeout_limit);
+                               }
+                               if (!g_cond_timed_wait (tdata->incoming, 
tdata->lock, ((0 < giop_initial_timeout_limit) ? &tval : NULL))) {
+                                       *timeout = TRUE;
+                                       break;
+                               } else
+                                       *timeout = FALSE;
+                       }
                }
                
                ent_unlock (ent);
@@ -1352,3 +1372,4 @@ giop_recv_buffer_use_buf (GIOPConnection
 
        return buf;
 }
+
Index: src/orb/orb-core/corba-orb.c
===================================================================
RCS file: /cvs/gnome/ORBit2/src/orb/orb-core/corba-orb.c,v
retrieving revision 1.123
diff -u -p -r1.123 corba-orb.c
--- src/orb/orb-core/corba-orb.c        16 Aug 2006 09:28:30 -0000      1.123
+++ src/orb/orb-core/corba-orb.c        5 Dec 2006 12:04:07 -0000
@@ -61,7 +61,7 @@ static char        *orbit_debug_options 
 static char        *orbit_naming_ref         = NULL;
 static GSList      *orbit_initref_list       = NULL; 
 static gboolean     orbit_use_corbaloc       = FALSE;
-
+static gint         orbit_timeout_limit      = -1;
 void
 ORBit_ORB_start_servers (CORBA_ORB orb)
 {
@@ -417,8 +417,8 @@ CORBA_ORB_init (int *argc, char **argv,
        }
 #endif /* G_ENABLE_DEBUG */
 
-
        giop_recv_set_limit (orbit_initial_recv_limit);
+       giop_recv_set_timeout (orbit_timeout_limit);
        giop_init (thread_safe,
                   orbit_use_ipv4 || orbit_use_ipv6 ||
                   orbit_use_irda || orbit_use_ssl);
@@ -1467,6 +1467,7 @@ const ORBit_option orbit_supported_optio
        { "ORBDebugFlags",      ORBIT_OPTION_STRING,  &orbit_debug_options },
        { "ORBInitRef",         ORBIT_OPTION_KEY_VALUE,  &orbit_initref_list},
        { "ORBCorbaloc",        ORBIT_OPTION_BOOLEAN, &orbit_use_corbaloc},
+       { "GIOPTimeoutLimit",   ORBIT_OPTION_INT,     &orbit_timeout_limit },
        { NULL,                 0,                    NULL },
 };
 
Index: src/orb/orb-core/orbit-small.c
===================================================================
RCS file: /cvs/gnome/ORBit2/src/orb/orb-core/orbit-small.c,v
retrieving revision 1.97
diff -u -p -r1.97 orbit-small.c
--- src/orb/orb-core/orbit-small.c      18 May 2006 14:20:49 -0000      1.97
+++ src/orb/orb-core/orbit-small.c      5 Dec 2006 12:04:08 -0000
@@ -591,6 +591,7 @@ ORBit_small_invoke_stub (CORBA_Object   
        GIOPRecvBuffer         *recv_buffer = NULL;
        CORBA_Object            xt_proxy = CORBA_OBJECT_NIL;
        ORBitPolicy            *invoke_policy = CORBA_OBJECT_NIL;
+       gboolean                timeout = FALSE;
 
        if (!obj) {
                dprintf (MESSAGES, "Cannot invoke method on null object\n");
@@ -654,7 +655,9 @@ ORBit_small_invoke_stub (CORBA_Object   
                goto clean_out;
        }
 
-       recv_buffer = giop_recv_buffer_get (&mqe);
+       recv_buffer = giop_recv_buffer_get (&mqe, &timeout);
+       if (timeout)
+               goto timeout_exception;
 
        switch (orbit_small_demarshal (obj, &cnx, recv_buffer, ev,
                                       ret, m_data, args))
@@ -698,6 +701,12 @@ ORBit_small_invoke_stub (CORBA_Object   
        tprintf ("[System exception comm failure] )");
        CORBA_exception_set_system (ev, ex_CORBA_COMM_FAILURE,
                                    completion_status);
+       goto clean_out;
+
+ timeout_exception:
+       tprintf ("[System exception timeout] )");
+       CORBA_exception_set_system (ev, ex_CORBA_TIMEOUT,
+                                   CORBA_COMPLETED_NO);
        goto clean_out;
 }
 


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