Attachment 17866 Details for Bug 16841 – [PATCH 5/9] Fix issue where timeouts can overflow.

[patch] [PATCH 5/9] Fix issue where timeouts can overflow.

005.patch (text/plain), 2.95 KB, created by Colin Walters on 2008-07-24 15:07:39 UTC

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Creator: Colin Walters

Created: 2008-07-24 15:07:39 UTC

Size: 2.95 KB

patch

obsolete

>* dbus/dbus-connection.c (_dbus_connection_block_pending_call): Rework
>  the timeout math so instead of calculating an end time, which may overflow,
>  we instead calculate the elapsed time which is always smaller than the
>  boundaries.
>---
> dbus/dbus-connection.c |   21 +++++++--------------
> 1 files changed, 7 insertions(+), 14 deletions(-)
>
>diff --git a/dbus/dbus-connection.c b/dbus/dbus-connection.c
>index 49766e8..546dd40 100644
>--- a/dbus/dbus-connection.c
>+++ b/dbus/dbus-connection.c
>@@ -2265,13 +2265,12 @@ void
> _dbus_connection_block_pending_call (DBusPendingCall *pending)
> {
>   long start_tv_sec, start_tv_usec;
>-  long end_tv_sec, end_tv_usec;
>   long tv_sec, tv_usec;
>   DBusDispatchStatus status;
>   DBusConnection *connection;
>   dbus_uint32_t client_serial;
>   DBusTimeout *timeout;
>-  int timeout_milliseconds;
>+  int timeout_milliseconds, elapsed_milliseconds;
> 
>   _dbus_assert (pending != NULL);
> 
>@@ -2295,18 +2294,12 @@ _dbus_connection_block_pending_call (DBusPendingCall *pending)
>   if (timeout)
>     {
>       timeout_milliseconds = dbus_timeout_get_interval (timeout);
>-      
>       _dbus_get_current_time (&start_tv_sec, &start_tv_usec);
>-      end_tv_sec = start_tv_sec + timeout_milliseconds / 1000;
>-      end_tv_usec = start_tv_usec + (timeout_milliseconds % 1000) * 1000;
>-      end_tv_sec += end_tv_usec / _DBUS_USEC_PER_SECOND;
>-      end_tv_usec = end_tv_usec % _DBUS_USEC_PER_SECOND;
> 
>-      _dbus_verbose ("dbus_connection_send_with_reply_and_block(): will block %d milliseconds for reply serial %u from %ld sec %ld usec to %ld sec %ld usec\n",
>+      _dbus_verbose ("dbus_connection_send_with_reply_and_block(): will block %d milliseconds for reply serial %u from %ld sec %ld usec\n",
>                      timeout_milliseconds,
>                      client_serial,
>-                     start_tv_sec, start_tv_usec,
>-                     end_tv_sec, end_tv_usec);
>+                     start_tv_sec, start_tv_usec);
>     }
>   else
>     {
>@@ -2355,6 +2348,8 @@ _dbus_connection_block_pending_call (DBusPendingCall *pending)
>     }
>   
>   _dbus_get_current_time (&tv_sec, &tv_usec);
>+  elapsed_milliseconds = (tv_sec - start_tv_sec) * 1000 +
>+	  (tv_usec - start_tv_usec) / 1000;
>   
>   if (!_dbus_connection_get_is_connected_unlocked (connection))
>     {
>@@ -2396,11 +2391,9 @@ _dbus_connection_block_pending_call (DBusPendingCall *pending)
>     }
>   else if (tv_sec < start_tv_sec)
>     _dbus_verbose ("dbus_connection_send_with_reply_and_block(): clock set backward\n");
>-  else if (tv_sec < end_tv_sec ||
>-           (tv_sec == end_tv_sec && tv_usec < end_tv_usec))
>+  else if (elapsed_milliseconds < timeout_milliseconds)
>     {
>-      timeout_milliseconds = (end_tv_sec - tv_sec) * 1000 +
>-        (end_tv_usec - tv_usec) / 1000;
>+      timeout_milliseconds -= elapsed_milliseconds;
>       _dbus_verbose ("dbus_connection_send_with_reply_and_block(): %d milliseconds remain\n", timeout_milliseconds);
>       _dbus_assert (timeout_milliseconds >= 0);
>       
>-- 
>1.5.4.3

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