diff options
| -rw-r--r-- | gdb/ChangeLog | 10 | ||||
| -rw-r--r-- | gdb/ser-mingw.c | 141 |
2 files changed, 79 insertions, 72 deletions
diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 9fd45e0..6077c41 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,13 @@ +2014-06-11 Pedro Alves <palves@redhat.com> + + PR remote/17028 + * ser-mingw.c (net_windows_socket_check_pending): New function. + (net_windows_select_thread): Ignore spurious wakeups. Use + net_windows_socket_check_pending. + (net_windows_wait_handle): Check for pending events with + ioctlsocket, through net_windows_socket_check_pending, instead of + checking the socket's event. + 2014-06-10 Siva Chandra Reddy <sivachandra@google.com> * python/python-internal.h (gdb_PyObject_GetAttrString) diff --git a/gdb/ser-mingw.c b/gdb/ser-mingw.c index db04999..a6469ea 100644 --- a/gdb/ser-mingw.c +++ b/gdb/ser-mingw.c @@ -1046,6 +1046,32 @@ struct net_windows_state HANDLE sock_event; }; +/* Check whether the socket has any pending data to be read. If so, + set the select thread's read event. On error, set the select + thread's except event. If any event was set, return true, + otherwise return false. */ + +static int +net_windows_socket_check_pending (struct serial *scb) +{ + struct net_windows_state *state = scb->state; + unsigned long available; + + if (ioctlsocket (scb->fd, FIONREAD, &available) != 0) + { + /* The socket closed, or some other error. */ + SetEvent (state->base.except_event); + return 1; + } + else if (available > 0) + { + SetEvent (state->base.read_event); + return 1; + } + + return 0; +} + static DWORD WINAPI net_windows_select_thread (void *arg) { @@ -1065,33 +1091,54 @@ net_windows_select_thread (void *arg) wait_events[0] = state->base.stop_select; wait_events[1] = state->sock_event; - event_index = WaitForMultipleObjects (2, wait_events, FALSE, INFINITE); - - if (event_index == WAIT_OBJECT_0 - || WaitForSingleObject (state->base.stop_select, 0) == WAIT_OBJECT_0) - /* We have been requested to stop. */ - ; - else if (event_index != WAIT_OBJECT_0 + 1) - /* Some error has occured. Assume that this is an error - condition. */ - SetEvent (state->base.except_event); - else + /* Wait for something to happen on the socket. */ + while (1) { + event_index = WaitForMultipleObjects (2, wait_events, FALSE, INFINITE); + + if (event_index == WAIT_OBJECT_0 + || WaitForSingleObject (state->base.stop_select, 0) == WAIT_OBJECT_0) + { + /* We have been requested to stop. */ + break; + } + + if (event_index != WAIT_OBJECT_0 + 1) + { + /* Some error has occured. Assume that this is an error + condition. */ + SetEvent (state->base.except_event); + break; + } + /* Enumerate the internal network events, and reset the object that signalled us to catch the next event. */ - WSAEnumNetworkEvents (scb->fd, state->sock_event, &events); - - gdb_assert (events.lNetworkEvents & (FD_READ | FD_CLOSE)); - + if (WSAEnumNetworkEvents (scb->fd, state->sock_event, &events) != 0) + { + /* Something went wrong. Maybe the socket is gone. */ + SetEvent (state->base.except_event); + break; + } + if (events.lNetworkEvents & FD_READ) - SetEvent (state->base.read_event); - + { + if (net_windows_socket_check_pending (scb)) + break; + + /* Spurious wakeup. That is, the socket's event was + signalled before we last called recv. */ + } + if (events.lNetworkEvents & FD_CLOSE) - SetEvent (state->base.except_event); + { + SetEvent (state->base.except_event); + break; + } } SetEvent (state->base.have_stopped); } + return 0; } static void @@ -1107,60 +1154,10 @@ net_windows_wait_handle (struct serial *scb, HANDLE *read, HANDLE *except) *read = state->base.read_event; *except = state->base.except_event; - /* Check any pending events. This both avoids starting the thread - unnecessarily, and handles stray FD_READ events (see below). */ - if (WaitForSingleObject (state->sock_event, 0) == WAIT_OBJECT_0) - { - WSANETWORKEVENTS events; - int any = 0; - - /* Enumerate the internal network events, and reset the object that - signalled us to catch the next event. */ - WSAEnumNetworkEvents (scb->fd, state->sock_event, &events); - - /* You'd think that FD_READ or FD_CLOSE would be set here. But, - sometimes, neither is. I suspect that the FD_READ is set and - the corresponding event signalled while recv is running, and - the FD_READ is then lowered when recv consumes all the data, - but there's no way to un-signal the event. This isn't a - problem for the call in net_select_thread, since any new - events after this point will not have been drained by recv. - It just means that we can't have the obvious assert here. */ - - /* If there is a read event, it might be still valid, or it might - not be - it may have been signalled before we last called - recv. Double-check that there is data. */ - if (events.lNetworkEvents & FD_READ) - { - unsigned long available; - - if (ioctlsocket (scb->fd, FIONREAD, &available) == 0 - && available > 0) - { - SetEvent (state->base.read_event); - any = 1; - } - else - /* Oops, no data. This call to recv will cause future - data to retrigger the event, e.g. while we are - in net_select_thread. */ - recv (scb->fd, NULL, 0, 0); - } - - /* If there's a close event, then record it - it is obviously - still valid, and it will not be resignalled. */ - if (events.lNetworkEvents & FD_CLOSE) - { - SetEvent (state->base.except_event); - any = 1; - } - - /* If we set either handle, there's no need to wake the thread. */ - if (any) - return; - } - - start_select_thread (&state->base); + /* Check any pending events. Otherwise, start the select + thread. */ + if (!net_windows_socket_check_pending (scb)) + start_select_thread (&state->base); } static void |