newlib/winsup/cygwin/cygwait.cc
Corinna Vinschen c43e9340f1 Fix race condition when waiting for a signal
* cygtls.h (_cygtls::wait_signal_arrived): Renamed from
        set_signal_arrived.
        (_cygtls::set_signal_arrived): New function signalling signal_arrived.
        (_cygtls::reset_signal_arrived): Don't reset will_wait_for_signal.
        (_cygtls::unwait_signal_arrived): New function only resetting
        will_wait_for_signal.
        (class wait_signal_arrived): Rename from set_signal_arrived.
        Accommodate name change throughout Cygwin.
        (wait_signal_arrived::~wait_signal_arrived): Call
        _cygtls::unwait_signal_arrived.  Add comment.
        * cygserver_ipc.h (ipc_set_proc_info): Fetch signal_arrived handle
        via call to _cygtls::get_signal_arrived.
        * exceptions.cc (_cygtls::interrupt_setup): Signal signal_arrived via
        call to _cygtls::set_signal_arrived.
        (_cygtls::handle_SIGCONT): Ditto.
        * fhandler_socket.cc (fhandler_socket::wait_for_events): Generate
        WSAEVENT array prior to entering wait loop.  Add cancel event object
        if available.  Remove calls to pthread_testcancel and just call
        pthread::static_cancel_self if the cancel event object is signalled.

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
2015-11-27 14:39:11 +01:00

118 lines
3.2 KiB
C++

/* cygwait.h
Copyright 2011, 2012, 2013, 2015 Red Hat, Inc.
This file is part of Cygwin.
This software is a copyrighted work licensed under the terms of the
Cygwin license. Please consult the file "CYGWIN_LICENSE" for
details. */
#include "winsup.h"
#include "sigproc.h"
#include "cygwait.h"
#include "ntdll.h"
#define is_cw_cancel (mask & cw_cancel)
#define is_cw_cancel_self (mask & cw_cancel_self)
#define is_cw_sig (mask & cw_sig)
#define is_cw_sig_eintr (mask & cw_sig_eintr)
#define is_cw_sig_cont (mask & cw_sig_cont)
#define is_cw_sig_restart (mask & cw_sig_restart)
#define is_cw_sig_handle (mask & (cw_sig | cw_sig_eintr \
| cw_sig_cont | cw_sig_restart))
LARGE_INTEGER cw_nowait_storage;
DWORD
cygwait (HANDLE object, PLARGE_INTEGER timeout, unsigned mask)
{
DWORD res;
DWORD num = 0;
HANDLE wait_objects[4];
pthread_t thread = pthread::self ();
/* Do not change the wait order.
The object must have higher priority than the cancel event,
because WaitForMultipleObjects will return the smallest index
if both objects are signaled. */
if (object)
wait_objects[num++] = object;
wait_signal_arrived thread_waiting (is_cw_sig_handle, wait_objects[num]);
debug_only_printf ("object %p, thread waiting %d, signal_arrived %p", object, (int) thread_waiting, _my_tls.signal_arrived);
DWORD sig_n;
if (!thread_waiting)
sig_n = WAIT_TIMEOUT + 1;
else
sig_n = WAIT_OBJECT_0 + num++;
DWORD cancel_n;
if (!is_cw_cancel || !pthread::is_good_object (&thread) ||
thread->cancelstate == PTHREAD_CANCEL_DISABLE)
cancel_n = WAIT_TIMEOUT + 1;
else
{
cancel_n = WAIT_OBJECT_0 + num++;
wait_objects[cancel_n] = thread->cancel_event;
}
DWORD timeout_n;
if (!timeout)
timeout_n = WAIT_TIMEOUT + 1;
else
{
timeout_n = WAIT_OBJECT_0 + num++;
if (!_my_tls.locals.cw_timer)
NtCreateTimer (&_my_tls.locals.cw_timer, TIMER_ALL_ACCESS, NULL,
NotificationTimer);
NtSetTimer (_my_tls.locals.cw_timer, timeout, NULL, NULL, FALSE, 0, NULL);
wait_objects[timeout_n] = _my_tls.locals.cw_timer;
}
while (1)
{
res = WaitForMultipleObjects (num, wait_objects, FALSE, INFINITE);
debug_only_printf ("res %d", res);
if (res == cancel_n)
res = WAIT_CANCELED;
else if (res == timeout_n)
res = WAIT_TIMEOUT;
else if (res != sig_n)
/* all set */;
else
{
int sig = _my_tls.sig;
if (is_cw_sig_cont && sig == SIGCONT)
_my_tls.sig = 0;
if (!sig)
continue;
if (is_cw_sig_eintr || (is_cw_sig_cont && sig == SIGCONT))
;
else if (_my_tls.call_signal_handler () || is_cw_sig_restart)
continue;
res = WAIT_SIGNALED; /* caller will deal with signals */
}
break;
}
if (timeout)
{
TIMER_BASIC_INFORMATION tbi;
NtQueryTimer (_my_tls.locals.cw_timer, TimerBasicInformation, &tbi,
sizeof tbi, NULL);
/* if timer expired, TimeRemaining is negative and represents the
system uptime when signalled */
if (timeout->QuadPart < 0LL)
timeout->QuadPart = tbi.SignalState ? 0LL : tbi.TimeRemaining.QuadPart;
NtCancelTimer (_my_tls.locals.cw_timer, NULL);
}
if (res == WAIT_CANCELED && is_cw_cancel_self)
pthread::static_cancel_self ();
return res;
}