newlib/winsup/cygwin/cygwait.cc

/* cygwait.h

   Copyright 2011, 2012 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_return	(mask & cw_sig_return)

#define is_cw_sig_handle	(mask & (is_cw_sig | is_cw_sig_eintr))

DWORD
cancelable_wait (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;

  DWORD sig_n;
  if (!is_cw_sig_handle)
    sig_n = WAIT_TIMEOUT + 1;
  else
    {
      sig_n = WAIT_OBJECT_0 + num++;
      wait_objects[sig_n] = signal_arrived;
    }

  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);
      if (res == cancel_n)
	res = WAIT_CANCELED;
      else if (res == timeout_n)
	res = WAIT_TIMEOUT;
      else if (res != sig_n)
	/* all set */;
      else if (is_cw_sig_eintr)
	res = WAIT_SIGNALED;	/* caller will deal with signals */
      else if (_my_tls.call_signal_handler () || &_my_tls != _main_tls)
	continue;
      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;
}