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/* $Id: semwait.h $ */
/** @file
* IPRT - Common semaphore wait code.
*/
/*
* Copyright (C) 2021-2023 Oracle and/or its affiliates.
*
* This file is part of VirtualBox base platform packages, as
* available from https://www.virtualbox.org.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, in version 3 of the
* License.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <https://www.gnu.org/licenses>.
*
* The contents of this file may alternatively be used under the terms
* of the Common Development and Distribution License Version 1.0
* (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
* in the VirtualBox distribution, in which case the provisions of the
* CDDL are applicable instead of those of the GPL.
*
* You may elect to license modified versions of this file under the
* terms and conditions of either the GPL or the CDDL or both.
*
* SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
*/
#ifndef IPRT_INCLUDED_SRC_r3_posix_semwait_h
#define IPRT_INCLUDED_SRC_r3_posix_semwait_h
#ifndef RT_WITHOUT_PRAGMA_ONCE
# pragma once
#endif
/** @def IPRT_HAVE_PTHREAD_CONDATTR_SETCLOCK
* Set if the platform implements pthread_condattr_setclock().
* Enables the use of the monotonic clock for waiting on condition variables. */
#ifndef IPRT_HAVE_PTHREAD_CONDATTR_SETCLOCK
/* Linux detection */
# if defined(RT_OS_LINUX) && defined(__USE_XOPEN2K)
# include <features.h>
# if __GLIBC_PREREQ(2,6) /** @todo figure the exact version where this was added */
# define IPRT_HAVE_PTHREAD_CONDATTR_SETCLOCK
# endif
# endif
/** @todo check other platforms */
#endif
/**
* Converts a extended wait timeout specification to an absolute timespec and a
* relative nanosecond count.
*
* @note This does not check for RTSEMWAIT_FLAGS_INDEFINITE, caller should've
* done that already.
*
* @returns The relative wait in nanoseconds. 0 for a poll call, UINT64_MAX for
* an effectively indefinite wait.
* @param fFlags RTSEMWAIT_FLAGS_XXX.
* @param fMonotonicClock Whether the timeout is in monotonic (true) or real
* (false) time.
* @param uTimeout The timeout.
* @param pAbsDeadline Where to return the absolute deadline.
*/
DECLINLINE(uint64_t) rtSemPosixCalcDeadline(uint32_t fFlags, uint64_t uTimeout, bool fMonotonicClock,
struct timespec *pAbsDeadline)
{
Assert(!(fFlags & RTSEMWAIT_FLAGS_INDEFINITE));
/*
* Convert uTimeout to a relative value in nanoseconds.
*/
if (fFlags & RTSEMWAIT_FLAGS_MILLISECS)
{
if (uTimeout < UINT64_MAX / RT_NS_1MS)
uTimeout = uTimeout * RT_NS_1MS;
else
return UINT64_MAX;
}
else if (uTimeout == UINT64_MAX) /* unofficial way of indicating an indefinite wait */
return UINT64_MAX;
/*
* Make uTimeout relative and check for polling (zero timeout) calls.
*/
uint64_t uAbsTimeout = uTimeout;
if (fFlags & RTSEMWAIT_FLAGS_ABSOLUTE)
{
uint64_t const u64Now = RTTimeSystemNanoTS();
if (uTimeout > u64Now)
uTimeout -= u64Now;
else
return 0;
}
else if (uTimeout == 0)
return 0;
/*
* Calculate the deadline according to the clock we're using.
*/
if (!fMonotonicClock)
{
#if defined(RT_OS_DARWIN) || defined(RT_OS_HAIKU)
struct timeval tv = {0,0};
gettimeofday(&tv, NULL);
pAbsDeadline->tv_sec = tv.tv_sec;
pAbsDeadline->tv_nsec = tv.tv_usec * 1000;
#else
clock_gettime(CLOCK_REALTIME, pAbsDeadline);
#endif
struct timespec TsAdd;
TsAdd.tv_nsec = uTimeout % RT_NS_1SEC;
TsAdd.tv_sec = uTimeout / RT_NS_1SEC;
/* Check for 32-bit tv_sec overflows: */
if ( sizeof(pAbsDeadline->tv_sec) < sizeof(uint64_t)
&& ( uTimeout >= (uint64_t)RT_NS_1SEC * UINT32_MAX
|| (uint64_t)pAbsDeadline->tv_sec + pAbsDeadline->tv_sec >= UINT32_MAX) )
return UINT64_MAX;
pAbsDeadline->tv_sec += TsAdd.tv_sec;
pAbsDeadline->tv_nsec += TsAdd.tv_nsec;
if ((uint32_t)pAbsDeadline->tv_nsec >= RT_NS_1SEC)
{
pAbsDeadline->tv_nsec -= RT_NS_1SEC;
pAbsDeadline->tv_sec++;
}
}
else
{
/* ASSUMES RTTimeSystemNanoTS() == RTTimeNanoTS() == clock_gettime(CLOCK_MONOTONIC). */
if (fFlags & RTSEMWAIT_FLAGS_RELATIVE)
{
uint64_t const nsNow = RTTimeSystemNanoTS();
uAbsTimeout += nsNow;
if (uAbsTimeout < nsNow)
return UINT64_MAX;
}
/* Check for 32-bit tv_sec overflows: */
if ( sizeof(pAbsDeadline->tv_sec) < sizeof(uint64_t)
&& uAbsTimeout >= (uint64_t)RT_NS_1SEC * UINT32_MAX)
return UINT64_MAX;
pAbsDeadline->tv_nsec = uAbsTimeout % RT_NS_1SEC;
pAbsDeadline->tv_sec = uAbsTimeout / RT_NS_1SEC;
}
return uTimeout;
}
#endif /* !IPRT_INCLUDED_SRC_r3_posix_semwait_h */
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