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Diffstat (limited to 'src/VBox/Runtime/r3/posix/semwait.h')
| -rw-r--r-- | src/VBox/Runtime/r3/posix/semwait.h | 162 |
1 files changed, 162 insertions, 0 deletions
diff --git a/src/VBox/Runtime/r3/posix/semwait.h b/src/VBox/Runtime/r3/posix/semwait.h new file mode 100644 index 00000000..ade8c4a7 --- /dev/null +++ b/src/VBox/Runtime/r3/posix/semwait.h @@ -0,0 +1,162 @@ +/* $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 */ + |