| 1 | /* $Id: semevent-r0drv-linux.c 55251 2009-11-25 14:26:50Z fmehnert $ */
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| 2 | /** @file
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| 3 | * IPRT - Single Release Event Semaphores, Ring-0 Driver, Linux.
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| 4 | */
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| 5 |
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| 6 | /*
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| 7 | * Copyright (C) 2006-2007 Sun Microsystems, Inc.
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| 8 | *
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| 9 | * This file is part of VirtualBox Open Source Edition (OSE), as
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| 10 | * available from http://www.virtualbox.org. This file is free software;
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| 11 | * you can redistribute it and/or modify it under the terms of the GNU
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| 12 | * General Public License (GPL) as published by the Free Software
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| 13 | * Foundation, in version 2 as it comes in the "COPYING" file of the
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| 14 | * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
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| 15 | * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
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| 16 | *
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| 17 | * The contents of this file may alternatively be used under the terms
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| 18 | * of the Common Development and Distribution License Version 1.0
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| 19 | * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
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| 20 | * VirtualBox OSE distribution, in which case the provisions of the
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| 21 | * CDDL are applicable instead of those of the GPL.
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| 22 | *
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| 23 | * You may elect to license modified versions of this file under the
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| 24 | * terms and conditions of either the GPL or the CDDL or both.
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| 25 | *
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| 26 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
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| 27 | * Clara, CA 95054 USA or visit http://www.sun.com if you need
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| 28 | * additional information or have any questions.
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| 29 | */
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| 30 |
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| 31 |
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| 32 | /*******************************************************************************
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| 33 | * Header Files *
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| 34 | *******************************************************************************/
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| 35 | #include "the-linux-kernel.h"
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| 36 | #include "internal/iprt.h"
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| 37 | #include <iprt/semaphore.h>
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| 38 | #include <iprt/alloc.h>
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| 39 | #include <iprt/assert.h>
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| 40 | #include <iprt/asm.h>
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| 41 | #include <iprt/err.h>
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| 42 |
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| 43 | #include "internal/magics.h"
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| 44 |
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| 45 | /* We use the API of Linux 2.6.28+ (schedule_hrtimeout()) */
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| 46 | #if !defined(RT_USE_LINUX_HRTIMER) \
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| 47 | && LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 28) \
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| 48 | && 1 /* currently disabled */
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| 49 | # define RT_USE_LINUX_HRTIMER
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| 50 | #endif
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| 51 |
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| 52 | /*******************************************************************************
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| 53 | * Structures and Typedefs *
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| 54 | *******************************************************************************/
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| 55 | /**
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| 56 | * Linux event semaphore.
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| 57 | */
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| 58 | typedef struct RTSEMEVENTINTERNAL
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| 59 | {
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| 60 | /** Magic value (RTSEMEVENT_MAGIC). */
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| 61 | uint32_t volatile u32Magic;
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| 62 | /** The object status - !0 when signaled and 0 when reset. */
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| 63 | uint32_t volatile fState;
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| 64 | /** The wait queue. */
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| 65 | wait_queue_head_t Head;
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| 66 | } RTSEMEVENTINTERNAL, *PRTSEMEVENTINTERNAL;
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| 67 |
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| 68 |
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| 69 |
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| 70 | RTDECL(int) RTSemEventCreate(PRTSEMEVENT pEventSem)
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| 71 | {
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| 72 | PRTSEMEVENTINTERNAL pEventInt = (PRTSEMEVENTINTERNAL)RTMemAlloc(sizeof(*pEventInt));
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| 73 | if (pEventInt)
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| 74 | {
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| 75 | pEventInt->u32Magic = RTSEMEVENT_MAGIC;
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| 76 | pEventInt->fState = 0;
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| 77 | init_waitqueue_head(&pEventInt->Head);
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| 78 | *pEventSem = pEventInt;
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| 79 | return VINF_SUCCESS;
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| 80 | }
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| 81 | return VERR_NO_MEMORY;
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| 82 | }
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| 83 | RT_EXPORT_SYMBOL(RTSemEventCreate);
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| 84 |
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| 85 |
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| 86 | RTDECL(int) RTSemEventDestroy(RTSEMEVENT EventSem)
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| 87 | {
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| 88 | /*
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| 89 | * Validate input.
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| 90 | */
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| 91 | PRTSEMEVENTINTERNAL pEventInt = (PRTSEMEVENTINTERNAL)EventSem;
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| 92 | if (!pEventInt)
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| 93 | return VERR_INVALID_PARAMETER;
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| 94 | if (pEventInt->u32Magic != RTSEMEVENT_MAGIC)
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| 95 | {
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| 96 | AssertMsgFailed(("pEventInt->u32Magic=%RX32 pEventInt=%p\n", pEventInt->u32Magic, pEventInt));
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| 97 | return VERR_INVALID_PARAMETER;
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| 98 | }
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| 99 |
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| 100 | /*
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| 101 | * Invalidate it and signal the object just in case.
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| 102 | */
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| 103 | ASMAtomicWriteU32(&pEventInt->u32Magic, ~RTSEMEVENT_MAGIC);
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| 104 | ASMAtomicWriteU32(&pEventInt->fState, 0);
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| 105 | Assert(!waitqueue_active(&pEventInt->Head));
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| 106 | wake_up_all(&pEventInt->Head);
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| 107 | RTMemFree(pEventInt);
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| 108 | return VINF_SUCCESS;
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| 109 | }
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| 110 | RT_EXPORT_SYMBOL(RTSemEventDestroy);
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| 111 |
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| 112 |
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| 113 | RTDECL(int) RTSemEventSignal(RTSEMEVENT EventSem)
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| 114 | {
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| 115 | /*
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| 116 | * Validate input.
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| 117 | */
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| 118 | PRTSEMEVENTINTERNAL pEventInt = (PRTSEMEVENTINTERNAL)EventSem;
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| 119 | if (!pEventInt)
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| 120 | return VERR_INVALID_PARAMETER;
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| 121 | if ( !pEventInt
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| 122 | || pEventInt->u32Magic != RTSEMEVENT_MAGIC)
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| 123 | {
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| 124 | AssertMsgFailed(("pEventInt->u32Magic=%RX32 pEventInt=%p\n", pEventInt ? pEventInt->u32Magic : 0, pEventInt));
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| 125 | return VERR_INVALID_PARAMETER;
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| 126 | }
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| 127 |
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| 128 | /*
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| 129 | * Signal the event object.
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| 130 | */
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| 131 | ASMAtomicWriteU32(&pEventInt->fState, 1);
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| 132 | wake_up(&pEventInt->Head);
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| 133 |
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| 134 | return VINF_SUCCESS;
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| 135 | }
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| 136 | RT_EXPORT_SYMBOL(RTSemEventSignal);
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| 137 |
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| 138 |
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| 139 | /**
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| 140 | * Worker for RTSemEvent and RTSemEventNoResume.
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| 141 | *
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| 142 | * @returns VBox status code.
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| 143 | * @param pEventInt The event semaphore.
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| 144 | * @param cMillies The number of milliseconds to wait.
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| 145 | * @param fInterruptible Whether it's an interruptible wait or not.
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| 146 | */
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| 147 | static int rtSemEventWait(PRTSEMEVENTINTERNAL pEventInt, unsigned cMillies, bool fInterruptible)
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| 148 | {
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| 149 | /*
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| 150 | * Ok wait for it.
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| 151 | */
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| 152 | DEFINE_WAIT(Wait);
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| 153 | int rc = VINF_SUCCESS;
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| 154 | #ifndef RT_USE_LINUX_HRTIMER
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| 155 | long lTimeout = cMillies == RT_INDEFINITE_WAIT ? MAX_SCHEDULE_TIMEOUT : msecs_to_jiffies(cMillies);
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| 156 | #else
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| 157 | ktime_t Kt = cMillies == RT_INDEFINITE_WAIT ? ktime_set(KTIME_SEC_MAX, 0) : ktime_add_ns(ktime_get(), cMillies * UINT64_C(1000000));
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| 158 | int rcHr;
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| 159 | #endif
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| 160 | #ifdef IPRT_DEBUG_SEMS
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| 161 | snprintf(current->comm, TASK_COMM_LEN, "e%lx", IPRT_DEBUG_SEMS_ADDRESS(pEventInt));
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| 162 | #endif
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| 163 | for (;;)
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| 164 | {
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| 165 | /* make everything thru schedule_timeout() atomic scheduling wise. */
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| 166 | prepare_to_wait(&pEventInt->Head, &Wait, fInterruptible ? TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE);
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| 167 |
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| 168 | /* check the condition. */
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| 169 | if (ASMAtomicCmpXchgU32(&pEventInt->fState, 0, 1))
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| 170 | break;
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| 171 |
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| 172 | /* check for pending signals. */
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| 173 | if (fInterruptible && signal_pending(current))
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| 174 | {
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| 175 | rc = VERR_INTERRUPTED;
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| 176 | break;
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| 177 | }
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| 178 |
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| 179 | #ifdef RT_USE_LINUX_HRTIMER
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| 180 | rcHr = schedule_hrtimeout(&Kt, cMillies == RT_INDEFINITE_WAIT ? HRTIMER_MODE_REL : HRTIMER_MODE_ABS);
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| 181 | #else
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| 182 | /* wait */
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| 183 | lTimeout = schedule_timeout(lTimeout);
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| 184 | #endif
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| 185 |
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| 186 | after_wait(&Wait);
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| 187 |
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| 188 | /* Check if someone destroyed the semaphore while we were waiting. */
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| 189 | if (pEventInt->u32Magic != RTSEMEVENT_MAGIC)
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| 190 | {
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| 191 | rc = VERR_SEM_DESTROYED;
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| 192 | break;
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| 193 | }
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| 194 |
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| 195 | #ifdef RT_USE_LINUX_HRTIMER
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| 196 | if (!rcHr)
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| 197 | {
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| 198 | rc = VERR_TIMEOUT;
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| 199 | break;
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| 200 | }
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| 201 | #else
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| 202 | /* check for timeout. */
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| 203 | if (!lTimeout)
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| 204 | {
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| 205 | rc = VERR_TIMEOUT;
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| 206 | break;
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| 207 | }
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| 208 | #endif
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| 209 | }
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| 210 |
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| 211 | finish_wait(&pEventInt->Head, &Wait);
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| 212 | #ifdef IPRT_DEBUG_SEMS
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| 213 | snprintf(current->comm, TASK_COMM_LEN, "e%lx:%d", IPRT_DEBUG_SEMS_ADDRESS(pEventInt), rc);
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| 214 | #endif
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| 215 | return rc;
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| 216 | }
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| 217 |
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| 218 |
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| 219 | RTDECL(int) RTSemEventWait(RTSEMEVENT EventSem, unsigned cMillies)
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| 220 | {
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| 221 | PRTSEMEVENTINTERNAL pEventInt = (PRTSEMEVENTINTERNAL)EventSem;
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| 222 | if (!pEventInt)
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| 223 | return VERR_INVALID_PARAMETER;
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| 224 | if ( !pEventInt
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| 225 | || pEventInt->u32Magic != RTSEMEVENT_MAGIC)
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| 226 | {
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| 227 | AssertMsgFailed(("pEventInt->u32Magic=%RX32 pEventInt=%p\n", pEventInt ? pEventInt->u32Magic : 0, pEventInt));
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| 228 | return VERR_INVALID_PARAMETER;
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| 229 | }
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| 230 |
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| 231 | if (ASMAtomicCmpXchgU32(&pEventInt->fState, 0, 1))
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| 232 | return VINF_SUCCESS;
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| 233 | return rtSemEventWait(pEventInt, cMillies, false /* fInterruptible */);
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| 234 | }
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| 235 | RT_EXPORT_SYMBOL(RTSemEventWait);
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| 236 |
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| 237 |
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| 238 | RTDECL(int) RTSemEventWaitNoResume(RTSEMEVENT EventSem, unsigned cMillies)
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| 239 | {
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| 240 | PRTSEMEVENTINTERNAL pEventInt = (PRTSEMEVENTINTERNAL)EventSem;
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| 241 | if (!pEventInt)
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| 242 | return VERR_INVALID_PARAMETER;
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| 243 | if ( !pEventInt
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| 244 | || pEventInt->u32Magic != RTSEMEVENT_MAGIC)
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| 245 | {
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| 246 | AssertMsgFailed(("pEventInt->u32Magic=%RX32 pEventInt=%p\n", pEventInt ? pEventInt->u32Magic : 0, pEventInt));
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| 247 | return VERR_INVALID_PARAMETER;
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| 248 | }
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| 249 |
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| 250 | if (ASMAtomicCmpXchgU32(&pEventInt->fState, 0, 1))
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| 251 | return VINF_SUCCESS;
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| 252 | return rtSemEventWait(pEventInt, cMillies, true /* fInterruptible */);
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| 253 | }
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| 254 | RT_EXPORT_SYMBOL(RTSemEventWaitNoResume);
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| 255 |
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