/* $Id: semevent-r0drv-nt.cpp $ */
/** @file
 * IPRT -  Single Release Event Semaphores, Ring-0 Driver, NT.
 */

/*
 * Copyright (C) 2006-2007 Oracle Corporation
 *
 * This file is part of VirtualBox Open Source Edition (OSE), as
 * available from http://www.virtualbox.org. This file is free software;
 * you can redistribute it and/or modify it under the terms of the GNU
 * General Public License (GPL) as published by the Free Software
 * Foundation, in version 2 as it comes in the "COPYING" file of the
 * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
 * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
 *
 * The contents of this file may alternatively be used under the terms
 * of the Common Development and Distribution License Version 1.0
 * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
 * VirtualBox OSE 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.
 */



/*******************************************************************************
*   Header Files                                                               *
*******************************************************************************/
#include "the-nt-kernel.h"
#include <iprt/semaphore.h>
#include <iprt/alloc.h>
#include <iprt/assert.h>
#include <iprt/asm.h>
#include <iprt/err.h>

#include "internal/magics.h"


/*******************************************************************************
*   Structures and Typedefs                                                    *
*******************************************************************************/
/**
 * NT event semaphore.
 */
typedef struct RTSEMEVENTINTERNAL
{
    /** Magic value (RTSEMEVENT_MAGIC). */
    uint32_t volatile   u32Magic;
    /** The NT Event object. */
    KEVENT              Event;
} RTSEMEVENTINTERNAL, *PRTSEMEVENTINTERNAL;


RTDECL(int)  RTSemEventCreate(PRTSEMEVENT phEventSem)
{
    return RTSemEventCreateEx(phEventSem, 0 /*fFlags*/, NIL_RTLOCKVALCLASS, NULL);
}


RTDECL(int)  RTSemEventCreateEx(PRTSEMEVENT phEventSem, uint32_t fFlags, RTLOCKVALCLASS hClass, const char *pszNameFmt, ...)
{
    AssertReturn(!(fFlags & ~RTSEMEVENT_FLAGS_NO_LOCK_VAL), VERR_INVALID_PARAMETER);
    AssertCompile(sizeof(RTSEMEVENTINTERNAL) > sizeof(void *));

    PRTSEMEVENTINTERNAL pThis = (PRTSEMEVENTINTERNAL)RTMemAlloc(sizeof(*pThis));
    if (!pThis)
        return VERR_NO_MEMORY;

    pThis->u32Magic = RTSEMEVENT_MAGIC;
    KeInitializeEvent(&pThis->Event, SynchronizationEvent, FALSE);

    *phEventSem = pThis;
    return VINF_SUCCESS;
}


RTDECL(int)  RTSemEventDestroy(RTSEMEVENT hEventSem)
{
    /*
     * Validate input.
     */
    PRTSEMEVENTINTERNAL pThis = hEventSem;
    if (pThis == NIL_RTSEMEVENT)
        return VINF_SUCCESS;
    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
    AssertMsgReturn(pThis->u32Magic == RTSEMEVENT_MAGIC, ("pThis->u32Magic=%RX32 pThis=%p\n", pThis->u32Magic, pThis), VERR_INVALID_HANDLE);

    /*
     * Invalidate it and signal the object just in case.
     */
    ASMAtomicIncU32(&pThis->u32Magic);
    KeSetEvent(&pThis->Event, 0xfff, FALSE);
    RTMemFree(pThis);
    return VINF_SUCCESS;
}


RTDECL(int)  RTSemEventSignal(RTSEMEVENT hEventSem)
{
    /*
     * Validate input.
     */
    PRTSEMEVENTINTERNAL pThis = (PRTSEMEVENTINTERNAL)hEventSem;
    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
    AssertMsgReturn(pThis->u32Magic == RTSEMEVENT_MAGIC, ("pThis->u32Magic=%RX32 pThis=%p\n", pThis->u32Magic, pThis), VERR_INVALID_HANDLE);

    /*
     * Signal the event object.
     */
    KeSetEvent(&pThis->Event, 1, FALSE);
    return VINF_SUCCESS;
}


static int rtSemEventWait(RTSEMEVENT hEventSem, RTMSINTERVAL cMillies, bool fInterruptible)
{
    /*
     * Validate input.
     */
    PRTSEMEVENTINTERNAL pThis = (PRTSEMEVENTINTERNAL)hEventSem;
    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
    AssertMsgReturn(pThis->u32Magic == RTSEMEVENT_MAGIC, ("pThis->u32Magic=%RX32 pThis=%p\n", pThis->u32Magic, pThis), VERR_INVALID_HANDLE);

    /*
     * Wait for it.
     * We're assuming interruptible waits should happen at UserMode level.
     */
    NTSTATUS        rcNt;
    KPROCESSOR_MODE WaitMode   = fInterruptible ? UserMode : KernelMode;
    if (cMillies == RT_INDEFINITE_WAIT)
        rcNt = KeWaitForSingleObject(&pThis->Event, Executive, WaitMode, fInterruptible, NULL);
    else
    {
        LARGE_INTEGER Timeout;
        Timeout.QuadPart = -(int64_t)cMillies * 10000;
        rcNt = KeWaitForSingleObject(&pThis->Event, Executive, WaitMode, fInterruptible, &Timeout);
    }
    switch (rcNt)
    {
        case STATUS_SUCCESS:
            if (pThis->u32Magic == RTSEMEVENT_MAGIC)
                return VINF_SUCCESS;
            return VERR_SEM_DESTROYED;
        case STATUS_ALERTED:
            return VERR_INTERRUPTED;
        case STATUS_USER_APC:
            return VERR_INTERRUPTED;
        case STATUS_TIMEOUT:
            return VERR_TIMEOUT;
        default:
            AssertMsgFailed(("pThis->u32Magic=%RX32 pThis=%p: wait returned %lx!\n",
                             pThis->u32Magic, pThis, (long)rcNt));
            return VERR_INTERNAL_ERROR;
    }
}


RTDECL(int)  RTSemEventWait(RTSEMEVENT hEventSem, RTMSINTERVAL cMillies)
{
    return rtSemEventWait(hEventSem, cMillies, false /* fInterruptible */);
}


RTDECL(int)  RTSemEventWaitNoResume(RTSEMEVENT hEventSem, RTMSINTERVAL cMillies)
{
    return rtSemEventWait(hEventSem, cMillies, true /* fInterruptible */);
}

