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/* $Id: handletablesimple.cpp $ */
/** @file
* IPRT - Handle Tables.
*/
/*
* Copyright (C) 2008-2023 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
*/
/*********************************************************************************************************************************
* Header Files *
*********************************************************************************************************************************/
#include <iprt/handletable.h>
#include "internal/iprt.h"
#include <iprt/mem.h>
#include <iprt/spinlock.h>
#include <iprt/err.h>
#include <iprt/assert.h>
#include <iprt/param.h>
#include <iprt/string.h>
#include <iprt/asm.h>
#include "internal/magics.h"
#include "handletable.h"
RTDECL(int) RTHandleTableAlloc(RTHANDLETABLE hHandleTable, void *pvObj, uint32_t *ph)
{
/* validate the input */
PRTHANDLETABLEINT pThis = (PRTHANDLETABLEINT)hHandleTable;
AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
AssertReturn(pThis->u32Magic == RTHANDLETABLE_MAGIC, VERR_INVALID_HANDLE);
AssertReturn(!(pThis->fFlags & RTHANDLETABLE_FLAGS_CONTEXT), VERR_INVALID_FUNCTION);
AssertReturn(!RTHT_IS_FREE(pvObj), VERR_INVALID_PARAMETER);
AssertPtrReturn(ph, VERR_INVALID_POINTER);
*ph = pThis->uBase - 1;
/*
* Allocation loop.
*/
rtHandleTableLock(pThis);
int rc;
do
{
/*
* Try grab a free entry from the head of the free list.
*/
uint32_t i = pThis->iFreeHead;
if (i != NIL_RTHT_INDEX)
{
PRTHTENTRYFREE pFree = (PRTHTENTRYFREE)rtHandleTableLookupSimpleIdx(pThis, i);
Assert(pFree);
if (i == pThis->iFreeTail)
pThis->iFreeTail = pThis->iFreeHead = NIL_RTHT_INDEX;
else
pThis->iFreeHead = RTHT_GET_FREE_IDX(pFree);
pThis->cCurAllocated++;
Assert(pThis->cCurAllocated <= pThis->cCur);
/*
* Setup the entry and return.
*/
PRTHTENTRY pEntry = (PRTHTENTRY)pFree;
pEntry->pvObj = pvObj;
*ph = i + pThis->uBase;
rc = VINF_SUCCESS;
}
/*
* Must expand the handle table, unless it's full.
*/
else if (pThis->cCur >= pThis->cMax)
{
rc = VERR_NO_MORE_HANDLES;
Assert(pThis->cCur == pThis->cCurAllocated);
}
else
{
/*
* Do we have to expand the 1st level table too?
*/
uint32_t const iLevel1 = pThis->cCur / RTHT_LEVEL2_ENTRIES;
uint32_t cLevel1 = iLevel1 >= pThis->cLevel1
? pThis->cLevel1 + PAGE_SIZE / sizeof(void *)
: 0;
if (cLevel1 > pThis->cMax / RTHT_LEVEL2_ENTRIES)
cLevel1 = pThis->cMax / RTHT_LEVEL2_ENTRIES;
Assert(!cLevel1 || pThis->cMax / RTHT_LEVEL2_ENTRIES >= RTHT_LEVEL1_DYN_ALLOC_THRESHOLD);
/* leave the lock (never do fancy stuff from behind a spinlock). */
rtHandleTableUnlock(pThis);
/*
* Do the allocation(s).
*/
rc = VERR_TRY_AGAIN;
void **papvLevel1 = NULL;
if (cLevel1)
{
papvLevel1 = (void **)RTMemAlloc(sizeof(void *) * cLevel1);
if (!papvLevel1)
return VERR_NO_MEMORY;
}
PRTHTENTRY paTable = (PRTHTENTRY)RTMemAlloc(sizeof(*paTable) * RTHT_LEVEL2_ENTRIES);
if (!paTable)
{
RTMemFree(papvLevel1);
return VERR_NO_MEMORY;
}
/* re-enter the lock. */
rtHandleTableLock(pThis);
/*
* Insert the new bits, but be a bit careful as someone might have
* raced us expanding the table.
*/
/* deal with the 1st level lookup expansion first */
if (cLevel1)
{
Assert(papvLevel1);
if (cLevel1 > pThis->cLevel1)
{
/* Replace the 1st level table. */
memcpy(papvLevel1, pThis->papvLevel1, sizeof(void *) * pThis->cLevel1);
memset(&papvLevel1[pThis->cLevel1], 0, sizeof(void *) * (cLevel1 - pThis->cLevel1));
pThis->cLevel1 = cLevel1;
void **papvTmp = pThis->papvLevel1;
pThis->papvLevel1 = papvLevel1;
papvLevel1 = papvTmp;
}
/* free the obsolete one (outside the lock of course) */
rtHandleTableUnlock(pThis);
RTMemFree(papvLevel1);
rtHandleTableLock(pThis);
}
/* insert the table we allocated. */
uint32_t iLevel1New = pThis->cCur / RTHT_LEVEL2_ENTRIES;
if ( iLevel1New < pThis->cLevel1
&& pThis->cCur < pThis->cMax)
{
pThis->papvLevel1[iLevel1New] = paTable;
/* link all entries into a free list. */
Assert(!(pThis->cCur % RTHT_LEVEL2_ENTRIES));
for (i = 0; i < RTHT_LEVEL2_ENTRIES - 1; i++)
RTHT_SET_FREE_IDX((PRTHTENTRYFREE)&paTable[i], i + 1 + pThis->cCur);
RTHT_SET_FREE_IDX((PRTHTENTRYFREE)&paTable[RTHT_LEVEL2_ENTRIES - 1], NIL_RTHT_INDEX);
/* join the free list with the other. */
if (pThis->iFreeTail == NIL_RTHT_INDEX)
pThis->iFreeHead = pThis->cCur;
else
{
PRTHTENTRYFREE pPrev = (PRTHTENTRYFREE)rtHandleTableLookupSimpleIdx(pThis, pThis->iFreeTail);
Assert(pPrev);
RTHT_SET_FREE_IDX(pPrev, pThis->cCur);
}
pThis->iFreeTail = pThis->cCur + RTHT_LEVEL2_ENTRIES - 1;
pThis->cCur += RTHT_LEVEL2_ENTRIES;
}
else
{
/* free the table (raced someone, and we lost). */
rtHandleTableUnlock(pThis);
RTMemFree(paTable);
rtHandleTableLock(pThis);
}
rc = VERR_TRY_AGAIN;
}
} while (rc == VERR_TRY_AGAIN);
rtHandleTableUnlock(pThis);
return rc;
}
RT_EXPORT_SYMBOL(RTHandleTableAlloc);
RTDECL(void *) RTHandleTableLookup(RTHANDLETABLE hHandleTable, uint32_t h)
{
/* validate the input */
PRTHANDLETABLEINT pThis = (PRTHANDLETABLEINT)hHandleTable;
AssertPtrReturn(pThis, NULL);
AssertReturn(pThis->u32Magic == RTHANDLETABLE_MAGIC, NULL);
AssertReturn(!(pThis->fFlags & RTHANDLETABLE_FLAGS_CONTEXT), NULL);
void *pvObj = NULL;
/* acquire the lock */
rtHandleTableLock(pThis);
/*
* Perform the lookup and retaining.
*/
PRTHTENTRY pEntry = rtHandleTableLookupSimple(pThis, h);
if (pEntry)
{
pvObj = pEntry->pvObj;
if (!RTHT_IS_FREE(pvObj))
{
if (pThis->pfnRetain)
{
int rc = pThis->pfnRetain(hHandleTable, pEntry->pvObj, NULL, pThis->pvRetainUser);
if (RT_FAILURE(rc))
pvObj = NULL;
}
}
else
pvObj = NULL;
}
/* release the lock */
rtHandleTableUnlock(pThis);
return pvObj;
}
RT_EXPORT_SYMBOL(RTHandleTableLookup);
RTDECL(void *) RTHandleTableFree(RTHANDLETABLE hHandleTable, uint32_t h)
{
/* validate the input */
PRTHANDLETABLEINT pThis = (PRTHANDLETABLEINT)hHandleTable;
AssertPtrReturn(pThis, NULL);
AssertReturn(pThis->u32Magic == RTHANDLETABLE_MAGIC, NULL);
AssertReturn(!(pThis->fFlags & RTHANDLETABLE_FLAGS_CONTEXT), NULL);
void *pvObj = NULL;
/* acquire the lock */
rtHandleTableLock(pThis);
/*
* Perform the lookup and retaining.
*/
PRTHTENTRY pEntry = rtHandleTableLookupSimple(pThis, h);
if (pEntry)
{
pvObj = pEntry->pvObj;
if (!RTHT_IS_FREE(pvObj))
{
if (pThis->pfnRetain)
{
int rc = pThis->pfnRetain(hHandleTable, pEntry->pvObj, NULL, pThis->pvRetainUser);
if (RT_FAILURE(rc))
pvObj = NULL;
}
/*
* Link it into the free list.
*/
if (pvObj)
{
PRTHTENTRYFREE pFree = (PRTHTENTRYFREE)pEntry;
RTHT_SET_FREE_IDX(pFree, NIL_RTHT_INDEX);
uint32_t const i = h - pThis->uBase;
if (pThis->iFreeTail == NIL_RTHT_INDEX)
pThis->iFreeHead = pThis->iFreeTail = i;
else
{
PRTHTENTRYFREE pPrev = (PRTHTENTRYFREE)rtHandleTableLookupSimpleIdx(pThis, pThis->iFreeTail);
Assert(pPrev);
RTHT_SET_FREE_IDX(pPrev, i);
pThis->iFreeTail = i;
}
Assert(pThis->cCurAllocated > 0);
pThis->cCurAllocated--;
}
}
else
pvObj = NULL;
}
/* release the lock */
rtHandleTableUnlock(pThis);
return pvObj;
}
RT_EXPORT_SYMBOL(RTHandleTableFree);
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