1 | /* $Id: handletablesimple.cpp 98103 2023-01-17 14:15:46Z vboxsync $ */
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2 | /** @file
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3 | * IPRT - Handle Tables.
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4 | */
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5 |
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6 | /*
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7 | * Copyright (C) 2008-2023 Oracle and/or its affiliates.
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8 | *
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9 | * This file is part of VirtualBox base platform packages, as
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10 | * available from https://www.virtualbox.org.
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11 | *
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12 | * This program is free software; you can redistribute it and/or
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13 | * modify it under the terms of the GNU General Public License
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14 | * as published by the Free Software Foundation, in version 3 of the
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15 | * License.
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16 | *
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17 | * This program is distributed in the hope that it will be useful, but
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18 | * WITHOUT ANY WARRANTY; without even the implied warranty of
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19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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20 | * General Public License for more details.
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21 | *
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22 | * You should have received a copy of the GNU General Public License
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23 | * along with this program; if not, see <https://www.gnu.org/licenses>.
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24 | *
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25 | * The contents of this file may alternatively be used under the terms
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26 | * of the Common Development and Distribution License Version 1.0
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27 | * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
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28 | * in the VirtualBox distribution, in which case the provisions of the
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29 | * CDDL are applicable instead of those of the GPL.
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30 | *
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31 | * You may elect to license modified versions of this file under the
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32 | * terms and conditions of either the GPL or the CDDL or both.
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33 | *
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34 | * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
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35 | */
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36 |
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37 |
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38 | /*********************************************************************************************************************************
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39 | * Header Files *
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40 | *********************************************************************************************************************************/
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41 | #include <iprt/handletable.h>
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42 | #include "internal/iprt.h"
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43 |
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44 | #include <iprt/mem.h>
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45 | #include <iprt/spinlock.h>
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46 | #include <iprt/err.h>
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47 | #include <iprt/assert.h>
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48 | #include <iprt/param.h>
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49 | #include <iprt/string.h>
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50 | #include <iprt/asm.h>
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51 | #include "internal/magics.h"
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52 | #include "handletable.h"
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53 |
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54 |
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55 | RTDECL(int) RTHandleTableAlloc(RTHANDLETABLE hHandleTable, void *pvObj, uint32_t *ph)
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56 | {
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57 | /* validate the input */
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58 | PRTHANDLETABLEINT pThis = (PRTHANDLETABLEINT)hHandleTable;
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59 | AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
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60 | AssertReturn(pThis->u32Magic == RTHANDLETABLE_MAGIC, VERR_INVALID_HANDLE);
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61 | AssertReturn(!(pThis->fFlags & RTHANDLETABLE_FLAGS_CONTEXT), VERR_INVALID_FUNCTION);
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62 | AssertReturn(!RTHT_IS_FREE(pvObj), VERR_INVALID_PARAMETER);
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63 | AssertPtrReturn(ph, VERR_INVALID_POINTER);
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64 | *ph = pThis->uBase - 1;
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65 |
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66 | /*
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67 | * Allocation loop.
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68 | */
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69 | rtHandleTableLock(pThis);
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70 |
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71 | int rc;
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72 | do
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73 | {
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74 | /*
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75 | * Try grab a free entry from the head of the free list.
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76 | */
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77 | uint32_t i = pThis->iFreeHead;
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78 | if (i != NIL_RTHT_INDEX)
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79 | {
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80 | PRTHTENTRYFREE pFree = (PRTHTENTRYFREE)rtHandleTableLookupSimpleIdx(pThis, i);
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81 | Assert(pFree);
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82 | if (i == pThis->iFreeTail)
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83 | pThis->iFreeTail = pThis->iFreeHead = NIL_RTHT_INDEX;
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84 | else
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85 | pThis->iFreeHead = RTHT_GET_FREE_IDX(pFree);
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86 | pThis->cCurAllocated++;
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87 | Assert(pThis->cCurAllocated <= pThis->cCur);
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88 |
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89 | /*
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90 | * Setup the entry and return.
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91 | */
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92 | PRTHTENTRY pEntry = (PRTHTENTRY)pFree;
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93 | pEntry->pvObj = pvObj;
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94 | *ph = i + pThis->uBase;
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95 | rc = VINF_SUCCESS;
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96 | }
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97 | /*
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98 | * Must expand the handle table, unless it's full.
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99 | */
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100 | else if (pThis->cCur >= pThis->cMax)
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101 | {
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102 | rc = VERR_NO_MORE_HANDLES;
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103 | Assert(pThis->cCur == pThis->cCurAllocated);
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104 | }
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105 | else
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106 | {
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107 | /*
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108 | * Do we have to expand the 1st level table too?
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109 | */
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110 | uint32_t const iLevel1 = pThis->cCur / RTHT_LEVEL2_ENTRIES;
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111 | uint32_t cLevel1 = iLevel1 >= pThis->cLevel1
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112 | ? pThis->cLevel1 + PAGE_SIZE / sizeof(void *)
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113 | : 0;
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114 | if (cLevel1 > pThis->cMax / RTHT_LEVEL2_ENTRIES)
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115 | cLevel1 = pThis->cMax / RTHT_LEVEL2_ENTRIES;
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116 | Assert(!cLevel1 || pThis->cMax / RTHT_LEVEL2_ENTRIES >= RTHT_LEVEL1_DYN_ALLOC_THRESHOLD);
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117 |
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118 | /* leave the lock (never do fancy stuff from behind a spinlock). */
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119 | rtHandleTableUnlock(pThis);
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120 |
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121 | /*
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122 | * Do the allocation(s).
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123 | */
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124 | rc = VERR_TRY_AGAIN;
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125 | void **papvLevel1 = NULL;
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126 | if (cLevel1)
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127 | {
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128 | papvLevel1 = (void **)RTMemAlloc(sizeof(void *) * cLevel1);
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129 | if (!papvLevel1)
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130 | return VERR_NO_MEMORY;
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131 | }
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132 |
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133 | PRTHTENTRY paTable = (PRTHTENTRY)RTMemAlloc(sizeof(*paTable) * RTHT_LEVEL2_ENTRIES);
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134 | if (!paTable)
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135 | {
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136 | RTMemFree(papvLevel1);
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137 | return VERR_NO_MEMORY;
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138 | }
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139 |
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140 | /* re-enter the lock. */
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141 | rtHandleTableLock(pThis);
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142 |
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143 | /*
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144 | * Insert the new bits, but be a bit careful as someone might have
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145 | * raced us expanding the table.
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146 | */
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147 | /* deal with the 1st level lookup expansion first */
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148 | if (cLevel1)
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149 | {
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150 | Assert(papvLevel1);
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151 | if (cLevel1 > pThis->cLevel1)
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152 | {
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153 | /* Replace the 1st level table. */
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154 | memcpy(papvLevel1, pThis->papvLevel1, sizeof(void *) * pThis->cLevel1);
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155 | memset(&papvLevel1[pThis->cLevel1], 0, sizeof(void *) * (cLevel1 - pThis->cLevel1));
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156 | pThis->cLevel1 = cLevel1;
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157 | void **papvTmp = pThis->papvLevel1;
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158 | pThis->papvLevel1 = papvLevel1;
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159 | papvLevel1 = papvTmp;
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160 | }
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161 |
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162 | /* free the obsolete one (outside the lock of course) */
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163 | rtHandleTableUnlock(pThis);
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164 | RTMemFree(papvLevel1);
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165 | rtHandleTableLock(pThis);
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166 | }
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167 |
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168 | /* insert the table we allocated. */
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169 | uint32_t iLevel1New = pThis->cCur / RTHT_LEVEL2_ENTRIES;
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170 | if ( iLevel1New < pThis->cLevel1
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171 | && pThis->cCur < pThis->cMax)
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172 | {
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173 | pThis->papvLevel1[iLevel1New] = paTable;
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174 |
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175 | /* link all entries into a free list. */
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176 | Assert(!(pThis->cCur % RTHT_LEVEL2_ENTRIES));
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177 | for (i = 0; i < RTHT_LEVEL2_ENTRIES - 1; i++)
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178 | RTHT_SET_FREE_IDX((PRTHTENTRYFREE)&paTable[i], i + 1 + pThis->cCur);
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179 | RTHT_SET_FREE_IDX((PRTHTENTRYFREE)&paTable[RTHT_LEVEL2_ENTRIES - 1], NIL_RTHT_INDEX);
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180 |
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181 | /* join the free list with the other. */
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182 | if (pThis->iFreeTail == NIL_RTHT_INDEX)
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183 | pThis->iFreeHead = pThis->cCur;
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184 | else
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185 | {
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186 | PRTHTENTRYFREE pPrev = (PRTHTENTRYFREE)rtHandleTableLookupSimpleIdx(pThis, pThis->iFreeTail);
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187 | Assert(pPrev);
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188 | RTHT_SET_FREE_IDX(pPrev, pThis->cCur);
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189 | }
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190 | pThis->iFreeTail = pThis->cCur + RTHT_LEVEL2_ENTRIES - 1;
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191 |
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192 | pThis->cCur += RTHT_LEVEL2_ENTRIES;
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193 | }
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194 | else
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195 | {
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196 | /* free the table (raced someone, and we lost). */
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197 | rtHandleTableUnlock(pThis);
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198 | RTMemFree(paTable);
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199 | rtHandleTableLock(pThis);
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200 | }
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201 |
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202 | rc = VERR_TRY_AGAIN;
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203 | }
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204 | } while (rc == VERR_TRY_AGAIN);
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205 |
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206 | rtHandleTableUnlock(pThis);
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207 |
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208 | return rc;
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209 | }
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210 | RT_EXPORT_SYMBOL(RTHandleTableAlloc);
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211 |
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212 |
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213 | RTDECL(void *) RTHandleTableLookup(RTHANDLETABLE hHandleTable, uint32_t h)
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214 | {
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215 | /* validate the input */
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216 | PRTHANDLETABLEINT pThis = (PRTHANDLETABLEINT)hHandleTable;
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217 | AssertPtrReturn(pThis, NULL);
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218 | AssertReturn(pThis->u32Magic == RTHANDLETABLE_MAGIC, NULL);
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219 | AssertReturn(!(pThis->fFlags & RTHANDLETABLE_FLAGS_CONTEXT), NULL);
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220 |
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221 | void *pvObj = NULL;
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222 |
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223 | /* acquire the lock */
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224 | rtHandleTableLock(pThis);
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225 |
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226 | /*
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227 | * Perform the lookup and retaining.
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228 | */
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229 | PRTHTENTRY pEntry = rtHandleTableLookupSimple(pThis, h);
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230 | if (pEntry)
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231 | {
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232 | pvObj = pEntry->pvObj;
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233 | if (!RTHT_IS_FREE(pvObj))
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234 | {
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235 | if (pThis->pfnRetain)
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236 | {
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237 | int rc = pThis->pfnRetain(hHandleTable, pEntry->pvObj, NULL, pThis->pvRetainUser);
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238 | if (RT_FAILURE(rc))
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239 | pvObj = NULL;
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240 | }
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241 | }
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242 | else
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243 | pvObj = NULL;
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244 | }
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245 |
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246 | /* release the lock */
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247 | rtHandleTableUnlock(pThis);
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248 | return pvObj;
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249 | }
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250 | RT_EXPORT_SYMBOL(RTHandleTableLookup);
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251 |
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252 |
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253 | RTDECL(void *) RTHandleTableFree(RTHANDLETABLE hHandleTable, uint32_t h)
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254 | {
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255 | /* validate the input */
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256 | PRTHANDLETABLEINT pThis = (PRTHANDLETABLEINT)hHandleTable;
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257 | AssertPtrReturn(pThis, NULL);
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258 | AssertReturn(pThis->u32Magic == RTHANDLETABLE_MAGIC, NULL);
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259 | AssertReturn(!(pThis->fFlags & RTHANDLETABLE_FLAGS_CONTEXT), NULL);
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260 |
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261 | void *pvObj = NULL;
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262 |
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263 | /* acquire the lock */
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264 | rtHandleTableLock(pThis);
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265 |
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266 | /*
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267 | * Perform the lookup and retaining.
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268 | */
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269 | PRTHTENTRY pEntry = rtHandleTableLookupSimple(pThis, h);
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270 | if (pEntry)
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271 | {
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272 | pvObj = pEntry->pvObj;
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273 | if (!RTHT_IS_FREE(pvObj))
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274 | {
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275 | if (pThis->pfnRetain)
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276 | {
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277 | int rc = pThis->pfnRetain(hHandleTable, pEntry->pvObj, NULL, pThis->pvRetainUser);
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278 | if (RT_FAILURE(rc))
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279 | pvObj = NULL;
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280 | }
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281 |
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282 | /*
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283 | * Link it into the free list.
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284 | */
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285 | if (pvObj)
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286 | {
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287 | PRTHTENTRYFREE pFree = (PRTHTENTRYFREE)pEntry;
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288 | RTHT_SET_FREE_IDX(pFree, NIL_RTHT_INDEX);
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289 |
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290 | uint32_t const i = h - pThis->uBase;
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291 | if (pThis->iFreeTail == NIL_RTHT_INDEX)
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292 | pThis->iFreeHead = pThis->iFreeTail = i;
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293 | else
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294 | {
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295 | PRTHTENTRYFREE pPrev = (PRTHTENTRYFREE)rtHandleTableLookupSimpleIdx(pThis, pThis->iFreeTail);
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296 | Assert(pPrev);
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297 | RTHT_SET_FREE_IDX(pPrev, i);
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298 | pThis->iFreeTail = i;
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299 | }
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300 |
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301 | Assert(pThis->cCurAllocated > 0);
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302 | pThis->cCurAllocated--;
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303 | }
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304 | }
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305 | else
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306 | pvObj = NULL;
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307 | }
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308 |
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309 | /* release the lock */
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310 | rtHandleTableUnlock(pThis);
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311 | return pvObj;
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312 | }
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313 | RT_EXPORT_SYMBOL(RTHandleTableFree);
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314 |
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