handletablesimple.cpp@ 69111

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1	/* $Id: handletablesimple.cpp 69111 2017-10-17 14:26:02Z vboxsync $ */
2	/** @file
3	* IPRT - Handle Tables.
4	*/
5
6	/*
7	* Copyright (C) 2008-2017 Oracle Corporation
8	*
9	* This file is part of VirtualBox Open Source Edition (OSE), as
10	* available from http://www.virtualbox.org. This file is free software;
11	* you can redistribute it and/or modify it under the terms of the GNU
12	* General Public License (GPL) as published by the Free Software
13	* Foundation, in version 2 as it comes in the "COPYING" file of the
14	* VirtualBox OSE distribution. VirtualBox OSE is distributed in the
15	* hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
16	*
17	* The contents of this file may alternatively be used under the terms
18	* of the Common Development and Distribution License Version 1.0
19	* (CDDL) only, as it comes in the "COPYING.CDDL" file of the
20	* VirtualBox OSE distribution, in which case the provisions of the
21	* CDDL are applicable instead of those of the GPL.
22	*
23	* You may elect to license modified versions of this file under the
24	* terms and conditions of either the GPL or the CDDL or both.
25	*/
26
27
28	/*********************************************************************************************************************************
29	* Header Files *
30	*********************************************************************************************************************************/
31	#include <iprt/handletable.h>
32	#include "internal/iprt.h"
33
34	#include <iprt/mem.h>
35	#include <iprt/spinlock.h>
36	#include <iprt/err.h>
37	#include <iprt/assert.h>
38	#include <iprt/param.h>
39	#include <iprt/string.h>
40	#include <iprt/asm.h>
41	#include "internal/magics.h"
42	#include "handletable.h"
43
44
45	RTDECL(int) RTHandleTableAlloc(RTHANDLETABLE hHandleTable, void pvObj, uint32_t ph)
46	{
47	/* validate the input */
48	PRTHANDLETABLEINT pThis = (PRTHANDLETABLEINT)hHandleTable;
49	AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
50	AssertReturn(pThis->u32Magic == RTHANDLETABLE_MAGIC, VERR_INVALID_HANDLE);
51	AssertReturn(!(pThis->fFlags & RTHANDLETABLE_FLAGS_CONTEXT), VERR_INVALID_FUNCTION);
52	AssertReturn(!RTHT_IS_FREE(pvObj), VERR_INVALID_PARAMETER);
53	AssertPtrReturn(ph, VERR_INVALID_POINTER);
54	*ph = pThis->uBase - 1;
55
56	/*
57	* Allocation loop.
58	*/
59	rtHandleTableLock(pThis);
60
61	int rc;
62	do
63	{
64	/*
65	* Try grab a free entry from the head of the free list.
66	*/
67	uint32_t i = pThis->iFreeHead;
68	if (i != NIL_RTHT_INDEX)
69	{
70	PRTHTENTRYFREE pFree = (PRTHTENTRYFREE)rtHandleTableLookupSimpleIdx(pThis, i);
71	Assert(pFree);
72	if (i == pThis->iFreeTail)
73	pThis->iFreeTail = pThis->iFreeHead = NIL_RTHT_INDEX;
74	else
75	pThis->iFreeHead = RTHT_GET_FREE_IDX(pFree);
76	pThis->cCurAllocated++;
77	Assert(pThis->cCurAllocated <= pThis->cCur);
78
79	/*
80	* Setup the entry and return.
81	*/
82	PRTHTENTRY pEntry = (PRTHTENTRY)pFree;
83	pEntry->pvObj = pvObj;
84	*ph = i + pThis->uBase;
85	rc = VINF_SUCCESS;
86	}
87	/*
88	* Must expand the handle table, unless it's full.
89	*/
90	else if (pThis->cCur >= pThis->cMax)
91	{
92	rc = VERR_NO_MORE_HANDLES;
93	Assert(pThis->cCur == pThis->cCurAllocated);
94	}
95	else
96	{
97	/*
98	* Do we have to expand the 1st level table too?
99	*/
100	uint32_t const iLevel1 = pThis->cCur / RTHT_LEVEL2_ENTRIES;
101	uint32_t cLevel1 = iLevel1 >= pThis->cLevel1
102	? pThis->cLevel1 + PAGE_SIZE / sizeof(void *)
103	: 0;
104	if (cLevel1 > pThis->cMax / RTHT_LEVEL2_ENTRIES)
105	cLevel1 = pThis->cMax / RTHT_LEVEL2_ENTRIES;
106	Assert(!cLevel1 \|\| pThis->cMax / RTHT_LEVEL2_ENTRIES >= RTHT_LEVEL1_DYN_ALLOC_THRESHOLD);
107
108	/* leave the lock (never do fancy stuff from behind a spinlock). */
109	rtHandleTableUnlock(pThis);
110
111	/*
112	* Do the allocation(s).
113	*/
114	rc = VERR_TRY_AGAIN;
115	void **papvLevel1 = NULL;
116	if (cLevel1)
117	{
118	papvLevel1 = (void *)RTMemAlloc(sizeof(void ) * cLevel1);
119	if (!papvLevel1)
120	return VERR_NO_MEMORY;
121	}
122
123	PRTHTENTRY paTable = (PRTHTENTRY)RTMemAlloc(sizeof(paTable) RTHT_LEVEL2_ENTRIES);
124	if (!paTable)
125	{
126	RTMemFree(papvLevel1);
127	return VERR_NO_MEMORY;
128	}
129
130	/* re-enter the lock. */
131	rtHandleTableLock(pThis);
132
133	/*
134	* Insert the new bits, but be a bit careful as someone might have
135	* raced us expanding the table.
136	*/
137	/* deal with the 1st level lookup expansion first */
138	if (cLevel1)
139	{
140	Assert(papvLevel1);
141	if (cLevel1 > pThis->cLevel1)
142	{
143	/* Replace the 1st level table. */
144	memcpy(papvLevel1, pThis->papvLevel1, sizeof(void ) pThis->cLevel1);
145	memset(&papvLevel1[pThis->cLevel1], 0, sizeof(void ) (cLevel1 - pThis->cLevel1));
146	pThis->cLevel1 = cLevel1;
147	void **papvTmp = pThis->papvLevel1;
148	pThis->papvLevel1 = papvLevel1;
149	papvLevel1 = papvTmp;
150	}
151
152	/* free the obsolete one (outside the lock of course) */
153	rtHandleTableUnlock(pThis);
154	RTMemFree(papvLevel1);
155	rtHandleTableLock(pThis);
156	}
157
158	/* insert the table we allocated. */
159	uint32_t iLevel1New = pThis->cCur / RTHT_LEVEL2_ENTRIES;
160	if ( iLevel1New < pThis->cLevel1
161	&& pThis->cCur < pThis->cMax)
162	{
163	pThis->papvLevel1[iLevel1New] = paTable;
164
165	/* link all entries into a free list. */
166	Assert(!(pThis->cCur % RTHT_LEVEL2_ENTRIES));
167	for (i = 0; i < RTHT_LEVEL2_ENTRIES - 1; i++)
168	RTHT_SET_FREE_IDX((PRTHTENTRYFREE)&paTable[i], i + 1 + pThis->cCur);
169	RTHT_SET_FREE_IDX((PRTHTENTRYFREE)&paTable[RTHT_LEVEL2_ENTRIES - 1], NIL_RTHT_INDEX);
170
171	/* join the free list with the other. */
172	if (pThis->iFreeTail == NIL_RTHT_INDEX)
173	pThis->iFreeHead = pThis->cCur;
174	else
175	{
176	PRTHTENTRYFREE pPrev = (PRTHTENTRYFREE)rtHandleTableLookupSimpleIdx(pThis, pThis->iFreeTail);
177	Assert(pPrev);
178	RTHT_SET_FREE_IDX(pPrev, pThis->cCur);
179	}
180	pThis->iFreeTail = pThis->cCur + RTHT_LEVEL2_ENTRIES - 1;
181
182	pThis->cCur += RTHT_LEVEL2_ENTRIES;
183	}
184	else
185	{
186	/* free the table (raced someone, and we lost). */
187	rtHandleTableUnlock(pThis);
188	RTMemFree(paTable);
189	rtHandleTableLock(pThis);
190	}
191
192	rc = VERR_TRY_AGAIN;
193	}
194	} while (rc == VERR_TRY_AGAIN);
195
196	rtHandleTableUnlock(pThis);
197
198	return rc;
199	}
200	RT_EXPORT_SYMBOL(RTHandleTableAlloc);
201
202
203	RTDECL(void *) RTHandleTableLookup(RTHANDLETABLE hHandleTable, uint32_t h)
204	{
205	/* validate the input */
206	PRTHANDLETABLEINT pThis = (PRTHANDLETABLEINT)hHandleTable;
207	AssertPtrReturn(pThis, NULL);
208	AssertReturn(pThis->u32Magic == RTHANDLETABLE_MAGIC, NULL);
209	AssertReturn(!(pThis->fFlags & RTHANDLETABLE_FLAGS_CONTEXT), NULL);
210
211	void *pvObj = NULL;
212
213	/* acquire the lock */
214	rtHandleTableLock(pThis);
215
216	/*
217	* Perform the lookup and retaining.
218	*/
219	PRTHTENTRY pEntry = rtHandleTableLookupSimple(pThis, h);
220	if (pEntry)
221	{
222	pvObj = pEntry->pvObj;
223	if (!RTHT_IS_FREE(pvObj))
224	{
225	if (pThis->pfnRetain)
226	{
227	int rc = pThis->pfnRetain(hHandleTable, pEntry->pvObj, NULL, pThis->pvRetainUser);
228	if (RT_FAILURE(rc))
229	pvObj = NULL;
230	}
231	}
232	else
233	pvObj = NULL;
234	}
235
236	/* release the lock */
237	rtHandleTableUnlock(pThis);
238	return pvObj;
239	}
240	RT_EXPORT_SYMBOL(RTHandleTableLookup);
241
242
243	RTDECL(void *) RTHandleTableFree(RTHANDLETABLE hHandleTable, uint32_t h)
244	{
245	/* validate the input */
246	PRTHANDLETABLEINT pThis = (PRTHANDLETABLEINT)hHandleTable;
247	AssertPtrReturn(pThis, NULL);
248	AssertReturn(pThis->u32Magic == RTHANDLETABLE_MAGIC, NULL);
249	AssertReturn(!(pThis->fFlags & RTHANDLETABLE_FLAGS_CONTEXT), NULL);
250
251	void *pvObj = NULL;
252
253	/* acquire the lock */
254	rtHandleTableLock(pThis);
255
256	/*
257	* Perform the lookup and retaining.
258	*/
259	PRTHTENTRY pEntry = rtHandleTableLookupSimple(pThis, h);
260	if (pEntry)
261	{
262	pvObj = pEntry->pvObj;
263	if (!RTHT_IS_FREE(pvObj))
264	{
265	if (pThis->pfnRetain)
266	{
267	int rc = pThis->pfnRetain(hHandleTable, pEntry->pvObj, NULL, pThis->pvRetainUser);
268	if (RT_FAILURE(rc))
269	pvObj = NULL;
270	}
271
272	/*
273	* Link it into the free list.
274	*/
275	if (pvObj)
276	{
277	PRTHTENTRYFREE pFree = (PRTHTENTRYFREE)pEntry;
278	RTHT_SET_FREE_IDX(pFree, NIL_RTHT_INDEX);
279
280	uint32_t const i = h - pThis->uBase;
281	if (pThis->iFreeTail == NIL_RTHT_INDEX)
282	pThis->iFreeHead = pThis->iFreeTail = i;
283	else
284	{
285	PRTHTENTRYFREE pPrev = (PRTHTENTRYFREE)rtHandleTableLookupSimpleIdx(pThis, pThis->iFreeTail);
286	Assert(pPrev);
287	RTHT_SET_FREE_IDX(pPrev, i);
288	pThis->iFreeTail = i;
289	}
290
291	Assert(pThis->cCurAllocated > 0);
292	pThis->cCurAllocated--;
293	}
294	}
295	else
296	pvObj = NULL;
297	}
298
299	/* release the lock */
300	rtHandleTableUnlock(pThis);
301	return pvObj;
302	}
303	RT_EXPORT_SYMBOL(RTHandleTableFree);
304

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source: vbox/trunk/src/VBox/Runtime/common/misc/handletablesimple.cpp@ 69111

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