vfsmemory.cpp@ 74525

Last change on this file since 74525 was 73097, checked in by vboxsync, 6 years ago
*: Made RT_UOFFSETOF, RT_OFFSETOF, RT_UOFFSETOF_ADD and RT_OFFSETOF_ADD work like builtin_offsetof() and require compile time resolvable requests, adding RT_UOFFSETOF_DYN for the dynamic questions that can only be answered at runtime.
Property svn:eol-style set to `native` Property svn:keywords set to `Author Date Id Revision`
File size: 28.8 KB

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1	/* $Id: vfsmemory.cpp 73097 2018-07-12 21:06:33Z vboxsync $ */
2	/** @file
3	* IPRT - Virtual File System, Memory Backed VFS.
4	*/
5
6	/*
7	* Copyright (C) 2010-2017 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 "internal/iprt.h"
32	#include <iprt/vfs.h>
33
34	#include <iprt/asm.h>
35	#include <iprt/assert.h>
36	#include <iprt/err.h>
37	#include <iprt/file.h>
38	#include <iprt/list.h>
39	#include <iprt/poll.h>
40	#include <iprt/string.h>
41	#include <iprt/vfslowlevel.h>
42
43
44
45	/*********************************************************************************************************************************
46	* Header Files *
47	*********************************************************************************************************************************/
48	#include "internal/iprt.h"
49	#include <iprt/vfs.h>
50
51	#include <iprt/err.h>
52	#include <iprt/mem.h>
53
54
55	/*********************************************************************************************************************************
56	* Defined Constants And Macros *
57	*********************************************************************************************************************************/
58	/** The max extent size. */
59	#define RTVFSMEM_MAX_EXTENT_SIZE _2M
60
61
62	/*********************************************************************************************************************************
63	* Structures and Typedefs *
64	*********************************************************************************************************************************/
65
66	/**
67	* Memory base object info.
68	*/
69	typedef struct RTVFSMEMBASE
70	{
71	/** The basic object info. */
72	RTFSOBJINFO ObjInfo;
73	} RTVFSMEMBASE;
74
75
76	/**
77	* Memory file extent.
78	*
79	* This stores part of the file content.
80	*/
81	typedef struct RTVFSMEMEXTENT
82	{
83	/** Extent list entry. */
84	RTLISTNODE Entry;
85	/** The offset of this extent within the file. */
86	uint64_t off;
87	/** The size of the this extent. */
88	uint32_t cb;
89	/** The data. */
90	uint8_t abData[1];
91	} RTVFSMEMEXTENT;
92	/** Pointer to a memory file extent. */
93	typedef RTVFSMEMEXTENT *PRTVFSMEMEXTENT;
94
95	/**
96	* Memory file.
97	*/
98	typedef struct RTVFSMEMFILE
99	{
100	/** The base info. */
101	RTVFSMEMBASE Base;
102	/** The current file position. */
103	uint64_t offCurPos;
104	/** Pointer to the current file extent. */
105	PRTVFSMEMEXTENT pCurExt;
106	/** Linked list of file extents - RTVFSMEMEXTENT. */
107	RTLISTANCHOR ExtentHead;
108	/** The current extent size.
109	* This is slowly grown to RTVFSMEM_MAX_EXTENT_SIZE as the file grows. */
110	uint32_t cbExtent;
111	} RTVFSMEMFILE;
112	/** Pointer to a memory file. */
113	typedef RTVFSMEMFILE *PRTVFSMEMFILE;
114
115
116
117	/**
118	* @interface_method_impl{RTVFSOBJOPS,pfnClose}
119	*/
120	static DECLCALLBACK(int) rtVfsMemFile_Close(void *pvThis)
121	{
122	PRTVFSMEMFILE pThis = (PRTVFSMEMFILE)pvThis;
123
124	/*
125	* Free the extent list.
126	*/
127	PRTVFSMEMEXTENT pCur, pNext;
128	RTListForEachSafe(&pThis->ExtentHead, pCur, pNext, RTVFSMEMEXTENT, Entry)
129	{
130	pCur->off = RTFOFF_MAX;
131	pCur->cb = UINT32_MAX;
132	RTListNodeRemove(&pCur->Entry);
133	RTMemFree(pCur);
134	}
135	pThis->pCurExt = NULL;
136
137	return VINF_SUCCESS;
138	}
139
140
141	/**
142	* @interface_method_impl{RTVFSOBJOPS,pfnQueryInfo}
143	*/
144	static DECLCALLBACK(int) rtVfsMemFile_QueryInfo(void *pvThis, PRTFSOBJINFO pObjInfo, RTFSOBJATTRADD enmAddAttr)
145	{
146	PRTVFSMEMFILE pThis = (PRTVFSMEMFILE)pvThis;
147	switch (enmAddAttr)
148	{
149	case RTFSOBJATTRADD_NOTHING:
150	case RTFSOBJATTRADD_UNIX:
151	*pObjInfo = pThis->Base.ObjInfo;
152	return VINF_SUCCESS;
153
154	default:
155	return VERR_NOT_SUPPORTED;
156	}
157	}
158
159
160	/**
161	* The slow paths of rtVfsMemFile_LocateExtent.
162	*
163	* @copydoc rtVfsMemFile_LocateExtent
164	*/
165	static PRTVFSMEMEXTENT rtVfsMemFile_LocateExtentSlow(PRTVFSMEMFILE pThis, uint64_t off, bool *pfHit)
166	{
167	/*
168	* Search from the start or the previously used extent. The heuristics
169	* are very very simple, but whatever.
170	*/
171	PRTVFSMEMEXTENT pExtent = pThis->pCurExt;
172	if (!pExtent \|\| off < pExtent->off)
173	{
174	/* Consider the last entry first (for writes). */
175	pExtent = RTListGetLast(&pThis->ExtentHead, RTVFSMEMEXTENT, Entry);
176	if (!pExtent)
177	{
178	*pfHit = false;
179	return NULL;
180	}
181	if (off - pExtent->off < pExtent->cb)
182	{
183	*pfHit = true;
184	pThis->pCurExt = pExtent;
185	return pExtent;
186	}
187
188	/* Otherwise, start from the head. */
189	pExtent = RTListGetFirst(&pThis->ExtentHead, RTVFSMEMEXTENT, Entry);
190	}
191
192	while (off - pExtent->off >= pExtent->cb)
193	{
194	Assert(pExtent->off <= off);
195	PRTVFSMEMEXTENT pNext = RTListGetNext(&pThis->ExtentHead, pExtent, RTVFSMEMEXTENT, Entry);
196	if ( !pNext
197	\|\| pNext->off > off)
198	{
199	*pfHit = false;
200	return pNext;
201	}
202
203	pExtent = pNext;
204	}
205
206	*pfHit = true;
207	pThis->pCurExt = pExtent;
208	return pExtent;
209	}
210
211
212	/**
213	* Locates the extent covering the specified offset, or the one after it.
214	*
215	* @returns The closest extent. NULL if off is 0 and there are no extent
216	* covering byte 0 yet.
217	* @param pThis The memory file.
218	* @param off The offset (0-positive).
219	* @param pfHit Where to indicate whether the extent is a
220	* direct hit (@c true) or just a closest match
221	* (@c false).
222	*/
223	DECLINLINE(PRTVFSMEMEXTENT) rtVfsMemFile_LocateExtent(PRTVFSMEMFILE pThis, uint64_t off, bool *pfHit)
224	{
225	/*
226	* The most likely case is that we're hitting the extent we used in the
227	* previous access or the one immediately following it.
228	*/
229	PRTVFSMEMEXTENT pExtent = pThis->pCurExt;
230	if (!pExtent)
231	return rtVfsMemFile_LocateExtentSlow(pThis, off, pfHit);
232
233	if (off - pExtent->off >= pExtent->cb)
234	{
235	pExtent = RTListGetNext(&pThis->ExtentHead, pExtent, RTVFSMEMEXTENT, Entry);
236	if ( !pExtent
237	\|\| off - pExtent->off >= pExtent->cb)
238	return rtVfsMemFile_LocateExtentSlow(pThis, off, pfHit);
239	pThis->pCurExt = pExtent;
240	}
241
242	*pfHit = true;
243	return pExtent;
244	}
245
246
247	/**
248	* @interface_method_impl{RTVFSIOSTREAMOPS,pfnRead}
249	*/
250	static DECLCALLBACK(int) rtVfsMemFile_Read(void pvThis, RTFOFF off, PCRTSGBUF pSgBuf, bool fBlocking, size_t pcbRead)
251	{
252	PRTVFSMEMFILE pThis = (PRTVFSMEMFILE)pvThis;
253
254	Assert(pSgBuf->cSegs == 1);
255	NOREF(fBlocking);
256
257	/*
258	* Find the current position and check if it's within the file.
259	*/
260	uint64_t offUnsigned = off < 0 ? pThis->offCurPos : (uint64_t)off;
261	if (offUnsigned >= (uint64_t)pThis->Base.ObjInfo.cbObject)
262	{
263	if (pcbRead)
264	{
265	*pcbRead = 0;
266	pThis->offCurPos = offUnsigned;
267	return VINF_EOF;
268	}
269	return VERR_EOF;
270	}
271
272	size_t cbLeftToRead;
273	if (offUnsigned + pSgBuf->paSegs[0].cbSeg > (uint64_t)pThis->Base.ObjInfo.cbObject)
274	{
275	if (!pcbRead)
276	return VERR_EOF;
277	*pcbRead = cbLeftToRead = (size_t)((uint64_t)pThis->Base.ObjInfo.cbObject - offUnsigned);
278	}
279	else
280	{
281	cbLeftToRead = pSgBuf->paSegs[0].cbSeg;
282	if (pcbRead)
283	*pcbRead = cbLeftToRead;
284	}
285
286	/*
287	* Ok, we've got a valid stretch within the file. Do the reading.
288	*/
289	if (cbLeftToRead > 0)
290	{
291	uint8_t pbDst = (uint8_t )pSgBuf->paSegs[0].pvSeg;
292	bool fHit;
293	PRTVFSMEMEXTENT pExtent = rtVfsMemFile_LocateExtent(pThis, offUnsigned, &fHit);
294	for (;;)
295	{
296	size_t cbThisRead;
297
298	/*
299	* Do we hit an extent covering the current file surface?
300	*/
301	if (fHit)
302	{
303	/* Yes, copy the data. */
304	Assert(offUnsigned - pExtent->off < pExtent->cb);
305	size_t const offExtent = (size_t)(offUnsigned - pExtent->off);
306	cbThisRead = pExtent->cb - offExtent;
307	if (cbThisRead >= cbLeftToRead)
308	cbThisRead = cbLeftToRead;
309
310	memcpy(pbDst, &pExtent->abData[offUnsigned - pExtent->off], cbThisRead);
311
312	offUnsigned += cbThisRead;
313	cbLeftToRead -= cbThisRead;
314	if (!cbLeftToRead)
315	break;
316	pbDst += cbThisRead;
317
318	/* Advance, looping immediately if not sparse. */
319	PRTVFSMEMEXTENT pNext = RTListGetNext(&pThis->ExtentHead, pExtent, RTVFSMEMEXTENT, Entry);
320	if ( pNext
321	&& pNext->off == pExtent->off + pExtent->cb)
322	{
323	pExtent = pNext;
324	continue;
325	}
326
327	Assert(!pNext \|\| pNext->off > pExtent->off);
328	pExtent = pNext;
329	fHit = false;
330	}
331	else
332	Assert(!pExtent \|\| pExtent->off > offUnsigned);
333
334	/*
335	* No extent of this portion (sparse file) - Read zeros.
336	*/
337	if ( !pExtent
338	\|\| offUnsigned + cbLeftToRead <= pExtent->off)
339	cbThisRead = cbLeftToRead;
340	else
341	cbThisRead = (size_t)(pExtent->off - offUnsigned);
342
343	RT_BZERO(pbDst, cbThisRead);
344
345	offUnsigned += cbThisRead;
346	cbLeftToRead -= cbThisRead;
347	if (!cbLeftToRead)
348	break;
349	pbDst += cbThisRead;
350
351	/* Go on and read content from the next extent. */
352	fHit = true;
353	}
354	}
355
356	pThis->offCurPos = offUnsigned;
357	return VINF_SUCCESS;
358	}
359
360
361	/**
362	* Allocates a new extent covering the ground at @a offUnsigned.
363	*
364	* @returns Pointer to the new extent on success, NULL if we're out of memory.
365	* @param pThis The memory file.
366	* @param offUnsigned The location to allocate the extent at.
367	* @param cbToWrite The number of bytes we're interested in writing
368	* starting at @a offUnsigned.
369	* @param pNext The extention after @a offUnsigned. NULL if
370	* none, i.e. we're allocating space at the end of
371	* the file.
372	*/
373	static PRTVFSMEMEXTENT rtVfsMemFile_AllocExtent(PRTVFSMEMFILE pThis, uint64_t offUnsigned, size_t cbToWrite,
374	PRTVFSMEMEXTENT pNext)
375	{
376	/*
377	* Adjust the extent size if we haven't reached the max size yet.
378	*/
379	if (pThis->cbExtent != RTVFSMEM_MAX_EXTENT_SIZE)
380	{
381	if (cbToWrite >= RTVFSMEM_MAX_EXTENT_SIZE)
382	pThis->cbExtent = RTVFSMEM_MAX_EXTENT_SIZE;
383	else if (!RTListIsEmpty(&pThis->ExtentHead))
384	{
385	uint32_t cbNextExtent = pThis->cbExtent;
386	if (RT_IS_POWER_OF_TWO(cbNextExtent))
387	cbNextExtent *= 2;
388	else
389	{
390	/* Make it a power of two (seeRTVfsMemorizeIoStreamAsFile). */
391	cbNextExtent = _4K;
392	while (cbNextExtent < pThis->cbExtent)
393	cbNextExtent *= 2;
394	}
395	if (((pThis->Base.ObjInfo.cbAllocated + cbNextExtent) & (cbNextExtent - 1)) == 0)
396	pThis->cbExtent = cbNextExtent;
397	}
398	}
399
400	/*
401	* Figure out the size and position of the extent we're adding.
402	*/
403	uint64_t offExtent = offUnsigned & ~(uint64_t)(pThis->cbExtent - 1);
404	uint32_t cbExtent = pThis->cbExtent;
405
406	PRTVFSMEMEXTENT pPrev = pNext
407	? RTListGetPrev(&pThis->ExtentHead, pNext, RTVFSMEMEXTENT, Entry)
408	: RTListGetLast(&pThis->ExtentHead, RTVFSMEMEXTENT, Entry);
409	uint64_t const offPrev = pPrev ? pPrev->off + pPrev->cb : 0;
410	if (offExtent < offPrev)
411	offExtent = offPrev;
412
413	if (pNext)
414	{
415	uint64_t cbMaxExtent = pNext->off - offExtent;
416	if (cbMaxExtent < cbExtent)
417	cbExtent = (uint32_t)cbMaxExtent;
418	}
419
420	/*
421	* Allocate, initialize and insert the new extent.
422	*/
423	PRTVFSMEMEXTENT pNew = (PRTVFSMEMEXTENT)RTMemAllocZ(RT_UOFFSETOF_DYN(RTVFSMEMEXTENT, abData[cbExtent]));
424	if (pNew)
425	{
426	pNew->off = offExtent;
427	pNew->cb = cbExtent;
428	if (pPrev)
429	RTListNodeInsertAfter(&pPrev->Entry, &pNew->Entry);
430	else
431	RTListPrepend(&pThis->ExtentHead, &pNew->Entry);
432
433	pThis->Base.ObjInfo.cbAllocated += cbExtent;
434	}
435	/** @todo retry with minimum size. */
436
437	return pNew;
438	}
439
440
441	/**
442	* @interface_method_impl{RTVFSIOSTREAMOPS,pfnWrite}
443	*/
444	static DECLCALLBACK(int) rtVfsMemFile_Write(void pvThis, RTFOFF off, PCRTSGBUF pSgBuf, bool fBlocking, size_t pcbWritten)
445	{
446	PRTVFSMEMFILE pThis = (PRTVFSMEMFILE)pvThis;
447
448	Assert(pSgBuf->cSegs == 1);
449	NOREF(fBlocking);
450
451	/*
452	* Validate the write and set up the write loop.
453	*/
454	size_t cbLeftToWrite = pSgBuf->paSegs[0].cbSeg;
455	if (!cbLeftToWrite)
456	return VINF_SUCCESS; /* pcbWritten is already 0. */
457	uint64_t offUnsigned = off < 0 ? pThis->offCurPos : (uint64_t)off;
458	if (offUnsigned + cbLeftToWrite >= (uint64_t)RTFOFF_MAX)
459	return VERR_OUT_OF_RANGE;
460
461	int rc = VINF_SUCCESS;
462	uint8_t const pbSrc = (uint8_t const )pSgBuf->paSegs[0].pvSeg;
463	bool fHit;
464	PRTVFSMEMEXTENT pExtent = rtVfsMemFile_LocateExtent(pThis, offUnsigned, &fHit);
465	for (;;)
466	{
467	/*
468	* If we didn't hit an extent, allocate one (unless it's all zeros).
469	*/
470	if (!fHit)
471	{
472	Assert(!pExtent \|\| pExtent->off > offUnsigned);
473
474	/* Skip leading zeros if there is a whole bunch of them. */
475	uint8_t const pbSrcNZ = (uint8_t const )ASMMemFirstNonZero(pbSrc, cbLeftToWrite);
476	size_t cbZeros = pbSrcNZ ? pbSrcNZ - pbSrc : cbLeftToWrite;
477	if (cbZeros)
478	{
479	uint64_t const cbToNext = pExtent ? pExtent->off - offUnsigned : UINT64_MAX;
480	if (cbZeros > cbToNext)
481	cbZeros = (size_t)cbToNext;
482	offUnsigned += cbZeros;
483	cbLeftToWrite -= cbZeros;
484	if (!cbLeftToWrite)
485	break;
486
487	Assert(!pExtent \|\| offUnsigned <= pExtent->off);
488	if (pExtent && pExtent->off == offUnsigned)
489	{
490	fHit = true;
491	continue;
492	}
493	}
494
495	fHit = true;
496	pExtent = rtVfsMemFile_AllocExtent(pThis, offUnsigned, cbLeftToWrite, pExtent);
497	if (!pExtent)
498	{
499	rc = VERR_NO_MEMORY;
500	break;
501	}
502	}
503	Assert(offUnsigned - pExtent->off < pExtent->cb);
504
505	/*
506	* Copy the source data into the current extent.
507	*/
508	uint32_t const offDst = (uint32_t)(offUnsigned - pExtent->off);
509	uint32_t cbThisWrite = pExtent->cb - offDst;
510	if (cbThisWrite > cbLeftToWrite)
511	cbThisWrite = (uint32_t)cbLeftToWrite;
512	memcpy(&pExtent->abData[offDst], pbSrc, cbThisWrite);
513
514	offUnsigned += cbThisWrite;
515	cbLeftToWrite -= cbThisWrite;
516	if (!cbLeftToWrite)
517	break;
518	pbSrc += cbThisWrite;
519	Assert(offUnsigned == pExtent->off + pExtent->cb);
520
521	/*
522	* Advance to the next extent (emulate the lookup).
523	*/
524	pExtent = RTListGetNext(&pThis->ExtentHead, pExtent, RTVFSMEMEXTENT, Entry);
525	fHit = pExtent && (offUnsigned - pExtent->off < pExtent->cb);
526	}
527
528	/*
529	* Update the state, set return value and return.
530	* Note! There must be no alternative exit path from the loop above.
531	*/
532	pThis->offCurPos = offUnsigned;
533	if ((uint64_t)pThis->Base.ObjInfo.cbObject < offUnsigned)
534	pThis->Base.ObjInfo.cbObject = offUnsigned;
535
536	if (pcbWritten)
537	*pcbWritten = pSgBuf->paSegs[0].cbSeg - cbLeftToWrite;
538	return rc;
539	}
540
541
542	/**
543	* @interface_method_impl{RTVFSIOSTREAMOPS,pfnFlush}
544	*/
545	static DECLCALLBACK(int) rtVfsMemFile_Flush(void *pvThis)
546	{
547	NOREF(pvThis);
548	return VINF_SUCCESS;
549	}
550
551
552	/**
553	* @interface_method_impl{RTVFSIOSTREAMOPS,pfnTell}
554	*/
555	static DECLCALLBACK(int) rtVfsMemFile_Tell(void *pvThis, PRTFOFF poffActual)
556	{
557	PRTVFSMEMFILE pThis = (PRTVFSMEMFILE)pvThis;
558	*poffActual = pThis->offCurPos;
559	return VINF_SUCCESS;
560	}
561
562
563	/**
564	* @interface_method_impl{RTVFSOBJSETOPS,pfnMode}
565	*/
566	static DECLCALLBACK(int) rtVfsMemFile_SetMode(void *pvThis, RTFMODE fMode, RTFMODE fMask)
567	{
568	PRTVFSMEMFILE pThis = (PRTVFSMEMFILE)pvThis;
569	pThis->Base.ObjInfo.Attr.fMode = (pThis->Base.ObjInfo.Attr.fMode & ~fMask) \| fMode;
570	return VINF_SUCCESS;
571	}
572
573
574	/**
575	* @interface_method_impl{RTVFSOBJSETOPS,pfnSetTimes}
576	*/
577	static DECLCALLBACK(int) rtVfsMemFile_SetTimes(void *pvThis, PCRTTIMESPEC pAccessTime, PCRTTIMESPEC pModificationTime,
578	PCRTTIMESPEC pChangeTime, PCRTTIMESPEC pBirthTime)
579	{
580	PRTVFSMEMFILE pThis = (PRTVFSMEMFILE)pvThis;
581
582	if (pAccessTime)
583	pThis->Base.ObjInfo.AccessTime = *pAccessTime;
584	if (pModificationTime)
585	pThis->Base.ObjInfo.ModificationTime = *pModificationTime;
586	if (pChangeTime)
587	pThis->Base.ObjInfo.ChangeTime = *pChangeTime;
588	if (pBirthTime)
589	pThis->Base.ObjInfo.BirthTime = *pBirthTime;
590
591	return VINF_SUCCESS;
592	}
593
594
595	/**
596	* @interface_method_impl{RTVFSOBJSETOPS,pfnSetOwner}
597	*/
598	static DECLCALLBACK(int) rtVfsMemFile_SetOwner(void *pvThis, RTUID uid, RTGID gid)
599	{
600	PRTVFSMEMFILE pThis = (PRTVFSMEMFILE)pvThis;
601
602	if (uid != NIL_RTUID)
603	pThis->Base.ObjInfo.Attr.u.Unix.uid = uid;
604	if (gid != NIL_RTUID)
605	pThis->Base.ObjInfo.Attr.u.Unix.gid = gid;
606
607	return VINF_SUCCESS;
608	}
609
610
611	/**
612	* @interface_method_impl{RTVFSFILEOPS,pfnSeek}
613	*/
614	static DECLCALLBACK(int) rtVfsMemFile_Seek(void *pvThis, RTFOFF offSeek, unsigned uMethod, PRTFOFF poffActual)
615	{
616	PRTVFSMEMFILE pThis = (PRTVFSMEMFILE)pvThis;
617
618	/*
619	* Seek relative to which position.
620	*/
621	uint64_t offWrt;
622	switch (uMethod)
623	{
624	case RTFILE_SEEK_BEGIN:
625	offWrt = 0;
626	break;
627
628	case RTFILE_SEEK_CURRENT:
629	offWrt = pThis->offCurPos;
630	break;
631
632	case RTFILE_SEEK_END:
633	offWrt = pThis->Base.ObjInfo.cbObject;
634	break;
635
636	default:
637	return VERR_INTERNAL_ERROR_5;
638	}
639
640	/*
641	* Calc new position, take care to stay within RTFOFF type bounds.
642	*/
643	uint64_t offNew;
644	if (offSeek == 0)
645	offNew = offWrt;
646	else if (offSeek > 0)
647	{
648	offNew = offWrt + offSeek;
649	if ( offNew < offWrt
650	\|\| offNew > RTFOFF_MAX)
651	offNew = RTFOFF_MAX;
652	}
653	else if ((uint64_t)-offSeek < offWrt)
654	offNew = offWrt + offSeek;
655	else
656	offNew = 0;
657
658	/*
659	* Update the state and set return value.
660	*/
661	if ( pThis->pCurExt
662	&& pThis->pCurExt->off - offNew >= pThis->pCurExt->cb)
663	pThis->pCurExt = NULL;
664	pThis->offCurPos = offNew;
665
666	*poffActual = offNew;
667	return VINF_SUCCESS;
668	}
669
670
671	/**
672	* @interface_method_impl{RTVFSFILEOPS,pfnQuerySize}
673	*/
674	static DECLCALLBACK(int) rtVfsMemFile_QuerySize(void pvThis, uint64_t pcbFile)
675	{
676	PRTVFSMEMFILE pThis = (PRTVFSMEMFILE)pvThis;
677	*pcbFile = pThis->Base.ObjInfo.cbObject;
678	return VINF_SUCCESS;
679	}
680
681
682	/**
683	* @interface_method_impl{RTVFSFILEOPS,pfnSetSize}
684	*/
685	static DECLCALLBACK(int) rtVfsMemFile_SetSize(void *pvThis, uint64_t cbFile, uint32_t fFlags)
686	{
687	NOREF(pvThis); NOREF(cbFile); NOREF(fFlags);
688	AssertMsgFailed(("Lucky you! You get to implement this (or bug bird about it).\n"));
689	return VERR_NOT_IMPLEMENTED;
690	}
691
692
693	/**
694	* @interface_method_impl{RTVFSFILEOPS,pfnQueryMaxSize}
695	*/
696	static DECLCALLBACK(int) rtVfsMemFile_QueryMaxSize(void pvThis, uint64_t pcbMax)
697	{
698	RT_NOREF(pvThis);
699	*pcbMax = ~(size_t)0 >> 1;
700	return VINF_SUCCESS;
701	}
702
703
704	/**
705	* Memory file operations.
706	*/
707	DECL_HIDDEN_CONST(const RTVFSFILEOPS) g_rtVfsMemFileOps =
708	{
709	{ /* Stream */
710	{ /* Obj */
711	RTVFSOBJOPS_VERSION,
712	RTVFSOBJTYPE_FILE,
713	"MemFile",
714	rtVfsMemFile_Close,
715	rtVfsMemFile_QueryInfo,
716	RTVFSOBJOPS_VERSION
717	},
718	RTVFSIOSTREAMOPS_VERSION,
719	RTVFSIOSTREAMOPS_FEAT_NO_SG,
720	rtVfsMemFile_Read,
721	rtVfsMemFile_Write,
722	rtVfsMemFile_Flush,
723	NULL /PollOne/,
724	rtVfsMemFile_Tell,
725	NULL /Skip/,
726	NULL /ZeroFill/,
727	RTVFSIOSTREAMOPS_VERSION,
728	},
729	RTVFSFILEOPS_VERSION,
730	/RTVFSIOFILEOPS_FEAT_NO_AT_OFFSET/ 0,
731	{ /* ObjSet */
732	RTVFSOBJSETOPS_VERSION,
733	RT_UOFFSETOF(RTVFSFILEOPS, ObjSet) - RT_UOFFSETOF(RTVFSFILEOPS, Stream.Obj),
734	rtVfsMemFile_SetMode,
735	rtVfsMemFile_SetTimes,
736	rtVfsMemFile_SetOwner,
737	RTVFSOBJSETOPS_VERSION
738	},
739	rtVfsMemFile_Seek,
740	rtVfsMemFile_QuerySize,
741	rtVfsMemFile_SetSize,
742	rtVfsMemFile_QueryMaxSize,
743	RTVFSFILEOPS_VERSION
744	};
745
746
747	/**
748	* Initialize the RTVFSMEMFILE::Base.ObjInfo specific members.
749	*
750	* @param pObjInfo The object info to init.
751	* @param cbObject The object size set.
752	*/
753	static void rtVfsMemInitObjInfo(PRTFSOBJINFO pObjInfo, uint64_t cbObject)
754	{
755	pObjInfo->cbObject = cbObject;
756	pObjInfo->cbAllocated = cbObject;
757	pObjInfo->Attr.fMode = RTFS_DOS_NT_NORMAL \| RTFS_TYPE_FILE \| RTFS_UNIX_IRWXU;
758	pObjInfo->Attr.enmAdditional = RTFSOBJATTRADD_UNIX;
759	pObjInfo->Attr.u.Unix.uid = NIL_RTUID;
760	pObjInfo->Attr.u.Unix.gid = NIL_RTGID;
761	pObjInfo->Attr.u.Unix.cHardlinks = 1;
762	pObjInfo->Attr.u.Unix.INodeIdDevice = 0;
763	pObjInfo->Attr.u.Unix.INodeId = 0;
764	pObjInfo->Attr.u.Unix.fFlags = 0;
765	pObjInfo->Attr.u.Unix.GenerationId = 0;
766	pObjInfo->Attr.u.Unix.Device = 0;
767	RTTimeNow(&pObjInfo->AccessTime);
768	pObjInfo->ModificationTime = pObjInfo->AccessTime;
769	pObjInfo->ChangeTime = pObjInfo->AccessTime;
770	pObjInfo->BirthTime = pObjInfo->AccessTime;
771	}
772
773
774	/**
775	* Initialize the RTVFSMEMFILE specific members.
776	*
777	* @param pThis The memory file to initialize.
778	* @param cbObject The object size for estimating extent size.
779	* @param fFlags The user specified flags.
780	*/
781	static void rtVfsMemFileInit(PRTVFSMEMFILE pThis, RTFOFF cbObject, uint32_t fFlags)
782	{
783	pThis->offCurPos = 0;
784	pThis->pCurExt = NULL;
785	RTListInit(&pThis->ExtentHead);
786	if (cbObject <= 0)
787	pThis->cbExtent = _4K;
788	else if (cbObject < RTVFSMEM_MAX_EXTENT_SIZE)
789	pThis->cbExtent = fFlags & RTFILE_O_WRITE ? _4K : cbObject;
790	else
791	pThis->cbExtent = RTVFSMEM_MAX_EXTENT_SIZE;
792	}
793
794
795	/**
796	* Rewinds the file to position 0 and clears the WRITE flag if necessary.
797	*
798	* @param pThis The memory file instance.
799	* @param fFlags The user specified flags.
800	*/
801	static void rtVfsMemFileResetAndFixWriteFlag(PRTVFSMEMFILE pThis, uint32_t fFlags)
802	{
803	pThis->pCurExt = RTListGetFirst(&pThis->ExtentHead, RTVFSMEMEXTENT, Entry);
804	pThis->offCurPos = 0;
805
806	if (!(fFlags & RTFILE_O_WRITE))
807	{
808	/** @todo clear RTFILE_O_WRITE from the resulting. */
809	}
810	}
811
812
813	RTDECL(int) RTVfsMemFileCreate(RTVFSIOSTREAM hVfsIos, size_t cbEstimate, PRTVFSFILE phVfsFile)
814	{
815	/*
816	* Create a memory file instance and set the extension size according to the
817	* buffer size. Add the WRITE flag so we can use normal write APIs for
818	* copying the buffer.
819	*/
820	RTVFSFILE hVfsFile;
821	PRTVFSMEMFILE pThis;
822	int rc = RTVfsNewFile(&g_rtVfsMemFileOps, sizeof(*pThis), RTFILE_O_READ \| RTFILE_O_WRITE, NIL_RTVFS, NIL_RTVFSLOCK,
823	&hVfsFile, (void **)&pThis);
824	if (RT_SUCCESS(rc))
825	{
826	rtVfsMemInitObjInfo(&pThis->Base.ObjInfo, 0);
827	rtVfsMemFileInit(pThis, cbEstimate, RTFILE_O_READ \| RTFILE_O_WRITE);
828
829	if (hVfsIos != NIL_RTVFSIOSTREAM)
830	{
831	RTVFSIOSTREAM hVfsIosDst = RTVfsFileToIoStream(hVfsFile);
832	rc = RTVfsUtilPumpIoStreams(hVfsIos, hVfsIosDst, pThis->cbExtent);
833	RTVfsIoStrmRelease(hVfsIosDst);
834	}
835
836	if (RT_SUCCESS(rc))
837	{
838	*phVfsFile = hVfsFile;
839	return VINF_SUCCESS;
840	}
841
842	RTVfsFileRelease(hVfsFile);
843	}
844	return rc;
845	}
846
847
848	RTDECL(int) RTVfsMemIoStrmCreate(RTVFSIOSTREAM hVfsIos, size_t cbEstimate, PRTVFSIOSTREAM phVfsIos)
849	{
850	RTVFSFILE hVfsFile;
851	int rc = RTVfsMemFileCreate(hVfsIos, cbEstimate, &hVfsFile);
852	if (RT_SUCCESS(rc))
853	{
854	*phVfsIos = RTVfsFileToIoStream(hVfsFile);
855	AssertStmt(*phVfsIos != NIL_RTVFSIOSTREAM, rc = VERR_INTERNAL_ERROR_2);
856	RTVfsFileRelease(hVfsFile);
857	}
858	return rc;
859	}
860
861
862	RTDECL(int) RTVfsFileFromBuffer(uint32_t fFlags, void const *pvBuf, size_t cbBuf, PRTVFSFILE phVfsFile)
863	{
864	/*
865	* Create a memory file instance and set the extension size according to the
866	* buffer size. Add the WRITE flag so we can use normal write APIs for
867	* copying the buffer.
868	*/
869	RTVFSFILE hVfsFile;
870	PRTVFSMEMFILE pThis;
871	int rc = RTVfsNewFile(&g_rtVfsMemFileOps, sizeof(*pThis), fFlags \| RTFILE_O_WRITE, NIL_RTVFS, NIL_RTVFSLOCK,
872	&hVfsFile, (void **)&pThis);
873	if (RT_SUCCESS(rc))
874	{
875	rtVfsMemInitObjInfo(&pThis->Base.ObjInfo, cbBuf);
876	rtVfsMemFileInit(pThis, cbBuf, fFlags);
877
878	/*
879	* Copy the buffer and reposition the file pointer to the start.
880	*/
881	rc = RTVfsFileWrite(hVfsFile, pvBuf, cbBuf, NULL);
882	if (RT_SUCCESS(rc))
883	{
884	rtVfsMemFileResetAndFixWriteFlag(pThis, fFlags);
885	*phVfsFile = hVfsFile;
886	return VINF_SUCCESS;
887	}
888	RTVfsFileRelease(hVfsFile);
889	}
890	return rc;
891	}
892
893
894	RTDECL(int) RTVfsIoStrmFromBuffer(uint32_t fFlags, void const *pvBuf, size_t cbBuf, PRTVFSIOSTREAM phVfsIos)
895	{
896	RTVFSFILE hVfsFile;
897	int rc = RTVfsFileFromBuffer(fFlags, pvBuf, cbBuf, &hVfsFile);
898	if (RT_SUCCESS(rc))
899	{
900	*phVfsIos = RTVfsFileToIoStream(hVfsFile);
901	RTVfsFileRelease(hVfsFile);
902	}
903	return rc;
904	}
905
906
907	RTDECL(int) RTVfsMemorizeIoStreamAsFile(RTVFSIOSTREAM hVfsIos, uint32_t fFlags, PRTVFSFILE phVfsFile)
908	{
909	/*
910	* Create a memory file instance and try set the extension size to match
911	* the length of the I/O stream.
912	*/
913	RTFSOBJINFO ObjInfo;
914	int rc = RTVfsIoStrmQueryInfo(hVfsIos, &ObjInfo, RTFSOBJATTRADD_UNIX);
915	if (RT_SUCCESS(rc))
916	{
917	RTVFSFILE hVfsFile;
918	PRTVFSMEMFILE pThis;
919	rc = RTVfsNewFile(&g_rtVfsMemFileOps, sizeof(*pThis), fFlags \| RTFILE_O_WRITE, NIL_RTVFS, NIL_RTVFSLOCK,
920	&hVfsFile, (void **)&pThis);
921	if (RT_SUCCESS(rc))
922	{
923	pThis->Base.ObjInfo = ObjInfo;
924	rtVfsMemFileInit(pThis, ObjInfo.cbObject, fFlags);
925
926	/*
927	* Copy the stream.
928	*/
929	RTVFSIOSTREAM hVfsIosDst = RTVfsFileToIoStream(hVfsFile);
930	rc = RTVfsUtilPumpIoStreams(hVfsIos, hVfsIosDst, pThis->cbExtent);
931	RTVfsIoStrmRelease(hVfsIosDst);
932	if (RT_SUCCESS(rc))
933	{
934	rtVfsMemFileResetAndFixWriteFlag(pThis, fFlags);
935	*phVfsFile = hVfsFile;
936	return VINF_SUCCESS;
937	}
938	RTVfsFileRelease(hVfsFile);
939	}
940	}
941	return rc;
942	}
943

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source: vbox/trunk/src/VBox/Runtime/common/vfs/vfsmemory.cpp@ 74525

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