VDVfs.cpp@ 96407

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1	/* $Id: VDVfs.cpp 96407 2022-08-22 17:43:14Z vboxsync $ */
2	/** @file
3	* Virtual Disk Container implementation. - VFS glue.
4	*/
5
6	/*
7	* Copyright (C) 2012-2022 Oracle and/or its affiliates.
8	*
9	* This file is part of VirtualBox base platform packages, as
10	* available from https://www.virtualbox.org.
11	*
12	* This program is free software; you can redistribute it and/or
13	* modify it under the terms of the GNU General Public License
14	* as published by the Free Software Foundation, in version 3 of the
15	* License.
16	*
17	* This program is distributed in the hope that it will be useful, but
18	* WITHOUT ANY WARRANTY; without even the implied warranty of
19	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
20	* General Public License for more details.
21	*
22	* You should have received a copy of the GNU General Public License
23	* along with this program; if not, see <https://www.gnu.org/licenses>.
24	*
25	* SPDX-License-Identifier: GPL-3.0-only
26	*/
27
28
29	/*********************************************************************************************************************************
30	* Header Files *
31	*********************************************************************************************************************************/
32	#include <iprt/types.h>
33	#include <iprt/assert.h>
34	#include <iprt/mem.h>
35	#include <iprt/err.h>
36	#include <iprt/asm.h>
37	#include <iprt/string.h>
38	#include <iprt/file.h>
39	#include <iprt/sg.h>
40	#include <iprt/vfslowlevel.h>
41	#include <iprt/poll.h>
42	#include <VBox/vd.h>
43
44	#include "VDInternal.h"
45
46
47	/*********************************************************************************************************************************
48	* Structures and Typedefs *
49	*********************************************************************************************************************************/
50
51	/**
52	* The internal data of a DVM volume I/O stream.
53	*/
54	typedef struct VDVFSFILE
55	{
56	/** The volume the VFS file belongs to. */
57	PVDISK pDisk;
58	/** Current position. */
59	uint64_t offCurPos;
60	/** Flags given during creation. */
61	uint32_t fFlags;
62	} VDVFSFILE;
63	/** Pointer to a the internal data of a DVM volume file. */
64	typedef VDVFSFILE *PVDVFSFILE;
65
66	/**
67	* VD read helper taking care of unaligned accesses.
68	*
69	* @return VBox status code.
70	* @param pDisk VD disk container.
71	* @param off Offset to start reading from.
72	* @param pvBuf Pointer to the buffer to read into.
73	* @param cbRead Amount of bytes to read.
74	*/
75	static int vdReadHelper(PVDISK pDisk, uint64_t off, void *pvBuf, size_t cbRead)
76	{
77	int rc;
78
79	/* Take direct route if the request is sector aligned. */
80	uint64_t const offMisalign = off & 511;
81	size_t const cbMisalign = (off + cbRead) & 511;
82	if ( !offMisalign
83	&& !cbMisalign)
84	rc = VDRead(pDisk, off, pvBuf, cbRead);
85	else
86	{
87	uint8_t pbBuf = (uint8_t )pvBuf;
88	uint8_t abBuf[512];
89
90	/* Unaligned buffered read of head. Aligns the offset. */
91	if (offMisalign)
92	{
93	rc = VDRead(pDisk, off - offMisalign, abBuf, 512);
94	if (RT_SUCCESS(rc))
95	{
96	size_t const cbPart = RT_MIN(512 - offMisalign, cbRead);
97	memcpy(pbBuf, &abBuf[offMisalign], cbPart);
98	pbBuf += cbPart;
99	off += cbPart;
100	cbRead -= cbPart;
101	}
102	}
103	else
104	rc = VINF_SUCCESS;
105
106	/* Aligned direct read. */
107	if ( RT_SUCCESS(rc)
108	&& cbRead >= 512)
109	{
110	Assert(!(off % 512));
111
112	size_t cbPart = cbRead - cbMisalign;
113	Assert(!(cbPart % 512));
114	rc = VDRead(pDisk, off, pbBuf, cbPart);
115	if (RT_SUCCESS(rc))
116	{
117	pbBuf += cbPart;
118	off += cbPart;
119	cbRead -= cbPart;
120	}
121	}
122
123	/* Unaligned buffered read of tail. */
124	if ( RT_SUCCESS(rc)
125	&& cbRead)
126	{
127	Assert(cbRead == cbMisalign);
128	Assert(cbRead < 512);
129	Assert(!(off % 512));
130
131	rc = VDRead(pDisk, off, abBuf, 512);
132	if (RT_SUCCESS(rc))
133	memcpy(pbBuf, abBuf, cbRead);
134	}
135	}
136
137	return rc;
138	}
139
140
141	/**
142	* VD write helper taking care of unaligned accesses.
143	*
144	* @return VBox status code.
145	* @param pDisk VD disk container.
146	* @param off Offset to start writing to.
147	* @param pvSrc Pointer to the buffer to read from.
148	* @param cbWrite Amount of bytes to write.
149	*/
150	static int vdWriteHelper(PVDISK pDisk, uint64_t off, const void *pvSrc, size_t cbWrite)
151	{
152	uint8_t const pbSrc = (uint8_t const )pvSrc;
153	uint8_t abBuf[4096];
154	int rc;
155
156	/*
157	* Take direct route if the request is sector aligned.
158	*/
159	uint64_t const offMisalign = off & 511;
160	size_t const cbMisalign = (off + cbWrite) & 511;
161	if ( !offMisalign
162	&& !cbMisalign)
163	{
164	if (RTListIsEmpty(&pDisk->ListFilterChainWrite))
165	rc = VDWrite(pDisk, off, pbSrc, cbWrite);
166	else
167	{
168	/* Filtered writes must be double buffered as the filter may need to modify the input buffer directly. */
169	do
170	{
171	size_t cbThisWrite = RT_MIN(cbWrite, sizeof(abBuf));
172	rc = VDWrite(pDisk, off, memcpy(abBuf, pbSrc, cbThisWrite), cbThisWrite);
173	if (RT_SUCCESS(rc))
174	{
175	pbSrc += cbThisWrite;
176	off += cbThisWrite;
177	cbWrite -= cbThisWrite;
178	}
179	else
180	break;
181	} while (cbWrite > 0);
182	}
183	}
184	else
185	{
186
187	/*
188	* Unaligned buffered read+write of head. Aligns the offset.
189	*/
190	if (offMisalign)
191	{
192	rc = VDRead(pDisk, off - offMisalign, abBuf, 512);
193	if (RT_SUCCESS(rc))
194	{
195	size_t const cbPart = RT_MIN(512 - offMisalign, cbWrite);
196	memcpy(&abBuf[offMisalign], pbSrc, cbPart);
197	rc = VDWrite(pDisk, off - offMisalign, abBuf, 512);
198	if (RT_SUCCESS(rc))
199	{
200	pbSrc += cbPart;
201	off += cbPart;
202	cbWrite -= cbPart;
203	}
204	}
205	}
206	else
207	rc = VINF_SUCCESS;
208
209	/*
210	* Aligned direct write.
211	*/
212	if ( RT_SUCCESS(rc)
213	&& cbWrite >= 512)
214	{
215	Assert(!(off % 512));
216	size_t cbPart = cbWrite - cbMisalign;
217	Assert(!(cbPart % 512));
218
219	if (RTListIsEmpty(&pDisk->ListFilterChainWrite))
220	{
221	rc = VDWrite(pDisk, off, pbSrc, cbPart);
222	if (RT_SUCCESS(rc))
223	{
224	pbSrc += cbPart;
225	off += cbPart;
226	cbWrite -= cbPart;
227	}
228	}
229	else
230	{
231	/* Filtered writes must be double buffered as the filter may need to modify the input buffer directly. */
232	do
233	{
234	size_t cbThisWrite = RT_MIN(cbPart, sizeof(abBuf));
235	rc = VDWrite(pDisk, off, memcpy(abBuf, pbSrc, cbThisWrite), cbThisWrite);
236	if (RT_SUCCESS(rc))
237	{
238	pbSrc += cbThisWrite;
239	off += cbThisWrite;
240	cbWrite -= cbThisWrite;
241	cbPart -= cbThisWrite;
242	}
243	else
244	break;
245	} while (cbPart > 0);
246	}
247	}
248
249	/*
250	* Unaligned buffered read+write of tail.
251	*/
252	if ( RT_SUCCESS(rc)
253	&& cbWrite > 0)
254	{
255	Assert(cbWrite == cbMisalign);
256	Assert(cbWrite < 512);
257	Assert(!(off % 512));
258
259	rc = VDRead(pDisk, off, abBuf, 512);
260	if (RT_SUCCESS(rc))
261	{
262	memcpy(abBuf, pbSrc, cbWrite);
263	rc = VDWrite(pDisk, off, abBuf, 512);
264	}
265	}
266	}
267
268	return rc;
269	}
270
271
272	/**
273	* @interface_method_impl{RTVFSOBJOPS,pfnClose}
274	*/
275	static DECLCALLBACK(int) vdVfsFile_Close(void *pvThis)
276	{
277	PVDVFSFILE pThis = (PVDVFSFILE)pvThis;
278
279	if (pThis->fFlags & VD_VFSFILE_DESTROY_ON_RELEASE)
280	VDDestroy(pThis->pDisk);
281
282	return VINF_SUCCESS;
283	}
284
285
286	/**
287	* @interface_method_impl{RTVFSOBJOPS,pfnQueryInfo}
288	*/
289	static DECLCALLBACK(int) vdVfsFile_QueryInfo(void *pvThis, PRTFSOBJINFO pObjInfo, RTFSOBJATTRADD enmAddAttr)
290	{
291	PVDVFSFILE pThis = (PVDVFSFILE)pvThis;
292	unsigned const cOpenImages = VDGetCount(pThis->pDisk);
293
294	pObjInfo->cbObject = VDGetSize(pThis->pDisk, cOpenImages - 1);
295	pObjInfo->cbAllocated = 0;
296	for (unsigned iImage = 0; iImage < cOpenImages; iImage++)
297	pObjInfo->cbAllocated += VDGetFileSize(pThis->pDisk, iImage);
298
299	/** @todo enumerate the disk images directly... */
300	RTTimeNow(&pObjInfo->AccessTime);
301	pObjInfo->BirthTime = pObjInfo->AccessTime;
302	pObjInfo->ChangeTime = pObjInfo->AccessTime;
303	pObjInfo->ModificationTime = pObjInfo->AccessTime;
304
305	pObjInfo->Attr.fMode = RTFS_DOS_NT_NORMAL \| RTFS_TYPE_FILE \| 0644;
306	pObjInfo->Attr.enmAdditional = enmAddAttr;
307	switch (enmAddAttr)
308	{
309	case RTFSOBJATTRADD_UNIX:
310	pObjInfo->Attr.u.Unix.uid = NIL_RTUID;
311	pObjInfo->Attr.u.Unix.gid = NIL_RTGID;
312	pObjInfo->Attr.u.Unix.cHardlinks = 1;
313	pObjInfo->Attr.u.Unix.INodeIdDevice = 0;
314	pObjInfo->Attr.u.Unix.INodeId = 0;
315	pObjInfo->Attr.u.Unix.fFlags = 0;
316	pObjInfo->Attr.u.Unix.GenerationId = 0;
317	pObjInfo->Attr.u.Unix.Device = 0;
318	break;
319
320	case RTFSOBJATTRADD_UNIX_OWNER:
321	pObjInfo->Attr.u.UnixOwner.uid = NIL_RTUID;
322	pObjInfo->Attr.u.UnixOwner.szName[0] = '\0';
323	break;
324	case RTFSOBJATTRADD_UNIX_GROUP:
325	pObjInfo->Attr.u.UnixGroup.gid = NIL_RTGID;
326	pObjInfo->Attr.u.UnixGroup.szName[0] = '\0';
327	break;
328	case RTFSOBJATTRADD_EASIZE:
329	pObjInfo->Attr.u.EASize.cb = 0;
330	break;
331
332	default:
333	AssertFailedReturn(VERR_INVALID_PARAMETER);
334	}
335
336	return VINF_SUCCESS;
337	}
338
339
340	/**
341	* @interface_method_impl{RTVFSIOSTREAMOPS,pfnRead}
342	*/
343	static DECLCALLBACK(int) vdVfsFile_Read(void pvThis, RTFOFF off, PCRTSGBUF pSgBuf, bool fBlocking, size_t pcbRead)
344	{
345	PVDVFSFILE pThis = (PVDVFSFILE)pvThis;
346
347	Assert(pSgBuf->cSegs == 1);
348	NOREF(fBlocking);
349
350	/*
351	* Find the current position and check if it's within the volume.
352	*/
353	uint64_t offUnsigned = off < 0 ? pThis->offCurPos : (uint64_t)off;
354	uint64_t const cbImage = VDGetSize(pThis->pDisk, VD_LAST_IMAGE);
355	if (offUnsigned >= cbImage)
356	{
357	if (pcbRead)
358	{
359	*pcbRead = 0;
360	pThis->offCurPos = cbImage;
361	return VINF_EOF;
362	}
363	return VERR_EOF;
364	}
365
366	int rc = VINF_SUCCESS;
367	size_t cbLeftToRead = pSgBuf->paSegs[0].cbSeg;
368	if (offUnsigned + cbLeftToRead <= cbImage)
369	{
370	if (pcbRead)
371	*pcbRead = cbLeftToRead;
372	}
373	else
374	{
375	if (!pcbRead)
376	return VERR_EOF;
377	*pcbRead = cbLeftToRead = (size_t)(cbImage - offUnsigned);
378	rc = VINF_EOF;
379	}
380
381	/*
382	* Ok, we've got a valid stretch within the file. Do the reading.
383	*/
384	if (cbLeftToRead > 0)
385	{
386	int rc2 = vdReadHelper(pThis->pDisk, offUnsigned, pSgBuf->paSegs[0].pvSeg, cbLeftToRead);
387	if (RT_SUCCESS(rc2))
388	offUnsigned += cbLeftToRead;
389	else
390	rc = rc2;
391	}
392
393	pThis->offCurPos = offUnsigned;
394	return rc;
395	}
396
397
398	/**
399	* @interface_method_impl{RTVFSIOSTREAMOPS,pfnWrite}
400	*/
401	static DECLCALLBACK(int) vdVfsFile_Write(void pvThis, RTFOFF off, PCRTSGBUF pSgBuf, bool fBlocking, size_t pcbWritten)
402	{
403	PVDVFSFILE pThis = (PVDVFSFILE)pvThis;
404
405	Assert(pSgBuf->cSegs == 1);
406	NOREF(fBlocking);
407
408	/*
409	* Find the current position and check if it's within the volume.
410	* Writing beyond the end of a volume is not supported.
411	*/
412	uint64_t offUnsigned = off < 0 ? pThis->offCurPos : (uint64_t)off;
413	uint64_t const cbImage = VDGetSize(pThis->pDisk, VD_LAST_IMAGE);
414	if (offUnsigned >= cbImage)
415	{
416	if (pcbWritten)
417	{
418	*pcbWritten = 0;
419	pThis->offCurPos = cbImage;
420	}
421	return VERR_EOF;
422	}
423
424	size_t cbLeftToWrite;
425	if (offUnsigned + pSgBuf->paSegs[0].cbSeg <= cbImage)
426	{
427	cbLeftToWrite = pSgBuf->paSegs[0].cbSeg;
428	if (pcbWritten)
429	*pcbWritten = cbLeftToWrite;
430	}
431	else
432	{
433	if (!pcbWritten)
434	return VERR_EOF;
435	*pcbWritten = cbLeftToWrite = (size_t)(cbImage - offUnsigned);
436	}
437
438	/*
439	* Ok, we've got a valid stretch within the file. Do the reading.
440	*/
441	int rc = VINF_SUCCESS;
442	if (cbLeftToWrite > 0)
443	{
444	rc = vdWriteHelper(pThis->pDisk, offUnsigned, pSgBuf->paSegs[0].pvSeg, cbLeftToWrite);
445	if (RT_SUCCESS(rc))
446	offUnsigned += cbLeftToWrite;
447	}
448
449	pThis->offCurPos = offUnsigned;
450	return rc;
451	}
452
453
454	/**
455	* @interface_method_impl{RTVFSIOSTREAMOPS,pfnFlush}
456	*/
457	static DECLCALLBACK(int) vdVfsFile_Flush(void *pvThis)
458	{
459	PVDVFSFILE pThis = (PVDVFSFILE)pvThis;
460	return VDFlush(pThis->pDisk);
461	}
462
463
464	/**
465	* @interface_method_impl{RTVFSIOSTREAMOPS,pfnTell}
466	*/
467	static DECLCALLBACK(int) vdVfsFile_Tell(void *pvThis, PRTFOFF poffActual)
468	{
469	PVDVFSFILE pThis = (PVDVFSFILE)pvThis;
470	*poffActual = pThis->offCurPos;
471	return VINF_SUCCESS;
472	}
473
474
475	/**
476	* @interface_method_impl{RTVFSOBJSETOPS,pfnSetMode}
477	*/
478	static DECLCALLBACK(int) vdVfsFile_SetMode(void *pvThis, RTFMODE fMode, RTFMODE fMask)
479	{
480	NOREF(pvThis);
481	NOREF(fMode);
482	NOREF(fMask);
483	return VERR_NOT_SUPPORTED;
484	}
485
486
487	/**
488	* @interface_method_impl{RTVFSOBJSETOPS,pfnSetTimes}
489	*/
490	static DECLCALLBACK(int) vdVfsFile_SetTimes(void *pvThis, PCRTTIMESPEC pAccessTime, PCRTTIMESPEC pModificationTime,
491	PCRTTIMESPEC pChangeTime, PCRTTIMESPEC pBirthTime)
492	{
493	NOREF(pvThis);
494	NOREF(pAccessTime);
495	NOREF(pModificationTime);
496	NOREF(pChangeTime);
497	NOREF(pBirthTime);
498	return VERR_NOT_SUPPORTED;
499	}
500
501
502	/**
503	* @interface_method_impl{RTVFSOBJSETOPS,pfnSetOwner}
504	*/
505	static DECLCALLBACK(int) vdVfsFile_SetOwner(void *pvThis, RTUID uid, RTGID gid)
506	{
507	NOREF(pvThis);
508	NOREF(uid);
509	NOREF(gid);
510	return VERR_NOT_SUPPORTED;
511	}
512
513
514	/**
515	* @interface_method_impl{RTVFSFILEOPS,pfnSeek}
516	*/
517	static DECLCALLBACK(int) vdVfsFile_Seek(void *pvThis, RTFOFF offSeek, unsigned uMethod, PRTFOFF poffActual)
518	{
519	PVDVFSFILE pThis = (PVDVFSFILE)pvThis;
520
521	/*
522	* Seek relative to which position.
523	*/
524	uint64_t offWrt;
525	switch (uMethod)
526	{
527	case RTFILE_SEEK_BEGIN:
528	offWrt = 0;
529	break;
530
531	case RTFILE_SEEK_CURRENT:
532	offWrt = pThis->offCurPos;
533	break;
534
535	case RTFILE_SEEK_END:
536	offWrt = VDGetSize(pThis->pDisk, VD_LAST_IMAGE);
537	break;
538
539	default:
540	return VERR_INTERNAL_ERROR_5;
541	}
542
543	/*
544	* Calc new position, take care to stay without bounds.
545	*/
546	uint64_t offNew;
547	if (offSeek == 0)
548	offNew = offWrt;
549	else if (offSeek > 0)
550	{
551	offNew = offWrt + offSeek;
552	if ( offNew < offWrt
553	\|\| offNew > RTFOFF_MAX)
554	offNew = RTFOFF_MAX;
555	}
556	else if ((uint64_t)-offSeek < offWrt)
557	offNew = offWrt + offSeek;
558	else
559	offNew = 0;
560
561	/*
562	* Update the state and set return value.
563	*/
564	pThis->offCurPos = offNew;
565
566	*poffActual = offNew;
567	return VINF_SUCCESS;
568	}
569
570
571	/**
572	* @interface_method_impl{RTVFSFILEOPS,pfnQuerySize}
573	*/
574	static DECLCALLBACK(int) vdVfsFile_QuerySize(void pvThis, uint64_t pcbFile)
575	{
576	PVDVFSFILE pThis = (PVDVFSFILE)pvThis;
577	*pcbFile = VDGetSize(pThis->pDisk, VD_LAST_IMAGE);
578	return VINF_SUCCESS;
579	}
580
581
582	/**
583	* Standard file operations.
584	*/
585	DECL_HIDDEN_CONST(const RTVFSFILEOPS) g_vdVfsStdFileOps =
586	{
587	{ /* Stream */
588	{ /* Obj */
589	RTVFSOBJOPS_VERSION,
590	RTVFSOBJTYPE_FILE,
591	"VDFile",
592	vdVfsFile_Close,
593	vdVfsFile_QueryInfo,
594	NULL,
595	RTVFSOBJOPS_VERSION
596	},
597	RTVFSIOSTREAMOPS_VERSION,
598	RTVFSIOSTREAMOPS_FEAT_NO_SG,
599	vdVfsFile_Read,
600	vdVfsFile_Write,
601	vdVfsFile_Flush,
602	NULL /PollOne/,
603	vdVfsFile_Tell,
604	NULL /Skip/,
605	NULL /ZeroFill/,
606	RTVFSIOSTREAMOPS_VERSION,
607	},
608	RTVFSFILEOPS_VERSION,
609	/RTVFSIOFILEOPS_FEAT_NO_AT_OFFSET/ 0,
610	{ /* ObjSet */
611	RTVFSOBJSETOPS_VERSION,
612	RT_UOFFSETOF(RTVFSFILEOPS, ObjSet) - RT_UOFFSETOF(RTVFSFILEOPS, Stream.Obj),
613	vdVfsFile_SetMode,
614	vdVfsFile_SetTimes,
615	vdVfsFile_SetOwner,
616	RTVFSOBJSETOPS_VERSION
617	},
618	vdVfsFile_Seek,
619	vdVfsFile_QuerySize,
620	NULL /SetSize/,
621	NULL /QueryMaxSize/,
622	RTVFSFILEOPS_VERSION
623	};
624
625
626	VBOXDDU_DECL(int) VDCreateVfsFileFromDisk(PVDISK pDisk, uint32_t fFlags,
627	PRTVFSFILE phVfsFile)
628	{
629	AssertPtrReturn(pDisk, VERR_INVALID_HANDLE);
630	AssertPtrReturn(phVfsFile, VERR_INVALID_POINTER);
631	AssertReturn((fFlags & ~VD_VFSFILE_FLAGS_MASK) == 0, VERR_INVALID_PARAMETER);
632
633	/*
634	* Create the volume file.
635	*/
636	RTVFSFILE hVfsFile;
637	PVDVFSFILE pThis;
638	int rc = RTVfsNewFile(&g_vdVfsStdFileOps, sizeof(*pThis), RTFILE_O_OPEN \| RTFILE_O_READ \| RTFILE_O_WRITE,
639	NIL_RTVFS, NIL_RTVFSLOCK, &hVfsFile, (void **)&pThis);
640	if (RT_SUCCESS(rc))
641	{
642	pThis->offCurPos = 0;
643	pThis->pDisk = pDisk;
644	pThis->fFlags = fFlags;
645
646	*phVfsFile = hVfsFile;
647	return VINF_SUCCESS;
648	}
649
650	return rc;
651	}
652
653
654	/**
655	* @interface_method_impl{RTVFSCHAINELEMENTREG,pfnValidate}
656	*/
657	static DECLCALLBACK(int) vdVfsChain_Validate(PCRTVFSCHAINELEMENTREG pProviderReg, PRTVFSCHAINSPEC pSpec,
658	PRTVFSCHAINELEMSPEC pElement, uint32_t *poffError, PRTERRINFO pErrInfo)
659	{
660	RT_NOREF(pProviderReg, pSpec);
661
662	/*
663	* Basic checks.
664	*/
665	if (pElement->enmTypeIn != RTVFSOBJTYPE_INVALID)
666	return VERR_VFS_CHAIN_MUST_BE_FIRST_ELEMENT;
667	if ( pElement->enmType != RTVFSOBJTYPE_FILE
668	&& pElement->enmType != RTVFSOBJTYPE_IO_STREAM)
669	return VERR_VFS_CHAIN_ONLY_FILE_OR_IOS;
670
671	if (pElement->cArgs < 1)
672	return VERR_VFS_CHAIN_AT_LEAST_ONE_ARG;
673
674	/*
675	* Parse the flag if present, save in pElement->uProvider.
676	*/
677	uint32_t fFlags = (pSpec->fOpenFile & RTFILE_O_ACCESS_MASK) == RTFILE_O_READ
678	? VD_OPEN_FLAGS_READONLY : VD_OPEN_FLAGS_NORMAL;
679	if (pElement->cArgs > 1)
680	{
681	pElement->paArgs[pElement->cArgs - 1].uProvider = true; /* indicates flags */
682	const char *psz = pElement->paArgs[pElement->cArgs - 1].psz;
683	if (*psz)
684	{
685	if ( !strcmp(psz, "ro")
686	\|\| !strcmp(psz, "r"))
687	{
688	fFlags &= ~(VD_OPEN_FLAGS_READONLY \| VD_OPEN_FLAGS_NORMAL);
689	fFlags \|= VD_OPEN_FLAGS_READONLY;
690	}
691	else if (!strcmp(psz, "rw"))
692	{
693	fFlags &= ~(VD_OPEN_FLAGS_READONLY \| VD_OPEN_FLAGS_NORMAL);
694	fFlags \|= VD_OPEN_FLAGS_NORMAL;
695	}
696	else if (strlen(psz) <= 4)
697	{
698	*poffError = pElement->paArgs[pElement->cArgs - 1].offSpec;
699	return RTErrInfoSet(pErrInfo, VERR_VFS_CHAIN_INVALID_ARGUMENT, "Expected 'ro' or 'rw' as argument");
700	}
701	else
702	pElement->paArgs[pElement->cArgs - 1].uProvider = false; /* indicates no flags */
703	}
704	}
705
706	pElement->uProvider = fFlags;
707	if ( pElement->cArgs > 2
708	\|\| (pElement->cArgs == 2 && !pElement->paArgs[pElement->cArgs - 1].uProvider))
709	pElement->uProvider \|= RT_BIT_64(63);
710	return VINF_SUCCESS;
711	}
712
713
714	/**
715	* @interface_method_impl{RTVFSCHAINELEMENTREG,pfnInstantiate}
716	*/
717	static DECLCALLBACK(int) vdVfsChain_Instantiate(PCRTVFSCHAINELEMENTREG pProviderReg, PCRTVFSCHAINSPEC pSpec,
718	PCRTVFSCHAINELEMSPEC pElement, RTVFSOBJ hPrevVfsObj,
719	PRTVFSOBJ phVfsObj, uint32_t *poffError, PRTERRINFO pErrInfo)
720	{
721	RT_NOREF(pProviderReg, pSpec, poffError, pErrInfo);
722	AssertReturn(hPrevVfsObj == NIL_RTVFSOBJ, VERR_VFS_CHAIN_IPE);
723
724	/* Determin the format. */
725	char *pszFormat = NULL;
726	VDTYPE enmType = VDTYPE_INVALID;
727	int rc = VDGetFormat(NULL, NULL, pElement->paArgs[0].psz, VDTYPE_INVALID, &pszFormat, &enmType);
728	if (RT_SUCCESS(rc))
729	{
730	PVDISK pDisk = NULL;
731	rc = VDCreate(NULL, enmType, &pDisk);
732	if (RT_SUCCESS(rc))
733	{
734	if (!(pElement->uProvider & RT_BIT_64(63)))
735	rc = VDOpen(pDisk, pszFormat, pElement->paArgs[0].psz, (uint32_t)pElement->uProvider, NULL);
736	else
737	{
738	uint32_t cChain = pElement->cArgs;
739	if (pElement->cArgs >= 2 && pElement->paArgs[pElement->cArgs - 1].uProvider != 0)
740	cChain--;
741	uint32_t const fFinal = (uint32_t)pElement->uProvider;
742	uint32_t const fReadOnly = (fFinal & ~(VD_OPEN_FLAGS_READONLY \| VD_OPEN_FLAGS_NORMAL)) \| VD_OPEN_FLAGS_READONLY;
743	uint32_t iChain;
744	for (iChain = 0; iChain < cChain && RT_SUCCESS(rc); iChain++)
745	rc = VDOpen(pDisk, pszFormat, pElement->paArgs[iChain].psz, iChain + 1 >= cChain ? fFinal : fReadOnly, NULL);
746	}
747	if (RT_SUCCESS(rc))
748	{
749	RTVFSFILE hVfsFile;
750	rc = VDCreateVfsFileFromDisk(pDisk, VD_VFSFILE_DESTROY_ON_RELEASE, &hVfsFile);
751	if (RT_SUCCESS(rc))
752	{
753	RTStrFree(pszFormat);
754
755	*phVfsObj = RTVfsObjFromFile(hVfsFile);
756	RTVfsFileRelease(hVfsFile);
757
758	if (*phVfsObj != NIL_RTVFSOBJ)
759	return VINF_SUCCESS;
760	return VERR_VFS_CHAIN_CAST_FAILED;
761	}
762	}
763	VDDestroy(pDisk);
764	}
765	RTStrFree(pszFormat);
766	}
767	return rc;
768	}
769
770
771	/**
772	* @interface_method_impl{RTVFSCHAINELEMENTREG,pfnCanReuseElement}
773	*/
774	static DECLCALLBACK(bool) vdVfsChain_CanReuseElement(PCRTVFSCHAINELEMENTREG pProviderReg,
775	PCRTVFSCHAINSPEC pSpec, PCRTVFSCHAINELEMSPEC pElement,
776	PCRTVFSCHAINSPEC pReuseSpec, PCRTVFSCHAINELEMSPEC pReuseElement)
777	{
778	RT_NOREF(pProviderReg, pSpec, pElement, pReuseSpec, pReuseElement);
779	return false;
780	}
781
782
783	/** VFS chain element 'file'. */
784	static RTVFSCHAINELEMENTREG g_rtVfsChainIsoFsVolReg =
785	{
786	/* uVersion = */ RTVFSCHAINELEMENTREG_VERSION,
787	/* fReserved = */ 0,
788	/* pszName = */ "vd",
789	/* ListEntry = */ { NULL, NULL },
790	/* pszHelp = */ "Opens a container image using the VD API.\n"
791	"To open a snapshot chain, start with the root image and end with the more recent diff image.\n"
792	"The final argument can be a flag 'ro' or 'r' for read-only, 'rw' for read-write.",
793	/* pfnValidate = */ vdVfsChain_Validate,
794	/* pfnInstantiate = */ vdVfsChain_Instantiate,
795	/* pfnCanReuseElement = */ vdVfsChain_CanReuseElement,
796	/* uEndMarker = */ RTVFSCHAINELEMENTREG_VERSION
797	};
798
799	RTVFSCHAIN_AUTO_REGISTER_ELEMENT_PROVIDER(&g_rtVfsChainIsoFsVolReg, rtVfsChainIsoFsVolReg);
800

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source: vbox/trunk/src/VBox/Storage/VDVfs.cpp@ 96407

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