VDVfs.cpp@ 55628

Last change on this file since 55628 was 43121, checked in by vboxsync, 12 years ago
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1	/* $Id: VDVfs.cpp 43121 2012-08-30 18:36:48Z vboxsync $ */
2	/** @file
3	* Virtual Disk Container implementation. - VFS glue.
4	*/
5
6	/*
7	* Copyright (C) 2012 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
18
19	/*******************************************************************************
20	* Header Files *
21	*******************************************************************************/
22	#include <iprt/types.h>
23	#include <iprt/assert.h>
24	#include <iprt/mem.h>
25	#include <iprt/err.h>
26	#include <iprt/asm.h>
27	#include <iprt/string.h>
28	#include <iprt/file.h>
29	#include <iprt/sg.h>
30	#include <iprt/vfslowlevel.h>
31	#include <iprt/poll.h>
32	#include <VBox/vd.h>
33
34	/*******************************************************************************
35	* Structures and Typedefs *
36	*******************************************************************************/
37
38	/**
39	* The internal data of a DVM volume I/O stream.
40	*/
41	typedef struct VDVFSFILE
42	{
43	/** The volume the VFS file belongs to. */
44	PVBOXHDD pDisk;
45	/** Current position. */
46	uint64_t offCurPos;
47	/** Flags given during creation. */
48	uint32_t fFlags;
49	} VDVFSFILE;
50	/** Pointer to a the internal data of a DVM volume file. */
51	typedef VDVFSFILE *PVDVFSFILE;
52
53	/**
54	* VD read helper taking care of unaligned accesses.
55	*
56	* @return VBox status code.
57	* @param pDisk VD disk container.
58	* @param off Offset to start reading from.
59	* @param pvBuf Pointer to the buffer to read into.
60	* @param cbRead Amount of bytes to read.
61	*/
62	static int vdReadHelper(PVBOXHDD pDisk, uint64_t off, void *pvBuf, size_t cbRead)
63	{
64	int rc = VINF_SUCCESS;
65
66	/* Take shortcut if possible. */
67	if ( off % 512 == 0
68	&& cbRead % 512 == 0)
69	rc = VDRead(pDisk, off, pvBuf, cbRead);
70	else
71	{
72	uint8_t pbBuf = (uint8_t )pvBuf;
73	uint8_t abBuf[512];
74
75	/* Unaligned access, make it aligned. */
76	if (off % 512 != 0)
77	{
78	uint64_t offAligned = off & ~(uint64_t)(512 - 1);
79	size_t cbToCopy = 512 - (off - offAligned);
80	rc = VDRead(pDisk, offAligned, abBuf, 512);
81	if (RT_SUCCESS(rc))
82	{
83	memcpy(pbBuf, &abBuf[off - offAligned], cbToCopy);
84	pbBuf += cbToCopy;
85	off += cbToCopy;
86	cbRead -= cbToCopy;
87	}
88	}
89
90	if ( RT_SUCCESS(rc)
91	&& (cbRead & ~(uint64_t)(512 - 1)))
92	{
93	size_t cbReadAligned = cbRead & ~(uint64_t)(512 - 1);
94
95	Assert(!(off % 512));
96	rc = VDRead(pDisk, off, pbBuf, cbReadAligned);
97	if (RT_SUCCESS(rc))
98	{
99	pbBuf += cbReadAligned;
100	off += cbReadAligned;
101	cbRead -= cbReadAligned;
102	}
103	}
104
105	if ( RT_SUCCESS(rc)
106	&& cbRead)
107	{
108	Assert(cbRead < 512);
109	Assert(!(off % 512));
110
111	rc = VDRead(pDisk, off, abBuf, 512);
112	if (RT_SUCCESS(rc))
113	memcpy(pbBuf, abBuf, cbRead);
114	}
115	}
116
117	return rc;
118	}
119
120
121	/**
122	* VD write helper taking care of unaligned accesses.
123	*
124	* @return VBox status code.
125	* @param pDisk VD disk container.
126	* @param off Offset to start writing to.
127	* @param pvBuf Pointer to the buffer to read from.
128	* @param cbWrite Amount of bytes to write.
129	*/
130	static int vdWriteHelper(PVBOXHDD pDisk, uint64_t off, const void *pvBuf, size_t cbWrite)
131	{
132	int rc = VINF_SUCCESS;
133
134	/* Take shortcut if possible. */
135	if ( off % 512 == 0
136	&& cbWrite % 512 == 0)
137	rc = VDWrite(pDisk, off, pvBuf, cbWrite);
138	else
139	{
140	uint8_t pbBuf = (uint8_t )pvBuf;
141	uint8_t abBuf[512];
142
143	/* Unaligned access, make it aligned. */
144	if (off % 512 != 0)
145	{
146	uint64_t offAligned = off & ~(uint64_t)(512 - 1);
147	size_t cbToCopy = 512 - (off - offAligned);
148	rc = VDRead(pDisk, offAligned, abBuf, 512);
149	if (RT_SUCCESS(rc))
150	{
151	memcpy(&abBuf[off - offAligned], pbBuf, cbToCopy);
152	rc = VDWrite(pDisk, offAligned, abBuf, 512);
153
154	pbBuf += cbToCopy;
155	off += cbToCopy;
156	cbWrite -= cbToCopy;
157	}
158	}
159
160	if ( RT_SUCCESS(rc)
161	&& (cbWrite & ~(uint64_t)(512 - 1)))
162	{
163	size_t cbWriteAligned = cbWrite & ~(uint64_t)(512 - 1);
164
165	Assert(!(off % 512));
166	rc = VDWrite(pDisk, off, pbBuf, cbWriteAligned);
167	if (RT_SUCCESS(rc))
168	{
169	pbBuf += cbWriteAligned;
170	off += cbWriteAligned;
171	cbWrite -= cbWriteAligned;
172	}
173	}
174
175	if ( RT_SUCCESS(rc)
176	&& cbWrite)
177	{
178	Assert(cbWrite < 512);
179	Assert(!(off % 512));
180
181	rc = VDRead(pDisk, off, abBuf, 512);
182	if (RT_SUCCESS(rc))
183	{
184	memcpy(abBuf, pbBuf, cbWrite);
185	rc = VDWrite(pDisk, off, abBuf, 512);
186	}
187	}
188	}
189
190	return rc;
191	}
192
193
194	/**
195	* @interface_method_impl{RTVFSOBJOPS,pfnClose}
196	*/
197	static DECLCALLBACK(int) vdVfsFile_Close(void *pvThis)
198	{
199	PVDVFSFILE pThis = (PVDVFSFILE)pvThis;
200
201	if (pThis->fFlags & VD_VFSFILE_DESTROY_ON_RELEASE)
202	VDDestroy(pThis->pDisk);
203
204	return VINF_SUCCESS;
205	}
206
207
208	/**
209	* @interface_method_impl{RTVFSOBJOPS,pfnQueryInfo}
210	*/
211	static DECLCALLBACK(int) vdVfsFile_QueryInfo(void *pvThis, PRTFSOBJINFO pObjInfo,
212	RTFSOBJATTRADD enmAddAttr)
213	{
214	NOREF(pvThis);
215	NOREF(pObjInfo);
216	NOREF(enmAddAttr);
217	return VERR_NOT_SUPPORTED;
218	}
219
220
221	/**
222	* @interface_method_impl{RTVFSIOSTREAMOPS,pfnRead}
223	*/
224	static DECLCALLBACK(int) vdVfsFile_Read(void pvThis, RTFOFF off, PCRTSGBUF pSgBuf, bool fBlocking, size_t pcbRead)
225	{
226	PVDVFSFILE pThis = (PVDVFSFILE)pvThis;
227	int rc = VINF_SUCCESS;
228
229	Assert(pSgBuf->cSegs == 1);
230	NOREF(fBlocking);
231
232	/*
233	* Find the current position and check if it's within the volume.
234	*/
235	uint64_t offUnsigned = off < 0 ? pThis->offCurPos : (uint64_t)off;
236	if (offUnsigned >= VDGetSize(pThis->pDisk, VD_LAST_IMAGE))
237	{
238	if (pcbRead)
239	{
240	*pcbRead = 0;
241	pThis->offCurPos = offUnsigned;
242	return VINF_EOF;
243	}
244	return VERR_EOF;
245	}
246
247	size_t cbLeftToRead;
248	if (offUnsigned + pSgBuf->paSegs[0].cbSeg > VDGetSize(pThis->pDisk, VD_LAST_IMAGE))
249	{
250	if (!pcbRead)
251	return VERR_EOF;
252	*pcbRead = cbLeftToRead = (size_t)(VDGetSize(pThis->pDisk, VD_LAST_IMAGE) - offUnsigned);
253	}
254	else
255	{
256	cbLeftToRead = pSgBuf->paSegs[0].cbSeg;
257	if (pcbRead)
258	*pcbRead = cbLeftToRead;
259	}
260
261	/*
262	* Ok, we've got a valid stretch within the file. Do the reading.
263	*/
264	if (cbLeftToRead > 0)
265	{
266	rc = vdReadHelper(pThis->pDisk, (uint64_t)off, pSgBuf->paSegs[0].pvSeg, cbLeftToRead);
267	if (RT_SUCCESS(rc))
268	offUnsigned += cbLeftToRead;
269	}
270
271	pThis->offCurPos = offUnsigned;
272	return rc;
273	}
274
275
276	/**
277	* @interface_method_impl{RTVFSIOSTREAMOPS,pfnWrite}
278	*/
279	static DECLCALLBACK(int) vdVfsFile_Write(void pvThis, RTFOFF off, PCRTSGBUF pSgBuf, bool fBlocking, size_t pcbWritten)
280	{
281	PVDVFSFILE pThis = (PVDVFSFILE)pvThis;
282	int rc = VINF_SUCCESS;
283
284	Assert(pSgBuf->cSegs == 1);
285	NOREF(fBlocking);
286
287	/*
288	* Find the current position and check if it's within the volume.
289	* Writing beyond the end of a volume is not supported.
290	*/
291	uint64_t offUnsigned = off < 0 ? pThis->offCurPos : (uint64_t)off;
292	if (offUnsigned >= VDGetSize(pThis->pDisk, VD_LAST_IMAGE))
293	{
294	if (pcbWritten)
295	{
296	*pcbWritten = 0;
297	pThis->offCurPos = offUnsigned;
298	}
299	return VERR_NOT_SUPPORTED;
300	}
301
302	size_t cbLeftToWrite;
303	if (offUnsigned + pSgBuf->paSegs[0].cbSeg > VDGetSize(pThis->pDisk, VD_LAST_IMAGE))
304	{
305	if (!pcbWritten)
306	return VERR_EOF;
307	*pcbWritten = cbLeftToWrite = (size_t)(VDGetSize(pThis->pDisk, VD_LAST_IMAGE) - offUnsigned);
308	}
309	else
310	{
311	cbLeftToWrite = pSgBuf->paSegs[0].cbSeg;
312	if (pcbWritten)
313	*pcbWritten = cbLeftToWrite;
314	}
315
316	/*
317	* Ok, we've got a valid stretch within the file. Do the reading.
318	*/
319	if (cbLeftToWrite > 0)
320	{
321	rc = vdWriteHelper(pThis->pDisk, (uint64_t)off, pSgBuf->paSegs[0].pvSeg, cbLeftToWrite);
322	if (RT_SUCCESS(rc))
323	offUnsigned += cbLeftToWrite;
324	}
325
326	pThis->offCurPos = offUnsigned;
327	return rc;
328	}
329
330
331	/**
332	* @interface_method_impl{RTVFSIOSTREAMOPS,pfnFlush}
333	*/
334	static DECLCALLBACK(int) vdVfsFile_Flush(void *pvThis)
335	{
336	PVDVFSFILE pThis = (PVDVFSFILE)pvThis;
337	return VDFlush(pThis->pDisk);
338	}
339
340
341	/**
342	* @interface_method_impl{RTVFSIOSTREAMOPS,pfnPollOne}
343	*/
344	static DECLCALLBACK(int) vdVfsFile_PollOne(void *pvThis, uint32_t fEvents, RTMSINTERVAL cMillies, bool fIntr,
345	uint32_t *pfRetEvents)
346	{
347	NOREF(pvThis);
348	int rc;
349	if (fEvents != RTPOLL_EVT_ERROR)
350	{
351	*pfRetEvents = fEvents & ~RTPOLL_EVT_ERROR;
352	rc = VINF_SUCCESS;
353	}
354	else
355	rc = RTVfsUtilDummyPollOne(fEvents, cMillies, fIntr, pfRetEvents);
356	return rc;
357	}
358
359
360	/**
361	* @interface_method_impl{RTVFSIOSTREAMOPS,pfnTell}
362	*/
363	static DECLCALLBACK(int) vdVfsFile_Tell(void *pvThis, PRTFOFF poffActual)
364	{
365	PVDVFSFILE pThis = (PVDVFSFILE)pvThis;
366	*poffActual = pThis->offCurPos;
367	return VINF_SUCCESS;
368	}
369
370
371	/**
372	* @interface_method_impl{RTVFSOBJSETOPS,pfnMode}
373	*/
374	static DECLCALLBACK(int) vdVfsFile_SetMode(void *pvThis, RTFMODE fMode, RTFMODE fMask)
375	{
376	NOREF(pvThis);
377	NOREF(fMode);
378	NOREF(fMask);
379	return VERR_NOT_SUPPORTED;
380	}
381
382
383	/**
384	* @interface_method_impl{RTVFSOBJSETOPS,pfnSetTimes}
385	*/
386	static DECLCALLBACK(int) vdVfsFile_SetTimes(void *pvThis, PCRTTIMESPEC pAccessTime, PCRTTIMESPEC pModificationTime,
387	PCRTTIMESPEC pChangeTime, PCRTTIMESPEC pBirthTime)
388	{
389	NOREF(pvThis);
390	NOREF(pAccessTime);
391	NOREF(pModificationTime);
392	NOREF(pChangeTime);
393	NOREF(pBirthTime);
394	return VERR_NOT_SUPPORTED;
395	}
396
397
398	/**
399	* @interface_method_impl{RTVFSOBJSETOPS,pfnSetOwner}
400	*/
401	static DECLCALLBACK(int) vdVfsFile_SetOwner(void *pvThis, RTUID uid, RTGID gid)
402	{
403	NOREF(pvThis);
404	NOREF(uid);
405	NOREF(gid);
406	return VERR_NOT_SUPPORTED;
407	}
408
409
410	/**
411	* @interface_method_impl{RTVFSFILEOPS,pfnSeek}
412	*/
413	static DECLCALLBACK(int) vdVfsFile_Seek(void *pvThis, RTFOFF offSeek, unsigned uMethod, PRTFOFF poffActual)
414	{
415	PVDVFSFILE pThis = (PVDVFSFILE)pvThis;
416
417	/*
418	* Seek relative to which position.
419	*/
420	uint64_t offWrt;
421	switch (uMethod)
422	{
423	case RTFILE_SEEK_BEGIN:
424	offWrt = 0;
425	break;
426
427	case RTFILE_SEEK_CURRENT:
428	offWrt = pThis->offCurPos;
429	break;
430
431	case RTFILE_SEEK_END:
432	offWrt = VDGetSize(pThis->pDisk, VD_LAST_IMAGE);
433	break;
434
435	default:
436	return VERR_INTERNAL_ERROR_5;
437	}
438
439	/*
440	* Calc new position, take care to stay within bounds.
441	*
442	* @todo: Setting position beyond the end of the disk does not make sense.
443	*/
444	uint64_t offNew;
445	if (offSeek == 0)
446	offNew = offWrt;
447	else if (offSeek > 0)
448	{
449	offNew = offWrt + offSeek;
450	if ( offNew < offWrt
451	\|\| offNew > RTFOFF_MAX)
452	offNew = RTFOFF_MAX;
453	}
454	else if ((uint64_t)-offSeek < offWrt)
455	offNew = offWrt + offSeek;
456	else
457	offNew = 0;
458
459	/*
460	* Update the state and set return value.
461	*/
462	pThis->offCurPos = offNew;
463
464	*poffActual = offNew;
465	return VINF_SUCCESS;
466	}
467
468
469	/**
470	* @interface_method_impl{RTVFSFILEOPS,pfnQuerySize}
471	*/
472	static DECLCALLBACK(int) vdVfsFile_QuerySize(void pvThis, uint64_t pcbFile)
473	{
474	PVDVFSFILE pThis = (PVDVFSFILE)pvThis;
475	*pcbFile = VDGetSize(pThis->pDisk, VD_LAST_IMAGE);
476	return VINF_SUCCESS;
477	}
478
479
480	/**
481	* Standard file operations.
482	*/
483	DECL_HIDDEN_CONST(const RTVFSFILEOPS) g_vdVfsStdFileOps =
484	{
485	{ /* Stream */
486	{ /* Obj */
487	RTVFSOBJOPS_VERSION,
488	RTVFSOBJTYPE_FILE,
489	"VDFile",
490	vdVfsFile_Close,
491	vdVfsFile_QueryInfo,
492	RTVFSOBJOPS_VERSION
493	},
494	RTVFSIOSTREAMOPS_VERSION,
495	RTVFSIOSTREAMOPS_FEAT_NO_SG,
496	vdVfsFile_Read,
497	vdVfsFile_Write,
498	vdVfsFile_Flush,
499	vdVfsFile_PollOne,
500	vdVfsFile_Tell,
501	NULL /Skip/,
502	NULL /ZeroFill/,
503	RTVFSIOSTREAMOPS_VERSION,
504	},
505	RTVFSFILEOPS_VERSION,
506	/RTVFSIOFILEOPS_FEAT_NO_AT_OFFSET/ 0,
507	{ /* ObjSet */
508	RTVFSOBJSETOPS_VERSION,
509	RT_OFFSETOF(RTVFSFILEOPS, Stream.Obj) - RT_OFFSETOF(RTVFSFILEOPS, ObjSet),
510	vdVfsFile_SetMode,
511	vdVfsFile_SetTimes,
512	vdVfsFile_SetOwner,
513	RTVFSOBJSETOPS_VERSION
514	},
515	vdVfsFile_Seek,
516	vdVfsFile_QuerySize,
517	RTVFSFILEOPS_VERSION
518	};
519
520
521	VBOXDDU_DECL(int) VDCreateVfsFileFromDisk(PVBOXHDD pDisk, uint32_t fFlags,
522	PRTVFSFILE phVfsFile)
523	{
524	AssertPtrReturn(pDisk, VERR_INVALID_HANDLE);
525	AssertPtrReturn(phVfsFile, VERR_INVALID_POINTER);
526	AssertReturn((fFlags & ~VD_VFSFILE_FLAGS_MASK) == 0, VERR_INVALID_PARAMETER);
527
528	/*
529	* Create the volume file.
530	*/
531	RTVFSFILE hVfsFile;
532	PVDVFSFILE pThis;
533	int rc = RTVfsNewFile(&g_vdVfsStdFileOps, sizeof(*pThis), RTFILE_O_OPEN \| RTFILE_O_READ \| RTFILE_O_WRITE,
534	NIL_RTVFS, NIL_RTVFSLOCK, &hVfsFile, (void **)&pThis);
535	if (RT_SUCCESS(rc))
536	{
537	pThis->offCurPos = 0;
538	pThis->pDisk = pDisk;
539	pThis->fFlags = fFlags;
540
541	*phVfsFile = hVfsFile;
542	return VINF_SUCCESS;
543	}
544
545	return rc;
546	}
547

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source: vbox/trunk/src/VBox/Storage/VDVfs.cpp@ 55628

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