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[NTFS]
Implement AddRun(). Add support functions and documentation. +ConvertDataRunsToLargeMCB() +ConvertLargeMCBToDataRuns() *SetAttributeDataLength(), *NtfsWriteFile() - Update for AddRun() implementation. Add hack to SetAttributeDataLength() to allow notepad.exe to save files until freeing clusters is implemented. svn path=/branches/GSoC_2016/NTFS/; revision=71942
This commit is contained in:
Trevor Thompson
Thomas Faber
parent
a135ef5864
commit
afe40eb054
4 changed files with 352 additions and 13 deletions
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@ -35,17 +35,309 @@
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/* FUNCTIONS ****************************************************************/
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/**
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* @name AddRun
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* @implemented
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*
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* Adds a run of allocated clusters to a non-resident attribute.
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*
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* @param Vcb
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* Pointer to an NTFS_VCB for the destination volume.
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*
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* @param AttrContext
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* Pointer to an NTFS_ATTR_CONTEXT describing the destination attribute.
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*
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* @param AttrOffset
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* Byte offset of the destination attribute relative to its file record.
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*
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* @param FileRecord
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* Pointer to a complete copy of the file record containing the destination attribute. Must be at least
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* Vcb->NtfsInfo.BytesPerFileRecord bytes long.
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*
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* @param NextAssignedCluster
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* Logical cluster number of the start of the data run being added.
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*
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* @param RunLength
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* How many clusters are in the data run being added. Can't be 0.
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*
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* @return
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* STATUS_SUCCESS on success. STATUS_INVALID_PARAMETER if AttrContext describes a resident attribute.
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* STATUS_INSUFFICIENT_RESOURCES if ConvertDataRunsToLargeMCB() fails.
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* STATUS_BUFFER_TOO_SMALL if ConvertLargeMCBToDataRuns() fails.
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* STATUS_NOT_IMPLEMENTED if we need to migrate the attribute to an attribute list (TODO).
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*
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* @remarks
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* Clusters should have been allocated previously with NtfsAllocateClusters().
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*
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*
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*/
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NTSTATUS
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AddRun(PNTFS_ATTR_CONTEXT AttrContext,
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AddRun(PNTFS_VCB Vcb,
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PNTFS_ATTR_CONTEXT AttrContext,
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ULONG AttrOffset,
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PFILE_RECORD_HEADER FileRecord,
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ULONGLONG NextAssignedCluster,
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ULONG RunLength)
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{
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UNIMPLEMENTED;
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NTSTATUS Status;
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PUCHAR DataRun = (PUCHAR)&AttrContext->Record + AttrContext->Record.NonResident.MappingPairsOffset;
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int DataRunMaxLength;
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PNTFS_ATTR_RECORD DestinationAttribute = (PNTFS_ATTR_RECORD)((ULONG_PTR)FileRecord + AttrOffset);
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LARGE_MCB DataRunsMCB;
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ULONG NextAttributeOffset = AttrOffset + AttrContext->Record.Length;
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ULONGLONG NextVBN = AttrContext->Record.NonResident.LowestVCN;
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// Allocate some memory for the RunBuffer
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PUCHAR RunBuffer = ExAllocatePoolWithTag(NonPagedPool, Vcb->NtfsInfo.BytesPerFileRecord, TAG_NTFS);
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int RunBufferOffset = 0;
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if (!AttrContext->Record.IsNonResident)
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return STATUS_INVALID_PARAMETER;
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return STATUS_NOT_IMPLEMENTED;
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// Convert the data runs to a map control block
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Status = ConvertDataRunsToLargeMCB(DataRun, &DataRunsMCB, &NextVBN);
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if (!NT_SUCCESS(Status))
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{
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DPRINT1("Unable to convert data runs to MCB (probably ran out of memory)!\n");
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return Status;
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}
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// Add newly-assigned clusters to mcb
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FsRtlAddLargeMcbEntry(&DataRunsMCB,
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NextVBN,
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NextAssignedCluster,
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RunLength);
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// Convert the map control block back to encoded data runs
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ConvertLargeMCBToDataRuns(&DataRunsMCB, RunBuffer, Vcb->NtfsInfo.BytesPerCluster, &RunBufferOffset);
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// Get the amount of free space between the start of the of the first data run and the attribute end
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DataRunMaxLength = AttrContext->Record.Length - AttrContext->Record.NonResident.MappingPairsOffset;
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// Do we need to extend the attribute (or convert to attribute list)?
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if (DataRunMaxLength < RunBufferOffset)
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{
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PNTFS_ATTR_RECORD NextAttribute = (PNTFS_ATTR_RECORD)((ULONG_PTR)FileRecord + NextAttributeOffset);
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DataRunMaxLength += Vcb->NtfsInfo.BytesPerFileRecord - NextAttributeOffset - (sizeof(ULONG) * 2);
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// Can we move the end of the attribute?
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if (NextAttribute->Type != AttributeEnd || DataRunMaxLength < RunBufferOffset - 1)
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{
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DPRINT1("FIXME: Need to create attribute list! Max Data Run Length available: %d\n", DataRunMaxLength);
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if (NextAttribute->Type != AttributeEnd)
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DPRINT1("There's another attribute after this one with type %0xlx\n", NextAttribute->Type);
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ExFreePoolWithTag(RunBuffer, TAG_NTFS);
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FsRtlUninitializeLargeMcb(&DataRunsMCB);
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return STATUS_NOT_IMPLEMENTED;
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}
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// calculate position of end markers
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NextAttributeOffset = AttrOffset + AttrContext->Record.NonResident.MappingPairsOffset + RunBufferOffset;
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NextAttributeOffset = ALIGN_UP_BY(NextAttributeOffset, 8);
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// Write the end markers
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NextAttribute = (PNTFS_ATTR_RECORD)((ULONG_PTR)FileRecord + NextAttributeOffset);
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NextAttribute->Type = AttributeEnd;
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NextAttribute->Length = FILE_RECORD_END;
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// Update the length
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DestinationAttribute->Length = NextAttributeOffset - AttrOffset;
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AttrContext->Record.Length = DestinationAttribute->Length;
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// We need to increase the FileRecord size
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FileRecord->BytesInUse = NextAttributeOffset + (sizeof(ULONG) * 2);
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}
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// NOTE: from this point on the original attribute record will contain invalid data in it's runbuffer
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// TODO: Elegant fix? Could we free the old Record and allocate a new one without issue?
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// Update HighestVCN
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DestinationAttribute->NonResident.HighestVCN =
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AttrContext->Record.NonResident.HighestVCN = max(NextVBN - 1 + RunLength,
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AttrContext->Record.NonResident.HighestVCN);
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// Write data runs to destination attribute
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RtlCopyMemory((PVOID)((ULONG_PTR)DestinationAttribute + DestinationAttribute->NonResident.MappingPairsOffset),
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RunBuffer,
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RunBufferOffset);
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// Update the file record
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Status = UpdateFileRecord(Vcb, AttrContext->FileMFTIndex, FileRecord);
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ExFreePoolWithTag(RunBuffer, TAG_NTFS);
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FsRtlUninitializeLargeMcb(&DataRunsMCB);
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NtfsDumpDataRuns((PUCHAR)((ULONG_PTR)DestinationAttribute + DestinationAttribute->NonResident.MappingPairsOffset), 0);
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return Status;
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}
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/**
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* @name ConvertDataRunsToLargeMCB
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* @implemented
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*
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* Converts binary data runs to a map control block.
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*
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* @param DataRun
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* Pointer to the run data
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*
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* @param DataRunsMCB
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* Pointer to an unitialized LARGE_MCB structure.
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*
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* @return
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* STATUS_SUCCESS on success, STATUS_INSUFFICIENT_RESOURCES if we fail to
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* initialize the mcb or add an entry.
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*
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* @remarks
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* Initializes the LARGE_MCB pointed to by DataRunsMCB. If this function succeeds, you
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* need to call FsRtlUninitializeLargeMcb() when you're done with DataRunsMCB. This
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* function will ensure the LargeMCB has been unitialized in case of failure.
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*
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*/
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NTSTATUS
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ConvertDataRunsToLargeMCB(PUCHAR DataRun,
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PLARGE_MCB DataRunsMCB,
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PULONGLONG pNextVBN)
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{
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LONGLONG DataRunOffset;
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ULONGLONG DataRunLength;
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LONGLONG DataRunStartLCN;
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ULONGLONG NextCluster;
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ULONGLONG LastLCN = 0;
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// Initialize the MCB, potentially catch an exception
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_SEH2_TRY{
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FsRtlInitializeLargeMcb(DataRunsMCB, NonPagedPool);
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} _SEH2_EXCEPT(EXCEPTION_EXECUTE_HANDLER) {
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_SEH2_YIELD(return STATUS_INSUFFICIENT_RESOURCES);
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} _SEH2_END;
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while (*DataRun != 0)
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{
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DataRun = DecodeRun(DataRun, &DataRunOffset, &DataRunLength);
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if (DataRunOffset != -1)
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{
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// Normal data run.
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DataRunStartLCN = LastLCN + DataRunOffset;
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LastLCN = DataRunStartLCN;
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NextCluster = LastLCN + DataRunLength;
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_SEH2_TRY{
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if (!FsRtlAddLargeMcbEntry(DataRunsMCB,
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*pNextVBN,
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DataRunStartLCN,
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DataRunLength))
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{
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FsRtlUninitializeLargeMcb(DataRunsMCB);
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return STATUS_INSUFFICIENT_RESOURCES;
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}
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} _SEH2_EXCEPT(EXCEPTION_EXECUTE_HANDLER) {
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FsRtlUninitializeLargeMcb(DataRunsMCB);
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_SEH2_YIELD(return STATUS_INSUFFICIENT_RESOURCES);
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} _SEH2_END;
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}
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*pNextVBN += DataRunLength;
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}
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return STATUS_SUCCESS;
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}
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/**
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* @name ConvertLargeMCBToDataRuns
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* @implemented
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*
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* Converts a map control block to a series of encoded data runs (used by non-resident attributes).
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*
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* @param DataRunsMCB
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* Pointer to a LARGE_MCB structure describing the data runs.
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*
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* @param RunBuffer
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* Pointer to the buffer that will receive the encoded data runs.
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*
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* @param MaxBufferSize
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* Size of RunBuffer, in bytes.
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*
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* @param UsedBufferSize
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* Pointer to a ULONG that will receive the size of the data runs in bytes. Can't be NULL.
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*
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* @return
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* STATUS_SUCCESS on success, STATUS_BUFFER_TOO_SMALL if RunBuffer is too small to contain the
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* complete output.
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*
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*/
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NTSTATUS
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ConvertLargeMCBToDataRuns(PLARGE_MCB DataRunsMCB,
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PUCHAR RunBuffer,
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ULONG MaxBufferSize,
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PULONG UsedBufferSize)
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{
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NTSTATUS Status = STATUS_SUCCESS;
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ULONG RunBufferOffset = 0;
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LONGLONG DataRunOffset;
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ULONGLONG LastLCN = 0;
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LONGLONG Vbn, Lbn, Count;
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DPRINT("\t[Vbn, Lbn, Count]\n");
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// convert each mcb entry to a data run
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for (int i = 0; FsRtlGetNextLargeMcbEntry(DataRunsMCB, i, &Vbn, &Lbn, &Count); i++)
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{
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UCHAR DataRunOffsetSize = 0;
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UCHAR DataRunLengthSize = 0;
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UCHAR ControlByte = 0;
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// [vbn, lbn, count]
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DPRINT("\t[%I64d, %I64d,%I64d]\n", Vbn, Lbn, Count);
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// TODO: check for holes and convert to sparse runs
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DataRunOffset = Lbn - LastLCN;
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LastLCN = Lbn;
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// now we need to determine how to represent DataRunOffset with the minimum number of bytes
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DPRINT("Determining how many bytes needed to represent %I64x\n", DataRunOffset);
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DataRunOffsetSize = GetPackedByteCount(DataRunOffset, TRUE);
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DPRINT("%d bytes needed.\n", DataRunOffsetSize);
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// determine how to represent DataRunLengthSize with the minimum number of bytes
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DPRINT("Determining how many bytes needed to represent %I64x\n", Count);
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DataRunLengthSize = GetPackedByteCount(Count, TRUE);
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DPRINT("%d bytes needed.\n", DataRunLengthSize);
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// ensure the next data run + end marker would be > Max buffer size
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if (RunBufferOffset + 2 + DataRunLengthSize + DataRunOffsetSize > MaxBufferSize)
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{
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Status = STATUS_BUFFER_TOO_SMALL;
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DPRINT1("FIXME: Ran out of room in buffer for data runs!\n");
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break;
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}
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// pack and copy the control byte
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ControlByte = (DataRunOffsetSize << 4) + DataRunLengthSize;
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RunBuffer[RunBufferOffset++] = ControlByte;
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// copy DataRunLength
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RtlCopyMemory(RunBuffer + RunBufferOffset, &Count, DataRunLengthSize);
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RunBufferOffset += DataRunLengthSize;
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// copy DataRunOffset
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RtlCopyMemory(RunBuffer + RunBufferOffset, &DataRunOffset, DataRunOffsetSize);
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RunBufferOffset += DataRunOffsetSize;
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}
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// End of data runs
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RunBuffer[RunBufferOffset++] = 0;
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*UsedBufferSize = RunBufferOffset;
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DPRINT("New Size of DataRuns: %ld\n", *UsedBufferSize);
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return Status;
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}
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PUCHAR
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