📄 fcb.c
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/*
* FILE: drivers/fs/vfat/fcb.c
* PURPOSE: Routines to manipulate FCBs.
* COPYRIGHT: See COPYING in the top level directory
* PROJECT: ReactOS kernel
* PROGRAMMER: Jason Filby (jasonfilby@yahoo.com)
* Rex Jolliff (rex@lvcablemodem.com)
* Herve Poussineau (reactos@poussine.freesurf.fr)
*/
/* ------------------------------------------------------- INCLUDES */
#include <wctype.h> /* towlower prototype */
#define NDEBUG
#include "vfat.h"
/* -------------------------------------------------------- DEFINES */
#define TAG_FCB TAG('V', 'F', 'C', 'B')
/* -------------------------------------------------------- PUBLICS */
static ULONG vfatNameHash(ULONG hash, PUNICODE_STRING NameU)
{
PWCHAR last;
PWCHAR curr;
register WCHAR c;
ASSERT(NameU->Buffer[0] != L'.');
curr = NameU->Buffer;
last = NameU->Buffer + NameU->Length / sizeof(WCHAR);
while(curr < last)
{
c = towlower(*curr++);
hash = (hash + (c << 4) + (c >> 4)) * 11;
}
return hash;
}
VOID
vfatSplitPathName(PUNICODE_STRING PathNameU, PUNICODE_STRING DirNameU, PUNICODE_STRING FileNameU)
{
PWCHAR pName;
USHORT Length = 0;
pName = PathNameU->Buffer + PathNameU->Length / sizeof(WCHAR) - 1;
while (*pName != L'\\' && pName >= PathNameU->Buffer)
{
pName--;
Length++;
}
ASSERT(*pName == L'\\' || pName < PathNameU->Buffer);
if (FileNameU)
{
FileNameU->Buffer = pName + 1;
FileNameU->Length = FileNameU->MaximumLength = Length * sizeof(WCHAR);
}
if (DirNameU)
{
DirNameU->Buffer = PathNameU->Buffer;
DirNameU->Length = (pName + 1 - PathNameU->Buffer) * sizeof(WCHAR);
DirNameU->MaximumLength = DirNameU->Length;
}
}
static VOID
vfatInitFcb(PVFATFCB Fcb, PUNICODE_STRING NameU)
{
USHORT PathNameBufferLength;
if (NameU)
PathNameBufferLength = NameU->Length + sizeof(WCHAR);
else
PathNameBufferLength = 0;
Fcb->PathNameBuffer = ExAllocatePool(NonPagedPool, PathNameBufferLength);
if (!Fcb->PathNameBuffer)
{
/* FIXME: what to do if no more memory? */
DPRINT1("Unable to initialize FCB for filename '%wZ'\n", NameU);
KEBUGCHECKEX(0, (ULONG_PTR)Fcb, (ULONG_PTR)NameU, 0, 0);
}
Fcb->PathNameU.Length = 0;
Fcb->PathNameU.Buffer = Fcb->PathNameBuffer;
Fcb->PathNameU.MaximumLength = PathNameBufferLength;
Fcb->ShortNameU.Length = 0;
Fcb->ShortNameU.Buffer = Fcb->ShortNameBuffer;
Fcb->ShortNameU.MaximumLength = sizeof(Fcb->ShortNameBuffer);
Fcb->DirNameU.Buffer = Fcb->PathNameU.Buffer;
if (NameU && NameU->Length)
{
RtlCopyUnicodeString(&Fcb->PathNameU, NameU);
vfatSplitPathName(&Fcb->PathNameU, &Fcb->DirNameU, &Fcb->LongNameU);
}
else
{
Fcb->DirNameU.Buffer = Fcb->LongNameU.Buffer = NULL;
Fcb->DirNameU.MaximumLength = Fcb->DirNameU.Length = 0;
Fcb->LongNameU.MaximumLength = Fcb->LongNameU.Length = 0;
}
RtlZeroMemory(&Fcb->FCBShareAccess, sizeof(SHARE_ACCESS));
Fcb->OpenHandleCount = 0;
}
PVFATFCB
vfatNewFCB(PDEVICE_EXTENSION pVCB, PUNICODE_STRING pFileNameU)
{
PVFATFCB rcFCB;
DPRINT("'%wZ'\n", pFileNameU);
rcFCB = ExAllocateFromNPagedLookasideList(&VfatGlobalData->FcbLookasideList);
if (rcFCB == NULL)
{
return NULL;
}
RtlZeroMemory(rcFCB, sizeof(VFATFCB));
vfatInitFcb(rcFCB, pFileNameU);
if (pVCB->Flags & VCB_IS_FATX)
{
rcFCB->Flags |= FCB_IS_FATX_ENTRY;
rcFCB->Attributes = &rcFCB->entry.FatX.Attrib;
}
else
rcFCB->Attributes = &rcFCB->entry.Fat.Attrib;
rcFCB->Hash.Hash = vfatNameHash(0, &rcFCB->PathNameU);
rcFCB->Hash.self = rcFCB;
rcFCB->ShortHash.self = rcFCB;
ExInitializeResourceLite(&rcFCB->PagingIoResource);
ExInitializeResourceLite(&rcFCB->MainResource);
FsRtlInitializeFileLock(&rcFCB->FileLock, NULL, NULL);
ExInitializeFastMutex(&rcFCB->LastMutex);
rcFCB->RFCB.PagingIoResource = &rcFCB->PagingIoResource;
rcFCB->RFCB.Resource = &rcFCB->MainResource;
rcFCB->RFCB.IsFastIoPossible = FastIoIsNotPossible;
return rcFCB;
}
VOID
vfatDestroyCCB(PVFATCCB pCcb)
{
if (pCcb->SearchPattern.Buffer)
{
ExFreePool(pCcb->SearchPattern.Buffer);
}
ExFreeToNPagedLookasideList(&VfatGlobalData->CcbLookasideList, pCcb);
}
VOID
vfatDestroyFCB(PVFATFCB pFCB)
{
FsRtlUninitializeFileLock(&pFCB->FileLock);
ExFreePool(pFCB->PathNameBuffer);
ExDeleteResourceLite(&pFCB->PagingIoResource);
ExDeleteResourceLite(&pFCB->MainResource);
ExFreeToNPagedLookasideList(&VfatGlobalData->FcbLookasideList, pFCB);
}
BOOLEAN
vfatFCBIsDirectory(PVFATFCB FCB)
{
return *FCB->Attributes & FILE_ATTRIBUTE_DIRECTORY;
}
BOOLEAN
vfatFCBIsRoot(PVFATFCB FCB)
{
return FCB->PathNameU.Length == sizeof(WCHAR) && FCB->PathNameU.Buffer[0] == L'\\' ? TRUE : FALSE;
}
VOID
vfatReleaseFCB(PDEVICE_EXTENSION pVCB, PVFATFCB pFCB)
{
HASHENTRY* entry;
ULONG Index;
ULONG ShortIndex;
PVFATFCB tmpFcb;
DPRINT ("releasing FCB at %x: %wZ, refCount:%d\n",
pFCB,
&pFCB->PathNameU,
pFCB->RefCount);
while (pFCB)
{
Index = pFCB->Hash.Hash % pVCB->HashTableSize;
ShortIndex = pFCB->ShortHash.Hash % pVCB->HashTableSize;
pFCB->RefCount--;
if (pFCB->RefCount == 0)
{
tmpFcb = pFCB->parentFcb;
RemoveEntryList (&pFCB->FcbListEntry);
if (pFCB->Hash.Hash != pFCB->ShortHash.Hash)
{
entry = pVCB->FcbHashTable[ShortIndex];
if (entry->self == pFCB)
{
pVCB->FcbHashTable[ShortIndex] = entry->next;
}
else
{
while (entry->next->self != pFCB)
{
entry = entry->next;
}
entry->next = pFCB->ShortHash.next;
}
}
entry = pVCB->FcbHashTable[Index];
if (entry->self == pFCB)
{
pVCB->FcbHashTable[Index] = entry->next;
}
else
{
while (entry->next->self != pFCB)
{
entry = entry->next;
}
entry->next = pFCB->Hash.next;
}
vfatDestroyFCB (pFCB);
}
else
{
tmpFcb = NULL;
}
pFCB = tmpFcb;
}
}
VOID
vfatAddFCBToTable(PDEVICE_EXTENSION pVCB, PVFATFCB pFCB)
{
ULONG Index;
ULONG ShortIndex;
Index = pFCB->Hash.Hash % pVCB->HashTableSize;
ShortIndex = pFCB->ShortHash.Hash % pVCB->HashTableSize;
InsertTailList (&pVCB->FcbListHead, &pFCB->FcbListEntry);
pFCB->Hash.next = pVCB->FcbHashTable[Index];
pVCB->FcbHashTable[Index] = &pFCB->Hash;
if (pFCB->Hash.Hash != pFCB->ShortHash.Hash)
{
pFCB->ShortHash.next = pVCB->FcbHashTable[ShortIndex];
pVCB->FcbHashTable[ShortIndex] = &pFCB->ShortHash;
}
if (pFCB->parentFcb)
{
pFCB->parentFcb->RefCount++;
}
}
PVFATFCB
vfatGrabFCBFromTable(PDEVICE_EXTENSION pVCB, PUNICODE_STRING PathNameU)
{
PVFATFCB rcFCB;
ULONG Hash;
UNICODE_STRING DirNameU;
UNICODE_STRING FileNameU;
PUNICODE_STRING FcbNameU;
HASHENTRY* entry;
DPRINT("'%wZ'\n", PathNameU);
Hash = vfatNameHash(0, PathNameU);
entry = pVCB->FcbHashTable[Hash % pVCB->HashTableSize];
if (entry)
{
vfatSplitPathName(PathNameU, &DirNameU, &FileNameU);
}
while (entry)
{
if (entry->Hash == Hash)
{
rcFCB = entry->self;
DPRINT("'%wZ' '%wZ'\n", &DirNameU, &rcFCB->DirNameU);
if (RtlEqualUnicodeString(&DirNameU, &rcFCB->DirNameU, TRUE))
{
if (rcFCB->Hash.Hash == Hash)
{
FcbNameU = &rcFCB->LongNameU;
}
else
{
FcbNameU = &rcFCB->ShortNameU;
}
/* compare the file name */
DPRINT("'%wZ' '%wZ'\n", &FileNameU, FcbNameU);
if (RtlEqualUnicodeString(&FileNameU, FcbNameU, TRUE))
{
rcFCB->RefCount++;
CHECKPOINT;
return rcFCB;
}
}
}
entry = entry->next;
}
CHECKPOINT;
return NULL;
}
static NTSTATUS
vfatFCBInitializeCacheFromVolume (PVCB vcb, PVFATFCB fcb)
{
#ifdef USE_ROS_CC_AND_FS
NTSTATUS status;
ULONG fileCacheQuantum;
#endif
PFILE_OBJECT fileObject;
PVFATCCB newCCB;
fileObject = IoCreateStreamFileObject (NULL, vcb->StorageDevice);
newCCB = ExAllocateFromNPagedLookasideList(&VfatGlobalData->CcbLookasideList);
if (newCCB == NULL)
{
return STATUS_INSUFFICIENT_RESOURCES;
}
RtlZeroMemory(newCCB, sizeof (VFATCCB));
fileObject->SectionObjectPointer = &fcb->SectionObjectPointers;
fileObject->FsContext = fcb;
fileObject->FsContext2 = newCCB;
fcb->FileObject = fileObject;
fcb->RefCount++;
#ifdef USE_ROS_CC_AND_FS
fileCacheQuantum = (vcb->FatInfo.BytesPerCluster >= PAGE_SIZE) ?
vcb->FatInfo.BytesPerCluster : PAGE_SIZE;
status = CcRosInitializeFileCache (fileObject,
fileCacheQuantum);
if (!NT_SUCCESS (status))
{
DbgPrint ("CcRosInitializeFileCache failed\n");
KEBUGCHECK (0);
}
#else
/* FIXME: Guard by SEH. */
CcInitializeCacheMap(fileObject,
(PCC_FILE_SIZES)(&fcb->RFCB.AllocationSize),
FALSE,
&VfatGlobalData->CacheMgrCallbacks,
fcb);
#endif
fcb->Flags |= FCB_CACHE_INITIALIZED;
return STATUS_SUCCESS;
}
PVFATFCB
vfatMakeRootFCB(PDEVICE_EXTENSION pVCB)
{
PVFATFCB FCB;
ULONG FirstCluster, CurrentCluster, Size = 0;
NTSTATUS Status = STATUS_SUCCESS;
UNICODE_STRING NameU = RTL_CONSTANT_STRING(L"\\");
FCB = vfatNewFCB(pVCB, &NameU);
if (FCB->Flags & FCB_IS_FATX_ENTRY)
{
memset(FCB->entry.FatX.Filename, ' ', 42);
FCB->entry.FatX.FileSize = pVCB->FatInfo.rootDirectorySectors * pVCB->FatInfo.BytesPerSector;
FCB->entry.FatX.Attrib = FILE_ATTRIBUTE_DIRECTORY;
FCB->entry.FatX.FirstCluster = 1;
Size = pVCB->FatInfo.rootDirectorySectors * pVCB->FatInfo.BytesPerSector;
}
else
{
memset(FCB->entry.Fat.ShortName, ' ', 11);
FCB->entry.Fat.FileSize = pVCB->FatInfo.rootDirectorySectors * pVCB->FatInfo.BytesPerSector;
FCB->entry.Fat.Attrib = FILE_ATTRIBUTE_DIRECTORY;
if (pVCB->FatInfo.FatType == FAT32)
{
CurrentCluster = FirstCluster = pVCB->FatInfo.RootCluster;
FCB->entry.Fat.FirstCluster = (unsigned short)(FirstCluster & 0xffff);
FCB->entry.Fat.FirstClusterHigh = (unsigned short)(FirstCluster >> 16);
while (CurrentCluster != 0xffffffff && NT_SUCCESS(Status))
{
Size += pVCB->FatInfo.BytesPerCluster;
Status = NextCluster (pVCB, FirstCluster, &CurrentCluster, FALSE);
}
}
else
{
FCB->entry.Fat.FirstCluster = 1;
Size = pVCB->FatInfo.rootDirectorySectors * pVCB->FatInfo.BytesPerSector;
}
}
FCB->ShortHash.Hash = FCB->Hash.Hash;
FCB->RefCount = 2;
FCB->dirIndex = 0;
FCB->RFCB.FileSize.QuadPart = Size;
FCB->RFCB.ValidDataLength.QuadPart = Size;
FCB->RFCB.AllocationSize.QuadPart = Size;
FCB->RFCB.IsFastIoPossible = FastIoIsNotPossible;
vfatFCBInitializeCacheFromVolume(pVCB, FCB);
vfatAddFCBToTable(pVCB, FCB);
return(FCB);
}
PVFATFCB
vfatOpenRootFCB(PDEVICE_EXTENSION pVCB)
{
PVFATFCB FCB;
UNICODE_STRING NameU = RTL_CONSTANT_STRING(L"\\");
FCB = vfatGrabFCBFromTable (pVCB, &NameU);
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