fat.c File Reference

#include <freeldr.h>
#include <debug.h>

Include dependency graph for fat.c:

Go to the source code of this file.

Classes
struct	_FAT_VOLUME_INFO
struct	_DIRECTORY_BUFFER

Macros
#define	FAT_IS_END_CLUSTER(clnumber)
#define	TAG_FAT_CHAIN   'CtaT'
#define	TAG_FAT_FILE   'FtaF'
#define	TAG_FAT_VOLUME   'VtaF'
#define	TAG_FAT_BUFFER   'BtaF'
#define	TAG_FAT_CACHE   'HtaF'
#define	FAT_MAX_CACHE_SIZE   (256 * 1024)

Typedefs
typedef struct _FAT_VOLUME_INFO	FAT_VOLUME_INFO
typedef struct _DIRECTORY_BUFFER	DIRECTORY_BUFFER
typedef struct _DIRECTORY_BUFFER *	PDIRECTORY_BUFFER

Functions
	DBG_DEFAULT_CHANNEL (FILESYSTEM)
ULONG	FatDetermineFatType (PFAT_BOOTSECTOR FatBootSector, ULONGLONG PartitionSectorCount)
PVOID	FatBufferDirectory (PFAT_VOLUME_INFO Volume, ULONG DirectoryStartCluster, ULONG *EntryCountPointer, BOOLEAN RootDirectory)
ARC_STATUS	FatLookupFile (PFAT_VOLUME_INFO Volume, PCSTR FileName, PFAT_FILE_INFO FatFileInfoPointer)
void	FatParseShortFileName (PCHAR Buffer, PDIRENTRY DirEntry)
static BOOLEAN	FatGetFatEntry (PFAT_VOLUME_INFO Volume, UINT32 Cluster, PUINT32 ClusterPointer)
static ULONG	FatCountClustersInChain (PFAT_VOLUME_INFO Volume, UINT32 StartCluster)
static BOOLEAN	FatReadClusterChain (PFAT_VOLUME_INFO Volume, UINT32 StartClusterNumber, UINT32 NumberOfClusters, PVOID Buffer, PUINT32 LastClusterNumber)
BOOLEAN	FatReadPartialCluster (PFAT_VOLUME_INFO Volume, ULONG ClusterNumber, ULONG StartingOffset, ULONG Length, PVOID Buffer)
BOOLEAN	FatReadVolumeSectors (PFAT_VOLUME_INFO Volume, ULONG SectorNumber, ULONG SectorCount, PVOID Buffer)
VOID	FatSwapFatBootSector (PFAT_BOOTSECTOR Obj)
VOID	FatSwapFat32BootSector (PFAT32_BOOTSECTOR Obj)
VOID	FatSwapFatXBootSector (PFATX_BOOTSECTOR Obj)
VOID	FatSwapDirEntry (PDIRENTRY Obj)
VOID	FatSwapLFNDirEntry (PLFN_DIRENTRY Obj)
VOID	FatSwapFatXDirEntry (PFATX_DIRENTRY Obj)
FORCEINLINE ULONG	FatNumberOfClusters (_In_ PFAT_VOLUME_INFO Volume)
	Returns the number of clusters of the data area of the FAT volume. This value is computed by taking the total sectors on the disk, subtracting up to the first file area sector, then dividing by the sectors per cluster count.
BOOLEAN	FatOpenVolume (PFAT_VOLUME_INFO Volume, PFAT_BOOTSECTOR BootSector, ULONGLONG PartitionSectorCount)
static BOOLEAN	FatSearchDirectoryBufferForFile (PFAT_VOLUME_INFO Volume, PVOID DirectoryBuffer, ULONG DirectorySize, PCHAR FileName, PFAT_FILE_INFO FatFileInfoPointer)
static BOOLEAN	FatXSearchDirectoryBufferForFile (PFAT_VOLUME_INFO Volume, PVOID DirectoryBuffer, ULONG DirectorySize, PCHAR FileName, PFAT_FILE_INFO FatFileInfoPointer)
static PUCHAR	FatGetFatSector (PFAT_VOLUME_INFO Volume, UINT32 FatSectorNumber)
	Reads 1-4 sectors from FAT using the cache.
static BOOLEAN	FatReadAdjacentClusters (PFAT_VOLUME_INFO Volume, UINT32 StartClusterNumber, UINT32 MaxClusters, PVOID Buffer, PUINT32 ClustersRead, PUINT32 LastClusterNumber)
static BOOLEAN	FatReadFile (PFAT_FILE_INFO FatFileInfo, ULONG BytesToRead, ULONG *BytesRead, PVOID Buffer)
ARC_STATUS	FatClose (ULONG FileId)
ARC_STATUS	FatGetFileInformation (ULONG FileId, FILEINFORMATION *Information)
ARC_STATUS	FatOpen (CHAR *Path, OPENMODE OpenMode, ULONG *FileId)
ARC_STATUS	FatRead (ULONG FileId, VOID *Buffer, ULONG N, ULONG *Count)
ARC_STATUS	FatSeek (ULONG FileId, LARGE_INTEGER *Position, SEEKMODE SeekMode)
ULONGLONG	FatGetVolumeSize (_In_ ULONG DeviceId)
	Returns the size of the FAT volume laid on the storage media device opened via DeviceId.
const DEVVTBL *	FatMount (ULONG DeviceId)

Variables
PFAT_VOLUME_INFO	FatVolumes [MAX_FDS]
LIST_ENTRY	DirectoryBufferListHead = {&DirectoryBufferListHead, &DirectoryBufferListHead}
const DEVVTBL	FatFuncTable
const DEVVTBL	FatXFuncTable

Macro Definition Documentation

FAT_IS_END_CLUSTER

#define FAT_IS_END_CLUSTER

(

clnumber

)

Value:

    (((Volume->FatType == FAT12) && (clnumber >= 0xff8)) || \
    ((Volume->FatType == FAT16 || Volume->FatType == FATX16) && (clnumber >= 0xfff8)) || \
    ((Volume->FatType == FAT32 || Volume->FatType == FATX32) && (clnumber >= 0x0ffffff8)))

Definition at line 25 of file fat.c.

FAT_MAX_CACHE_SIZE

#define FAT_MAX_CACHE_SIZE   (256 * 1024)

Definition at line 36 of file fat.c.

TAG_FAT_BUFFER

#define TAG_FAT_BUFFER   'BtaF'

Definition at line 33 of file fat.c.

TAG_FAT_CACHE

#define TAG_FAT_CACHE   'HtaF'

Definition at line 34 of file fat.c.

TAG_FAT_CHAIN

#define TAG_FAT_CHAIN   'CtaT'

Definition at line 30 of file fat.c.

TAG_FAT_FILE

#define TAG_FAT_FILE   'FtaF'

Definition at line 31 of file fat.c.

TAG_FAT_VOLUME

#define TAG_FAT_VOLUME   'VtaF'

Definition at line 32 of file fat.c.

Typedef Documentation

DIRECTORY_BUFFER

typedef struct _DIRECTORY_BUFFER DIRECTORY_BUFFER

FAT_VOLUME_INFO

typedef struct _FAT_VOLUME_INFO FAT_VOLUME_INFO

PDIRECTORY_BUFFER

typedef struct _DIRECTORY_BUFFER * PDIRECTORY_BUFFER

Function Documentation

DBG_DEFAULT_CHANNEL()

DBG_DEFAULT_CHANNEL

(

FILESYSTEM

)

FatBufferDirectory()

PVOID FatBufferDirectory	(	PFAT_VOLUME_INFO	Volume,
		ULONG	DirectoryStartCluster,
		ULONG *	EntryCountPointer,
		BOOLEAN	RootDirectory
	)

Definition at line 462 of file fat.c.

{
    PDIRECTORY_BUFFER DirectoryBuffer;
    PLIST_ENTRY Entry;
 
    TRACE("FatBufferDirectory() DirectoryStartCluster = %d RootDirectory = %s\n", DirectoryStartCluster, (RootDirectory ? "TRUE" : "FALSE"));
 
    /*
     * For FAT32, the root directory is nothing special. We can treat it the same
     * as a subdirectory.
     */
    if (RootDirectory && Volume->FatType == FAT32)
    {
        DirectoryStartCluster = Volume->RootDirStartCluster;
        RootDirectory = FALSE;
    }
 
    /* Search the list for a match */
    for (Entry = DirectoryBufferListHead.Flink;
         Entry != &DirectoryBufferListHead;
         Entry = Entry->Flink)
    {
        DirectoryBuffer = CONTAINING_RECORD(Entry, DIRECTORY_BUFFER, Link);
 
        /* Check if it matches */
        if ((DirectoryBuffer->Volume == Volume) &&
            (DirectoryBuffer->DirectoryStartCluster == DirectoryStartCluster))
        {
            TRACE("Found cached buffer\n");
            *DirectorySize = DirectoryBuffer->DirectorySize;
            return DirectoryBuffer->Data;
        }
    }
 
    //
    // Calculate the size of the directory
    //
    if (RootDirectory)
    {
        *DirectorySize = Volume->RootDirSectors * Volume->BytesPerSector;
    }
    else
    {
        *DirectorySize = FatCountClustersInChain(Volume, DirectoryStartCluster) * Volume->SectorsPerCluster * Volume->BytesPerSector;
    }
 
    //
    // Attempt to allocate memory for directory buffer
    //
    TRACE("Trying to allocate (DirectorySize) %d bytes.\n", *DirectorySize);
    DirectoryBuffer = FrLdrTempAlloc(*DirectorySize + sizeof(DIRECTORY_BUFFER),
                                     TAG_FAT_BUFFER);
 
    if (DirectoryBuffer == NULL)
    {
        return NULL;
    }
 
    //
    // Now read directory contents into DirectoryBuffer
    //
    if (RootDirectory)
    {
        if (!FatReadVolumeSectors(Volume, Volume->RootDirSectorStart, Volume->RootDirSectors, DirectoryBuffer->Data))
        {
            FrLdrTempFree(DirectoryBuffer, TAG_FAT_BUFFER);
            return NULL;
        }
    }
    else
    {
        if (!FatReadClusterChain(Volume, DirectoryStartCluster, 0xFFFFFFFF, DirectoryBuffer->Data, NULL))
        {
            FrLdrTempFree(DirectoryBuffer, TAG_FAT_BUFFER);
            return NULL;
        }
    }
 
    /* Enqueue it in the list */
    DirectoryBuffer->Volume = Volume;
    DirectoryBuffer->DirectoryStartCluster = DirectoryStartCluster;
    DirectoryBuffer->DirectorySize = *DirectorySize;
    InsertTailList(&DirectoryBufferListHead, &DirectoryBuffer->Link);
 
    return DirectoryBuffer->Data;
}

Referenced by FatLookupFile().

FatClose()

ARC_STATUS FatClose

(

ULONG

FileId

)

Definition at line 1461 of file fat.c.

{
    PFAT_FILE_INFO FileHandle = FsGetDeviceSpecific(FileId);
 
    FrLdrTempFree(FileHandle, TAG_FAT_FILE);
 
    return ESUCCESS;
}

FatCountClustersInChain()

static ULONG FatCountClustersInChain ( PFAT_VOLUME_INFO  Volume, UINT32  StartCluster  )

static

Definition at line 1108 of file fat.c.

{
    ULONG    ClusterCount = 0;
 
    TRACE("FatCountClustersInChain() StartCluster = %d\n", StartCluster);
 
    while (1)
    {
        //
        // If end of chain then break out of our cluster counting loop
        //
        if (FAT_IS_END_CLUSTER(StartCluster))
        {
            break;
        }
 
        //
        // Increment count
        //
        ClusterCount++;
 
        //
        // Get next cluster
        //
        if (!FatGetFatEntry(Volume, StartCluster, &StartCluster))
        {
            return 0;
        }
    }
 
    TRACE("FatCountClustersInChain() ClusterCount = %d\n", ClusterCount);
 
    return ClusterCount;
}

Referenced by FatBufferDirectory().

FatDetermineFatType()

ULONG FatDetermineFatType	(	PFAT_BOOTSECTOR	FatBootSector,
		ULONGLONG	PartitionSectorCount
	)

Definition at line 396 of file fat.c.

{
    ULONG            RootDirSectors;
    ULONG            DataSectorCount;
    ULONG            SectorsPerFat;
    ULONG            TotalSectors;
    ULONG            CountOfClusters;
    PFAT32_BOOTSECTOR    Fat32BootSector = (PFAT32_BOOTSECTOR)FatBootSector;
    PFATX_BOOTSECTOR    FatXBootSector = (PFATX_BOOTSECTOR)FatBootSector;
 
    if (0 == strncmp(FatXBootSector->FileSystemType, "FATX", 4))
    {
        CountOfClusters = (ULONG)(PartitionSectorCount / FatXBootSector->SectorsPerCluster);
        if (CountOfClusters < 65525)
        {
            /* Volume is FATX16 */
            return FATX16;
        }
        else
        {
            /* Volume is FAT32 */
            return FATX32;
        }
    }
    else
    {
        RootDirSectors = ((SWAPW(FatBootSector->RootDirEntries) * 32) + (SWAPW(FatBootSector->BytesPerSector) - 1)) / SWAPW(FatBootSector->BytesPerSector);
        SectorsPerFat = SWAPW(FatBootSector->SectorsPerFat) ? SWAPW(FatBootSector->SectorsPerFat) : SWAPD(Fat32BootSector->SectorsPerFatBig);
        TotalSectors = SWAPW(FatBootSector->TotalSectors) ? SWAPW(FatBootSector->TotalSectors) : SWAPD(FatBootSector->TotalSectorsBig);
        DataSectorCount = TotalSectors - (SWAPW(FatBootSector->ReservedSectors) + (FatBootSector->NumberOfFats * SectorsPerFat) + RootDirSectors);
 
//mjl
        if (FatBootSector->SectorsPerCluster == 0)
            CountOfClusters = 0;
        else
            CountOfClusters = DataSectorCount / FatBootSector->SectorsPerCluster;
 
        if (CountOfClusters < 4085)
        {
            /* Volume is FAT12 */
            return FAT12;
        }
        else if (CountOfClusters < 65525)
        {
            /* Volume is FAT16 */
            return FAT16;
        }
        else
        {
            /* Volume is FAT32 */
            return FAT32;
        }
    }
}

Referenced by FatOpenVolume().

FatGetFatEntry()

static BOOLEAN FatGetFatEntry ( PFAT_VOLUME_INFO  Volume, UINT32  Cluster, PUINT32  ClusterPointer  )

static

Definition at line 1018 of file fat.c.

{
    UINT32 FatOffset, ThisFatSecNum, ThisFatEntOffset, fat;
    PUCHAR ReadBuffer;
 
    TRACE("FatGetFatEntry() Retrieving FAT entry for cluster %d.\n", Cluster);
 
    switch(Volume->FatType)
    {
    case FAT12:
 
        FatOffset = Cluster + (Cluster / 2);
        ThisFatSecNum = FatOffset / Volume->BytesPerSector;
        ThisFatEntOffset = (FatOffset % Volume->BytesPerSector);
 
        TRACE("FatOffset: %d\n", FatOffset);
        TRACE("ThisFatSecNum: %d\n", ThisFatSecNum);
        TRACE("ThisFatEntOffset: %d\n", ThisFatEntOffset);
 
        // The cluster pointer can span within two sectors, but the FatGetFatSector function
        // reads 4 sectors most times, except when we are at the edge of FAT cache
        // and/or FAT region on the disk. For FAT12 the whole FAT would be cached so
        // there will be no situation when the first sector is at the end of the cache
        // and the next one is in the beginning
 
        ReadBuffer = FatGetFatSector(Volume, ThisFatSecNum);
        if (!ReadBuffer)
        {
            return FALSE;
        }
 
        fat = *((USHORT *) (ReadBuffer + ThisFatEntOffset));
        fat = SWAPW(fat);
        if (Cluster & 0x0001)
            fat = fat >> 4;    /* Cluster number is ODD */
        else
            fat = fat & 0x0FFF;    /* Cluster number is EVEN */
 
        break;
 
    case FAT16:
    case FATX16:
 
        FatOffset = (Cluster * 2);
        ThisFatSecNum = FatOffset / Volume->BytesPerSector;
        ThisFatEntOffset = (FatOffset % Volume->BytesPerSector);
 
        ReadBuffer = FatGetFatSector(Volume, ThisFatSecNum);
        if (!ReadBuffer)
        {
            return FALSE;
        }
 
        fat = *((USHORT *) (ReadBuffer + ThisFatEntOffset));
        fat = SWAPW(fat);
 
        break;
 
    case FAT32:
    case FATX32:
 
        FatOffset = (Cluster * 4);
        ThisFatSecNum = FatOffset / Volume->BytesPerSector;
        ThisFatEntOffset = (FatOffset % Volume->BytesPerSector);
 
        ReadBuffer = FatGetFatSector(Volume, ThisFatSecNum);
        if (!ReadBuffer)
        {
            return FALSE;
        }
 
        // Get the fat entry
        fat = (*((ULONG *) (ReadBuffer + ThisFatEntOffset))) & 0x0FFFFFFF;
        fat = SWAPD(fat);
 
        break;
 
    default:
        ERR("Unknown FAT type %d\n", Volume->FatType);
        return FALSE;
    }
 
    TRACE("FAT entry is 0x%x.\n", fat);
 
    *ClusterPointer = fat;
 
    return TRUE;
}

Referenced by FatCountClustersInChain(), FatReadAdjacentClusters(), FatReadFile(), and FatSeek().

FatGetFatSector()

static PUCHAR FatGetFatSector ( PFAT_VOLUME_INFO  Volume, UINT32  FatSectorNumber  )

static

Reads 1-4 sectors from FAT using the cache.

Definition at line 980 of file fat.c.

{
    UINT32 SectorNumAbsolute = Volume->ActiveFatSectorStart + FatSectorNumber;
    UINT32 CacheIndex = FatSectorNumber % Volume->FatCacheSize;
 
    ASSERT(FatSectorNumber < Volume->SectorsPerFat);
 
    // cache miss
    if (Volume->FatCacheIndex[CacheIndex] != SectorNumAbsolute)
    {
        UINT32 SectorsToRead = min(Volume->FatCacheSize - CacheIndex, min(Volume->SectorsPerFat - SectorNumAbsolute, 4));
        UINT8 i;
 
        if (!FatReadVolumeSectors(Volume, SectorNumAbsolute, SectorsToRead, &Volume->FatCache[CacheIndex * Volume->BytesPerSector]))
        {
            return NULL;
        }
 
        for (i = 0; i < SectorsToRead; i++)
        {
            Volume->FatCacheIndex[CacheIndex + i] = SectorNumAbsolute + i;
        }
 
        TRACE("FAT cache miss: read sector 0x%x from disk\n", SectorNumAbsolute);
    }
    else
    {
        TRACE("FAT cache hit: sector 0x%x present\n", SectorNumAbsolute);
    }
 
    return &Volume->FatCache[CacheIndex * Volume->BytesPerSector];
}

Referenced by FatGetFatEntry().

FatGetFileInformation()

ARC_STATUS FatGetFileInformation	(	ULONG	FileId,
		FILEINFORMATION *	Information
	)

Definition at line 1470 of file fat.c.

{
    PFAT_FILE_INFO FileHandle = FsGetDeviceSpecific(FileId);
 
    RtlZeroMemory(Information, sizeof(*Information));
    Information->EndingAddress.LowPart = FileHandle->FileSize;
    Information->CurrentAddress.LowPart = FileHandle->FilePointer;
 
    /* Set the ARC file attributes */
    Information->Attributes = FileHandle->Attributes;
 
    /* Copy the file name, perhaps truncated, and NUL-terminated */
    Information->FileNameLength = min(FileHandle->FileNameLength, sizeof(Information->FileName) - 1);
    RtlCopyMemory(Information->FileName, FileHandle->FileName, Information->FileNameLength);
    Information->FileName[Information->FileNameLength] = ANSI_NULL;
 
    TRACE("FatGetFileInformation(%lu) -> FileSize = %lu, FilePointer = 0x%lx\n",
          FileId, Information->EndingAddress.LowPart, Information->CurrentAddress.LowPart);
 
    return ESUCCESS;
}

FatGetVolumeSize()

ULONGLONG FatGetVolumeSize

(

_In_ ULONG

DeviceId

)

Returns the size of the FAT volume laid on the storage media device opened via DeviceId.

Definition at line 1616 of file fat.c.

{
    PFAT_VOLUME_INFO Volume = FatVolumes[DeviceId];
    ASSERT(Volume);
    return (ULONGLONG)Volume->TotalSectors * Volume->BytesPerSector;
}

Referenced by FsGetVolumeSize().

FatLookupFile()

ARC_STATUS FatLookupFile	(	PFAT_VOLUME_INFO	Volume,
		PCSTR	FileName,
		PFAT_FILE_INFO	FatFileInfoPointer
	)

Definition at line 818 of file fat.c.

{
    ULONG        NumberOfPathParts;
    ULONG        i;
    CHAR        PathPart[261];
    PVOID        DirectoryBuffer;
    ULONG        DirectoryStartCluster = 0;
    ULONG        DirectorySize;
    FAT_FILE_INFO    FatFileInfo;
 
    TRACE("FatLookupFile() FileName = %s\n", FileName);
 
    RtlZeroMemory(FatFileInfoPointer, sizeof(FAT_FILE_INFO));
 
    /* Skip leading path separator, if any */
    if (*FileName == '\\' || *FileName == '/')
        ++FileName;
    PathPart[0] = ANSI_NULL;
 
    //
    // Figure out how many sub-directories we are nested in
    //
    NumberOfPathParts = FsGetNumPathParts(FileName);
 
    //
    // Loop once for each part
    //
    for (i=0; i<NumberOfPathParts; i++)
    {
        //
        // Get first path part
        //
        FsGetFirstNameFromPath(PathPart, FileName);
 
        //
        // Advance to the next part of the path
        //
        for (; (*FileName != '\\') && (*FileName != '/') && (*FileName != '\0'); FileName++)
        {
        }
        FileName++;
 
        //
        // Buffer the directory contents
        //
        DirectoryBuffer = FatBufferDirectory(Volume, DirectoryStartCluster, &DirectorySize, (i == 0) );
        if (DirectoryBuffer == NULL)
        {
            return ENOMEM;
        }
 
        //
        // Search for file name in directory
        //
        if (ISFATX(Volume->FatType))
        {
            if (!FatXSearchDirectoryBufferForFile(Volume, DirectoryBuffer, DirectorySize, PathPart, &FatFileInfo))
            {
                return ENOENT;
            }
        }
        else
        {
            if (!FatSearchDirectoryBufferForFile(Volume, DirectoryBuffer, DirectorySize, PathPart, &FatFileInfo))
            {
                return ENOENT;
            }
        }
 
        //
        // If we have another sub-directory to go then
        // grab the start cluster and free the fat chain array
        //
        if ((i+1) < NumberOfPathParts)
        {
            //
            // Check if current entry is a directory
            //
            if (!(FatFileInfo.Attributes & FAT_ATTR_DIRECTORY))
            {
                return ENOTDIR;
            }
            DirectoryStartCluster = FatFileInfo.StartCluster;
        }
    }
 
    RtlCopyMemory(FatFileInfoPointer, &FatFileInfo, sizeof(FatFileInfo));
 
    /* Re-map the attributes to ARC file attributes */
    FatFileInfoPointer->Attributes = 0;
    if (FatFileInfo.Attributes & FAT_ATTR_READONLY)
        FatFileInfoPointer->Attributes |= ReadOnlyFile;
    if (FatFileInfo.Attributes & FAT_ATTR_HIDDEN)
        FatFileInfoPointer->Attributes |= HiddenFile;
    if (FatFileInfo.Attributes & FAT_ATTR_SYSTEM)
        FatFileInfoPointer->Attributes |= SystemFile;
    if (FatFileInfo.Attributes & FAT_ATTR_ARCHIVE)
        FatFileInfoPointer->Attributes |= ArchiveFile;
    if (FatFileInfo.Attributes & FAT_ATTR_DIRECTORY)
        FatFileInfoPointer->Attributes |= DirectoryFile;
 
    /* Copy the file name, perhaps truncated */
    FatFileInfoPointer->FileNameLength = (ULONG)strlen(PathPart);
    FatFileInfoPointer->FileNameLength = min(FatFileInfoPointer->FileNameLength, sizeof(FatFileInfoPointer->FileName) - 1);
    RtlCopyMemory(FatFileInfoPointer->FileName, PathPart, FatFileInfoPointer->FileNameLength);
 
    return ESUCCESS;
}

Referenced by FatOpen().

FatMount()

const DEVVTBL * FatMount

(

ULONG

DeviceId

)

Definition at line 1645 of file fat.c.

{
    PFAT_VOLUME_INFO Volume;
    UCHAR Buffer[SECTOR_SIZE];
    PFAT_BOOTSECTOR BootSector = (PFAT_BOOTSECTOR)Buffer;
    PFAT32_BOOTSECTOR BootSector32 = (PFAT32_BOOTSECTOR)Buffer;
    PFATX_BOOTSECTOR BootSectorX = (PFATX_BOOTSECTOR)Buffer;
    FILEINFORMATION FileInformation;
    LARGE_INTEGER Position;
    ULONG Count;
    ULARGE_INTEGER SectorCount;
    ARC_STATUS Status;
 
    TRACE("Enter FatMount(%lu)\n", DeviceId);
 
    //
    // Allocate data for volume information
    //
    Volume = FrLdrTempAlloc(sizeof(FAT_VOLUME_INFO), TAG_FAT_VOLUME);
    if (!Volume)
        return NULL;
    RtlZeroMemory(Volume, sizeof(FAT_VOLUME_INFO));
 
    //
    // Read the BootSector
    //
    Position.QuadPart = 0;
    Status = ArcSeek(DeviceId, &Position, SeekAbsolute);
    if (Status != ESUCCESS)
    {
        FrLdrTempFree(Volume, TAG_FAT_VOLUME);
        return NULL;
    }
    Status = ArcRead(DeviceId, Buffer, sizeof(Buffer), &Count);
    if (Status != ESUCCESS || Count != sizeof(Buffer))
    {
        FrLdrTempFree(Volume, TAG_FAT_VOLUME);
        return NULL;
    }
 
    //
    // Check if BootSector is valid. If no, return early
    //
    if (!RtlEqualMemory(BootSector->FileSystemType, "FAT12   ", 8) &&
        !RtlEqualMemory(BootSector->FileSystemType, "FAT16   ", 8) &&
        !RtlEqualMemory(BootSector32->FileSystemType, "FAT32   ", 8) &&
        !RtlEqualMemory(BootSectorX->FileSystemType, "FATX", 4))
    {
        FrLdrTempFree(Volume, TAG_FAT_VOLUME);
        return NULL;
    }
 
    //
    // Determine sector count
    //
    Status = ArcGetFileInformation(DeviceId, &FileInformation);
    if (Status != ESUCCESS)
    {
        FrLdrTempFree(Volume, TAG_FAT_VOLUME);
        return NULL;
    }
    SectorCount.QuadPart = (FileInformation.EndingAddress.QuadPart - FileInformation.StartingAddress.QuadPart);
    SectorCount.QuadPart /= SECTOR_SIZE;
 
    //
    // Keep device id
    //
    Volume->DeviceId = DeviceId;
 
    //
    // Really open the volume
    //
    if (!FatOpenVolume(Volume, BootSector, SectorCount.QuadPart))
    {
        FrLdrTempFree(Volume, TAG_FAT_VOLUME);
        return NULL;
    }
 
    //
    // Remember FAT volume information
    //
    FatVolumes[DeviceId] = Volume;
 
    //
    // Return success
    //
    TRACE("FatMount(%lu) success\n", DeviceId);
    return (ISFATX(Volume->FatType) ? &FatXFuncTable : &FatFuncTable);
}

FatNumberOfClusters()

FORCEINLINE ULONG FatNumberOfClusters

(

_In_ PFAT_VOLUME_INFO

Volume

)

Returns the number of clusters of the data area of the FAT volume. This value is computed by taking the total sectors on the disk, subtracting up to the first file area sector, then dividing by the sectors per cluster count.

Note

Relies on the FAT_VOLUME_INFO fields already computed by FatOpenVolume().

See also

https://github.com/reactos/reactos/blob/435482912c6dc0aaa4371e37b7336b2b1291e65f/drivers/filesystems/fastfat/fat.h#L460 https://github.com/reactos/reactos/blob/435482912c6dc0aaa4371e37b7336b2b1291e65f/drivers/filesystems/vfatfs/fsctl.c#L24

Definition at line 154 of file fat.c.

{
    return ((Volume->TotalSectors - Volume->DataSectorStart) / Volume->SectorsPerCluster);
}

FatOpen()

ARC_STATUS FatOpen	(	CHAR *	Path,
		OPENMODE	OpenMode,
		ULONG *	FileId
	)

Definition at line 1492 of file fat.c.

{
    PFAT_VOLUME_INFO FatVolume;
    FAT_FILE_INFO TempFileInfo;
    PFAT_FILE_INFO FileHandle;
    ULONG DeviceId;
    BOOLEAN IsDirectory;
    ARC_STATUS Status;
 
    if (OpenMode != OpenReadOnly && OpenMode != OpenDirectory)
        return EACCES;
 
    DeviceId = FsGetDeviceId(*FileId);
    FatVolume = FatVolumes[DeviceId];
 
    TRACE("FatOpen() FileName = %s\n", Path);
 
    RtlZeroMemory(&TempFileInfo, sizeof(TempFileInfo));
    Status = FatLookupFile(FatVolume, Path, &TempFileInfo);
    if (Status != ESUCCESS)
        return ENOENT;
 
    //
    // Check if caller opened what he expected (dir vs file)
    //
    IsDirectory = !!(TempFileInfo.Attributes & DirectoryFile);
    if (IsDirectory && OpenMode != OpenDirectory)
        return EISDIR;
    else if (!IsDirectory && OpenMode != OpenReadOnly)
        return ENOTDIR;
 
    FileHandle = FrLdrTempAlloc(sizeof(FAT_FILE_INFO), TAG_FAT_FILE);
    if (!FileHandle)
        return ENOMEM;
 
    RtlCopyMemory(FileHandle, &TempFileInfo, sizeof(FAT_FILE_INFO));
    FileHandle->Volume = FatVolume;
 
    FsSetDeviceSpecific(*FileId, FileHandle);
    return ESUCCESS;
}

FatOpenVolume()

BOOLEAN FatOpenVolume	(	PFAT_VOLUME_INFO	Volume,
		PFAT_BOOTSECTOR	BootSector,
		ULONGLONG	PartitionSectorCount
	)

Definition at line 160 of file fat.c.

{
    char ErrMsg[80];
    ULONG FatSize, i;
    PFAT_BOOTSECTOR    FatVolumeBootSector;
    PFAT32_BOOTSECTOR Fat32VolumeBootSector;
    PFATX_BOOTSECTOR FatXVolumeBootSector;
 
    TRACE("FatOpenVolume() DeviceId = %d\n", Volume->DeviceId);
 
    //
    // Allocate the memory to hold the boot sector
    //
    FatVolumeBootSector = (PFAT_BOOTSECTOR)BootSector;
    Fat32VolumeBootSector = (PFAT32_BOOTSECTOR)BootSector;
    FatXVolumeBootSector = (PFATX_BOOTSECTOR)BootSector;
 
    // Get the FAT type
    Volume->FatType = FatDetermineFatType(FatVolumeBootSector, PartitionSectorCount);
 
    // Dump boot sector (and swap it for big endian systems)
    TRACE("Dumping boot sector:\n");
    if (ISFATX(Volume->FatType))
    {
        FatSwapFatXBootSector(FatXVolumeBootSector);
        TRACE("sizeof(FATX_BOOTSECTOR) = 0x%x.\n", sizeof(FATX_BOOTSECTOR));
 
        TRACE("FileSystemType: %c%c%c%c.\n", FatXVolumeBootSector->FileSystemType[0], FatXVolumeBootSector->FileSystemType[1], FatXVolumeBootSector->FileSystemType[2], FatXVolumeBootSector->FileSystemType[3]);
        TRACE("VolumeSerialNumber: 0x%x\n", FatXVolumeBootSector->VolumeSerialNumber);
        TRACE("SectorsPerCluster: %d\n", FatXVolumeBootSector->SectorsPerCluster);
        TRACE("NumberOfFats: %d\n", FatXVolumeBootSector->NumberOfFats);
        TRACE("Unknown: 0x%x\n", FatXVolumeBootSector->Unknown);
 
        TRACE("FatType %s\n", Volume->FatType == FATX16 ? "FATX16" : "FATX32");
 
    }
    else if (Volume->FatType == FAT32)
    {
        FatSwapFat32BootSector(Fat32VolumeBootSector);
        TRACE("sizeof(FAT32_BOOTSECTOR) = 0x%x.\n", sizeof(FAT32_BOOTSECTOR));
 
        TRACE("JumpBoot: 0x%x 0x%x 0x%x\n", Fat32VolumeBootSector->JumpBoot[0], Fat32VolumeBootSector->JumpBoot[1], Fat32VolumeBootSector->JumpBoot[2]);
        TRACE("OemName: %c%c%c%c%c%c%c%c\n", Fat32VolumeBootSector->OemName[0], Fat32VolumeBootSector->OemName[1], Fat32VolumeBootSector->OemName[2], Fat32VolumeBootSector->OemName[3], Fat32VolumeBootSector->OemName[4], Fat32VolumeBootSector->OemName[5], Fat32VolumeBootSector->OemName[6], Fat32VolumeBootSector->OemName[7]);
        TRACE("BytesPerSector: %d\n", Fat32VolumeBootSector->BytesPerSector);
        TRACE("SectorsPerCluster: %d\n", Fat32VolumeBootSector->SectorsPerCluster);
        TRACE("ReservedSectors: %d\n", Fat32VolumeBootSector->ReservedSectors);
        TRACE("NumberOfFats: %d\n", Fat32VolumeBootSector->NumberOfFats);
        TRACE("RootDirEntries: %d\n", Fat32VolumeBootSector->RootDirEntries);
        TRACE("TotalSectors: %d\n", Fat32VolumeBootSector->TotalSectors);
        TRACE("MediaDescriptor: 0x%x\n", Fat32VolumeBootSector->MediaDescriptor);
        TRACE("SectorsPerFat: %d\n", Fat32VolumeBootSector->SectorsPerFat);
        TRACE("SectorsPerTrack: %d\n", Fat32VolumeBootSector->SectorsPerTrack);
        TRACE("NumberOfHeads: %d\n", Fat32VolumeBootSector->NumberOfHeads);
        TRACE("HiddenSectors: %d\n", Fat32VolumeBootSector->HiddenSectors);
        TRACE("TotalSectorsBig: %d\n", Fat32VolumeBootSector->TotalSectorsBig);
        TRACE("SectorsPerFatBig: %d\n", Fat32VolumeBootSector->SectorsPerFatBig);
        TRACE("ExtendedFlags: 0x%x\n", Fat32VolumeBootSector->ExtendedFlags);
        TRACE("FileSystemVersion: 0x%x\n", Fat32VolumeBootSector->FileSystemVersion);
        TRACE("RootDirStartCluster: %d\n", Fat32VolumeBootSector->RootDirStartCluster);
        TRACE("FsInfo: %d\n", Fat32VolumeBootSector->FsInfo);
        TRACE("BackupBootSector: %d\n", Fat32VolumeBootSector->BackupBootSector);
        TRACE("Reserved: 0x%x\n", Fat32VolumeBootSector->Reserved);
        TRACE("DriveNumber: 0x%x\n", Fat32VolumeBootSector->DriveNumber);
        TRACE("Reserved1: 0x%x\n", Fat32VolumeBootSector->Reserved1);
        TRACE("BootSignature: 0x%x\n", Fat32VolumeBootSector->BootSignature);
        TRACE("VolumeSerialNumber: 0x%x\n", Fat32VolumeBootSector->VolumeSerialNumber);
        TRACE("VolumeLabel: %c%c%c%c%c%c%c%c%c%c%c\n", Fat32VolumeBootSector->VolumeLabel[0], Fat32VolumeBootSector->VolumeLabel[1], Fat32VolumeBootSector->VolumeLabel[2], Fat32VolumeBootSector->VolumeLabel[3], Fat32VolumeBootSector->VolumeLabel[4], Fat32VolumeBootSector->VolumeLabel[5], Fat32VolumeBootSector->VolumeLabel[6], Fat32VolumeBootSector->VolumeLabel[7], Fat32VolumeBootSector->VolumeLabel[8], Fat32VolumeBootSector->VolumeLabel[9], Fat32VolumeBootSector->VolumeLabel[10]);
        TRACE("FileSystemType: %c%c%c%c%c%c%c%c\n", Fat32VolumeBootSector->FileSystemType[0], Fat32VolumeBootSector->FileSystemType[1], Fat32VolumeBootSector->FileSystemType[2], Fat32VolumeBootSector->FileSystemType[3], Fat32VolumeBootSector->FileSystemType[4], Fat32VolumeBootSector->FileSystemType[5], Fat32VolumeBootSector->FileSystemType[6], Fat32VolumeBootSector->FileSystemType[7]);
        TRACE("BootSectorMagic: 0x%x\n", Fat32VolumeBootSector->BootSectorMagic);
    }
    else
    {
        FatSwapFatBootSector(FatVolumeBootSector);
        TRACE("sizeof(FAT_BOOTSECTOR) = 0x%x.\n", sizeof(FAT_BOOTSECTOR));
 
        TRACE("JumpBoot: 0x%x 0x%x 0x%x\n", FatVolumeBootSector->JumpBoot[0], FatVolumeBootSector->JumpBoot[1], FatVolumeBootSector->JumpBoot[2]);
        TRACE("OemName: %c%c%c%c%c%c%c%c\n", FatVolumeBootSector->OemName[0], FatVolumeBootSector->OemName[1], FatVolumeBootSector->OemName[2], FatVolumeBootSector->OemName[3], FatVolumeBootSector->OemName[4], FatVolumeBootSector->OemName[5], FatVolumeBootSector->OemName[6], FatVolumeBootSector->OemName[7]);
        TRACE("BytesPerSector: %d\n", FatVolumeBootSector->BytesPerSector);
        TRACE("SectorsPerCluster: %d\n", FatVolumeBootSector->SectorsPerCluster);
        TRACE("ReservedSectors: %d\n", FatVolumeBootSector->ReservedSectors);
        TRACE("NumberOfFats: %d\n", FatVolumeBootSector->NumberOfFats);
        TRACE("RootDirEntries: %d\n", FatVolumeBootSector->RootDirEntries);
        TRACE("TotalSectors: %d\n", FatVolumeBootSector->TotalSectors);
        TRACE("MediaDescriptor: 0x%x\n", FatVolumeBootSector->MediaDescriptor);
        TRACE("SectorsPerFat: %d\n", FatVolumeBootSector->SectorsPerFat);
        TRACE("SectorsPerTrack: %d\n", FatVolumeBootSector->SectorsPerTrack);
        TRACE("NumberOfHeads: %d\n", FatVolumeBootSector->NumberOfHeads);
        TRACE("HiddenSectors: %d\n", FatVolumeBootSector->HiddenSectors);
        TRACE("TotalSectorsBig: %d\n", FatVolumeBootSector->TotalSectorsBig);
        TRACE("DriveNumber: 0x%x\n", FatVolumeBootSector->DriveNumber);
        TRACE("Reserved1: 0x%x\n", FatVolumeBootSector->Reserved1);
        TRACE("BootSignature: 0x%x\n", FatVolumeBootSector->BootSignature);
        TRACE("VolumeSerialNumber: 0x%x\n", FatVolumeBootSector->VolumeSerialNumber);
        TRACE("VolumeLabel: %c%c%c%c%c%c%c%c%c%c%c\n", FatVolumeBootSector->VolumeLabel[0], FatVolumeBootSector->VolumeLabel[1], FatVolumeBootSector->VolumeLabel[2], FatVolumeBootSector->VolumeLabel[3], FatVolumeBootSector->VolumeLabel[4], FatVolumeBootSector->VolumeLabel[5], FatVolumeBootSector->VolumeLabel[6], FatVolumeBootSector->VolumeLabel[7], FatVolumeBootSector->VolumeLabel[8], FatVolumeBootSector->VolumeLabel[9], FatVolumeBootSector->VolumeLabel[10]);
        TRACE("FileSystemType: %c%c%c%c%c%c%c%c\n", FatVolumeBootSector->FileSystemType[0], FatVolumeBootSector->FileSystemType[1], FatVolumeBootSector->FileSystemType[2], FatVolumeBootSector->FileSystemType[3], FatVolumeBootSector->FileSystemType[4], FatVolumeBootSector->FileSystemType[5], FatVolumeBootSector->FileSystemType[6], FatVolumeBootSector->FileSystemType[7]);
        TRACE("BootSectorMagic: 0x%x\n", FatVolumeBootSector->BootSectorMagic);
    }
 
    //
    // Check the boot sector magic
    //
    if (! ISFATX(Volume->FatType) && FatVolumeBootSector->BootSectorMagic != 0xaa55)
    {
        sprintf(ErrMsg, "Invalid boot sector magic (expected 0xaa55 found 0x%x)",
                FatVolumeBootSector->BootSectorMagic);
        FileSystemError(ErrMsg);
        return FALSE;
    }
 
    //
    // Check the FAT cluster size
    // We do not support clusters bigger than 64k
    //
    if ((ISFATX(Volume->FatType) && 64 * 1024 < FatXVolumeBootSector->SectorsPerCluster * 512) ||
       (! ISFATX(Volume->FatType) && 64 * 1024 < FatVolumeBootSector->SectorsPerCluster * FatVolumeBootSector->BytesPerSector))
    {
        FileSystemError("This file system has cluster sizes bigger than 64k.\nFreeLoader does not support this.");
        return FALSE;
    }
 
    if (ISFATX(Volume->FatType))
    {
        Volume->TotalSectors = PartitionSectorCount;
    }
    else
    {
        /*
         * After DOS 4.0, at least one of TotalSectors or TotalSectorsBig will be zero.
         * In DOS version 3.2 or before, both of these might contain some value,
         * because, before 3.2, there was no TotalSectorsBig entry. Thus some disks
         * might have an unexpected value in the field, and we will use TotalSectorsBig
         * only if TotalSectors equals zero.
         */
        C_ASSERT(FIELD_OFFSET(FAT_BOOTSECTOR, TotalSectors) ==
                 FIELD_OFFSET(FAT32_BOOTSECTOR, TotalSectors));
        C_ASSERT(FIELD_OFFSET(FAT_BOOTSECTOR, TotalSectorsBig) ==
                 FIELD_OFFSET(FAT32_BOOTSECTOR, TotalSectorsBig));
        Volume->TotalSectors = (FatVolumeBootSector->TotalSectors ? FatVolumeBootSector->TotalSectors
                                                                  : FatVolumeBootSector->TotalSectorsBig);
    }
 
    /* Get the sectors per FAT, root directory sector start, and data sector start */
    if (ISFATX(Volume->FatType))
    {
        Volume->BytesPerSector = SECTOR_SIZE;
        Volume->SectorsPerCluster = SWAPD(FatXVolumeBootSector->SectorsPerCluster);
        Volume->FatSectorStart = 4096 / Volume->BytesPerSector;
        Volume->ActiveFatSectorStart = Volume->FatSectorStart;
        Volume->NumberOfFats = 1; // FatXVolumeBootSector->NumberOfFats;
        FatSize = (ULONG)(PartitionSectorCount / Volume->SectorsPerCluster *
                  (Volume->FatType == FATX16 ? 2 : 4));
        Volume->SectorsPerFat = ROUND_UP(FatSize, 4096) / Volume->BytesPerSector;
 
        Volume->RootDirSectorStart = Volume->FatSectorStart + Volume->NumberOfFats * Volume->SectorsPerFat;
        Volume->RootDirSectors = FatXVolumeBootSector->SectorsPerCluster;
 
        Volume->DataSectorStart = Volume->RootDirSectorStart + Volume->RootDirSectors;
    }
    else if (Volume->FatType != FAT32)
    {
        Volume->BytesPerSector = FatVolumeBootSector->BytesPerSector;
        Volume->SectorsPerCluster = FatVolumeBootSector->SectorsPerCluster;
        Volume->FatSectorStart = FatVolumeBootSector->ReservedSectors;
        Volume->ActiveFatSectorStart = Volume->FatSectorStart;
        Volume->NumberOfFats = FatVolumeBootSector->NumberOfFats;
        Volume->SectorsPerFat = FatVolumeBootSector->SectorsPerFat;
 
        Volume->RootDirSectorStart = Volume->FatSectorStart + Volume->NumberOfFats * Volume->SectorsPerFat;
        Volume->RootDirSectors = ((FatVolumeBootSector->RootDirEntries * 32) + (Volume->BytesPerSector - 1)) / Volume->BytesPerSector;
        // Volume->RootDirSectors = (FatVolumeBootSector->RootDirEntries * sizeof(DIRENT) / Volume->BytesPerSector);
 
        Volume->DataSectorStart = Volume->RootDirSectorStart + Volume->RootDirSectors;
    }
    else
    {
        Volume->BytesPerSector = Fat32VolumeBootSector->BytesPerSector;
        Volume->SectorsPerCluster = Fat32VolumeBootSector->SectorsPerCluster;
        Volume->FatSectorStart = Fat32VolumeBootSector->ReservedSectors;
        Volume->ActiveFatSectorStart =
            Volume->FatSectorStart + ((Fat32VolumeBootSector->ExtendedFlags & 0x80) ?
                                      ((Fat32VolumeBootSector->ExtendedFlags & 0x0f) * Fat32VolumeBootSector->SectorsPerFatBig) : 0);
        Volume->NumberOfFats = Fat32VolumeBootSector->NumberOfFats;
        Volume->SectorsPerFat = Fat32VolumeBootSector->SectorsPerFatBig;
        // Volume->SectorsPerFat = (Fat32VolumeBootSector->SectorsPerFat ? Fat32VolumeBootSector->SectorsPerFat : Fat32VolumeBootSector->SectorsPerFatBig);
 
        Volume->RootDirStartCluster = Fat32VolumeBootSector->RootDirStartCluster;
        Volume->DataSectorStart = Volume->FatSectorStart + Volume->NumberOfFats * Volume->SectorsPerFat;
 
        //
        // Check version
        // we only work with version 0
        //
        if (Fat32VolumeBootSector->FileSystemVersion != 0)
        {
            FileSystemError("FreeLoader is too old to work with this FAT32 filesystem.\nPlease update FreeLoader.");
            return FALSE;
        }
    }
    // Volume->NumberOfClusters = FatNumberOfClusters(Volume);
 
    Volume->FatCacheSize = min(Volume->SectorsPerFat, FAT_MAX_CACHE_SIZE / Volume->BytesPerSector);
    TRACE("FAT cache is %d sectors, %d bytes\n", Volume->FatCacheSize, Volume->FatCacheSize * Volume->BytesPerSector);
 
    Volume->FatCache = FrLdrTempAlloc(Volume->FatCacheSize * Volume->BytesPerSector, TAG_FAT_CACHE);
    if (!Volume->FatCache)
    {
        FileSystemError("Cannot allocate memory for FAT cache");
        return FALSE;
    }
 
    Volume->FatCacheIndex = FrLdrTempAlloc(Volume->FatCacheSize * sizeof(*Volume->FatCacheIndex), TAG_FAT_VOLUME);
    if (!Volume->FatCacheIndex)
    {
        FileSystemError("Cannot allocate memory for FAT cache index");
        FrLdrTempFree(Volume->FatCache, TAG_FAT_CACHE);
        return FALSE;
    }
 
    // read the beginning of the FAT (or the whole one) to cache
    if (!FatReadVolumeSectors(Volume, Volume->ActiveFatSectorStart, Volume->FatCacheSize, Volume->FatCache))
    {
        FileSystemError("Error when reading FAT cache");
        FrLdrTempFree(Volume->FatCache, TAG_FAT_CACHE);
        FrLdrTempFree(Volume->FatCacheIndex, TAG_FAT_VOLUME);
        return FALSE;
    }
 
    // fill the index with sector numbers
    for (i = 0; i < Volume->FatCacheSize; i++)
    {
        Volume->FatCacheIndex[i] = Volume->ActiveFatSectorStart + i;
    }
 
    return TRUE;
}

Referenced by FatMount().

FatParseShortFileName()

void FatParseShortFileName	(	PCHAR	Buffer,
		PDIRENTRY	DirEntry
	)

Definition at line 933 of file fat.c.

{
    ULONG        Idx;
 
    Idx = 0;
    RtlZeroMemory(Buffer, 13);
 
    //
    // Fixup first character
    //
    if (DirEntry->FileName[0] == 0x05)
    {
        DirEntry->FileName[0] = 0xE5;
    }
 
    //
    // Get the file name
    //
    while (Idx < 8)
    {
        if (DirEntry->FileName[Idx] == ' ')
        {
            break;
        }
 
        Buffer[Idx] = DirEntry->FileName[Idx];
        Idx++;
    }
 
    //
    // Get extension
    //
    if ((DirEntry->FileName[8] != ' '))
    {
        Buffer[Idx++] = '.';
        Buffer[Idx++] = (DirEntry->FileName[8] == ' ') ? '\0' : DirEntry->FileName[8];
        Buffer[Idx++] = (DirEntry->FileName[9] == ' ') ? '\0' : DirEntry->FileName[9];
        Buffer[Idx++] = (DirEntry->FileName[10] == ' ') ? '\0' : DirEntry->FileName[10];
    }
 
    //TRACE("FatParseShortFileName() ShortName = %s\n", Buffer);
}

Referenced by FatSearchDirectoryBufferForFile().

FatRead()

ARC_STATUS FatRead	(	ULONG	FileId,
		VOID *	Buffer,
		ULONG	N,
		ULONG *	Count
	)

Definition at line 1534 of file fat.c.

{
    PFAT_FILE_INFO FileHandle = FsGetDeviceSpecific(FileId);
    BOOLEAN Success;
 
    /* Call old read method */
    Success = FatReadFile(FileHandle, N, Count, Buffer);
    if (Success)
        return ESUCCESS;
    else
        return EIO;
}

FatReadAdjacentClusters()

static BOOLEAN FatReadAdjacentClusters ( PFAT_VOLUME_INFO  Volume, UINT32  StartClusterNumber, UINT32  MaxClusters, PVOID  Buffer, PUINT32  ClustersRead, PUINT32  LastClusterNumber  )

static

Definition at line 1144 of file fat.c.

{
    UINT32 NextClusterNumber;
    UINT32 ClustersToRead = 1;
    UINT32 PrevClusterNumber = StartClusterNumber;
    UINT32 ClusterStartSector = ((PrevClusterNumber - 2) * Volume->SectorsPerCluster) + Volume->DataSectorStart;
 
    *ClustersRead = 0;
    *LastClusterNumber = 0;
 
    if (!FatGetFatEntry(Volume, StartClusterNumber, &NextClusterNumber))
    {
        return FALSE;
    }
 
    // getting the number of adjacent clusters
    while (!FAT_IS_END_CLUSTER(NextClusterNumber) && ClustersToRead < MaxClusters && (NextClusterNumber == PrevClusterNumber + 1))
    {
        ClustersToRead++;
        PrevClusterNumber = NextClusterNumber;
        if (!FatGetFatEntry(Volume, PrevClusterNumber, &NextClusterNumber))
        {
            return FALSE;
        }
    }
 
    if (!FatReadVolumeSectors(Volume, ClusterStartSector, ClustersToRead * Volume->SectorsPerCluster, Buffer))
    {
        return FALSE;
    }
 
    *ClustersRead = ClustersToRead;
    *LastClusterNumber = NextClusterNumber;
 
    return !FAT_IS_END_CLUSTER(NextClusterNumber) && ClustersToRead < MaxClusters;
}

Referenced by FatReadClusterChain().

FatReadClusterChain()

static BOOLEAN FatReadClusterChain ( PFAT_VOLUME_INFO  Volume, UINT32  StartClusterNumber, UINT32  NumberOfClusters, PVOID  Buffer, PUINT32  LastClusterNumber  )

static

Definition at line 1192 of file fat.c.

{
    UINT32 ClustersRead, NextClusterNumber, ClustersLeft = NumberOfClusters;
 
    TRACE("FatReadClusterChain() StartClusterNumber = %d NumberOfClusters = %d Buffer = 0x%x\n", StartClusterNumber, NumberOfClusters, Buffer);
 
    ASSERT(NumberOfClusters > 0);
 
    while (FatReadAdjacentClusters(Volume, StartClusterNumber, ClustersLeft, Buffer, &ClustersRead, &NextClusterNumber))
    {
        ClustersLeft -= ClustersRead;
        Buffer = (PVOID)((ULONG_PTR)Buffer + (ClustersRead * Volume->SectorsPerCluster * Volume->BytesPerSector));
        StartClusterNumber = NextClusterNumber;
    }
 
    if (LastClusterNumber)
    {
        *LastClusterNumber = NextClusterNumber;
    }
 
    return (ClustersRead > 0);
}

Referenced by FatBufferDirectory(), and FatReadFile().

FatReadFile()

static BOOLEAN FatReadFile ( PFAT_FILE_INFO  FatFileInfo, ULONG  BytesToRead, ULONG *  BytesRead, PVOID  Buffer  )

static

Definition at line 1263 of file fat.c.

{
    PFAT_VOLUME_INFO Volume = FatFileInfo->Volume;
    UINT32 NextClusterNumber, BytesPerCluster;
 
    TRACE("FatReadFile() BytesToRead = %d Buffer = 0x%x\n", BytesToRead, Buffer);
 
    if (BytesRead != NULL)
    {
        *BytesRead = 0;
    }
 
    //
    // If the user is trying to read past the end of
    // the file then return success with BytesRead == 0.
    //
    if (FatFileInfo->FilePointer >= FatFileInfo->FileSize)
    {
        return TRUE;
    }
 
    //
    // If the user is trying to read more than there is to read
    // then adjust the amount to read.
    //
    if ((FatFileInfo->FilePointer + BytesToRead) > FatFileInfo->FileSize)
    {
        BytesToRead = (FatFileInfo->FileSize - FatFileInfo->FilePointer);
    }
 
    //
    // Ok, now we have to perform at most 3 calculations
    // I'll draw you a picture (using nifty ASCII art):
    //
    // CurrentFilePointer -+
    //                     |
    //    +----------------+
    //    |
    // +-----------+-----------+-----------+-----------+
    // | Cluster 1 | Cluster 2 | Cluster 3 | Cluster 4 |
    // +-----------+-----------+-----------+-----------+
    //    |                                    |
    //    +---------------+--------------------+
    //                    |
    // BytesToRead -------+
    //
    // 1 - The first calculation (and read) will align
    //     the file pointer with the next cluster.
    //     boundary (if we are supposed to read that much)
    // 2 - The next calculation (and read) will read
    //     in all the full clusters that the requested
    //     amount of data would cover (in this case
    //     clusters 2 & 3).
    // 3 - The last calculation (and read) would read
    //     in the remainder of the data requested out of
    //     the last cluster.
    //
 
    BytesPerCluster = Volume->SectorsPerCluster * Volume->BytesPerSector;
 
    //
    // Only do the first read if we
    // aren't aligned on a cluster boundary
    //
    if (FatFileInfo->FilePointer % BytesPerCluster)
    {
        //
        // Do the math for our first read
        //
        UINT32 OffsetInCluster = FatFileInfo->FilePointer % BytesPerCluster;
        UINT32 LengthInCluster = min(BytesToRead, BytesPerCluster - OffsetInCluster);
 
        ASSERT(LengthInCluster <= BytesPerCluster && LengthInCluster > 0);
 
        //
        // Now do the read and update BytesRead, BytesToRead, FilePointer, & Buffer
        //
        if (!FatReadPartialCluster(Volume, FatFileInfo->CurrentCluster, OffsetInCluster, LengthInCluster, Buffer))
        {
            return FALSE;
        }
        if (BytesRead != NULL)
        {
            *BytesRead += LengthInCluster;
        }
        BytesToRead -= LengthInCluster;
        FatFileInfo->FilePointer += LengthInCluster;
        Buffer = (PVOID)((ULONG_PTR)Buffer + LengthInCluster);
 
        // get the next cluster if needed
        if ((LengthInCluster + OffsetInCluster) == BytesPerCluster)
        {
            if (!FatGetFatEntry(Volume, FatFileInfo->CurrentCluster, &NextClusterNumber))
            {
                return FALSE;
            }
 
            FatFileInfo->CurrentCluster = NextClusterNumber;
            TRACE("FatReadFile() FatFileInfo->CurrentCluster = 0x%x\n", FatFileInfo->CurrentCluster);
        }
    }
 
    //
    // Do the math for our second read (if any data left)
    //
    if (BytesToRead > 0)
    {
        //
        // Determine how many full clusters we need to read
        //
        UINT32 NumberOfClusters = BytesToRead / BytesPerCluster;
 
        TRACE("Going to read: %u clusters\n", NumberOfClusters);
 
        if (NumberOfClusters > 0)
        {
            UINT32 BytesReadHere = NumberOfClusters * BytesPerCluster;
 
            ASSERT(!FAT_IS_END_CLUSTER(FatFileInfo->CurrentCluster));
 
            if (!FatReadClusterChain(Volume, FatFileInfo->CurrentCluster, NumberOfClusters, Buffer, &NextClusterNumber))
            {
                return FALSE;
            }
 
            if (BytesRead != NULL)
            {
                *BytesRead += BytesReadHere;
            }
            BytesToRead -= BytesReadHere;
            Buffer = (PVOID)((ULONG_PTR)Buffer + BytesReadHere);
 
            ASSERT(!FAT_IS_END_CLUSTER(NextClusterNumber) || BytesToRead == 0);
 
            FatFileInfo->FilePointer += BytesReadHere;
            FatFileInfo->CurrentCluster = NextClusterNumber;
            TRACE("FatReadFile() FatFileInfo->CurrentCluster = 0x%x\n", FatFileInfo->CurrentCluster);
        }
    }
 
    //
    // Do the math for our third read (if any data left)
    //
    if (BytesToRead > 0)
    {
        ASSERT(!FAT_IS_END_CLUSTER(FatFileInfo->CurrentCluster));
 
        //
        // Now do the read and update BytesRead & FilePointer
        //
        if (!FatReadPartialCluster(Volume, FatFileInfo->CurrentCluster, 0, BytesToRead, Buffer))
        {
            return FALSE;
        }
        if (BytesRead != NULL)
        {
            *BytesRead += BytesToRead;
        }
        FatFileInfo->FilePointer += BytesToRead;
    }
 
    return TRUE;
}

Referenced by FatRead().

FatReadPartialCluster()

BOOLEAN FatReadPartialCluster	(	PFAT_VOLUME_INFO	Volume,
		ULONG	ClusterNumber,
		ULONG	StartingOffset,
		ULONG	Length,
		PVOID	Buffer
	)

Definition at line 1219 of file fat.c.

{
    ULONG        ClusterStartSector;
    ULONG SectorOffset, ReadSize, SectorCount;
    PUCHAR ReadBuffer;
    BOOLEAN Success = FALSE;
 
    //TRACE("FatReadPartialCluster() ClusterNumber = %d StartingOffset = %d Length = %d Buffer = 0x%x\n", ClusterNumber, StartingOffset, Length, Buffer);
 
    ClusterStartSector = ((ClusterNumber - 2) * Volume->SectorsPerCluster) + Volume->DataSectorStart;
 
    // This is the offset of the data in sectors
    SectorOffset = (StartingOffset / Volume->BytesPerSector);
    StartingOffset %= Volume->BytesPerSector;
 
    // Calculate how many sectors we need to read
    SectorCount = (StartingOffset + Length + Volume->BytesPerSector - 1) / Volume->BytesPerSector;
 
    // Calculate rounded up read size
    ReadSize = SectorCount * Volume->BytesPerSector;
 
    ReadBuffer = FrLdrTempAlloc(ReadSize, TAG_FAT_BUFFER);
    if (!ReadBuffer)
    {
        return FALSE;
    }
 
    if (FatReadVolumeSectors(Volume, ClusterStartSector + SectorOffset, SectorCount, ReadBuffer))
    {
        RtlCopyMemory(Buffer, ReadBuffer + StartingOffset, Length);
        Success = TRUE;
    }
 
    FrLdrTempFree(ReadBuffer, TAG_FAT_BUFFER);
 
    return Success;
}

Referenced by FatReadFile().

FatReadVolumeSectors()

BOOLEAN FatReadVolumeSectors	(	PFAT_VOLUME_INFO	Volume,
		ULONG	SectorNumber,
		ULONG	SectorCount,
		PVOID	Buffer
	)

Definition at line 1427 of file fat.c.

{
    LARGE_INTEGER Position;
    ULONG Count;
    ARC_STATUS Status;
 
    //TRACE("FatReadVolumeSectors(): SectorNumber %d, SectorCount %d, Buffer %p\n",
    //    SectorNumber, SectorCount, Buffer);
 
    //
    // Seek to right position
    //
    Position.QuadPart = (ULONGLONG)SectorNumber * Volume->BytesPerSector;
    Status = ArcSeek(Volume->DeviceId, &Position, SeekAbsolute);
    if (Status != ESUCCESS)
    {
        TRACE("FatReadVolumeSectors() Failed to seek\n");
        return FALSE;
    }
 
    //
    // Read data
    //
    Status = ArcRead(Volume->DeviceId, Buffer, SectorCount * Volume->BytesPerSector, &Count);
    if (Status != ESUCCESS || Count != SectorCount * Volume->BytesPerSector)
    {
        TRACE("FatReadVolumeSectors() Failed to read\n");
        return FALSE;
    }
 
    // Return success
    return TRUE;
}

Referenced by FatBufferDirectory(), FatGetFatSector(), FatOpenVolume(), FatReadAdjacentClusters(), and FatReadPartialCluster().

FatSearchDirectoryBufferForFile()

static BOOLEAN FatSearchDirectoryBufferForFile ( PFAT_VOLUME_INFO  Volume, PVOID  DirectoryBuffer, ULONG  DirectorySize, PCHAR  FileName, PFAT_FILE_INFO  FatFileInfoPointer  )

static

Definition at line 549 of file fat.c.

{
    ULONG        EntryCount;
    ULONG        CurrentEntry;
    CHAR        LfnNameBuffer[265];
    CHAR        ShortNameBuffer[20];
    ULONG        StartCluster;
    DIRENTRY        OurDirEntry;
    LFN_DIRENTRY    OurLfnDirEntry;
    PDIRENTRY    DirEntry = &OurDirEntry;
    PLFN_DIRENTRY    LfnDirEntry = &OurLfnDirEntry;
 
    EntryCount = DirectorySize / sizeof(DIRENTRY);
 
    TRACE("FatSearchDirectoryBufferForFile() DirectoryBuffer = 0x%x EntryCount = %d FileName = %s\n", DirectoryBuffer, EntryCount, FileName);
 
    RtlZeroMemory(ShortNameBuffer, 13 * sizeof(CHAR));
    RtlZeroMemory(LfnNameBuffer, 261 * sizeof(CHAR));
 
    for (CurrentEntry=0; CurrentEntry<EntryCount; CurrentEntry++, DirectoryBuffer = ((PDIRENTRY)DirectoryBuffer)+1)
    {
        OurLfnDirEntry = *((PLFN_DIRENTRY) DirectoryBuffer);
        FatSwapLFNDirEntry(LfnDirEntry);
        OurDirEntry = *((PDIRENTRY) DirectoryBuffer);
        FatSwapDirEntry(DirEntry);
 
        //TRACE("Dumping directory entry %d:\n", CurrentEntry);
        //DbgDumpBuffer(DPRINT_FILESYSTEM, DirEntry, sizeof(DIRENTRY));
 
        //
        // Check if this is the last file in the directory
        // If DirEntry[0] == 0x00 then that means all the
        // entries after this one are unused. If this is the
        // last entry then we didn't find the file in this directory.
        //
        if (DirEntry->FileName[0] == '\0')
        {
            return FALSE;
        }
 
        //
        // Check if this is a deleted entry or not
        //
        if (DirEntry->FileName[0] == '\xE5')
        {
            RtlZeroMemory(ShortNameBuffer, 13 * sizeof(CHAR));
            RtlZeroMemory(LfnNameBuffer, 261 * sizeof(CHAR));
            continue;
        }
 
        //
        // Check if this is a LFN entry
        // If so it needs special handling
        //
        if (DirEntry->Attr == FAT_ATTR_LONG_NAME)
        {
            //
            // Check to see if this is a deleted LFN entry, if so continue
            //
            if (LfnDirEntry->SequenceNumber & 0x80)
            {
                continue;
            }
 
            //
            // Mask off high two bits of sequence number
            // and make the sequence number zero-based
            //
            LfnDirEntry->SequenceNumber &= 0x3F;
            LfnDirEntry->SequenceNumber--;
 
            //
            // Get all 13 LFN entry characters
            //
            if (LfnDirEntry->Name0_4[0] != 0xFFFF)
            {
                LfnNameBuffer[0 + (LfnDirEntry->SequenceNumber * 13)] = (UCHAR)LfnDirEntry->Name0_4[0];
            }
            if (LfnDirEntry->Name0_4[1] != 0xFFFF)
            {
                LfnNameBuffer[1 + (LfnDirEntry->SequenceNumber * 13)] = (UCHAR)LfnDirEntry->Name0_4[1];
            }
            if (LfnDirEntry->Name0_4[2] != 0xFFFF)
            {
                LfnNameBuffer[2 + (LfnDirEntry->SequenceNumber * 13)] = (UCHAR)LfnDirEntry->Name0_4[2];
            }
            if (LfnDirEntry->Name0_4[3] != 0xFFFF)
            {
                LfnNameBuffer[3 + (LfnDirEntry->SequenceNumber * 13)] = (UCHAR)LfnDirEntry->Name0_4[3];
            }
            if (LfnDirEntry->Name0_4[4] != 0xFFFF)
            {
                LfnNameBuffer[4 + (LfnDirEntry->SequenceNumber * 13)] = (UCHAR)LfnDirEntry->Name0_4[4];
            }
            if (LfnDirEntry->Name5_10[0] != 0xFFFF)
            {
                LfnNameBuffer[5 + (LfnDirEntry->SequenceNumber * 13)] = (UCHAR)LfnDirEntry->Name5_10[0];
            }
            if (LfnDirEntry->Name5_10[1] != 0xFFFF)
            {
                LfnNameBuffer[6 + (LfnDirEntry->SequenceNumber * 13)] = (UCHAR)LfnDirEntry->Name5_10[1];
            }
            if (LfnDirEntry->Name5_10[2] != 0xFFFF)
            {
                LfnNameBuffer[7 + (LfnDirEntry->SequenceNumber * 13)] = (UCHAR)LfnDirEntry->Name5_10[2];
            }
            if (LfnDirEntry->Name5_10[3] != 0xFFFF)
            {
                LfnNameBuffer[8 + (LfnDirEntry->SequenceNumber * 13)] = (UCHAR)LfnDirEntry->Name5_10[3];
            }
            if (LfnDirEntry->Name5_10[4] != 0xFFFF)
            {
                LfnNameBuffer[9 + (LfnDirEntry->SequenceNumber * 13)] = (UCHAR)LfnDirEntry->Name5_10[4];
            }
            if (LfnDirEntry->Name5_10[5] != 0xFFFF)
            {
                LfnNameBuffer[10 + (LfnDirEntry->SequenceNumber * 13)] = (UCHAR)LfnDirEntry->Name5_10[5];
            }
            if (LfnDirEntry->Name11_12[0] != 0xFFFF)
            {
                LfnNameBuffer[11 + (LfnDirEntry->SequenceNumber * 13)] = (UCHAR)LfnDirEntry->Name11_12[0];
            }
            if (LfnDirEntry->Name11_12[1] != 0xFFFF)
            {
                LfnNameBuffer[12 + (LfnDirEntry->SequenceNumber * 13)] = (UCHAR)LfnDirEntry->Name11_12[1];
            }
 
            //TRACE("Dumping long name buffer:\n");
            //DbgDumpBuffer(DPRINT_FILESYSTEM, LfnNameBuffer, 260);
 
            continue;
        }
 
        //
        // Check for the volume label attribute
        // and skip over this entry if found
        //
        if (DirEntry->Attr & FAT_ATTR_VOLUMENAME)
        {
            RtlZeroMemory(ShortNameBuffer, 13 * sizeof(UCHAR));
            RtlZeroMemory(LfnNameBuffer, 261 * sizeof(UCHAR));
            continue;
        }
 
        //
        // If we get here then we've found a short file name
        // entry and LfnNameBuffer contains the long file
        // name or zeroes. All we have to do now is see if the
        // file name matches either the short or long file name
        // and fill in the FAT_FILE_INFO structure if it does
        // or zero our buffers and continue looking.
        //
 
        //
        // Get short file name
        //
        FatParseShortFileName(ShortNameBuffer, DirEntry);
 
        //TRACE("Entry: %d LFN = %s\n", CurrentEntry, LfnNameBuffer);
        //TRACE("Entry: %d DOS name = %s\n", CurrentEntry, ShortNameBuffer);
 
        //
        // See if the file name matches either the short or long name
        //
        if ((_stricmp(FileName, LfnNameBuffer) == 0) || (_stricmp(FileName, ShortNameBuffer) == 0))
        {
            //
            // We found the entry, now fill in the FAT_FILE_INFO struct
            //
            FatFileInfoPointer->Attributes = DirEntry->Attr;
            FatFileInfoPointer->FileSize = DirEntry->Size;
            FatFileInfoPointer->FilePointer = 0;
            StartCluster = ((ULONG)DirEntry->ClusterHigh << 16) + DirEntry->ClusterLow;
            FatFileInfoPointer->CurrentCluster = StartCluster;
            FatFileInfoPointer->StartCluster = StartCluster;
 
            TRACE("MSDOS Directory Entry:\n");
            TRACE("FileName[11] = %c%c%c%c%c%c%c%c%c%c%c\n",
                  DirEntry->FileName[0], DirEntry->FileName[1], DirEntry->FileName[2], DirEntry->FileName[3], DirEntry->FileName[4],
                  DirEntry->FileName[5], DirEntry->FileName[6], DirEntry->FileName[7], DirEntry->FileName[8], DirEntry->FileName[9], DirEntry->FileName[10]);
            TRACE("Attr = 0x%x\n", DirEntry->Attr);
            TRACE("ReservedNT = 0x%x\n", DirEntry->ReservedNT);
            TRACE("TimeInTenths = %d\n", DirEntry->TimeInTenths);
            TRACE("CreateTime = %d\n", DirEntry->CreateTime);
            TRACE("CreateDate = %d\n", DirEntry->CreateDate);
            TRACE("LastAccessDate = %d\n", DirEntry->LastAccessDate);
            TRACE("ClusterHigh = 0x%x\n", DirEntry->ClusterHigh);
            TRACE("Time = %d\n", DirEntry->Time);
            TRACE("Date = %d\n", DirEntry->Date);
            TRACE("ClusterLow = 0x%x\n", DirEntry->ClusterLow);
            TRACE("Size = %d\n", DirEntry->Size);
            TRACE("StartCluster = 0x%x\n", StartCluster);
 
            return TRUE;
        }
 
        //
        // Nope, no match - zero buffers and continue looking
        //
        RtlZeroMemory(ShortNameBuffer, 13 * sizeof(UCHAR));
        RtlZeroMemory(LfnNameBuffer, 261 * sizeof(UCHAR));
    }
 
    return FALSE;
}

Referenced by FatLookupFile().

FatSeek()

ARC_STATUS FatSeek	(	ULONG	FileId,
		LARGE_INTEGER *	Position,
		SEEKMODE	SeekMode
	)

Definition at line 1547 of file fat.c.

{
    PFAT_FILE_INFO FileHandle = FsGetDeviceSpecific(FileId);
    PFAT_VOLUME_INFO Volume = FileHandle->Volume;
    LARGE_INTEGER NewPosition = *Position;
 
    switch (SeekMode)
    {
        case SeekAbsolute:
            break;
        case SeekRelative:
            NewPosition.QuadPart += (ULONGLONG)FileHandle->FilePointer;
            break;
        default:
            ASSERT(FALSE);
            return EINVAL;
    }
 
    if (NewPosition.HighPart != 0)
        return EINVAL;
    if (NewPosition.LowPart >= FileHandle->FileSize)
        return EINVAL;
 
    TRACE("FatSeek() NewPosition = %u, OldPointer = %u, SeekMode = %d\n", NewPosition.LowPart, FileHandle->FilePointer, SeekMode);
 
    {
        UINT32 OldClusterIdx = FileHandle->FilePointer / (Volume->SectorsPerCluster * Volume->BytesPerSector);
        UINT32 NewClusterIdx = NewPosition.LowPart / (Volume->SectorsPerCluster * Volume->BytesPerSector);
 
        TRACE("FatSeek() OldClusterIdx: %u, NewClusterIdx: %u\n", OldClusterIdx, NewClusterIdx);
 
        if (NewClusterIdx != OldClusterIdx)
        {
            UINT32 CurrentClusterIdx, ClusterNumber;
 
            if (NewClusterIdx > OldClusterIdx)
            {
                CurrentClusterIdx = OldClusterIdx;
                ClusterNumber = FileHandle->CurrentCluster;
            }
            else
            {
                CurrentClusterIdx = 0;
                ClusterNumber = FileHandle->StartCluster;
            }
 
            for (; CurrentClusterIdx < NewClusterIdx; CurrentClusterIdx++)
            {
                if (!FatGetFatEntry(Volume, ClusterNumber, &ClusterNumber))
                {
                    return EIO;
                }
            }
            FileHandle->CurrentCluster = ClusterNumber;
        }
    }
 
    FileHandle->FilePointer = NewPosition.LowPart;
 
    return ESUCCESS;
}

FatSwapDirEntry()

VOID FatSwapDirEntry

(

PDIRENTRY

Obj

)

Definition at line 103 of file fat.c.

{
    SW(Obj, CreateTime);
    SW(Obj, CreateDate);
    SW(Obj, LastAccessDate);
    SW(Obj, ClusterHigh);
    SW(Obj, Time);
    SW(Obj, Date);
    SW(Obj, ClusterLow);
    SD(Obj, Size);
}

Referenced by FatSearchDirectoryBufferForFile().

FatSwapFat32BootSector()

VOID FatSwapFat32BootSector

(

PFAT32_BOOTSECTOR

Obj

)

Definition at line 76 of file fat.c.

{
    SW(Obj, BytesPerSector);
    SW(Obj, ReservedSectors);
    SW(Obj, RootDirEntries);
    SW(Obj, TotalSectors);
    SW(Obj, SectorsPerFat);
    SW(Obj, NumberOfHeads);
    SD(Obj, HiddenSectors);
    SD(Obj, TotalSectorsBig);
    SD(Obj, SectorsPerFatBig);
    SW(Obj, ExtendedFlags);
    SW(Obj, FileSystemVersion);
    SD(Obj, RootDirStartCluster);
    SW(Obj, FsInfo);
    SW(Obj, BackupBootSector);
    SD(Obj, VolumeSerialNumber);
    SW(Obj, BootSectorMagic);
}

Referenced by FatOpenVolume().

FatSwapFatBootSector()

VOID FatSwapFatBootSector

(

PFAT_BOOTSECTOR

Obj

)

Definition at line 61 of file fat.c.

{
    SW(Obj, BytesPerSector);
    SW(Obj, ReservedSectors);
    SW(Obj, RootDirEntries);
    SW(Obj, TotalSectors);
    SW(Obj, SectorsPerFat);
    SW(Obj, SectorsPerTrack);
    SW(Obj, NumberOfHeads);
    SD(Obj, HiddenSectors);
    SD(Obj, TotalSectorsBig);
    SD(Obj, VolumeSerialNumber);
    SW(Obj, BootSectorMagic);
}

Referenced by FatOpenVolume().

FatSwapFatXBootSector()

VOID FatSwapFatXBootSector

(

PFATX_BOOTSECTOR

Obj

)

Definition at line 96 of file fat.c.

{
    SD(Obj, VolumeSerialNumber);
    SD(Obj, SectorsPerCluster);
    SW(Obj, NumberOfFats);
}

Referenced by FatOpenVolume().

FatSwapFatXDirEntry()

VOID FatSwapFatXDirEntry

(

PFATX_DIRENTRY

Obj

)

Definition at line 127 of file fat.c.

{
    SD(Obj, StartCluster);
    SD(Obj, Size);
    SW(Obj, Time);
    SW(Obj, Date);
    SW(Obj, CreateTime);
    SW(Obj, CreateDate);
    SW(Obj, LastAccessTime);
    SW(Obj, LastAccessDate);
}

Referenced by FatXSearchDirectoryBufferForFile().

FatSwapLFNDirEntry()

VOID FatSwapLFNDirEntry

(

PLFN_DIRENTRY

Obj

)

Definition at line 115 of file fat.c.

{
    int i;
    SW(Obj, StartCluster);
    for(i = 0; i < 5; i++)
        Obj->Name0_4[i] = SWAPW(Obj->Name0_4[i]);
    for(i = 0; i < 6; i++)
        Obj->Name5_10[i] = SWAPW(Obj->Name5_10[i]);
    for(i = 0; i < 2; i++)
        Obj->Name11_12[i] = SWAPW(Obj->Name11_12[i]);
}

Referenced by FatSearchDirectoryBufferForFile().

FatXSearchDirectoryBufferForFile()

static BOOLEAN FatXSearchDirectoryBufferForFile ( PFAT_VOLUME_INFO  Volume, PVOID  DirectoryBuffer, ULONG  DirectorySize, PCHAR  FileName, PFAT_FILE_INFO  FatFileInfoPointer  )

static

Definition at line 755 of file fat.c.

{
    ULONG        EntryCount;
    ULONG        CurrentEntry;
    SIZE_T        FileNameLen;
    FATX_DIRENTRY    OurDirEntry;
    PFATX_DIRENTRY    DirEntry = &OurDirEntry;
 
    EntryCount = DirectorySize / sizeof(FATX_DIRENTRY);
 
    TRACE("FatXSearchDirectoryBufferForFile() DirectoryBuffer = 0x%x EntryCount = %d FileName = %s\n", DirectoryBuffer, EntryCount, FileName);
 
    FileNameLen = strlen(FileName);
 
    for (CurrentEntry = 0; CurrentEntry < EntryCount; CurrentEntry++, DirectoryBuffer = ((PFATX_DIRENTRY)DirectoryBuffer)+1)
    {
        OurDirEntry = *(PFATX_DIRENTRY) DirectoryBuffer;
        FatSwapFatXDirEntry(&OurDirEntry);
        if (0xff == DirEntry->FileNameSize)
        {
            break;
        }
        if (0xe5 == DirEntry->FileNameSize)
        {
            continue;
        }
        if ((FileNameLen == DirEntry->FileNameSize) &&
            (_strnicmp(FileName, DirEntry->FileName, FileNameLen) == 0))
        {
            /*
             * We found the entry, now fill in the FAT_FILE_INFO struct
             */
            FatFileInfoPointer->Attributes = DirEntry->Attr;
            FatFileInfoPointer->FileSize = DirEntry->Size;
            FatFileInfoPointer->FilePointer = 0;
            FatFileInfoPointer->CurrentCluster = DirEntry->StartCluster;
            FatFileInfoPointer->StartCluster = DirEntry->StartCluster;
 
            TRACE("FATX Directory Entry:\n");
            TRACE("FileNameSize = %d\n", DirEntry->FileNameSize);
            TRACE("Attr = 0x%x\n", DirEntry->Attr);
            TRACE("StartCluster = 0x%x\n", DirEntry->StartCluster);
            TRACE("Size = %d\n", DirEntry->Size);
            TRACE("Time = %d\n", DirEntry->Time);
            TRACE("Date = %d\n", DirEntry->Date);
            TRACE("CreateTime = %d\n", DirEntry->CreateTime);
            TRACE("CreateDate = %d\n", DirEntry->CreateDate);
            TRACE("LastAccessTime = %d\n", DirEntry->LastAccessTime);
            TRACE("LastAccessDate = %d\n", DirEntry->LastAccessDate);
 
            return TRUE;
        }
    }
 
    return FALSE;
}

Referenced by FatLookupFile().

Variable Documentation

DirectoryBufferListHead

LIST_ENTRY DirectoryBufferListHead = {&DirectoryBufferListHead, &DirectoryBufferListHead}

Definition at line 460 of file fat.c.

Referenced by FatBufferDirectory().

FatFuncTable

const DEVVTBL FatFuncTable

Initial value:

=
{
    FatClose,
    FatGetFileInformation,
    FatOpen,
    FatRead,
    FatSeek,
    L"fastfat",
}

Definition at line 1625 of file fat.c.

Referenced by FatMount().

FatVolumes

PFAT_VOLUME_INFO FatVolumes[MAX_FDS]

Definition at line 59 of file fat.c.

Referenced by FatGetVolumeSize(), FatMount(), and FatOpen().

FatXFuncTable

const DEVVTBL FatXFuncTable

Initial value:

=
{
    FatClose,
    FatGetFileInformation,
    FatOpen,
    FatRead,
    FatSeek,
    L"vfatfs",
}

Definition at line 1635 of file fat.c.

Referenced by FatMount().