const DEVVTBL* FatMount ( ULONG DeviceId )
Definition at line 1477 of file fat.c.
Referenced by ArcOpen().
{
    PFAT_VOLUME_INFO Volume;
    UCHAR Buffer[512];
    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;
    LONG ret;

    //
    // Allocate data for volume information
    //
    Volume = MmHeapAlloc(sizeof(FAT_VOLUME_INFO));
    if (!Volume)
        return NULL;
    RtlZeroMemory(Volume, sizeof(FAT_VOLUME_INFO));

    //
    // Read the BootSector
    //
    Position.HighPart = 0;
    Position.LowPart = 0;
    ret = ArcSeek(DeviceId, &Position, SeekAbsolute);
    if (ret != ESUCCESS)
    {
        MmHeapFree(Volume);
        return NULL;
    }
    ret = ArcRead(DeviceId, Buffer, sizeof(Buffer), &Count);
    if (ret != ESUCCESS || Count != sizeof(Buffer))
    {
        MmHeapFree(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))
    {
        MmHeapFree(Volume);
        return NULL;
    }

    //
    // Determine sector count
    //
    ret = ArcGetFileInformation(DeviceId, &FileInformation);
    if (ret != ESUCCESS)
    {
        MmHeapFree(Volume);
        return NULL;
    }
    SectorCount.HighPart = FileInformation.EndingAddress.HighPart;
    SectorCount.LowPart = FileInformation.EndingAddress.LowPart;
    SectorCount.QuadPart /= SECTOR_SIZE;

    //
    // Keep device id
    //
    Volume->DeviceId = DeviceId;

    //
    // Really open the volume
    //
    if (!FatOpenVolume(Volume, BootSector, SectorCount.QuadPart))
    {
        MmHeapFree(Volume);
        return NULL;
    }

    //
    // Remember FAT volume information
    //
    FatVolumes[DeviceId] = Volume;

    //
    // Return success
    //
    return &FatFuncTable;
}
ReactOS Development > Doxygen
