reactos/drivers/filesystems/fastfat_new/rw.c

   1 /*
   2  * PROJECT:         ReactOS FAT file system driver
   3  * LICENSE:         GPL - See COPYING in the top level directory
   4  * FILE:            drivers/filesystems/fastfat/rw.c
   5  * PURPOSE:         Read/write support
   6  * PROGRAMMERS:     Aleksey Bragin (aleksey@reactos.org)
   7  *                  Alexey Vlasov
   8  */
   9
  10 /* INCLUDES *****************************************************************/
  11
  12 #define NDEBUG
  13 #include "fastfat.h"
  14
  15 /* FUNCTIONS *****************************************************************/
  16
  17 NTSTATUS
  18 NTAPI
  19 FatiRead(PFAT_IRP_CONTEXT IrpContext)
  20 {
  21     ULONG NumberOfBytes;
  22     LARGE_INTEGER ByteOffset;
  23     PFILE_OBJECT FileObject;
  24     TYPE_OF_OPEN OpenType;
  25     PIO_STACK_LOCATION IrpSp = IrpContext->Stack;
  26     PFCB Fcb;
  27     PVCB Vcb;
  28     PCCB Ccb;
  29     PVOID Buffer;
  30     LONG BytesRead;
  31
  32     FileObject = IrpSp->FileObject;
  33     NumberOfBytes = IrpSp->Parameters.Read.Length;
  34     ByteOffset = IrpSp->Parameters.Read.ByteOffset;
  35     if (NumberOfBytes == 0)
  36     {
  37         FatCompleteRequest(IrpContext, IrpContext->Irp, STATUS_SUCCESS);
  38         return STATUS_SUCCESS;
  39     }
  40
  41     OpenType = FatDecodeFileObject(FileObject, &Vcb, &Fcb, &Ccb);
  42
  43     DPRINT1("FatiRead() Fcb %p, Name %wZ, Offset %d, Length %d, Handle %p\n",
  44         Fcb, &FileObject->FileName, ByteOffset.LowPart, NumberOfBytes, Fcb->FatHandle);
  45
  46     /* Perform actual read */
  47
  48     if (IrpContext->MinorFunction & IRP_MN_MDL)
  49     {
  50         DPRINT1("MDL read\n");
  51     }
  52     else
  53     {
  54         Buffer = FatMapUserBuffer(IrpContext->Irp);
  55         DPRINT1("Normal cached read, buffer %p\n");
  56
  57         /* Set offset */
  58         FF_Seek(Fcb->FatHandle, ByteOffset.LowPart, FF_SEEK_SET);
  59
  60         /* Read */
  61         BytesRead = FF_Read(Fcb->FatHandle, NumberOfBytes, 1, Buffer);
  62         DPRINT1("Read %d bytes\n", BytesRead);
  63
  64         /* Indicate we read requested amount of bytes */
  65         IrpContext->Irp->IoStatus.Information = BytesRead;
  66         IrpContext->Irp->IoStatus.Status = STATUS_SUCCESS;
  67     }
  68
  69     /* Complete the request */
  70     FatCompleteRequest(IrpContext, IrpContext->Irp, STATUS_SUCCESS);
  71     return STATUS_SUCCESS;
  72 }
  73
  74 NTSTATUS
  75 NTAPI
  76 FatRead(PDEVICE_OBJECT DeviceObject, PIRP Irp)
  77 {
  78     NTSTATUS Status;
  79     BOOLEAN TopLevel, CanWait;
  80     PFAT_IRP_CONTEXT IrpContext;
  81
  82     CanWait = TRUE;
  83     TopLevel = FALSE;
  84     Status = STATUS_INVALID_DEVICE_REQUEST;
  85     /* Get CanWait flag */
  86     if (IoGetCurrentIrpStackLocation(Irp)->FileObject != NULL)
  87         CanWait = IoIsOperationSynchronous(Irp);
  88
  89     /* Enter FsRtl critical region */
  90     FsRtlEnterFileSystem();
  91
  92     if (DeviceObject != FatGlobalData.DiskDeviceObject)
  93     {
  94         /* Set Top Level IRP if not set */
  95         if (IoGetTopLevelIrp() == NULL)
  96         {
  97             IoSetTopLevelIrp(Irp);
  98             TopLevel = TRUE;
  99         }
 100
 101         /* Build an irp context */
 102         IrpContext = FatBuildIrpContext(Irp, CanWait);
 103
 104         /* Perform the actual read */
 105         Status = FatiRead(IrpContext);
 106
 107         /* Restore top level Irp */
 108         if (TopLevel)
 109             IoSetTopLevelIrp(NULL);
 110     }
 111     /* Leave FsRtl critical region */
 112     FsRtlExitFileSystem();
 113
 114     DPRINT1("FatRead()\n");
 115     return Status;
 116 }
 117
 118 NTSTATUS
 119 NTAPI
 120 FatWrite(PDEVICE_OBJECT DeviceObject, PIRP Irp)
 121 {
 122     DPRINT1("FatWrite()\n");
 123     return STATUS_NOT_IMPLEMENTED;
 124 }
 125
 126