reactos/drivers/fs/ms/rw.c

   1 /* $Id: rw.c,v 1.4 2002/09/08 10:22:10 chorns Exp $
   2  *
   3  * COPYRIGHT:  See COPYING in the top level directory
   4  * PROJECT:    ReactOS kernel
   5  * FILE:       services/fs/ms/rw.c
   6  * PURPOSE:    Mailslot filesystem
   7  * PROGRAMMER: Eric Kohl <ekohl@rz-online.de>
   8  */
   9
  10 /* INCLUDES ******************************************************************/
  11
  12 #include <ddk/ntddk.h>
  13 #include <ntos/minmax.h>
  14 #include "msfs.h"
  15
  16 #define NDEBUG
  17 #include <debug.h>
  18
  19
  20 /* FUNCTIONS *****************************************************************/
  21
  22 NTSTATUS STDCALL
  23 MsfsRead(PDEVICE_OBJECT DeviceObject,
  24          PIRP Irp)
  25 {
  26    PIO_STACK_LOCATION IoStack;
  27    PFILE_OBJECT FileObject;
  28    PMSFS_MAILSLOT Mailslot;
  29    PMSFS_FCB Fcb;
  30    PMSFS_MESSAGE Message;
  31    KIRQL oldIrql;
  32    ULONG Length;
  33    ULONG LengthRead = 0;
  34    PVOID Buffer;
  35    NTSTATUS Status;
  36
  37    DPRINT("MsfsRead(DeviceObject %p Irp %p)\n", DeviceObject, Irp);
  38
  39    IoStack = IoGetCurrentIrpStackLocation (Irp);
  40    FileObject = IoStack->FileObject;
  41    Fcb = (PMSFS_FCB)FileObject->FsContext;
  42    Mailslot = Fcb->Mailslot;
  43
  44    DPRINT("MailslotName: %wZ\n", &Mailslot->Name);
  45
  46    /* reading is not permitted on client side */
  47    if (Fcb->Mailslot->ServerFcb != Fcb)
  48      {
  49         Irp->IoStatus.Status = STATUS_ACCESS_DENIED;
  50         Irp->IoStatus.Information = 0;
  51
  52         IoCompleteRequest(Irp, IO_NO_INCREMENT);
  53
  54         return(STATUS_ACCESS_DENIED);
  55      }
  56
  57    Length = IoStack->Parameters.Read.Length;
  58    if (Irp->MdlAddress)
  59      Buffer = MmGetSystemAddressForMdl (Irp->MdlAddress);
  60    else
  61      Buffer = Irp->UserBuffer;
  62
  63    Status = KeWaitForSingleObject(&Mailslot->MessageEvent,
  64                                   UserRequest,
  65                                   KernelMode,
  66                                   FALSE,
  67                                   NULL); /* FIXME: handle timeout */
  68    if ((NT_SUCCESS(Status)) && (Mailslot->MessageCount > 0))
  69      {
  70         /* copy current message into buffer */
  71         Message = CONTAINING_RECORD(Mailslot->MessageListHead.Flink,
  72                                     MSFS_MESSAGE,
  73                                     MessageListEntry);
  74         memcpy(Buffer, &Message->Buffer, min(Message->Size,Length));
  75         LengthRead = Message->Size;
  76
  77         KeAcquireSpinLock(&Mailslot->MessageListLock, &oldIrql);
  78         RemoveHeadList(&Mailslot->MessageListHead);
  79         KeReleaseSpinLock(&Mailslot->MessageListLock, oldIrql);
  80
  81         ExFreePool(Message);
  82         Mailslot->MessageCount--;
  83         if (Mailslot->MessageCount == 0)
  84           {
  85              KeClearEvent(&Mailslot->MessageEvent);
  86           }
  87      }
  88
  89    Irp->IoStatus.Status = Status;
  90    Irp->IoStatus.Information = LengthRead;
  91
  92    IoCompleteRequest(Irp, IO_NO_INCREMENT);
  93
  94    return(Status);
  95 }
  96
  97
  98 NTSTATUS STDCALL
  99 MsfsWrite(PDEVICE_OBJECT DeviceObject,
 100           PIRP Irp)
 101 {
 102    PIO_STACK_LOCATION IoStack;
 103    PFILE_OBJECT FileObject;
 104    PMSFS_MAILSLOT Mailslot;
 105    PMSFS_FCB Fcb;
 106    PMSFS_MESSAGE Message;
 107    KIRQL oldIrql;
 108    ULONG Length;
 109    PVOID Buffer;
 110
 111    DPRINT("MsfsWrite(DeviceObject %p Irp %p)\n", DeviceObject, Irp);
 112
 113    IoStack = IoGetCurrentIrpStackLocation (Irp);
 114    FileObject = IoStack->FileObject;
 115    Fcb = (PMSFS_FCB)FileObject->FsContext;
 116    Mailslot = Fcb->Mailslot;
 117
 118    DPRINT("MailslotName: %wZ\n", &Mailslot->Name);
 119
 120    /* writing is not permitted on server side */
 121    if (Fcb->Mailslot->ServerFcb == Fcb)
 122      {
 123         Irp->IoStatus.Status = STATUS_ACCESS_DENIED;
 124         Irp->IoStatus.Information = 0;
 125
 126         IoCompleteRequest(Irp, IO_NO_INCREMENT);
 127
 128         return(STATUS_ACCESS_DENIED);
 129      }
 130
 131    Length = IoStack->Parameters.Write.Length;
 132    if (Irp->MdlAddress)
 133      Buffer = MmGetSystemAddressForMdl (Irp->MdlAddress);
 134    else
 135      Buffer = Irp->UserBuffer;
 136
 137    DPRINT("Length: %lu Message: %s\n", Length, (PUCHAR)Buffer);
 138
 139    /* Allocate new message */
 140    Message = ExAllocatePool(NonPagedPool,
 141                             sizeof(MSFS_MESSAGE) + Length);
 142    if (Message == NULL)
 143      {
 144         Irp->IoStatus.Status = STATUS_NO_MEMORY;
 145         Irp->IoStatus.Information = 0;
 146
 147         IoCompleteRequest(Irp, IO_NO_INCREMENT);
 148
 149         return(STATUS_NO_MEMORY);
 150      }
 151
 152    Message->Size = Length;
 153    memcpy(&Message->Buffer, Buffer, Length);
 154
 155    KeAcquireSpinLock(&Mailslot->MessageListLock, &oldIrql);
 156    InsertTailList(&Mailslot->MessageListHead, &Message->MessageListEntry);
 157    KeReleaseSpinLock(&Mailslot->MessageListLock, oldIrql);
 158
 159    Mailslot->MessageCount++;
 160    if (Mailslot->MessageCount == 1)
 161      {
 162         KeSetEvent(&Mailslot->MessageEvent,
 163                    0,
 164                    FALSE);
 165      }
 166
 167    Irp->IoStatus.Status = STATUS_SUCCESS;
 168    Irp->IoStatus.Information = Length;
 169
 170    IoCompleteRequest(Irp, IO_NO_INCREMENT);
 171
 172    return(STATUS_SUCCESS);
 173 }
 174
 175 /* EOF */