Windows NT Driver >> C/C++

StartIO

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參考資訊：
1. Source Code

StartIO提供一個序列化的機制，讓使用者可以依照順序處理IRP，這個機制對於某些只能序列執行的硬體相當有幫助，省去用軟體實現序列化的程式碼，使用的步驟：
1. IoMarkIrpPending()
2. IoStartNextPacket()

main.c

#include <wdm.h>

#define DEV_NAME L"\\Device\\MyDriver"
#define SYM_NAME L"\\DosDevices\\MyDriver"

char szBuffer[255]={0};

VOID StartIo(struct _DEVICE_OBJECT *pOurDevice, struct _IRP *pIrp)
{
  ULONG dwLen=0;
  PIO_STACK_LOCATION psk = IoGetCurrentIrpStackLocation(pIrp);
  switch(psk->MajorFunction){
  case IRP_MJ_READ:
    dwLen = strlen(szBuffer)+1;
    strcpy(pIrp->AssociatedIrp.SystemBuffer, szBuffer);
    DbgPrint("StartIo, IRP_MJ_READ");
    break;
  case IRP_MJ_WRITE:
    dwLen = psk->Parameters.Write.Length;
    strcpy(szBuffer, pIrp->AssociatedIrp.SystemBuffer);
    DbgPrint("StartIo, IRP_MJ_WRITE");
    DbgPrint("Buffer: %s, Length: %d", szBuffer, dwLen);
    break;
  }
  pIrp->IoStatus.Status = STATUS_SUCCESS;
  pIrp->IoStatus.Information = dwLen;
  IoCompleteRequest(pIrp, IO_NO_INCREMENT);
  IoStartNextPacket(pOurDevice, FALSE);
}

void Unload(PDRIVER_OBJECT pOurDriver)
{
  UNICODE_STRING usSymboName;
              
  RtlInitUnicodeString(&usSymboName, L"\\DosDevices\\MyDriver");
  IoDeleteSymbolicLink(&usSymboName);
  IoDeleteDevice(pOurDriver->DeviceObject);
}

NTSTATUS IrpFile(PDEVICE_OBJECT pOurDevice, PIRP pIrp)
{
  PIO_STACK_LOCATION psk = IoGetCurrentIrpStackLocation(pIrp);

  switch(psk->MajorFunction){
  case IRP_MJ_CREATE:
    DbgPrint("IRP_MJ_CREATE");
    break;
  case IRP_MJ_WRITE:
    DbgPrint("IrpFile, IRP_MJ_WRITE");
    IoMarkIrpPending(pIrp);
    IoStartPacket(pOurDevice, pIrp, 0, NULL);
    return STATUS_PENDING;
  case IRP_MJ_READ:
    DbgPrint("IrpFile, IRP_MJ_READ");
    IoMarkIrpPending(pIrp);
    IoStartPacket(pOurDevice, pIrp, 0, NULL);
    return STATUS_PENDING;
  case IRP_MJ_CLOSE:
    DbgPrint("IRP_MJ_CLOSE");
    break;
  }
  IoCompleteRequest(pIrp, IO_NO_INCREMENT);
  return STATUS_SUCCESS;
}

NTSTATUS DriverEntry(PDRIVER_OBJECT pOurDriver, PUNICODE_STRING pOurRegistry)
{
  PDEVICE_OBJECT pOurDevice=NULL;
  UNICODE_STRING usDeviceName;
  UNICODE_STRING usSymboName;
         
  pOurDriver->MajorFunction[IRP_MJ_CREATE] =
  pOurDriver->MajorFunction[IRP_MJ_WRITE] =
  pOurDriver->MajorFunction[IRP_MJ_READ] =
  pOurDriver->MajorFunction[IRP_MJ_CLOSE] = IrpFile;
  pOurDriver->DriverStartIo = StartIo;
  pOurDriver->DriverUnload = Unload;
           
  RtlInitUnicodeString(&usDeviceName, L"\\Device\\MyDriver");
  IoCreateDevice(pOurDriver, 0, &usDeviceName, FILE_DEVICE_UNKNOWN, 0, FALSE, &pOurDevice);
  RtlInitUnicodeString(&usSymboName, L"\\DosDevices\\MyDriver");
  IoCreateSymbolicLink(&usSymboName, &usDeviceName);
  pOurDevice->Flags&= ~DO_DEVICE_INITIALIZING;
  pOurDevice->Flags|= DO_BUFFERED_IO;
  return STATUS_SUCCESS;
}

IrpFile()IRP_MJ_READ和IRP_MJ_WRITE使用StartIO方式處理

app.c

#define INITGUID
#include <windows.h>
#include <winioctl.h>
#include <strsafe.h>
#include <setupapi.h>
#include <stdio.h>
#include <stdlib.h>

int __cdecl main(int argc, char* argv[])
{
  DWORD len=0;
  DWORD dwRet=0;
  HANDLE hFile=NULL;
  char szBuffer[255]={0};
 
  hFile = CreateFile("\\\\.\\MyDriver", GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING, 0, NULL);
  if (hFile == INVALID_HANDLE_VALUE) {
    printf("failed to open mydriver\n");
    return -1;
  }

  sprintf_s(szBuffer, sizeof(szBuffer), "I am error");
  len = strlen(szBuffer)+1;
  printf("WR: %s\n", szBuffer);
  printf("Length: %d\n", len);
  WriteFile(hFile, szBuffer, len, &dwRet, NULL);

  memset(szBuffer, 0, sizeof(szBuffer));
  ReadFile(hFile, szBuffer, sizeof(szBuffer), &dwRet, NULL);
  printf("RD: %s\n", szBuffer);
  printf("Length: %d\n", dwRet);
  CloseHandle(hFile);
  return 0;
}

結果

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