Passing data from Userland to Kernel

21 Apr 2005

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Hi All,

I am working on MAC OS 10.3.3. I want to pass the data from User space
to the kernel space. For that i am using
IOConnectMethodStructureIStructureO.

I want to pass the SCSITaskData structure to the user-client from
user-space.

My SCSITaskData Structure is as follows:

typedef struct SCSITaskData {

unsigned char CDB[16];

SCSITaskAttribute taskAttribute;

unsigned int transfercount;

UInt32 scatterGatherEntries;

struct iovec scatterGatherList[1];

}SCSITaskData;

struct iovec {

char *iov_base; /* Base address. */

size_t iov_len; /* Length. */

};

Here in the User-Client i am able to print the data by following code
snippet:

IOReturn

com_SPSOFT_driver_iSCSITargetUserClient::MyDo_Write(void *vIn, void
*vOut, void *vInCnt, void * /* vOutCnt */, void *, void *)

{

IOLog("\n####################################IN
USER-CLIENT############################################################\n");

IOReturn ret = kIOReturnSuccess;

SCSITaskData * scsitask =(SCSITaskData *) vIn;

void *pData;

IOMemoryDescriptor* memP;

IOLog("\n %x %x %x %x %x %x %x %x %x
%x",scsitask->CDB[0],scsitask->CDB[1],scsitask->CDB[2],scsitask->CDB[3],scsitask->CDB[4],scsitask->CDB[5],

scsitask->CDB[6],scsitask->CDB[7],scsitask->CDB[8],scsitask->CDB[9]);

IOLog("\n\n****************DATA IN
USER_CLIENT*************************\n\n");

IOMemoryMap *mMap = NULL;

IOReturn retWrite = kIOReturnSuccess;

IOMemoryDescriptor* mem = IOMemoryDescriptor::withRanges((IOVirtualRange
*)&scsitask->scatterGatherList,(UInt32)scsitask->scatterGatherEntries,

kIODirectionOut,fTask,true);

IOLog("\n*******************************AFTER
IOMemoryDescriptor*******************************\n");

if(!mem )

{

IOLog("\ncom_SPSOFT_driver_iSCSITargetUserClient::SPSOFT_readWrite
Unable to Map memory \n");

mem->release();

ret= kIOReturnNoMemory;

}

else

{

IOLog("\n*******************************Calling Write in
driver*******************************\n");

mem->prepare();

IOLog("\n Prepare for mem Succeded....\n");

//mMap =
mem->map(kernel_task,0,kIOMapAnywhere,0,scsitask->scatterGatherList[0].iov_len);

mMap = mem->map();

if(mMap == NULL)

{

IOLog("\n Failed to map buffer......\n");

return kIOReturnError;

}

else

{

IOLog("\n mMap = %p\n", mMap);

IOLog("\n Mapped memory block for buff successfully....\n");

void *pData = mMap->getVirtualAddress();

IOLog("\n *******************************PRINITING
PDATA=%s*******************************\n",pData);

if(pData == NULL)

{

IOLog("\n Failed to get Virtual address.....\n");

return kIOReturnError;

}

}

ret =
fProvider->SPSOFT_Write(scsitask,mem,&((SCSITaskResult*)vOut)->so,&((SCSITaskResult*)vOut)->taskResult);

IOLog("\n*******************************After Write in
driver*******************************\n");

mMap->unmap();

mMap->release();

mem->complete();

mem->release();

}

if (kIOReturnSuccess != ret) {

DEBUG_LOG("%s[%p]::%s - returning err 0x%08x", getName(), this,
__FUNCTION__, ret);

}

else

{

IOLog("\n Write Completed Successfully !!!!!!!! \n");

}

return ret;

}

Here i am getting the data in the User-Client. Even i am getting the
success for WRITE_10 SCSI command. But no data is get written on the
disk.

My Driver code snippet is as follows :

IOReturn

com_SPSOFT_driver_iscsitarget::MyDo_Write(SCSITaskData *task
,IOMemoryDescriptor* mem,SCSI_Sense_Data *senseBuffer,SCSITaskResults
*taskResult)

{

SCSIServiceResponse serviceResponse =
kSCSIServiceResponse_SERVICE_DELIVERY_OR_TARGET_FAILURE;

SCSI_Sense_Data senseBuffer_temp = { 0 };

SCSITaskIdentifier request = NULL;

IOLog("\n*******************************CALL INSIDE
DRIVER*******************************\n");

IOReturn ret = kIOReturnSuccess;

request = GetSCSITask();

IOLog("\n*****************************AFTER
GetSCSITask*****************************\n");

for(int j=0;j<10;j++)

{

IOLog(" %x",task->CDB[j]);

}

if (request == NULL)

{

IOLog("%s[%p]::%s: could not get a SCSITask.\n", getName(), this,
__FUNCTION__);

mem->release();

return kIOReturnError;

}

else

{

if (isInactive() == false)

{

ResetForNewTask(request);

bool result = false;

if(IsParameterValid(0x2a, kSCSICmdFieldMask21Bit) &&

IsParameterValid(8, kSCSICmdFieldMask1Byte) &&

IsParameterValid(0, kSCSICmdFieldMask1Byte) &&

IsMemoryDescriptorValid(mem, 8))

{

IOLog("\n*****************************IsParameterValid*****************************\n");

if(SetCommandDescriptorBlock(request,0x2a,task->CDB[1],task->CDB[2],task->CDB[3],task->CDB[4],task->CDB[5],task->CDB[6],task->CDB[7],task->CDB[8],task->CDB[9])) // ???:root:20040503// byte 5

{

if (SetDataTransferDirection(request,
kSCSIDataTransfer_FromInitiatorToTarget) &&

SetDataBuffer(request, mem) && SetRequestedDataTransferCount(request,
task->transfercount * 512))

{

IOLog("\n****************************result =
true******************************\n");

result = true;

}

if(result == true)

{

serviceResponse =
kSCSIServiceResponse_SERVICE_DELIVERY_OR_TARGET_FAILURE;

IOLog("\n B4 Write \n");

IOLog("\n****************************B4
Write******************************\n");

serviceResponse= SendCommand(request, 0 );

IOLog("\n After Write \n");

IOLog("\n****************************After
Write******************************\n");

taskResult->serviceResponse = GetServiceResponse (request );

taskResult->taskStatus = GetTaskStatus ( request);

if (serviceResponse == kSCSIServiceResponse_TASK_COMPLETE)

{

bool validSense = false;

senseBuffer->SENSE_KEY=0;

senseBuffer->ADDITIONAL_SENSE_CODE=0;

senseBuffer->ADDITIONAL_SENSE_CODE_QUALIFIER=0;

if (taskResult->taskStatus == kSCSITaskStatus_CHECK_CONDITION)

{

validSense = GetAutoSenseData(request, &senseBuffer_temp,
sizeof(senseBuffer_temp));

if (validSense == false)

{

ResetForNewTask(request);

IOMemoryDescriptor* senseBufferDesc =

IOMemoryDescriptor::withAddress(&senseBuffer_temp, kSenseDefaultSize,
kIODirectionIn);

if (REQUEST_SENSE(request,senseBufferDesc,kSenseDefaultSize,0))

{

serviceResponse = SendCommand(request, 0);

}

senseBufferDesc->release();

}

}

else

{

/// NO CHECK CONDITION

}

senseBuffer->SENSE_KEY=senseBuffer_temp.SENSE_KEY;

senseBuffer->ADDITIONAL_SENSE_CODE=senseBuffer_temp.ADDITIONAL_SENSE_CODE;

senseBuffer->ADDITIONAL_SENSE_CODE_QUALIFIER=senseBuffer_temp.ADDITIONAL_SENSE_CODE_QUALIFIER;

}

else

{

// Request has a responce other than kSCSIServiceResponse_TASK_COMPLETE

}

}

else

{

mem->release();

return kIOReturnError;

}

}

else

{

mem->release();

return kIOReturnError;

}

}

else

{

mem->release();

return kIOReturnError;

}

}

ReleaseSCSITask(request);

request = NULL;

}

return kIOReturnSuccess;

}

I am writting on the specified LBA, and reading those contents using dd.
But no data is get written.

Do i need to do some other things like vm_allocate(),
mach_make_memory_entry() etc?

Please help me out. It would be a great Help.

Thank You

Kaushik

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Passing data from Userland to Kernel

pratik