WdfRequestRetrieveInputBuffer - NtDoc
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// wdfrequest.h
NTSTATUS WdfRequestRetrieveInputBuffer(
[in] WDFREQUEST Request,
size_t MinimumRequiredLength,
[out] PVOID *Buffer,
[out, optional] size_t *Length
);
View the official Windows Driver Kit DDI referenceNo description available.
[Applies to KMDF and UMDF]
The WdfRequestRetrieveInputBuffer method retrieves an I/O request's input buffer.
Request [in]A handle to a framework request object.
MinimumRequiredLengthThe minimum buffer size, in bytes, that the driver needs to process the I/O request.
Buffer [out]A pointer to a location that receives the buffer's address.
Length [out, optional]A pointer to a location that receives the buffer's size, in bytes. This parameter is optional and can be NULL.
WdfRequestRetrieveInputBuffer returns STATUS_SUCCESS if the operation succeeds. Otherwise, this method might return one of the following values:
| Return code | Description |
|---|---|
| STATUS_INVALID_PARAMETER | An input parameter is invalid. |
| STATUS_BUFFER_TOO_SMALL | The input buffer's length is zero, or the MinimumRequiredSize parameter specifies a buffer size that is larger than the buffer's actual size. |
| STATUS_INVALID_DEVICE_REQUEST | The request type is not valid or the request is using neither buffered nor direct I/O. For more information about supported methods for accessing data buffers, see the following Remarks section. |
| STATUS_INTERNAL_ERROR | The request has already been completed. |
| STATUS_INSUFFICIENT_RESOURCES | There is insufficient memory. |
This method might also return other NTSTATUS values.
A bug check occurs if the driver supplies an invalid object handle.
A request's input buffer contains information, such as data to be written to a disk, that was supplied by the originator of the request. Your driver can call WdfRequestRetrieveInputBuffer to obtain the input buffer for a write request or a device I/O control request, but not for a read request (because read requests do not provide input data).
The WdfRequestRetrieveInputBuffer method retrieves the input buffer for I/O requests that use the buffered I/O method or the direct I/O method for accessing data buffers. If the request's I/O control code is IRP_MJ_INTERNAL_DEVICE_CONTROL, or if the request came from another kernel-mode driver, WdfRequestRetrieveInputBuffer also supports I/O requests that use neither buffered nor direct I/O.
If WdfRequestRetrieveInputBuffer returns STATUS_SUCCESS, the driver receives the address and, optionally, the size of the input buffer.
The driver can access the retrieved buffer until it completes the I/O request that the Request parameter represents.
Instead of calling WdfRequestRetrieveInputBuffer, the driver can call WdfRequestRetrieveInputMemory, which creates a framework memory object that represents the buffer.
For more information about WdfRequestRetrieveInputBuffer, see Accessing Data Buffers in Framework-Based Drivers.
The following code example is part of the Serial sample driver's EvtIoDeviceControl callback function. If the I/O control code is IOCTL_SERIAL_SET_TIMEOUT, the driver obtains new time-out values from the I/O request's input buffer.
VOID
SerialEvtIoDeviceControl(
IN WDFQUEUE Queue,
IN WDFREQUEST Request,
IN size_t OutputBufferLength,
IN size_t InputBufferLength,
IN ULONG IoControlCode
)
{
PVOID buffer;
size_t bufSize;
switch (IoControlCode) {
...
case IOCTL_SERIAL_SET_TIMEOUTS: {
PSERIAL_TIMEOUTS NewTimeouts;
Status = WdfRequestRetrieveInputBuffer(
Request,
sizeof(SERIAL_TIMEOUTS),
&buffer,
&bufSize
);
if (!NT_SUCCESS(Status)) {
break;
}
NewTimeouts =(PSERIAL_TIMEOUTS)buffer;
}
...
}
WdfRequestRetrieveOutputBuffer
WdfUsbTargetDeviceRetrieveConfigDescriptor