fxwmiinstance.cpp File Reference

#include "fxwmipch.hpp"

Include dependency graph for fxwmiinstance.cpp:

Go to the source code of this file.

Functions
_Must_inspect_result_ __drv_sameIRQL	__drv_maxIRQL (PASSIVE_LEVEL) NTSTATUS FxWmiInstanceExternal

Function Documentation

__drv_maxIRQL()

_Must_inspect_result_ __drv_sameIRQL __drv_maxIRQL

(

PASSIVE_LEVEL

)

Definition at line 362 of file fxwmiinstance.cpp.

{
    NTSTATUS status;

    if (m_UseContextForQuery) {
        //
        // No matter what, we are reporting the length of the context.  If the
        // buffer is too small, it is used to report the desired buffer length.
        // Otherwise, it is the amount of data we copied to the query buffer.
        //
        *BufferUsed = m_ContextLength;

        if (OutBufferSize < m_ContextLength) {
            status = STATUS_BUFFER_TOO_SMALL;

            DoTraceLevelMessage(
                GetDriverGlobals(), TRACE_LEVEL_ERROR, TRACINGDEVICE,
                "WDFWMIINSTANCE %p query instance using context for query, "
                "query buffer length %d, context length %d, %!STATUS!",
                GetHandle(), OutBufferSize, m_ContextLength, status);
        }
        else {
            status = STATUS_SUCCESS;

            RtlCopyMemory(OutBuffer,
                          &GetContextHeader()->Context[0],
                          m_ContextLength);
        }
    }
    else if (m_QueryInstanceCallback.m_Method != NULL) {
        BYTE dummy;

        if (OutBufferSize == 0) {
            ASSERT(m_Provider->GetMinInstanceBufferSize() == 0);
            OutBuffer = (PVOID) &dummy;
            OutBufferSize = sizeof(dummy);
        }

        status = m_QueryInstanceCallback.Invoke(
            GetDevice()->GetHandle(),
            GetHandle(),
            OutBufferSize,
            OutBuffer,
            BufferUsed
            );

        if (status == STATUS_PENDING) {
            DoTraceLevelMessage(
                GetDriverGlobals(), TRACE_LEVEL_ERROR, TRACINGPNP,
                "WDFWMIINSTANCE %p was queried and returned %!STATUS!, which is "
                "not an allowed return value", GetHandle(), status);

            FxVerifierDbgBreakPoint(GetDriverGlobals());

            status = STATUS_UNSUCCESSFUL;
            *BufferUsed = 0;
        }
        else if (NT_SUCCESS(status)) {
            if (*BufferUsed > OutBufferSize) {
                //
                // Caller error, they returned more bytes in *BufferUsed then
                // was passed in via OutBufferSize, yet returned NT_SUCCESS
                //
                DoTraceLevelMessage(
                    GetDriverGlobals(), TRACE_LEVEL_ERROR, TRACINGPNP,
                    "WDFWMIINSTANCE %p was queried with buffer size %d, "
                    " but returned %d bytes and %!STATUS!, should return "
                    "!NT_SUCCESS in this case",
                    GetHandle(), OutBufferSize, *BufferUsed, status);

                FxVerifierDbgBreakPoint(GetDriverGlobals());

                status = STATUS_UNSUCCESSFUL;
                *BufferUsed = 0;
            }
            else if (OutBuffer == &dummy && *BufferUsed > 0) {
                //
                // Convert success back to an error where we can report the
                // required size back to the caller.
                //
                status = STATUS_BUFFER_TOO_SMALL;
            }
        }
        else if (status == STATUS_BUFFER_TOO_SMALL) {
            if (m_Provider->GetMinInstanceBufferSize()) {
                DoTraceLevelMessage(
                    GetDriverGlobals(), TRACE_LEVEL_ERROR, TRACINGPNP,
                    "WDFWMIINSTANCE %p returned %!STATUS!, but it specified "
                    "a minimum instance size %d in its WDFWMIPROVIDER %p",
                    GetHandle(), status, m_Provider->GetMinInstanceBufferSize(),
                    m_Provider->GetHandle());
                DoTraceLevelMessage(
                    GetDriverGlobals(), TRACE_LEVEL_ERROR, TRACINGPNP,
                    "This is a break in the contract.  Minimum instance size "
                    "should only be used for fixed sized instances");

                FxVerifierDbgBreakPoint(GetDriverGlobals());
            }
        }
    }
    else {
        ASSERT(m_ExecuteMethodCallback.m_Method != NULL);

        DoTraceLevelMessage(
            GetDriverGlobals(), TRACE_LEVEL_ERROR, TRACINGPNP,
            "WDFWMIINSTANCE %p was queried with no query callback and supports "
            "execute method (%p), zero bytes returned", GetHandle(),
            m_ExecuteMethodCallback.m_Method);

        status = STATUS_SUCCESS;
        *BufferUsed = 0;
    }

    return status;
}