fxchildlistapi.cpp

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/*++
 
Copyright (c) Microsoft Corporation.  All rights reserved.
 
Module Name:
 
    FxChildListApi.cpp
 
Abstract:
 
    This module exposes the "C" interface to the FxChildList object.
 
Author:
 
 
 
Environment:
 
    Kernel mode only
 
Revision History:
 
--*/
 
#include "fxcorepch.hpp"
 
extern "C" {
// #include "FxChildListAPI.tmh"
}
 
//
// extern "C" the entire file
//
extern "C" {
 
_Must_inspect_result_
__drv_maxIRQL(PASSIVE_LEVEL)
NTSTATUS
STDCALL
WDFEXPORT(WdfChildListCreate)(
    __in
    PWDF_DRIVER_GLOBALS DriverGlobals,
    __in
    WDFDEVICE Device,
    __in
    PWDF_CHILD_LIST_CONFIG Config,
    __in_opt
    PWDF_OBJECT_ATTRIBUTES DeviceListAttributes,
    __out
    WDFCHILDLIST* DeviceList
    )
{
    PFX_DRIVER_GLOBALS pFxDriverGlobals;
    FxDevice* pDevice;
    FxChildList* pList;
    size_t totalDescriptionSize = 0;
    NTSTATUS status;
 
    FxObjectHandleGetPtrAndGlobals(GetFxDriverGlobals(DriverGlobals),
                                   Device,
                                   FX_TYPE_DEVICE,
                                   (PVOID*)&pDevice,
                                   &pFxDriverGlobals);
 
    DoTraceLevelMessage(pFxDriverGlobals, TRACE_LEVEL_VERBOSE, TRACINGPNP,
                        "Enter, WDFDEVICE %p", Device);
 
    FxPointerNotNull(pFxDriverGlobals, Config);
    FxPointerNotNull(pFxDriverGlobals, DeviceList);
 
    *DeviceList = NULL;
 
    status = FxVerifierCheckIrqlLevel(pFxDriverGlobals, PASSIVE_LEVEL);
    if (!NT_SUCCESS(status)) {
        return status;
    }
 
    status = FxChildList::_ValidateConfig(pFxDriverGlobals,
                                          Config,
                                          &totalDescriptionSize);
    if (!NT_SUCCESS(status)) {
         DoTraceLevelMessage(pFxDriverGlobals, TRACE_LEVEL_ERROR, TRACINGPNP,
                            "WDFDEVICE 0x%p Config is invalid", Device);
        return status;
    }
 
    status = FxValidateObjectAttributes(pFxDriverGlobals,
                                        DeviceListAttributes,
                                        FX_VALIDATE_OPTION_PARENT_NOT_ALLOWED);
    if (!NT_SUCCESS(status)) {
        return status;
    }
 
    status = pDevice->AllocateEnumInfo();
    if (!NT_SUCCESS(status)) {
        return status;
    }
 
    status = FxChildList::_CreateAndInit(&pList,
                                         pFxDriverGlobals,
                                         DeviceListAttributes,
                                         totalDescriptionSize,
                                         pDevice,
                                         Config);
    if (!NT_SUCCESS(status)) {
        return status;
    }
 
    status = pList->Commit(DeviceListAttributes,
                           (WDFOBJECT*)DeviceList,
                           pDevice);
 
    if (!NT_SUCCESS(status)) {
        DoTraceLevelMessage(pFxDriverGlobals, TRACE_LEVEL_ERROR, TRACINGPNP,
                            "Could not convert object to handle, %!STATUS!",
                            status);
        pList->DeleteFromFailedCreate();
    }
 
    if (NT_SUCCESS(status)) {
        pDevice->SetDeviceTelemetryInfoFlags(DeviceInfoHasDynamicChildren);
    }
 
    return status;
}
 
__drv_maxIRQL(DISPATCH_LEVEL)
WDFDEVICE
STDCALL
WDFEXPORT(WdfChildListGetDevice)(
    __in
    PWDF_DRIVER_GLOBALS DriverGlobals,
    __in
    WDFCHILDLIST DeviceList
    )
{
    PFX_DRIVER_GLOBALS pFxDriverGlobals;
    FxChildList* pList;
 
    FxObjectHandleGetPtrAndGlobals(GetFxDriverGlobals(DriverGlobals),
                                   DeviceList,
                                   FX_TYPE_CHILD_LIST,
                                   (PVOID*)&pList,
                                   &pFxDriverGlobals);
 
    DoTraceLevelMessage(pFxDriverGlobals, TRACE_LEVEL_VERBOSE, TRACINGPNP,
                        "Enter: WDFCHILDLIST %p", DeviceList);
 
    return pList->GetDevice();
}
 
_Must_inspect_result_
__drv_maxIRQL(DISPATCH_LEVEL)
NTSTATUS
STDCALL
WDFEXPORT(WdfChildListRetrieveAddressDescription)(
    __in
    PWDF_DRIVER_GLOBALS DriverGlobals,
    __in
    WDFCHILDLIST DeviceList,
    __in
    PWDF_CHILD_IDENTIFICATION_DESCRIPTION_HEADER IdentificationDescription,
    __inout
    PWDF_CHILD_ADDRESS_DESCRIPTION_HEADER AddressDescription
    )
{
    PFX_DRIVER_GLOBALS pFxDriverGlobals;
    FxChildList* pList;
    NTSTATUS status;
 
    FxObjectHandleGetPtrAndGlobals(GetFxDriverGlobals(DriverGlobals),
                                   DeviceList,
                                   FX_TYPE_CHILD_LIST,
                                   (PVOID*)&pList,
                                   &pFxDriverGlobals);
 
    DoTraceLevelMessage(pFxDriverGlobals, TRACE_LEVEL_VERBOSE, TRACINGPNP,
                        "Enter: WDFCHILDLIST %p", DeviceList);
 
    FxPointerNotNull(pFxDriverGlobals, IdentificationDescription);
    FxPointerNotNull(pFxDriverGlobals, AddressDescription);
 
    if (pList->GetIdentificationDescriptionSize() !=
                    IdentificationDescription->IdentificationDescriptionSize) {
        status = STATUS_INVALID_DEVICE_REQUEST;
 
        DoTraceLevelMessage(
            pFxDriverGlobals, TRACE_LEVEL_ERROR, TRACINGPNP,
            "identification description size %d incorrect, expected %d, %!STATUS!",
            IdentificationDescription->IdentificationDescriptionSize,
            pList->GetIdentificationDescriptionSize(), status);
 
        return status;
    }
 
    if (pList->HasAddressDescriptions() == FALSE) {
        status = STATUS_INVALID_DEVICE_REQUEST;
 
        DoTraceLevelMessage(pFxDriverGlobals, TRACE_LEVEL_ERROR, TRACINGPNP,
                            "cannot retrieve an address description from a list"
                            " which was not initialized to use them, %!STATUS!",
                            status);
 
        return status;
    }
 
    if (pList->GetAddressDescriptionSize() !=
                                AddressDescription->AddressDescriptionSize) {
        status = STATUS_INVALID_DEVICE_REQUEST;
 
        DoTraceLevelMessage(pFxDriverGlobals, TRACE_LEVEL_ERROR, TRACINGPNP,
                            "description size %d incorrect, expected %d, %!STATUS!",
                            AddressDescription->AddressDescriptionSize,
                            pList->GetAddressDescriptionSize(), status);
 
        return status;
    }
 
    status = pList->GetAddressDescription(IdentificationDescription,
                                          AddressDescription);
 
    DoTraceLevelMessage(pFxDriverGlobals, TRACE_LEVEL_VERBOSE, TRACINGPNP,
                        "Exit: WDFCHILDLIST %p, %!STATUS!",
                        DeviceList, status);
 
    return status;
 
}
 
__drv_maxIRQL(DISPATCH_LEVEL)
VOID
STDCALL
WDFEXPORT(WdfChildListBeginScan)(
    __in
    PWDF_DRIVER_GLOBALS DriverGlobals,
    __in
    WDFCHILDLIST DeviceList
    )
{
    PFX_DRIVER_GLOBALS pFxDriverGlobals;
    FxChildList* pList;
 
    FxObjectHandleGetPtrAndGlobals(GetFxDriverGlobals(DriverGlobals),
                                   DeviceList,
                                   FX_TYPE_CHILD_LIST,
                                   (PVOID*)&pList,
                                   &pFxDriverGlobals);
 
    DoTraceLevelMessage(pFxDriverGlobals, TRACE_LEVEL_VERBOSE, TRACINGPNP,
                        "Enter: WDFCHILDLIST %p", DeviceList);
 
    pList->BeginScan();
}
 
__drv_maxIRQL(DISPATCH_LEVEL)
VOID
STDCALL
WDFEXPORT(WdfChildListEndScan)(
    __in
    PWDF_DRIVER_GLOBALS DriverGlobals,
    __in
    WDFCHILDLIST DeviceList
    )
{
    PFX_DRIVER_GLOBALS pFxDriverGlobals;
    FxChildList* pList;
 
    FxObjectHandleGetPtrAndGlobals(GetFxDriverGlobals(DriverGlobals),
                                   DeviceList,
                                   FX_TYPE_CHILD_LIST,
                                   (PVOID*)&pList,
                                   &pFxDriverGlobals);
 
    DoTraceLevelMessage(pFxDriverGlobals, TRACE_LEVEL_VERBOSE, TRACINGPNP,
                        "Enter: WDFCHILDLIST %p", DeviceList);
 
    pList->EndScan();
}
 
__drv_maxIRQL(DISPATCH_LEVEL)
VOID
STDCALL
WDFEXPORT(WdfChildListBeginIteration)(
    __in
    PWDF_DRIVER_GLOBALS DriverGlobals,
    __in
    WDFCHILDLIST DeviceList,
    __in
    PWDF_CHILD_LIST_ITERATOR Iterator
    )
{
    PFX_DRIVER_GLOBALS pFxDriverGlobals;
    FxChildList* pList;
 
    FxObjectHandleGetPtrAndGlobals(GetFxDriverGlobals(DriverGlobals),
                                   DeviceList,
                                   FX_TYPE_CHILD_LIST,
                                   (PVOID*)&pList,
                                   &pFxDriverGlobals);
 
    DoTraceLevelMessage(pFxDriverGlobals, TRACE_LEVEL_VERBOSE, TRACINGPNP,
                        "Enter: WDFCHILDLIST %p", DeviceList);
 
    FxPointerNotNull(pFxDriverGlobals, Iterator);
 
    if (Iterator->Size != sizeof(WDF_CHILD_LIST_ITERATOR)) {
        DoTraceLevelMessage(pFxDriverGlobals, TRACE_LEVEL_ERROR, TRACINGPNP,
                            "Iterator Size %d not correct, expected %d, %!STATUS!",
                            Iterator->Size, sizeof(WDF_CHILD_LIST_ITERATOR),
                            STATUS_INFO_LENGTH_MISMATCH);
        FxVerifierDbgBreakPoint(pFxDriverGlobals);
        return;
    }
 
    if ((Iterator->Flags & ~WdfRetrieveAllChildren) != 0) {
        DoTraceLevelMessage(
            pFxDriverGlobals, TRACE_LEVEL_ERROR, TRACINGPNP,
            "Iterator Flags 0x%x not correct, valid mask 0x%x, %!STATUS!",
            Iterator->Flags, WdfRetrieveAllChildren, STATUS_INVALID_PARAMETER);
        FxVerifierDbgBreakPoint(pFxDriverGlobals);
        return;
    }
 
    RtlZeroMemory(&Iterator->Reserved[0], sizeof(Iterator->Reserved));
 
    pList->BeginIteration(Iterator);
}
 
_Must_inspect_result_
__drv_maxIRQL(DISPATCH_LEVEL)
NTSTATUS
STDCALL
WDFEXPORT(WdfChildListRetrieveNextDevice)(
    __in
    PWDF_DRIVER_GLOBALS DriverGlobals,
    __in
    WDFCHILDLIST DeviceList,
    __in
    PWDF_CHILD_LIST_ITERATOR Iterator,
    __out
    WDFDEVICE* Device,
    __inout_opt
    PWDF_CHILD_RETRIEVE_INFO Info
    )
{
    PFX_DRIVER_GLOBALS pFxDriverGlobals;
    FxChildList* pList;
    NTSTATUS status;
 
    FxObjectHandleGetPtrAndGlobals(GetFxDriverGlobals(DriverGlobals),
                                   DeviceList,
                                   FX_TYPE_CHILD_LIST,
                                   (PVOID*)&pList,
                                   &pFxDriverGlobals);
 
    FxPointerNotNull(pFxDriverGlobals, Iterator);
    FxPointerNotNull(pFxDriverGlobals, Device);
 
    *Device = NULL;
 
    if (Iterator->Size != sizeof(WDF_CHILD_LIST_ITERATOR)) {
        status = STATUS_INFO_LENGTH_MISMATCH;
        DoTraceLevelMessage(pFxDriverGlobals, TRACE_LEVEL_ERROR, TRACINGPNP,
                            "Iterator Size %d not correct, expected %d, %!STATUS!",
                            Iterator->Size, sizeof(WDF_CHILD_LIST_ITERATOR), status);
        return status;
    }
 
    if ((Iterator->Flags & ~WdfRetrieveAllChildren) != 0) {
        status = STATUS_INVALID_PARAMETER;
        DoTraceLevelMessage(
            pFxDriverGlobals, TRACE_LEVEL_ERROR, TRACINGPNP,
            "Iterator Flags 0x%x not correct, valid mask 0x%x, %!STATUS!",
            Iterator->Flags, WdfRetrieveAllChildren, status);
        return status;
    }
 
    if (Info != NULL) {
        if (Info->Size != sizeof(WDF_CHILD_RETRIEVE_INFO)) {
            status = STATUS_INFO_LENGTH_MISMATCH;
            DoTraceLevelMessage(
                pFxDriverGlobals, TRACE_LEVEL_ERROR, TRACINGPNP,
                "Invalid RetrieveInfo Size %d, expected %d, %!STATUS!",
                Info->Size, sizeof(WDF_CHILD_RETRIEVE_INFO), status);
            return status;
        }
        if (Info->IdentificationDescription != NULL
            &&
            pList->GetIdentificationDescriptionSize() !=
                Info->IdentificationDescription->IdentificationDescriptionSize) {
            status = STATUS_INVALID_PARAMETER;
 
            DoTraceLevelMessage(
                pFxDriverGlobals, TRACE_LEVEL_ERROR, TRACINGPNP,
                "identification description size %d incorrect, expected %d"
                "%!STATUS!",
                Info->IdentificationDescription->IdentificationDescriptionSize,
                pList->GetIdentificationDescriptionSize(), status);
 
            return status;
        }
 
        if (Info->AddressDescription != NULL) {
            if (pList->HasAddressDescriptions() == FALSE) {
                status = STATUS_INVALID_DEVICE_REQUEST;
 
                DoTraceLevelMessage(
                    pFxDriverGlobals, TRACE_LEVEL_ERROR, TRACINGPNP,
                    "cannot retrieve an address description from a list"
                    " which was not initialized to use them, %!STATUS!",
                    status);
 
                return status;
            }
            else if (pList->GetAddressDescriptionSize() !=
                            Info->AddressDescription->AddressDescriptionSize) {
                status = STATUS_INVALID_PARAMETER;
 
                DoTraceLevelMessage(
                    pFxDriverGlobals, TRACE_LEVEL_ERROR, TRACINGPNP,
                    "address description size %d incorrect, expected %d, %!STATUS!",
                    Info->AddressDescription->AddressDescriptionSize,
                    pList->GetAddressDescriptionSize(), status);
 
                return status;
            }
        }
    }
 
    return pList->GetNextDevice(Device, Iterator, Info);
}
 
__drv_maxIRQL(DISPATCH_LEVEL)
VOID
STDCALL
WDFEXPORT(WdfChildListEndIteration)(
    __in
    PWDF_DRIVER_GLOBALS DriverGlobals,
    __in
    WDFCHILDLIST DeviceList,
    __in
    PWDF_CHILD_LIST_ITERATOR Iterator
    )
{
    FxChildList* pList;
    PFX_DRIVER_GLOBALS pFxDriverGlobals;
 
    FxObjectHandleGetPtrAndGlobals(GetFxDriverGlobals(DriverGlobals),
                                   DeviceList,
                                   FX_TYPE_CHILD_LIST,
                                   (PVOID*)&pList,
                                   &pFxDriverGlobals);
 
    DoTraceLevelMessage(pFxDriverGlobals, TRACE_LEVEL_VERBOSE, TRACINGPNP,
                        "Enter: WDFCHILDLIST %p", DeviceList);
 
    FxPointerNotNull(pFxDriverGlobals, Iterator);
 
    if (Iterator->Size != sizeof(WDF_CHILD_LIST_ITERATOR)) {
        DoTraceLevelMessage(pFxDriverGlobals, TRACE_LEVEL_ERROR, TRACINGPNP,
                            "Iterator Size %d not correct, expected %d, %!STATUS!",
                            Iterator->Size, sizeof(WDF_CHILD_LIST_ITERATOR),
                            STATUS_INFO_LENGTH_MISMATCH);
        FxVerifierDbgBreakPoint(pFxDriverGlobals);
        return;
    }
 
    if ((Iterator->Flags & ~WdfRetrieveAllChildren) != 0) {
        DoTraceLevelMessage(
            pFxDriverGlobals, TRACE_LEVEL_ERROR, TRACINGPNP,
            "Iterator Flags 0x%x not correct, valid mask 0x%x, %!STATUS!",
            Iterator->Flags, WdfRetrieveAllChildren, STATUS_INVALID_PARAMETER);
        FxVerifierDbgBreakPoint(pFxDriverGlobals);
        return;
    }
 
    pList->EndIteration(Iterator);
}
 
 
_Must_inspect_result_
__drv_maxIRQL(DISPATCH_LEVEL)
NTSTATUS
STDCALL
WDFEXPORT(WdfChildListAddOrUpdateChildDescriptionAsPresent)(
    __in
    PWDF_DRIVER_GLOBALS DriverGlobals,
    __in
    WDFCHILDLIST DeviceList,
    __in
    PWDF_CHILD_IDENTIFICATION_DESCRIPTION_HEADER IdentificationDescription,
    __in_opt
    PWDF_CHILD_ADDRESS_DESCRIPTION_HEADER AddressDescription
    )
{
    PFX_DRIVER_GLOBALS pFxDriverGlobals;
    FxChildList* pList;
    NTSTATUS status;
 
    FxObjectHandleGetPtrAndGlobals(GetFxDriverGlobals(DriverGlobals),
                                   DeviceList,
                                   FX_TYPE_CHILD_LIST,
                                   (PVOID*)&pList,
                                   &pFxDriverGlobals);
 
    DoTraceLevelMessage(pFxDriverGlobals, TRACE_LEVEL_VERBOSE, TRACINGPNP,
                        "Enter: WDFCHILDLIST %p", DeviceList);
 
    FxPointerNotNull(pFxDriverGlobals, IdentificationDescription);
 
    if (AddressDescription != NULL) {
        if (pList->HasAddressDescriptions() == FALSE) {
            status =  STATUS_INVALID_DEVICE_REQUEST;
 
            DoTraceLevelMessage(
                pFxDriverGlobals, TRACE_LEVEL_ERROR, TRACINGPNP,
                "cannot retrieve an address description from a list"
                " which was not initialized to use them, %!STATUS!", status);
 
            return status;
        }
        if (pList->GetAddressDescriptionSize() !=
                                AddressDescription->AddressDescriptionSize) {
            status = STATUS_INVALID_DEVICE_REQUEST;
 
            DoTraceLevelMessage(
                pFxDriverGlobals, TRACE_LEVEL_ERROR, TRACINGPNP,
                "address description size %d incorrect, expected %d, %!STATUS!",
                AddressDescription->AddressDescriptionSize,
                pList->GetAddressDescriptionSize(), status);
 
            return status;
        }
    }
    else {
        if (pList->HasAddressDescriptions()) {
            status =  STATUS_INVALID_DEVICE_REQUEST;
 
            DoTraceLevelMessage(
                pFxDriverGlobals, TRACE_LEVEL_ERROR, TRACINGPNP,
                "Must provide a valid AddressDescription because the"
                " WDFCHILDLIST 0x%p is configured with AddressDescriptionSize,"
                " %!STATUS!", DeviceList, status);
 
            return status;
        }
    }
 
    if (pList->GetIdentificationDescriptionSize() !=
                    IdentificationDescription->IdentificationDescriptionSize) {
        status = STATUS_INVALID_DEVICE_REQUEST;
 
        DoTraceLevelMessage(
            pFxDriverGlobals, TRACE_LEVEL_ERROR, TRACINGPNP,
            "identification description size %d incorrect, expected %d, %!STATUS!",
            IdentificationDescription->IdentificationDescriptionSize,
            pList->GetIdentificationDescriptionSize(), status);
 
        return status;
    }
 
    status = pList->Add(IdentificationDescription, AddressDescription);
 
    DoTraceLevelMessage(pFxDriverGlobals, TRACE_LEVEL_VERBOSE, TRACINGPNP,
                        "Exit: WDFCHILDLIST %p, %!STATUS!", DeviceList, status);
 
    return status;
}
 
_Must_inspect_result_
__drv_maxIRQL(DISPATCH_LEVEL)
NTSTATUS
STDCALL
WDFEXPORT(WdfChildListUpdateChildDescriptionAsMissing)(
    __in
    PWDF_DRIVER_GLOBALS DriverGlobals,
    __in
    WDFCHILDLIST DeviceList,
    __in
    PWDF_CHILD_IDENTIFICATION_DESCRIPTION_HEADER IdentificationDescription
    )
{
    PFX_DRIVER_GLOBALS pFxDriverGlobals;
    NTSTATUS status;
    FxChildList* pList;
 
    FxObjectHandleGetPtrAndGlobals(GetFxDriverGlobals(DriverGlobals),
                                   DeviceList,
                                   FX_TYPE_CHILD_LIST,
                                   (PVOID*)&pList,
                                   &pFxDriverGlobals);
 
    FxPointerNotNull(pFxDriverGlobals, IdentificationDescription);
 
    DoTraceLevelMessage(pFxDriverGlobals, TRACE_LEVEL_VERBOSE, TRACINGPNP,
                        "Enter: WDFCHILDLIST %p", DeviceList);
 
    if (pList->GetIdentificationDescriptionSize() !=
                    IdentificationDescription->IdentificationDescriptionSize) {
        status = STATUS_INVALID_DEVICE_REQUEST;
 
        DoTraceLevelMessage(
            pFxDriverGlobals, TRACE_LEVEL_ERROR, TRACINGPNP,
            "identification description size %d incorrect, expected %d, %!STATUS!",
            IdentificationDescription->IdentificationDescriptionSize,
            pList->GetIdentificationDescriptionSize(), status);
 
        return status;
    }
 
    status = pList->UpdateAsMissing(IdentificationDescription);
 
    DoTraceLevelMessage(pFxDriverGlobals, TRACE_LEVEL_VERBOSE, TRACINGPNP,
                        "Exit: WDFCHILDLIST %p, %!STATUS!",
                        DeviceList, status);
 
    return status;
}
 
__drv_maxIRQL(DISPATCH_LEVEL)
VOID
STDCALL
WDFEXPORT(WdfChildListUpdateAllChildDescriptionsAsPresent)(
    __in
    PWDF_DRIVER_GLOBALS DriverGlobals,
    __in
    WDFCHILDLIST DeviceList
    )
{
    PFX_DRIVER_GLOBALS pFxDriverGlobals;
    FxChildList* pList;
 
    FxObjectHandleGetPtrAndGlobals(GetFxDriverGlobals(DriverGlobals),
                                   DeviceList,
                                   FX_TYPE_CHILD_LIST,
                                   (PVOID*)&pList,
                                   &pFxDriverGlobals);
 
    DoTraceLevelMessage(pFxDriverGlobals, TRACE_LEVEL_VERBOSE, TRACINGPNP,
                        "Enter: WDFCHILDLIST %p", DeviceList);
 
    pList->UpdateAllAsPresent();
 
    DoTraceLevelMessage(pFxDriverGlobals, TRACE_LEVEL_VERBOSE, TRACINGPNP,
                        "Exit: WDFCHILDLIST %p", DeviceList);
}
 
_Must_inspect_result_
__drv_maxIRQL(DISPATCH_LEVEL)
WDFDEVICE
STDCALL
WDFEXPORT(WdfChildListRetrievePdo)(
    __in
    PWDF_DRIVER_GLOBALS DriverGlobals,
    __in
    WDFCHILDLIST DeviceList,
    __inout
    PWDF_CHILD_RETRIEVE_INFO RetrieveInfo
    )
{
    FxChildList* pList;
    PWDF_CHILD_IDENTIFICATION_DESCRIPTION_HEADER pId;
    PWDF_CHILD_ADDRESS_DESCRIPTION_HEADER pAddr;
    FxDevice* device;
    PFX_DRIVER_GLOBALS pFxDriverGlobals;
 
    FxObjectHandleGetPtrAndGlobals(GetFxDriverGlobals(DriverGlobals),
                                   DeviceList,
                                   FX_TYPE_CHILD_LIST,
                                   (PVOID*)&pList,
                                   &pFxDriverGlobals);
 
    DoTraceLevelMessage(pFxDriverGlobals, TRACE_LEVEL_VERBOSE, TRACINGPNP,
                        "Enter: WDFCHILDLIST %p", DeviceList);
 
    FxPointerNotNull(pFxDriverGlobals, RetrieveInfo);
 
    if (RetrieveInfo->Size != sizeof(WDF_CHILD_RETRIEVE_INFO)) {
        DoTraceLevelMessage(
            pFxDriverGlobals, TRACE_LEVEL_ERROR, TRACINGPNP,
            "Invalid RetrieveInfo Size %x, expected %d, %!STATUS!",
            RetrieveInfo->Size, sizeof(WDF_CHILD_RETRIEVE_INFO),
            STATUS_INFO_LENGTH_MISMATCH);
        return NULL;
    }
 
    pId = RetrieveInfo->IdentificationDescription;
    if (pId == NULL) {
        DoTraceLevelMessage(pFxDriverGlobals, TRACE_LEVEL_ERROR, TRACINGPNP,
                            "Invalid ID Description, %!STATUS!",
                            STATUS_INVALID_PARAMETER);
        return NULL;
    }
 
    if (pList->GetIdentificationDescriptionSize() !=
                                        pId->IdentificationDescriptionSize) {
        DoTraceLevelMessage(
            pFxDriverGlobals, TRACE_LEVEL_ERROR, TRACINGPNP,
            "identification description size %d incorrect, expected %d",
            pId->IdentificationDescriptionSize,
            pList->GetIdentificationDescriptionSize());
 
        return NULL;
    }
 
    pAddr = RetrieveInfo->AddressDescription;
    if (pAddr != NULL) {
        if (pList->HasAddressDescriptions() == FALSE) {
            DoTraceLevelMessage(
                pFxDriverGlobals, TRACE_LEVEL_ERROR, TRACINGPNP,
                "cannot retrieve an address description from a list"
                " which was not initialized to use them, %!STATUS!",
                STATUS_INVALID_DEVICE_REQUEST);
            return NULL;
        }
        else if (pList->GetAddressDescriptionSize() != pAddr->AddressDescriptionSize) {
            DoTraceLevelMessage(
                pFxDriverGlobals, TRACE_LEVEL_ERROR, TRACINGPNP,
                "address description size %d incorrect, expected %d",
                pAddr->AddressDescriptionSize, pList->GetAddressDescriptionSize());
 
            return NULL;
        }
    }
 
    RetrieveInfo->Status = WdfChildListRetrieveDeviceUndefined;
 
    device = pList->GetDeviceFromId(RetrieveInfo);
 
    WDFDEVICE handle;
 
    if (device != NULL) {
        handle = device->GetHandle();
    }
    else {
        handle = NULL;
    }
 
    DoTraceLevelMessage(pFxDriverGlobals, TRACE_LEVEL_VERBOSE, TRACINGPNP,
                        "Exit: WDFCHILDLIST %p, WDFDEVICE Pdo %p, "
                        "%!WDF_CHILD_LIST_RETRIEVE_DEVICE_STATUS!",
                        DeviceList, handle, RetrieveInfo->Status);
 
    return handle;
}
 
__drv_maxIRQL(DISPATCH_LEVEL)
BOOLEAN
STDCALL
WDFEXPORT(WdfChildListRequestChildEject)(
    __in
    PWDF_DRIVER_GLOBALS DriverGlobals,
    __in
    WDFCHILDLIST DeviceList,
    __in
    PWDF_CHILD_IDENTIFICATION_DESCRIPTION_HEADER IdentificationDescription
    )
{
    FxChildList* pList;
    FxDevice* device;
    PFX_DRIVER_GLOBALS pFxDriverGlobals;
 
    FxObjectHandleGetPtrAndGlobals(GetFxDriverGlobals(DriverGlobals),
                                   DeviceList,
                                   FX_TYPE_CHILD_LIST,
                                   (PVOID*)&pList,
                                   &pFxDriverGlobals);
 
    DoTraceLevelMessage(pFxDriverGlobals, TRACE_LEVEL_VERBOSE, TRACINGPNP,
                        "Enter: WDFCHILDLIST %p", DeviceList);
 
    FxPointerNotNull(pFxDriverGlobals, IdentificationDescription);
 
    if (pList->GetIdentificationDescriptionSize() !=
                    IdentificationDescription->IdentificationDescriptionSize) {
        DoTraceLevelMessage(
            pFxDriverGlobals, TRACE_LEVEL_ERROR, TRACINGPNP,
            "identification description size 0x%x incorrect, expected 0x%x",
            IdentificationDescription->IdentificationDescriptionSize,
            pList->GetIdentificationDescriptionSize());
 
        return FALSE;
    }
 
    WDF_CHILD_RETRIEVE_INFO info;
 
    WDF_CHILD_RETRIEVE_INFO_INIT(&info, IdentificationDescription);
 
    device = pList->GetDeviceFromId(&info);
 
    DoTraceLevelMessage(pFxDriverGlobals, TRACE_LEVEL_VERBOSE, TRACINGPNP,
                        "found: WDFCHILDLIST %p, WDFDEVICE PDO %p",
                        DeviceList, device == NULL ? NULL : device->GetHandle());
 
    if (device != NULL) {
        PDEVICE_OBJECT pdo;
 
        //
        // Make sure we have a valid PDO that can be ejected
        //
        pdo = device->GetSafePhysicalDevice();
 
        if (pdo != NULL) {
            IoRequestDeviceEject(pdo);
            return TRUE;
        }
        else {
            DoTraceLevelMessage(pFxDriverGlobals, TRACE_LEVEL_ERROR, TRACINGDEVICE,
                                "PDO WDFDEVICE %p not reported yet to pnp, cannot eject!",
                                device->GetHandle());
        }
    }
 
    return FALSE;
}
 
} // extern "C" of entire file