/*++
Copyright (c) 1989  Microsoft Corporation

Module Name:
    lpcquery.c

Abstract:
    Local Inter-Process Communication (LPC) query services

Author:
    Steve Wood (stevewo) 15-May-1989
--*/

#include "lpcp.h"

#ifdef ALLOC_PRAGMA
#pragma alloc_text(PAGE,NtQueryInformationPort)
#endif


NTSTATUS NTAPI NtQueryInformationPort(IN HANDLE PortHandle OPTIONAL,
                                      IN PORT_INFORMATION_CLASS PortInformationClass,
                                      OUT PVOID PortInformation,
                                      IN ULONG Length,
                                      OUT PULONG ReturnLength OPTIONAL)
/*++
Routine Description:
    This routine should be used to query an lpc port, but is pretty much a
    noop.  Currently it can only indicate if the input handle is for a port object.
Arguments:
    PortHandle - Supplies the handle for the port being queried
    PortInformationClass - Specifies the type information class being asked for.  Currently ignored.
    PortInformation - Supplies a pointer to the buffer to receive the information.  Currently just probed and then ignored.
    Length - Specifies, in bytes, the size of the port information buffer.
    ReturnLength  - Optionally receives the size, in bytes, of the information being returned.  Currently just probed and then ignored.
Return Value:
    NTSTATUS - An appropriate status value.
--*/
{
    KPROCESSOR_MODE PreviousMode;
    NTSTATUS Status;
    PLPCP_PORT_OBJECT PortObject;

    PAGED_CODE();

    //  Get previous processor mode and probe output argument if necessary.
    PreviousMode = KeGetPreviousMode();
    if (PreviousMode != KernelMode) {
        try {
            ProbeForWrite(PortInformation, Length, sizeof(ULONG));
            if (ARGUMENT_PRESENT(ReturnLength)) {
                ProbeForWriteUlong(ReturnLength);
            }
        } except(EXCEPTION_EXECUTE_HANDLER)
        {
            return(GetExceptionCode());
        }
    }

    //  If the user gave us a handle then reference the object.  And return
    //  success if we got a good reference and an error otherwise.
    if (ARGUMENT_PRESENT(PortHandle)) {
        Status = ObReferenceObjectByHandle(PortHandle, GENERIC_READ, LpcPortObjectType, PreviousMode, &PortObject, NULL);
        if (!NT_SUCCESS(Status)) {
            return(Status);
        }

        ObDereferenceObject(PortObject);
        return STATUS_SUCCESS;
    } else {
        return STATUS_INVALID_INFO_CLASS;
    }
}