/*++

Copyright (c) 1989  Microsoft Corporation

Module Name:

    lpclistn.c

Abstract:

    Local Inter-Process Communication (LPC) connection system services.

Author:

    Steve Wood (stevewo) 15-May-1989

Revision History:

--*/

#include "lpcp.h"

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


NTSTATUS
NtListenPort (
    IN HANDLE PortHandle,
    OUT PPORT_MESSAGE ConnectionRequest
    )

/*++

Routine Description:

    A server thread can listen for connection requests from client threads
    using the NtReplyWaitReceivePort service and looking for an
    LPC_CONNECTION_REQUEST message type.

    This call will loop, calling the NtReplyWaitReceivePort service, and
    return when it sees a message of type LPC_CONNECTION_REQUEST

Arguments:

    PortHandle - Specifies the connection port to listen for connection
        requests to.

    ConnectionRequest - Pointer to a structure that describes the
        connection request the client is making:

Return Value:

    NTSTATUS - An appropriate status value

--*/

{
    NTSTATUS Status;

    PAGED_CODE();

    //
    //  Keep on looping until we get a connection request on the lpc port
    //

    while (TRUE) {

        Status = NtReplyWaitReceivePort( PortHandle,
                                         NULL,
                                         NULL,
                                         ConnectionRequest );

        //
        //  We'll return from this procedure if ever we get back non success
        //  or the message is a connection request.  We still need to protect
        //  the testing of ConnectionRequest because it is a user supplied
        //  buffer.
        //

        try {

            if ((Status != STATUS_SUCCESS) ||
                ((ConnectionRequest->u2.s2.Type & ~LPC_KERNELMODE_MESSAGE) == LPC_CONNECTION_REQUEST)) {

                break;
            }

        } except( EXCEPTION_EXECUTE_HANDLER ) {

            Status = GetExceptionCode();

            break;
        }
    }

    //
    //  And return to our caller
    //

    return Status;
}