windows-nt-4.0/private/rpc/locator/newservr/server/mailslot.cxx

/*++

Microsoft Windows NT RPC Name Service
Copyright (c) 1995 Microsoft Corporation

Module Name:

    mailslot.cxx

Abstract:

	This file contains the implementations for non inline member functions
	of WRITE_MAIL_SLOT and READ_MAIL_SLOT, which are classes used for
	wrapping NT mailslot functionality.

Author:

    Satish Thatte (SatishT) 10/1/95  Created all the code below except where
									  otherwise indicated.

--*/

#define NULL 0

#include <globals.hxx>
#include <mailslot.hxx>
#include <objects.hxx>


WRITE_MAIL_SLOT::WRITE_MAIL_SLOT(
    IN STRING_T Target,
    IN STRING_T MailSlot
    )
/*++

Routine Description:

    open an existing NT MailSlot for writing.

Arguments:

    MailSlot - name of the WRITE_MAIL_SLOT

    Target - the workstation/domain to write to
--*/
{
	STRING_T SlotName;

	hWriteHandle = NULL;

	// STRING_T TargetPart;

	if (!Target) 	// this should only happen for broadcasts
		SlotName = catenate(TEXT("\\\\*"),MailSlot);

	else SlotName = catenate(Target,MailSlot);

	hWriteHandle = CreateFile(
						SlotName,
						GENERIC_WRITE, // | SYNCHRONIZE,  don't know if this is needed
						FILE_SHARE_WRITE,
						NULL,				// BUGBUG: punting on security
						OPEN_EXISTING,
						FILE_ATTRIBUTE_NORMAL,
						NULL
						);

	if (INVALID_HANDLE_VALUE == hWriteHandle) {
		hWriteHandle = NULL;
		delete [] SlotName;
		Raise(NSI_S_MAILSLOT_ERROR);
	}

	else delete [] SlotName;

}


WRITE_MAIL_SLOT::~WRITE_MAIL_SLOT(
    )
/*++

Routine Description:

    Deallocate a WRITE_MAIL_SLOT.

--*/
{
	if (hWriteHandle) CloseHandle(hWriteHandle);
}


DWORD
WRITE_MAIL_SLOT::Write(
    IN char * lpBuffer,
    IN DWORD nNumberOfBytesToWrite
    )
/*++

Routine Description:

    Write data to a mailslot.   
	
	The following may not be true at the moment:

	The mailslot is created with sync attributes,
    so there is no need to wait for the operation.

Arguments:

    lpBuffer - buffer to write.

    nNumberOfBytesToWrite - size of buffer to write.

Returns:

    Number of bytes written if write went OK. FALSE, otherwise.

--*/
{

	DWORD NumberOfBytesWritten;

	BOOL result = WriteFile(
					hWriteHandle,			// handle of file to write to 
					(LPCVOID) lpBuffer,		// address of data to write to file 
					nNumberOfBytesToWrite,	// number of bytes to write 
					&NumberOfBytesWritten,	// address of number of bytes written 
					NULL
					);

	if (result) return NumberOfBytesWritten;
	else return FALSE;
}



READ_MAIL_SLOT::READ_MAIL_SLOT(
    IN STRING_T MailSlot,
    IN DWORD nMaxMessageSize
    )
/*++

Routine Description:

    Create an NT mailslot.

Arguments:

    MailSlot - name of the READ_MAIL_SLOT

    nMaxMessageSize - the size of buffer to allocate for reads.

--*/
{
    STRING_T SlotName;

    Size = nMaxMessageSize;   // max buffer size for reads
    hReadHandle = NULL;

    // Form the name of the READ_MAIL_SLOT.

    SlotName = catenate(TEXT("\\\\."), MailSlot);

	hReadHandle = 
		CreateMailslot(
				SlotName,
				nMaxMessageSize,	// maximum message size
				NET_REPLY_INITIAL_TIMEOUT,	// milliseconds before read time-out
				NULL 	// address of security structure
				);

	if (INVALID_HANDLE_VALUE == hReadHandle) {
		hReadHandle = NULL;
		delete [] SlotName;
		Raise(NSI_S_MAILSLOT_ERROR);
	}

	else delete [] SlotName;
}


READ_MAIL_SLOT::~READ_MAIL_SLOT(
    )
/*++

Routine Description:

    Deallocate a READ_MAIL_SLOT.

--*/
{
	if (hReadHandle) CloseHandle(hReadHandle);
}



DWORD
READ_MAIL_SLOT::Read(
    IN OUT char * lpBuffer,	// info is filled in hence also OUT
	IN DWORD dwBufferSize,
    IN DWORD dwReadTimeout
    )
/*++

Routine Description:

    Read data from a mailslot.  The mailslot is created with async
    atrributes so that the read can be timed out.

Arguments:

    lpBuffer - buffer to read data into

    dwBufferSize - the size of the buffer

    dwReadTimeout - time to wait for a response.

Returns:

    Number of bytes actually read.

--*/
{
    SerializeReaders.Enter();

	BOOL success = SetMailslotInfo(
							hReadHandle,
							dwReadTimeout
							);	

	if (!success) {
		SerializeReaders.Leave();
		return FALSE;
	}

	DWORD NumberOfBytesRead;

	BOOL result = ReadFile(
					hReadHandle,	// handle of file to write to 
					lpBuffer,		// address of data buffer for reading
					dwBufferSize,	// number of bytes to read 
					&NumberOfBytesRead,	// address of number of bytes read 
					NULL			// no overlapping
					);


    SerializeReaders.Leave();

	if (result) return NumberOfBytesRead;
	else return FALSE;

}