connld(7)                                                  connld(7)


       NAME
             connld - line discipline for unique stream connections

       DESCRIPTION
             connld is a STREAMS-based module that provides unique
             connections between server and client processes.  It can only
             be pushed [see streamio(7)] onto one end of a STREAMS-based
             pipe that may subsequently be attached to a name in the file
             system name space.  After the pipe end is attached, a new pipe
             is created internally when an originating process attempts to
             open(2) or creat(2) the file system name.  A file descriptor
             for one end of the new pipe is packaged into a message
             identical to that for the ioctl I_SENDFD [see streamio(7)] and
             is transmitted along the stream to the server process on the
             other end.  The originating process is blocked until the
             server responds.

             The server responds to the I_SENDFD request by accepting the
             file descriptor through the I_RECVFD ioctl message.  When this
             happens, the file descriptor associated with the other end of
             the new pipe is transmitted to the originating process as the
             file descriptor returned from open(2) or creat(2).

             If the server does not respond to the I_SENDFD request, the
             stream that the connld module is pushed on becomes uni-
             directional because the server will not be able to retrieve
             any data off the stream until the I_RECVFD request is issued.
             If the server process exits before issuing the I_RECVFD
             request, the open(2) or the creat(2) system calls will fail
             and return -1 to the originating process.

             When the connld module is pushed onto a pipe, messages going
             back and forth through the pipe are ignored by connld.

             On success, an open of connld returns 0.  On failure, errno is
             set to the following values:

             EINVAL       A stream onto which connld is being pushed is not
                          a pipe or the pipe does not have a write queue
                          pointer pointing to a stream head read queue.

             EINVAL       The other end of the pipe onto which connld is
                          being pushed is linked under a multiplexor.





                           Copyright 1994 Novell, Inc.               Page 1

      connld(7)                                                  connld(7)


            EPIPE        connld is being pushed onto a pipe end whose
                         other end is no longer there.

            ENOMEM       An internal pipe could not be created.

            ENXIO        An M_HANGUP message is at the stream head of the
                         pipe onto which connld is being pushed.

            EAGAIN       Internal data structures could not be allocated.

            ENFILE       A file table entry could not be allocated.

      REFERENCES
            streamio(7)


































                          Copyright 1994 Novell, Inc.               Page 2