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 subse-
     quently 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 ori-
     ginating 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 mes-
     sage identical to that for the ioctl ISENDFD [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 ISENDFD request by accepting the file
     descriptor through the IRECVFD 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 ISENDFD 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 IRECVFD request is issued. If the server process exits before
     issuing the IRECVFD 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 multiplexer.

     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 MHANGUP 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.



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connld(7)                                                         connld(7)

SEE ALSO
     streamio(7).

     Programmer's Guide: STREAMS


















































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