connld(7)							     connld(7)

NAME    [Toc]    [Back]

     connld - line discipline for unique stream	connections

DESCRIPTION    [Toc]    [Back]

     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 filesystem 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 filesystem	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
     can not 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.

     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.





									Page 1






connld(7)							     connld(7)



     ENFILE	  A file table entry could not be allocated.

SEE ALSO    [Toc]    [Back]

     streamio(7).


									PPPPaaaaggggeeee 2222