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connld is a STREAMS-based module that provides unique connections between server and client processes. It can only be pushed (see streamio(7I)) onto one end of a STREAMS-based pipe that may subsequently be attached to a name in the file system name space with
fattach(3C). 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(7I)) 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) invocation will fail and return -1 to the originating
process.
When the connld module is pushed onto a pipe, it ignores messages going back and forth through the pipe.
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