tirdwr(7M)
NAME
tirdwr - Transport Interface read/write interface STREAMS
module
SYNOPSIS
int ioctl( fd, I_PUSH, "tirdwr");
DESCRIPTION
tirdwr is a STREAMS module that provides an alternate
interface to a transport provider which supports the Tran-
sport Interface ("TI") functions of the Network Services
library (see Section 3N). This alternate interface allows a
user to communicate with the transport protocol provider
using the read(2) and write(2) system calls. The
putmsg(2) and getmsg(2) system calls may also be used. How-
ever, putmsg and getmsg can only transfer data messages
between user and stream; control portions are disallowed.
The tirdwr module must only be pushed (see I_PUSH in
streamio(7I)) onto a stream terminated by a transport proto-
col provider which supports the TI. After the tirdwr module
has been pushed onto a stream, none of the TI functions can
be used. Subsequent calls to TI functions cause an error on
the stream. Once the error is detected, subsequent system
calls on the stream return an error with errno set to
EPROTO.
The following are the actions taken by the tirdwr module
when pushed on the stream, popped (see I_POP in
streamio(7I)) off the stream, or when data passes through
it.
push When the module is pushed onto a stream, it checks any
existing data destined for the user to ensure that
only regular data messages are present. It ignores any
messages on the stream that relate to process manage-
ment, such as messages that generate signals to the
user processes associated with the stream. If any
other messages are present, the I_PUSH will return an
error with errno set to EPROTO.
write The module takes the following actions on data that
originated from a write system call:
o All messages with the exception of messages that
contain control portions (see the putmsg and
getmsg system calls) are transparently passed
onto the module's downstream neighbor.
o Any zero length data messages are freed by the
module and they will not be passed onto the
module's downstream neighbor.
o Any messages with control portions generate an
error, and any further system calls associated
with the stream fails with errno set to EPROTO.
read The module takes the following actions on data that
originated from the transport protocol provider.
All messages with the exception of those that contain
control portions (see the putmsg and getmsg system
calls) are transparently passed onto the module's
upstream neighbor. The action taken on messages with
control portions will be as follows:
o Any data messages with control portions
have the control portions removed from the
message before to passing the message on to
the upstream neighbor.
o Messages that represent an orderly release
indication from the transport provider gen-
erate a zero length data message, indicat-
ing the end of file, which will be sent to
the reader of the stream. The orderly
release message itself is freed by the
module.
o Messages that represent an abortive discon-
nect indication from the transport provider
cause all further write and putmsg system
calls to fail with errno set to ENXIO. All
further read and getmsg system calls return
zero length data (indicating end of file)
once all previous data has been read.
o With the exception of the above rules, all
other messages with control portions gen-
erate an error and all further system calls
associated with the stream will fail with
errno set to EPROTO.
Any zero length data messages are freed by the module
and they are not passed onto the module's upstream
neighbor.
pop When the module is popped off the stream or the stream
is closed, the module takes the following action:
o If an orderly release indication has been previ-
ously received, then an orderly release request
will be sent to the remote side of the transport
connection.
SEE ALSO
intro(3), getmsg(2), putmsg(2), read(2), write(2), intro(3),
streamio(7I), timod(7M)
STREAMS Programming Guide
Man(1) output converted with
man2html