MUX(3) MUX(3)
NAME
mux - server registry and service multiplexor
SYNOPSIS
bind #s /srv
#s/service1
#s/service2
...
DESCRIPTION
Mux is a replacement for srv(3) that allows a single file
server to provide service to processes on both local and
remote machines. Mux performs all the functions of srv.
Plain files created in the top level directory of mux behave
exactly as described in srv(4).
Creating a directory in mux produces a stream multiplexer.
Many clients may write messages to a single server. Mux
prefixes each message with a connection number to allow the
server to distinguish between clients. Messages written
back to mux by the server are prefixed by a destination con-
nection number. Mux removes the destination connection num-
ber before passing messages back to its clients.
When created, a mux directory contains two files, head and
clone. Opening the clone file allocates a new connection on
the multiplexer. The file descriptor returned is suitable
for mounting (see mount in bind(1) or bind(2)). A file named
by the new connection number is produced by opening the
clone file. The numbered connection file may be used to
read and write messages to the server. The head file should
be used by the server to send and receive message from the
clients.
A file server must be linked with /$objtype/lib/libmux.a to
use the device. The library uses the connection numbers
provided by the driver to map the fid space of the various
client mount drivers into a single fid space for the server.
Libmux replaces convS2M and convM2S (see fcall(2)) from the
C library. A server linked with libmux will work correctly
with a normal srv entry.
Mux's only use is to allow CPU servers to act as a gateway
to a file system. It is not normally configured in a sys-
tem.
BUGS
This should be unnecessary but is required to overcome a
Page 1 Plan 9 (printed 4/19/24)
MUX(3) MUX(3)
failure of vision.
SEE ALSO
bind(2), srv(4)
Page 2 Plan 9 (printed 4/19/24)