CPU(1) CPU(1)
NAME
cpu - connection to CPU server
SYNOPSIS
cpu [ -h server ] [ -u user ] [ -a auth-method ] [ -P
patternfile ] [ -e encryption-hash-algs ] [ -k keypattern ]
[ -c cmd args ... ]
cpu [ -R | -O ]
DESCRIPTION
Cpu starts an rc(1) running on the server machine, or the
machine named in the $cpu environment variable if there is
no -h option. Rc's standard input, output, and error files
will be /dev/cons in the name space where the cpu command
was invoked. Normally, cpu is run in an rio(1) window on a
terminal, so rc output goes to that window, and input comes
from the keyboard when that window is current. Rc's current
directory is the working directory of the cpu command
itself.
The name space for the new rc is an analogue of the name
space where the cpu command was invoked: it is the same
except for architecture-dependent bindings such as /bin and
the use of fast paths to file servers, if available.
If a -u argument is present, cpu uses the argument as the
remote user id.
If a -c argument is present, the remainder of the command
line is executed by rc on the server, and then cpu exits.
If a -P argument is present, the patternfile is passed to
exportfs(4) to control how much of the local name space will
be exported to the remote system.
The -a command allows the user to specify the authentication
mechanism used when connecting to the remote system. The
two possibilities for auth-method are:
p9 This is the default. Authentication is done using
the standard Plan 9 mechanisms, (see authsrv(6)). No
user interaction is required.
netkey Authentication is done using challenge/response and
a hand held authenticator or the netkey program (see
passwd(1)). The user must encrypt the challenge and
type the encryption back to cpu. This is used if the
local host is in a different protection domain than
the server or if the user wants to log into the
server as a different user.
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CPU(1) CPU(1)
The -e option specifies an encryption and/or hash algorithm
to use for the connection. If both are specified, they must
be space separated and comprise a single argument, so they
must be quoted if in a shell command. The default is
`rc4_256' encryption and `sha1' hashing. See ssl(3) for
details on possible algorithms. The argument `clear' speci-
fies no encryption algorithm and can be used to talk to
older versions of the cpu service.
The -k flag specifies a key pattern to use to restrict the
keys selected by the auth_proxy call used for authentica-
tion.
The name space is built by running /usr/$user/lib/profile
with the root of the invoking name space bound to /mnt/term.
The service environment variable is set to cpu; the cputype
and objtype environment variables reflect the server's
architecture.
The -R flag causes cpu to run the server (remote) side of
the protocol. It is run from service files such as
/bin/service/tcp17010. The -O flag is similar but simulates
the pre-9P2000 version of the cpu protocol.
FILES
The name space of the terminal side of the cpu command is
mounted, via exportfs(4), on the CPU side on directory
/mnt/term. The files such as /dev/cons are bound to their
standard locations from there.
SOURCE
/sys/src/cmd/cpu.c
SEE ALSO
rc(1), rio(1), exportfs(4)
BUGS
Binds and mounts done after the terminal lib/profile is run
are not reflected in the new name space.
When using the -a option to `log in' as another user, be
aware that resources in the local name space will be made
available to that user.
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