.\" Copyright (c) 1983 Regents of the University of California.
.\" All rights reserved. The Berkeley software License Agreement
.\" specifies the terms and conditions for redistribution.
.\" @(#)rcmd.3 6.1 (Berkeley) %G%
rcmd, rresvport, ruserok \- routines for returning a stream to a remote command
.B "rem = rcmd(ahost, inport, locuser, remuser, cmd, fd2p);"
.B "char *locuser, *remuser, *cmd;"
.B "ruserok(rhost, superuser, ruser, luser);"
is a routine used by the super-user to execute a command on
a remote machine using an authentication scheme based
on reserved port numbers.
is a routine which returns a descriptor to a socket
with an address in the privileged port space.
is a routine used by servers
to authenticate clients requesting service with
All three functions are present in the same file and are used
returning \-1 if the host does not exist.
is set to the standard name of the host
and a connection is established to a server
residing at the well-known Internet port
If the call succeeds, a socket of type SOCK_STREAM
is returned to the caller, and given to the remote
is non-zero, then an auxiliary channel to a control
process will be set up, and a descriptor for it will be placed
The control process will return diagnostic
output from the command (unit 2) on this channel, and will also
accept bytes on this channel as being UNIX signal numbers, to be
forwarded to the process group of the command.
command) will be made the same as the
provision is made for sending arbitrary signals to the remote process,
although you may be able to get its attention by using out-of-band data.
The protocol is described in detail in
routine is used to obtain a socket with a privileged
address bound to it. This socket is suitable for use
and sevral other routines. Privileged addresses consist
of a port in the range 0 to 1023. Only the super-user
is allowed to bind an address of this sort to a socket.
takes a remote host's name, as returned by a
routine, two user names and a flag indicating if
the local user's name is the super-user. It then
in the current working directory (normally the local
user's home directory) to see if the request for
service is allowed. A 1 is returned if the machine
name is listed in the ``hosts.equiv'' file, or the
host and remote user name are found in the ``.rhosts''
flag is 1, the checking of the ``host.equiv'' file is
There is no way to specify options to the