.\"	$OpenBSD: rcmdsh.3,v 1.6 1999/07/05 04:41:00 aaron Exp $
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.\" $FreeBSD: src/lib/libc/net/rcmdsh.3,v 1.7 2007/01/09 00:28:02 imp Exp $
.\"
.Dd December 31, 2017
.Dt RCMDSH 3
.Os
.Sh NAME
.Nm rcmdsh
.Nd return a stream to a remote command without superuser
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In unistd.h
.Ft int
.Fo rcmdsh
.Fa "char **ahost"
.Fa "int inport"
.Fa "const char *locuser"
.Fa "const char *remuser"
.Fa "const char *cmd"
.Fa "const char *rshprog"
.Fc
.Sh DESCRIPTION
The
.Fn rcmdsh
function
is used by normal users to execute a command on
a remote machine using an authentication scheme based
on reserved port numbers using
.Xr rshd 8 Pq Pa net/bsdrcmds
or the value of
.Fa rshprog
(if
.No non- Ns Dv NULL ) .
.Pp
The
.Fn rcmdsh
function
looks up the host
.Fa *ahost
using
.Xr gethostbyname 3 ,
returning \-1 if the host does not exist.
Otherwise
.Fa *ahost
is set to the standard name of the host
and a connection is established to a server
residing at the well-known Internet port
.Dq Li shell/tcp
(or whatever port is used by
.Fa rshprog ) .
The
.Fa inport
argument
is ignored; it is only included to provide an interface similar to
.Xr rcmd 3 .
.Pp
If the connection succeeds,
a socket in the
.Ux
domain of type
.Dv SOCK_STREAM
is returned to the caller, and given to the remote
command as
.Dv stdin , stdout ,
and
.Dv stderr .
.Sh RETURN VALUES
The
.Fn rcmdsh
function
returns a valid socket descriptor on success.
Otherwise, \-1 is returned
and a diagnostic message is printed on the standard error.
.Sh SEE ALSO
.Xr rsh 1 Pq Pa net/bsdrcmds ,
.Xr socketpair 2 ,
.Xr rcmd 3 ,
.Xr rshd 8
.Sh HISTORY
The
.Fn rcmdsh
function first appeared in
.Ox 2.0 ,
and made its way into
.Fx 4.6 .
.Sh BUGS
If
.Xr rsh 1
encounters an error, a file descriptor is still returned instead of \-1.