rcmd(3X)                       DG/UX 5.4R3.00                       rcmd(3X)


NAME
       rcmd, rresvport, ruserok - routines for returning a stream to a
       remote command

SYNOPSIS
       rem = rcmd(ahost, inport, locuser, remuser, cmd, fd2p);
       char **ahost;
       ushort inport;
       char *locuser, *remuser, *cmd;
       int *fd2p;

       s = rresvport(port);
       int *port;

       ruserok(rhost, superuser, ruser, luser);
       char *rhost;
       int superuser;
       char *ruser, *luser;

DESCRIPTION
       rcmd 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.  rresvport is a routine which returns a descriptor to a
       socket with an address in the privileged port space.  ruserok is a
       routine used by servers to authenticate clients requesting service
       with rcmd.

       rcmd looks up the host *ahost using gethostbyname(3N), returning -1
       if the host does not exist.  Otherwise *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 inport.

       If the call succeeds, a socket of type SOCK_STREAM is returned to the
       caller, and given to the remote command as stdin and stdout.  If fd2p
       is non-zero, then an auxiliary channel to a control process will be
       set up, and a descriptor for it will be placed in *fd2p.  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
       DG/UX system signal numbers, to be forwarded to the process group of
       the command.  If fd2p is 0, then the stderr (unit 2 of the remote
       command) will be made the same as the stdout and no 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 rresvport routine is used to obtain a socket with a privileged
       address bound to it.  This socket is suitable for use by rcmd 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.

       ruserok takes a remote host's name, as returned by a gethostent(3N)
       routine, two user names and a flag indicating if the local user's
       name is the super-user.  It then checks the files /etc/hosts.equiv
       and, possibly, .rhosts in the local user's home directory to see if



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rcmd(3X)                       DG/UX 5.4R3.00                       rcmd(3X)


       the request for service is allowed.  A 0 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'' file; otherwise ruserok
       returns -1.  If the superuser flag is 1, the checking of the
       ``host.equiv'' file is bypassed.

SEE ALSO
       rlogin(1C), rsh(1C), rexecd(1M), rlogind(1M), rexec(3X).

NOTE
       There is no way to specify options to the socket call that rcmd
       makes.













































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