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Annotation of cci/usr/src/man/man3/rcmd.3x, revision 1.1

1.1     ! root        1: .TH RCMD 3X "17 March 1982"
        !             2: .UC 4
        !             3: .SH NAME
        !             4: rcmd, rresvport, ruserok \- routines for returning a stream to a remote command
        !             5: .SH SYNOPSIS
        !             6: .nf
        !             7: .B "rem = rcmd(ahost, inport, locuser, remuser, cmd, fd2p);"
        !             8: .B char **ahost;
        !             9: .B u_short inport;
        !            10: .B "char *locuser, *remuser, *cmd;"
        !            11: .B int *fd2p;
        !            12: .PP
        !            13: .B s = rresvport(port);
        !            14: .B int *port;
        !            15: .PP
        !            16: .B "ruserok(rhost, superuser, ruser, luser);"
        !            17: .B char *rhost;
        !            18: .B int superuser;
        !            19: .B char *ruser, *luser;
        !            20: .fi
        !            21: .SH DESCRIPTION
        !            22: .I Rcmd
        !            23: is a routine used by the super-user to execute a command on
        !            24: a remote machine using an authentication scheme based
        !            25: on reserved port numbers.
        !            26: .I Rresvport
        !            27: is a routine which returns a descriptor to a socket
        !            28: with an address in the privileged port space.
        !            29: .I Ruserok
        !            30: is a routine used by servers
        !            31: to authenticate clients requesting service with
        !            32: .IR rcmd .
        !            33: All three functions are present in the same file and are used
        !            34: by the
        !            35: .IR rshd (8C)
        !            36: server (among others).
        !            37: .PP
        !            38: .I Rcmd
        !            39: looks up the host
        !            40: .I *ahost
        !            41: using
        !            42: .IR gethostbyname (3N),
        !            43: returning \-1 if the host does not exist.
        !            44: Otherwise
        !            45: .I *ahost
        !            46: is set to the standard name of the host
        !            47: and a connection is established to a server
        !            48: residing at the well-known Internet port
        !            49: .IR inport .
        !            50: .PP
        !            51: If the call succeeds, a socket of type SOCK_STREAM
        !            52: is returned to the caller, and given to the remote
        !            53: command as 
        !            54: .B stdin
        !            55: and
        !            56: .BR stdout .
        !            57: If
        !            58: .I fd2p
        !            59: is non-zero, then an auxiliary channel to a control
        !            60: process will be set up, and a descriptor for it will be placed
        !            61: in
        !            62: .IR *fd2p .
        !            63: The control process will return diagnostic
        !            64: output from the command (unit 2) on this channel, and will also
        !            65: accept bytes on this channel as being UNIX signal numbers, to be
        !            66: forwarded to the process group of the command.
        !            67: If
        !            68: .I fd2p
        !            69: is 0, then the 
        !            70: .B stderr
        !            71: (unit 2 of the remote
        !            72: command) will be made the same as the 
        !            73: .B stdout
        !            74: and no
        !            75: provision is made for sending arbitrary signals to the remote process,
        !            76: although you may be able to get its attention by using out-of-band data.
        !            77: .PP
        !            78: The protocol is described in detail in
        !            79: .IR rshd (8C).
        !            80: .PP
        !            81: The
        !            82: .I rresvport
        !            83: routine is used to obtain a socket with a privileged
        !            84: address bound to it.  This socket is suitable for use
        !            85: by 
        !            86: .I rcmd
        !            87: and sevral other routines.  Privileged addresses consist
        !            88: of a port in the range 0 to 1023.  Only the super-user
        !            89: is allowed to bind an address of this sort to a socket.
        !            90: .PP
        !            91: .I Ruserok
        !            92: takes a remote host's name, as returned by a
        !            93: .IR gethostent (3N)
        !            94: routine, two user names and a flag indicating if
        !            95: the local user's name is the super-user.  It then
        !            96: checks the files 
        !            97: .I /etc/hosts.equiv
        !            98: and, possibly, 
        !            99: .I .rhosts
        !           100: in the current working directory (normally the local
        !           101: user's home directory) to see if the request for
        !           102: service is allowed.  A 1 is returned if the machine
        !           103: name is listed in the ``hosts.equiv'' file, or the
        !           104: host and remote user name are found in the ``.rhosts''
        !           105: file; otherwise 
        !           106: .I ruserok
        !           107: returns 0.  If the
        !           108: .I superuser
        !           109: flag is 1, the checking of the ``host.equiv'' file is
        !           110: bypassed.
        !           111: .SH SEE ALSO
        !           112: rlogin(1C),
        !           113: rsh(1C),
        !           114: rexec(3X),
        !           115: rexecd(8C),
        !           116: rlogind(8C),
        !           117: rshd(8C)
        !           118: .SH BUGS
        !           119: There is no way to specify options to the
        !           120: .I socket
        !           121: call
        !           122: which
        !           123: .I rcmd
        !           124: makes.

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