\" Copyright (c) 1983, 1991, 1993
\"      The Regents of the University of California.  All rights reserved.
\"
\" Redistribution and use in source and binary forms, with or without
\" modification, are permitted provided that the following conditions
\" are met:
\" 1. Redistributions of source code must retain the above copyright
\"    notice, this list of conditions and the following disclaimer.
\" 2. Redistributions in binary form must reproduce the above copyright
\"    notice, this list of conditions and the following disclaimer in the
\"    documentation and/or other materials provided with the distribution.
\" 3. Neither the name of the University nor the names of its contributors
\"    may be used to endorse or promote products derived from this software
\"    without specific prior written permission.
\"
\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
\" SUCH DAMAGE.
\"
\"     from: @(#)rwhod.8        8.2 (Berkeley) 12/11/93
\"      $NetBSD: rwhod.8,v 1.20 2005/09/12 18:33:56 wiz Exp $
\"
Dd September 12, 2005
Dt RWHOD 8
Os
Sh NAME
Nm rwhod
Nd system status server
Sh SYNOPSIS
Nm
Op Fl i Ar interval
Op Fl u Ar user
Sh DESCRIPTION
Nm
is the server which maintains the database used by the
Xr rwho 1
and
Xr ruptime 1
programs.
Its operation is predicated on the ability to
Em broadcast
messages on a network.
Pp
The following options are available:
Bl -tag -width XXXXXXXXXXX
It Fl i Ar interval
Allows for the broadcast interval to be changed from the default 3 minutes.
The
Ar interval
argument is the number of seconds to change the interval to, or if the
value is suffixed by
Dq m
then it is interpreted as minutes.
The maximum allowed value for the broadcast interval is 11 minutes
because higher values will cause
Xr ruptime 1
to mark the host as being down.
It Fl u Ar user
Drop privileges and become the user
Ar user .
El
Pp
Nm
operates as both a producer and consumer of status information.
As a producer of information it periodically
queries the state of the system and constructs
status messages which are broadcast on a network.
As a consumer of information, it listens for other
Nm
servers' status messages, validating them, then recording
them in a collection of files located in the directory
Pa /var/rwho .
Pp
The server transmits and receives messages at the port indicated
in the
Dq who
service specification; see
Xr services 5 .
The messages sent and received, are of the form:
Bd -literal -offset indent
struct  outmp {
       char    out_line[8];            /* tty name */
       char    out_name[8];            /* user id */
       int32_t out_time;               /* time on */
};

struct  whod {
       char    wd_vers;
       char    wd_type;
       char    wd_fill[2];
       int32_t wd_sendtime;
       int32_t wd_recvtime;
       char    wd_hostname[32];
       int32_t wd_loadav[3];
       int32_t wd_boottime;
       struct  whoent {
               struct  outmp we_utmp;
               int32_t we_idle;
       } wd_we[1024 / sizeof (struct whoent)];
};
Ed
Pp
All fields are converted to network byte order prior to
transmission.
The load averages are as calculated by the
Xr w 1
program, and represent load averages over the 5, 10, and 15 minute
intervals prior to a server's transmission; they are multiplied by 100
for representation in an integer.
The host name included is that returned by the
Xr gethostname 3
function call, with any trailing domain name omitted.
The array at the end of the message contains information about
the users logged in to the sending machine.
This information includes the contents of the
Xr utmp 5
entry for each non-idle terminal line and a value indicating the
time in seconds since a character was last received on the terminal line.
Pp
Messages received by the
Xr rwho 1
server are discarded unless they originated at an
Xr rwho 1
server's port.
In addition, if the host's name, as specified
in the message, contains any unprintable
Tn ASCII
characters, the message is discarded.
Valid messages received by
Nm
are placed in files named
Pa whod.hostname
in the directory
Pa /var/rwho .
These files contain only the most recent message, in the
format described above.
Pp
Status messages are generated by default approximately once every
3 minutes.
Sh SEE ALSO
Xr ruptime 1 ,
Xr rwho 1
Sh HISTORY
The
Nm
command appeared in
Bx 4.2 .
Sh BUGS
There should be a way to relay status information between networks.
Status information should be sent only upon request rather than continuously.
People often interpret the server dying or network communication
failures as a machine going down.

You are viewing proxied material from ftp.icm.edu.pl. The copyright of proxied material belongs to its original authors. Any comments or complaints in relation to proxied material should be directed to the original authors of the content concerned. Please see the disclaimer for more details.