1.\" Copyright (c) 1983, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" @(#)rwhod.8 8.2 (Berkeley) 12/11/93 29.\" $FreeBSD$ 30.\" 31.Dd July 3, 2017 32.Dt RWHOD 8 33.Os 34.Sh NAME 35.Nm rwhod 36.Nd system status server 37.Sh SYNOPSIS 38.Nm 39.Op Fl i 40.Op Fl p 41.Op Fl l 42.Op Fl m Op Ar ttl 43.Sh DEPRECATION NOTICE 44.Nm 45is deprecated and will be removed from future versions of the 46.Fx 47base system. 48If 49.Nm 50is still required, it can be installed from ports or packages 51(net/bsdrcmds). 52.Sh DESCRIPTION 53The 54.Nm 55utility is the server which maintains the database used by the 56.Xr rwho 1 57and 58.Xr ruptime 1 59programs. 60Its operation is predicated on the ability to 61.Em broadcast 62or 63.Em multicast 64messages on a network. 65.Pp 66The 67.Nm 68utility operates as both a producer and consumer of status information, 69unless the 70.Fl l 71(listen mode) option is specified, in which case 72it acts as a consumer only. 73As a producer of information it periodically 74queries the state of the system and constructs 75status messages which are broadcasted or multicasted on a network. 76As a consumer of information, it listens for other 77.Nm 78servers' status messages, validating them, then recording 79them in a collection of files located in the directory 80.Pa /var/rwho . 81.Pp 82The following options are available: 83.Bl -tag -width indent 84.It Fl i 85Enable insecure mode, which causes 86.Nm 87to ignore the source port on incoming packets. 88.It Fl p 89Ignore all 90.Dv POINTOPOINT 91interfaces. 92This is useful if you do not wish to keep dial on demand 93interfaces permanently active. 94.It Fl l 95Enable listen mode, which causes 96.Nm 97to not broadcast any information. 98This allows you to monitor other machines' 99.Nm 100information, without broadcasting your own. 101.It Fl m Op Ar ttl 102Cause 103.Nm 104to use IP multicast (instead of 105broadcast) on all interfaces that have 106the IFF_MULTICAST flag set in their "ifnet" structs 107(excluding the loopback interface). 108The multicast 109reports are sent with a time-to-live of 1, to prevent 110forwarding beyond the directly-connected subnet(s). 111.Pp 112If the optional 113.Ar ttl 114argument is supplied with the 115.Fl m 116flag, 117.Nm 118will send IP multicast datagrams with a 119time-to-live of 120.Ar ttl , 121via a SINGLE interface rather 122than all interfaces. 123.Ar ttl 124must be between 0 and 12532 (or MAX_MULTICAST_SCOPE). 126Note that 127.Fl m Ar 1 128is different from 129.Fl m , 130in that 131.Fl m Ar 1 132specifies transmission on one interface only. 133.Pp 134When 135.Fl m 136is used without a 137.Ar ttl 138argument, the program accepts multicast 139.Nm 140reports from all multicast-capable interfaces. 141If a 142.Ar ttl 143argument is given, it accepts multicast reports from only one interface, the 144one on which reports are sent (which may be controlled via the host's routing 145table). 146Regardless of the 147.Fl m 148option, the program accepts broadcast or 149unicast reports from all interfaces. 150Thus, this program will hear the 151reports of old, non-multicasting 152.Nm Ns s , 153but, if multicasting is used, 154those old 155.Nm Ns s 156will not hear the reports generated by this program. 157.El 158.Pp 159The server transmits and receives messages at the port indicated 160in the ``who'' service specification; see 161.Xr services 5 . 162The messages sent and received, are of the form: 163.Bd -literal -offset indent 164struct outmp { 165 char out_line[8]; /* tty name */ 166 char out_name[8]; /* user id */ 167 long out_time; /* time on */ 168}; 169 170struct whod { 171 char wd_vers; 172 char wd_type; 173 char wd_fill[2]; 174 int wd_sendtime; 175 int wd_recvtime; 176 char wd_hostname[32]; 177 int wd_loadav[3]; 178 int wd_boottime; 179 struct whoent { 180 struct outmp we_utmp; 181 int we_idle; 182 } wd_we[1024 / sizeof (struct whoent)]; 183}; 184.Ed 185.Pp 186All fields are converted to network byte order prior to 187transmission. 188The load averages are as calculated by the 189.Xr w 1 190program, and represent load averages over the 5, 10, and 15 minute 191intervals prior to a server's transmission; they are multiplied by 100 192for representation in an integer. 193The host name 194included is that returned by the 195.Xr gethostname 3 196system call, with any trailing domain name omitted. 197The array at the end of the message contains information about 198the users logged in to the sending machine. 199This information 200includes the contents of the entry from the user accounting database 201for each non-idle terminal line and a value indicating the 202time in seconds since a character was last received on the terminal line. 203.Pp 204Messages received by the 205.Nm rwho 206server are discarded unless they originated at an 207.Nm rwho 208server's port or the 209.Fl i 210option was specified. 211In addition, if the host's name, as specified 212in the message, contains any unprintable 213.Tn ASCII 214characters, the 215message is discarded. 216Valid messages received by 217.Nm 218are placed in files named 219.Pa whod.hostname 220in the directory 221.Pa /var/rwho . 222These files contain only the most recent message, in the 223format described above. 224.Pp 225Status messages are generated approximately once every 2263 minutes. 227The 228.Nm 229utility performs an 230.Xr nlist 3 231on 232.Pa /boot/kernel/kernel 233every 30 minutes to guard against 234the possibility that this file is not the system 235image currently operating. 236.Sh SEE ALSO 237.Xr ruptime 1 , 238.Xr rwho 1 239.Sh HISTORY 240The 241.Nm 242utility appeared in 243.Bx 4.2 . 244.Sh BUGS 245Status information should be sent only upon request rather than continuously. 246People often interpret the server dying 247or network communication failures 248as a machine going down. 249