[apple/network_cmds.git] / rwhod.tproj / rwhod.8

.\" 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. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"	This product includes software developed by the University of
.\"	California, Berkeley and its contributors.
.\" 4. 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.
.\"
.\"     @(#)rwhod.8	8.2 (Berkeley) 12/11/93
.\"
.Dd December 11, 1993
.Dt RWHOD 8
.Os BSD 4.2
.Sh NAME
.Nm rwhod
.Nd system status server
.Sh SYNOPSIS
.Nm rwhod
.Sh DESCRIPTION
.Nm Rwhod
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
.Nm Rwhod
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 rwhod
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 ``rwho'' 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 */
	long	out_time;		/* time on */
};

struct	whod {
	char	wd_vers;
	char	wd_type;
	char	wd_fill[2];
	int	wd_sendtime;
	int	wd_recvtime;
	char	wd_hostname[32];
	int	wd_loadav[3];
	int	wd_boottime;
	struct	whoent {
		struct	outmp we_utmp;
		int	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 2
system 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
server are discarded unless they originated at an
.Xr rwho
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 rwhod
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 approximately once every
3 minutes.
.Nm Rwhod
performs an
.Xr nlist 3
on
.Pa /vmunix
every 30 minutes to guard against
the possibility that this file is not the system
image currently operating.
.Sh SEE ALSO
.Xr rwho 1 ,
.Xr ruptime 1
.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.
.Sh HISTORY
The
.Nm
command appeared in
.Bx 4.2 .
Commit	Line	Data
b7080c8e A	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. All advertising materials mentioning features or use of this software
	13	.\" must display the following acknowledgement:
	14	.\" This product includes software developed by the University of
	15	.\" California, Berkeley and its contributors.
	16	.\" 4. Neither the name of the University nor the names of its contributors
	17	.\" may be used to endorse or promote products derived from this software
	18	.\" without specific prior written permission.
	19	.\"
	20	.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	21	.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	22	.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	23	.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	24	.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	25	.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	26	.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	27	.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	28	.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	29	.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	30	.\" SUCH DAMAGE.
	31	.\"
	32	.\" @(#)rwhod.8 8.2 (Berkeley) 12/11/93
	33	.\"
	34	.Dd December 11, 1993
	35	.Dt RWHOD 8
	36	.Os BSD 4.2
	37	.Sh NAME
	38	.Nm rwhod
	39	.Nd system status server
	40	.Sh SYNOPSIS
	41	.Nm rwhod
	42	.Sh DESCRIPTION
	43	.Nm Rwhod
	44	is the server which maintains the database used by the
	45	.Xr rwho 1
	46	and
	47	.Xr ruptime 1
	48	programs. Its operation is predicated on the ability to
	49	.Em broadcast
	50	messages on a network.
	51	.Pp
	52	.Nm Rwhod
	53	operates as both a producer and consumer of status information.
	54	As a producer of information it periodically
	55	queries the state of the system and constructs
	56	status messages which are broadcast on a network.
	57	As a consumer of information, it listens for other
	58	.Nm rwhod
	59	servers' status messages, validating them, then recording
	60	them in a collection of files located in the directory
	61	.Pa /var/rwho .
	62	.Pp
	63	The server transmits and receives messages at the port indicated
	64	in the ``rwho'' service specification; see
65	.Xr services 5 .
66	The messages sent and received, are of the form:
67	.Bd -literal -offset indent
68	struct outmp {
69	char out_line[8]; /* tty name */
70	char out_name[8]; /* user id */
71	long out_time; /* time on */
72	};
73
74	struct whod {
75	char wd_vers;
76	char wd_type;
77	char wd_fill[2];
78	int wd_sendtime;
79	int wd_recvtime;
80	char wd_hostname[32];
81	int wd_loadav[3];
82	int wd_boottime;
83	struct whoent {
84	struct outmp we_utmp;
85	int we_idle;
86	} wd_we[1024 / sizeof (struct whoent)];
87	};
88	.Ed
89	.Pp
90	All fields are converted to network byte order prior to
91	transmission. The load averages are as calculated by the
92	.Xr w 1
93	program, and represent load averages over the 5, 10, and 15 minute
94	intervals prior to a server's transmission; they are multiplied by 100
95	for representation in an integer. The host name
96	included is that returned by the
97	.Xr gethostname 2
98	system call, with any trailing domain name omitted.
99	The array at the end of the message contains information about
100	the users logged in to the sending machine. This information
101	includes the contents of the
102	.Xr utmp 5
103	entry for each non-idle terminal line and a value indicating the
104	time in seconds since a character was last received on the terminal line.
105	.Pp
106	Messages received by the
107	.Xr rwho
108	server are discarded unless they originated at an
109	.Xr rwho
110	server's port. In addition, if the host's name, as specified
111	in the message, contains any unprintable
112	.Tn ASCII
113	characters, the
114	message is discarded. Valid messages received by
115	.Nm rwhod
116	are placed in files named
117	.Pa whod.hostname
118	in the directory
119	.Pa /var/rwho .
120	These files contain only the most recent message, in the
121	format described above.
122	.Pp
123	Status messages are generated approximately once every
124	3 minutes.
125	.Nm Rwhod
126	performs an
127	.Xr nlist 3
128	on
129	.Pa /vmunix
130	every 30 minutes to guard against
131	the possibility that this file is not the system
132	image currently operating.
133	.Sh SEE ALSO
134	.Xr rwho 1 ,
135	.Xr ruptime 1
136	.Sh BUGS
137	There should be a way to relay status information between networks.
138	Status information should be sent only upon request rather than continuously.
139	People often interpret the server dying
140	or network communication failures
141	as a machine going down.
142	.Sh HISTORY
143	The
144	.Nm
145	command appeared in
146	.Bx 4.2 .