[unix-history] / usr / man / man8 / rwhod.8c

.TH RWHOD 8C "4 March 1983"
.UC 4
.SH NAME
rwhod \- system status server
.SH SYNOPSIS
.B /etc/rwhod
.SH DESCRIPTION
.I Rwhod
is the server which maintains the database used by the
.IR rwho (1C)
and
.IR ruptime (1C)
programs.  Its operation is predicated on the ability to
.I broadcast
messages on a network.
.PP
.I 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
.I rwhod
servers' status messages, validating them, then recording
them in a collection of files located in the directory
.IR /usr/spool/rwho .
.PP
The
.I rwho
server transmits and receives messages at the port indicated
in the ``rwho'' service specification, see 
.IR services (5).
The messages sent and received, are of the form:
.PP
.nf
.ta 0.5i 1.0i 1.5i
struct	outmp {
	char	out_line[8];		/* tty name */
	char	out_name[8];		/* user id */
	long	out_time;		/* time on */
};
.sp
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)];
};
.fi
.PP
All fields are converted to network byte order prior to
transmission.  The load averages are as calculated by the
.IR w (1)
program, and represent load averages over the 5, 10, and 15 minute 
intervals prior to a server's transmission.  The host name
included is that returned by the
.IR gethostname (2)
system call.
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 
.IR utmp (5)
entry for each non-idle terminal line and a value indicating the
time since a character was last received on the terminal line.
.PP
Messages received by the
.I rwho
server are discarded unless they originated at a
.I rwho
server's port.  In addition, if the host's name, as specified
in the message, contains any unprintable ASCII characters, the
message is discarded.  Valid messages received by
.I rwhod
are placed in files named
.IR whod . hostname
in the directory
.IR /usr/spool/rwho .
These files contain only the most recent message, in the
format described above.
.PP
Status messages are generated approximately once every
60 seconds.  
.I Rwhod
performs an
.IR nlist (3)
on /vmunix every 10 minutes to guard against
the possibility that this file is not the system
image currently operating.
.SH "SEE ALSO"
rwho(1C),
ruptime(1C)
.SH BUGS
Should relay status information between networks. 
People often interpret the server dieing
as a machine going down.
Commit	Line	Data
0d5912d8 C	1	.TH RWHOD 8C "4 March 1983"
	2	.UC 4
	3	.SH NAME
	4	rwhod \- system status server
	5	.SH SYNOPSIS
	6	.B /etc/rwhod
	7	.SH DESCRIPTION
	8	.I Rwhod
	9	is the server which maintains the database used by the
	10	.IR rwho (1C)
	11	and
	12	.IR ruptime (1C)
	13	programs. Its operation is predicated on the ability to
	14	.I broadcast
	15	messages on a network.
	16	.PP
	17	.I Rwhod
	18	operates as both a producer and consumer of status information.
	19	As a producer of information it periodically
	20	queries the state of the system and constructs
	21	status messages which are broadcast on a network.
	22	As a consumer of information, it listens for other
	23	.I rwhod
	24	servers' status messages, validating them, then recording
	25	them in a collection of files located in the directory
	26	.IR /usr/spool/rwho .
	27	.PP
	28	The
	29	.I rwho
	30	server transmits and receives messages at the port indicated
	31	in the ``rwho'' service specification, see
	32	.IR services (5).
	33	The messages sent and received, are of the form:
	34	.PP
	35	.nf
	36	.ta 0.5i 1.0i 1.5i
	37	struct outmp {
	38	char out_line[8]; /* tty name */
	39	char out_name[8]; /* user id */
	40	long out_time; /* time on */
	41	};
	42	.sp
	43	struct whod {
	44	char wd_vers;
	45	char wd_type;
	46	char wd_fill[2];
	47	int wd_sendtime;
	48	int wd_recvtime;
	49	char wd_hostname[32];
	50	int wd_loadav[3];
	51	int wd_boottime;
	52	struct whoent {
	53	struct outmp we_utmp;
	54	int we_idle;
	55	} wd_we[1024 / sizeof (struct whoent)];
	56	};
	57	.fi
	58	.PP
	59	All fields are converted to network byte order prior to
	60	transmission. The load averages are as calculated by the
	61	.IR w (1)
	62	program, and represent load averages over the 5, 10, and 15 minute
	63	intervals prior to a server's transmission. The host name
	64	included is that returned by the
65	.IR gethostname (2)
66	system call.
67	The array at the end of the message contains information about
68	the users logged in to the sending machine. This information
69	includes the contents of the
70	.IR utmp (5)
71	entry for each non-idle terminal line and a value indicating the
72	time since a character was last received on the terminal line.
73	.PP
74	Messages received by the
75	.I rwho
76	server are discarded unless they originated at a
77	.I rwho
78	server's port. In addition, if the host's name, as specified
79	in the message, contains any unprintable ASCII characters, the
80	message is discarded. Valid messages received by
81	.I rwhod
82	are placed in files named
83	.IR whod . hostname
84	in the directory
85	.IR /usr/spool/rwho .
86	These files contain only the most recent message, in the
87	format described above.
88	.PP
89	Status messages are generated approximately once every
90	60 seconds.
91	.I Rwhod
92	performs an
93	.IR nlist (3)
94	on /vmunix every 10 minutes to guard against
95	the possibility that this file is not the system
96	image currently operating.
97	.SH "SEE ALSO"
98	rwho(1C),
99	ruptime(1C)
100	.SH BUGS
101	Should relay status information between networks.
102	People often interpret the server dieing
103	as a machine going down.