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.\" @(#)rwhod.8 6.5 (Berkeley) 3/16/91
is the server which maintains the database used by the
programs. Its operation is predicated on the ability to
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
servers' status messages, validating them, then recording
them in a collection of files located in the directory
The server transmits and receives messages at the port indicated
in the ``rwho'' service specification; see
The messages sent and received, are of the form:
.Bd -literal -offset indent
char out_line[8]; /* tty name */
char out_name[8]; /* user id */
long out_time; /* time on */
} wd_we[1024 / sizeof (struct whoent)];
All fields are converted to network byte order prior to
transmission. The load averages are as calculated by the
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
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
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.
server are discarded unless they originated at an
server's port. In addition, if the host's name, as specified
in the message, contains any unprintable
message is discarded. Valid messages received by
are placed in files named
These files contain only the most recent message, in the
Status messages are generated approximately once every
every 30 minutes to guard against
the possibility that this file is not the system
image currently operating.
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 communtication failures