Sun Microsystems Sun Workstation 100U System Manager's Manual page 244

RWHOD(8C)
MAINTENANCE COMMANDS
RWHOD(8C)
NAME
rwhod - system status server
SYNOPSIS
/ete/rwhod
DESCRIPTION
Rwhod is the server which maintains the database used by the rwho(IC) and ruptime(IC)
pr~
grams. Its operation is predicated on the ability to hroadca8t messages on a network.
Rwhod operates as both a producer and consumer of status information. As a producer of infor-
mation 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 rwhod servers' status
messages, validating them, then recording them in a collection of files located in the directory
I u8rl 8poollrwho.
The rwho server transmits and receives messages at the port indicated in the "rwho" service
specification, see 8ervice8(5). The messages sent and received, are of the form:
struct outmp {
char out_line(8);
1*
tty name
*1
char out_name(8);
' *
user id
*1
long out_time;
1*
time on
*'
};
struct whod {
char wd_vers;
char wd_type;
char wd_fill(2J;
int wd_sendtime;
int wd_recvtime;
char wd_hostname(32J;
int wd_Ioadav{3J;
int wd_boottime;
struct whoent {
struct outmp we_utmp;
int we_idle;
} wd_we[1024 , sizeof (struct whoent)J;
};
All
fields are converted to network byte order prior to transmission. The load averages are as cal-
culated by the
w(l)
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 getho8tname(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 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.
Messages received by the rwho server are discarded unless they originated at a rwho server's port.
In addition, if the host's name, as specified in the message, contains any unprintable ASCII char-
acters, the message is discarded. Valid messages received by rwhod are placed in files named
whod.ho8tname in the directory IU8rl8poollrwho. These files contain only the most recent mes-
sage, in the format described above.
Status messages are generated approximately once every 60 seconds. Rwhod performs an nlist(3)
on Ivmunix every 10 minutes to guard against the possibility that this file is not the system
image currently operatillg.
Sun Release 1.1 Last change: 28 October 1983 89