rwhod - The system status server
/usr/sbin/rwhod [-b | -l]
Sets the broadcast only mode. Sends outgoing rwho packets,
but ignores incoming ones. Sets the listen only
mode. Collects incoming rwho packets from the network,
but does not broadcast rwho data.
The rwhod daemon is the server that maintains the database
used by the rwho(1) and ruptime(1) programs. Its operation
is predicated on the ability to broadcast messages on
a network.
The rwhod server 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 rwhod
servers' status messages, validating them, then recording
them in a collection of files located in the /var/rwho
directory.
The server transmits and receives messages at the port
indicated in the rwho service specification; see services(4). The messages sent and received have the following
format:
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)]; };
All fields are converted to network byte order prior to
transmission. The load averages are as calculated by the
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 hostname included is that returned by the
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
utmp(4) entry for each nonidle terminal line and a value
indicating the time in seconds since a character was last
received on the terminal line.
Messages received by the rwho server are discarded unless
they originated at an 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 rwhod are placed in files named
whod.hostname in the /var/rwho directory. These files
contain only the most recent message, in the format previously
described.
Status messages are generated approximately once every 3
minutes. rwhod performs an nlist(3) on /vmunix every 30
minutes to guard against the possibility that this file is
not the system image currently operating.
Specifies the command path Contains the most recent valid
message received by rwhod from hostname.
Commands: rwho(1), ruptime(1)
rwhod(8)
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