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rwhod(8) [bsd man page]

RWHOD(8)						      System Manager's Manual							  RWHOD(8)

NAME
rwhod - system status server SYNOPSIS
/usr/sbin/rwhod DESCRIPTION
Rwhod is the server which 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. 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 rwhod servers' status messages, validating them, then recording them in a collection of files located in the directory /usr/spool/rwho. The server transmits and receives messages at the port indicated in the ``rwho'' service specification; see services(5). The messages sent and received, are of the form: 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 { structoutmp 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 repre- sent 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 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 con- tents of the 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. 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 directory /usr/spool/rwho. These files contain only the most recent message, in the format described above. 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. SEE ALSO
rwho(1), ruptime(1) BUGS
There should be a way to relay status information between networks. Status information should be sent only upon request rather than con- tinuously. People often interpret the server dying or network communtication failures as a machine going down. 4.2 Berkeley Distribution November 16, 1996 RWHOD(8)

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rwhod(8)						      System Manager's Manual							  rwhod(8)

NAME
rwhod - The system status server SYNOPSIS
rwhod [-b|-l] FLAGS
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. DESCRIPTION
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, are of the form: 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 repre- sent load averages over the 5-, 10-, and 15-minute intervals prior to a server's transmission; they are multiplied by 100 for representa- tion 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 con- tents 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. FILES
Specifies the command path RELATED INFORMATION
Commands: rwho(1), ruptime(1) delim off rwhod(8)

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