rwhod(8c) — AIX PS/2 1.2.1



RWHOD(8c,C)                 AIX TCP/IP User's Guide                 RWHOD(8c,C)



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rwhod



PURPOSE

Provides the server function which maintains the database used by the rwho and
ruptime programs.

SYNTAX


/etc/rwhod ---|


DESCRIPTION

The rwhod command is the server which maintains the database used by the rwho
and ruptime programs.  Its operation is predicated on the ability to broadcast
messages on a network.

The rwhod command 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 "rc.tcpip, rc.tcpip.local").  The messages sent and
received, are of the form:























Processed October 29, 1990        RWHOD(8c,C)                                 1



RWHOD(8c,C)                 AIX TCP/IP User's Guide                 RWHOD(8c,C)



  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)];
  };



































Processed October 29, 1990        RWHOD(8c,C)                                 2



RWHOD(8c,C)                 AIX TCP/IP User's Guide                 RWHOD(8c,C)



All fields are converted to network byte order prior to transmission.  The load
averages are as calculated 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 gethostname (see AIX Operating System Technical Reference) 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 (see AIX Operating System
Technical Reference) 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.  The rwhod
command performs an nlist (see AIX Operating System Technical Reference) on
/unix every 5 minutes to guard against the possibility that this file is not
the system image currently operating.

RELATED INFORMATION

In this book:
"rwho"
"ruptime"


























Processed October 29, 1990        RWHOD(8c,C)                                 3

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