Inetd?

[Haunter]

I understand that this is the master process that can spawn other process. I would like to know if there is a simple syntax that needs to be follow? Where can I find more readings on the subjuect.

Next, What are the pro's and con's of a standalone daemon vs one controlled by inetd?

 

[KarveR]

use xinetd its more flexible ***************************************
Party on, dudes!

 

[Haunter]

Back to the orginal question is there syntax that applies and where can I find info on it. And pro's and con's to standalone vs xinetd

 

[KarveR]

well the man pages are pretty helpful.

man xinetd :

XINETD(8) XINETD(8)

NAME
xinetd - the extended Internet services daemon

SYNOPSIS
xinetd [options]

DESCRIPTION
xinetd performs the same function as inetd: it starts pro­
grams that provide Internet services. Instead of having
such servers started at system initialization time, and be
dormant until a connection request arrives, xinetd is the
only daemon process started and it listens on all service
ports for the services listed in its configuration file.
When a request comes in, xinetd starts the appropriate
server. Because of the way it operates, xinetd (as well
as inetd) is also referred to as a super-server.

The services listed in xinetd's configuration file can be
separated into two groups. Services in the first group
are called multi-threaded and they require the forking of
a new server process for each new connection request. The
new server then handles that connection. For such ser­
vices, xinetd keeps listening for new requests so that it
can spawn new servers. On the other hand, the second
group includes services for which the service daemon is
responsible for handling all new connection requests.
Such services are called single-threaded and xinetd will
stop handling new requests for them until the server dies.
Services in this group are usually datagram-based.

So far, the only reason for the existence of a super-
server was to conserve system resources by avoiding to
fork a lot of processes which might be dormant for most of
their lifetime. While fulfilling this function, xinetd
takes advantage of the idea of a super-server to provide
features such as access control and logging. Furthermore,
xinetd is not limited to services listed in /etc/services.
Therefore, anybody can use xinetd to start special-purpose
servers.

OPTIONS
-d Enables debug mode. This produces a lot of debug­
ging output, and it makes it possible to use a
debugger on xinetd.

-syslog syslog_facility
This option enables syslog logging of xinetd-pro­
duced messages using the specified syslog facility.
The following facility names are supported: daemon,
auth, user, local[0-7] (check syslog.conf(5) for
their meanings). This option is ineffective in
debug mode since all relevant messages are sent to
the terminal.

-filelog logfile
xinetd-produced messages will be placed in the
specified file. Messages are always appended to
the file. If the file does not exist, it will be
created. This option is ineffective in debug mode
since all relevant messages are sent to the termi­
nal.

-f config_file
Determines the file that xinetd uses for configura­
tion. The default is /etc/xinetd.conf.

-pidfile pid_file
The process ID is written to the file. This option
is ineffective in debug mode.

-stayalive
Tells xinetd to stay running even if no services
are specified.

-loop rate
This option sets the loop rate beyond which a ser­
vice is considered in error and is deactivated. The
loop rate is specified in terms of the number of
servers per second that can be forked for a pro­
cess. The speed of your machine determines the
correct value for this option. The default rate is
10.

-reuse If this option is used, xinetd will set the socket
option SO_REUSEADDR before binding the service
socket to an Internet address. This allows binding
of the address even if there are programs that use
it, which happens when a previous instance of
xinetd has started some servers that are still run­
ning. This option has no effect on RPC services.

-limit proc_limit
This option places a limit on the number of concur­
rently running processes that can be started by
xinetd. Its purpose is to prevent process table
overflows.

-logprocs limit
This option places a limit on the number of concur­
rently running servers for remote userid acquisi­
tion.

-shutdownprocs limit
This option places a limit on the number of concur­
rently running servers for service shutdown (forked
when the RECORD option is used).

-cc interval
This option instructs xinetd to perform periodic
consistency checks on its internal state every
interval seconds.

The syslog and filelog options are mutually exclusive. If
none is specified, the default is syslog using the daemon
facility. You should not confuse xinetd messages with
messages related to service logging. The latter are logged
only if this is specified via the configuration file.

CONTROLLING XINETD
xinetd performs certain actions when it receives certain
signals. The actions associated with the specific signals
can be redefined by editing config.h and recompiling.

SIGUSR2 causes a hard reconfiguration, which means
that xinetd re-reads the configuration file
and terminates the servers for services
that are no longer available are. Access
control is performed again on running
servers by checking the remote location,
access times and server instances. If the
number of server instances is lowered, some
arbitrarily picked servers will be killed
to satisfy the limit; this will happen
after any servers are terminated because of
failing the remote location or access time
checks. Also, if the INTERCEPT flag was
clear and is set, any running servers for
that service will be terminated; the pur­
pose of this is to ensure that after a hard
reconfiguration there will be no running
servers that can accept packets from
addresses that do not meet the access con­
trol criteria.

SIGQUIT causes program termination.

SIGTERM terminates all running servers before ter­
minating xinetd.

SIGHUP causes an internal state dump (the default
dump file is /var/run/xinetd.dump; to
change the filename, edit config.h and
recompile).

SIGIOT causes an internal consistency check to
verify that the data structures used by the
program have not been corrupted. When the
check is completed xinetd will generate a
message that says if the check was success­
ful or not.

On reconfiguration the log files are closed and reopened.
This allows removal of old log files.

FILES
/etc/xinetd.conf default configuration file
/var/run/xinetd.dump
default dump file

SEE ALSO
inetd(8),

xinetd.conf(5),

xinetd.log(5)

AUTHOR
Panos Tsirigotis, CS Dept, University of Colorado, Boulder
Rob Braun

PRONUNCIATION
zy-net-d

14 June 2001 XINETD(8)
***************************************
Party on, dudes!