sac(1M)								       sac(1M)

NAME    [Toc]    [Back]

     sac - service access controller

SYNOPSIS    [Toc]    [Back]

     sac -t sanity_interval

DESCRIPTION    [Toc]    [Back]

     The Service Access	Controller (SAC) is the	overseer of the	server
     machine.  It is started when the server machine enters multiuser mode.
     The SAC performs several important	functions as explained below.

     Customizing the SAC environment.  When sac	is invoked, it first looks for
     the per-system configuration script /etc/saf/_sysconfig.  sac interprets
     _sysconfig	to customize its own environment.  The modifications made to
     the SAC environment by _sysconfig are inherited by	all the	children of
     the SAC.  This inherited environment may be modified by the children.

     Starting port monitors.  After it has interpreted the _sysconfig file,
     the sac reads its administrative file /etc/saf/_sactab.  _sactab
     specifies which port monitors are to be started.  For each	port monitor
     to	be started, sac	forks a	child and creates a utmp entry with the	type
     field set to LOGIN_PROCESS.  Each child then interprets its per-port
     monitor configuration script /etc/saf/pmtag<b>/_config, if the file exists.
     These modifications to the	environment affect the port monitor and	will
     be	inherited by all its children.	Finally, the child process execs the
     port monitor, using the command found in the _sactab entry.

     Polling port monitors to detect failure.  The -t option sets the
     frequency with which sac polls the	port monitors on the system.  This
     time may also be thought of as half of the	maximum	latency	required to
     detect that a port	monitor	has failed and that recovery action is
     necessary.

     Administrative functions.	The Service Access Controller represents the
     administrative point of control for port monitors.	 Its administrative
     tasks are explained below.

     A port monitor may	be in one of six states:

     ENABLED   The port	monitor	is currently running and is accepting
	       connections.

     DISABLED  The port	monitor	is currently running and is not	accepting
	       connections.

     STARTING  The port	monitor	is in the process of starting up.  STARTING is
	       an intermediate state on	the way	to ENABLED or DISABLED.

     FAILED    The port	monitor	was unable to start and	remain running.






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sac(1M)								       sac(1M)



     STOPPING  The port	monitor	has been manually terminated but has not
	       completed its shutdown procedure.  STOPPING is an intermediate
	       state on	the way	to NOTRUNNING.

     NOTRUNNING
	       The port	monitor	is not currently running.  This	is the normal
	       ``not running'' state.  When a port monitor is killed, all
	       ports it	was monitoring are inaccessible.  It is	not possible
	       for an external user to tell whether a port is not being
	       monitored or the	system is down.	 If the	port monitor is	not
	       killed but is in	the DISABLED state, it may be possible
	       (depending on the port monitor being used) to write a message
	       on the inaccessible port	telling	the user who is	trying to
	       access the port that it is disabled.  This is the advantage of
	       having a	DISABLED state as well as the NOTRUNNING state.

     When a port monitor terminates, the SAC frees the utmp entry for that
     port monitor.

     The SAC receives all requests to enable, disable, start, or stop port
     monitors and takes	the appropriate	action.

     The SAC is	responsible for	restarting port	monitors that terminate.
     Whether or	not the	SAC will restart a given port monitor depends on two
     things:


	  -  the restart count specified for the port monitor when the port
	     monitor was added.

	  -  the number	of times the port monitor has already been restarted

FILES    [Toc]    [Back]

     /etc/saf/_sactab
     /etc/saf/_sysconfig
     /var/adm/utmp
     /var/saf/_log


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