Maintenance Commands                                      sac(1M)

NAME
     sac - service access controller

SYNOPSIS
     sac -t sanity_interval

     /usr/lib/saf/sac

DESCRIPTION
     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  con-
     figuration  script /etc/saf/_sysconfig. sac interprets _sys-
     config 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 (see fork(2)) and creates a
     utmpx entry with the type field set to  LOGIN_PROCESS.  Each
     child  then  interprets  its  per-port monitor configuration
     script /etc/saf/pmtag/_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.  (See sacadm; this is  the  com-
     mand given with the -c option when the port monitor is added
     to the system.)

  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 neces-
     sary.

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

     When queried (sacadm with either  -l  or  -L),  the  Service
     Access Controller returns the status
      of the port monitors specified, which sacadm prints on  the

SunOS 5.8           Last change: 11 Nov 1998                    1

Maintenance Commands                                      sac(1M)

     standard output. A port monitor may be in one of six states:

     ENABLED
           The port monitor is currently running and is accepting
           connections. See sacadm(1M) with the -e option.

     DISABLED
           The port monitor  is  currently  running  and  is  not
           accepting  connections. See sacadm with the -d option,
           and see NOTRUNNING, below.

     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  run-
           ning.

     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. (See sacadm
           with -k.) 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  removes  the  utmpx
     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:

        o  The restart count specified for the port monitor  when
           the port monitor was added by sacadm; this information
           is included in /etc/saf/pmtag/_sactab.

SunOS 5.8           Last change: 11 Nov 1998                    2

Maintenance Commands                                      sac(1M)

        o  The number of times the port monitor has already  been
           restarted.

SECURITY
     sac uses pam(3PAM) for session management.  The  PAM  confi-
     guration policy, listed through /etc/pam.conf, specifies the
     session management module to be used for sac. Here is a par-
     tial  pam.conf file with entries for sac using the UNIX ses-
     sion management module.

     sac  session   required   /usr/lib/security/pam_unix.so.1

     If there are no  entries  for  the  sac  service,  then  the
     entries for the "other" service will be used.

OPTIONS
     -t sanity_interval
           Sets the frequency (sanity_interval)  with  which  sac
           polls the port monitors on the system.

FILES
     /etc/saf/_sactab

     /etc/saf/_sysconfig

     /var/adm/utmpx

     /var/saf/_log

ATTRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:

     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Availability                | SUNWcsu                     |
    |_____________________________|_____________________________|

SEE ALSO
     pmadm(1M),  sacadm(1M),  fork(2)   pam(3PAM),   pam.conf(4),
     attributes(5), pam_unix(5)

SunOS 5.8           Last change: 11 Nov 1998                    3