rc0(1M)          SYSTEM ADMINISTRATION COMMANDS           rc0(1M)



NAME
     rc0 - run commands performed to stop the operating system

SYNOPSIS
     /sbin/rc0

DESCRIPTION
     This file is executed at each system state change that needs
     to  have the system in an inactive state.  It is responsible
     for those actions that  bring  the  system  to  a  quiescent
     state, traditionally called ``shutdown''.

     There are three system states that require  this  procedure.
     They  are  state  0  (the  system  halt state), state 5 (the
     firmware state), and state 6 (the reboot state).  Whenever a
     change  to  one of these states occurs, the rc0 procedure is
     run.  The entry in /sbin/inittab might read:

          s0:056:wait:/sbin/rc0 >/dev/console 2>&1 </dev/console

     Some of the actions performed by  rc0  are  carried  out  by
     files  in  the  directory  /usr/sbin/shutdown.d.   and files
     beginning with K in /sbin/rc0.d.  These files  are  executed
     in  ASCII order (see FILES below for more information), ter-
     minating some system service.  The combination  of  commands
     in  rc0  and  files  in /usr/sbin/shutdown.d and /sbin/rc0.d
     determines how the system is shut down.

     The recommended sequence for rc0 is:

     Stop System Services and Daemons.

          Various system services (such as 3BNET Local Area  Net-
          work or LP Spooler) are gracefully terminated.

          When new services are added that should  be  terminated
          when the system is shut down, the appropriate files are
          installed in /usr/sbin/shutdown.d and /sbin/rc0.d.

     Terminate Processes

          SIGTERM signals are sent to all  running  processes  by
          killall(1M).  Processes stop themselves cleanly if sent
          SIGTERM.

     Kill Processes

          SIGKILL signals are sent to all remaining processes; no
          process can resist SIGKILL.

          At this point the only processes left are those associ-
          ated  with rc0 and processes 0 and 1, which are special



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rc0(1M)          SYSTEM ADMINISTRATION COMMANDS           rc0(1M)



          to the operating system.

     Unmount All File Systems

          Only the root file system (/) remains mounted.

     Depending on which system state the systems end up in (0, 5,
     or 6), the entries in /sbin/inittab will direct what happens
     next.  If  the  /sbin/inittab  has  not  defined  any  other
     actions  to  be  performed as in the case of system state 0,
     then the operating system  will  have  nothing  to  do.   It
     should  not  be possible to get the system's attention.  The
     only thing that can be done is to turn off the power or pos-
     sibly  get the attention of a firmware monitor.  The command
     can be used only by the super-user.

FILES
     The   execution   by   /usr/bin/sh   of   any    files    in
     /usr/sbin/shutdown.d  occurs  in  ASCII sort-sequence order.
     See rc2(1M) for more information.

SEE ALSO
     killall(1M), rc2(1M), shutdown(1M).
































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