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init(1M)							      init(1M)

NAME
       init, telinit - process control initialization

SYNOPSIS
       /sbin/init [0123456abcQqSs]

       /etc/telinit [0123456abcQqSs]

       init is the default primordial user process. (Options given to the ker-
       nel during boot may result in the invocation of an alternative  primor-
       dial user process, as described on kernel(1M)). init initiates the core
       components of the  service  management  facility,  svc.configd(1M)  and
       svc.startd(1M),	and  restarts these components if they fail. For back-
       wards compatibility, init also starts and  restarts  general  processes
       according to /etc/inittab, as desribed below.

       The run levels and system booting descriptions given below are provided
       for compatibility purposes only,	and otherwise  made  obsolete  by  the
       service management facility, smf(5).

   init	Failure
       If  init	 exits	for  any reason	other than system shutdown, it will be
       restarted with process-ID 1.

   Run Level Defined
       At any given time, the system is	in one of eight	possible run levels. A
       run level is a software configuration under which only a	selected group
       of processes exists. Processes spawned by init for each	of  these  run
       levels  are  defined  in	 /etc/inittab. init can	be in one of eight run
       levels, 0-6 and S or s (S and s are identical). The run	level  changes
       when a privileged user runs /sbin/init.

   init	and System Booting
       When  the  system  is booted, init is invoked and the following occurs.
       First, it reads /etc/default/init to set	environment variables. This is
       typically  where	TZ (time zone) and locale-related environments such as
       LANG or LC_CTYPE	get set. (See the FILES	section	at  the	 end  of  this
       page.)  init  then looks	in /etc/inittab	for the	initdefault entry (see
       inittab(4)). If the initdefault entry:

       exists		       init usually uses the run  level	 specified  in
			       that  entry  as	the initial run	level to enter
			       only if the options/milestone property has  not
			       been specified for svc.startd(1M).

       does not	exist	       The  service management facility, smf(5), exam-
			       ines    its    configuration    specified    in
			       svc.startd(1M), and enters the milestone	speci-
			       fied by the options/milestone property.

       The initdefault entry in	/etc/inittab corresponds to the	following  run
       levels:

       S or s		       init  goes  to  the  single-user	state. In this
			       state, the system console device	(/dev/console)
			       is  opened for reading and writing and the com-
			       mand /sbin/su, (see su(1M)),  is	 invoked.  Use
			       either  init or telinit to change the run level
			       of the system. Note that	if the shell is	termi-
			       nated (using an end-of-file), init only re-ini-
			       tializes	to the single-user state if /etc/init-
			       tab does	not exist.

       0-6		       init  enters  the  corresponding	run level. Run
			       levels 0, 5, and	 6  are	 reserved  states  for
			       shutting	 the system down. Run levels 2,	3, and
			       4 are available as multi-user operating states.

       If this is the first time since power up	that init has  entered	a  run
       level  other  than single-user state, init first	scans /etc/inittab for
       boot and	bootwait entries (see inittab(4)). These entries are performed
       before any other	processing of /etc/inittab takes place,	providing that
       the run level entered matches that of the entry.	In this	way  any  spe-
       cial initialization of the operating system, such as mounting file sys-
       tems, can take place before users are allowed  onto  the	 system.  init
       then  scans  /etc/inittab and executes all other	entries	that are to be
       processed for that run level.

       To spawn	each process in	/etc/inittab, init reads each  entry  and  for
       each entry that should be respawned, it forks a child process. After it
       has spawned all of the processes	specified by /etc/inittab, init	 waits
       for  one	 of  its descendant processes to die, a	powerfail signal, or a
       signal from another init	or telinit process to change the system's  run
       level. When one of these	conditions occurs, init	re-examines /etc/init-
       tab.

   inittab Additions
       New entries can be added	to /etc/inittab	at  any	 time;	however,  init
       still  waits  for one of	the above three	conditions to occur before re-
       examining /etc/inittab. To get around this, init	Q or  init  q  command
       wakes init to re-examine	/etc/inittab immediately.

       When  init  comes  up at	boot time and whenever the system changes from
       the single-user state to	another	run  state,  init  sets	 the  ioctl(2)
       states	of   the   console   to	  those	  modes	  saved	 in  the  file
       /etc/ioctl.syscon. init writes this file	whenever the single-user state
       is entered.

   Run Level Changes
       When  a run level change	request	is made, init or a designate sends the
       warning signal (SIGTERM)	to all processes that  are  undefined  in  the
       target run level. A minimum interval of five seconds is observed	before
       init or its designate forcibly terminates these processes by sending  a
       kill signal (SIGKILL).

       When  init  receives  a signal telling it that a	process	it spawned has
       died, it	records	the fact and the reason	it died	in /var/adm/utmpx  and
       /var/adm/wtmpx  if  it  exists (see who(1)). A history of the processes
       spawned is kept in /var/adm/wtmpx.

       If init receives	a powerfail signal (SIGPWR) it scans /etc/inittab  for
       special	entries	of the type powerfail and powerwait. These entries are
       invoked (if the run levels permit) before any further processing	 takes
       place. In this way init can perform various cleanup and recording func-
       tions during the	powerdown of the operating system.

   Environment Variables in /etc/default/init
       You can set default values for environment variables, for such items as
       timezone	 and character formatting, in /etc/default/init. See the FILES
       section,	below, for a list of these variables.

   telinit
       telinit,	which is linked	to /sbin/init, is used to direct  the  actions
       of init.	It takes a one-character argument and signals init to take the
       appropriate action.

SECURITY
       init uses pam(3PAM) for session management. The PAM configuration  pol-
       icy,  listed  through  /etc/pam.conf,  specifies	the session management
       module to be used for init. Here	is a partial pam.conf  file  with  en-
       tries for init using the	UNIX session management	module.

       init   session	required    pam_unix_session.so.1

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

       0	       Go into firmware.

       1	       Put the system in system	administrator mode. All	 local
		       file systems are	mounted. Only a	small set of essential
		       kernel processes	are left running. This mode is for ad-
		       ministrative  tasks such	as installing optional utility
		       packages. All files are accessible  and	no  users  are
		       logged in on the	system.

		       This request corresponds	to a request for smf(5)	to re-
		       strict the system milestone  to	svc:/milestone/single-
		       user:default.

       2	       Put the system in multi-user mode. All multi-user envi-
		       ronment terminal	processes  and	daemons	 are  spawned.
		       This  state  is	commonly referred to as	the multi-user
		       state.

		       This request corresponds	to a request for smf(5)	to re-
		       strict  the  system  milestone to svc:/milestone/multi-
		       user:default.

       3	       Extend multi-user mode by making	local resources	avail-
		       able over the network.

		       This request corresponds	to a request for smf(5)	to re-
		       strict the system  milestone  to	 svc:/milestone/multi-
		       user-server:default.

       4	       Is available to be defined as an	alternative multi-user
		       environment configuration. It is	not necessary for sys-
		       tem operation and is usually not	used.

       5	       Shut  the machine down so that it is safe to remove the
		       power. Have the machine remove power, if	possible.

       6	       Stop the	operating system and reboot to the  state  de-
		       fined by	the initdefault	entry in /etc/inittab.

       a,b,c	       Process	only  those /etc/inittab entries having	the a,
		       b, or c run level set. These are	 pseudo-states,	 which
		       may  be	defined	 to run	certain	commands, but which do
		       not cause the current run level to change.

       Q,q	       Re-examine /etc/inittab.

       S, s	       Enter single-user mode. This is the only	run level that
		       doesn't	require	 the existence of a properly formatted
		       /etc/inittab file. If this file does not	exist, then by
		       default,	 the  only legal run level that	init can enter
		       is the single-user mode.	When in	single-user mode,  the
		       filesystems required for	basic system operation will be
		       mounted.	When the  system  comes	 down  to  single-user
		       mode,  these  file systems will remain mounted (even if
		       provided	by a remote file server), and any other	 local
		       filesystems will	also be	left mounted. During the tran-
		       sition down to single-user mode,	all processes  started
		       by  init	 or init.d scripts that	should only be running
		       in multi-user mode are killed. In addition, any process
		       that has	a utmpx	entry will be killed. This last	condi-
		       tion insures that all port monitors started by the  SAC
		       are killed and all services started by these port moni-
		       tors, including ttymon login services, are killed.

       /dev/console	       System console device

       /etc/default/init       Contains	environment variables  and  their  de-
			       fault  values.  For  example,  for the timezone
			       variable, TZ, you might specify	TZ=US/Pacific.
			       The variables are:

			       TZ	       Either  specifies  the timezone
					       information (see	ctime(3C))  or
					       the name	of a timezone informa-
					       tion file  /usr/share/lib/zone-
					       info.

					       Refer  to  the  TIMEZONE(4) man
					       page before changing this  set-
					       ting.

			       CMASK	       The  mask  (see	umask(1)) that
					       init  uses   and	  that	 every
					       process	inherits from the init
					       process.	If not set, init  uses
					       the  mask  it inherits from the
					       kernel. Note that  init	always
					       attempts	 to  apply  a umask of
					       022 before creating a file, re-
					       gardless	  of  the  setting  of
					       CMASK

			       LC_CTYPE	       Character characterization  in-
					       formation

			       LC_MESSAGES     Message translation

			       LC_MONETARY     Monetary	formatting information

			       LC_NUMERIC      Numeric formatting information

			       LC_TIME	       Time formatting information

			       LC_ALL	       If set, all other LC_* environ-
					       mental variables	 take-on  this
					       value.

			       LANG	       If  LC_ALL  is not set, and any
					       particular  LC_*	 is  also  not
					       set,  the value of LANG is used
					       for that	particular environmen-
					       tal variable.

       /etc/initpipe	       A named pipe used for internal communication

       /etc/inittab	       Controls	process	dispatching by init

       /etc/ioctl.syscon       ioctl  states  of the console, as saved by init
			       when single-user	state is entered

       /var/adm/utmpx	       User access and administration information

       /var/adm/wtmpx	       History of user access and  administration  in-
			       formation

       /var/run/init.state     init state necessary to recover from failure.

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE	TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWcsu			   |
       +-----------------------------+-----------------------------+

       login(1),  sh(1),  stty(1),  who(1),  kernel(1M), shutdown(1M), su(1M),
       svc.configd(1M),	  svc.startd(1M),   ttymon(1M),	  ioctl(2),   kill(2),
       ctime(3C),  pam(3PAM), init.d(4), inittab(4), pam.conf(4), TIMEZONE(4),
       utmpx(4),  attributes(5),   pam_authtok_check(5),   pam_authtok_get(5),
       pam_authtok_store(5),  pam_dhkeys(5),  pam_passwd_auth(5), pam_unix_ac-
       count(5), pam_unix_auth(5), pam_unix_session(5),	smf(5),	termio(7I)

DIAGNOSTICS
       If init finds that it is	respawning an  entry  from  /etc/inittab  more
       than  ten  times	 in two	minutes, assumes that there is an error	in the
       command string in the entry, and	generates an error message on the sys-
       tem  console.  It  will	then refuse to respawn this entry until	either
       five minutes has	elapsed	or it receives a signal	 from  a  user-spawned
       init  or	 telinit.  This	 prevents init from eating up system resources
       when someone makes a typographical error	in the inittab file, or	a pro-
       gram is removed that is referenced in /etc/inittab.

       init and	telinit	can be run only	by a privileged	user.

       The  S  or  s  state must not be	used indiscriminately in /etc/inittab.
       When modifying this file, it is best to avoid adding this state to  any
       line other than initdefault.

       If  a  default  state  is  not  specified  in  the initdefault entry in
       /etc/inittab, state 6 is	entered. Consequently, the system will loop by
       going to	firmware and rebooting continuously.

       If the utmpx file cannot	be created when	booting	the system, the	system
       will boot to state "s" regardless of the	state specified	in the initde-
       fault  entry in /etc/inittab. This can occur if the /var	file system is
       not accessible.

       When a system transitions down to the S or s  state,  the  /etc/nologin
       file  (see  nologin(4))	is created.  Upon subsequent transition	to run
       level 2,	this file is removed.

       init uses /etc/initpipe,	a named	pipe, for internal communication.

       The pam_unix(5) module is no longer supported. Similar functionality is
       provided	  by   pam_authtok_check(5),   pam_authtok_get(5),   pam_auth-
       tok_store(5), pam_dhkeys(5),  pam_passwd_auth(5),  pam_unix_account(5),
       pam_unix_auth(5), and pam_unix_session(5).

				  17 Aug 2005			      init(1M)

NAME | SYNOPSIS | SECURITY | DIAGNOSTICS

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