File Formats inittab(4)
NAME
inittab - script for init
DESCRIPTION
The /etc/inittab file controls process dispatching by init.
The processes most typically dispatched by init are daemons.
It is no longer necessary to edit the /etc/inittab file
directly. Administrators should use the Solaris Service
Management Facility (SMF) to define services instead. Refer
to smf(5) and the System Administration Guide: Basic
Administration for more information on SMF.
To modify parameters passed to ttymon(1M), use svccfg(1M) to
modify the SMF repository. See ttymon(1M) for details on the
available SMF properties.
The inittab file is composed of entries that are position
dependent and have the following format:
id:rstate:action:process
Each entry is delimited by a newline; however, a backslash
(\) preceding a newline indicates a continuation of the
entry. Up to 512 characters for each entry are permitted.
Comments may be inserted in the process field using the con-
vention for comments described in sh(1). There are no limits
(other than maximum entry size) imposed on the number of
entries in the inittab file. The entry fields are:
id One to four characters used to uniquely identify
an entry. Do not use the characters "r" or "t" as
the first or only character in this field. These
characters are reserved for the use of rlogin(1)
and telnet(1).
rstate Define the run level in which this entry is to be
processed. Run-levels effectively correspond to a
configuration of processes in the system. That
is, each process spawned by init is assigned a
run level(s) in which it is allowed to exist. The
run levels are represented by a number ranging
from 0 through 6. For example, if the system is
in run level 1, only those entries having a 1 in
the rstate field are processed.
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File Formats inittab(4)
When init is requested to change run levels, all
processes that do not have an entry in the rstate
field for the target run level are sent the warn-
ing signal SIGTERM and allowed a 5-second grace
period before being forcibly terminated by the
kill signal SIGKIL. The rstate field can define
multiple run levels for a process by selecting
more than one run level in any combination from 0
through 6. If no run level is specified, then the
process is assumed to be valid at all run levels
0 through 6.
There are three other values, a, b and c, which
can appear in the rstate field, even though they
are not true run levels. Entries which have these
characters in the rstate field are processed only
when an init or telinit process requests them to
be run (regardless of the current run level of
the system). See init(1M). These differ from run
levels in that init can never enter run level a,
b or c. Also, a request for the execution of any
of these processes does not change the current
run level. Furthermore, a process started by an
a, b or c command is not killed when init changes
levels. They are killed only if their line in
inittab is marked off in the action field, their
line is deleted entirely from inittab, or init
goes into single-user state.
action Key words in this field tell init how to treat
the process specified in the process field. The
actions recognized by init are as follows:
respawn If the process does not exist, then
start the process; do not wait for
its termination (continue scanning
the inittab file), and when the pro-
cess dies, restart the process. If
the process currently exists, do
nothing and continue scanning the
inittab file.
wait When init enters the run level that
matches the entry's rstate, start
the process and wait for its termi-
nation. All subsequent reads of the
inittab file while init is in the
same run level cause init to ignore
this entry.
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File Formats inittab(4)
once When init enters a run level that
matches the entry's rstate, start
the process, do not wait for its
termination. When it dies, do not
restart the process. If init enters
a new run level and the process is
still running from a previous run
level change, the program is not
restarted.
boot The entry is to be processed only at
init's boot-time read of the inittab
file. init is to start the process
and not wait for its termination;
when it dies, it does not restart
the process. In order for this
instruction to be meaningful, the
rstate should be the default or it
must match init's run level at boot
time. This action is useful for an
initialization function following a
hardware reboot of the system.
bootwait The entry is to be processed the
first time init goes from single-
user to multi-user state after the
system is booted. init starts the
process, waits for its termination
and, when it dies, does not restart
the process.
powerfail Execute the process associated with
this entry only when init receives a
power fail signal, SIGPWR (see
signal(3C)).
powerwait Execute the process associated with
this entry only when init receives a
power fail signal, SIGPWR, and wait
until it terminates before continu-
ing any processing of inittab.
off If the process associated with this
entry is currently running, send the
warning signal SIGTERM and wait 5
seconds before forcibly terminating
the process with the kill signal
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File Formats inittab(4)
SIGKIL. If the process is nonex-
istent, ignore the entry.
ondemand This instruction is really a synonym
for the respawn action. It is func-
tionally identical to respawn but is
given a different keyword in order
to divorce its association with run
levels. This instruction is used
only with the a, b or c values
described in the rstate field.
sysinit Entries of this type are executed
before init tries to access the con-
sole (that is, before the Console
Login: prompt). It is expected that
this entry will be used only to ini-
tialize devices that init might try
to ask the run level question. These
entries are executed and init waits
for their completion before continu-
ing.
process Specify a command to be executed. The entire pro-
cess field is prefixed with exec and passed to a
forked sh as sh -c 'exec command'. For this rea-
son, any legal sh syntax can appear in the pro-
cess field.
SEE ALSO
sh(1), who(1), init(1M), svcadm(1M), svc.startd(1M),
ttymon(1M), exec(2), open(2), signal(3C), smf(5)
System Administration Guide: Basic Administration
NOTES
With the introduction of the service management facility,
the system-provided /etc/inittab file is greatly reduced
from previous releases.
The initdefault entry is not recognized in Solaris 10. See
smf(5) for information on SMF milestones, and svcadm(1M),
which describes the "svcadm milestone -d" command; this pro-
vides similar functionality to modifying the initdefault
entry in previous versions of the Solaris OS.
SunOS 5.11 Last change: 9 Dec 2004 4
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