INITTAB(4)INITTAB(4)NAMEinittab - script for init
DESCRIPTION
The /etc/inittab file controls process dispatching by init. The pro‐
cesses 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 Administra‐
tion 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 proper‐
ties.
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 (\) preced‐
ing a newline indicates a continuation of the entry. Up to 512 charac‐
ters for each entry are permitted. Comments may be inserted in the
process field using the convention for comments described in sh(1).
There are no limits (other than maximum entry size) imposed on the num‐
ber 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 pro‐
cesses 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 pro‐
cessed.
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 warning signal SIGTERM and allowed a
5-second grace period before being forcibly terminated by
the kill signal SIGKILL. The rstate field can define multi‐
ple 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 lev‐
els. 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 (con‐
tinue scanning the inittab file), and when the
process dies, restart the process. If the
process currently exists, do nothing and con‐
tinue scanning the inittab file.
wait
When init enters the run level that matches the
entry's rstate, start the process and wait for
its termination. All subsequent reads of the
inittab file while init is in the same run
level cause init to ignore this entry.
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 termina‐
tion; 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
continuing 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 ter‐
minating the process with the kill signal
SIGKILL. If the process is nonexistent, ignore
the entry.
ondemand
This instruction is really a synonym for the
respawn action. It is functionally identical to
respawn but is given a different keyword in
order to divorce its association with run lev‐
els. 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 console (that is, before
the Console Login: prompt). It is expected that
this entry will be used only to initialize
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 process field
is prefixed with exec and passed to a forked sh as sh −c
'exec command'. For this reason, any legal sh syntax can
appear in the process field.
SEE ALSOsh(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 provides similar functionality to
modifying the initdefault entry in previous versions of the Solaris OS.
Dec 9, 2004 INITTAB(4)
