INITTAB(5) Standards, Environments, and Macros INITTAB(5)


inittab - script for init


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(7) and the System Administration
Guide: Basic Administration for more information on SMF.

To modify parameters passed to ttymon(8), use svccfg(8) to modify the SMF
repository. See ttymon(8) for details on the available SMF properties.

The inittab file is composed of entries that are position dependent and
have the following format:


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 convention 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:

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).

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.

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 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(8). 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.

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:

If the process does not exist, then start the
process; do not wait for its termination
(continue scanning the inittab file), and when
the process dies, restart the process. If the
process currently exists, do nothing and continue
scanning the inittab file.

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.

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.

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.

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.

Execute the process associated with this entry
only when init receives a power fail signal,
SIGPWR (see signal(3C)).

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.

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
SIGKILL. If the process is nonexistent, ignore
the entry.

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 levels. This
instruction is used only with the a, b or c
values described in the rstate field.

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 continuing.

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.


sh(1), who(1), exec(2), open(2), signal(3C), smf(7), init(8),
svc.startd(8), svcadm(8), ttymon(8)

System Administration Guide: Basic Administration


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(7) for
information on SMF milestones, and svcadm(8), which describes the "svcadm
milestone -d" command; this provides similar functionality to modifying
the initdefault entry in previous versions of the Solaris OS.

December 9, 2004 INITTAB(5)