HP-UX Reference (11i v1 05/09) - 1M System Administration Commands A-M (vol 3)

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init(1M) init(1M)

When boot init is requested to change run levels via a user

init, it sends the warning signal SIGTERM

to all processes that are undeﬁned in the target run level. Boot

init waits 20 seconds before forcibly ter-

minating these processes with the kill signal

SIGKILL

. Note that boot init assumes that all these

processes (and their descendants) remain in the same process group that boot

init originally created for

them. If any process changes its process group afﬁliation with either

setpgrp() or setpgrp2() (see

setsid(2) and setpgid(2)), it will not receive these signals. (Common examples of such processes are the

shells

csh and ksh (see csh(1) and ksh(1).) Such processes need to be terminated separately.

A user

init can be invoked only by users with appropriate privileges.

SECURITY FEATURES

Boot Authentication

If the bundle BOOTAUTH11i is installed, the system administrator can enable the boot authentication

feature. If enabled, the system cannot be booted into single user mode until the password of a user author-

ized to boot the system in single user mode is provided. Refer to the

/etc/default/security

ﬁle in

the security(4) manual page for detailed information on conﬁgurable parameters that affect the behavior of

this command. The currently supported parameters for boot authentication are:

BOOT_AUTH

On systems that have been converted to trusted mode, use the System Administration Manager (SAM) pro-

gram (see sam(1M)).

DIAGNOSTICS

If boot init ﬁnds that it is continuously respawning an entry from inittab more than 10 times in 2

minutes, it will assume that there is an error in the command string, generate an error message on the sys-

tem console, and refuse to respawn this entry until either 5 minutes have elapsed or it receives a signal

from a user init. This prevents boot init from using up system resources if there is a typographical

error in the inittab ﬁle or a program is removed that is referenced in inittab

WARNINGS

Boot

init assumes that processes and descendants of processes spawned by boot init remain in the

same process group that boot init originally created for them. When changing init states, special care

should be taken with processes that change their process group afﬁliation, such as csh

and ksh.

One particular scenario that often causes confusing behavior can occur when a child

csh or ksh is started

by a login shell. When boot

init is asked to change to a run level that would cause the original login shell

to be killed, the shell’s descendant csh or ksh process does not receive a hangup signal since it has

changed its process group afﬁliation and is no longer afﬁliated with the process group of the original shell.

Boot init cannot kill this csh or ksh process (or any of its children).

If a getty process is later started on the same tty as this previous shell, the result may be two processes

(the getty and the job control shell) competing for input on the tty.

To avoid problems such as this, always be sure to manually kill any job control shells that should not be

running after changing init states. Also, always be sure that user init is invoked from the lowest level

(login) shell when changing to an init state that may cause your login shell to be killed.

FILES

/dev/syscon

/dev/systty

/etc/default/security

/etc/inittab

/etc/ioctl.syscon

/etc/utmp

/var/adm/wtmp