175 lines
4.9 KiB
Groff
175 lines
4.9 KiB
Groff
.\" Copyright 1992, 1993 Rickard E. Faith (faith@cs.unc.edu)
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.\" May be distributed under the GNU General Public License
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.\" " for emacs's hilit19 mode :-)
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.TH SIMPLEINIT 8 "25 February 2001" "Linux 0.99" "Linux Programmer's Manual"
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.SH NAME
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simpleinit \- process control initialization
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.SH SYNOPSIS
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.B "init [ single ] [ script ]"
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.SH DESCRIPTION
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.B init
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is invoked as the last step in the Linux boot sequence. If the
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.B single
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option is used, or if the file
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.I /etc/singleboot
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exists, then single user mode will be entered, by starting
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.IR /bin/sh .
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If the file
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.I /etc/securesingle
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exists, then the root password will be required to start single user mode.
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If the root password does not exist, or if
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.I /etc/passwd
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does not exist, the checking of the password will be skipped.
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If the file
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.I /etc/TZ
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exists, then the contents of that file will be read, and used to set the TZ
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environment variable for each process started by
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.BR simpleinit .
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This "feature" is only available if it's configured at compile-time. It's
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not normally needed.
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After single user mode is terminated, the
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.I /etc/rc
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file is executed, and the information in
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.I /etc/inittab
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will be used to start processes. Alternatively, the \fI/etc/inittab\fP
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file may be configured to run a different boot script. See below for
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details.
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.SH "THE INITTAB FILE"
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Because of the number of init programs which are appearing in the Linux
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community, the documentation for the
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.I /etc/inittab
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file, which is usually found with the
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.BR inittab (5)
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man page, is presented here:
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The format is
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.RS
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.B bootprog=file
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.B fileprefix=string
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.B PATH=search path
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.B INIT_PATH=search path
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.B "ttyline:termcap-entry:getty-command"
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.B finalprog=path
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.RE
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An example is as follows:
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.nf
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.RS
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bootprog =
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fileprefix = /sbin/init.d/
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PATH = /usr/sbin:/usr/bin:/sbin:/bin
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INIT_PATH = /sbin/init.d
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tty1:linux:/sbin/getty 9600 tty1
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tty2:linux:/sbin/getty 9600 tty2
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tty3:linux:/sbin/getty 9600 tty3
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tty4:linux:/sbin/getty 9600 tty4
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# tty5:linux:/sbin/getty 9600 tty5
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# ttyS1:dumb:/sbin/getty 9600 ttyS1
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# ttyS2:dumb:/sbin/getty -m -t60 2400 ttyS2
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finalprog = /sbin/rc.xdm
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.RE
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.fi
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Lines beginning with the
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.B #
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character are treated as comments. Please see documentation for the
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.B getty (8)
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command that you are using, since there are several of these in the Linux
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community at this time.
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The \fBbootprog\fP value is appended to the \fBfileprefix\fP value,
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and the result specifies the boot programme (script) to run. If
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unspecified, the default is \fI/etc/rc\fP. If the boot programme is a
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directory, then all scripts in that directory tree are executed, in
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parallel. See the \fBneed\fP(8) programme for details on how to
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elegantly control order of execution and manage dependencies.
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The \fBPATH\fP value is assigned to the PATH environment variable of
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child processes (boot scripts).
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The \fBINIT_PATH\fP value is used by simpleinit(8) itself to find the
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location of scripts to run (if an absolute path is not given). If
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unset and the boot programme is a directory, that directory is used.
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Finally, if the script cannot be found in this path, the standard
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\fBPATH\fP is used. This separation allows boot scripts to invoke
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programmes of the same name without conflict and without needing to
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specify absolute paths.
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The \fBfinalprog\fP value specifies the path of the programme to run
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after all \fBgetty\fP(8) instances are spawned. At bootup, it is
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passed a single argument: "start". At shutdown, it is called again,
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this time with the argument: "stop".
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.SH SIGNALS
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\fBsimpleinit\fP(8) responds to signals in a variety of ways:
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.TP
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.B SIGHUP
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The \fI/etc/inittab\fP configuration file will be read again.
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.TP
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.B SIGTSTP
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This flips a toggle, which controls whether more processes will be
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spawned.
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.TP
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.B SIGINT
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\fBsimpleinit\fP(8) will sync a few times, and try to start
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\fBreboot\fP(8). Failing this, it will execute the system
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\fBreboot\fP(2) call. Under Linux, it is possible to configure the
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Ctrl-Alt-Del sequence to send a signal to the \fBinit\fP process
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instead of rebooting the system (\fBsimpleinit\fP(8) does this by
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default).
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.TP
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.B SIGQUIT
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The \fBreboot\fP(8) programme is executed in place of the
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\fBsimpleinit\fP(8) programme. This allows \fBreboot\fP(8) to cleanly
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remount (read-only) the root filesystem, even if the old inode for the
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\fBinit\fP process was unlinked.
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.SH FILES
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.I /etc/inittab
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.br
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.I /etc/singleboot
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.br
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.I /etc/securesingle
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.br
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.I /etc/TZ
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.br
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.I /etc/passwd
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.br
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.I /etc/rc
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.SH "SEE ALSO"
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.BR inittab (5),
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.BR ctrlaltdel (8)
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.BR reboot (8),
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.BR termcap (5),
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.BR getty (8),
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.BR agetty (8),
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.BR shutdown (8),
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.BR initctl (8)
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.SH BUGS
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This program is called
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.B simpleinit
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to distinguish it from the System V compatible versions of init which are
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starting to appear in the Linux community.
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.B simpleinit
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should be linked to, or made identical with,
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.I init
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for correct functionality.
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.SH AUTHOR
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Peter Orbaek (poe@daimi.aau.dk)
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.br
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Version 1.20, with patches for singleuser mode by Werner Almesberger
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.br
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Richard Gooch <rgooch@atnf.csiro.au>
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.br
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Dependency support
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