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