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diff --git a/chapter07/rc.sgml b/chapter07/rc.sgml new file mode 100644 index 000000000..3aba51da3 --- /dev/null +++ b/chapter07/rc.sgml @@ -0,0 +1,253 @@ +<sect1 id="ch07-rc"> +<title>Creating the rc script</title> + +<para> +The first main bootscript is the <filename>/etc/init.d/rc</filename> script. +Create a new file <filename>/etc/init.d/rc</filename> containing the +following: </para> + +<literallayout> + +<userinput>cat > rc << "EOF"</userinput> +#!/bin/sh +# Begin /etc/init.d/rc +# +# By Jason Pearce - jason.pearce@linux.org +# Modified by Gerard Beekmans - gerard@linuxfromscratch.org +# print_error_msg based on ideas by Simon Perreault - nomis80@yahoo.com + +# +# Include the functions declared in the /etc/init.d/functions file +# + +source /etc/init.d/functions + +# +# The print_error_msg function prints an error message when an unforseen +# error occured that wasn't trapped for some reason by a evaluate_retval +# call or error checking in different ways. + +print_error_msg() +{ + + echo + $FAILURE + echo -n "You should not read this error message. It means " + echo "that an unforseen error " + echo -n "took place and subscript $i exited with " + echo "a return value " + echo -n "of $error_value for an unknown reason. If you're able " + echo "to trace this error down " + echo -n "to a bug in one of the files provided by this book, " + echo "please be so kind to " + echo -n "inform us at lfs-discuss@linuxfromscratch.org" + $NORMAL + echo + echo + echo "Press a key to continue..." + read +} + +# +# If you uncomment the debug variable below none of the scripts will be +# executed, just the script name and parameters will be echo'ed to the +# screen so you can see how the scripts are called by rc. +# + +# Un-comment the following for debugging. +# debug=echo + +# +# Start script or program. +# +startup() { + +$debug $* + +} + +# +# Ignore CTRL-C only in this shell, so we can interrupt subprocesses. +# + +trap ":" INT QUIT TSTP + +# +# Now find out what the current and what the previous runlevel are. The +# $RUNLEVEL variable is set by init for all it's children. This script +# runs as a child of init. +# + +runlevel=$RUNLEVEL + +# +# Get first argument. Set new runlevel to this argument. If no runlevel +# was passed to this script we won't change runlevels. +# + +[ "$1" != "" ] && runlevel=$1 +if [ "$runlevel" = "" ] +then + echo "Usage: $0 <runlevel>" >&2 + exit 1 +fi + +# +# The same goes for $PREVLEVEL (see above for $RUNLEVEL). previous will +# be set to the previous run level. If $PREVLEVEL is not set it means +# that there is no previous runlevel and we'll set previous to N. +# + +previous=$PREVLEVEL +[ "$previous" = "" ] && previous=N + +export runlevel previous + +# +# Is there an rc directory for the new runlevel? +# + +if [ -d /etc/rc$runlevel.d ] + +then + +# +# If so, first collect all the K* scripts in the new run level. +# + + if [ $previous != N ] + then + for i in /etc/rc$runlevel.d/K* + do + [ ! -f $i ] && continue + +# +# the suffix variable will contain the script name without the leading +# Kxxx +# + + suffix=${i#/etc/rc$runlevel.d/K[0-9][0-9][0-9]} +# +# If there is a start script for this K script in the previous runlevel +# determine what it's full path is +# + previous_start=/etc/rc$previous.d/S[0-9][0-9][0-9]$suffix +# +# If there was no previous run level it could be that something was +# started in rcS.d (sysinit level) so we'll determine the path for that +# possibility as well. +# + + sysinit_start=/etc/rcS.d/S[0-9][0-9][0-9]$suffix + +# +# Stop the service if there is a start script in the previous run level +# or in the sysinit level. If previous_start or sysinit_start do not +# exist the 'continue' command is run which causes the script to abort +# this iteration of the for loop and continue with the next iteration. +# This boils down to that it won't run the commands after the next two +# lines and start over from the top of this for loop. See man bash for +# more info on this. +# + + [ ! -f $previous_start ] && + [ ! -f $sysinit_start ] && continue + +# +# If we found previous_start or sysinit_start, run the K script +# + + startup $i stop + error_value=$? +# +# If the return value of the script is not 0, something went wrong with +# error checking inside the script. the print_error_msg function will be +# called and the message plus the return value of the K script will be +# printed to the screen + +# + + if [ $error_value != 0 ] + then + print_error_msg + fi + + done + fi + +# +# Now run the START scripts for this runlevel. +# + + for i in /etc/rc$runlevel.d/S* + do + [ ! -f $i ] && continue + + if [ $previous != N ] + then +# +# Find start script in previous runlevel and stop script in this +# runlevel. +# + + suffix=${i#/etc/rc$runlevel.d/S[0-9][0-9][0-9]} + stop=/etc/rc$runlevel.d/K[0-9][0-9][0-9]$suffix + previous_start=/etc/rc$previous.d/S[0-9][0-9][0-9]$suffix +# +# If there is a start script in the previous level and no stop script in +# this level, we don't have to re-start the service; abort this +# iteration and start the next one. +# + + [ -f $previous_start ] && [ ! -f $stop ] && + continue + fi + + case "$runlevel" in + 0|6) + +# +# levels 0 and 6 are halt and reboot levels. We don't really start +# anything here so we call with the 'stop' parameter +# + + startup $i stop + error_value=$? +# +# If the return value of the script is not 0, something went wrong with +# error checking inside the script. the print_error_msg function will be +# called and the message plus the return value of the K script will be +# printed to the screen +# + + if [ $error_value != 0 ] + then + print_error_msg + fi + ;; + *) + startup $i start + error_value=$? +# +# If the return value of the script is not 0, something went wrong with +# error checking inside the script. the print_error_msg function will be +# called and the message plus the return value of the K script will be +# printed to the screen +# + + if [ $error_value != 0 ] + then + print_error_msg + fi + ;; + esac + done +fi + +# End /etc/init.d/rc +<userinput>EOF</userinput> + +</literallayout> + +</sect1> + |