rc 脚本是 init 调用的第一个脚本，它开始引导过程。
#!/bin/bash
########################################################################
# Begin rc
#
# Description : Main Run Level Control Script
#
# Authors : Gerard Beekmans - gerard@linuxfromscratch.org
# : DJ Lucas - dj@linuxfromscratch.org
# Updates : Bruce Dubbs - bdubbs@linuxfromscratch.org
# : Pierre Labastie - pierre@linuxfromscratch.org
#
# Version : LFS 7.0
#
# Notes : Updates March 24th, 2022: new semantics of S/K files
# - Instead of testing that S scripts were K scripts in the
# previous runlevel, test that they were not S scripts
# - Instead of testing that K scripts were S scripts in the
# previous runlevel, test that they were not K scripts
# - S scripts in runlevel 0 or 6 are now run with
# "script start" (was "script stop" previously).
########################################################################
. /lib/lsb/init-functions
print_error_msg()
{
log_failure_msg
# $i is set when called
MSG="FAILURE:\n\nYou should not be reading this error message.\n\n"
MSG="${MSG}It means that an unforeseen error took place in\n"
MSG="${MSG}${i},\n"
MSG="${MSG}which exited with a return value of ${error_value}.\n"
MSG="${MSG}If you're able to track this error down to a bug in one of\n"
MSG="${MSG}the files provided by the ${DISTRO_MINI} book,\n"
MSG="${MSG}please be so kind to inform us at ${DISTRO_CONTACT}.\n"
log_failure_msg "${MSG}"
log_info_msg "Press Enter to continue..."
wait_for_user
}
check_script_status()
{
# $i is set when called
if [ ! -f ${i} ]; then
log_warning_msg "${i} is not a valid symlink."
SCRIPT_STAT="1"
fi
if [ ! -x ${i} ]; then
log_warning_msg "${i} is not executable, skipping."
SCRIPT_STAT="1"
fi
}
run()
{
if [ -z $interactive ]; then
${1} ${2}
return $?
fi
while true; do
read -p "Run ${1} ${2} (Yes/no/continue)? " -n 1 runit
echo
case ${runit} in
c | C)
interactive=""
${i} ${2}
ret=${?}
break;
;;
n | N)
return 0
;;
y | Y)
${i} ${2}
ret=${?}
break
;;
esac
done
return $ret
}
# Read any local settings/overrides
[ -r /etc/sysconfig/rc.site ] && source /etc/sysconfig/rc.site
DISTRO=${DISTRO:-"Linux From Scratch"}
DISTRO_CONTACT=${DISTRO_CONTACT:-"lfs-dev@lists.linuxfromscratch.org (Registration required)"}
DISTRO_MINI=${DISTRO_MINI:-"LFS"}
IPROMPT=${IPROMPT:-"no"}
# These 3 signals will not cause our script to exit
trap "" INT QUIT TSTP
[ "${1}" != "" ] && runlevel=${1}
if [ "${runlevel}" == "" ]; then
echo "Usage: ${0} <runlevel>" >&2
exit 1
fi
previous=${PREVLEVEL}
[ "${previous}" == "" ] && previous=N
if [ ! -d /etc/rc.d/rc${runlevel}.d ]; then
log_info_msg "/etc/rc.d/rc${runlevel}.d does not exist.\n"
exit 1
fi
if [ "$runlevel" == "6" -o "$runlevel" == "0" ]; then IPROMPT="no"; fi
# Note: In ${LOGLEVEL:-7}, it is ':' 'dash' '7', not minus 7
if [ "$runlevel" == "S" ]; then
[ -r /etc/sysconfig/console ] && source /etc/sysconfig/console
dmesg -n "${LOGLEVEL:-7}"
fi
if [ "${IPROMPT}" == "yes" -a "${runlevel}" == "S" ]; then
# The total length of the distro welcome string, without escape codes
wlen=${wlen:-$(echo "Welcome to ${DISTRO}" | wc -c )}
welcome_message=${welcome_message:-"Welcome to ${INFO}${DISTRO}${NORMAL}"}
# The total length of the interactive string, without escape codes
ilen=${ilen:-$(echo "Press 'I' to enter interactive startup" | wc -c )}
i_message=${i_message:-"Press '${FAILURE}I${NORMAL}' to enter interactive startup"}
# dcol and icol are spaces before the message to center the message
# on screen. itime is the amount of wait time for the user to press a key
wcol=$(( ( ${COLUMNS} - ${wlen} ) / 2 ))
icol=$(( ( ${COLUMNS} - ${ilen} ) / 2 ))
itime=${itime:-"3"}
echo -e "\n\n"
echo -e "\\033[${wcol}G${welcome_message}"
echo -e "\\033[${icol}G${i_message}${NORMAL}"
echo ""
read -t "${itime}" -n 1 interactive 2>&1 > /dev/null
fi
# Make lower case
[ "${interactive}" == "I" ] && interactive="i"
[ "${interactive}" != "i" ] && interactive=""
# Read the state file if it exists from runlevel S
[ -r /run/interactive ] && source /run/interactive
# Stop all services marked as K, except if marked as K in the previous
# runlevel: it is the responsibility of the script to not try to kill
# a non running service
if [ "${previous}" != "N" ]; then
for i in $(ls -v /etc/rc.d/rc${runlevel}.d/K* 2> /dev/null)
do
check_script_status
if [ "${SCRIPT_STAT}" == "1" ]; then
SCRIPT_STAT="0"
continue
fi
suffix=${i#/etc/rc.d/rc${runlevel}.d/K[0-9][0-9]}
[ -e /etc/rc.d/rc${previous}.d/K[0-9][0-9]$suffix ] && continue
run ${i} stop
error_value=${?}
if [ "${error_value}" != "0" ]; then print_error_msg; fi
done
fi
if [ "${previous}" == "N" ]; then export IN_BOOT=1; fi
if [ "$runlevel" == "6" -a -n "${FASTBOOT}" ]; then
touch /fastboot
fi
# Start all services marked as S in this runlevel, except if marked as
# S in the previous runlevel
# it is the responsibility of the script to not try to start an already running
# service
for i in $( ls -v /etc/rc.d/rc${runlevel}.d/S* 2> /dev/null)
do
if [ "${previous}" != "N" ]; then
suffix=${i#/etc/rc.d/rc${runlevel}.d/S[0-9][0-9]}
[ -e /etc/rc.d/rc${previous}.d/S[0-9][0-9]$suffix ] && continue
fi
check_script_status
if [ "${SCRIPT_STAT}" == "1" ]; then
SCRIPT_STAT="0"
continue
fi
run ${i} start
error_value=${?}
if [ "${error_value}" != "0" ]; then print_error_msg; fi
done
# Store interactive variable on switch from runlevel S and remove if not
if [ "${runlevel}" == "S" -a "${interactive}" == "i" ]; then
echo "interactive=\"i\"" > /run/interactive
else
rm -f /run/interactive 2> /dev/null
fi
# Copy the boot log on initial boot only
if [ "${previous}" == "N" -a "${runlevel}" != "S" ]; then
cat $BOOTLOG >> /var/log/boot.log
# Mark the end of boot
echo "--------" >> /var/log/boot.log
# Remove the temporary file
rm -f $BOOTLOG 2> /dev/null
fi
# End rc