lfs-book-zh_CN/bootscripts/lfs/init.d/rc

#!/bin/bash
########################################################################
# Begin rc
#
# 描述        : 主要运行级别控制脚本
#
# 作者        : Gerard Beekmans  - gerard@linuxfromscratch.org
#             : DJ Lucas - dj@linuxfromscratch.org
# 更新者      : Bruce Dubbs - bdubbs@linuxfromscratch.org
#
# 版本        : LFS 7.0
#
########################################################################

. /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
}

# 读入所有本地设置和覆盖选项
[ -r /etc/sysconfig/rc.site ] && source /etc/sysconfig/rc.site

DISTRO=${DISTRO:-"Linux From Scratch"}
DISTRO_CONTACT=${DISTRO_CONTACT:-"lfs-dev@linuxfromscratch.org (Registration required)"}
DISTRO_MINI=${DISTRO_MINI:-"LFS"}
IPROMPT=${IPROMPT:-"no"}

# 这三个信号不会使得该脚本退出
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

# 注意: ${LOGLEVEL:-7} 中, ':-7' 应读作 '冒号' '杠' '七', 不是负七。
if [ "$runlevel" == "S" ]; then 
   [ -r /etc/sysconfig/console ] && source /etc/sysconfig/console 
   dmesg -n "${LOGLEVEL:-7}" 
fi

if [ "${IPROMPT}" == "yes" -a "${runlevel}" == "S" ]; then
   # 发行版欢迎消息字符串的总长度，不计转义代码
   wlen=${wlen:-$(echo "Welcome to ${DISTRO}" | wc -c )}
   welcome_message=${welcome_message:-"Welcome to ${INFO}${DISTRO}${NORMAL}"}

   # 交互字符串的总长度，不计转义代码
   ilen=${ilen:-$(echo "Press 'I' to enter interactive startup" | wc -c )}
   i_message=${i_message:-"Press '${FAILURE}I${NORMAL}' to enter interactive startup"}


   # dcol 和 icol 是消息前应有的空格数，这些空格使得消息居中。
   # itime 是等待用户输入按键的时间。
   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

# 将用户输入变成小写
[ "${interactive}" == "I" ] && interactive="i"
[ "${interactive}" != "i" ] && interactive=""

# 如果是从运行级别 S 切换而来，读入状态文件
[ -r /var/run/interactive ] && source /var/run/interactive

# 试图停止那些在上一运行级别启动，而在该运行级别中禁用的服务
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]}
      prev_start=/etc/rc.d/rc$previous.d/S[0-9][0-9]$suffix
      sysinit_start=/etc/rc.d/rcS.d/S[0-9][0-9]$suffix

      if [ "${runlevel}" != "0" -a "${runlevel}" != "6" ]; then
         if [ ! -f ${prev_start} -a  ! -f ${sysinit_start} ]; then
            MSG="WARNING:\n\n${i} can't be "
            MSG="${MSG}executed because it was not "
            MSG="${MSG}not started in the previous "
            MSG="${MSG}runlevel (${previous})."
            log_warning_msg "$MSG"
            continue
         fi
      fi

      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


# 启动该运行级别启用的所有服务
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$runlevel.d/S[0-9][0-9]}
      stop=/etc/rc.d/rc$runlevel.d/K[0-9][0-9]$suffix
      prev_start=/etc/rc.d/rc$previous.d/S[0-9][0-9]$suffix

      [ -f ${prev_start} -a ! -f ${stop} ] && continue
   fi

   check_script_status
      if [ "${SCRIPT_STAT}" == "1" ]; then
         SCRIPT_STAT="0"
         continue
      fi

   case ${runlevel} in
      0|6)
         run ${i} stop
         ;;
      *)
         run ${i} start
         ;;
   esac

   error_value=${?}

   if [ "${error_value}" != "0" ]; then print_error_msg; fi
done

# 对于运行级别 S，保存交互状态，否则删除状态文件
if [ "${runlevel}" == "S" -a "${interactive}" == "i" ]; then
    echo "interactive=\"i\"" > /var/run/interactive
else
    rm -f /var/run/interactive 2> /dev/null
fi

# 仅为初次引导复制引导日志
if [ "${previous}" == "N" -a  "${runlevel}" != "S" ]; then
   cat $BOOTLOG >> /var/log/boot.log
      
   # 标记引导结束
   echo "--------" >> /var/log/boot.log
   
   # 删除临时文件
   rm -f $BOOTLOG 2> /dev/null
fi

# End rc