#!/bin/sh

#

# rc     This file is responsible for starting/stopping

#        services when the runlevel changes.

#

#        Optimization feature:

#        A startup script is _not_ run when the service was

#        running in the previous runlevel and it wasn't stopped

#        in the runlevel transition (most Debian services don't

#        have K?? links in rc{,,,,} )

#

# Author:    Miquel van Smoorenburg <miquels@cistron.nl>

#        Bruce Perens <Bruce@Pixar.com>

#

# Version:    @(#)rc  2.78  -Nov-  miquels@cistron.nl

#

# 一. 参考文档：

#     . inittab脚本启动解析

#         http://blog.chinaunix.net/uid-17188120-id-4073497.html

#     . Customizing the SDK Splash Screen

#         http://processors.wiki.ti.com/index.php/Customizing_the_SDK_Splash_Screen

#     . psplash进度条旋转成功

#         http://www.xuebuyuan.com/1511619.html

#

#                                    -- 深圳 南山平山村 曾剑锋 

##

##

## /etc/default/rcS

##

## Default settings for the scripts in /etc/rcS.d/

##

## For information about these variables see the rcS() manual page.

##

## This file belongs to the "initscripts" package.

#

## delete files in /tmp during boot older than x days.

## '' means always, - or 'infinite' disables the feature

#TMPTIME=

#

## spawn sulogin during boot, continue normal boot if not used in  seconds

#SULOGIN=no

#

## do not allow users to log in until the boot has completed

#DELAYLOGIN=no

#

## assume that the BIOS clock is set to UTC time (recommended)

#UTC=yes

#

## be more verbose during the boot process

#VERBOSE=no

#

## automatically repair filesystems with inconsistencies during boot

#FSCKFIX=no

. /etc/default/rcS

export VERBOSE

# 在rcS中设置的一些环境变量

# PATH=/sbin:/bin:/usr/sbin:/usr/bin

# runlevel=S

# prevlevel=N

# umask

# export PATH runlevel prevlevel

#

# exec /etc/init.d/rc S

# 这个函数名可以认为是重置进度条进度

startup_progress() {

    # 当前进度大小=上一次的进度+上每次的进度的变化值

    step=$(($step + $step_change))

    if [ "$num_steps" != "" ]; then

        # 这里相当于重新计算当前step占进度条的百分比

        progress=$((($step * $progress_size / $num_steps) + $first_step))

    else

        # 直接就是100%了

        progress=$progress_size

    fi

    #echo "PROGRESS is $progress $runlevel $first_step + ($step of $num_steps) $step_change $progress_size"

    #if type psplash-write >/dev/null 2>&1; then

    #    TMPDIR=/mnt/.psplash psplash-write "PROGRESS $progress" || true

    #fi

    # 将上面的progress的值写入fifo中去，echo的值是固定的。

    if [ -e /mnt/.psplash/psplash_fifo ]; then

        echo "PROGRESS $progress" > /mnt/.psplash/psplash_fifo

    fi

}

#

# Start script or program.

#

# 启动脚本函数

startup() {

    # Handle verbosity

    # VERBOSE=no, 不显示这一部分内容

    [ "$VERBOSE" = very ] && echo "INIT: Running $@..."

    case "$1" in

        *.sh)

            # Source shell script for speed.

            # 这里相当于直接执行脚本，丢弃了参数

            (

                trap - INT QUIT TSTP

                scriptname=$

                shift

                . $scriptname

            )

            ;;

        *)

            # 执行参数里命令

            "$@"

            ;;

    esac

    startup_progress

}

# Ignore CTRL-C only in this shell, so we can interrupt subprocesses.

# 这里就是捕捉INT QUIT TSTP三个信号，执行“：”，实际就是忽略这三个信号，防止脚本执行时使用ctrl-C 就退出脚本

trap ":" INT QUIT TSTP

# Set onlcr to avoid staircase effect.

# 设置onlcr避免楼梯的效果。

stty onlcr >&

# Now find out what the current and what the previous runlevel are.

runlevel=$RUNLEVEL

#echo "danny add"

echo  $

sleep

# Get first argument. Set new runlevel to this argument.

# 由于传进来的参数的$=S，所以这里可以断定的是runlevel是S

[ "$1" != "" ] && runlevel=$

if [ "$runlevel" = "" ]

then

    echo "Usage: $0 <runlevel>" >&

    exit

fi

# 目前没有看到由有关PREVLEVEL相关的内容，这里previous是N

previous=$PREVLEVEL

[ "$previous" = "" ] && previous=N

export runlevel previous

# Is there an rc directory for this new runlevel?

if [ -d /etc/rc$runlevel.d ]

then

    # Find out where in the progress bar the initramfs got to.

    PROGRESS_STATE=

    #if [ -f /dev/.initramfs/progress_state ]; then

    #    . /dev/.initramfs/progress_state

    #fi

    # Split the remaining portion of the progress bar into thirds

    # 感觉这里可以认为是：已经出了一部分的脚本了，这部分内容也应该算进去

    # 所以给出一部分进度条的空间出来，这样，进度条就不像是从0开始，至少

    # 当我们看到图像的时候，psplash这个进程已经跑起来了。

    progress_size=$((( - $PROGRESS_STATE) / ))

    # 这里的runlevel是S

    case "$runlevel" in

        |)

            # Count down from - to  and use the entire bar

            first_step=-

            progress_size=

            step_change=

            ;;

        S)

            # Begin where the initramfs left off and use /

            # of the remaining space

            first_step=$PROGRESS_STATE

            progress_size=$(($progress_size * ))  # 剩下2/

            step_change=

            ;;

        *)

            # Begin where rcS left off and use the final / of

            # the space (by leaving progress_size unchanged)

            first_step=$(($progress_size *  + $PROGRESS_STATE))

            step_change=

            ;;

    esac

    num_steps=

    for s in /etc/rc$runlevel.d/[SK]*; do

        case "${s##/etc/rc$runlevel.d/S??}" in

            gdm|xdm|kdm|reboot|halt)

                break

                ;;

        esac

        num_steps=$(($num_steps + ))

    done

    step=

    # First, run the KILL scripts.

    # 先结束掉需要结束的进程

    if [ $previous != N ]

    then

        for i in /etc/rc$runlevel.d/K[-][-]*

        do

            # Check if the script is there.

            [ ! -f $i ] && continue

            # Stop the service.

            startup $i stop

        done

    fi

    # Now run the START scripts for this runlevel.

    for i in /etc/rc$runlevel.d/S*

    do

        [ ! -f $i ] && continue

        # 这里的previous=N，可以不用关心

        if [ $previous != N ] && [ $previous != S ]

        then

            #

            # Find start script in previous runlevel and

            # stop script in this runlevel.

            #

            suffix=${i#/etc/rc$runlevel.d/S[-][-]}

            stop=/etc/rc$runlevel.d/K[-][-]$suffix

            previous_start=/etc/rc$previous.d/S[-][-]$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.

            #

            [ -f $previous_start ] && [ ! -f $stop ] && continue

        fi

        case "$runlevel" in

            |)

                startup $i stop

                ;;

            *)

                startup $i start

                ;;

        esac

    done

fi

#Uncomment to cause psplash to exit manually, otherwise it exits when it sees a VC switch

if [ "x$runlevel" != "xS" ] && [ ! -x /etc/init.d/xserver-nodm ]; then

    . /etc/init.d/qt.sh

#    if type psplash-write >/dev/null >&; then

#        TMPDIR=/mnt/.psplash psplash-write "QUIT" || true

#        umount /mnt/.psplash

#    fi

fi