私人定制：打造自己的Linux系统

启动流程介绍：

制作Linux小系统之前，我们有必要再了解一下Linux的启动流程：

1、首先Linux要通过POST自检，检查硬件设备有没有故障

2、如果有多块启动盘的话，需要在BIOS中选择启动磁盘

3、启动MBR中的bootloader引导程序

4、加载内核文件

5、执行所有进程的父进程、老祖宗init

6、打印欢迎界面

在Linux的启动流程中，加载内核文件时还需要借助别外两个文件：

1）initrd，是CentOS5上用内存模拟的磁盘设备

2）initramfs，是CentOS6上用内存模拟的文件系统

在启程的流程中，init主要是用来做哪些操作的呢？

init通过调用/etc/inittab这个配置文件，然后再去执行/etc/rc.d/rc.sysinit的系统初始化脚本

启发

到Linux打印欢迎界面后，就说明系统已经启动成功，如果我们要制作一个Linux小系统，我们只需要把它在开机流程中用到的各文件都装载到一起，就可以点亮属于我们自己的系统了，而Linux是一个模块化的操作系统，好多功能组件都是通过模块化的工具来实现的，而且支持动态装载和卸载，我们要是想实现某种功能，只需加载相应的模块即可，就可以实现我们的Linux操作系统大瘦身了。

#!/bin/bash
#拷贝系统安装所需的软件包

SYSTEM_DIR=/home/centos
SYSTEM_NAME=itnihaoOS
ISO_MOUNT_POIONT1=/mnt/cd1
ISO_MOUNT_POIONT2=/mnt/cd2

mount_ISO (){
mkdir ${ISO_MOUNT_POIONT1}
mkdir ${ISO_MOUNT_POIONT2}
mkdir ${SYSTEM_DIR}/Packages  -p
mkdir /home/source
echo "请确保光驱里面有ISO文件，且可以被挂载"
echo "请输入Y/y继续,任意键则退出运行"
read ret
[ ${ret} != "Y" -a ${ret} != "y" ] && exit 1
echo  "echo 默认情况，挂载的是/dev/cdrom到${ISO_MOUNT_POIONT1}"
ls ${ISO_MOUNT_POIONT1} |grep Packages
if [ "$?" == 0 ]
then
echo "光驱已经挂载"
else
echo "正在尝试挂载本地光驱到/mnt/cd1,请稍等片刻"
mount /dev/cdrom  ${ISO_MOUNT_POIONT1}
ls ${ISO_MOUNT_POIONT1} |grep Packages
if [ "$?" != 0 ]
then
echo "光盘挂载不成功，请手动重新挂载，或者尝试本地ISO挂载"
echo "请输入本地ISO的路径:"
read ret
ls ${ret}
[ "$?" != 0 ] && echo "本地ISO不存在或者路径错误，退出运行" && exit 1
[ "$?" == 0 ] && mount -o loop ${ret}  ${ISO_MOUNT_POIONT1}
fi
fi
}


copy_ISO_file (){
awk  '{print $2}' install.log |sed -e '/^$/d' -e 's/^ //g'|grep -v FINISHED|grep -v ":"  >/home/source/packges.list
for packges in $(cat /home/source/packges.list)
do
cp ${ISO_MOUNT_POIONT1}/Packages/$packges*  ${SYSTEM_DIR}/Packages
[ $? != 0 ] && echo "copy  $packges is faied!"&& cp ${ISO_MOUNT_POIONT2}/Packages/$packges*    ${SYSTEM_DIR}/Packages
[ $? != 0 ] && echo "$packges is not exist in ${ISO_MOUNT_POIONT2}/Packages/"
done
rsync -a --exclude=Packages ${ISO_MOUNT_POIONT1}/  ${SYSTEM_DIR}
}


rebuild_repo_xml (){
yum -y install createrepo mkisofs
cd  ${SYSTEM_DIR}
declare -x discinfo=$(head -1 .discinfo)
##########################centos6.3_X64###############################
#mv   ${SYSTEM_DIR}/repodata/*x86_64-comps.xml       ${SYSTEM_DIR}/repodata/comps.xml
#createrepo   -g   ${SYSTEM_DIR}/repodata/comps.xml  ${SYSTEM_DIR}
#createrepo -u "media://$discinfo" -g  ${SYSTEM_DIR}/repodata/comps.xml   ${SYSTEM_DIR}
######################################################################


##########################centos6.4_X64###############################
mv   ${SYSTEM_DIR}/repodata/*x86_64-comps.xml       ${SYSTEM_DIR}/repodata/c6-x86_64-comps.xml
createrepo   -g   ${SYSTEM_DIR}/repodata/c6-x86_64-comps.xml  ${SYSTEM_DIR}
createrepo -u "media://$discinfo" -g  ${SYSTEM_DIR}/repodata/c6-x86_64-comps.xml   ${SYSTEM_DIR}

#mkisofs -o ${SYSTEM_NAME}.iso -b isolinux/isolinux.bin -c isolinux/boot.cat    -no-emul-boot  -boot-load-size 4  -boot-info-table  -R  -J  -v  -V  itnihao  -T ${SYSTEM_DIR}
}

isolinux_cfg (){
cat > ${SYSTEM_DIR}/isolinux/isolinux.cfg <
default auto
timeout 600

#default vesamenu.c32
#prompt 1

display boot.msg

menu background splash.jpg
menu title Welcome to SucunOS 6.6!
menu color border 0 #ffffffff #00000000
menu color sel 7 #ffffffff #ff000000
menu color title 0 #ffffffff #00000000
menu color tabmsg 0 #ffffffff #00000000
menu color unsel 0 #ffffffff #00000000
menu color hotsel 0 #ff000000 #ffffffff
menu color hotkey 7 #ffffffff #ff000000
menu color scrollbar 0 #ffffffff #00000000

label auto
menu label ^Auto Install system
menu default
kernel vmlinuz
append ks=cdrom:/isolinux/ks.cfg initrd=initrd.img

label linux
menu label ^Install or upgrade an existing system
kernel vmlinuz
append initrd=initrd.img
label vesa
menu label Install system with ^basic video driver
kernel vmlinuz
append initrd=initrd.img xdriver=vesa nomodeset
label rescue
menu label ^Rescue installed system
kernel vmlinuz
append initrd=initrd.img rescue
label local
menu label Boot from ^local drive
localboot 0xffff
label memtest86
menu label ^Memory test
kernel memtest
append -
EOF
}
ks_file(){
cat > ${SYSTEM_DIR}/isolinux/ks.cfg <
# Kickstart file automatically generated by anaconda.
#Itnihao OS
#date 2012-04-24
#date 2013-06-28
#version=V1.1
install
text
cdrom
lang en_US.UTF-8
keyboard us
skipx
#network --onboot yes --device eth0 --bootproto static --ip 192.168.122.20 --netmask 255.255.255.0 --gateway 192.168.122.1 --noipv6 --nameserver 114.114.114.114
network --onboot yes
rootpw  itnihao
firewall --service=ssh --port=80:tcp
authconfig --enableshadow --passalgo=sha512
selinux --enforcing
timezone Asia/Shanghai
bootloader --location=mbr --driveorder=sda --append=" rhgb crashkernel=auto quiet"
# The following is the partition information you requested
# Note that any partitions you deleted are not expressed
# here so unless you clear all partitions first, this is
# not guaranteed to work
#clearpart --none
clearpart --all --initlabel
zerombr
#part /boot --fstype=ext4 --size=2000
#part swap --size=5000
#part / --fstype=ext4 --grow --size=200

reboot
#repo --name="CentOS"  --baseurl=cdrom:sr0 --cost=100

%packages
@base
@core
@mysql
@server-policy
@workstation-policy
@parted
@gcc
@gcc-c++
@cmake
@ncurses-devel
@perl
@perl-devel
@bc
@boost-thread
@boost-devel
@gbd
@createrepo
@mysql
@sysstat
@screen
EOF
}
build_new_ISO (){
cd ${SYSTEM_DIR}
mkisofs -o ${SYSTEM_NAME}.iso -input-charset utf-8 -b isolinux/isolinux.bin -c isolinux/boot.cat    -no-emul-boot  -boot-load-size 4  -boot-info-table  -R  -J  -v  -V  itnihao  -T ${SYSTEM_DIR}
}
main (){
mount_ISO
copy_ISO_file
isolinux_cfg
ks_file
rebuild_repo_xml
build_new_ISO
}
main