linux根文件系统树制作

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   系统环境：Centos 6.5

   板子芯片：s3c2440

   内核版本：linux 3.0

      编译器：arm-linux-gcc 4.5.4

          作者：Lu Zengmeng <[e-mail]>

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1、创建根文件目录树

[monster@localhost ~]$ mkdir rootfs

[monster@localhost ~]$ cd rootfs/
[monster@localhost rootfs]$ mkdir -p {apps,bin,data,dev,info,proc,root,sbin,sys,tmp,var,etc/{,init.d,dropbear},mnt/{,usb,sdc,nfs,dev},usr/{,bin,sbin,lib,sharre},lib/{,modules/{,3.0.0}}}
[monster@localhost rootfs]$ tree -L 3
.
├── apps
├── bin
├── data
├── dev
├── etc
│   ├── dropbear
│   └── init.d
├── info
├── lib
│   └── modules
│       └── 3.0.0
├── mnt
│   ├── dev
│   ├── nfs
│   ├── sdc
│   └── usb
├── proc
├── root
├── sbin
├── sys
├── tmp
├── usr
│   ├── bin
│   ├── lib
│   ├── sbin
│   └── sharre
└── var

27 directories, 0 files
[monster@localhost rootfs]$ 
时静态创建这两个设备文件，否则在系统启动时将提示
Waring：unable to open an initial console:
[monster@localhost rootfs]$ sudo mknod -m666 dev/null c 1 3
[monster@localhost rootfs]$ sudo mknod -m666 dev/console c 5 1
[monster@localhost rootfs]$ sudo mknod -m666 dev/ttyS0 c 4 64
[monster@localhost rootfs]$ sudo mknod -m666 dev/ttySAC0 c 4 64
[monster@localhost rootfs]$ sudo mknod dev/mtdblock0 b 31 0
[monster@localhost rootfs]$ sudo mknod dev/mtdblock1 b 31 1
[monster@localhost rootfs]$ sudo mknod dev/mtdblock2 b 31 2
[monster@localhost rootfs]$ sudo mknod dev/mtdblock3 b 31 3
[monster@localhost rootfs]$ sudo mknod dev/mtdblock4 b 31 4
[monster@localhost rootfs]$ sudo mknod dev/mtdblock5 b 31 5 
[monster@localhost rootfs]$ sudo mknod dev/mtdblock6 b 31 6 
[monster@localhost rootfs]$ sudo mknod dev/mtdblock7 b 31 7  
[monster@localhost rootfs]$ sudo mknod dev/mtdblock8 b 31 8 
[monster@localhost rootfs]$ ll dev/
总用量 0
crw-rw-rw- 1 root root  5,  1 10月 22 00:39 console
brw-r--r-- 1 root root 31,  0 10月 22 00:39 mtdblock0
brw-r--r-- 1 root root 31,  1 10月 22 00:39 mtdblock1
brw-r--r-- 1 root root 31,  2 10月 22 00:39 mtdblock2
brw-r--r-- 1 root root 31,  3 10月 22 00:39 mtdblock3
brw-r--r-- 1 root root 31,  4 10月 22 00:40 mtdblock4
brw-r--r-- 1 root root 31,  5 10月 22 00:40 mtdblock5
brw-r--r-- 1 root root 31,  6 10月 22 00:40 mtdblock6
brw-r--r-- 1 root root 31,  7 10月 22 00:40 mtdblock7
brw-r--r-- 1 root root 31,  8 10月 22 00:40 mtdblock8
crw-rw-rw- 1 root root  1,  3 10月 22 00:38 null
crw-rw-rw- 1 root root  4, 64 10月 22 00:39 ttyS0
crw-rw-rw- 1 root root  4, 64 10月 22 00:39 ttySAC0
[monster@localhost rootfs]$ ln -s /tmp var/log
[monster@localhost rootfs]$ ln -s /tmp var/run
[monster@localhost rootfs]$ ln -s /tmp var/tmp
[monster@localhost rootfs]$ ls -l var/
总用量 0
lrwxrwxrwx 1 monster monster 4 10月 22 00:42 lock -> /tmp
lrwxrwxrwx 1 monster monster 4 10月 22 00:47 log -> /tmp
lrwxrwxrwx 1 monster monster 4 10月 22 00:47 run -> /tmp
lrwxrwxrwx 1 monster monster 4 10月 22 00:47 tmp -> /tmp
[monster@localhost rootfs]$ cp -af /opt/buildroot-2012.08/arm920t/usr/arm-unknown-linux-uclibcgnueabi/lib/*so* lib/
[monster@localhost etc]$ ls
dropbear  init.d
[monster@localhost etc]$ vim inittab
# /etc/inittab
#
# Copyright (C) 2011 fulinux <[e-mail]>
#
# Note: BusyBox init doesn't support runlevels. The runlevels field is
# completely ignored by BusyBox init. If you want runlevels, use sysvinit.
#
# Format for each entry: <id>:<runlevels>:<action>:<process>
#
# id == tty to run on, or empty for /dev/console.
# If specified, then /dev/$id device must exist
# runlevels == ignored, busybox doesn't support it
# action == one of sysinit, respawn, askfirst, wait, and once
# process == program to run
# Startup the system
# mount all the file systems specified in /etc/fstab
::sysinit:/bin/mount -a
#Use mdev as hotplug to auto mount USB storage or SD card
::sysinit:/bin/echo /sbin/mdev > /proc/sys/kernel/hotplug
#Use mdev to auto generate the device node in /dev path
::sysinit:/sbin/mdev -s
#make shm, pts support
::sysinit:/bin/mkdir -p /dev/pts
::sysinit:/bin/mkdir -p /dev/shm
::sysinit:/bin/mount -t devpts devpts /dev/pts
#Mount our apps/info partition
null::wait:/bin/mount -o sync,noatime,ro -t jffs2 /dev/mtdblock6 /apps
null::wait:/bin/mount -o sync,noatime,ro -t jffs2 /dev/mtdblock7 /info
#Set hostname
null::sysinit:/bin/hostname -F /etc/hostname
#Enable console logon
null::respawn:/sbin/getty -L ttyS0 115200 vt100
# now run any rc scripts
null::wait:/etc/init.d/rcS
# system daemon
null::respawn:/sbin/syslogd -n
null::respawn:/sbin/klogd -n
# Stuff to do before rebooting
null::shutdown:/bin/umount /apps
null::shutdown:/bin/umount /info
null::shutdown:/bin/killall klogd
null::shutdown:/bin/killall syslogd
null::shutdown:/bin/umount -a -r
#null::shutdown:/sbin/swapoff -a
创建/etc/init.d/rcS 脚本
[monster@localhost etc]$ vim init.d/rcS
#!/bin/sh
# Copyright (C) 2011 fulinux <[e-mail]>
# Start all init scripts in /etc/init.d
# executing them in numerical order.
#
for i in /etc/init.d/S??* ; do
$i
done
配置网卡启动脚本

2、dev目录下创建设备节点

因为内核挂载完文件系统后，init 进程需要用到/dev/console 和/dev/null 这两个设备文件来调用 mdev 构建 dev，所以必须在制作文件系统

3、var目录下创建符号链接

[monster@localhost rootfs]$ ln -s /tmp var/lock

5、拷贝交叉编译器中的动态库到相应的目录下

[monster@localhost rootfs]$ cp -af /opt/buildroot-2012.08/arm920t/usr/arm-unknown-linux-uclibcgnueabi/sysroot/lib/*so* lib/

6、etc/目录下创建一些文件

创建inittab文件

[monster@localhost rootfs]$ cd etc/

[monster@localhost etc]$ vim init.d/S01_network

<span style="font-size:14px;">#!/bin/shifconfig eth0 192.168.1.111 netmask 255.255.255.0 up</span>

创建支持/apps/etc 目录下的启动脚本
[monster@localhost etc]$ vim init.d/S99_rcsApp

<span style="font-size:14px;">#!/bin/sh# Copyright (C) 2011 fulinux <[e-mail]># # Start all init scripts in /apps/etc/init.d# executing them in numerical order.#if (test -d /apps/etc/init.d)thenfor i in /apps/etc/init.d/S??* ; do$idonefi</span>

修改 init.d 目录下的文件权限
[monster@localhost etc]$ chmod 777 init.d/*
[monster@localhost etc]$ ll init.d/
总用量 12
-rwxrwxrwx 1 monster monster 179 10月 22 01:11 rcS
-rwxrwxrwx 1 monster monster  63 10月 22 01:14 S01_network
-rwxrwxrwx 1 monster monster 236 10月 22 01:16 S99_rcsApp

创建 fstab 文件

[monster@localhost etc]$ vim fstab

<span style="font-size:14px;"># /etc/fstab: static file system information.# Copyright (C) 2011 fulinux <[e-mail]>##<File system> <mount pt> <type> <options> <dump> <pass>#devpts /dev/pts devpts defaults 0 0#/dev/root / ext2 rw,noauto 0 1proc /proc proc defaults 0 0tmpfs /tmp tmpfs defaults 0 0tmpfs /dev tmpfs defaults 0 0sysfs /sys sysfs defaults 0 0</span>

创建 hostname,hosts,TZ 文件
[monster@localhost etc]$ echo "root" > hostname
[monster@localhost etc]$ echo "127.0.0.1 localhost" >> hosts
[monster@localhost etc]$ echo "127.0.0.1 localhost" >> hostsecho "MST7MDT" >> TZ^C
[monster@localhost etc]$ echo "MST7MDT" >> TZ
[monster@localhost etc]$ echo "Copyright (C) 2015 luzengmeng<[e-mail]>" >> issue

创建profile文件

[monster@localhost etc]$ vim profile

<span style="font-size:14px;"># /etc/profile: system-wide .profile file for the Bourne shells.export PATH=\/bin:\/sbin:\/usr/bin:\/usr/sbin:\/usr/local/bin:\/apps/bin:\/apps/tools:\/apps/tslib/bin\# If running interactively, then:if [ "$PS1" ]; thenif [ "$BASH" ]; thenexport PS1="[\u@\h \W]\\$ "alias ll='/bin/ls --color=tty -laFh'alias ls='/bin/ls --color=tty -F'exportLS_COLORS='no=00:fi=00:di=01;34:ln=01;36:pi=40;33:so=01;35:do=01;35:bd=40;33;01:cd=40;33;01:or=40;31;01:ex=01;32:*.tar=01;31:*.tgz=01;31:*.arj=01;31:*.taz=01;31:*.lzh=01;31:*.zip=01;31:*.z=01;31:*.Z=01;31:*.gz=01;31:*.bz2=01;31:*.deb=01;31:*.rpm=01;31:*.jar=01;31:*.jpg=01;35:*.jpeg=01;35:*.png=01;35:*.gif=01;35:*.bmp=01;35:*.pbm=01;35:*.pgm=01;35:*.ppm=01;35:*.tga=01;35:*.xbm=01;35:*.xpm=01;35:*.tif=01;35:*.tiff=01;35:*.mpg=01;35:*.mpeg=01;35:*.avi=01;35:*.fli=01;35:*.gl=01;35:*.dl=01;35:*.xcf=01;35:*.xwd=01;35:';elseif [ "`id -u`" -eq 0 ]; thenexport PS1='>: 'elseexport PS1='>: 'fifi# System Settingset -o vialias ll='ls -l'export USER=`id -un`export LOGNAME=$USERexport HOSTNAME=`/bin/hostname`export HISTSIZE=1000export HISTFILESIZE=1000export PAGER='/bin/more 'export EDITOR='/bin/vi'export INPUTRC=/etc/inputrcexport DMALLOC_OPTIONS=debug=0x34f47d83,inter=100,log=logfileexport VAR1=export VAR2=export VAR3=export VAR4=export VAR5=export LD_LIBRARY_PATH=/lib:/usr/lib/# QT Extendded 4.4.3 Settingexport QTDIR=/apps/qt-extended-4.4.3export QWS_MOUSE_PROTO='TSLIB:/dev/event0'export QWS_DISPLAY='LinuxFB:/dev/fb0'export QWS_DISPLAY='LinuxFB:mmWidth240:mmHeight320:0'export QWS_SIZE='240x320'export QT_PLUGIN_PATH=$QTDIR/plugins/export QT_QWS_FONTDIR=$QTDIR/lib/fontsexport PATH=$QTDIR/bin:$PATHexport LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$QTDIR/lib# Touch Scree tslib Settingexport TSLIB_ROOT=/apps/tslibexport TSLIB_CONFFILE=$TSLIB_ROOT/etc/ts.confexport TSLIB_CALIBFILE=$TSLIB_ROOT/etc/pointercalexport TSLIB_TSDEVICE=/dev/event0export TSLIB_CONSOLEDEVICE=noneexport TSLIB_FBDEVICE=/dev/fb0fi;</span>

创建指定一些协议所使用的端口号文件 protocols
[monster@localhost etc]$ vim protocols

<span style="font-size:14px;"># /etc/protocols:# $Id: protocols,v 1.1.1.1 2001/09/12 19:03:24 andersee Exp $# # Internet (IP) protocols# from: @(#)protocols 5.1 (Berkeley) 4/17/89# Updated for NetBSD based on RFC 1340, Assigned Numbers (July 1992).ip 0 IP # internet protocol, pseudo protocol numbericmp 1 ICMP # internet control message protocoligmp 2 IGMP # Internet Group Managementggp 3 GGP # gateway-gateway protocolipencap 4 IP-ENCAP # IP encapsulated in IP (officially ``IP'')st 5 ST # ST datagram modetcp 6 TCP # transmission control protocolegp 8 EGP # exterior gateway protocolpup 12 PUP # PARC universal packet protocoludp 17 UDP # user datagram protocolhmp 20 HMP # host monitoring protocolxns-idp 22 XNS-IDP # Xerox NS IDPrdp 27 RDP # "reliable datagram" protocoliso-tp4 29 ISO-TP4 # ISO Transport Protocol class 4xtp 36 XTP # Xpress Tranfer Protocolddp 37 DDP # Datagram Delivery Protocolidpr-cmtp 39 IDPR-CMTP # IDPR Control Message Transportrspf 73 RSPF #Radio Shortest Path First.vmtp 81 VMTP # Versatile Message Transportospf 89 OSPFIGP # Open Shortest Path First IGPipip 94 IPIP # Yet Another IP encapsulationencap 98 ENCAP # Yet Another IP encapsulation</span>

创建mdev.conf文件

mdev 会在/etc 目录下找 mdev 的配置文件: mdev.conf. 如果该文件不存在，那么在执行 mdev –s 这个命令时，
会提示找不到 mdev.conf， 这时我们可以建一个空的 mdev.conf 文件解决这个问题。 下面创建使用 mdev 自动挂载 u 盘和 SD 卡的配置/etc/mdev.conf

[monster@localhost etc]$ vim mdev.conf

<span style="font-size:14px;">sd[a-z][0-9] 0:0 0777 @(mount /dev/$MDEV /mnt/usb)sd[a-z] 0:0 0777 $(umount /mnt/usb)ub[a-z][0-9] 0:0 0777 @(mount /dev/$MDEV /mnt/usb)ub[a-z] 0:0 0777 $(umount /mnt/usb)mmcblk[0-9]p[0-9] 0:0 0777 @(mount /dev/$MDEV /mnt/sdc)mmcblk[0-9] 0:0 0777 $(umount /mnt/sdc)</span>

创建用户组group文件
[monster@localhost etc]$ vim group
root:x:0:root
它的格式如下：
groupname:password:gid:members
第一个字段为用户组名称
第二个字段为用户组密码，当为 x 时密码是映射到/etc/gshadow 中的，是非逆的
第三个字段为 GID，及组号，为正整数或 0，0 被付于了 root 用户组；系统通常会预留一些较靠前的 GID 给系统虚拟用户之用，每个系统预留的
GID 都不同，Fedora 预留了 500 个，所以我们添加新用户组时是从 500 开始的。GID 的范围由/etc/login.defs 中的 GID_MIN 和 GID_MAX 决定
第四个字段为用户列表，每个用户间用逗号分隔
这里的 password 代表组口令，很少用到。它可使原先不在这个群组中的用户可以通过 newgrp 命令暂时继承该组的权限，使用 newgrp 命令时会新开一个 shell。口令的加密方式和 passwd 文件中的口令一样，所以如果需设置组口令，要用 passwd 程序虚设一个用户，再把该用户password节中的加密口令拷贝到/etc/group 文件中。members 列代表组成员，我们可把需加入该组的用户以逗号分隔添加到这里即可。同一组的成员可继承该组所拥有的权限。

创建用户passwd文件

[monster@localhost etc]$ vim psswd

 root:x:0:0:root:/:/bin/sh

它的格式如下：
username:password:uid:gid:gecos:homedir:shell
第一个字段为登录名
第二个字段为口令，一般被映射到 shadow 文件中
第三个字段为 UID
第四个字段为 GID
第五个字段为用户名全称，gecos 是通用电子计算机操作系统的缩写，是 Bell 实验室中的一台大型主机。
第六个字段为用户根目录
第七个字段为用户所用 SHELL 的类型
Unix 系统最初是用明文保存密码的，后来由于安全的考虑，采用 crypt()算法加密密码并存放在/etc/passwd 文件。现在，由于计算机处理能力的提高，使密码破解变得越来越容易。/etc/passwd 文件是所有合法用户都可访问的，大家都可互相看到密码的加密字符串，这给系统带来很大的安全威胁。现代的 Unix 系统使用影子密码系统，它把密码从/etc/pa sswd 文件中分离出来，真正的密码保存在/etc/shadow 文件中，shadow文件只能由超级用户访问。这样入侵者就不能获得加密密码串，用于破解。使用 shadow 密码文件后，/etc/passwd 文件中所有帐户的 password域的内容为"x"，如果 password 域的内容为"*"，则该帐号被停用。使用 passwd 这个程序可修改用户的密。
创建密码映射 shadow 文件
[monster@localhost etc]$ vim shadow
root::0:0:99999:7:::

7、在文件系统中安装busybox

[monster@localhost ~]cd

[monster@localhost ~]$ tar -xjf busybox-1.20.2.tar.bz2 
[monster@localhost ~]$ cd busybox-1.20.2
[monster@localhost busybox-1.20.2]$ vim Makefile

#修改 CROSS_COMPILER 为：
CROSS_COMPILE ?= /opt/buildroot-2012.08/arm920t/usr/bin/arm-linux-

[monster@localhost busybox-1.20.2]$ sudo make menuconfig

#选择：
Busybox Settings --->
General Configuration --->
[*] Don't use /usr
Installation Options ("make install" behavior) --->
What kind of applet links to install (as soft-links) --->

(~/rootfs) BusyBox installation prefix 

[monster@localhost busybox-1.20.2]$ sudo make

编译过程略

[monster@localhost busybox-1.20.2]$ file busybox
busybox: ELF 32-bit LSB executable, ARM, version 1 (SYSV), dynamically linked (uses shared libs), stripped
[monster@localhost busybox-1.20.2]$ sudo make install
  ~/rootfs//bin/[ -> busybox
  ~/rootfs//bin/[[ -> busybox
  ~/rootfs//bin/add-shell -> busybox
  ~/rootfs//bin/addgroup -> busybox
  ~/rootfs//bin/adduser -> busybox
  ~/rootfs//bin/arping -> busybox
  ~/rootfs//bin/ash -> busybox

。。。。。。。。

--------------------------------------------------
You will probably need to make your busybox binary
setuid root to ensure all configured applets will
work properly.
--------------------------------------------------

[monster@localhost busybox-1.20.2]$ ls ../rootfs/
apps  bin  data  dev  etc  info  lib  mnt  proc  root  sbin  sys  tmp  usr  var

8、移植dropbear

首先编译生成 PC 版的，在制作密钥时用到
[monster@localhost dropbear-0.53.1]$ tar -xjf dropbear-0.53.1.tar.bz2 

[monster@localhost dropbear-0.53.1]$ cd dropbear-0.53.1

[monster@localhost dropbear-0.53.1]$ ./configure && make

生成的文件：
dropbear： ssh2 server
dropbearkey: 密钥生成器
dropbearconvert: 可以转换 openssh 的密钥
dbclient: ssh2 client
[monster@localhost dropbear-0.53.1]$ ./dropbearkey -t rsa -f ~/rootfs/etc/dropbear/dropbear_rsa_host_key
Will output 1024 bit rsa secret key to '/home/monster/rootfs/etc/dropbear/dropbear_rsa_host_key'
Generating key, this may take a while...
Public key portion is:
ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAAAgmb5EKxtGdLQ2JuOPljKxFFmzdMj30lvR6EPWzCE2sQ/UV3mSOGvRq27Jo0ANmq+PDu2eLN+EYkwZDdq4svQK8+wH9KWuAnUDZHGB83tE/RwiI2PI1Xpp0/D3/RuoUs9LS8qs2LeLCUEbZlPidTliOUtN4IGqdgxarSkt/hfixHVgI8= [e-mail]
Fingerprint: md5 f0:e3:2c:54:bb:d3:64:0b:e5:ab:a3:11:67:a7:84:4d
[monster@localhost dropbear-0.53.1]$ ./dropbearkey -t dss -f ~/rootfs/etc/dropbear/dropbear_dss_host_key
Will output 1024 bit dss secret key to '/home/monster/rootfs/etc/dropbear/dropbear_dss_host_key'
Generating key, this may take a while...
Public key portion is:
ssh-dss AAAAB3NzaC1kc3MAAACBAP6mfVKWysnBcBQIgTq5fziKRGHm617hi9wZctiX0t+w+CwfSCXmqCw6UMqdBZgOvQnPDPYWzpYH142X3yZ72wps52zHZvIdLbsuxiTq75w26ioEtg4wHghhb65LDGsUFqDgKGiTvvLNaUfJh3AGVZYy0+RZdQ8DuzH5kDI7jIgfAAAAFQC9kUgQA2eWPSPg6rncu0I5umOdYwAAAIAqHUDw1vKn85H40ZfqRorRMGpmWwGLB7PIc5kLX9+Rnc2uP2W1aMpav9oSsIepMdDZzIegD4iNA5KxMiatCQFbOanqfkGTuoswbH+CdJV6EFOe6ncFVBHOqYk0s7cKllGt0ED+5pIamOCPBfc8n1c/uuqOPqodx570E2dWxOExkwAAAIEA+RkSU0l07yP7rEse+7HM/dLJ0gJJs18/a8rehQAH++YZmqTOxboZ4v+6jnI+PQ8jwDjh/GCbfzPg8efc9DoNI5pw9S2ckdiln5R8Rq4GGwhqExdOo8Hv0s+A+5+n+mnNZi3vGn8lr4Q7Ger1yK6cgZ6ywTxM1UrSZn7FbNZipB0= [e-mail]
Fingerprint: md5 e2:ec:7a:7d:9e:97:e1:ba:22:ac:08:82:cb:1f:a8:fc

[monster@localhost ~]$ chmod 666 rootfs/etc/dropbear/dropbear_*

编译arm版

[monster@localhost dropbear-0.53.1]$ make distclean

[monster@localhost dropbear-0.53.1]$ ./configure CC=/opt/buildroot-2012.08/arm920t/usr/bin/arm-linux-gcc --build=i686 --host=arm-linux --disable-zlib
[monster@localhost dropbear-0.53.1]$ make

[monster@localhost dropbear-0.53.1]$ file dropbear dbclient
dropbear: ELF 32-bit LSB executable, ARM, version 1 (SYSV), dynamically linked (uses shared libs), not stripped
dbclient: ELF 32-bit LSB executable, ARM, version 1 (SYSV), dynamically linked (uses shared libs), not stripped

[monster@localhost dropbear-0.53.1]$ mv dbclient ssh

[monster@localhost dropbear-0.53.1]$ /opt/buildroot-2012.08/arm920t/usr/bin/arm-linux-strip dropbear
[monster@localhost dropbear-0.53.1]$ /opt/buildroot-2012.08/arm920t/usr/bin/arm-linux-strip ssh

[monster@localhost dropbear-0.53.1]$ cp dropbear ssh ../rootfs/usr/sbin/

9、在文件系统中创建启动脚本

[monster@localhost rootfs]$ vim etc/init.d/S04_dropbear

  #!/bin/sh
 /usr/sbin/dropbear

[monster@localhost rootfs]$ chmod 777 etc/init.d/S04_dropbear 
[monster@localhost rootfs]$ ls
apps  bin  data  dev  etc  info  lib  mnt  proc  root  sbin  sys  tmp  usr  var
[monster@localhost rootfs]$ OK