Shulou(Shulou.com)06/02 Report--

Busybox: Swiss Army knife, which contains a lot of small orders.

STEP 1: build directory structure

Create the root file system directory, which mainly includes the following directories

/ dev / etc / lib / usr / var / proc / tmp / home/root / mnt / bin / sbin / sys#mkdir / home/rootfs#cd / home/rootfs#mkdir dev etc lib usr var proc tmp home root mnt sys

STEP 2: build / bin / sbin linuxrc using busybox

Enter the busybox-1.16.1 directory and execute

# make defconfig#make menuconfigBusybox Setting-> Build Options-> / / 1 choose to compile busybox statically [*] Build BusyBox as a static binary (no shared libs) / / 2. Specify the cross compiler as (/ usr/local/arm/4.3.2/bin/arm-linux-) Cross Compiler prefixInstallation Options-> (choose the generated file storage directory, or you can put it directly under rootfs without copying) / / 3. Select Don't use / usr Busybox Library Tuning--- > [*] Username completion [*] Fancy shell prompts [*] Query cursor position from terminal / / 4. The compiled busybox shell command interpreter supports the display of current path and host information

Save exit

# make # make install

In the busybox directory, you will see the _ install directory, which contains three files / bin / sbin linuxrc. Copy these three directories or files to the rootfs folder you created in the first step.

# cp bin/ sbin/ linuxrc / home/rootfs-ra

Be sure to take the parameter-a with you, because most of the bin directories are links. If you don't have the parameter-a, you will copy it accordingly after you copy it, instead of in the form of links.

STEP 3 build etc directory: (mainly etc/inittab files, etc/init.d/rcs, etc/fstab)

1) enter the etc directory of the root file system rootfs, and do the following:

Copy Busybox-1.16.1/examples/bootfloopy/etc/* to the current directory

# cp-r busybox-1.16.1/examples/bootfloopy/etc/* rootfs/etc

Modify inittab, (create other child processes based on it)

The original file is:

1:: sysinit:/etc/init.d/rcS 2 tty2::askfirst:-/bin/sh: respawn:-/bin/sh 3 tty2::askfirst:-/bin/sh 4:: ctrlaltdel:/bin/umount-a-r

After modification, it is:

-(1): boot-free login, directly open shell (the preceding number is the line number)

1:: sysinit:/etc/init.d/rcS 2 #:: respawn:-/bin/sh 3 #:: respawn:-/bin/login 4 console::askfirst:-/bin/sh 5 # tty2::askfirst:-/bin/sh 6:: ctrlaltdel:/bin/umount-a-r

-(2): login is required when starting the computer (the preceding number is the line number)

1:: sysinit:/etc/init.d/rcS 2 #:: respawn:-/bin/sh 3:: respawn:-/bin/login 4 # console::askfirst:-/bin/sh 5 # tty2::askfirst:-/bin/sh 6:: ctrlaltdel:/bin/umount-a-r

2) copy / etc/passwd, / etc/group, / etc/shadow on the virtual machine to rootfs/etc

# cp / etc/passwd rootfs/etc # cp / etc/group rootfs/etc # cp / etc/shadow roofs/etc

For the following three file changes, only the items related to root are saved, and the contents will vary according to the situation.

Change passwd to root:x:0:0:root:/root:/bin/sh, that is, save only items related to root, and finally change to / bin/ash.

Change group to root:x:0:root

Change the shadow to root:$1 $x9yv1WlBandABJ2v9jOlOc9xWUniqwPs.Fr14034VOUR 99999WlBJUR:

You need to enter a user name and password when logging in to the development board, which is the same as the virtual machine.

3) modify profile

PATH=/bin:/sbin:/usr/bin:/usr/sbin / / executable program environment variable export LD_LIBRARY_PATH=/lib:/usr/lib / / dynamic link library environment variable / bin/hostname osee USER= "`id-un`" LOGNAME=$USER HOSTNAME='/bin/hostname' PS1=' [\ u@\ h\ W] #'/ displays hostname, current path and other information:

4) modify the etc/init.d/rc.S file (add auto-execute command) #! / bin/sh

/ bin/mount-n-t ramfs ramfs / var/ bin/mount-n-t ramfs ramfs / tmp / bin/mount-n-t sysfs none / sys / bin/mount-n-t ramfs none / dev/ bin/mkdir / var/tmp / bin/mkdir / var/modules / bin/mkdir / var/run / bin/mkdir / var/log / bin/mkdir-p / dev/pts / / telnet Service needs / Bin/mkdir-p / dev/shm / / telnet service requires # echo / sbin/mdev > / proc/sys/kernel/hotplug//USB auto-mount / sbin/mdev-s / / start mdev to automatically create device file node under / dev / bin/mount-a # configure network # # # / sbin/ifconfig lo 127.0.0.1 netmask 255.0.0.0 / sbin/ifconfig eth0 192.168.1.70 / sbin/ifconfig eth0 netmask 255.255.255.0 / sbin/route add default gw 192.168.1.1 eth0 / sbin/ifconfig eth2 192.168.1.71 netmask 255.255.255.0 / sbin/route add default gw 192.168.1.1 eth2

5) modify the etc/fstab file and add the following files to mount the proc tmpfs file system

# device mount-point type options dump fsck order none / dev/pts devpts mode=0622 0 0 tmpfs / dev/shm tmpfs defaults 0 0 proc / proc proc defaults 0 0

STEP 4 builds the lib directory:

(~ / at91/x-tools/arm-zch-linux-gnueabi/arm-zch-linux-gnueabi/sysroot/lib I just copy the SO file in this directory)

1) # cd / usr/local/arm/4.3.2/arm-none-linux-gnueabi/libc/armv4t/lib

Copy the following dynamic libraries to rootfs/lib

# cp * so* roofs/lib-a

2) # cd / usr/local/arm/4.3.2/arm-none-linux-gnueabi/libc/armv4t/usr/lib

Copy the following dynamic libraries to rootfs/lib

# cp. / libstdc++.so.* rootfs/lib-a

STEP 5 build the lmdev directory:

Method 1: create the device file cat / proc/devices statically

Mknod console c 5 1mknod null c 1 3mknod ttySAC0 c 204 64mknod mtdblock0 b 31 0

Method 2: create a device file using mdev

Make sure the kernel sets CONFIG_SYSFS CONFIG_TMPFS

Run mdev automatically when the kernel starts

Modify etc/fstab to automatically mount the root file system modify etc/init.d/rcS to join the autorun command.

Summary

The above is the detailed explanation of the steps of porting busybox to build the minimum root file system introduced by the editor. I hope it will be helpful to you. If you have any questions, please leave me a message and the editor will reply to you in time. Thank you very much for your support to the website!

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