Making a Linux root file system using BusyBox

STEP 1: Building the directory structure

Create the root file system directory, mainly including 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 with BusyBox

Enter the busybox-1.16.1 directory and execute

#make Defconfig

#make Menuconfig

Busybox Setting----->
Build Options----->
//1 choose to statically compile the BusyBox
[*] Build BusyBox as a static binary (no shared libs)
//2. Specifies that the cross compiler is
(/usr/local/arm/4.3.2/bin/arm-linux-) Cross Compiler Prefix

Installation Options----->

//3. Select Upper 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 displaying the current path and host information

Save exit

#make
#make Install

In the BusyBox directory, you will see the _install directory with/bin/sbin linuxrc three files.
Copy these three directories or files to the Rootfs folder that you built in the first step.

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

Remember to take the-a parameter, because most of the bin directory is a link, if not with the-a parameter, copy the past will do the corresponding replication, is no longer the form of links

STEP 3 Build etc directory:

1) Enter the ETC directory of the root file system Rootfs and do the following:

copy busybox-1.16.1/examples/bootfloopy/etc/* to current directory
#cp –r busybox-1.16.1/examples/bootfloopy/etc/* rootfs/etc

Revise the Inittab and replace the second item with: Respawn:-/bin/login

Delete the third and fourth lines of code

2) Copy the/etc/passwd on the virtual machine,/etc/group,/etc/shadow to Rootfs/etc

# cp/etc/passwd Rootfs/etc
# Cp/etc/group Rootfs/etc
# Cp/etc/shadow Roofs/etc

Changes to the following three files, only the root-related items, depending on the circumstances of the content will be different.

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

Modify Group to Root:x:0:root

Modify Shadow to Root:$1$x9yv1wlb$abj2v9joloc9xw/y0qwps.:14034:0:99999:7:::

Login to the board to enter the user name password, the same as the virtual machine

3) Modify Profile

Path=/bin:/sbin:/usr/bin:/usr/sbin//Executable program Environment variables

Export ld_library_path=/lib:/usr/lib//dynamic link library environment variables

/bin/hostname sunplusedu

User= "' Id-un '"

Logname= $USER

Hostname= '/bin/hostname '

Ps1= ' [\[email protected]\h \w]# '//Display host name, current path and other information:

4) Modify the ETC/INIT.D/RC. S file

/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 required

/bin/mkdir-p/DEV/SHM//telnet Service required

Echo/sbin/mdev >/proc/sys/kernel/hotplug//usb Auto Mount required

/sbin/mdev-s//Start Mdev automatically create a device file node in/dev

/bin/mount-a

5) Modify the Etc/fstab file to add the following file

none/dev/pts devpts mode=0622 0 0
TMPFS/DEV/SHM TMPFS Defaults 0 0

STEP 4 Build the Lib 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

Making a Linux root file system using BusyBox