Busybox

1. Download the source and patches from the busybox website.

http://www.busybox.net/download.html

The version at the time of writing this is 1.14.1.

2. untar the sources to the directory where you will run the build.

3. patch the sources

patch -p0 <>.patch
e.g patch -p0 <>

4. config the busybox using your favourite config method. I prefer to use xconfig.

5. make your day :) -------- run make

6. once the make has run successful , you would want to install the busybox in a seperate directory which you can later ready to use as the rootfs.

make CONFIG_PREFIX=~/busybox/target install

where I am installing busybox in the /home/nemesis/busybox/target directory

7 cd to the install directory

cd ~/busybox/target

8. There isn't a great deal there

ls -al would return

sbin, bin , usr and linuxrc (a symbolic link to /bin/busybox)



9. Create the dev, dev/pts, etc, etc/init.d, lib, mnt, opt, proc, root, sys, tmp, var, and var/log directories. Also create the device node for the initial console

mkdir dev etc lib mnt opt proc root sys tmp var debug
mkdir etc/init.d
mkdir var/log

sudo mknod dev/console c 5 1
sudo mknod dev/null c 1 3


10. Mount proc and /dev/pts at boot time
===========================

edit /etc/fstab for these filesystems


11. Shared library and library loader
==========================
We still need the
---------- shared libraries (from your toolchain)
---------- library loader (e.g ld-linux.so.3 in the listing below)

nemesis@nemesis-laptop:~/codesourcery/arm-2009q3/arm-none-linux-gnueabi/libc/lib$ ls
ld-2.10.1.so libdl-2.10.1.so libnss_dns.so.2 libresolv-2.10.1.so
ld-linux.so.3 libdl.so.2 libnss_files-2.10.1.so libresolv.so.2
libanl-2.10.1.so libgcc_s.so libnss_files.so.2 librt-2.10.1.so
libanl.so.1 libgcc_s.so.1 libnss_hesiod-2.10.1.so librt.so.1
libBrokenLocale-2.10.1.so libm-2.10.1.so libnss_hesiod.so.2 libSegFault.so
libBrokenLocale.so.1 libmemusage.so libnss_nis-2.10.1.so libthread_db-1.0.so
libc-2.10.1.so libm.so.6 libnss_nisplus-2.10.1.so libthread_db.so.1
libcidn-2.10.1.so libnsl-2.10.1.so libnss_nisplus.so.2 libutil-2.10.1.so
libcidn.so.1 libnsl.so.1 libnss_nis.so.2 libutil.so.1
libcrypt-2.10.1.so libnss_compat-2.10.1.so libpcprofile.so
libcrypt.so.1 libnss_compat.so.2 libpthread-2.10.1.so
libc.so.6 libnss_dns-2.10.1.so libpthread.so.0


--- that's an aweful lot. Copying them indiscriminately will cause our rootfs to be bloated (something we don't want). So just pick what you need. And And And ofcourse strip these libraries :)

nemesis@nemesis-laptop:~/busybox/target/lib$ ~/codesourcery/arm-2009q3/bin/arm-none-linux-gnueabi-strip *


Thats the minimal set for the rootfs


12. Kernel Modules
=================
Now it is time to get our dear modules.

--- go to the kernel build directory
--- issue the following command : make modules

after it has completed successfully , we need to install the modules in our rootfs. Elementary my dear watson!

make INSTALL_MOD_PATH=/path/to/rootfs modules_install

Once we are out of the debugging phase, we would like to strip the modules to slim down.

cd /path/to/rootfs/lib/modules
arm-none-linux-gnueabi-strip `find . –name “*.ko”`