#!/bin/sh
# $1 is the kernel version
# this is a really simple way to create an initrd
# if you want to have modules instead of compiling
# support directly into the kernel
# this doesn't deal with RAID LVM 
# This uses busybox

# make basic dir structure
cd ${BUILD_DIRECTORY}/initrd
mkdir bin dev etc etc.ro lib proc sbin var sys usr mnt initrd
cd var
mkdir lock log
cd ../lib
mkdir -p modules/
cd ../usr
mkdir bin

# copy config files
cd ${INSTALL_ROOT}/etc
cp -a hotplug* init.d udev fstab group passwd ${BUILD_DIRECTORY}/initrd/etc.ro/
cp -a hotplug* init.d udev fstab group passwd ${BUILD_DIRECTORY}/initrd/etc/

# copy busybox
cd ${INSTALL_ROOT}/sbin
for file in busybox hotplug
do
	cp -a $file ${BUILD_DIRECTORY}/initrd/sbin/
done
cd ${INSTALL_ROOT}/bin
for file in bash.static od
do
	cp -a $file ${BUILD_DIRECTORY}/initrd/bin/
done
for file in ${INSTALL_ROOT}/lib/libc[-.]* ${INSTALL_ROOT}/lib/ld-*
do
	cp -a $file ${BUILD_DIRECTORY}/initrd/lib
done

# link everything
cd ${BUILD_DIRECTORY}/initrd/sbin/
for i in insmod modprobe pivot_root reboot halt init mesg lsmod rmmod swapon \
         swapoff makedevs
do
	ln -s busybox $i
done

cd ../bin
for i in ash ls echo mount ln mkdir mknod chown chmod umount tar basename \
         chgrp cat chroot cp cut dd df dirname du env expr false head id \
	 install md5sum mv printf pwd realpath rm rmdir sleep sort sync tail \
	 tee touch tr true uname uniq who whoami yes which readlink sed dmesg \
	 more awk test wc
do
	ln -s ../sbin/busybox $i
done
for i in bash sh
do
	ln -s bash.static $i
done
cd ../usr/bin
for i in grep bunzip2 gzip gunzip unzip patch find xargs
do
	ln -s ../../sbin/busybox $i
done

# Copy kernel modules
cp -a ${INSTALL_ROOT}/lib/modules/$1 ${BUILD_DIRECTORY}/initrd/lib/modules/
cp -a ${INSTALL_ROOT}/lib/firmware ${BUILD_DIRECTORY}/initrd/lib/firmware

# cp console null hd's
cp -a ${INSTALL_ROOT}/dev/console ${BUILD_DIRECTORY}/initrd/dev/
cp -a ${INSTALL_ROOT}/dev/null ${BUILD_DIRECTORY}/initrd/dev/

# create linuxrc
(
cat << EOF
#!/bin/bash

export PATH="/bin:/usr/bin:/sbin:/usr/sbin"

# =================================================== #
# Setting up a suitable environment but no /dev/      #
# =================================================== #
udev_root=/dev
# mount sysfs
echo "Mounting sysfs at /sys"
mount -nt sysfs none /sys
# mount proc
echo "Mounting /proc"
mount -nt proc none /proc
echo "Mounting tmpfs at /etc/"
mount -nt tmpfs none /etc
echo "Copying etc.ro to etc"
cp -a /etc.ro/* /etc
touch /etc/mtab
echo "Mounting ramfs at \$udev_root"
mount -nt ramfs none \$udev_root
mknod \$udev_root/null c 1 3
# create some needed stuff
ln -s /proc/self/fd \$udev_root/fd
ln -s /dev/fd/0 \$udev_root/stdin
ln -s /dev/fd/1 \$udev_root/stdout
ln -s /dev/fd/2 \$udev_root/stderr
mkdir \$udev_root/shm
mkdir \$udev_root/pts
# =================================================== #
# Okay this is where you can add code to load modules #
# =================================================== #
# /sbin/modprobe ipv6


# =================================================== #
# Don't edit past here unless you really know what    #
# you are doing                                       #
# =================================================== #
echo "Executing Hotplug"
for RC in /etc/hotplug/*.rc
do
	\$RC start
done
echo "Getting real root dev"
real_root="\`cat /proc/cmdline | awk '{ for ( i = 1; i <= NF; i++ )  
						if ( \$i ~ /real_root=.*/ )
							print \$i
					}' | awk -F= '{ print \$2 }'\`"
echo "Real Root is \${real_root}"
echo "Creating initial udev device nodes"
number="\`echo \$real_root | sed 's/\/dev\/hd[a-z]//g'\`"
real_dev="\`echo \$real_root | sed 's/[0-9]//g'\`"
letter="\`echo \$real_dev | sed 's/\/dev\/hd//g'\`"
if test \$letter = a || test \$letter = b ; then
	major="3"
elif test \$letter = c || test \$letter = d ; then
	major="22"
elif test \$letter = e || test \$letter = f ; then
	major="33"
elif test \$letter = g || test \$letter = h ; then
	major="34"
else
	echo "Bad real root dev \$real_root"
	exit 1
fi
if test \$letter = a || test \$letter = c ||
   test \$letter = e || test \$letter = g ; then
   	minor="0"
else
	minor="64"
fi
minor="\`expr \$minor + \$number\`"
mknod  \$real_root b \$major \$minor
echo "0x100" > /proc/sys/kernel/real-root-dev
mount -n \${real_root} /mnt
umount -n /proc
umount -n /sys
umount -n /dev
umount -n /etc
cd /mnt
pivot_root . initrd
echo "args to init \$@"
exec chroot . /sbin/init \$@ < /dev/console > /dev/console 2>&1

EOF
) > ${BUILD_DIRECTORY}/initrd/linuxrc

chmod +x ${BUILD_DIRECTORY}/initrd/linuxrc
if [ ! -d ${INSTALL_ROOT} ] ; then
  mkdir ${INSTALL_ROOT}/initrd
fi