#!/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 init.d udev fstab group passwd ${BUILD_DIRECTORY}/initrd/etc.ro/
cp -a init.d udev fstab group passwd ${BUILD_DIRECTORY}/initrd/etc/

# copy busybox
cd ${INSTALL_ROOT}/sbin
cp -a busybox ${BUILD_DIRECTORY}/initrd/sbin/

# 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 sh 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
do
	ln -s ../sbin/busybox $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 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/ash

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

# =================================================== #
# Setting up a suitable environment but no /dev/      #
# =================================================== #
udev_root=/dev
# mount sysfs
/bin/echo "Mounting sysfs at /sys"
/bin/mount -nt sysfs none /sys
# mount proc
/bin/echo "Mounting /proc"
/bin/mount -nt proc none /proc
/bin/echo "Mounting tmpfs at /etc/"
/bin/mount -nt tmpfs none /etc
/bin/echo "Copying etc.ro to etc"
/bin/cp -a /etc.ro/* /etc
/bin/touch /etc/mtab
/bin/echo "Mounting ramfs at \$udev_root"
/bin/mount -nt ramfs none \$udev_root
# create some needed stuff
/bin/ln -s /proc/self/fd \$udev_root/fd
/bin/ln -s /dev/fd/0 \$udev_root/stdin
/bin/ln -s /dev/fd/1 \$udev_root/stdout
/bin/ln -s /dev/fd/2 \$udev_root/stderr
/bin/mkdir \$udev_root/shm
/bin/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                                       #
# =================================================== #
/bin/echo "Getting real root dev"
real_root="\`/bin/cat /proc/cmdline | /bin/awk '{ for ( i = 1; i <= NF; i++ )  
						if ( \$i ~ /real_root=.*/ )
							print \$i
					}' | /bin/awk -F= '{ print \$2 }'\`"
/bin/echo "Real Root is \${real_root}"
/bin/echo "Creating initial udev device nodes"
number="\`/bin/echo \$real_root | /bin/sed 's/\/dev\/hd[a-z]//g'\`"
real_dev="\`/bin/echo \$real_root | /bin/sed 's/[0-9]//g'\`"
letter="\`/bin/echo \$real_dev | /bin/sed 's/\/dev\/hd//g'\`"
if /bin/test \$letter = a || /bin/test \$letter = b ; then
	major="3"
elif /bin/test \$letter = c || /bin/test \$letter = d ; then
	major="22"
elif /bin/test \$letter = e || /bin/test \$letter = f ; then
	major="33"
elif /bin/test \$letter = g || /bin/test \$letter = h ; then
	major="34"
else
	/bin/echo "Bad real root dev \$real_root"
	exit 1
fi
if /bin/test \$letter = a || /bin/test \$letter = c ||
   /bin/test \$letter = e || /bin/test \$letter = g ; then
   	minor="0"
else
	minor="64"
fi
minor="\`/bin/expr \$minor + \$number\`"
/bin/mknod  \$real_root b \$major \$minor
/bin/echo "0x100" > /proc/sys/kernel/real-root-dev
/bin/mount -n \${real_root} /mnt
/bin/umount -n /proc
/bin/umount -n /sys
/bin/umount -n /dev
/bin/umount -n /etc
cd /mnt
/sbin/pivot_root . initrd
/bin/echo "args to init \$@"
exec /bin/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