====== Linux on Android ======

Based on [[http://lanrat.com/install-debian-on-android/|this]], which is based from [[http://www.saurik.com/id/10|this]].

I want to modify it so that it doesn't rely on debian... made possible mainly by [[http://landley.net/code/aboriginal/|Aboriginal Linux]].

Download Requirements
  * Firstly, get busybox binary from [[http://busybox.net/downloads/binaries/latest/|here]] - use //busybox-armv5l//
  * Get root filesystem from [[http://landley.net/aboriginal/downloads/binaries/root-filesystem/root-filesystem-armv5l.tar.bz2|here]]
  * **(optional)** Get ssh (dropbear) binary from [[http://landley.net/aboriginal/downloads/binaries/extras/dropbearmulti-armv5l|here]]

Prepare Linux Image
  * Create 500MB (as needed) image file <code>dd if=/dev/zero of=linux.img bs=1024 count=500K</code>
  * Format for ext2 filesystem <code>mke2fs -b 1024 -m 0 -F linux.img</code>
  * Loop-mount the image <code>mkdir -p loopfs ; mount -o loop linux.img loopfs</code>
  * Extract root filesystem (as root) <code>tar -xvf root-filesystem-armv5l.tar.bz2 ; cp -a root-filesystem-armv5l/* loopfs/</code>
  * Optionally, copy ssh (dropbear) utility <code>cp dropbearmulti-armv5l loopfs/bin/{dropbear,ssh}</code>
  * Unmount and you get yourself a system image in linux.img! <code>umount loopfs ; rmdir loopfs</code>

Linux Start-Up Script
<file bash linux.sh>
#!/system/busybox/ash

THISPATH=${THISPATH:="$(cd $(dirname $0);pwd)"}

export BUSYPATH=${BUSYPATH:="/system/busybox"}
export SYSIMAGE=${SYSIMAGE:="$THISPATH/linux.img"}
export SYSMOUNT=${SYSMOUNT:="$THISPATH/linux"}
export SYSSHELL=${SYSSHELL:="/bin/ash"}
export PATH=$BUSYPATH:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
export TERM=linux
export HOME=/root

DO_VERBOSE=${DO_VERBOSE:="yes"}
DO_MOUNTSYS_RW="no"
DO_MOUNT_LINUX="yes"
DO_NET_SETUP="yes"
DO_CHROOT_LINUX="yes"
DO_NET_CLEANUP="yes"
DO_UMOUNT_LINUX="yes"
DO_MOUNTSYS_RO="no"
DO_REMOVE_SYSMOUNT="no"

# task in functions

must_be_root()
{
	[ "$(id -u)" -ne 0 ] && echo "Must be root! Aborting!" && exit 1
}

mountsys_rw()
{
	[ "$DO_VERBOSE" == "yes" ] && echo "Setup /system RW access..."
	mount -o remount,rw /system
}

mountsys_ro()
{
	[ "$DO_VERBOSE" == "yes" ] && echo "Reset /system RO access..."
	mount -o remount,ro /system
}

mount_linux()
{
	[ "$DO_VERBOSE" == "yes" ] && echo "Mounting Linux Image..."
	[ ! -d $SYSMOUNT ] && DO_REMOVE_SYSMOUNT="yes" && mkdir $SYSMOUNT
	mount -t ext2 -o loop,noatime,nodiratime $SYSIMAGE $SYSMOUNT
	#mount --bind /mnt/sdcard $SYSMOUNT/mnt/sdcard
	#mount --bind /mnt/sdcard2 $SYSMOUNT/mnt/sdcard2
}

umount_linux()
{
	[ "$DO_VERBOSE" == "yes" ] && echo "Un-mounting Linux Image..."
	#umount $SYSMOUNT/mnt/sdcard
	#umount $SYSMOUNT/mnt/sdcard2
	umount $SYSMOUNT
	[ "$DO_REMOVE_SYSMOUNT" == "yes" ] && rmdir $SYSMOUNT
}

net_setup()
{
	[ "$DO_VERBOSE" == "yes" ] && echo "Setting Up Networking..."
	sysctl -w net.ipv4.ip_forward=1 >/dev/null
	# basic settings - using google public dns ipv4 address
	echo "nameserver 8.8.8.8" > $SYSMOUNT/etc/resolv.conf
	echo "nameserver 8.8.4.4" >> $SYSMOUNT/etc/resolv.conf
	echo "127.0.0.1 localhost" > $SYSMOUNT/etc/hosts
}

net_cleanup()
{
	[ "$DO_VERBOSE" == "yes" ] && echo "Cleaning Up Networking..."
	sysctl -w net.ipv4.ip_forward=0 >/dev/null
}
 
chroot_linux()
{
	mount --bind /proc $SYSMOUNT/proc
	mount --bind /sys $SYSMOUNT/sys
	echo "Entering Linux CHROOT..."
	echo 
	echo "If this is your first time using this image,"
	echo "run 'mdev -s' to create /dev nodes!"
	echo 
	chroot $SYSMOUNT $SYSSHELL
	echo 
	echo "...exiting Linux CHROOT!"
	umount $SYSMOUNT/proc
	umount $SYSMOUNT/sys
}

# check parameter

while [ "$1" != "" ]; do
	case $1 in
		--skip-cleanup)
			DO_NET_CLEANUP="no"
			DO_UMOUNT_LINUX="no"
			DO_MOUNTSYS_RO="no"
			;;
		--startup-only)
			DO_CHROOT_LINUX="no"
			DO_NET_CLEANUP="no"
			DO_UMOUNT_LINUX="no"
			DO_MOUNTSYS_RO="no"
			;;
		--cleanup-only)
			DO_MOUNTSYS_RW="no"
			DO_MOUNT_LINUX="no"
			DO_NET_SETUP="no"
			DO_CHROOT_LINUX="no"
			;;
		--quiet) DO_VERBOSE="no" ;;
		*) echo "Unknown parameter '$1'!" ; exit 1 ;;
	esac
	shift
done

# do your thing!

must_be_root
[ "$DO_MOUNTSYS_RW" == "yes" ] && mountsys_rw
[ "$DO_MOUNT_LINUX" == "yes" ] && mount_linux
[ "$DO_NET_SETUP" == "yes" ] && net_setup
[ "$DO_CHROOT_LINUX" == "yes" ] && chroot_linux
[ "$DO_NET_CLEANUP" == "yes" ] && net_cleanup
[ "$DO_UMOUNT_LINUX" == "yes" ] && umount_linux
[ "$DO_MOUNTSYS_RO" == "yes" ] && mountsys_ro

exit 0
</file>

Pre-Image Work
  * Get Aboriginal Linux system-image for armv5l from [[http://landley.net/code/aboriginal/downloads/binaries/system-image/system-image-armv5l.tar.bz2|here]]
  * Get lfs-bootstrap image for armv5l from [[http://landley.net/code/aboriginal/bin/lfs-bootstrap.tar.gz-armv5l|there]] as well
  * Make sure you have QEMU installed in your system
  * Extract the system image - run dev_environment.sh (requires QEMU)
  * Exit and you should find hdb.img
  * Loop mount the image file and copy lfs-bootstrap image and git source tarball into it
  * Re-run dev_environment.sh
  * ...
  * To compile git, use //./configure --prefix=/usr/local --with-python= CFLAGS="${CFLAGS} -static" NO_GETTEXT=1//
  * //to be continued//
  * **(optional)** Get git source code (also, get an armv5l system image and lfs-bootstrap)