After running UML, it is now  possible to connect with adb using
$ adb connect 192.168.0.253

Added init.eth0.sh script to configure tuntap connection to host.
Modified init.uml.rc to run init.eth0.sh on boot.

Added SELinux rules for init.eth0.sh to run during init.

=== To run ===
Install UML utilities
$ sudo apt-get install uml-utilities
$ sudo mv /usr/lib/uml/uml_net /usr/bin/uml_net
$ sudo chmod +x /usr/bin/uml_net

Compile UML userspace
$ . build/envsetup.sh
$ lunch uml-userdebug
$ make -j40

Compile UML Kernel on Android-4.9 branch
$ ARCH=um SUBARCH=x86_64 scripts/kconfig/merge_config.sh
arch/um/configs/x86_64_defconfig kernel/configs/android-base.config
kernel/configs/android-recommended.config
$ make ARCH=um SUBARCH=x86_64 CROSS_COMPILE= -j40

Run UML:
$ ./vmlinux initrd=ramdisk.img ubda=system.img ubdb=userdata.img \
androidboot.hardware=uml mem=256M umid=uml eth0=tuntap,,,192.168.0.254

Connect with adb:
$ adb connect 192.168.0.253

Test: manual

Bug: 32523022
Change-Id: Iaafc0aa701ff7d777226168a078c0a3712a3e6b8
Signed-off-by: Quang Luong <qal@google.com>