linux-init

#!/bin/bash

# Exit on first error
set -e
set -x
# Debug
# echo "Env: $(env)"
# echo "Cmdline: $(cat /proc/cmdline)"

rm -f "${UMLDIR}/.exit_code"

save_and_shutdown() {
    # Default exit code
    if [ ! -f "${UMLDIR}/.exit_code" ]; then
        echo 42 > "${UMLDIR}/.exit_code"
    fi

    # save built for host result
    # force clean shutdown
    set +e
    kill -9 $(jobs -p) &>/dev/null
    halt -f &>/dev/null
}


# Create /lib/modules to prevent repeated warnings
sudo mkdir -p /lib/modules/$(uname -r) && sudo depmod -a 2>/dev/null || true


# make sure we shut down cleanly
trap save_and_shutdown EXIT SIGINT SIGTERM

# go back to where we were invoked
cd "${WORKDIR}"

# configure path to include /usr/local
export PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin

# can't do much without proc!
mount -t proc none /proc

# pseudo-terminal devices
mkdir -p /dev/pts
mount -t devpts none /dev/pts

# shared memory a good idea
mkdir -p /dev/shm
mount -t tmpfs none /dev/shm

# sysfs a good idea
mount -t sysfs none /sys

# pidfiles and such like
mkdir -p /var/run
mount -t tmpfs none /var/run

# takes the pain out of cgroups
cgroups-mount

# mount backen[5~d
case ${DOCKER_BACKEND_FS} in
    tmpfs)
	    mount -t tmpfs none /var/lib/docker
	    ;;
    host)
	    echo "Using host filesystem as backend"
	    ;;
    *)
	    echo "Unsupported backend filesystem"
	    exit 1
esac

# enable ipv4 forwarding for docker
echo 1 > /proc/sys/net/ipv4/ip_forward

# configure networking
ip addr add 127.0.0.1 dev lo
ip link set lo up
ip addr add 10.1.1.1/24 dev eth0
ip link set eth0 up
ip route add default via 10.1.1.254


# configure dns (google public)
mkdir -p /run/resolvconf
echo 'nameserver 8.8.8.8' > /run/resolvconf/resolv.conf
mount --bind /run/resolvconf/resolv.conf /etc/resolv.conf


# Start docker daemon
if [ "${QUIET}" -eq 0 ]; then
    docker --storage-driver="${DOCKER_STORAGE_DRIVER}" -d -H unix:///var/run/docker.sock -H tcp://0.0.0.0:2375 &
else
    docker --storage-driver="${DOCKER_STORAGE_DRIVER}" -d -H unix:///var/run/docker.sock -H tcp://0.0.0.0:2375 &>/dev/null &
fi


# Waiting for docker socket
n=0
until [ $n -ge 120 ]; do ((n++)) && sleep 0.1 && test -e /var/run/docker.sock && break; done
test -e /var/run/docker.sock || exit 1


# Print docker information
if [ "${QUIET}" -eq 0 ]; then
    echo '+ docker info'
    docker info
    echo '+ docker version'
    docker version
fi


# reset environment
. "${UMLDIR}/.envp"

# Call command
command=$(cat "${UMLDIR}/.command")
set +e
/bin/bash -xec "${command}"
echo $? > "${UMLDIR}/.exit_code"

(
    set +e
    mount
    df -h
    ls -la /dev/shm
    ls -la /run/shm
    ls -la /run/lock
)