startdockerd

#!/bin/bash

export BUILD_DIR=${BUILD_DIR:-/usr/lib/build}

CONTAINERD_PID=0
DOCKERD_PID=0
WEBSERVER_PID=0

cleanup_and_exit() {
    test -z "$1" && set 0
    if test -n "$2" ; then 
	if test "$1" -ne 0 ; then 
	    echo "$2" >&2
	else
	    echo "$2"
	fi
    fi   
    if test "$1" != 0 ; then
	test -n "$WEBSERVER_PID" -a "$WEBSERVER_PID" != 0 && kill "$WEBSERVER_PID"
	test -n "$DOCKERD_PID" -a "$DOCKERD_PID" != 0 && kill "$DOCKERD_PID"
	test -n "$CONTAINERD_PID" -a "$CONTAINERD_PID" != 0 && kill "$CONTAINERD_PID"
    fi
    exit $1
}


BUILD_ROOT=
IS_UNSHARED=
KILL=
WEBSERVER=

while test -n "$1" ; do
    case "$1" in
	--root)
	    BUILD_ROOT="$2"
	    shift 2
	    ;;
	--webserver)
	    WEBSERVER="$2"
	    shift 2
	    ;;
	--isunshared)
	    IS_UNSHARED=true
	    shift
	    ;;
	--kill)
	    KILL=true
	    shift
	    ;;
	*)
	    break
	    ;;
    esac
done

if test -n "$1" -o -z "$BUILD_ROOT" ; then
    cleanup_and_exit 1 "Usage: startdockerd --root <buildroot>"
    echo "Usage: startdockerd --root <buildroot>"
fi

if test -n "$KILL" ; then
    if test -e "$BUILD_ROOT/.startdockerd.pids" ; then
	read CONTAINERD_PID DOCKERD_PID WEBSERVER_PID < $BUILD_ROOT/.startdockerd.pids
	if test -n "$WEBSERVER_PID" -a "$WEBSERVER_PID" != 0 ; then
	    echo "Stopping local repository server"
	    kill "$WEBSERVER_PID"
	fi
	if test -n "$DOCKERD_PID" -a "$DOCKERD_PID" != 0 ; then
	    echo "Stopping docker daemon"
	    kill "$DOCKERD_PID"
	fi
	if test -n "$CONTAINERD_PID" -a "$CONTAINERD_PID" != 0 ; then
	    echo "Stopping container daemon"
	    kill "$CONTAINERD_PID"
	fi
	rm -f "$BUILD_ROOT/.startdockerd.pids"
    fi
    exit 0
fi

rm -f $BUILD_ROOT/.startdockerd.pids

if test -z "$IS_UNSHARED" ; then
    echo "Unsharing environment"
    # unshare mounts and network
    exec unshare -m -n $BUILD_DIR/startdockerd --isunshared --root "$BUILD_ROOT" --webserver "$WEBSERVER" "$@"
    cleanup_and_exit 1 "exec unshare returned"
fi

# load needed kernel modules
modprobe bridge br_netfilter
modprobe nf_nat
modprobe xt_conntrack
modprobe ip_tables

if test -n "$IS_UNSHARED" ; then
    # make mounts private
    mount --make-rprivate /

    # create loopback interface
    if test -x /sbin/ip ; then 
	ip addr add 127.0.0.1/8 dev lo
	ip addr add ::1/128 dev lo
	ip link set lo up
    else 
	ifconfig lo 127.0.0.1 up
	ifconfig lo add ::1/128
    fi   
fi

# setup cgroups
if test "$BUILD_ROOT" != '/' ; then
    test -d /sys/fs/cgroup || cleanup_and_exit 1 "/sys/fs/cgroup does not exist"

    # make build root a mount point
    mount --rbind --make-private "$BUILD_ROOT" "$BUILD_ROOT"
    mount --make-rprivate "$BUILD_ROOT"

    # mount /sys
    if ! test -e $BUILD_ROOT/sys/block; then
	mkdir -p $BUILD_ROOT/sys
	mount -n -tsysfs sys $BUILD_ROOT/sys
    fi
    # bind mount cgroups
    mount --rbind /sys/fs/cgroup "$BUILD_ROOT/sys/fs/cgroup"
    mount --make-rslave "$BUILD_ROOT/sys/fs/cgroup"
    export DOCKER_RAMDISK=true
fi

# setup mounts
test -e "$BUILD_ROOT/proc/self" || mount -n -tproc none $BUILD_ROOT/proc

echo "Starting container daemon"
chroot $BUILD_ROOT /usr/sbin/containerd --listen unix:///run/containerd/containerd.sock &
CONTAINERD_PID=$!
echo "$CONTAINERD_PID $DOCKERD_PID $WEBSERVER_PID" > $BUILD_ROOT/.startdockerd.pids

echo "Starting docker daemon"
chroot $BUILD_ROOT /usr/bin/dockerd --containerd /run/containerd/containerd.sock --bridge=none --add-runtime oci=/usr/bin/docker-runc &
DOCKERD_PID=$!
echo "$CONTAINERD_PID $DOCKERD_PID $WEBSERVER_PID" > $BUILD_ROOT/.startdockerd.pids

echo "Waiting for docker daemon to complete startup"
for i in 1 2 3 4 5 6 7 8 9 10 ; do
    chroot $BUILD_ROOT docker version >/dev/null 2>&1 && break
    sleep 1
done
if ! chroot $BUILD_ROOT docker version >/dev/null 2>&1 ; then
    cleanup_and_exit 1 "Docker is dead"
fi

if test -n "$WEBSERVER" ; then
    echo "Starting local repository server"
    chroot $BUILD_ROOT bash -c "cd $WEBSERVER && python -m SimpleHTTPServer 80 &"
    WEBSERVER_PID=$!
    echo "$CONTAINERD_PID $DOCKERD_PID $WEBSERVER_PID" > $BUILD_ROOT/.startdockerd.pids
fi

echo "Docker is running"
exit 0