#!/bin/sh

install_alpine() {
    rootfs="$1"
    mkdir -p "$rootfs"/etc/apk || return 1
    cp -r ${keys_dir:-/etc/apk/keys} "$rootfs"/etc/apk/
    if [ -n "$repository" ]; then
        echo "$repository" > "$rootfs"/etc/apk/repositories
    else
        cp /etc/apk/repositories "$rootfs"/etc/apk/repositories || return 1
    fi
    ${APK:-apk} add -U --initdb --root $rootfs alpine-base
}

configure_alpine() {
    rootfs="$1"
    echo "Setting up /etc/inittab"
    cat >"$rootfs"/etc/inittab<<EOF
::sysinit:/sbin/rc sysinit
::wait:/sbin/rc default
tty1:12345:respawn:/sbin/getty 38400 tty1
::ctrlaltdel:/sbin/reboot
::shutdown:/sbin/rc shutdown
EOF
    # set up nameserver
    grep nameserver /etc/resolv.conf > "$rootfs/etc/resolv.conf"

    # configure the network using the dhcp
    # note that lxc will set up lo interface
    cat <<EOF > $rootfs/etc/network/interfaces
#auto lo
iface lo inet loopback

auto eth0
iface eth0 inet dhcp
EOF

    # set the hostname
    echo $hostname > $rootfs/etc/hostname

    # missing device nodes
    echo "Setting up device nodes"
    mkdir -p -m 755 "$rootfs/dev/pts"
    mkdir -p -m 1777 "$rootfs/dev/shm"
    mknod -m 666 "$rootfs/dev/full" c 1 7
    mknod -m 666 "$rootfs/dev/random" c 1 8
    mknod -m 666 "$rootfs/dev/urandom" c 1 9
    mknod -m 666 "$rootfs/dev/tty0" c 4 0
    mknod -m 666 "$rootfs/dev/tty1" c 4 1
    mknod -m 666 "$rootfs/dev/tty2" c 4 2
    mknod -m 666 "$rootfs/dev/tty3" c 4 3
    mknod -m 666 "$rootfs/dev/tty4" c 4 4
#    mknod -m 600 "$rootfs/dev/initctl" p
    mknod -m 666 "$rootfs/dev/tty" c 5 0
    mknod -m 666 "$rootfs/dev/console" c 5 1
    mknod -m 666 "$rootfs/dev/ptmx" c 5 2

    # start services
    ln -s /etc/init.d/syslog "$rootfs"/etc/runlevels/default/syslog

    return 0
}

copy_configuration() {
    path=$1
    rootfs=$2
    hostname=$3

    grep -q "^lxc.rootfs" $path/config 2>/dev/null \
        || echo "lxc.rootfs = $rootfs" >> $path/config
    cat <<EOF >> $path/config
lxc.tty = 4
lxc.pts = 1024
lxc.utsname = $hostname

# When using LXC with apparmor, uncomment the next line to run unconfined:
#lxc.aa_profile = unconfined

# network interface
#lxc.network.name = eth0
lxc.network.type = veth
lxc.network.flags = up
# enable for bridging
#lxc.network.link = br0
#lxc.network.ipv4 = n.n.n.n
#lxc.network.ipv4.gateway = auto

# devices
lxc.cgroup.devices.deny = a
# /dev/null and zero
lxc.cgroup.devices.allow = c 1:3 rwm
lxc.cgroup.devices.allow = c 1:5 rwm
# consoles
lxc.cgroup.devices.allow = c 5:1 rwm
lxc.cgroup.devices.allow = c 5:0 rwm
lxc.cgroup.devices.allow = c 4:0 rwm
lxc.cgroup.devices.allow = c 4:1 rwm
# /dev/{,u}random
lxc.cgroup.devices.allow = c 1:9 rwm
lxc.cgroup.devices.allow = c 1:8 rwm
lxc.cgroup.devices.allow = c 136:* rwm
lxc.cgroup.devices.allow = c 5:2 rwm
# rtc
lxc.cgroup.devices.allow = c 254:0 rwm

# mounts point
lxc.mount.entry=proc proc proc nodev,noexec,nosuid 0 0
lxc.mount.entry=run run tmpfs nodev,noexec,nosuid,relatime,size=1m,mode=0755 0 0
lxc.mount.entry=none dev/pts devpts gid=5,mode=620 0 0

EOF

    return 0
}

die() {
    echo "$@" >&2
    exit 1
}

usage() {
    echo "Usage: $(basename $0) [-h|--help] -p|--path <path> -n|--name <name>" >&2
}

usage_err() {
    usage
    exit 1
}

optarg_check() {
    if [ -z "$2" ]; then
        usage_err "option '$1' requires an argument"
    fi
}

default_path=/var/lib/lxc

while [ $# -gt 0 ]; do
        opt="$1"
        shift
        case "$opt" in
        -h|--help)
        usage
        exit 0
        ;;
        -n|--name)
        optarg_check $opt "$1"
        name=$1
        shift
        ;;
        -p|--path)
        optarg_check $opt "$1"
        path=$1
        shift
        ;;
            --)
        break;;
        --*=*)
            # split --myopt=foo=bar into --myopt foo=bar
            set -- ${opt%=*} ${opt#*=} "$@"
        ;;
        -?)
        usage_err "unknown option '$opt'"
        ;;
        -*)
        # split opts -abc into -a -b -c
        set -- $(echo "${opt#-}" | sed 's/\(.\)/ -\1/g') "$@"
        ;;
            *)
        usage
        exit 1
        ;;
        esac
done


[ -z "$name" ] && usage_err

if [ -z "${path}" ]; then
    path="${default_path}/${name}"
fi

rootfs=`awk -F= '$1 ~ /^lxc.rootfs/ { print $2 }' "$path/config" 2>/dev/null`
if [ -z "$rootfs" ]; then
    rootfs="${path}/rootfs"
fi

install_alpine "$rootfs" || die "Failed to install rootfs for $name"
configure_alpine "$rootfs" "$name" || die "Failed to configure $name"
copy_configuration "$path" "$rootfs" "$name"