#!/bin/bash
# Copyright 2012 Hewlett-Packard Development Company, L.P.
# All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.

function tmpfs_check() {
  local echo_message=${1:-1}
  [ "$DIB_NO_TMPFS" == "0" ] || return 1
  [ -r /proc/meminfo ] || return 1
  total_kB=$(awk '/^MemTotal/ { print $2 }' /proc/meminfo)
  # tmpfs uses by default 50% of the available RAM, so the RAM should be at least
  # the double of the minimum tmpfs size required
  RAM_NEEDED=$(($DIB_MIN_TMPFS * 2))
  [ $total_kB -lt $(($RAM_NEEDED*1024*1024)) ] || return 0
  if [ $echo_message == '1' ]; then
    echo "WARNING: Not enough RAM to use tmpfs for build. Using ${TMP_DIR:-/tmp}. ($total_kB < ${RAM_NEEDED}G)"
  fi
  return 1
}

function mk_build_dir () {
  TMP_BUILD_DIR=$(mktemp -t -d --tmpdir=${TMP_DIR:-/tmp} dib_build.XXXXXXXX)
  TMP_IMAGE_DIR=$(mktemp -t -d --tmpdir=${TMP_DIR:-/tmp} dib_image.XXXXXXXX)
  [ $? -eq 0 ] || die "Failed to create tmp directory"
  export TMP_BUILD_DIR
  if tmpfs_check ; then
    sudo mount -t tmpfs tmpfs $TMP_BUILD_DIR
    sudo mount -t tmpfs tmpfs $TMP_IMAGE_DIR
    sudo chown $(id -u):$(id -g) $TMP_BUILD_DIR $TMP_IMAGE_DIR
  fi
  trap trap_cleanup EXIT
  echo Building in $TMP_BUILD_DIR
  export TMP_IMAGE_PATH=$TMP_IMAGE_DIR/image.raw
  export OUT_IMAGE_PATH=$TMP_IMAGE_PATH
  export TMP_HOOKS_PATH=$TMP_BUILD_DIR/hooks
}

function finish_image () {
    if [ -f $1 -a ${OVERWRITE_OLD_IMAGE:-0} -eq 0 ]; then
      old_image="${1%.*}"-$(date +%Y.%m.%d-%H.%M.%S).${1##*.}
      echo "Old image found. Renaming it to $old_image"
      mv "$1" "$old_image"
      if [ -f "$1.md5" ]; then
        mv "$1.md5" "$old_image.md5"
      fi
      if [ -f "$1.sha256" ]; then
        mv "$1.sha256" "$old_image.sha256"
      fi
    fi

    mv $OUT_IMAGE_PATH $1
    if [ "$DIB_CHECKSUM" == "1" ]; then
      # NOTE(pabelanger): Read image into memory once and generate both checksum
      # files.
      md5sum $1 > $1.md5 & sha256sum $1 > $1.sha256 & wait
    fi
    echo "Image file $1 created..."
}

function save_image () {
    finish_image $1
}

function copy_hooks_not_overwrite () {
    _DIR=$(basename $1)
    test -d $TMP_HOOKS_PATH/$_DIR || mkdir $TMP_HOOKS_PATH/$_DIR
    for _HOOK in $(ls $1); do
      if [ ! -f $TMP_HOOKS_PATH/$_DIR/$_HOOK ]; then
        cp -t $TMP_HOOKS_PATH/$_DIR -a $1/$_HOOK
      else
        echo "There is a duplicated hook in your elements: $_ELEMENT/$_DIR/$_HOOK"
        exit 1
      fi
    done
}

function generate_hooks () {
  mkdir -p $TMP_HOOKS_PATH
  for _ELEMENT in $IMAGE_ELEMENT ; do
    for dir in ${ELEMENTS_PATH//:/ } ; do
      [ -d $dir/$_ELEMENT ] || continue
      for _DIR in $(find $dir/$_ELEMENT -follow -mindepth 1 -maxdepth 1 -type d -not -name tests); do
        copy_hooks_not_overwrite $_DIR
      done
      for _FILE in $(find $dir/$_ELEMENT -follow -maxdepth 1 -type f); do
        cp -t $TMP_HOOKS_PATH -a $_FILE
      done
      break
    done
  done
}

# Call the supplied break-in routine if the named point is listed in the break
# list.
# $1 the break point.
# $2.. what to call if a break is needed
function check_break () {
  if echo "${break:-}" | egrep -e "(,|^)$1(,|$)" -q; then
    echo "Starting debug shell. Exit to resume building." >&2
    echo At stage $1 >&2
    shift
    "$@"
    echo "Resuming" >&2
  fi
}

# Check that a real element has been chosen (prevents foot-guns)
function check_element () {
  [ -d $TMP_HOOKS_PATH ] || generate_hooks
}

# Run a hook, looking for a regex in its stdout, and eval the matched lines.
# $1 is the hook to run
# $2 is the regex to look for
function eval_run_d () {
    local run_output=$(mktemp)
    trap "rm -f $run_output; check_break after-error ${break_cmd:-bash}" ERR
    run_d $1 $run_output
    if grep -q "$2" $run_output; then
        local temp=$(grep "$2" $run_output)
        eval "$temp"
    fi
    rm $run_output
    trap - ERR
}

# Get any process that appears to be running in $TMP_BUILD_DIR
function _get_chroot_processes () {
    # Deselect kernel threads, and use a python script to avoid
    # forking lots and lots of readlink / grep processes on a busy
    # system.
    ps --ppid 2 -p 2 --deselect -o pid= | xargs python -c '
import os
import sys

for pid in sys.argv[2:]:
    try:
        root = os.readlink("/proc/%s/root" % pid)
    except:
        continue
    if sys.argv[1] in root:
        print("%s" % pid)
' $TMP_BUILD_DIR
}


function kill_chroot_processes () {
    local xtrace
    xtrace=$(set +o | grep xtrace)
    set +o xtrace

    local pidname

    if [ -z "${1}" ]; then
        echo "ERROR: no chroot directory specified"
        exit 1
    fi

    for pid in $(_get_chroot_processes); do
        # If there are open files from the chroot, just kill the process using
        # these files.  This is racy, but good enough
        pidname=$(cat $piddir/comm 2>/dev/null || echo "unknown")
        echo "Killing chroot process: '${pidname}($pid)'"
        sudo kill $pid
    done

    $xtrace
}

function cleanup_build_dir () {
    if ! timeout 5  sh -c " while ! sudo rm -rf $TMP_BUILD_DIR/built; do sleep 1; done"; then
        echo "ERROR: unable to cleanly remove $TMP_BUILD_DIR/built"
        exit 1
    fi
    sudo rm -rf $TMP_BUILD_DIR/mnt
    kill_chroot_processes $TMP_BUILD_DIR
    if tmpfs_check 0; then
        # If kill_chroot_processes did not succeed then we have to wait for
        # init to reap the orphaned chroot processes
        if ! timeout 120 sh -c "while ! sudo umount -f $TMP_BUILD_DIR; do sleep 1; done"; then
            echo "ERROR: failed to umount the $TMP_BUILD_DIR tmpfs mount point"
            exit 1
        fi
    fi
    rm -rf --one-file-system $TMP_BUILD_DIR
}

function cleanup_image_dir () {
    kill_chroot_processes $TMP_IMAGE_DIR
    if tmpfs_check 0; then
        if ! timeout 120 sh -c "while ! sudo umount -f $TMP_IMAGE_DIR; do sleep 1; done"; then
            echo "ERROR: failed to umount the $TMP_IMAGE_DIR tmpfs mount point"
            exit 1
        fi
    fi
    rm -rf --one-file-system $TMP_IMAGE_DIR
}

# Run a directory of hooks outside the target (that is, no chrooting).
function run_d() {
    check_element
    check_break before-$1 ${break_cmd:-bash}
    if [ -d ${TMP_HOOKS_PATH}/$1.d ] ; then
        if [ -n "$2" ]; then
            dib-run-parts ${TMP_HOOKS_PATH}/$1.d | tee $2
            if [[ ${PIPESTATUS[0]} != 0 ]]; then
                return 1
            fi
        else
            dib-run-parts ${TMP_HOOKS_PATH}/$1.d
        fi
    fi
    check_break after-$1 bash
}

function detach_loopback() {
    local loopdev=$1

    # Remove the map if it exists
    # If setup on a rhel or derivative the map was created with kpartx not losetup
    # and subsequently needs to be removed.
    loopdev_name=$(echo $loopdev | sed 's/\/dev\///g')

    if sudo dmsetup ls | grep $loopdev_name; then
        mapper_name=$(sudo dmsetup ls | grep $loopdev_name | awk '{ print $1 }')
        sudo dmsetup --noudevsync remove $mapper_name
    fi

    # loopback dev may be tied up a bit by udev events triggered by partition events
    for try in $(seq 10 -1 1) ; do
        if ! sudo losetup $loopdev || sudo losetup -d $loopdev ; then
            return 0
        fi
        echo $loopdev may be busy, sleeping up to $try more seconds...
        sleep 1
    done
    echo Gave up trying to detach $loopdev
    return 1
}

function arg_to_elements() {
  for arg do IMAGE_ELEMENT="$IMAGE_ELEMENT $arg" ; done

  if [ "$SKIP_BASE" != "1" ]; then
    IMAGE_ELEMENT="base $IMAGE_ELEMENT"
  fi
  if [ "$IS_RAMDISK" == "1" ]; then
    IMAGE_ELEMENT="$RAMDISK_ELEMENT $IMAGE_ELEMENT"
  fi
  echo "Building elements: $IMAGE_ELEMENT"

  IMAGE_ELEMENT=$($SCRIPT_HOME/element-info $IMAGE_ELEMENT)
  export IMAGE_ELEMENT

  echo "Expanded element dependencies to: $IMAGE_ELEMENT"
}

function create_base () {
    mkdir $TMP_BUILD_DIR/mnt
    export TMP_MOUNT_PATH=$TMP_BUILD_DIR/mnt
    # Copy data in to the root.
    TARGET_ROOT=$TMP_MOUNT_PATH run_d root
    if [ -z "$(ls $TMP_MOUNT_PATH | grep -v '^lost+found\|tmp$')" ] ; then
        # No root element copied in. Note the test above allows
        # root.d elements to put things in /tmp
        echo "Failed to deploy the root element."
        exit 1
    fi

    # Configure Image
    # Setup resolv.conf so we can chroot to install some packages
    if [ -L $TMP_MOUNT_PATH/etc/resolv.conf ] || [ -f $TMP_MOUNT_PATH/etc/resolv.conf ] ; then
        sudo mv $TMP_MOUNT_PATH/etc/resolv.conf $TMP_MOUNT_PATH/etc/resolv.conf.ORIG
    fi

    # Recreate resolv.conf
    sudo touch $TMP_MOUNT_PATH/etc/resolv.conf
    sudo chmod 777 $TMP_MOUNT_PATH/etc/resolv.conf
    # use system configured resolv.conf if available to support internal proxy resolving
    if [ -e /etc/resolv.conf ]; then
        cat /etc/resolv.conf > $TMP_MOUNT_PATH/etc/resolv.conf
    else
        echo nameserver 8.8.8.8 > $TMP_MOUNT_PATH/etc/resolv.conf
    fi
    mount_proc_dev_sys
}

function mount_proc_dev_sys () {
    # supporting kernel file systems
    sudo mount -t proc none $TMP_MOUNT_PATH/proc
    sudo mount --bind /dev $TMP_MOUNT_PATH/dev
    sudo mount --bind /dev/pts $TMP_MOUNT_PATH/dev/pts
    sudo mount -t sysfs none $TMP_MOUNT_PATH/sys
}

# Recursively unmount directories under a given directory DIR
# usage:
#  unmount_dir DIR
function unmount_dir {
    local dir="$1"
    local real_dir
    local mnts

    if [ ! -d $dir ]; then
        echo "*** $dir is not a directory"
        return 1
    fi

    # get rid of any symlink elements in the incoming path, because
    # /proc/mounts is the real path
    real_dir=$(readlink -e $dir)

    mnts=$(awk '{print $2}' < /proc/mounts | grep "^$real_dir" | sort -r)
    for m in $mnts; do
        echo "Unmount $m"
        sudo umount -fl $m || true
    done
}