#!/bin/bash
#
# Copyright 2015 Hewlett-Packard Development Company, L.P.
#
# 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.
#

# dib-lint: disable=safe_sudo

if [ "${DIB_DEBUG_TRACE:-0}" -gt 0 ]; then
    set -x
fi
set -eu
set -o pipefail

if [ -f ${TARGET_ROOT}/.extra_settings ] ; then
    . ${TARGET_ROOT}/.extra_settings
fi
ARCH=${ARCH:-x86_64}
if [ $ARCH = amd64 ]; then
    ARCH=x86_64
fi
# Calling elements will need to set DISTRO_NAME and DIB_RELEASE
DIB_YUMCHROOT_EXTRA_ARGS=${DIB_YUMCHROOT_EXTRA_ARGS:-}
YUMCHROOT_TARBALL=$DIB_IMAGE_CACHE/yumchroot-${DISTRO_NAME}-${DIB_RELEASE}-${ARCH}.tar.gz
# TODO Maybe deal with DIB_DISTRIBUTION_MIRROR
http_proxy=${http_proxy:-}
YUM=${YUM:-yum}

WORKING=$(mktemp --tmpdir=${TMP_DIR:-/tmp} -d)
EACTION="rm -r $WORKING"
trap "$EACTION" EXIT

YUM_CACHE=$DIB_IMAGE_CACHE/yum
mkdir -p $YUM_CACHE

# Note, on Debian/Ubuntu, %_dbpath is set in the RPM macros as
# ${HOME}/.rpmdb/ -- this makes sense as RPM isn't the system
# packager.  This path is relative to the "--root" argument
_RPM="rpm --dbpath=/var/lib/rpm"

# install the [fedora|centos]-[release|repo] packages inside the
# chroot, which are needed to bootstrap yum/dnf
#
# note this runs outside the chroot, where we're assuming the platform
# has yum/yumdownloader
function _install_repos {
    local packages
    local rc

    # pre-install the base system packages via rpm.  We previously
    # just left it up to yum to drag these in when we "yum install
    # yum" in the chroot in _install_pkg_manager.  This raised a small
    # problem that inside the empty chroot yum went ahead and did a
    # mkdir for /var/run to put some pid file in, which then messed up
    # the "filesystem" package making /var/run a symlink to /run
    # ... which leads to odd issues with a running system.
    #
    # TODO: these packages still have some small %posttrans stuff that
    # depends on other packages (see rhbz#1306489) ... maybe the idea
    # is that they are only installed in one big transaction with the
    # rest of the system?  but we don't want to use yum to do this
    # (see above) so ...
    packages="basesystem filesystem setup "

    packages+="${DISTRO_NAME}-release "
    # after fedora21, this is split into into a separate -repos
    # package
    if [ $DISTRO_NAME = fedora ]; then
        packages+="${DISTRO_NAME}-repos "
    fi

    # yumdownloader puts repo xml files and such into a directory
    # ${TMPDIR}/yum-$USER-random.  Since we don't need this once the
    # initial download happens, redirect TMPDIR for this call so we
    # can clean it up nicely
    local temp_tmp
    temp_tmp=$(mktemp -d)
    TMPDIR=${temp_tmp} yumdownloader \
        --releasever=$DIB_RELEASE \
        --setopt=reposdir=$TMP_HOOKS_PATH/yum.repos.d \
        --destdir=$WORKING \
        ${packages} && rc=$? || rc=$?
    rm -rf ${temp_tmp}
    if [[ ${rc} != 0 ]]; then
        die "Failed to download initial packages: ${packages}"
    fi

    # --nodeps works around these wanting /bin/sh in some fedora
    # releases, see rhbz#1265873
    sudo $_RPM --root $TARGET_ROOT --nodeps -ivh $WORKING/*rpm
}

# _install_pkg_manager packages...
#
# install the package manager packages.  This is done outside the chroot
# and with yum from the build system.
# TODO: one day build systems will be dnf only, but we don't handle
# that right now
function _install_pkg_manager {
    # Install into the chroot, using the gpg keys from the release
    # rpm's installed in the chroot
    sudo sed -i "s,/etc/pki/rpm-gpg,$TARGET_ROOT/etc/pki/rpm-gpg,g" \
        $TARGET_ROOT/etc/yum.repos.d/*repo

    # See notes on $_RPM variable -- we need to override the
    # $HOME-based dbpath set on debian/ubuntu here.  Unfortunately,
    # yum does not have a way to override rpm macros from the command
    # line.  So we modify the user's ~/.rpmmacros to set %_dbpath back
    # to "/var/lib/rpm" (note, this is taken relative to the
    # --installroot).
    #
    # Also note, we only want this done around this call -- this is
    # the only place we are using yum outside the chroot, and hence
    # picking up the base-system's default rpm macros.  For example,
    # the yumdownloader calls above in _install_repos want to use
    # ~/.rpmdb/ ... there is nothing in the build-system /var/lib/rpm!
    #
    # Another issue we hit is having to set --releasedir here.  yum
    # determines $releasevar based on (more or less) "rpm -q
    # --whatprovides $distroverpkg".  By default, this is
    # "redhat-release" (fedora-release provides redhat-release) but
    # some platforms like CentOS override it in /etc/yum.conf (to
    # centos-release in their case).  You can't override this (see
    # [1]), but setting --releasever works around this.
    #
    # [1] https://bugzilla.redhat.com/show_bug.cgi?id=1287333
    (
        flock -w 1200 9 || die "Can not lock .rpmmacros"
        echo "%_dbpath /var/lib/rpm" >> $HOME/.rpmmacros

        _lang_pack=""

        if [ $DISTRO_NAME = "fedora" -a $DIB_RELEASE -le 23 ]; then
            # _install_langs is a rpm macro that limits the translation
            # files, etc installed by packages.  For Fedora 23 [1], the
            # glibc-common package will obey this to only install the
            # listed locales, keeping things much smaller (we still have
            # to clean up locales manually on centos7).  We install just
            # en_US because people often ssh in with that locale, but
            # leave out everything else.  Note that yum has an option to
            # set this from the command-line [2], but the yum in trusty we
            # are using is too old to have it.  So we set it directly in
            # the macros file
            #
            # [1] http://pkgs.fedoraproject.org/cgit/rpms/glibc.git/commit/glibc.spec?h=f23&id=91764bd9ec690d4b8a886c0a3a104aac12d340d2
            # [2] http://yum.baseurl.org/gitweb?p=yum.git;a=commit;h=26128173b362474456e8f0642073ecb0322ed031
            echo "%_install_langs C:en_US:en_US.UTF-8" >> $HOME/.rpmmacros
        elif [ $DISTRO_NAME = "fedora" -a $DIB_RELEASE -ge 24 ]; then
            # glibc on F24 has split locales into "langpack" packages.
            # Yum doesn't understand the weak-dependencies glibc now
            # uses to get the minimal-langpack and chooses a
            # random(ish) one that satisfies the locale dependency
            # (rhbz#1349258).  Work-around this by explicitly requring
            # the minimal and english (for en_US.UTF-8) pack.
            _lang_pack="glibc-minimal-langpack glibc-langpack-en"
        fi

        sudo -E yum -y \
            --disableexcludes=all \
            --setopt=cachedir=$YUM_CACHE/$ARCH/$DIB_RELEASE \
            --setopt=reposdir=$TARGET_ROOT/etc/yum.repos.d \
            --releasever=$DIB_RELEASE \
            --installroot $TARGET_ROOT \
            install $@ ${_lang_pack} && rc=$? || rc=$?

        # We modified the base system - make sure we clean up always!
        rm $HOME/.rpmmacros.dib.lock
        # sed makes it easy to remove last line, but not last n lines...
        sed -i '$ d' $HOME/.rpmmacros; sed -i '$ d' $HOME/.rpmmacros;
        if [ $rc != 0 ]; then
            die "Initial yum install to chroot failed!  Can not continue."
        fi
    ) 9>$HOME/.rpmmacros.dib.lock

    # Set gpg path back because subsequent actions will take place in
    # the chroot
    sudo sed -i "s,$TARGET_ROOT/etc/pki/rpm-gpg,/etc/pki/rpm-gpg,g" \
        $TARGET_ROOT/etc/yum.repos.d/*repo
}

if [ -n "$DIB_OFFLINE" -o -n "${DIB_YUMCHROOT_USE_CACHE:-}" ] && [ -f $YUMCHROOT_TARBALL ] ; then
    echo $YUMCHROOT_TARBALL found in cache. Using.
    sudo tar -C $TARGET_ROOT --numeric-owner -xzf $YUMCHROOT_TARBALL
else
    # Note this is not usually done for root.d elements (see
    # lib/common-functions:mount_proc_dev_sys) but it's important that
    # we have things like /dev/urandom around inside the chroot for
    # the rpm [pre|post]inst scripts within the packages.
    sudo mkdir -p $TARGET_ROOT/proc $TARGET_ROOT/dev $TARGET_ROOT/sys
    sudo mount -t proc none $TARGET_ROOT/proc
    sudo mount --bind /dev $TARGET_ROOT/dev
    sudo mount --bind /dev/pts $TARGET_ROOT/dev/pts
    sudo mount -t sysfs none $TARGET_ROOT/sys

    # initalize rpmdb
    sudo mkdir -p $TARGET_ROOT/var/lib/rpm
    sudo $_RPM --root $TARGET_ROOT --initdb

    # this makes sure that running yum/dnf in the chroot it can get
    # out to download stuff
    sudo mkdir $TARGET_ROOT/etc
    sudo cp /etc/resolv.conf $TARGET_ROOT/etc/resolv.conf

    # Bind mount the external yum cache inside the chroot.  Same logic
    # as in the yum element to provide for yum caching copied here
    # because the sequencing is wrong otherwise
    sudo mkdir -p $TMP_MOUNT_PATH/tmp/yum
    sudo mount --bind $YUM_CACHE $TMP_MOUNT_PATH/tmp/yum

    _install_repos

    # install dnf for >= f22
    if [ $DIB_RELEASE -ge 22 ]; then
        _install_pkg_manager dnf dnf-plugins-core yum
    else
        _install_pkg_manager yum
    fi

    # we just installed yum/dnf with "outside" tools (yum/rpm) which
    # might have created /var/lib/[yum|rpm] (etc) that are slighlty
    # incompatible.  Refresh everything with the in-chroot tools
    sudo -E chroot $TARGET_ROOT rpm --rebuilddb
    sudo -E chroot $TARGET_ROOT ${YUM} clean all

    # populate the lang reduction macro in the chroot
    echo "%_install_langs C:en_US:en_US.UTF-8" | \
        sudo tee -a $TARGET_ROOT/etc/rpm/macros.langs > /dev/null

    # bootstrap the environment within the chroot; bring in new
    # metadata with an update and install some base packages we need.
    sudo -E chroot $TARGET_ROOT ${YUM} -y update
    sudo -E chroot $TARGET_ROOT ${YUM} -y \
        --setopt=cachedir=/tmp/yum/$ARCH/$DIB_RELEASE \
        install passwd findutils sudo util-linux-ng

    # Put in a dummy /etc/resolv.conf over the temporary one we used
    # to bootstrap.  systemd has a bug/feature [1] that it will assume
    # you want systemd-networkd as the network manager and create a
    # broken symlink to /run/... if the base image doesn't have one.
    # This broken link confuses things like dhclient.
    # [1] https://bugzilla.redhat.com/show_bug.cgi?id=1197204
    echo -e "# This file intentionally left blank\n" | \
        sudo tee $TARGET_ROOT/etc/resolv.conf

    # set the most reliable UTF-8 locale
    echo -e 'LANG="en_US.UTF-8"' | \
        sudo tee $TARGET_ROOT/etc/locale.conf
    # default to UTC
    sudo -E chroot $TARGET_ROOT ln -sf /usr/share/zoneinfo/UTC \
        /etc/localtime

    # cleanup
    # TODO : move this into a exit trap; and reconsider how
    # this integrates with the global exit cleanup path.
    sudo umount $TMP_MOUNT_PATH/tmp/yum
    sudo umount $TARGET_ROOT/proc
    sudo umount $TARGET_ROOT/dev/pts
    sudo umount $TARGET_ROOT/dev
    sudo umount $TARGET_ROOT/sys

    # RPM doesn't know whether files have been changed since install
    # At this point though, we know for certain that we have changed no
    # config files, so anything marked .rpmnew is just a bug.
    for newfile in $(sudo find $TARGET_ROOT -type f -name '*rpmnew') ; do
        sudo mv $newfile $(echo $newfile | sed 's/.rpmnew$//')
    done

    echo Caching result in $YUMCHROOT_TARBALL
    sudo tar --numeric-owner \
        -C $TARGET_ROOT \
        -zcf $YUMCHROOT_TARBALL --exclude='./tmp/*' .
fi

sudo rm -f ${TARGET_ROOT}/.extra_settings