#!/bin/bash -e
#
# summary of how this script can be called:
#        * <new-preinst> install
#        * <new-preinst> install <old-version>
#        * <new-preinst> upgrade <old-version>
#        * <old-preinst> abort-upgrade <new-version>
#

# shellcheck source=/dev/null
. /usr/share/debconf/confmodule

# Just kill the invalid insserv.conf.d directory without fallback
if [ -d "/etc/insserv.conf.d/mariadb/" ]
then
  rm -rf "/etc/insserv.conf.d/mariadb/"
fi

if [ -n "$DEBIAN_SCRIPT_DEBUG" ]
then
  set -v -x
  DEBIAN_SCRIPT_TRACE=1
fi
${DEBIAN_SCRIPT_TRACE:+ echo "#42#DEBUG# RUNNING $0 $*" 1>&2 }

export PATH=$PATH:/sbin:/usr/sbin:/bin:/usr/bin
mariadb_datadir=/var/lib/mariadb
legacy_mariadb_datadir=/var/lib/mysql
mariadb_upgradedir=/var/lib/mysql-upgrade

MARIADBD_USERS="root"

# Check if user 'mysql' exists before referring to it in pgrep
# to avoid pgrep erroring on 'invalid user name'
if id mysql >/dev/null 2>&1
then
  MARIADBD_USERS="$MARIADBD_USERS,mysql"
fi

# Try to stop the server in a sane way. If it does not success let the admin
# do it himself. No database directories should be removed while the server
# is running! Another mariadbd in e.g. a different chroot is fine for us.
stop_server() {
  # Return immediately if there are no mysqld processes running on a host
  # (leave containerized processes with the same name in other namespaces)
  # as there is no point in trying to shutdown in that case.
  if ! pgrep -x -u "$MARIADBD_USERS" --nslist pid --ns $$ "mysqld|mariadbd" > /dev/null
  then
    return
  fi

  set +e
  invoke-rc.d mariadb stop
  invoke-rc.d mysql stop # Backwards compatibility
  errno=$?
  set -e

  # systemctl could emit exit code 100=no init script (fresh install)
  if [ "$errno" != 0 ] && [ "$errno" != 100 ]
  then
    echo "Attempt to stop MariaDB/MySQL server returned exitcode $errno" 1>&2
    echo "There is a MariaDB/MySQL server running, but we failed in our attempts to stop it." 1>&2
    echo "Check if there is any server running with 'pgrep -af \"mysqld|mariadbd\"' and" 1>&2
    echo "try to stop it yourself by issuing 'invoke-rc.d mariadb stop'." 1>&2
    db_stop
    exit 1
  fi
}

# Check if the version file mariadb_upgrade_info or mysql_upgrade_info is
# included with the provided data directory. If it is a MariaDB version, then
# return the major version number only (XX.XX). Return empty if this directory
# does not belong to MariaDB.
get_mariadb_upgrade_info_major_version() {
  datadir="$1"

  # Check both mariadb_upgrade_info (higher priority) and mysql_upgrade_info.
  if [ -f "$datadir/mysql_upgrade_info" ]
  then
    read -r full_version < "$datadir/mysql_upgrade_info"
  fi

  if [ -f "$datadir/mariadb_upgrade_info" ]
  then
    read -r full_version < "$datadir/mariadb_upgrade_info"
  fi

  # If version is not empty and contains 'MariaDB', get the version number.
  if [ -n "$full_version" ] && echo "$full_version" | grep -q "MariaDB"
  then
    # The major version number should the first two components of the version
    # string (e.g. 11.8 from 11.8.6).
    echo "$full_version" | awk -F'.' '{print $1"."$2}'
  fi
}

################################ main() ##########################

this_version=11.8
max_upgradeable_version=5.7

# Check for previous mariadb version in the new datadir.
found_version=$(get_mariadb_upgrade_info_major_version "$mariadb_datadir")

# If nothing was found in the new datadir, check the legacy datadir to see if
# it has a MariaDB instance.
if [ -z "$found_version" ] && [ -d "$legacy_mariadb_datadir" ]
then
  found_version=$(get_mariadb_upgrade_info_major_version "$legacy_mariadb_datadir")

  # If a mariadb version was found in the legacy datadir, continue using it.
  if [ -n "$found_version" ]
  then
    mariadb_datadir="$legacy_mariadb_datadir"
  fi
fi

# If an upgrade is detected, proceed with it automatically without
# requiring any user interaction.
#
# However, if the user attempts to downgrade, warn about the incompatibility.
# Downgrade is detected if the flag version is bigger than $this_version
# (e.g. 10.1 > 10.0) or the flag version is smaller than 10.0 but bigger
# than $max_upgradeable_version.
if [ -n "$found_version" ]
then
  echo "$mariadb_datadir: found previous version $found_version"

  if dpkg --compare-versions "$found_version" '>>' "$this_version"
  then
    downgrade_detected=true
  fi

  if dpkg --compare-versions "$found_version" '>>' "$max_upgradeable_version" \
    && dpkg --compare-versions "$found_version" '<<' "10.0"
  then
    downgrade_detected=true
  fi

fi

# Don't abort dpkg if downgrade is detected (as was done previously).
# Instead simply move the old datadir and create a new for this_version.
if [ -n "$downgrade_detected" ]
then
  db_input critical "mariadb-server/old_data_directory_saved" || true
  db_go
  echo "The contents of $mariadb_datadir/ indicates a" 1>&2
  echo "version that cannot automatically be upgraded. Therefore the" 1>&2
  echo "previous data directory will be renamed to $mariadb_datadir-$found_version and" 1>&2
  echo "a new data directory will be initialized at $mariadb_datadir." 1>&2
  echo "Please manually export/import your data (e.g. with mysqldump) if needed." 1>&2
  mv -f "$mariadb_datadir" "$mariadb_datadir-$found_version"
  # Also move away the old debian.cnf file that included credentials that are
  # no longer valid. If none existed, ignore error and let dpkg continue.
  mv -f /etc/mysql/debian.cnf "/etc/mysql/debian.cnf-$found_version" || true
fi

# to be sure
stop_server

# if there's a symlink, let's store where it's pointing, because otherwise
# it's going to be lost in some situations
for dir in DATADIR LOGDIR
do
  checkdir=$(eval echo "$"$dir)
  if [ -L "$checkdir" ]
  then
    # Use mkdir option 'Z' to create with correct SELinux context.
    mkdir -pZ "$mariadb_upgradedir"
    cp -dT "$checkdir" "$mariadb_upgradedir/$dir.link"
  fi
done

# creating mysql home directory
if [ ! -d $mariadb_datadir ] && [ ! -L $mariadb_datadir ]
then
  # Use mkdir option 'Z' to create with correct SELinux context.
  mkdir -Z $mariadb_datadir
fi

# As preset blocksize of GNU df is 1024 then available bytes is $df_available_blocks * 1024
# 4096 blocks is then lower than 4 MB
df_available_blocks="$(LC_ALL=C BLOCKSIZE='' df --output=avail "$mariadb_datadir" | tail -n 1)"
if [ "$df_available_blocks" -lt "4096" ]
then
  echo "ERROR: There's not enough space in $mariadb_datadir/" 1>&2
  db_stop
  exit 1
fi

db_stop

# Automatically added by dh_installinit/13.31
if [ "$1" = "install" ] && [ -n "$2" ] && [ -e "/etc/init.d/mariadb" ] ; then
	chmod +x "/etc/init.d/mariadb" >/dev/null || true
fi
# End automatically added section


# dh_installinit/13.11.3 adds this check but only with 'install', so we need to
# have and extra one to check 'upgrade'. This ensures that upgrades from
# mariadb-server-x.y to mariadb-server (without version suffix) ends up with
# the executable bit set on /etc/init.d/mariadb, which otherwise would end up
# disabled due to the mariadb-server-x.y.postrm being triggered.
#   $1 = upgrade
#   $2 = 1:10.6.11-2
if [ "$1" = "upgrade" ] && [ -n "$2" ] && [ -e "/etc/init.d/mariadb" ]
then
  chmod +x "/etc/init.d/mariadb" >/dev/null || true
fi

# dh_installinit/13.11.3 adds this check but with extra condition that there
# must be a version passed as '$2', but that will always be empty when install
# runs after the unpack that is retriggered for package 'mariadb-server' when
# the old 'mariadb-server-10.6' is purged, so we need to repeat the same check
# here without any expectation for '$2'. This ensures that upgrades from
# mariadb-server-x.y to mariadb-server (without version suffix) ends up with the
# executable bit set on /etc/init.d/mariadb.
if [ "$1" = "install" ] && [ -e "/etc/init.d/mariadb" ]
then
  chmod +x "/etc/init.d/mariadb" >/dev/null || true
fi