#!/bin/bash
#
# postgresql-setup - Initialization and upgrade operations for PostgreSQL

# For SELinux we need to use 'runuser' not 'su'
if [ -x /sbin/runuser ]; then
    SU=runuser
else
    SU=su
fi

if test "$(id -u)" -eq 0; then
    cmd=
    for v in PGSETUP_DEBUG PGSETUP_INITDB_OPTIONS PGSETUP_PGUPGRADE_OPTIONS; do
        eval var_content=\$$v
        test -z "$var_content" && continue
        cmd+=$v="$(printf %q "$var_content") "
    done
    cmd+=$(printf %q "$(readlink -f "$0")")
    for arg; do cmd+=" $(printf %q "$arg")" ; done
    # Drop root privileges asap.  It's not recommended to run postgresql-setup
    # script under root nowadays; so we take the liberty to switch to the
    # PostgreSQL admin user (by default 'postgres') without any other option.
    exec $SU -s /bin/sh postgres -c "$cmd"
fi

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

test "$(id -u)" -eq 0 && exit 1

# ensure privacy
umask 0077

: ${RESTORECON=/sbin/restorecon}
test -x $RESTORECON || RESTORECON=:

test x"$PGSETUP_DEBUG" != x && set -x

# PGVERSION is the full package version, e.g., 9.0.2
# Note: the specfile inserts the correct value during package build
PGVERSION=xxxx

# PGMAJORVERSION is the major version, e.g. 9.0
PGMAJORVERSION=xxxx

# PGENGINE is the directory containing the postmaster executable
PGENGINE=xxxx

# PREVMAJORVERSION is the previous major version, e.g., 8.4, for upgrades
PREVMAJORVERSION=xxxx

# PREVPGENGINE is the directory containing the previous postmaster executable
PREVPGENGINE=xxxx

USER=postgres

# Absorb configuration settings from the specified systemd service file,
# or the default "postgresql" service if not specified
SERVICE_NAME="$2"
if [ x"$SERVICE_NAME" = x ]; then
    SERVICE_NAME=postgresql
fi

# Pathname of the RPM distribution README
README_RPM_DIST=xxxx

USAGE_STRING=$"
Usage: $0 {initdb|upgrade} [SERVICE_NAME]

Script is aimed to help sysadmin with basic database cluster administration.

The SERVICE_NAME is used for selection of proper unit configuration file; For
more info and howto/when use this script please look at the docu file
$README_RPM_DIST.  The 'postgresql'
string is used when no SERVICE_NAME is explicitly passed.

Available operation mode:
  initdb        Create a new PostgreSQL database cluster.  This is usually the
                first action you perform after PostgreSQL server installation.
  upgrade       Upgrade PostgreSQL database cluster to be usable with new
                server.  Use this if you upgraded your PostgreSQL server to
                newer major version (currently from $PREVMAJORVERSION \
to $PGMAJORVERSION).

Environment:
  PGSETUP_INITDB_OPTIONS     Options carried by this variable are passed to
                             subsequent call of \`initdb\` binary (see man
                             initdb(1)).  This variable is used also during
                             'upgrade' mode because the new cluster is actually
                             re-initialized from the old one.
  PGSETUP_PGUPGRADE_OPTIONS  Options in this variable are passed next to the
                             subsequent call of \`pg_upgrade\`.  For more info
                             about possible options please look at man
                             pg_upgrade(1).
  PGSETUP_DEBUG              Set to '1' if you want to see debugging output."

# note that these options are useful at least for help2man processing
case "$1" in
    --version)
        echo "postgresql-setup $PGVERSION"
        exit 0
        ;;
    --help|--usage)
        echo "$USAGE_STRING"
        exit 0
        ;;
esac

# this parsing technique fails for PGDATA pathnames containing spaces,
# but there's not much I can do about it given systemctl's output format...
PGDATA=`systemctl show -p Environment "${SERVICE_NAME}.service" |
                sed 's/^Environment=//' | tr ' ' '\n' |
                sed -n 's/^PGDATA=//p' | tail -n 1`
if [ x"$PGDATA" = x ]; then
    echo "failed to find PGDATA setting in ${SERVICE_NAME}.service"
    exit 1
fi

PGPORT=`systemctl show -p Environment "${SERVICE_NAME}.service" |
                sed 's/^Environment=//' | tr ' ' '\n' |
                sed -n 's/^PGPORT=//p' | tail -n 1`
if [ x"$PGPORT" = x ]; then
    echo "failed to find PGPORT setting in ${SERVICE_NAME}.service"
    exit 1
fi

# Log file for initdb
PGLOG=/var/lib/pgsql/initdb.log

# Log file for pg_upgrade
PGUPLOG=/var/lib/pgsql/pgupgrade.log

export PGDATA
export PGPORT

script_result=0

test -w /var/lib/pgsql || {
    echo >&2 $"The /var/lib/pgsql directory has wrong permissions."
    echo >&2 $"Please make sure the directory is writable by postgres."
    exit 1
}

# code shared between initdb and upgrade actions
perform_initdb(){
    if [ ! -e "$PGDATA" ]; then
        mkdir "$PGDATA" || return 1
    fi
    $RESTORECON "$PGDATA"
    test -w "$PGDATA" || die "$PGDATA is not writeable by $USER"

    # Create the initdb log file if needed
    if [ ! -e "$PGLOG" ]; then
        touch "$PGLOG" || return 1
    fi
    $RESTORECON "$PGLOG"
    test -w "$PGLOG" || echo "$PGLOG is not writeable by $USER"

    # Initialize the database
    initdbcmd=(
        "$PGENGINE/initdb" --pgdata="$PGDATA"
                           --auth=ident
    )
    eval "initdbcmd+=( $PGSETUP_INITDB_OPTIONS )"

    "${initdbcmd[@]}" >> "$PGLOG" 2>&1 < /dev/null

    mkdir "$PGDATA/pg_log"
    $RESTORECON "$PGDATA/pg_log"

    if [ -f "$PGDATA/PG_VERSION" ]; then
        return 0
    fi
    return 1
}

initdb(){
    if [ -f "$PGDATA/PG_VERSION" ]; then
        echo $"Data directory is not empty!"
        echo
        script_result=1
    else
        echo -n $"Initializing database ... "
        if perform_initdb; then
            echo $"OK"
        else
            echo $"failed, see $PGLOG"
            script_result=1
        fi
        echo
    fi
}

upgrade(){
    # must see previous version in PG_VERSION
    if [ ! -f "$PGDATA/PG_VERSION" -o \
         x`cat "$PGDATA/PG_VERSION"` != x"$PREVMAJORVERSION" ]
    then
        echo
        echo $"Cannot upgrade because the database in $PGDATA is not of"
        echo $"compatible previous version $PREVMAJORVERSION."
        echo
        exit 1
    fi
    if [ ! -x "$PGENGINE/pg_upgrade" ]; then
        echo
        echo $"Please install the postgresql-upgrade RPM."
        echo
        exit 5
    fi

    # Set up log file for pg_upgrade
    rm -f "$PGUPLOG"
    touch "$PGUPLOG" || exit 1
    $RESTORECON "$PGUPLOG"

    # Move old DB to PGDATAOLD
    PGDATAOLD="${PGDATA}-old"
    rm -rf "$PGDATAOLD"
    mv "$PGDATA" "$PGDATAOLD" || exit 1

    # Create configuration file for upgrade process
    HBA_CONF_BACKUP="$PGDATAOLD/pg_hba.conf.postgresql-setup.`date +%s`"
    HBA_CONF_BACKUP_EXISTS=0

    if [ ! -f $HBA_CONF_BACKUP ]; then
        mv "$PGDATAOLD/pg_hba.conf" "$HBA_CONF_BACKUP"
        HBA_CONF_BACKUP_EXISTS=1

        # For fluent upgrade 'postgres' user should be able to connect
        # to any database without password.  Temporarily, no other type
        # of connection is needed.
        echo "local all postgres ident" > "$PGDATAOLD/pg_hba.conf"
    fi

    echo -n $"Upgrading database: "

    # Create empty new-format database
    if perform_initdb; then
        eval "add_options=( $PGSETUP_PGUPGRADE_OPTIONS )"
        # Do the upgrade
        ( cd # pg_upgrade writes to $PWD
        "$PGENGINE/pg_upgrade" \
                --old-bindir="$PREVPGENGINE" \
                --new-bindir="$PGENGINE" \
                --old-datadir="$PGDATAOLD" \
                --new-datadir="$PGDATA" \
                --link \
                --old-port="$PGPORT" \
                --new-port="$PGPORT" \
                --user=postgres \
                "${add_options[@]}" \
        >> "$PGUPLOG" 2>&1 < /dev/null
        )

        if [ $? -ne 0 ]; then
            # pg_upgrade failed
            script_result=1
        fi
    else
        # initdb failed
        script_result=1
    fi

    # Move back the backed-up pg_hba.conf regardless of the script_result.
    if [ x$HBA_CONF_BACKUP_EXISTS = x1 ]; then
        mv -f "$HBA_CONF_BACKUP" "$PGDATAOLD/pg_hba.conf"
    fi

    if [ $script_result -eq 0 ]; then
        echo $"OK"
        echo
        echo $"The configuration files were replaced by default configuration."
        echo $"The previous configuration and data are stored in folder"
        echo $PGDATAOLD.
    else
        # Clean up after failure
        rm -rf "$PGDATA"
        mv "$PGDATAOLD" "$PGDATA"
        echo $"failed"
    fi
    echo
    echo $"See $PGUPLOG for details."
}

# See how we were called.
case "$1" in
    initdb)
        initdb
        ;;
    upgrade)
        upgrade
        ;;
    *)
        echo >&2 "$USAGE_STRING"
        exit 2
esac

exit $script_result