#!/bin/sh /etc/rc.common
# Copyright (C) 2010-2018 OpenWrt.org

# shellcheck disable=SC2034
START=95
# shellcheck disable=SC2034
STOP=10
# shellcheck disable=SC2034
USE_PROCD=1

NAME=mysqld

LOGGER="/usr/bin/logger -p user.err -s -t $NAME --"
[ -x "$LOGGER" ] || LOGGER="echo"

MYSQLD="/usr/bin/$NAME"

pidfile=""

# mysqladmin likes to read /root/.my.cnf which could cause issues.
export HOME="/etc/mysql"

# Safeguard (relative paths, core dumps...)
cd /

mysqld_get_param() {
	"$MYSQLD" --help --verbose | sed -n 's|^'"$1"'[[:blank:]]\+||p'
}

# Send kill signal to MariaDB process
#
# Usage: boolean mysqld_kill signal
mysql_kill() {
	[ -n "$pidfile" ] || pidfile="$(mysqld_get_param pid-file)"
	[ -f "$pidfile" ] || return 1
	pid="$(cat "$pidfile")"
	[ -n "$pid" ] || return 2
	kill "$1" "$pid"
}

# Checks if a server is running and accessible.
#
# Supported modes are 'check_alive' and 'check_dead'.
# Both check for pidfile and whether the specified process is running and is
# indeed mysqld. We could use mysqladmin for the check, but to be able to do
# so, mysqladmin requires access to the database, which sounds like overkill
# and potential security issue.
#
# Usage: boolean mysqld_status [check_alive|check_dead]
mysqld_status() {
	ps_alive=0
	pidfile="$(mysqld_get_param pid-file)"
	if [ -f "$pidfile" ] && mysql_kill -0 2> /dev/null && \
	   [ "$(readlink "/proc/$(cat "$pidfile")/exe")" = "$MYSQLD" ]; then
		ps_alive=1
	fi

	if { [ "$1" = check_alive ] && [ $ps_alive = 1 ]; } || \
		{ [ "$1" = check_dead ] && [ $ps_alive = 0 ]; }
	then
		return 0 # EXIT_SUCCESS
	else
		return 1 # EXIT_FAILURE
	fi
}

start_service() {
	conf=/etc/mysql/my.cnf
	logdir=/var/log/mysql
	version="$(mysqld --version | sed -n 's|.*Ver[[:blank:]]*\([0-9.]*\)-.*|\1|p')"

	# Few basic checks
	if [ ! -x "$MYSQLD" ]; then
		$LOGGER "$MYSQLD is missing"
		exit 1
	fi

	if [ -z "$version" ]; then
		$LOGGER "Can't get MariaDB version, something is seriously wrong"
		exit 1
	fi

	if [ ! -r "$conf" ]; then
		$LOGGER "$conf cannot be read"
		exit 1
	fi

	if mysqld_status check_alive; then
		$LOGGER "server is already running"
		exit 0
	fi

	# Get various config options
	config_load "$NAME"
	config_get my_user general user "mariadb"
	config_get my_group general group "mariadb"
	config_get_bool enabled general enabled 0
	config_get_bool init_db general init 1
	config_get_bool autoupgrade general upgrade 1
	config_get options general options

	# shellcheck disable=SC2154
	if [ "$enabled" -eq 0 ]; then
		$LOGGER "service not enabled in /etc/config/$NAME"
		exit 1
	fi

	datadir="$(mysqld_get_param datadir)"
	tmpdir="$(mysqld_get_param tmpdir)"
	sockdir="$(dirname "$(mysqld_get_param socket)")"

	# Make sure we have a working database in datadir
	if [ ! -f "$datadir/mysql/tables_priv.MAD" ]; then
		args="--force"
		basedir="$(mysqld_get_param basedir)"
		[ -n "$basedir" ] && args="$args --basedir=$basedir"

		# shellcheck disable=SC2154
		if [ "$init_db" -gt 0 ]; then
			# shellcheck disable=SC2154
			mysql_install_db $args --skip-name-resolve --skip-test-db --datadir="$datadir" || exit 1
			echo "$version" > "$datadir"/.version
			chown -Rh "$my_user:$my_group" "$datadir"
		else
			$LOGGER "Cannot detect privileges table. You might need to run"
			$LOGGER "'mysql_install_db \"$args\"'"
			$LOGGER "to initialize the system tables."
			$LOGGER "Then hand it ower to MariaDB user"
			# shellcheck disable=SC2154
			$LOGGER "'chown -Rh \"$my_user:$my_group\" \"$datadir\"'"
		exit 1
		fi
	fi

	# Make sure all required directories exists and have correct rights
	for i in "$logdir" "$sockdir"; do
		opts="-m 0750"
		if ! [ -e "$i" ]; then
			# $sockdir needs to be accessible for clients
			[ "$i" = "$sockdir" ] && opts="-m 0755"
			# shellcheck disable=SC2086
			mkdir -p $opts "$i"
		fi
		# shellcheck disable=SC2154
		[ -d "$i" ] && chown -Rh "$my_user:$my_group" "$i"
	done

	# Migration from old versions
	# shellcheck disable=SC2154
	if [ "$(cat "$datadir"/.version 2> /dev/null)" \!= "$version" ] && [ "$autoupgrade" -gt 0 ]; then
		# Check for correct owner
		local owner="$(stat --format %U:%G "$datadir" 2> /dev/null)"
		if [ -n "$owner" ] && [ "$owner" != "$my_user:$my_group" ]; then
			chown -Rh "$my_user:$my_group" "$datadir"
		fi

		# Start upgrade instance without credentials
		sudo -u "$my_user" mysqld --skip-networking --skip-grant-tables --socket=/tmp/mysql_upgrade.sock &
		PID="$!"
		i=0
		# Wait for upgrade instance of db to start
		while [ "$i" -lt 15 ] && test \! -S /tmp/mysql_upgrade.sock; do
			sleep 1
			i="$((i + 1))"
		done
		[ -S /tmp/mysql_upgrade.sock ] || {
			$LOGGER "Failed to start upgrading instance of MariaDB."
			exit 1
		}
		# Upgrade the database
		mysql_upgrade --upgrade-system-tables --socket=/tmp/mysql_upgrade.sock
		echo "$version" > "$datadir"/.version
		# Stop the upgrade instance
		kill "$PID"
		i=0
		while [ "$i" -lt 60 ] && grep -q mysql "/proc/$PID/cmdline"; do
			sleep 1
			[ "$i" -lt 30 ] || kill "$PID"
			i="$((i + 1))"
		done
		# Use force
		if grep -q mysql "/proc/$PID/cmdline"; then
			kill -9 "$PID"
		fi
	fi

	# Start daemon
	procd_open_instance

	# shellcheck disable=SC2154 disable=SC2086
	procd_set_param command "$MYSQLD" $options
	procd_set_param respawn "${respawn_threshold:-3600}" "${respawn_timeout:-5}" "${respawn_retry:-5}"
	# run as user
	procd_set_param user "$my_user"
	# forward stderr to logd
	procd_set_param stderr 1
	# use HUP to reload
	procd_set_param reload_signal HUP
	# terminate using signals
	procd_set_param term_timeout 60

	procd_close_instance
}