common.sh

#!/bin/sh
#
# This file contains common functions used across multiple scripts
# Use common-update.php script to push update to scripts using them
#

lockfile() { #LOCKFILE_START#
    _LOCKFILE="/var/lock/script-$SCRIPT_NAME.lock"
    _PIDFILE="/var/run/script-$SCRIPT_NAME.pid"
    _FD=100
    _FD_MAX=200

    if [ -n "$2" ]; then
        _LOCKFILE="/var/lock/script-$SCRIPT_NAME-$2.lock"
        _PIDFILE="/var/run/script-$SCRIPT_NAME-$2.lock"
    fi

    [ -n "$3" ] && [ "$3" -eq "$3" ] && _FD="$3" && _FD_MAX="$3"
    [ -n "$4" ] && [ "$4" -eq "$4" ] && _FD_MAX="$4"

    [ ! -d /var/lock ] && mkdir -p /var/lock
    [ ! -d /var/run ] && mkdir -p /var/run

    _LOCKPID=
    [ -f "$_PIDFILE" ] && _LOCKPID="$(cat "$_PIDFILE")"

    case "$1" in
        "lockwait"|"lockfail"|"lockexit")
            while [ -f "/proc/$$/fd/$_FD" ]; do
                echo "File descriptor $_FD is already in use ($(readlink -f "/proc/$$/fd/$_FD"))"
                _FD=$((_FD+1))

                [ "$_FD" -gt "$_FD_MAX" ] && exit 1
            done

            eval exec "$_FD>$_LOCKFILE"

            case "$1" in
                "lockwait")
                    flock -x "$_FD"
                ;;
                "lockfail")
                    flock -nx "$_FD" || return 1
                ;;
                "lockexit")
                    flock -nx "$_FD" || exit 1
                ;;
            esac

            echo $$ > "$_PIDFILE"
            trap 'flock -u $_FD; rm -f "$_LOCKFILE" "$_PIDFILE"; exit $?' INT TERM EXIT
        ;;
        "unlock")
            flock -u "$_FD"
            rm -f "$_LOCKFILE" "$_PIDFILE"
            trap - INT TERM EXIT
        ;;
        "check")
            [ -n "$_LOCKPID" ] && [ -f "/proc/$_LOCKPID/stat" ] && return 0
            return 1
        ;;
        "kill")
            [ -n "$_LOCKPID" ] && [ -f "/proc/$_LOCKPID/stat" ] && kill -9 "$_LOCKPID" && return 0
            return 1
        ;;
    esac
} #LOCKFILE_END#

is_started_by_system() { #ISSTARTEDBYSYSTEM_START#
    _PPID=$PPID
    while true; do
        [ -z "$_PPID" ] && break
        _PPID=$(< "/proc/$_PPID/stat" awk '{print $4}')

        grep -q "cron" "/proc/$_PPID/comm" && return 0
        grep -q "hotplug" "/proc/$_PPID/comm" && return 0
        [ "$_PPID" -gt "1" ] || break
    done

    return 1
} #ISSTARTEDBYSYSTEM_END#