flockを孫プロセスに保持させてプロセスの終了までロックを無理やり保持する

flock.sh

function flock {
    typeset unlock_flg=0
    while getopts u OPT
    do
        case $OPT in
        u)
            unlock_flg=1
            ;;
        esac
    done
    shift $((OPTIND - 1))
    typeset lockfile=$1
    typeset -i rc
    if [[ $unlock_flg == 1 ]]
    then
        typeset flock_pid=$(ps -eo pid,args | awk -v pid="${$}" -v lockfile="${lockfile}" '$2=="flock" && $3 == pid && $4 == $lockfile{print $1}'
        if [[ -n "${flock_pid}" ]]
        then
            rm -f "${lockfile}"
            kill -9 "${flock_pid}"
            return 0
        else
            return 1
        fi
    fi
    perl -e '
        my $lockfile = $ARGV[0];
        my $ppid = getppid();
        $0 = "flock " . $ppid . " " . $lockfile;
        $SIG{USR1} = sub {
            exit(0);
        };
        $SIG{USR2} = sub {
            exit(1);
        };
        $pid = fork();
        if ($pid) {
            wait();
        } else {
            if (!open(FH, ">>" . $lockfile)) {
                kill "USR2", getppid();
                while (kill(0, getppid())) {
                    sleep(1);
                }
                exit(0);
            }
            if (!flock(FH, 6)) {
                kill "USR2", getppid();
                while (kill(0, getppid())) {
                    sleep(1);
                }
                exit(0);
            }
            kill "USR1", getppid();
            while (kill(0, $ppid)) {
                sleep(1);
            }
            exit(0);
        }
    ' ${lockfile}"; rc=$?
    return "${rc}"
   
}