Change the ruby process name in top

Question

I would like to change the name of the ruby process that gets displayed in the linux/unix top command. I have tried the

$0=\'miname\'

approach

Answer 1

I know Keltia already posted something very similar, but Linux doesn't have setproctitle(3). Linux has had this functionality in prctl() since version 2.6.9. I used Fiddle/DL since they are included by default with Ruby.

require("fiddle")

def set_process_name_linux(name)
    Fiddle::Function.new(
        Fiddle::Handle["prctl".freeze], [
            Fiddle::TYPE_INT, Fiddle::TYPE_VOIDP,
            Fiddle::TYPE_LONG, Fiddle::TYPE_LONG,
            Fiddle::TYPE_LONG
        ], Fiddle::TYPE_INT
    ).call(15, name, 0, 0, 0)
end

def set_process_name_unknown(name)
    warn("No implementation for this OS.".freeze)
end

def set_process_name(name)
    case RUBY_PLATFORM.split("-".freeze)[1]
    when "linux".freeze
        set_process_name_linux(name)
    else
        set_process_name_unknown(name)
    end
end