Freezing MRI with FFI

freeze.rb

require 'ffi'

module Block
  extend FFI::Library

  ffi_lib FFI::Library::LIBC

  attach_function :sleep, [:uint], :void
end

Thread.new {
  sleep 10

  puts "About to block the process"
  Block.sleep 3600
}

loop do
  puts "#{Time.now}: We are still alive!"
  sleep 1
end

output.txt

2015-03-05 17:54:27 -0800: We are still alive!
2015-03-05 17:54:28 -0800: We are still alive!
2015-03-05 17:54:29 -0800: We are still alive!
2015-03-05 17:54:30 -0800: We are still alive!
2015-03-05 17:54:31 -0800: We are still alive!
2015-03-05 17:54:32 -0800: We are still alive!
2015-03-05 17:54:33 -0800: We are still alive!
2015-03-05 17:54:34 -0800: We are still alive!
2015-03-05 17:54:35 -0800: We are still alive!
2015-03-05 17:54:36 -0800: We are still alive!
About to block the process