acuppy/daemons

require 'daemons/etc_extension'

class CurrentProcess
  def self.change_privilege(user, group = user)
    puts "Changing process privilege to #{user}:#{group}"

    uid, gid = Process.euid, Process.egid
    target_uid = Etc.getpwnam(user).uid
    target_gid = Etc.getgrnam(group).gid

    if uid != target_uid || gid != target_gid
      Process.initgroups(user, target_gid)
      Process::GID.change_privilege(target_gid)
      Process::UID.change_privilege(target_uid)
    end
  rescue Errno::EPERM => e
    raise "Couldn't change user and group to #{user}:#{group}: #{e}"
  end
end