create_logfile

# File lib/logger.rb, line 750
    def create_logfile(filename)
      begin
        logdev = open(filename, (File::WRONLY | File::APPEND | File::CREAT | File::EXCL))
        logdev.flock(File::LOCK_EX)
        logdev.sync = true
        add_log_header(logdev)
        logdev.flock(File::LOCK_UN)
      rescue Errno::EEXIST
        # file is created by another process
        logdev = open_logfile(filename)
        logdev.sync = true
      end
      logdev
    end