synit/notes/logging.md

from ioctl_tty(2):

   Redirecting console output
       TIOCCONS
              Argument: void

              Redirect output that would have gone to /dev/console or
              /dev/tty0 to the given terminal.  If that was a
              pseudoterminal master, send it to the slave.  In Linux
              before version 2.6.10, anybody can do this as long as the
              output was not redirected yet; since version 2.6.10, only
              a process with the CAP_SYS_ADMIN capability may do this.
              If output was redirected already, then EBUSY is returned,
              but redirection can be stopped by using this ioctl with fd
              pointing at /dev/console or /dev/tty0.