NAME

       tty - controlling terminal

DESCRIPTION

       The file /dev/tty is a character file with major number 5 and minor number 0, usually with
       mode 0666 and ownership root:tty.  It is a synonym  for  the  controlling  terminal  of  a
       process, if any.

       In  addition  to  the  ioctl(2)  requests  supported by the device that tty refers to, the
       ioctl(2) request TIOCNOTTY is supported.

   TIOCNOTTY
       Detach the calling process from its controlling terminal.

       If the process is the session leader, then SIGHUP and SIGCONT  signals  are  sent  to  the
       foreground  process  group and all processes in the current session lose their controlling
       tty.

       This ioctl(2) call works only on file descriptors connected to /dev/tty.  It  is  used  by
       daemon  processes  when they are invoked by a user at a terminal.  The process attempts to
       open /dev/tty.  If the open succeeds, it  detaches  itself  from  the  terminal  by  using
       TIOCNOTTY,  while  if  the open fails, it is obviously not attached to a terminal and does
       not need to detach itself.

FILES

       /dev/tty

SEE ALSO

       chown(1), mknod(1), ioctl(2), ioctl_console(2), ioctl_tty(2), termios(3), ttyS(4), vcs(4),
       pty(7), agetty(8), mingetty(8)