tty - controlling terminal
The file /dev/tty is a character file with major number 5 and minor
number 0, usually of mode 0666 and owner.group root.tty. It is a synonym
for the controlling terminal of a process, if any.
In addition to the ioctl() requests supported by the device that tty
refers to, the following ioctl() request is supported:
TIOCNOTTY [Toc] [Back]
Detach the current process from its controlling terminal, and
remove it from its current process group, without attaching it
to a new process group (that is, set its process group ID to
zero). This ioctl() call only works on file descriptors connected
to /dev/tty; this 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.
/dev/tty
mknod(1), chown(1), getty(1), termios(2), console(4), ttys(4)
Linux 1992-01-21 TTY(4)
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