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(2) requests supported
by the device that tty refers to, the ioctl(2) request
TIOCNOTTY
is supported.
Detach the current 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 only works
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.
chown(1), mknod(1), ioctl(2), termios(3), console(4), ttyS(4), mingetty(8)
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