[PATCH] tty: clarify disassociate_ctty

The code to look at tty_old_pgrp and send SIGHUP and SIGCONT when it is
present only executes when disassociate_ctty is called from do_exit.  Make
this clear by adding an explict on_exit check, and explicitly setting
tty_old_pgrp to 0.

In addition fix the locking by reading tty_old_pgrp under the siglock.

Signed-off-by: Eric W. Biederman <[email protected]>
Cc: Alan Cox <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
This commit is contained in:
Eric W. Biederman 2007-02-12 00:52:52 -08:00 • committed by Linus Torvalds
commit 680a967100

View file

@ -1508,8 +1508,12 @@ void disassociate_ctty(int on_exit)
/* XXX: here we race, there is nothing protecting tty */
if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY)
tty_vhangup(tty);
} else {
pid_t old_pgrp = current->signal->tty_old_pgrp;
} else if (on_exit) {
pid_t old_pgrp;
spin_lock_irq(&current->sighand->siglock);
old_pgrp = current->signal->tty_old_pgrp;
current->signal->tty_old_pgrp = 0;
spin_unlock_irq(&current->sighand->siglock);
if (old_pgrp) {
kill_pg(old_pgrp, SIGHUP, on_exit);
kill_pg(old_pgrp, SIGCONT, on_exit);