Commit 2cb5998b authored by Alan Cox's avatar Alan Cox Committed by Linus Torvalds

tty: the vhangup syscall is racy

We now have the infrastructure to sort this out but rather than teaching
the syscall tty lock rules we move the hard work into a tty helper
Signed-off-by: default avatarAlan Cox <alan@redhat.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 216ba023
......@@ -729,6 +729,25 @@ void tty_vhangup(struct tty_struct *tty)
EXPORT_SYMBOL(tty_vhangup);
/**
* tty_vhangup_self - process vhangup for own ctty
*
* Perform a vhangup on the current controlling tty
*/
void tty_vhangup_self(void)
{
struct tty_struct *tty;
mutex_lock(&tty_mutex);
tty = get_current_tty();
if (tty) {
tty_vhangup(tty);
tty_kref_put(tty);
}
mutex_unlock(&tty_mutex);
}
/**
* tty_hung_up_p - was tty hung up
* @filp: file pointer of tty
......
......@@ -1141,8 +1141,7 @@ EXPORT_SYMBOL(sys_close);
asmlinkage long sys_vhangup(void)
{
if (capable(CAP_SYS_TTY_CONFIG)) {
/* XXX: this needs locking */
tty_vhangup(current->signal->tty);
tty_vhangup_self();
return 0;
}
return -EPERM;
......
......@@ -361,6 +361,7 @@ extern int is_ignored(int sig);
extern int tty_signal(int sig, struct tty_struct *tty);
extern void tty_hangup(struct tty_struct *tty);
extern void tty_vhangup(struct tty_struct *tty);
extern void tty_vhangup_self(void);
extern void tty_unhangup(struct file *filp);
extern int tty_hung_up_p(struct file *filp);
extern void do_SAK(struct tty_struct *tty);
......
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