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

drivers/char/tty_io.c

+19 −0
Original line number Original line Diff line number Diff line
@@ -729,6 +729,25 @@ void tty_vhangup(struct tty_struct *tty) 




EXPORT_SYMBOL(tty_vhangup);

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

 *	tty_hung_up_p		-	was tty hung up

 *	@filp: file pointer of tty

 *	@filp: file pointer of tty

fs/open.c

+1 −2
Original line number Original line Diff line number Diff line
@@ -1141,8 +1141,7 @@ EXPORT_SYMBOL(sys_close); 
asmlinkage long sys_vhangup(void)

asmlinkage long sys_vhangup(void)

{

{

	if (capable(CAP_SYS_TTY_CONFIG)) {

	if (capable(CAP_SYS_TTY_CONFIG)) {

		/* XXX: this needs locking */

		tty_vhangup_self();

		tty_vhangup(current->signal->tty);

		return 0;

		return 0;

	}

	}

	return -EPERM;

	return -EPERM;

include/linux/tty.h

+1 −0
Original line number Original line Diff line number Diff line
@@ -361,6 +361,7 @@ extern int is_ignored(int sig); 
extern int tty_signal(int sig, struct tty_struct *tty);

extern int tty_signal(int sig, struct tty_struct *tty);

extern void tty_hangup(struct tty_struct *tty);

extern void tty_hangup(struct tty_struct *tty);

extern void tty_vhangup(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 void tty_unhangup(struct file *filp);

extern int tty_hung_up_p(struct file *filp);

extern int tty_hung_up_p(struct file *filp);

extern void do_SAK(struct tty_struct *tty);

extern void do_SAK(struct tty_struct *tty);