Commit 2812d9e9 authored by Peter Hurley's avatar Peter Hurley Committed by Greg Kroah-Hartman
Browse files

tty: Combine SIGTTOU/SIGTTIN handling 



The job_control() check in n_tty_read() has nearly identical purpose
and results as tty_check_change(). Both functions' purpose is to
determine if the current task's pgrp is the foreground pgrp for the tty,
and if not, to signal the current pgrp.

Introduce __tty_check_change() which takes the signal to send
and performs the shared operations for job control() and
tty_check_change().

Signed-off-by: default avatarPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 71a5cd8a

drivers/tty/n_tty.c

+2 −24
Original line number Diff line number Diff line
@@ -2138,37 +2138,15 @@ extern ssize_t redirected_tty_write(struct file *, const char __user *, 


static int job_control(struct tty_struct *tty, struct file *file)

{

	struct pid *pgrp;



	/* Job control check -- must be done at start and after

	   every sleep (POSIX.1 7.1.1.4). */

	/* NOTE: not yet done after every sleep pending a thorough

	   check of the logic of this change. -- jlc */

	/* don't stop on /dev/console */

	if (file->f_op->write == redirected_tty_write ||

	    current->signal->tty != tty)

	if (file->f_op->write == redirected_tty_write)

		return 0;



	rcu_read_lock();

	pgrp = task_pgrp(current);



	spin_lock_irq(&tty->ctrl_lock);

	if (!tty->pgrp)

		printk(KERN_ERR "n_tty_read: no tty->pgrp!\n");

	else if (pgrp != tty->pgrp) {

		spin_unlock_irq(&tty->ctrl_lock);

		if (is_ignored(SIGTTIN) || is_current_pgrp_orphaned()) {

			rcu_read_unlock();

			return -EIO;

		}

		kill_pgrp(pgrp, SIGTTIN, 1);

		rcu_read_unlock();

		set_thread_flag(TIF_SIGPENDING);

		return -ERESTARTSYS;

	}

	spin_unlock_irq(&tty->ctrl_lock);

	rcu_read_unlock();

	return 0;

	return __tty_check_change(tty, SIGTTIN);

}

drivers/tty/tty_io.c

+24 −22
Original line number Diff line number Diff line
@@ -390,10 +390,10 @@ EXPORT_SYMBOL_GPL(tty_find_polling_driver); 
 *	Locking: ctrl_lock

 */



int tty_check_change(struct tty_struct *tty)

int __tty_check_change(struct tty_struct *tty, int sig)

{

	unsigned long flags;

	struct pid *pgrp;

	struct pid *pgrp, *tty_pgrp;

	int ret = 0;



	if (current->signal->tty != tty)
@@ -403,33 +403,35 @@ int tty_check_change(struct tty_struct *tty) 
	pgrp = task_pgrp(current);



	spin_lock_irqsave(&tty->ctrl_lock, flags);



	if (!tty->pgrp) {

		printk(KERN_WARNING "tty_check_change: tty->pgrp == NULL!\n");

		goto out_unlock;

	}

	if (pgrp == tty->pgrp)

		goto out_unlock;

	tty_pgrp = tty->pgrp;

	spin_unlock_irqrestore(&tty->ctrl_lock, flags);



	if (is_ignored(SIGTTOU))

		goto out_rcuunlock;

	if (is_current_pgrp_orphaned()) {

	if (tty_pgrp && pgrp != tty->pgrp) {

		if (is_ignored(sig)) {

			if (sig == SIGTTIN)

				ret = -EIO;

		goto out_rcuunlock;

	}

	kill_pgrp(pgrp, SIGTTOU, 1);

	rcu_read_unlock();

		} else if (is_current_pgrp_orphaned())

			ret = -EIO;

		else {

			kill_pgrp(pgrp, sig, 1);

			set_thread_flag(TIF_SIGPENDING);

			ret = -ERESTARTSYS;

	return ret;

out_unlock:

	spin_unlock_irqrestore(&tty->ctrl_lock, flags);

out_rcuunlock:

		}

	}

	rcu_read_unlock();



	if (!tty_pgrp) {

		pr_warn("%s: tty_check_change: sig=%d, tty->pgrp == NULL!\n",

			tty_name(tty), sig);

	}



	return ret;

}



int tty_check_change(struct tty_struct *tty)

{

	return __tty_check_change(tty, SIGTTOU);

}

EXPORT_SYMBOL(tty_check_change);



static ssize_t hung_up_tty_read(struct file *file, char __user *buf,

include/linux/tty.h

+1 −0
Original line number Diff line number Diff line
@@ -423,6 +423,7 @@ extern int tty_paranoia_check(struct tty_struct *tty, struct inode *inode, 
			      const char *routine);

extern const char *tty_name(const struct tty_struct *tty);

extern void tty_wait_until_sent(struct tty_struct *tty, long timeout);

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

extern int tty_check_change(struct tty_struct *tty);

extern void __stop_tty(struct tty_struct *tty);

extern void stop_tty(struct tty_struct *tty);

CRA Git | Maintained and supported by SUSTech CRA and CCSE