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: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 2 insertions, 24 deletions

diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index ff728d3..fb8ccbf 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -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);
 }