linux-kernel - [PATCH v2 09/10] tty: Consolidate noctty checks in tty

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Message-Id: <1452402833-8652-10-git-send-email-peter@hurleysoftware.com>
Date:	Sat,  9 Jan 2016 21:13:52 -0800
From:	Peter Hurley <peter@...leysoftware.com>
To:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:	Jiri Slaby <jslaby@...e.cz>, linux-kernel@...r.kernel.org,
	Peter Hurley <peter@...leysoftware.com>
Subject: [PATCH v2 09/10] tty: Consolidate noctty checks in tty_open()

Evaluate the conditions which prevent this tty being the controlling
terminal in one place, just before setting the controlling terminal.

Signed-off-by: Peter Hurley <peter@...leysoftware.com>
---
 drivers/tty/tty_io.c | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 1f8d06f..d223e54 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -1966,7 +1966,7 @@ static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
  *	Locking: tty_mutex protects get_tty_driver
  */
 static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
-		int *noctty, int *index)
+		int *index)
 {
 	struct tty_driver *driver;
 
@@ -1976,7 +1976,6 @@ static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
 		extern struct tty_driver *console_driver;
 		driver = tty_driver_kref_get(console_driver);
 		*index = fg_console;
-		*noctty = 1;
 		break;
 	}
 #endif
@@ -1987,7 +1986,6 @@ static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
 			if (driver) {
 				/* Don't let /dev/console block */
 				filp->f_flags |= O_NONBLOCK;
-				*noctty = 1;
 				break;
 			}
 		}
@@ -2042,14 +2040,13 @@ retry_open:
 	if (retval)
 		return -ENOMEM;
 
-	noctty = filp->f_flags & O_NOCTTY;
 	index  = -1;
 	retval = 0;
 
 	tty = tty_open_current_tty(device, filp);
 	if (!tty) {
 		mutex_lock(&tty_mutex);
-		driver = tty_lookup_driver(device, filp, &noctty, &index);
+		driver = tty_lookup_driver(device, filp, &index);
 		if (IS_ERR(driver)) {
 			retval = PTR_ERR(driver);
 			goto err_unlock;
@@ -2097,10 +2094,6 @@ retry_open:
 	tty_add_file(tty, filp);
 
 	check_tty_count(tty, __func__);
-	if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
-	    tty->driver->subtype == PTY_TYPE_MASTER)
-		noctty = 1;
-
 	tty_debug_hangup(tty, "opening (count=%d)\n", tty->count);
 
 	if (tty->ops->open)
@@ -2133,6 +2126,12 @@ retry_open:
 
 	read_lock(&tasklist_lock);
 	spin_lock_irq(&current->sighand->siglock);
+	noctty = (filp->f_flags & O_NOCTTY) ||
+			device == MKDEV(TTY_MAJOR, 0) ||
+			device == MKDEV(TTYAUX_MAJOR, 1) ||
+			(tty->driver->type == TTY_DRIVER_TYPE_PTY &&
+			 tty->driver->subtype == PTY_TYPE_MASTER);
+
 	if (!noctty &&
 	    current->signal->leader &&
 	    !current->signal->tty &&
-- 
2.7.0