[PATCH 10/12] tty: Consolidate noctty checks in tty_open()

From: Peter Hurley
Date: Fri Nov 27 2015 - 21:28:37 EST


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@xxxxxxxxxxxxxxxxxx>
---
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 2a6d40c..1792a20 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -1970,7 +1970,7 @@ 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;

@@ -1980,7 +1980,6 @@ 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
@@ -1991,7 +1990,6 @@ 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;
}
}
@@ -2046,14 +2044,13 @@ 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 &&
--
2.6.3

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