[PATCH 5/8] tty: refactor TIOCSSERIAL handling

Johan Hovold
2021-04-07T09:52:54Z

Factor out the deprecated serial flags handling and tty-operation check
shared with the compat TIOCSSERIAL handler.

Signed-off-by: Johan Hovold <johan@kernel.org>
---
drivers/tty/tty_io.c | 33 ++++++++++++++++-----------------
1 file changed, 16 insertions(+), 17 deletions(-)

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index e00efd299abd..36e6b28fb80d 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -2624,23 +2624,31 @@ static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
return 0;
}

-static int tty_tiocsserial(struct tty_struct *tty, struct serial_struct __user *ss)
+static int tty_set_serial(struct tty_struct *tty, struct serial_struct *ss)
{
char comm[TASK_COMM_LEN];
- struct serial_struct v;
int flags;

- if (copy_from_user(&v, ss, sizeof(*ss)))
- return -EFAULT;
-
- flags = v.flags & ASYNC_DEPRECATED;
+ flags = ss->flags & ASYNC_DEPRECATED;

if (flags)
pr_warn_ratelimited("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
__func__, get_task_comm(comm, current), flags);
+
if (!tty->ops->set_serial)
return -ENOTTY;
- return tty->ops->set_serial(tty, &v);
+
+ return tty->ops->set_serial(tty, ss);
+}
+
+static int tty_tiocsserial(struct tty_struct *tty, struct serial_struct __user *ss)
+{
+ struct serial_struct v;
+
+ if (copy_from_user(&v, ss, sizeof(*ss)))
+ return -EFAULT;
+
+ return tty_set_serial(tty, &v);
}

static int tty_tiocgserial(struct tty_struct *tty, struct serial_struct __user *ss)
@@ -2838,10 +2846,8 @@ struct serial_struct32 {
static int compat_tty_tiocsserial(struct tty_struct *tty,
struct serial_struct32 __user *ss)
{
- char comm[TASK_COMM_LEN];
struct serial_struct32 v32;
struct serial_struct v;
- int flags;

if (copy_from_user(&v32, ss, sizeof(*ss)))
return -EFAULT;
@@ -2852,14 +2858,7 @@ static int compat_tty_tiocsserial(struct tty_struct *tty,
v.port_high = v32.port_high;
v.iomap_base = 0;

- flags = v.flags & ASYNC_DEPRECATED;
-
- if (flags)
- pr_warn_ratelimited("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
- __func__, get_task_comm(comm, current), flags);
- if (!tty->ops->set_serial)
- return -ENOTTY;
- return tty->ops->set_serial(tty, &v);
+ return tty_set_serial(tty, &v);
}

static int compat_tty_tiocgserial(struct tty_struct *tty,
--
2.26.3