tty: add a helper for setting termios data from kernel side
This basically encapsulates the small bit of locking knowledge needed. While
we are at it make sure we blow up on any more abusers and unsafe misuses of
ioctl for this kind of stuff.
We change the function to return an argument as at some point it needs to
honour the POSIX 'I asked for changes but got none of them' error reporting
corner case.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/tty/tty_ioctl.c b/drivers/tty/tty_ioctl.c
index 0c18899..1a1135d 100644
--- a/drivers/tty/tty_ioctl.c
+++ b/drivers/tty/tty_ioctl.c
@@ -486,7 +486,7 @@
EXPORT_SYMBOL(tty_termios_hw_change);
/**
- * change_termios - update termios values
+ * tty_set_termios - update termios values
* @tty: tty to update
* @new_termios: desired new value
*
@@ -497,7 +497,7 @@
* Locking: termios_mutex
*/
-static void change_termios(struct tty_struct *tty, struct ktermios *new_termios)
+int tty_set_termios(struct tty_struct *tty, struct ktermios *new_termios)
{
struct ktermios old_termios;
struct tty_ldisc *ld;
@@ -553,7 +553,9 @@
tty_ldisc_deref(ld);
}
mutex_unlock(&tty->termios_mutex);
+ return 0;
}
+EXPORT_SYMBOL_GPL(tty_set_termios);
/**
* set_termios - set termios values for a tty
@@ -562,7 +564,7 @@
* @opt: option information
*
* Helper function to prepare termios data and run necessary other
- * functions before using change_termios to do the actual changes.
+ * functions before using tty_set_termios to do the actual changes.
*
* Locking:
* Called functions take ldisc and termios_mutex locks
@@ -620,7 +622,7 @@
return -EINTR;
}
- change_termios(tty, &tmp_termios);
+ tty_set_termios(tty, &tmp_termios);
/* FIXME: Arguably if tmp_termios == tty->termios AND the
actual requested termios was not tmp_termios then we may
@@ -797,7 +799,7 @@
termios.c_ospeed);
#endif
mutex_unlock(&tty->termios_mutex);
- change_termios(tty, &termios);
+ tty_set_termios(tty, &termios);
return 0;
}
#endif
@@ -951,6 +953,8 @@
int ret = 0;
struct ktermios kterm;
+ BUG_ON(file == NULL);
+
if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
tty->driver->subtype == PTY_TYPE_MASTER)
real_tty = tty->link;