Re: [patch 2/2] tty: Add get- ioctls to fetch tty status v2

Jiri Slaby
2012-09-27T17:49:58Z

On 09/27/2012 07:00 PM, Cyrill Gorcunov wrote:
> @@ -199,6 +207,25 @@ static int pty_set_pktmode(struct tty_st
> return 0;
> }
>
> +/* Get the packet mode of a pty */
> +static int pty_get_pktmode(struct tty_struct *tty, int __user *arg)
> +{
> + unsigned long flags;
> + int pktmode;
> +
> + if (tty->driver->subtype != PTY_TYPE_MASTER)
> + return -ENOTTY;

The same as for 1/2^UFixed in v3 ;).

> + spin_lock_irqsave(&tty->ctrl_lock, flags);

I believe the lock is not the right one. It protects ctrl_status in
TIOCPKT, not the packet. And it very seems that packet is unprotected at
all over the code => the lock does not improve anything and is redundant.

> + pktmode = tty->packet;
> + spin_unlock_irqrestore(&tty->ctrl_lock, flags);
> +
> + if (put_user(pktmode, arg))
> + return -EFAULT;
> +
> + return 0;

This can be just
return put_user(pktmode, arg);
Right?

> +}
> +
...
> --- tty.git.orig/include/asm-generic/ioctls.h
> +++ tty.git/include/asm-generic/ioctls.h
> @@ -74,6 +74,9 @@
> #define TCSETXW 0x5435
> #define TIOCSIG _IOW('T', 0x36, int) /* pty: generate signal */
> #define TIOCVHANGUP 0x5437
> +#define TIOCGPKT _IOR('T', 0x38, int) /* Get packet mode state */
> +#define TIOCGPTLCK _IOR('T', 0x39, int) /* Get Pty lock state */
> +#define TIOCGEXCL _IOR('T', 0x40, int) /* Get exclusive mode state */

This is not enough. Some arches do not include this file in their
ioctls.h. You need to update them all.

thanks,
--
js
suse labs