vserver 1.9.3

[linux-2.6.git] / drivers / char / tty_ioctl.c

diff --git a/drivers/char/tty_ioctl.c b/drivers/char/tty_ioctl.c
index ae924c7..830c665 100644 (file)
--- a/drivers/char/tty_ioctl.c
+++ b/drivers/char/tty_ioctl.c
@@ -98,8 +98,17 @@ static void change_termios(struct tty_struct * tty, struct termios * new_termios
 {
        int canon_change;
        struct termios old_termios = *tty->termios;
+       struct tty_ldisc *ld;
+       
+       /*
+        *      Perform the actual termios internal changes under lock.
+        */
+        
+
+       /* FIXME: we need to decide on some locking/ordering semantics
+          for the set_termios notification eventually */
+       down(&tty->termios_sem);
 
-       local_irq_disable(); // FIXME: is this safe?
        *tty->termios = *new_termios;
        unset_locked_termios(tty->termios, &old_termios, tty->termios_locked);
        canon_change = (old_termios.c_lflag ^ tty->termios->c_lflag) & ICANON;
@@ -109,12 +118,13 @@ static void change_termios(struct tty_struct * tty, struct termios * new_termios
                tty->canon_data = 0;
                tty->erasing = 0;
        }
-       local_irq_enable(); // FIXME: is this safe?
+       
+       
        if (canon_change && !L_ICANON(tty) && tty->read_cnt)
                /* Get characters left over from canonical mode. */
                wake_up_interruptible(&tty->read_wait);
 
-       /* see if packet mode change of state */
+       /* See if packet mode change of state. */
 
        if (tty->link && tty->link->packet) {
                int old_flow = ((old_termios.c_iflag & IXON) &&
@@ -132,17 +142,23 @@ static void change_termios(struct tty_struct * tty, struct termios * new_termios
                        wake_up_interruptible(&tty->link->read_wait);
                }
        }
-
+          
        if (tty->driver->set_termios)
                (*tty->driver->set_termios)(tty, &old_termios);
 
-       if (tty->ldisc.set_termios)
-               (*tty->ldisc.set_termios)(tty, &old_termios);
+       ld = tty_ldisc_ref(tty);
+       if (ld != NULL) {
+               if (ld->set_termios)
+                       (ld->set_termios)(tty, &old_termios);
+               tty_ldisc_deref(ld);
+       }
+       up(&tty->termios_sem);
 }
 
 static int set_termios(struct tty_struct * tty, void __user *arg, int opt)
 {
        struct termios tmp_termios;
+       struct tty_ldisc *ld;
        int retval = tty_check_change(tty);
 
        if (retval)
@@ -159,9 +175,14 @@ static int set_termios(struct tty_struct * tty, void __user *arg, int opt)
                        return -EFAULT;
        }
 
-       if ((opt & TERMIOS_FLUSH) && tty->ldisc.flush_buffer)
-               tty->ldisc.flush_buffer(tty);
-
+       ld = tty_ldisc_ref(tty);
+       
+       if (ld != NULL) {
+               if ((opt & TERMIOS_FLUSH) && ld->flush_buffer)
+                       ld->flush_buffer(tty);
+               tty_ldisc_deref(ld);
+       }
+       
        if (opt & TERMIOS_WAIT) {
                tty_wait_until_sent(tty, 0);
                if (signal_pending(current))
@@ -226,11 +247,14 @@ static int get_sgttyb(struct tty_struct * tty, struct sgttyb __user * sgttyb)
 {
        struct sgttyb tmp;
 
+       down(&tty->termios_sem);
        tmp.sg_ispeed = 0;
        tmp.sg_ospeed = 0;
        tmp.sg_erase = tty->termios->c_cc[VERASE];
        tmp.sg_kill = tty->termios->c_cc[VKILL];
        tmp.sg_flags = get_sgflags(tty);
+       up(&tty->termios_sem);
+       
        return copy_to_user(sgttyb, &tmp, sizeof(tmp)) ? -EFAULT : 0;
 }
 
@@ -269,12 +293,16 @@ static int set_sgttyb(struct tty_struct * tty, struct sgttyb __user * sgttyb)
        retval = tty_check_change(tty);
        if (retval)
                return retval;
-       termios =  *tty->termios;
+       
        if (copy_from_user(&tmp, sgttyb, sizeof(tmp)))
                return -EFAULT;
+
+       down(&tty->termios_sem);                
+       termios =  *tty->termios;
        termios.c_cc[VERASE] = tmp.sg_erase;
        termios.c_cc[VKILL] = tmp.sg_kill;
        set_sgflags(&termios, tmp.sg_flags);
+       up(&tty->termios_sem);
        change_termios(tty, &termios);
        return 0;
 }
@@ -365,6 +393,7 @@ int n_tty_ioctl(struct tty_struct * tty, struct file * file,
        struct tty_struct * real_tty;
        void __user *p = (void __user *)arg;
        int retval;
+       struct tty_ldisc *ld;
 
        if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
            tty->driver->subtype == PTY_TYPE_MASTER)
@@ -443,22 +472,26 @@ int n_tty_ioctl(struct tty_struct * tty, struct file * file,
                        retval = tty_check_change(tty);
                        if (retval)
                                return retval;
+                               
+                       ld = tty_ldisc_ref(tty);
                        switch (arg) {
                        case TCIFLUSH:
-                               if (tty->ldisc.flush_buffer)
-                                       tty->ldisc.flush_buffer(tty);
+                               if (ld->flush_buffer)
+                                       ld->flush_buffer(tty);
                                break;
                        case TCIOFLUSH:
-                               if (tty->ldisc.flush_buffer)
-                                       tty->ldisc.flush_buffer(tty);
+                               if (ld->flush_buffer)
+                                       ld->flush_buffer(tty);
                                /* fall through */
                        case TCOFLUSH:
                                if (tty->driver->flush_buffer)
                                        tty->driver->flush_buffer(tty);
                                break;
                        default:
+                               tty_ldisc_deref(ld);
                                return -EINVAL;
                        }
+                       tty_ldisc_deref(ld);
                        return 0;
                case TIOCOUTQ:
                        return put_user(tty->driver->chars_in_buffer ?
@@ -504,9 +537,11 @@ int n_tty_ioctl(struct tty_struct * tty, struct file * file,
                case TIOCSSOFTCAR:
                        if (get_user(arg, (unsigned int __user *) arg))
                                return -EFAULT;
+                       down(&tty->termios_sem);
                        tty->termios->c_cflag =
                                ((tty->termios->c_cflag & ~CLOCAL) |
                                 (arg ? CLOCAL : 0));
+                       up(&tty->termios_sem);
                        return 0;
                default:
                        return -ENOIOCTLCMD;