[PATCH] remove horrors with irix tty ioctls handling

Existing code in there (get_tty(), etc.) is both severely
racy *and* pointless: ioctls in question have Linux equivalents
and there's no need to play silly buggers in irix_ioctl() -
just need to replace arguments and, in case of TIOCGSID,
deal with API differences - Linux one expects pid_t __user *
while Irix one does unsigned long __user *.  BFD...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 9 insertions, 46 deletions

diff --git a/arch/mips/kernel/irixioctl.c b/arch/mips/kernel/irixioctl.c
index 2bde200d5ad0..b39bdba82e02 100644
--- a/arch/mips/kernel/irixioctl.c
+++ b/arch/mips/kernel/irixioctl.c
@@ -27,33 +27,6 @@ struct irix_termios {
         cc_t c_cc[NCCS];
 };
 
-extern void start_tty(struct tty_struct *tty);
-static struct tty_struct *get_tty(int fd)
-{
-        struct file *filp;
-        struct tty_struct *ttyp = NULL;
-
-        rcu_read_lock();
-        filp = fcheck(fd);
-        if(filp && filp->private_data) {
-                ttyp = (struct tty_struct *) filp->private_data;
-
-                if(ttyp->magic != TTY_MAGIC)
-                        ttyp =NULL;
-        }
-        rcu_read_unlock();
-        return ttyp;
-}
-
-static struct tty_struct *get_real_tty(struct tty_struct *tp)
-{
-        if (tp->driver->type == TTY_DRIVER_TYPE_PTY &&
-           tp->driver->subtype == PTY_TYPE_MASTER)
-                return tp->link;
-        else
-                return tp;
-}
-
 asmlinkage int irix_ioctl(int fd, unsigned long cmd, unsigned long arg)
 {
         struct tty_struct *tp, *rtp;
@@ -146,34 +119,24 @@ asmlinkage int irix_ioctl(int fd, unsigned long cmd, unsigned long arg)
                 error = sys_ioctl(fd, TIOCNOTTY, arg);
                 break;
 
-        case 0x00007416:
+        case 0x00007416: {
+                pid_t pid;
 #ifdef DEBUG_IOCTLS
                 printk("TIOCGSID, %08lx) ", arg);
 #endif
-                tp = get_tty(fd);
-                if(!tp) {
-                        error = -EINVAL;
-                        break;
-                }
-                rtp = get_real_tty(tp);
-#ifdef DEBUG_IOCTLS
-                printk("rtp->session=%d ", rtp->session);
-#endif
-                error = put_user(rtp->session, (unsigned long __user *) arg);
+                old_fs = get_fs(); set_fs(get_ds());
+                error = sys_ioctl(fd, TIOCGSID, (unsigned long)&pid);
+                set_fs(old_fs);
+                if (!error)
+                        error = put_user(pid, (unsigned long __user *) arg);
                 break;
-
+        }
         case 0x746e:
                 /* TIOCSTART, same effect as hitting ^Q */
 #ifdef DEBUG_IOCTLS
                 printk("TIOCSTART, %08lx) ", arg);
 #endif
-                tp = get_tty(fd);
-                if(!tp) {
-                        error = -EINVAL;
-                        break;
-                }
-                rtp = get_real_tty(tp);
-                start_tty(rtp);
+                error = sys_ioctl(fd, TCXONC, TCOON);
                 break;
 
         case 0x20006968: