pty: If the administrator creates a device for a ptmx slave we should not error

[linux-2.6-omap-h63xx.git] / drivers / char / tty_io.c

diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index f40298e9873a0f274a8563181efa394d0e04bf50..2e96ce0fddc56aacd7027342fc771b7d3d16e82f 100644 (file)
--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -1227,7 +1227,8 @@ static void tty_line_name(struct tty_driver *driver, int index, char *p)
  *     init_dev                -       initialise a tty device
  *     @driver: tty driver we are opening a device on
  *     @idx: device index
- *     @tty: returned tty structure
+ *     @ret_tty: returned tty structure
+ *     @first_ok: ok to open a new device (used by ptmx)
  *
  *     Prepare a tty device. This may not be a "new" clean device but
  *     could also be an active device. The pty drivers require special
@@ -1248,7 +1249,7 @@ static void tty_line_name(struct tty_driver *driver, int index, char *p)
  */
 
 static int init_dev(struct tty_driver *driver, int idx,
-       struct tty_struct **ret_tty)
+       struct tty_struct **ret_tty, int first_ok)
 {
        struct tty_struct *tty, *o_tty;
        struct ktermios *tp, **tp_loc, *o_tp, **o_tp_loc;
@@ -1279,6 +1280,11 @@ static int init_dev(struct tty_driver *driver, int idx,
        }
        if (tty) goto fast_track;
 
+       if (driver->subtype == PTY_TYPE_MASTER &&
+               (driver->flags & TTY_DRIVER_DEVPTS_MEM) && !first_ok) {
+               retval = -EIO;
+               goto end_init;
+       }
        /*
         * First time open is complex, especially for PTY devices.
         * This code guarantees that either everything succeeds and the
@@ -1413,7 +1419,7 @@ static int init_dev(struct tty_driver *driver, int idx,
 
        if (retval)
                goto release_mem_out;
-        goto success;
+       goto success;
 
        /*
         * This fast open can be used if the tty is already open.
@@ -1795,7 +1801,7 @@ static void release_dev(struct file *filp)
 }
 
 /**
- *     tty_open                -       open a tty device
+ *     __tty_open              -       open a tty device
  *     @inode: inode of device file
  *     @filp: file pointer to tty
  *
@@ -1874,7 +1880,7 @@ retry_open:
                return -ENODEV;
        }
 got_driver:
-       retval = init_dev(driver, index, &tty);
+       retval = init_dev(driver, index, &tty, 0);
        mutex_unlock(&tty_mutex);
        if (retval)
                return retval;
@@ -1971,7 +1977,7 @@ static int __ptmx_open(struct inode *inode, struct file *filp)
                return index;
 
        mutex_lock(&tty_mutex);
-       retval = init_dev(ptm_driver, index, &tty);
+       retval = init_dev(ptm_driver, index, &tty, 1);
        mutex_unlock(&tty_mutex);
 
        if (retval)