1 files changed, 135 insertions, 50 deletions

diff --git a/drivers/char/vt_ioctl.c b/drivers/char/vt_ioctl.c
index 95189f288f8c..35ad94e65d0d 100644
--- a/drivers/char/vt_ioctl.c
+++ b/drivers/char/vt_ioctl.c
@@ -62,6 +62,133 @@ extern struct tty_driver *console_driver;
 static void complete_change_console(struct vc_data *vc);
 
 /*
+ *      User space VT_EVENT handlers
+ */
+
+struct vt_event_wait {
+        struct list_head list;
+        struct vt_event event;
+        int done;
+};
+
+static LIST_HEAD(vt_events);
+static DEFINE_SPINLOCK(vt_event_lock);
+static DECLARE_WAIT_QUEUE_HEAD(vt_event_waitqueue);
+
+/**
+ *      vt_event_post
+ *      @event: the event that occurred
+ *      @old: old console
+ *      @new: new console
+ *
+ *      Post an VT event to interested VT handlers
+ */
+
+void vt_event_post(unsigned int event, unsigned int old, unsigned int new)
+{
+        struct list_head *pos, *head;
+        unsigned long flags;
+        int wake = 0;
+
+        spin_lock_irqsave(&vt_event_lock, flags);
+        head = &vt_events;
+
+        list_for_each(pos, head) {
+                struct vt_event_wait *ve = list_entry(pos,
+                                                struct vt_event_wait, list);
+                if (!(ve->event.event & event))
+                        continue;
+                ve->event.event = event;
+                /* kernel view is consoles 0..n-1, user space view is
+                   console 1..n with 0 meaning current, so we must bias */
+                ve->event.old = old + 1;
+                ve->event.new = new + 1;
+                wake = 1;
+                ve->done = 1;
+        }
+        spin_unlock_irqrestore(&vt_event_lock, flags);
+        if (wake)
+                wake_up_interruptible(&vt_event_waitqueue);
+}
+
+/**
+ *      vt_event_wait           -       wait for an event
+ *      @vw: our event
+ *
+ *      Waits for an event to occur which completes our vt_event_wait
+ *      structure. On return the structure has wv->done set to 1 for success
+ *      or 0 if some event such as a signal ended the wait.
+ */
+
+static void vt_event_wait(struct vt_event_wait *vw)
+{
+        unsigned long flags;
+        /* Prepare the event */
+        INIT_LIST_HEAD(&vw->list);
+        vw->done = 0;
+        /* Queue our event */
+        spin_lock_irqsave(&vt_event_lock, flags);
+        list_add(&vw->list, &vt_events);
+        spin_unlock_irqrestore(&vt_event_lock, flags);
+        /* Wait for it to pass */
+        wait_event_interruptible(vt_event_waitqueue, vw->done);
+        /* Dequeue it */
+        spin_lock_irqsave(&vt_event_lock, flags);
+        list_del(&vw->list);
+        spin_unlock_irqrestore(&vt_event_lock, flags);
+}
+
+/**
+ *      vt_event_wait_ioctl     -       event ioctl handler
+ *      @arg: argument to ioctl
+ *
+ *      Implement the VT_WAITEVENT ioctl using the VT event interface
+ */
+
+static int vt_event_wait_ioctl(struct vt_event __user *event)
+{
+        struct vt_event_wait vw;
+
+        if (copy_from_user(&vw.event, event, sizeof(struct vt_event)))
+                return -EFAULT;
+        /* Highest supported event for now */
+        if (vw.event.event & ~VT_MAX_EVENT)
+                return -EINVAL;
+
+        vt_event_wait(&vw);
+        /* If it occurred report it */
+        if (vw.done) {
+                if (copy_to_user(event, &vw.event, sizeof(struct vt_event)))
+                        return -EFAULT;
+                return 0;
+        }
+        return -EINTR;
+}
+
+/**
+ *      vt_waitactive   -       active console wait
+ *      @event: event code
+ *      @n: new console
+ *
+ *      Helper for event waits. Used to implement the legacy
+ *      event waiting ioctls in terms of events
+ */
+
+int vt_waitactive(int n)
+{
+        struct vt_event_wait vw;
+        do {
+                if (n == fg_console + 1)
+                        break;
+                vw.event.event = VT_EVENT_SWITCH;
+                vt_event_wait(&vw);
+                if (vw.done == 0)
+                        return -EINTR;
+        } while (vw.event.new != n);
+        return 0;
+}
+
+/*
  * these are the valid i/o ports we're allowed to change. they map all the
  * video ports
  */
@@ -360,6 +487,8 @@ do_unimap_ioctl(int cmd, struct unimapdesc __user *user_ud, int perm, struct vc_
         return 0;
 }
 
+
+
 /*
  * We handle the console-specific ioctl's here.  We allow the
  * capability to modify any console, not just the fg_console. 
@@ -851,7 +980,7 @@ int vt_ioctl(struct tty_struct *tty, struct file * file,
                 if (arg == 0 || arg > MAX_NR_CONSOLES)
                         ret = -ENXIO;
                 else
-                        ret = vt_waitactive(arg - 1);
+                        ret = vt_waitactive(arg);
                 break;
 
         /*
@@ -1159,6 +1288,9 @@ int vt_ioctl(struct tty_struct *tty, struct file * file,
                 ret = put_user(vc->vc_hi_font_mask,
                                         (unsigned short __user *)arg);
                 break;
+        case VT_WAITEVENT:
+                ret = vt_event_wait_ioctl((struct vt_event __user *)arg);
+                break;
         default:
                 ret = -ENOIOCTLCMD;
         }
@@ -1170,54 +1302,6 @@ eperm:
         goto out;
 }
 
-/*
- * Sometimes we want to wait until a particular VT has been activated. We
- * do it in a very simple manner. Everybody waits on a single queue and
- * get woken up at once. Those that are satisfied go on with their business,
- * while those not ready go back to sleep. Seems overkill to add a wait
- * to each vt just for this - usually this does nothing!
- */
-static DECLARE_WAIT_QUEUE_HEAD(vt_activate_queue);
-
-/*
- * Sleeps until a vt is activated, or the task is interrupted. Returns
- * 0 if activation, -EINTR if interrupted by a signal handler.
- */
-int vt_waitactive(int vt)
-{
-        int retval;
-        DECLARE_WAITQUEUE(wait, current);
-
-        add_wait_queue(&vt_activate_queue, &wait);
-        for (;;) {
-                retval = 0;
-
-                /*
-                 * Synchronize with redraw_screen(). By acquiring the console
-                 * semaphore we make sure that the console switch is completed
-                 * before we return. If we didn't wait for the semaphore, we
-                 * could return at a point where fg_console has already been
-                 * updated, but the console switch hasn't been completed.
-                 */
-                acquire_console_sem();
-                set_current_state(TASK_INTERRUPTIBLE);
-                if (vt == fg_console) {
-                        release_console_sem();
-                        break;
-                }
-                release_console_sem();
-                retval = -ERESTARTNOHAND;
-                if (signal_pending(current))
-                        break;
-                schedule();
-        }
-        remove_wait_queue(&vt_activate_queue, &wait);
-        __set_current_state(TASK_RUNNING);
-        return retval;
-}
-
-#define vt_wake_waitactive() wake_up(&vt_activate_queue)
-
 void reset_vc(struct vc_data *vc)
 {
         vc->vc_mode = KD_TEXT;
@@ -1262,6 +1346,7 @@ void vc_SAK(struct work_struct *work)
 static void complete_change_console(struct vc_data *vc)
 {
         unsigned char old_vc_mode;
+        int old = fg_console;
 
         last_console = fg_console;
 
@@ -1325,7 +1410,7 @@ static void complete_change_console(struct vc_data *vc)
         /*
          * Wake anyone waiting for their VT to activate
          */
-        vt_wake_waitactive();
+        vt_event_post(VT_EVENT_SWITCH, old, vc->vc_num);
         return;
 }