1 files changed, 95 insertions, 0 deletions
diff --git a/libcons/cons-switch.c b/libcons/cons-switch.c
new file mode 100644
index 00000000..f2b72daf
--- /dev/null
+++ b/libcons/cons-switch.c
@@ -0,0 +1,95 @@
+/* cons-switch.c - Switch to another virtual console.
+   Copyright (C) 2002 Free Software Foundation, Inc.
+   Written by Marcus Brinkmann.
+
+   This file is part of the GNU Hurd.
+
+   The GNU Hurd is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License as
+   published by the Free Software Foundation; either version 2, or (at
+   your option) any later version.
+
+   The GNU Hurd is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111, USA. */
+
+#include <errno.h>
+#include <error.h>
+#include <assert.h>
+
+#include "cons.h"
+
+/* Switch the active console in CONS to ID or the current one plus
+   DELTA.  This will call back into the user code by doing a
+   cons_vcons_activate.  */
+error_t
+cons_switch (cons_t cons, int id, int delta)
+{
+  vcons_t vcons = NULL;
+  vcons_t active;
+
+  if (!id && !delta)
+    return 0;
+
+  mutex_lock (&cons->lock);
+  active = cons->active;
+
+  if (!id && !active)
+    {
+      mutex_unlock (&cons->lock);
+      return EINVAL;
+    }
+
+  if (id)
+    {
+      vcons = cons->vcons_list;
+      while (vcons && vcons->id != id)
+	vcons = vcons->next;
+    }
+  else if (delta > 0)
+    {
+      vcons = cons->active;
+      while (delta-- > 0)
+	{
+	  vcons = vcons->next;
+	  if (!vcons)
+	    vcons = cons->vcons_list;
+	}
+    }
+  else
+    {
+      assert (delta < 0);
+      while (delta++ < 0)
+	{
+	  vcons = vcons->prev;
+	  if (!vcons)
+	    vcons = cons->vcons_last;
+	}
+    }
+
+  if (!vcons)
+    {
+      mutex_unlock (&cons->lock);
+      return ESRCH;
+    }
+
+  if (vcons != active)
+    {
+      error_t err = cons_vcons_activate (vcons);
+      if (err)
+	{
+	  mutex_unlock (&cons->lock);
+	  return err;
+	}
+
+      cons->active = vcons;
+      cons_vcons_refresh (vcons);
+    }
+  mutex_unlock (&cons->lock);
+  return 0;
+}