* tui/tui-interp.c (tui_is_toplevel): New.

	(tui_init): Set it.
	(tui_allowed_p): New.
	* tui/tui.c (tui_enable): Check if the TUI is allowed before
	enabling it.
	* tui/tui.h (tui_allowed_p): Declare.

3 files changed, 24 insertions, 0 deletions

diff --git a/gdb/tui/tui-interp.c b/gdb/tui/tui-interp.c
index 3bb8246..2a6c3ce 100644
--- a/gdb/tui/tui-interp.c
+++ b/gdb/tui/tui-interp.c
@@ -45,11 +45,16 @@ tui_exit (void)
   tui_disable ();
 }
 
+/* True if TUI is the top-level interpreter.  */
+static int tui_is_toplevel = 0;
+
 /* These implement the TUI interpreter.  */
 
 static void *
 tui_init (int top_level)
 {
+  tui_is_toplevel = top_level;
+
   /* Install exit handler to leave the screen in a good shape.  */
   atexit (tui_exit);
 
@@ -63,6 +68,18 @@ tui_init (int top_level)
   return NULL;
 }
 
+/* True if enabling the TUI is allowed.  Example, if the top level
+   interpreter is MI, enabling curses will certainly lose.  */
+
+int
+tui_allowed_p (void)
+{
+  /* Only if TUI is the top level interpreter.  Also don't try to
+     setup curses (and print funny control characters) if we're not
+     outputting to a terminal.  */
+  return tui_is_toplevel && ui_file_isatty (gdb_stdout);
+}
+
 static int
 tui_resume (void *data)
 {
diff --git a/gdb/tui/tui.c b/gdb/tui/tui.c
index 2ff5c2d..e126d81 100644
--- a/gdb/tui/tui.c
+++ b/gdb/tui/tui.c
@@ -364,6 +364,9 @@ tui_initialize_readline (void)
 void
 tui_enable (void)
 {
+  if (!tui_allowed_p ())
+    error (_("TUI mode not allowed"));
+
   if (tui_active)
     return;
 
diff --git a/gdb/tui/tui.h b/gdb/tui/tui.h
index e9fba98..7ece1b5 100644
--- a/gdb/tui/tui.h
+++ b/gdb/tui/tui.h
@@ -65,6 +65,10 @@ extern int tui_get_command_dimension (unsigned int *width,
    key shortcut.  */
 extern void tui_initialize_readline (void);
 
+/* True if enabling the TUI is allowed.  Example, if the top level
+   interpreter is MI, enabling curses will certainly lose.  */
+extern int tui_allowed_p (void);
+
 /* Enter in the tui mode (curses).  */
 extern void tui_enable (void);