Make sure terminal settings are restored before exiting

When exiting GDB -- whether it's via the "quit" command, via a SIGTERM,
or otherwise -- we should leave the terminal in the state we acquired
it.  To that end, we have to undo any modifications that may have been
made by the TUI (ncurses) or by the CLI (readline).

Tested on x86_64 Debian Stretch.

gdb/ChangeLog:

	* top.c: Include "tui/tui.h".
	(undo_terminal_modifications_before_exit): New static function.
	(quit_force): Use it.

gdb/testsuite/ChangeLog:

	* gdb.base/batch-preserve-term-settings.exp
	(test_terminal_settings_preserved_after_cli_exit): New test.

gdb/ChangeLog

@@ -1,3 +1,9 @@
+2015-07-29  Patrick Palka  <patrick@parcs.ath.cx>
+
+	* top.c: Include "tui/tui.h".
+	(undo_terminal_modifications_before_exit): New static function.
+	(quit_force): Use it.
+
 2015-07-29  Patrick Palka  <patrick@parcs.ath.cx>
 
 	* target.c (terminal_state): Initialize to terminal_is_ours.

gdb/testsuite/ChangeLog

@@ -1,3 +1,8 @@
+2015-07-29  Patrick Palka  <patrick@parcs.ath.cx>
+
+	* gdb.base/batch-preserve-term-settings.exp
+	(test_terminal_settings_preserved_after_cli_exit): New test.
+
 2015-07-29  Patrick Palka  <patrick@parcs.ath.cx>
 
 	* gdb.base/batch-preserve-term-settings.exp: Remove top-level

gdb/testsuite/gdb.base/batch-preserve-term-settings.exp

@@ -176,4 +176,96 @@ proc test_terminal_settings_preserved {} {
     exit_shell
 }
 
-test_terminal_settings_preserved
+# Check that quitting from the CLI via the "quit" command does not leave the
+# terminal in the wrong state.  The GDB commands CMDS are executed before
+# quitting.
+
+proc test_terminal_settings_preserved_after_cli_exit { cmds } {
+    global file_arg
+    global GDB INTERNAL_GDBFLAGS GDBFLAGS
+    global gdb_prompt
+    global shell_prompt_re
+
+    if ![spawn_shell] {
+	return
+    }
+
+    set saved_gdbflags $GDBFLAGS
+
+    set stty_supported [run_stty "stty before" stty_before]
+
+    set test "start gdb"
+    send_gdb "$GDB $INTERNAL_GDBFLAGS $GDBFLAGS [host_info gdb_opts] --args \"$file_arg\"\n"
+    gdb_expect {
+	-re "$gdb_prompt $" {
+	    pass $test
+	}
+	timeout {
+	    fail "$test (timeout)"
+	}
+	eof {
+	    fail "$test (eof)"
+	}
+    }
+
+    foreach cmd $cmds {
+	set test "run command $cmd"
+	send_gdb "$cmd\n"
+	gdb_expect {
+	    -re "$gdb_prompt $" {
+		pass $test
+	    }
+	    timeout {
+		fail "$test (timeout)"
+	    }
+	    eof {
+		fail "$test (eof)"
+	    }
+	}
+    }
+
+    set test "quit gdb"
+    send_gdb "quit\n"
+    gdb_expect {
+	-re "(y or n)" {
+	    send_gdb "y\n"
+	    exp_continue
+	}
+	-re ".*$shell_prompt_re$" {
+	    pass $test
+	}
+	timeout {
+	    fail "$test (timeout)"
+	}
+	eof {
+	    fail "$test (eof)"
+	}
+    }
+
+    set test "terminal settings preserved"
+    if $stty_supported {
+	run_stty "stty after" stty_after
+
+	gdb_assert [string equal $stty_before $stty_after] $test
+    } else {
+	unsupported "$test (no stty)"
+    }
+
+    exit_shell
+}
+
+with_test_prefix "batch run" {
+    test_terminal_settings_preserved
+}
+
+with_test_prefix "cli exit" {
+    test_terminal_settings_preserved_after_cli_exit { }
+}
+
+with_test_prefix "cli exit after start cmd" {
+    test_terminal_settings_preserved_after_cli_exit { "start" }
+}
+
+with_test_prefix "cli exit after run cmd" {
+    test_terminal_settings_preserved_after_cli_exit { "run" }
+}

gdb/top.c

@@ -67,6 +67,10 @@
 #include "tracepoint.h"
 #include "inf-loop.h"
 
+#if defined(TUI)
+# include "tui/tui.h"
+#endif
+
 extern void initialize_all_files (void);
 
 #define PROMPT(X) the_prompts.prompt_stack[the_prompts.top + X].prompt
@@ -1486,6 +1490,21 @@ quit_confirm (void)
   return qr;
 }
 
+/* Prepare to exit GDB cleanly by undoing any changes made to the
+   terminal so that we leave the terminal in the state we acquired it.  */
+
+static void
+undo_terminal_modifications_before_exit (void)
+{
+  target_terminal_ours ();
+#if defined(TUI)
+  tui_disable ();
+#endif
+  if (async_command_editing_p)
+    gdb_disable_readline ();
+}
+
+
 /* Quit without asking for confirmation.  */
 
 void
@@ -1494,6 +1513,8 @@ quit_force (char *args, int from_tty)
   int exit_code = 0;
   struct qt_args qt;
 
+  undo_terminal_modifications_before_exit ();
+
   /* An optional expression may be used to cause gdb to terminate with the 
      value of that expression.  */
   if (args)