* target.c (target_async_permitted, target_async_permitted_1)

        (set_maintenance_target_async_permitted)
        (show_maintenance_target_async_permitted): New.
        (initialize_targets): Register 'set target-async'.
        * target.h (target_async_permitted): Declare.
        * linux-nat.c (linux_nat_async_enabled)
        (linux_nat_async_permitted, set_maintenance_linux_async_permitted)
        (show_maintenance_linux_async_permitted): Remove.
        (sigchld_handler, linux_nat_is_async_p, linux_nat_can_async_p)
        (get_pending_events, linux_nat_async): Use target_async_permitted.
        (linux_nat_set_async_mode): Remove, moving the only used bits
        into...
        (linux_nat_setup_async): This.
        (_initialize_linux_nat): Do not register 'maint set linux-async'.
        Use linux_nat_setup_async.
        * remote.c (remote_async_permitted, remote_async_permitted_set)
        (set_maintenance_remote_async_permitted)
        (show_maintenance_remote_async_permitted): Remove.
        (remote_open_1, remote_terminal_inferior, remote_can_async_p)
        (remote_is_async_p): Use target_async_permitted.
        (_initialize_remote): Don't register 'main set remote-async'.
        * mi/mi-cmds.c (mi_cmds): Register -list-target-features.
        * mi/mi-cmds.h (mi_cmd_list_target_features): New.
        * mi/mi-main.c (mi_cmd_list_target_features): New.

1 files changed, 39 insertions, 0 deletions

diff --git a/gdb/target.c b/gdb/target.c
index 575415b..e469905 100644
--- a/gdb/target.c
+++ b/gdb/target.c
@@ -3133,6 +3133,35 @@ maintenance_print_target_stack (char *cmd, int from_tty)
     }
 }
 
+/* Controls if async mode is permitted.  */
+int target_async_permitted = 0;
+
+/* The set command writes to this variable.  If the inferior is
+   executing, linux_nat_async_permitted is *not* updated.  */
+static int target_async_permitted_1 = 0;
+
+static void
+set_maintenance_target_async_permitted (char *args, int from_tty,
+					struct cmd_list_element *c)
+{
+  if (target_has_execution)
+    {
+      target_async_permitted_1 = target_async_permitted;
+      error (_("Cannot change this setting while the inferior is running."));
+    }
+
+  target_async_permitted = target_async_permitted_1;
+}
+
+static void
+show_maintenance_target_async_permitted (struct ui_file *file, int from_tty,
+					 struct cmd_list_element *c,
+					 const char *value)
+{
+  fprintf_filtered (file, _("\
+Controlling the inferior in asynchronous mode is %s.\n"), value);
+}
+
 void
 initialize_targets (void)
 {
@@ -3170,5 +3199,15 @@ result in significant performance improvement for remote targets."),
            _("Print the name of each layer of the internal target stack."),
            &maintenanceprintlist);
 
+  add_setshow_boolean_cmd ("target-async", no_class,
+			   &target_async_permitted_1, _("\
+Set whether gdb controls the inferior in asynchronous mode."), _("\
+Show whether gdb controls the inferior in asynchronous mode."), _("\
+Tells gdb whether to control the inferior in asynchronous mode."),
+			   set_maintenance_target_async_permitted,
+			   show_maintenance_target_async_permitted,
+			   &setlist,
+			   &showlist);
+
   target_dcache = dcache_init ();
 }