fix PR gdb/17130

This fixes PR gdb/17130.

The bug is that some code in utils.c was not updated during the target
delegation change:

  if (job_control
      /* If there is no terminal switching for this target, then we can't
         possibly get screwed by the lack of job control.  */
      || current_target.to_terminal_ours == NULL)
    fatal ("Quit");
  else
    fatal ("Quit (expect signal SIGINT when the program is resumed)");

After the delegation change, to_terminal_ours will never be NULL.

I think this bug can be seen before the target delegation change by
enabling target debugging -- this would also cause to_terminal_ours to
be non-NULL.

The fix is to introduce a new target_supports_terminal_ours function,
that properly checks the target stack.  This is not perhaps ideal, but
I think is a reasonable-enough approach, and in keeping with some
other existing code of the same form.

This patch also fixes a similar bug in target_supports_delete_record.

2014-07-18  Tom Tromey  <tromey@redhat.com>

	PR gdb/17130:
	* utils.c (quit): Use target_supports_terminal_ours.
	* target.h (target_supports_terminal_ours): Declare.
	* target.c (target_supports_delete_record): Don't check
	to_delete_record against NULL.
	(target_supports_terminal_ours): New function.

4 files changed, 34 insertions, 2 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index ffecd79..f29d399 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,6 +1,15 @@
 2014-07-18  Tom Tromey  <tromey@redhat.com>
 
 	PR gdb/17130:
+	* utils.c (quit): Use target_supports_terminal_ours.
+	* target.h (target_supports_terminal_ours): Declare.
+	* target.c (target_supports_delete_record): Don't check
+	to_delete_record against NULL.
+	(target_supports_terminal_ours): New function.
+
+2014-07-18  Tom Tromey  <tromey@redhat.com>
+
+	PR gdb/17130:
 	* spu-multiarch.c (spu_region_ok_for_hw_watchpoint)
 	(spu_fetch_registers, spu_store_registers, spu_xfer_partial)
 	(spu_search_memory, spu_mourn_inferior): Simplify delegation.
diff --git a/gdb/target.c b/gdb/target.c
index 07d029a..d77542a 100644
--- a/gdb/target.c
+++ b/gdb/target.c
@@ -499,6 +499,23 @@ target_terminal_inferior (void)
   (*current_target.to_terminal_inferior) (&current_target);
 }
 
+/* See target.h.  */
+
+int
+target_supports_terminal_ours (void)
+{
+  struct target_ops *t;
+
+  for (t = current_target.beneath; t != NULL; t = t->beneath)
+    {
+      if (t->to_terminal_ours != delegate_terminal_ours
+	  && t->to_terminal_ours != tdefault_terminal_ours)
+	return 1;
+    }
+
+  return 0;
+}
+
 static void
 tcomplain (void)
 {
@@ -3457,7 +3474,8 @@ target_supports_delete_record (void)
   struct target_ops *t;
 
   for (t = current_target.beneath; t != NULL; t = t->beneath)
-    if (t->to_delete_record != NULL)
+    if (t->to_delete_record != delegate_delete_record
+	&& t->to_delete_record != tdefault_delete_record)
       return 1;
 
   return 0;
diff --git a/gdb/target.h b/gdb/target.h
index 8c8ce00..35a7d7d 100644
--- a/gdb/target.h
+++ b/gdb/target.h
@@ -1397,6 +1397,11 @@ extern void target_terminal_inferior (void);
 #define target_terminal_ours() \
      (*current_target.to_terminal_ours) (&current_target)
 
+/* Return true if the target stack has a non-default
+  "to_terminal_ours" method.  */
+
+extern int target_supports_terminal_ours (void);
+
 /* Save our terminal settings.
    This is called from TUI after entering or leaving the curses
    mode.  Since curses modifies our terminal this call is here
diff --git a/gdb/utils.c b/gdb/utils.c
index d324227..a9e8196 100644
--- a/gdb/utils.c
+++ b/gdb/utils.c
@@ -1095,7 +1095,7 @@ quit (void)
   if (job_control
       /* If there is no terminal switching for this target, then we can't
          possibly get screwed by the lack of job control.  */
-      || current_target.to_terminal_ours == NULL)
+      || !target_supports_terminal_ours ())
     fatal ("Quit");
   else
     fatal ("Quit (expect signal SIGINT when the program is resumed)");