Fix stdin ending up not registered after a Quit

If you press Ctrl-C while GDB is processing breakpoint commands the
TRY/CATCH in inferior_event_handler catches the Quit exception and
prints it, and then if the interpreter was running a foreground
execution command, nothing re-adds stdin back in the event loop,
meaning the debug session ends up busted, because the user can't type
anything...

This was exposed by the new gdb.base/bp-cmds-continue-ctrl-c.exp
testcase added later in the series.

gdb/ChangeLog:
2017-11-16  Pedro Alves  <palves@redhat.com>

	* inf-loop.c (inferior_event_handler): Don't swallow the exception
	if the prompt is blocked.

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 23403b6..766d153 100644 (file)
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,10 @@
 2017-11-16  Pedro Alves  <palves@redhat.com>
 
+       * inf-loop.c (inferior_event_handler): Don't swallow the exception
+       if the prompt is blocked.
+
+2017-11-16  Pedro Alves  <palves@redhat.com>
+
        * breakpoint.c (insert_bp_location): Replace bp_err and
        bp_err_message locals by a gdb_exception local.
 

diff --git a/gdb/inf-loop.c b/gdb/inf-loop.c
index bb9fa01..1d573b9 100644 (file)
--- a/gdb/inf-loop.c
+++ b/gdb/inf-loop.c
@@ -73,7 +73,15 @@ inferior_event_handler (enum inferior_event_type event_type,
            }
          CATCH (e, RETURN_MASK_ALL)
            {
-             exception_print (gdb_stderr, e);
+             /* If the user was running a foreground execution
+                command, then propagate the error so that the prompt
+                can be reenabled.  Otherwise, the user already has
+                the prompt and is typing some unrelated command, so
+                just inform the user and swallow the exception.  */
+             if (current_ui->prompt_state == PROMPT_BLOCKED)
+               throw_exception (e);
+             else
+               exception_print (gdb_stderr, e);
            }
          END_CATCH
        }