make -gdb-exit call disconnect_tracing too, and don't lose history if the target errors on "quit"

Gareth mentions in PR gdb/15275:

 "The MI '-gdb-exit' command mi_cmd_gdb_exit() never calls disconnect_tracing()
 and therefore exits correctly."

It should, so to get out of tfind mode, as quit may detach instead of
kill, and we don't want to confuse the memory/register accesses
etc. of the detach process.  So we should push down the disconnect
tracing bits at least to quit_force.  But we can't as is, as that
would swallow the error thrown by answering "no" to:

  Trace is running but will stop on detach; detach anyway? (y or n)

So to address that, we split disconnect_tracing in two.  One part that
does the query, and another part that does the rest, and we make
quit_force call the latter.

Looking at quit_force, it does several things, some of which are a bit
independent of the others.  It first kills/detaches, and then writes
history, and then runs the final cleanups.  It seems better to me to
do each of these things even if the previous thing throws.  E.g., as
is, if something throws while detaching, then we skip writing history.

Tested on x86_64 Fedora 17.

gdb/
2013-04-10  Pedro Alves  <palves@redhat.com>

	* cli/cli-cmds.c (quit_command): Call query_if_trace_running
	instead of disconnect_tracing.
	* infcmd.c (detach_command, disconnect_command): Call
	query_if_trace_running.  Adjust.
	* top.c: Include "tracepoint.h".
	(quit_target): Delete.  Contents moved ...
	(quit_force): ... here.  Wrap each stage of teardown in
	TRY_CATCH.  Call disconnect_tracing before detaching.

gdb/ChangeLog

@@ -1,3 +1,14 @@
+2013-04-10  Pedro Alves  <palves@redhat.com>
+
+	* cli/cli-cmds.c (quit_command): Call query_if_trace_running
+	instead of disconnect_tracing.
+	* infcmd.c (detach_command, disconnect_command): Call
+	query_if_trace_running.  Adjust.
+	* top.c: Include "tracepoint.h".
+	(quit_target): Delete.  Contents moved ...
+	(quit_force): ... here.  Wrap each stage of teardown in
+	TRY_CATCH.  Call disconnect_tracing before detaching.
+
 2013-04-10  Hui Zhu  <hui@codesourcery.com>
 	    Yao Qi  <yao@codesourcery.com>
 

gdb/cli/cli-cmds.c

@@ -322,7 +322,7 @@ quit_command (char *args, int from_tty)
   if (!quit_confirm ())
     error (_("Not confirmed."));
 
-  disconnect_tracing (from_tty);
+  query_if_trace_running (from_tty);
 
   quit_force (args, from_tty);
 }

gdb/infcmd.c

@@ -2721,7 +2721,9 @@ detach_command (char *args, int from_tty)
   if (ptid_equal (inferior_ptid, null_ptid))
     error (_("The program is not being run."));
 
-  disconnect_tracing (from_tty);
+  query_if_trace_running (from_tty);
+
+  disconnect_tracing ();
 
   target_detach (args, from_tty);
 
@@ -2751,7 +2753,8 @@ static void
 disconnect_command (char *args, int from_tty)
 {
   dont_repeat ();		/* Not for the faint of heart.  */
-  disconnect_tracing (from_tty);
+  query_if_trace_running (from_tty);
+  disconnect_tracing ();
   target_disconnect (args, from_tty);
   no_shared_libraries (NULL, from_tty);
   init_thread_list ();

gdb/top.c

@@ -64,6 +64,7 @@
 #include <ctype.h>
 #include "ui-out.h"
 #include "cli-out.h"
+#include "tracepoint.h"
 
 extern void initialize_all_files (void);
 
@@ -1282,29 +1283,6 @@ quit_confirm (void)
   return qr;
 }
 
-/* Helper routine for quit_force that requires error handling.  */
-
-static int
-quit_target (void *arg)
-{
-  struct qt_args *qt = (struct qt_args *)arg;
-
-  /* Kill or detach all inferiors.  */
-  iterate_over_inferiors (kill_or_detach, qt);
-
-  /* Give all pushed targets a chance to do minimal cleanup, and pop
-     them all out.  */
-  pop_all_targets ();
-
-  /* Save the history information if it is appropriate to do so.  */
-  if (write_history_p && history_filename)
-    write_history (history_filename);
-
-  do_final_cleanups (all_cleanups ());    /* Do any final cleanups before
-					     exiting.  */
-  return 0;
-}
-
 /* Quit without asking for confirmation.  */
 
 void
@@ -1312,6 +1290,7 @@ quit_force (char *args, int from_tty)
 {
   int exit_code = 0;
   struct qt_args qt;
+  volatile struct gdb_exception ex;
 
   /* An optional expression may be used to cause gdb to terminate with the 
      value of that expression.  */
@@ -1327,9 +1306,46 @@ quit_force (char *args, int from_tty)
   qt.args = args;
   qt.from_tty = from_tty;
 
+  /* Wrappers to make the code below a bit more readable.  */
+#define DO_TRY \
+  TRY_CATCH (ex, RETURN_MASK_ALL)
+
+#define DO_PRINT_EX \
+  if (ex.reason < 0) \
+    exception_print (gdb_stderr, ex)
+
   /* We want to handle any quit errors and exit regardless.  */
-  catch_errors (quit_target, &qt,
-	        "Quitting: ", RETURN_MASK_ALL);
+
+  /* Get out of tfind mode, and kill or detach all inferiors.  */
+  DO_TRY
+    {
+      disconnect_tracing ();
+      iterate_over_inferiors (kill_or_detach, &qt);
+    }
+  DO_PRINT_EX;
+
+  /* Give all pushed targets a chance to do minimal cleanup, and pop
+     them all out.  */
+  DO_TRY
+    {
+      pop_all_targets ();
+    }
+  DO_PRINT_EX;
+
+  /* Save the history information if it is appropriate to do so.  */
+  DO_TRY
+    {
+      if (write_history_p && history_filename)
+	write_history (history_filename);
+    }
+  DO_PRINT_EX;
+
+  /* Do any final cleanups before exiting.  */
+  DO_TRY
+    {
+      do_final_cleanups (all_cleanups ());
+    }
+  DO_PRINT_EX;
 
   exit (exit_code);
 }

gdb/tracepoint.c

@@ -2204,12 +2204,15 @@ trace_status_mi (int on_stop)
   }
 }
 
-/* This function handles the details of what to do about an ongoing
-   tracing run if the user has asked to detach or otherwise disconnect
-   from the target.  */
+/* Check if a trace run is ongoing.  If so, and FROM_TTY, query the
+   user if she really wants to detach.  */
+
 void
-disconnect_tracing (int from_tty)
+query_if_trace_running (int from_tty)
 {
+  if (!from_tty)
+    return;
+
   /* It can happen that the target that was tracing went away on its
      own, and we didn't notice.  Get a status update, and if the
      current target doesn't even do tracing, then assume it's not
@@ -2222,7 +2225,7 @@ disconnect_tracing (int from_tty)
      just going to disconnect and let the target deal with it,
      according to how it's been instructed previously via
      disconnected-tracing.  */
-  if (current_trace_status ()->running && from_tty)
+  if (current_trace_status ()->running)
     {
       process_tracepoint_on_disconnect ();
 
@@ -2239,7 +2242,15 @@ disconnect_tracing (int from_tty)
 	    error (_("Not confirmed."));
 	}
     }
+}
 
+/* This function handles the details of what to do about an ongoing
+   tracing run if the user has asked to detach or otherwise disconnect
+   from the target.  */
+
+void
+disconnect_tracing (void)
+{
   /* Also we want to be out of tfind mode, otherwise things can get
      confusing upon reconnection.  Just use these calls instead of
      full tfind_1 behavior because we're in the middle of detaching,

gdb/tracepoint.h

@@ -387,7 +387,8 @@ extern struct tracepoint *create_tracepoint_from_upload (struct uploaded_tp *utp
 extern void merge_uploaded_tracepoints (struct uploaded_tp **utpp);
 extern void merge_uploaded_trace_state_variables (struct uploaded_tsv **utsvp);
 
-extern void disconnect_tracing (int from_tty);
+extern void query_if_trace_running (int from_tty);
+extern void disconnect_tracing (void);
 
 extern void start_tracing (char *notes);
 extern void stop_tracing (char *notes);