[v2,gdb/debuginfod] Ask to cancel further downloads

diff --git a/gdb/debuginfod-support.c b/gdb/debuginfod-support.c
index f1249203da0..da4af4a144b 100644
--- a/gdb/debuginfod-support.c
+++ b/gdb/debuginfod-support.c
@@ -34,6 +34,8 @@  static cmd_list_element *show_debuginfod_prefix_list;
 static const char debuginfod_on[] = "on";
 static const char debuginfod_off[] = "off";
 static const char debuginfod_ask[] = "ask";
+static const char debuginfod_one[] = "one";
+static const char debuginfod_all[] = "all";
 
 static const char *debuginfod_enabled_enum[] =
 {
@@ -43,6 +45,20 @@  static const char *debuginfod_enabled_enum[] =
   nullptr
 };
 
+/* Valid values for set debuginfod cancel command.  */
+
+static const char *debuginfod_cancel_enum[] =
+{
+  debuginfod_one,
+  debuginfod_all,
+  debuginfod_ask,
+  nullptr
+};
+
+/* Value of debuginfod cancellation mode.  */
+
+static const char *debuginfod_cancel = debuginfod_ask;
+
 static const char *debuginfod_enabled =
 #if defined(HAVE_LIBDEBUGINFOD)
   debuginfod_ask;
@@ -88,9 +104,11 @@  debuginfod_exec_query (const unsigned char *build_id,
 struct user_data
 {
   user_data (const char *desc, const char *fname)
-    : desc (desc), fname (fname)
+    : pass_quit_flag (false), inf_had_term (false), desc (desc), fname (fname)
   { }
 
+  bool pass_quit_flag;
+  bool inf_had_term;
   const char * const desc;
   const char * const fname;
   ui_out::progress_update progress;
@@ -148,9 +166,45 @@  progressfn (debuginfod_client *c, long cur, long total)
 
   if (check_quit_flag ())
     {
-      gdb_printf ("Cancelling download of %s %s...\n",
-		  data->desc, styled_fname.c_str ());
-      return 1;
+      /* If a single ^C occurs during downloading, let it propagate to the
+	 target.  If more than one ^C occurs, ask whether to cancel the
+	 current download or interrupt the target.  If the download is
+	 cancelled, the setting of debuginfod_cancel will determine whether
+	 the current download is cancelled or debuginfod is disabled.  */
+      if (!data->pass_quit_flag)
+	data->pass_quit_flag = true;
+      else
+	{
+	  int resp = 1;
+
+	  if (data->inf_had_term)
+	    resp = yquery (_("Cancel the current download?\nIf no, then ^C "
+			     "will be sent to the target process. "));
+	  if (resp)
+	    {
+	      gdb_printf (_("Cancelling download of %s %s...\n"),
+			  data->desc, styled_fname.c_str ());
+	      if (debuginfod_cancel == debuginfod_ask)
+		{
+		  resp = nquery
+		    (_("Cancel further downloading for this session? "));
+		  if (resp)
+		    debuginfod_cancel = debuginfod_all;
+		  else
+		    debuginfod_cancel = debuginfod_one;
+		}
+	      if (debuginfod_cancel == debuginfod_all)
+		{
+		  gdb_printf (_("Debuginfod has been disabled.\nTo re-enable "
+				"use the 'set debuginfod enabled on' "
+				"command.\n"));
+		  debuginfod_enabled = debuginfod_off;
+		}
+
+	      data->pass_quit_flag = false;
+	      return 1;
+	    }
+	}
     }
 
   if (debuginfod_verbose == 0)
@@ -293,6 +347,10 @@  debuginfod_source_query (const unsigned char *build_id,
   user_data data ("source file", srcpath);
 
   debuginfod_set_user_data (c, &data);
+
+  if (!target_terminal::is_ours ())
+    data.inf_had_term = true;
+
   gdb::optional<target_terminal::scoped_restore_terminal_state> term_state;
   if (target_supports_terminal_ours ())
     {
@@ -308,6 +366,10 @@  debuginfod_source_query (const unsigned char *build_id,
   debuginfod_set_user_data (c, nullptr);
   print_outcome (data, fd.get ());
 
+  if (data.pass_quit_flag)
+    set_quit_flag ();
+  if (data.inf_had_term && term_state.has_value ())
+    target_terminal::inferior ();
   if (fd.get () >= 0)
     destname->reset (dname);
 
@@ -334,6 +396,10 @@  debuginfod_debuginfo_query (const unsigned char *build_id,
   user_data data ("separate debug info for", filename);
 
   debuginfod_set_user_data (c, &data);
+
+  if (!target_terminal::is_ours ())
+    data.inf_had_term = true;
+
   gdb::optional<target_terminal::scoped_restore_terminal_state> term_state;
   if (target_supports_terminal_ours ())
     {
@@ -346,6 +412,10 @@  debuginfod_debuginfo_query (const unsigned char *build_id,
   debuginfod_set_user_data (c, nullptr);
   print_outcome (data, fd.get ());
 
+  if (data.pass_quit_flag)
+    set_quit_flag ();
+  if (data.inf_had_term && term_state.has_value ())
+    target_terminal::inferior ();
   if (fd.get () >= 0)
     destname->reset (dname);
 
@@ -372,6 +442,10 @@  debuginfod_exec_query (const unsigned char *build_id,
   user_data data ("executable for", filename);
 
   debuginfod_set_user_data (c, &data);
+
+  if (!target_terminal::is_ours ())
+    data.inf_had_term = true;
+
   gdb::optional<target_terminal::scoped_restore_terminal_state> term_state;
   if (target_supports_terminal_ours ())
     {
@@ -383,6 +457,10 @@  debuginfod_exec_query (const unsigned char *build_id,
   debuginfod_set_user_data (c, nullptr);
   print_outcome (data, fd.get ());
 
+  if (data.pass_quit_flag)
+    set_quit_flag ();
+  if (data.inf_had_term && term_state.has_value ())
+    target_terminal::inferior ();
   if (fd.get () >= 0)
     destname->reset (dname);
 
@@ -423,6 +501,33 @@  show_debuginfod_enabled (ui_file *file, int from_tty, cmd_list_element *cmd,
 		"\"%s\".\n"), debuginfod_enabled);
 }
 
+/* Set callback for "set debuginfod cancel".  */
+
+static void
+set_debuginfod_cancel (const char *value)
+{
+  debuginfod_cancel = value;
+}
+
+/* Get callback for "set debuginfod cancel".  */
+
+static const char *
+get_debuginfod_cancel ()
+{
+  return debuginfod_cancel;
+}
+
+/* Show callback for "set debuginfod cancel".  */
+
+static void
+show_debuginfod_cancel (ui_file *file, int from_tty, cmd_list_element *cmd,
+			const char *value)
+{
+  gdb_printf (file,
+	      _("Debuginfod cancellation mode is currently set to "
+		"\"%s\".\n"), debuginfod_cancel);
+}
+
 /* Set callback for "set debuginfod urls".  */
 
 static void
@@ -503,6 +608,24 @@  source files."),
 			&set_debuginfod_prefix_list,
 			&show_debuginfod_prefix_list);
 
+  add_setshow_enum_cmd ("cancel", class_run, debuginfod_cancel_enum,
+			_("Set cancellation mode for debuginfod."),
+			_("Show cancellation mode for debuginfod."),
+			_("\
+The cancellation mode modifies the behavior of ^C while a file is downloading\
+ from debuginfod.\nWhen set to one, two ^C cancels a single download.\n\
+When set to all, two ^C cancels all further downloads.\n\
+When set to ask, two ^C asks what to do.\nA single ^C during downloading is\
+ passed to the target process being debugged.\nA second ^C during downloading\
+ may raise a prompt asking whether to cancel the download or send ^C to the\
+ target.\nIf the download is to be cancelled, the cancellation mode takes\
+ effect and no ^C is sent to the target."),
+			set_debuginfod_cancel,
+			get_debuginfod_cancel,
+			show_debuginfod_cancel,
+			&set_debuginfod_prefix_list,
+			&show_debuginfod_prefix_list);
+
   /* set/show debuginfod urls */
   add_setshow_string_noescape_cmd ("urls", class_run, _("\
 Set the list of debuginfod server URLs."), _("\
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index bababf3c7ff..246854d229a 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -48270,6 +48270,29 @@  is set to @code{ask} for interactive sessions.
 Display whether @code{debuginfod enabled} is set to @code{on}, @code{off} or
 @code{ask}.
 
+@kindex set debuginfod cancel
+@anchor{set debuginfod cancel}
+@item set debuginfod cancel
+@itemx set debuginfod cancel one
+@cindex debuginfod cancellation mode
+Pressing @code{^C} twice during downloading will cancel the current
+download.
+
+@item set debuginfod cancel all
+Pressing @code{^C} twice during downloading will cancel all further
+downloads.
+
+@item set debuginfod cancel ask
+Pressing @code{^C} twice during a download will prompt the user to
+cancel all further downloads before attempting to perform the next query.
+By default, @code{debuginfod cancel} is set to @code{ask} for interactive
+sessions.
+
+@kindex show debuginfod cancel
+@item show debuginfod cancel
+Display whether @code{debuginfod cancel} is set to @code{one}, @code{all} or
+@code{ask}.
+
 @kindex set debuginfod urls
 @cindex configure debuginfod URLs
 @item set debuginfod urls