Remove profiler signal handler on shutdown

runtime/vm/signal_handler_android.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"
 #include "vm/simulator.h"
 #include "vm/signal_handler.h"
 #if defined(TARGET_OS_ANDROID)
 
 namespace dart {
@@ skipping 66 matching lines @@
   UNIMPLEMENTED();
 #endif  // TARGET_ARCH_...
   return lr;
 }
 
 
 void SignalHandler::Install(SignalAction action) {
   struct sigaction act;
   memset(&act, 0, sizeof(act));
   act.sa_sigaction = action;
+  sigemptyset(&act.sa_mask);
   act.sa_flags = SA_RESTART | SA_SIGINFO;
-  sigemptyset(&act.sa_mask);
-  // TODO(johnmccutchan): Do we care about restoring the signal handler?
-  struct sigaction old_act;
-  int r = sigaction(SIGPROF, &act, &old_act);
+  int r = sigaction(SIGPROF, &act, NULL);
   ASSERT(r == 0);
 }
 
+
+void SignalHandler::Remove() {
+  // Ignore future SIGPROF signals because by default SIGPROF will terminate
+  // the process and we may have some signals in flight.
+  struct sigaction act;
+  memset(&act, 0, sizeof(act));
+  act.sa_handler = SIG_IGN;
+  sigemptyset(&act.sa_mask);
+  int r = sigaction(SIGPROF, &act, NULL);
+  ASSERT(r == 0);
+}

[siva, 2015/04/07 18:18:07]

The normal protocol is to remember the old action and restore it when the new
action is removed.

The new action handler if it does not have any action for the signal should call
the old action handler if it is not SIG_IGN. In the profiler case this is
probably not needed as you handle all SIGPROF signals.

[Cutch, 2015/04/07 18:35:55]

The default SIGPROF handler terminates the process
(http://man7.org/linux/man-pages/man7/signal.7.html)

+
 
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_ANDROID)