[dart:io] Adds a finalizer to _NativeSocket to avoid socket leaks

runtime/bin/eventhandler_linux.cc

 // Copyright (c) 2012, 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.
 
 #if !defined(DART_IO_DISABLED)
 
 #include "platform/globals.h"
 #if defined(HOST_OS_LINUX)
 
 #include "bin/eventhandler.h"
@@ skipping 204 matching lines @@
         int64_t millis = timeout_queue_.CurrentTimeout();
         it.it_value.tv_sec = millis / 1000;
         it.it_value.tv_nsec = (millis % 1000) * 1000000;
       }
       VOID_NO_RETRY_EXPECTED(
           timerfd_settime(timer_fd_, TFD_TIMER_ABSTIME, &it, NULL));
     } else if (msg[i].id == kShutdownId) {
       shutdown_ = true;
     } else {
       ASSERT((msg[i].data & COMMAND_MASK) != 0);
-
+      Socket* socket = reinterpret_cast<Socket*>(msg[i].id);
+      RefCntReleaseScope<Socket> rs(socket);
+      if (socket->fd() == -1) {
+        continue;
+      }
       DescriptorInfo* di =
-          GetDescriptorInfo(msg[i].id, IS_LISTENING_SOCKET(msg[i].data));
+          GetDescriptorInfo(socket->fd(), IS_LISTENING_SOCKET(msg[i].data));
       if (IS_COMMAND(msg[i].data, kShutdownReadCommand)) {
         ASSERT(!di->IsListeningSocket());
         // Close the socket for reading.
         VOID_NO_RETRY_EXPECTED(shutdown(di->fd(), SHUT_RD));
       } else if (IS_COMMAND(msg[i].data, kShutdownWriteCommand)) {
         ASSERT(!di->IsListeningSocket());
         // Close the socket for writing.
         VOID_NO_RETRY_EXPECTED(shutdown(di->fd(), SHUT_WR));
       } else if (IS_COMMAND(msg[i].data, kCloseCommand)) {
         // Close the socket and free system resources and move on to next
         // message.
         intptr_t old_mask = di->Mask();
         Dart_Port port = msg[i].dart_port;
         di->RemovePort(port);
         intptr_t new_mask = di->Mask();
         UpdateEpollInstance(old_mask, di);
 
         intptr_t fd = di->fd();
         if (di->IsListeningSocket()) {
           // We only close the socket file descriptor from the operating
           // system if there are no other dart socket objects which
           // are listening on the same (address, port) combination.
           ListeningSocketRegistry* registry =
               ListeningSocketRegistry::Instance();
 
           MutexLocker locker(registry->mutex());
 
-          if (registry->CloseSafe(fd)) {
+          if (registry->CloseSafe(socket)) {
             ASSERT(new_mask == 0);
             socket_map_.Remove(GetHashmapKeyFromFd(fd),
                                GetHashmapHashFromFd(fd));
             di->Close();
             delete di;
+            socket->SetClosedFd();
           }
         } else {
           ASSERT(new_mask == 0);
           socket_map_.Remove(GetHashmapKeyFromFd(fd), GetHashmapHashFromFd(fd));
           di->Close();
           delete di;
+          socket->SetClosedFd();
         }
-
         DartUtils::PostInt32(port, 1 << kDestroyedEvent);
       } else if (IS_COMMAND(msg[i].data, kReturnTokenCommand)) {
         int count = TOKEN_COUNT(msg[i].data);
         intptr_t old_mask = di->Mask();
         di->ReturnTokens(msg[i].dart_port, count);
         UpdateEpollInstance(old_mask, di);
       } else if (IS_COMMAND(msg[i].data, kSetEventMaskCommand)) {
         // `events` can only have kInEvent/kOutEvent flags set.
         intptr_t events = msg[i].data & EVENT_MASK;
         ASSERT(0 == (events & ~(1 << kInEvent | 1 << kOutEvent)));
@@ skipping 116 matching lines @@
         epoll_wait(handler_impl->epoll_fd_, events, kMaxEvents, -1));
     ASSERT(EAGAIN == EWOULDBLOCK);
     if (result <= 0) {
       if (errno != EWOULDBLOCK) {
         perror("Poll failed");
       }
     } else {
       handler_impl->HandleEvents(events, result);
     }
   }
+  DEBUG_ASSERT(ReferenceCounted<Socket>::instances() == 0);
   handler->NotifyShutdownDone();
 }
 
 
 void EventHandlerImplementation::Start(EventHandler* handler) {
   int result = Thread::Start(&EventHandlerImplementation::Poll,
                              reinterpret_cast<uword>(handler));
   if (result != 0) {
     FATAL1("Failed to start event handler thread %d", result);
   }
@@ skipping 22 matching lines @@
   // The hashmap does not support keys with value 0.
   return dart::Utils::WordHash(fd + 1);
 }
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // defined(HOST_OS_LINUX)
 
 #endif  // !defined(DART_IO_DISABLED)