[mojo-edk] Add support for transferring mach ports.

mojo/edk/test/mojo_test_base.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "mojo/edk/test/mojo_test_base.h"
 
 #include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
 #include "mojo/edk/embedder/embedder.h"
 #include "mojo/edk/system/handle_signals_state.h"
 #include "mojo/public/c/system/buffer.h"
 #include "mojo/public/c/system/data_pipe.h"
 #include "mojo/public/c/system/functions.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
+#if defined(OS_MACOSX) && !defined(OS_IOS)
+#include "base/mac/mach_port_broker.h"
+#endif
+
 namespace mojo {
 namespace edk {
 namespace test {
 
+
+#if defined(OS_MACOSX) && !defined(OS_IOS)
+namespace {
+base::MachPortBroker* g_mach_broker = nullptr;
+}
+#endif
+
 MojoTestBase::MojoTestBase() {
+#if defined(OS_MACOSX) && !defined(OS_IOS)
+  if (!g_mach_broker) {
+    g_mach_broker = new base::MachPortBroker("mojo_test");
+    CHECK(g_mach_broker->Init());
+    SetMachPortProviderIfNeeded(g_mach_broker);
+  }
+#endif
 }
 
 MojoTestBase::~MojoTestBase() {}
 
 MojoTestBase::ClientController& MojoTestBase::StartClient(
     const std::string& client_name) {
   clients_.push_back(
       make_scoped_ptr(new ClientController(client_name, this)));
   return *clients_.back();
 }
 
 MojoTestBase::ClientController::ClientController(const std::string& client_name,
                                                  MojoTestBase* test)
-    : test_(test)
+    : test_(test) {
 #if !defined(OS_IOS)
-      ,
-      pipe_(helper_.StartChild(client_name))
+#if defined(OS_MACOSX)
+  // This lock needs to be held while launching the child because the Mach port
+  // broker only allows task ports to be received from known child processes.
+  // However, it can only know the child process's pid after the child has
+  // launched. To prevent a race where the child process sends its task port
+  // before the pid has been registered, the lock needs to be held over both
+  // launch and child pid registration.
+  base::AutoLock lock(g_mach_broker->GetLock());
 #endif
-{
+  pipe_ = helper_.StartChild(client_name);
+#if defined(OS_MACOSX)
+  g_mach_broker->AddPlaceholderForPid(helper_.test_child().Handle());
+#endif
+#endif
 }
 
 MojoTestBase::ClientController::~ClientController() {
   CHECK(was_shutdown_)
       << "Test clients should be waited on explicitly with WaitForShutdown().";
 }
 
 int MojoTestBase::ClientController::WaitForShutdown() {
   was_shutdown_ = true;
 #if !defined(OS_IOS)
-  return helper_.WaitForChildShutdown();
+  int retval = helper_.WaitForChildShutdown();
+#if defined(OS_MACOSX)
+  base::AutoLock lock(g_mach_broker->GetLock());
+  g_mach_broker->InvalidatePid(helper_.test_child().Handle());
+#endif
+  return retval;
 #else
   NOTREACHED();
   return 1;
 #endif
 }
 
 // static
 void MojoTestBase::CloseHandle(MojoHandle h) {
   EXPECT_EQ(MOJO_RESULT_OK, MojoClose(h));
 }
@@ skipping 199 matching lines @@
                          MOJO_WRITE_DATA_FLAG_ALL_OR_NONE),
            MOJO_RESULT_OK);
   CHECK_EQ(num_bytes, static_cast<uint32_t>(size));
 
   return std::string(buffer.data(), buffer.size());
 }
 
 }  // namespace test
 }  // namespace edk
 }  // namespace mojo