dbus: add support for passing file descriptors

dbus/message_unittest.cc

 // Copyright (c) 2012 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 "dbus/message.h"
 
 #include "base/basictypes.h"
+#include "base/eintr_wrapper.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "dbus/object_path.h"
 #include "dbus/test_proto.pb.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 // Test that a byte can be properly written and read. We only have this
 // test for byte, as repeating this for other basic types is too redundant.
 TEST(MessageTest, AppendAndPopByte) {
   scoped_ptr<dbus::Response> message(dbus::Response::CreateEmpty());
@@ skipping 69 matching lines @@
   EXPECT_EQ(3U, uint16_value);
   EXPECT_EQ(4, int32_value);
   EXPECT_EQ(5U, uint32_value);
   EXPECT_EQ(6, int64_value);
   EXPECT_EQ(7U, uint64_value);
   EXPECT_DOUBLE_EQ(8.0, double_value);
   EXPECT_EQ("string", string_value);
   EXPECT_EQ(dbus::ObjectPath("/object/path"), object_path_value);
 }
 
+// Check all basic types can be properly written and read.
+TEST(MessageTest, AppendAndPopFileDescriptor) {
+  if (!dbus::kDBusTypeUnixFdIsSupported) {
+    LOG(WARNING) << "FD passing is not supported";
+    return;
+  }
+
+  scoped_ptr<dbus::Response> message(dbus::Response::CreateEmpty());
+  dbus::MessageWriter writer(message.get());
+
+  // Append stdout.
+  dbus::FileDescriptor temp(1);
+  writer.AppendFileDescriptor(temp);
+
+  dbus::FileDescriptor fd_value;
+
+  dbus::MessageReader reader(message.get());
+  ASSERT_TRUE(reader.HasMoreData());
+  ASSERT_TRUE(reader.PopFileDescriptor(&fd_value));
+  ASSERT_FALSE(reader.HasMoreData());
+
+  // Stdout should be returned but we cannot check the descriptor
+  // value because stdout will be dup'd.  Instead check st_rdev
+  // which should be identical.
+  struct stat sb_stdout;
+  int status_stdout = HANDLE_EINTR(fstat(1, &sb_stdout));
+  ASSERT_TRUE(status_stdout >= 0);
+  struct stat sb_fd;
+  int status_fd = HANDLE_EINTR(fstat(fd_value.value(), &sb_fd));
+  ASSERT_TRUE(status_fd >= 0);
+  EXPECT_EQ(sb_stdout.st_rdev, sb_fd.st_rdev);
+}
+
 // Check all variant types can be properly written and read.
 TEST(MessageTest, AppendAndPopVariantDataTypes) {
   scoped_ptr<dbus::Response> message(dbus::Response::CreateEmpty());
   dbus::MessageWriter writer(message.get());
 
   // Append 0, 1, 2, 3, 4, 5, 6, 7, 8, "string", "/object/path".
   writer.AppendVariantOfByte(0);
   writer.AppendVariantOfBool(true);
   writer.AppendVariantOfInt16(2);
   writer.AppendVariantOfUint16(3);
@@ skipping 426 matching lines @@
 
   EXPECT_EQ("org.chromium.destination", message->GetDestination());
   EXPECT_EQ(dbus::ObjectPath("/org/chromium/path"), message->GetPath());
   EXPECT_EQ("org.chromium.interface", message->GetInterface());
   EXPECT_EQ("member", message->GetMember());
   EXPECT_EQ("org.chromium.error", message->GetErrorName());
   EXPECT_EQ(":1.2", message->GetSender());
   EXPECT_EQ(123U, message->GetSerial());
   EXPECT_EQ(456U, message->GetReplySerial());
 }