Linux: Disable DBus auto-launch

services/service_manager/embedder/main.cc

 // Copyright 2017 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 "services/service_manager/embedder/main.h"
 
 #include "base/allocator/features.h"
 #include "base/at_exit.h"
 #include "base/base_switches.h"
 #include "base/command_line.h"
@@ skipping 320 matching lines @@
 
 int Main(const MainParams& params) {
   MainDelegate* delegate = params.delegate;
   DCHECK(delegate);
 
 #if defined(OS_MACOSX) && BUILDFLAG(USE_EXPERIMENTAL_ALLOCATOR_SHIM)
   base::allocator::InitializeAllocatorShim();
 #endif
   base::EnableTerminationOnOutOfMemory();
 
+#if defined(OS_LINUX)
+  // The various desktop environments set this environment variable that allows
+  // the dbus client library to connect directly to the bus. When this variable
+  // is not set (test environments like xvfb-run), the dbus client library will
+  // fall back to auto-launch mode. Auto-launch is dangerous as it can cause
+  // hangs (crbug.com/715658) . This one line disables the dbus auto-launch,
+  // by clobbering the DBUS_SESSION_BUS_ADDRESS env variable if not already set.
+  // The old auto-launch behavior, if needed, can be restored by setting
+  // DBUS_SESSION_BUS_ADDRESS="autolaunch:" before launching chrome.
+  const int kNoOverrideIfAlreadySet = 0;
+  setenv("DBUS_SESSION_BUS_ADDRESS", "disabled:", kNoOverrideIfAlreadySet);

[satorux1, 2017/05/08 01:30:37]

Several environmental variables, such as GNOME_DISABLE_CRASH_DIALOG, are set in
/opt/google/chrome/google-chrome. I'm wondering if this one could be also set in
that file. If that's not the case, might be nice to explain why, in the patch
description.

+#endif
+
 #if defined(OS_WIN)
   base::win::RegisterInvalidParamHandler();
   ui::win::CreateATLModuleIfNeeded();
 #endif  // defined(OS_WIN)
 
 #if !defined(OS_ANDROID)
   // On Android, the command line is initialized when library is loaded.
   int argc = 0;
   const char** argv = nullptr;
 
@@ skipping 121 matching lines @@
   autorelease_pool.reset();
 #endif
 
   if (process_type == ProcessType::kEmbedder)
     delegate->ShutDownEmbedderProcess();
 
   return exit_code;
 }
 
 }  // namespace service_manager