Put app shim IPC socket in a temporary directory. (Mac)

apps/app_shim/app_shim_host_manager_mac.mm

 // Copyright 2013 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 "apps/app_shim/app_shim_host_manager_mac.h"
 
 #include "apps/app_shim/app_shim_handler_mac.h"
 #include "apps/app_shim/app_shim_host_mac.h"
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/files/file_path.h"
 #include "base/logging.h"
 #include "base/path_service.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/common/chrome_paths.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/mac/app_mode_common.h"
-#include "ipc/unix_domain_socket_util.h"
 
 using content::BrowserThread;
 
 namespace {
 
 void CreateAppShimHost(const IPC::ChannelHandle& handle) {
   // AppShimHost takes ownership of itself.
   (new AppShimHost)->ServeChannel(handle);
 }
 
 }  // namespace
 
-const base::FilePath* AppShimHostManager::g_override_user_data_dir_ = NULL;
-
 AppShimHostManager::AppShimHostManager() {}
 
 void AppShimHostManager::Init() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   apps::AppShimHandler::SetDefaultHandler(&extension_app_shim_handler_);
   BrowserThread::PostTask(
       BrowserThread::FILE, FROM_HERE,
       base::Bind(&AppShimHostManager::InitOnFileThread, this));
 }
 
 AppShimHostManager::~AppShimHostManager() {
   apps::AppShimHandler::SetDefaultHandler(NULL);
 }
 
 void AppShimHostManager::InitOnFileThread() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
   base::FilePath user_data_dir;
-  if (g_override_user_data_dir_) {
-    user_data_dir = *g_override_user_data_dir_;
-  } else if (!PathService::Get(chrome::DIR_USER_DATA, &user_data_dir)) {
+  if (!PathService::Get(chrome::DIR_USER_DATA, &user_data_dir)) {
     LOG(ERROR) << "Couldn't get user data directory while creating App Shim "

[tapted, 2013/11/21 11:12:05]

while we are here.. let's ditch this LOG and just return. Chrome would have
already died due to a CHECK(..) in chrome::GetUserDataDir() called from
ChromeBrowserMainParts::PreCreateThreadsImpl()

[jackhou1, 2013/11/22 00:20:40]

Done.

                << "Host manager.";
     return;
   }
 
+  // The socket cannot be created if its path is longer than 128 chars
+  // (IPC::kMaxSocketNameLength). To circumvent this, we use a short path in
+  // /tmp/ that is generated from a hash of the user data dir.
+  base::FilePath udd_plus_socket_name =
+      user_data_dir.Append(app_mode::kAppShimSocketName);
   base::FilePath socket_path =
-      user_data_dir.Append(app_mode::kAppShimSocketName);
-  // This mirrors a check in unix_domain_socket_util.cc which will guarantee
-  // failure and spam log files on bots because they have deeply nested paths to
-  // |user_data_dir| when swarming. See http://crbug.com/240554. Shim tests that
-  // run on the bots must override the path using AppShimHostManagerTestApi.
-  if (socket_path.value().length() >= IPC::kMaxSocketNameLength &&
-      CommandLine::ForCurrentProcess()->HasSwitch(switches::kTestType)) {
-    return;
-  }
+      app_mode::GetShortSocketPath(udd_plus_socket_name);

[tapted, 2013/11/21 11:12:05]

Ah, so this is just /tmp/TWFuIGlzIGRpc3Rpbm which a domain socket. I think we
should put it in something like /tmp/TWFuIGlzIGRpc3Rpbm/Chrome\ App\ Shim\
Socket

Otherwise (a) the user has no information about what this file in /tmp is for;
and (b) I think OSX doesn't properly enforce permissions on the socket file
itself, but (I think!) should still enforce it on the parent folder.

and be sure to create /tmp/TWFuIGlzIGRpc3Rpbm/ with restricted privileges (mode
700, etc.). It also needs to be a scoped folder.

One other concern... One might `sudo rm -rf /tmp/*`. Heck, I'm tempted to do it
now because I jst noticed puppet::mac has gone berserk and made 2000 tmpXXXX
files in there :|. But I don't think this is an issue.

Actually, I just found out that Spotlight does just what this is doing, so +1
/tmp

$ sudo ls -l /tmp/launchd-817.3J2EoS/
total 0
srwx------  1 _spotlight  wheel  0 13 Nov 09:39 sock

And there's an idea for preventing (the super improbable) name collisions, you
could use a path like

/tmp/chrome-PID-TWFuIGlzIGRpc3Rpbm/sock

Do you think it's worthwhile?

[jackhou1, 2013/11/22 00:20:40]

Yeah, I think this is a good idea. I've changed the directory to just hash the
UDD, so /tmp/chrome-<hash>/ is kind of a proxy UDD, and "App Shim Socket" goes
in there.

 
   factory_.reset(new IPC::ChannelFactory(socket_path, this));
   BrowserThread::PostTask(
       BrowserThread::IO, FROM_HERE,
       base::Bind(&AppShimHostManager::ListenOnIOThread, this));
 }
 
 void AppShimHostManager::ListenOnIOThread() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
   if (!factory_->Listen()) {
@@ skipping 10 matching lines @@
       BrowserThread::UI, FROM_HERE,
       base::Bind(&CreateAppShimHost, handle));
 }
 
 void AppShimHostManager::OnListenError() {
   // TODO(tapted): Set a timeout and attempt to reconstruct the channel. Until
   // cases where the error could occur are better known, just reset the factory
   // to allow failure to be communicated via the test API.
   factory_.reset();
 }