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

apps/app_shim/app_shim_host_manager_mac.mm

Index: apps/app_shim/app_shim_host_manager_mac.mm
diff --git a/apps/app_shim/app_shim_host_manager_mac.mm b/apps/app_shim/app_shim_host_manager_mac.mm
index eeaa114adea0e03b5921483ca98379a4ffeee43b..d509fa1f30ab6d6da8a397f473216c83ce8799b0 100644
--- a/apps/app_shim/app_shim_host_manager_mac.mm
+++ b/apps/app_shim/app_shim_host_manager_mac.mm
@@ -15,7 +15,6 @@
 #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;
 
@@ -28,8 +27,6 @@ void CreateAppShimHost(const IPC::ChannelHandle& handle) {
 
 }  // namespace
 
-const base::FilePath* AppShimHostManager::g_override_user_data_dir_ = NULL;
-
 AppShimHostManager::AppShimHostManager() {}
 
 void AppShimHostManager::Init() {
@@ -47,24 +44,19 @@ AppShimHostManager::~AppShimHostManager() {
 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;
   }
 
-  base::FilePath socket_path =
+  // 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);
-  // 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;
-  }
+  base::FilePath socket_path =
+      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(