Refactor the bootstrap sandbox process launching integration.

sandbox/mac/pre_exec_delegate.cc

+// Copyright 2015 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 "sandbox/mac/pre_exec_delegate.h"
+
+#include <mach/mach.h>
+#include <servers/bootstrap.h>
+
+#include "base/logging.h"
+#include "sandbox/mac/bootstrap_sandbox.h"
+
+namespace sandbox {
+
+PreExecDelegate::PreExecDelegate(
+    const std::string& sandbox_server_bootstrap_name,
+    uint64_t sandbox_token)
+    : sandbox_server_bootstrap_name_(sandbox_server_bootstrap_name),
+      sandbox_server_bootstrap_name_ptr_(
+          sandbox_server_bootstrap_name_.c_str()),
+      sandbox_token_(sandbox_token) {
+}
+
+PreExecDelegate::~PreExecDelegate() {}
+
+void PreExecDelegate::RunAsyncSafe() {
+  mach_port_t sandbox_server_port = MACH_PORT_NULL;
+  kern_return_t kr = bootstrap_look_up(bootstrap_port,
+      sandbox_server_bootstrap_name_ptr_, &sandbox_server_port);
+  if (kr != KERN_SUCCESS)
+    RAW_LOG(FATAL, "Failed to look up bootstrap sandbox server port.");
+
+  mach_port_t new_bootstrap_port = MACH_PORT_NULL;
+  if (!BootstrapSandbox::ClientCheckIn(sandbox_server_port,
+                                       sandbox_token_,
+                                       &new_bootstrap_port)) {
+    RAW_LOG(FATAL, "Failed to check in with sandbox server.");
+  }
+
+  kr = task_set_bootstrap_port(mach_task_self(), new_bootstrap_port);
+  if (kr != KERN_SUCCESS)
+    RAW_LOG(FATAL, "Failed to replace bootstrap port.");
+
+  // On OS X 10.10 and higher, libxpc uses the port stash to transfer the
+  // XPC root port. This is effectively the same connection as the Mach
+  // bootstrap port, but not transferred using the task special port.
+  // Therefore, stash the replacement bootstrap port, so that on 10.10 it
+  // will be retrieved by the XPC code and used as a replacement for the
+  // XPC root port as well.
+  kr = mach_ports_register(mach_task_self(), &new_bootstrap_port, 1);

[Mark Mentovai, 2015/09/17 19:45:16]

Any reason to do this pre-10.10? It gives the child an unexpected extra send
right reference. If the child legitimately wanted to set its bootstrap port to
something even more restrictive, it’d unknowingly hang on to a reference to this
one.

[Robert Sesek, 2015/09/17 20:27:24]

Done.

+  if (kr != KERN_SUCCESS)
+    RAW_LOG(ERROR, "Failed to register replacement bootstrap port.");
+}
+
+}  // namespace sandbox