Alter the design of the bootstrap sandbox to only take over the bootstrap port of children when nec…

base/process/launch_mac.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 "base/process/launch.h"
 
 #include <mach/mach.h>
+#include <servers/bootstrap.h>
+
+#include "base/logging.h"
 
 namespace base {
 
 void RestoreDefaultExceptionHandler() {
   // This function is tailored to remove the Breakpad exception handler.
   // exception_mask matches s_exception_mask in
   // breakpad/src/client/mac/handler/exception_handler.cc
   const exception_mask_t exception_mask = EXC_MASK_BAD_ACCESS |
                                           EXC_MASK_BAD_INSTRUCTION |
                                           EXC_MASK_ARITHMETIC |
                                           EXC_MASK_BREAKPOINT;
 
   // Setting the exception port to MACH_PORT_NULL may not be entirely
   // kosher to restore the default exception handler, but in practice,
   // it results in the exception port being set to Apple Crash Reporter,
   // the desired behavior.
   task_set_exception_ports(mach_task_self(), exception_mask, MACH_PORT_NULL,
                            EXCEPTION_DEFAULT, THREAD_STATE_NONE);
 }
 
+void ReplaceBootstrapPort(const std::string& new_bootstrap_name) {
+  // This function is called between fork() and exec(), so it should take care
+  // to run properly in that situation.
+
+  mach_port_t port = MACH_PORT_NULL;
+  kern_return_t kr = bootstrap_look_up(bootstrap_port,
+      new_bootstrap_name.c_str(), &port);
+  if (kr != KERN_SUCCESS) {
+    RAW_LOG(FATAL, "Failed to look up replacement bootstrap port.");
+  }
+
+  kr = task_set_bootstrap_port(mach_task_self(), port);
+  if (kr != KERN_SUCCESS) {
+    RAW_LOG(FATAL, "Failed to replace bootstrap port.");
+  }
+}
+
 }  // namespace base