Pass StatsTable shared memory via global descriptors on Posix rather than using named shared memory.

components/nacl/zygote/nacl_fork_delegate_linux.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 "components/nacl/zygote/nacl_fork_delegate_linux.h"
 
 #include <signal.h>
 #include <stdlib.h>
 #include <sys/resource.h>
 #include <sys/socket.h>
 
 #include <set>
 
 #include "base/basictypes.h"
 #include "base/command_line.h"
 #include "base/cpu.h"
 #include "base/files/file_path.h"
 #include "base/logging.h"
 #include "base/path_service.h"
 #include "base/pickle.h"
 #include "base/posix/eintr_wrapper.h"
+#include "base/posix/global_descriptors.h"
 #include "base/posix/unix_domain_socket_linux.h"
 #include "base/process/kill.h"
 #include "base/process/launch.h"
 #include "base/third_party/dynamic_annotations/dynamic_annotations.h"
 #include "components/nacl/common/nacl_helper_linux.h"
 #include "components/nacl/common/nacl_paths.h"
 #include "components/nacl/common/nacl_switches.h"
+#include "content/public/common/content_descriptors.h"
 #include "content/public/common/content_switches.h"
 
 namespace {
 
 // Note these need to match up with their counterparts in nacl_helper_linux.c
 // and nacl_helper_bootstrap_linux.c.
 const char kNaClHelperReservedAtZero[] =
     "--reserved_at_zero=0xXXXXXXXXXXXXXXXX";
 const char kNaClHelperRDebug[] = "--r_debug=0xXXXXXXXXXXXXXXXX";
 
@@ skipping 64 matching lines @@
 }  // namespace.
 
 NaClForkDelegate::NaClForkDelegate()
     : status_(kNaClHelperUnused),
       fd_(-1) {}
 
 void NaClForkDelegate::Init(const int sandboxdesc) {
   VLOG(1) << "NaClForkDelegate::Init()";
   int fds[2];
 
+  // For communications between the NaCl loader process and
+  // the SUID sandbox.
+  int nacl_sandbox_descriptor =
+      base::GlobalDescriptors::kBaseDescriptor + kSandboxIPCChannel;
   // Confirm a hard-wired assumption.
-  // The NaCl constant is from chrome/nacl/nacl_linux_helper.h
-  DCHECK(kNaClSandboxDescriptor == sandboxdesc);
+  DCHECK_EQ(sandboxdesc, nacl_sandbox_descriptor);
 
   CHECK(socketpair(PF_UNIX, SOCK_SEQPACKET, 0, fds) == 0);
   base::FileHandleMappingVector fds_to_map;
   fds_to_map.push_back(std::make_pair(fds[1], kNaClZygoteDescriptor));
-  fds_to_map.push_back(std::make_pair(sandboxdesc, kNaClSandboxDescriptor));
+  fds_to_map.push_back(std::make_pair(sandboxdesc, nacl_sandbox_descriptor));
 
   // Using nacl_helper_bootstrap is not necessary on x86-64 because
   // NaCl's x86-64 sandbox is not zero-address-based.  Starting
   // nacl_helper through nacl_helper_bootstrap works on x86-64, but it
   // leaves nacl_helper_bootstrap mapped at a fixed address at the
   // bottom of the address space, which is undesirable because it
   // effectively defeats ASLR.
 #if defined(ARCH_CPU_X86_64)
   bool kUseNaClBootstrap = false;
 #elif defined(ARCH_CPU_X86)
@@ skipping 201 matching lines @@
   int remote_exit_code;
   if (!iter.ReadInt(&remote_exit_code)) {
     LOG(ERROR) << "GetTerminationStatus: pickle failed";
     return false;
   }
 
   *status = static_cast<base::TerminationStatus>(termination_status);
   *exit_code = remote_exit_code;
   return true;
 }