Enable one PID namespace per process for NaCl processes.

sandbox/linux/services/namespace_sandbox.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/linux/services/namespace_sandbox.h"
 
 #include <sched.h>
 #include <signal.h>
 #include <stdlib.h>
 #include <sys/types.h>
@@ skipping 59 matching lines @@
 int g_signal_exit_codes[64];
 
 void TerminationSignalHandler(int sig) {
   // Return a special exit code so that the process is detected as terminated by
   // a signal.
   const size_t sig_idx = static_cast<size_t>(sig);
   if (sig_idx < arraysize(g_signal_exit_codes)) {
     _exit(g_signal_exit_codes[sig_idx]);
   }
 
-  _exit(NamespaceSandbox::kDefaultExitCode);
+  _exit(NamespaceSandbox::SignalExitCode(sig));
 }
 #endif  // !defined(OS_NACL_NONSFI)
 
 }  // namespace
 
 #if !defined(OS_NACL_NONSFI)
 // static
 base::Process NamespaceSandbox::LaunchProcess(
     const base::CommandLine& cmdline,
     const base::LaunchOptions& options) {
@@ skipping 59 matching lines @@
   return pid;
 }
 
 // static
 void NamespaceSandbox::InstallDefaultTerminationSignalHandlers() {
   static const int kDefaultTermSignals[] = {
       SIGHUP, SIGINT, SIGABRT, SIGQUIT, SIGPIPE, SIGTERM, SIGUSR1, SIGUSR2,
   };
 
   for (const int sig : kDefaultTermSignals) {
-    InstallTerminationSignalHandler(sig, kDefaultExitCode);
+    InstallTerminationSignalHandler(sig, SignalExitCode(sig));
   }
 }
 
 // static
 bool NamespaceSandbox::InstallTerminationSignalHandler(
     int sig,
     int exit_code) {
   struct sigaction old_action;
   PCHECK(sigaction(sig, nullptr, &old_action) == 0);
 
@@ skipping 28 matching lines @@
 bool NamespaceSandbox::InNewPidNamespace() {
   return getenv(kSandboxPIDNSEnvironmentVarName) != nullptr;
 }
 
 // static
 bool NamespaceSandbox::InNewNetNamespace() {
   return getenv(kSandboxNETNSEnvironmentVarName) != nullptr;
 }
 
 }  // namespace sandbox