For Linux, create a ZygoteForkDelegate that uses the nacl_helper executable

chrome/nacl/nacl_launcher_thread.cc

-// Copyright (c) 2011 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 "chrome/nacl/nacl_launcher_thread.h"
-
-#include <vector>
-
-#include "base/atomicops.h"
-#include "base/memory/scoped_ptr.h"
-#include "chrome/common/nacl_messages.h"
-#include "native_client/src/shared/imc/nacl_imc.h"
-
-#if defined(OS_LINUX)
-#include "content/common/child_process_sandbox_support_linux.h"
-#endif
-
-#if defined(OS_WIN)
-#include <fcntl.h>
-#include <io.h>
-#endif
-
-#if defined(OS_MACOSX)
-namespace {
-
-// On Mac OS X, shm_open() works in the sandbox but does not give us
-// an FD that we can map as PROT_EXEC.  Rather than doing an IPC to
-// get an executable SHM region when CreateMemoryObject() is called,
-// we preallocate one on startup, since NaCl's sel_ldr only needs one
-// of them.  This saves a round trip.
-
-base::subtle::Atomic32 g_shm_fd = -1;
-
-int CreateMemoryObject(size_t size, bool executable) {
-  if (executable && size > 0) {
-    int result_fd = base::subtle::NoBarrier_AtomicExchange(&g_shm_fd, -1);
-    if (result_fd != -1) {
-      // ftruncate() is disallowed by the Mac OS X sandbox and
-      // returns EPERM.  Luckily, we can get the same effect with
-      // lseek() + write().
-      if (lseek(result_fd, size - 1, SEEK_SET) == -1) {
-        LOG(ERROR) << "lseek() failed: " << errno;
-        return -1;
-      }
-      if (write(result_fd, "", 1) != 1) {
-        LOG(ERROR) << "write() failed: " << errno;
-        return -1;
-      }
-      return result_fd;
-    }
-  }
-  // Fall back to NaCl's default implementation.
-  return -1;
-}
-
-}  // namespace
-#endif  // defined(OS_MACOSX)
-
-// This is ugly.  We need an interface header file for the exported
-// sel_ldr interfaces.
-// TODO(gregoryd,sehr): Add an interface header.
-#if defined(OS_WIN)
-typedef HANDLE NaClHandle;
-#else
-typedef int NaClHandle;
-#endif  // NaClHandle
-
-// This is currently necessary because we have a conflict between
-// NaCl's LOG_FATAL (from platform/nacl_log.h) and Chromium's
-// LOG_FATAL (from base/logging.h).
-extern "C" int NaClMainForChromium(int handle_count, const NaClHandle* handles,
-                                   int debug);
-extern "C" void NaClSetIrtFileDesc(int fd);
-
-NaClLauncherThread::NaClLauncherThread(bool debug) {
-  debug_enabled_ = debug ? 1 : 0;
-}
-
-NaClLauncherThread::~NaClLauncherThread() {
-}
-
-NaClLauncherThread* NaClLauncherThread::current() {
-  return static_cast<NaClLauncherThread*>(ChildThread::current());
-}
-
-bool NaClLauncherThread::OnControlMessageReceived(const IPC::Message& msg) {
-  bool handled = true;
-  IPC_BEGIN_MESSAGE_MAP(NaClLauncherThread, msg)
-    IPC_MESSAGE_HANDLER(NaClProcessMsg_Start, OnStartSelLdr)
-    IPC_MESSAGE_UNHANDLED(handled = false)
-  IPC_END_MESSAGE_MAP()
-  return handled;
-}
-
-void NaClLauncherThread::OnStartSelLdr(
-    std::vector<nacl::FileDescriptor> handles,
-    bool have_irt_file) {
-#if defined(OS_LINUX)
-  nacl::SetCreateMemoryObjectFunc(
-      child_process_sandbox_support::MakeSharedMemorySegmentViaIPC);
-#elif defined(OS_MACOSX)
-  nacl::SetCreateMemoryObjectFunc(CreateMemoryObject);
-  CHECK(handles.size() >= 1);
-  g_shm_fd = nacl::ToNativeHandle(handles[handles.size() - 1]);
-  handles.pop_back();
-#endif
-
-  if (have_irt_file) {
-    CHECK(handles.size() >= 1);
-    NaClHandle irt_handle = nacl::ToNativeHandle(handles[handles.size() - 1]);
-    handles.pop_back();
-#if defined(OS_WIN)
-    int irt_desc = _open_osfhandle(reinterpret_cast<intptr_t>(irt_handle),
-                                   _O_RDWR | _O_BINARY);
-    if (irt_desc < 0) {
-      LOG(ERROR) << "_open_osfhandle() failed";
-      return;
-    }
-#else
-    int irt_desc = irt_handle;
-#endif
-    NaClSetIrtFileDesc(irt_desc);
-  }
-
-  scoped_array<NaClHandle> array(new NaClHandle[handles.size()]);
-  for (size_t i = 0; i < handles.size(); i++) {
-    array[i] = nacl::ToNativeHandle(handles[i]);
-  }
-  NaClMainForChromium(static_cast<int>(handles.size()), array.get(),
-                      debug_enabled_);
-}