src/components/nacl/browser/nacl_process_host.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "components/nacl/browser/nacl_process_host.h"
   6
   7 #include <algorithm>
   8 #include <string>
   9 #include <vector>
  10
  11 #include "base/base_switches.h"
  12 #include "base/bind.h"
  13 #include "base/command_line.h"
  14 #include "base/files/file_util.h"
  15 #include "base/message_loop/message_loop.h"
  16 #include "base/metrics/histogram.h"
  17 #include "base/path_service.h"
  18 #include "base/process/launch.h"
  19 #include "base/process/process_iterator.h"
  20 #include "base/rand_util.h"
  21 #include "base/strings/string_number_conversions.h"
  22 #include "base/strings/string_split.h"
  23 #include "base/strings/string_util.h"
  24 #include "base/strings/stringprintf.h"
  25 #include "base/strings/utf_string_conversions.h"
  26 #include "base/threading/sequenced_worker_pool.h"
  27 #include "base/win/windows_version.h"
  28 #include "build/build_config.h"
  29 #include "components/nacl/browser/nacl_browser.h"
  30 #include "components/nacl/browser/nacl_browser_delegate.h"
  31 #include "components/nacl/browser/nacl_host_message_filter.h"
  32 #include "components/nacl/common/nacl_cmd_line.h"
  33 #include "components/nacl/common/nacl_host_messages.h"
  34 #include "components/nacl/common/nacl_messages.h"
  35 #include "components/nacl/common/nacl_process_type.h"
  36 #include "components/nacl/common/nacl_switches.h"
  37 #include "content/public/browser/browser_child_process_host.h"
  38 #include "content/public/browser/browser_ppapi_host.h"
  39 #include "content/public/browser/child_process_data.h"
  40 #include "content/public/browser/plugin_service.h"
  41 #include "content/public/browser/render_process_host.h"
  42 #include "content/public/browser/web_contents.h"
  43 #include "content/public/common/child_process_host.h"
  44 #include "content/public/common/content_switches.h"
  45 #include "content/public/common/process_type.h"
  46 #include "content/public/common/sandboxed_process_launcher_delegate.h"
  47 #include "ipc/ipc_channel.h"
  48 #include "ipc/ipc_switches.h"
  49 #include "native_client/src/public/nacl_file_info.h"
  50 #include "native_client/src/shared/imc/nacl_imc_c.h"
  51 #include "net/base/net_util.h"
  52 #include "net/socket/tcp_listen_socket.h"
  53 #include "ppapi/host/host_factory.h"
  54 #include "ppapi/host/ppapi_host.h"
  55 #include "ppapi/proxy/ppapi_messages.h"
  56 #include "ppapi/shared_impl/ppapi_constants.h"
  57 #include "ppapi/shared_impl/ppapi_nacl_plugin_args.h"
  58
  59 #if defined(OS_POSIX)
  60
  61 #include <fcntl.h>
  62
  63 #include "ipc/ipc_channel_posix.h"
  64 #elif defined(OS_WIN)
  65 #include <windows.h>
  66
  67 #include "base/threading/thread.h"
  68 #include "base/win/scoped_handle.h"
  69 #include "components/nacl/browser/nacl_broker_service_win.h"
  70 #include "components/nacl/common/nacl_debug_exception_handler_win.h"
  71 #include "content/public/common/sandbox_init.h"
  72 #endif
  73
  74 using content::BrowserThread;
  75 using content::ChildProcessData;
  76 using content::ChildProcessHost;
  77 using ppapi::proxy::SerializedHandle;
  78
  79 namespace nacl {
  80
  81 #if defined(OS_WIN)
  82 namespace {
  83
  84 // Looks for the largest contiguous unallocated region of address
  85 // space and returns it via |*out_addr| and |*out_size|.
  86 void FindAddressSpace(base::ProcessHandle process,
  87                       char** out_addr, size_t* out_size) {
  88   *out_addr = NULL;
  89   *out_size = 0;
  90   char* addr = 0;
  91   while (true) {
  92     MEMORY_BASIC_INFORMATION info;
  93     size_t result = VirtualQueryEx(process, static_cast<void*>(addr),
  94                                    &info, sizeof(info));
  95     if (result < sizeof(info))
  96       break;
  97     if (info.State == MEM_FREE && info.RegionSize > *out_size) {
  98       *out_addr = addr;
  99       *out_size = info.RegionSize;
 100     }
 101     addr += info.RegionSize;
 102   }
 103 }
 104
 105 #ifdef _DLL
 106
 107 bool IsInPath(const std::string& path_env_var, const std::string& dir) {
 108   std::vector<std::string> split;
 109   base::SplitString(path_env_var, ';', &split);
 110   for (std::vector<std::string>::const_iterator i(split.begin());
 111        i != split.end();
 112        ++i) {
 113     if (*i == dir)
 114       return true;
 115   }
 116   return false;
 117 }
 118
 119 #endif  // _DLL
 120
 121 }  // namespace
 122
 123 // Allocates |size| bytes of address space in the given process at a
 124 // randomised address.
 125 void* AllocateAddressSpaceASLR(base::ProcessHandle process, size_t size) {
 126   char* addr;
 127   size_t avail_size;
 128   FindAddressSpace(process, &addr, &avail_size);
 129   if (avail_size < size)
 130     return NULL;
 131   size_t offset = base::RandGenerator(avail_size - size);
 132   const int kPageSize = 0x10000;
 133   void* request_addr =
 134       reinterpret_cast<void*>(reinterpret_cast<uint64>(addr + offset)
 135                               & ~(kPageSize - 1));
 136   return VirtualAllocEx(process, request_addr, size,
 137                         MEM_RESERVE, PAGE_NOACCESS);
 138 }
 139
 140 namespace {
 141
 142 bool RunningOnWOW64() {
 143   return (base::win::OSInfo::GetInstance()->wow64_status() ==
 144           base::win::OSInfo::WOW64_ENABLED);
 145 }
 146
 147 }  // namespace
 148
 149 #endif  // defined(OS_WIN)
 150
 151 namespace {
 152
 153 // NOTE: changes to this class need to be reviewed by the security team.
 154 class NaClSandboxedProcessLauncherDelegate
 155     : public content::SandboxedProcessLauncherDelegate {
 156  public:
 157   NaClSandboxedProcessLauncherDelegate(ChildProcessHost* host)
 158 #if defined(OS_POSIX)
 159       : ipc_fd_(host->TakeClientFileDescriptor())
 160 #endif
 161   {}
 162
 163   ~NaClSandboxedProcessLauncherDelegate() override {}
 164
 165 #if defined(OS_WIN)
 166   virtual void PostSpawnTarget(base::ProcessHandle process) {
 167     // For Native Client sel_ldr processes on 32-bit Windows, reserve 1 GB of
 168     // address space to prevent later failure due to address space fragmentation
 169     // from .dll loading. The NaCl process will attempt to locate this space by
 170     // scanning the address space using VirtualQuery.
 171     // TODO(bbudge) Handle the --no-sandbox case.
 172     // http://code.google.com/p/nativeclient/issues/detail?id=2131
 173     const SIZE_T kNaClSandboxSize = 1 << 30;
 174     if (!nacl::AllocateAddressSpaceASLR(process, kNaClSandboxSize)) {
 175       DLOG(WARNING) << "Failed to reserve address space for Native Client";
 176     }
 177   }
 178 #elif defined(OS_POSIX)
 179   bool ShouldUseZygote() override { return true; }
 180   base::ScopedFD TakeIpcFd() override { return ipc_fd_.Pass(); }
 181 #endif  // OS_WIN
 182
 183  private:
 184 #if defined(OS_POSIX)
 185   base::ScopedFD ipc_fd_;
 186 #endif  // OS_POSIX
 187 };
 188
 189 void SetCloseOnExec(NaClHandle fd) {
 190 #if defined(OS_POSIX)
 191   int flags = fcntl(fd, F_GETFD);
 192   CHECK_NE(flags, -1);
 193   int rc = fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
 194   CHECK_EQ(rc, 0);
 195 #endif
 196 }
 197
 198 bool ShareHandleToSelLdr(
 199     base::ProcessHandle processh,
 200     NaClHandle sourceh,
 201     bool close_source,
 202     std::vector<nacl::FileDescriptor> *handles_for_sel_ldr) {
 203 #if defined(OS_WIN)
 204   HANDLE channel;
 205   int flags = DUPLICATE_SAME_ACCESS;
 206   if (close_source)
 207     flags |= DUPLICATE_CLOSE_SOURCE;
 208   if (!DuplicateHandle(GetCurrentProcess(),
 209                        reinterpret_cast<HANDLE>(sourceh),
 210                        processh,
 211                        &channel,
 212                        0,  // Unused given DUPLICATE_SAME_ACCESS.
 213                        FALSE,
 214                        flags)) {
 215     LOG(ERROR) << "DuplicateHandle() failed";
 216     return false;
 217   }
 218   handles_for_sel_ldr->push_back(
 219       reinterpret_cast<nacl::FileDescriptor>(channel));
 220 #else
 221   nacl::FileDescriptor channel;
 222   channel.fd = sourceh;
 223   channel.auto_close = close_source;
 224   handles_for_sel_ldr->push_back(channel);
 225 #endif
 226   return true;
 227 }
 228
 229 }  // namespace
 230
 231 unsigned NaClProcessHost::keepalive_throttle_interval_milliseconds_ =
 232     ppapi::kKeepaliveThrottleIntervalDefaultMilliseconds;
 233
 234 NaClProcessHost::NaClProcessHost(const GURL& manifest_url,
 235                                  base::File nexe_file,
 236                                  const NaClFileToken& nexe_token,
 237                                  ppapi::PpapiPermissions permissions,
 238                                  int render_view_id,
 239                                  uint32 permission_bits,
 240                                  bool uses_nonsfi_mode,
 241                                  bool off_the_record,
 242                                  NaClAppProcessType process_type,
 243                                  const base::FilePath& profile_directory)
 244     : manifest_url_(manifest_url),
 245       nexe_file_(nexe_file.Pass()),
 246       nexe_token_(nexe_token),
 247       permissions_(permissions),
 248 #if defined(OS_WIN)
 249       process_launched_by_broker_(false),
 250 #endif
 251       reply_msg_(NULL),
 252 #if defined(OS_WIN)
 253       debug_exception_handler_requested_(false),
 254 #endif
 255       uses_nonsfi_mode_(uses_nonsfi_mode),
 256       enable_debug_stub_(false),
 257       enable_crash_throttling_(false),
 258       off_the_record_(off_the_record),
 259       process_type_(process_type),
 260       profile_directory_(profile_directory),
 261       render_view_id_(render_view_id),
 262       weak_factory_(this) {
 263   process_.reset(content::BrowserChildProcessHost::Create(
 264       PROCESS_TYPE_NACL_LOADER, this));
 265
 266   // Set the display name so the user knows what plugin the process is running.
 267   // We aren't on the UI thread so getting the pref locale for language
 268   // formatting isn't possible, so IDN will be lost, but this is probably OK
 269   // for this use case.
 270   process_->SetName(net::FormatUrl(manifest_url_, std::string()));
 271
 272   enable_debug_stub_ = CommandLine::ForCurrentProcess()->HasSwitch(
 273       switches::kEnableNaClDebug);
 274   DCHECK(process_type_ != kUnknownNaClProcessType);
 275   enable_crash_throttling_ = process_type_ != kNativeNaClProcessType;
 276 }
 277
 278 NaClProcessHost::~NaClProcessHost() {
 279   // Report exit status only if the process was successfully started.
 280   if (process_->GetData().handle != base::kNullProcessHandle) {
 281     int exit_code = 0;
 282     process_->GetTerminationStatus(false /* known_dead */, &exit_code);
 283     std::string message =
 284         base::StringPrintf("NaCl process exited with status %i (0x%x)",
 285                            exit_code, exit_code);
 286     if (exit_code == 0) {
 287       VLOG(1) << message;
 288     } else {
 289       LOG(ERROR) << message;
 290     }
 291     NaClBrowser::GetInstance()->OnProcessEnd(process_->GetData().id);
 292   }
 293
 294   if (reply_msg_) {
 295     // The process failed to launch for some reason.
 296     // Don't keep the renderer hanging.
 297     reply_msg_->set_reply_error();
 298     nacl_host_message_filter_->Send(reply_msg_);
 299   }
 300 #if defined(OS_WIN)
 301   if (process_launched_by_broker_) {
 302     NaClBrokerService::GetInstance()->OnLoaderDied();
 303   }
 304 #endif
 305 }
 306
 307 void NaClProcessHost::OnProcessCrashed(int exit_status) {
 308   if (enable_crash_throttling_ &&
 309       !CommandLine::ForCurrentProcess()->HasSwitch(
 310           switches::kDisablePnaclCrashThrottling)) {
 311     NaClBrowser::GetInstance()->OnProcessCrashed();
 312   }
 313 }
 314
 315 // This is called at browser startup.
 316 // static
 317 void NaClProcessHost::EarlyStartup() {
 318   NaClBrowser::GetInstance()->EarlyStartup();
 319   // Inform NaClBrowser that we exist and will have a debug port at some point.
 320 #if defined(OS_LINUX) && !defined(OS_CHROMEOS)
 321   // Open the IRT file early to make sure that it isn't replaced out from
 322   // under us by autoupdate.
 323   NaClBrowser::GetInstance()->EnsureIrtAvailable();
 324 #endif
 325   CommandLine* cmd = CommandLine::ForCurrentProcess();
 326   UMA_HISTOGRAM_BOOLEAN(
 327       "NaCl.nacl-gdb",
 328       !cmd->GetSwitchValuePath(switches::kNaClGdb).empty());
 329   UMA_HISTOGRAM_BOOLEAN(
 330       "NaCl.nacl-gdb-script",
 331       !cmd->GetSwitchValuePath(switches::kNaClGdbScript).empty());
 332   UMA_HISTOGRAM_BOOLEAN(
 333       "NaCl.enable-nacl-debug",
 334       cmd->HasSwitch(switches::kEnableNaClDebug));
 335   std::string nacl_debug_mask =
 336       cmd->GetSwitchValueASCII(switches::kNaClDebugMask);
 337   // By default, exclude debugging SSH and the PNaCl translator.
 338   // about::flags only allows empty flags as the default, so replace
 339   // the empty setting with the default. To debug all apps, use a wild-card.
 340   if (nacl_debug_mask.empty()) {
 341     nacl_debug_mask = "!*://*/*ssh_client.nmf,chrome://pnacl-translator/*";
 342   }
 343   NaClBrowser::GetDelegate()->SetDebugPatterns(nacl_debug_mask);
 344 }
 345
 346 // static
 347 void NaClProcessHost::SetPpapiKeepAliveThrottleForTesting(
 348     unsigned milliseconds) {
 349   keepalive_throttle_interval_milliseconds_ = milliseconds;
 350 }
 351
 352 void NaClProcessHost::Launch(
 353     NaClHostMessageFilter* nacl_host_message_filter,
 354     IPC::Message* reply_msg,
 355     const base::FilePath& manifest_path) {
 356   nacl_host_message_filter_ = nacl_host_message_filter;
 357   reply_msg_ = reply_msg;
 358   manifest_path_ = manifest_path;
 359
 360   // Do not launch the requested NaCl module if NaCl is marked "unstable" due
 361   // to too many crashes within a given time period.
 362   if (enable_crash_throttling_ &&
 363       !CommandLine::ForCurrentProcess()->HasSwitch(
 364           switches::kDisablePnaclCrashThrottling) &&
 365       NaClBrowser::GetInstance()->IsThrottled()) {
 366     SendErrorToRenderer("Process creation was throttled due to excessive"
 367                         " crashes");
 368     delete this;
 369     return;
 370   }
 371
 372   const CommandLine* cmd = CommandLine::ForCurrentProcess();
 373 #if defined(OS_WIN)
 374   if (cmd->HasSwitch(switches::kEnableNaClDebug) &&
 375       !cmd->HasSwitch(switches::kNoSandbox)) {
 376     // We don't switch off sandbox automatically for security reasons.
 377     SendErrorToRenderer("NaCl's GDB debug stub requires --no-sandbox flag"
 378                         " on Windows. See crbug.com/265624.");
 379     delete this;
 380     return;
 381   }
 382 #endif
 383   if (cmd->HasSwitch(switches::kNaClGdb) &&
 384       !cmd->HasSwitch(switches::kEnableNaClDebug)) {
 385     LOG(WARNING) << "--nacl-gdb flag requires --enable-nacl-debug flag";
 386   }
 387
 388   // Start getting the IRT open asynchronously while we launch the NaCl process.
 389   // We'll make sure this actually finished in StartWithLaunchedProcess, below.
 390   NaClBrowser* nacl_browser = NaClBrowser::GetInstance();
 391   nacl_browser->EnsureAllResourcesAvailable();
 392   if (!nacl_browser->IsOk()) {
 393     SendErrorToRenderer("could not find all the resources needed"
 394                         " to launch the process");
 395     delete this;
 396     return;
 397   }
 398
 399   if (uses_nonsfi_mode_) {
 400     bool nonsfi_mode_forced_by_command_line = false;
 401     bool nonsfi_mode_allowed = false;
 402 #if defined(OS_LINUX)
 403     nonsfi_mode_forced_by_command_line =
 404         cmd->HasSwitch(switches::kEnableNaClNonSfiMode);
 405 #if defined(OS_CHROMEOS) && defined(ARCH_CPU_ARMEL)
 406     nonsfi_mode_allowed = NaClBrowser::GetDelegate()->IsNonSfiModeAllowed(
 407         nacl_host_message_filter->profile_directory(), manifest_url_);
 408 #endif
 409 #endif
 410     bool nonsfi_mode_enabled =
 411         nonsfi_mode_forced_by_command_line || nonsfi_mode_allowed;
 412
 413     if (!nonsfi_mode_enabled) {
 414       SendErrorToRenderer(
 415           "NaCl non-SFI mode is not available for this platform"
 416           " and NaCl module.");
 417       delete this;
 418       return;
 419     }
 420   } else {
 421     // Rather than creating a socket pair in the renderer, and passing
 422     // one side through the browser to sel_ldr, socket pairs are created
 423     // in the browser and then passed to the renderer and sel_ldr.
 424     //
 425     // This is mainly for the benefit of Windows, where sockets cannot
 426     // be passed in messages, but are copied via DuplicateHandle().
 427     // This means the sandboxed renderer cannot send handles to the
 428     // browser process.
 429
 430     NaClHandle pair[2];
 431     // Create a connected socket
 432     if (NaClSocketPair(pair) == -1) {
 433       SendErrorToRenderer("NaClSocketPair() failed");
 434       delete this;
 435       return;
 436     }
 437     socket_for_renderer_ = base::File(pair[0]);
 438     socket_for_sel_ldr_ = base::File(pair[1]);
 439     SetCloseOnExec(pair[0]);
 440     SetCloseOnExec(pair[1]);
 441   }
 442
 443   // Create a shared memory region that the renderer and plugin share for
 444   // reporting crash information.
 445   crash_info_shmem_.CreateAnonymous(kNaClCrashInfoShmemSize);
 446
 447   // Launch the process
 448   if (!LaunchSelLdr()) {
 449     delete this;
 450   }
 451 }
 452
 453 void NaClProcessHost::OnChannelConnected(int32 peer_pid) {
 454   if (!CommandLine::ForCurrentProcess()->GetSwitchValuePath(
 455           switches::kNaClGdb).empty()) {
 456     LaunchNaClGdb();
 457   }
 458 }
 459
 460 #if defined(OS_WIN)
 461 void NaClProcessHost::OnProcessLaunchedByBroker(base::ProcessHandle handle) {
 462   process_launched_by_broker_ = true;
 463   process_->SetHandle(handle);
 464   SetDebugStubPort(nacl::kGdbDebugStubPortUnknown);
 465   if (!StartWithLaunchedProcess())
 466     delete this;
 467 }
 468
 469 void NaClProcessHost::OnDebugExceptionHandlerLaunchedByBroker(bool success) {
 470   IPC::Message* reply = attach_debug_exception_handler_reply_msg_.release();
 471   NaClProcessMsg_AttachDebugExceptionHandler::WriteReplyParams(reply, success);
 472   Send(reply);
 473 }
 474 #endif
 475
 476 // Needed to handle sync messages in OnMessageReceived.
 477 bool NaClProcessHost::Send(IPC::Message* msg) {
 478   return process_->Send(msg);
 479 }
 480
 481 bool NaClProcessHost::LaunchNaClGdb() {
 482 #if defined(OS_WIN)
 483   base::FilePath nacl_gdb =
 484       CommandLine::ForCurrentProcess()->GetSwitchValuePath(switches::kNaClGdb);
 485   CommandLine cmd_line(nacl_gdb);
 486 #else
 487   CommandLine::StringType nacl_gdb =
 488       CommandLine::ForCurrentProcess()->GetSwitchValueNative(
 489           switches::kNaClGdb);
 490   CommandLine::StringVector argv;
 491   // We don't support spaces inside arguments in --nacl-gdb switch.
 492   base::SplitString(nacl_gdb, static_cast<CommandLine::CharType>(' '), &argv);
 493   CommandLine cmd_line(argv);
 494 #endif
 495   cmd_line.AppendArg("--eval-command");
 496   base::FilePath::StringType irt_path(
 497       NaClBrowser::GetInstance()->GetIrtFilePath().value());
 498   // Avoid back slashes because nacl-gdb uses posix escaping rules on Windows.
 499   // See issue https://code.google.com/p/nativeclient/issues/detail?id=3482.
 500   std::replace(irt_path.begin(), irt_path.end(), '\\', '/');
 501   cmd_line.AppendArgNative(FILE_PATH_LITERAL("nacl-irt \"") + irt_path +
 502                            FILE_PATH_LITERAL("\""));
 503   if (!manifest_path_.empty()) {
 504     cmd_line.AppendArg("--eval-command");
 505     base::FilePath::StringType manifest_path_value(manifest_path_.value());
 506     std::replace(manifest_path_value.begin(), manifest_path_value.end(),
 507                  '\\', '/');
 508     cmd_line.AppendArgNative(FILE_PATH_LITERAL("nacl-manifest \"") +
 509                              manifest_path_value + FILE_PATH_LITERAL("\""));
 510   }
 511   cmd_line.AppendArg("--eval-command");
 512   cmd_line.AppendArg("target remote :4014");
 513   base::FilePath script = CommandLine::ForCurrentProcess()->GetSwitchValuePath(
 514       switches::kNaClGdbScript);
 515   if (!script.empty()) {
 516     cmd_line.AppendArg("--command");
 517     cmd_line.AppendArgNative(script.value());
 518   }
 519   return base::LaunchProcess(cmd_line, base::LaunchOptions(), NULL);
 520 }
 521
 522 bool NaClProcessHost::LaunchSelLdr() {
 523   std::string channel_id = process_->GetHost()->CreateChannel();
 524   if (channel_id.empty()) {
 525     SendErrorToRenderer("CreateChannel() failed");
 526     return false;
 527   }
 528
 529   // Build command line for nacl.
 530
 531 #if defined(OS_MACOSX)
 532   // The Native Client process needs to be able to allocate a 1GB contiguous
 533   // region to use as the client environment's virtual address space. ASLR
 534   // (PIE) interferes with this by making it possible that no gap large enough
 535   // to accomodate this request will exist in the child process' address
 536   // space. Disable PIE for NaCl processes. See http://crbug.com/90221 and
 537   // http://code.google.com/p/nativeclient/issues/detail?id=2043.
 538   int flags = ChildProcessHost::CHILD_NO_PIE;
 539 #elif defined(OS_LINUX)
 540   int flags = ChildProcessHost::CHILD_ALLOW_SELF;
 541 #else
 542   int flags = ChildProcessHost::CHILD_NORMAL;
 543 #endif
 544
 545   base::FilePath exe_path = ChildProcessHost::GetChildPath(flags);
 546   if (exe_path.empty())
 547     return false;
 548
 549 #if defined(OS_WIN)
 550   // On Windows 64-bit NaCl loader is called nacl64.exe instead of chrome.exe
 551   if (RunningOnWOW64()) {
 552     if (!NaClBrowser::GetInstance()->GetNaCl64ExePath(&exe_path)) {
 553       SendErrorToRenderer("could not get path to nacl64.exe");
 554       return false;
 555     }
 556
 557 #ifdef _DLL
 558     // When using the DLL CRT on Windows, we need to amend the PATH to include
 559     // the location of the x64 CRT DLLs. This is only the case when using a
 560     // component=shared_library build (i.e. generally dev debug builds). The
 561     // x86 CRT DLLs are in e.g. out\Debug for chrome.exe etc., so the x64 ones
 562     // are put in out\Debug\x64 which we add to the PATH here so that loader
 563     // can find them. See http://crbug.com/346034.
 564     scoped_ptr<base::Environment> env(base::Environment::Create());
 565     static const char kPath[] = "PATH";
 566     std::string old_path;
 567     base::FilePath module_path;
 568     if (!PathService::Get(base::FILE_MODULE, &module_path)) {
 569       SendErrorToRenderer("could not get path to current module");
 570       return false;
 571     }
 572     std::string x64_crt_path =
 573         base::WideToUTF8(module_path.DirName().Append(L"x64").value());
 574     if (!env->GetVar(kPath, &old_path)) {
 575       env->SetVar(kPath, x64_crt_path);
 576     } else if (!IsInPath(old_path, x64_crt_path)) {
 577       std::string new_path(old_path);
 578       new_path.append(";");
 579       new_path.append(x64_crt_path);
 580       env->SetVar(kPath, new_path);
 581     }
 582 #endif  // _DLL
 583   }
 584 #endif
 585
 586   scoped_ptr<CommandLine> cmd_line(new CommandLine(exe_path));
 587   CopyNaClCommandLineArguments(cmd_line.get());
 588
 589   cmd_line->AppendSwitchASCII(switches::kProcessType,
 590                               (uses_nonsfi_mode_ ?
 591                                switches::kNaClLoaderNonSfiProcess :
 592                                switches::kNaClLoaderProcess));
 593   cmd_line->AppendSwitchASCII(switches::kProcessChannelID, channel_id);
 594   if (NaClBrowser::GetDelegate()->DialogsAreSuppressed())
 595     cmd_line->AppendSwitch(switches::kNoErrorDialogs);
 596
 597   // On Windows we might need to start the broker process to launch a new loader
 598 #if defined(OS_WIN)
 599   if (RunningOnWOW64()) {
 600     if (!NaClBrokerService::GetInstance()->LaunchLoader(
 601             weak_factory_.GetWeakPtr(), channel_id)) {
 602       SendErrorToRenderer("broker service did not launch process");
 603       return false;
 604     }
 605     return true;
 606   }
 607 #endif
 608   process_->Launch(
 609       new NaClSandboxedProcessLauncherDelegate(process_->GetHost()),
 610       cmd_line.release());
 611   return true;
 612 }
 613
 614 bool NaClProcessHost::OnMessageReceived(const IPC::Message& msg) {
 615   bool handled = true;
 616   if (uses_nonsfi_mode_) {
 617     // IPC messages relating to NaCl's validation cache must not be exposed
 618     // in Non-SFI Mode, otherwise a Non-SFI nexe could use
 619     // SetKnownToValidate to create a hole in the SFI sandbox.
 620     IPC_BEGIN_MESSAGE_MAP(NaClProcessHost, msg)
 621       IPC_MESSAGE_HANDLER(NaClProcessHostMsg_PpapiChannelsCreated,
 622                           OnPpapiChannelsCreated)
 623       IPC_MESSAGE_UNHANDLED(handled = false)
 624     IPC_END_MESSAGE_MAP()
 625   } else {
 626     IPC_BEGIN_MESSAGE_MAP(NaClProcessHost, msg)
 627       IPC_MESSAGE_HANDLER(NaClProcessMsg_QueryKnownToValidate,
 628                           OnQueryKnownToValidate)
 629       IPC_MESSAGE_HANDLER(NaClProcessMsg_SetKnownToValidate,
 630                           OnSetKnownToValidate)
 631       IPC_MESSAGE_HANDLER_DELAY_REPLY(NaClProcessMsg_ResolveFileToken,
 632                                       OnResolveFileToken)
 633       IPC_MESSAGE_HANDLER(NaClProcessMsg_ResolveFileTokenAsync,
 634                           OnResolveFileTokenAsync)
 635
 636 #if defined(OS_WIN)
 637       IPC_MESSAGE_HANDLER_DELAY_REPLY(
 638           NaClProcessMsg_AttachDebugExceptionHandler,
 639           OnAttachDebugExceptionHandler)
 640       IPC_MESSAGE_HANDLER(NaClProcessHostMsg_DebugStubPortSelected,
 641                           OnDebugStubPortSelected)
 642 #endif
 643       IPC_MESSAGE_HANDLER(NaClProcessHostMsg_PpapiChannelsCreated,
 644                           OnPpapiChannelsCreated)
 645       IPC_MESSAGE_UNHANDLED(handled = false)
 646     IPC_END_MESSAGE_MAP()
 647   }
 648   return handled;
 649 }
 650
 651 void NaClProcessHost::OnProcessLaunched() {
 652   if (!StartWithLaunchedProcess())
 653     delete this;
 654 }
 655
 656 // Called when the NaClBrowser singleton has been fully initialized.
 657 void NaClProcessHost::OnResourcesReady() {
 658   NaClBrowser* nacl_browser = NaClBrowser::GetInstance();
 659   if (!nacl_browser->IsReady()) {
 660     SendErrorToRenderer("could not acquire shared resources needed by NaCl");
 661     delete this;
 662   } else if (!StartNaClExecution()) {
 663     delete this;
 664   }
 665 }
 666
 667 bool NaClProcessHost::ReplyToRenderer(
 668     const IPC::ChannelHandle& ppapi_channel_handle,
 669     const IPC::ChannelHandle& trusted_channel_handle,
 670     const IPC::ChannelHandle& manifest_service_channel_handle) {
 671 #if defined(OS_WIN)
 672   // If we are on 64-bit Windows, the NaCl process's sandbox is
 673   // managed by a different process from the renderer's sandbox.  We
 674   // need to inform the renderer's sandbox about the NaCl process so
 675   // that the renderer can send handles to the NaCl process using
 676   // BrokerDuplicateHandle().
 677   if (RunningOnWOW64()) {
 678     if (!content::BrokerAddTargetPeer(process_->GetData().handle)) {
 679       SendErrorToRenderer("BrokerAddTargetPeer() failed");
 680       return false;
 681     }
 682   }
 683 #endif
 684
 685   FileDescriptor imc_handle_for_renderer;
 686 #if defined(OS_WIN)
 687   // Copy the handle into the renderer process.
 688   HANDLE handle_in_renderer;
 689   if (!DuplicateHandle(base::GetCurrentProcessHandle(),
 690                        socket_for_renderer_.TakePlatformFile(),
 691                        nacl_host_message_filter_->PeerHandle(),
 692                        &handle_in_renderer,
 693                        0,  // Unused given DUPLICATE_SAME_ACCESS.
 694                        FALSE,
 695                        DUPLICATE_CLOSE_SOURCE | DUPLICATE_SAME_ACCESS)) {
 696     SendErrorToRenderer("DuplicateHandle() failed");
 697     return false;
 698   }
 699   imc_handle_for_renderer = reinterpret_cast<FileDescriptor>(
 700       handle_in_renderer);
 701 #else
 702   // No need to dup the imc_handle - we don't pass it anywhere else so
 703   // it cannot be closed.
 704   FileDescriptor imc_handle;
 705   imc_handle.fd = socket_for_renderer_.TakePlatformFile();
 706   imc_handle.auto_close = true;
 707   imc_handle_for_renderer = imc_handle;
 708 #endif
 709
 710   const ChildProcessData& data = process_->GetData();
 711   base::SharedMemoryHandle crash_info_shmem_renderer_handle;
 712   if (!crash_info_shmem_.ShareToProcess(nacl_host_message_filter_->PeerHandle(),
 713                                         &crash_info_shmem_renderer_handle)) {
 714     SendErrorToRenderer("ShareToProcess() failed");
 715     return false;
 716   }
 717
 718   SendMessageToRenderer(
 719       NaClLaunchResult(imc_handle_for_renderer,
 720                        ppapi_channel_handle,
 721                        trusted_channel_handle,
 722                        manifest_service_channel_handle,
 723                        base::GetProcId(data.handle),
 724                        data.id,
 725                        crash_info_shmem_renderer_handle),
 726       std::string() /* error_message */);
 727
 728   // Now that the crash information shmem handles have been shared with the
 729   // plugin and the renderer, the browser can close its handle.
 730   crash_info_shmem_.Close();
 731   return true;
 732 }
 733
 734 void NaClProcessHost::SendErrorToRenderer(const std::string& error_message) {
 735   LOG(ERROR) << "NaCl process launch failed: " << error_message;
 736   SendMessageToRenderer(NaClLaunchResult(), error_message);
 737 }
 738
 739 void NaClProcessHost::SendMessageToRenderer(
 740     const NaClLaunchResult& result,
 741     const std::string& error_message) {
 742   DCHECK(nacl_host_message_filter_.get());
 743   DCHECK(reply_msg_);
 744   if (nacl_host_message_filter_.get() != NULL && reply_msg_ != NULL) {
 745     NaClHostMsg_LaunchNaCl::WriteReplyParams(
 746         reply_msg_, result, error_message);
 747     nacl_host_message_filter_->Send(reply_msg_);
 748     nacl_host_message_filter_ = NULL;
 749     reply_msg_ = NULL;
 750   }
 751 }
 752
 753 void NaClProcessHost::SetDebugStubPort(int port) {
 754   NaClBrowser* nacl_browser = NaClBrowser::GetInstance();
 755   nacl_browser->SetProcessGdbDebugStubPort(process_->GetData().id, port);
 756 }
 757
 758 #if defined(OS_POSIX)
 759 // TCP port we chose for NaCl debug stub. It can be any other number.
 760 static const int kInitialDebugStubPort = 4014;
 761
 762 net::SocketDescriptor NaClProcessHost::GetDebugStubSocketHandle() {
 763   net::SocketDescriptor s = net::kInvalidSocket;
 764   // We always try to allocate the default port first. If this fails, we then
 765   // allocate any available port.
 766   // On success, if the test system has register a handler
 767   // (GdbDebugStubPortListener), we fire a notification.
 768   int port = kInitialDebugStubPort;
 769   s = net::TCPListenSocket::CreateAndBind("127.0.0.1", port);
 770   if (s == net::kInvalidSocket) {
 771     s = net::TCPListenSocket::CreateAndBindAnyPort("127.0.0.1", &port);
 772   }
 773   if (s != net::kInvalidSocket) {
 774     SetDebugStubPort(port);
 775   }
 776   if (s == net::kInvalidSocket) {
 777     LOG(ERROR) << "failed to open socket for debug stub";
 778     return net::kInvalidSocket;
 779   } else {
 780     LOG(WARNING) << "debug stub on port " << port;
 781   }
 782   if (listen(s, 1)) {
 783     LOG(ERROR) << "listen() failed on debug stub socket";
 784     if (IGNORE_EINTR(close(s)) < 0)
 785       PLOG(ERROR) << "failed to close debug stub socket";
 786     return net::kInvalidSocket;
 787   }
 788   return s;
 789 }
 790 #endif
 791
 792 #if defined(OS_WIN)
 793 void NaClProcessHost::OnDebugStubPortSelected(uint16_t debug_stub_port) {
 794   CHECK(!uses_nonsfi_mode_);
 795   SetDebugStubPort(debug_stub_port);
 796 }
 797 #endif
 798
 799 bool NaClProcessHost::StartNaClExecution() {
 800   NaClBrowser* nacl_browser = NaClBrowser::GetInstance();
 801
 802   NaClStartParams params;
 803
 804   // Enable PPAPI proxy channel creation only for renderer processes.
 805   params.enable_ipc_proxy = enable_ppapi_proxy();
 806   params.process_type = process_type_;
 807   if (uses_nonsfi_mode_) {
 808     // Currently, non-SFI mode is supported only on Linux.
 809 #if defined(OS_LINUX)
 810     // In non-SFI mode, we do not use SRPC. Make sure that the socketpair is
 811     // not created.
 812     DCHECK(!socket_for_sel_ldr_.IsValid());
 813 #endif
 814   } else {
 815     params.validation_cache_enabled = nacl_browser->ValidationCacheIsEnabled();
 816     params.validation_cache_key = nacl_browser->GetValidationCacheKey();
 817     params.version = NaClBrowser::GetDelegate()->GetVersionString();
 818     params.enable_debug_stub = enable_debug_stub_ &&
 819         NaClBrowser::GetDelegate()->URLMatchesDebugPatterns(manifest_url_);
 820
 821     // TODO(teravest): Resolve the file tokens right now instead of making the
 822     // loader send IPC to resolve them later.
 823     params.nexe_token_lo = nexe_token_.lo;
 824     params.nexe_token_hi = nexe_token_.hi;
 825
 826     const ChildProcessData& data = process_->GetData();
 827     if (!ShareHandleToSelLdr(data.handle,
 828                              socket_for_sel_ldr_.TakePlatformFile(),
 829                              true,
 830                              &params.handles)) {
 831       return false;
 832     }
 833
 834     const base::File& irt_file = nacl_browser->IrtFile();
 835     CHECK(irt_file.IsValid());
 836     // Send over the IRT file handle.  We don't close our own copy!
 837     if (!ShareHandleToSelLdr(data.handle, irt_file.GetPlatformFile(), false,
 838                              &params.handles)) {
 839       return false;
 840     }
 841
 842 #if defined(OS_MACOSX)
 843     // For dynamic loading support, NaCl requires a file descriptor that
 844     // was created in /tmp, since those created with shm_open() are not
 845     // mappable with PROT_EXEC.  Rather than requiring an extra IPC
 846     // round trip out of the sandbox, we create an FD here.
 847     base::SharedMemory memory_buffer;
 848     base::SharedMemoryCreateOptions options;
 849     options.size = 1;
 850     options.executable = true;
 851     if (!memory_buffer.Create(options)) {
 852       DLOG(ERROR) << "Failed to allocate memory buffer";
 853       return false;
 854     }
 855     FileDescriptor memory_fd;
 856     memory_fd.fd = dup(memory_buffer.handle().fd);
 857     if (memory_fd.fd < 0) {
 858       DLOG(ERROR) << "Failed to dup() a file descriptor";
 859       return false;
 860     }
 861     memory_fd.auto_close = true;
 862     params.handles.push_back(memory_fd);
 863 #endif
 864
 865 #if defined(OS_POSIX)
 866     if (params.enable_debug_stub) {
 867       net::SocketDescriptor server_bound_socket = GetDebugStubSocketHandle();
 868       if (server_bound_socket != net::kInvalidSocket) {
 869         params.debug_stub_server_bound_socket =
 870             FileDescriptor(server_bound_socket, true);
 871       }
 872     }
 873 #endif
 874   }
 875
 876   params.nexe_file = IPC::TakeFileHandleForProcess(nexe_file_.Pass(),
 877                                                    process_->GetData().handle);
 878   if (!crash_info_shmem_.ShareToProcess(process_->GetData().handle,
 879                                         &params.crash_info_shmem_handle)) {
 880     DLOG(ERROR) << "Failed to ShareToProcess() a shared memory buffer";
 881     return false;
 882   }
 883
 884   process_->Send(new NaClProcessMsg_Start(params));
 885   return true;
 886 }
 887
 888 // This method is called when NaClProcessHostMsg_PpapiChannelCreated is
 889 // received.
 890 void NaClProcessHost::OnPpapiChannelsCreated(
 891     const IPC::ChannelHandle& browser_channel_handle,
 892     const IPC::ChannelHandle& ppapi_renderer_channel_handle,
 893     const IPC::ChannelHandle& trusted_renderer_channel_handle,
 894     const IPC::ChannelHandle& manifest_service_channel_handle) {
 895   if (!enable_ppapi_proxy()) {
 896     ReplyToRenderer(IPC::ChannelHandle(),
 897                     trusted_renderer_channel_handle,
 898                     manifest_service_channel_handle);
 899     return;
 900   }
 901
 902   if (!ipc_proxy_channel_.get()) {
 903     DCHECK_EQ(PROCESS_TYPE_NACL_LOADER, process_->GetData().process_type);
 904
 905     ipc_proxy_channel_ =
 906         IPC::ChannelProxy::Create(browser_channel_handle,
 907                                   IPC::Channel::MODE_CLIENT,
 908                                   NULL,
 909                                   base::MessageLoopProxy::current().get());
 910     // Create the browser ppapi host and enable PPAPI message dispatching to the
 911     // browser process.
 912     ppapi_host_.reset(content::BrowserPpapiHost::CreateExternalPluginProcess(
 913         ipc_proxy_channel_.get(),  // sender
 914         permissions_,
 915         process_->GetData().handle,
 916         ipc_proxy_channel_.get(),
 917         nacl_host_message_filter_->render_process_id(),
 918         render_view_id_,
 919         profile_directory_));
 920     ppapi_host_->SetOnKeepaliveCallback(
 921         NaClBrowser::GetDelegate()->GetOnKeepaliveCallback());
 922
 923     ppapi::PpapiNaClPluginArgs args;
 924     args.off_the_record = nacl_host_message_filter_->off_the_record();
 925     args.permissions = permissions_;
 926     args.keepalive_throttle_interval_milliseconds =
 927         keepalive_throttle_interval_milliseconds_;
 928     CommandLine* cmdline = CommandLine::ForCurrentProcess();
 929     DCHECK(cmdline);
 930     std::string flag_whitelist[] = {
 931       switches::kV,
 932       switches::kVModule,
 933     };
 934     for (size_t i = 0; i < arraysize(flag_whitelist); ++i) {
 935       std::string value = cmdline->GetSwitchValueASCII(flag_whitelist[i]);
 936       if (!value.empty()) {
 937         args.switch_names.push_back(flag_whitelist[i]);
 938         args.switch_values.push_back(value);
 939       }
 940     }
 941
 942     ppapi_host_->GetPpapiHost()->AddHostFactoryFilter(
 943         scoped_ptr<ppapi::host::HostFactory>(
 944             NaClBrowser::GetDelegate()->CreatePpapiHostFactory(
 945                 ppapi_host_.get())));
 946
 947     // Send a message to initialize the IPC dispatchers in the NaCl plugin.
 948     ipc_proxy_channel_->Send(new PpapiMsg_InitializeNaClDispatcher(args));
 949
 950     // Let the renderer know that the IPC channels are established.
 951     ReplyToRenderer(ppapi_renderer_channel_handle,
 952                     trusted_renderer_channel_handle,
 953                     manifest_service_channel_handle);
 954   } else {
 955     // Attempt to open more than 1 browser channel is not supported.
 956     // Shut down the NaCl process.
 957     process_->GetHost()->ForceShutdown();
 958   }
 959 }
 960
 961 bool NaClProcessHost::StartWithLaunchedProcess() {
 962   NaClBrowser* nacl_browser = NaClBrowser::GetInstance();
 963
 964   if (nacl_browser->IsReady()) {
 965     return StartNaClExecution();
 966   } else if (nacl_browser->IsOk()) {
 967     nacl_browser->WaitForResources(
 968         base::Bind(&NaClProcessHost::OnResourcesReady,
 969                    weak_factory_.GetWeakPtr()));
 970     return true;
 971   } else {
 972     SendErrorToRenderer("previously failed to acquire shared resources");
 973     return false;
 974   }
 975 }
 976
 977 void NaClProcessHost::OnQueryKnownToValidate(const std::string& signature,
 978                                              bool* result) {
 979   CHECK(!uses_nonsfi_mode_);
 980   NaClBrowser* nacl_browser = NaClBrowser::GetInstance();
 981   *result = nacl_browser->QueryKnownToValidate(signature, off_the_record_);
 982 }
 983
 984 void NaClProcessHost::OnSetKnownToValidate(const std::string& signature) {
 985   CHECK(!uses_nonsfi_mode_);
 986   NaClBrowser::GetInstance()->SetKnownToValidate(
 987       signature, off_the_record_);
 988 }
 989
 990 void NaClProcessHost::OnResolveFileToken(uint64 file_token_lo,
 991                                          uint64 file_token_hi,
 992                                          IPC::Message* reply_msg) {
 993   // Was the file registered?
 994   //
 995   // Note that the file path cache is of bounded size, and old entries can get
 996   // evicted.  If a large number of NaCl modules are being launched at once,
 997   // resolving the file_token may fail because the path cache was thrashed
 998   // while the file_token was in flight.  In this case the query fails, and we
 999   // need to fall back to the slower path.
1000   //
1001   // However: each NaCl process will consume 2-3 entries as it starts up, this
1002   // means that eviction will not happen unless you start up 33+ NaCl processes
1003   // at the same time, and this still requires worst-case timing.  As a
1004   // practical matter, no entries should be evicted prematurely.
1005   // The cache itself should take ~ (150 characters * 2 bytes/char + ~60 bytes
1006   // data structure overhead) * 100 = 35k when full, so making it bigger should
1007   // not be a problem, if needed.
1008   //
1009   // Each NaCl process will consume 2-3 entries because the manifest and main
1010   // nexe are currently not resolved.  Shared libraries will be resolved.  They
1011   // will be loaded sequentially, so they will only consume a single entry
1012   // while the load is in flight.
1013   //
1014   // TODO(ncbray): track behavior with UMA. If entries are getting evicted or
1015   // bogus keys are getting queried, this would be good to know.
1016   CHECK(!uses_nonsfi_mode_);
1017   base::FilePath file_path;
1018   if (!NaClBrowser::GetInstance()->GetFilePath(
1019         file_token_lo, file_token_hi, &file_path)) {
1020     NaClProcessMsg_ResolveFileToken::WriteReplyParams(
1021         reply_msg,
1022         IPC::InvalidPlatformFileForTransit(),
1023         base::FilePath());
1024     Send(reply_msg);
1025     return;
1026   }
1027
1028   // Open the file.
1029   if (!base::PostTaskAndReplyWithResult(
1030           content::BrowserThread::GetBlockingPool(),
1031           FROM_HERE,
1032           base::Bind(OpenNaClReadExecImpl, file_path, true /* is_executable */),
1033           base::Bind(&NaClProcessHost::FileResolved,
1034                      weak_factory_.GetWeakPtr(),
1035                      file_path,
1036                      reply_msg))) {
1037      NaClProcessMsg_ResolveFileToken::WriteReplyParams(
1038          reply_msg,
1039          IPC::InvalidPlatformFileForTransit(),
1040          base::FilePath());
1041      Send(reply_msg);
1042   }
1043 }
1044
1045 void NaClProcessHost::OnResolveFileTokenAsync(uint64 file_token_lo,
1046                                               uint64 file_token_hi) {
1047   // See the comment at OnResolveFileToken() for details of the file path cache
1048   // behavior.
1049   CHECK(!uses_nonsfi_mode_);
1050   base::FilePath file_path;
1051   if (!NaClBrowser::GetInstance()->GetFilePath(
1052         file_token_lo, file_token_hi, &file_path)) {
1053     Send(new NaClProcessMsg_ResolveFileTokenAsyncReply(
1054              file_token_lo,
1055              file_token_hi,
1056              IPC::PlatformFileForTransit(),
1057              base::FilePath()));
1058     return;
1059   }
1060
1061   // Open the file.
1062   if (!base::PostTaskAndReplyWithResult(
1063           content::BrowserThread::GetBlockingPool(),
1064           FROM_HERE,
1065           base::Bind(OpenNaClReadExecImpl, file_path, true /* is_executable */),
1066           base::Bind(&NaClProcessHost::FileResolvedAsync,
1067                      weak_factory_.GetWeakPtr(),
1068                      file_token_lo,
1069                      file_token_hi,
1070                      file_path))) {
1071     Send(new NaClProcessMsg_ResolveFileTokenAsyncReply(
1072             file_token_lo,
1073             file_token_hi,
1074             IPC::PlatformFileForTransit(),
1075             base::FilePath()));
1076   }
1077 }
1078
1079 void NaClProcessHost::FileResolved(
1080     const base::FilePath& file_path,
1081     IPC::Message* reply_msg,
1082     base::File file) {
1083   if (file.IsValid()) {
1084     IPC::PlatformFileForTransit handle = IPC::TakeFileHandleForProcess(
1085         file.Pass(),
1086         process_->GetData().handle);
1087     NaClProcessMsg_ResolveFileToken::WriteReplyParams(
1088         reply_msg,
1089         handle,
1090         file_path);
1091   } else {
1092     NaClProcessMsg_ResolveFileToken::WriteReplyParams(
1093         reply_msg,
1094         IPC::InvalidPlatformFileForTransit(),
1095         base::FilePath());
1096   }
1097   Send(reply_msg);
1098 }
1099
1100 void NaClProcessHost::FileResolvedAsync(
1101     uint64_t file_token_lo,
1102     uint64_t file_token_hi,
1103     const base::FilePath& file_path,
1104     base::File file) {
1105   base::FilePath out_file_path;
1106   IPC::PlatformFileForTransit out_handle;
1107   if (file.IsValid()) {
1108     out_file_path = file_path;
1109     out_handle = IPC::TakeFileHandleForProcess(
1110         file.Pass(),
1111         process_->GetData().handle);
1112   } else {
1113     out_handle = IPC::InvalidPlatformFileForTransit();
1114   }
1115   Send(new NaClProcessMsg_ResolveFileTokenAsyncReply(
1116            file_token_lo,
1117            file_token_hi,
1118            out_handle,
1119            out_file_path));
1120 }
1121
1122 #if defined(OS_WIN)
1123 void NaClProcessHost::OnAttachDebugExceptionHandler(const std::string& info,
1124                                                     IPC::Message* reply_msg) {
1125   CHECK(!uses_nonsfi_mode_);
1126   if (!AttachDebugExceptionHandler(info, reply_msg)) {
1127     // Send failure message.
1128     NaClProcessMsg_AttachDebugExceptionHandler::WriteReplyParams(reply_msg,
1129                                                                  false);
1130     Send(reply_msg);
1131   }
1132 }
1133
1134 bool NaClProcessHost::AttachDebugExceptionHandler(const std::string& info,
1135                                                   IPC::Message* reply_msg) {
1136   bool enable_exception_handling = process_type_ == kNativeNaClProcessType;
1137   if (!enable_exception_handling && !enable_debug_stub_) {
1138     DLOG(ERROR) <<
1139         "Debug exception handler requested by NaCl process when not enabled";
1140     return false;
1141   }
1142   if (debug_exception_handler_requested_) {
1143     // The NaCl process should not request this multiple times.
1144     DLOG(ERROR) << "Multiple AttachDebugExceptionHandler requests received";
1145     return false;
1146   }
1147   debug_exception_handler_requested_ = true;
1148
1149   base::ProcessId nacl_pid = base::GetProcId(process_->GetData().handle);
1150   base::ProcessHandle temp_handle;
1151   // We cannot use process_->GetData().handle because it does not have
1152   // the necessary access rights.  We open the new handle here rather
1153   // than in the NaCl broker process in case the NaCl loader process
1154   // dies before the NaCl broker process receives the message we send.
1155   // The debug exception handler uses DebugActiveProcess() to attach,
1156   // but this takes a PID.  We need to prevent the NaCl loader's PID
1157   // from being reused before DebugActiveProcess() is called, and
1158   // holding a process handle open achieves this.
1159   if (!base::OpenProcessHandleWithAccess(
1160            nacl_pid,
1161            base::kProcessAccessQueryInformation |
1162            base::kProcessAccessSuspendResume |
1163            base::kProcessAccessTerminate |
1164            base::kProcessAccessVMOperation |
1165            base::kProcessAccessVMRead |
1166            base::kProcessAccessVMWrite |
1167            base::kProcessAccessDuplicateHandle |
1168            base::kProcessAccessWaitForTermination,
1169            &temp_handle)) {
1170     LOG(ERROR) << "Failed to get process handle";
1171     return false;
1172   }
1173   base::win::ScopedHandle process_handle(temp_handle);
1174
1175   attach_debug_exception_handler_reply_msg_.reset(reply_msg);
1176   // If the NaCl loader is 64-bit, the process running its debug
1177   // exception handler must be 64-bit too, so we use the 64-bit NaCl
1178   // broker process for this.  Otherwise, on a 32-bit system, we use
1179   // the 32-bit browser process to run the debug exception handler.
1180   if (RunningOnWOW64()) {
1181     return NaClBrokerService::GetInstance()->LaunchDebugExceptionHandler(
1182                weak_factory_.GetWeakPtr(), nacl_pid, process_handle.Get(),
1183                info);
1184   } else {
1185     NaClStartDebugExceptionHandlerThread(
1186         process_handle.Take(), info,
1187         base::MessageLoopProxy::current(),
1188         base::Bind(&NaClProcessHost::OnDebugExceptionHandlerLaunchedByBroker,
1189                    weak_factory_.GetWeakPtr()));
1190     return true;
1191   }
1192 }
1193 #endif
1194
1195 }  // namespace nacl