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 void CloseFile(base::File file) {
 230   // The base::File destructor will close the file for us.
 231 }
 232
 233 }  // namespace
 234
 235 unsigned NaClProcessHost::keepalive_throttle_interval_milliseconds_ =
 236     ppapi::kKeepaliveThrottleIntervalDefaultMilliseconds;
 237
 238 NaClProcessHost::NaClProcessHost(const GURL& manifest_url,
 239                                  base::File nexe_file,
 240                                  const NaClFileToken& nexe_token,
 241                                  ppapi::PpapiPermissions permissions,
 242                                  int render_view_id,
 243                                  uint32 permission_bits,
 244                                  bool uses_nonsfi_mode,
 245                                  bool off_the_record,
 246                                  NaClAppProcessType process_type,
 247                                  const base::FilePath& profile_directory)
 248     : manifest_url_(manifest_url),
 249       nexe_file_(nexe_file.Pass()),
 250       nexe_token_(nexe_token),
 251       permissions_(permissions),
 252 #if defined(OS_WIN)
 253       process_launched_by_broker_(false),
 254 #endif
 255       reply_msg_(NULL),
 256 #if defined(OS_WIN)
 257       debug_exception_handler_requested_(false),
 258 #endif
 259       uses_nonsfi_mode_(uses_nonsfi_mode),
 260       enable_debug_stub_(false),
 261       enable_crash_throttling_(false),
 262       off_the_record_(off_the_record),
 263       process_type_(process_type),
 264       profile_directory_(profile_directory),
 265       render_view_id_(render_view_id),
 266       weak_factory_(this) {
 267   process_.reset(content::BrowserChildProcessHost::Create(
 268       PROCESS_TYPE_NACL_LOADER, this));
 269
 270   // Set the display name so the user knows what plugin the process is running.
 271   // We aren't on the UI thread so getting the pref locale for language
 272   // formatting isn't possible, so IDN will be lost, but this is probably OK
 273   // for this use case.
 274   process_->SetName(net::FormatUrl(manifest_url_, std::string()));
 275
 276   enable_debug_stub_ = CommandLine::ForCurrentProcess()->HasSwitch(
 277       switches::kEnableNaClDebug);
 278   DCHECK(process_type_ != kUnknownNaClProcessType);
 279   enable_crash_throttling_ = process_type_ != kNativeNaClProcessType;
 280 }
 281
 282 NaClProcessHost::~NaClProcessHost() {
 283   // Report exit status only if the process was successfully started.
 284   if (process_->GetData().handle != base::kNullProcessHandle) {
 285     int exit_code = 0;
 286     process_->GetTerminationStatus(false /* known_dead */, &exit_code);
 287     std::string message =
 288         base::StringPrintf("NaCl process exited with status %i (0x%x)",
 289                            exit_code, exit_code);
 290     if (exit_code == 0) {
 291       VLOG(1) << message;
 292     } else {
 293       LOG(ERROR) << message;
 294     }
 295     NaClBrowser::GetInstance()->OnProcessEnd(process_->GetData().id);
 296   }
 297
 298   if (reply_msg_) {
 299     // The process failed to launch for some reason.
 300     // Don't keep the renderer hanging.
 301     reply_msg_->set_reply_error();
 302     nacl_host_message_filter_->Send(reply_msg_);
 303   }
 304 #if defined(OS_WIN)
 305   if (process_launched_by_broker_) {
 306     NaClBrokerService::GetInstance()->OnLoaderDied();
 307   }
 308 #endif
 309 }
 310
 311 void NaClProcessHost::OnProcessCrashed(int exit_status) {
 312   if (enable_crash_throttling_ &&
 313       !CommandLine::ForCurrentProcess()->HasSwitch(
 314           switches::kDisablePnaclCrashThrottling)) {
 315     NaClBrowser::GetInstance()->OnProcessCrashed();
 316   }
 317 }
 318
 319 // This is called at browser startup.
 320 // static
 321 void NaClProcessHost::EarlyStartup() {
 322   NaClBrowser::GetInstance()->EarlyStartup();
 323   // Inform NaClBrowser that we exist and will have a debug port at some point.
 324 #if defined(OS_LINUX) && !defined(OS_CHROMEOS)
 325   // Open the IRT file early to make sure that it isn't replaced out from
 326   // under us by autoupdate.
 327   NaClBrowser::GetInstance()->EnsureIrtAvailable();
 328 #endif
 329   CommandLine* cmd = CommandLine::ForCurrentProcess();
 330   UMA_HISTOGRAM_BOOLEAN(
 331       "NaCl.nacl-gdb",
 332       !cmd->GetSwitchValuePath(switches::kNaClGdb).empty());
 333   UMA_HISTOGRAM_BOOLEAN(
 334       "NaCl.nacl-gdb-script",
 335       !cmd->GetSwitchValuePath(switches::kNaClGdbScript).empty());
 336   UMA_HISTOGRAM_BOOLEAN(
 337       "NaCl.enable-nacl-debug",
 338       cmd->HasSwitch(switches::kEnableNaClDebug));
 339   std::string nacl_debug_mask =
 340       cmd->GetSwitchValueASCII(switches::kNaClDebugMask);
 341   // By default, exclude debugging SSH and the PNaCl translator.
 342   // about::flags only allows empty flags as the default, so replace
 343   // the empty setting with the default. To debug all apps, use a wild-card.
 344   if (nacl_debug_mask.empty()) {
 345     nacl_debug_mask = "!*://*/*ssh_client.nmf,chrome://pnacl-translator/*";
 346   }
 347   NaClBrowser::GetDelegate()->SetDebugPatterns(nacl_debug_mask);
 348 }
 349
 350 // static
 351 void NaClProcessHost::SetPpapiKeepAliveThrottleForTesting(
 352     unsigned milliseconds) {
 353   keepalive_throttle_interval_milliseconds_ = milliseconds;
 354 }
 355
 356 void NaClProcessHost::Launch(
 357     NaClHostMessageFilter* nacl_host_message_filter,
 358     IPC::Message* reply_msg,
 359     const base::FilePath& manifest_path) {
 360   nacl_host_message_filter_ = nacl_host_message_filter;
 361   reply_msg_ = reply_msg;
 362   manifest_path_ = manifest_path;
 363
 364   // Do not launch the requested NaCl module if NaCl is marked "unstable" due
 365   // to too many crashes within a given time period.
 366   if (enable_crash_throttling_ &&
 367       !CommandLine::ForCurrentProcess()->HasSwitch(
 368           switches::kDisablePnaclCrashThrottling) &&
 369       NaClBrowser::GetInstance()->IsThrottled()) {
 370     SendErrorToRenderer("Process creation was throttled due to excessive"
 371                         " crashes");
 372     delete this;
 373     return;
 374   }
 375
 376   const CommandLine* cmd = CommandLine::ForCurrentProcess();
 377 #if defined(OS_WIN)
 378   if (cmd->HasSwitch(switches::kEnableNaClDebug) &&
 379       !cmd->HasSwitch(switches::kNoSandbox)) {
 380     // We don't switch off sandbox automatically for security reasons.
 381     SendErrorToRenderer("NaCl's GDB debug stub requires --no-sandbox flag"
 382                         " on Windows. See crbug.com/265624.");
 383     delete this;
 384     return;
 385   }
 386 #endif
 387   if (cmd->HasSwitch(switches::kNaClGdb) &&
 388       !cmd->HasSwitch(switches::kEnableNaClDebug)) {
 389     LOG(WARNING) << "--nacl-gdb flag requires --enable-nacl-debug flag";
 390   }
 391
 392   // Start getting the IRT open asynchronously while we launch the NaCl process.
 393   // We'll make sure this actually finished in StartWithLaunchedProcess, below.
 394   NaClBrowser* nacl_browser = NaClBrowser::GetInstance();
 395   nacl_browser->EnsureAllResourcesAvailable();
 396   if (!nacl_browser->IsOk()) {
 397     SendErrorToRenderer("could not find all the resources needed"
 398                         " to launch the process");
 399     delete this;
 400     return;
 401   }
 402
 403   if (uses_nonsfi_mode_) {
 404     bool nonsfi_mode_forced_by_command_line = false;
 405     bool nonsfi_mode_allowed = false;
 406 #if defined(OS_LINUX)
 407     nonsfi_mode_forced_by_command_line =
 408         cmd->HasSwitch(switches::kEnableNaClNonSfiMode);
 409 #if defined(OS_CHROMEOS) && defined(ARCH_CPU_ARMEL)
 410     nonsfi_mode_allowed = NaClBrowser::GetDelegate()->IsNonSfiModeAllowed(
 411         nacl_host_message_filter->profile_directory(), manifest_url_);
 412 #endif
 413 #endif
 414     bool nonsfi_mode_enabled =
 415         nonsfi_mode_forced_by_command_line || nonsfi_mode_allowed;
 416
 417     if (!nonsfi_mode_enabled) {
 418       SendErrorToRenderer(
 419           "NaCl non-SFI mode is not available for this platform"
 420           " and NaCl module.");
 421       delete this;
 422       return;
 423     }
 424   } else {
 425     // Rather than creating a socket pair in the renderer, and passing
 426     // one side through the browser to sel_ldr, socket pairs are created
 427     // in the browser and then passed to the renderer and sel_ldr.
 428     //
 429     // This is mainly for the benefit of Windows, where sockets cannot
 430     // be passed in messages, but are copied via DuplicateHandle().
 431     // This means the sandboxed renderer cannot send handles to the
 432     // browser process.
 433
 434     NaClHandle pair[2];
 435     // Create a connected socket
 436     if (NaClSocketPair(pair) == -1) {
 437       SendErrorToRenderer("NaClSocketPair() failed");
 438       delete this;
 439       return;
 440     }
 441     socket_for_renderer_ = base::File(pair[0]);
 442     socket_for_sel_ldr_ = base::File(pair[1]);
 443     SetCloseOnExec(pair[0]);
 444     SetCloseOnExec(pair[1]);
 445   }
 446
 447   // Create a shared memory region that the renderer and plugin share for
 448   // reporting crash information.
 449   crash_info_shmem_.CreateAnonymous(kNaClCrashInfoShmemSize);
 450
 451   // Launch the process
 452   if (!LaunchSelLdr()) {
 453     delete this;
 454   }
 455 }
 456
 457 void NaClProcessHost::OnChannelConnected(int32 peer_pid) {
 458   if (!CommandLine::ForCurrentProcess()->GetSwitchValuePath(
 459           switches::kNaClGdb).empty()) {
 460     LaunchNaClGdb();
 461   }
 462 }
 463
 464 #if defined(OS_WIN)
 465 void NaClProcessHost::OnProcessLaunchedByBroker(base::ProcessHandle handle) {
 466   process_launched_by_broker_ = true;
 467   process_->SetHandle(handle);
 468   SetDebugStubPort(nacl::kGdbDebugStubPortUnknown);
 469   if (!StartWithLaunchedProcess())
 470     delete this;
 471 }
 472
 473 void NaClProcessHost::OnDebugExceptionHandlerLaunchedByBroker(bool success) {
 474   IPC::Message* reply = attach_debug_exception_handler_reply_msg_.release();
 475   NaClProcessMsg_AttachDebugExceptionHandler::WriteReplyParams(reply, success);
 476   Send(reply);
 477 }
 478 #endif
 479
 480 // Needed to handle sync messages in OnMessageReceived.
 481 bool NaClProcessHost::Send(IPC::Message* msg) {
 482   return process_->Send(msg);
 483 }
 484
 485 bool NaClProcessHost::LaunchNaClGdb() {
 486 #if defined(OS_WIN)
 487   base::FilePath nacl_gdb =
 488       CommandLine::ForCurrentProcess()->GetSwitchValuePath(switches::kNaClGdb);
 489   CommandLine cmd_line(nacl_gdb);
 490 #else
 491   CommandLine::StringType nacl_gdb =
 492       CommandLine::ForCurrentProcess()->GetSwitchValueNative(
 493           switches::kNaClGdb);
 494   CommandLine::StringVector argv;
 495   // We don't support spaces inside arguments in --nacl-gdb switch.
 496   base::SplitString(nacl_gdb, static_cast<CommandLine::CharType>(' '), &argv);
 497   CommandLine cmd_line(argv);
 498 #endif
 499   cmd_line.AppendArg("--eval-command");
 500   base::FilePath::StringType irt_path(
 501       NaClBrowser::GetInstance()->GetIrtFilePath().value());
 502   // Avoid back slashes because nacl-gdb uses posix escaping rules on Windows.
 503   // See issue https://code.google.com/p/nativeclient/issues/detail?id=3482.
 504   std::replace(irt_path.begin(), irt_path.end(), '\\', '/');
 505   cmd_line.AppendArgNative(FILE_PATH_LITERAL("nacl-irt \"") + irt_path +
 506                            FILE_PATH_LITERAL("\""));
 507   if (!manifest_path_.empty()) {
 508     cmd_line.AppendArg("--eval-command");
 509     base::FilePath::StringType manifest_path_value(manifest_path_.value());
 510     std::replace(manifest_path_value.begin(), manifest_path_value.end(),
 511                  '\\', '/');
 512     cmd_line.AppendArgNative(FILE_PATH_LITERAL("nacl-manifest \"") +
 513                              manifest_path_value + FILE_PATH_LITERAL("\""));
 514   }
 515   cmd_line.AppendArg("--eval-command");
 516   cmd_line.AppendArg("target remote :4014");
 517   base::FilePath script = CommandLine::ForCurrentProcess()->GetSwitchValuePath(
 518       switches::kNaClGdbScript);
 519   if (!script.empty()) {
 520     cmd_line.AppendArg("--command");
 521     cmd_line.AppendArgNative(script.value());
 522   }
 523   return base::LaunchProcess(cmd_line, base::LaunchOptions(), NULL);
 524 }
 525
 526 bool NaClProcessHost::LaunchSelLdr() {
 527   std::string channel_id = process_->GetHost()->CreateChannel();
 528   if (channel_id.empty()) {
 529     SendErrorToRenderer("CreateChannel() failed");
 530     return false;
 531   }
 532
 533   // Build command line for nacl.
 534
 535 #if defined(OS_MACOSX)
 536   // The Native Client process needs to be able to allocate a 1GB contiguous
 537   // region to use as the client environment's virtual address space. ASLR
 538   // (PIE) interferes with this by making it possible that no gap large enough
 539   // to accomodate this request will exist in the child process' address
 540   // space. Disable PIE for NaCl processes. See http://crbug.com/90221 and
 541   // http://code.google.com/p/nativeclient/issues/detail?id=2043.
 542   int flags = ChildProcessHost::CHILD_NO_PIE;
 543 #elif defined(OS_LINUX)
 544   int flags = ChildProcessHost::CHILD_ALLOW_SELF;
 545 #else
 546   int flags = ChildProcessHost::CHILD_NORMAL;
 547 #endif
 548
 549   base::FilePath exe_path = ChildProcessHost::GetChildPath(flags);
 550   if (exe_path.empty())
 551     return false;
 552
 553 #if defined(OS_WIN)
 554   // On Windows 64-bit NaCl loader is called nacl64.exe instead of chrome.exe
 555   if (RunningOnWOW64()) {
 556     if (!NaClBrowser::GetInstance()->GetNaCl64ExePath(&exe_path)) {
 557       SendErrorToRenderer("could not get path to nacl64.exe");
 558       return false;
 559     }
 560
 561 #ifdef _DLL
 562     // When using the DLL CRT on Windows, we need to amend the PATH to include
 563     // the location of the x64 CRT DLLs. This is only the case when using a
 564     // component=shared_library build (i.e. generally dev debug builds). The
 565     // x86 CRT DLLs are in e.g. out\Debug for chrome.exe etc., so the x64 ones
 566     // are put in out\Debug\x64 which we add to the PATH here so that loader
 567     // can find them. See http://crbug.com/346034.
 568     scoped_ptr<base::Environment> env(base::Environment::Create());
 569     static const char kPath[] = "PATH";
 570     std::string old_path;
 571     base::FilePath module_path;
 572     if (!PathService::Get(base::FILE_MODULE, &module_path)) {
 573       SendErrorToRenderer("could not get path to current module");
 574       return false;
 575     }
 576     std::string x64_crt_path =
 577         base::WideToUTF8(module_path.DirName().Append(L"x64").value());
 578     if (!env->GetVar(kPath, &old_path)) {
 579       env->SetVar(kPath, x64_crt_path);
 580     } else if (!IsInPath(old_path, x64_crt_path)) {
 581       std::string new_path(old_path);
 582       new_path.append(";");
 583       new_path.append(x64_crt_path);
 584       env->SetVar(kPath, new_path);
 585     }
 586 #endif  // _DLL
 587   }
 588 #endif
 589
 590   scoped_ptr<CommandLine> cmd_line(new CommandLine(exe_path));
 591   CopyNaClCommandLineArguments(cmd_line.get());
 592
 593   cmd_line->AppendSwitchASCII(switches::kProcessType,
 594                               (uses_nonsfi_mode_ ?
 595                                switches::kNaClLoaderNonSfiProcess :
 596                                switches::kNaClLoaderProcess));
 597   cmd_line->AppendSwitchASCII(switches::kProcessChannelID, channel_id);
 598   if (NaClBrowser::GetDelegate()->DialogsAreSuppressed())
 599     cmd_line->AppendSwitch(switches::kNoErrorDialogs);
 600
 601   // On Windows we might need to start the broker process to launch a new loader
 602 #if defined(OS_WIN)
 603   if (RunningOnWOW64()) {
 604     if (!NaClBrokerService::GetInstance()->LaunchLoader(
 605             weak_factory_.GetWeakPtr(), channel_id)) {
 606       SendErrorToRenderer("broker service did not launch process");
 607       return false;
 608     }
 609     return true;
 610   }
 611 #endif
 612   process_->Launch(
 613       new NaClSandboxedProcessLauncherDelegate(process_->GetHost()),
 614       cmd_line.release());
 615   return true;
 616 }
 617
 618 bool NaClProcessHost::OnMessageReceived(const IPC::Message& msg) {
 619   bool handled = true;
 620   if (uses_nonsfi_mode_) {
 621     // IPC messages relating to NaCl's validation cache must not be exposed
 622     // in Non-SFI Mode, otherwise a Non-SFI nexe could use
 623     // SetKnownToValidate to create a hole in the SFI sandbox.
 624     IPC_BEGIN_MESSAGE_MAP(NaClProcessHost, msg)
 625       IPC_MESSAGE_HANDLER(NaClProcessHostMsg_PpapiChannelsCreated,
 626                           OnPpapiChannelsCreated)
 627       IPC_MESSAGE_UNHANDLED(handled = false)
 628     IPC_END_MESSAGE_MAP()
 629   } else {
 630     IPC_BEGIN_MESSAGE_MAP(NaClProcessHost, msg)
 631       IPC_MESSAGE_HANDLER(NaClProcessMsg_QueryKnownToValidate,
 632                           OnQueryKnownToValidate)
 633       IPC_MESSAGE_HANDLER(NaClProcessMsg_SetKnownToValidate,
 634                           OnSetKnownToValidate)
 635       IPC_MESSAGE_HANDLER(NaClProcessMsg_ResolveFileToken,
 636                           OnResolveFileToken)
 637
 638 #if defined(OS_WIN)
 639       IPC_MESSAGE_HANDLER_DELAY_REPLY(
 640           NaClProcessMsg_AttachDebugExceptionHandler,
 641           OnAttachDebugExceptionHandler)
 642       IPC_MESSAGE_HANDLER(NaClProcessHostMsg_DebugStubPortSelected,
 643                           OnDebugStubPortSelected)
 644 #endif
 645       IPC_MESSAGE_HANDLER(NaClProcessHostMsg_PpapiChannelsCreated,
 646                           OnPpapiChannelsCreated)
 647       IPC_MESSAGE_UNHANDLED(handled = false)
 648     IPC_END_MESSAGE_MAP()
 649   }
 650   return handled;
 651 }
 652
 653 void NaClProcessHost::OnProcessLaunched() {
 654   if (!StartWithLaunchedProcess())
 655     delete this;
 656 }
 657
 658 // Called when the NaClBrowser singleton has been fully initialized.
 659 void NaClProcessHost::OnResourcesReady() {
 660   NaClBrowser* nacl_browser = NaClBrowser::GetInstance();
 661   if (!nacl_browser->IsReady()) {
 662     SendErrorToRenderer("could not acquire shared resources needed by NaCl");
 663     delete this;
 664   } else if (!StartNaClExecution()) {
 665     delete this;
 666   }
 667 }
 668
 669 bool NaClProcessHost::ReplyToRenderer(
 670     const IPC::ChannelHandle& ppapi_channel_handle,
 671     const IPC::ChannelHandle& trusted_channel_handle,
 672     const IPC::ChannelHandle& manifest_service_channel_handle) {
 673 #if defined(OS_WIN)
 674   // If we are on 64-bit Windows, the NaCl process's sandbox is
 675   // managed by a different process from the renderer's sandbox.  We
 676   // need to inform the renderer's sandbox about the NaCl process so
 677   // that the renderer can send handles to the NaCl process using
 678   // BrokerDuplicateHandle().
 679   if (RunningOnWOW64()) {
 680     if (!content::BrokerAddTargetPeer(process_->GetData().handle)) {
 681       SendErrorToRenderer("BrokerAddTargetPeer() failed");
 682       return false;
 683     }
 684   }
 685 #endif
 686
 687   FileDescriptor imc_handle_for_renderer;
 688 #if defined(OS_WIN)
 689   // Copy the handle into the renderer process.
 690   HANDLE handle_in_renderer;
 691   if (!DuplicateHandle(base::GetCurrentProcessHandle(),
 692                        socket_for_renderer_.TakePlatformFile(),
 693                        nacl_host_message_filter_->PeerHandle(),
 694                        &handle_in_renderer,
 695                        0,  // Unused given DUPLICATE_SAME_ACCESS.
 696                        FALSE,
 697                        DUPLICATE_CLOSE_SOURCE | DUPLICATE_SAME_ACCESS)) {
 698     SendErrorToRenderer("DuplicateHandle() failed");
 699     return false;
 700   }
 701   imc_handle_for_renderer = reinterpret_cast<FileDescriptor>(
 702       handle_in_renderer);
 703 #else
 704   // No need to dup the imc_handle - we don't pass it anywhere else so
 705   // it cannot be closed.
 706   FileDescriptor imc_handle;
 707   imc_handle.fd = socket_for_renderer_.TakePlatformFile();
 708   imc_handle.auto_close = true;
 709   imc_handle_for_renderer = imc_handle;
 710 #endif
 711
 712   const ChildProcessData& data = process_->GetData();
 713   base::SharedMemoryHandle crash_info_shmem_renderer_handle;
 714   if (!crash_info_shmem_.ShareToProcess(nacl_host_message_filter_->PeerHandle(),
 715                                         &crash_info_shmem_renderer_handle)) {
 716     SendErrorToRenderer("ShareToProcess() failed");
 717     return false;
 718   }
 719
 720   SendMessageToRenderer(
 721       NaClLaunchResult(imc_handle_for_renderer,
 722                        ppapi_channel_handle,
 723                        trusted_channel_handle,
 724                        manifest_service_channel_handle,
 725                        base::GetProcId(data.handle),
 726                        data.id,
 727                        crash_info_shmem_renderer_handle),
 728       std::string() /* error_message */);
 729
 730   // Now that the crash information shmem handles have been shared with the
 731   // plugin and the renderer, the browser can close its handle.
 732   crash_info_shmem_.Close();
 733   return true;
 734 }
 735
 736 void NaClProcessHost::SendErrorToRenderer(const std::string& error_message) {
 737   LOG(ERROR) << "NaCl process launch failed: " << error_message;
 738   SendMessageToRenderer(NaClLaunchResult(), error_message);
 739 }
 740
 741 void NaClProcessHost::SendMessageToRenderer(
 742     const NaClLaunchResult& result,
 743     const std::string& error_message) {
 744   DCHECK(nacl_host_message_filter_.get());
 745   DCHECK(reply_msg_);
 746   if (nacl_host_message_filter_.get() != NULL && reply_msg_ != NULL) {
 747     NaClHostMsg_LaunchNaCl::WriteReplyParams(
 748         reply_msg_, result, error_message);
 749     nacl_host_message_filter_->Send(reply_msg_);
 750     nacl_host_message_filter_ = NULL;
 751     reply_msg_ = NULL;
 752   }
 753 }
 754
 755 void NaClProcessHost::SetDebugStubPort(int port) {
 756   NaClBrowser* nacl_browser = NaClBrowser::GetInstance();
 757   nacl_browser->SetProcessGdbDebugStubPort(process_->GetData().id, port);
 758 }
 759
 760 #if defined(OS_POSIX)
 761 // TCP port we chose for NaCl debug stub. It can be any other number.
 762 static const uint16_t kInitialDebugStubPort = 4014;
 763
 764 net::SocketDescriptor NaClProcessHost::GetDebugStubSocketHandle() {
 765   net::SocketDescriptor s = net::kInvalidSocket;
 766   // We always try to allocate the default port first. If this fails, we then
 767   // allocate any available port.
 768   // On success, if the test system has register a handler
 769   // (GdbDebugStubPortListener), we fire a notification.
 770   uint16 port = kInitialDebugStubPort;
 771   s = net::TCPListenSocket::CreateAndBind("127.0.0.1", port);
 772   if (s == net::kInvalidSocket) {
 773     s = net::TCPListenSocket::CreateAndBindAnyPort("127.0.0.1", &port);
 774   }
 775   if (s != net::kInvalidSocket) {
 776     SetDebugStubPort(port);
 777   }
 778   if (s == net::kInvalidSocket) {
 779     LOG(ERROR) << "failed to open socket for debug stub";
 780     return net::kInvalidSocket;
 781   } else {
 782     LOG(WARNING) << "debug stub on port " << port;
 783   }
 784   if (listen(s, 1)) {
 785     LOG(ERROR) << "listen() failed on debug stub socket";
 786     if (IGNORE_EINTR(close(s)) < 0)
 787       PLOG(ERROR) << "failed to close debug stub socket";
 788     return net::kInvalidSocket;
 789   }
 790   return s;
 791 }
 792 #endif
 793
 794 #if defined(OS_WIN)
 795 void NaClProcessHost::OnDebugStubPortSelected(uint16_t debug_stub_port) {
 796   CHECK(!uses_nonsfi_mode_);
 797   SetDebugStubPort(debug_stub_port);
 798 }
 799 #endif
 800
 801 bool NaClProcessHost::StartNaClExecution() {
 802   NaClBrowser* nacl_browser = NaClBrowser::GetInstance();
 803
 804   NaClStartParams params;
 805
 806   // Enable PPAPI proxy channel creation only for renderer processes.
 807   params.enable_ipc_proxy = enable_ppapi_proxy();
 808   params.process_type = process_type_;
 809   if (uses_nonsfi_mode_) {
 810     // Currently, non-SFI mode is supported only on Linux.
 811 #if defined(OS_LINUX)
 812     // In non-SFI mode, we do not use SRPC. Make sure that the socketpair is
 813     // not created.
 814     DCHECK(!socket_for_sel_ldr_.IsValid());
 815 #endif
 816   } else {
 817     params.validation_cache_enabled = nacl_browser->ValidationCacheIsEnabled();
 818     params.validation_cache_key = nacl_browser->GetValidationCacheKey();
 819     params.version = NaClBrowser::GetDelegate()->GetVersionString();
 820     params.enable_debug_stub = enable_debug_stub_ &&
 821         NaClBrowser::GetDelegate()->URLMatchesDebugPatterns(manifest_url_);
 822
 823     const ChildProcessData& data = process_->GetData();
 824     if (!ShareHandleToSelLdr(data.handle,
 825                              socket_for_sel_ldr_.TakePlatformFile(),
 826                              true,
 827                              &params.handles)) {
 828       return false;
 829     }
 830
 831     const base::File& irt_file = nacl_browser->IrtFile();
 832     CHECK(irt_file.IsValid());
 833     // Send over the IRT file handle.  We don't close our own copy!
 834     if (!ShareHandleToSelLdr(data.handle, irt_file.GetPlatformFile(), false,
 835                              &params.handles)) {
 836       return false;
 837     }
 838
 839 #if defined(OS_MACOSX)
 840     // For dynamic loading support, NaCl requires a file descriptor that
 841     // was created in /tmp, since those created with shm_open() are not
 842     // mappable with PROT_EXEC.  Rather than requiring an extra IPC
 843     // round trip out of the sandbox, we create an FD here.
 844     base::SharedMemory memory_buffer;
 845     base::SharedMemoryCreateOptions options;
 846     options.size = 1;
 847     options.executable = true;
 848     if (!memory_buffer.Create(options)) {
 849       DLOG(ERROR) << "Failed to allocate memory buffer";
 850       return false;
 851     }
 852     FileDescriptor memory_fd;
 853     memory_fd.fd = dup(memory_buffer.handle().fd);
 854     if (memory_fd.fd < 0) {
 855       DLOG(ERROR) << "Failed to dup() a file descriptor";
 856       return false;
 857     }
 858     memory_fd.auto_close = true;
 859     params.handles.push_back(memory_fd);
 860 #endif
 861
 862 #if defined(OS_POSIX)
 863     if (params.enable_debug_stub) {
 864       net::SocketDescriptor server_bound_socket = GetDebugStubSocketHandle();
 865       if (server_bound_socket != net::kInvalidSocket) {
 866         params.debug_stub_server_bound_socket =
 867             FileDescriptor(server_bound_socket, true);
 868       }
 869     }
 870 #endif
 871   }
 872
 873   if (!crash_info_shmem_.ShareToProcess(process_->GetData().handle,
 874                                         &params.crash_info_shmem_handle)) {
 875     DLOG(ERROR) << "Failed to ShareToProcess() a shared memory buffer";
 876     return false;
 877   }
 878
 879   base::FilePath file_path;
 880   // Don't retrieve the file path when using nonsfi mode; there's no validation
 881   // caching in that case, so it's unnecessary work, and would expose the file
 882   // path to the plugin.
 883   if (!uses_nonsfi_mode_ &&
 884       NaClBrowser::GetInstance()->GetFilePath(nexe_token_.lo,
 885                                               nexe_token_.hi,
 886                                               &file_path)) {
 887     // We have to reopen the file in the browser process; we don't want a
 888     // compromised renderer to pass an arbitrary fd that could get loaded
 889     // into the plugin process.
 890     if (base::PostTaskAndReplyWithResult(
 891            content::BrowserThread::GetBlockingPool(),
 892            FROM_HERE,
 893            base::Bind(OpenNaClReadExecImpl,
 894                       file_path,
 895                       true /* is_executable */),
 896            base::Bind(&NaClProcessHost::StartNaClFileResolved,
 897                       weak_factory_.GetWeakPtr(),
 898                       params,
 899                       file_path))) {
 900       return true;
 901     }
 902   }
 903
 904   params.nexe_file = IPC::TakeFileHandleForProcess(nexe_file_.Pass(),
 905                                                    process_->GetData().handle);
 906   process_->Send(new NaClProcessMsg_Start(params));
 907   return true;
 908 }
 909
 910 void NaClProcessHost::StartNaClFileResolved(
 911     NaClStartParams params,
 912     const base::FilePath& file_path,
 913     base::File checked_nexe_file) {
 914   if (checked_nexe_file.IsValid()) {
 915     // Release the file received from the renderer. This has to be done on a
 916     // thread where IO is permitted, though.
 917     content::BrowserThread::GetBlockingPool()->PostTask(
 918         FROM_HERE,
 919         base::Bind(&CloseFile, base::Passed(nexe_file_.Pass())));
 920     params.nexe_file_path_metadata = file_path;
 921     params.nexe_file = IPC::TakeFileHandleForProcess(
 922         checked_nexe_file.Pass(), process_->GetData().handle);
 923   } else {
 924     params.nexe_file = IPC::TakeFileHandleForProcess(
 925         nexe_file_.Pass(), process_->GetData().handle);
 926   }
 927   process_->Send(new NaClProcessMsg_Start(params));
 928 }
 929
 930 // This method is called when NaClProcessHostMsg_PpapiChannelCreated is
 931 // received.
 932 void NaClProcessHost::OnPpapiChannelsCreated(
 933     const IPC::ChannelHandle& browser_channel_handle,
 934     const IPC::ChannelHandle& ppapi_renderer_channel_handle,
 935     const IPC::ChannelHandle& trusted_renderer_channel_handle,
 936     const IPC::ChannelHandle& manifest_service_channel_handle) {
 937   if (!enable_ppapi_proxy()) {
 938     ReplyToRenderer(IPC::ChannelHandle(),
 939                     trusted_renderer_channel_handle,
 940                     manifest_service_channel_handle);
 941     return;
 942   }
 943
 944   if (!ipc_proxy_channel_.get()) {
 945     DCHECK_EQ(PROCESS_TYPE_NACL_LOADER, process_->GetData().process_type);
 946
 947     ipc_proxy_channel_ =
 948         IPC::ChannelProxy::Create(browser_channel_handle,
 949                                   IPC::Channel::MODE_CLIENT,
 950                                   NULL,
 951                                   base::MessageLoopProxy::current().get());
 952     // Create the browser ppapi host and enable PPAPI message dispatching to the
 953     // browser process.
 954     ppapi_host_.reset(content::BrowserPpapiHost::CreateExternalPluginProcess(
 955         ipc_proxy_channel_.get(),  // sender
 956         permissions_,
 957         process_->GetData().handle,
 958         ipc_proxy_channel_.get(),
 959         nacl_host_message_filter_->render_process_id(),
 960         render_view_id_,
 961         profile_directory_));
 962     ppapi_host_->SetOnKeepaliveCallback(
 963         NaClBrowser::GetDelegate()->GetOnKeepaliveCallback());
 964
 965     ppapi::PpapiNaClPluginArgs args;
 966     args.off_the_record = nacl_host_message_filter_->off_the_record();
 967     args.permissions = permissions_;
 968     args.keepalive_throttle_interval_milliseconds =
 969         keepalive_throttle_interval_milliseconds_;
 970     CommandLine* cmdline = CommandLine::ForCurrentProcess();
 971     DCHECK(cmdline);
 972     std::string flag_whitelist[] = {
 973       switches::kV,
 974       switches::kVModule,
 975     };
 976     for (size_t i = 0; i < arraysize(flag_whitelist); ++i) {
 977       std::string value = cmdline->GetSwitchValueASCII(flag_whitelist[i]);
 978       if (!value.empty()) {
 979         args.switch_names.push_back(flag_whitelist[i]);
 980         args.switch_values.push_back(value);
 981       }
 982     }
 983
 984     ppapi_host_->GetPpapiHost()->AddHostFactoryFilter(
 985         scoped_ptr<ppapi::host::HostFactory>(
 986             NaClBrowser::GetDelegate()->CreatePpapiHostFactory(
 987                 ppapi_host_.get())));
 988
 989     // Send a message to initialize the IPC dispatchers in the NaCl plugin.
 990     ipc_proxy_channel_->Send(new PpapiMsg_InitializeNaClDispatcher(args));
 991
 992     // Let the renderer know that the IPC channels are established.
 993     ReplyToRenderer(ppapi_renderer_channel_handle,
 994                     trusted_renderer_channel_handle,
 995                     manifest_service_channel_handle);
 996   } else {
 997     // Attempt to open more than 1 browser channel is not supported.
 998     // Shut down the NaCl process.
 999     process_->GetHost()->ForceShutdown();
1000   }
1001 }
1002
1003 bool NaClProcessHost::StartWithLaunchedProcess() {
1004   NaClBrowser* nacl_browser = NaClBrowser::GetInstance();
1005
1006   if (nacl_browser->IsReady()) {
1007     return StartNaClExecution();
1008   } else if (nacl_browser->IsOk()) {
1009     nacl_browser->WaitForResources(
1010         base::Bind(&NaClProcessHost::OnResourcesReady,
1011                    weak_factory_.GetWeakPtr()));
1012     return true;
1013   } else {
1014     SendErrorToRenderer("previously failed to acquire shared resources");
1015     return false;
1016   }
1017 }
1018
1019 void NaClProcessHost::OnQueryKnownToValidate(const std::string& signature,
1020                                              bool* result) {
1021   CHECK(!uses_nonsfi_mode_);
1022   NaClBrowser* nacl_browser = NaClBrowser::GetInstance();
1023   *result = nacl_browser->QueryKnownToValidate(signature, off_the_record_);
1024 }
1025
1026 void NaClProcessHost::OnSetKnownToValidate(const std::string& signature) {
1027   CHECK(!uses_nonsfi_mode_);
1028   NaClBrowser::GetInstance()->SetKnownToValidate(
1029       signature, off_the_record_);
1030 }
1031
1032 void NaClProcessHost::OnResolveFileToken(uint64 file_token_lo,
1033                                          uint64 file_token_hi) {
1034   // Was the file registered?
1035   //
1036   // Note that the file path cache is of bounded size, and old entries can get
1037   // evicted.  If a large number of NaCl modules are being launched at once,
1038   // resolving the file_token may fail because the path cache was thrashed
1039   // while the file_token was in flight.  In this case the query fails, and we
1040   // need to fall back to the slower path.
1041   //
1042   // However: each NaCl process will consume 2-3 entries as it starts up, this
1043   // means that eviction will not happen unless you start up 33+ NaCl processes
1044   // at the same time, and this still requires worst-case timing.  As a
1045   // practical matter, no entries should be evicted prematurely.
1046   // The cache itself should take ~ (150 characters * 2 bytes/char + ~60 bytes
1047   // data structure overhead) * 100 = 35k when full, so making it bigger should
1048   // not be a problem, if needed.
1049   //
1050   // Each NaCl process will consume 2-3 entries because the manifest and main
1051   // nexe are currently not resolved.  Shared libraries will be resolved.  They
1052   // will be loaded sequentially, so they will only consume a single entry
1053   // while the load is in flight.
1054   //
1055   // TODO(ncbray): track behavior with UMA. If entries are getting evicted or
1056   // bogus keys are getting queried, this would be good to know.
1057   CHECK(!uses_nonsfi_mode_);
1058   base::FilePath file_path;
1059   if (!NaClBrowser::GetInstance()->GetFilePath(
1060         file_token_lo, file_token_hi, &file_path)) {
1061     Send(new NaClProcessMsg_ResolveFileTokenReply(
1062              file_token_lo,
1063              file_token_hi,
1064              IPC::PlatformFileForTransit(),
1065              base::FilePath()));
1066     return;
1067   }
1068
1069   // Open the file.
1070   if (!base::PostTaskAndReplyWithResult(
1071           content::BrowserThread::GetBlockingPool(),
1072           FROM_HERE,
1073           base::Bind(OpenNaClReadExecImpl, file_path, true /* is_executable */),
1074           base::Bind(&NaClProcessHost::FileResolved,
1075                      weak_factory_.GetWeakPtr(),
1076                      file_token_lo,
1077                      file_token_hi,
1078                      file_path))) {
1079     Send(new NaClProcessMsg_ResolveFileTokenReply(
1080             file_token_lo,
1081             file_token_hi,
1082             IPC::PlatformFileForTransit(),
1083             base::FilePath()));
1084   }
1085 }
1086
1087 void NaClProcessHost::FileResolved(
1088     uint64_t file_token_lo,
1089     uint64_t file_token_hi,
1090     const base::FilePath& file_path,
1091     base::File file) {
1092   base::FilePath out_file_path;
1093   IPC::PlatformFileForTransit out_handle;
1094   if (file.IsValid()) {
1095     out_file_path = file_path;
1096     out_handle = IPC::TakeFileHandleForProcess(
1097         file.Pass(),
1098         process_->GetData().handle);
1099   } else {
1100     out_handle = IPC::InvalidPlatformFileForTransit();
1101   }
1102   Send(new NaClProcessMsg_ResolveFileTokenReply(
1103            file_token_lo,
1104            file_token_hi,
1105            out_handle,
1106            out_file_path));
1107 }
1108
1109 #if defined(OS_WIN)
1110 void NaClProcessHost::OnAttachDebugExceptionHandler(const std::string& info,
1111                                                     IPC::Message* reply_msg) {
1112   CHECK(!uses_nonsfi_mode_);
1113   if (!AttachDebugExceptionHandler(info, reply_msg)) {
1114     // Send failure message.
1115     NaClProcessMsg_AttachDebugExceptionHandler::WriteReplyParams(reply_msg,
1116                                                                  false);
1117     Send(reply_msg);
1118   }
1119 }
1120
1121 bool NaClProcessHost::AttachDebugExceptionHandler(const std::string& info,
1122                                                   IPC::Message* reply_msg) {
1123   bool enable_exception_handling = process_type_ == kNativeNaClProcessType;
1124   if (!enable_exception_handling && !enable_debug_stub_) {
1125     DLOG(ERROR) <<
1126         "Debug exception handler requested by NaCl process when not enabled";
1127     return false;
1128   }
1129   if (debug_exception_handler_requested_) {
1130     // The NaCl process should not request this multiple times.
1131     DLOG(ERROR) << "Multiple AttachDebugExceptionHandler requests received";
1132     return false;
1133   }
1134   debug_exception_handler_requested_ = true;
1135
1136   base::ProcessId nacl_pid = base::GetProcId(process_->GetData().handle);
1137   base::ProcessHandle temp_handle;
1138   // We cannot use process_->GetData().handle because it does not have
1139   // the necessary access rights.  We open the new handle here rather
1140   // than in the NaCl broker process in case the NaCl loader process
1141   // dies before the NaCl broker process receives the message we send.
1142   // The debug exception handler uses DebugActiveProcess() to attach,
1143   // but this takes a PID.  We need to prevent the NaCl loader's PID
1144   // from being reused before DebugActiveProcess() is called, and
1145   // holding a process handle open achieves this.
1146   if (!base::OpenProcessHandleWithAccess(
1147            nacl_pid,
1148            base::kProcessAccessQueryInformation |
1149            base::kProcessAccessSuspendResume |
1150            base::kProcessAccessTerminate |
1151            base::kProcessAccessVMOperation |
1152            base::kProcessAccessVMRead |
1153            base::kProcessAccessVMWrite |
1154            base::kProcessAccessDuplicateHandle |
1155            base::kProcessAccessWaitForTermination,
1156            &temp_handle)) {
1157     LOG(ERROR) << "Failed to get process handle";
1158     return false;
1159   }
1160   base::win::ScopedHandle process_handle(temp_handle);
1161
1162   attach_debug_exception_handler_reply_msg_.reset(reply_msg);
1163   // If the NaCl loader is 64-bit, the process running its debug
1164   // exception handler must be 64-bit too, so we use the 64-bit NaCl
1165   // broker process for this.  Otherwise, on a 32-bit system, we use
1166   // the 32-bit browser process to run the debug exception handler.
1167   if (RunningOnWOW64()) {
1168     return NaClBrokerService::GetInstance()->LaunchDebugExceptionHandler(
1169                weak_factory_.GetWeakPtr(), nacl_pid, process_handle.Get(),
1170                info);
1171   } else {
1172     NaClStartDebugExceptionHandlerThread(
1173         process_handle.Take(), info,
1174         base::MessageLoopProxy::current(),
1175         base::Bind(&NaClProcessHost::OnDebugExceptionHandlerLaunchedByBroker,
1176                    weak_factory_.GetWeakPtr()));
1177     return true;
1178   }
1179 }
1180 #endif
1181
1182 }  // namespace nacl