content/zygote/zygote_linux.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 "content/zygote/zygote_linux.h"
   6
   7 #include <fcntl.h>
   8 #include <string.h>
   9 #include <sys/socket.h>
  10 #include <sys/types.h>
  11 #include <sys/wait.h>
  12
  13 #include "base/command_line.h"
  14 #include "base/files/file_util.h"
  15 #include "base/linux_util.h"
  16 #include "base/logging.h"
  17 #include "base/macros.h"
  18 #include "base/memory/scoped_vector.h"
  19 #include "base/pickle.h"
  20 #include "base/posix/eintr_wrapper.h"
  21 #include "base/posix/global_descriptors.h"
  22 #include "base/posix/unix_domain_socket_linux.h"
  23 #include "base/process/kill.h"
  24 #include "base/process/launch.h"
  25 #include "base/process/process.h"
  26 #include "base/process/process_handle.h"
  27 #include "base/trace_event/trace_event.h"
  28 #include "content/common/child_process_sandbox_support_impl_linux.h"
  29 #include "content/common/sandbox_linux/sandbox_linux.h"
  30 #include "content/common/set_process_title.h"
  31 #include "content/common/zygote_commands_linux.h"
  32 #include "content/public/common/content_descriptors.h"
  33 #include "content/public/common/result_codes.h"
  34 #include "content/public/common/sandbox_linux.h"
  35 #include "content/public/common/send_zygote_child_ping_linux.h"
  36 #include "content/public/common/zygote_fork_delegate_linux.h"
  37 #include "ipc/ipc_channel.h"
  38 #include "ipc/ipc_switches.h"
  39 #include "sandbox/linux/services/credentials.h"
  40 #include "sandbox/linux/services/namespace_sandbox.h"
  41
  42 // See http://code.google.com/p/chromium/wiki/LinuxZygote
  43
  44 namespace content {
  45
  46 namespace {
  47
  48 // NOP function. See below where this handler is installed.
  49 void SIGCHLDHandler(int signal) {
  50 }
  51
  52 int LookUpFd(const base::GlobalDescriptors::Mapping& fd_mapping, uint32_t key) {
  53   for (size_t index = 0; index < fd_mapping.size(); ++index) {
  54     if (fd_mapping[index].key == key)
  55       return fd_mapping[index].fd;
  56   }
  57   return -1;
  58 }
  59
  60 void CreatePipe(base::ScopedFD* read_pipe, base::ScopedFD* write_pipe) {
  61   int raw_pipe[2];
  62   PCHECK(0 == pipe(raw_pipe));
  63   read_pipe->reset(raw_pipe[0]);
  64   write_pipe->reset(raw_pipe[1]);
  65 }
  66
  67 void KillAndReap(pid_t pid, ZygoteForkDelegate* helper) {
  68   if (helper) {
  69     // Helper children may be forked in another PID namespace, so |pid| might
  70     // be meaningless to us; or we just might not be able to directly send it
  71     // signals.  So we can't kill it.
  72     // Additionally, we're not its parent, so we can't reap it anyway.
  73     // TODO(mdempsky): Extend the ZygoteForkDelegate API to handle this.
  74     LOG(WARNING) << "Unable to kill or reap helper children";
  75     return;
  76   }
  77
  78   // Kill the child process in case it's not already dead, so we can safely
  79   // perform a blocking wait.
  80   PCHECK(0 == kill(pid, SIGKILL));
  81   PCHECK(pid == HANDLE_EINTR(waitpid(pid, NULL, 0)));
  82 }
  83
  84 }  // namespace
  85
  86 Zygote::Zygote(int sandbox_flags, ScopedVector<ZygoteForkDelegate> helpers,
  87                const std::vector<base::ProcessHandle>& extra_children,
  88                const std::vector<int>& extra_fds)
  89     : sandbox_flags_(sandbox_flags),
  90       helpers_(helpers.Pass()),
  91       initial_uma_index_(0),
  92       extra_children_(extra_children),
  93       extra_fds_(extra_fds) {}
  94
  95 Zygote::~Zygote() {
  96 }
  97
  98 bool Zygote::ProcessRequests() {
  99   // A SOCK_SEQPACKET socket is installed in fd 3. We get commands from the
 100   // browser on it.
 101   // A SOCK_DGRAM is installed in fd 5. This is the sandbox IPC channel.
 102   // See http://code.google.com/p/chromium/wiki/LinuxSandboxIPC
 103
 104   // We need to accept SIGCHLD, even though our handler is a no-op because
 105   // otherwise we cannot wait on children. (According to POSIX 2001.)
 106   struct sigaction action;
 107   memset(&action, 0, sizeof(action));
 108   action.sa_handler = &SIGCHLDHandler;
 109   PCHECK(sigaction(SIGCHLD, &action, NULL) == 0);
 110
 111   if (UsingSUIDSandbox() || UsingNSSandbox()) {
 112     // Let the ZygoteHost know we are ready to go.
 113     // The receiving code is in content/browser/zygote_host_linux.cc.
 114     bool r = base::UnixDomainSocket::SendMsg(kZygoteSocketPairFd,
 115                                              kZygoteHelloMessage,
 116                                              sizeof(kZygoteHelloMessage),
 117                                              std::vector<int>());
 118 #if defined(OS_CHROMEOS)
 119     LOG_IF(WARNING, !r) << "Sending zygote magic failed";
 120     // Exit normally on chromeos because session manager may send SIGTERM
 121     // right after the process starts and it may fail to send zygote magic
 122     // number to browser process.
 123     if (!r)
 124       _exit(RESULT_CODE_NORMAL_EXIT);
 125 #else
 126     CHECK(r) << "Sending zygote magic failed";
 127 #endif
 128   }
 129
 130   for (;;) {
 131     // This function call can return multiple times, once per fork().
 132     if (HandleRequestFromBrowser(kZygoteSocketPairFd))
 133       return true;
 134   }
 135 }
 136
 137 bool Zygote::GetProcessInfo(base::ProcessHandle pid,
 138                             ZygoteProcessInfo* process_info) {
 139   DCHECK(process_info);
 140   const ZygoteProcessMap::const_iterator it = process_info_map_.find(pid);
 141   if (it == process_info_map_.end()) {
 142     return false;
 143   }
 144   *process_info = it->second;
 145   return true;
 146 }
 147
 148 bool Zygote::UsingSUIDSandbox() const {
 149   return sandbox_flags_ & kSandboxLinuxSUID;
 150 }
 151
 152 bool Zygote::UsingNSSandbox() const {
 153   return sandbox_flags_ & kSandboxLinuxUserNS;
 154 }
 155
 156 bool Zygote::HandleRequestFromBrowser(int fd) {
 157   ScopedVector<base::ScopedFD> fds;
 158   char buf[kZygoteMaxMessageLength];
 159   const ssize_t len = base::UnixDomainSocket::RecvMsg(
 160       fd, buf, sizeof(buf), &fds);
 161
 162   if (len == 0 || (len == -1 && errno == ECONNRESET)) {
 163     // EOF from the browser. We should die.
 164     // TODO(earthdok): call __sanititizer_cov_dump() here to obtain code
 165     // coverage  for the Zygote. Currently it's not possible because of
 166     // confusion over who is responsible for closing the file descriptor.
 167     for (std::vector<int>::iterator it = extra_fds_.begin();
 168          it < extra_fds_.end(); ++it) {
 169       PCHECK(0 == IGNORE_EINTR(close(*it)));
 170     }
 171 #if !defined(SANITIZER_COVERAGE)
 172     // TODO(earthdok): add watchdog thread before using this in builds not
 173     // using sanitizer coverage.
 174     CHECK(extra_children_.empty());
 175 #endif
 176     for (std::vector<base::ProcessHandle>::iterator it =
 177              extra_children_.begin();
 178          it < extra_children_.end(); ++it) {
 179       PCHECK(*it == HANDLE_EINTR(waitpid(*it, NULL, 0)));
 180     }
 181     _exit(0);
 182     return false;
 183   }
 184
 185   if (len == -1) {
 186     PLOG(ERROR) << "Error reading message from browser";
 187     return false;
 188   }
 189
 190   base::Pickle pickle(buf, len);
 191   base::PickleIterator iter(pickle);
 192
 193   int kind;
 194   if (iter.ReadInt(&kind)) {
 195     switch (kind) {
 196       case kZygoteCommandFork:
 197         // This function call can return multiple times, once per fork().
 198         return HandleForkRequest(fd, iter, fds.Pass());
 199
 200       case kZygoteCommandReap:
 201         if (!fds.empty())
 202           break;
 203         HandleReapRequest(fd, iter);
 204         return false;
 205       case kZygoteCommandGetTerminationStatus:
 206         if (!fds.empty())
 207           break;
 208         HandleGetTerminationStatus(fd, iter);
 209         return false;
 210       case kZygoteCommandGetSandboxStatus:
 211         HandleGetSandboxStatus(fd, iter);
 212         return false;
 213       case kZygoteCommandForkRealPID:
 214         // This shouldn't happen in practice, but some failure paths in
 215         // HandleForkRequest (e.g., if ReadArgsAndFork fails during depickling)
 216         // could leave this command pending on the socket.
 217         LOG(ERROR) << "Unexpected real PID message from browser";
 218         NOTREACHED();
 219         return false;
 220       default:
 221         NOTREACHED();
 222         break;
 223     }
 224   }
 225
 226   LOG(WARNING) << "Error parsing message from browser";
 227   return false;
 228 }
 229
 230 // TODO(jln): remove callers to this broken API. See crbug.com/274855.
 231 void Zygote::HandleReapRequest(int fd, base::PickleIterator iter) {
 232   base::ProcessId child;
 233
 234   if (!iter.ReadInt(&child)) {
 235     LOG(WARNING) << "Error parsing reap request from browser";
 236     return;
 237   }
 238
 239   ZygoteProcessInfo child_info;
 240   if (!GetProcessInfo(child, &child_info)) {
 241     LOG(ERROR) << "Child not found!";
 242     NOTREACHED();
 243     return;
 244   }
 245
 246   if (!child_info.started_from_helper) {
 247     // Do not call base::EnsureProcessTerminated() under ThreadSanitizer, as it
 248     // spawns a separate thread which may live until the call to fork() in the
 249     // zygote. As a result, ThreadSanitizer will report an error and almost
 250     // disable race detection in the child process.
 251     // Not calling EnsureProcessTerminated() may result in zombie processes
 252     // sticking around. This will only happen during testing, so we can live
 253     // with this for now.
 254 #if !defined(THREAD_SANITIZER)
 255     // TODO(jln): this old code is completely broken. See crbug.com/274855.
 256     base::EnsureProcessTerminated(base::Process(child_info.internal_pid));
 257 #else
 258     LOG(WARNING) << "Zygote process omitting a call to "
 259         << "base::EnsureProcessTerminated() for child pid " << child
 260         << " under ThreadSanitizer. See http://crbug.com/274855.";
 261 #endif
 262   } else {
 263     // For processes from the helper, send a GetTerminationStatus request
 264     // with known_dead set to true.
 265     // This is not perfect, as the process may be killed instantly, but is
 266     // better than ignoring the request.
 267     base::TerminationStatus status;
 268     int exit_code;
 269     bool got_termination_status =
 270         GetTerminationStatus(child, true /* known_dead */, &status, &exit_code);
 271     DCHECK(got_termination_status);
 272   }
 273   process_info_map_.erase(child);
 274 }
 275
 276 bool Zygote::GetTerminationStatus(base::ProcessHandle real_pid,
 277                                   bool known_dead,
 278                                   base::TerminationStatus* status,
 279                                   int* exit_code) {
 280
 281   ZygoteProcessInfo child_info;
 282   if (!GetProcessInfo(real_pid, &child_info)) {
 283     LOG(ERROR) << "Zygote::GetTerminationStatus for unknown PID "
 284                << real_pid;
 285     NOTREACHED();
 286     return false;
 287   }
 288   // We know about |real_pid|.
 289   const base::ProcessHandle child = child_info.internal_pid;
 290   if (child_info.started_from_helper) {
 291     if (!child_info.started_from_helper->GetTerminationStatus(
 292             child, known_dead, status, exit_code)) {
 293       return false;
 294     }
 295   } else {
 296     // Handle the request directly.
 297     if (known_dead) {
 298       *status = base::GetKnownDeadTerminationStatus(child, exit_code);
 299     } else {
 300       // We don't know if the process is dying, so get its status but don't
 301       // wait.
 302       *status = base::GetTerminationStatus(child, exit_code);
 303     }
 304   }
 305   // Successfully got a status for |real_pid|.
 306   if (*status != base::TERMINATION_STATUS_STILL_RUNNING) {
 307     // Time to forget about this process.
 308     process_info_map_.erase(real_pid);
 309   }
 310
 311   if (WIFEXITED(*exit_code)) {
 312     const int exit_status = WEXITSTATUS(*exit_code);
 313     if (exit_status == sandbox::NamespaceSandbox::SignalExitCode(SIGINT) ||
 314         exit_status == sandbox::NamespaceSandbox::SignalExitCode(SIGTERM)) {
 315       *status = base::TERMINATION_STATUS_PROCESS_WAS_KILLED;
 316     }
 317   }
 318
 319   return true;
 320 }
 321
 322 void Zygote::HandleGetTerminationStatus(int fd, base::PickleIterator iter) {
 323   bool known_dead;
 324   base::ProcessHandle child_requested;
 325
 326   if (!iter.ReadBool(&known_dead) || !iter.ReadInt(&child_requested)) {
 327     LOG(WARNING) << "Error parsing GetTerminationStatus request "
 328                  << "from browser";
 329     return;
 330   }
 331
 332   base::TerminationStatus status;
 333   int exit_code;
 334
 335   bool got_termination_status =
 336       GetTerminationStatus(child_requested, known_dead, &status, &exit_code);
 337   if (!got_termination_status) {
 338     // Assume that if we can't find the child in the sandbox, then
 339     // it terminated normally.
 340     NOTREACHED();
 341     status = base::TERMINATION_STATUS_NORMAL_TERMINATION;
 342     exit_code = RESULT_CODE_NORMAL_EXIT;
 343   }
 344
 345   base::Pickle write_pickle;
 346   write_pickle.WriteInt(static_cast<int>(status));
 347   write_pickle.WriteInt(exit_code);
 348   ssize_t written =
 349       HANDLE_EINTR(write(fd, write_pickle.data(), write_pickle.size()));
 350   if (written != static_cast<ssize_t>(write_pickle.size()))
 351     PLOG(ERROR) << "write";
 352 }
 353
 354 int Zygote::ForkWithRealPid(const std::string& process_type,
 355                             const base::GlobalDescriptors::Mapping& fd_mapping,
 356                             const std::string& channel_id,
 357                             base::ScopedFD pid_oracle,
 358                             std::string* uma_name,
 359                             int* uma_sample,
 360                             int* uma_boundary_value) {
 361   ZygoteForkDelegate* helper = NULL;
 362   for (ScopedVector<ZygoteForkDelegate>::iterator i = helpers_.begin();
 363        i != helpers_.end();
 364        ++i) {
 365     if ((*i)->CanHelp(process_type, uma_name, uma_sample, uma_boundary_value)) {
 366       helper = *i;
 367       break;
 368     }
 369   }
 370
 371   base::ScopedFD read_pipe, write_pipe;
 372   base::ProcessId pid = 0;
 373   if (helper) {
 374     int ipc_channel_fd = LookUpFd(fd_mapping, kPrimaryIPCChannel);
 375     if (ipc_channel_fd < 0) {
 376       DLOG(ERROR) << "Failed to find kPrimaryIPCChannel in FD mapping";
 377       return -1;
 378     }
 379     std::vector<int> fds;
 380     fds.push_back(ipc_channel_fd);  // kBrowserFDIndex
 381     fds.push_back(pid_oracle.get());  // kPIDOracleFDIndex
 382     pid = helper->Fork(process_type, fds, channel_id);
 383
 384     // Helpers should never return in the child process.
 385     CHECK_NE(pid, 0);
 386   } else {
 387     CreatePipe(&read_pipe, &write_pipe);
 388     if (sandbox_flags_ & kSandboxLinuxPIDNS &&
 389         sandbox_flags_ & kSandboxLinuxUserNS) {
 390       pid = sandbox::NamespaceSandbox::ForkInNewPidNamespace(
 391           /*drop_capabilities_in_child=*/true);
 392     } else {
 393       pid = sandbox::Credentials::ForkAndDropCapabilitiesInChild();
 394     }
 395   }
 396
 397   if (pid == 0) {
 398     // If the process is the init process inside a PID namespace, it must have
 399     // explicit signal handlers.
 400     if (getpid() == 1) {
 401       static const int kTerminationSignals[] = {
 402           SIGINT, SIGTERM, SIGHUP, SIGQUIT, SIGABRT, SIGPIPE, SIGUSR1, SIGUSR2};
 403       for (const int sig : kTerminationSignals) {
 404         sandbox::NamespaceSandbox::InstallTerminationSignalHandler(
 405             sig, sandbox::NamespaceSandbox::SignalExitCode(sig));
 406       }
 407     }
 408
 409     // In the child process.
 410     write_pipe.reset();
 411
 412     // Ping the PID oracle socket so the browser can find our PID.
 413     CHECK(SendZygoteChildPing(pid_oracle.get()));
 414
 415     // Now read back our real PID from the zygote.
 416     base::ProcessId real_pid;
 417     if (!base::ReadFromFD(read_pipe.get(),
 418                           reinterpret_cast<char*>(&real_pid),
 419                           sizeof(real_pid))) {
 420       LOG(FATAL) << "Failed to synchronise with parent zygote process";
 421     }
 422     if (real_pid <= 0) {
 423       LOG(FATAL) << "Invalid pid from parent zygote";
 424     }
 425 #if defined(OS_LINUX)
 426     // Sandboxed processes need to send the global, non-namespaced PID when
 427     // setting up an IPC channel to their parent.
 428     IPC::Channel::SetGlobalPid(real_pid);
 429     // Force the real PID so chrome event data have a PID that corresponds
 430     // to system trace event data.
 431     base::trace_event::TraceLog::GetInstance()->SetProcessID(
 432         static_cast<int>(real_pid));
 433 #endif
 434     return 0;
 435   }
 436
 437   // In the parent process.
 438   read_pipe.reset();
 439   pid_oracle.reset();
 440
 441   // Always receive a real PID from the zygote host, though it might
 442   // be invalid (see below).
 443   base::ProcessId real_pid;
 444   {
 445     ScopedVector<base::ScopedFD> recv_fds;
 446     char buf[kZygoteMaxMessageLength];
 447     const ssize_t len = base::UnixDomainSocket::RecvMsg(
 448         kZygoteSocketPairFd, buf, sizeof(buf), &recv_fds);
 449     CHECK_GT(len, 0);
 450     CHECK(recv_fds.empty());
 451
 452     base::Pickle pickle(buf, len);
 453     base::PickleIterator iter(pickle);
 454
 455     int kind;
 456     CHECK(iter.ReadInt(&kind));
 457     CHECK(kind == kZygoteCommandForkRealPID);
 458     CHECK(iter.ReadInt(&real_pid));
 459   }
 460
 461   // Fork failed.
 462   if (pid < 0) {
 463     return -1;
 464   }
 465
 466   // If we successfully forked a child, but it crashed without sending
 467   // a message to the browser, the browser won't have found its PID.
 468   if (real_pid < 0) {
 469     KillAndReap(pid, helper);
 470     return -1;
 471   }
 472
 473   // If we're not using a helper, send the PID back to the child process.
 474   if (!helper) {
 475     ssize_t written =
 476         HANDLE_EINTR(write(write_pipe.get(), &real_pid, sizeof(real_pid)));
 477     if (written != sizeof(real_pid)) {
 478       KillAndReap(pid, helper);
 479       return -1;
 480     }
 481   }
 482
 483   // Now set-up this process to be tracked by the Zygote.
 484   if (process_info_map_.find(real_pid) != process_info_map_.end()) {
 485     LOG(ERROR) << "Already tracking PID " << real_pid;
 486     NOTREACHED();
 487   }
 488   process_info_map_[real_pid].internal_pid = pid;
 489   process_info_map_[real_pid].started_from_helper = helper;
 490
 491   return real_pid;
 492 }
 493
 494 base::ProcessId Zygote::ReadArgsAndFork(base::PickleIterator iter,
 495                                         ScopedVector<base::ScopedFD> fds,
 496                                         std::string* uma_name,
 497                                         int* uma_sample,
 498                                         int* uma_boundary_value) {
 499   std::vector<std::string> args;
 500   int argc = 0;
 501   int numfds = 0;
 502   base::GlobalDescriptors::Mapping mapping;
 503   std::string process_type;
 504   std::string channel_id;
 505   const std::string channel_id_prefix = std::string("--")
 506       + switches::kProcessChannelID + std::string("=");
 507
 508   if (!iter.ReadString(&process_type))
 509     return -1;
 510   if (!iter.ReadInt(&argc))
 511     return -1;
 512
 513   for (int i = 0; i < argc; ++i) {
 514     std::string arg;
 515     if (!iter.ReadString(&arg))
 516       return -1;
 517     args.push_back(arg);
 518     if (arg.compare(0, channel_id_prefix.length(), channel_id_prefix) == 0)
 519       channel_id = arg.substr(channel_id_prefix.length());
 520   }
 521
 522   if (!iter.ReadInt(&numfds))
 523     return -1;
 524   if (numfds != static_cast<int>(fds.size()))
 525     return -1;
 526
 527   // First FD is the PID oracle socket.
 528   if (fds.size() < 1)
 529     return -1;
 530   base::ScopedFD pid_oracle(fds[0]->Pass());
 531
 532   // Remaining FDs are for the global descriptor mapping.
 533   for (int i = 1; i < numfds; ++i) {
 534     base::GlobalDescriptors::Key key;
 535     if (!iter.ReadUInt32(&key))
 536       return -1;
 537     mapping.push_back(base::GlobalDescriptors::Descriptor(key, fds[i]->get()));
 538   }
 539
 540   mapping.push_back(base::GlobalDescriptors::Descriptor(
 541       static_cast<uint32_t>(kSandboxIPCChannel), GetSandboxFD()));
 542
 543   // Returns twice, once per process.
 544   base::ProcessId child_pid = ForkWithRealPid(process_type,
 545                                               mapping,
 546                                               channel_id,
 547                                               pid_oracle.Pass(),
 548                                               uma_name,
 549                                               uma_sample,
 550                                               uma_boundary_value);
 551   if (!child_pid) {
 552     // This is the child process.
 553
 554     // Our socket from the browser.
 555     PCHECK(0 == IGNORE_EINTR(close(kZygoteSocketPairFd)));
 556
 557     // Pass ownership of file descriptors from fds to GlobalDescriptors.
 558     for (ScopedVector<base::ScopedFD>::iterator i = fds.begin(); i != fds.end();
 559          ++i)
 560       ignore_result((*i)->release());
 561     base::GlobalDescriptors::GetInstance()->Reset(mapping);
 562
 563     // Reset the process-wide command line to our new command line.
 564     base::CommandLine::Reset();
 565     base::CommandLine::Init(0, NULL);
 566     base::CommandLine::ForCurrentProcess()->InitFromArgv(args);
 567
 568     // Update the process title. The argv was already cached by the call to
 569     // SetProcessTitleFromCommandLine in ChromeMain, so we can pass NULL here
 570     // (we don't have the original argv at this point).
 571     SetProcessTitleFromCommandLine(NULL);
 572   } else if (child_pid < 0) {
 573     LOG(ERROR) << "Zygote could not fork: process_type " << process_type
 574         << " numfds " << numfds << " child_pid " << child_pid;
 575   }
 576   return child_pid;
 577 }
 578
 579 bool Zygote::HandleForkRequest(int fd,
 580                                base::PickleIterator iter,
 581                                ScopedVector<base::ScopedFD> fds) {
 582   std::string uma_name;
 583   int uma_sample;
 584   int uma_boundary_value;
 585   base::ProcessId child_pid = ReadArgsAndFork(
 586       iter, fds.Pass(), &uma_name, &uma_sample, &uma_boundary_value);
 587   if (child_pid == 0)
 588     return true;
 589   // If there's no UMA report for this particular fork, then check if any
 590   // helpers have an initial UMA report for us to send instead.
 591   while (uma_name.empty() && initial_uma_index_ < helpers_.size()) {
 592     helpers_[initial_uma_index_++]->InitialUMA(
 593         &uma_name, &uma_sample, &uma_boundary_value);
 594   }
 595   // Must always send reply, as ZygoteHost blocks while waiting for it.
 596   base::Pickle reply_pickle;
 597   reply_pickle.WriteInt(child_pid);
 598   reply_pickle.WriteString(uma_name);
 599   if (!uma_name.empty()) {
 600     reply_pickle.WriteInt(uma_sample);
 601     reply_pickle.WriteInt(uma_boundary_value);
 602   }
 603   if (HANDLE_EINTR(write(fd, reply_pickle.data(), reply_pickle.size())) !=
 604       static_cast<ssize_t> (reply_pickle.size()))
 605     PLOG(ERROR) << "write";
 606   return false;
 607 }
 608
 609 bool Zygote::HandleGetSandboxStatus(int fd, base::PickleIterator iter) {
 610   if (HANDLE_EINTR(write(fd, &sandbox_flags_, sizeof(sandbox_flags_))) !=
 611                    sizeof(sandbox_flags_)) {
 612     PLOG(ERROR) << "write";
 613   }
 614
 615   return false;
 616 }
 617
 618 }  // namespace content