DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Header

Mercurial (5b81998bb7ab)

VCS Links

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977
/* -*- Mode: C++; tab-width: 50; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set sw=2 ts=50 et cin tw=80 : */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "mozilla/MemoryInfoDumper.h"

#include "mozilla/ClearOnShutdown.h"
#include "mozilla/FileUtils.h"
#include "mozilla/Preferences.h"
#include "mozilla/StaticPtr.h"
#include "mozilla/unused.h"
#include "mozilla/dom/ContentParent.h"
#include "mozilla/dom/ContentChild.h"
#include "nsIConsoleService.h"
#include "nsICycleCollectorListener.h"
#include "nsDirectoryServiceDefs.h"
#include "nsGZFileWriter.h"
#include "nsJSEnvironment.h"
#include "nsPrintfCString.h"

#ifdef XP_WIN
#include <process.h>
#define getpid _getpid
#else
#include <unistd.h>
#endif

#ifdef XP_LINUX
#include <errno.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#endif

#ifdef ANDROID
#include "android/log.h"
#endif

#ifdef LOG
#undef LOG
#endif

#ifdef ANDROID
#define LOG(...) __android_log_print(ANDROID_LOG_INFO, "Gecko:MemoryInfoDumper", ## __VA_ARGS__)
#else
#define LOG(...)
#endif

using namespace mozilla;
using namespace mozilla::dom;

namespace mozilla {
namespace {

class DumpMemoryReportsRunnable : public nsRunnable
{
public:
  DumpMemoryReportsRunnable(const nsAString& aIdentifier,
                            bool aMinimizeMemoryUsage,
                            bool aDumpChildProcesses)

      : mIdentifier(aIdentifier)
      , mMinimizeMemoryUsage(aMinimizeMemoryUsage)
      , mDumpChildProcesses(aDumpChildProcesses)
  {}

  NS_IMETHOD Run()
  {
    MemoryInfoDumper::DumpMemoryReportsToFile(
      mIdentifier, mMinimizeMemoryUsage, mDumpChildProcesses);
    return NS_OK;
  }

private:
  const nsString mIdentifier;
  const bool mMinimizeMemoryUsage;
  const bool mDumpChildProcesses;
};

class GCAndCCLogDumpRunnable : public nsRunnable
{
public:
  GCAndCCLogDumpRunnable(const nsAString& aIdentifier,
                         bool aDumpAllTraces,
                         bool aDumpChildProcesses)
    : mIdentifier(aIdentifier)
    , mDumpAllTraces(aDumpAllTraces)
    , mDumpChildProcesses(aDumpChildProcesses)
  {}

  NS_IMETHOD Run()
  {
    MemoryInfoDumper::DumpGCAndCCLogsToFile(
      mIdentifier, mDumpAllTraces, mDumpChildProcesses);
    return NS_OK;
  }

private:
  const nsString mIdentifier;
  const bool mDumpAllTraces;
  const bool mDumpChildProcesses;
};

} // anonymous namespace

#ifdef XP_LINUX // {
namespace {

/*
 * The following code supports dumping about:memory upon receiving a signal.
 *
 * We listen for the following signals:
 *
 *  - SIGRTMIN:     Dump our memory reporters (and those of our child
 *                  processes),
 *  - SIGRTMIN + 1: Dump our memory reporters (and those of our child
 *                  processes) after minimizing memory usage, and
 *  - SIGRTMIN + 2: Dump the GC and CC logs in this and our child processes.
 *
 * When we receive one of these signals, we write the signal number to a pipe.
 * The IO thread then notices that the pipe has been written to, and kicks off
 * the appropriate task on the main thread.
 *
 * This scheme is similar to using signalfd(), except it's portable and it
 * doesn't require the use of sigprocmask, which is problematic because it
 * masks signals received by child processes.
 *
 * In theory, we could use Chromium's MessageLoopForIO::CatchSignal() for this.
 * But that uses libevent, which does not handle the realtime signals (bug
 * 794074).
 */

// It turns out that at least on some systems, SIGRTMIN is not a compile-time
// constant, so these have to be set at runtime.
static int sDumpAboutMemorySignum;         // SIGRTMIN
static int sDumpAboutMemoryAfterMMUSignum; // SIGRTMIN + 1
static int sGCAndCCDumpSignum;             // SIGRTMIN + 2

// This is the write-end of a pipe that we use to notice when a
// dump-about-memory signal occurs.
static int sDumpAboutMemoryPipeWriteFd = -1;

void
DumpAboutMemorySignalHandler(int aSignum)
{
  // This is a signal handler, so everything in here needs to be
  // async-signal-safe.  Be careful!

  if (sDumpAboutMemoryPipeWriteFd != -1) {
    uint8_t signum = static_cast<int>(aSignum);
    write(sDumpAboutMemoryPipeWriteFd, &signum, sizeof(signum));
  }
}

/**
 * Abstract base class for something which watches an fd and takes action when
 * we can read from it without blocking.
 */
class FdWatcher : public MessageLoopForIO::Watcher
                , public nsIObserver
{
protected:
  MessageLoopForIO::FileDescriptorWatcher mReadWatcher;
  int mFd;

public:
  FdWatcher()
    : mFd(-1)
  {
    MOZ_ASSERT(NS_IsMainThread());
  }

  virtual ~FdWatcher()
  {
    // StopWatching should have run.
    MOZ_ASSERT(mFd == -1);
  }

  /**
   * Open the fd to watch.  If we encounter an error, return -1.
   */
  virtual int OpenFd() = 0;

  /**
   * Called when you can read() from the fd without blocking.  Note that this
   * function is also called when you're at eof (read() returns 0 in this case).
   */
  virtual void OnFileCanReadWithoutBlocking(int aFd) = 0;
  virtual void OnFileCanWriteWithoutBlocking(int Afd) {};

  NS_DECL_ISUPPORTS

  /**
   * Initialize this object.  This should be called right after the object is
   * constructed.  (This would go in the constructor, except we interact with
   * XPCOM, which we can't do from a constructor because our refcount is 0 at
   * that point.)
   */
  void Init()
  {
    MOZ_ASSERT(NS_IsMainThread());

    nsCOMPtr<nsIObserverService> os = services::GetObserverService();
    os->AddObserver(this, "xpcom-shutdown", /* ownsWeak = */ false);

    XRE_GetIOMessageLoop()->PostTask(
        FROM_HERE,
        NewRunnableMethod(this, &FdWatcher::StartWatching));
  }

  // Implementations may call this function multiple times if they ensure that
  // it's safe to call OpenFd() multiple times and they call StopWatching()
  // first.
  virtual void StartWatching()
  {
    MOZ_ASSERT(XRE_GetIOMessageLoop() == MessageLoopForIO::current());
    MOZ_ASSERT(mFd == -1);

    mFd = OpenFd();
    if (mFd == -1) {
      LOG("FdWatcher: OpenFd failed.");
      return;
    }

    MessageLoopForIO::current()->WatchFileDescriptor(
      mFd, /* persistent = */ true,
      MessageLoopForIO::WATCH_READ,
      &mReadWatcher, this);
  }

  // Since implementations can call StartWatching() multiple times, they can of
  // course call StopWatching() multiple times.
  virtual void StopWatching()
  {
    MOZ_ASSERT(XRE_GetIOMessageLoop() == MessageLoopForIO::current());

    mReadWatcher.StopWatchingFileDescriptor();
    if (mFd != -1) {
      close(mFd);
      mFd = -1;
    }
  }

  NS_IMETHOD Observe(nsISupports* aSubject, const char* aTopic,
                     const PRUnichar* aData)
  {
    MOZ_ASSERT(NS_IsMainThread());
    MOZ_ASSERT(!strcmp(aTopic, "xpcom-shutdown"));

    XRE_GetIOMessageLoop()->PostTask(
        FROM_HERE,
        NewRunnableMethod(this, &FdWatcher::StopWatching));

    return NS_OK;
  }
};

NS_IMPL_THREADSAFE_ISUPPORTS1(FdWatcher, nsIObserver);

class SignalPipeWatcher : public FdWatcher
{
public:
  static void Create()
  {
    nsRefPtr<SignalPipeWatcher> sw = new SignalPipeWatcher();
    sw->Init();
  }

  virtual ~SignalPipeWatcher()
  {
    MOZ_ASSERT(sDumpAboutMemoryPipeWriteFd == -1);
  }

  virtual int OpenFd()
  {
    MOZ_ASSERT(XRE_GetIOMessageLoop() == MessageLoopForIO::current());

    sDumpAboutMemorySignum = SIGRTMIN;
    sDumpAboutMemoryAfterMMUSignum = SIGRTMIN + 1;
    sGCAndCCDumpSignum = SIGRTMIN + 2;

    // Create a pipe.  When we receive a signal in our signal handler, we'll
    // write the signum to the write-end of this pipe.
    int pipeFds[2];
    if (pipe(pipeFds)) {
      LOG("SignalPipeWatcher failed to create pipe.");
      return -1;
    }

    // Close this pipe on calls to exec().
    fcntl(pipeFds[0], F_SETFD, FD_CLOEXEC);
    fcntl(pipeFds[1], F_SETFD, FD_CLOEXEC);

    int readFd = pipeFds[0];
    sDumpAboutMemoryPipeWriteFd = pipeFds[1];

    struct sigaction action;
    memset(&action, 0, sizeof(action));
    sigemptyset(&action.sa_mask);
    action.sa_handler = DumpAboutMemorySignalHandler;

    if (sigaction(sDumpAboutMemorySignum, &action, nullptr)) {
      LOG("SignalPipeWatcher failed to register about:memory "
          "dump signal handler.");
    }
    if (sigaction(sDumpAboutMemoryAfterMMUSignum, &action, nullptr)) {
      LOG("SignalPipeWatcher failed to register about:memory "
          "dump after MMU signal handler.");
    }
    if (sigaction(sGCAndCCDumpSignum, &action, nullptr)) {
      LOG("Failed to register GC+CC dump signal handler.");
    }

    return readFd;
  }

  virtual void StopWatching()
  {
    MOZ_ASSERT(XRE_GetIOMessageLoop() == MessageLoopForIO::current());

    // Close sDumpAboutMemoryPipeWriteFd /after/ setting the fd to -1.
    // Otherwise we have the (admittedly far-fetched) race where we
    //
    //  1) close sDumpAboutMemoryPipeWriteFd
    //  2) open a new fd with the same number as sDumpAboutMemoryPipeWriteFd
    //     had.
    //  3) receive a signal, then write to the fd.
    int pipeWriteFd = sDumpAboutMemoryPipeWriteFd;
    PR_ATOMIC_SET(&sDumpAboutMemoryPipeWriteFd, -1);
    close(pipeWriteFd);

    FdWatcher::StopWatching();
  }

  virtual void OnFileCanReadWithoutBlocking(int aFd)
  {
    MOZ_ASSERT(XRE_GetIOMessageLoop() == MessageLoopForIO::current());

    uint8_t signum;
    ssize_t numReceived = read(aFd, &signum, sizeof(signum));
    if (numReceived != sizeof(signum)) {
      LOG("Error reading from buffer in "
          "SignalPipeWatcher::OnFileCanReadWithoutBlocking.");
      return;
    }

    if (signum == sDumpAboutMemorySignum ||
        signum == sDumpAboutMemoryAfterMMUSignum) {
      // Dump our memory reports (but run this on the main thread!).
      bool doMMUFirst = signum == sDumpAboutMemoryAfterMMUSignum;
      nsRefPtr<DumpMemoryReportsRunnable> runnable =
        new DumpMemoryReportsRunnable(
            /* identifier = */ EmptyString(),
            doMMUFirst,
            /* dumpChildProcesses = */ true);
      NS_DispatchToMainThread(runnable);
    }
    else if (signum == sGCAndCCDumpSignum) {
      // Dump GC and CC logs (from the main thread).
      nsRefPtr<GCAndCCLogDumpRunnable> runnable =
        new GCAndCCLogDumpRunnable(
            /* identifier = */ EmptyString(),
            /* allTraces = */ true,
            /* dumpChildProcesses = */ true);
      NS_DispatchToMainThread(runnable);
    }
    else {
      LOG("SignalPipeWatcher got unexpected signum.");
    }
  }
};

class FifoWatcher : public FdWatcher
{
public:
  static void MaybeCreate()
  {
    MOZ_ASSERT(NS_IsMainThread());

    if (XRE_GetProcessType() != GeckoProcessType_Default) {
      // We want this to be main-process only, since two processes can't listen
      // to the same fifo.
      return;
    }

    if (!Preferences::GetBool("memory_info_dumper.watch_fifo.enabled", false)) {
      LOG("Fifo watcher disabled via pref.");
      return;
    }

    // The FifoWatcher is held alive by the observer service.
    nsRefPtr<FifoWatcher> fw = new FifoWatcher();
    fw->Init();
  }

  virtual int OpenFd()
  {
    // If the memory_info_dumper.directory pref is specified, put the fifo
    // there.  Otherwise, put it into the system's tmp directory.

    nsCOMPtr<nsIFile> file;
    nsAutoCString dirPath;
    nsresult rv = Preferences::GetCString(
      "memory_info_dumper.watch_fifo.directory", &dirPath);

    if (NS_SUCCEEDED(rv)) {
      rv = XRE_GetFileFromPath(dirPath.get(), getter_AddRefs(file));
      if (NS_FAILED(rv)) {
        LOG("FifoWatcher failed to open file \"%s\"", dirPath.get());
        return -1;
      }
    } else {
      rv = NS_GetSpecialDirectory(NS_OS_TEMP_DIR, getter_AddRefs(file));
      NS_ENSURE_SUCCESS(rv, -1);
    }

    rv = file->AppendNative(NS_LITERAL_CSTRING("debug_info_trigger"));
    NS_ENSURE_SUCCESS(rv, -1);

    nsAutoCString path;
    rv = file->GetNativePath(path);
    NS_ENSURE_SUCCESS(rv, -1);

    // unlink might fail because the file doesn't exist, or for other reasons.
    // But we don't care it fails; any problems will be detected later, when we
    // try to mkfifo or open the file.
    if (unlink(path.get())) {
      LOG("FifoWatcher::OpenFifo unlink failed; errno=%d.  "
          "Continuing despite error.", errno);
    }

    if (mkfifo(path.get(), 0766)) {
      LOG("FifoWatcher::OpenFifo mkfifo failed; errno=%d", errno);
      return -1;
    }

#ifdef ANDROID
    // Android runs with a umask, so we need to chmod our fifo to make it
    // world-writable.
    chmod(path.get(), 0666);
#endif

    int fd;
    do {
      // The fifo will block until someone else has written to it.  In
      // particular, open() will block until someone else has opened it for
      // writing!  We want open() to succeed and read() to block, so we open
      // with NONBLOCK and then fcntl that away.
      fd = open(path.get(), O_RDONLY | O_NONBLOCK);
    } while (fd == -1 && errno == EINTR);

    if (fd == -1) {
      LOG("FifoWatcher::OpenFifo open failed; errno=%d", errno);
      return -1;
    }

    // Make fd blocking now that we've opened it.
    if (fcntl(fd, F_SETFL, 0)) {
      close(fd);
      return -1;
    }

    return fd;
  }

  virtual void OnFileCanReadWithoutBlocking(int aFd)
  {
    MOZ_ASSERT(XRE_GetIOMessageLoop() == MessageLoopForIO::current());

    char buf[1024];
    int nread;
    do {
      // sizeof(buf) - 1 to leave space for the null-terminator.
      nread = read(aFd, buf, sizeof(buf));
    } while(nread == -1 && errno == EINTR);

    if (nread == -1) {
      // We want to avoid getting into a situation where
      // OnFileCanReadWithoutBlocking is called in an infinite loop, so when
      // something goes wrong, stop watching the fifo altogether.
      LOG("FifoWatcher hit an error (%d) and is quitting.", errno);
      StopWatching();
      return;
    }

    if (nread == 0) {
      // If we get EOF, that means that the other side closed the fifo.  We need
      // to close and re-open the fifo; if we don't,
      // OnFileCanWriteWithoutBlocking will be called in an infinite loop.

      LOG("FifoWatcher closing and re-opening fifo.");
      StopWatching();
      StartWatching();
      return;
    }

    nsAutoCString inputStr;
    inputStr.Append(buf, nread);

    // Trimming whitespace is important because if you do
    //   |echo "foo" >> debug_info_trigger|,
    // it'll actually write "foo\n" to the fifo.
    inputStr.Trim("\b\t\r\n");

    bool doMemoryReport = inputStr == NS_LITERAL_CSTRING("memory report");
    bool doMMUMemoryReport = inputStr == NS_LITERAL_CSTRING("minimize memory report");
    bool doAllTracesGCCCDump = inputStr == NS_LITERAL_CSTRING("gc log");
    bool doSmallGCCCDump = inputStr == NS_LITERAL_CSTRING("abbreviated gc log");

    if (doMemoryReport || doMMUMemoryReport) {
      LOG("FifoWatcher dispatching memory report runnable.");
      nsRefPtr<DumpMemoryReportsRunnable> runnable =
        new DumpMemoryReportsRunnable(
          /* identifier = */ EmptyString(),
          doMMUMemoryReport,
          /* dumpChildProcesses = */ true);
      NS_DispatchToMainThread(runnable);
    } else if (doAllTracesGCCCDump || doSmallGCCCDump) {
      LOG("FifoWatcher dispatching GC/CC log runnable.");
      nsRefPtr<GCAndCCLogDumpRunnable> runnable =
        new GCAndCCLogDumpRunnable(
            /* identifier = */ EmptyString(),
            doAllTracesGCCCDump,
            /* dumpChildProcesses = */ true);
      NS_DispatchToMainThread(runnable);
    } else {
      LOG("Got unexpected value from fifo; ignoring it.");
    }
  }
};

} // anonymous namespace
#endif // } XP_LINUX

/* static */ void
MemoryInfoDumper::Initialize()
{
#ifdef XP_LINUX
  SignalPipeWatcher::Create();
  FifoWatcher::MaybeCreate();
#endif
}

static void
EnsureNonEmptyIdentifier(nsAString& aIdentifier)
{
  if (!aIdentifier.IsEmpty()) {
    return;
  }

  // If the identifier is empty, set it to the number of whole seconds since the
  // epoch.  This identifier will appear in the files that this process
  // generates and also the files generated by this process's children, allowing
  // us to identify which files are from the same memory report request.
  aIdentifier.AppendInt(static_cast<int64_t>(PR_Now()) / 1000000);
}

/* static */ void
MemoryInfoDumper::DumpMemoryReportsToFile(
    const nsAString& aIdentifier,
    bool aMinimizeMemoryUsage,
    bool aDumpChildProcesses)
{
  nsString identifier(aIdentifier);
  EnsureNonEmptyIdentifier(identifier);

  // Kick off memory report dumps in our child processes, if applicable.  We
  // do this before doing our own report because writing a report may be I/O
  // bound, in which case we want to busy the CPU with other reports while we
  // work on our own.
  if (aDumpChildProcesses) {
    nsTArray<ContentParent*> children;
    ContentParent::GetAll(children);
    for (uint32_t i = 0; i < children.Length(); i++) {
      unused << children[i]->SendDumpMemoryReportsToFile(
          identifier, aMinimizeMemoryUsage, aDumpChildProcesses);
    }
  }

  if (aMinimizeMemoryUsage) {
    // Minimize memory usage, then run DumpMemoryReportsToFile again.
    nsRefPtr<DumpMemoryReportsRunnable> callback =
      new DumpMemoryReportsRunnable(identifier,
          /* minimizeMemoryUsage = */ false,
          /* dumpChildProcesses = */ false);
    nsCOMPtr<nsIMemoryReporterManager> mgr =
      do_GetService("@mozilla.org/memory-reporter-manager;1");
    NS_ENSURE_TRUE(mgr,);
    nsCOMPtr<nsICancelableRunnable> runnable;
    mgr->MinimizeMemoryUsage(callback, getter_AddRefs(runnable));
    return;
  }

  DumpMemoryReportsToFileImpl(identifier);
}

/* static */ void
MemoryInfoDumper::DumpGCAndCCLogsToFile(
  const nsAString& aIdentifier,
  bool aDumpAllTraces,
  bool aDumpChildProcesses)
{
  nsString identifier(aIdentifier);
  EnsureNonEmptyIdentifier(identifier);

  if (aDumpChildProcesses) {
    nsTArray<ContentParent*> children;
    ContentParent::GetAll(children);
    for (uint32_t i = 0; i < children.Length(); i++) {
      unused << children[i]->SendDumpGCAndCCLogsToFile(
          identifier, aDumpAllTraces, aDumpChildProcesses);
    }
  }

  nsCOMPtr<nsICycleCollectorListener> logger =
    do_CreateInstance("@mozilla.org/cycle-collector-logger;1");
  logger->SetFilenameIdentifier(identifier);

  if (aDumpAllTraces) {
    nsCOMPtr<nsICycleCollectorListener> allTracesLogger;
    logger->AllTraces(getter_AddRefs(allTracesLogger));
    logger = allTracesLogger;
  }

  nsJSContext::CycleCollectNow(logger);
}

#define DUMP(o, s) \
  do { \
    nsresult rv = (o)->Write(s); \
    NS_ENSURE_SUCCESS(rv, rv); \
  } while (0)

static nsresult
DumpReport(nsIGZFileWriter *aWriter, bool aIsFirst,
  const nsACString &aProcess, const nsACString &aPath, int32_t aKind,
  int32_t aUnits, int64_t aAmount, const nsACString &aDescription)
{
  DUMP(aWriter, aIsFirst ? "[" : ",");

  // We only want to dump reports for this process.  If |aProcess| is
  // non-NULL that means we've received it from another process in response
  // to a "child-memory-reporter-request" event;  ignore such reports.
  if (!aProcess.IsEmpty()) {
    return NS_OK;
  }

  // Generate the process identifier, which is of the form "$PROCESS_NAME
  // (pid $PID)", or just "(pid $PID)" if we don't have a process name.  If
  // we're the main process, we let $PROCESS_NAME be "Main Process".
  nsAutoCString processId;
  if (XRE_GetProcessType() == GeckoProcessType_Default) {
    // We're the main process.
    processId.AssignLiteral("Main Process ");
  } else if (ContentChild *cc = ContentChild::GetSingleton()) {
    // Try to get the process name from ContentChild.
    nsAutoString processName;
    cc->GetProcessName(processName);
    processId.Assign(NS_ConvertUTF16toUTF8(processName));
    if (!processId.IsEmpty()) {
      processId.AppendLiteral(" ");
    }
  }

  // Add the PID to the identifier.
  unsigned pid = getpid();
  processId.Append(nsPrintfCString("(pid %u)", pid));

  DUMP(aWriter, "\n    {\"process\": \"");
  DUMP(aWriter, processId);

  DUMP(aWriter, "\", \"path\": \"");
  nsCString path(aPath);
  path.ReplaceSubstring("\\", "\\\\");    /* <backslash> --> \\ */
  path.ReplaceSubstring("\"", "\\\"");    // " --> \"
  DUMP(aWriter, path);

  DUMP(aWriter, "\", \"kind\": ");
  DUMP(aWriter, nsPrintfCString("%d", aKind));

  DUMP(aWriter, ", \"units\": ");
  DUMP(aWriter, nsPrintfCString("%d", aUnits));

  DUMP(aWriter, ", \"amount\": ");
  DUMP(aWriter, nsPrintfCString("%lld", aAmount));

  nsCString description(aDescription);
  description.ReplaceSubstring("\\", "\\\\");    /* <backslash> --> \\ */
  description.ReplaceSubstring("\"", "\\\"");    // " --> \"
  description.ReplaceSubstring("\n", "\\n");     // <newline> --> \n
  DUMP(aWriter, ", \"description\": \"");
  DUMP(aWriter, description);
  DUMP(aWriter, "\"}");

  return NS_OK;
}

class DumpMultiReporterCallback MOZ_FINAL : public nsIMemoryMultiReporterCallback
{
  public:
    NS_DECL_ISUPPORTS

      NS_IMETHOD Callback(const nsACString &aProcess, const nsACString &aPath,
          int32_t aKind, int32_t aUnits, int64_t aAmount,
          const nsACString &aDescription,
          nsISupports *aData)
      {
        nsCOMPtr<nsIGZFileWriter> writer = do_QueryInterface(aData);
        NS_ENSURE_TRUE(writer, NS_ERROR_FAILURE);

        // The |isFirst = false| assumes that at least one single reporter is
        // present and so will have been processed in
        // DumpMemoryReportsToFileImpl() below.
        return DumpReport(writer, /* isFirst = */ false, aProcess, aPath,
            aKind, aUnits, aAmount, aDescription);
        return NS_OK;
      }
};

NS_IMPL_ISUPPORTS1(
    DumpMultiReporterCallback
    , nsIMemoryMultiReporterCallback
    )

static void
MakeFilename(const char *aPrefix, const nsAString &aIdentifier,
             const char *aSuffix, nsACString &aResult)
{
  aResult = nsPrintfCString("%s-%s-%d.%s",
                            aPrefix,
                            NS_ConvertUTF16toUTF8(aIdentifier).get(),
                            getpid(), aSuffix);
}

static nsresult
OpenTempFile(const nsACString &aFilename, nsIFile* *aFile)
{
  nsresult rv = NS_GetSpecialDirectory(NS_OS_TEMP_DIR, aFile);
  NS_ENSURE_SUCCESS(rv, rv);

#ifdef ANDROID
  // /data/local/tmp is a true tmp directory; anyone can create a file there,
  // but only the user which created the file can remove it.  We want non-root
  // users to be able to remove these files, so we write them into a
  // subdirectory of the temp directory and chmod 777 that directory.
  rv = (*aFile)->AppendNative(NS_LITERAL_CSTRING("memory-reports"));
  NS_ENSURE_SUCCESS(rv, rv);

  // It's OK if this fails; that probably just means that the directory already
  // exists.
  (*aFile)->Create(nsIFile::DIRECTORY_TYPE, 0777);

  nsAutoCString dirPath;
  rv = (*aFile)->GetNativePath(dirPath);
  NS_ENSURE_SUCCESS(rv, rv);

  while (chmod(dirPath.get(), 0777) == -1 && errno == EINTR) {}
#endif

  nsCOMPtr<nsIFile> file(*aFile);

  rv = file->AppendNative(aFilename);
  NS_ENSURE_SUCCESS(rv, rv);

  rv = file->CreateUnique(nsIFile::NORMAL_FILE_TYPE, 0666);
  NS_ENSURE_SUCCESS(rv, rv);

#ifdef ANDROID
    // Make this file world-read/writable; the permissions passed to the
    // CreateUnique call above are not sufficient on Android, which runs with a
    // umask.
    nsAutoCString path;
    rv = file->GetNativePath(path);
    NS_ENSURE_SUCCESS(rv, rv);

    while (chmod(path.get(), 0666) == -1 && errno == EINTR) {}
#endif

  return NS_OK;
}

#ifdef MOZ_DMD
struct DMDWriteState
{
  static const size_t kBufSize = 4096;
  char mBuf[kBufSize];
  nsRefPtr<nsGZFileWriter> mGZWriter;

  DMDWriteState(nsGZFileWriter *aGZWriter)
    : mGZWriter(aGZWriter)
  {}
};

static void DMDWrite(void* aState, const char* aFmt, va_list ap)
{
  DMDWriteState *state = (DMDWriteState*)aState;
  vsnprintf(state->mBuf, state->kBufSize, aFmt, ap);
  unused << state->mGZWriter->Write(state->mBuf);
}
#endif

/* static */ nsresult
MemoryInfoDumper::DumpMemoryReportsToFileImpl(
  const nsAString& aIdentifier)
{
  MOZ_ASSERT(!aIdentifier.IsEmpty());

  // Open a new file named something like
  //
  //   incomplete-memory-report-<identifier>-<pid>.json.gz
  //
  // in NS_OS_TEMP_DIR for writing.  When we're finished writing the report,
  // we'll rename this file and get rid of the "incomplete-" prefix.
  //
  // We do this because we don't want scripts which poll the filesystem
  // looking for memory report dumps to grab a file before we're finished
  // writing to it.

  // Note that |mrFilename| is missing the "incomplete-" prefix; we'll tack
  // that on in a moment.
  nsCString mrFilename;
  MakeFilename("memory-report", aIdentifier, "json.gz", mrFilename);

  nsCOMPtr<nsIFile> mrTmpFile;
  nsresult rv;
  rv = OpenTempFile(NS_LITERAL_CSTRING("incomplete-") + mrFilename,
                    getter_AddRefs(mrTmpFile));
  NS_ENSURE_SUCCESS(rv, rv);

  nsRefPtr<nsGZFileWriter> writer = new nsGZFileWriter();
  rv = writer->Init(mrTmpFile);
  NS_ENSURE_SUCCESS(rv, rv);

  // Dump the memory reports to the file.

  // Increment this number if the format changes.
  DUMP(writer, "{\n  \"version\": 1,\n");

  DUMP(writer, "  \"hasMozMallocUsableSize\": ");

  nsCOMPtr<nsIMemoryReporterManager> mgr =
    do_GetService("@mozilla.org/memory-reporter-manager;1");
  NS_ENSURE_STATE(mgr);

  DUMP(writer, mgr->GetHasMozMallocUsableSize() ? "true" : "false");
  DUMP(writer, ",\n");
  DUMP(writer, "  \"reports\": ");

  // Process single reporters.
  bool isFirst = true;
  bool more;
  nsCOMPtr<nsISimpleEnumerator> e;
  mgr->EnumerateReporters(getter_AddRefs(e));
  while (NS_SUCCEEDED(e->HasMoreElements(&more)) && more) {
    nsCOMPtr<nsIMemoryReporter> r;
    e->GetNext(getter_AddRefs(r));

    nsCString process;
    rv = r->GetProcess(process);
    NS_ENSURE_SUCCESS(rv, rv);

    nsCString path;
    rv = r->GetPath(path);
    NS_ENSURE_SUCCESS(rv, rv);

    int32_t kind;
    rv = r->GetKind(&kind);
    NS_ENSURE_SUCCESS(rv, rv);

    int32_t units;
    rv = r->GetUnits(&units);
    NS_ENSURE_SUCCESS(rv, rv);

    int64_t amount;
    rv = r->GetAmount(&amount);
    NS_ENSURE_SUCCESS(rv, rv);

    nsCString description;
    rv = r->GetDescription(description);
    NS_ENSURE_SUCCESS(rv, rv);

    rv = DumpReport(writer, isFirst, process, path, kind, units, amount,
                    description);
    NS_ENSURE_SUCCESS(rv, rv);

    isFirst = false;
  }

  // Process multi-reporters.
  nsCOMPtr<nsISimpleEnumerator> e2;
  mgr->EnumerateMultiReporters(getter_AddRefs(e2));
  nsRefPtr<DumpMultiReporterCallback> cb = new DumpMultiReporterCallback();
  while (NS_SUCCEEDED(e2->HasMoreElements(&more)) && more) {
    nsCOMPtr<nsIMemoryMultiReporter> r;
    e2->GetNext(getter_AddRefs(r));
    r->CollectReports(cb, writer);
  }

  DUMP(writer, "\n  ]\n}");

  rv = writer->Finish();
  NS_ENSURE_SUCCESS(rv, rv);

#ifdef MOZ_DMD
  // Open a new file named something like
  //
  //   dmd-<identifier>-<pid>.txt.gz
  //
  // in NS_OS_TEMP_DIR for writing, and dump DMD output to it.  This must occur
  // after the memory reporters have been run (above), but before the
  // memory-reports file has been renamed (so scripts can detect the DMD file,
  // if present).

  nsCString dmdFilename;
  MakeFilename("dmd", aIdentifier, "txt.gz", dmdFilename);

  nsCOMPtr<nsIFile> dmdFile;
  rv = OpenTempFile(dmdFilename, getter_AddRefs(dmdFile));
  NS_ENSURE_SUCCESS(rv, rv);

  nsRefPtr<nsGZFileWriter> dmdWriter = new nsGZFileWriter();
  rv = dmdWriter->Init(dmdFile);
  NS_ENSURE_SUCCESS(rv, rv);

  // Dump DMD output to the file.

  DMDWriteState state(dmdWriter);
  dmd::Writer w(DMDWrite, &state);
  mozilla::dmd::Dump(w);

  rv = dmdWriter->Finish();
  NS_ENSURE_SUCCESS(rv, rv);
#endif  // MOZ_DMD

  // Rename the file, now that we're done dumping the report.  The file's
  // ultimate destination is "memory-report<-identifier>-<pid>.json.gz".

  nsCOMPtr<nsIFile> mrFinalFile;
  rv = NS_GetSpecialDirectory(NS_OS_TEMP_DIR, getter_AddRefs(mrFinalFile));
  NS_ENSURE_SUCCESS(rv, rv);

#ifdef ANDROID
  rv = mrFinalFile->AppendNative(NS_LITERAL_CSTRING("memory-reports"));
  NS_ENSURE_SUCCESS(rv, rv);
#endif

  rv = mrFinalFile->AppendNative(mrFilename);
  NS_ENSURE_SUCCESS(rv, rv);

  rv = mrFinalFile->CreateUnique(nsIFile::NORMAL_FILE_TYPE, 0600);
  NS_ENSURE_SUCCESS(rv, rv);

  nsAutoString mrActualFinalFilename;
  rv = mrFinalFile->GetLeafName(mrActualFinalFilename);
  NS_ENSURE_SUCCESS(rv, rv);

  rv = mrTmpFile->MoveTo(/* directory */ nullptr, mrActualFinalFilename);
  NS_ENSURE_SUCCESS(rv, rv);

  nsCOMPtr<nsIConsoleService> cs =
    do_GetService(NS_CONSOLESERVICE_CONTRACTID, &rv);
  NS_ENSURE_SUCCESS(rv, rv);

  nsString path;
  mrTmpFile->GetPath(path);
  NS_ENSURE_SUCCESS(rv, rv);

  nsString msg = NS_LITERAL_STRING(
    "nsIMemoryReporterManager::dumpReports() dumped reports to ");
  msg.Append(path);
  return cs->LogStringMessage(msg.get());
}

#undef DUMP
} // namespace mozilla