text: // Copyright (c) 2012 The Chromium Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  
  // This is a simple application that stress-tests the crash recovery of the disk
  // cache. The main application starts a copy of itself on a loop, checking the
  // exit code of the child process. When the child dies in an unexpected way,
  // the main application quits.
  
  // The child application has two threads: one to exercise the cache in an
  // infinite loop, and another one to asynchronously kill the process.
  
  // A regular build should never crash.
  // To test that the disk cache doesn't generate critical errors with regular
  // application level crashes, edit stress_support.h.
  
  #include <string>
  #include <vector>
  
  #include "base/at_exit.h"
  #include "base/bind.h"
  #include "base/command_line.h"
  #include "base/debug/debugger.h"
  #include "base/files/file_path.h"
  #include "base/logging.h"
  #include "base/message_loop/message_loop.h"
  #include "base/path_service.h"
  #include "base/process/kill.h"
  #include "base/process/launch.h"
  #include "base/strings/string_number_conversions.h"
  #include "base/strings/string_util.h"
  #include "base/strings/utf_string_conversions.h"
  #include "base/threading/platform_thread.h"
  #include "base/threading/thread.h"
  #include "net/base/io_buffer.h"
  #include "net/base/net_errors.h"
  #include "net/base/test_completion_callback.h"
  #include "net/disk_cache/blockfile/backend_impl.h"
  #include "net/disk_cache/blockfile/stress_support.h"
  #include "net/disk_cache/blockfile/trace.h"
  #include "net/disk_cache/disk_cache.h"
  #include "net/disk_cache/disk_cache_test_util.h"
  
  #if defined(OS_WIN)
  #include "base/logging_win.h"
  #endif
  
  using base::Time;
  
  const int kError = -1;
  const int kExpectedCrash = 100;
  
  // Starts a new process.
  int RunSlave(int iteration) {
    base::FilePath exe;
    PathService::Get(base::FILE_EXE, &exe);
  
    base::CommandLine cmdline(exe);
    cmdline.AppendArg(base::IntToString(iteration));
  
    base::Process process = base::LaunchProcess(cmdline, base::LaunchOptions());
    if (!process.IsValid()) {
      printf("Unable to run test\n");
      return kError;
    }
  
    int exit_code;
    if (!process.WaitForExit(&exit_code)) {
      printf("Unable to get return code\n");
      return kError;
    }
    return exit_code;
  }
  
  // Main loop for the master process.
  int MasterCode() {
    for (int i = 0; i < 100000; i++) {
      int ret = RunSlave(i);
      if (kExpectedCrash != ret)
        return ret;
    }
  
    printf("More than enough...\n");
  
    return 0;
  }
  
  // -----------------------------------------------------------------------
  
  std::string GenerateStressKey() {
    char key[20 * 1024];
    size_t size = 50 + rand() % 20000;
    CacheTestFillBuffer(key, size, true);
  
    key[size - 1] = '\0';
    return std::string(key);
  }
  
  // This thread will loop forever, adding and removing entries from the cache.
  // iteration is the current crash cycle, so the entries on the cache are marked
  // to know which instance of the application wrote them.
  void StressTheCache(int iteration) {
    int cache_size = 0x2000000;  // 32MB.
    uint32 mask = 0xfff;  // 4096 entries.
  
    base::FilePath path;
    PathService::Get(base::DIR_TEMP, &path);
    path = path.AppendASCII("cache_test_stress");
  
    base::Thread cache_thread("CacheThread");
    if (!cache_thread.StartWithOptions(
            base::Thread::Options(base::MessageLoop::TYPE_IO, 0)))
      return;
  
    disk_cache::BackendImpl* cache =
        new disk_cache::BackendImpl(path, mask,
                                    cache_thread.message_loop_proxy().get(),
                                    NULL);
    cache->SetMaxSize(cache_size);
    cache->SetFlags(disk_cache::kNoLoadProtection);
  
    net::TestCompletionCallback cb;
    int rv = cache->Init(cb.callback());
  
    if (cb.GetResult(rv) != net::OK) {
      printf("Unable to initialize cache.\n");
      return;
    }
    printf("Iteration %d, initial entries: %d\n", iteration,
           cache->GetEntryCount());
  
    int seed = static_cast<int>(Time::Now().ToInternalValue());
    srand(seed);
  
    // kNumKeys is meant to be enough to have about 3x or 4x iterations before
    // the process crashes.
  #ifdef NDEBUG
    const int kNumKeys = 4000;
  #else
    const int kNumKeys = 1200;
  #endif
    const int kNumEntries = 30;
    std::string keys[kNumKeys];
    disk_cache::Entry* entries[kNumEntries] = {0};
  
    for (int i = 0; i < kNumKeys; i++) {
      keys[i] = GenerateStressKey();
    }
  
    const int kSize = 20000;
    scoped_refptr<net::IOBuffer> buffer(new net::IOBuffer(kSize));
    memset(buffer->data(), 'k', kSize);
  
    for (int i = 0;; i++) {
      int slot = rand() % kNumEntries;
      int key = rand() % kNumKeys;
      bool truncate = (rand() % 2 == 0);
      int size = kSize - (rand() % 20) * kSize / 20;
  
      if (entries[slot])
        entries[slot]->Close();
  
      net::TestCompletionCallback cb;
      rv = cache->OpenEntry(keys[key], &entries[slot], cb.callback());
      if (cb.GetResult(rv) != net::OK) {
        rv = cache->CreateEntry(keys[key], &entries[slot], cb.callback());
        CHECK_EQ(net::OK, cb.GetResult(rv));
      }
  
      base::snprintf(buffer->data(), kSize,
                     "i: %d iter: %d, size: %d, truncate: %d     ", i, iteration,
                     size, truncate ? 1 : 0);
      rv = entries[slot]->WriteData(0, 0, buffer.get(), size, cb.callback(),
                                    truncate);
      CHECK_EQ(size, cb.GetResult(rv));
  
      if (rand() % 100 > 80) {
        key = rand() % kNumKeys;
        net::TestCompletionCallback cb2;
        rv = cache->DoomEntry(keys[key], cb2.callback());
        cb2.GetResult(rv);
      }
  
      if (!(i % 100))
        printf("Entries: %d    \r", i);
    }
  }
  
  // We want to prevent the timer thread from killing the process while we are
  // waiting for the debugger to attach.
  bool g_crashing = false;
  
  // RunSoon() and CrashCallback() reference each other, unfortunately.
  void RunSoon(base::MessageLoop* target_loop);
  
  void CrashCallback() {
    // Keep trying to run.
    RunSoon(base::MessageLoop::current());
  
    if (g_crashing)
      return;
  
    if (rand() % 100 > 30) {
      printf("sweet death...\n");
  #if defined(OS_WIN)
      // Windows does more work on _exit() that we would like, so we use Kill.
      base::KillProcessById(base::GetCurrentProcId(), kExpectedCrash, false);
  #elif defined(OS_POSIX)
      // On POSIX, _exit() will terminate the process with minimal cleanup,
      // and it is cleaner than killing.
      _exit(kExpectedCrash);
  #endif
    }
  }
  
  void RunSoon(base::MessageLoop* target_loop) {
    const base::TimeDelta kTaskDelay = base::TimeDelta::FromSeconds(10);
    target_loop->PostDelayedTask(
        FROM_HERE, base::Bind(&CrashCallback), kTaskDelay);
  }
  
  // We leak everything here :)
  bool StartCrashThread() {
    base::Thread* thread = new base::Thread("party_crasher");
    if (!thread->Start())
      return false;
  
    RunSoon(thread->message_loop());
    return true;
  }
  
  void CrashHandler(const std::string& str) {
    g_crashing = true;
    base::debug::BreakDebugger();
  }
  
  bool MessageHandler(int severity, const char* file, int line,
                      size_t message_start, const std::string& str) {
    const size_t kMaxMessageLen = 48;
    char message[kMaxMessageLen];
    size_t len = std::min(str.length() - message_start, kMaxMessageLen - 1);
  
    memcpy(message, str.c_str() + message_start, len);
    message[len] = '\0';
  #if !defined(DISK_CACHE_TRACE_TO_LOG)
    disk_cache::Trace("%s", message);
  #endif
    return false;
  }
  
  // -----------------------------------------------------------------------
  
  #if defined(OS_WIN)
  // {B9A153D4-31C3-48e4-9ABF-D54383F14A0D}
  const GUID kStressCacheTraceProviderName = {
      0xb9a153d4, 0x31c3, 0x48e4,
          { 0x9a, 0xbf, 0xd5, 0x43, 0x83, 0xf1, 0x4a, 0xd } };
  #endif
  
  int main(int argc, const char* argv[]) {
    // Setup an AtExitManager so Singleton objects will be destructed.
    base::AtExitManager at_exit_manager;
  
    if (argc < 2)
      return MasterCode();
  
    logging::SetLogAssertHandler(CrashHandler);
    logging::SetLogMessageHandler(MessageHandler);
  
  #if defined(OS_WIN)
    logging::LogEventProvider::Initialize(kStressCacheTraceProviderName);
  #else
    base::CommandLine::Init(argc, argv);
    logging::LoggingSettings settings;
    settings.logging_dest = logging::LOG_TO_SYSTEM_DEBUG_LOG;
    logging::InitLogging(settings);
  #endif
  
    // Some time for the memory manager to flush stuff.
    base::PlatformThread::Sleep(base::TimeDelta::FromSeconds(3));
    base::MessageLoopForIO message_loop;
  
    char* end;
    long int iteration = strtol(argv[1], &end, 0);
  
    if (!StartCrashThread()) {
      printf("failed to start thread\n");
      return kError;
    }
  
    StressTheCache(iteration);
    return 0;
  }
  