| // 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. |
| |
| #include "chrome/browser/nacl_host/nacl_browser.h" |
| |
| #include "base/command_line.h" |
| #include "base/file_util.h" |
| #include "base/message_loop/message_loop.h" |
| #include "base/metrics/histogram.h" |
| #include "base/path_service.h" |
| #include "base/pickle.h" |
| #include "base/rand_util.h" |
| #include "base/time/time.h" |
| #include "base/win/windows_version.h" |
| #include "build/build_config.h" |
| #include "content/public/browser/browser_thread.h" |
| #include "url/gurl.h" |
| |
| namespace { |
| |
| // An arbitrary delay to coalesce multiple writes to the cache. |
| const int kValidationCacheCoalescingTimeMS = 6000; |
| const char kValidationCacheSequenceName[] = "NaClValidationCache"; |
| const base::FilePath::CharType kValidationCacheFileName[] = |
| FILE_PATH_LITERAL("nacl_validation_cache.bin"); |
| |
| const bool kValidationCacheEnabledByDefault = true; |
| |
| enum ValidationCacheStatus { |
| CACHE_MISS = 0, |
| CACHE_HIT, |
| CACHE_MAX |
| }; |
| |
| // Keep the cache bounded to an arbitrary size. If it's too small, useful |
| // entries could be evicted when multiple .nexes are loaded at once. On the |
| // other hand, entries are not always claimed (and hence removed), so the size |
| // of the cache will likely saturate at its maximum size. |
| // Entries may not be claimed for two main reasons. 1) the NaCl process could |
| // be killed while it is loading. 2) the trusted NaCl plugin opens files using |
| // the code path but doesn't resolve them. |
| // TODO(ncbray) don't cache files that the plugin will not resolve. |
| const int kFilePathCacheSize = 100; |
| |
| const base::FilePath::StringType NaClIrtName() { |
| base::FilePath::StringType irt_name(FILE_PATH_LITERAL("nacl_irt_")); |
| |
| #if defined(ARCH_CPU_X86_FAMILY) |
| #if defined(ARCH_CPU_X86_64) |
| bool is64 = true; |
| #elif defined(OS_WIN) |
| bool is64 = (base::win::OSInfo::GetInstance()->wow64_status() == |
| base::win::OSInfo::WOW64_ENABLED); |
| #else |
| bool is64 = false; |
| #endif |
| if (is64) |
| irt_name.append(FILE_PATH_LITERAL("x86_64")); |
| else |
| irt_name.append(FILE_PATH_LITERAL("x86_32")); |
| |
| #elif defined(ARCH_CPU_ARMEL) |
| // TODO(mcgrathr): Eventually we'll need to distinguish arm32 vs thumb2. |
| // That may need to be based on the actual nexe rather than a static |
| // choice, which would require substantial refactoring. |
| irt_name.append(FILE_PATH_LITERAL("arm")); |
| #elif defined(ARCH_CPU_MIPSEL) |
| irt_name.append(FILE_PATH_LITERAL("mips32")); |
| #else |
| #error Add support for your architecture to NaCl IRT file selection |
| #endif |
| irt_name.append(FILE_PATH_LITERAL(".nexe")); |
| return irt_name; |
| } |
| |
| bool CheckEnvVar(const char* name, bool default_value) { |
| bool result = default_value; |
| const char* var = getenv(name); |
| if (var && strlen(var) > 0) { |
| result = var[0] != '0'; |
| } |
| return result; |
| } |
| |
| void ReadCache(const base::FilePath& filename, std::string* data) { |
| if (!base::ReadFileToString(filename, data)) { |
| // Zero-size data used as an in-band error code. |
| data->clear(); |
| } |
| } |
| |
| void WriteCache(const base::FilePath& filename, const Pickle* pickle) { |
| file_util::WriteFile(filename, static_cast<const char*>(pickle->data()), |
| pickle->size()); |
| } |
| |
| void RemoveCache(const base::FilePath& filename, |
| const base::Closure& callback) { |
| base::DeleteFile(filename, false); |
| content::BrowserThread::PostTask(content::BrowserThread::IO, FROM_HERE, |
| callback); |
| } |
| |
| void LogCacheQuery(ValidationCacheStatus status) { |
| UMA_HISTOGRAM_ENUMERATION("NaCl.ValidationCache.Query", status, CACHE_MAX); |
| } |
| |
| void LogCacheSet(ValidationCacheStatus status) { |
| // Bucket zero is reserved for future use. |
| UMA_HISTOGRAM_ENUMERATION("NaCl.ValidationCache.Set", status, CACHE_MAX); |
| } |
| |
| // Crash throttling parameters. |
| const size_t kMaxCrashesPerInterval = 3; |
| const int64 kCrashesIntervalInSeconds = 120; |
| |
| } // namespace |
| |
| namespace nacl { |
| |
| void OpenNaClExecutableImpl(const base::FilePath& file_path, |
| base::PlatformFile* file) { |
| // Get a file descriptor. On Windows, we need 'GENERIC_EXECUTE' in order to |
| // memory map the executable. |
| // IMPORTANT: This file descriptor must not have write access - that could |
| // allow a NaCl inner sandbox escape. |
| base::PlatformFileError error_code; |
| *file = base::CreatePlatformFile( |
| file_path, |
| (base::PLATFORM_FILE_OPEN | |
| base::PLATFORM_FILE_READ | |
| base::PLATFORM_FILE_EXECUTE), // Windows only flag. |
| NULL, |
| &error_code); |
| if (error_code != base::PLATFORM_FILE_OK) { |
| *file = base::kInvalidPlatformFileValue; |
| return; |
| } |
| // Check that the file does not reference a directory. Returning a descriptor |
| // to an extension directory could allow an outer sandbox escape. openat(...) |
| // could be used to traverse into the file system. |
| base::PlatformFileInfo file_info; |
| if (!base::GetPlatformFileInfo(*file, &file_info) || |
| file_info.is_directory) { |
| base::ClosePlatformFile(*file); |
| *file = base::kInvalidPlatformFileValue; |
| return; |
| } |
| } |
| |
| } // namespace nacl |
| |
| NaClBrowser::NaClBrowser() |
| : weak_factory_(this), |
| irt_platform_file_(base::kInvalidPlatformFileValue), |
| irt_filepath_(), |
| irt_state_(NaClResourceUninitialized), |
| validation_cache_file_path_(), |
| validation_cache_is_enabled_( |
| CheckEnvVar("NACL_VALIDATION_CACHE", |
| kValidationCacheEnabledByDefault)), |
| validation_cache_is_modified_(false), |
| validation_cache_state_(NaClResourceUninitialized), |
| path_cache_(kFilePathCacheSize), |
| ok_(true) { |
| } |
| |
| void NaClBrowser::SetDelegate(NaClBrowserDelegate* delegate) { |
| NaClBrowser* nacl_browser = NaClBrowser::GetInstance(); |
| nacl_browser->browser_delegate_.reset(delegate); |
| } |
| |
| NaClBrowserDelegate* NaClBrowser::GetDelegate() { |
| // The delegate is not owned by the IO thread. This accessor method can be |
| // called from other threads. |
| DCHECK(GetInstance()->browser_delegate_.get() != NULL); |
| return GetInstance()->browser_delegate_.get(); |
| } |
| |
| void NaClBrowser::EarlyStartup() { |
| DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO)); |
| InitIrtFilePath(); |
| InitValidationCacheFilePath(); |
| } |
| |
| NaClBrowser::~NaClBrowser() { |
| if (irt_platform_file_ != base::kInvalidPlatformFileValue) |
| base::ClosePlatformFile(irt_platform_file_); |
| } |
| |
| void NaClBrowser::InitIrtFilePath() { |
| // Allow the IRT library to be overridden via an environment |
| // variable. This allows the NaCl/Chromium integration bot to |
| // specify a newly-built IRT rather than using a prebuilt one |
| // downloaded via Chromium's DEPS file. We use the same environment |
| // variable that the standalone NaCl PPAPI plugin accepts. |
| const char* irt_path_var = getenv("NACL_IRT_LIBRARY"); |
| if (irt_path_var != NULL) { |
| base::FilePath::StringType path_string( |
| irt_path_var, const_cast<const char*>(strchr(irt_path_var, '\0'))); |
| irt_filepath_ = base::FilePath(path_string); |
| } else { |
| base::FilePath plugin_dir; |
| if (!browser_delegate_->GetPluginDirectory(&plugin_dir)) { |
| DLOG(ERROR) << "Failed to locate the plugins directory, NaCl disabled."; |
| MarkAsFailed(); |
| return; |
| } |
| irt_filepath_ = plugin_dir.Append(NaClIrtName()); |
| } |
| } |
| |
| #if defined(OS_WIN) |
| bool NaClBrowser::GetNaCl64ExePath(base::FilePath* exe_path) { |
| base::FilePath module_path; |
| if (!PathService::Get(base::FILE_MODULE, &module_path)) { |
| LOG(ERROR) << "NaCl process launch failed: could not resolve module"; |
| return false; |
| } |
| *exe_path = module_path.DirName().Append(L"nacl64"); |
| return true; |
| } |
| #endif |
| |
| NaClBrowser* NaClBrowser::GetInstance() { |
| return Singleton<NaClBrowser>::get(); |
| } |
| |
| bool NaClBrowser::IsReady() const { |
| return (IsOk() && |
| irt_state_ == NaClResourceReady && |
| validation_cache_state_ == NaClResourceReady); |
| } |
| |
| bool NaClBrowser::IsOk() const { |
| return ok_; |
| } |
| |
| base::PlatformFile NaClBrowser::IrtFile() const { |
| DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO)); |
| CHECK_EQ(irt_state_, NaClResourceReady); |
| CHECK_NE(irt_platform_file_, base::kInvalidPlatformFileValue); |
| return irt_platform_file_; |
| } |
| |
| void NaClBrowser::EnsureAllResourcesAvailable() { |
| DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO)); |
| EnsureIrtAvailable(); |
| EnsureValidationCacheAvailable(); |
| } |
| |
| // Load the IRT async. |
| void NaClBrowser::EnsureIrtAvailable() { |
| DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO)); |
| if (IsOk() && irt_state_ == NaClResourceUninitialized) { |
| irt_state_ = NaClResourceRequested; |
| // TODO(ncbray) use blocking pool. |
| if (!base::FileUtilProxy::CreateOrOpen( |
| content::BrowserThread::GetMessageLoopProxyForThread( |
| content::BrowserThread::FILE) |
| .get(), |
| irt_filepath_, |
| base::PLATFORM_FILE_OPEN | base::PLATFORM_FILE_READ, |
| base::Bind(&NaClBrowser::OnIrtOpened, |
| weak_factory_.GetWeakPtr()))) { |
| LOG(ERROR) << "Internal error, NaCl disabled."; |
| MarkAsFailed(); |
| } |
| } |
| } |
| |
| void NaClBrowser::OnIrtOpened(base::PlatformFileError error_code, |
| base::PassPlatformFile file, |
| bool created) { |
| DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO)); |
| DCHECK_EQ(irt_state_, NaClResourceRequested); |
| DCHECK(!created); |
| if (error_code == base::PLATFORM_FILE_OK) { |
| irt_platform_file_ = file.ReleaseValue(); |
| } else { |
| LOG(ERROR) << "Failed to open NaCl IRT file \"" |
| << irt_filepath_.LossyDisplayName() |
| << "\": " << error_code; |
| MarkAsFailed(); |
| } |
| irt_state_ = NaClResourceReady; |
| CheckWaiting(); |
| } |
| |
| void NaClBrowser::FireGdbDebugStubPortOpened(int port) { |
| content::BrowserThread::PostTask( |
| content::BrowserThread::IO, |
| FROM_HERE, |
| base::Bind(debug_stub_port_listener_, port)); |
| } |
| |
| bool NaClBrowser::HasGdbDebugStubPortListener() { |
| return !debug_stub_port_listener_.is_null(); |
| } |
| |
| void NaClBrowser::SetGdbDebugStubPortListener( |
| base::Callback<void(int)> listener) { |
| debug_stub_port_listener_ = listener; |
| } |
| |
| void NaClBrowser::ClearGdbDebugStubPortListener() { |
| debug_stub_port_listener_.Reset(); |
| } |
| |
| void NaClBrowser::InitValidationCacheFilePath() { |
| // Determine where the validation cache resides in the file system. It |
| // exists in Chrome's cache directory and is not tied to any specific |
| // profile. |
| // Start by finding the user data directory. |
| base::FilePath user_data_dir; |
| if (!browser_delegate_->GetUserDirectory(&user_data_dir)) { |
| RunWithoutValidationCache(); |
| return; |
| } |
| // The cache directory may or may not be the user data directory. |
| base::FilePath cache_file_path; |
| browser_delegate_->GetCacheDirectory(&cache_file_path); |
| // Append the base file name to the cache directory. |
| |
| validation_cache_file_path_ = |
| cache_file_path.Append(kValidationCacheFileName); |
| } |
| |
| void NaClBrowser::EnsureValidationCacheAvailable() { |
| DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO)); |
| if (IsOk() && validation_cache_state_ == NaClResourceUninitialized) { |
| if (ValidationCacheIsEnabled()) { |
| validation_cache_state_ = NaClResourceRequested; |
| |
| // Structure for carrying data between the callbacks. |
| std::string* data = new std::string(); |
| // We can get away not giving this a sequence ID because this is the first |
| // task and further file access will not occur until after we get a |
| // response. |
| if (!content::BrowserThread::PostBlockingPoolTaskAndReply( |
| FROM_HERE, |
| base::Bind(ReadCache, validation_cache_file_path_, data), |
| base::Bind(&NaClBrowser::OnValidationCacheLoaded, |
| weak_factory_.GetWeakPtr(), |
| base::Owned(data)))) { |
| RunWithoutValidationCache(); |
| } |
| } else { |
| RunWithoutValidationCache(); |
| } |
| } |
| } |
| |
| void NaClBrowser::OnValidationCacheLoaded(const std::string *data) { |
| DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO)); |
| // Did the cache get cleared before the load completed? If so, ignore the |
| // incoming data. |
| if (validation_cache_state_ == NaClResourceReady) |
| return; |
| |
| if (data->size() == 0) { |
| // No file found. |
| validation_cache_.Reset(); |
| } else { |
| Pickle pickle(data->data(), data->size()); |
| validation_cache_.Deserialize(&pickle); |
| } |
| validation_cache_state_ = NaClResourceReady; |
| CheckWaiting(); |
| } |
| |
| void NaClBrowser::RunWithoutValidationCache() { |
| // Be paranoid. |
| validation_cache_.Reset(); |
| validation_cache_is_enabled_ = false; |
| validation_cache_state_ = NaClResourceReady; |
| CheckWaiting(); |
| } |
| |
| void NaClBrowser::CheckWaiting() { |
| DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO)); |
| if (!IsOk() || IsReady()) { |
| // Queue the waiting tasks into the message loop. This helps avoid |
| // re-entrancy problems that could occur if the closure was invoked |
| // directly. For example, this could result in use-after-free of the |
| // process host. |
| for (std::vector<base::Closure>::iterator iter = waiting_.begin(); |
| iter != waiting_.end(); ++iter) { |
| base::MessageLoop::current()->PostTask(FROM_HERE, *iter); |
| } |
| waiting_.clear(); |
| } |
| } |
| |
| void NaClBrowser::MarkAsFailed() { |
| ok_ = false; |
| CheckWaiting(); |
| } |
| |
| void NaClBrowser::WaitForResources(const base::Closure& reply) { |
| waiting_.push_back(reply); |
| EnsureAllResourcesAvailable(); |
| CheckWaiting(); |
| } |
| |
| const base::FilePath& NaClBrowser::GetIrtFilePath() { |
| return irt_filepath_; |
| } |
| |
| void NaClBrowser::PutFilePath(const base::FilePath& path, uint64* file_token_lo, |
| uint64* file_token_hi) { |
| DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO)); |
| while (true) { |
| uint64 file_token[2] = {base::RandUint64(), base::RandUint64()}; |
| // A zero file_token indicates there is no file_token, if we get zero, ask |
| // for another number. |
| if (file_token[0] != 0 || file_token[1] != 0) { |
| // If the file_token is in use, ask for another number. |
| std::string key(reinterpret_cast<char*>(file_token), sizeof(file_token)); |
| PathCacheType::iterator iter = path_cache_.Peek(key); |
| if (iter == path_cache_.end()) { |
| path_cache_.Put(key, path); |
| *file_token_lo = file_token[0]; |
| *file_token_hi = file_token[1]; |
| break; |
| } |
| } |
| } |
| } |
| |
| bool NaClBrowser::GetFilePath(uint64 file_token_lo, uint64 file_token_hi, |
| base::FilePath* path) { |
| DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO)); |
| uint64 file_token[2] = {file_token_lo, file_token_hi}; |
| std::string key(reinterpret_cast<char*>(file_token), sizeof(file_token)); |
| PathCacheType::iterator iter = path_cache_.Peek(key); |
| if (iter == path_cache_.end()) { |
| *path = base::FilePath(FILE_PATH_LITERAL("")); |
| return false; |
| } |
| *path = iter->second; |
| path_cache_.Erase(iter); |
| return true; |
| } |
| |
| |
| bool NaClBrowser::QueryKnownToValidate(const std::string& signature, |
| bool off_the_record) { |
| DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO)); |
| if (off_the_record) { |
| // If we're off the record, don't reorder the main cache. |
| return validation_cache_.QueryKnownToValidate(signature, false) || |
| off_the_record_validation_cache_.QueryKnownToValidate(signature, true); |
| } else { |
| bool result = validation_cache_.QueryKnownToValidate(signature, true); |
| LogCacheQuery(result ? CACHE_HIT : CACHE_MISS); |
| // Queries can modify the MRU order of the cache. |
| MarkValidationCacheAsModified(); |
| return result; |
| } |
| } |
| |
| void NaClBrowser::SetKnownToValidate(const std::string& signature, |
| bool off_the_record) { |
| DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO)); |
| if (off_the_record) { |
| off_the_record_validation_cache_.SetKnownToValidate(signature); |
| } else { |
| validation_cache_.SetKnownToValidate(signature); |
| // The number of sets should be equal to the number of cache misses, minus |
| // validation failures and successful validations where stubout occurs. |
| LogCacheSet(CACHE_HIT); |
| MarkValidationCacheAsModified(); |
| } |
| } |
| |
| void NaClBrowser::ClearValidationCache(const base::Closure& callback) { |
| DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO)); |
| // Note: this method may be called before EnsureValidationCacheAvailable has |
| // been invoked. In other words, this method may be called before any NaCl |
| // processes have been created. This method must succeed and invoke the |
| // callback in such a case. If it does not invoke the callback, Chrome's UI |
| // will hang in that case. |
| validation_cache_.Reset(); |
| off_the_record_validation_cache_.Reset(); |
| |
| if (validation_cache_file_path_.empty()) { |
| // Can't figure out what file to remove, but don't drop the callback. |
| content::BrowserThread::PostTask(content::BrowserThread::IO, FROM_HERE, |
| callback); |
| } else { |
| // Delegate the removal of the cache from the filesystem to another thread |
| // to avoid blocking the IO thread. |
| // This task is dispatched immediately, not delayed and coalesced, because |
| // the user interface for cache clearing is likely waiting for the callback. |
| // In addition, we need to make sure the cache is actually cleared before |
| // invoking the callback to meet the implicit guarantees of the UI. |
| content::BrowserThread::PostBlockingPoolSequencedTask( |
| kValidationCacheSequenceName, |
| FROM_HERE, |
| base::Bind(RemoveCache, validation_cache_file_path_, callback)); |
| } |
| |
| // Make sure any delayed tasks to persist the cache to the filesystem are |
| // squelched. |
| validation_cache_is_modified_ = false; |
| |
| // If the cache is cleared before it is loaded from the filesystem, act as if |
| // we just loaded an empty cache. |
| if (validation_cache_state_ != NaClResourceReady) { |
| validation_cache_state_ = NaClResourceReady; |
| CheckWaiting(); |
| } |
| } |
| |
| void NaClBrowser::MarkValidationCacheAsModified() { |
| if (!validation_cache_is_modified_) { |
| // Wait before persisting to disk. This can coalesce multiple cache |
| // modifications info a single disk write. |
| base::MessageLoop::current()->PostDelayedTask( |
| FROM_HERE, |
| base::Bind(&NaClBrowser::PersistValidationCache, |
| weak_factory_.GetWeakPtr()), |
| base::TimeDelta::FromMilliseconds(kValidationCacheCoalescingTimeMS)); |
| validation_cache_is_modified_ = true; |
| } |
| } |
| |
| void NaClBrowser::PersistValidationCache() { |
| DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO)); |
| // validation_cache_is_modified_ may be false if the cache was cleared while |
| // this delayed task was pending. |
| // validation_cache_file_path_ may be empty if something went wrong during |
| // initialization. |
| if (validation_cache_is_modified_ && !validation_cache_file_path_.empty()) { |
| Pickle* pickle = new Pickle(); |
| validation_cache_.Serialize(pickle); |
| |
| // Pass the serialized data to another thread to write to disk. File IO is |
| // not allowed on the IO thread (which is the thread this method runs on) |
| // because it can degrade the responsiveness of the browser. |
| // The task is sequenced so that multiple writes happen in order. |
| content::BrowserThread::PostBlockingPoolSequencedTask( |
| kValidationCacheSequenceName, |
| FROM_HERE, |
| base::Bind(WriteCache, validation_cache_file_path_, |
| base::Owned(pickle))); |
| } |
| validation_cache_is_modified_ = false; |
| } |
| |
| void NaClBrowser::OnProcessCrashed() { |
| DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO)); |
| if (crash_times_.size() == kMaxCrashesPerInterval) { |
| crash_times_.pop_front(); |
| } |
| base::Time time = base::Time::Now(); |
| crash_times_.push_back(time); |
| } |
| |
| bool NaClBrowser::IsThrottled() { |
| DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO)); |
| if (crash_times_.size() != kMaxCrashesPerInterval) { |
| return false; |
| } |
| base::TimeDelta delta = base::Time::Now() - crash_times_.front(); |
| return delta.InSeconds() <= kCrashesIntervalInSeconds; |
| } |