Add retry logic to V8Initializer snapshot loading files for suspected A/V problem.

gin/v8_initializer.cc

 // Copyright 2013 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 "gin/v8_initializer.h"
 
 #include "base/basictypes.h"
 #include "base/files/file.h"
 #include "base/files/file_path.h"
 #include "base/files/memory_mapped_file.h"
 #include "base/logging.h"
+#include "base/metrics/histogram.h"
 #include "base/rand_util.h"
 #include "base/strings/sys_string_conversions.h"
+#include "base/threading/platform_thread.h"
+#include "base/time/time.h"
 #include "crypto/sha2.h"
 
 #if defined(V8_USE_EXTERNAL_STARTUP_DATA)
 #if defined(OS_MACOSX)
 #include "base/mac/foundation_util.h"
 #endif  // OS_MACOSX
 #include "base/path_service.h"
 #endif  // V8_USE_EXTERNAL_STARTUP_DATA
 
 namespace gin {
@@ skipping 11 matching lines @@
 #elif defined(OS_POSIX)
     base::DIR_EXE;
 #elif defined(OS_WIN)
     base::DIR_MODULE;
 #endif  // OS_ANDROID
 #endif  // !OS_MACOSX
 
 const char kNativesFileName[] = "natives_blob.bin";
 const char kSnapshotFileName[] = "snapshot_blob.bin";
 
+// Constants for snapshot loading retries taken from:
+//   https://support.microsoft.com/en-us/kb/316609.
+const int kMaxOpenAttempts = 5;
+const int kOpenRetryDelayMillis = 250;
+
 void GetV8FilePaths(base::FilePath* natives_path_out,
                     base::FilePath* snapshot_path_out) {
 #if !defined(OS_MACOSX)
   base::FilePath data_path;
   PathService::Get(kV8SnapshotBasePathKey, &data_path);
   DCHECK(!data_path.empty());
 
   *natives_path_out = data_path.AppendASCII(kNativesFileName);
   *snapshot_path_out = data_path.AppendASCII(kSnapshotFileName);
 #else   // !defined(OS_MACOSX)
   base::ScopedCFTypeRef<CFStringRef> natives_file_name(
       base::SysUTF8ToCFStringRef(kNativesFileName));
   *natives_path_out =
       base::mac::PathForFrameworkBundleResource(natives_file_name);
   base::ScopedCFTypeRef<CFStringRef> snapshot_file_name(
       base::SysUTF8ToCFStringRef(kSnapshotFileName));
   *snapshot_path_out =
       base::mac::PathForFrameworkBundleResource(snapshot_file_name);
   DCHECK(!natives_path_out->empty());
   DCHECK(!snapshot_path_out->empty());
 #endif  // !defined(OS_MACOSX)
 }
 
-bool MapV8Files(base::File natives_file,
-                base::File snapshot_file,
-                base::MemoryMappedFile::Region natives_region =
-                    base::MemoryMappedFile::Region::kWholeFile,
-                base::MemoryMappedFile::Region snapshot_region =
-                    base::MemoryMappedFile::Region::kWholeFile) {
+static bool MapV8Files(base::File natives_file,
+                       base::File snapshot_file,
+                       base::MemoryMappedFile::Region natives_region =
+                           base::MemoryMappedFile::Region::kWholeFile,
+                       base::MemoryMappedFile::Region snapshot_region =
+                           base::MemoryMappedFile::Region::kWholeFile) {
   g_mapped_natives = new base::MemoryMappedFile;
   if (!g_mapped_natives->IsValid()) {
     if (!g_mapped_natives->Initialize(natives_file.Pass(), natives_region)) {
       delete g_mapped_natives;
       g_mapped_natives = NULL;
       LOG(FATAL) << "Couldn't mmap v8 natives data file";
       return false;
     }
   }
 
   g_mapped_snapshot = new base::MemoryMappedFile;
   if (!g_mapped_snapshot->IsValid()) {
     if (!g_mapped_snapshot->Initialize(snapshot_file.Pass(), snapshot_region)) {
       delete g_mapped_snapshot;
       g_mapped_snapshot = NULL;
       LOG(ERROR) << "Couldn't mmap v8 snapshot data file";
       return false;
     }
   }
 
   return true;
 }
 
+static bool OpenV8File(const base::FilePath& path,
+                       int flags,
+                       base::File& file) {
+  // Re-try logic here is motivated by http://crbug.com/479537
+  // for A/V on Windows (https://support.microsoft.com/en-us/kb/316609).
+
+  // These match tools/metrics/histograms.xml
+  enum OpenV8FileResult {
+    OPENED = 0,
+    OPENED_RETRY,
+    FAILED_IN_USE,
+    FAILED_OTHER,
+    MAX_VALUE
+  };
+
+  OpenV8FileResult result = OpenV8FileResult::FAILED_IN_USE;
+  for (int attempt = 0; attempt < kMaxOpenAttempts; attempt++) {
+    file.Initialize(path, flags);
+    if (file.IsValid()) {
+      if (attempt == 0) {
+        result = OpenV8FileResult::OPENED;
+        break;
+      } else {
+        result = OpenV8FileResult::OPENED_RETRY;
+        break;
+      }
+    } else if (file.error_details() != base::File::FILE_ERROR_IN_USE) {
+      result = OpenV8FileResult::FAILED_OTHER;
+      break;
+    } else if (kMaxOpenAttempts - 1 != attempt) {
+      base::PlatformThread::Sleep(
+          base::TimeDelta::FromMilliseconds(kOpenRetryDelayMillis));
+    }
+  }
+
+  UMA_HISTOGRAM_ENUMERATION("V8.Initializer.OpenV8File.Result",
+                            result,
+                            OpenV8FileResult::MAX_VALUE);
+
+  return result == OpenV8FileResult::OPENED
+         || result == OpenV8FileResult::OPENED_RETRY;
+}
+
 #if defined(V8_VERIFY_EXTERNAL_STARTUP_DATA)
 bool VerifyV8SnapshotFile(base::MemoryMappedFile* snapshot_file,
                           const unsigned char* fingerprint) {
   unsigned char output[crypto::kSHA256Length];
   crypto::SHA256HashString(
       base::StringPiece(reinterpret_cast<const char*>(snapshot_file->data()),
                         snapshot_file->length()),
       output, sizeof(output));
   return !memcmp(fingerprint, output, sizeof(output));
 }
 #endif  // V8_VERIFY_EXTERNAL_STARTUP_DATA
 #endif  // V8_USE_EXTERNAL_STARTUP_DATA
 
 bool GenerateEntropy(unsigned char* buffer, size_t amount) {
   base::RandBytes(buffer, amount);
   return true;
 }
 
 }  // namespace
 
 #if defined(V8_USE_EXTERNAL_STARTUP_DATA)
 #if defined(V8_VERIFY_EXTERNAL_STARTUP_DATA)
 // Defined in gen/gin/v8_snapshot_fingerprint.cc
 extern const unsigned char g_natives_fingerprint[];
 extern const unsigned char g_snapshot_fingerprint[];
 #endif  // V8_VERIFY_EXTERNAL_STARTUP_DATA
 
 // static
 bool V8Initializer::LoadV8Snapshot() {
+
+  enum LoadV8SnapshotResult {
+    SUCCESS = 0,
+    FAILED_OPEN,
+    FAILED_MAP,
+    FAILED_VERIFY,
+    MAX_VALUE
+  };
+
   if (g_mapped_natives && g_mapped_snapshot)
     return true;
 
   base::FilePath natives_data_path;
   base::FilePath snapshot_data_path;
   GetV8FilePaths(&natives_data_path, &snapshot_data_path);
 
+  base::File natives_file;
+  base::File snapshot_file;
   int flags = base::File::FLAG_OPEN | base::File::FLAG_READ;
-  if (!MapV8Files(base::File(natives_data_path, flags),
-                  base::File(snapshot_data_path, flags)))
-    return false;
 
+  LoadV8SnapshotResult result;
+  if (!OpenV8File(natives_data_path, flags, natives_file) ||
+      !OpenV8File(snapshot_data_path, flags, snapshot_file)) {
+    result = LoadV8SnapshotResult::FAILED_OPEN;
+  } else if (!MapV8Files(natives_file.Pass(), snapshot_file.Pass())) {
+    result = LoadV8SnapshotResult::FAILED_MAP;
 #if defined(V8_VERIFY_EXTERNAL_STARTUP_DATA)
-  // TODO(oth) Remove these temporary CHECKs once http://crbug.com/479537 is
-  // fixed. These are just here to identify whether canary failures are
-  // due to verification or file/vm failures.
-  bool natives_ok =
-      VerifyV8SnapshotFile(g_mapped_natives, g_natives_fingerprint);
-  CHECK(natives_ok);
-  bool snapshot_ok =
-      VerifyV8SnapshotFile(g_mapped_snapshot, g_snapshot_fingerprint);
-  CHECK(snapshot_ok);
-  return natives_ok && snapshot_ok;
-#else
-  return true;
+  } else if (!VerifyV8SnapshotFile(g_mapped_natives, g_natives_fingerprint) ||
+             !VerifyV8SnapshotFile(g_mapped_snapshot, g_snapshot_fingerprint)) {
+    result = LoadV8SnapshotResult::FAILED_VERIFY;
 #endif  // V8_VERIFY_EXTERNAL_STARTUP_DATA
+  } else {
+    result = LoadV8SnapshotResult::SUCCESS;
+  }
+
+  UMA_HISTOGRAM_ENUMERATION("V8.Initializer.LoadV8Snapshot.Result",
+                            result,
+                            LoadV8SnapshotResult::MAX_VALUE);
+  return result == LoadV8SnapshotResult::SUCCESS;
 }
 
 // static
 bool V8Initializer::LoadV8SnapshotFromFD(base::PlatformFile natives_pf,
                                          int64 natives_offset,
                                          int64 natives_size,
                                          base::PlatformFile snapshot_pf,
                                          int64 snapshot_offset,
                                          int64 snapshot_size) {
   if (g_mapped_natives && g_mapped_snapshot)
@@ skipping 18 matching lines @@
 }
 
 // static
 bool V8Initializer::OpenV8FilesForChildProcesses(
     base::PlatformFile* natives_fd_out,
     base::PlatformFile* snapshot_fd_out) {
   base::FilePath natives_data_path;
   base::FilePath snapshot_data_path;
   GetV8FilePaths(&natives_data_path, &snapshot_data_path);
 
+  base::File natives_data_file;
+  base::File snapshot_data_file;
   int file_flags = base::File::FLAG_OPEN | base::File::FLAG_READ;
-  base::File natives_data_file(natives_data_path, file_flags);
-  base::File snapshot_data_file(snapshot_data_path, file_flags);
 
-  if (!natives_data_file.IsValid() || !snapshot_data_file.IsValid())
-    return false;
-
-  *natives_fd_out = natives_data_file.TakePlatformFile();
-  *snapshot_fd_out = snapshot_data_file.TakePlatformFile();
-  return true;
+  bool success = OpenV8File(natives_data_path, file_flags, natives_data_file) &&
+                 OpenV8File(snapshot_data_path, file_flags, snapshot_data_file);
+  if (success) {
+    *natives_fd_out = natives_data_file.TakePlatformFile();
+    *snapshot_fd_out = snapshot_data_file.TakePlatformFile();
+  }
+  return success;
 }
 
 #endif  // V8_USE_EXTERNAL_STARTUP_DATA
 
 // static
 void V8Initializer::Initialize(gin::IsolateHolder::ScriptMode mode) {
   static bool v8_is_initialized = false;
   if (v8_is_initialized)
     return;
 
@@ skipping 32 matching lines @@
     *natives_size_out = *snapshot_size_out = 0;
     return;
   }
   *natives_data_out = reinterpret_cast<const char*>(g_mapped_natives->data());
   *snapshot_data_out = reinterpret_cast<const char*>(g_mapped_snapshot->data());
   *natives_size_out = static_cast<int>(g_mapped_natives->length());
   *snapshot_size_out = static_cast<int>(g_mapped_snapshot->length());
 }
 
 }  // namespace gin