base/sync_socket_win.cc - gn - Git at Google

 // 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 "base/sync_socket.h"

 #include <limits.h>
 #include <stddef.h>

 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/rand_util.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/win/scoped_handle.h"

 namespace base {

 using win::ScopedHandle;

 namespace {
 // IMPORTANT: do not change how this name is generated because it will break
 // in sandboxed scenarios as we might have by-name policies that allow pipe
 // creation. Also keep the secure random number generation.
 const wchar_t kPipeNameFormat[] = L"\\\\.\\pipe\\chrome.sync.%u.%u.%lu";
 const size_t kPipePathMax =  arraysize(kPipeNameFormat) + (3 * 10) + 1;

 // To avoid users sending negative message lengths to Send/Receive
 // we clamp message lengths, which are size_t, to no more than INT_MAX.
 const size_t kMaxMessageLength = static_cast<size_t>(INT_MAX);

 const int kOutBufferSize = 4096;
 const int kInBufferSize = 4096;
 const int kDefaultTimeoutMilliSeconds = 1000;

 bool CreatePairImpl(HANDLE* socket_a, HANDLE* socket_b, bool overlapped) {
   DCHECK_NE(socket_a, socket_b);
   DCHECK_EQ(*socket_a, SyncSocket::kInvalidHandle);
   DCHECK_EQ(*socket_b, SyncSocket::kInvalidHandle);

   wchar_t name[kPipePathMax];
   ScopedHandle handle_a;
   DWORD flags = PIPE_ACCESS_DUPLEX | FILE_FLAG_FIRST_PIPE_INSTANCE;
   if (overlapped)
     flags |= FILE_FLAG_OVERLAPPED;

   do {
     unsigned long rnd_name;
     RandBytes(&rnd_name, sizeof(rnd_name));

     swprintf(name, kPipePathMax,
              kPipeNameFormat,
              GetCurrentProcessId(),
              GetCurrentThreadId(),
              rnd_name);

     handle_a.Set(CreateNamedPipeW(
         name,
         flags,
         PIPE_TYPE_BYTE | PIPE_READMODE_BYTE,
         1,
         kOutBufferSize,
         kInBufferSize,
         kDefaultTimeoutMilliSeconds,
         NULL));
   } while (!handle_a.IsValid() &&
            (GetLastError() == ERROR_PIPE_BUSY));

   if (!handle_a.IsValid()) {
     NOTREACHED();
     return false;
   }

   // The SECURITY_ANONYMOUS flag means that the server side (handle_a) cannot
   // impersonate the client (handle_b). This allows us not to care which side
   // ends up in which side of a privilege boundary.
   flags = SECURITY_SQOS_PRESENT | SECURITY_ANONYMOUS;
   if (overlapped)
     flags |= FILE_FLAG_OVERLAPPED;

   ScopedHandle handle_b(CreateFileW(name,
                                     GENERIC_READ | GENERIC_WRITE,
                                     0,          // no sharing.
                                     NULL,       // default security attributes.
                                     OPEN_EXISTING,  // opens existing pipe.
                                     flags,
                                     NULL));     // no template file.
   if (!handle_b.IsValid()) {
     DPLOG(ERROR) << "CreateFileW failed";
     return false;
   }

   if (!ConnectNamedPipe(handle_a.Get(), NULL)) {
     DWORD error = GetLastError();
     if (error != ERROR_PIPE_CONNECTED) {
       DPLOG(ERROR) << "ConnectNamedPipe failed";
       return false;
     }
   }

   *socket_a = handle_a.Take();
   *socket_b = handle_b.Take();

   return true;
 }

 // Inline helper to avoid having the cast everywhere.
 DWORD GetNextChunkSize(size_t current_pos, size_t max_size) {
   // The following statement is for 64 bit portability.
   return static_cast<DWORD>(((max_size - current_pos) <= UINT_MAX) ?
       (max_size - current_pos) : UINT_MAX);
 }

 // Template function that supports calling ReadFile or WriteFile in an
 // overlapped fashion and waits for IO completion.  The function also waits
 // on an event that can be used to cancel the operation.  If the operation
 // is cancelled, the function returns and closes the relevant socket object.
 template <typename BufferType, typename Function>
 size_t CancelableFileOperation(Function operation,
                                HANDLE file,
                                BufferType* buffer,
                                size_t length,
                                WaitableEvent* io_event,
                                WaitableEvent* cancel_event,
                                CancelableSyncSocket* socket,
                                DWORD timeout_in_ms) {
   AssertBlockingAllowed();
   // The buffer must be byte size or the length check won't make much sense.
   static_assert(sizeof(buffer[0]) == sizeof(char), "incorrect buffer type");
   DCHECK_GT(length, 0u);
   DCHECK_LE(length, kMaxMessageLength);
   DCHECK_NE(file, SyncSocket::kInvalidHandle);

   // Track the finish time so we can calculate the timeout as data is read.
   TimeTicks current_time, finish_time;
   if (timeout_in_ms != INFINITE) {
     current_time = TimeTicks::Now();
     finish_time =
         current_time + base::TimeDelta::FromMilliseconds(timeout_in_ms);
   }

   size_t count = 0;
   do {
     // The OVERLAPPED structure will be modified by ReadFile or WriteFile.
     OVERLAPPED ol = { 0 };
     ol.hEvent = io_event->handle();

     const DWORD chunk = GetNextChunkSize(count, length);
     // This is either the ReadFile or WriteFile call depending on whether
     // we're receiving or sending data.
     DWORD len = 0;
     const BOOL operation_ok = operation(
         file, static_cast<BufferType*>(buffer) + count, chunk, &len, &ol);
     if (!operation_ok) {
       if (::GetLastError() == ERROR_IO_PENDING) {
         HANDLE events[] = { io_event->handle(), cancel_event->handle() };
         const int wait_result = WaitForMultipleObjects(
             arraysize(events), events, FALSE,
             timeout_in_ms == INFINITE ?
                 timeout_in_ms :
                 static_cast<DWORD>(
                     (finish_time - current_time).InMilliseconds()));
         if (wait_result != WAIT_OBJECT_0 + 0) {
           // CancelIo() doesn't synchronously cancel outstanding IO, only marks
           // outstanding IO for cancellation. We must call GetOverlappedResult()
           // below to ensure in flight writes complete before returning.
           CancelIo(file);
         }

         // We set the |bWait| parameter to TRUE for GetOverlappedResult() to
         // ensure writes are complete before returning.
         if (!GetOverlappedResult(file, &ol, &len, TRUE))
           len = 0;

         if (wait_result == WAIT_OBJECT_0 + 1) {
           DVLOG(1) << "Shutdown was signaled. Closing socket.";
           socket->Close();
           return count;
         }

         // Timeouts will be handled by the while() condition below since
         // GetOverlappedResult() may complete successfully after CancelIo().
         DCHECK(wait_result == WAIT_OBJECT_0 + 0 || wait_result == WAIT_TIMEOUT);
       } else {
         break;
       }
     }

     count += len;

     // Quit the operation if we can't write/read anymore.
     if (len != chunk)
       break;

     // Since TimeTicks::Now() is expensive, only bother updating the time if we
     // have more work to do.
     if (timeout_in_ms != INFINITE && count < length)
       current_time = base::TimeTicks::Now();
   } while (count < length &&
            (timeout_in_ms == INFINITE || current_time < finish_time));

   return count;
 }

 }  // namespace

 #if defined(COMPONENT_BUILD)
 const SyncSocket::Handle SyncSocket::kInvalidHandle = INVALID_HANDLE_VALUE;
 #endif

 SyncSocket::SyncSocket() : handle_(kInvalidHandle) {}

 SyncSocket::~SyncSocket() {
   Close();
 }

 // static
 bool SyncSocket::CreatePair(SyncSocket* socket_a, SyncSocket* socket_b) {
   return CreatePairImpl(&socket_a->handle_, &socket_b->handle_, false);
 }

 // static
 SyncSocket::Handle SyncSocket::UnwrapHandle(
     const TransitDescriptor& descriptor) {
   return descriptor;
 }

 bool SyncSocket::PrepareTransitDescriptor(ProcessHandle peer_process_handle,
                                           TransitDescriptor* descriptor) {
   DCHECK(descriptor);
   if (!::DuplicateHandle(GetCurrentProcess(), handle(), peer_process_handle,
                          descriptor, 0, FALSE, DUPLICATE_SAME_ACCESS)) {
     DPLOG(ERROR) << "Cannot duplicate socket handle for peer process.";
     return false;
   }
   return true;
 }

 bool SyncSocket::Close() {
   if (handle_ == kInvalidHandle)
     return true;

   const BOOL result = CloseHandle(handle_);
   handle_ = kInvalidHandle;
   return result == TRUE;
 }

 size_t SyncSocket::Send(const void* buffer, size_t length) {
   AssertBlockingAllowed();
   DCHECK_GT(length, 0u);
   DCHECK_LE(length, kMaxMessageLength);
   DCHECK_NE(handle_, kInvalidHandle);
   size_t count = 0;
   while (count < length) {
     DWORD len;
     DWORD chunk = GetNextChunkSize(count, length);
     if (::WriteFile(handle_, static_cast<const char*>(buffer) + count, chunk,
                     &len, NULL) == FALSE) {
       return count;
     }
     count += len;
   }
   return count;
 }

 size_t SyncSocket::ReceiveWithTimeout(void* buffer,
                                       size_t length,
                                       TimeDelta timeout) {
   NOTIMPLEMENTED();
   return 0;
 }

 size_t SyncSocket::Receive(void* buffer, size_t length) {
   AssertBlockingAllowed();
   DCHECK_GT(length, 0u);
   DCHECK_LE(length, kMaxMessageLength);
   DCHECK_NE(handle_, kInvalidHandle);
   size_t count = 0;
   while (count < length) {
     DWORD len;
     DWORD chunk = GetNextChunkSize(count, length);
     if (::ReadFile(handle_, static_cast<char*>(buffer) + count, chunk, &len,
                    NULL) == FALSE) {
       return count;
     }
     count += len;
   }
   return count;
 }

 size_t SyncSocket::Peek() {
   DWORD available = 0;
   PeekNamedPipe(handle_, NULL, 0, NULL, &available, NULL);
   return available;
 }

 SyncSocket::Handle SyncSocket::Release() {
   Handle r = handle_;
   handle_ = kInvalidHandle;
   return r;
 }

 CancelableSyncSocket::CancelableSyncSocket()
     : shutdown_event_(base::WaitableEvent::ResetPolicy::MANUAL,
                       base::WaitableEvent::InitialState::NOT_SIGNALED),
       file_operation_(base::WaitableEvent::ResetPolicy::MANUAL,
                       base::WaitableEvent::InitialState::NOT_SIGNALED) {}

 CancelableSyncSocket::CancelableSyncSocket(Handle handle)
     : SyncSocket(handle),
       shutdown_event_(base::WaitableEvent::ResetPolicy::MANUAL,
                       base::WaitableEvent::InitialState::NOT_SIGNALED),
       file_operation_(base::WaitableEvent::ResetPolicy::MANUAL,
                       base::WaitableEvent::InitialState::NOT_SIGNALED) {}

 bool CancelableSyncSocket::Shutdown() {
   // This doesn't shut down the pipe immediately, but subsequent Receive or Send
   // methods will fail straight away.
   shutdown_event_.Signal();
   return true;
 }

 bool CancelableSyncSocket::Close() {
   const bool result = SyncSocket::Close();
   shutdown_event_.Reset();
   return result;
 }

 size_t CancelableSyncSocket::Send(const void* buffer, size_t length) {
   static const DWORD kWaitTimeOutInMs = 500;
   return CancelableFileOperation(
       &::WriteFile, handle_, reinterpret_cast<const char*>(buffer), length,
       &file_operation_, &shutdown_event_, this, kWaitTimeOutInMs);
 }

 size_t CancelableSyncSocket::Receive(void* buffer, size_t length) {
   return CancelableFileOperation(
       &::ReadFile, handle_, reinterpret_cast<char*>(buffer), length,
       &file_operation_, &shutdown_event_, this, INFINITE);
 }

 size_t CancelableSyncSocket::ReceiveWithTimeout(void* buffer,
                                                 size_t length,
                                                 TimeDelta timeout) {
   return CancelableFileOperation(&::ReadFile, handle_,
                                  reinterpret_cast<char*>(buffer), length,
                                  &file_operation_, &shutdown_event_, this,
                                  static_cast<DWORD>(timeout.InMilliseconds()));
 }

 // static
 bool CancelableSyncSocket::CreatePair(CancelableSyncSocket* socket_a,
                                       CancelableSyncSocket* socket_b) {
   return CreatePairImpl(&socket_a->handle_, &socket_b->handle_, true);
 }

 }  // namespace base
	// 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 "base/sync_socket.h"

	#include <limits.h>
	#include <stddef.h>

	#include "base/logging.h"
	#include "base/macros.h"
	#include "base/rand_util.h"
	#include "base/threading/thread_restrictions.h"
	#include "base/win/scoped_handle.h"

	namespace base {

	using win::ScopedHandle;

	namespace {
	// IMPORTANT: do not change how this name is generated because it will break
	// in sandboxed scenarios as we might have by-name policies that allow pipe
	// creation. Also keep the secure random number generation.
	const wchar_t kPipeNameFormat[] = L"\\\\.\\pipe\\chrome.sync.%u.%u.%lu";
	const size_t kPipePathMax = arraysize(kPipeNameFormat) + (3 * 10) + 1;

	// To avoid users sending negative message lengths to Send/Receive
	// we clamp message lengths, which are size_t, to no more than INT_MAX.
	const size_t kMaxMessageLength = static_cast<size_t>(INT_MAX);

	const int kOutBufferSize = 4096;
	const int kInBufferSize = 4096;
	const int kDefaultTimeoutMilliSeconds = 1000;

	bool CreatePairImpl(HANDLE* socket_a, HANDLE* socket_b, bool overlapped) {
	DCHECK_NE(socket_a, socket_b);
	DCHECK_EQ(*socket_a, SyncSocket::kInvalidHandle);
	DCHECK_EQ(*socket_b, SyncSocket::kInvalidHandle);

	wchar_t name[kPipePathMax];
	ScopedHandle handle_a;
	DWORD flags = PIPE_ACCESS_DUPLEX \| FILE_FLAG_FIRST_PIPE_INSTANCE;
	if (overlapped)
	flags \|= FILE_FLAG_OVERLAPPED;

	do {
	unsigned long rnd_name;
	RandBytes(&rnd_name, sizeof(rnd_name));

	swprintf(name, kPipePathMax,
	kPipeNameFormat,
	GetCurrentProcessId(),
	GetCurrentThreadId(),
	rnd_name);

	handle_a.Set(CreateNamedPipeW(
	name,
	flags,
	PIPE_TYPE_BYTE \| PIPE_READMODE_BYTE,
	1,
	kOutBufferSize,
	kInBufferSize,
	kDefaultTimeoutMilliSeconds,
	NULL));
	} while (!handle_a.IsValid() &&
	(GetLastError() == ERROR_PIPE_BUSY));

	if (!handle_a.IsValid()) {
	NOTREACHED();
	return false;
	}

	// The SECURITY_ANONYMOUS flag means that the server side (handle_a) cannot
	// impersonate the client (handle_b). This allows us not to care which side
	// ends up in which side of a privilege boundary.
	flags = SECURITY_SQOS_PRESENT \| SECURITY_ANONYMOUS;
	if (overlapped)
	flags \|= FILE_FLAG_OVERLAPPED;

	ScopedHandle handle_b(CreateFileW(name,
	GENERIC_READ \| GENERIC_WRITE,
	0, // no sharing.
	NULL, // default security attributes.
	OPEN_EXISTING, // opens existing pipe.
	flags,
	NULL)); // no template file.
	if (!handle_b.IsValid()) {
	DPLOG(ERROR) << "CreateFileW failed";
	return false;
	}

	if (!ConnectNamedPipe(handle_a.Get(), NULL)) {
	DWORD error = GetLastError();
	if (error != ERROR_PIPE_CONNECTED) {
	DPLOG(ERROR) << "ConnectNamedPipe failed";
	return false;
	}
	}

	*socket_a = handle_a.Take();
	*socket_b = handle_b.Take();

	return true;
	}

	// Inline helper to avoid having the cast everywhere.
	DWORD GetNextChunkSize(size_t current_pos, size_t max_size) {
	// The following statement is for 64 bit portability.
	return static_cast<DWORD>(((max_size - current_pos) <= UINT_MAX) ?
	(max_size - current_pos) : UINT_MAX);
	}

	// Template function that supports calling ReadFile or WriteFile in an
	// overlapped fashion and waits for IO completion. The function also waits
	// on an event that can be used to cancel the operation. If the operation
	// is cancelled, the function returns and closes the relevant socket object.
	template <typename BufferType, typename Function>
	size_t CancelableFileOperation(Function operation,
	HANDLE file,
	BufferType* buffer,
	size_t length,
	WaitableEvent* io_event,
	WaitableEvent* cancel_event,
	CancelableSyncSocket* socket,
	DWORD timeout_in_ms) {
	AssertBlockingAllowed();
	// The buffer must be byte size or the length check won't make much sense.
	static_assert(sizeof(buffer[0]) == sizeof(char), "incorrect buffer type");
	DCHECK_GT(length, 0u);
	DCHECK_LE(length, kMaxMessageLength);
	DCHECK_NE(file, SyncSocket::kInvalidHandle);

	// Track the finish time so we can calculate the timeout as data is read.
	TimeTicks current_time, finish_time;
	if (timeout_in_ms != INFINITE) {
	current_time = TimeTicks::Now();
	finish_time =
	current_time + base::TimeDelta::FromMilliseconds(timeout_in_ms);
	}

	size_t count = 0;
	do {
	// The OVERLAPPED structure will be modified by ReadFile or WriteFile.
	OVERLAPPED ol = { 0 };
	ol.hEvent = io_event->handle();

	const DWORD chunk = GetNextChunkSize(count, length);
	// This is either the ReadFile or WriteFile call depending on whether
	// we're receiving or sending data.
	DWORD len = 0;
	const BOOL operation_ok = operation(
	file, static_cast<BufferType*>(buffer) + count, chunk, &len, &ol);
	if (!operation_ok) {
	if (::GetLastError() == ERROR_IO_PENDING) {
	HANDLE events[] = { io_event->handle(), cancel_event->handle() };
	const int wait_result = WaitForMultipleObjects(
	arraysize(events), events, FALSE,
	timeout_in_ms == INFINITE ?
	timeout_in_ms :
	static_cast<DWORD>(
	(finish_time - current_time).InMilliseconds()));
	if (wait_result != WAIT_OBJECT_0 + 0) {
	// CancelIo() doesn't synchronously cancel outstanding IO, only marks
	// outstanding IO for cancellation. We must call GetOverlappedResult()
	// below to ensure in flight writes complete before returning.
	CancelIo(file);
	}

	// We set the \|bWait\| parameter to TRUE for GetOverlappedResult() to
	// ensure writes are complete before returning.
	if (!GetOverlappedResult(file, &ol, &len, TRUE))
	len = 0;

	if (wait_result == WAIT_OBJECT_0 + 1) {
	DVLOG(1) << "Shutdown was signaled. Closing socket.";
	socket->Close();
	return count;
	}

	// Timeouts will be handled by the while() condition below since
	// GetOverlappedResult() may complete successfully after CancelIo().
	DCHECK(wait_result == WAIT_OBJECT_0 + 0 \|\| wait_result == WAIT_TIMEOUT);
	} else {
	break;
	}
	}

	count += len;

	// Quit the operation if we can't write/read anymore.
	if (len != chunk)
	break;

	// Since TimeTicks::Now() is expensive, only bother updating the time if we
	// have more work to do.
	if (timeout_in_ms != INFINITE && count < length)
	current_time = base::TimeTicks::Now();
	} while (count < length &&
	(timeout_in_ms == INFINITE \|\| current_time < finish_time));

	return count;
	}

	} // namespace

	#if defined(COMPONENT_BUILD)
	const SyncSocket::Handle SyncSocket::kInvalidHandle = INVALID_HANDLE_VALUE;
	#endif

	SyncSocket::SyncSocket() : handle_(kInvalidHandle) {}

	SyncSocket::~SyncSocket() {
	Close();
	}

	// static
	bool SyncSocket::CreatePair(SyncSocket* socket_a, SyncSocket* socket_b) {
	return CreatePairImpl(&socket_a->handle_, &socket_b->handle_, false);
	}

	// static
	SyncSocket::Handle SyncSocket::UnwrapHandle(
	const TransitDescriptor& descriptor) {
	return descriptor;
	}

	bool SyncSocket::PrepareTransitDescriptor(ProcessHandle peer_process_handle,
	TransitDescriptor* descriptor) {
	DCHECK(descriptor);
	if (!::DuplicateHandle(GetCurrentProcess(), handle(), peer_process_handle,
	descriptor, 0, FALSE, DUPLICATE_SAME_ACCESS)) {
	DPLOG(ERROR) << "Cannot duplicate socket handle for peer process.";
	return false;
	}
	return true;
	}

	bool SyncSocket::Close() {
	if (handle_ == kInvalidHandle)
	return true;

	const BOOL result = CloseHandle(handle_);
	handle_ = kInvalidHandle;
	return result == TRUE;
	}

	size_t SyncSocket::Send(const void* buffer, size_t length) {
	AssertBlockingAllowed();
	DCHECK_GT(length, 0u);
	DCHECK_LE(length, kMaxMessageLength);
	DCHECK_NE(handle_, kInvalidHandle);
	size_t count = 0;
	while (count < length) {
	DWORD len;
	DWORD chunk = GetNextChunkSize(count, length);
	if (::WriteFile(handle_, static_cast<const char*>(buffer) + count, chunk,
	&len, NULL) == FALSE) {
	return count;
	}
	count += len;
	}
	return count;
	}

	size_t SyncSocket::ReceiveWithTimeout(void* buffer,
	size_t length,
	TimeDelta timeout) {
	NOTIMPLEMENTED();
	return 0;
	}

	size_t SyncSocket::Receive(void* buffer, size_t length) {
	AssertBlockingAllowed();
	DCHECK_GT(length, 0u);
	DCHECK_LE(length, kMaxMessageLength);
	DCHECK_NE(handle_, kInvalidHandle);
	size_t count = 0;
	while (count < length) {
	DWORD len;
	DWORD chunk = GetNextChunkSize(count, length);
	if (::ReadFile(handle_, static_cast<char*>(buffer) + count, chunk, &len,
	NULL) == FALSE) {
	return count;
	}
	count += len;
	}
	return count;
	}

	size_t SyncSocket::Peek() {
	DWORD available = 0;
	PeekNamedPipe(handle_, NULL, 0, NULL, &available, NULL);
	return available;
	}

	SyncSocket::Handle SyncSocket::Release() {
	Handle r = handle_;
	handle_ = kInvalidHandle;
	return r;
	}

	CancelableSyncSocket::CancelableSyncSocket()
	: shutdown_event_(base::WaitableEvent::ResetPolicy::MANUAL,
	base::WaitableEvent::InitialState::NOT_SIGNALED),
	file_operation_(base::WaitableEvent::ResetPolicy::MANUAL,
	base::WaitableEvent::InitialState::NOT_SIGNALED) {}

	CancelableSyncSocket::CancelableSyncSocket(Handle handle)
	: SyncSocket(handle),
	shutdown_event_(base::WaitableEvent::ResetPolicy::MANUAL,
	base::WaitableEvent::InitialState::NOT_SIGNALED),
	file_operation_(base::WaitableEvent::ResetPolicy::MANUAL,
	base::WaitableEvent::InitialState::NOT_SIGNALED) {}

	bool CancelableSyncSocket::Shutdown() {
	// This doesn't shut down the pipe immediately, but subsequent Receive or Send
	// methods will fail straight away.
	shutdown_event_.Signal();
	return true;
	}

	bool CancelableSyncSocket::Close() {
	const bool result = SyncSocket::Close();
	shutdown_event_.Reset();
	return result;
	}

	size_t CancelableSyncSocket::Send(const void* buffer, size_t length) {
	static const DWORD kWaitTimeOutInMs = 500;
	return CancelableFileOperation(
	&::WriteFile, handle_, reinterpret_cast<const char*>(buffer), length,
	&file_operation_, &shutdown_event_, this, kWaitTimeOutInMs);
	}

	size_t CancelableSyncSocket::Receive(void* buffer, size_t length) {
	return CancelableFileOperation(
	&::ReadFile, handle_, reinterpret_cast<char*>(buffer), length,
	&file_operation_, &shutdown_event_, this, INFINITE);
	}

	size_t CancelableSyncSocket::ReceiveWithTimeout(void* buffer,
	size_t length,
	TimeDelta timeout) {
	return CancelableFileOperation(&::ReadFile, handle_,
	reinterpret_cast<char*>(buffer), length,
	&file_operation_, &shutdown_event_, this,
	static_cast<DWORD>(timeout.InMilliseconds()));
	}

	// static
	bool CancelableSyncSocket::CreatePair(CancelableSyncSocket* socket_a,
	CancelableSyncSocket* socket_b) {
	return CreatePairImpl(&socket_a->handle_, &socket_b->handle_, true);
	}

	} // namespace base